019423   Sundaraganesan N;Elango G;Sebastian S; Subramani P (Physics (Engg.) Dep, Annamalai University, Annamalai Nagar-608 002, Email: sundaraganesan_n2003@yahoo.co.in) : Molecular structure, vibrational spectroscopic studies and analysis of 2-fluoro-5-methylbenzonitrile. Indian J pure appl Phys 2009, 47(7), 481-90.

Quantum mechanical calculations of energies, geometries and vibrational wavenumbers of 2-fluoro-5-methyl-benzonitrile (2F5MBN) have been carried out by using density functional theory (DFT/B3LYP) method with 6-311++G(d,p), cc-pvdz, Aug-cc-pvdz as basis sets. The optimized geometrical parameters obtained by DFT calculations are found to be in good agreement with experimental X-ray data. The best level of theory in order to reproduce the experimental wavenumbers is B3LYP method with the 6-311++G(d,p) basis set. The difference between the observed and scaled wavenumber values of most of the fundamentals is very small. A detailed interpretation of the infrared and Raman spectra of 2F5MBN has also been reported. The entropy of the compound under study is also performed at /B3LYP/ 6-311++G(d,p), cc-pvdz, Aug-cc-pvdz levels. The theoretical spectrogram for FT-IR and FT-Raman spectra of the molecule have been constructed.

019422   Srivastava V K;Bose S K (Physics Dep, DDU Gorakhpur University, Gorakhpur-273 009, Email: vijai_gkp71@yahoo.in) : Exact solution of relativistic Schrodinger equation for the central complex potential V(r) = iar + (b/r). Indian J pure appl Phys 2009, 47(8), 547-50.

A set of exact solutions of the relativistic Schr”dinger equation for the central complex potential V(r) = iar + (b/r), where a and b are parameters of the given potential, is obtained by using a suitable ansatz. The exact solution of such equation is found to be relevant in particle physics as well as in nuclear physics. The energy eigenvalue and corresponding eigenfunction are obtained for each solution. These solutions are valid, in general, when the interrelation between the parameters of the potential (a and b) and the orbital angular momentum quantum number l must be satisfied. These solutions, besides having an aesthetic appeal can be used as bench mark to test the accuracy and reliability of non-perturbative methods, which sometimes yield wrong results of solving the Schr”dinger equation.

019421   Srivastava R;Tiwari A;Khanna K N (Physics Dep, VSSD College, Kanpur, , Email: knkhanna@rediffmail.com) : Shear viscosity of dense fluid. Indian J pure appl Phys 2009, 47(8), 568-71.

Formula for the shear viscosity of square well fluids has been proposed through the modified pair correlation function in hard sphere system. The results are compared with the expression derived by Nigra and Evans for square well potential and with those derived from the diffusion coefficient of L-J potential by employing Stokes-Einstein relation. The numerical results of the scaling laws relating with the shear viscosity are also compared with the theoretical results.

019420   Sonekar R P;Omanwar S K;Moharil S V (Physics Dep, G. S. College, Khamgaon) : Combustion synthesis and photoluminescence of Eu<. Indian J pure appl Phys 2009, 47(6), 441-3.

The photoluminescence properties of inorganic borate host material BaB₈O₁₃ doped with Eu^{2+ have been studied. The material BaB₈O₁₃:Eu2+ was prepared by a novel technique which is a slight variation of solution combustion synthesis. The synthesis is based on the exothermic reaction between the fuel (urea) and oxidizer (ammonium nitrate). The structure of the prepared sample was confirmed by powder XRD technique and photoluminescence properties were investigated. Under UV excitation (254 nm), BaB₈O13: Eu2+ shows intense broad emission band peak at 408 nm. The effect of concentration of Eu2+ ions on the PL intensity has also been investigated. It has been observed that the powder sample exhibits highest PL emission intensity for Eu2+ concentration of about 0.03 moles.}

019419   Singh V;Tiwari M;Soni M;Aynayas M;Hyun S H; Kwak H Y;Natarajan V (Physics Dep, Bhoj College, Kotra, Bhopal-462 003, Email: vijayjiin2006@yahoo.com) : Photoluminescence and EPR investigation of combustion synthesized BaAl₂O₄:Cr<. Indian J pure appl Phys 2009, 47(6), 439-40.

Recently, many aluminate materials have been extensively studied as phosphors for the next generation of display and lighting devices. Synthesis of aluminate oxide phosphors has been achieved by a variety of routes: solid-state reactions, sol-gel techniques, microwave processing, hydrothermal synthesis and combustion synthesis. Successfully employed low temperature combustion method for the preparation of BaAl₂O₄:Cr³⁺. Powder X-ray diffraction analysis was used to characterize the as-prepared combustion products, while the optical properties were studied using photoluminescence. The morphological aspect of the resulting powders was examined by scanning electronic microscopy, which showed crystallites with irregular morphology in the form of plates. PL excitation spectrum revealed two broad intense bands located at 421 nm and 552 nm due to Cr³⁺- ions, while emission spectrum showed peaks due to Cr³⁺ ions at 705 nm. EPR spectrum of undoped BaAl₂O₄ showed signals attributable to unintentional Fe³⁺ impurity ions, while EPR spectrum of BaAl₂O₄:C^r3+ contained an additional signal around 3450 G. corresponding to g @ 1.98, typical of Cr³⁺ions.

019418   Singh T D;Singh S D (Physics Dep, Manipur University, Canchipur, Imphal-795 003, Email: dorendrajit @yahoo.co. in) : Kinetic parameters of thermoluminescence glow curves of g-irradiated green calcite. Indian J pure appl Phys 2009, 47(6), 409-12.

The thermoluminescence (TL) glow curves of green calcite irradiated with different doses (1116, 558, 278, 186 and 93 Gy) of g-rays have been studied. The experimental glow curve shows the presence of three peaks with peak temperatures at 413, 503 and 603K. The activation energy and order of kinetics are determined using the computerized glow curve deconvolution (CGCD). Most of the glow curves obey non-first order kinetics.

