004089   Chakraborty B R;Diva K;Kabiraj D;Avasthi D K (NO, National Physical Laboratory, New Delhi-110 012) : Characterisation of swift heavy ion-induced mixing using secondary ion mass spectrometry. Def Sci J 2009, 59(4), 356-62.

Swift heavy ions of Au at 120 MeV are irradiated at the interface of Si/Me/Si (Me=V,Fe,Co) and the behaviour of mixing examined wrt to different ion doses. The fluences were varied from 1x10¹³ ions/cm² to 1x10¹⁴ ions/cm² on the multilayers of Si/Me/Se (Me=V,Fe,Co) and the interface of Si/Me(Me=V,Fe,Co) were characterised using Rutherford backscattering spectroscopy(RBS) and secondary ion mass spectrometry (SIMS). The atomic mixing width was found to be increasing monotonically with ion fluence in all the three cases. The mixing rate and efficiency calculations were made and the diffusivity values thus obtained suggested a transient melt phase at the interface according to thermal spike model. In case of Me=Co, it was further probed with XRD and Raman spectroscopy to confirm the formation of cobalt silicides even at room temperature.

7 illus, 1 table, 29 ref

004088   Bhan R K;Saxena R S;Jalwania C R;Lomash S K (NO, Solid State Physics Lab, Delhi-110 054) : Uncooled infrared microbolometer arrays and their characterisation techniques. Def Sci J 2009, 59(6), 580-9.

Reviews the basic principles of these detectors and some of the important works done internationally in this field. Presents some of the research work on titanium microbolometer carried out at Solid State Physics Laboratory, Delhi.

^iia9 illus, 2 tables, 35 ref

003091   Wadia S R (International Center for Theoretical Sciences and Dep of Theoretical P, Tata Institute of Fundamental Research, Homi Bhabha, Mumbai-400 005, Email: wadia@tifr.res.in) : String theory: a framework for quantum gravity and various applications. Curr Sci 2008, 95(9), 1252-67.

In this semi-technical review authour discuss have string theory (and all that goes by that name) as a framework for a quantum theory of gravity. This is a new paradigm in theoretical physics that goes beyond relativistic quantum field theory. We provide concrete evidence for this proposal. It leads to the resolution of the ultra-violet catastrophe of Einstein's theory of general relativity and an explanation of the Bekenstein-Hawking entropy (of a class of black holes) in terms of Boltzmann's formula for entropy in statistical mechanics. We dis-cuss 'the holographic principle' and its precise and consequential formulation in the AdS/CFT correspon-ri dence of Maldacena. One consequence of this correspondence is the ability to do strong coupling calculations in SU(N) gauge theories in terms of semi-classical gravity. In particular, Indicate a connection between dissipative fluid dynamics and the dynamics of black hole horizons. Elementary particle physics and cosmology in the framework of string theory has been discussed and do not cover all aspects of string theory and its applications to diverse areas of physics and mathematics, but follow a few paths in a vast landscape of ideas.

33 ref

003090   Verma A;Khare P K;Srivastava R K (Physics Dep, Bipin Behari P.G. College, Jhansi-284 001) : Electrode effect on electrical conduction in thin film of polyvinyl pyrrolidone. Indian J pure appl Phys 2009, 47(10), 737-44.

Electrical conduction behaviour in ployvinyl pyrrolidone (PVP) has been investigated in both transient and steady state conditions in the temperature range 40-80°C at different dc electric fields from 05 to 100 kV/cm using similar and dissimilar, both types of electrode systems. The nature of transient currents has mainly been attributed to the dipolar nature of PVP in the lower temperature region where slope value n of the Curie Von Schweidler law is found to vary from 0.43 to 0.62 for similar electrode system and from 0.78 to 0.98 for dissimilar electrode system. The low field steady state conduction is found to be ohmic in nature. The high field non-linear nature of conduction currents is found to be strongly temperature dependent and an attempt has been made to explain these curves taking into account various conduction processes. A strong temperature dependence of the conduction current rules out tunnelling as the possible conduction mechanism. The Poole-Frankel and Richardson-Schottky coefficients estimation shows that Richardson-Schottky conduction mechanism is operative in controlling the transport of charges in PVP foil electrets. This result is, further, confirmed using different electrodes systems of Jonscher and Ansari.

003089   Upadhyay T C;Semwal K P (Physics Dep, H N B Garhwal University, Srinagar (Garhwal), Uttarakhand-246 174, Email: trilokphys@yahoo.co.in) : Temperature and electric field dependence of soft mode frequency, dielectric constant and loss tangent in rochelle salt crystal. Indian J pure appl Phys 2009, 47(12), 883-8.

Two-sublattice pseudospin lattice coupled mode model of Chaudhuri et al. [J Phys Soc Japan, 49 (1980) 609.] along with third-and fourth-order phonon anharmonic interaction terms and electric field term, has been considered. By using double-time temperature dependent Green's function method, expressions for shift, width, soft mode frequency, dielectric constant and loss tangent are obtained for rochelle salt crystal. By fitting model values of physical quantities, temperature dependence of soft mode frequency, dielectric constant and loss tangent have been calculated for different fields for rochelle salt. Theoretical results are seen to compare well with the experimental results of Sandy and Jones [Phys Rev, 168 (1968) 481].

003088   Tangsrirat W (Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang (KMITL), Chalongkrung Road, Ladkrabang, Bangkok 10520, Thailand, Email: drworapong@yahoo.com) : Novel minimum-component universal filter and quadrature oscillator with electronic tuning property based on CCCDBAs. Indian J pure appl Phys 2009, 47(11), 815-22.

The novel current-tunable voltage-mode universal biquad filter and sinusoidal quadrature oscillator using only two current-controlled current differencing buffered amplifiers (CCCDBAs) and two capacitors without external passive resistors have been presented. The first proposed filter realizes all the five standard types of the biquadratic functions and provides independent electronic tuning of the natural angular frequency (ω_o) and the bandwidth (BW) through an external bias current of the CCCDBA. No critical component matching conditions are required. The second proposed oscillator generates two sinusoidal output voltages with 90° phase difference. Its oscillation condition and the oscillation frequency (ω_o) are tunable independently through adjusting the bias current of the CCCDBA. Both the proposed circuit configurations have a low component count, attractive active and passive sensitivities and suitability to integrated circuit implementation. PSPICE simulation results that confirm the theoretical prediction, are also given and discussed.

