020162   Vinit Kumar;Mishra G (Beam Physics and Free Electron Laser Laboratory, Raja Ramanna Centre for Advanced Technology, Indore-452 013, Email: vinit@rrcat.gov.in) : Analysis of pulsed wire method for integral measurements in undulators. Pramana J Phys 2010, 74(5), 743-53.

Pulsed wire technique is a fast and accurate method for the measurement of first and second field integrals of undulators used in free-electron lasers and synchrotron light sources. Presents a theoretical analysis of this technique by finding out the analytic solution of the differential equation for the forced vibration of the wire taking dispersion due to stiffness into account. Method of images is used to extend these solutions to include reflections at the ends. For long undulators, the effect of dispersion of the acoustic wave in the wire could be significant and our analysis provides a method for the evaluation of the magnetic field profile even in such cases taking the effect due to dispersion into account in an exact way.

2 illus, 13 ref

020161   Vinayak;Pandey A (Physical Sciences School, Jawaharlal Nehru Univ, New Delhi-110 067, Email: vinayaksps2003@gmail.com ) : Transition from poisson to circular unitary ensemble. Pramana J Phys 2009, 73(3), 505-19.

Transitions to universality classes of random matrix ensembles have been useful in the study of weakly-broken symmetries in quantum chaotic systems. Transitions involving Poisson as the initial ensemble have been particularly interesting. The exact two point t correlation function was derived by one of the present authors for the Poisson to circular unitary ensemble (CUE) transition with uniform initial density. This is given in terms of a rescaled symmetry breaking parameter A. The same result was obtained for Poisson to Gaussian unitary ensemble (GUE) transition by Kunz and Shapiro, using the contour-integral method of Brezin and Hikami. We show that their method is applicable to Poisson to CUE transition with arbitrary initial density. Their method is also applicable to the more general œCUE to CUE transition where ?CUE refers to the superposition of l independent CUE spectra in arbitrary ratio.

1 illus, 30 ref

020160   Vikas Kumar;Chaudhary J;Roy S;Mustaqueem M; Sharma A (Physics Dep, B.R.A. Bihar Univ, Muzaffarpur, Bihar) : Electronic and transport properties of carbon nanotubes. Bull pure appl Sci-Sect D 2010, 29(2), 137-41.

Studied electronic and transport properties of carbon nanotubes using tight-binding models. The depolarization effect shifts the excitation energy to higher energy side and suppresses intensity of the absorption peaks. As a result excitation energy becomes closer to that associated with that of the second gap for parallel polarization. The intensity of the absorption peaks is weakly dependent on the Coulomb interaction and the tube diameter through the cut off energy. The excitation absorption for perpendicular light is systematically studied with emphasis on the depolarization effect and dependence on the strength of the Coulomb interaction and the tube diameter.

4 illus, 10 ref

020159   Vijay Kumar;Singh B K (NO, Tarani Prasad Sinha Advance Study Centre of Science, At-Kashipur, Post-Samastipur, Dist- Samastipur, Bihar, Email: drbksingh@in.com) : Quantum transport properties of 2-D electron gases in hall regime. Bull pure appl Sci-Sect D 2010, 29(1), 43-8.

Studies quantum transport properties of two dimensional electron gases hi Hall regime. We determine the total current I from the bulk Green function. This quantum - mechanical property is an exact result that holds as long as the high-field expansion is applicable. We study the dependence of the plateau width on temperature or disorder broadening. We have numerically computed the Hall conductance including the self consistent equation which is independent of the magnetic field.

2 illus, 9 ref

020158   Verma A S;Sarkar B K;Jindal V K (Physics Dep, Panjab Univ, Chandigarh-160 014, Email: ajay_phy@rediffmail.com) : Cohesive energy of zincblende (A<. Pramana J Phys 2010, 74(5), 851-5.

Presents an expression relating the cohesive energy (E_coh in kcal/mol) of A^IIIB^V and A^IIB^VI semiconductors with the product of ionic charges (Z₁Z₂) and nearest-neighbour distance d (Angstrum). The cohesive energy values of these solids exhibit a linear relationship when plotted on a log-log scale against the nearest-neighbour distance d (Angstrum), but fall on different straight lines according to the ionic charge product of the solids. A good agreement has been found between the experimental and calculated values of the cohesive energy of A^IIIB^V and A^IIB^VI semiconductors.

1 illus, 1 table, 21 ref

020157   Unnikrishnan V K;Alti K;Kartha V B;Santhosh C;Gupta G P;Suri B M (Atomic and Molecular Physics Centre, Manipal Univ, Manipal-576 104, Email: santhosh.cls@manipal.edu) : Measurements of plasma temperature and electron density in laser-induced copper plasma by time-resolved spectroscopy of neutral atom and ion emissions. Pramana J Phys 2010, 74(6), 983-93.

Plasma produced by a 355 nm pulsed Nd:YAG laser with a pulse duration of 6 ns focussed onto a copper solid sample in air at atmospheric pressure is studied spectroscopically. The temperature and electron density characterizing the plasma are measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time window of 300-2000 ns. An echelle spectrograph coupled with a gated intensified charge coupled detector is used to record the plasma emissions. The temperature is obtained using the Boltzmann plot method and the electron density is determined using the Saha-Boltzmann equation method. Both parameters are studied as a function of delay time with respect to the onset of the laser pulse. The results are discussed. The time window where the plasma is optically thin and is also in local thermodynamic equilibrium (LTE), necessary for the laser-induced breakdown spectroscopy (LIBS) analysis of samples, is deduced from the temporal evolution of the intensity ratio of two Cu I lines. It is found to be 700-1000 ns.

7 illus, 2 tables, 12 ref

020156   Uma Maheswari A;prema p;Mahadevan s;Shastry C S (Sciences Dep, Amrita Vishwas vidyapeetham, Ettimadai, Coimbatore-641 105, Email: a_umamaheswari@ettimadai.amrita.edu) : Quasi-bound states, resonance tunnelling, and tunnelling times generated by twin symmetric barriers. Pramana J Phys 2009, 73(6), 969-88.