019417   Singh S Nm (Luminescence Dating Lab, Manipur University, Imphal-795 003, Email: nabadwipsingh@yahoo.com) : Optically stimulated luminescence dating of artifacts excavated from Kangla, Manipur, India. Indian J pure appl Phys 2009, 47(6), 450-2.

Kangla, located at the heart of Imphal city, is almost intersected by 24°N latitude, 94°E longitude, 2619 feet above the mean sea level. An excavation in 2006 at the site by the State Archaeology Department has yielded potteries and bricks at different levels-1.09, 0.72 and 1.64 meter. Using coarse grain of quartz excavated from these artifacts, three samples have been dated using Single Aliquot Regenerative dose (SAR) protocol. A standard commercial Riso (Denmark) TL/OSL reader (model TL DA-15A) has been used for data acquisition. The optically stimulated luminescence (OSL) ages of the samples are in the range 1450-1500 A.D.

019416   Singh K B;Ahmed A B;Gartia R K (Physics Dep, Manipur University, Imphal, Email: rkgartia@yahoo.co.in) : Trap spectroscopy of microcline in the temperature range 77-600 K. Indian J pure appl Phys 2009, 47(6), 406-8.

Trap spectroscopy of microcline (KalSi₃O₈) has been determined by deconvoluting two monochromatic (435 and 285 nm) glow curves. Unlike most studies performed in the range LNT to RT and RT to 400°C separately, in this work thermal scan of the trapping levels has been done right from LNT (77 K) to 600 K. As many as 15 trapping levels could be identified. The most remarkable finding of this analysis is that in microcline, practically all the glow peaks follow second order kinetics, a point that will be discussed critically. For 77K to RT, the frequency factor (s) lies in the range 10⁵ <156> s<156>10⁸ while in the range RT and <175>300°C, it lies in the range 10⁷<156> s<156>10¹². E ~ T_m plot both for UV and blue emission fit to similar equations; E_blue=0.12 exp (0.0045 T_m) .(1) EUV=0.11 exp (0.0049 T_m) .(2) The lifetime (t) of electrons trapped in the trap of depth ∉ 1.5 eV (300°C glow peak) is more than 10⁷ years justifying the use of feldspar in long range dating.

019415   Singh H J;Srivastava P (Chemistry Dep, DDU Gorakhpur University, Gorakhpur-273 009, Email: hari_singh81@hotmail.com) : Computational studies on the structure and vibrational spectra of 2-hydroxy-5-methyl-3-nitropyridine. Indian J pure appl Phys 2009, 47(8), 557-62.

The molecular structure and vibrational spectra of 2-hydroxy-5-methyl-3-nitropyridine have been investigated by Hartree-Fock and Density Functional Theory (DFT) using standard B3LYP functional and 6-311G(d) and 6-311G(3d,2p) basis sets. The results of the calculations are applied to simulate infrared spectra of the title compound which showed good agreement with the experimentally determined data. It has been found that both methods yield consistent data for the geometric parameters but DFT with a basis set of 6-311G(3d,2p) yielded vibrational frequencies much closer to the experimental data. Computed values at DFT(B3LYP)/6-311G(3d,2p) have been analyzed and their characterization was made with the help of Gaussview visualization program utilizing the data obtained from the Gaussian 03 calculation. A few of the discrepancies observed between the experimental and computed data of vibrational frequencies and their assignments have also been discussed.

019414   Sharma M D (Mathematics Dep, Kurukshetra University, Kurukshetra-136 119, Email: mohan_here@rediffmail.com) : Wave propagation in thermoelastic saturated porous medium. J Earth Syst Sci 2008, 117(6), 951-8.

Biot's theory for wave propagation in saturated porous solid is modified to study the propagation of thermoelastic wave in poroelastic medium. Propagation of plane harmonic waves is considered in isotropic poroelastic medium. Relations are derived among the wave-induced temperature in the medium and the displacements of fluid and solid particles. Christoffel equation obtained are modified with the thermal as well as thermoelastic coupling parameters. These equations explain the existence and propagation of four waves in the medium. Three of the waves are attenuating longitudinal waves and one is a non-attenuating transverse wave. Thermal properties of the medium have no effect on the transverse wave. The velocities and attenuation of the longitudinal waves are computed for a numerical model of liquid-saturated sandstone. Their variations with thermal as well as poroelastic parameters are exhibited through numerical examples.

3 illus, 27 ref

019413   Ramasamy V;Ponnusamy V;Sabrai S;Anishia S R; Gomathi S S (Physics Dep, Annamalai University, Annamalai Nagar, Tamilnadu-608 002, Email: srsaranram@rediffmail.com) : Effect of grinding on the crystal structure of recently excavated dolomite. Indian J pure appl Phys 2009, 47(8), 586-91.

Transmission FTIR technique was used to identify the minerals in recently excavated dolomites and study the structural changes of dolomite upon grinding at various grinding periods. KBr pressed disk technique was found to be very useful for a routine characterization of minerals, for examination of structural modification of dolomite and formation of new minerals during grinding. These minerals and processes were also determined using XRD and SEM analysis. The minerals which were formed upon grinding dolomite, were aragonite, anorthite, metakaolinite and periclase.

019412   Ramalingeswara Rao M;Subba Rao B; Poornachandra Rao N;Somaiah K;Murthy K V R (Physics Dep, Vasavi College of Engineering, Hyderabad-500 028, Email: muktevirao@yahoo.co.in) : Thermoluminescence characteristics of MgB₄O₇, MgB₄O₇:Mn and MgB₄O:Cu phosphors. Indian J pure appl Phys 2009, 47(6), 456-8.

The thermoluminescence (TL) characteristics of gamma irradiated MgB₄O₇, MgB₄O₇:Mn and MgB₄O7:Cu phosphors have been studied in the present paper. These phosphors are tried as candidates for PDP panel phosphors. The method of preparation is a standard solid state reaction method. Thermoluminescence studies of gamma irradiated MgB₄O₇ show a TL peak at 225°C with TL intensity around 65 units. The introduction of 1% dopants like Mn and Cu changes the TL pattern i.e TL peak temperature shifts towards higher side at 233°C. The introduction of Cu creates a hump around 290°C.