003087   Tandon P;Uttam K N (Saha's Spectroscopy Lab, Physics Dep, University of Allahabad, Allahabad-211 002, Email: pavitraofau@rediffmail.com ) : Estimation of thermodynamical quantities of tin chalcogenides from spectroscopic data. Indian J pure appl Phys 2009, 47(10), 725-9.

Statistical thermodynamics and spectroscopy have been combined to evaluate thermodynamical quantities of tin chalcogenides (SnO, SnS, SnSe and SnTe). Their temperature dependence has been studied in the temperature range 100-2200K. The authenticity of data is established by the comparison of reported values. Discrepancies between calculated values and observed values can mainly be attributed to contributions from excited electronic states.

003086   Sumathi T;Uma Maheswari J (Physics Dep, DDE, Annamalai University, Tamilnadu, Email: tsumathi92@yahoo.com) : Ultrasonic and theoretical studies of some ternary liquid mixtures at various temperatures. Indian J pure appl Phys 2009, 47(11), 782-6.

Various acoustical parameters such as adiabatic compressibility (β), free length (Lf), free volume (V_f), internal pressure (π_i), excess adiabatic compressibility (β^{E), excess free length (L_fE), excess free volume (V_fE), excess internal pressure (π_iE), excess viscosity (ηE) and excess velocity (UE) have been evaluated from density, viscosity and speeds of sound measurements for solvent systems consisting of methyl acetate and toluene with 1-pentanol, 1-hexanol and 1-heptanol at 303.15, 308.15 and 313.15 K. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the ternary mixtures. The ultrasonic speeds calculated according to Nomoto's relation, impedance dependence relation and collision factor theory are compared with those obtained experimentally.}

003085   Singh N;Mishra V;Jain S C;Sreekanth K V; Poddar G C;Kapur P (NO, Central Scientific Instruments Organisation, Sector 30, Chandigarh-160 030) : Enhanced sensitivity refractive index sensor based on segmented fiber with bending. Indian J pure appl Phys 2009, 47(9), 655-7.

Refractive index sensor fabricated by splicing segments of multimode and single mode fibers was investigated for enhanced sensitivity. The investigation revealed that when this sensor is used in bent position its sensitivity is improved by a factor of 5 to 10 depending on its bend curvature. It was found that the sensitivity is enhanced as the curvature is increased.

003084   Singh K D;Rakesh Kumar (Mathematics Dep, (ICDEOL), H P University, Shimla-171 005, Email: kdsinghshimla@gmail.com ) : Combined effects of Hall current and rotation on free convection MHD flow in a porous channel. Indian J pure appl Phys 2009, 47(9), 617-23.

Theoretical analysis of an oscillatory free convective MHD flow of a viscous incompressible and electrically conducting fluid in a vertical porous channel in the presence of Hall current has been carried out. The two insulating porous plates are subjected to a constant injection and suction. A uniform magnetic field is applied in the direction normal to the plates. The entire system rotates about the axis normal to the plates with uniform angular velocity Ω. For small and large rotations, the dependence of the steady and unsteady resultant velocities and their phase differences on various parameters have been discussed in detail. The results show that both steady and unsteady resultant velocities increase rapidly from zero near the stationary plate and then approach to unity in the form of damped oscillations. For large values of rotations and injection/suction at the plates, a phase lag is also observed for both steady and unsteady phase angles.

003083   Singh D;Jaggi N;Singh N (Physics Dep, D S College, Karnal-132 001, Email: ds_kuk@yahoo.com) : Vibrational analysis of 1,8-dichlorooctane. Indian J pure appl Phys 2009, 47(10), 696-702.

Fourier transform infrared (FT-IR) and Raman spectra of the organic compound 1,8-dichlorooctane (1,8-DCO) have been recorded in the range 4000-400cm^-1 and 3500-100 cm^-1, respectively. A detailed vibrational analysis in terms of assignment of observed frequencies of this molecule for its four most probable conformations in liquid state, having all its carbon atoms in the same plane, with symmetries C_2h, C_I, C₂ and C₁ has been done. A systematic set of symmetry coordinates has been constructed for this molecule and normal coordinate calculations are carried out using the computer program MOLVIB. The force-field transferred from already studied lower chain chloro-alkanes is subjected to refinement so as to fit the observed frequencies with that of calculated ones. The potential energy distribution (PED) has been calculated for each mode of vibration of the molecule for the assumed conformations.

003082   Singh B P;Baghel V S;Baghel K S (Physics Dep, Institute of Basic Sciences, Khandari, Agra-282 002, Email: drbps_ibs@yahoo.co.in) : Electronegativity, fractional ionic character and refractive index of binary compounds. Indian J pure appl Phys 2009, 47(11), 793-803.

Analysis is presented for the electronegativity, fractional ionic character and refractive index of binary compounds with monovalent, divalent and trivalent atoms. The values of electronegativity difference by investigating a relationship between fractional ionic character and electronegativities have been determined. More accurate values of ionicity based on the revised energy gap model have been used in the present study to obtain the new results. The values of electronegativity difference are found to be correlated well with the values of refractive index and energy gap in case of I-VII, II-VI and III-V binary compounds.

003081   Sarma R;Saikia D (Thin Film Lab, Physics Dep, J B College, Jorhat, Assam, Email: sarmamax2000@yahoo.com) : Study of tetracene thin film transistors using La₂O₃ as gate insulator. Indian J pure appl Phys 2009, 47(12), 876-9.

Tetracene organic field-effect transistors (OFET) have been fabricated and investigated with La₂O₃ as gate insulator. The fabricated organic thin film transistors exhibit p-type conductivity with field effect mobility 1.04'10^-4 cm²/V.s, ON-OFF ratio 3.465, sub-threshold swing 17.8 mV/decade and hole concentration 1.25'10¹⁹ cm^-3. The SEM and XRD analysis on the semiconductor film were have also been reported.

