004285   Zhou P;Ding R (Center of System Theory and its Applications, Chongqing Posts and Telecommunications Univ, Chongqing-400 065, China, Email: zhouping@cqupt.edu.cn) : Adaptive function projective synchronization between different fractional-order chaotic systems. Indian J Phys 2012, 86(6), 497-501.

Adaptive function projective synchronization scheme between two entirely different fractional-order chaotic systems with uncertain parameters has been addressed. The adaptive controller has been designed, and the parameter update law is also gained. One example has been presented to demonstrate the effectiveness of the proposed method.

29 ref

004284   Thander A;Mallik B (Spectroscopy Dep, Indian Association for the Cultivation of Science, 2A & 2B, Raja S.C. Mullick Road, Jadavpur, Email: spbm@iacs.res.in) : Spectroscopic studies on the photoinduced changes in some ferrocene derivatives in halocarbon solvents. Indian J Phys 2012, 86(6), 521-8.

The photoinduced changes in some ferrocene derivatives in halocarbon solvents chloroform and carbon tetrachloride (using deoxygenated solutions) have been investigated under different experimental conditions by monitoring the photoinduced changes in the electronic absorption spectra of the ferrocene derivatives in the halocarbon solvents. The spectra were recorded before as well as after photoexcitation of the sample solution by a monochromatic radiation. The results have indicated the photoinduced-charge transfer between a particular ferrocene derivative and the halocarbon solvent used. For different values of photoexcitation time (duration), absorption spectra of some of the ferrocene derivatives in halocarbon solvents have shown isobestic points. The primary step in the photo process is expected to be the dissociation of the charge transfer state to give the different ions.

6 illus, 3 tables, 35 ref

004283   Sharma N;Mahajan A (Physics Dep, Guru Nanak Dev Univ, Amritsar, Email: navdeep2512@yahoo.co.in) : Zero-g games for space habitats. Res Rev : J Space Sci Technol 2013, 2(1), 21-5.

Dream of mankind to establish a permanent residence in space is yet to take wings of accomplishment. We, are not too sure about the human body's long term adherence to tough and challenging conditions of space. Also, the inability of various governments/ private agencies to generate finances for developing long term self sustainable biospheres in space has further curtailed these wings. To overcome these hurdles we have designed zero g games for proposed space Olympics. In the paper, details of a few thrilling games have been discussed to encourage physicists to work in this promising area.

4 illus, 16 ref

004282   Samanta R;Jana S;Ghosh S;Purkait M;Mandal C R (Physics Dep, Ramakrishna Mission Residential College, Narendrapur, Kolkata-700 103, Email: mpurkait_2007@rediffmail.com) : Electron capture cross section in collision of multi-charged neon ions with ground state Hydrogen and Helium. Indian J Phys 2012, 86(6), 503-12.

The classical trajectory Monte Carlo method and the post form of three-body boundary corrected continuum intermediate state (BCCIS-3B) approximation are employed to calculate the cross sections for total and state-selective electron capture in collision of highly charged Ne^q+ ions with ground state hydrogen atom in the intermediate to high energy region. In both these methods, the active electron interactions with the partially stripped neon ions are described by a model potential containing both a long-range part and a short-range part. Also calculated the double electron-capture cross sections in collision of fully stripped neon ion with helium atom in the energy range 80-2,000 keV/amu using the post-form of four-body BCCIS approximation (BCCIS-4B). In BCCIS formalism, the intermediate continuum state of the active electrons with the projectile ion has been taken into account as the projectile charge is greater than the target charge. In addition, state-selective charge transfer cross sections are given in tabular and graphical form.

10 illus, 2 tables, 36 ref

004281   Ramegowda M (Post Graduate Physics Dep, Government College, Mandya-571 401, Email: hmrgowda@yahoo.com) : Theoretical study of the absorption spectra of triamterene. Int J pharm Sci Res 2013, 4(3), 1192-5.