019411   Patel P K;Kheraj V A;Panchal C J;Desai M S; Vakil P D;Patel K J (Applied Physics Dep, Faculty of Technology and Engineering, M S University of Baroda, Vadodara 390 001, Email: cjpanchal_msu@yahoo.com) : Automated measurements of junction characteristics to evaluate parameters for semiconductor diodes. Indian J pure appl Phys 2009, 47(7), 517-22.

Using National Instrument's LabVIEW (Laboratory Virtual Instrument Engineering Workbench), a graphical programming language, measured the junction characteristics of different diodes in the temperature range 273-373 K. The PCI-6024E Data Acquisition Board and BNC-2120 for the acquisition of the data have been used. LabVIEW's Controls and Functions enable one to control the experiment, measure the parameters, analyze and process the data. Ideality factor h, reverse saturation current I₀, and material constant B have been evaluated using I-V characteristics. The barrier height FB and the band-gap energy E_G, have been measured and compared using both I-V and C-V characteristics. For Schottky diode, the series resistance R_S, and F_B can be calculated using the Norde method. The band-gap energy has been measured using constant current source. Here, we have characterized p-n junction diodes viz. 1N5402, 1N5408, 1N4148, and 6A4. In addition, LabVIEW may be used to characterize other junction diodes like zener diode, LED, varactor diode, Schottky diode, etc.

019410   Pandya A;Shinde S;Jha P K (Institute of Technology, Nirma University, S G Highway, Ahmedabad-382 481, Email: ankur_msub@yahoo.co.in) : Hot electron scattering rates via LO-phonon emission in two-dimensional GaAs_1-xN_x. Indian J pure appl Phys 2009, 47(7), 523-6.

The carrier energy loss rate is studied under low and high electric fields at low temperature with the help of electron-phonon interactions via deformation potential coupling mechanism for two dimensional GaAs_1-xN_x. Observed that at low temperatures, the energy relaxation rate decreases with high electric fields but increases with nitrogen concentration. The electron energy loss rate decreases with nitrogen concentrations at low temperatures. The electron energy loss rate is found to be negative up to certain electric field due to phonon absorption and beyond that, there is phonon emission. The electron drift velocity increases with field but deceases with nitrogen concentration.

019409   Murali Krishna P;Ranjith Kumar B; Sathyanarayana B;Amara K;Satyanarayana N (Chemistry Dep, Kakatiya University, Warangal-506 009, Email: nallani_s@yahoo.com) : Density, viscosity and speed of sound of binary liquid mixtures of sulpholane with aliphatic amines at T =308.15 K. Indian J pure appl Phys 2009, 47(8), 576-81.

Experimental data on density, viscosity and speed of sound have been studied for the binary mixtures of sulpholane with diethylamine, n-propylamine, n-butylamine and tert-butylamine at 308.15 K. Excess molar volume, deviations in viscosity and isentropic compressibility have been computed from this data. The computed quantities have been fitted to the Redlich-Kister equation to derive the binary coefficients and to estimate the standard deviations. All mixtures show negative deviations for excess molar volume, deviations in viscosity and isentropic compressibility. The results have been interpreted on the basis of intermolecular interactions between unlike molecules.

019408   Manish Kumar;Chourasiya G;Kher R K;Bhatt B C; Sunta C M (Radiological Physics and Advisory Div, Bhabha Atomic Research Centre (BARC), Mumbai-400 085, Email: munish_pms@rediffmail.com) : Effect of heating rate on TL glow curves - theoretical and experimental studies. Indian J pure appl Phys 2009, 47(6), 402-5.

In the absence of thermal quenching but at the same radiation dose, the area under the glow curve at different heating rates is conserved only in TL - time plots and is not conserved in TL-temperature plots. Further at a given heating rate, the glow peak height is same in time as well as in temperature plots and the glow peak height increases with the increase of the heating rate. However to conserve area in TL - temperature plots, the TL intensity when divided by the respective heating rate lead to the decrease of glow peak height in TL/b-temperature plots, which is the artifact of the normalization process. The effect of heating rate on TL glow curves has been investigated theoretically as well as experimentally. The ambiguity prevalent in literature regarding the effect of heating rate on TL glow peak height and area under the glow curves when glow curves are plotted in time or temperature scales has been attempted to resolve. It is suggested that researchers should always present un-normalized as well as normalized TL glow curves if the glow curves (for TL sample exposed to same radiation dose) are recorded at different heating rates.

019407   Manam J;Das S (Applied Physics Dep, Indian School of Mines University, Dhanbad-826 004, Email: jairam_manam@yahoo.co.in) : Thermally stimulated luminescence studies of undoped, Cu and Mn doped BaSO₄ compounds. Indian J pure appl Phys 2009, 47(6), 435-8.

Thermally stimulated luminescence (TSL) of undoped and doped BaSO₄ with activators such as Cu and Mn has been investigated. The polycrystalline samples of undoped and doped BaSO₄ are prepared by melting method. The formation of BaSO₄ compound is confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) studies. Comparison of TL intensity of the most intensive glow peak of Cu doped BaSO₄ compound with that of undoped BaSO₄ shows that addition of Cu impurity in BaSO₄ compound enhances the TL intensity by about 9 times. However, the addition of Mn impurity to undoped BaSO₄ increases the TL intensity by about three times when compared with that of undoped BaSO₄. Among the studied samples namely undoped, Cu and Mn doped BaSO₄; Cu-doped BaSO₄ has been found to be the most sensitive.

019406   Madhusoodanan U;Jose M T;Indira R;Gundu Rao T K (Radiation Safety Div, IGCAR, Kalpakkam-603 102) : Luminescence studies in KMgF₃:Eu,Ag. Indian J pure appl Phys 2009, 47(6), 459-60.

