023116   Karahan I H;Bakkaloglu O F;Bedir M (Phys Dep, Faculty of Kilis Sci and Arts, University of Gaziantep, 79100 Kilis, Turkey, Email: ikarahan@gantep.edu.tr) : Giant magnetoresistance of electrodeposited Cu-Co-Ni alloy films. Pramana J Phys 2007, 68(1), 83-90.

Electrodeposition of CuCoNi alloys was performed in an acid-citrate medium. Nickel density parameter was varied in order to analyse its influence on the magnetoresistance. The structure and giant magneto- resistance (GMR) effect of CuCoNi alloys have been investigated. The maximum value for GMR ratio, at room temperature is 1% at a field of 12 kOe, and at 20 K is 2.1 at a field of 8.5 kOe for 3.1 Ni. The MR ratio of CU_lOO-y-xCo_yNi_x alloys first increases and then decreases monotonically with increasing Ni content. The GMR and its dependence on magnetic field and temperature were discussed.

7 illus, 16 ref

023115   Kannappan V;Indra Gandhi N (Postgraduate and Research Department of Chemistry, Presidency College, Chennai-600 005) : Ultrasonic studies on charge transfer complexes of certain aldehydes with benzylamine and cyclohexylamine as donors in n-hexane at 303K. Indian J pure appl Phys 2007, 45(3), 221-5.

Ultrasonic velocities (U), densities (ρ), and viscosities (η) were measured for solutions containing equimolar. concentrations of eight aldehydes namely, benzaldehyde, o-chlorobenzaldehyde, anisaldehyde, p-tolualdehyde, cinnamaldehyde, crotonaldehyde, propionaldehyde, and valeraldehyde as acceptors, benzylamine and cyclohexylamine as donors in n-hexane at 303K. Acoustical parameters such as adiabatic compressibility (β), free length (L_f), viscous relaxation time (r), molecular interaction parameter (χ_u) have been computed. These values indicate the formation of charge transfer complexes between aldehydes and amines. Formation constant (K) values of the complexes have been evaluated using a modified Bhat equation proposed by Kannappan. The constant values of free energy of activation (Δ G<35>) and relaxation time indicate the formation of similar type of complexes in these systems. However, the variation in free energy of formation (Δ G) values suggests that their thermodynamic stability depends on the structure of donor and acceptor.

4 tables, 6 illus, 13 ref

023114   Kandpal D;Gupta B R K (Phys Dep, G.B. Pant Univ of Agric and Technol, Pantnagar-263 145, Email: d_kandpal77@rediffmail.com) : Analysis of thermal expansivity of iron (Fe) metal at ultra high temperature and pressure. Pramana J Phys 2007, 68(1), 129-34.

Explains the thermal and compression properties of HCP iron (Fe) at high pressure with variable temperature (isobars) and at high temperature with variable pressure (isotherm). The usual Tait equation of state is modified by incorporating the effect of thermal pressure. The calculated values of pressure for different isotherms and isochors and thermal expansivity (α) as a function of both temperature and pressure have been compared with those values obtained by Isaak et al and Wasserman et al.

4 illus, 18 ref

023113   Joshi N C;Verma A;Nitendar Kumar;Satheesh Kumar O B;Islam S S (Jamia Millia Islamia, , New Delhi-110 025) : Nickel-substituted lithium-zinc-manganese ferrite for the suppression of radiated emission noise. Def Sci J 2007, 57(4), 617-26.

Nickel-substituted lithium-zinc-manganese ferrite of the composition, Li_0.25-x/4Zn_0.5-x/2Ni_xMn_0.1 Fe_2.15-x/4O₄ where x = 0, 0.1,0.2, 0.3, 0.4, 0.5 have been investigated for electromagnetic interference (EMI) suppression to meet the EMI standards. Various compositions were prepared by the conventional ceramic technique using mixed oxides. The ferrites were characterised for their structural, electrical, and magnetic, properties. The ferrites were found to possess high saturation magnetisation, permeability, Curie temperature and resistivity, which are the desirable characteristics for noise-suppression application. The operating frequency of the ferrite ranged from 1 MHz to 700 MHz, which is high enough for absorbing the electrical fast transients and radiated emission noise suppression as shown for three devices-currency counting machine, energy meter and dc-dc converter where the radiated emission noise is suppressed from 10 dB to 20 dB. In energy meter the electrical fast transients (EFTs) are suppressed up to 5.5 kV, 4.5 kV, 3.5 kV, 2.8 kV, 1.6 kV, and 1.2 kV with composition x= 0,0.1,0.2,0.3,0.4,0.5, respectively. This material has tremendous scope of application in military equipment to comply the EMI requirements of the military standards.

1 table, 12 illus, 19 ref

023112   Jadhav L D;Pawar S H;Chourashiya M G (Physics Dep, Shivaji Univ, Kolhapur-416 004) : Effect of sintering temperature on structural and electrical properties of gadolinium doped ceria (Ce_0.9Gd_0.1O_1.95. Bull Mater Sci 2007, 30(2), 97-100.