Time dependent density functional theory (TDDFT) calculations have been carried out to study the electronic structure and the UV absorption spectra of Triamterene. The UV spectra have been investigated with inclusion of solvent effect. The B3LYP functional with a 6-31G(d, p) basis sets have been used to compute absorption energies. The solvent effects have been described within the polarizable continuum model (PCM). The geometries are optimized using density functional theory (DFT) with B3LYP functional combined with 6-31G(d, p) basis sets. The vertical absorption energies both in gas phase and in polar solvents such as ethanol, methanol and water were computed. Red-shift of the absorption maximum in the polar solvents is discussed in terms of electrostatic interaction energy, oscillator strength and dipole moment.

3 illus, 1 table, 30 ref

004280   Paul S N;Das C;Paul I;Bandyopadhyay B; Chattopadhyaya S;De S S (NO, Swami Vivekananda Institute of Science and Technology, Dakshin Gobindapur, P.S.-Sonarpur, Kolkata-700 145, Email: drsnpaul@gmail.com) : Ion acoustic solitary waves in an electron-ion-positron plasma. Indian J Phys 2012, 86(6), 545-53.

Large amplitude ion-acoustic solitary waves have been theoretically studied in a non-collisional plasma consisting of warm positive ions, positrons and isothermal electrons using pseudo-potential (effective potential) method. The expressions of phase velocities of slow- and fast- modes of the wave have been derived and graphically analyzed. The critical values of densities of the positrons and the ions, Mach number and positron temperature for the excitation of ion-acoustic solitary wave have also been obtained. The solutions of the first-order and next higher order solitary waves have been obtained and the profiles of the solitary waves have been drawn taking different values of the plasma parameters. It has been observed that both compressive and rarefactive solitary waves are being excited in presence of positrons in the plasma. The variation of amplitudes of the solitary waves has been shown graphically for different values of density and temperature of positrons, drift velocity and temperature of the ions.

5 illus, 50 ref

004279   Paul S N;Bhattacharya S K;Paul B;Ghosh B (NO, Swami Vivekananda Institute of Science and Technology, Dakshin Gobindapur, P.S.-Sonarpur, Kolkata-700 145, Email: bsdvghosh@gmail.com) : Nonlinear faraday rotation in ion-cyclotron Whistler waves in the ionosphere. Indian J Phys 2012, 86(6), 489-92.

Theoretical investigations are made on the nonlinear Faraday rotation of obliquely propagating ion-cyclotron whistler waves in presence of negative ions in the ionosphere. Numerical estimation shows that the negative ions and the propagation angle have appreciable effects on the nonlinear Faraday rotation of the whistler in the ionosphere.

3 illus, 22 ref

004278   Patel S;Varma P;Tiwari M S (Physics Dep, Dr. H.S. Gour Central Univ, Sagar, Madhya Pradesh-470 003, Email: poornimavarma@yahoo.com) : Effect of parallel electric field on electromagnetic ion-cyclotron waves with hot anisotropic plasma. Indian J Phys 2012, 86(6), 535-43.

The effect of parallel electric field on the growth rate, parallel and perpendicular resonant energy of the electromagnetic ion-cyclotron (EMIC) waves with general loss-cone distribution function in hot anisotropic plasma in auroral acceleration region is investigated by particle aspect approach. The ion beam driven by parallel electric field is included in the analysis whereas electrons are assumed mixed with the back ground plasma. Plasma consisting of resonant and non-resonant particles has been considered. It is assumed that the resonant particle and ion beam participate in energy exchange with the wave, whereas non-resonant particles support the oscillatory motion of the wave. We observed that the parallel electric field is to control the growth rate of the EMIC wave, whereas the effect of steep loss-cone distribution is to enhance the growth rate and perpendicular heating of the ions. This study is relevant to analyse the broad scenario of EMIC waves in the auroral acceleration region of the earth's magnetoplasma.

12 illus, 53 ref

004277   Onah C L;Arinzechukwu K C;Elekwachi F I (Physics Dep, Dederal Technology Univ, Owerri, Nigeria, Email: cossyonah@gmail.com) : Designing, constructing and testing a 90 cm parabolic satellite dish using fiberglass material. Res Rev : J Space Sci Technol 2013, 2(2), 12-26.