A new sensitive material KMgF₃:Eu,Ag has been developed with double dopants europium (Eu) and silver (Ag) by melting equal molecular proportions of KF and MgF₂ along with dopants (0.2 mol % each) in argon atmosphere. Luminescence studies have been carried out in this material to check its possible use in radiation dosimetry applications. Thermoluminescence (TL) studies in this material show that its TL sensitivity is three times that of the existing tissue equivalent material LiF:Mg,Ti (TLD-100), while KMgF₃ doped with Eu alone and Ag alone shows sensitivities equal to that of TLD-100. KMgF₃:Eu,Ag shows a major TL peak around 240°C unlike TLD-100 which has a complicated glow curve shape. The TL emission spectra of gamma irradiated material show characteristic emission of Eu²⁺. Compared to KMgF₃:Eu, the emission intensity of Eu has been found more in KMgF₃:Eu,Ag. Photoluminescence studies show that there is no conversion of Eu²⁺to Eu³⁺ on gamma irradiation. Electron spin resonance (ESR) studies have been carried out in this material to check if there is any valance conversion of Eu and Ag. Both the irradiated as well as unirradiated materials show signal for Eu²⁺ ion and did not show any signal for Ag²⁺ ion. Hence, in the presence of Ag⁺ more Eu²⁺ is entering into the crystal lattice which enhances the luminescence efficiency.

019405   Kapoor K;Dass N (Physics Dep, College of Engineering Roorkee, Vardhamanp Puram, Roorkee-247 667, Email: kmlsrk@rediffmail.com) : Temperature dependent study of volume and thermal expansivity of solids based on equation of state. Indian J pure appl Phys 2009, 47(8), 592-6.

Five different approaches have been used to obtain simple relations to study the temperature dependent volume and thermal expansivity of the solids. All the relations are found to be identical. The computation has been done on six geological solids and three metals with the help of these relations. All the relations are quite successful in representing the volume and the thermal expansivity as a function of temperature. However, the relation obtained with the help of Tait EOS (Equation of State) is found to be better.

019404   Kale Y D;Gandhi Y H (Luminescence Research Lab, Applied Physics Dep, Faculty of Technology, The M S University of Baroda, Vadodara) : Effect of temperature of optical stimulation on thermoluminescence peak of synthetic quartz. Indian J pure appl Phys 2009, 47(6), 413-16.

Several researchers have utilized physical treatments such a annealing temperature, annealing duration, ionizing radiation, grain size and optical bleaching as well as temperature of optical stimulation to establish the definite correlation between TL/OSL sensitivity and colour center with a view to suggest most appropriate physical treatment to be given to the specimen. The effect of temperature of optical stimulation (stimulation at room temperature (RT) (25°C) and stimulation at 160°C) on TL sensitivity, stability of TL peak and role of colour center for specimen annealed at 600°C and 1000°C followed by various beta doses has been studied in the present paper. The TL dose response curves were also plotted for each annealed sample after completion of optical stimulation. The present work reports that the 210°C TL peak is predominant for the specimens annealed at 1000°C prior to optical stimulation at room temperature. This peak remains thermally stable at 210°C and grows with dose systematically regardless of temperature of optical stimulation. The TL peak at 375°C is found to be intense, when the optical stimulation was performed at room temperature or elevated temperature of 160°C. The changes in TL glow curve pattern and sensitivity are strongly attributed to the role of E₁' center and Ge enter.

019403   Gupta K M (Applied Mechanics Dep, Matilal Nehru National Institute of Technology (Deemed Univ), Allahabad-221 004, Email: kmgupta@mnnit.ac.in) : Investigation of the elastic behaviour of an orthotropic mitre bend. Int J theor appl mech 2008, 3(1), 65-72.

Analysis to determine stress intensification has been carried out for 'mitre bend' made of composite (orthotropic) material. The analysis considers in-plane and out-of-plane bending under the effects of 'with internal pressure' and 'without internal pressure' loadings. Shear stress effects and the effect of change in mean radius 'r' of the pipe have also been incorporated in the analysis. The analysis is based on the principles of Strain Energy and Least Work. Computations have been done on a computer, using C language. Results are plotted for varying values of geometrical, material and load parameters. It is concluded that in the process piping, the orthotropic mitre bends will be better alternative (as they show a lower SIF) to metallic bends.

6 illus, 4 ref

019402   Gunasekaran S;Anita B (Spectrophysics Research Lab, Pachaiyappa's College, Chennai-600 030, Email: anitabharathan@yahoo.com) : Vibrational spectra and normal coordinate analysis of diethyl carbamazine. Indian J pure appl Phys 2009, 47(8), 563-7.

A normal coordinate analysis has been carried out for diethyl carbamazine using the vibrational frequencies observed in the FTIR and FTRaman spectra. An orthonormal set of symmetry coordinates has been constructed and Wilson's F-G matrix method has been used for normal coordinate analysis. A satisfactory vibrational band assignment has been made for the molecule in terms of normal modes of vibration using FTIR and FTRaman spectroscopy. A reasonable set of potential constants evaluated for the molecule is found to be in good agreement with the previous studies, thereby confirming the vibrational assignments. Further, to check whether the chosen set of vibrational frequencies contributes maximum to the potential energy associated with the normal coordinates of the molecule, potential energy distribution has been calculated.

019401   Gartia R K;Lovedy L;Ranita U (Physics Dep, Manipur University, Imphal-795 003, Email: rkgartia@yahoo.co.in) : Analysis of glow curves of quartz and transluminescence dating. Indian J pure appl Phys 2009, 47(6), 417-19.

Computerised Glow Curve Deconvolution (CGCD) of glow curves of (N, N+10 and N+15 Gy) sedimentary quartz has been studied. Equivalent dose (ED) of the sample has been evaluated using the well-known additive dose method by using the individual glow peaks obtained by deconvolution. For unheated sediments, ED can be evaluated either using 312°C peak or 276°C peak. The high temperature peaks, located by us around 420, 458, 488 and 540°C normally not considered for dating may also be used in case of heated sediments/potteries/bricks. Unlike the random values of trap-depth reported in some recent paper, our CGCD results clearly show a linear relation between E~kT_m plot, yielding a physically realistic Urbach's co-efficient i.e. 27 for quartz.

019400   ElBatal F H (Glass Research Dep, National Research Center, Dokki, Cairo, Egypt, Email: fh_elbatal@yahoo.co.uk) : Gamma ray interaction with lithium borate glasses containing WO₃. Indian J pure appl Phys 2009, 47(7), 471-80.

