http://nopr.niscair.res.in/handle/123456789/8745 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/8851 Title: Evaluation of excess free volumes and excess internal pressures of binary solutions of <i style="">o</i>-chlorophenol at different temperatures <br/> <br/>Authors: Rao, G V Rama; Sarma, A Viswanatha; Ramachandran, D; Rambabu, C <br/> <br/>Abstract: Ultrasonic velocity, density and viscosity have been measured experimentally and free volume as well as internal pressure and enthalpy were calculated for the binary mixtures of <i style="">o</i>-chlorophenol with ethyl benzoate, anisic aldehyde and acetonitrile at 303.15, 308.15, 313.15 and 318.15 K over the entire range of composition. Excess values of free volume, internal pressure, enthalpy and Gibb’s free energy of activation have been calculated for these systems. The results were discussed in the light of existing theories of molecular interactions involved and chemical constitution of the liquid components. <br/> <br/>Page(s): 602-608 Fri, 29 Jul 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8850 Title: CFA-based three input and two outputs voltage-mode universal filter <br/> <br/>Authors: Shah, N A; Rather, M F; Iqbal, S Z <br/> <br/>Abstract: A new voltage-mode (VM) multifunction filter based on, employing two plus type current feedback amplifiers (CFA) and as many capacitors, and three resistors with three inputs and two outputs, is presented. The proposed configuration synthesize all the generic filtering functions namely lowpass (LP), bandpass (BP), highpass (HP), notch (BS) and allpass (AP) with two functions simultaneously, without requiring the change to be induced in the passive elements and/or rotation of components. The circuit enjoys the features of: orthogonal control of the natural frequency and the quality factor, low impedance outputs suiting cascadibility for higher order transfer functions, and low active and passive sensitivities. The results of computer simulation using PSPICE are discussed. <br/> <br/>Page(s): 636-639 Fri, 29 Jul 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8849 Title: High field conduction in amorphous thin films of Se₇₀Te₃₀_-xCd_x in dark and in the presence of light <br/> <br/>Authors: Kushwaha, V S; Mehta, N; Kumar, A <br/> <br/>Abstract: Glassy alloys of Se₇₀Te₃₀_-xCd_x (<i style="">x</i> = 2, 4, 6) are prepared by the quenching technique. Amorphous thin films of these alloys are prepared by the vacuum evaporation technique. Current–voltage (<i style="">I-V</i>) characteristics have been studied at various temperatures in the films in dark and in the presence of light. For this purpose, a <i style="">dc</i> voltage (0 – 300 V) was applied across the film. <i style="">I-V</i> characteristics show that, at low electric fields, an ohmic behaviour is observed. However, at high electric fields (<i style="">E</i> ~ 10⁴ V/cm), the current becomes super ohmic. Analysis of the data shows the absence of space charge limited currents in amorphous Se₇₀Te₃₀_-xCd_x thin films as ln I/V versus <i style="">V</i> curves are not found to be straight lines with high correlation coefficient. Instead, ln <i style="">I</i> versus <i style="">V</i>^1/2 curves are found to be straight lines having high correlation coefficient. The slope of these curves decreases with the increase in temperature. A more detailed analysis shows that the dominant mechanism of conduction is of Poole-Frenkel type in dark as well as in the presence of light. <br/> <br/>Page(s): 630-635 Fri, 29 Jul 2005 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/8848 Title: Spectroscopic studies of gamma-irradiated transition metals-doped soda lime phosphate glass <br/> <br/>Authors: Batal, Fatma H El; Naf, Sherief M Abo <br/> <br/>Abstract: Optical absorption spectra of 3d transition metals have been measured in soda-lime phosphate glass before and after successive gamma irradiation. In general, the transition metals exhibit the lower oxidation state or octahedral coordination in phosphate glass. The experimental optical spectra are related to the respective specific transition of each transition metal ion. Transition metal-doped phosphate glasses reveal varying response to the effect of successive gamma irradiation. The intensity and growth behaviour of the radiation-induced bands are seen to depend on the type of the 3d transition metal. The response of the doped-phosphate glass to gamma rays irradiation is related to the formation of characteristic induced colour centers and the subsequent annihilation or approach of saturation. <br/> <br/>Page(s): 579-590 Fri, 29 Jul 2005 22:58:59 GMT