017019   Kumar V;Shrivastava A K;Sinha A;Jha V (Electronics Engineering Dep, Indian School of Mines, Dhanbad-826 004, Email: vkumar52@hotmail.com) : Dielectric properties of different materials. Indian J pure appl Phys 2013, 51(1), 49-54.

Using the plasma oscillation theory of solids, simple relations have been proposed for the calculation of the homopolar (E_h), heteropolar (E_c) and average energy (E_g) gaps, ionicity (f_i) and dielectric constant (ε) of II-VI (R,W, Zb), III-V (W, Zb) and I-VII (R) groups of materials with rocksalt (R), wurtzite (W) and zincblende (Zb) structures from their plasmon energy (hω_p). The calculated values of E_h, E_c, E_g f_i and ε are compared with the experimental values and the values reported by earlier researchers. A fairly good agreement has been obtained between them.

4 illus, 3 tables, 39 ref

017018   Kocis L (NO, Peranga Court Unit 4, 43 Fifth Avenue, Sandgate, Queensland 4017, Australia, Email: l_kocis@hotmail.com) : Equations of motion for a relativistic wave packet. Pramana J Phys 2012, 78(5), 679-85.

The time derivative of the position of a relativistic wave packet is evaluated. It is found that it is equal to the mean value of the momentum of the wave packet divided by the mass of the particle. The equation derived represents a relativistic version of the second Ehrenfest theorem.

4 ref

017017   Katore S D;Adhav K S;Mete V G;Shaikh A Y (Mathematics Dep, S.G.B. Amravati Univ, Amravati-444 602, Email: katrosed@rediffmail.com) : Higher-dimensional Bianchi type-I inflationary universe in general relativity. Pramana J Phys 2012, 78(1), 101-7.

A five-dimensional Bianchi type-I inflationary Universe is investigated in the presence of massless scalar field with a flat potential. To get an inflationary Universe, a flat region in which the potential V is constant is considered. Some physical and kinematical properties of the Universe are also discussed.

29 ref

017016   Kamal N K (The Institute of Mathematical Sciences, CIT Campus, Chennai-600 113, Email: neeraj@imsc.res.in) : Pattern formation in arrays of chemical oscillators. Pramana J Phys 2012, 78(5), 705-18.

Describes a simple model mimicking diffusively coupled chemical micro-oscillators. Authors characterize the rich variety of dynamical states emerging from the model under variation of time delay in coupling, coupling strength and boundary conditions. The spatiotemporal patterns obtained include clustering, mixed dynamics, inhomogeneous steady states and amplitude death. Further, under delay in coupling, the model yields transitions from phase to antiphase oscillations, reminiscent of that observed in experiments.

9 illus, 23 ref

017015   Kakavand T;Aref M;Rajabifar S;Razavi R (Physics Dep, Zanjan Branch, Islamic Azad Univ, Zanjan, Iran, Email: Tayeb@znu.ac.ir) : Cyclotron production of <. Indian J pure appl Phys 2013, 51(1), 7-10.

^94mTc is an important positron-emitting radionuclide for Positron Emission Tomography (PET). ^94mTc has been produced using the ⁹⁴Mo (p, n) ^94mTc nuclear reaction by Cyclotron (Cyclone-30, IBA, Belgium) at the Agricultural, Medical and Industrial Research School (AMIRS). Deposition of MoO₃ on Cu substrate was carried out via two special sedimentation methods for the production of ^94mTc. The natural molybdenum target has been irradiated with a 15 MeV proton beam and the production yield is measured as 341.8+47.9 MBq/μAh. The comparison of present experimental result with calculation data (TALYS-1.0 code result) is shown that the pre-equilibrium particle emission of ^94mTc is described using the two-component Exciton model.

1 illus, 6 tables, 22 ref

017014   Jain A;Suneel Kumar (School of Physics and Materials Science, Thapar Univ, Patiala-147 004, Email: suneel.kumar@thapar.edu) : Effect of isospin-dependent cross-section on fragment production in the collision of charge asymmetric nuclei. Pramana J Phys 2012, 78(5), 749-58.

To understand the role of isospin effects on fragmentation due to the collisions of charge asymmetric nuclei, we have performed a complete systematical study using isospin-dependent quantum molecular dynamics model. Here simulations have been carried out for ¹²⁴X_n + ¹²⁴X_n, where n varies from 47 to 59 and for ⁴⁰Y_m + ⁴⁰Y_m, where m varies from 14 to 23. Study shows that isospin-dependent cross-section shows its influence on fragmentation in the collision of neutron-rich nuclei.

4 illus, 22 ref

017013   Ilamaran C;Sethuram M;Dhandapani M; Amrithaganesan G (Post Graduate and Research Chemistry Dep, Sri Ramakrishna Mission Vidyalaya, College of Arts and Science, Coimbatore-641 020, Email: srmvdhandapani@gmail.com) : Crystal growth, FTIR and thermal characterization of bis(ethyltriphenylphosphonium) tetrabromomanganate(II) dihydrate crystals. Pramana J Phys 2012, 78(5), 791-801.

Single crystals of a novel compound, bis(ethyltriphenylphosphonium) tetrabromoman-ganate(II) dihydrate (BTP-Mn) were grown by solution growth-slow evaporation technique from aqueous solution of the compound at ambient temperature. The grown crystals were characterized by elemental analysis, powder X-ray diffraction, thermal analysis, nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infra-red spectroscopy (FTIR) techniques. The chemical composition of the compound was revealed by elemental analysis and its crystallinity was confirmed by powder X-ray diffraction. Thermal analysis confirmed that the compound was stable up to 125°C. The various kinds of protons and carbons present in the compound were confirmed by ¹H NMR and ¹³C NMR technique respectively and the presence of phosphorous was confirmed by ³¹p NMR spectrum in the compound. The modes of vibration of different molecular groups present in the compound were identified by FTIR spectral analysis. The second harmonic genyation behaviour was tested by Nd:YAG laser source.