Glasses from the system of undoped lithium diborate and WO₃-doped were synthesized by the usual melting and annealing techniques. UV-visible absorption spectra of the prepared sample were measured before and after successive gamma irradiation. Undoped glass reveals strong UV absorption spectrum which is related to the presence of unavoidable trace iron impurity. The presence of tungsten ions in this glass system is observed to impart no colour or marked changes in the absorption spectrum of the host glass suggesting the presence of tungsten ions mostly as W⁶⁺ species. Gamma irradiation produces extended induced bands in the UV-visible regions in the undoped and WO₃-doped glasses. These induced bands are related to the presence of intrinsic defects already present in the host lithium diborate glass and extrinsic defects due to the presence of both trace iron impurity and tungsten ions. Infrared absorption spectra reveal specific vibrational bands due to characteristic borate network beside modifier lithium ions (Li⁺) and tungsten groups. Raman spectra confirm the IR results regarding the presence of tungsten ions mainly as WO₆ groups due to the oxidizing nature of the host glass. Tungsten ions are seen to cause shielding or retardation of the growth of the induced bands by gamma irradiation.

019399   Dogan A;Havvatoglu Y (Faculty of Science and Arts, Physics Dep, Kahramanmaras Sutcuimam University, 46100, K Maras, Turkey, Email: yhavvat@ksu.edu.tr) : Application of rigorous infinitesimal deformation approach to martensitic transformation observed in some Fe-Ni-C alloys. Indian J pure appl Phys 2009, 47(7), 501-5.

Rigorous infinitesimal deformation approach has been used to predict the phenomenological crystallographic parameters such as amount of lattice invariant shear, magnitude of total shape deformation, orientations of habit planes, etc. associated with martensitic phase transformation fcc to bct observed in the alloy Fe-22Ni-0.8C and Fe-29.37Ni-0.34C. The values obtained for the crystallographic parameters in the present study and those from the infinitesimal deformation (ID) approach and experiments have been compared with one another.

019398   Dhabekar B;Alagu Raja E;Gundu Rao T K;Kher R K;Bhatt B C (Radiological Physics and Advisory Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: gundu@iitb.ac.in ) : Thermoluminescence, optically stimulated luminescence and ESR studies on LiAl₅O₈:Tb. Indian J pure appl Phys 2009, 47(6), 426-8.

The LiAl₅O₈:Tb phosphor has been prepared by solution combustion synthesis. LiAl₅O₈:Tb shows two TL peaks at 160 and 330°C, respectively. Continuous Wave OSL (CW-OSL) of LiAl₅O₈:Tb phosphor is recorded. ESR studies have been carried out to identify defect centres responsible for TL peaks observed in LiAl₅O₈:Tb. Room temperature ESR spectra of irradiated LiAl₅O₈:Tb phosphor exhibit two distinct centres. The first ESR line is assigned to a V-centre. The second ESR line is assigned to F⁺ centre. Both the ESR lines appear to correlate with the 160°C TL peak of LiAl₅O₈:Tb phosphor.

019397   Deshmukh A D;Dhoble S J;Kumar A;Peshwe D R; Godbole S V;Bhide M K (Metallurgical and Materials Engineering Dep, VNIT, Nagpur-440 011, Email: sjdhoble@rediffmail.com) : Upconversion luminescence in Eu<. Indian J pure appl Phys 2009, 47(6), 444-6.

The synthesis and optical properties of Eu³⁺ in SrAl₁₂O₁₉ nanophosphor have been studied. All the phosphors were prepared by combustion synthesis and characterized by XRD, EDS, TGA, DTA, particle size analyzer and photoluminescence measurements are carried out. The XRD characterization shows the formation of hexagonal crystalline SrAl₁₂O₁₉ matched with the JCPDS file no. 00-026-0976. SEM and EDS show the formation of nanophosphor and the presence of aluminium, strontium, europium and oxygen. Luminescent characterization shows the emission at 580 nm (yellow) in the visible region by the 858 nm infrared excitation. These results indicate that the Eu doped material is a promising yellow colour fluorescence powder used in colour display or yellow-LED light device using LASER diode as an excitation source.

019396   Deben Singh M;Rangeela Devi Y;Singh S D (Physics Dep, Manipur University, Canchipur, Imphal-795 003, Email: dorendrajit@yahoo.co.in) : Effect of thermal annealing on the thermoluminescence glow curve of X-irradiated BaSO₄Pr. Indian J pure appl Phys 2009, 47(6), 432-4.

Barium sulphate doped with Pr (0.27 mol%) has been synthesized by chemical methods. Thermoluminescence (TL) glow curves of BaSO₄:Pr sample annealed at different temperatures 620, 670, 720, 770 and 820 K, respectively have been recorded after irradiation with X-rays. The observed TL glow curves show a prominent peak at Tm (=436-440) K and two daughter peaks at temperatures (388-399) and (469-477) K, respectively. The dose response curves of the sample annealed at 770 K for 1 h after Tc=450 K is also recorded. Trapping parameters of observed glow curves can be calculated by conventional techniques.

019395   Chougaonkar M P;Gundu Rao T K (Radiation Physics & Advisory Div, BARC, Trombay, Mumbai-400 085, Email: mpckar@hotmail.com) : Confirmation studies of correlation between TL and ESR of natural calcium fluoride. Indian J pure appl Phys 2009, 47(6), 429-31.

Thermoluminescence (TL) and electron spin resonance (ESR) studies were carried out on natural calcium fluoride (Chougaonkar M P & Gundu Rao T K, Proc NCLA-2005, 2005). It was speculated from the studies that the first two TL peaks appearing approximately at 115 and 200°C may be related to two distinct O₂^-(I) and O₂^-(II) radicals, respectively. To assess the validity of the correlation between two ESR centres and the TL peaks, CaF₂ without oxygen impurities were obtained by growing single crystals of natural CaF₂ in oxygen free atmosphere. The oxygen contents in the host material were also removed using PbF₂ as scavenger during the growth. ESR spectrum and TL glow curves were then recorded to study the effect of removal of oxygen from the lattice. The studies indicate that the addition of PbF₂ leads to the removal of precursors of O₂^- radicals as well as CaO present in the lattice and yields clear transparent crystals. It has also been observed that the glow peaks appearing at 115 and 200°C were drastically reduced indicating the near absence of centres responsible for the TL peaks. ESR studies shows the absence radicals O₂^- I as well as O₂^- II, thus confirming that these centres are responsible for the TL peaks.

