M
Articles written in Pramana – Journal of Physics
Volume 1 Issue 5 November 1973 pp 235-242 Solids
Volume and surface polarization of electrets
M R Bhiday U Gupta M Ranade S Rao
An attempt is made, to obtain mathematical relations correlating the volume and surface effects of the dielectric to those of the electrical impedance of the dielectric system exhibited in the presence of a quasistatic sinusoidal electrical field. A new experiment is described to differentiate clearly the two types of polarizations in an electret.
Volume 1 Issue 6 December 1973 pp 247-259 Solids
Structure determination of L_{s}-threonine by neutron diffraction
M Ramanadham S K Sikka R Chidambaram
The structure of the aminoacid, L_{s}-threonine [NH_{3}^{+} CH(CHOHCH_{3})COO^{−}], space group
Volume 4 Issue 4 April 1975 pp 153-159 Cosmic Physics
Orbit of the spectroscopic binary b Persei
New spectroscopic orbital elements have been derived for the close binary system b Persei. The period is improved to 1.527360 days. Earlier observations by Cannon (1914), Harper (1930) and Heard (1938) have been reanalysed and the reality of the variations in the orbital elements is established. The change in
Volume 5 Issue 3 September 1975 pp 144-153 Nuclear And Particle Physics
A kinematical basis for power form factors
S G Kamath M Gupta S Chakrabarty A N Mitra
A kinematical basis is proposed for form factors of the power type associated with multiple derivative couplings, on the basis of a Lorentz contraction effect on the external momenta involved in the transition matrix elements for mesons and baryons as appropriate quark composites. The argument (due to Licht and Pagnamenta) which applies separately to the Breit and c.m. frames for a decay matrix element provides a formal theoretical justification for the
Volume 5 Issue 5 November 1975 pp 239-248 Nuclear And Particle Physics
Phenomenological effective interaction for^{40}K
Effective interactions of various forms incorporating central, spin-orbit and tensor dependences of two-nucleon potential are parametrized so as to give a satisfactory description of energy levels of^{40}K. These parameters are applied to calculate energy levels of^{38}Cl. Except for the lowest 3^{−} level, the agreement is satisfactory.
Volume 6 Issue 4 April 1976 pp 235-243 Spectroscopy
The emission band system c^{2}
Five red degraded bands belonging to the
Volume 8 Issue 3 March 1977 pp 205-213 Plasma Physics
Velocity gradient driven flute instabilities in plasmas
The effect of velocity gradient across the magnetic field on the low frequency flute modes is examined in detail, using the normal mode analysis. It is shown that some new type of instabilities driven primarily by the velocity
Volume 8 Issue 3 March 1977 pp 214-216 Plasma Physics
Gravity induced magnetic instability
In the presence of a gravitational field the stability of a magnetoplasma is studied against electromagnetic perturbations. We have shown that a pinching type of instability can be triggered with a sizable growth rate affecting the equilibrium configuration of the confining magnetic field. This might have a profound effect on the magnetic fields of astrophysical bodies.
Volume 8 Issue 3 March 1977 pp 223-228 Atmospheric Physics
The ionospheric absorption at Gauhati
Some problems encountered in the process of estimation of calibration constant
Volume 8 Issue 5 May 1977 pp 478-488 Nuclear And Particle Physics
High resolution gamma-ray spectroscopy of the^{27}Al(
M A Rahman M A Awal M Rahman H M Sengupta S K Gupta
High resolution gamma-ray spectra have been measured from the^{27}Al (
Volume 9 Issue 2 August 1977 pp 103-109 Classical Mechanics
The dirac-schwinger covariance condition in classical field theory
A straightforward derivation of the Dirac-Schwinger covariance condition is given within the framework of classical field theory. The crucial role of the energy continuity equation in the derivation is pointed out. The origin of higher order derivatives of delta function is traced to the presence of higher order derivatives of canonical coordinates and momenta in the energy density functional.
Volume 9 Issue 3 September 1977 pp 297-302 Solids
Experimental results on the nuclear spin-lattice and nuclear spin-spin relaxation times in the ferromagnetic EuB_{6} at temperatures below 4·2 K are presented using the external magnetic field,
Volume 9 Issue 4 October 1977 pp 339-347 Biophysics
Fourier transform of the collagen triple-helical structure and its significance
The Fourier transforms of the collagen molecular structure have been calculated taking into consideration various side chain atoms, as well as the presence of bound water molecules. There is no significant change in the calculated intensity distribution on including the side chain atoms of non-imino-acid residues. Taking into account the presence of about two bound water molecules per tripeptide unit, the agreement with the observed x-ray pattern is slightly improved. Fourier transforms have also been calculated for the detailed molecular geometries proposed from other laboratories. It is found that there are no major differences between them, as compared to our structure, either in the positions of peak intensity or in the intensity distribution. Hence it is not possible to judge the relative merits of the various molecular geometries for the collagen triple helix from a comparison of the calculated transforms with the meagre data available from its x-ray fibre pattern. It is also concluded that the collagen molecular structure should be regarded as a somewhat flexible chain structure, capable of adapting itself to the requirements of the different side groups which occur in each local region.
Volume 9 Issue 5 November 1977 pp 515-521 Atomic Physics
Search for superheavy elements in monazite from beach sands of South India
S S Kapoor V S Ramamurthy M Lal S K Kataria
Monazite minerals obtained from beach sands of South India were examined for the presence of superheavy elements with photon-induced x-ray fluorescence method. The accumulated data of a number of runs each of several days duration do not show any convincing peaks above the background at the expected locations for superheavy elements which are above the present sensitivity of detection of about 10 ppm by weight for element 126. However, some intriguing features pertaining to structures in the x-ray spectra around 27 keV were observed, which are of interest for further investigations.
Volume 10 Issue 1 January 1978 pp 1-10 Solids
Photo and electroluminescence of ZnO : Er and ZnO : Ag, Er electroluminors
A number of ZnO : Er and ZnO : Ag, Er electroluminors have been prepared and their photo (PL) and electroluminescent (EL) properties investigated. While the addition of Ag slightly shifts the PL spectra towards longer wavelength side, the EL spectra not only shift but consist of some new transitions. In ZnO : Er electroluminors, additional transitions also exist at higher frequencies of excitations. Brightness waves for this system consist of two secondary peaks during each half cycle of exciting field. Temperature dependence shows two broad peaks. While voltage dependence of ZnO : Er satisfies the relation
Volume 10 Issue 3 March 1978 pp 329-339 Nuclear Physics
A study of the reaction^{19}F(
M Balakrishnan S Kailas M K Mehta
The total (
Volume 10 Issue 6 June 1978 pp 589-596 Nuclear And Particle Physics
An angular momentum expansion of energy and structure of high spin states
M Satpathy R Sahu A Ansari L Satpathy
A new angular momentum expansion of level energies of ground-state band of even-even nuclei has been obtained which is found to converge rapidly even for the most back-bending nuclei. Attempts have been made to interpret the parameters and calculate them microscopically. It is found that nuclear structure in the forward bending region is quite different compared to that in the back-bending region.
Volume 11 Issue 2 August 1978 pp 195-204 Particle Physics
K Babu Joseph M Sabir M N Sreedharan Nair
An investigation of the newly discovered charmed mesons
Volume 11 Issue 3 September 1978 pp 323-332 Particle Physics
Analysis of multiparticle production data on proton-nucleus collisions using a new variable
T Aziz M Zafar M Irfan A Ahmad M Shafi
Multiparticle production data on proton-nucleus collisions have been analyzed taking the number of ‘created’ charged particles instead of the observed number of shower particles as the variable. The mean normalized multiplicity,
Volume 12 Issue 3 March 1979 pp 263-268 Optics
Output characteristics of a 400 MW Nd:glass laser system
R Bhatnagar P D Gupta B S Narayan M Anwar B L Gupta D D Bhawalkar
The paper discusses the performance characteristics of a Nd: glass laser system designed for laser produced plasma studies. It consists of a
Volume 12 Issue 5 May 1979 pp 447-464 Nuclear And Particle Physics
Long range interactions between some charged solitons
A procedure is offered for evaluating the forces between classical, charged solitons at large distances. This is employed for the solitons of a complex, scalar two-dimensional field theory with a U(1) symmetry, that leads to a conserved charge
Volume 13 Issue 1 July 1979 pp 15-24 Solids
Scattering contributions to the internal partition function of a diatomic molecular system
B Talukdar M Chatterji P Banerjee
An analytical expression for the phase shift contribution to the internal partition function for the Morse potential is derived by using an approximate Jost function. This function is shown to be a convergent sum. The numerical results obtained for H_{2} and HCl show the partition function to be a monotonically increasing function of temperature. This observation agrees with the results of Rogers and co-workers.
Volume 13 Issue 1 July 1979 pp 81-88 Nuclear and Particle Physics
A model for multiparticle production in high energy hadronic collisions
A model for multiparticle production process in high-energy hadronic collisions is proposed. In the centre of mass (CM) system of colliding particles the target and the projectile are assumed to pass through each other sharing energies allowed by kinematical constraints. Thus in a
Volume 13 Issue 2 August 1979 pp 173-181 Nuclear And Particle Physics
M Seetharaman T R Govindarajan P M Mathews
We study the problem of a possible change in the number of constraints in linear relativistic wave equations (-
Volume 13 Issue 4 October 1979 pp 353-365 Plasma Physics
Microwave propagation through modulated air plasma
When a microwave propagates through a plasma in which electron density and electron collision frequency periodically vary, the propagating wave is modulated in amplitude and phase. An approximate theory is derived to suit the laboratory experimental conditions. Introducing the amplitude and phase difference, the dependence of electron density and electron collision frequency has been derived for different radio frequency modulation and frequency parameter. A scanning double probe technique is used to measure the exact time variation in the plasma parameters at any fixed position during a single cycle of the applied field. Theoretical values agree with those of experiment.
Volume 15 Issue 6 December 1980 pp 507-513 Molecular Physics
On the normal vibrations of nonrigid molecule B(CH_{3})_{3}
T S G Krishna Murty L S R K Prasad M Kondala Rao
Treating the symmetry operations as transformations in higher dimensional space, it is shown that Wigner’s method can be straightaway extended to study the vibrations of nonrigid molecules exhibiting free or nearly free internal rotations. The molecule B(CH_{3})_{3} is illustrated.
Volume 16 Issue 1 January 1981 pp 91-98 Quantum Mechanics
Two-potential formula continued off-the-energy-shell
B Talukdar M Chatterji M Kundu
We derive an off-energy-shell generalization of the two-potential formula by using a coordinate-space approach and apply the formalism to construct algorithms for studying spatial behaviour of the fully off-shell
Volume 17 Issue 2 August 1981 pp 121-134 Quantum Mechanics
On the energy spectra of one-dimensional anharmonic oscillators
P M Mathews M Seetharaman Sekhar Raghavan V T A Bhargava
In this paper we present explicit and simple analytical formulae for the energy eigenvalues
Volume 17 Issue 2 August 1981 pp 187-192 Chemical Physics
X-ray K-absorption edge shifts due to chemical combination
K S Srivastava Shiv Singh Pratibha Gupta A K Srivastava V Kumar M Husain M K Prasad
A possible explanation is given of the chemical shifts of x-ray K-absorption edges of metals when they undergo a chemical combination and form compounds. It is proposed that when a metal forms a compound its Fermi edge changes. It explains the numerical order as well as the nature of the chemical shifts. A fairly good agreement between the calculated and observed values has been obtained.
Volume 17 Issue 5 November 1981 pp 381-387 Nuclear And Particle Physics
Generalized interacting boson model and the collective behaviour in nuclei
M Suguna R D Ratna Raju V K B Kota
The effect of including the high spin bosons on the manifestation of collective behaviour in nuclei is examined by plotting the
Volume 17 Issue 5 November 1981 pp 395-404 Nuclear And Particle Physics
Isospin violations in large
H S Mani M Noman M Rafat R Ramachandran
We investigate the asymmetries arising due to electromagnetic interactions in large
Volume 19 Issue 6 December 1982 pp 565-577 Nuclear And Particle Physics
Reaction^{48}Ca (
Gulzar Singh S Kailas S Saini A Chatterjee M Balakrishnan M K Mehta
The total (
Volume 20 Issue 2 February 1983 pp 125-130 Plasma Physics
Multiple focus formation in a Mather gun device
Along with the normally produced pulses of d
Volume 21 Issue 2 August 1983 pp 111-122 Statistical Physics
First passage time distributions for finite one-dimensional random walks
We present closed expressions for the characteristic function of the first passage time distribution for biased and unbiased random walks on finite chains and continuous segments with reflecting boundary conditions. Earlier results on mean first passage times for one-dimensional random walks emerge as special cases. The divergences that result as the boundary is moved out to infinity are exhibited explicitly. For a symmetric random walk on a line, the distribution is an elliptic theta function that goes over into the known Lévy distribution with exponent 1/2 as the boundary tends to ∞.
Volume 21 Issue 3 September 1983 pp 159-169 Solid State Physics
Mechanoluminescence of coloured KCl crystals
M Elyas S K Shukla B P Chandra
The gamma-irradiated KCl crystals exhibit mechanoluminescence during elastic, plastic and fracture deformation. The mechanoluminiscence (
Volume 21 Issue 3 September 1983 pp 187-200 Statistical Physics
First passage time and escape time distributions for continuous time random walks
We consider an arbitrary continuous time random walk (
Volume 22 Issue 6 June 1984 pp 579-587 Instrumentation And Experimental Techniques
On the calculation of second order properties: An equation of motion approach
In the light of the equation of motion method a general expression for polarisability calculation has been derived. From this general expression, different approximation methods can be deduced for different choices of ground state and excitation manifold. Among these the coupled Hartree-Fock theory is the most extensively used one for polarisability calculations. It has also been shown that this theory has a simple relationship with random phase approximation.
Volume 23 Issue 6 December 1984 pp 675-693 Particle Physics
Probing proton spin structure through hadronic reactions
Inclusive and semi-inclusive photon producing polarized proton reactions have been employed to probe the spin structure of the proton. Combinations of cross-sections are suggested which may measure valence quarks polarization and gluon polarization in the proton separately. The general formalism is used to predict numerical results using a model of spin structure based on Altarelli-Parisi equations.
Volume 23 Issue 6 December 1984 pp 721-744 Solid State Physics
Lattice imperfection studies in polycrystalline materials by x-ray diffraction line-profile analysis
This review concerns our recent investigations with a series of binary fcc Ag- and Cu-base alloys (
Volume 23 Issue 6 December 1984 pp 751-765 Solid State Physics
Lattice dynamical study of alkali metals: An unified approach based on CGW model
The phonon dispersion relations for lithium, sodium, potassium, rubidium and cesium along the principal symmetry directions as well as their lattice specific heats have been deduced using Clark, Gazis and Wallis angular force model. This model which conforms to the translational symmetry of the lattice, reproduces the observed crossover in lithium along [ζ00] direction at ζ = 0·49, without producing any crossovers in other alkali metals. Besides, the theoretical dispersion curves of all alkali metals are in excellent agreement with the corresponding experimental or homologous dispersion relations and their
Volume 24 Issue 5 May 1985 pp 695-699 Quantum Mechanics
Exact energy eigenvalues by summation of the
M Seetharaman S S Vasan S Ravichandran
For the potential
Volume 24 Issue 5 May 1985 pp 727-736 Nuclear Physics
On the peripheral nature of the target fragmentation phenomena
The mechanism of target fragmentation phenomena is explored in a statistical model. It is shown that peripheral interaction arising out of large impact parameter can describe the mass yield distribution of the products from the fragmentation of^{63}Cu by the bombardment of
Volume 26 Issue 2 February 1986 pp 151-159 Experimental Techniques
Growth of single crystals of copper and their thermal profile estimation
S K Khanna M Sekar A Michael David K Govinda Rajan P Bhaskar Rao
Copper crystals have been grown by Czochralski technique in a 6-bar argon gas environment. X-ray analysis shows that these are single crystals and are strain-free. A slight pressure environment that is truly hydrostatic seems to improve the quality of the crystals. Thermal profile estimation results show that the values of temperature which decrease upto the neck region are same in magnitude as those measured during the experiments and that necking improves the thermal profile and, consequently, the crystal quality. No facet formation has been observed in these crystals.
Volume 26 Issue 5 May 1986 pp 395-398 Quantum Mechanics
Low energy scattering data and phase shifts
We point out that at any given low energy
Volume 27 Issue 1-2 July 1986 pp 219-231 Plasma Physics
The evolution of nonlinear Langmuir waves in the interplanetary medium is investigated by appropriately accounting for the random density irregularities of the medium. A pair of modified Zakharov equations, which describe these waves, is solved numerically as an initial value problem for large scale (≫ 10^{2} km) initial pertubations. For an ion acoustic-Langmuir solitary wave, the random irregularities damp the Langmuir wave by way of scattering and let the ion density perturbation radiate away in a few days. However an initial solitary or shock-like Langmuir wave excites the ion density perturbations within a fraction of a second, and then itself gets damped. These effects will strongly decelerate the collapse of large scale Langmuir waves. The possibility of detecting these processes, by means of interplanetary scintillation, is discussed.