9 illus, 2 tables, 17 ref

017012   Hamoudi A K;Hasan M A;Ridha A R (Physics Dep, College of Science, Baghdad Univ, Baghdad, Iraq, Email: marwan.a.hasan@gmail.com) : Nucleon momentum distributions and elastic electron scattering form factors for some 1p-shell nuclei. Pramana J Phys 2012, 78(5), 737-48.

The nucleon momentum distributions (NMD) and elastic electron scattering form factors of the ground state for 1p-shell nuclei with Z = N (such as ⁶Li, ¹⁰B, ¹²C and ¹⁴N nuclei) have been calculated in the framework of the coherent density fluctuation model (CDFM) and expressed in terms of the weight function |f(x)|². The weight function has been expressed in terms of nucleon density distribution (NDD) of the nuclei and determined from the theory and the experiment. The feature of the long-tail behaviour at high-momentum region of the NMDs has been obtained by both the theoretical and experimental weight functions. The experimental form factors F(q) of all the considered nuclei are very well reproduced by the present calculations for all values of momentum transfer q. It is found that the contributions of the quadrupole form factors F_c2(q) in ¹⁰B and ¹⁴N nuclei, which are described by the undeformed p-shell model, are essential for obtaining a remarkable agreement between the theoretical and experimental form factors.

4 illus, 1 table, 38 ref

017011   Gosain D S;Somorendro Singh S;Jha A K (Physics and Astrophysics Dep, Delhi Univ, Delhi-110 007, Email: dharmender.gosain@gmail.com) : Nucleation rate of the quark-gluon plasma droplet at finite quark chemical potential. Pramana J Phys 2012, 78(5), 719-28.

The nucleation rate of quark-gluon plasma (QGP) droplet is computed at finite quark chemical potential. In the course of computing the nucleation rate, the finite size effects of the QGP droplet are taken into account. We consider the phenomenological flow parameter of quarks and gluons, which is dependent on quark chemical potential and we calculate the nucleation rate of the QGP droplet with this parameter. While calculating the nucleation rate, we find that for low values of quark phenomenological parameter γ_q, nucleation rate is negligible and when γ_q increases, nucleation rate increases significantly.

6 illus, 13 ref

017010   Ghosh B;Swarniv Chandra;Paul S N (Physics Dep, Jadavpur Univ, Kolkata-700 032, Email: bsdvghosh@gmail.com) : Relativistic effects on the modulational instability of electron plasma waves in quantum plasma. Pramana J Phys 2012, 78(5), 779-90.

Relativistic effects on the linear and nonlinear properties of electron plasma waves are investigated using the one-dimensional quantum hydrodynamic (QHD) model for a two-component electron-ion dense quantum plasma. Using standard perturbation technique, a nonlinear Schrodinger equation (NLSE) containing both relativistic and quantum effects has been derived. This equation has been used to discuss the modulational instability of the wave. Through numerical calculations it is shown that relativistic effects significantly change the linear dispersion character of the wave. Unlike quantum effects, relativistic effects are shown to reduce the instability growth rate of electron plasma waves.

3 illus, 37 ref

017009   Gaillard M K (Center for Theoretical Physics, Physics Dep, Theoretical Physics Group, Lawrence Berkeley National Laboratory, Berk, USA, Email: mkgaillard@ibl.gov) : BRST invariant PV regularization of SUSY Yang-mills and SUGRA. Pramana J Phys 2012, 78(6), 875-90.

Pauli-Villars regularization of Yang-Mills theories and of supergravity theories is outlined, with an emphasis on BRST invariance. Applications to phenomenology and the anomaly structure of supergravity are discussed.

1 illus, 38 ref

017008   Frohlich J;Gang Z (Theoretische Physik, ETH Zurich, CH-8093 Zurich, Switzerland, Email: juerg@itp.phys.ethz.ch) : On the theory of slowing down gracefully. Pramana J Phys 2012, 78(6), 865-74.

Discussed the transport of a tracer particle through the Bose-Einstein condensate of a Bose gas. The particle interacts with the atoms in the Bose gas through two-body interactions. In the limiting regime where the particle is very heavy and the Bose gas is very dense, but very weakly interacting ('mean-field limit'), the dynamics of this system corresponds to classical Hamiltonian dynamics. Shows that, in this limit, the particle is decelerated by emission of gapless modes into the condensate (Cerenkov radiation). For an ideal gas, the particle eventually comes to rest. In an interacting Bose gas, the particle is decelerated until its speed equals the propagation speed of the Goldstone modes of the condensate. This is a model of 'Hamiltonian friction'. It is also of interest in connection with the phenomenon of 'decoherence' in quantum mechanics. This note is based on work we have carried out in collaboration with D Egli, I M Sigal and A Soffer.

1 illus, 9 ref

017007   Ferrara S;Marrani A (Physics Dep, Theory Unit, CERN, CH-1211, Geneve 23, Switzerland, Email: sergio.ferrara@cern.ch ) : Black holes and groups of type E₇. Pramana J Phys 2012, 78(6), 893-905.

Reports some results on the relation between extremal black holes in locally super-symmetric theories of gravity and groups of type E₇, appearing as generalized electric-magnetic duality symmetries in such theories. Some basics on the covariant approach to the stratification of the relevant symplectic representation are reviewed, along with a connection between special Ka'hler geometry and a 'generalization' of groups of type E₇.