In analogy with the definition of resonant or quasi-bound states used in three-dimensional quantal scattering, we define the quasi-bound states that occur in one-dimensional transmission generated by twin symmetric potential barriers and evaluate their energies and widths using two typical examples: (i) twin rectangular barrier and (ii) twin Gaussian-type barrier. The energies at which reflectionless transmission occurs correspond to these states and the widths of the transmission peaks are also the same as those of quasi-bound states. Compares the behaviour of the magnitude of wave functions of quasi-bound states with those for bound states and with the above-barrier state wave function. Deduce a Breit-Wigner-type resonance formula which neatly describes the variation of transmission coefficient as a function of energy at below-barrier energies. Similar formula with additional empirical term explains approximately the peaks of transmission coefficients at above-barrier energies as well. Further, studies the variation of tunnelling time as a function of energy and compare the same with transmission, reflection time and Breit-Wigner delay time around a quasi-bound state energy. Also finds that tunnelling time is of the same order of magnitude as lifetime of the quasi-bound state, but somewhat larger.

12 illus, 6 table, 34 ref

020155   Toda Y R;Chaudhari K S;Jain A B;Gujarthi D N (Thin Film Laboratory. Physics Dep, S.V.S.'S Arts & Science College, Dondaicha-425 401, Email: yogeshtoda@gmail.com) : Structural and optical properties of CdSe thin films deposited by chemical bath deposition technique. Asian J chem envir Res 2011, 4(1), 40-3.

Structural and optical properties of multi-layer cadmium selenidethin films of various thicknesses were studied. CdSethin films were prepared by chemical bath deposition method on unheated amorphous glass substrate. The structural investigation performed by X-ray diffraction (XRD) showed that most of the films were polycrystalline in nature. Absorption coefficient of the film was calculated from the optical transmission spectra. It is found that the size of the crystallites in the polycrystalline films determined from XRD measurements and the optical energy band gap, Eg, calculated from optical measurements depend on the thickness and the composition of the films.

6 illus, 12 ref

020154   Toda Y R;Chaudhari K S;Gujarathi D N (Thin Film Laboratory, Physics Dep, Pratap College, Amalner-425 401, Email: tyogeshtoda@gmail.com) : Optical properties of aluminium antimonide thin films prepared by physical evaporation technique. Asian J chem envir Res 2011, 4(1), 24-7.

Aluminium-antimonide is an important material of III-V group compound, it seems a promising semiconducting material for high temperature applications especially for transistors, p-n junction diodes, optoelectronic devices and high energy photon detectors. Thin films having different thicknesses of AlSb were deposited by thermal evaporation technique onto precleaned amorphous glass substrate. The optical band gap of the films was measured by using optical absorption spectra. The Photo Luminescence(PL)study of the films are also studied and it is observed that the peaks are obtained at 488.04, 51 7.29 and 574.8nm shows that zero phonon transition of donor- acceptor pair recombination, where as additional bands corresponds to phonon replicas of the zero phonon DA recombination. The optical microscope indicates the uniform surface coverage. The x ray diffraction analysis confirms that deposited films are polycrystalline having cubic structure. The grain size is found to be 10.75 nm.

5 illus, 1 table, 10 ref

020153   Tiwari S N;Srivastava S;Pandey B;Shukla S N (Physics and Electronics Dep, Dr.R.M.L. Avadh Univ, Faizabad-224 001, Email: sachida.shukla@gmail.com) : Qualitative analysis of small signal high voltage gain triple darlington amplifier. Bull pure appl Sci-Sect D 2010, 29(1), 25-32.

First time we propose a modification in Triple Darlington Amplifier by adding an extra biasing resistance RD and changing the position of emitter bypass capacitor. This modification produces tremendously high voltage gain with improved bandwidth and removes the poor response problem of Triple Darlington amplifiers at higher frequencies. The maximum voltage gain remains unaffected for any change in emitter resistance RE. The proposed amplifier is found useful for amplification of small signals and can be commercially used in various electronics and communication circuits.

5 illus, 11 ref

020152   Tiwari S N;Srivastava S;Pandey B;Shukla S N (Physics and Electronics Dep, Dr. R.M.L. Avadh Univ, Faizabad-224 001, Email: sachida_shukla@yahoo.co.in) : Voltage gain performance of two-stage amplifier, configured by coupling common emitter and Darlington pair amplifiers. Bull pure appl Sci-Sect D 2010, 29(2), 195-204.

Qualitative performance of a two-stage amplifier, configured by coupling a CE amplifier with Darlington pair amplifier is critically analyzed. A significant enlargement in bandwidth on the cost of voltage and current gains is observed. This proposed two-stage amplifier may be quite useful for amplification of small signals up to the voltage range of 25mV and suitable for various analog electronics and communication applications.

8 illus, 13 ref

020151   Tiwari S N;Shukla S N (Physics and Electronics Dep, Dr.R.M.L. Avadh Univ, Faizabad-224 001, Email: sachida_shukla@yahoo.co.in) : Qualitative Analysis of small signal modified Darlington amplifiers. Bull pure appl Sci-Sect D 2009, 28(1), 1-11s.

Modification in Darlington pair amplifier and Triple Darlington amplifiers is proposed. An extra biasing resistance R_D is added in modified amplifiers and position of bypass capacitor C_E is changed in Triple Darlington amplifier. This produces higher voltage gain than conventional Darlington pair amplifier. One of the proposed amplifiers removes the consequences of conventional Darlington pair amplifier at higher frequencies. In modified Triple Darlington amplifier, maximum voltage gain remains unaffected for any change in emitter resistance RE. Proposed amplifiers may be useful for amplification of small signals in mid frequency range and beneficial for various analog communication applications.

11 illus, 11 ref

020150   Tiwari S K;Shukla L J;Upadhyaya K S (NO, Motilal Nehru National Institute of Technology, Allahabad-211 004, Email: sarvesh.tiwari@hotmail.com) : Harmonic dynamical behaviour of thallous halides. Pramana J Phys 2010, 74(5), 793-804.

Harmonic dynamical behaviour of thallous halides (T1C1 and T1Br) have been studied using the new van der Waals three-body force shell model (VTSM), which incorporates the effects of the van der Waals interaction along with long-range Coulomb interactions, three-body interactions and short-range second neighbour interactions in the framework of rigid shell model (RSM). Phonon dispersion curves (PDC), variations of Debye temperature with absolute temperature and phonon density of state (PDS) curves have been reported for thallous halides using VTSM. Comparison of experimental values with those of VTSM and TSM are also reported in the paper and a good agreement between experimental and VTSM values has been found, from which it may be inferred that the incorporation of van der Waals interactions is essential for the complete harmonic dynamical behaviour of thallous halides.