Volume 27 Issue 5 November 1986 pp 637-646 General Relativity
Spherically symmetric free fall collapse
The general dynamical equations for spherical gravitational collapse are derived by introducing the eigenvalue of the conformal Weyl tensor in the 2-2 component of the Einstein tensor and assuming the material content of the models to be a perfect fluid. Since this eigenvalue is coupled always with the material energy density, it has been interpreted as the
Volume 27 Issue 6 December 1986 pp 747-760 Particle Physics
Elastic and inelastic scattering of 270 MeV^{3}He particles from^{58}Ni,^{90}Zr,^{116}Sn and^{208}Pb
P P Singh Q Li P Schwandt W W Jacobs M Saber E J Stephenson A Saxena S Kailas
Differential cross-section angular distributions for the elastic scattering of 270 MeV^{3}He particles from^{58}Ni,^{90}Zr,^{116}Sn and^{208}Pb have been measured. Optical model analysis of the cross-sections has yielded the optical model parameters for^{3}He particles at 270 MeV. Angular distributions have also been measured for the inelastic excitation of the low-lying levels in the above mentioned nuclei. A collective model analysis using the distorted wave Born approximation (DWBA) of these cross-sections with the distorted waves generated by the optical model parameters determined from the elastic scattering analysis, has yielded the reduced transition probability (B(EL)) values consistent with those reported in the literature.
Volume 27 Issue 6 December 1986 pp 783-793 Particle Physics
Magnetic moments of octet baryons in a chiral potential model
Incorporating the lowest-order pionic correction, the magnetic moments of the nucleon octet have been calculated in a chiral potential model. The potential, representing phenomenologically the nonperturbative gluon interactions including gluon self-couplings, is chosen with equally mixed scalar and vector parts in a power-law form. The results are in reasonable agreement with experiment.
Volume 28 Issue 4 April 1987 pp 415-424
Precession photography of fibres: Prediction of patterns
The Buerger precession method of recording x-ray diffraction patterns can also be used for fibres. This method has some advantages over the conventional flat plate method. Since the fibre has inherent cylindrical symmetry, the precession photograph of the fibre is equivalent to the ‘rotation-precession’ photograph of a single crystal. An analytical prediction of diffraction patterns of the rotation-precession photography is discussed. Also, experimental data are provided to confirm the validity of the equations derived.
Volume 29 Issue 2 August 1987 pp 207-215 Condensed Matter Physics
Dielectric polarization of the solutions of nitrotoluene and cyclohexane
M Śliwińska-Bartkowiak B Szurkowski T Hilczer
Dielectric properties of the solutions of nitrotoluene in cyclohexane showing a far pre-critical state are discussed. Dipolar polarization of the solutions was calculated on the lines of the Onsager model of local field, while the energy of interdipolar interactions was calculated with the help of the dipole-dipole coupling model given by Piekara. The character of interdipolar interactions in the solutions studied was found to be analogous to those in critical solutions at the temperatures from 10 to 20 K higher than the critical temperature.
Volume 29 Issue 4 October 1987 pp 409-417 Condensed Matter Physics
Optical birefringence and order parameter of three nematogens
Results of the measurement of refractive indices and densities of three nematic liquid crystals at different temperatures are reported. The molecular polarizabilities have been calculated from refractive indices using both the Vuks’ and the Neugebauer’s relations. The orientational order parameters are determined from the polarizability values. The variation of order parameter with temperature for these compounds shows a reasonably good agreement with Maier and Saupe theory except near the clearing points where the experimental values are less than those obtained from the theory. The possible reasons for this have been discussed.
Volume 29 Issue 4 October 1987 pp 419-422 Condensed Matter Physics
X-ray and dielectric studies of Sm_{2}(MoO_{4})_{3}
M Roy R N P Choudhary H N Acharya
The polycrystalline samples of Sm_{2}(MoO_{4})_{3} have been prepared by heating appropriate quantities of oxides. The X-ray powder diffraction technique has been used to provide information about lattice parameter, space group and basic structure. The dielectric constant has been measured as a function of frequency (560 Hz-13 MHz) and temperature (30–220°C) to know the ferroelectric transition temperature.
Volume 30 Issue 2 February 1988 pp 143-151 Plasma Physics
Voltage current and power relation in an arc plasma in a variable axial magnetic field
The variation of voltage, current and output power in a mercury arc plasma has been investigated in an axial magnetic field (0–1350 G) for three values of discharge current namely 3, 4 and 5 A. The voltage increases and current decreases almost linearly and the output power also increases with increase of the magnetic field. The conductivity value in magnetic field has been calculated and an analytical expression presented to represent the variation of conductivity in the magnetic field. Utilizing this expression the variation of output power with magnetic field can be explained.
Volume 30 Issue 3 March 1988 pp 193-210 Nuclear Physics
Measurement and analysis of alpha-induced reactions on Ta, Ag and Co
Excitation functions for the reaction^{181}Ta (
Volume 32 Issue 1 January 1989 pp 1-11 Particle Physics
The heavy mesons of the charmonium and upsilon family are described in an alternative static potential model chosen in a combination of Hulthen and linear potential. We find that the quark-confining potential in the form of an equal admixture of vector and scalar parts successfully explains the fine-hyperfine structures of$$c\bar c$$ and$$b\bar b$$ systems in a flavour-independent manner. The leptonic decay widths of the vector mesons of
Volume 32 Issue 2 February 1989 pp 99-105 Mathematical Physics
Determination of eigenvalues of real symmetric para-
V T A Bhargava P M Mathews M Seetharaman
A method is presented for an accurate numerical determination of eigenvalues of real symmetric para-
Volume 32 Issue 2 February 1989 pp 107-115 Quantum Mechanics
Anharmonic oscillators in higher dimension: Accurate energy eigenvalues and matrix elements
V T A Bhargava P M Mathews M Seetharaman
Energy eigenvalues and matrix elements of various anharmonic oscillators are determined to a high accuracy by applying a method for determining the eigenvalues and eigenvectors of real symmetric para-
Volume 32 Issue 4 April 1989 pp 515-521 Statistical Nuclear Physics
Statistical theory of hot nuclei and high spin states
M Rajasekaran N Arunachalam T R Rajasekaran V Devanathan
The hot rotating compound systems formed in heavy ion collisions are studied using the statistical theory with a view to determine the spin and temperature dependence of nuclear shapes. Shape transitions are observed for these systems at particular spin values. The neutron and proton separation energies for heavier high spin systems have been evaluated. Results are presented for_{70}^{170}Yb and_{78}^{194}Pt.
Volume 32 Issue 5 May 1989 pp 605-618 Nuclear Physics
Hybrid model analysis of the excitation function for alpha induced reaction on^{121}Sb and^{123}Sb
Excitation functions for the reactions^{121}Sb(
Volume 32 Issue 6 June 1989 pp 845-845 Erratum
Anharmonic oscillators in higher dimension: Accurate energy eigenvalues and matrix elements
Volume 33 Issue 2 August 1989 pp 315-331 Review Paper
Analytic structure of dynamical systems
The study of the analytic structure of nonlinear ordinary and partial differential equations is shown to provide a unified approach to determining their properties and finding their solutions.
Volume 33 Issue 3 September 1989 pp 397-403 Plasma Physics
Ignition and increase in Pease limit on current in an ohmically heated high density
Energetics of an ohmically heated deuterium-tritium high density
Volume 33 Issue 5 November 1989 pp 541-546 Instrumentation
A microprocessor based autoscanner for electromigration studies in thin films
M Dhanabalan Y Syamasundara Rao K V Reddy
Mass transport due to electromigration can be estimated if the diffusion coefficient
Volume 33 Issue 6 December 1989 pp 659-665 Spectroscopy
Infrared and raman studies on neodymium pentaphosphate and metaphosphates
V Ramakrishnan J Kumar M Thirumavalavan F D Gnanam P Ramasamy
The infrared and Raman spectra of crystalline samples of NdP_{5}O_{14}, NaNdP_{4}O_{12} and KNdP_{4}O_{12} are recorded. The spectra are analysed on the basis of vibrations of P=O, P-O, PO_{2} and P-O-P groups. The P_{4}O_{12}^{4−} ion has cyclic structures both in NaNdP_{4}O_{12} and KNdP_{4}O_{12} crystals. It has been inferred that the P-O-P bridges are stronger in metaphosphates.
Volume 34 Issue 4 April 1990 pp 1- Rapid Communications
M Lal H N Bajpai D Joseph R K Choudhury
Application of energy dispersive X-ray fluorescence (EDXRF) and proton induced X-ray emission (PIXE) methods has been demonstrated for determining the elemental composition of thin film superconducting materials. The results of analysis carried out by EDXRF method have been compared with those obtained by PIXE method. Thin films of YBa_{2}Cu_{3}O_{7} superconducting material were deposited on various substrates such as thin mylar sheet and thick substrates of SrTiO_{3}, MgO and Al_{2}O_{3}. In thin backing the minimum detection limits obtained for Cu, Y, Ba by the PIXE method are 20 ng, 70 ng and 800 ng respectively and the corresponding values by the EDXRF method are 3000 ng, 600 ng and 1000 ng. Detection limits for samples on thick backings deteriorated to a large extent by both methods.
Volume 36 Issue 1 January 1991 pp 95-103 Research Articles
Spherically symmetric static inhomogeneous cosmological models
Spherically symmetric static cosmological models filled with black-body radiation are considered. The models are isotropic about a central observer but inhomogeneous. It is suggested that the energy density of the free gravitational field, which is coupled to the isotropic radiation energy density, might play an important role in generating sufficient field (vacuum) energy (when converted into thermal energy) and initiate processes like inflation. On the central world line the energy density of the free gravitational field vanishes whereas the proper pressure and density of the isotropic black-body radiation are constants. Further, it is shown that the cosmological constant is no more arbitrary but given in terms of the central pressure and density. Also, at its maximum value the energy density of the free gravitational field is proved to be equal to one third of the combined value of radiation pressure and density.
Volume 36 Issue 2 February 1991 pp 207-219
Point contact tunnelling studies on ceramic YBCO with scanning tunnelling microscope tips
H Srikanth M Rajeswari A K Raychaudhuri
A detailed study of point contact tunnelling into ceramic YBCO with electrochemically etched tips of Pt, Nb and W is reported. The superconducting gap parameter (Δ) has been extracted from
Volume 36 Issue 6 June 1991 pp 603-610
Vibrational spectra of (NH_{4})_{3}ZnCl_{5}
M Balasubramanian V Ramakrishnan S Rajendran
IR and Raman spectra of (NH_{4})_{3}ZnCl_{5} have been recorded. The observed spectra have been analysed on the basis of the vibrations of ZnCl_{4}^{2−} and NH_{4}^{+} ions. The appearance of multiple Raman bands indicates the presence of two different types of ammonium ions. The effect of anisotropic crystalline field over the ZnCl_{4} and NH_{4} tetrahedra is also discussed. The assignment of internal modes has been verified by the potential energy distribution calculations.
Volume 37 Issue 1 July 1991 pp 13-20
Modified Hill determinant approach to the eigenvalues of the anharmonic oscillator
The unperturbed Hamiltonian of quantum anharmonic oscillator is modified by introducing a simple variational scale parameter. A suitable choice of this parameter makes the eigenvalues rapidly convergent for small size of the determinant in the method of infinite Hill determinant. Simple analytic expressions for the eigenvalues are obtained by matrix diagonalization method.
Volume 37 Issue 3 September 1991 pp 253-260 Research Articles
Path integral analysis of harmonic oscillators with time-dependent mass
Two cases of forced harmonic oscillators with time dependent mass for which exact propagators can be evaluated are presented. From the exact propagators, normalized solutions of the corresponding Schrödinger equations are arrived at. Time-dependent invariants are also found.
Volume 37 Issue 4 October 1991 pp 321-326
Electron microscopy study of aggregation of microclusters of sulphur
A study of aggregation of sulphur particles in colloidal suspension of sulphur in water-methanol mixture using TEM and electron diffraction is reported. From the micrographs the aggregates formed have been found to be random and tenuous indicating a fractal structure. The electron diffraction patterns of the aggregates are used to study the mechanism of diffusion and reaction limited aggregation.
Volume 38 Issue 1 January 1992 pp 1- Rapid Communication
Transition from order to chaos in SU(2) Yang-Mills-Higgs system
Time-dependent spherically symmetric
Volume 38 Issue 1 January 1992 pp 1-10
Relation between Green’s functions for different potentials
S S Vasan M Seetharaman K Raghunathan
A general relation between the energy-dependent Green’s functions for different potentials is derived in a simple and direct manner. This interesting connection enables the eigenstates of one physical system to be deduced from those of a related system. The derivation is based on the Schrödinger equation and provides an independent justification for the technique of path-dependent time transformation used in path integration.
Volume 38 Issue 1 January 1992 pp 21-29
The general dynamical equations for perfect fluid filled spheres with an outward flux of photons are derived. The vital role played by the energy density of the free gravitational field in accelerating photon production has been emphasized. It is pointed out that even when the material energy density is finite, the energy density of the free gravitational field can take infinitely large values resulting in vanishing surface area of the star. A generalized Schwarzschild interior solution with conformally flat geometry but with photon emission has been obtained. It is pointed out that the interior conformal coordinate system bears a strong resemblance to the exterior Krushkal coordinates. It is shown that for spherical star the invariant velocity of the fluid particles, falling towards the centre, is proportional to its radius suggesting that the outer envelopes collapse at a faster rate than the core part. It is shown that the interior radiating solution can be matched with generalized Schwarzchild exterior solution.
Volume 38 Issue 3 March 1992 pp 291-312
M Dasgupta A Navin Y K Agarwal C V K Baba H C Jain M L Jhingan A Roy
Cross-sections for production of evaporation residues from the compound nucleus^{96}Ru* formed by fusion reactions^{28}Si+^{68}Zn,^{32}S+^{64}Ni,^{37}Cl+^{59}Co and^{45}Sc+^{51}V have been obtained from the yields of their characteristic
Volume 38 Issue 4 April 1992 pp 369-378
Beam couplings and phase conjugate effects in reflection and transmission in BaTiO_{3}
Putcha Venkateswarlu M Moghbel P Chandra Sekhar M C George
The details of experiments showing the effects of self-pumped phase conjugation on reflection and on transmission in barium titanate crystal are given. The specular reflection and the second-surface reflection of an extraordinary polarized beam, incident on the face of the crystal parallel to its
Volume 39 Issue 3 September 1992 pp 305-316 Research Articles
Photoionization of the ground^{1}
M Mohan M Le Dourneuf Vinod Prasad A Kumar
The
Volume 39 Issue 5 November 1992 pp 493-499 Research Articles
Exact bound-state solutions of the cut-off Coulomb potential in
Exact solutions of the potential
Volume 39 Issue 5 November 1992 pp 559-563 Research Articles
Finite size nucleonic effects in the nuclear medium
The finite size effects of nucleons inside a nucleus is investigated. This new approach is entirely different from Hagedorn’s volume correction method and is more rigorous. The size of the nucleon is varied and the magnitude of the hard-core potential is extracted by minimising the energy with respect to the nuclear radius.
Volume 40 Issue 1 January 1993 pp 1- Rapid Communication
On the solution of an anisotropic nonquadratic potential
S S Vasan M Seetharaman K Raghunathan
The Schrodinger-Green function is constructed for an anisotropic non-quadratic potential which has been studied in recent literature. The eigen energies and wavefunctions are readily obtained. Our analysis shows that the wavefunctions given in earlier literature are incorrect and the source of the error is pointed out. A semiclassical treatment of the problem is also presented in support of some of our observations.
Volume 40 Issue 1 January 1993 pp 17-23
Chaos and curvature in a quartic Hamiltonian system
Chaotic behaviour of a quartic oscillator system given by
Volume 40 Issue 3 March 1993 pp 177-187
A JWKB analysis of the sextic anharmonic oscillator in d dimensions
S S Vasan M Seetharaman L Sushama
On the basis of a radial generalization of the JWKB quantization rule, which incorporates higher orders of the approximation, an explicit analytical formula is derived for the energy levels of the three-dimensional sextic anharmonic oscillator. The formula exhibits the scaling property of the exact eigenvalues, and is readily generalized to any dimension. The predicted results are in good agreement with known numerical values.
Volume 40 Issue 3 March 1993 pp 227-251
Excitation function and mean projected recoil ranges of nuclei produced in the
Volume 40 Issue 5 May 1993 pp 367-376
High pressure investigations on amorphous selenium
N V Chandra Shekar M Yousuf P Ch Sahu M Mahendran K Govinda Rajan
We report the diamond anvil cell (DAC) high pressure powder X-ray diffraction studies on amorphous selenium (a-Se) under truly hydrostatic pressure condition up to 20 GPa. Amorphous selenium exhibits a sharp and irreversible transition to a hexagonal structure at 10.6 ± 0.1 GPa. It is also known that metallization occurs in a-Se around this pressure. Some plausible arguments are provided to suggest that the amorphous to crystalline transition may be driven by metallization.