In this paper, authers designed and constructed a parabolic satellite dish using fiberglass material for K_u-band reception that would be able to receive stations from any transponder focused on it which may be coded or non-coded stations. To achieve this objective, a parabolic graph was plotted using the geometry calculations of a parabola (i.e., the axis of asymmetry against its directrix). From this calculation and graph, the form-work was obtained which helped in the construction of the mold. The materials used for constructing this satellite antenna were sourced locally and these materials include fiber mats, resin, accelerator, catalyst, calcium carbonate (CaCO³), polish/wax, etc. These materials and chemicals for the production of a fiberglass dish were mixed in proper proportion, and the mixture was used in soaking the fiber mat material placed in layer of two on the mold. This gave a parabolic dish when removed from the mold, which was smoothened and an aluminum foil was placed on it with an adhesive for proper reflection of signals to the focus. The dish was assembled with its accessories and installed in an area free from obstructions such as buildings and trees, and the LNBF was connected to the receiver which was connected to the television through an audio-video cable. A particular transponder was selected due East and was tracked, which gave a signal strength fluctuating between the range of 70-82% with its quality at 90%.

4 illus, 1 table, 25 ref

004276   Onah C I;Iloka C M (Physics Dep, Federal Technology Univ, Owerri, Nigeria, Email: cossyonah@gmail.com) : Construction of an ultrasonic pest repeller. Res Rev : J Space Sci Technol 2013, 2(1), 1-15.

Ultrasonic pest repeller (DPR) was constructed to repel pest like rodent from home in order to prevent damage and possible infections or diseases caused by rodents. Rodents can perceive ultrasonic sound of frequencies within the range of 20 to 65 kHz. Our UPR when tested emit varying ultrasonic frequencies approximately within the range of 20 to 50 kHz. We found that these varying frequencies are like sound produced by Jackhammer and causes auditory stress to rodents and discourages them from habituating within the environment where this sound is effective. Ultrasonic frequencies are frequencies above 20 kHz. This work was simulated with electronics simulator software called PROTEUS to study and ensure its operating characteristics before construction. This device is more humane and sanitary to use in home as they do not involve traps and poisons which are harmful to man. Also, the varying ultrasonic frequencies emitted are inaudible to man.

17 illus, 24 ref

004275   Li D C;Fang L;Deng S K;Kang K Y;Wei W H;Ruan H B (Applied Physics Dep, Chongqing Univ, Chongqing-400 044, People's Republic of China, Email: fangliangcqu@yahoo.com.cn) : Structural and electronic properties of type-I clathrates Ba₈Cu_xGa_16-xSn₃₀ from first-principle calculations. Indian J Phys 2012, 86(6), 447-53.

The effects of Cu-doping concentration on the structural and electronic properties of Ba₈Cu_xGa_16-x30 (0 ≤ x ≤ 3) type-I clathrate compounds have been investigated by first-principle calculations. Starting with the stable structures of the type-I clathrate semiconductors Ba₈Ga₁₆Sn₃₀ containing no Ga-Ga bonds, we have constructed unit cells of Ba₈Cu_xGa_16-xSn₃₀. The dependence of the structural and electronic properties of these compounds with x is discussed. The results reveal that the interaction between the rattler atom and the cage is affected by Cu doping, which suggests that Cu doping may play a role on the thermal conductivity. It is shown that the Ba₈Ga₁₆Sn₃₀ is an intrinsic semiconductor, but Cu doping leads to p-type transport characteristics. Detailed analysis of the electronic structures for Cu-doped clathrates imply that Cu 3d electrons may display both itinerant and localized features and the electronic states near the top of the valence band are modified by the Cu 3d states. The number of states near the Fermi level is increased by the coupling of sp-d, which may lead to reduced stability of the structure.

