http://nopr.niscpr.res.in/handle/123456789/80 2026-10-16T19:20:10Z 2026-10-16T19:20:10Z Kumar, Pawan Kumar, Aravind Dixit, P. N. Sharma, T. P. http://nopr.niscpr.res.in/handle/123456789/206 2008-03-03T04:30:20Z 2007-08-01T00:00:00Z

Title: Study of optical constants in CdxZn₁₋xS vacuum evaporated thin films Authors: Kumar, Pawan; Kumar, Aravind; Dixit, P. N.; Sharma, T. P. Abstract: Thin films of II-VI group semiconductors have been deposited by the vacuum evaporation technique onto highly cleaned glass substrates under the vacuum of the order of 10⁻⁵ torr. The optical properties of these thin films have been determined from transmission spectra by using Manifcier’s envelope method. These films posed, in general good transparency (T > 50%), exhibiting an interference pattern. The wavelength dependence of optical constant (refractive index and extinction coefficient) of these films have been reported. Page(s): 313-316

2007-08-01T00:00:00Z Keshavarz, M H http://nopr.niscpr.res.in/handle/123456789/205 2008-03-03T04:30:23Z 2007-08-01T00:00:00Z

Title: Predicting heats of detonation of explosives via specified detonation products and elemental composition Authors: Keshavarz, M H Abstract: Heats of detonation of CaHbNcOd explosives are predicted using H₂O-CO₂ arbitrary¹ as detonation products as well as ratios of oxygen to carbon (RO/C) and hydrogen to oxygen (RH/O). The methodology at first assumes that the heat of detonation of explosive compound can be approximated as the difference between heats of formation of the assumed detonation products and that of the explosive, divided by the formula weight of the explosive; then may be corrected by RO/C and RH/O. For the calculations in which only H₂O-CO₂ arbitrary were used, predicted heats of detonation for 27 non-aromatic and 31 aromatic energetic compounds have a root mean square (rms) deviation from experiment of 1.21 and 2.08 kJ/g, respectively. The corrected heats of detonation using RO/C and RH/O for both non-aromatic and aromatic energetic compounds have a rms deviation of 0.49 kJ/g from experiment, which show good agreement with respect to measured values. The new method is also applied to four new explosives, i.e., CL-20, FOX-7, ONC and NTO, which gives comparable results as compared to measured values. Page(s): 324-330

2007-08-01T00:00:00Z Sengwa, R J Sankhla, Sonu http://nopr.niscpr.res.in/handle/123456789/204 2008-03-04T04:30:15Z 2007-08-01T00:00:00Z

Title: Low-frequency dielectric response and chain dynamics study of poly(vinyl pyrrolidone)–poly(ethylene glycol) coexisting two-phase polymeric blends Authors: Sengwa, R J; Sankhla, Sonu Abstract: The dielectric response of various concentration poly(vinyl pyrrolidone)-poly(ethylene glycol) (PVP–PEG) blends with change in polymer chain-length and their different volume mixtures over the entire concentration range were investigated in the frequency range 20 Hz-1 MHz at 25ºC. The complex dielectric constant ε*(ω), complex electric modulus M*(ω), complex impedance Z*(ω), and a.c. conductivity data were used for the confirmation of the electrode polarization effect, ionic conduction and the micro-Brownian motion of the PVP chain (m-process) in the PVP–PEG blends. All the blends show the dielectric dispersion corresponding to the PVP segmental motion in the upper experimental frequency range whereas in the lower frequency side of the spectra has dielectric dispersion is due to ionic conduction and electrode polarization. The different volume mixtures of some of the different chain-length PVP–PEG blends also shows the polymer chain-length and concentration dependence m-process. All the blends show the d.c. conductivity behaviour in the lower frequency region, which is little affected by the blends composition. The appearance of two separate arcs in the complex impedance plane plots confirms the contribution of nickel-plated cobal electrodes polarization effect to the values of complex dielectric constant of the PVP–PEG blends in the lower frequency range up to 500 Hz. Page(s): 317-323

2007-08-01T00:00:00Z Sil, Anjan Verma, Pankaj Kumar http://nopr.niscpr.res.in/handle/123456789/203 2008-03-04T04:30:17Z 2007-08-01T00:00:00Z

Title: Synthesis of nanosized AlN powder using novel nitridation route Authors: Sil, Anjan; Verma, Pankaj Kumar Abstract: Nanonsized AlN powders were prepared by nitridation of coarse aluminium powder in flowing N₂ and NH₃ gases, using NH₄Cl and KCl as additives. XRD analysis indicated that the pure phase of AlN powder could be obtained by nitridation at 1000˚C for 4 h with NH₃ gas. The average particle size of the AlN powder estimated from the XRD pattern is about 29 nm. FE-SEM micrograph revealed the spherical morphology of the powder particles whose sizes are in the range of 26-43 nm. Page(s): 309-312

2007-08-01T00:00:00Z