http://nopr.niscpr.res.in/handle/123456789/8747 Mon, 05 Oct 2026 11:53:52 GMT 2026-10-05T11:53:52Z http://nopr.niscpr.res.in/handle/123456789/30625 Title: Segregation behaviour of trace metal impurities during ultra high purification of gallium by zone refining Authors: Rambabu, U; Munirathnam, N R; Reddy, R C; Prakash, T L Abstract: <span style="mso-bidi-language:HI">The details of an in-house fabricated laboratory scale horizontal zone-refiner (HZR) for the purification of indigenous 4N (99.99%) gallium have been reported. The purified gallium ingot was analyzed for its selected trace metal impurity <span style="mso-bidi-language:HI">elements, namely Zn, Pb, Cu, AI, Cr, Ni, Fe, B and Mn using inductively coupled plasma optical emission spectrophotometer (ICP-OES). Segregation behaviour of the trace metal impurities throughout the ingot have been illustrated. The repeated experimental results confirm 6N (99.9999%) purity gallium. </span></span> Page(s): 783-786 Sat, 01 Oct 2005 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/30625 2005-10-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/8875 Title: Effect of charge bump on the series resistance and microwave properties of Si <i style="">n</i>⁺<i style="">np</i>⁺ IMPATT diode at X-band Authors: De, P Abstract: The value of series resistance (<i style="">R</i>_s) of Si <i style="">n</i>⁺<i style="">np</i>⁺ IMPATT diode has been studied through computer simulation considering experimental bias current and frequency in the X-band, and the results fit well with the device data (1.6 Ω at 10 GHz) for the flat doping profile. It is further observed that the value of <i style="">R</i>_s decreases from 1.76 to 0.1128 Ω at 10.7 GHz under experimental current density (3.45<img src='/image/spc_char/cross.gif' border=0>10⁶ A.m^-2) and temperature (373K), as the doping profile changes from flat to low-high-low(lhl) type with the incorporation of charge bump. The electric field and the negative resistivity profiles in the depletion layer clearly indicate the advantage of lhl doping profile on the series resistance as well as on its microwave properties. The analysis also gives an idea on the unison of load conductance of the waveguide and negative conductance of the diode at resonance. Page(s): 794-798 Sat, 01 Oct 2005 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/8875 2005-10-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/8874 Title: Ultrasonic study of 1-butanol in pyridine with benzene Authors: Arul, G; Palaniappan, L Abstract: Sound velocity, density and viscosity have been measured in the ternary mixtures of 1-butanol in pyridine with benzene at 303K. Some of the acoustical parameters such as adiabatic compressibility, free length, free volume and internal pressure are calculated from the measured data using the standard relations. The trend shown by the excess parameters of free volume and internal pressure is peculiar that both are negative and in increasing order confirms that the associative nature of alcohol disturbs the molecular symmetry available in benzene molecule. The reduction in the cohesion of dipolar pyridine is also noticed. Page(s): 755-758 Sat, 01 Oct 2005 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/8874 2005-10-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/8873 Title: Study of impedance spectroscopy conducting polymer prepared with the use of water soluble support polymer Authors: Ray, D K; Himanshu, A K; Sinha, T P Abstract: The intrinsically conducting polymer (ICP), polyaniline (PANI) is synthesized by chemical oxidative polymerization process with the help of water soluble support polymer poly-vinyl alcohol (PVA). The field dependence of the dielectric response is measured in the frequency range 50 Hz-1 MHz and temperature range 140-318 K. The frequency dependence of the imaginary impedance (Z'') is found to obey an Arrhenius law with the activation energy of 0.0176 eV. An analysis of real and imaginary parts of dielectric permittivity, conductivity formalism and impedance (Z) with frequency and temperature is performed, showing the polydispersive nature of the sample as confirmed by Cole-Cole plot as well as the scaling behaviour of the Z''. The frequency dependent electrical data are discussed in the context of models for <i style="">dc</i> and <i style="">ac</i> transport in PANI-PVA composite, with the results supporting hopping of charges among positively charged polaron and bipolaron states. These results elucidate that there is an increased coupling among the local dipolar motions (short-range order localized motion). Page(s): 787-793 Sat, 01 Oct 2005 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/8873 2005-10-01T00:00:00Z