2 tables, 64 ref

017006   Epstein H (Institut des Hautes Etudes Scientifiques, 91440 Bures-sur-Yvette, France, Email: epstein@ihes.fr) : Remarks on quantum field theory on de Sitter and anti-de Sitter space-times. Pramana J Phys 2012, 78(6), 853-64.

This is a short review of work done in common with Jacques Bros, Michel Gaudin, Ugo Moschella, and Vincent Pasquier. Among results are explicit Kallen-Lehmann representations for products of two free-field two-point functions in the de Sitter and the anti-de Sitter spaces and applications to particle decay.

21 ref

017005   Dubois-Violette M (Laboratorie de Physique Theorique, CNRS UMR 8627, Paris Sud 11 Univ, Batiment 210, F-91 405 Orsay Cedex, France, Email: Michel.Dubois-Violette@u-psud.fr) : From Koszul duality to Poincare duality. Pramana J Phys 2012, 78(6), 947-61.

Discussed the notion of Poincare duality for graded algebras and its connections with the Koszul duality for quadratic Koszul algebras. The relevance of the Poincare duality is pointed out for the existence of twisted potentials associated to Koszul algebras as well as for the extraction of a good generalization of Lie algebras among the quadratic-linear algebras.

37 ref

017004   de Rujula A (Physics Dep, CERN, CH-1211, Geneve 23, Switzerland, Email: alvaro.derejula@cern.ch) : Charting the invisible in phase space. Pramana J Phys 2012, 78(6), 891.

One challenge in particle physics is that not all the momenta relevant to many processes are observable. Some particles are nearly invisible (neutrinos and hypothetical neutralinos), others escape undetected down the beam pipes of colliders. One faces the task of extracting the maximum information (e.g. on the mass of the unobserved particles) from a set of more unknowns than constraining energy-momentum conservation equations. Study the simplest realistic case of current interest: single- W production at a hadron collider, followed by its leptonic decay. Derives and discusses the statistically-optimal 'singularity variable' relevant to the measurement of the W mass. In spite of its simplicity, this process is fairly non-trivial and constitutes a good 'training' example for the scrutiny of phenomena involving invisible objects. Graphical analysis of the phase space is akin to that of a Dalitz plot, extended to such processes.

ref

017003   De Rafael E (Centre de Physique Theorique, Unite Mixte de Recherche (UMR 6207) du CNRS et des Aix Marseille 1 Un, Aix Marseille 2 et Sud Toulon-Var, affilee a la Frumam, CNRS-Luminy, Case 907, F-13288 Marseille Cedex 9, France, Email: EdeR@cpt.univ-mrs.fr) : Large-N_c quantum chromodynamics and harmonic sums. Pramana J Phys 2012, 78(6), 927-46.

In the large-N_c limit of QCD, two-point functions of local operators become harmonic sums. Reviews some properties which follow from this fact and which are relevant for phenomeno-logical applications. This has led us to consider a class of analytic number theory functions as toy models of large-N_c QCD which also is discussed.

6 illus, 44 ref

017002   Bera P K (Physics Dep, Dumkal College, Basantapur, Dumkal, Murshidabad-742 303, Email: pkbdcb@gmail.com) : Exact solutions for the interaction V(r) = αr<. Pramana J Phys 2012, 78(5), 667-77.

The exact solutions for the two- and N-dimensional Schrodinger equation have been rederived for the potential V(r) = αr^2d-2- βr^d-2 by Nikiforov-Uvarov method. Specific results are presented for (i) the hydrogen atom and (ii) an isotropic harmonic oscillator. The dimensionality of the problem is seen to enter into these relations in such a way that one can immediately verify the corresponding three-dimensional results. The local accidental degeneracies are also explained for the two- and N-dimensional problems.

33 ref

017001   Bera P K (Physics Dep, Dumkal College, Basantpur, Dumkal, Murshidabad-742 303, Email: pkbdcb@gmail.com) : Approximate solutions of the Wei Hua oscillator using the Pekeris approximation and Nikiforov-Uvarov method. Pramana J Phys 2012, 78(1), 91-9.

The approximate analytical bound-state solutions of the Schrodinger equation for the Wei Hua oscillator are carried out in N-dimensional space by taking Pekeris approximation scheme to the orbital centrifugal term. Solutions of the corresponding hyper-radial equation are obtained using the conventional Nikiforov-Uvarov (NU) method.

35 ref

017000   Becchi C M (Physics Dep, Genova and INFN Sezione di Genova Univ, via Dodecaneso 33, I-1622 Genova, Italy, Email: becchi@ge.infn.it) : BRS 'symmetry', prehistory and history. Pramana J Phys 2012, 78(6), 837-51.

Prehistory - Starting from 't Hooft's (1971) we have a short look at Taylor's and Slavnov's works (1971-72) and at the lectures given by Rouet and Stora in Lausanne (1973) which determine the transition from pre-history to history. History - We give a brief account of the main analyses and results of the BRS collaboration concerning the renormalized gauge theories, in particular the method of the regularization-independent, algebraic renormalization, the algebraic proof of S-matrix unitarity and that of gauge choice independence of the renormalized physics. We conclude this report with a suggestion to the crucial question: what could remain of BRS invariance beyond perturbation theory.

27 ref

016999   Aydogu S;Akarsu M;Ozbas O (Physics Dep, Dumulupinar Univ, Kutahya, Turkey, Email: aydou@yahoo.com) : Theoretical calculation of the Hall mobility of InN_xAs_1-x alloys when x = 0.0-0.1. Pramana J Phys 2012, 78(1), 147-54.