019394   Chen Y;Wang Z;Zheng J;Zhao X;Li Y (National Key Lab for Electronic Measurement Technology, North University of China, Taiyuan, China, Email: chenyouxing@nuc.edu.cn) : Analysis of sound ray theory and FEM for ultrasonic propagation in a finite rod. Indian J pure appl Phys 2009, 47(8), 572-5.

The presence of echo presented with ultrasonic propagation in a finite metal rod, the sound ray theory is used to analyse the wave mode conversion of ultrasonic propagation in a finite rod and the impact on echo by it, and the conclusion is drawn that the intervals of the echoes are decided by the rod's diameter and wave velocity. The process of ultrasonic propagation through a rod and the final ultrasonic echoes are analyzed by the FEM. In the practical application, based on the results of the FEM simulation for ultrasonic propagation in rods and the selectivity of the material and dimension, the characteristic echo and following echoes are identified at time domain, aiming to extract characteristic echo from the ultrasonic signal.

019393   Celikel O;Eren San S (NO, Tubitak Ume Optics Laboratory, Fiber Optic Metrology Divi, O Box: 54 41470 Gebze-Kocaeli/Turkey, Email: oguz.celikel@ume.tubitak.gov.tr ) : Construction of all digital closed-loop interferometric fiber optic gyroscope with erbium doped fiber amplifier. Indian J pure appl Phys 2009, 47(7), 491-500.

Describes the design details and the characterization of an all digital closed-loop (ADCL) Interferometric Fiber Optic Gyroscope (IFOG) Prototype with sine wave biasing modulation and an erbium doped fibre amplifier (EDFA) pumped by DFB laser emitting at 1549.0 nm as a broadband source. The output of demodulation circuit in the prototype, proportional to the applied rotation rate, was sampled by AD7714YN analog to digital converter (ADC) and operated in 16 bit resolution. Error voltage, generated by microcomputer-controlled LTC 1667CG, 14 bit digital to analog converter (DAC), was sent to the phase modulator through a linear summing circuit, to make Sagnac Phase Shift zero, depending on the rotation direction. The averaged sensitivity of the ADCL-IFOG prototype in unit of error voltage applied to the phase modulator was calculated as 129.21 mV/(°/h) which equals to a scale factor of 7.739 (°/h)/(mV) with a standard deviation of 0.71% for a range of 1-15270 (°/h) rotation rate, corresponding to a range of Sagnac Phase Shifts varying from 0.00115 (°) to 17.57448 (°).The maximum peak to peak noise and the bias stability of the prototype were determined as 3.88 (°/h) and 1.38 (°/h) at 23.0°C, respectively.

019392   Bousnane Z;Benslama M (Physics Dep, Faculty of Science, University of Batna, 05000 Algeria, Email: bousnan@yahoo.fr) : Forced oscillator model for entropic potential in the context of superconductivity. Indian J pure appl Phys 2009, 47(7), 527-9.

The wave function chosen to establish the superconductivity seems to behave as an order parameter at T=T_c. Hereafter, the research of the cooled and cooling depth penetration allows us to obtain the differential equation governing the entropic potential. As similar to the law of the forced macroscopic oscillator, the plurality of the derivative extremums concerning the entropic potential with regard to the quadratic product of the energy, will lead to the matrix nature of the entropy after the centesimal zero. Such differential equation implies that the reduced entropy components will appear as eigen frequencies of the entropic potential. The macroscopic oscillator concept is introduced to express that the distance between the energy levels, will be decomposed univocally on an extremal length scale and multi locally as an inner length scale.

019391   Biolek D;Biolkova V;Kolka Z (EE & Radioelectronics Dep, UD & BUT, Brno, Email: dalibor.biolek@unob.cz) : Current-mode biquad employing single CDTA. Indian J pure appl Phys 2009, 47(7), 535-7.

A novel current-mode (CM) second-order filter, employing one current-differencing transconductance amplifier (CDTA), two grounded capacitors and one virtually grounded resistor. The filter provides two current outputs of lowpass (LP) and bandpass (BP) types for driving independent loads and one high pass (HP) current output, flowing through one of working capacitors. The results of the PSpice simulation, which utilizes the CDTA model on the level of CMOS transistor structure, are enclosed.

019390   Aziz M S;El-Mallah H M (Physics Dep, Faculty of Science, Mansoura University, Damitta, Egypt, , Email: azizm2000@Yahoo.com ) : Electrical and optical properties of azo dye. Indian J pure appl Phys 2009, 47(7), 530-4.

The electrical and optical properties of azo dye (1-phenylazo-2-naphthol) have been investigated. It has been found that the ac conductivity σ_ac(ω) depends on the temperature and frequency. The ac conductivity as a function of frequency has been described by a power law with the frequency exponent s. The obtained values of s > 1 increase with increasing temperature up to T <373 K and then slightly decrease. The results obtained have been described by the nearly constant loss (NCL) behaviour. The dielectric constant σ' and dielectric loss σ' depend on the temperature below elastic temperature T_e and frequency F > 30 kHz and is nearly constant beyond. Both frequency and temperature dependence of the dielectric constant e' and dielectric loss σ' have been attributed to interfacial and orientational polarization, respectively. The optical constants such as refractive index n, the dispersion energy E_d, the oscillation energy E_o, the room temperature optical dielectric constant σ_L, the high frequency dielectric constant at infinite wavelength σ_∞ and the ratio of carrier concentration to the effective mass N/m* have been determined using optical spectra. The spectra of refractive index n, exhibit two peaks and two shoulders at energies 1.455, 2.313, 2.731 and 2.385 eV, respectively.