Volume 40 Issue 5 May 1993 pp 391-398
TDPAC studies of Hf doped YBCO
R Govindaraj M Premila Padma Gopalan K P Gopinathan
Time differential perturbed angular correlation measurements of the 133–482 keV
Volume 41 Issue 3 September 1993 pp 271-283 Research Articles
M Krishnamurthy U T Raheja D Mathur
A new ion translational energy spectrometer has been developed to carry out low-energy, gas-phase ion-molecule collision experiments which aim to probe molecular potential energy surfaces. The collisional technique employed relates small changes in the kinetic energy of a projectile ion after it has undergone collision with a static neutral atom/molecule to changes in the overall potential energy of the collision system; information can be furnished about the interaction potential between the projectile and the target. First measurements are reported of a high resolution target excitation spectrum obtained in 1.8 keV collisions of H_{2}^{+} ions with N_{2}. New results pertaining to collision-induced dissociation of CO_{2}^{+} ions are presented and discussed in terms of potential functions of low-lying electronic states of the molecular ion.
Volume 41 Issue 4 October 1993 pp 371-388
Electron impact excitation of Ni XIX using the
Man Mohan M Le Dourneuf A Hibbert V M Burke
Collision strengths for all the transitions between the 15 lowest states of neon-like Ni XIX have been calculated for electron impact in the 80–140 Ry energy range. Configuration-interaction wavefunctions have been used to represent the target states. The standard
Volume 41 Issue 5 November 1993 pp 401-419 Research Articles
A model for the analysis of the heat release from a supercooled liquid at the glass transition
In this paper we present a phenomenological model to analyze the heat release at the glass transition as observed in the continuous cooling calorimetry when a supercooled liquid freezes into the glassy state. We developed this model for the quantitative analysis of the experimental data to obtain the specific heat and the parameters which govern the structural relaxation. A description of the model and the detailed analysis are presented and the relaxation parameters are compared with the corresponding values obtained from the specific heat spectroscopy. Our analysis reveals several interesting aspects which include the effects of delayed enthalpy relaxation and the nonequilibrium structural relaxation time on the observed specific heat, the temperature dependence of the equilibrium configurational specific heat and the validity of the Vogel-Fulcher equation for the relaxation time.
Volume 42 Issue 5 May 1994 pp 435-446
Plasma-maser interaction of langmuir wave with kinetic Alfvén wave turbulence
Bipuljyoti Saikia B K Saikia S Bujarbarua M Nambu
A theoretical study is made on the generation mechanism of Langmuir mode wave in the presence of kinetic Alfvén wave turbulence in a magnetized plasma on the basis of plasma-maser interaction. It is shown that a test high frequency Langmuir mode wave is unstable in the presence of low frequency kinetic Alfvén wave turbulence. The growth of the Langmuir wave occurs due to direct and polarization coupling terms. Because of the universal existence of the kinetic Alfvén waves in large scale plasmas, the results have potential importance in space and astrophysical radiation processes.
Volume 43 Issue 6 December 1994 pp 411-420
A new perturbative approach to the classical anharmonic oscillator
The periodic motion of the classical anharmonic oscillator characterized by the potential
Volume 45 Issue 2 August 1995 pp 165-174
The Coulomb Green’s function revisited
It is demonstrated how the energy-dependent Green’s function for the Schrödinger-Coulomb problem can be deduced from a knowledge of the harmonic oscillator time-propagator. All the known results of the Coulomb system are shown to be elegantly derivable from such a connection.
Volume 45 Issue 3 September 1995 pp 221-226
Theoretical calculation of acoustic non-linearity parameter B/A of binary mixtures
J Jugan Roshan Abraham M Abdulkhadar
Acoustic non-linearity parameter B/A is calculated for five binary liquid mixtures using Tong and Dong equation along with the Flory’s statistical theory. Similar to other excess thermodynamical quantities an excess non-linearity parameter (B/A)^{E} is defined for binary liquid mixtures. The interactions in the liquid mixtures are explained on the basis of the excess non-linearity parameter.
Volume 45 Issue 5 November 1995 pp 431-438
Dielectric properties of nano-particles of zinc sulphide
The dielectric properties of nano-particles of ZnS have been studied over a temperature range from 300 to 525 K. The dielectric constant, dielectric loss and ac conductivity of the samples are larger than those of bulk ZnS crystals. Dielectric properties of composites consisting of nano-particles of Ag of different concentrations dispersed in nano-particles of ZnS have also been studied.
Volume 45 Issue 5 November 1995 pp 439-451
Emission characteristics of a single heterostructure GaAs diode laser are reported using a simple driver circuit. It provides a single picosecond time duration optical pulse, a pulse train or a broad optical pulse depending on the amplitude and time duration of the electrical pump pulse. Results show that relaxation oscillation frequency depends on the amplitude of pumping current pulse as well as on some inherent property of diode laser, which seems to be the level of impurity in lasing medium. Variation of relaxation oscillation frequency with amplitude of current pulse shows only the qualitative agreement with the reported theoretical predictions.
Volume 46 Issue 3 March 1996 pp 229-237 Research Articles
Scaling laws for plasma transport due to
The scale invariance technique has been employed to discuss the
Volume 47 Issue 3 September 1996 pp 255-259
Surface enhanced Raman scattering studies of acetophenone on colloidal silver particles
S Edwin Jayaraj V Ramakrishnan S Perumal M Gurunathan
Intense Raman scattering by acetophenone molecules adsorbed on colloidal silver particles is reported. Greater enhancement is observed for the ring breathing and ring stretching vibrations. The orientation determination analysis shows that the adsorption of acetophenone molecule is neither through its co-ordinating site nor through its
Volume 47 Issue 4 October 1996 pp 331-337
M D Sastry M Moghbel Putcha Venkateswarlu
An impurity mediated mechanism of photorefractive effect in BaTiO_{3} is proposed. The photoinduced changes in the relative concentration of Fe^{3+} in BaTiO_{3} results in an electro-optic coupling through a combination of the Sangster and piezoelectric effects. This is based on the examination of the extensive results on the EPR of Fe^{3+} in the BaTiO_{3} lattice. This model explains the improved photorefractive behavior of BaTiO_{3} on doping with Co^{2+}.
Volume 48 Issue 1 January 1997 pp 163-188 Integrable Systems And Solitons
Localized coherent structures of (2+1) dimensional generalizations of soliton systems
We briefly review the recent progress in obtaining (2+1) dimensional integrable generalizations of soliton equations in (1+1) dimensions. Then, we develop an algorithmic procedure to obtain interesting classes of solutions to these systems. In particular using a Painlevé singularity structure analysis approach, we investigate their integrability properties and obtain their appropriate Hirota bilinearized forms. We identify line solitons and from which we introduce the concept of ghost solitons, which are patently boundary effects characteristic of these (2+1) dimensional integrable systems. Generalizing these solutions, we obtain exponentially localized solutions, namely the dromions which are driven by the boundaries. We also point out the interesting possibility that while the physical field itself may not be localized, either the potential or composite fields may get localized. Finally, the possibility of generating an even wider class of localized solutions is hinted by using curved solitons.
Volume 48 Issue 6 June 1997 pp 1161-1168
Collisional excitation among the seven lowest states of TiXII
Collision strengths have been calculated for electron impact excitation of sodium-like TiXII for all 21 transitions amongst its lowest seven states. Configuration interaction wave functions have been used to represent the target states. The standard and no-exchange
Volume 49 Issue 6 December 1997 pp 623-633
M Ismail R P Sharma M H Rashid
Excitation function and mean projected recoil ranges of nuclei produced in the^{12}C-induced reactions on^{51}V target were measured by conventional stacked foil and thick-target thick-recoil-catcher technique for bombarding energies
Volume 50 Issue 2 February 1998 pp 173-189
Excitation functions and a few isomeric cross-section ratios for production of (1)^{192}Au,^{193}Au,^{194}Au,^{195}Au and^{192}Ir nuclides in
Volume 53 Issue 1 July 1999 pp 3-11 Liquid Crystals And Other Soft Materials
V S K Balagurusamy S Krishna Prasad S Chandrasekhar Sandeep Kumar M Manickam C V Yelamaggad
We have studied the electrical conductivity of well aligned samples of hexahexylthiotriphenylene (HHTT) in the pure as well as doped states. The dopant used was a small concentration (0.62 mole %) of the electron acceptor trinitrofluorenone (TNF). In the columnar phases, doping causes the AC(1 kHz) conductivity along the columnar axis (
We also report the first thermoelectric power studies on these ‘molecular wires’. The sign of the thermoelectric power is in conformity with the expected nature of the charge carriers, namely, holes.
Volume 53 Issue 1 July 1999 pp 131-143 Liquid Crystals And Other Soft Materials
Natural optical activity and liquid crystals
Optical activity of matter is related to the chirality of its constitutive molecules. In liquid crystals, chiral molecules can give rise to superstructures in which the local dielectric tensor rotates in space describing a helix, a fact which greatly enhances the optical activity of the medium. The structures and the optical properties of some helical phases are well-known, as for instance the cholesteric and some chiral smectic phases. For short enough helix pitches, the periodic medium can be considered optically as homogeneous and described by the same constitutive equations used to define the optical properties of solid crystals. Such liquid crystal phases represent an ideal tool to apply the methods, used since a long time in optics, to define homogeneous models for non homogeneous media and to discuss their limits of validity. A brief account is given of the main results recently found in this research area.
Volume 53 Issue 1 July 1999 pp 171-197 Liquid Crystals And Other Soft Materials
Structure and dynamics of charged macromolecules: Minimal representation of biological systems
Structures and functions of various biological macromolecules at cellular levels are controlled by electrostatic, excluded-volume, macromolecular topological connectivity, and hydrodynamic forces. Some aspects of these challenging issues will be addressed. Specifically we will focus our discussions on (a) pattern recognition by macromolecules and complexation, (b) coupling between conformational transitions and phase transitions, (c) chromosomal condensation, (d) collective behavior of charged macromolecules in crowded environments, (e) coupled dynamics of macromolecular assemblies in charged solutions, and (f) polymer transport through pores. Even the simpler synthetic systems exhibit many puzzles which will be resolved using our theoretical formulation. In addition to exploring an understanding of biological processes, the context of fabrication of new synthetic materials will be remarked.
Volume 53 Issue 2 August 1999 pp 289-305
Beta decay of ^{125}Sb and level structures in ^{125}Te
M Sainath K Venkataramaniah P C Sood
The decay of 2.76y ^{125}Sb to levels of ^{125}Te has been studied using an HPGe detector for gamma-ray and a mini orange electron spectrometer for conversion electron measurements. We identify 38 transitions in this decay, including 13 gamma rays and 4 conversion electron lines being reported for the first time. New results also include E1 multipolarity assignments to 3 newly observed transitions and
Volume 53 Issue 3 September 1999 pp 395-404 Nuclear Structure And Dynamics
Experimental investigations of the nuclear level density by using heavy ion reactions
G Viesti M Lunardon D Fabris G Nebbia M Cinausero E Fioretto G Prete JB Natowitz K Hagel R Wada
The transition of the level density parameter
Volume 53 Issue 3 September 1999 pp 409-418 Nuclear Structure And Dynamics
Fusion-fission dynamics in the superheavy nucleus production
G Giardina P D’Agostino G Fazio M Herman AI Muninov A Nasirov G Oliva R Palamara R Ruggeri
The fusion-fission reaction mechanism leading to the massive nucleus formation is studied. We investigate the superheavy nucleus formation in heavy-ion induced reactions by analysing the evaporation residue (ER) production in order to study the fusion dynamics and the decay properties of nuclei close to the stability island at
By using the dinuclear system (DNS) concept of the two interacting nuclei we calculate the quasifission-fusion competition in the entrance channel and the fission-evaporation competition along the de-excitation cascade of the compound nucleus. The dynamics of the entrance channel allows us to determine the beam energy window which is favorable to the fusion, while the dynamic evolution of the compound nucleus on the shell correction to the fission barrier and the dissipative effects influence the fission-evaporation competition in order to obtain the residue nuclei from the superheavy nucleus formation. We also calculate the τ_{n}/τ_{tot} ratio at each step of the de-excitation cascade of the compound nucleus and we present a systematics of τ_{n}/τ_{tot} (at first step of the cascade) for many reactions that lead to nuclei with
Volume 53 Issue 3 September 1999 pp 419-424 Nuclear Structure And Dynamics
Fluctuations of the second order observables for dissipative processes in ^{19}F+^{27}Al system
I Berceanu A Andronic M Duma D MoisĂ M Petrovici A Pop V Simion A del Zoppo G D’Erasmo G Imme G Lanzano A Pagano A Pantaleo G Raciti
The excitation function (EF) data for dissipative processes in ^{19}F + ^{27}Al system in the incident energy interval from 113.5 to 130 MeV are used to obtain the dependence of the charge variance and of the interaction time as a function of the incident energy. Fluctuations are observed in the EFs of both these secondary observables. Their correlation is supported by a mechanism based on stochastic exchange of nucleons.
Volume 53 Issue 3 September 1999 pp 437-441 Nuclear Structure And Dynamics
Dissipative processes in light heavy ion collisions
A Pop A Andronic I Berceanu M Duma D MoisĂ M Petrovici V Simion G Immé G Lanzanò A Pagano G Raciti R Coniglione A Del Zoppo P Piatelli P Sapienza N Colonna G d’Erasmo A Pantaleo
The characteristics of the dissipative processes in the collisions of light heavy ion systems at incident energies below 10 MeV/nucleon have been studied. The correlations between different experimental observables show similar trends as those known at much heavier systems and semiempirical relationships are established starting from assumptions on the nature of the microscopic mechanisms. The charge equilibration process in light systems is also studied.
Volume 53 Issue 3 September 1999 pp 513-520 Nuclear Reactions At Near And Sub-Barrier Energies
Exploiting barrier distributions to investigate breakup effects in the fusion of ^{9}Be+^{208}Pb
M Dasgupta D J Hinde R D Butt A C Berriman C R Morton J O Newton K Hagino
The availability of precisely measured fusion excitation functions have allowed the determination of experimental fusion barrier distributions. This concept is utilised in ^{9}Be+^{208}Pb reaction, to reliably predict the expected complete fusion cross-sections. However, the measured cross-sections are found to be only 68% of those predicted. The large cross-sections observed for incomplete fusion products support the interpretation that this suppression of fusion is caused by ^{9}Be breaking up into charged fragments before reaching the fusion barrier.
Volume 53 Issue 3 September 1999 pp 549-552 Nuclear Reactions At Near And Sub-Barrier Energies
Nuclear orbiting and anomalies in nuclear reactions
A De A Mitra A Ray SR Banerjee M Sengupta A Chatterjee S Kailas HS Patel MG Betigiri SK Dutta
In this paper, we report our measurements of back-angle oxygen and carbon particle yields from ^{16}O+^{89}Y, ^{12}C+^{93}Nb reactions forming the same compound nucleus ^{105}Ag at the same excitation energy and spin distribution. We find anomalously large oxygen yield and entrance channel dependence at high excitation energies from ^{16}O+^{89}Y reaction implying formation of a dinuclear orbiting complex. Possible connection between nuclear orbiting and fast fission is also discussed.
Volume 53 Issue 3 September 1999 pp 563-566 Nuclear Reactions At Near And Sub-Barrier Energies
Fission fragment angular distributions in ^{16}O+^{181}Ta
Bivash R Behera Subinit Roy P Basu M K Sharan S Jena M Satpathy SK Datta L Satpathy ML Chatterjee
Time of flight and energy of fission fragments were measured using pulsed beam. Fission fragment mass and energy integrated angular distributions were extracted. Fission fragment anisotropy was explained in the framework of saddle point model.
Volume 53 Issue 3 September 1999 pp 609-618 Nuclei Act Extreme Conditions
Mass measurements of relativistic projectile fragments in the storage ring ESR
T Radon H Geissel F Attallah K Beckert F Bosch A Dolinskiy H Eickhoff M Falch B Franczak B Franzke Y Fujita M Hausmann M Hellström F Herfurth Th Kerscher O Klepper H-J Kluge C Kozhuharov Yu Litvinov KEG Löbner G Münzenberg F Nolden Yu Novikov Z Patyk W Quint H Reich C Scheidenberger B Schlitt J Stadlmann M Steck K Sümmerer L Vermeeren M Winkler Th Winkler H Wollnik
Two experimental methods of measuring masses of exotic nuclei in the storage ring ESR are presented. Bismuth and nickel fragments were produced via projectile fragmentation, separated and investigated with the combination of the fragment separator FRS and the ESR: (i) Direct mass measurements of relativistic projectile fragments were performed using Schottky mass spectrometry (SMS), i.e., exotic nuclei were stored and cooled in the ESR. Applying electron cooling, the relative velocity spread of circulating low intensity beams can be reduced below 10^{−6}. Under this condition a mass resolving power of up to
Volume 53 Issue 3 September 1999 pp 633-633 Nuclei Act Extreme Conditions
A rare nuclear decay process: The internal conversion between bound atomic states
J F Chemin T Carreyre M Aiche F Attallah G Bogaert J P Grandin M Harston W E Meyerhof J N Scheurer
We shall report on the recently observed dependence of the lifetime of the first excited state in ^{125}Te on the ionic charge state. Then we shall give an interpretation of the dependence of the half-life in terms of a new type of nuclear internal conversion without emission of the electron into the continuum of electron energies. We have named this process internal conversion between bound atomic states or BIC. The resonant character of the BIC will be established and the main parameters governing the decay process will be discussed [1–3].