5 illus, 4 tables, 32 ref

020149   Tiwari R K;Mishra J (Circuit Design and Simulation Lab, Physics and Electronics Dep, Dr. R.M.L. Avadh Univ, Faizabad, Uttar Pradesh, Email: rktiwari2323@yahoo.co.in) : New model for distortionless push-pull amplifier. Bull pure appl Sci-Sect D 2010, 29(1), 53-61.

In the investigation the conventional Push-pull amplifier is modified by using some resistors, capacitors and diodes to improve the performance of the circuit. Further the circuit is again modified by using Darlington pair instead of a single transistor which leads the circuit towards the best performance decreasing the numbers of passive devices.

020148   Thangapandian S;Arumugam V;Kannappan A N (Physics Dep, Annamalai Univ, Annamalainagar-608 002) : Molecular interaction in ternary liquid mixtures-an ultrasonic study. Bull pure appl Sci-Sect D 2009, 28(1), 53-8.

The experimental data for ultrasonic velocity, density and viscosity was recorded for the ternary systems of 1-propanol and acetophenone with chlorobenzene, bromobenzene and nitrobenzene at 303, 308 and 313K. From the experimental data, the adiabatic compressibility, free length, free volume and internal pressure for the mixtures were calculated. The formation of H-bond of type X- H-O (X= Cl, Br and NO₂) and the attractive interaction present in halogen mixtures were discussed.

4 illus, 2 table, 13 ref

020147   Tel E;Aydin A;Aydin E G;Kalpna A;Yavas O; Reyhancan I A (Physics Dep, Faculty of Arts and Science, Gazi Univ, TR-06500 Ankara, Turkey, Email: eyuptel@gazi.edu.tr) : Newly developed semi-empirical formulas formulas for (p,α) at 17.9 MeV and (p, np) at 22.3 MeV reaction cross-sections. Pramana J Phys 2010, 74(6), 931-43.

Investigated the asymmetry term effect for the (p, α) and (p, np) reaction cross-sections and obtained new coefficients for the (p, α) and (p, np) reaction cross-sections at 17.9 and 22.3 MeV energies. We have suggested semi-empirical formulas including the non-elastic effects of optical model found by fitting two parameters for proton-induced reactions. The coefficients were determined by least-square fitting method. The obtained cross-section formulas with new coefficients have been discussed and compared with the available experimental data.

12 illus, 2 tables, 40 ref

020146   Tarafdar S;De S K;Manna S;De Udayan;Nanda P (Physics Dep, Condensed Matter Physics Research Centre, Jadavpur Univ, Kolkata-700 032, Email: sujata_tarafdar@hotmail.com) : Variation in viscosity and ion conductivity of a polymer-salt complex exposed to gamma irradiation. Pramana J Phys 2010, 74(2), 271-79.

Study changes in microstructure and resulting changes in the properties of PEO(1 - x:)-NH₄ ClO₄(x;) samples where x = 0.18, when irradiated with gamma doses varying up to 50 kGy. Viscosities of aqueous solutions of the irradiated samples give an idea of the change in molecular weight and show correlation with ion conductivity. On the whole, there is a chain scission on irradiation, though there is evidence of some cross-linking at higher doses. The ion conductivity shows a strong increase for an irradiation of 35 kGy. DSC studies indicate a decrease in crystallinity with gamma dose.

5 illus, 22 ref

020145   Szmoski R M;De S;Pinto S E;Van Kan M T; Batista A M (Departamento de Fisca, Estadual de Ponta Grossa, 84030-900, Ponta Grossa, PR, Brazil, Email: antoniomarcosbatista@gmail.com ) : Synchronization and suppression of chaos in non-locally coupled map lattices. Pramana J Phys 2009, 73(6), 999-1009.

Consideres coupled map lattices with long-range interactions to study the spatiotemporal behaviour of spatially extended dynamical systems. Coupled map lattices have been intensively investigated as models to understand many spatiotemporal phenomena observed in extended system, and consequently spatiotemporal chaos. Used the complex order parameter to quantify chaos synchronization for a one-dimensional chain of coupled logistic maps with a coupling strength which varies with the lattice in a power-law fashion. Depending on the range of the interactions, complete chaos synchronization and chaos suppression may be attained. Furthermore, we also calculated the Lyapunov dimension and the transversal distance to the synchronization manifold.

8 illus, 31 ref

020144   Subramanian M K;Anbarasan P M;Manimegalai S (Physics Dep, Periyar Univ, Salem-636 011, Email: anbarasanpm@gmail.com) : Molecular structure, vibrational spectroscopic studies and natural bond orbital analysis of 7-amino-4-trifluoromethyl coumarin. Pramana J Phys 2010, 74(5), 845-50.

Quantum mechanical calculations of energies, geometries and vibrational wave numbers of 7-amino-4-trifluoromethyl coumarin (7A4TFMC) were carried out using Hartree-Fock (HF) and density functional theory (DFT) using hybrid functional BLYP and B3LYP with 6-31G(d,p) as basis set. The optimized geometrical parameters obtained by HF and DFT calculations are in good agreement with the experimental-X-ray data. The best method to reproduce the experimental wave numbers is B3LYP method with the 6-31G(d,p) basis set. The difference between the observed and scaled wave number values of most of the fundamentals is very small. A detailed interpretation of the infrared spectra of 7A4TFMC was also reported. The entropy of the title compound was also performed at HF using the hybrid functional BLYP and B3LYP with 6-31 G(d,p) as basis set levels of theory. Natural bond orbital (NBO) analysis of the title molecule is also carried out. The theoretical spectrogram for FTIR spectra of the title molecule has been constructed.

1 illus, 20 ref

020143   Srivastava N;Srivastava P C (Physics Dep, Banaras Hindu Univ, Varanasi-221 005, Email: pcsrivastava50@gmail.com) : Realizing NiO nanocrystals from a simple chemical method. Bull Mater Sci 2010, 33(6), 653-6.

Nanocrystalline NiO has been prepared successfully by a simple chemical route using NiCl₂'6H₂O and NaOH aqueous solution at a temperature of 70°C. The prepared material has been characterized from XRD, SEM, and M-H characteristics. It has been found that NiO nanocrystals have been formed which shows a superparamagnetic/superantiferromagnetic behaviour.