003080   Sahoo S;Das S (Physics Dep, National Institute of Technology, Durgapur-713 209, Email: sukadevsahoo@yahoo.com) : Fractional quantum Hall effect in graphene. Indian J pure appl Phys 2009, 47(9), 658-62.

Electrons in most of the conductors can be described by non-relativistic quantum mechanics but the electrons in graphene behave as massless relativistic particles, called Dirac fermions, though their speed is given by the Fermi velocity. The relativistic nature of the energy dispersion relation of electrons in graphene modifies the inter electron interactions. This results in the observation of a number of peculiar properties e.g. anomalous quantum Hall effect. We study the fractional quantum Hall effect (FQHE) in graphene. The quantized Hall conductivity in graphene in FQHE is shown to be: σ_xy = ± 2n+1/2m(2n+1)+1 2e²/h, where n = 0, 1, 2, 3 . This fascinating result shows that the FQHE in graphene has a sequence of states which is different from the sequence found in the 2D electron gas.

003079   Rastogi V K;Singhal S;Pavan Kumar A;Ramana Rao G;Palafox M A;Kostova I (Physics Dep, C C S University, Meerut-250 004, Email: v_krastogi@rediffmail.com) : Vibrational spectra, normal coordinate analysis and thermodynamics of 2-chloro-5-nitrobenzonitrile. Indian J pure appl Phys 2009, 47(12), 844-51.

The laser Raman (0-3500 cm^{-1) and FTIR (200-4000 cm-1) spectra (Nujol, KBr, liquid and vapour) of 2-chloro-5-nitrobenzonitrile have been recorded. A zero-order normal coordinate analysis has been made for the molecule using force constants derived earlier. On the basis of potential energy distributions and eigen vectors unambiguous vibrational assignments have been made for all the fundamentals of the molecule. The ideal gas state thermodynamic functions of the molecule are also computed in the temperature range 200-1500 K by utilizing the observed fundamental frequencies assuming rigid-rotor harmonic oscillator approximation.}

003078   Ramakrishnan T V (Physics Dep, Banaras Hindu Univ, Varanasi-221 005, Email: tvrama2002@yahoo.co.in) : Strongly correlated electrons in solids. Curr Sci 2008, 95(9), 1284-1309.

In this review, phenomena and ideas connected with strongly interacting electrons in condensed matter systems will be outlined. A simple picture which regards electrons as basically a free gas of quantum particles is the basis of our understanding of all electronic behaviour of metals and insulators. In the last few decades, families of systems have been explored in which the interaction energy is much larger than the energy of free motion, or kinetic energy. These include transition metal oxides with unfilled d electron shells, rare earth intermetallics with f electrons, etc. Their behaviour is rich and not well understood in terms of existing paradigms. I point out some experimental features common to these, e.g. that they are 'bad' metals with unusually low quantum coherence temperatures. I also briefly give illustrative examples such as cuprates (which are high temperature superconductors), man-ganites (exhibiting colossal magnetoresistance) and heavy fermions (rare earth intermetallics). Some of the ideas, theories and methods available for describing these sysytems are outlined. It is suggested that a new general approach may be needed for this qualitatively different regime of many electron behaviour.

23 illus, 145 ref

003077   Peimbert M (Instituto de astronomia, Universidad Nacional Autonoma de Mexico, Mexico, 04510 DF, Mexico, Email: peimbert@astroscu.unam.mx) : Primordial helium abundance. Curr Sci 2008, 95(9), 1165-76.

Brief review has been presented on the determination of the primordial helium abundance by unit mass, Y_P. I discuss the importance of the primordial helium abundance in: (a) cosmology, (b) testing the standard big bang nucleosynthesis, (c) studying the physical conditions in II II regions, (d) providing the initial conditions for stellar evolution models, and (e) testing the galactic chemical evolution models.

8 illus, 4 tables, 69 ref

003076   Panditrao A M;Rege P P (NO, Cummins College of Engineering for Women, Pune-411 052, Email: anagha.panditrao@gmail.com) : Estimation of spectral response of a consumer grade digital still camera and its application for temperature measurement. Indian J pure appl Phys 2009, 47(10), 703-7.

Consumer grade digital still camera has been used for image acquisition of various heat sources and the spectral response of camera has been obtained. Different sources are used to cover the bandwidth ranging from IR to UV. From the results, it has been observed that the response of the digital camera used to capture source images is adequate to cover visible range (400-700 nm). The images of various visible known heat sources are captured using the mentioned camera. From the captured images, various zones of the source are identified using image-processing algorithms. The actual temperature is measured by placing a miniature k type thermocouple in each zone. The measured temperature values are correlated with the respective colours and features computed from the images. The colour temperature correlation is established by applying various analytical techniques. Calibration of the image-based measurement with contact measurement using an established sensor is performed.

003075   Pandit P;Rakshit B;Sanyal S P (Computational Research Lab, Physics Dep, Barkatullah University, Bhopal-462 026, Email: lataprem29@gmail.com ) : Electronic and elastic properties of alkali-metal sulphides-Li₂S and Na₂S. Indian J pure appl Phys 2009, 47(11), 804-7.

From first-principles, the electronic and elastic properties of alkali-metal sulphides (Li₂S, Na₂S), with emphasis on the plane-wave pseudopotential method and the inclusion of the non-linear core correction for exchange and correlation have been investigated. At ambient condition, these compounds are found to crystallize in cubic anti-fluorite structure. This method is found to describe the properties of these materials rather well. In most of the cases, obtained ground state properties are in good agreement with experimental and theoretical results. From the electronic structure calculations, we found that Li₂S is indirect band gap semiconductor whereas Na₂S is direct band gap semiconductor within local density approximation (LDA).

003074   Pandey S K;Dubey S C (Physics Dep, Rewa Engineering College, Rewa-486 001, Email: skpandeygecrewa@yahoo.co.in) : Characteristic features of large geomagnetic storms observed during solar cycle 23. Indian J Radio Space Phys 2009, 38(6), 305-12.