Finally the results of a recent experiment performed at the GANIL accelerator attempting to measure directly the value of the internal conversion coefficient associated with BIC in ^{125}Te ions with charge states ranging between 44+ and 48+ will be given.
In conclusion we shall discuss the relation between the BIC and nuclear excitation by electron transition, NEET, in the excitation of some nuclear isomeric states.
Volume 53 Issue 3 September 1999 pp 637-646 Nuclei Act Extreme Conditions
Fission experiments with secondary beams
J Benlliure S Steinhäuser C Böckstiegel A Grewe H-G Clerc A heinz M de Jong A R Junghans J Müller K-H Schmidt M Pfützner
Nuclear fission from excitation energies around 11 MeV was studied at GSI, Darmstadt for 76 neutron-deficient actinides and pre-actinides by use of relativistic secondary beams. The characteristics of multimodal fission of nuclei around ^{226}Th are systematically investigated and related to the influence of shell effects on the potential-energy and on the level density between saddle point and scission. A systematic view on the large number of elemental yields measured gave rise to a new interpretation of the enhanced production of even elements in nuclear fission and allowed for a new understanding of pair breaking in fission.
Volume 53 Issue 3 September 1999 pp 647-652 Nuclei Act Extreme Conditions
Statistical fluctuations in hot rotating nuclei
M Rajasekaran D Caleb Chanthi Raj
Thermal fluctuations in angular momentum due to excitation is investigated. Shape changes or structural rearrangement are observed as a consequence of fluctuation in second moment of spin. The uncertainty in angular momentum is considerably enhanced due to thermal fluctuation and is strongly dependent on spin and structural changes.
Volume 53 Issue 4 October 1999 pp 727-731 Research Articles
I I Guseinov BA Mamedov T Özdoğan M Orbay
Using translation formulas for Slater type orbitals (STO’s) the infinite series through the overlap integrals are derived for the magnetic multipole moment integrals. By the use of the derived expressions the magnetic multipole moment integrals, therefore, the magnetic properties of molecules can be evaluated most efficiently and accurately. The convergence of the series is tested by calculating concrete cases. An accuracy of 10^{−5} for the computer results is obtained in the case 2^{p}-pole magnetic moment integrals for 1 ≤
Volume 53 Issue 4 October 1999 pp 733-741 Research Articles
Man Mohan M Le Dourneuf A Hibbert PG Burke
The
Volume 54 Issue 2 February 2000 pp 215-225 Research Articles
Static charged spheres with anisotropic pressure in general relativity
J Krishna Rao M Annapurna MM Trivedi
We report a generalization of our earlier formalism [
Volume 54 Issue 2 February 2000 pp 287-303 Research Articles
Correlation between deformation bleaching and mechanoluminescence in coloured alkali halide crystals
B P Chandra M Ramrakhiani P Sahu A M Rastogi
The present paper reports the correlation between deformation bleaching of coloration and mechanoluminescence (ML) in coloured alkali halide crystals. When the
Volume 54 Issue 4 April 2000 pp 453-453
Volume 54 Issue 5 May 2000 pp 715-727 Research Articles
Collapse of a charged radiating star with shear
The junction conditions for a magnetohydrodynamic fluid sphere undergoing dissipative gravitational collapse in the form of a radial heat flux with shear are obtained. These conditions extend particular results of earlier treatments. We demonstrate that the pressure is proportional to the magnitude of the heat flux as is the case in shear-free models. However in our case the gravitational potentials must be solutions of the Einstein-Maxwell system of equations. The mass function
Volume 54 Issue 5 May 2000 pp 771-776 Research Articles
Coherent structures in presence of dust charge fluctuations
This paper shows the formation of nonlinear coherent structures in a dusty plasma in presence of dust charge fluctuations. Using the typical plasma parameters the potential of the nonlinear coherent structures is derived.
Volume 54 Issue 5 May 2000 pp 777-784 Research Articles
R Mishra S P Tripathy A Kul Shrestha A Srivastava S Ghosh K K Dwivedi D T Khathing M Müller D Fink
In the present work, attempts have been made to investigate the modification in particle track etching response of polyallyl diglycol carbonate (PADC) due to impact of 2 MeV electrons. PADC samples pre-irradiated to 1, 10, 20, 40, 60, 80 and 100 Mrad doses of 2 MeV electrons were further exposed to 140 MeV^{28} Si beam and dose-dependent track registration properties of PADC have been studied. Etch-rate values of the PADC irradiated to 100 Mrad dose electron was found to increase by nearly 4 times that of pristine PADC. The electron irradiation has promoted chain scissioning in PADC, thereby converting the polymer into an easily etchable polymer. Moreover, the etching response and the detection efficiency were found to improve by electron irradiation. Scanning electron microscopy of etched samples further revealed the surface damage in these irradiated PADCs.
Volume 54 Issue 5 May 2000 pp 785-789 Research Articles
Possible lattice formation of new materials within a piezoelectric semiconductor plasma
The possible lattice formation of grains of chosen material in a magnetized current carrying
Volume 55 Issue 1-2 July 2000 pp 327-333
Quantum chromodynamics: Working group report
Sourendu Gupta D Indumathi S Banerjee R Basu M Dittmar RV Gavai F Gelis D Ghosh Sourendu Gupta D Indumathi Asmita Mukherjee
This is the report of the QCD working group at WHEPP-6. Discussions and work on heavy ion collisions, polarized scattering, and collider phenomenology are reported.
Volume 55 Issue 3 September 2000 pp 455-469 Research Articles
Annealing effect on transport properties of Nd_{0.67}Sr_{0.33}MnO_{3} thin films
M Pattabiraman P Murugaraj G Rangarajan V Prasad S V Subramanyam V S Sastry Sang-Mo Koo K V Rao
Annealing dependence of the lattice parameter, resistivity, magnetoresistance and thermopower have been studied on Nd_{0.7}-Sr_{0.33}MnO_{3} thin films deposited on LaAlO_{3} and alumina substrates by pulsed laser ablation. Upon annealing at 800°C and 1000°C the lattice constant of the LaAlO_{3} film tends toward that of the bulk target due to reduction in oxygen vacancies. This results in a metal-insulator transition at temperatures which increase with progressive annealing along with a decrease in the observed low temperature MR. Using a magnon scattering model we estimate the
Volume 55 Issue 5-6 November 2000 pp 751-756 Takamak Plasmas, Contributed Papers
Internal magnetic field measurement in tokamak plasmas using a Zeeman polarimeter
M Jagadeeshwari J Govindarajan
In a tokamak plasma, the poloidal magnetic field profile closely depends on the current density profile. We can deduce the internal magnetic field from the analysis of circular polarization of the spectral lines emitted by the plasma. The theory of the measurement and a detailed design of the Zeeman polarimeter constructed to measure the poloidal field profile in the ADITYA tokamak are presented. The Fabry-Perot which we have employed in our design, with photodiode arrays followed by lock-in detection of the polarization signal, allows the measurement of the fractional circular polarization. In this system He-II line with wavelength 4686 Å is adopted as the monitoring spectral line. The line emission used in the present measurement is not well localized in the plasma, necessiating the use of a spatial inversion procedure to obtain the local values of the field.
Volume 55 Issue 5-6 November 2000 pp 773-779 Laser Plasmas, Contributed Papers
Density oscillations in laser produced plasma decelerated by external magnetic field
This paper presents the dynamics as well as the stability of laser produced plasma expanding across the magnetic field. Observation of some high frequency fluctuations superimposed on ion saturation current along with structuring in the pin hole images of x-ray emitting plasma plume indicate the presence of instability in the plasma. Two type of slope in the variation of x-ray emission with laser intensity in the absence and presence of magnetic field shows appearance of different threshold intensity of laser corresponding to each magnetic field at which this instability or density fluctuation sets on. This instability has been identified as a large Larmor radius instability instead of classical Rayleigh-Taylor (R-T) instability.
Volume 55 Issue 5-6 November 2000 pp 781-787 Laser Plasmas, Contributed Papers
Multiple charge states of titanium ions in laser produced plasma
M Shukla S Bandhyopadhyay V N Rai A V Kilpio H C Pant
An intense laser radiation (10^{12} to 10^{11} W/cm^{−2}) focused on the solid target creates a hot (≥1 keV) and dense plasma having high ionization state. The multiple charged ions with high current densities produced during laser matter interaction have potential application in accelerators as an ion source. This paper presents generation and detection of highly stripped titanium ions (Ti) in laser produced plasma. An Nd:glass laser (KAMETRON) delivering 50 J energy (λ=0.53 µm) in 2.5 ns was focused onto a titanium target to produce plasma. This plasma was allowed to drift across a space of ∼3 m through a diagnostic hole in the focusing mirror before ions are finally detected with the help of electrostatic ion analyzer. Maximum current density was detected for the charge states of +16 and +17 of Ti ions for laser intensity of ∼10^{11} W/cm^{−2}.
Volume 55 Issue 5-6 November 2000 pp 933-939 Plasma Processes, Contributed Papers
Microwave plasma deposition of diamond like carbon coatings
D S Patil K Ramachandran N Venkatramani M Pandey R D’Cunha
The promising applications of the microwave plasmas have been appearing in the fields of chemical processes and semiconductor manufacturing. Applications include surface deposition of all types including diamond/diamond like carbon (DLC) coatings, etching of semiconductors, promotion of organic reactions, etching of polymers to improve bonding of the other materials etc. With a 2.45 GHz. 700 W, microwave induced plasma chemical vapor deposition (CVD) system set up in our laboratory we have deposited diamond like carbon coatings. The microwave plasma generation was effected using a wave guide single mode applicator. We have deposited DLC coatings on the substrates like stainless steel, Cu-Be, Cu and Si. The deposited coatings have been characterized by FTIR, Raman spectroscopy and ellipsometric techniques. The results show that we have achieved depositing ∼95% sp^{3} bonded carbon in the films. The films are unform with golden yellow color. The films are found to be excellent insulators. The ellipsometric measurements of optical constant on silicon substrates indicate that the films are transparent above 900 nm.
Volume 56 Issue 1 January 2001 pp 95-105 Research Articles
Effect of radiative cooling on collapsing charged grains
The effect of the radiative cooling of electrons on the gravitational collapse of cold dust grains with fluctuating electric charge is investigated. We find that the radiative cooling as well as the charge fluctuations, both, enhance the growth rate of the Jeans instability. However, the Jeans length, which is zero for cold grains and nonradiative plasma, becomes finite in the presence of radiative cooling of electrons and is further enhanced due to charge fluctuations of grains resulting in an increased threshold of the spatial scale for the Jeans instability.
Volume 56 Issue 2-3 February 2001 pp 153-159 Foundations Of Quantum Theory
First experimental test of bell inequalities performed using a non-maximally entangled state
M Genovese G Brida C Novero E Predazzi
We describe the realisation of a new test of Bell inequalities using a new scheme obtained by the superposition of type I parametric down conversion produced in two different non-linear crystals pumped by the same laser, but with different polarisations. This experiment is the first test of Bell inequalities using a non-maximally entangled state and thus represents an important step in the direction of eliminating the detection loophole.
Volume 56 Issue 4 April 2001 pp 551-557 Research Articles
RF breakdown by toroidal helicons
Bounded whistlers are well-known for their efficient plasma production capabilities in thin cylindrical tubes. In this paper we shall present their radio frequency (RF) breakdown and discharge sustaining capabilities in toroidal systems. Pulsed RF power in the electronmagnetohydrodynamic (EMHD) frequency regime is fed to the neutral background medium. After the breakdown stage, discharge is sustained by toroidal bounded whistlers. In these pulsed experiments the behaviour of the time evolution of the discharge could be studied in four distinct phases of RF breakdown, steady state attainment, decay and afterglow. In the steady state average electron density of ≈10^{12} per cc and average electron temperature of ≈20 eV are obtained at 10^{−3} mbar of argon filling pressure. Experimental results on toroidal mode structure, background effects and time evolution of the electron distribution function will be presented and their implications in understanding the breakdown mechanism are discussed.
Volume 56 Issue 5 May 2001 pp 657-665 Research Articles
Calculation of minor hysteresis loops under metastable to stable transformations in vortex matter
We present a model in which metastable supercooled phase and stable equilibrium phase of vortex matter coexist in different regions of a sample. Minor hysteresis loops are calculated with the simple assumption of the two phases of vortex matter having field-independent critical current densities. We use our earlier published ideas that the free energy barrier separating the metastable and stable phases reduces as the magnetic induction moves farther from the first order phase transition line, and that metastable to stable transformations occur in local regions of the sample when the local energy dissipation exceeds a critical value. Previously reported anomalous features in minor hysteresis loops are reproduced, and calculated field profiles are presented.
Volume 56 Issue 5 May 2001 pp 667-684 Research Articles
M D Sastry M Moghbel Putcha Venkateswarlu A Darwish
With a view to understanding the role of photo-induced valence changes of impurities in BaTiO_{3} in the phenomena of photorefraction, EPR experiments were conducted under
Volume 56 Issue 5 May 2001 pp 691-696 Brief Reports
On the computation of molecular auxiliary functions
I I Guseinov B A Mamedov M Kara M Orbay
Molecular auxiliary functions
Volume 57 Issue 1 July 2001 pp 115-124 Invited Papers, Others
M Lombardi C Baiocchi A Battistella G Balbinot H Huo-Ja Guoxiang F S Lombardi
The capabilities of a new microstructure, anode point based, for the detection of gas ionizing radiations are presented. For every single detected ionizing radiation it gives a pair of ‘induced’ charges (anodic and cathodic) of the same amount (pulses of the same amplitudes), of opposite sign, with the same collection time and essentially in time coincidence, that are proportional to the primary ionization collected. Each pulse of a pair gives the same energy and timing information, thus one can be used for these information and the other for the position. The complete lack of insulating materials in the active volume of this microstructure avoids problems of charging-up and makes stable and repeatable its behavior. It is possible to observe primary avalanches with a size of more than 2.5 × 10^{7} electrons (4 pC), which give current pulses with a peak of more than 0.26 mA on 100 Ohm and about 30 ns duration, with 5.9 KeV X-rays of ^{55}Fe working in proportional region in 760 Torr of isobutane gas. Single electrons emitted by a heated filament (
Volume 57 Issue 1 July 2001 pp 161-164 Contributed Papers, Nuclear Spectroscopy
Gamma-ray spectroscopy with relativistic exotic heavy-ions
Samit Mandal J Gerl H Geissel K Hauschild M Hellström Z Janas I Kojouharov Y Kopatch RC Lemmon P Mayet Z Podolyak PH Regan H Schaffner C Schlegel J Simpson HJ Wollersheim
Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors (segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed.
Volume 57 Issue 1 July 2001 pp 195-198 Contributed Papers, Nuclear Reactions
Fusion around the barrier for ^{7}Li+^{12}C
A Mukherjee M Dasgupta DJ Hinde CR Morton AC Berriman RD Butt JO Newton H Timmers
Fusion cross-sections for the ^{7}Li + ^{12}C reaction have been measured at energies above the Coulomb barrier by the direct detection of evaporation residues. The heavy evaporation residues with energies below 3 MeV could not be separated out from the α-particles in the spectrum and hence their contribution was estimated using statistical model calculations. The present work indicates that suppression of fusion cross-sections due to the breakup of ^{7}Li may not be significant for ^{7}Li + ^{12}C reaction at energies around the barrier.
Volume 57 Issue 1 July 2001 pp 199-202 Contributed Papers, Nuclear Reactions
Measurement of fission anisotropy for ^{16}O+^{181}Ta
Bivash R Behera Subinit Roy P Basu M K Sharan S Jena M Satpathy M L Chatter Jee S K Datta
Anisotropies in fission fragment angular distributions measured for the system ^{16}O + ^{181}Ta over a range of bombarding energies from 83 MeV to 120 MeV have been analysed. It is shown that statistical transition state model (TSM) with pre-scission neutron correction described adequately the measured anisotropy data. Strong friction parameter is found to be necessary to estimate the pre-saddle to pre-scission neutron ratio.