3 illus, 1 table, 21 ref

020142   Sriramachandran P;Shanmugavel R;Rajamanickam N (Physics Research Center, VHNSN College, Virudhunagar-626 001, Email: sri_ramnivash@rediffmail.com) : Transition probability parameters for CrH and CrD molecules. Asian J Spectrosc 2010, 14(1-2), 35-8.

Transition probability parameters like Franck - Condon (FC) factor and r-centroid for the band system A⁶∑⁺- X⁶∑⁺ of CrFI and CrD molecules have been estimated. RK.R (Rydberg - Klein - Rees) potentials were used for both electronic states and exact vibrational eigenfunctions were obtained by numerical solutions of the radial Schrodinger equation in which the realistic potential energy functions were calculated at equal intervals of 0.01 A in the range of internuclear distances. The FC factors are more intense particularly for the (0, 0) bands, for both the systems examined here. Further the bands of the molecules are expected to be present in sunspots spectra, M stars, brown dwarfs and other prominent astrophysical sources.

3 tables, 10 ref

020141   Solanki G K;Patel D B;Unadkat S;Agarwal M K (Physics Dep, Sardar Patel Univ, Vallabh Vidyanagar-388 120, Email: solankigunvant@yahoo.co.in) : Synthesis and characterization of germanium monosulphide (GeS) singal crystals grown using diffrent transporting agents. Pramana J Phys 2010, 74(5), 813-25.

This paper reports the growth of germanium monosulphide (GeS) single crystals by vapour phase technique using different transporting agents. The single crystallinity and composition of the grown crystals have been verified by transmission electron microscopy (TEM) and energy dispersive analysis of X-rays (EDAX) respectively. Resistivity measurements have been carried out in different temperature ranges. Transport parameters, e.g. resistivity, Hall coefficient, carrier concentration and mobility have been measured at varying magnetic fields. All the experimental results have been explained.

7 illus, 6 tables, 16 ref

020140   Singh Y P;Tomar A S;Vijay S K (Physics Dep, Govt. Polytechnic College, Sagar-470 001, Email: y_p_s_2k@yahoo.com) : Vibrational properties of 2-chloro-10-(3-[4-(2-hydroxyethyl)-piperazin-1-yl) propyl phenothiazine - 'Perphenazine' : an anti AIDS drug. Asian J Spectrosc 2010, 14(1-2), 57-61.

Perphenazine has shown great promise in inhibiting the human immuno deficiency virus and in reducing mortality among AIDS patients. Fourier transform infrared spectrum was recorded and analyzed. Making use of the recorded data, the vibrational assignments are made and analysis of the observed fundamental bands of molecule is carried out. The experimental determinations of vibrational frequencies are compared with those obtained theoretically from semi empirical, ab initio and DFT quantum mechanical calculations using semi emperical/PM3, ab-initio/6-311++G*, and B3LYP/6-311++G* methods. The spectra exhibit distinct features originating from low frequency vibrational modes caused by intra-molecular motion. The normal modes of vibrations obtained from ab initio and DFT (B3LYP) calculations are in good agreement with the experimentally observed data. Comparison of the simulated spectra provides important information about the ability of the computational method (B3LYP) to describe the vibrational modes.

4 illus, 1 table, 16 ref

020139   Singh Y P;Tomar A S;Vijay S K (Physics Dep, Govt. Women's Polytechnic College, Sagar-470 001, Email: y_p_s_2k@yahoo.com) : Study on experimental and theoretical vibrational spectra of novel anti AIDS drug: Zidovudine- Iron metal complex derived from 3' -Azido-2' -deoxythymidine. Asian J Spectrosc 2010, 14(1-2), 47-55.

A combined experimental and theoretical study on molecular and vibrational structure metal complex of 3'-Azido-2'-deoxythymidine (Zidovudine AZT) with Fe(III) have been reported. The Fourier transform infrared spectra of was recorded in the solid phase, in the region of 2500-400 cm^-1. Assuming C point symmetry, vibrational assignments for the observed frequencies have been proposed and energies of this molecule have also been calculated by means of quantum chemical calculations using density functional theory and Hartree-Fock method with 6-311++G** basis sets. An assignment of normal modes of vibration to the observed frequencies has been based on these calculations. The theoretical wavenumbers showed very good agreement with the experimental values. A detailed interpretation of the infrared also is reported. The theoretical FT-1R spectra of the title molecule have also been constructed.

4 illus, 4 tables, 24 ref

020138   Singh S S;Gosain D S;Yogesh Kumar;Jha A K (Physics and Astrophysics Dep, Delhi Univ, Delhi-110 007, Email: sssingh@@physics.du.ac.in) : Effect of curvature on a statistical model of quark-gluon-plasma fireball in the hadronic medium. Pramana J Phys 2010, 74(1), 27-37.

The free energy of a quark-gluon plasma fireball in the hadronic medium is calculated in the Ramanathan et al statistical model after incorporating the effect of curvature. The result with the inclusion of curvature is found to produce significant improvements in all the parameters we calculated with respect to the earlier results. The surface tension with this curvature effect is found to be 0.17 T³_c which is two times the earlier value of surface tension which is 0.078 T³_c and this new result is nearly close to the lattice value 0.24 T³_c. As far as transition is concerned, a thermodynamic variable like entropy shows weakly first-order phase transition and it shows continuity in the behaviour of specific heat.

6 illus, 2 table, 17 ref

020137   Singh S P;Mazumdar K;Singh J B (NO, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005, Email: mazumdar@tifr.res.in) : Search for B_s-μμγ at large hadron collider. Pramana J Phys 2010, 74(1), 39-47.

The branching ratio for B_s -l⁺lγ mode is of the same order as B_s -l⁺l^- since there is no helicity suppression in the 3-body decay mode. New Physics beyond Standard Model may affect these rates favourably for experimental observation at LHC and simultaneous measurements of the modes B_s -μ⁺ μ^-and B_s -μ⁺ μ^-γ at LHC experiment will indicate the basic nature of the interaction at play. A simulation study has been performed to evaluate the potential of CMS detector to observe the more difficult mode of B_s -μ⁺ μ^-γ. An upper limit of 2.08 x 10^-7 on the branching ratio is expected to be achieved corresponding to an integrated luminosity of 10 fb^-1.