A set of 90 large geomagnetic storms, associated with disturbance storm time (Dst) (decreases of more than 100 nT) observed during 1997-2007, have been analysed. The analysis included various characteristics features as well as seasonal and solar cycle dependence of these storm events. It has been found that all severe geomagnetic storms are associated with coronal mass ejections (CMEs) during the solar cycle 23. A comparative study of 11 severe geomagnetic storms (Dst ≤ -250 nT) and their associative solar driver have also been discussed.

003073   Nayak A;Goswami K;Ghosh A;Debnath R (NO, Central Glass and Ceramic Research Institute, 196, Raja S C Mullick Road, Kolkata-700 032, Email: debnath@cgcri.res.in) : Luminescence efficiency of Eu<. Indian J pure appl Phys 2009, 47(11), 775-81.

Effect of incorporation of trace (Al⁺³, B⁺³) in the Y₂O₃ lattice on the luminescence efficiency of Y₂O₃:Eu⁺³ red phosphor has been investigated. It is observed that such incorporation causes an enhancement of ⁵D₀→⁷F₂ red luminescence efficiency as well as the associated excitation efficiency of Eu⁺³. It is concluded that there occurs a change in the polarity of the host rather than the site symmetry of Eu⁺³ due to incorporation of the hetero cations. Calculation of the Judd-Ofelt parameters gives similar results. In another study, to observe the effect of reduction of particle size on the luminescence efficiency of the Y₂O₃:Eu^{+3, the change in luminescence efficiency of the phosphor with the reduction particle size and the stability of the different efficiencies with the elapse of time have been investigated. The samples with particle size below 100 nm showed a significant loss in luminescence efficiency and a change in their excitation profile with time. IR studies showed that although the freshly prepared samples were almost free from contaminated water, on ageing in air at room temperature, they absorb the latter. A phenomenon of hydration induced coupling of the excitonic state of Y₂O₃ with one of its F_u modes, has been detected in the case of the aged samples which susequently introduces newer non-radiative channels in the system causing a decrease in the luminescence efficiency of the phosphor. Because of larger surface to volume ratio, the effect is most pronounced in nanocrystalline samples.}

003072   Nautiyal O P;Bhatt S C;Semwal B S (Physics Dep, H N B Garhwal University, Srinagar, Srinagar Garhwal, Uttarakhand, Email: nautiyal_omprakash@yahoo.co.in) : Preparation and characterization of ceramic samples of Ag_1-xK_xNbO₃. Indian J pure appl Phys 2009, 47(10), 719-24.

Ceramic pellets of silver potassium niobate (Ag1_-xK_xNbO₃) system have been prepared by conventional sintering method. The prepared samples are characterized by X-ray diffraction (XRD) and scanning electron micrographs (SEM) techniques. Lattice parameters have been calculated by XRD pattern and grain size has been calculated by SEM. It has been observed that all the prepared samples show orthorhombic structure at room temperature.

003071   Nandan H;Bezares Roder N M;Chandola H C (Centre for Theoretical Studies, Indian Institute of Technology, Kharagpur-721 302) : Screening current and dielectric parameters in dual QCD. Indian J pure appl Phys 2009, 47(11), 808-14.

The screening current mechanism and dual Meissner effect in the QCD vacuum have been studied in view of the action for a dual (magnetic) superconductor derivable from the Zwanziger's two-potential formalism. The flux tube structure emerging as an artifact of screening current in the background of both the monopole and dyon condensation has been investigated. The magneto-statical representation of the flux tube has also been presented with the conditions which are necessary to form a tube. The dielectric parameters of dual QCD vacuum have been calculated and the size of the flux tube resulting from the monopole and dyon condensation is compared.

003070   Mohanta A;Behera D (Physics Dep, National Institute of Technology, Rourkela-769 008, Email: dhrubananda_behera@yahoo.in) : Effect of Ga and Zn doping on coherent transition of YBCO superconductor. Indian J pure appl Phys 2009, 47(9), 676-80.

The simultaneous incorporation of Ga³⁺ and Zn²⁺ to the Cu-site of Yba₂Cu₃O₇-δ has been analyzed for microstructural and electrical properties. Temperature-dependent electrical resistivity, X-ray diffraction and SEM analysis of a set of Yba₂(Cu_0.95Zn_0.05-_xGa_x)₃O_7-y films prepared by solid state reaction technique have been investigated to study the substitutional effects of Ga and Zn at chain and plane site of Cu, respectively. The redistribution of charges in the superconducting system due to oxygen content and the resistance of the weak-links related inhomogeneities give rise to T_c degradation and dual values of exponents in the T_c0 region. The exponent values for fluctuation conductivity in the T_c0 region decrease with increase of substitution concentration. The dual exponent character shows that the intergranular weak links develop more resistance with increasing impurities.

003069   Mathew V;Joseph J;Jacob J;Jacob S;Varughese P A;Abraham K R (NO, St Aloysius' College, Edathua, Alappuzha, Kerala, Email: abrahamke@gmail.com) : Spectral properties of cadmium malonate crystals grown in hydrosilica gel. Indian J pure appl Phys 2009, 47(10), 691-5.

Cadmium malonate crystals have been grown by gel aided solution technique employing sodium metasilicate. X-ray diffractogram of the compound gives well defined peaks. FTIR and FT Raman spectral studies confirm the presence of water molecules and functional groups. Metal-metal bonding is also identified. Using diffuse reflectance spectroscopy (DRS) studies, the band gap of the sample is estimated.

003068   Mallikarjun S L;Madhuri R G;Malipatil S A; Hadalgi P M (PG Studies and Research in Applied Electronics Dep, Gulbarga University, Gulbarga-585 106, Email: mslakshetty@rediffmail.com) : Development of microstrip array antenna for wide band and multiband applications. Indian J Radio Space Phys 2009, 38(5), 289-94.

The design and development of an X-band linearly polarized microstrip array antenna. The array elements are fed by corporate feed network, which improves the impedance bandwidth of the two element rectangular microstrip array antenna (2RMSAA) by 15.38%. By increasing the array elements from two to four and eight, multiband operation can be achieved with improved impedance bandwidth. These multiband array antennas may provide an alternative to large bandwidth planar antennas in applications where large bandwidth is needed for operating at two separate transmit-receiver frequencies. When the two operating frequencies are far apart, a multiband antenna can be used to avoid the use of separate antennas. Experimental results for the array antennas in term of return loss, radiation pattern, -3dB beam width, and gain are presented.