019389   Arshad Choudhry M;Zafar Javed M (Physics Dep, The Islamia University of Bahawalpur, Pakistan, Email: drmarshadch@yahoo.com) : Screw twinning in monoclinic zirconia. Indian J pure appl Phys 2009, 47(7), 506-10.

A geometrical approach based on the criteria of minimum shuffling after the simple shear and least distortion in bonding is used to find out the acceptable twin boundary structures for (100) and (001) twins in monoclinic zirconia. Possible twin boundary structure for (100) and (001) twins are suggested. The proposed structure for twinning on (100) is within an orientation which can be described as a rotation of π about η1 plus translation of (1/2)c or reflection in K₁ plus a (1/2)b glide. The proposed structure for (001) twin is in an orientation which can be described as rotation of π about ?1 plus translation of (1/2)a or reflection in K₁ plus a (1/2)b glide. These orientation relations are not those which are classically defined for deformation twinning. This may be termed as screw orientation relation.

019388   Alagu Raja E;Dhabekar B;Menon S;More S P; Gundu Rao T K;Kher R K (Radiological Physics and Advisory Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: e_alaguraja@yahoo.com) : Role of defect centres in thermoluminescence mechanism of Tb<. Indian J pure appl Phys 2009, 47(6), 420-5.

Magnesium aluminate (MgAl₂O₄) doped with terbium was prepared by combustion synthesis. Defect centres of MgAl₂O₄:Tb are studied by correlating various techniques such as Electron Spin Resonance (ESR), Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL). TL studies on MgAl₂O₄:Tb³⁺ show two TL peaks at 120 and 340°C. MgAl₂O₄:Tb³⁺ exhibits OSL when stimulated with 470 nm blue light. ESR study shows two defect centres with g = 2.011 and g = 2.0052 which are assigned to V- centre and F⁺ centre, respectively. Step annealing ESR technique study suggests that V-centre is correlated to 120°C TL peak whereas F^{+ centre is correlated with both the 120 and 340°C TL peaks. A TL mechanism is proposed. ESR-OSL correlation studies are carried out. The results of ESR-OSL correlation study along with TL bleaching study support the proposed TL mechanism of 120°C TL peak.}

018392   Yadav T P;Yadav S L;Lalita Kumari (NO, , At - Navtol, P.O. - Dhanauja, Via - Phulparas, Dist. - Madhubani, Bihar) : Electromagnetic and gravitational fields of a charged tachyon. Acta Cienc Indica-Phys 2008, 34(4), 679-83.

It is of interest to obtain the gravitational as well as the electromagnetic fields of a charged tachyon. An axially symmetric axact solution of the Einstein-Maxwell equations has been obtained and is interpreted to give the gravitational and electromagnetic fields of a charged tachyon. Switching off the charge parameter yields the solution for the uncharged tachyon which is in agreement with that obtained by Vaidya. It is clear from equations (1.22-1.23) that the null surfaces for the charged tachyon are different from that of the uncharged tachyon.

14 ref

018391   Yadav T P;Yadav S L;Lalita Kumari (NO, , At - Navtol, P.O. - Dhanauja, Via - Phulparas, Dist.- Madhubani, Bihar) : Electromagnetic and gravitational fields of a radiating dyon. Acta Cienc Indica-Phys 2008, 34(4), 641-6.

14 ref

018390   Yadav T P;Yadav S L;Lalita Kumari (NO, , Navtol, P.O.-Dhanauja, Via-Phulparas, Dist.-Madhubani, Bihar) : Quantum theory in external gravitational field. Acta Cienc Indica-Phys 2008, 34(4), 625-32.

Consider the analogies between quantum theory in an external electro-magnetic field and quantum theory in a gravitational field. Discussed only three important features : (1) The formal correspondence between pair creation in an electric field and pair creation in cosmology. (2) A comparison between gauge invariance in electromaganetism and coordinate invariance in general relativity. (3) The thermal effects which arise due to quantization in singular gauges.

6 ref

018389   Yadav M K;Rai A N (NO, , Bakaur, Distt. Supaul, Bihar) : Analytical study of dynamo transformation of the collisional R-T in a weakly ionized plasma. Acta Cienc Indica-Phys 2008, 34(4), 615-18.

2 illus, 14 ref

018388   Stupka A A (NO, Dnipropetrovsk National Univ, Quantum Chromoplasma Laboratory, Naukova Str., 13, 49050, Dnipropetrovsk, Ukraine, Email: antonstupka@mail.ru) : Gravitation field dynamics in jeans theory. J Astrophys Astr 2008, 29(3-4), 379-86.

Closed system of time equations for nonrelativistic gravitation field and hydrodynamic medium was obtained by taking into account binary correlations of the field, which is the generalization of Jeans theory. Distribution function of the system was built on the basis of the Bogolyubov reduced description method. Calculations were carried out up to the first order of a perturbation theory in interaction. Adiabatic and enthropic types of perturbations were corrected and two new types of perturbations were found.

9 ref

018387   Srivastava S;Kalyan Singh;Srivastava A R (Electronics Dep, Dr. Ram Manohar Lohiya Avadh Univ, Faizabad-224 001) : Neural pattern classifire with error correction (by comparing two errors) in back propagation. Acta Cienc Indica-Phys 2008, 34(4), 599-610.

Neural networks are used to solve complex problem viz., speech and image recognition, pattern recognition (Pattern classification), computer vision etc. Pattern classification by Neural Network using Back Propagation algorithm with error correction (by comparing two errors) for an intelligent gas sensor application is presented. The classifier is trained using published data of thick film tin oxide sensor array. Its superior classification and learning performance is demonstrated for discrimination of alcohols and alcoholic beverages. The new model proposed in this article give better classification efficiency.

5 illus, 17 ref

018386   Srivastava S;Kalyan Singh;Srivastava A R (Electronics Dep, Dr. Ram Manohar Lohiya Avadh Univ, Faizabad-224 001) : Fast training using back propagation algorithm with dependency of previous error in ANN. Acta Cienc Indica-Phys 2008, 34(4), 561-71.