3illus, 2 tables, 9 ref

020136   Singh R;Uttam K N;Saksena M D;Deo M N (Saha's Spectroscopy Laboratory, Physics Dep, Allahabad Univ, Allahabad-211 002, Email: kailash.uttak@rediffmail.com) : Vibrational analysis of fourier transform spectrum of the A <. Pramana J Phys 2009, 73(5), 889-99.

The emission spectrum of InBr molecule has been recorded in the region 350-400 nm on BOMEM DAS Fourier transform spectrometer at an apodized resolution of 0.06 cm^-1 using microwave excitation technique. About 61 violet degraded and single headed bands have been recorded and are classified into two band systems, viz. A³II₀-X¹⇔⁺ and B³II₁-X¹⇔⁺ A few new bands have been observed and are fitted in the vibrational schemes of the two systems. Revised vibrational constants have been determined. The vibrational assignments have been confirmed by observing isotope effect due to InBr⁸¹ in the 30 bands of the A³II₀-X¹⇔⁺system and 19 bands of the B³II₁-X¹⇔⁺ system. The analysis is further supported by calculating the Franck-Condon factor for InBr⁷⁹ and InBr⁸¹ molecules.

12 illus, 3 tables, 25 ref

020135   Singh N;Lahiri S;Jayannavaram (Physics Institute, Sachivalaya Marg, Bhubaneswar-751 005, Email: lahiri@iopb.res.in) : Energy fluctuations in a biharmonically driven nonlinear system. Pramana J Phys 2010, 74(3), 331-49.

Study the fluctuations of work done and dissipated heat of a Brownian particle in a symmetric double well system. The system is driven by two periodic input signals that rock the -potential simultaneously. Confinement in one preferred well can be achieved by modulating the relative phase between the drives. We show that in the presence of pumping the stochastic resonance signal is enhanced when analysed in terms of the average work done on the system per cycle. This is in contrast with the case when pumping is achieved by applying an external static bias, which degrades resonance. We analyse the nature of work and heat fluctuations and show that the steady state fluctuation theorem holds in this system.

14 illus, 49 ref

020134   Singh M;Srivastava S;Agarwal S;Kumar S;Vijay Y K (Physics Dep, Rajasthan Univ, Jaipur-302 004) : Optical properties of d.c. magneto sputtered tantalum and titanium nanostructure thin film metal hydrides. Bull Mater Sci 2010, 33(5), 569-73.

Nanostructured thin films of tantalum and titanium were deposited on glass substrate using d.c. magnetron sputtering technique under the argon gas environment at a pressure of 0-1 mbar. Optical transmission and absorption studies were carried out for these samples with pressure of hydrogen. Large changes in both transmission and absorption on loading these films with hydrogen are accompanied by significant phase changes and electronic transformation. Optical photograph shows the colour variation after hydrogena-tion in case of tantalum film which may be used as decorative mirrors and hydrogen sensors. The hydrogen storage capability of thin films was confirmed by variation in optical properties.

8 illus, 20 ref

020133   Singh K B (Physics Dep, Govt. Polytechnic, Dharbhanga-846 004, Email: kbsphysics@yahoo.co.in) : Study of variation of selectivity of microstripline with strip geometry and operating frequency. Bull pure appl Sci-Sect D 2009, 28(1), 21-8.

Characteristic impedance, Phase velocity, Attenuation constant and Selectivity, which are important parameters to be discussed. The metallic and dielectric loss has been also calculated for the study of selectivity of rnicrostriplines with fused quartz as substrate and its variation with strip width and operating frequency-using computer added technique. The calculation of selectivity of the microstripline structure keeping strip width and permittivity fixed has been carried out for different frequencies. In the growing edge of computer and information technology the communication system has shrinked to a miniaturized size, lightweight and less expansive. It is due to advent of microwave integrated circuit (MIC's), which gave birth to planar microwave transmission structure. Microstripline structure appears to be the most convenient and easy to fabricate. This furnishes very useful information for designing microstrip line coupler and resonators of high selectivity.

5 illus, 11 ref

020132   Singh G;Shrivastava S B;Jain D;Pandya S; Shripathi T;Ganesan V (School of Studies in Physics, Vikram Univ, Ujjain-456 010, Email: girijesh.s@gmail.com) : Effect of indium doping on zinc oxide films prepared by chemical spray pyrolysis technique. Bull Mater Sci 2010, 33(5), 581-7.

Reports the conducting and transparent In doped ZnO films fabricated by a homemade chemical spray pyrolysis system (CSPT). The effect of In concentration on the structural, morphological, electrical and optical properties have been studied. These films are found to show (0 0 2) preferential growth at low indium concentrations. An increase in In concentration causes a decrease in crystalline quality of films as confirmed by X-ray diffraction technique which leads to the introduction of defects in ZnO. Indium doping also significantly increased the electron concentrations, making the films heavily n type. However, the crystal-Unity and surface roughness of the films decreases with increase in indium doping content likely as a result of the formation of smaller grain size, which is clearly displayed in AFM images. Typical optical transmittance values in the order of (80%) were obtained for all films. The lowest resistivity value of 0-045 Ω-m was obtained for film with 5% indium doping.

6 illus, 1 table, 28 ref

020131   Singh D;Singh R P (NO, Indian Institute of Tropical Meterology, Dr. Homi Bhabha Road, Pashan, Pune-411 008, Email: devendraasingh@tropmet.res.in) : The role of cosmic rays in the earth's atmospheric processes. Pramana J Phys 2010, 74(1), 153-68.

In this paper, authors have provided an overview of cosmic ray effects on terrestrial processes such as electrical properties, global electric circuit, lightning, cloud formation, cloud coverage, atmospheric temperature, space weather phenomena, climate, etc. It is suggested that cosmic rays control short-term and long-term variations in climate. There are many basic phenomena which need further study and require new and long-term data set. Some of these have been pointed out.

3 illus, 86 ref

020130   Singh A P;Bhat P C;Mokhov N V;Beri S (Physics Dep, Panjab Univ, Chandigarh-160 014, Email: anil79@fnal.gov) : Beam-induced radiation in the compact muon solenoid tracker at the large hadron collider. Pramana J Phys 2010, 74(5), 719-29.