003067   Mallick B;Lakshmanna A;Radhalakshmi V; Umapathy S (Inorganic and Physical Chemistry Dep, Indian Institute of Science, Bangalore-560 012, Email: umapathy@ipc.iisc.ernet.in) : Design and development of stimulated raman spectroscopy apparatus using a femtosecond laser system. Curr Sci 2008, 95(11), 1551-9.

Presents the design and development of a stimulated Raman scattering (SRS) experimental set-up using a femtosecond laser system. The set-up involves the generation of (i) a picosecond (ps) narrow-bandwidth (5-20 cm^-1) Raman pump, and (ii) a femtosecond (fs) broadband continuum Raman probe pulse (800-1050 nm) providing the Stokes field, covering vibrations in the range 300-2500 cm^-1. When the two fields interact with the system simultaneously, gain features are observed on top of the probe beam at frequency corresponding to the characteristic molecular vibration frequency of the system. The ratio of the probe spectrum with and without the Raman pump provides a background-free gain spectrum. We present initial studies on some standard systems, viz. benzene, cyclo-hexane and β-carotene in CCl₄/benzene. These studies indicate that this technique provides a better signal with improved signal-to-noise ratio even for a low acquisition time in comparison with normal Raman spectroscopy.

12 illus, 24 ref

003066   Mahato D N;Prasad R N;Mathur B K (Physics Dep, IIT, Kharagpur-721 301, Email: dn.mahato08@yahoo.com) : Surface morphological, band and lattice structural studies of cellulosic fiber coir under mercerization by ESCA, IR and XRD techniques. Indian J pure appl Phys 2009, 47(9), 643-7.

Electron spectroscopy for chemical analysis (ESCA) studies show the increased binding energy (BE) of C1_s and O1_s on mercerization. The oxygen to carbon ratio increases. The cellulose I lattice structure is preserved, which is reflected in the XRD and IR spectra. These assume significance because these changes reflect in the structure-sensitive physical properties. The change in oxidation state is supported by 2929 cm^-1 band. The band at 1267 cm^-1 gives depolymerization. The IR band at 1433 cm^-1 gives idea of restriction of lattice transformation from cellulose I into cellulose II, which is confirmed by XRD pattern. The fiber undergoes disappearance of crystallinity, depolymerization and oxidation.

003065   Lin C S;Wu J M;Ho C W;Lee C J;Yeh M S (Automatic Control Engineering Dep, Feng Chia University, Taichung, Taiwan) : Automatic inspection system for measurement of lens field curvature by means of computer vision. Indian J pure appl Phys 2009, 47(10), 708-14.

Proposes an automatic inspection system for field curvature in order to replace the present lens measurement device for curvature of field and manual adjusting of screen distance. The system utilizes a screen equipped with automatic driving system and computer vision technique, along with DLP projection and computer software to capture data from image area by scanning, and then obtains the average and threshold values of its pixels. The analysis is based on 8 adjoining points to conduct contractive algorithm between bright spot and dark spot, and automatically measure the figure projected on a screen and provide real-time measuring results. The drawbacks of traditional manual measurement can be completely avoided by this system. When comparing the measured result with that of the optics emulating software, the accuracy and time effect of this automatic inspection measurement for the lens aberration of field curvature are significant.

003064   Lamani A R;Jayanna H S;Parameswara P; Somashekar R (Studies in Physics Dep, Kuvempu University, Shankarghatta-577 451, Email: rs@physics.uni-mysore.ac.in) : Microcrystalline parameters of Cu-Zn ferrites using X-ray line profile analysis. Indian J pure appl Phys 2009, 47(10), 715-8.

Cu-Zn ferrites are synthesized by double sintering ceramic method. X-ray analysis of Cu-Zn ferrite shows the single phase spinel structure. The structural and microstructural parameters have been computed using X-ray diffraction data. Using CheckCell program, the Bragg reflections have been indexed. The estimated microstructural parameters have been correlated with the reported physical parameters. In the present paper, an analytical asymmetric function like exponential distribution function was used to describe the paracrystalline statistics of column length distribution in Cu-Zn ferrites and a good convergence was observed with this function.

003063   Kushwah S S;Bhardwaj N K (Physics Dep, Rishi Galav College, Morena-476 001, Email: sobrank@yahoo.com) : Pressure-volume relationships and bulk modulus for sodium halides. Indian J pure appl Phys 2009, 47(9), 663-6.

Equation of state for solids developed by Kushwah et al. [Physica B, 388 (2007) 20] has been used here to determine the pressure-volume relationships, bulk modulus and its pressure derivatives for NaF, NaCl, NaBr and NaI solids. The results are found to present close agreement with the experimental data. The results for P, K and dK/dP at different compressions have been used to study the relationship between dK/dP and P/K.

003062   Karmakar S;Patowary K;Bhattacharjee S K;Deka B;Chakraborty A (Instrumentation & USIC Dep, Gauhati University, Guwahati-781 014, Email: skarmakar@gauhati.ac.in) : Crystal and molecular structure of 2-thiobenzylazobenzene (C₁₉H₁₆N₂S). Indian J pure appl Phys 2009, 47(12), 863-6.

The title compound (I, W=X=Y=H, Z = CH2Ph) is a divalent organosulphur compound of the type Ar-S-Z belonging to the class of ortho mercaptoazo compounds. The azo group is moved away from the sulphenyl sulphur atom to attain the stable trans azo configuration. The sulphur atom has used hybrid orbitals (sp3) and not pure p-orbitals for the bond formation. The benzyl units attached to the sulphenyl sulphur and the 2-benylazo unit are moved away from each other for steric reason. The molecule is as a whole non-planar but N1 and N2 atoms are coplanar with the respective phenyl rings to which they are attached. The S1 atom is coplanar with the phenyl group to which it is attached. The dihedral angle between the mean planes passing through the atoms of the thiophenyl group and the benzyl group is 75(1)°. There is no intermolecular hydrogen bond and the molecule is stabilised by the network of Van der Waal's interaction in their crystalline assembly.