Volume 57 Issue 1 July 2001 pp 203-207 Contributed Papers, Nuclear Reactions
Deformation effects in the ^{28}Si+^{12}C and ^{28}Si+^{28}Si reactions
C Bhattacharya M Rousseau C Beck V Rauch R M Freeman R Nouicer F Haas O Dorvaux K Eddahbi P Papka O Stezowski S Szilner D Mahboub A Szanto de Toledo A Hachem E Martin S J Sanders
The possible occurrence of highly deformed configurations is investigated in the ^{40}Ca and ^{56}Ni di-nuclear systems as formed in the ^{28}Si + ^{12}C, ^{28}Si reactions by using the properties of emitted light charged particles. Inclusive as well as exclusive data of the heavy fragments and their associated light charged particles have been collected by using the ICARE charged particle multidetector array. The data are analysed by Monte Carlo CASCADE statistical-model calculations using a consistent set of parameters with spin-dependent level densities. Significant deformation effects at high spin are observed as well as an unexpected large ^{8}Be cluster emission of a binary nature.
Volume 57 Issue 2-3 August 2001 pp 285-300
Multiplicity distributions and charged-neutral fluctuations
Tapan K Nayak MM Aggarwal A Agnihotri Z Ahammed ALS Angelis V Antonenko V Arefiev V Astakhov V Avdeitchikov TC Awes PVKS Baba SK Badyal A Baldine L Barabach C Barlag S Bathe B Batiounia T Bernier KB Bhalla VS Bhatia C Blume R Bock E-M Bohne D Bucher A Buijs E-J Buis H Büsching L Carlen V Chalyshev S Chattopadhyay KE Chenawi R Cherbatchev T Chujo A Claussen AC Das MP Decowski V Djordjadze P Donni I Doubovik AK Dubey MR Dutta Majumdar S Eliseev K Enosawa H Feldmann P Foka S Fokin V Frolov MS Ganti S Garpman O Gavrishchuk FJM Geurts TK Ghosh R Glasow SK Gupta B Guskov HA Gustafsson HH Gutbrod R Higuchi I Hrivanacova M Ippolitov H Kalechofsky R Kamermans K-H Kampert K Karadjev K Karpio S Kato S Kees H Kim BW Kolb I Kosarev I Koutcheryaev A Kugler P Kulinich V Kumar M Kurata K Kurita N Kuzmin I Langbein A Lebedev YY Lee H Löhner DP Mahapatra V Manko M Martin A Maximov R Mehdiyev G Mgebrichvili Y Miake D Mikhalev GC Mishra Y Miyamoto B Mohanty D Morrison DS Mukhopadhyay V Myalkovski H Naef BK Nandi SK Nayak TK Nayak S Neumaier A Nianine V Nikitine S Nikolaev S Nishimura P Nomokov J Nystrand FE Obenshain A Oskarsson I Otterlund M Pachr A Parfenov S Pavliouk T Peitzmann V Petracek F Plasil ML Purschke B Raeven J Rak R Raniwala S Raniwala VS Ramamurthy NK Rao F Retiere K Reygers G Roland L Rosselet I Roufanov JM Rubio SS Sambyal R Santo S Sato H Schlagheck H-R Schmidt G Shabratova I Sibiriak T Siemiarczuk BC Sinha N Slavine K Söderström N Solomey G Sood SP Sørensen P Stankus G Stefanek P Steinberg E Stenlund D Stüken M Sumbera T Svensson MD Trivedi A Tsvetkov C Twenhöfel L Tykarski J Urbahn NV Eijndhoven WHV Heeringen GJV Nieuwenhuizen A Vinogradov YP Viyogi A Vodopianov S Vörös MA Vos B Wyslouch K Yagi Y Yokota GR Young
Results from the multiplicity distributions of inclusive photons and charged particles, scaling of particle multiplicities, event-by-event multiplicity fluctuations, and charged-neutral fluctuations in 158
Volume 57 Issue 2-3 August 2001 pp 355-369
First results from RHIC-PHENIX
Tarun Kanti Ghosh K Adcox S S Adler N Ajitanand Y Akiba J Alexander L Aphecetche Y Arai S H Aronson R Averbeck T C Awes K N Barish P D Barnes J Barrette B Bassalleck S Bathe V Baublis A Bazilevsky S Belikov F G Bellaiche S T Belyaev M J Bennett Y Berdnikov S Botelho M L Brooks D S Brown N Bruner D Bucher H Buesching V Bumazhnov G Bunce J Burward-Hoy S Butsyk T A Carey P Chand J Chang W C Chang L L Chavez S Chernichenko C Y Chi J Chiba M Chiu R K Choudhury T Christ T Chujo M S Chung P Chung V Cianciolo B A Cole D G D’Enterria G David H Delagrange A Denisov A Deshpande E J Desmond O Dietzsch B V Dinesh A Drees A Durum D Dutta K Ebisu Y V Efremenko K El Chenawi H En’yo S Esumi L Ewell T Ferdousi D E Fields S L Fokin Z Fraenkel A Franz A D Frawley S-Y Fung S Garpman T K Ghosh A Glenn A L Godoi Y Goto S V Greene M Grosse Perdekamp S K Gupta W Guryn H-Å Gustafsson J S Haggerty H Hamagaki A G Hansen H Hara E P Hartouni R Hayano N Hayashi X He T K Hemmick J Heuser J C Hill D S Ho K Homma B Hong A Hoover T Ichihara K Imai M S Ippolitov M Ishihara B V Jacak W Y Jang J Jia B M Johnson S C Johnson K S Joo S Kametani J H Kang M Kann S S Kapoor S Kelly B Khachaturov A Khanzadeev J Kikuchi D J Kim H J Kim S Y Kim Y G Kim W W Kinnison E Kistenev A Kiyomichi C Klein-Boesing S Klinksiek L Kochenda D Kochetkov V Kochetkov D Koehler T Kohama A Kozlov P J Kroon K Kurita M J Kweon Y Kwon G S Kyle R Lacey J G Lajoie J Lauret A Lebedev D M Lee M J Leitch X H Li Z Li D J Lim M X Liu X Liu Z Liu C F Maguire J Mahon Y I Makdisi V I Manko Y Mao S K Mark S Markacs G Martinez M D Marx A Masaike F Matathias T Matsumoto P L McGaughey E Melnikov M Merschmeier F Messer M Messer Y Miake T E Miller A Milov S Mioduszewski R E Mischke G C Mishra J T Mitchell A K Mohanty D P Morrison J M Moss F Mühlbacher M Muniruzzaman J Murata S Nagamiya Y Nagasaka J L Nagle Y Nakada B K Nandi J Newby L Nikkinen P Nilsson S Nishimura A S Nyanin J Nystrand E O’Brien C A Ogilvie H Ohnishi I D Ojha M Ono V Onuchin A Oskarsson L Österman I Otterlund K Oyama L Paffrath A P T Palounek V S Pantuev V Papavassiliou S F Pate T Peitzmann A N Petridis C Pinkenburg R P Pisani P Pitukhin F Plasil M Pollack K Pope M L Purschke I Ravinovich K F Read K Reygers V Riabov Y Riabov M Rosati A A Rose S S Ryu N Saito A Sakaguchi T Sakaguchi H Sako T Sakuma V Samsonov T C Sangster R Santo H D Sato S Sato S Sawada B R Schlei Y Schutz V Semenov R Seto T K Shea I Shein T-A Shibata K Shigaki T Shiina Y H Shin I G Sibiriak D Silvermyr K S Sim J Simon-Gillo C P Singh V Singh M Sivertz A Soldatov R A Soltz S Sorensen P W Stankus N Starinsky P Steinberg E Stenlund A Ster S P Stoll M Sugioka T Sugitate J P Sullivan Y Sumi Z Sun M Suzuki E M Takagui A Taketani M Tamai K H Tanaka Y Tanaka E Taniguchi M J Tannenbaum J Thomas J H Thomas T L Thomas W Tian J Tojo H Torii R S Towell I Tserruya H Tsuruoka A A Tsvetkov S K Tuli H Tydesjö N Tyurin T Ushiroda H W van Hecke C Velissaris J Velkovska M Velkovsky A A Vinogradov M A Volkov A Vorobyov E Vznuzdaev H Wang Y Watanabe S N White C Witzig F K Wohn C L Woody W Xie K Yagi S Yokkaichi G R Young I E Yushmanov W A Zajc Z Zhang S Zhou
The PHENIX experiment consists of a large detector system located at the newly commissioned relativistic heavy ion collider (RHIC) at the Brookhaven National Laboratory. The primary goal of the PHENIX experiment is to look for signatures of the QCD prediction of a deconfined high-energy-density phase of nuclear matter quark gluon plasma. PHENIX started data taking for Au+Au collisions at √
Volume 57 Issue 2-3 August 2001 pp 399-416
Meson production in
H Machner M Betigeri J Bojowald A Budzanowski A Chatterjee J Ernst L Freindl D Frekers W Garske K Grewer A Hamacher J Ilieva L Jarczyk K Kilian S Kliczewski W Klimala D Kolev T Kutsarova J Lieb H Machner A Magiera H Nann L Pentchev HS Plendl D Protić B Razen P Von Rossen BJ Roy R Siudak J Smyrski RV Srikantiah A Strzałkowski R Tsenov K Zwoll
Total and differential cross sections for the reactions
Volume 57 Issue 2-3 August 2001 pp 445-457
Parametrization of nuclear parton distributions
Optimum nuclear parton distributions are obtained by analysing available experimental data on electron and muon deep inelastic scattering (DIS). The distributions are given at
Volume 57 Issue 2-3 August 2001 pp 469-479
Open problems in formation and decay of composite systems in heavy ion reactions
G Viesti V Rizzi M Barbui D Fabris M Lunardon G Nebbia S Moretto S Pesente M Cinausero E Fioretto G Prete D Shetty
New highly exclusive experiments in the field of formation and decay of composite systems in heavy ion reactions are presented. Dynamical effects are reviewed in the light of recent works on the role of the
Volume 57 Issue 2-3 August 2001 pp 535-544
Structure of light neutron-rich nuclei through coulomb dissociation
U Datta Pramanik T Aumann D Cortina H Emling H Geissel M Hellström R Holzmann N Iwasa Y Leifels G Münzenberg M Rejmund C Scheidenberger K Sümmerer A Leistenschneider Th W Elze A Grünschloss S Ilievski K Boretzky J V Kratz R Kulessa E Lubkiewicz E Wajda W Walus P Reiter H Simon
Coulomb breakup of neutron-rich nuclei around mass
Volume 57 Issue 4 October 2001 pp 809-820 Research Articles
Near surface composition of some alloys by X-ray photoelectron spectroscopy
Chemical compositions of the alloys of CuNi (Cu_{0.10}Ni_{0.90}, Cu_{0.30}Ni_{0.70}, Cu_{0.70}Ni_{0.30}) and BiSb (Bi_{0.80}Sb_{0.20}, Bi_{0.64}Sb_{0.34}, Bi_{0.55}Sb_{0.45}) are determined by X-ray photoelectron spectroscopy. The stoichiometries are determined and are compared with the bulk compositions. Possible sources of systematic errors contributing to the results are discussed. Errors arising out of preferential etching in these alloys have been investigated. It has been inferred from such studies that the preferential etching does not enrich the surface composition with a particular component for the two systems reported here. Quantitative results of CuNi system indicate that the surface regions of the Cu_{0.70}Ni_{0.30} alloy is Cu-rich, although no such evidence is observed in case of BiSb system.
Volume 57 Issue 5-6 November 2001 pp 849-869 Fundamental Aspects of Solitons, Fibre Optics And Nonlinear Materials
Optical fiber communication—An overview
This paper deals with the historical development of optical communication systems and their failures initially. Then the different generations in optical fiber communication along with their features are discussed. Some aspects of total internal reflection, different types of fibers along with their size and refractive index profile, dispersion and loss mechanisms are also mentioned. Finally the general system of optical fiber communication is briefly mentioned along with its advantages and limitations. Future soliton based optical fiber communication is also highlighted.
Volume 57 Issue 5-6 November 2001 pp 885-916 Theoretical Aspects Of Optical Solitons
Coupled nonlinear Schrödinger equations (CNLS) very often represent wave propagation in optical media such as multicore fibers, photorefractive materials and so on. We consider specifically the pulse propagation in integrable CNLS equations (generalized Manakov systems). We point out that these systems possess novel exact soliton type pulses which are shape changing under collision leading to an intensity redistribution. The shape changes correspond to linear fractional transformations allowing for the possibility of construction of logic gates and Turing equivalent all optical computers in homogeneous bulk media as shown by Steiglitz recently. Special cases of such solitons correspond to the recently much discussed partially coherent stationary solitons (PCS). In this paper, we review critically the recent developments regarding the above properties with particular reference to 2-CNLS.
Volume 57 Issue 5-6 November 2001 pp 917-936 Theoretical Aspects Of Optical Solitons
A variational approach to nonlinear evolution equations in optics
A tutorial review is presented of the use of direct variational methods based on Rayleigh-Ritz optimization for finding approximate solutions to various nonlinear evolution equations. The practical application of the approach is demonstrated by some illustrative examples in connection with the nonlinear Schrödinger equation.
Volume 58 Issue 2 February 2002 pp 241-257
Charge densities and charge noise in mesoscopic conductors
We introduce a hierarchy of density of states to characterize the charge distribution in a mesoscopic conductor. At the bottom of this hierarchy are the partial density of states which represent the contribution to the local density of states if both the incident and the out-going scattering channel is prescribed. The partial density of states play a prominent role in measurements with a scanning tunneling microscope on multiprobe conductors in the presence of current flow. The partial density of states determine the degree of dephasing generated by a weakly coupled voltage probe. In addition the partial density of states determine the frequency-dependent response of mesoscopic conductors in the presence of slowly oscillating voltages applied to the contacts of the sample. The partial density of states permit the formulation of a Friedel sum rule which can be applied locally. We introduce the off-diagonal elements of the partial density of states matrix to describe charge fluctuation processes. This generalization leads to a local Wigner-Smith life-time matrix.
Volume 58 Issue 5-6 May 2002 pp 715-723 Strongly Correlated Electron Systems
Magnetotransport of the low-carrier density one-dimensional
P Gegenwart H Aoki T Cichorek J Custers M Jaime A Ochiai F Steglich
The transport properties of the semimetallic quasi-one-dimensional
Volume 58 Issue 5-6 May 2002 pp 761-767 Strongly Correlated Electron Systems
V V Krishnamurthy M Suzuki N Kawamura T Ishikawa
The formation of induced 5
Volume 58 Issue 5-6 May 2002 pp 777-782 Strongly Correlated Electron Systems
Spin-glass, antiferromagnetism and kondo behavior in Ce_{2}Au_{1−x}Co_{x}Si_{3} alloys
Subham Majumdar EV Sampathkumaran St Berger M Della Mea H Michor E Bauer M Brando J Hemberger A Loidl
Recently, the solid solution Ce_{2}Au_{1−}_{x}_{Co}
Volume 58 Issue 5-6 May 2002 pp 783-786 Strongly Correlated Electron Systems
Studies on the valence electronic structure of Fe and Ni in Fe_{x}Ni_{1−x} alloys
DK Basa S Raj HC Padhi M Polasik F Pawlowski
Volume 58 Issue 5-6 May 2002 pp 809-815 Superconductivity
VPS Awana M Karppinen H Yamauchi
Both RuSr_{2}GdCu_{2}O_{8-δ} (Ru-1212) and RuSr_{2}Gd_{1.5}Ce_{0.5}Cu_{2}O_{10-δ} (Ru-1222) exhibits magnetism and superconductivity, as seen by magnetization vs. temperature behavior measured in 5 Oe field. Zero-field-cooled (ZFC) and field-cooled (FC) magnetization data show branching at around 140 K and 100 K with a cusp at 135 K and 80 K and a diamagnetic transition around 20 K and 30 K in the ZFC part, for Ru-1212 and Ru-1222, respectively. The isothermal magnetization possesses a non-linear contribution due to a ferromagnetic component at low temperatures below 50 K for both samples. The resistance vs. temperature behavior of the samples in applied fields of 0, 3 and 7 T confirmed superconductivity, with a different type of broadening of the superconductivity transition under magnetic fields for Ru-1212 from that known for conventional high-
Volume 58 Issue 5-6 May 2002 pp 877-880 Superconductivity
S Rayaprol Krushna Mavani CM Thaker DS Rana Keka Chakravorty SK Paranjape M Ramanadham Nilesh A Kulkarni DG Kuberkar
A new series of mixed oxide superconductors with the stoichiometric composition La_{2−x}Dy_{x}Ca_{y}Ba_{2}Cu_{4+y}O_{z} (
Volume 58 Issue 5-6 May 2002 pp 1013-1017 Colossal Magnetoresistance And Other Materials
Polarized Raman scattering in single crystals of Nd_{0.7}Sr_{0.3}MnO_{3}
M Pattabiraman G Rangarajan Kwang-Yong Choi P Lemmens G Guentherodt G Balakrishnan DMcK Paul MR Lees
We report polarized Raman scattering in single crystals of Nd_{0.7}Sr_{0.3}MnO_{3}. The temperature dependence of the MnO_{6} octahedral bending and stretching modes observed in the XX spectra points to the existence of local lattice distortions, possibly polarons. The XY spectra have been analyzed using a collision-dominated model, which allows the extraction of the carrier scattering rate.
