Volume 4, Issue 5
May 1975, pages 199-245
pp 199-212 May 1975 Solids
A study of erbium, thulium and other rare earth ethyl sulphates
The available sets of crystal field parameters for erbium and thulium ethyl sulphates are used to calculate the Stark levels,g-values, Schottky specific heat, magnetic anisotropy, hyperfine interaction parameters and low temperature specific heat of these compounds. A comparison of these calculations with experimental data shows that one of these sets can be taken to be optimum within the accuracy of various measurements. These parameters along with the already optimised ones for other ethyl sulphates are discussed in the frameworks of electrostatic, angular overlap and superposition models for the crystalline fields. The antibonding energy parameter and ionicity are found to be different for light and heavy compounds and almost constant in either half of the series.
pp 213-217 May 1975 Solids
Elastic constants of sodium chlorate from 77 K to 350 K
K R Srinivasan E S R Gopal J Ramakrishnan S Krishnan
The elastic constantsC_{11},C_{12} andC_{44} of sodium chlorate single crystal have been evaluated using 10 MHz ultrasonic pulse echo superposition technique. The values areC_{11}=4.90,C_{12}=1.39,C_{44}=1.17 (× 10^{10}N/m^{2}) at 298 K and 6.15, 2.16, 1.32 (×10^{10}N/m^{2}) at 77 K. The data agree well with the values measured earlier up to 223 K. Brief mention is also made of the low temperature bonding problems in these soft crystals.
pp 218-221 May 1975 Nuclear And Particle Physics
K-capture probability in the decay of^{139}Ce(137.5d)
The K-capture probability (P_{K}) in the decay of^{139}Ce (137.5d) has been determined from the analysis of the K x-ray gamma ray sum-peak observed with a Ge (Li) x-ray detector. Furthermore,P_{K} is estimated independently from the measurement of the K x-ray intensity in the decay, using the known conversion coefficients of the 165.8 keV transition. Using the weighted average ofP_{K} measured as above, the mass difference between^{139}Ce and^{139}La is found to be 273_{−13}^{+21} keV.
pp 222-228 May 1975 Nuclear And Particle Physics
Effect of gluons on neutral-current interactions in deep inelastic neutrino scattering
The contribution of neutral spin-1 gluons to the deep inelastic neutral-current processesv(v)+N→v(v)+ hadrons is worked out in the parton model. Such a contribution violates Bjorken scaling strongly.
pp 229-241 May 1975 Experimental Techniques And Instrumentation
Characteristics of a high frequency ion source used in a low-energy accelerator
Mohamed E Abdelaziz Mohamed A Eid Fatma Abdelsalam
This work presents the characteristics of a high frequency ion source operating on a low energy, 150 keV accelerator. The latter is to be used as a neutron generator and its design is based on a theoretical analysis which shows that if the axial potential in an electrostatic electrode system is made to increase with four thirds the power of axial distance, inward electric forces will compensate space charge forces tending to blow up the beam. This results in a simplified acceleration tube much shorter and of higher gradient than the conventional acceleration columns. The ion source itself is an ordinary type using axial extraction of the beam, and its main properties investigated are the beam current and beam quality (or emittance). Dependence of the two on different parameters is investigated in a series of tests.
pp 242-245 May 1975 Mathematical Physics
Hölder’s inequality for matrices
We prove that for arbitraryn×n matricesA_{1},A_{2},…,A_{m} and for positive real numbersp_{1},p_{2},…,p_{m} withp_{1}^{−1}+p_{2}^{−1}+…+p_{m}^{/−1}=1, the inequality$$|Tr(A_1 A_2 ...A_m )^2 |< \mathop {II}\limits_{k = 1}^m [Tr(A_k^\dag A_k )^{p_k } ]P_k^{ - 1} $$ holds.
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