Gadolinium doped ceria oxide is one of the promising materials as an electrolyte for IT-SOFCs. Ce_0.9 Gd_0.1 O_1.95 (GDC10) powder was prepared by solid state reaction and sintered at 1473 K, 1573 K, 1673 K and 1773 K. All samples were studied using X-ray diffraction, scanning electron micrograph and d.c. conductivity measurement. The crystallinity and surface morphology of the samples improved with sintering temperature. Further, the electrical conductivity measurement indicated that the conduction mechanism is mainly ionic. The conductivity of samples sintered at 1673 K and 1773 K at 800°C are of the order of 0.1 S-cm^-1. The activation energies decreased from 1-25-0.82 eV with increase in sintering temperature.

1 table, 6 illus, 25 ref

023111   Ivanda M;Tonejc A M;Djerdj I;Montagna M; Ferrari M;Righini G;Berneschi S;Crnjak Orel Z;Schmitt M (NO, Rudjer Boskovic Institute, P.O. Box 180, 10002 Zagreb, Croatia, Email: Ivanda@rudijer.irb.hr) : Raman scattering determination of size distribution of CdS_zSe_1-x. Asian J Phys 2006, 15(2), 195-200.

The Raman scattering spectra of CdS_xSe_l-x nanoparticles embedded in glass matrix are analyzed in a model of confined acoustical vibrations. The model-calculation considers the homogenous broadening of the confined acoustical modes, due to the interaction of the particles with the matrix, and the inhomogeneous broadening, due to the contribution of the Raman scattering from particles of different sizes. Assuming a log-normal distribution for the particle size, the experimental shape of the low frequency peak is fitted by the model obtaining the mean size and the width of the size distribution. The Raman results well compare with the TEM results, showing that Raman scattering is a simple fast technique for the determination of the size distribution of nanoparticles. PACS number's: 33.20.Fb, 33.20.Tp, 68.65.Hb.

5 illus, 26 ref

023110   Hermanz A;Gavira J M;Ruiz-Lopez J F (Departamento de Ciencias y Tecnicas Fisicoquimicas, Facuked de Cienci, Universidad Nacional de Educacion a Distancia (UNRD), Senda del Rey, 9, E-28040 Madrid, Spain, Email: ahernanz@ccia.uned.es) : Application of Raman microscopy to the study of prehistoric rock paintings. Asian J Phys 2006, 15(2), 187-93.

Raman microscopy is a very useful technique to identify the nature of the pigments used in prehistoric rock paintings. The composition of the substrata and possible accretions or alterations, as well as conservations problems may also be investigated. The applied methodology using this microspectroscopic technique for these studies is described. Some results obtained on prehistoric pictographs from rock shelters of the Sierra de las Cuerdas (Cuenca, Spain) are presented.

6 illus, 36 ref

023109   Gurpreet Singh;Kumar P;Thulkar S (Radiodiagnosis Dep, Medical Physics Unit, Dr BRA Institute Rotary Can, All India Institute of Medical Sciences, New Delhi-110 029, Email: drpratikumar@hotmail.com) : Importance of quality control in diagnostic ultrasound : a preliminary study. J pure appl Ultrasonics 2006, 28(1), 29-32.

The benefit of ultrasonography (US) is multifold and exceptional since it uses non-ionizing radiation and therefore even unborn fetus may be exposed to it repeatedly. However, this unbridled use of US places greater responsibility on the proper functions of all its parameters. To break this notion and establish a viable quality assurance program in ultrasound imaging the authors carried out quality assurance tests on two US machines. This paper sums up the preliminary experience of these Quality Assurance tests.

1 table, 1 illus, 6 ref

023108   Grafe S;Tarcea N;Engel V;Schlucker S (NO, Institut fur Physikalische Chemie, Universitat Wurzburg, Am Hubland, 97074 Wurzburg, Germany, Email: sebastian.schluecker@mail.uni-wuerzburg.de ) : Mode selective probing of ground state vibrational dynamics in a hydrogen-bonded binary mixture by polarization-sensitive femtosecond time-resolved multiplex CARS. Asian J Phys 2006, 15(2), 179-86.

Presents experimental and theoretical data for polarization-sensitive (PS) femtosecond time-resolved multiplex coherent anti-Stokes Raman scattering (fs-MCARS) spectroscopy on a hydrogen-bonded binary mixture of pyridine and water in the electronic ground state. The spectrally dispersed detection of the CARS signal allows to simultaneously probe the vibrational coherence dynamics and, after the application of Fourier transform methods to the time domain signal, to determine the relative spectral positions of the excited vibrations. Firstly compares the experimental fs-MCARS transient obtained under magic angle polarization conditions for suppression of non-Raman resonant contributions with simulated data from a theoretical description of fs-MCARS spectroscopy based on the time-dependent third-order non-linear polarizability P⁽³⁾(t). The theoretical transient reproduces the characteristic structure of the experimentally observed CARS signal, for example, the multiple quantum beats between pairs of the three coherently excited pyridine ring modes. Secondly demonstrates theoretically that mode specific probing of ground state vibrational dynamics is achievable In a PS fs-MCARS experiment because individual CARS signal contributions can be suppressed at certain analyzer positions. The corresponding oscillatory components in the overall CARS signal involving this particular vibration vanish, resulting in the detection of ground state dynamics of a subset of vibrations.

6 illus, 37 ref

023107   Ghosh M;Chowdhury J (Spectroscopy Dep, Indian Ass for the Cultivation of Sci, Jadavpur, Kolkata-700 032, Email: joydeep72_c@redifmail.com) : Concentration dependent surface-enhanced Raman scattering of molecules adsorbed on collidal silver particles : a brief overview. Asian J Phys 2006, 15(2), 149-58.