Volume 59 Issue 3 September 2002 pp 525-529
A new ultrasonic method to detect chemical additives in branded milk
S Mohanan P G Thomas Panicker Lilly Iype M Laila I Domini RG Bindu
A new ultrasonic method — thermoacoustic analysis — is reported for the detection of the added chemical preservatives in branded milk. The nature of variation and shift in the thermal response of the acoustic parameters specific acoustic impedance, adiabatic compressibility and Rao’s specific sound velocity for different samples of branded milk as compared to the chemical added pure milk are explained as due to the presence of chemicals in these branded samples.
Volume 59 Issue 5 November 2002 pp 725-737
R Hellborg K Hākansson M Faarinen M Kiisk P Persson G Skog K Stenström
A recirculating terminal pumping system has been installed in the 3 MV Pelletron tandem accelerator in Lund. An extremly limited space in the high voltage terminal and the absence of electrical power in the terminal, forced us to provide a unique design for the installation and powering of the new pumps. Details of the technical design, as well as experience of the use of the new system for accelerator mass spectrometry, will be given.
Volume 59 Issue 5 November 2002 pp 753-759
New modifications in 15 UD pelletron at nuclear science centre
S Chopra N S Pawar M P Singh Rakesh Kumar J Prasad V P Patel Raj Pal B Kumar S Ojha K Devarani T Nandi M Sota P Barua S Gargari R Joshi D Kanjilal SK Datta
The 15 UD pelletron at NSC has been operational and performed well during the last 11 years. There have been major modifications performed for upgradation of pelletron system over this period. Major upgradations which have been implemented are new resistor network system for voltage gradient, doublet to singlet unit conversion for accelerator units, turbopump based gas stripper system etc. In addition accelerator mass spectroscopy program has also been started. A new multi-cathode source, Wien filter etc. have been procured and will be added soon in the system. An overview of the most significant upgradations undertaken and other activities for the system are being reported in the present paper.
Volume 59 Issue 5 November 2002 pp 765-773
An EBIS for charge state breeding in the SPES project
V Variale G Brautti T Clauser A Rainò V Stagno G Lamanna V Valentino A Boggia Y Boimelshtein P Logatchov B Skarbo M Tiunov
The ‘charge state breeder’, BRIC (breeding ion charge) is in construction at the INFN section of Bari (Italy). It is based on EBIS scheme and it is designed to accept radioactive ion beam (RIB) with charge state +1 in a slow injection mode. This experiment can be considered as a first step towards the design and construction of a charge breeder for the SPES project.
The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion chamber, of a rf-quadrupole aiming at filtering the unwanted masses and then making a more efficient containment of the wanted ions. In this paper, the breeder design, the simulation results of the electron and ion beam propagation and the construction problems of the device will be reported.
Volume 59 Issue 6 December 2002 pp 957-962
The design of a radio frequency quadrupole LINAC for the RIB project at VECC Kolkata
V Banerjee Alok Chakrabarti Arup Bandyopadhyay T K Bhaumik M Mondal T K Chakraborty H Pande O Kamigaito A Goto Y Yano
A radio frequency quadrupole LINAC has been designed for the VECC-RIB project for an input beam energy of 1.0 keV/u and
Volume 59 Issue 6 December 2002 pp 1053-1059
A small and compact AMS facility for tritium depth profiling
M Friedrich W Pilz N Bekris M Glugla M Kiisk V Liechtenstein
Depth profiling measurements of tritium in carbon samples have been performed during the past seven years at the AMS facility installed at the Rossendorf 3 MV Tandetron. The samples have been cut from the inner walls of the fusion experiments ASDEX-upgrade/Garching and JET/Culham. The tritium content of the samples from JET required a dedicated AMS facility to prevent any contamination of the versatile 3 MV Tandetron. On the basis of an air-insulated 100 kV tandem accelerator equipped with a gas stripper an AMS facility exclusively devoted to tritium depth profiling was installed, tested and used for routine measurements. After additional successful tests employing diamond-like carbon (DLC) stripper foils at this accelerator, another small and compact 100 kV tandem accelerator with SF_{6} insulation and a DLC stripper has been installed at the AMS facility. Results obtained with the different tandem accelerators are presented.
Volume 59 Issue 6 December 2002 pp 1061-1073
A high resolution AMS-injector for the Pelletron in Lund
R Hellborg S Bazhal M Faarinen K Håkansson C-E Magnusson P Persson G Skog K Stenström
A high resolution injector system has recently been installed at the Lund 3 MV tandem Pelletron accelerator. The new injector, designed mainly for ^{26}Al ions, will increase the experimental potential of the Lund AMS facility considerably. High quality energy- and mass-resolution is obtained by using a 90° spherical electrostatic analyzer followed by a 90° magnetic analyzer. The injector is equipped with a high intensity sputtering source with a spherical ionizer.
A new analytical technique for acceptance calculations as well as PC-based computational methods have been used in the design of the ion optical system of the new injector.
Compared to our old injector system which has a magnetic analyzer with a bending angle of only 15°, the new system has a more than ten times better resolution. The beam optics of the new system is also better designed to match the accelerator acceptance. In this way the ion transmission from the ion source to the detector, for different ions of interest in our AMS programme, has been increased.
Volume 62 Issue 1 January 2004 pp 53-60
Optimization and performance of a high-speed plasma position digital control system
M Emami A R Babazadeh H Rasouli
This paper addresses optimization of a high-speed digital feedback controller for a plasma position in Damavand tokamak. Damavand tokamak discharges have plasma currents up to 40 kA with discharge duration greater than 15 ms and toroidal magnetic fields up to 1.2 T. The plasma position is measured using saddle-loops and Rogowski coil and is controlled by electromagnetic forces generated by passing currents through control coils placed around the plasma. A desired control objective is maintaining the plasma in the center of vacuum vessel and to stabilize the plasma in the presence of disturbances in a time domain of the order of few milliseconds. In order to achieve maximum performance it is essential to optimize the control system. In this paper plasma position measurement and the details of implementing high-speed PID controllers based on a TMS320c25 digital signal processor along with the system optimization are presented.
Volume 64 Issue 6 June 2005 pp 981-989
Polymer mixtures in confined geometries: Model systems to explore phase transitions
K Binder M Müller A Cavallo E V Albano
While binary (A,B) symmetric polymer mixtures in
Volume 64 Issue 6 June 2005 pp 1121-1125
Measuring information networks
Traffic and communication between different parts of a complex system are fundamental elements in maintaining its overall cooperativity. Because a complex system consists of many different parts, it matters where signals are transmitted. Thus signaling and traffic are in principle specific, with each message going from a unique sender to a specific recipient. In the current paper we review some measures of network topology that are related to its ability to direct specific communication.
Volume 64 Issue 6 June 2005 pp 1127-1134
Fusion of biological membranes
The process of membrane fusion has been examined by Monte Carlo simulation, and is found to be very different than the conventional picture. The differences in mechanism lead to several predictions, in particular that fusion is accompanied by transient leakage. This prediction has recently been verified. Self-consistent field theory is applied to examine the free energy barriers in the different scenarios.
Volume 67 Issue 1 July 2006 pp 47-55
Combined neutron and synchrotron studies of magnetic films
Sunil K Sinha S Roy M R Fitzsimmons S Park M Dorn O Petracic I V Roshchin Zhi Pan Li X Batlle R Morales A Misra X Zhang K Chesnel J B Kortright Ivan K Schuller
We discuss specular reflectivity and off-specular scattering of neutrons and X-rays from magnetic films. Both these techniques are capable of providing information about the morphology of the chemical and magnetic roughness and the magnetic domain structure. The use of neutrons with polarization analysis enables the spatial distribution of different vector components of the magnetization to be determined, and the use of resonant magnetic X-ray scattering enables magnetization in a compound system to be determined element-selectively. Thus both these methods provide powerful and complementary new probes for studying magnetism at the nanoscopic level in a variety of systems such as those exhibiting exchange bias, giant magnetoresistance, spin injection, etc. We shall illustrate with an example of both techniques applied to an exchange bias system consisting of a single crystal of antiferromagnetic FeF_{2} capped with a ferromagnetic Co film, and discuss what has been learned about how exchange bias works in such a system.
Volume 67 Issue 1 July 2006 pp 153-162
Metal-insulator transition in Ni-doped Na_{0.75}CoO_{2}: Insights from infrared studies
M Premila A Bharathi N Gayathri P Yasodha Y Hariharan C S Sundar
Nickel substitution at the cobalt site in Na_{0.75}CoO_{2} induces an upturn in the resistivity on lowering the temperature, with the metal-to-insulator transition temperature (
Volume 67 Issue 1 July 2006 pp 199-205
G H Döhler M Eckardt A Schwanhäußer F Renner S Malzer S Trumm M Betz F Sotier A Leitenstorfer G Loata T Löffler H Roskos T Müller K Unterrainer D Driscoll M Hanson A C Gossard
By suitable design it is possible to achieve quasi-ballistic transport in semiconductor nanostructures over times up to the ps-range. Monte-Carlo simulations reveal that under these conditions phase-coherent real-space oscillations of an electron ensemble, generated by fs-pulses become possible in wide potential wells. Using a two-color pump-and-probe technique we have been able to observe this new phenomenon in excellent agreement with the theoretical predictions. Apart from its fundamental significance, ballistic transport in nanostructures can also be used for high-efficiency coherent THz-sources. The concept of these THz-emitters and its experimental confirmation will also be presented.
Volume 67 Issue 2 August 2006 pp 257-268 Research Articles
Elliptic flow in a hadron-string cascade model at 130 GeV energy
P K Sahu A Ohnishi M Isse N Otuka S C Phatak
We present the analysis of elliptic flow at $$\sqrt s $$=130 A GeV energy in a hadron-string cascade model. We find that the final hadronic yields are qualitatively described. The elliptic flow
Volume 67 Issue 4 October 2006 pp 735-742 Working Group 2: Neutrino And Astroparticle Physics
Working group report: Astroparticle and neutrino physics
Raj Gandhi Subhendra Mohanty Tarun Souradeep S Agarwalla K Bhattacharya B Brahmachari R Crittenden S Goswami P Ghoshal M Lindner H S Mani S Mitra S Pascoli S Panda R Rangarajan S Ray T Roy Choudhury R Saha S Sarkar A Srivastava R Sheth S Uma Sankar U Yajnik
The working group on astroparticle and neutrino physics at WHEPP-9 covered a wide range of topics. The main topics were neutrino physics at INO, neutrino astronomy and recent constraints on dark energy coming from cosmological observations of large scale structure and CMB anisotropy.
Volume 67 Issue 5 November 2006 pp 821-833
Beyond the new standard model in neutrino oscillations
We discuss effects of new physics (NP) in neutrino oscillation experiments. Such effects can modify a production neutrino flux, a detection cross-section and a matter transition. As a result, the NP effects change neutrino oscillations both in vacuum and in matter. A relation between the small effects of NP and the oscillation parameters is discussed. It is shown for which parameters the NP effects are suppressed and when they are potentially large. Oscillations of non-unitary mixed neutrinos are presented in more details.
Volume 67 Issue 6 December 2006 pp 1073-1086 Research Articles
Hierarchy of rational order families of chaotic maps with an invariant measure
M A Jafarizadeh M Foroutan S Ahadpour
We introduce an interesting hierarchy of rational order chaotic maps that possess an invariant measure. In contrast to the previously introduced hierarchy of chaotic maps [1–5], with merely entropy production, the rational order chaotic maps can simultaneously produce and consume entropy. We compute the Kolmogorov-Sinai entropy of these maps analytically and also their Lyapunov exponent numerically, where the obtained numerical results support the analytical calculations.
Volume 67 Issue 6 December 2006 pp 1119-1128 Research Articles
Pulsed pump: Thermal effects in solid state lasers under super-Gaussian pulses
Solid state laser (SSL) powers can be realistically scaled when pumped by a real, efficient and multimode pulse. In this work, a fourth-order super-Gaussian pulse was assumed as a pump for SSL’s and a complete analytical expression for the thermal phase shift is given. Moreover, the focal length of thermal lens in paraxial ray approximation regime was studied. The results when applied to a Ti: sapphire crystal show an appreciable correction for abberation compared to a top-hat pulse.
Volume 86 Issue 3 March 2016 pp 555-563 Regular
Hasheminia M Mirjalili A Zomorrodian M E Sepehri A
The analysis of electron–positron annihilations to hadrons at high energies shows that apart from two-jet events, there are also signs of three-jet events which are interpreted according to the QCD, as a gluon radiated by a quark. In this paper, we investigate the fragmentation of quarks and gluons to hadron jets. We show that gluon jets have a higher multiplicity compared to quark jets of the same energy. Furthermore, inclusion of different flavours in the distributions shows that quark jets are flavour-dependent, but gluon jets are not. The differences between quark and gluon jets also manifest themselves in the fragmentation functions. We observe that the fragmentation for gluon jet is softer than that for quark jet, because the radiation of soft gluons is larger for gluon jetsand that gluon cannot be present as a valence parton inside a produced hadron. We provide possible explanations for these features in this paper.
Volume 86 Issue 3 March 2016 pp 609-615 Regular
Sivananatham M Tata B V R Aswal V K
Small-angle neutron scattering (SANS) and ultraviolet (UV)–visible spectroscopictechniques are used to investigate the microstructural changes in polyacrylamide (PAAm) hydrogels on gamma irradiation. SANS measurements have revealed the presence of inhomogeneities in nanometre scale and reduction of their size with increase in dose. Analysis of SANS data alsorevealed the increase in the correlation length with increase in dose. The extinction coefficient obtained from the UV–visible spectroscopic studies exhibited $\lambda^{−\beta}$ dependence between 500 and 700 nm and is understood to arise from the existence of scatterers (inhomogeneities) in submicron scale in PAAm hydrogels. The increase in value of exponent $\beta$ with increase in dose indicates that the size of scatterers decrease with increase in dose.
Volume 86 Issue 3 March 2016 pp 669-680 Regular
In this paper, a detailed numerical study of the role of selected soliton distributions on the spin-dependent transport through {\it trans}-polyacetylene (PA) molecule is presented. The molecule is attached symmetrically to magnetic semi-infinite three-dimensional electrodes. Based on Su–Schrieffer–Heeger (SSH) Hamiltonian and using a generalized Green’s function formalism, wecalculate the spin-dependent currents, the electronic transmission and tunnelling magnetoresistance (TMR). We found that the presence of a uniform distribution of the soliton centres along the molecular chain reduced the size of the band gap of {\it trans}-PA molecule. Moreover, a sublattice of the correlated solitons as binary clusters, which are randomly distributed along the chain, can induce extended electronic states in the band gap of the molecule. In this case, the band gap of the molecule is suppressed and at lower voltages, the TMR bandwidth is narrowed. The current–voltage characteristic then shows an ohmic-like behaviour.
Volume 86 Issue 4 April 2016 pp 777-781 Regular
Simulation of a quantum NOT gate for a single qutrit system
A three-level system based an a three-level atom interacting with a detuned cavity is considered. Because of the fact that the three-level atom defines a total normalized state composed of superposition of three different single-level states, it is assumed that such a system implements a qutrit. In order to achieve a quantum NOT gate for a single qutrit, the respective Schrödinger equation is solved numerically within a two-photon rotating wave approximation. For small values of one-photon detuning, there appear decoherence effects. Meanwhile, for large values of onephoton detuning, an ideal quantum NOT gate for a single qutrit is achieved. An expression for the execution time of the quantum NOT gate for a single qutrit as a function of the one-photon detuning is found.
Volume 86 Issue 4 April 2016 pp 893-900 Regular
Defect characterization of Ga$_4$Se$_3$S layered single crystals by thermoluminescence
Trapping centres in undoped Ga$_4$Se$_3$S single crystals grown by Bridgman method were characterized for the first time by thermoluminescence (TL) measurements carried out in the low temperature range of 15−300 K. After illuminating the sample with blue light (∼470 nm) at 15 K, TL glow curve exhibited one peak around 74 K when measured with a heating rate of 0.4 K/s.The results of the various analysis methods were in good agreement about the presence of one trapping centre with an activation energy of 27 meV. Analysis of curve fitting method indicated that mixed order of kinetics dominates the trapping process. Heating rate dependence and distribution of the traps associated with the observed TL peak were also studied. The shift of peak maximum temperature from 74 to 113 K with increasing rate from 0.4 to 1.2 K/s was revealed. Distribution of traps was investigated using an experimental technique based on cleaning the centres giving emission at lower temperatures. Activation energies of the levels were observed to be increasing from 27 to 40 meV by rising the stopping temperature from 15 to 36 K.
Volume 86 Issue 5 May 2016 pp 957-963 Regular
A novel approach for solving fractional Fisher equation using differential transform method
In the present paper, an analytic solution of nonlinear fractional Fisher equation is deduced with the help of the powerful differential transform method (DTM). To illustrate the method, two examples have been prepared. The method for this equation has led to an exact solution. The reliability, simplicity and cost-effectiveness of the method are confirmed by applying this method on different forms of functional equations.
