Investigation of phonon anomalies in intermediate valence compounds SmS and Sm0·65Y0·25S

Phonon anomalies in two intermediate valence compounds (IVC), SmS and Sm_0·75Y_0·25S have been investigated using breathing shell model (BSM). The BSM includes breathing motion of electron shells of the rare earth atom due tof−d hybridization. The phonon dispersion curves of IVC, calculated from the present model, agree well with the measured data. One-phonon density of states calculated from the present model compares well with the Raman spectra.     

Static,anharmonic and phonon properties of ND4I

A detailed investigation of the phonon dispersion and static and anharmonic properties has been carried out for ND₄I using an extended three-body force shell model (ETSM) developed by Singh and Chandra. The ETSM results for phonon dispersion show better agreement with the experimental data than those obtained from the deformation dipole and rigid shell models. Calculated values have also been obtained for some other properties.     

On hydromagnetic turbulent shear flow between moving parallel planes

Hydromagnetic turbulent shear flow of viscous, incompressible, electrically conducting fluid between two infinite uniformly porous moving parallel planes in the presence of axial and transverse magnetic field has been studied by the semi-empirical method. The expressions for the mean distributions for velocity and magnetic field for turbulent shear flow have been obtained for both the cases. As particular cases, the results have been obtained if the planes are fixed. The solutions obtained when the magnetic field is axial have been shown graphically for turbulent and laminar flows.     

Structural and functional analogue of the active site of polysulfide reductase from Wolinella succinogenes

Synthesis of [PPh4]2[Mo(SPh)2(S2C2(CN)2)2] (2) from [PPh4]2[MoO(S2C2(CN)2)2] (1) has been achieved to mimic the postulated [Mo(S)6] core of polysulfide reductase with two thiolates and two bis(ene-dithiolate) ligands. Compound 2 reacts with polysulfide to yield H2S, modeling the function of polysulfide reductase. The facile conversion of 2 back to 1 in moist solvent suggests that the interconversion of the [MoIV = O] and [MoIV - X] (X = O-Ser, S-Cys, Se-Cys) moieties might occur in the DMSO reductase class of enzymes under appropriate hydrophobic/hydrophilic conditions.     

Gold nanosheets via reduction of aqueous chloroaurate ions by anthracene anions bound to a liquid-liquid interface

Anthracene anions bound to a liquid-liquid interface and charged by photochemically reduced Keggin ions when exposed to aqueous chloroaurate ions result in the formation of high concentration of thin, gold nanosheets at the interface.     

A Novel Implementation Technique of Conical Scan Radar Using A Programmable Phased Array

In radar, planar phased array antenna plays vital role in electronic scanning in the azimuth and elevation direction to the horizon. In most operations using planar phased array both the coordinates of azimuth and elevation, are steered electronically. In this paper a conceptual schematic of a phased array antenna with programmable time delay units has been presented. It is shown that by suitably exploiting the time delay matrix one can have electronic beam rotation around the target axis as required in conical scan. Thus both the elevation and azimuth motors in conical scan system are replaced by electronic scanning. Heuristically, we have selected eight consecutive points for beam rotation in a polygon shape and can also be extended almost circular shape by increasing number of array elements and phase shifter (delays) in the delay matrix. The array requires dual control of phase gradient and individual phase values. The whole array is controlled by micro-controller. This presents exciting possibilities in radar operation.     

Bound states and dipole polarizability of hydrogen molecular ion H2 in weakly coupled hot plasmas

The effects of hot-dense plasmas on the bound states and the dipole polarizability of the ground state of Coulomb three-body molecular ion H⁺₂ have been investigated using highly correlated basis functions and by considering the Debye shielding approach of plasma modeling. The ground S state and the first excited P state energies along with the dipole polarizability for different shielding parameters are reported.