There are various ways through which a Neural Network can be trained using different learning algorithms. Neural Network training by taking effect of previous errors in a more effective way within present error for modification of Back Propagation algorithm parameters (Threshold/ Weight) is presented in order to get minimum error faster using published data of thick film tin oxide sensor array. The new model proposed in this article give steep and monotone learning curve.

5 illus, 11 ref

018385   Somov B V (NO, Astronomical Institute and Faculty of Physics, Moscow State Univ, Moscow 119992, Russian Federation, Email: somov@sai.msu.ru) : Magnetic reconnection and topological trigger in physics of large solar flares. Asian J Phys 2008, 17(3-4), 445-78.

Solar flares are accessible to a broad variety of observational methods to see and investigate the magnetic reconnection phenomenon in high-temperature strongly-magnetized plasma of the solar corona. An analysis of the topological peculiarities of magnetic field in active regions shows that the topological trigger effect is necessary to allow for in order to construct models for large eruptive flares. The topological trigger is not a resistive instability which leads to a change of the topology of the field configuration from pre- to post reconnection state. On the contrary, the topological trigger is a quick change of the global topology, which dictates the fast reconnection of collisional or collisionless nature. The current state of the art and development potential of the theory of collisionless reconnection in the strong magnetic fields related to large flares are briefly reviewed. Particle acceleration is considered in collapsing magnetic traps created by reconnection. In order to explain the formation of coronal X-ray sources, the Fermi acceleration and betatron mechanism are simultaneously taken into account analytically in a collisionless approximation. Finally, the emphasis is on urgent unsolved problems of solar flare physics.

20 illus, 2 tables, 70 ref

018384   Siya Sharan;Mishra L K (NO, , C/o Sri Ram Naresh Prasad Sharma, At. - Deodharpur, P.O. - Tekari, Dist. - Gaya-824 236) : Evaluation of temperature dependent pressure at constant volume volume of normal liquid <. Acta Cienc Indica-Phys 2008, 34(4), 633-9.

Using almost localised Fermion model, we have evaluated the temperature dependent pressure at constant volume. Using two parameters as (m* = m) and (m* = m/q), we have evaluated [P-P(0)] as a function of T with three values of p(0)[0, 15 & 30 bar]. Theoretical results are in good argument with those of the experimental data.

2 tables, 17 ref

018383   Sinha S K;Singh N K (Physics Dep, L.N. Mithila Univ, Darbhanga-846 004) : Wide-band half U-solt patch antenna. Acta Cienc Indica-Phys 2008, 34(4), 619-24.

Wide-Band Half U-Slot Patch Antenna, a single layer single patch antenna on a relatively thick substrate (~ 0.08 λ_o) has been studied. It is a Wide -Band miniature antenna with an impedance Band - Width in a range of 20% - 30%, which is about an order of magnitude larger than that of the regular patch antenna. By simulation the different radiation properties of this antenna has been studied. The results are in agreement with the experimental results available in literature.

4 illus, 2 tables, 9 ref

018382   Sharan S;Mishra L K (NO, , C/o Sri Ram Naresh Prasad Sharma, At. - Deodharpur, P.O. - Tekari, Dist. - Gaya - 824 236) : Evaluation of temperature dependence spin susceptibility of normal <. Acta Cienc Indica-Phys 2008, 34(4), 685-92.

Using almost localised fermion model of K. Seller et. al., evaluated the value of spin susceptibilities (XI X₀) as a function of T for liquid ³He for 7 below 2.5 K, for fixed values of P(0) = 0, 15 and 30 bar. The theoretically evaluated results are in good agreement with the experimental data.

1 table, 15 ref

018381   Sharan S;Mishra L K (NO, , C/o/ Sri Ram Naresh Prasad Sharma, At. : Deodharpur, P.O. Tekari, Dist.-Gaya-824 236) : Evaluation of temperature dependent C_V of normal <. Acta Cienc Indica-Phys 2008, 34(4), 663-9.

Using model of almost localized fermions by K. Seiler et. al., evaluated the temperature dependent C_v of normal liquid ³He. The theoretical evaluated result are in good argument with experimental data of Greywall.

1 table, 26 ref

018380   Sharan S;Mishra L K (NO, , C/o Sri Ram Naresh Prasad Sharma, At. - Deodharpur, P.O. - Tekari, Dist. - Gaya-824 236) : Evaluation of temperature dependent (C_V/RT) and entropy (S/R) of normal <. Acta Cienc Indica-Phys 2008, 34(4), 647-55.

Using almost localised fermion, we have evaluated the temperature dependent (C_v/RT) and (S/R) of normal liquid. The our theoretically evaluated results are in good agreement with the. experimental data.

3 tables, 15 ref

018379   Niranjan K;Sreekanth V;Madhavan B L;Anjana Devi T;Spandana B (Physics Dep, Andhra Univ, Visakhapatnam-530 003, Email: niranjankandula@hotmail.com) : Temporal characteristics of aerosol physical properties at Visakhapatnam on the east coast of India during ICARB-signatures of transport onto Bay of Bengal. J Earth Syst Sci 2008, 117(S1), 421-7.

Realizing the importance of aerosol physical properties at the adjoining continental and coastal locations in the airmass pathways onto the oceanic region, extensive measurements of aerosol physical properties were made at Visakhapatnam (17.7°N, 83.3°E), an eastern coastal location in peninsular India during the ICARB period. The temporal variations of aerosol optical depth, near surface aerosol mass size distributions and BC mass concentrations show significantly higher aerosol optical depth and near surface mass concentrations during the first and last weeks of April 2007. The mean BC mass fraction in the fine mode aerosol was around 11%. The aerosol back scatter profiles derived from Micro Pulse Lidar indicate a clear airmass subsidence on the days with higher aerosol optical depths and near surface mass fraction. A comparison of the temporal variation of the aerosol properties at Visakhapatnam with the MODIS derived aerosol optical depth along the cruise locations indicates a resemblance in the temporal variation suggesting that the aerosol transport from the eastern coastal regions of peninsular India could significantly affect the aerosol optical properties at the near coastal oceanic regions and that the affect significantly reduced at the farther regions.

9 illus, 15 ref