003061   Kalaivani T;Krishnan S (Physics Dep, S R M University, Kattankulathur-603 203, Email: tkv_p@ryahoo.com) : Dielectric relaxation studies of ternary liquid mixtures of aniline and substituted anilines with acrylonitrile in the microwave region. Indian J pure appl Phys 2009, 47(12), 880-2.

Dielectric behaviour of three amines and their mixtures: N-methyl aniline + acrylonitrile, aniline + acrylonitrile and N,N-dimethyl aniline + acrylonitrile at microwave frequency 9.36 GHz has been studied at temperature 303 K. Different dielectric quantities like dielectric constant (e<155>), dielectric loss (e<155><155>), static dielectric constant (e_°), and dielectric constant at optical frequency (e_∞) have been determined. The relaxation time (τ) has been calculated by both Higasi's method and Cole-Cole method. The molar free energy of activation (ΔF_τ) and (ΔF_η) have also been calculated. The complex systems studied show the maximum relaxation time values at 1:1 complex ratio by both Higasi's method and Cole-Cole plot method.

003060   Jat R N;Chaudhary S (Mathematics Dep, University of Rajasthan, Jaipur-302 004, Email: khurkhuria_rnjat@yahoo.com ) : Magnetohydrodynamic boundary layer flow past a porous substrate with Beavers-Joseph boundary condition. Indian J pure appl Phys 2009, 47(9), 624-30.

Flow of an electrically conducting fluid past a porous substrate attached to the flat plate with Beavers-Joseph boundary condition under the influence of a uniform transverse magnetic field has been studied. Taking suitable similar variables, the momentum equation is transformed to ordinary differential equation and solved by standard techniques. The energy equation is solved by considering two boundary layers, one in the porous substrate and the other above the porous substrate. The velocity and temperature distributions along with Nusselt number are discussed numerically and presented through graphs.

003059   Hayat S S;Choudhry M A;Hussain A;Alam S;Ahmad S A;Ahmad I (Physics and Astronomy Dep, Hazara University, Mansehra, Pakistan, Email: sikandariub@yahoo.com) : Nanoscale relaxation near twin-interfaces of palladium and platinum. Indian J pure appl Phys 2009, 47(10), 730-6.

Molecular dynamics simulation technique with many-body and semi-empirical potentials, based on the embedded atom method is employed to calculate some low index (111), (311), (211) and (210) twin-boundaries at various temperatures. Multilayer relaxation near these twin interfaces for Pd and Pt has also been investigated. For all interfaces except (111), due to high atomic density of (111) plane, considerable relaxation is found on both sides of the interfaces with the same magnitude. The interlayer relaxation near (311) and (211) interfaces is in oscillatory order while near (210) interface is of random nature. Maximum contraction 84.16% and 83.18% for 2nd interplanar spacing is found for Pd and Pt, respectively. This shows partial coalescence of the planes near (211) twin interface. Furthermore, percentage registry relaxation is calculated for the planes in the vicinity near the interfaces.

003058   Gokula Nand;Munish Kumar (Physics Dep, G B Pant University of Agriculture and Technology, Pantnagar-263 145, Email: munish_dixit@yahoo.com) : Temperature dependence of bulk modulus of minerals using equation of state. Indian J pure appl Phys 2009, 47(12), 867-71.

Unified theory of isobaric equation of state (EOS) has been used to obtain the temperature dependence of V/V₀ of ten minerals. The model has been found to give the results in good agreement with the experimental data. The maximum deviations have been found to be less than 1% (except Mg₂SiO₄). A more critical test is provided by computing the temperature dependence of bulk modulus by using the V/V₀ data obtained in the study. Computed values of bulk modulus present a good agreement with the experimental data. This supports the validity of the simple model for complicated minerals. It is concluded that a simple model is capable to predict the properties of minerals under high temperature conditions.

003057   Ghosh D;Deb A;Biswas S;Mandal P;Sarkar R (Nuclear and Particle Physics Research Centre, Physics Dep, Jadavpur University, Kolkata-700 032, Email: deegee111@gmail.com) : Levy index analysis in relativistic and ultrarelativistic nuclear collision - evidence of non-thermal phase transition. Indian J pure appl Phys 2009, 47(12), 839-43.

Analysis on Levy index of compound hadrons (pions + protons) emitted from ^{12C-AgBr and 24Mg-AgBr interactions both at 4.5 AGeV/c and 32S-AgBr interactions at 200 AGeV/c using the results of Takagi moment methodology in emission angle (cosq) space and azimuthal angle (f) space has been presented. The results of the study reveal non-thermal phase transition at both relativistic and ultrarelativistic energy.}

003056   Ghosh D;Deb A;Bhattacharyya S;Datta U (Nuclear and Particle Physics Research Centre, Physics Dep, Jadavpur University, Kolkata-700 032, Email: swarna_pratim@yahoo.com) : Multifractality assessment in high energy nuclear collisions with levy index in self affine scenario. Indian J pure appl Phys 2009, 47(11), 761-71.

Degree of multiplicity assessment with Levy stable index in the target fragmentation of ^{28Si-AgBr interactions at 14.5 AGeV, 32S-AgBr interactions at 200AGeV and 16O-AgBr interactions at 60AGeV in emission angle space and azimuthal angle space separately and also in two dimensional anisotropic (cosθ-φ) space has been studied. The analysis reveals that the values of Levy index lie within 1 and 2. For all the three interactions and for all the cases the values of Levy indices are different suggesting different degree of multifractality in different interactions.}

003055   El-Batal F H (Glass Research Dep, National Research Center, Dokki, Cairo, Egypt, Email: fh_elbatal @yahoo.co.uk.) : UV-visible, infrared, Raman and ESR spectra of gamma-irradiated TiO₂-doped soda lime phosphate glasses. Indian J pure appl Phys 2009, 47(9), 631-42.