A brief review on the concentration dependent Surface-enhanced Raman scattering (SERS) studies of isomeric benzoyl pyridines, porphyrin-l0 and 2-amino benzothiazole molecules adsorbed on silver hydrosol has been described. The variations in the SERS spectral profile of the above mentioned molecules with the adsorbate concentrations have been attributed to the change in the orientation of the molecule on the colloidal silver surface.

^iia4 illus, 49 ref

023106   Ghoranneviss M;Shokouhy A;Larijani M M;Haji Hosseini S H;Yari M;Anvari A;Gholipur Shahraki M;Sari A H;Hantehzadeh M R (Plasma Phs Res Center, , Sci and Res Campus of Islamic Azad Univ, P.O. Box 14665-678, Tehran, Iran) : Corrosion behavior of low energy, high temperature nitrogen ion-implanted AISI 304 stainless steel. Pramana J Phys 2007, 68(1), 135-40.

Presents the results of a low-energy nitrogen ion implantation of AISI 304 type stainless steel (SS) at a moderate temperature of about 500°C. The nitrogen ions are extracted from a Kauffman-type ion source at an energy of 30 keV, and ion current density of 100 μA cm^-2. Nitrogen ion concentration of 6 x 10¹⁷, 8 X 10¹⁷ and 10¹⁸ ions. Cm^-2, were selected for the study. The X-ray diffraction results show the formation of CrN polycrystalline phase after nitrogen bombardment and a change of crystallinity due to the change in nitrogen ion concentration. The secondary ion mass spectrometry (SIMS) results show the formation of CrN phases too. Corrosion test has shown that corrosion resistance is enhanced by increasing nitrogen ion concentration.

3 illus, 2 tables, 12 ref

023105   Ganguly P;Biswas J C;Lahiri S K (Integrated Optics Laboratory, Advanced Technology Centre, Indian Institute of Technology, Kharagpur-721 302, Email: pran@ece.iitkgp.ernet.in) : Design of single mode annealed proton exchanged LiNbO₃ waveguides by effective-index based matrix method. J Optics 2006, 35(1), 51-62.

Effective-index based matrix method is used to analyse annealed proton exchanged (APE) LiNbO₃ waveguides. The variation of refractive index with the fabrication parameters, such as, exchange time, annealing time, waveguide width, and transmit ting wavelength is studied. The computed surface refractive index changes of the waveguides are compared with the published experimental results. The 2D transverse refractive index profile of the APE lithium niobate waveguide is transformed to the laterial ID effective index profile by WKB method, which is then discretised using a partitioning scheme. The matrix method is then applied to obtain the propagation constants of the guided modes. Variation of propagation constant with the fabrication parameters of APE waveguide is studied and the single mode APE lithim niobate channel waveguides are designed.

2 table, 5 illus, 22 ref

023104   Gaikwad S A;Samuel E P;Patil D S;Gautam D K (Electronics Dep, Nort Maharashtra Univ, Jalgaon-425 001, Email: israel_jal@sancharnet.in) : Temperature dependent analysis of refractive index, band gap and recombination coefficient in nitride semiconductor lasers. Indian J pure appl Phys 2007, 45(3), 238-42.

Temperature dependent analysis of recombination coefficient, band gap and refractive index has been carried out to explore applicability of nitride lasers at higher temperatures. To estimate recombination coefficient at various temperatures Shockley-van Roosbroeck model has been used. Results reveal that refractive index increases in linear manner with temperature and indium mole fraction in InGaN. However, refractive index was found to be decreasing with Al mole fraction and temperature in non-linear manner. The band gap deduced from our analysis was found to be increasing with Al mole fraction and decreasing with In mole fraction and therefore, these alloys provide better opportunity to form effective heterostructures with GaN. The recombination coefficient analysed, was observed to be decreasing non-linearly with band gap and temperature for AlGaN. However, in case of InGaN, the recombination coefficient shows linear increase with band gap and non-linear decrease with temperature.

5 illus, 20 ref

023103   Farcau C A;Astilean S (Phys Faculty, Babes-Bolyai Univ, M. Kogalniceanu 1, 400084 Chuj-Napoca, Romania) : Silver film ddeposited on colloidal crystals template as high sensitivity SERS substrate. Asian J Phys 2006, 15(2), 159-65.

Silver nanostructured tilms were prepared by metal deposition on top oftwo-dimensional colloidal crystal. Their optical properties, investigated by transmission measurements, are correlated with surface enhanced Raman spectra. Finds that Raman signal is greatly enhanced at wavelengths at which the phenomenon of enhanced transmission is observed.

4 illus, 31 ref

023102   El-Taher A El;Mahmoud H M;Abbady A G E (Physics Dep, Faculty of Science, Al-Azhar Univ, Assuit, Egypt) : Comparative study of attenuation and scattering of gamma-rays through two intermediate rocks. Indian J pure appl Phys 2007, 45(3), 198-203.

