http://nopr.niscair.res.in/handle/123456789/478 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/7596 Title: Superconductivity in Mg_1-xM_xB₂ (M = Cu and Ag) system <br/> <br/>Authors: Singh, Kiran; Mohan, Rajneesh; Shelke, Vilas; Gaur, N K; Singh, R K <br/> <br/>Abstract: The polycrystalline samples with nominal compositions Mg_1-xM_xB₂ (M = Cu, Ag; x = 0, 0.05) have been synthesized through solid-state reaction method. All the samples were synthesized from the stoichiometric mixtures of Mg, B, Cu and Ag. The samples were sintered at 850°C for 2 h in the presence of high purity argon flow. The X-ray diffraction (XRD), <i style="">R-T</i> measurement and scanning electron microscopy (SEM) techniques have been used for the characterization of samples for phase formation, superconducting transition temperature (<i style="">T</i>_c) and microstructure, respectively. It is noticed from the XRD patterns that the Cu and Ag doping leads to the formation of Mg-Cu and Mg-Ag alloys as the secondary phase, respectively along with the major phase of MgB₂. In case of Cu doping <i style="">T</i>_c decreases slightly and Ag doping has no effect on it. The grain size remains the same with these dopings, but the grain connectivity improves. <br/> <br/>Page(s): 420-422 http://nopr.niscair.res.in/handle/123456789/3057 Title: High output impedance current-mode allpass inverse filter using CDTA <br/> <br/>Authors: Shah, N A; Quadri, Munazah; Iqbal, S Z <br/> <br/>Abstract: A novel current-mode (CM) first-order all-pass (AP) inverse filter has been presented. The proposed circuit has two inputs and a single output with both the inputs providing the first-order all-pass inverse responses independently. The circuit employs bare minimum number of both active and passive components, viz. one each of CDTA, capacitor and resistor. The output current is available at high impedance thereby making the circuit very attractive from the viewpoint of cascadibility. The realizibility condition is simple. The theoretical results are verified by PSPICE simulation. <br/> <br/>Page(s): 893-896 http://nopr.niscair.res.in/handle/123456789/3055 Title: Study of filamentary behaviour in coaxial dielectric barrier discharge lamp <br/> <br/>Authors: Khatun, Hasina; Mishra, Alok; Kumar, Mahesh; Pal, Udit N; Sharma, A K; Barhai, P K <br/> <br/>Abstract: In this study, filamentary discharges have been investigated at 1.5 mm dielectric-dielectric electrode gap of a coaxial dielectric barrier discharge (DBD) quartz tube filled with nitrogen gas. Different types of discharge patterns have been established in the tube using alternating field (35-45 kHz). Electrical characteristics of the discharge have been investigated, which mainly depend on gas pressure, applied frequency and voltage amplitude. The on set of the discharge current occurs earlier at higher operating voltage due to the increased value of E/n, where E is the electric field and n is the neutral gas density. The observed phenomenon occurs due to increase in rate of voltage rise time. At higher voltage, increase in net current increases the chances of electron impact. Analysis of the voltage versus charge plot (lissajous figure) supports the theory of capacitances of a double barrier discharge. The energy consumed per cycle of the DBD source measured using lissajous figure is few milli joules. Energy consumption per cycle is the key parameter for evaluating the efficiency of the device. <br/> <br/>Page(s): 889-892 http://nopr.niscair.res.in/handle/123456789/3054 Title: Characterization of bioactivity in transition metal doped-borosilicate glasses by infrared reflection and dielectric studies <br/> <br/>Authors: Azooz, M A; Aiad, T H M Abou; ElBatal, F H; ElTabii, G <br/> <br/>Abstract: Borosilicate glasses with the addition of one of the 3d-transition metals (Ti→Cu) (0.1 g/100g glass) have been investigated as possible materials having bioactivity by infrared reflection spectroscopy and electrical properties after the immersion in simulated body fluid (SPF) for different interval of times. The results show obvious effects of the transition metal ions on the bioactivity of the borosilicate glasses. The results are discussed taking into consideration recent achievements that govern the formation of hydroxyapatite surface layer on glass. Also, IR and electrical results are discussed in relation to the glass composition and structure, which confirm the effect of the formation of HAp layer and the possible mixed ionic and electronic mechanisms due to the addition of transition metal oxides. <br/> <br/>Page(s): 880-888