The Hall mobility of InN_xAs_1-x semiconductor alloys is calculated by solving the Boltzmann transport equation using the iterative method. All the major scattering mechanisms are included in the calculations. The Hall mobilities of InAs and InNg_0.01 Aso.99 are presented in the temperature range of 30-600 K. It is shown that incorporation of even small amount of nitrogen leads to an abrupt reduction of the Hall mobility in InN_xAs_1-x at low temperatures. The effect of alloy random scattering on the Hall mobility of InN_x As_1-x is examined at 77 and 300 K as the mole fraction x varies from 0.0 to 0.1. It is seen that the Hall mobility drops sharply up to x = 0.02 for 77 K and reduces slowly as the temperature increases to 300 K compared to 77 K. The Hall mobilities calculated theoretically are compared with the experimental data available in the literature.

3 illus, 1 table, 47 ref

016998   Annou K;Annou R (Theoretical Physics Laboratory, Faculty of Physics, USTHB BP 32, El Alia, Bab-Ezzour, Algiers, Algeria, Email: annoukarima@yahoo.fr) : Effect of nonthermal ion distribution and dust temperature on nonlinear dust-acoustic solitary waves. Pramana J Phys 2012, 78(1), 121-6.

Dust-acoustic solitary waves in unmagnetized dusty plasma whose constituents are iner-tial charged dust grains, Boltzmannian electrons and nonthermal ions have been investigated by taking into account finite dust temperature. The pseudopotential has been used to study solitary solution. The existence of solitary waves having negative potential is reported.

5 illus, 9 ref

016997   Angesh Chandra;Archana Chandra;Thakur K (Applied Physics Dep, Shri Shankaracharya Institute of Prof. Managament & Technology, Raipur-492 015, Email: chandrassi@gmail.com) : Preparation and characterization of hot-pressed Na<. Indian J pure appl Phys 2013, 51(1), 44-8.

Preparation and characterization of hot-pressed Na⁺ ion conducting nano-composite polymer electrolytes (NCPEs): (1-x) [70PEO:30NaClO₄] + xSiO₂, where x in wet.%, are reported. These NCPEs were casted by solvent-free/hot-press method. The composition dependent conductivity studies at room temperature revealed that the composition: 93 [70PEO: 30NaClO₄] + 7 SiO₂ has the highest conductivity (σ <126> 7.6 x 10^-6 S.cm^-1). This has been referred to as Optimum Conducting Composition (OCC). Materials characterization and polymer-salt complexation have been explained with the help of SEM, FTIR, DSC and TGA analysis.

7 illus, 1 table, 21 ref

016048   Zhou B;Zhebng M Y;Wen D Y (Physics Lab, Nanxu College, Jiangsu Science and Technology Univ, Zhenjiang, Jiangsu-212 003, People's Republic of China, Email: binzhou@mail.ustc.edu.cn) : Second born approximation of electron-argon elastic scattering in a bichromatic laser field. Pramana J Phys 2012, 78(3), 399-404.

We study the elastic scattering of atomic argon by electron in the presence of a bichro-matic laser field in the second Born approximation. The target atom is approximated by a simple screening potential and the continuum states of the impinging and emitting electrons are described as Volkov states. We evaluate the S-matrix elements numerically. The dependence of differential cross-section on the relative phase between the two laser components is presented. The results obtained in the first and second Born approximations are compared and analysed.

3 illus, 19 ref

016047   Zhang Z H;Wu S Y;Zhang S X;Li L L (Applied Physics Dep, Electronic Science and Technology of China Univ, Chengdu-610 054, People's Republic of China, Email: shaoyi_wu@163.com) : Theoretical studies of the g factors and local structure for Pt<. Pramana J Phys 2012, 78(3), 475-82.

The anisotropic g factors and local structure for the trigonal Pt³⁺ centre in α-Al₂O₃ are theoretically investigated from the perturbation formulas of the g factors for a 5d⁷ ion in trigonal symmetry. The Pt³⁺ impurity is found to experience an outward displacement by about 0.18 A away from the centre of the oxygen octahedron along the C₃-axis. The calculated g factors based on the above axial displacement show good agreement with the observed values. Importantly, the pending problem of +3 valence state of the doped Pt in α-Al₂O₃ is theoretically clarified, and the possibility of Pt⁺ (5d⁹) is thus excluded in this work.

1 table, 36 ref

016046   Zhang Y;Lu K;Guo J;Long X;Hu X;Li K (State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academic of Sciences, Xi'an-710 119, China, Email: zhangyh1979@163.com) : Formation of multiple dark photovoltaic spatial solitons. Pramana J Phys 2012, 78(2), 265-75.

Theoretically study the formation of multiple dark photovoltaic soliton splitting in the quasi-steady-state and steady-state regimes under open-circuit conditions and find that the initial width of the dark notch at the entrance face of the crystal is a key parameter for generating an even (or odd) number sequence of dark coherent photovoltaic solitons. If the initial width of the dark notch is small, only a fundamental soliton or Y-junction soliton pair is generated. As the initial width of the dark notch is increased, the dark notch tends to split into an odd (or even) number of multiple dark photovoltaic solitons, which realizes a progressive transition from a low-order soliton to a sequence of higher-order solitons. The soliton pairs far away from the centre have bigger width and less visibility. In addition, when the distance from the centre of the dark notch increases, the separations between adjacent dark stripes become slightly smaller.

7 illus, 28 ref

016045   Tanisli M;Jancewicz B (Anadolu Univ, Science Faculty, Physics Dep, 26470, Eskisehir, Turkey, Email: mtanisli@anadolu.edu.tr) : Octonionic lorenz-like condition. Pramana J Phys 2012, 78(2), 165-74.

In this study, the octonion algebra and its general properties are defined by the Cayley-Dickson's multiplication rules for octonion units. The field equations, potential equations and Maxwell equations for electromagnetism are investigated with the octonionic equations and these equations can be compared with their vectorial representations. The potential and wave equations for fields with sources are also provided. By using Maxwell equations, a Lorenz-like condition is newly suggested for electromagnetism. The existing equations including the photon mass provide the most acknowledged Lorenz condition for the magnetic monopole and the source.