With the extensive applications of radioactive materials, it is necessary to look for locally available and cheep materials to be efficient absorbers appropriate for shielding from radiation hazards. The attenuation and scattering coefficients of gamma-rays of different energies in thirty samples from two igneous rocks: diorite and andesite, the effects of sample density, p, with radiation energy (E) ranging from 0.36 to 1.33 MeV, were investigated by using a scintillation detector Nal (Tl). The chemical composition of major elements measured by X-ray fluorescence (XRF). The results showed an inverse proportionality between the linear attenuation coefficient μ and E, and μ has a direct proportionality with the sample density, p. The side scattering coefficient φ, is directly proportional to Eγ, but at the same time φ has an inverse proportionality with the sample density. The results showed an inverse proportional between the half value layers and the sample density p.

8 tables, 6 ref

023101   Durai S;Ramadoss P (Pysics P.G. & Research Dep, A.M. Jain College, Chennai-600 114) : Role of kinetic theory in the study of liquefied gases. J pure appl Ultrasonics 2006, 28(1), 1-3.

Attempted to bring out such common characteristics applying kinetic theory of liquids and gases to ten liquefied gases and the results are briefly analyzed.

2 illus, 10 ref

023100   Devi R;Purkayastha P;Kalita P K;Sarma B K (Physics Dep, Gauhati Univ, Guwahati-781 014, Email: kuhkhal@yahoo.com) : Synthesis of nanocrystalline CdS thin films in PVA matrix. Bull Mater Sci 2007, 30(2), 123-8.

Nanocrystalline thin films of CdS are deposited on glass substrates by chemical bath deposition technique using polyvinyl alcohol (PVA) matrix solution. Crystallite sizes of the nanocrystalline films are determined from broadening of X-ray diffraction lines and are found to vary from 5.4-10.2 nm. The band gap of the nanocrystalline material is determined from the UV spectrograph. The absorption edge is shifted towards the lower wave length side (i.e. blue shift) and are found to be within the range from 2.48-2.8 eV as grain sizes decrease from 10.2-5.4 nm. This is also supported by the spectral response curves. An increase of molarity decreases the grain size which in turn increases the band gap.

6 illus, 20 ref

023099   Das S S;Satapathy A;Das J K;Sahoo S K (Physics Dep, KBDAV Coll, Nirakarpur, Khurda-752 019) : Numerical solution of unsteady free convection MHD flow past an accelerated vertical plate with suction and heat flux. Ultra Scient phys Sci 2007, 19(1), 105-12.

Considers the unsteady free convective MHD boundary layer flow of a viscous incompressible electrically conducting fluid past an accelerated infinite vertical plate with suction and heat flux. The governing equations are solved both analytically and numerically using derror function and finite difference scheme. The flow phenomenon has been characterized with the help of flow parameters such as, suction parameter (a), magnetic parameter (M), Grashof number for heat transfer (G_rr). The effects of these parameters on the velocity field, temperature field, skin friction and heat flux have been studied and the results are presented graphically and discused quantitatively. This type of problem has some relvence in the field of geophysical and cosmical studies.

5 illus, 1 table, 16 ref

023098   Chowdhury A;Joshi R A;Naik P A;Gupta P D (Laser Plasma Div, Raja Ramanna Centre for Advanced Technol, Indoe-452 013) : Optimization of C<. Pramana J Phys 2007, 68(1), 43-9.

Parametric dependence of the intensity of 182 Angstrom Balmer-α line (G⁵⁺; n = 3 → 2), relevant to xuv soft X-ray lasing schemes, from laser-produced carbon plasma is studied in circular spot focusing geometry using a flat field grating spectrograph. The maximum spectral intensity for this line in space integrated mode occurred at a laser intensity of 1.2 x 10¹³ W cm^-2. At this laser intensity, the space resolved measurements show that the spectral intensity of this line peaks at <126> 1.5 mm from the target surface indicating the maximum population of C⁵⁺ ions (n = 3), at this distance. From a comparison of spatial intensity variation of this line with that of C⁵⁺ Ly-α (n = 2 → 1) line, it is inferred that n = 3 state of C⁵⁺ ions is predominantly populated through three-body recombination pumping of C⁶⁺ ions of the expanding plasma consistent with quantitative estimates on recombination rates of different processes.

6 illus, 19 ref

023097   Chashechnikova I;Gavrilko T;Puchkovska G; Shaydyuk Y;Lebovka N;Moraru V;Hauser A;Kresse H (NO, Institute of Physics, National Academy of Sci of Ukraine, 46 Nauki Prosp, 03028 Kyiv, Ukraine) : Molecular dynamics and interface interactions in LC-clay suspensions by dielectric spectroscopy and FT-IR analysis. Asian J Phys 2006, 15(2), 167-78.

The dielectric relaxation of a nematic liquid crystal (LC) ZLI-2293 suspension containing anisometric particles of organically modified montmorillonite clay (with two different types of organic modificator, octadecylbenzyldimethylammonium chloride and dioctadecyldimethylammonium chloride) is studied over wide temperature and frequency ranges. Two relaxation ranges are detected for the both LC-clay suspensions. Orientation of LC molecules around their short axes is the mechanism responsible for high-frequency relaxation (ƒ_R <126>2 x 10² Hz). The low-frequency relaxation ƒ_R <126> 2 x 10² Hz) process is caused by Maxwell-Wagner interfacial polarization. By combining the results from the dielectric measurements, those from atomic force microscopy (AFM), and Fourier transform IR spectroscopy (FTIR), the effect of the clay surface structure and the LC-clay interaction on the relaxation behaviour is discussed in terms of different network structure of the two organoclay particles.

