[en] Anil complexes of uranium (VI) of the type UO₂(CH₃COO)(SB) (where SB represents the anions of the Schiff bases derived from salicylaldehyde and arylamines) have been synthesized in almost quantitative yields by the reaction of uranyl acetate with the Schiff base (HSB) in 1:1 molar ratio. Conductance, electron and IR spectral studies have been carried out to charaterize the complexes. The complexes are assigned octahedral structures in which acetate group acts as a bidentate ligand. (auth.)

[en] The paper outlines the problems of designing the top shield structure of fast reactor, which will essentially consist of two rotating plugs with eccentric housings in each. The plugs will contain shielding materials. The plugs should withstand an internal test pressure of 1 bar. At normal working conditions, the plug bottom will be around 400⁰C whereas the top will be maintained at 40⁰C. Considering each rotating plug as a pressure vessel, it has a unique structure. Three horizontal plates and four vertical shells form two chambers. The plates have an eccentric hole each. Vertical tubes traverse the height of the plug structure and are fixed at the two ends to the plates. The available literature does not provide means to analyse the stresses in the components; therefore simulated studies will be needed to design such structures. (author)

[en] X-band (∝9.4 GHz) microwave-absorption measurements have been performed on single and polycrystals of the high-Tc superconducting material Bi₂Sr₂CaCu₂O_8+δ in the temperature range 4.2-100 K. The microwave absorption indicated the onset of the transition to the superconducting phase at 89 K, the transition to the superconducting phase being complete at 84 K. Low-field microwave absorptions were recorded at temperatures below 89 K. These absorptions exhibited large anisotropies with respect to the relative orientations of the microwave and external magnetic fields; as well, they exhibited dependence on the orientation of the c-axis of the crystals relative to the external and microwave fields. The magnetic hysteresis, as well as the effect of field cooling on microwave absorption were also investigated and the equilibrium fields, B_eq, were determined. In addition, the value of the lower critical field B^{perpendicularto}_c1 has been estimated. It is concluded that, although some features of microwave absorptions are common to the various samples investigated, there exist some significant differences in the natures of the microwave absorption by the samples; an explanation based on the existence of isolated superconducting grains and defects has been provided. (orig.)

[en] Annealing of divacancies in 8 MeV proton-irradiated silicon was investigated using electron paramagnetic resonance (EPR). This paper presents the results for annealing at 160 deg. C for up to 600 min and for one sample annealed at 250 deg. C. The EPR signal shows a clear evolution with annealing time for annealing at 160 deg. C. Annealing for 40 min at 250 deg. C, yields almost the same EPR signal as for a 600 min anneal at 160 deg. C, but with a lowered intensity. In the light of previous results, the EPR behaviour substantiate the presence of two distinct annealing stages for defects in proton-irradiated silicon

[en] X-band EPR linewidths of Gd³⁺-doped LiYb_xY_1-xF₄ crystals (0.0 ≤ x ≤ 1.0) are measured in the temperature range 4.2 to 290 K. It is found that the peak-to-peak linewidth of the first derivative lineshape (ΔH_pp) can be fitted to T^-n (T = temperature), where generally n < 2, in the various temperature regions, for all the crystals. ΔH_pp is, in general, found to be quite sensitive to the mole fraction (x) of Yb³⁺ ions. The Yb³⁺ spin-lattice relaxation times (τ₁^') are estimated in these crystals, using the theories of Anderson-Weiss and Mitsuma, taking into account the fact that there are present two different kinds of paramagnetic ions, Gd³⁺ and Yb³⁺. It is concluded that the dipole-dipole interactions play an important role in the spin-lattice relaxation of Yb³⁺ ions. (author)

[en] Color transitions internal to diquark and antidiquark for baryonium in the L = 0 state are explicitly considered. Significant color mixing is found, raising the possibility that baryonium states do not exist

[en] X-band room temperature EPR spectra have been recorded for Mn²⁺ ion doping unannealed (La₂O₃)sub(0.95)(CeO₂)sub (0.05) host crystal. The data are analysed using a rigorous least-squares fitting procedure in which a large number of lines characterized by ΔM = +- 1, Δm = 0 transition, obtained for several orientations of the static magnetic field, are simultaneously fitted. Combined with the knowledge of the absolute sign of the hyperfine interaction parameter A, the hyperfine Hamiltonian parameters A,B,Q as reported in this paper, are given with their correct signs. The information on the linewidths is used to deduce the deviation of the crystal-field axes of different Mn²⁺ ions from the c axis; on the basis of the model proposed here these deviations are found to be between 0 and 10⁰. (author)

[en] Room-temperature X-band EPR data for Gd³⁺-doped isostructural rare-earth trichloride hexahydrates are analyzed using a rigorous least-squares-fitting procedure. Discussion of the three forms of spin Hamiltonian corresponding to the orientations of the two-fold monoclinic symmetry axis C₂ parallel to the magnetic axes X, Y, and Z is provided. It is found that for, C₂ parallel Y, a significantly lower value of χ², representing the goodness of fit, is obtained. A discussion of the determination of degree of monoclinicity, as revealed by the spin Hamiltonian parameters, is provided. Systematics of the spin Hamiltonian parameters b₂⁰ and b₂², as functions of the host-ion radius, are also studied. (author)

[en] A formula IFOM (improved figure of merit) is suggested which can be used for examining the goodness-of-fit of all types of spectral peaks - wide or narrow, strong or weak (relative to the associated background). This formula has been successfully applied to a large number of test cases and has been found to work succesfully in all these cases. A few examples, representative of different situations, are provided for illustrative purposes. (orig.)

[en] An analytic formula is suggested which can be used for examining the goodness-of-fits of all types of spectral peaks - wide or narrow, strong or weak (relative to the associated background) - as well as for evaluating the parameters (peak heights, widths, etc) in least-squares fitting procedures. This formula has been applied to a large number of test cases and has been found to work successfully in all the cases. The output values are such that the goodness-of-fits are easily scanned. (orig.)