The intense radiation environment at the Large Hadron Collider, CERN at a design energy of √s - 14 TeV and a luminosity of 10³⁴ cm^-2 s^-1 poses unprecedented challenges for safe operation and performance quality of the silicon tracker detectors in the CMS and ATLAS experiments. The silicon trackers are crucial for the physics at the LHC experiments, and the inner layers, being situated only a few centimeters from the interaction point, are most vulnerable to beam-induced radiation. We have recently carried out extensive Monte Carlo simulation studies using MARS program to estimate particle fluxes and radiation dose in the CMS silicon pixel and strip trackers from proton-proton collisions at √s = 14 TeV and from machine-induced background such as beam-gas interactions and beam halo. We will present results on radiation dose, particle fluxes and spectra from these studies and discuss implications for radiation damage and performance of the CMS silicon tracker detectors.

7 illus, 2 tables, 8 ref

020129   Singh A K;Chouddhari J;Ashok Kumar;Verma D K; Ranjan M (NO, HNK Inter College, Ara, Bihar) : Influence of temperature and the filling of states on the conductivity of a variable range Hopping system with an exponential distribution of locallized state energies. Bull pure appl Sci-Sect D 2009, 28(1), 47-51.

A carrier may either hop over a small distance with a high activation energy or hop over a long distance with a low activation energy. The temperature dependence of the carrier transport in such a system is strongly dependent on the density of localized states. In a field effect transistor, an applied gate voltage gives rise to the accumulation of charge carriers in the region of the semiconducting layer that is close to the insulator. As these accumulated charge carriers fill the lower lying states of the organic semiconductor, any additional charges in the accumulation layer occupy states at relatively high energies. This causes higher mobility.

2 illus, 7 ref

020128   Siegl P (Faculty of Nuclear Sciences and Physical Engineering, , Prague, Czech Republic, Email: siegl@ujf.cas.cz) : Non-eqivalence of pesudo-Hermiticity and presence of antilinear symmetry. Pramana J Phys 2009, 73(2), 279-86.

The non-equivalence of the presence of antilinear symmetry and pseudo-Hermiticity is shown for bounded operators. Two appropriate examples are operators with non-empty residual spectrum. The class of operators for which the equivalence holds is extended to the spectral operators of scalar type. The importance of J-self-adjointness is stressed and new proofs using this property are provided.

17 ref

020127   Shukla A K;Agrawal V K;Das I M L;Janardan Singh;Srivastava S L (Physics Dep, Allahabad Univ, Allahabad-211 002, Email: akshukla@amity.edu) : Temperature dependence of electromechanical properties of PLZT x/57/43 ceramics. Bull Mater Sci 2010, 33(4), 383-90.

The compositions of lead lanthanum zirconate titanate PLZT [Pb(Zr_0.57Ti_0.43O₃ + x at % of La, where x = 3, 5, 6, 10 and 12] have been synthesized using mixed oxide route. The temperature dependent electromechanical parameters have been determined using vector impedance spectroscopy (VIS). The charge constant d₃₁ and elastic compliance S^E₁₁ show a peak in all the samples at a temperature T_mt much below the ferroelectric - paraelectric transition temperature, whereas the series resonance frequency f_s shows a dip at these temperatures. The Poisson's ratio σ^E increases with temperature T showing a broad peak at a temperature higher than T_mt. The voltage constant g₃₁ decreases and the planar coupling coefficient K_p remains constant up to half of the T_mt and then falls sharply with T. Half of the T_mt can, therefore, be used for specifying the working temperature limit of the piezoceramics for the device applications.

12 illus, 4 tables, 29ref

020126   Shrimali M D;Poria S;Sinha S (NO, The LNM Institute of Information Technology, Jaipur-302 031, Email: sudeshna@imsc.res.in) : Under what kind of parametric fluctuations is spatiotemporal regularity the most robust. Pramana J Phys 2010, 74(6), 895-906.

It was observed that the spatiotemporal chaos in lattices of coupled chaotic maps was suppressed to a spatiotemporal fixed point when some fractions of the regular coupling connections were replaced by random links. Here we investigate the effects of different kinds of parametric fluctuations on the robustness of this spatiotemporal fixed point regime. In particular we study the spatiotemporal dynamics of the network with noisy interaction parameters, namely fluctuating fraction of random links and fluctuating coupling strengths. We consider three types of fluctuations: (i) noisy in time, but homogeneous in space; (ii) noisy in space, but fixed in time; (iii) noisy in both space and time. We find that the effect of different kinds of parametric noise on the dynamics is quite distinct: quenched spatial fluctuations are the most detrimental to spatiotemporal regularity; spatiotemporal fluctuations yield phenomena similar to that observed when parameters are held constant at the mean value, and interestingly, spatiotemporal regularity is most robust under spatially uniform temporal fluctuations, which in fact yields a larger fixed point range than that obtained under constant mean-value parameters.

5 illus, 19 ref

020125   Shetty A;Jali V M;Ganesh Sanjeev;Parui J; Krupanidhi S B (Physics Dep, Gulbarga Univ, Gulbarga-585 106, Email: vmjali@rediffmail.com) : Dielectric properties of electron irradiated PbZrO₃ thin films. Bull Mater Sci 2010, 33(3), 191-6.

Deals with the study of the effects of electron (8 MeV) irradiation on the dielectric and ferroelectric properties of PbZrO₃ thin films grown by sol-gel technique. The films were (0-62 μm thick) subjected to electron irradiation using Microtron accelerator (delivered dose 80, 100, 120 kGy). The films were well crystallized prior to and after electron irradiation. However, local amorphization was observed after irradiation. There is an appreciable change in the dielectric constant after irradiation with different delivered doses. The dielectric loss showed significant frequency dispersion for both unirradiated and electron irradiated films. T_c was found to shift towards higher temperature with increasing delivered dose. The effect of radiation induced increase of ε(T) is related to an internal bias field, which is caused by radiation induced charges trapped at grain boundaries. The double butterfly loop is retained even after electron irradiation to the different delivered doses. The broader hysteresis loop seems to be related to radiation induced charges causing an enhanced space charge polarization. Radiation-induced oxygen vacancies do not change the general shape of the AFE hysteresis loop but they increase P_s of the hysteresis at the electric field forced AFE to FE phase transition. We attribute the changes in the dielectric properties to the structural defects such as oxygen vacancies and radiation induced charges. The shift in T_c, increase in dielectric constant, broader hysteresis loop, and increase in P_r can be related to radiation induced charges causing space charge polarization. Double butterfly and hysteresis loops were retained indicative of AFE nature of the films.