7 illus, 1 table, 28 ref

023096   Chandel C;Srivastava P K;Upadhyay A (Snow and Avalanche Study Establishment, , Manali-175 103) : Estimation of rheological properties of snow subjected to creep. Def Sci J 2007, 57(4), 539-47.

Creep behaviour of snow is simulated with four-parameter viscoelastic fluid model. This viscoelastic character is basically controlled or monitored by various rheological constants. Estimation of all the rheological constants in the four-parameter viscoelastic fluid model appropriate for the creep properties of snow is done. Total 91 uniaxial unconfined constant stress experiments on sieved snow were conducted at controlled temperature conditions. The effect of density and varying temperature on these constants is found to be remarkable.

8 illus, 12 ref

023095   Biswas S;Chowdhury I (Phys Dep, Univ of Kalyani, Kalyani-741 235, Email: sbiswas@klyuniv.ernet.in) : Calculation of CWKB envelope in boson and fermion productions. Pramana J Phys 2007, 68(1), 1-19.

Presents the calculation of envelope of boson and of both low- and high-mass fermion production at the end of. inflation when the coherently oscillating inflatons decay into bosons and fermions. Considers three different models of inflation and use CWKB technique to calculate the envelope to understand the structure of resonance band formation. Observs that though low-mass fermion production is not effective in preª heating because of Pauli blocking, it is quite probable for high-mass fermion to take part in pre-heating.

8 illus, 11 ref

023094   Binu S;Mahadevan Pillai V P;Chandrasekaran N (Optoelectronics Dep, Kerala Univ, Thiruvananthapuram-695 581) : OTDR based fiber optic microbend sensor for distributed sensing applications in structural pressure monitoring. J Optics 2006, 35(1), 36-44.

Ability to understand and monitor the distributed behaviour of extended, critical structures is recognized as a matter of increasing importance. Optical fibres offer unique advantages for spatially distributed measurement. An especially important feature is the one dimensional nature of the medium, since this offers unique advantages for spatially distributed measurement. Describes the principle of operation, the design and performance of a novel single mode fiber based multipoint microbend pressure sensor architecture, which may be utilized in distributed measurement. The actual sensor element is a single mode fiber coupled to the measurand field through the usual microbend inducing structures. The sensor uses optical time domain reflectometry (OTDR) to detect pressure induced charges of backscatter power at many separate locations in the fiber as a function of length along a single fiber with no taps or branches. The sensitivity of this structure to microbend induced losses has been thoroughly characterized. This feature greatly increases the information from a single instrument and hence decreases the cost-benefit ratio.

4 illus, 10 ref

023093   Bhatti H S;Gupta A;Verma N K;Sunil Kumar (Physics Dep, Punjabi Univ, Patiala-147 002) : Optical properties of ZnO phosphors activated with Mn And Se impurity. J Optics 2006, 35(1), 45-50.

Various optical parameters of interest have been obtained from the synthesized singly and doubly doped ZnO semiconductor phosphors with variable concentrations of manganese and selenium. Time resolved photoluminescence (PL) spectra have been observed in doped phospors when these are excited by the UV laser radiation, giving rise to emission in the visible region. The phosphors under investigations were exited by UV pulsed N₂ laser (having high peak output power) at room temperature. In present context transition probability, oscillator strength, integrated cross-section and dipole-moment values have been calculated from the laser induced photoluminescence decay curves of the singly and doubly doped ZnO phosphors. In case of doubly doped ZnO phosphors the increasing trend of all the parameters is attributed to the fact that the emission from shallow trapping states plays the dominant role or it may be due to energy transfer mechanism.

4 tables, 14 ref

023092   Bera P K;Datta J (Phys Dep, Dumkal College, Dumkal, Murshidabad-742 303, Email: pbera321@sify.com) : Linear delta expansion technique for the solution of anharmonic oscillations. Pramana J Phys 2007, 68(1), 117-22.

The linear delta expansion technique has been developed for solving the differential equation of motion for symmetric and asymmetric anharmonic oscillators demonstrates the sophistication and simplicity of this new perturbation technique.

11 ref

023091   Bende A;Tosa V (NO, Nation Institute of Research and Development of Isotopic and Molecular, Sti. Donath, No: 71-103, Ro-400293, Cluj-Napoca, Romania) : IR multiphoton absorption spectra of some freon molecules used in <. Asian J Phys 2006, 15(2), 275-9.

A model calculation for the collisionless infrared multiphoton absorption (MPA) has been performed for some freon molecules (CF₂HCl, CF₂Cl₂ and CFCI₃) used in ¹³C laser isotope separation. The harmonic vibrational frequencies and their anharmonic frequency corrections. The MPA spectra correlate well with experimental data for CF₂ HCI and CF₂Cl₂ and reveal the excitation dyriamics in collisionless regime.

3 illus, 2 tables, 14 ref

023090   Bari R H;Patil L A;Soni A;Okram G S (Physics P.G. Dep, Pratap College, Amalner-425 401, Email: lapresearch@rediffmail.com) : Electrical properties of chemically prepared nonstoichiometric CuIn (S, Se)₂, thin films. Bull Mater Sci 2007, 30(2), 135-9.