Undoped and TiO₂-doped soda lime-phosphate glasses were prepared. UV-visible, infrared, Raman and electron spin resonance spectroscopic studies of the prepared samples, with varying compositions and increasing TiO₂ contents, were measured before and after successive gamma irradiation. The parent undoped glass reveals strong UV absorption originating from trace iron impurities. Experimental data indicate that titanium ions are involved in two valencies in such glasses, namely the trivalent and pentavalent states. The trivalent titanium (Ti³⁺) ions are characterized by its purple colour and showing characteristic two visible absorption bands and paramagnetic ESR character. The tetravalent titanium (Ti⁴⁺) ions belong to the d° configuration and possess only charge transfer ultraviolet absorption interfering with the UV bands due to trace iron impurities as evidenced in the undoped specimen. Glasses with high TiO₂ contents show retardation or shielding effect towards successive gamma irradiation. The changes in the UV, visible and infrared absorption spectra are interpreted in relation to the generation of induced defects by irradiation and the response of the change in glass composition or TiO₂ content. Raman and ESR measurements support the proposed interpretations of the experimental results.

003054   Duhan S (Materials Science Lab, Applied Physics Dep, Guru Jambheshwar University of Science & Technology, Hisar-125 001, Email: surender6561@yahoo.co.in) : Effect of sintering time on particle size of rare earth compounds (R = Nd) prepared by wet chemical method. Indian J pure appl Phys 2009, 47(12), 872-5.

Microstructure of nanocrystalline Nd₂O₃ supported on amorphous SiO₂ upon heat treatment in air at 700°C for 8-32 h has been studied by means of X-ray diffraction (XRD), Fourier transformation infrared (FTIR) and scanning electron microscopy (SEM). It has been found that the annealing time and sintering temperature played a pivotal role to obtain hexagonal and cubic neodymium oxide. The sample calcined at constant sintering temperature 700°C for 32 h was cubic Nd₂O₃ nanocrystallites with average size ~10 nm.

003053   Chakraborty S;Roy A K (Physics Dep, Visva Bharati University, Santiniketan-731235, Email: subrata502002@yahoo.co.in ) : S-wave quarkonia spectroscopy in a relativistic quark model. Indian J pure appl Phys 2009, 47(9), 648-54.

S-wave spectroscopy of mesons in a relativistic quark model given recently for explaining the P-wave data of mesons has been studied.The recent data on S-wave spectroscopy can be explained by the relativistic modification of the scalar-vector model of confinement proposed earlier.

003052   Bi Y;Chen L;Sun F (Institute of Civil & Architectural Engineering, Beijing University of Technology, Beijing 100 124, P R China, Email: lgchenna@yahoo.com) : Ecological, exergetic efficiency and heating load optimizations for irreversible variable-temperature heat reservoir simple air heat pump cycles. Indian J pure appl Phys 0000, 47(12), 852-62.

Thermodynamic optimization of an irreversible air heat pump with variable-temperature heat reservoirs and hot- and cold-side counter-flow heat exchangers has been studied. The expressions of the heating load, the exergetic efficiency and the ecological function of the heat pump cycle are derived. Performance comparisons among exergetic efficiency optimization, ecological optimization and traditional heating load optimization objectives are done. The effect of the pressure ratio of the compressor, the allocation of heat exchanger inventory and the heat capacity rate matching between the working fluid and the heat reservoirs on the optimal performance of the cycle has been investigated by detailed numerical examples. When the performance optimization of the cycle is carried out by selecting the pressure ratio, three optimization objectives give simultaneously attention to the coefficient of performance (COP). The pressure ratio should be the one that is little bigger than the optimum pressure ratio corresponding to maximum COP, however, the results of three optimization objectives are consistent by optimizing the allocation of heat exchanger inventory and optimizing the heat capacity rate matching between the working fluid and the heat reservoirs. The optimum allocations of heat conductance are close to each other, and they are all less than 0.5. The results may provide guidelines for the design and optimization of practical air heat pump plants.

003051   Bhuiyan M R A;Saha D K;Firoz Hasan S M (Applied Physics, Electronics and Communication Engineering Dep, Islamic University, Kushtia 7003, Bangladesh, , Email: mrab_iu@yahoo.com ) : Structural and electrical properties of polycrystalline Ag_xGa_2-xSe₂ (0.4≤x≤1.6) thin films. Indian J pure appl Phys 2009, 47(11), 787-92.

Thin films of Ag_xGa_2-xSe₂ (AGS) have been prepared onto glass substrates by stacked elemental layer (SEL) deposition technique in vacuum. The atomic composition of the films has been measured by energy dispersive analysis of X-ray (EDAX) method. The structural and electrical properties of the films are ascertained by X-ray diffraction (XRD) and standard dc method using a cryostat, respectively. The structural and electrical parameters have been found for different non-molecularity of the films. The films ascertain the compositional uniformity. The X-ray diffraction (XRD) reveals that the films are polycrystalline in nature. The electrical conductivity of the films (at room temperature) having different non-molecularity has been found to vary from 1.36x10^-6 to 4.93x10^-3 (<872>-cm)^-1. These films support thermally activated process. The activation energies vary between 21.61 and 60.64 meV as non-molecularity varies between -0.798 and 1.710.

003050   Bhaskar R;Lakshmanan A R;Sundarrajan M; Ravishankar T;Jose M T;Lakshminarayan N (Physics Dep, Saveetha Engineering College, Thandalam, Chennai-602 105, Email: arunachalamlakshmanan@yahoo.com) : Mechanism of green luminescence in ZnO. Indian J pure appl Phys 2009, 47(11), 772-4.

ZnO grown under reducing condition is always Zn excess. These Zn atoms are positioned at interstitial sites due to the escape of oxygen from ZnO. The oxygen vacancies created by alkali metal dopants in ZnO play a major role in its green luminescence. This is understood on the basis of charge transfer between Zn interstitials and neighbouring oxygen vacancies caused by the doping of monovalent ions such as Li, Na or K at divalent Zn lattice sites followed by Stokes shifted emission.

003049   Bansal V;Bhandari H;Bansal M C;Dhawan S K (Polymeric & Soft Materials Section, National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110 012, Email: skdhawan@mail.nplindia.ernet.in) : Electrical and optical properties of poly(aniline-co-8-anilino-1-napthalene sulphonic acid) - a material for ESD applications. Indian J pure appl Phys 2009, 47(9), 667-75.