7 illus, 1 table, 21 ref

020124   Sheoran M S;Kishore N;Dhar R;Maan A S (Applied Physics Dep, Guru Jambheshwar Univ of Science & Technology, Hisar-125 001, Email: mssheoran31@gmail.com) : FTIR and Raman spectra of xB₂O₃ (95-x) TeO₂ 5Fe₂ O₃ glasses. Asian J Spectrosc 2010, 14(3-4), 85-92.

Iron doped borotellurite glasses have been prepared by standard melt-quenching technique. The samples have been characterized as amorphous by X-ray diffraction technique. The density has also been measured and it is found to decrease with increase in B₂O₃ contents. FT-IR spectra of synthesized samples have been measured at room temperature, in the range 400-4400 cm^-1. New absorbed peaks/bands start developing on addition of B₂O₃. Raman spectra have also been taken for some samples and are discussed here.

4 illus, 3 tables, 30 ref

020123   Sharma U S;Verma U P (Physics Dep, RJIT. BSF Academy, Tekanpur, Gwalior-475 005, Email: umashankar_rjit@yahoo.co.in ) : High pressure phase transition from B3 to B1 of GaAs using Density functonal theory. Asian J chem envir Res 2011, 4(1), 50-3.

In recent years, gallium arsenide (GaAs) has gained recognition as being the most important material for optoelectronic and electronics applicationsduetotheirmaterial properties. In this work, high pressure phase transition from zincblende (B3 type) to sodium chloride (B1 type) structure and study of structural and electronic properties of GaAs are investigated. The calculations are performed using SIESTA code which is based on density functional theory (DFT) and PBE parameterization scheme has been used for exchange-correlation energy of the electrons. The structural properties of GaAs in B3 and 81 are presented. The lattice constant, bulk modulus and its pressure derivatives are calculated made detailed comparison with early reported theory as well as experimental results. In most of the cases our calculated values are in good agreement with them.

2 illus, 1 table, 14 ref

020122   Sharma P K;Singh R;Bora D (NO, Institute for Plasma Research, Bhat, Gandhinagar-382 428, Email: pramod@ipr.res.in) : Low-frequency fluctuations in pure toroidal magnetized plasma. Pramana J Phys 2009, 73(6), 1073-86.

A magnetized, low-β plasma in pure toroidal configuration is formed and extensively studied with ion mass as control parameter. Xenon, krypton and argon plasmas are formed at a fixed toroidal magnetic field of 0.024 T, with a peak density of <126> 10¹¹ cm^-3, <126>4 x 10¹⁰ cm^-3 and <126> 2 x 10¹⁰ cm^-3 respectively. The experimental investigation of time-averaged plasma parameter reveals that their profiles remain insensitive to ion mass and suggests that saturated slab equilibrium is obtained. Low-frequency (LF) coherent fluctuations (ω <60> ω_ci) are observed and identified as flute modes. Here ω_ci represents ion cyclotron frequency. Results indicate that these modes get reduced with ion mass. The frequency of the fluctuating mode decreases with increase in the ion mass. Further, an attempt has been made to discuss the theory of flute modes to understand the relevance of some of our experimental observations.

8 illus, 19 ref

020121   Sharma J;Kumar S (Physics Dep, Christ Church College, Kanpur-208 001, Email: dr_santosh_kr@yahoo.com) : Dielectric relaxation in glassy Se₇₅In_25-xPb_x alloys. Pramana J Phys 2010, 74(3), 411-20.

In this paper we report the effect of Pb incorporation in the dielectric properties of a-Se₇₅In₂₅ glassy alloy. The temperature and frequency dependence of the dielectric constants and the dielectric losses in glassy Se₇₅In_25-xPb_x (x = 0, 5,10 and 15) alloys in the frequency range (1 kHz-5 MHz) and temperature range (300-340 K) have been measured. A detailed analysis shows that the dielectric losses are dipolar in nature and can be understood in terms of hopping of charge carriers over a potential barrier as suggested by Elliott for the case of chalcogenide glasses. It has been found that both dielectric constant and the dielectric loss are highly dependent on frequency and temperature and also found to increase with increasing concentration of Pb in binary a-Se₇₅In₂₅ glassy system. The results have been interpreted in terms of increase in the density of defect states by the incorporation of Pb as a metallic additive in the aforesaid glassy system.

11 illus, 1 table, 21 ref

020120   Sharma A;Pathak K K;Asim Kumar;Chaudhary J; Abhishek Madan J (Physics dep, R.D.S College, Muzaffarpur, Bihar) : Finite frequency current noise for one dimensional electron system in the presence of a scatterer. Bull pure appl Sci-Sect D 2010, 29(1), 49-51.

Studied that the current noise exhibited long wave length spatial oscillations, which depend on the noise frequency, the Fermi velocity, distance between the point of measurement and the impurity in the quantum wire. We have explained non interacting systems with linear dispersion, where the origin of the spatial oscillations were easily seen. These noise oscillations were affects by band curvature and Coulomb interaction. A finite band curvature calculation shows that the spatial oscillations decay away from the impurity site and show a beating behaviour. Coulomb interaction have been taken into account by describing the quantum wire as a Luttinger liquid, suppresses the amplitude of the noise oscillations.

020119   Sen A (Physics Dep, Suri Vidyasagar College, Suri-731 101, Email: abhijisen@yahoo.co.in) : Flavour equilibration studies of quark-gluon plasma with non-zero baryon density. Pramana J Phys 2009, 73(6), 1041-57xsxs.

Flavour equilibration for a thermally equilibrated but chemically non-equilibrated quark-gluon plasma is presented. Flavour equilibration is studied enforcing baryon number conservation. In addition to the usual processes like single additional gluon production gg ↔ ggg and its reverse and quark-antiquark pair production by gluon pair fusion gg ↔ q_iq_i and reverse thereof, processes like quark-flavour interchanging q_iq_i ↔ q_jq_j is also considered. The degree of equilibration is studied comparatively for various reactions/constraints that are being considered.

2 illus, 18 ref

020118   Sapkal M R;Sapkal R T;Deshmukh A M (Microbiology Dep, B.D. College, Patan, Dist. Satara-415 206, Email: mr_sapkal@yahoo.co.in) : Intracellular biosynthesis of silver nanoparticles using Streptomyces species. Res J Biotechnol 2009, 4(3), 56-8.