Polycrystalline thin films of copper indium sulphoselenide [CuIn(S,Se)₂] were deposited on glass substrate by chemical bath deposition technique. The deposition parameters such as pH, temperature and time were optimized. A set of films having different elemental compositions was prepared by varying Cu/In ratio from 1.87-12.15. The films were characterized by X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX). The chemical composition of the CuIn(S,Se)₂ was found to be nonstoichiometric. The d.c. conductivities of the films were studied below and near room temperature. The thermo-electric power of the films was also measured and type of semiconductivity was ascertained.

2 tables, 4 illus, 13 ref

023089   Balaji Rao R;Srinivasa Reddy M;Yadagiri Reddy P;Veeraiah N (Physics Dep, Acharya Nagarjuna University P.G. Centre, Nuzvid-521 201, Email: nvr8@rediffmail.com) : Dielectric and optical properties - structure correlations in NiO doped Li₂O-MgO-B₂O₃ glasses. Indian J pure appl Phys 2007, 45(3), 243-55.

Glasses of the system, Li₂O-MgO-B₂O₃ containing different concentrations of NiO (ranging from 0 to 1.0 mol %) were prepared. A number of studies viz., dielectric properties (constant ε, loss tanδ, ac conductivity σ_ac over a range of frequency and temperature and dielectric breakdown strength) optical absorption, magnetic susceptibility and thermoluminescence on these glasses were carried out as a function of NiO concentration. An anomaly has been observed in all these properties when the concentration of NiO is about 0.6 mol % in the glass matrix. This has been explained in the light variation in the environment of Ni²⁺ ions in the glass network.

6 tables, 14 illus, 46 ref

023088   Baia M;Lupu D;Biris A R (Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania, Email: monib@phys.ubbcluj.ro) : Surface-enhanced and Raman spectroscopy of carbon nanotubes obtained by CCVD method. Asian J Phys 2006, 15(2), 215-20.

The catalytic chemical vapor deposition (CCVD) method with electric outer furnace heating as well as induction heating (lH) was employed for the synthesis of carbon nanostructures. These obtained samples were characterized by Raman spectroscopy, using several excitation energies, and it was found that they are single-wall carbon nanotubes of different diameters in the range 1.1 to 1.7 nm. The samples obtained with the CCVD-IH method are more abundant but they are less pure as compared to those obtained with the conventional CCVD method with outer furnace heating. From the analysis of the Stokes and anti-Stokes Raman and surface-enhanced Raman (SER) spectra it was found that the samples contain a mixture of metallic and semiconducting tubes, with a higher rate for semiconducting ones.

3 illus, 1 table, 19 ref

023087   Baia L;Trandfir V;Danciu V;Baia M;Cosoveanu V;Popp J (Faculty of Phys, Babes-Bolyai Univ, M. Kogalniceanu 1, 400084 Cluj-Napoca, Romania, Email: lich@phys.ubbcluj.ro) : Synthesis and morpho-structural investigations of titania-collagen aerogels based biocomposites. Asian J Phys 2006, 15(2), 201-7.

Titania-collagen aerogels based biocomposites have been prepared. The pores distribution of the Iyophilised samples has been determined and a relationship with the titania content has been found. Optical and vibrational spectroscopic investigations have been performed by means of UV-absorption and FT-IR spectroscopy in order to find the influence of the Ti0₂ on the collagen structure. The fingerprint features of all UV-absorption and FT-IR recorded spectra are specific to the type I collagen. Conformational changes of the collagen proteins caused by the Ti0₂ addition have been evidenced, however the integrity of the triple helicity was found to be unaltered.

3 illus, 1 table, 26 ref

023086   Aygun S;Aygun M;Tarhan I (Phys Dep, Art and Faculty, Canakkale Onsekiz Mart Univ, 17020 Canakkale, Turkey, Email: saygun@comu.edu.tr) : Energy-momentum localization in marder space-time. Pramana J Phys 2007, 68(1), 21-30.

Considering the Einstein, Mo11er, Bergmann-Thomson, Landau-Lifshitz (LL), Papapetrou, Qadir-Sharif and Weinberg's definitions in general relativity, finds the momentum four-vector of the closed Universe based on Marder space-time. The moªmentum four-vector (due to matter plus field) is found to be zero. These results support the viewpoints of Banerjee-Sen, Xulu and Aydogdu-Saltl. Another point is that the study agrees with the previous works of Cooperstock-Israelit, Rosen, Johri et at.

25 ref

023085   Awasthi O N;Pundhir V K (Phys Dep, Regional Inst of Edu, National Council of Educational Res & Training, Shyamla Hills, Bhopal-462 013, Email: Omnarain_awasthi@yahoo.co.in) : Electron-electron interactions and the electrical resistivity of lithium at low temperatures. Pramana J Phys 2007, 68(1), 67-74.

The electron-electron interactions in lithium metal have been examined keeping in view the recent developments. The contribution of the electron-electron Umklapp scattering processes in the electrical resistivity of lithium at low temperatures has been evaluated using a simplified spherical Fermi surface model with isotropic transition probability. The values of the electrical resistivity so obtained compare fairly well with the experimental results for lithium.

1 illus, 1 table, 27 ref

023084   Ansari A;Sharma P;Jakhar U R;Yadav H L (NO, Inst of Phys, Bhubaneswar-751 005, Email: ansari@iopb.res.in) : Shape evolution in <. Pramana J Phys 2007, 68(1), 105-10.