1 table, 23 ref

016044   Tahir M;Bhattacharya K;Chakraborty A K (NO, Jhikra High School (H.S.), Jhikra, Joypur, Howrah-711 401, Email: mail2mdtahir@gmail.com) : Vector wave diffraction pattern of slits masked by polarizing devices. Pramana J Phys 2012, 78(3), 405-16.

Polarization property is important to the optical imaging system. It has recently been understood that the polarization properties of light can be fruitfully used for improving the characteristics of imaging system that includes polarizing devices. The vector wave imagery lends an additional degree of freedom that can be utilized for obtaining results that are unobtainable in scalar wave imagery. This calls for a systematic study of diffraction properties of different apertures using polarization-sensitive devices. In the present paper, we have studied the Fraunhofer diffraction pattern of slits masked by different kinds of polarizing devices which introduce a phase difference between the two orthogonal components of the incident beam.

5 illus, 11 ref

016043   Tabbakh F;Aldaavati M M;Hoseyni M S;Rezaee K; Saraee E (NO, Institute of Nuclear Science and Technology, P.O.Box 14395-836, Tehran, Iran, Email: ftabbakh@aeoi.org.ir) : Induced photonuclear interaction by rhodotron-TT200 10MeV electron beam. Pramana J Phys 2012, 78(2), 257-64.

In this paper the photonuclear interaction induced by 10 MeV electron beam generating high-intensity neutrons is studied. Since the results depend on the target material, the calculations are performed for Pb, Ta and W targets which have high Z, in a simple geometry. MCNPX code has been used to simulate the whole process. Also, the results of photon generation has been compared with the experimental results to evaluate the reliability of the calculation. The results show that the obtained neutron flux can reach up to 10¹² n/cm²/s with average energies of 0.9 MeV, 0.4 MeV and 0.9 MeV for these three elements respectively with the maximum heat deposited as 3000 W/c³, 4500 W/c³and 6000 W/c³.

8 illus, 1 table, 13 ref

016042   Song Y L;Lu D B;Cui B L;Zhang J M (College of Physics and Information Technology, ShaanXi Normal Univ, Xian, ShaanXi-710 062, China, Email: dblu985@163.com) : Electronic structures of the F-terminated A1N nanoribbons. Pramana J Phys 2012, 78(3), 469-74.

Using the first-principles calculations, electronic properties for the F-terminated A1N nanoribbons with both zigzag and armchair edges are studied. The results show that both the zigzag and armchair A1N nanoribbons are semiconducting and nonmagnetic, and the indirect band gap of the zigzag A1N nanoribbons and the direct band gap of the armchair ones decrease monotonically with increasing ribbon width. In contrast, the F-terminated A1N nanoribbons have narrower band gaps than those of the H-terminated ones when the ribbons have the same bandwidth. The density-of-states (DOS) and local density-of-states (LDOS) analyses show that the top of the valence band for the F-terminated ribbons is mainly contributed by N atoms, while at the side of the conduction band, the total DOS is mainly contributed by Al atoms. The charge density contour analyses show that Al-F bond is ionic because the electronegativity of F atom is much stronger for F atom than for Al atom, while N-F bond is covalent because of the combined action of the stronger electronegativity and the smaller covalent radius.

5 illus, 23 ref

016041   Shukla S;Kumar S (Physics Dep, Christ Church College, Kanpur-208 001, Email: dr_santosh_kr@yahoo.com) : Optical characterization of a-Se₈₅-xTe₁₅Znx thin films. Pramana J Phys 2012, 78(2), 309-18.

Thin films of Se_85-xTe₁₅Zn_x(x = 0, 2, 4,6 and 10) glassy alloys have been deposited onto a chemically cleaned glass substrate by thermal evaporation technique under vacuum. The analysis of transmission spectra, measured at normal incidence, in the spectral range of 400-2500 nm helped us in the optical characterization of thin films under study. From the analysis of transmission spectra, the optical parameters such as refractive index (n), extinction coefficient (k), absorption coefficient (a), real and imaginary dielectric constants (χ' and χ) have been calculated. It is observed that the parameters n, k, χ', χ and a decrease with increase in wavelength (λ) and increase with Zn content. Optical band gap (E_g) has also been calculated and found to decrease with Zn content in Se_85-xTe₁₅Zn_x glassy system which could be correlated with increase in the density of defect states.

8 illus, 2 tables, 27 ref

016040   Shinde M N;Talware R B;Hudge P G;Joshi Y S; Kumbharkhane A C (School of Physical Sciences, Swami Ramanand Teerth Marathwada Univ, Nanded-431 606, Email: akumbharkhane@yahoo.co.in) : Dielectric relaxation and hydrogen bonding studies of 1,3-propanediol-dioxane mixtures using time domain reflectometry technique. Pramana J Phys 2012, 78(2), 297-308.

Complex permittivity, static dielectric constant and relaxation time for 1,3-propanediol, 1,4-dioxane and their mixtures have been studied using time domain reflectometry (TDR). The excess permittivity, excess inverse relaxation time and Kirk wood correlation factor have also been determined at various concentrations of dioxane. Hydrogen bonded theory was applied to compute the correlation terms for the mixtures. The Bruggeman model for the nonlinear case has been fitted to the dielectric data for mixtures.

9 illus, 1 table, 52 ref

016039   Sharma N K (Physics Dep, Jaypee Institute of Information Technology, A-10, Sector-62, Noida-201 307, Email: navneetk.sharma@jiit.ac.in) : Performances of different metals in optical fibre-based surface plasmon resonance sensor. Pramana J Phys 2012, 78(3), 417-27.

