NOPR Collection:

Polycrystalline ZnSe under solar illumination

Sun, 01 Apr 2001 00:00:00 GMT

Title: Polycrystalline ZnSe under solar illumination Authors: Verma, R N; Saha, D P; Singh, S Abstract: The carrier generation rates of electron-hole pairs in polycrystalline zinc selenide (ZnSe) photovoltaic material have been computed for the first time for AM0, AM1 AM1.5 solar spectra. These theoreticall y computed actual generation rates have heen replaced by a curve filled approximation, which are represented by a series of three exponential terms. A simplified theory has been used for evaluating the solar cell parameters viz. J_sc, V_oc, FF and η for the various solar spectra. Page(s): 271-274

Sound transmission through panels - an experimental study

Sun, 01 Apr 2001 00:00:00 GMT

Title: Sound transmission through panels - an experimental study Authors: Singh, Mahavir; Pujara, K K; Mohanan, V Abstract: Experimental results of measurements on the sound transmission through some lightweight double panels are presented in this paper. The panels are made up of gypsum boards and filled with sound absorptive material such as glass fibre mat in the cavity. The experimental results of the measurements show the precision of measurement for one test panel and the performance of different glass fibre mat densities on the sound transmission loss (TL) , the sound transmission class (STC) and the weighted sound reduction index (R_w). Page(s): 235-239

Study of bulk magnetic properties of the mixed spinel MgCr_xFe_2-xO₄

Sun, 01 Apr 2001 00:00:00 GMT

Title: Study of bulk magnetic properties of the mixed spinel MgCr_xFe_2-xO₄ Authors: Shukla, S J; Jadhav, K M; Bichile, G K Abstract: The polycrystalline samples of the mixed spinel series MgCr_xFe_2-xO₄with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 have been prepared in the pellet form by standard ceramic technique and were studied by means of X-ray diffraction, magnetization and ac susceptibility measurements. The X-ray analysis shows that the samples are formed in a single-phase spinel structure. The lattice parameter a obtained from X-ray data increases initially upto x = 0.4, and thereafter it decreases. The variation of the saturation magnetic moment per formula unit measured at 300K decreases with Cr content x. The ac susceptibility was measured from room temperature to 680 K. The Curie temperature obtained from ac susceptibility measurements decreases nearly linearly with the increase of Cr content x, suggesting the decrease in ferrimagnetic behaviour. Page(s): 226-230

Semi-empirical formulae for electron impact ionization cross-sections

Sun, 01 Apr 2001 00:00:00 GMT

Title: Semi-empirical formulae for electron impact ionization cross-sections Authors: Uddin, M Alfaz; Islam, F N; Shahjahan, M; Choudhury, M G M Abstract: Semi-empirical formulae and BEB models are used to calculate the total cross -sections of single ionizntion of neutral atoms Mg, Al, Si, P, S by electron impact. The parameters of the semiempirical formulae are obtained by fitting the experimental data on the total cross-section of single ionization of the atoms by electron impact over the range of energy varying from the threshold to 200 eV. It is found that the semi-empirical models give qualitatively as well as quantitatively good fits, while BEB model gives qualitative fits to the reference set of experimental data. Page(s): 205-212

NOPR Collection:

Polycrystalline ZnSe under solar illumination

Sound transmission through panels - an experimental study

Study of bulk magnetic properties of the mixed spinel MgCrxFe2-xO4

Semi-empirical formulae for electron impact ionization cross-sections

Study of bulk magnetic properties of the mixed spinel MgCr_xFe_2-xO₄