A two-dimensional tilted axis cranking Hartree-Fock-Bogoliubov (CHFB) calculation is performed for ⁷⁶Kr and ⁷⁸Kr nuclei up to high spins J = 30 employing a pairing-plus-quadrupole (PPQ) model interaction Hamiltonian. Intricate details of the evolution of single particle structures and shapes as a function of spin have been invesªtigated. The results show the existence of energy levels with high K quantum numbers lying close to the yrast line in both the nuclei. Such high K states should exhibit isomeric characteristics due to the K -selection rules for the γ-decays. Moreover, in ⁷⁸Kr a new band with J = 20-30 lying below the observed ground band is predicted.

2 illus, 1 table, 6 ref

022135   Yadav B S;Saran R (Molecular Spectroscopy and Biophysics Lab, D.N. (PG) College, Meerut-250 002) : Molecular polarizability and vibrational spectra of 2, 6 - dihydroxypyridine hydrochloride. Res J Chem Envir 2007, 11(1), 27-30.

Molecular polarizability of 2, 6-dihydroxy pyridine hydrochloride has been calculated by using Lippincott and Stutman model. Raman and IR spectra have been recorded in the regions 30-3750 cm^-1 and 400-4000 cm^-1 respectively. The observed bands have been explained on the basis of similar molecules reported earlier.

3 illus, 3 tables, 16 ref

022134   Upadhyay S (Physics Dep, Bhavnagar Univ, Bhavnagar-364 002) : Simple technique to measure volume of solid body using ferrofluid. Phys Educ 2006, 23(1), 21-6.

Magnetic fluid is used to measure volume of non magnetic body of random shape. Technique used in this work is based on the detection of change in the inductance of the coil (with ferrofluid as core) when body is immersed. Inductance is related to the volume of the body. Constructive details of apparatus, characteristic of magnetic fluid, theoretical and experimental data are given in this paper.

3 illus, 10 ref

022133   Sunil ;Anupama ;Divya ;Sharma R C (Applied Sciences Dep, National Institute of Technology (Deemed Univ), Hamirpur-177 005) : Effect of magnetic field dependent viscosity on thermosolutal convection in rotating ferromagnetic fluid. Proc Natn Acad Sci India-Sect A 2006, 76(Pt 4), 349-59.

Deals with the linear stability analysis of a rotating ferromagnetic fluid heated and soluted from below in the presence of uniform vertical "magnetic field. The effect of magnetic field dependent (MFD) viscosity is also incorporated in the analysis for a fluid layer contained between two free boundaries which are constrained flat, an exact solution is obtained. For the case of stationary convection, rotation, stable solute gradient and MFD viscosity always have a stabilizing effect on the onset of instability. The non-buoyancy magnetization may have a destabilizing or a stabilizing effect in the presence of MFD viscosity, whereas non-buoyancy magnetization always has a destabilizing effect in the absence of MFD viscosity. The critical wave number and critical magnetic thermal Rayleigh number for the onset of instability are also determined numerically for sufficiently large values of magnetic parameter M₁ and the results are depicted graphically. The principle of exchange of stabilities is found to hold true for the ferromagnetic fluid heated from below in the absence of stable solute gradient and rotation. The oscillatory modes are introduced due to the presence of the stable solute gradient and rotation, which were non-existent in their absence. The sufficient conditions for the non-existence of overstability are also obtained.

2 tables, 2 illus, 21 ref

022132   Sharma M;Kumar P (Protein Science and Engineering Unit, Institute of Microbial Technology, Sector 39A, Chandigarh-160 036, Email: mondyn@gmail.com) : Chemical oscillations. Resonance 2006, 11(7), 61-9.

The law of mass-action led chemists to the belief that reactions approach equilibrium steadily. So the discovery of chemical oscillations came as a surprise. Now chemists are very familiar with reactions that oscillate in time and/or space. Experimental and theoretical studies of such reactions showing temporal and spatial oscillations attract the interest of many laboratories world-wide. The Lotka-Volterra model is the simplest mathematical model which exhibits such oscillations. Uses this model to illustrate chemical oscillations with the help of a computer program.

4 illus, 4 ref

022131   Sharma J P (NO, , 68, Triveni Nagar, Naini, Allahabad-211 009) : Thermodynamic equilibrium of star cluster embedded in an isothermal configuration. Proc Natn Acad Sci India-Sect A 2006, 76(Pt 4), 305-7.

An unified approach has been made to study the thermodynamic equilibrium of a model of star clusters confined to a finite volume in a box. The system corresponds to an isothermal distribution of N-particles (plane-symmetric m = 0, cylindrical m = 1 and spherical m = 2). Some important physical parameters of the clusters have been numerically evaluated.

2 tables, 1 illus, 17 ref

022130   Sahoo S;Sahoo S (Physics Dep, National Institute of Technology, Durgapur-713 209, Email: sukadevsahoo@yahoo com) : Production and applications of radioisotope. Phys Educ 2006, 23(1), 5-11.

Over the last century, nuclear science and technology have contributed immensely to almost every social and economical sector and in virtually every corner of globe. Radioisotope is on of the tools for studying nuclear science. The radioisotopes have numerous applications in medicine, agriculture, industry and pure research. Production and some applications of radioisotopes are discussed briefly.

2 tables, 8 ref

022129   Roychoudhuri S K;Dutta P S (Mathematics Dep, Burdwan Univ, West Bengal-713 104) : Magneto-elastic interaction ina perfectly electrically conducting infinite solid with distributed time dependent heat source in thermoelasticity of type II (G-N model). Proc Natn Acad Sci India-Sect A 2006, 76(Pt 4), 331-8.

