We have studied the hysteresis loops of RBa₂Cu₃O₇ (R=Gd, Ho and Y) and detected anomalies in some of them. The observed anomalies support a recent prediction by Ravi Kumar and Chaddah based on an extension of Bean’s model. The anomalies indicate lowH_c1 values and we have confirmed this by studying the onset of low-field hysteresis in less than 10 Oe at 77 K for these highT_c superconductors.

We obtain the superconformal transformation laws of theN=4 supersymmetric Yang-Mills theory and explicitly demonstrate the closure of the algebra.

Configuration assignments are derived for the observed energy levels in the odd-odd deformed nucleus¹⁷⁰Lu₉₉ based on the calculations of the two-particle band head energies for a zero range residual interaction, the beta-feeding characteristics, and the observed features for similar bands in the neighbouring nuclei. In particular, specific assignments are given for theJ^π=1⁺ levels at 198.4 keV, 349.0 keV and 785.5 keV. The ambiguities with respect to the assignments for theK^π=3⁻ bands are discussed. A new isomer withJ^π=7⁺ and half-life of several seconds is predicted around (225±25) keV and experiments are suggested to identify it.

A study of effective implementation of threshold activation technique for neutron spectral analysis in the environment of an alpha-cyclotron target is presented. The activation data are analysed using LOUHI-82 code. Optimal choices of the regularization parameters of the code are studied and discussed. Energy distribution of neutrons emitted from thick targets of Be, C and Ta irradiated by 40–45 MeV alphas is discussed.

Two features of³²S(d, p)³³S reaction to the continuum, the parallelism between the excitation function of the energy differential stripping cross-section d²σ/dΘdE and the total neutron³²S elastic scattering cross-section and the dependence of the ratio (d²σ/dΘdE)/σ_tot(n, n) on the transferred angular momentuml are explained by a model in which neutron stripping to the resonant states is essentially determined by the off-energy shell total neutron-target cross-section. At low excitation energies of the resonance the off-shell behaviour of the neutron scattering amplitude is very strong which leads to a big enhancement of the stripping cross-section relative to the total neutron-target cross-section. The model provides a good description of the measured (d, p) to (n, n) cross-section ratio corresponding tol>0 resonance. However it may not be appropriate for performing the calculations fors-wave resonances.

The infrared and Raman spectra of MoO₃·2H₂O are recorded and analysed on the basis of vibrations due to MoO₆ octahedra and H₂O molecules. Considerable changes in the frequencies of the octahedra have been observed due to strong distortion in the octahedral arrangement. The inactivev₆ vibration of O_h symmetry became active in the Raman spectrum. Co-ordinated (aquated) and hydrated (interlayer) water molecules give rise to different frequencies.

Photoacoustic spectra of rhodamine 110, rhodamine 6 G, rhodamine B, rhodamine 101 and coumarin 102 laser dyes have been recorded at room temperature of 25°C in the spectral range of 350–750 nm. These samples were taken in powder as well as in solution forms. For this purpose the closed and the open photoacoustic cells have been used. It is hoped the present study would be useful for characterization of these dyes.

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.