Volume 86 Issue 6 June 2016 pp 1153-1160 Regular
ARNOUS A H MIRZAZADEH M ESLAMI M
In this paper, two integration schemes are employed to obtain solitons, singular periodic waves and other types of solutions of the Drinfel’d–Sokolov–Wilson equation. The two schemes studied in this paper are the Bäcklund transformation of Riccati equation and the trial function approach. The corresponding constraint conditions of the solutions are also given.
Volume 86 Issue 6 June 2016 pp 1195-1207 Regular
VENKATESH P R VENKATESAN A LAKSHMANAN M
The idea of synchronization can be explicitly demonstrated by both numerical and analytical means on a nonlinear electronic circuit. Also, we introduce a scheme to obtain various logic gate structures, using synchronization of chaotic systems. By a small change in the response parameter of unidirectionally coupled nonlinear systems, one is able to construct various logic behaviours by both numerical and analytical methods.
Volume 87 Issue 2 August 2016 Article ID 0028 Research Article
M E ZOMORRODIAN M HASHEMINIA S M ZABIHINPOUR A MIRJALILI
Inclusive momentum distributions of charged particles are measured in dijet events. Events were produced at the AMY detector with a centre of mass energy of 60 ${\rm GeV}$. Our results were compared, on the one hand to those obtained from other $e^+ e^-$, $ep$ as well as CDF data, and on the other hand to the perturbative QCD calculations carried out in the framework of the modified leading log approximation (MLLA) and assuming local parton--hadron duality (LPHD). A fit of the shape of the distributions yields $\scr Q_{eff} = 263 \pm 13 {\rm MeV}$ for the AMY data. In addition, a fit to the evolution of the peak position with dijet mass using all data from different experiments gives $\scr Q_{eff} = 226 \pm 18 {\rm MeV}$. Next, αs was extracted using the shape of the distribution at the Z0 scale, with a value of 0.118 \pm 0.013. This is consistent, within the statistical errors, with many accurate measurements. We conclude that it is the success of LPHD + MLLA that the extracted value of $\alpha_{s}$ is correct. Possible explanations for all these features will be presented in this paper.
Volume 87 Issue 5 November 2016 Article ID 0066 Regular
Space–time transformation for the propagator in de Broglie–Bohm theory
A linear space–time transformation proposed to calculate the propagator in the de Broglie–Bohm theory, is viewed as an expansion of the guiding wave function over the velocity space. It is shown that the quantum evolution is preserved in its semiclassical scheme through this change. The case of variable-frequencyharmonic oscillator is presented as an example.
Volume 87 Issue 5 November 2016 Article ID 0081 Regular
Analysis of tokamak plasma confinement modes using the fast Fourier transformation
S R MIRMOEINI A SALAR ELAHI M GHORANNEVISS
The Fourier analysis is a satisfactory technique for detecting plasma confinement modes in tokamaks. The confinement mode of tokamak plasma was analysed using the fast Fourier transformation (FFT). For this purpose, we used the data of Mirnov coils that is one of the identifying tools in the IR-T1 tokamak, with and without external field (electric biasing), and then compared it with each other. After the Fourier analysis of Mirnov coil data, the diagram of power spectrum density was depicted in different angles of Mirnov coils in the ‘presenceof external field’ as well as in the ‘absence of external field’. The power spectrum density (PSD) interprets the manner of power distribution of a signal with frequency. In this article, the number of plasma modes and the safety factor $q$ were obtained by using the mode number of $q = m/n$ ($m$ is the mode number). The maximum MHD activity was obtained in 30–35 kHz frequency, using the density of the energy spectrum. In addition, the number of different modes across 0–35 ms time was compared with each other in the presence and absence of theexternal field.
Volume 88 Issue 1 January 2017 Article ID 0015 Regular
M EGHBALI B FAROKHI M ESLAMIFAR
The nonlinear propagation of cylindrical and spherical dust-ion-acoustic (DIA) envelope solitary waves in unmagnetized dusty plasma consisting of dust particles with opposite polarity and non-extensive distribution of electron is investigated. By using the reductive perturbation method, the modified nonlinear Schrödinger (NLS) equation in cylindrical and spherical geometry is obtained. The modulational instability (MI) of DIA waves governed by the NLS equation is also presented. The effects of different ranges of the non-extensive parameter $q$ on the MI are studied. The growth rate of the MI is also given for different values of $q$. It is found that the basic features of the DIA waves are significantly modified by non-extensive electron distribution, polarity of the netdust-charge number density and non-planar geometry.
Volume 88 Issue 2 February 2017 Article ID 0021 Regular
In this work, we have obtained energy levels and charge radius for the $\beta$-stability line nucleus, in relativistic shell model. In this model, we considered a close shell for each nucleus containing double magicnumber and a single nucleon energy level. Here we have taken $^{41}$Ca with a single neutron in the $^{40}$Ca core as an illustrative example. Then we have selected the Eckart plus Hulthen potentials for interaction between the coreand the single nucleon. By using parametric Nikiforov–Uvarov (PNU) method, we have calculated the energy values and wave function. Finally, we have calculated the charge radius for 17O, $^{41}$Ca, $^{49}$Ca and $^{57}$Ni. Our results are in agreement with experimental values and hence this model can be applied for similar nuclei.
Volume 88 Issue 2 February 2017 Article ID 0036 Regular
M H MOGHTADER DINDARLU H TEHRANI M KAVOS H SAGHAFIFAR A MALEKI GH SOLOOKINEJAD M JABBARI
In this paper, an analytical model for temperature distribution of the side-pumped laser rod is extracted. This model can be used for side-pumped laser rods whose absorbed pump profile is a Gaussian profile. Then, it is validated by numerical results which exhibit a good agreement with the analytical results. Afterwards, by considering a general expression for super-Gaussian and top-hat profiles, and solving the heat equation, the influence of profile width and super-Gaussian exponent of the profile on temperature distribution are investigated.Consequently, the profile width turns out to have a greater influence on the temperature compared to the type of the profile.
Volume 88 Issue 3 March 2017 Article ID 0040 Research Article
Modified function projective combination synchronization of hyperchaotic systems
In this work, a novel combination synchronization scheme in which synchronization of a new combination hyperchaotic drive system formed by combining state variables of the original drive system with appropriate scaling factors with a response hyperchaotic system is considered. A self-combination system is constructed from hyperchaotic Lorenz system by combining state variables of the Lorenz system with appropriate scaling factors. Modified function projective synchronization between the newly constructed combination hyperchaotic Lorenz system and hyperchaotic Lu system is investigated using adaptive method. By Lyapunov stability theory, the adaptive control law and the parameter update law are derived to make the state of two systems as modified function projective synchronized. Numerical simulations are done to show the validity and effectiveness of the proposed synchronization scheme.
Volume 88 Issue 3 March 2017 Article ID 0048 Research Article
Z AMERIAN M K SALEM A SALAR ELAHI M GHORANNEVISS
Equilibrium reconstruction consists of identifying, from experimental measurements, a distribution of the plasma current density that satisfies the pressure balance constraint. Numerous methods exist to solve the Grad–Shafranov equation, describing the equilibrium of plasma confined by an axisymmetric magnetic field. In this paper, we have proposed a new numerical solution to the Grad–Shafranov equation (an axisymmetric,magnetic field transformed in cylindrical coordinates solved with the Chebyshev collocation method) when the source term (current density function) on the right-hand side is linear. The Chebyshev collocation method is a method for computing highly accurate numerical solutions of differential equations. We describe a circular crosssection of the tokamak and present numerical result of magnetic surfaces on the IR-T1 tokamak and then compare the results with an analytical solution.
Volume 88 Issue 3 March 2017 Article ID 0053 Research Article
A comparative analysis of the density distributions and the structure models of $^{9}$Li
In the present study, we have analysed the elastic scattering cross-section data of $^{9}$Li + $^{12}$C system at $E_{lab}$ = 540 MeV and $^{9}$Li + $^{208}$Pb system at $E_{c.m.}$ = 28.3 MeV for some cluster models and various density distributions of the $^{9}$Li nucleus. First, we have obtained five different density distributions of the $^{9}$Li nucleus to generate real potentials with the help of double-folding model. For these densities, we have calculated the elastic scattering angular distributions. Secondly, using a simple approach, we have investigated some cluster models of the $^{9}$Li nucleus consisting of $^{6}$He + $^{3}$H and $^{8}$Li + n systems. We have presented the comparison of elastic scattering angular distributions for each system with each other as well as with the experimental data. Finally, we have given the cross-section values obtained from the theoretical calculations for all the systems studied in this paper.
Volume 88 Issue 6 June 2017 Article ID 0081 Research Article
A rigorous theoretical investigation has been carried out on the propagation of nonplanar (cylindrical and spherical) dust-acoustic shock waves (DASHWs) in a collisionless four-component unmagnetized dusty plasmasystem containing massive, micron-sized, positively and negatively charged inertial dust grains along with $q$ (nonextensive) distributed electrons and ions. The well-known reductive perturbation technique has been used to derive the modified Burgers equation (which describes the shock wave properties) and its numerical solution. It has been observed that the effects of charged dust grains of opposite polarity, nonextensivity of electrons and ions, and different dusty plasma parameters have significantly modified the fundamental properties (viz., polarity, amplitude, width, etc.) of the shock waves. The properties of DASHWs in nonplanar geometry are found tobe significantly different from those in one-dimensional planar geometry. The findings of our results from this theoretical investigation may be useful in understanding the nonlinear features of localized electrostatic disturbancesin both space and laboratory dusty plasmas.
Volume 90 Issue 1 January 2018 Article ID 0001 Research Article
Entanglement of a nonlinear two two-level atoms interacting with deformed fields in Kerr medium
S ABDEL-KHALEK Y S EL-SAMAN M ABDEL-ATY
In this paper we investigate the entanglement dynamics between two two-level atoms interacting with two coherent fields in two spatially separated cavities which are filled with a Kerr-like medium. We examine the effect of nonlinear medium on the dynamical properties of entanglement and atomic occupation probabilities in the case of even and odd deformed coherent states. The results show that the deformed fields play important roles in the evolution of entanglement. Also, the results demonstrate that entanglement sudden death, sudden birth and long-distance can be controlled by the deformation and nonlinear parameters.
Volume 90 Issue 1 January 2018 Article ID 0005 Research Article
Anisotropic stars obeying Chaplygin equation of state
In this work we provide a framework for modelling compact stars in which the interior matter distribution obeys a generalised Chaplygin equation of state. The interior geometry of the stellar object is described by a spherically symmetric line element which is simultaneously co-moving and isotropic with the exterior space–time being vacuum. We are able to integrate the Einstein field equations and present closed form solutions which adequately describe compact strange star candidates such as 4U 1538-52, PSR J1614-2230, Vela X-1 and Cen X-3 (Gangopadhyay $\it{et al, Mon. Not. R. Astron. Soc.} \bf{431}$, 3216 (2013)).
Volume 90 Issue 2 February 2018 Article ID 0027 Research Article
Optical characteristics of a RF DBD plasma jet in various $\rm{Ar/O_{2}}$ mixtures
A FALAHAT A GANJOVI M TARAZ M N ROSTAMI RAVARI A SHAHEDI
In this paper, using the optical emission spectroscopy (OES) technique, the optical characteristics of a radiofrequency (RF) plasma jet are examined. The $\rm{Ar/O_2}$ mixture is taken as the operational gas and, the Ar percentage in the $\rm{Ar/O_2}$ mixture is varied from 70% to 95%. Using the optical emission spectrum analysis of the RF plasma jet, the excitation temperature is determined based on the Boltzmann plot method. The electron density in the plasma medium of the RF plasma jet is obtained by the Stark broadening of the hydrogen Balmer $H_\beta$. It is mostly seen that, the radiation intensity of Ar $\rm{4p\rightarrow 4s}$ transitions at higher argon contributions in $\rm{Ar/O_2}$ mixture is higher. It is found that, at higher Ar percentages, the emission intensities from atomic oxygen (O) are higher and, the line intensities from the argon atoms and ions including O atoms linearly increase. It is observed that the quenching of $\rm{Ar}^\ast$ with $\rm{O}_2$ results in higher O species with respect to $\rm{O}_2$ molecules. In addition, at higher percentages of Ar in the $\rm{Ar/O_2}$ mixture, while the excitation temperature is decreased, the electron density is increased.
Volume 90 Issue 3 March 2018 Article ID 0030 Research Article
Neutron energy measurement for practical applications
M V ROSHAN H SADEGHI M GHASABIAN A MAZANDARANI
Industrial demand for neutrons constrains careful energy measurements. Elastic scattering of monoenergetic $\alpha$-particles from neutron collision enables neutron energy measurement by calculating the amount of deviation from the position where collision takes place. The neutron numbers with specific energy is obtained by counting the number of $\alpha$-particles in the corresponding location on the charged particle detector. Monte Carlo simulation and COMSOL Multiphysics5.2 are used to account for one-to-one collision of neutrons with $\alpha$-particles.
Volume 90 Issue 3 March 2018 Article ID 0041 Research Article
B M ALI M AL-ABYAD U SEDDIK S U EL-KAMEESY F DITRÓI S TAKÁCS F TÁRKÁNYI
Excitation functions for α-induced reactions on natural vanadium were measured in the energy range up to 20 MeV. The stacked-foil activation technique was used. The experimental results were compared with the theoretical calculations using EMPIRE-3.1, EMPIRE-3.2.2 and TENDL 2015, and with earlier experimental results. Thick target yields were calculated for the production of $^{54}\rm{Mn}$ and for the associated impurity $^{52}\rm{Mn}$.
Volume 90 Issue 4 April 2018 Article ID 0044 Research Article
M MALLIGAVATHY S IYYAPUSHPAM S T NISHANTHI D PATHINETTAM PADIYAN
$TiO_{2}$ nanoparticles were synthesised by hydrothermal method. The degree of crystallinity and phase purity were confirmed from the Raman spectra and X-ray diffraction. By increasing the hydrothermal temperature,crystallinity and AC conductivity of the $TiO_{2}$ nanoparticles increase. Nitrogen adsorption–desorption measurements confirmed that the samples were mesoporous with an average pore diameter of 4.4–7.45 nm. Photocatalytic activity of $TiO_{2}$ nanoparticles was evaluated and the sample hydrothermally treated at 160$^\circ$C has the highest photocatalytic activity. In gas sensing measurements, sensitivity increases as a function of concentration and the response to ethanol vapour was better compared to other gases for the sample synthesised at 160$^\circ$C.
Volume 90 Issue 4 April 2018 Article ID 0048 Research Article
Volterra integral equation-factorisation method and nucleus–nucleus elastic scattering
An approximate solution for the nuclear Hulthén plus atomic Hulthén potentials is constructed by solving the associated Volterra integral equation by series substitution method. Within the framework of supersymmetry-inspired factorisation method, this solution is exploited to construct higher partial wave interactions. The merit of our approach is examined by computing elastic scattering phases of the $\alpha−\alpha$ system by the judicious use of phase function method. Reasonable agreements in phase shifts are obtained with standard data.
Volume 90 Issue 5 May 2018 Article ID 0057 Research Article
Exciton binding energy in a pyramidal quantum dot
The effects of spatially dependent effective mass, non-parabolicity of the conduction band and dielectric screening function on exciton binding energy in a pyramid-shaped quantum dot of GaAs have been investigatedby variational method as a function of base width of the pyramid. We have assumed that the pyramid has a square base with area $a \times a$ and height of the pyramid $H = a/2$. The trial wave function of the exciton has been chosen according to the even mirror boundary condition, i.e. the wave function of the exciton at the boundary could be non-zero. The results show that (i) the non-parabolicity of the conduction band affects the light hole (lh) and heavy hole (hh) excitons to be more bound than that with parabolicity of the conduction band, (ii) the dielectric screening function (DSF) affects the lh and hh excitons to be more bound than that without the DSF and (iii) the spatially dependent effective mass (SDEM) affects the lh and hh excitons to be less bound than that without the SDEM. The combined effects of DSF and SDEM on exciton binding energy have also been calculated. The results are compared with those available in the literature.
Volume 90 Issue 6 June 2018 Article ID 0080 Research Article
A theoretical model is described here for studying the effect of temperature on nanomaterials. The thermodynamic equation of state (EoS) proposed by Goyal and Gupta in
Volume 91 Issue 1 July 2018 Article ID 0004 Research Article
P MEGAVARNA EZHILARASU M INBAVALLI K MURALI K THAMILMARAN
In this paper, we report the dynamical transitions to strange non-chaotic attractors in a quasiperiodically forced state controlled-cellular neural network (SC-CNN) based MLC circuit via two different mechanisms, namely the Heagy–Hammel route and the gradual fractalisation route. These transitions were observed through numerical simulations and hardware experiments and confirmed using statistical tools, such as maximal Lyapunov exponent spectrum and its variance and singular continuous spectral analysis. We find that there is a remarkable agreement of the results from both numerical simulations as well as from hardware experiments.