The capability of various metals used in optical fibre-based surface plasmon resonance (SPR) sensing is studied theoretically. Four metals, gold (Au), silver (Ag), copper (Cu) and aluminium (Al) are considered for the present study. The performance of the optical fibre-based SPR sensor with four different metals is obtained numerically and compared in detail. The performance of optical fibre-based SPR sensor has been analysed in terms of sensitivity, signal-to-noise (SNR) ratio and quality parameter. It is found that the performance of optical fibre-based SPR sensor with Au metal is better than that of the other three metals. The sensitivity of the optical fibre-based SPR sensor with 50 nm thick and 10 mm long Au metal film of exposed sensing region is 2.373 μm/RIU with good linearity, SNR is 0.724 and quality parameter is 48.281 RIU^-1. The thickness of the metal film and the length of the exposed sensing region of the optical fibre-based SPR sensor for each metal are also optimized.

3 illus, 4 tables, 18 ref

016038   Saini R;Ashokan V;Indu B D;Kumar R (Physics Dep, Gurukula Kangri Vishwavidyalaya, Haridwar-249 404, Email: drbdindu@gmail.com) : Phonon heat transport in gallium arsenide. Pramana J Phys 2012, 78(3), 459-68.

The lifetimes of quantum excitations are directly related to the electron and phonon energy linewidths of a particular scattering event. Using the versatile double time thermodynamic Green's function approach based on many-body theory, an ab-initio formulation of relaxation times of various contributing processes has been investigated with newer understanding in terms of the linewidths of electrons and phonons. The energy linewidth is found to be an extremely sensitive quantity in the transport phenomena of crystalline solids as a collection of large number of scattering processes, namely, boundary scattering, impurity scattering, multiphonon scattering, interference scattering, electron-phonon processes and resonance scattering. The lattice thermal conductivities of three samples of GaAs have been analysed on the basis of modified Callaway model and a fairly good agreement between theory and experimental observations has been reported.

7 illus, 1 table, 51 ref

016037   Sahu M K (Physics of Sound Dep, Indira Kala Sangit Vishwavidyalaya, Khairagarh, Chhattisgarh) : Luminescence properties of semiconductor nanoparticles. Nano Vision 2013, 3(1), 1-4.

Luminescence studies in nanostructures is a current topic of research In low dimensional systems electron and holes are spatially confined causing quantum confinement effects. It has been found that the efficiency and Stokes shift of low dimensional system increases with decreasing size R of the semiconductor nanoparticles. It has been found that the size-dependence of the luminescence efficiency η and makes a comparison between the theoretical experimental values of η.

2 illus, 6 ref

016036   Ravichandran V;Chinnathambi V;Rajasekar S (Physics Dep, Sri K.G.S. Arts College, Srivaikuntam-628 619, Email: v_chin2005@yahoo.com) : Nonlinear resonance in duffing oscillator with fixed and integrative time-delayed feddbacks. Pramana J Phys 2012, 78(3), 347-60.

Study the nonlinear resonance, one of the fundamental phenomena in nonlinear oscillators, in a damped and periodically-driven Duffing oscillator with two types of time-delayed feedbacks, namely, fixed and integrative. Particularly, we analyse the effect of the time-delay parameter a and the strength γ of the time-delayed feedback. Applying the perturbation theory we obtain a nonlinear equation for the amplitude of the periodic response of the system. For a range of values of γ and α, the response amplitude is found to be higher than that of the system in the absence of delayed feedback. The response amplitude is periodic on the parameter a with period 2π(<128><119> where <128><119> is the angular frequency of the external periodic force. Shows the occurrence of multiple branches of the response amplitude curve with and without hysteresis.

13 illus, 31 ref

016035   Pande R;Roy S;Rao S V L S;Singh P;Kailas S (Physics Group, Bhabha Atomic Research Centre, Mumbai-400 085, Email: pande_rajni@rediffmail.com) : Physics design of a CW high-power proton linac for accelerator-driven system. Pramana J Phys 2012, 78(2), 247-55.

Accelerator-driven systems (ADS) have evoked lot of interest the world over because of their capability to incinerate the MA (minor actinides) and LLFP (long-lived fission products) radiotoxic waste and their ability to utilize thorium as an alternative nuclear fuel. One of the main subsystems of ADS is a high energy (~1 GeV) and high current (~30 mA) CW proton Linac. The accelerator for ADS should have high efficiency and reliability and very low beam losses to allow hands-on maintenance. With these criteria, the beam dynamics simulations for a 1 GeV, 30 mA proton Linac has been done. The Linac consists of normal-conducting radio-frequency quadrupole (RFQ), drift tube linac (DTL) and coupled cavity drift tube Linac (CCDTL) structures that accelerate the beam to about 100 MeV followed by superconducting (SC) elliptical cavities, which accelerate the beam from 100 MeV to 1 GeV. The details of the design are presented in this paper.

6 illus, 3 tables, 15 ref

016034   Om Prakash;Devendra Kumar;Dwivedi Y K (Mathematics Dep, Hindustan College of Science & Technology, Farah Mathura-281 112, Email: o_ibs@rediffmail.com) : Free convection effects and radiative heat transfer in MHD stokes problem for the flow of dusty conducting fluid through prorous medium. Pramana J Phys 2012, 78(3), 429-38.

The present note deals with the effects of radiative heat transfer and free convection in MHD for a flow of an electrically conducting, incompressible, dusty viscous fluid past an impulsively started vertical non-conducting plate, under the influence of transversely applied magnetic field. The heat due to viscous dissipation and induced magnetic field is assumed to be negligible. The governing linear partial differential equations are solved by finite difference technique. The effects of various parameters (like radiation parameter N, Prandtl number Pr, porosity parameter K) entering into the MHD Stokes problem for flow of dusty conducting fluid have been examined on the temperature field and velocity profile for both the dusty fluid and dust particles.