Homopolymer of aniline (An) and its copolymer with 8-anilino-1-napthalene suplhonic acid (8-ANSA) was synthesized by chemical oxidative as well as electrochemical polymerization process in the presence of para-toluene sulphonic acid (PTSA) as a dopant. The spectral, thermal, morphological and electrochemical properties of PTSA doped polyaniline and its copolymer (An-co-8-ANSA) were studied and compared to elucidate the effect of the inclusion of 8-ANSA in the copolymer feed. The resultant copolymer showed better solubility and processibility but this approach usually results in the lowering of conductivity, hence the ratio of aniline and 8-ANSA in the copolymer feed was selected to 80:20. The room temperature conductivity of the PTSA doped polyaniline (PANI-PTS) and poly(An-co-8-ANSA) in 80:20 was found to be in the order of 1.74 S/cm to 9.77x10^{-1 S/cm, respectively. Conductivity mechanism of charge transport has been investigated in the range 30-300K. In the temperature range 30-70 K, copolymer showed tunneling mechanism. However, above 70 K conductivity attributes to Mott's variable range hopping (VRH) mechanism. The electrochemical behaviour of the polymers was studied by cyclic voltametry. The structure of the copolymer is characterized by 1H NMR spectroscopy, UV-visible and FTIR spectroscopy. Electrostatic charge dissipation (ESD) of the conducting copolymer blend was also studied by blending of 1% of PTSA doped polyaniline and poly(aniline-co-8-ANSA) with LDPE which shows a static decay time of 0.1 to 0.25 sec on dissipating the charge from 5000 to 500 V.}

003048   Balachandran V;Kandiban G (Physics Dep, A A Government Arts College, Musiri, Tiruchirappalli-621 201, Email: brsbala@rediffmail.com) : Experimental and numerical realization of higher order autonomous Van der Pol-Duffing oscillator. Indian J pure appl Phys 2009, 47(11), 823-7.

The application of the hyperchaotic dynamics will enhance the engineering system such as chaos based security of communication in information technology. Interest in such systems has been increasing. Some interesting phenomena of higher order autonomous Van der Pol-Duffing oscillator based on fifth order hyperchaotic circuit to improve secure communication have been studied in the present paper. This circuit, which is capable of realizing the behaviour of every member of the autonomous Van der Pol-Duffing family, consists of just six linear elements (resistor, inductors and capacitors) and a smooth cubic non-linearity. In this circuit, we can confirm period doubling routes to chaos and then to hyperchaos through boundary condition, when the system parameter varies. The hyperchaotic dynamics, characterized by broad band power spectrum, is presented to confirm the hyperchaotic nature of the oscillations of the circuit. This has been investigated extensively using laboratory experiments and numerical integration of the appropriate differential equations.

003047   Arslanalp R;Tola A T (Faculty of Engineering, Electrical and Electronics Engineering Dep, Pamukkale University, 20070, Kinikli, Denizli, Turkey, Email: rarslanalp@pau.edu.tr ) : State space representation for log domain filtering synthesis. Indian J pure appl Phys 2009, 47(10), 745-52.

New method for the state space representation of filters based on the companion form technique has been proposed. It is useful for synthesis of log domain filters. For state space representation of a log domain filter, it is very important to have almost equal coefficients of the state space equations since these coefficients are proportional to currents or voltages of the designed device. The method allows selection of two arbitrary parameters (α,β) to adjust these coefficients. By using this technique, more balanced state space equations can be obtained. This method offers an option to obtain desired adjustable coefficients. It is particularly useful for synthesizing high order log domain circuits using state space methods. The proposed method is applied to second and fifth order log domain filter designs to show the application. Simulation results demonstrated that different system equations which are determined by the proposed method affect the performance of the filter.

003046   Agrawal S K (Mathematics Dep, R S P College, Jharia, Dhanbad, Jharkhand) : Alpha spectra and Yukawa potential as static part of the barrier. Indian J pure appl Phys 2009, 47(12), 889-91.

Yukawa potential has been applied as static part in the non - local α-nucleus potential to calculate the relative intensities of the α-spectra of some rare earth and heavy nuclei. The results are found to be in good agreement with the observed values.

002055   Varalaxmi N;Venkata Ramana M;RamamaNohar Reddy N (Ceramic Composite Materials Laboratory, Physics Dep, Sri Krishnadevaraya Univ, Ananthapur-505 003) : Elastic behavior and internal friction loss of NiMgCuZn ferrospinels for microinductor applications. J pure appl Ultrasonics 2007, 29(4), 133-8.

Two series of NiMgCuZn ferrites namely 1) Ni_xMg_0.6-xCu_0.1Zn_0.3 Fe₂O₄ with x= 0.0,0.1,0.2,0.3; 2)Ni_0.35Mg_0.2-yCu_0.05Zn_0.5-yFe₂O₄ with y= 0.0, 0.1, 0.2 were prepared by conventional double sintering process with a view to examine their use as core materials for microinductor applications. The x- ray analysis revealed the single phase formation. In order to examine their elastic behaviour, the temperature variation of longitudinal modulus and acoustic loss (Q^-1) of these samples at 142 kHz were studied in temperature range 300 to 630 K using composite resonator technique. The longitudinal modulus showed an abrupt break near curie temperature transition in all the samples studied in the present work. The temperature variation of internal friction loss (Q^-1) showed a corresponding stress induced relaxation peak at this phase transition. The results are explained in the light of structural phase transition.

3 illus, 2 tables, 11 ref

002054   Sudar Mozhi G;Ramanathan K (Physics Dep, Muthayammal Engineering College, Rasipuram, Tamil Nadu) : Intermolecular interactions in binary mixtures of lithium hydroxide and litium sulphate. J pure appl Ultrasonics 2007, 29(4), 139-42.

In this study the Ultrasonic velocity and density of different proportionate mixture of Lithium Hydroxide (LiOH) and Lithium Sulphate (Li₂SO₄ are determined in the frequency range of 3MHz at room temperature using ultrasonic interferometer technique. With the values of velocity and density, the parameters like adiabatic compressibility, inter molecular free length, acoustical impedance, molar sound velocity, molar compressibility and molar volume have been calculated. It is observed that there is a complex nature of the mixture at a particular definite concentration.

4 illus, 2 tables, 8 ref