Volume 91 Issue 1 July 2018 Article ID 0014 Research Article
Aspects of improved heat conduction relation and chemical processes in 3D Carreau fluid flow
M KHAN M IRFAN W A KHAN M AYAZ
This article communicates the numerical consideration of 3D Carreau liquid flow under the impact of chemical responses over a stretched surface. Moreover, the heat transfer exploration is carried out with a view to improve the heat flux relation. This phenomenon is established upon the theory of Cattaneo–Christov heat flux relation that contributes by the thermal relaxation. On exploitation of an appropriate transformation a system of nonlinear ODEs is attained and then elucidated numerically by means of bvp4c scheme. The descriptions of temperature and concentration fields equivalent to the frequent somatic parameters are graphically scrutinised.Our analysis carries that the concentration of the Carreau liquid displays similar tendency and decline as theheterogeneous–homogeneous reaction parameters ($k_{2}, k_{1}$) augment. Furthermore, it is notable that for shear thinning ($n$ & lt; 1) liquid, the influence of local Weissenberg numbers ($We_{1}, We_{2}$) are absolutely conflicting compared with the instance of shear thickening ($n$ & gt; 1) liquid. Additionally, validation of numerical results is done via benchmarking with previously stated limiting cases with two different schemes namely, homotopy analysis method (HAM) and bvp4c scheme. These comparisons initiate a superb correspondence with these outcomes.
Volume 91 Issue 5 November 2018 Article ID 0063 Research Article
W A KHAN A S ALSHOMRANI A K ALZAHRANI M KHAN M IRFAN
The pursuit of superior working liquids for heat/mass transfer mechanisms in engineering is on the rise, not only to maximise revenue but also to accommodate heat dissipation or chemical separation under extreme conditions. The addition of a small amount of nanoparticle, i.e. a product called nanofluid, has been initiated over the last decade. In this paper, we present a comprehensive study of unsteady three-dimensional (3D) flow of the Eyring–Powell nanofluid under convective and nanoparticles mass flux conditions. The effects of constructive/destructivechemical reactions and nonlinear thermal radiation are also considered in the Eyring–Powell nanofluid model. Additionally, suitable transformations are utilised to obtain coupled ordinary differential equations (ODEs) from the system of partial differential equations (PDEs) and the numerical solution of the system of the coupled ODEs is obtained by means of the bvp4c scheme. The obtained numerical data are plotted for the temperature and concentration profiles of nanofluids for various and converging values of physical parameters. Our findings demonstrate that the temperature of the Eyring–Powell nanofluid fall-off by changing the heat sink parameter. Furthermore, it is perceived from the sketches that the concentration of Eyring–Powell magneto-nanofluid decays at higher values of chemical reaction parameter.
Volume 91 Issue 5 November 2018 Article ID 0066 Research Article
In this work, a comparative study is made on photonic crystal fibre (PCF) with circular and elliptical air holes in square lattice for supercontinuum generation. Using finite-element method analysis in COMSOL MULTIPHYSICS 4.3b software, numerical investigation on optical parameters such as dispersion, confinement loss, birefringence and nonlinearity has been carried out. Change in each optical parameter is observed by varying the radius of the circular air hole and the radius of the major axis of the elliptical air hole. The supercontinuum generation for the proposed PCF is also numerically simulated and studied under different power and pulse width.
Volume 91 Issue 6 December 2018 Article ID 0074 Research Article
B AL-NASHY M ABDULLAH ALI GEHAD AL-SHATRAVI AMIN HABBEB AL-KHURSAN
This work discusses lasing without inversion in Y-scheme in a double quantum dot nanostructure. This new type of lasing, which results from the quantum interference of spontaneous emission components, was not discussed earlier in quantum dot nanostructures. It is found that both pumping and cycling fields control the laser emission. The decrease of the cycling detuning increases the possibility of lasing. Probe detuning controls the width of the absorption bath (electromagnetic-induced transparency window) of this structure. This phenomenon canhave an interesting application for developing sources of coherent radiation in a region of electromagnetic spectrum where the implementation of traditional laser schemes is difficult.
Volume 91 Issue 6 December 2018 Article ID 0076 Research Article
Aharonov–Bohm effect in the ghost interference
M EL ATIKI M BENDAHANE A KASSOU-OU-ALI
In the ghost interference experiment, a pair of entangled particles is sent in the opposite directions; one of the particles passes through a Young double-slit while the other continues its way freely. It turns out that the particles passing through the slits do not show any first-order interference while those propagating freely constitute an interference pattern when they are detected in coincidence with those which pass through the slits and detectedat a fixed position. In this work, we consider that the particles are charged and the effect of a confined magnetic field is analysed between the slits in an Aharonov–Bohm configuration.
Volume 91 Issue 6 December 2018 Article ID 0087 Research Article
Shape, size and phonon scattering effect on the thermal conductivity of nanostructures
A phenomological model is described here to study the effect of size, shape and phonon scattering on the thermal conductivity of nanostructures. Using the classical model proposed by Guisbiers
Volume 92 Issue 2 February 2019 Article ID 0015 Research Article
One-dimensional nuclear design analyses of the SST-2
CHANDAN DANANI DEEPAK AGGARWAL H L SWAMI VINAY MENON RITESH SRIVATSAVA AASHOO SHARMA DEEPTI SHARMA M HIMA BINDU JYOTI AGRAWAL M MANOAH STEPHEN NAVEEN RASTOGI PRAMIT DUTTA SOMESWAR DUTTA UPENDRA PRASAD M WARRIER R SRINIVASAN
Steady State Tokamak-2 (SST-2) will be an intermediate fusion machine before Indian DEMOnstration power reactor (DEMO) development to realise the reactor technologies. It is designed for fusion gain Q = 5 andfusion power in the range of 100–300 MW. Nuclear design analyses of SST-2 machine have been carried out to support the conceptual design work. Analyses have been carried out for two breeding blanket concepts: Indian lead–lithium ceramic breeder (LLCB) and helium-cooled ceramic breeder (HCCB). The analyses assess the tritium production and radiation shielding capability of the machine referring to the engineering design parameters. In this study, one-dimensional radiation transport calculations have been performed to assess the SST-2 nuclear responses for 1 full power year (FPY) operation. Nuclear responses such as tritium breeding ratio (TBR), various radiation loads to toroidal field (TF) coil have been calculated to obtain the radial build-up of SST-2 capable of breeding tritium and satisfying the shielding requirements. The assessment has been made using the ANISEN code andFENDL 2.1 cross-section library. It is observed that the TBRs with LLCB and HCCB blankets are 0.85 and 0.94, respectively. Shielding calculations confirm that the radial build is sufficient to protect the superconducting TF coils for 1 FPY.
Volume 92 Issue 2 February 2019 Article ID 0016 Research Article
W A KHAN M ALI F SULTAN M SHAHZAD M KHAN M IRFAN
A simple relation of chemical processes for three-dimensional flow of a cross magnetofluid over bidirectional stretched surface is constructed. The impact of convective heat transport in the manifestation of non-linear thermal radiation and features of heat source–sink are also considered for heat transfer mechanism.Furthermore, in this research paper, the innovative relation between heterogeneous and homogeneous responses with equivalent diffusivities for reactant and autocatalysis is exploited. Apposite alterations are guaranteed to obtain ordinary differential equations (ODEs) with high nonlinearity. Numerically, the bvp4c technique is exploited to the interpret the structure of ODEs. Portrayals of temperature and concentration for cross liquid equivalent to abundant somatic parameters are presented graphically as well as in tabular form. Our results reveal that the temperature of the cross fluid decreases with fluctuation in the heat sink parameter. Furthermore, it is perceived from the figuresthat the concentration of the cross fluid reduces for higher values of chemical reaction parameters.
Volume 92 Issue 2 February 2019 Article ID 0017 Research Article
Heat transfer enhancement for Maxwell nanofluid flow subject to convective heat transport
Nanoliquids possess remarkable features that have fascinated numerous researchers because of their utilisation in nanoscience and nanotechnology. A mathematical relation for the two-dimensional flow of Maxwell nanoliquid over a stretching cylinder is established. Buongiorno’s relation is considered here to visualise the impact of Brownian moment and thermophoresis mechanisms on Maxwell liquid. The convective heat transport is deliberated for heat transfer mechanisms. Transformation procedure yields nonlinear differential system which is then computed through the homotopic approach. The results obtained are studied in detail in relation to somatic parameters. It is notable that the velocity of Maxwell liquid shows conflicting behaviour for curvature parameter $\alpha$ and Deborah number $\beta$. Moreover, the liquid temperature increases for increased values of Brownian motion $N_{b}$ and thermophoresis parameter $N_{t}$ . Additionally, the authentication of numerical consequences is prepared via benchmarking with formerly identified restrictive circumstances and we initiate a splendid communication with these results.
Volume 92 Issue 2 February 2019 Article ID 0021 Research Article
F SULTAN W A KHAN M ALI M SHAHZAD M IRFAN M KHAN
The current review proclaims the forced convective flow and heat–mass transfer characteristics of cross nanofluid past a bidirectional stretched surface. The most significant aim of the current review is to incorporatethe features of Buongiorno relation, activation energy, nonlinear thermal radiation and heat sink–source for a three-dimensional flow of the cross fluid. Appropriate transformations are employed to transform the modelledpartial differential equations (PDEs) of momentum, temperature and concentration into coupled nonlinear ordinary differential equations (ODEs). The governing boundary value problem is numerically integrated with the help of bvp4c scheme. The obtained numerical data are plotted for the temperature and concentration profiles of nanofluid for various converging values of physical parameters. The dependence of increasing thermophysical parameters on temperature and concentration profiles of the cross nanofluid is graphically demonstrated. Furthermore, detailedstudy reveals that the concentration of the cross nanofluid decreases for increasing values of Brownian motion parameter. It is also perceived from the sketches that the concentration of the cross nanofluid decreases for higher values of chemical reaction parameter. The validity of the achieved numerical outcomes is ensured by making a comparison with the existing work as special cases.
Volume 92 Issue 4 April 2019 Article ID 0050 Research Article
Collisional absorption of laser light in an under-dense plasma is studied by particle-in-cell (PIC) simulation with Monte Carlo binary Coulomb collisions between charge particles. For a given plasma thickness of a few times the wavelength of 800 nm laser, fractional absorption ($\alpha$) of the laser light due to Coulomb collisions (mainly between electrons and ions) is calculated at different electron temperature $T_{e}$ with a total velocity $v = (v^{2}_{th} + v^{2}_{0}/2)^{1/2}$ dependent Coulomb logarithm ln $\Lambda(v)$, where $v_{th}$ and $v_{0}$ are thermal and ponderomotive velocity of an electron. In the low-temperature regime ($Te \lesssim 15 eV$), it is found that $\alpha$ increases with increasing laser intensity $I_{0}$ up to a maximum corresponding to an intensity $I_{c}$, and then it drops (approximately) obeying the conventional scaling of $\alpha \varpropto I^{−3/2}_{0}$ when $I_{0}$ > $I_{c}$. Such a non-conventional increase of $\alpha$ with $I_{0}$ in the low intensity regime was demonstrated earlier in experiments, and recently explained by classical and quantum models [
Volume 92 Issue 4 April 2019 Article ID 0064 Research Article
C-matrix and invariants in chemical kinetics: A mathematical concept
M SHAHZAD F SULTAN I HAQ M ALI W A KHAN
To treat a realistic chemical system, such as a liquid phase dehydrogenation reaction, a chemical scheme, which describes the chemical kinetics in terms of the small number of reaction progress variables is needed. Based onthe matrix algebra, we analyse the key components, elements and reactions in the mechanism, C-matrix. Reduction techniques exploit the time-scale separation into fast and slow modes by computing the dimension reduced model via the elimination of fast mode subjecting them to the slow one. The two-step reversible reaction mechanism is considered for model reduction and to simplify the complexity of reaction mechanisms. They give a meaningful picture, but for maximum clarity, the phase flow of the solution trajectories near the equilibrium point is exploited. The Lyapunov function is applied for the stability analysis. To describe the physical behaviour of the reaction mechanism, graphical results are measured while refinement of the initial approximation is tabulated at the end.
Volume 92 Issue 5 May 2019 Article ID 0071 Research Article
Numerical solution of regularised long ocean waves using periodised scaling functions
M BAKHODAY-PASKYABI A VALINEJAD H DEILAMI AZODI
In this paper, a numerical technique for solving the regularised long wave equation (RLW) is presented using a wavelet Galerkin (WG) method in space and a fourth-order Runge–Kutta (RK) technique in time.We study the convergence analysis of the obtained numerical solutions and investigate the results for the motions of doubleand single solitary waves, undular bores and conservation properties of mass, energy and momentum in order to verify the applicability and performance of the proposed method. Simulation results are further compared with the known analytical solutions and some previous published numerical results. It is concluded that the present method remarkably improves the accuracy of the Galerkin-based methods for numerically solving a large class of nonlinear and weakly dispersive ocean waves.
Volume 93 Issue 1 July 2019 Article ID 0014 Research Article
In this work, the radiation shielding properties of various natural stones, such as granite, basalt, andesite and tuff, were determined by using Monte-Carlo simulations performed with the Geant4 model of a high-purity germanium (HPGe) detector.Mass attenuation coefficients were calculated for $\gamma$ -ray energies of 80.9, 140.5, 356.5, 661.6, 1173.2 and 1332.5 keV and for the sample thicknesses between 1 and 7 cm. The results of this study indicate that the stone samples have lower mass attenuation values varying in the range from −28.8% to −3.7% compared to lead. Among the measured stone samples, the mass attenuation values of tuff stone are closest to lead (above661.6 keV).
Volume 93 Issue 1 July 2019 Article ID 0016 Research Article
The Weyl equation under an external electromagnetic field in the cosmic string space–time
M HOSSEINI H HASSANABADI S HASSANABADI
In this paper we have considered a massless spinor Dirac particle in the presence of an external electromagnetic field in the cosmic string space–time. To study the Weyl equation in the cosmic string framework using the general definition of Laplacian in the curved space, elements of covariant derivative have been constructed and the Weyl equation has been rewritten in the considered framework. Then we have obtained the equation ofenergy eigenvalues by using the Nikiforov–Uvarov (NU) method. The wave function has been obtained in terms of Laguerre polynomials. An important result obtained is that the degeneracy of the Minkowski space spectral is broken in the transition from Minkowski to cosmic string space.
Volume 93 Issue 3 September 2019 Article ID 0033 Research Article
On physical limitations of mathematical constructions used in mathematical models
Physical limitations of mathematical constructions are discussed, which should be taken into account in developing or modifying mathematical models. We begin with consideration of the method of describing physical objects using numbers and restrictions followed from this method. Next, we formulate some general recommendations concerning procedures for modifying mathematical models. Since models of physical phenomena are considered, it is natural to provide a physical interpretation for each stage of the model development. Unfortunately, some of transformations used are treated as purely technical tricks, and therefore the question of the physical meaning is not raised in such cases. The lack of physical meaning of some mathematical procedures does not make them unambiguously unacceptable. However, this marks out the place that requires a reasonable interpretation because the final result should possess the physical meaning. Finally, we discuss the issues related to the dimensionality of the space of places of a model. The above-mentioned physical limitations often are left without necessary attention. Sometimes this leads to various undesirable consequences, which may include excessive complication of the problem, an implicit substitution of the declared problem with another one or, finally, the absence of solution of the formulated problem.
Volume 93 Issue 3 September 2019 Article ID 0040 Research Article
S MUHAMMAD G ALI S I A SHAH M IRFAN W A KHAN M ALI F SULTAN
This research demonstrates the diverse characteristics of the cross fluid in the presence of Lorentz’s forces. Moreover, this work reviews the characteristics of variable diffusivity and variable conductivity. Mathematical modelling of the presented physical model is carried out in the Cartesian coordinate system and the formulated system of partial differential equations (PDEs) is simplified in ordinary differential equations (ODEs). Numerical algorithm leads to solution computations. Velocity, temperature and concentration are numerically analysed for the cross fluid. Outcomes of the current physical model are presented through graphical data and in tabular form. It is noted that variable conductivity and variable diffusivity significantly affect heat–mass transport mechanisms. Furthermore, graphical analysis reveals that the concentration of the cross nanofluid increase for increased values of variable diffusivity. Furthermore, this research reveals that concentration distribution is a reducing function of chemical reaction parameters.
Volume 93 Issue 5 November 2019 Article ID 0072 Research Article
A microscopic study of elastic scattering of carbon isotopes from different target nuclei at various incident energies is presented by using density distributions derived for $^{10–14,16}\rm{C}$ nuclei using relativistic mean field (RMF) theory. To obtain the real part of the optical potential, the double folding model is used.Woods–Saxon potential is used for the imaginary part. The theoretical results are discussed and compared with each other as well as with the experimental data. It is seen that the agreement between theoretical results and experimental data is very good. Also, new global equations for the imaginary potentials of the $^{10–14,16}\rm{C}$ nuclei are derived from the results of the theoretical analysis.
Current Issue
Volume 93 | Issue 5
November 2019
Click here for Editorial Note on CAP Mode
© 2017-2019 Indian Academy of Sciences, Bengaluru.