12 illus, 15 ref

016033   Niranjan R S;Rudraswamy B;Dhananjaya N (Physics Dep, Bangalore Univ, Bangalore-560 056, Email: dhanu.siri@yahoo.co.in) : Effective atomic number, electron density and kerma of gamma radiation for oxides of lanthanides. Pramana J Phys 2012, 78(3), 451-8.

An attempt has been made to estimate the effective atomic number, electron density (0.001 to 10⁵ MeV) and kerma (0.001 to 20 MeV) of gamma radiation for a wide range of oxides of lanthanides using mass attenuation coefficient from WinXCom and mass energy absorption coefficient from Hubbell and Seltzer. The values of these parameters have been found to change with energy for different oxides of lanthanides. The lanthanide oxides find remarkable applications in the field of medicine, biology, nuclear engineering and space technology. Nano-oxides of lanthanide find applications in display and lighting industry.

3 illus, 2 tables, 15 ref

016032   Liu S Q;Tang W;Li X Q (Physics Dep, Nanchang Univ, Nanchang-330 047, People's Republic of China, Email: sqlgroup@ncu.edu.cn) : Modulation instability of an intense laser beam in an unmagnetized electron-positron-ion plasma. Pramana J Phys 2012, 78(3), 439-49.

The modulation instability of an intense circularly polarized laser beam propagating in an unmagnetized, cold electron-positron-ion plasma is investigated. Adopting a generalized Karpman method, a three-dimensional nonlinear equation is shown to govern the laser field. Then the conditions for modulation instability and the temporal growth rate are obtained analytically. In order to compare with the usual electron-ion plasmas, the effect of positron concentration is considered. It is found that the increase in positron-to-electron density ratio shifts the instability region towards higher vertical wave numbers but does not cause displacement along the parallel wave number direction, and the growth rate increases as the positron-to-electron density ratio increases.

2 illus, 30 ref

016031   Khare A;Saxena A (NO, Institute of Physics, Sachivalaya Marg, Bhubaneswar-751 005, Email: khare@iiserpune.ac.in) : Solutions of several coupled discrete models in terms of Lame polynomials of order one and two. Pramana J Phys 2012, 78(2), 187-213.

Coupled discrete models abound in several areas of physics. Here we provide an extensive set of exact quasiperiodic solutions of a number of coupled discrete models in terms of Lame polynomials of order one and two. Some of the models discussed are: (i) coupled Salerno model, (ii) coupled Ablowitz-Ladik model, (iii) coupled saturated discrete nonlinear Schrodinger equation, (iv) coupled φ⁴ model and (v) coupled φ⁶ model. Furthermore, we show that most of these coupled models in fact also possess an even broader class of exact solutions.

35 ref

016030   Jain S R (Nuclear Physics Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: srjain@barc.gov.in ) : Origin in inertia in large-amplitude collective motion in finite fermi systems. Pramana J Phys 2012, 78(2), 225-30.

Authors argue that mass parameters appearing in the treatment of large-amplitude collective motion, be it fission or heavy-ion reactions, originate as a consequence of their relation with Lyapunov exponents coming from the classical dynamics, and, fractal dimension associated with diffusive modes coming from hydrodynamic description.

33 ref

016029   Jain R K;Ashok Kumar;Singh N L;Tommasino L; Singh B K (Physics Dep, School of Basic & Applied Sciences, Shobhit Univ, Meerut-250 110, Email: ashokblp@gmail.com) : Measurement of peak fluence of neutron beams using Bi-fisson detectors. Pramana J Phys 2012, 78(3), 493-8.

Fission fragments and other charged particles leave tracks of permanent damage in most of the insulating solids. Damage track detectors are useful for personal dosimeters and for flux/dose determination of high-energy particles from accelerators or cosmic rays. A detector that has its principal response at nucleon energy above 50 MeV is provided by the fission of Bi-209. Neutrons produce the largest percentage of hadron dose in most high-energy radiation fields. In these fields, the neutron spectrum is typically formed by low-energy neutrons (evaporation spectrum) and high-energy neutrons (knock-on spectrum). We used Bi-fission detectors to measure neutron peak fluence and compared the result with the calculated value of neutron peak fluence. For the exposure to 100 MeV we have used the iThemba Facility in South Africa.

3 illus, 1 table, 15 ref

016028   Jagadale B N;Hosamani G (Electronics Dep, Kuvempu Univ, Shankaragatta) : Preparation and characterization of semiconductor thin films. Nano Vision 2013, 3(1), 5-9.

The CdTe & ZnTe thin films of different thickness were prepared in the vacuum chamber using thermal evaporation using vacuum coating unit. The prepared films were cut into pieces and characterized for structural and optical properties. The structural analysis of as prepared samples was carried out by the XRD (PHILIPS PW 3710). The structural analysis showed that increase with thickness, crystallanity and grain size increases where as strain and dislocation density decreases. With increase in deposition time, the nucleus size increases leading to larger clusters, their coalescence and formation of continuous films and hence also the grain size of these films.

1 illus, 1 table, 6 ref

016027   Goyal M;Gupta B R K (Physics Dep, GLA Univ, Mathura) : Compressional and elastic behavior of nano-ZnO crystal at high pressure. Nano Vision 2013, 3(1), 29-35.