A new theory of thermoelasticity without energy dissipation is employed to study the disturbances in a perfectly electrically conducting infinite solid containing time-dependent distributed heat sources and permeated by a primary uniform external magnetic field. Analytical expressions for deformation, temperature, perturbed magnetic field and stresses are derived by the use of Laplace transform on time and then Fourier transform on space. It is found that the interactions consist of the modified elastic dilatational wave and the modified thermal wave traveling with finite speeds. The exact discontinuities of the various fields are studied at the wave fronts and compared with previous results derived by using classical coupled thermoclasticity theories. Numerical results for a copper like material are presented.

1 table, 2 illus, 21 ref

022128   Panigrahi P K (Physical Research Laboratory, , Navrangpura Ahmedabad-380 009, Email: prasanta@prl res in) : Problems from elementary quantum mechanics. Phys Educ 2006, 23(1), 61-5.

ref

022127   Navathe C P;Nigam S (Laser Plasma Div, Raja Ramanna Centre for Advanced Technology, , Indore, India-452 013, Email: cpn@cat ernet in) : Numerical evaluation of different methods used for charging capacitor bank in pulsed power application. Phys Educ 2006, 23(1), 31-46.

In pulsed power applications like solid-state pulsed lasers, the energy is first stored in large capacitor banks that are charged using different types of power supplies. It is necessary to know various parameters like charging time and efficiency of such schemes for the design and selection of components. Although it is possible to write analytical equations for these circuits, the solutions are too cumbersome due to the presence of rectifying diodes, which control the direction and flow of current depending on their bias. They can be solved more easily using numerical methods and with the use of digital computers. In this paper, author have considered charging of capacitor banks by limiting the primary current with resistor, capacitor and inductor, charging by voltage doubler and by constant current technique. In each case, the equation governing the charging process is derived, algorithm suitable for computer solution is given and numerical data is demonstrated for various values of components. This analysis will be extremely useful for getting understanding of charging process involved in various configurations of power supplies during the design of capacitor banks for energy storage.

8 tables, 13 illus, 5 ref

022126   Mahadevan S;Uma Maheswari A;Prema P;Shastry C S (Physics Dep, Amrita Vishwa Vidyapeetham, Coimbatore-641 105) : Quantum mechanical transmission with absorption. Phys Educ 2006, 23(1), 13-20.

Transmission and reflection across a rectangular barrier at energies below and above barrier is the most commonly studied topic in non-relativistic quantum mechanics. However the subtle inter-relationship ' between the barrier problem and the corresponding well problem is not widely known, in particular when absorption is present . It is shown that when a particle traverses an absorptive medium, at any given energy the absorption peaks for a particular value of absorption potential strength W₀. Similarly author studies the corresponding cases when incident energy E is increased keeping W₀ constant. Further, shows that for a given E when W₀. is made very large aborption gradually decreases and reflection overtakes it and tends towards unity. Case of transmission across a potential barrier has also been studied and well and interpret physically the behavior of absorption, transmission and reflection.

6 illus, 5 ref

022125   Kenhere D G (Physics Dep, Centre for Modeling and Simulation , University of Pune, Pune-411 007) : Bound state of one dimensional potential by numerov method. Phys Educ 2006, 23(1), 55-60.

3 illus, ref

022124   Kar G;Kunkri S;Choudhary S K (NO, , ) : Special relativity, causality and quantum mechanics - 1. Resonance 2007, 11(8), 41-52.

7 ref

022123   Kar G;Kunkri S;Choudhary S K (Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata-700 108, Email: gkar@isical.ac.in) : Special relativity, causality and quantum mechanics - 2. Resonance 2006, 11(9), 43-54.

Discusses the aspects of non-locality and non-separability of states of composite quantum systems. The probabilistic nature of quantum mechanical predictions, and the impossibility of cloning, are shown to safeguard causality in the quantum world. An example of a game which can be won exploiting quantum entanglement, but which can never be won classically, is described.

5 ref

022122   Chaturvedi S;Simon R;Mukunda N (School of Physics, University of Hyderabad, Hyderabad-500 046, Email: scsp@uohyd.ernet.in) : Space, time and relativity. Resonance 2006, 11(7), 14-29.

1 illus, 7 ref

022121   Chakraborti A (Physics Dep, BHU, Varanasi-221 005) : Econophysics: a brief introduction to modeling wealth distribution. Sci Cult 2007, 73(3-4), 55-61.

Discusses a few studies of wealth distributions in "Econophysics", the developing interdisciplinary field, culminating ideas from Economics and Physics. The topic discussed here should illustrate how simple tools and methods in physics can be applied to study economic problems.

5 illus, 31 ref

022120   Benka S G (NO, , ) : Entangled dance of physics. Sci Cult 2007, 73(3-4), 88-92.

3 illus, 3 ref

022119   Bapat M N (NO, Regional Institute of Education, Mysore-570 006, Email: mnbapat@gmail com) : On the centre of percussion. Phys Educ 2006, 23(1), 27-30.

The compound pendulum is very frequently used to study harmonic oscillations and to determine the value of 'g' in the laboratory. This article suggests what additional reaction appears at the axis of rotation if the pendulum is not released gently from its displaced angular position.

2 illus, 7 ref