The development of eco-friendly, reliable process for the synthesis of nanomaterials is an important aspect using microorganisms. We have concentrated on the use of actinornycetes in the intracellular biosynthesis of silver nanoparticles. When different species of Streptomyces viz Streptomyces rameus NBR and Streptomyces spp. LD021 were exposed to aqueous 10^-3M AgNO₃ solution at 28°C± 0.5°C for 72 hours under optimum conditions synthesizing silver nanoparticles intracellularly, particle size is in the range of 12 nm. to 22 nm. The characterization was carried out by using UV visible spectrophotometer, XRD, SEM techniques.

4 illus, 12 ref

020117   Santosh K P;Biju R K;Sahadevan S (School of Pure and Applied Physics, Kannur Univ, Payyanur Campus, Payyanur-670 327, Email: kpsanthosh@eth.net) : Stabillity of244-260Fm iotopes against alpha and cluster radioactivity. Pramana J Phys 2009, 73(6), 1059-72.

Taking Coulomb and proximity potentials as the interacting barrier we have studied the cold valley in the radioactive decay of ^244-260Fm isotopes. It is found that in addition to alpha particle minima, other minima occur at S, Ar and Ca clusters. We have computed the half-lives and other characteristics of different clusters emitted from these parents treating parent, daughter and emitted cluster as spheres. Our study reveals that most of these parents are unstable against alpha and heavy cluster (⁴⁶Ar, ^48,50Ca) emissions and stable against light cluster emission, except ⁸Be from ^244-248Fm isotopes. The most probable clusters from these parents are predicted to be ⁴⁶Ar, ^48,50Ca which indicate the role of doubly or near doubly magic clusters (Z = 20, TV = 28) and also stress the role of doubly magic ²⁰⁸Pb daughter. The computed half-lives for alpha decay are in good agreement with the experimental data. It is found that the presence of neutron excess in the parent nuclei slows down the cluster decay process. The effect of quadrupole (β₂) and hexadecapole (β₄) deformations of parent and fragments on half-lives are also studied. It is found that inclusion of β₂and β₄ reduces the height and shape of the barrier (increases barrier penetrability) and hence the half-life decreases.

4 illus, 4 table, 49 ref

020116   Sanjeev Kumar;Suneel Kumar (Physics and Material Science School, Thapar Univ, Patiala-147 004, Email: suneel.kumar@thapar.edu) : Comparative study of model ingredients: fragmentation in heavy-ion collisions using quantum molecular dynamics model. Pramana J Phys 2010, 74(5), 731-42.

Aims to understand the role of NN cross-sections, equation of state as well as different model ingredients such as width of Gaussian, clusterization range and different clusterization algorithms in multifragmentation using quantum molecular dynamics model. We notice that all model ingredients have sizable effect on the fragment pattern.

4 illus, 19 ref

020115   Saji V S;Choe H C (Chosun Univ, College of Dentistry and 2nd Stage of Brain Korea 21 for College of De, Gwangju 501-759, Republic of Korea, Email: vssaji@chosun.ac.kr) : Chemical solution deposition of CaCu₃Ti₄O₁₂ thin film. Bull Mater Sci 2010, 33(3), 203-7.

CaCu₃Ti₄O₁₂ (CCTO) thin film was successfully deposited on boron doped silica substrate by chemical solution deposition and rapid thermal processing. The phase and microstructure of the deposited films were studied as a function of sintering temperature, employing X-ray diffractometry and scanning electron microscopy. Dielectric properties of the films were measured at room temperature using impedance spectroscopy. Polycrystalline pure phase CCTO thin films with (220) preferential orientation was obtained at a sintering temperature of 750°C. There was a bimodal size distribution of grains. The dielectric constant and loss factor at 1 kHz obtained for a film sintered at 750°C was k <126> 2000 and tan δ<126> 0-05.

ref

020114   Sahoo A;Sarkar S;R Krishna P S;Joarder R N (Physics Dep, Jadavpur Univ, Kolkata-700 032, Email: rnjoarder09@yahoo.com ) : Molecular conformation and liquid structure of 2-propanol through neutron diffraction. Pramana J Phys 2010, 74(5), 765-79.

The neutron diffraction data analysis of deuterated liquid 2-propanol at room temperature to define its molecular conformation is presented. 2-Propanol being a large molecule with twelve atomic sites, the conformation analysis is tricky and an improved method of data analysis is given. The intermolecular structural correlations, i.e., hydrogen-bonded liquid structure, can be modelled accurately to extract the nature of the average hydrogen-bonded molecular association in liquid state at room temperature. Like other alcohols these are mostly hexamer ring chain (HRC) clusters. The cluster analysis of recent X-ray data available in the literature also support the same liquid structure.

8 illus, 2 tables, 23 ref

020113   Sabharwal S C;Jha S N; (Spectroscopy Division and Crystal Technology Laboratory, TPPED, Bhabha Atomic Research Centre, Mumbai-400 085, Email: sangita@barc.gov.in) : Optical and X-ray photoelectron spectroscopy of PbGeO₃ and Pb₅Ge₃O₁₁ single crystals. Bull Mater Sci 2010, 33(4), 395-400.

Pb₅Ge₃O₁₁ crystals are found to exhibit pale yellow colouration while PbGeO₃ are colourless. X-ray photoelectron spectroscopy (XPS) measurements show lead deficiency in both the crystals. The results also reveal a stronger ionic character for PbGeO₃ as compared to Pb₅Ge₃O₁₁ crystal. The binding energy of Ge3d core level in the case of Pb₅Ge₃O₁₁ crystal is found to be smaller than the binding energy of germanium oxide, thereby indicating the incomplete oxidation of Ge ions in the crystal lattice. On gamma ray irradiation, the transmission of both the crystals is observed to deteriorate uniformly over the entire wavelength range, which has been attributed to the oxidation of some of the lattice Pb ions. On gamma irradiation the changes observed in 01s core level energies for both the crystals are seen to be consistent with the changes noted in the Pb4f_7/2 and Ge3d spectra. Interestingly, the results reveal oxidation of surface Ge atoms with atmospheric oxygen under gamma irradiation.

9 illus, 1 table, 22 ref