http://nopr.niscair.res.in/handle/123456789/6054 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/6105 Title: State space representation for log domain filtering synthesis <br/> <br/>Authors: Arslanalp, Remzi; Tola, Abdullah T <br/> <br/>Abstract: New method for the state space representation of filters based on the companion form technique has been proposed. It is useful for synthesis of log domain filters. For state space representation of a log domain filter, it is very important to have almost equal coefficients of the state space equations since these coefficients are proportional to currents or voltages of the designed device. The method allows selection of two arbitrary parameters (<img src='/image/spc_char/alpha.gif'>, <img src='/image/spc_char/beta.gif'>) to adjust these coefficients. By using this technique, more balanced state space equations can be obtained. This method offers an option to obtain desired adjustable coefficients. It is particularly useful for synthesizing high order log domain circuits using state space methods. The proposed method is applied to second and fifth order log domain filter designs to show the application. Simulation results demonstrated that different system equations which are determined by the proposed method affect the performance of the filter. <br/> <br/>Page(s): 745-752 http://nopr.niscair.res.in/handle/123456789/6104 Title: Electrode effect on electrical conduction in thin film of polyvinyl pyrrolidone <br/> <br/>Authors: Verma, Ashutosh; Khare, P K; Srivastava, Rudra Kant <br/> <br/>Abstract: Electrical conduction behaviour in ployvinyl pyrrolidone (PVP) has been investigated in both transient and steady state conditions in the temperature range 40-80°C at different <i>dc</i> electric fields from 05 to 100 kV/cm using similar and dissimilar, both types of electrode systems. The nature of transient currents has mainly been attributed to the dipolar nature of PVP in the lower temperature region where slope value <i>n</i> of the Curie Von Schweidler law is found to vary from 0.43 to 0.62 for similar electrode system and from 0.78 to 0.98 for dissimilar electrode system. The low field steady state conduction is found to be ohmic in nature. The high field non-linear nature of conduction currents is found to be strongly temperature dependent and an attempt has been made to explain these curves taking into account various conduction processes. A strong temperature dependence of the conduction current rules out tunnelling as the possible conduction mechanism. The Poole-Frankel and Richardson-Schottky coefficients estimation shows that Richardson-Schottky conduction mechanism is operative in controlling the transport of charges in PVP foil electrets. This result is, further, confirmed using different electrodes systems of Jonscher and Ansari. <br/> <br/>Page(s): 737-744 http://nopr.niscair.res.in/handle/123456789/6103 Title: Nanoscale relaxation near twin-interfaces of palladium and platinum <br/> <br/>Authors: Hayat, Sardar Sikandar; Choudhry, Muhammad A; Hussain, Altaf; Alam, Shabana; Ahmad, Sheikh A; Ahmad, Iftikhar <br/> <br/>Abstract: Molecular dynamics simulation technique with many-body and semi-empirical potentials, based on the embedded atom method is employed to calculate some low index (111), (311), (211) and (210) twin-boundaries at various temperatures. Multilayer relaxation near these twin interfaces for Pd and Pt has also been investigated. For all interfaces except (111), due to high atomic density of (111) plane, considerable relaxation is found on both sides of the interfaces with the same magnitude. The interlayer relaxation near (311) and (211) interfaces is in oscillatory order while near (210) interface is of random nature. Maximum contraction 84.16% and 83.18% for 2^nd interplanar spacing is found for Pd and Pt, respectively. This shows partial coalescence of the planes near (211) twin interface. Furthermore, percentage registry relaxation is calculated for the planes in the vicinity near the interfaces. <br/> <br/>Page(s): 730-736 http://nopr.niscair.res.in/handle/123456789/6102 Title: Estimation of thermodynamical quantities of tin chalcogenides from spectroscopic data <br/> <br/>Authors: Tandon, Pavitra; Uttam, K N <br/> <br/>Abstract: Statistical thermodynamics and spectroscopy have been combined to evaluate thermodynamical quantities of tin chalcogenides (SnO, SnS, SnSe and SnTe). Their temperature dependence has been studied in the temperature range 100-2200K. The authenticity of data is established by the comparison of reported values. Discrepancies between calculated values and observed values can mainly be attributed to contributions from excited electronic states. <br/> <br/>Page(s): 725-729