Authors have reported the results of a theoretical investigation on the compressional and elastic behavior of ZnO nanocrystal at high pressure during transformation from wurtzite to rock salt structure. A simple theory is proposed to predict the transition pressure (P_T) and bulk modulus of ZnO nanocrystal at high pressure which gets support from the Mie-Gruneisen theory of thermal expansivity as formulated by Born and Huang. We have considered the Tait's equation of state to study the effect of pressure on the phase transition from wurtzite (W) to rock salt (R) phase in zinc oxide nanomaterial. The results obtained are found to present a good agreement with the available experimental data. A good agreement between theoretical and experimental results demonstrates the validity of the equation of state used in the present study to explain the compressional behavior of nanomaterials at high pressure.

2 illus, 1 table, 24 ref

016026   Gautam S;Rajni Kant (Physics Dep, Punjab Univ, Chandigarh-160 014, Email: sakshigautm@gmail.com) : Fragmentation and momentum correlations in heavy-ion collisions. Pramana J Phys 2012, 78(3), 389-98.

The role of momentum correlations in the production of light and medium mass fragments is studied by imposing momentum cut in the clusterization of the phase space. Our detailed investigation shows that momentum cut has a major role to play in the emission of fragments. A comparison with the experimental data is also presented. The calculations showed better agreement with the experimental data when momentum cut is imposed.

8 illus, 15 ref

016025   Chen J;Li B (Mathematics Dep, Ningbo Univ, Ningbo-315 211, People's Republic of China, Email: junchaochen@yahoo.com.cn ) : Multiple (G'/G)-expansion method and its applications to nonlinear evolution equations in mathematical physics. Pramana J Phys 2012, 78(3), 375-88.

In this paper, an extended multiple (G'/G)-expansion method is proposed to seek exact solutions of nonlinear evolution equations. The validity and advantages of the proposed method is illustrated by its applications to the Sharma-Tasso-Olver equation, the sixth-order Ramani equation, the generalized shallow water wave equation, the Caudrey-Dodd-Gibbon-Sawada-Kotera equation, the sixth-order Boussinesq equation and the Hirota-Satsuma equations. As a result, various complexiton solutions consisting of hyperbolic functions, trigonometric functions, rational functions and their mixture with parameters are obtained. When some parameters are taken as special values, the known double solitary-like wave solutions are derived from the double hyperbolic function solution. In addition, this method can also be used to deal with some high-dimensional and variable coefficients' nonlinear evolution equations.

45 ref

016024   Chakrabarti S;Anantha Ramakrishna S (Physics Dep, Indian Institute of Technology-Kanpur, Kanpur-208 016, Email: sar@iitk.ac.in) : Magnetic response of split-ring resonator metamaterials: from effective medium dispersion to photonic band gaps. Pramana J Phys 2012, 78(3), 483-92.

On systematically investigating the electromagnetic response of periodic split-ring res-onator (SRR) metamaterials as a function of the size-to-wavelength (a/λ) ratio, we find that the stop bands due to the geometric resonances of the SRR weaken with increasing (a/λ) ratio, and are eventually replaced by stop bands due to Bragg scattering. Our study traces the behaviour of SRR-based metamaterials as the resonance frequency increases and the wavelength of the radiation finally becomes comparable to the size of the unit cell of the metamaterial. In the intermediate stages, the dispersion of the SRR metamaterial can still be described as due to a localized magnetic resonances while Bragg scattering finally becomes the dominant phenomenon as a/A ~ 1/2.

6 illus, 1 table, 17 ref

016023   Bhowmick S K;Ghosh N K (Physics Dep, Kalyani Univ, Kalyani-741 235, Email: nanda.ku@rediffmail.com) : Nonlocal coulomb interaction in the two-dimensional spin-1/2 falicov-kimball model. Pramana J Phys 2012, 78(2), 289-96.

Two-dimensional (2D) extended Falicov-Kimball model has been studied to observe the role of nonlocal Coulomb interaction (U_nd) using an exact diagonalization technique. The f-state occupation (n^f), the f-d intersite correlation function (c_fd), the specific heat (C), entropy (5) and the specific heat coefficient (γ) have been examined. Nonlocal Coulomb interaction-induced discontinuous insulator-to-metal transition occurs at a critical f-level energy. More ordered state is obtained with the increase of U_nc. In the specific heat curves, two-peak structure as well as a single-peak structure appears. At low-temperature region, a sharp rise in the specific heat coefficient γ is observed. The peak value of γ shifts to the higher temperature region with U_nc.

6 illus, 26 ref

016022   Bhaiswar J B;Salunkhe M Y;Dongre S P (Physics Dep, Institute of Science, Nagpur) : Synthesis, characterization and thermal, electrical study of CdS-polyaniline nanocomposite via oxidation polymerization. Nano Vision 2013, 3(1), 11-17.

Nanocomposites of conducting polyaniline with CdS nanoparticles have been synthesized via chemical Oxidation technique. The effect of CdS-nanoparticles on the electrical conductivity and thermal stability of polyaniline was discussed. The as prepared products were characterized by FT-IR, XRD and Transmission electron Microscopy and TGA thermogram. FTIR absorption band at 3600 - 3500 cm^-1 confirmed the highly attached polyaniline with CdS nanoparticles. The XRD study revealed the increased in crystalline nature of nanocomposite. TEM showed the CdS particles are in nanorange with the average diameter of 21 nm which was evenly distributed in polymer matrix. Thermo gravimetric analysis clearly indicated the increased in thermal stability of nanocomposite than the pure PANI. The uniform intercalation of CdS nanoparticles results in a co-operative phenomenon between the polyaniline and the nanoparticles, as a consequence, the CdS nanoparticles increased the electrical conductivity of polyaniline nanocomposite to 1.79x10^- S/cm compared to the pure polyaniline (10^-10 S/cm) and Silicon (10^{- 4}S/cm) semiconductors. Its electrical conductivity was found to be analogous with existing semiconducting metals. The fact is supported by the ample of experimental results and characterization evidences.

5 illus, 13 ref