5 illus, 4 tables, 42 ref

004274   Khordad R (Physics Dep, College of Sciences Yasouj Univ, 75914-353 Yasouj, Iran, Email: khordad@mail.yu.ac.ir) : Effect of position-dependent effective mass on linear and nonlinear optical properties in a quantum dot. Indian J Phys 2012, 86(6), 513-9.

In this paper, the effect of constant effective mass and position-dependent effective mass on the optical properties of a spherical quantum dot has been studied. For this purpose, the intersubband optical absorption coefficient and the refractive index changes are obtained using both a constant effective mass and position-dependent effective mass. According to the results obtained from the present work, it was shown that spatially varying electron effective mass plays an important role in obtaining the intersubband optical absorption coefficients and refractive index changes in the finite and infinite quantum dots.

4 illus, 37 ref

004273   Gupta M R;Banerjee R;Mandal L K;Bhar R;Pant H C;Khan M;Srivastava M K (Instrumentation Science and Centre for Plasma Studies Dep, Jadavpur Univ, Kolkata-700 032, Email: mkhan_ju@yahoo.com) : Effect of viscosity and surface tension on the growth of Rayleigh-Taylor instability and Richtmyer-Meshkov instability induced two fluid interfacial nonlinear structure. Indian J Phys 2012, 86(6), 471-9.

The effect of viscous drag and surface tension on the nonlinear two fluid interfacial structures induced by Rayleigh-Taylor instability and Richtmyer-Meshkov instability have been investigated. Viscosity and surface tension play important roles on the fluid instabilities. It is seen that the magnitude of the suppression of the terminal growth rate of the tip of the bubble height depends only on the viscous coefficient of the upper (denser) fluid through which the bubble rises. However, in regard to spike it is shown that in an inviscid fluid spike does not remain terminal but approaches a free fall <126> 1/2 γgt² (γ is of oder unity) as the Atwood number A increases. In this respect there exits qualitative agreement with simulation result and also with some earlier theoretical results. Viscosity reduces the free fall velocity appreciably and with increasing viscosity tends to make it terminal. Results obtained from numerical integration of the relevant nonlinear equations describing the temporal development of the spike support the foregoing observations.

9 illus, 29 ref

004272   Ghosh S;Choudhury A;Sarma J K (Physics Dep, Tezpur Univ, Tezpur-784 028, Email: gsovan@gmail.com) : Radii of electrons and their α-quantized relations. Indian J Phys 2012, 86(6), 481-3.

Varieties of experimental and theoretical considerations indicate eight different types of radii of an electron like classical electron radius, Compton radius (electron), electromagnetic radius (electron) etc. Also discuss the α-quantized relations among different types of radii of electrons, where a is the fine structure constant. In addition, α-quantized results for current and magnetic fields are also focused here.

10 illus, 2 tables

004271   Falayi E O;Beloff N (Physics Dep, Tai Solarin Education Univ, Ijagun, P.M.B. 2118, Ijebu-Ode, Nigeria, Email: Olukayodefalayi@yahoo.com) : Modelling of geomagnetically induced currents during geomagnetic storms using geoelectric fields and auroral electrojet indices. Indian J Phys 2012, 86(6), 423-9.

The effects of space weather on ground based technology mostly occur due to the varying geomagnetic field during geomagnetic storms, producing geomagnetically induced current (GIC). Space weather storms involve intense and rapidly varying electric currents in the ionosphere, which create geoelectric and geomagnetic fields at the Earth's surface. In this study we have investigated some intense geomagnetic storms: September 18th, 2000; March 31th, 2001; October 21st, 2001; November 6th and 24th, 2001; October 29th and 31st, 2003 and November 9th, 2004. The electric field for each day has been computed using ground conductivity and geomagnetic recordings. The conductivity models are determined by least square fit between the observed and predicted GIC values. Our results show that GIC are strongly correlated with the geoelectric field, and also with eastward and westward auroral electrojet indices and time derivatives of the horizontal geomagnetic field. Root mean square error statistical test has been employed to evaluate the accuracy of the models used.

3 illus, 2 tables, 33 ref

004270   Chen T;Zhang T;Zhou J F;Zhang J W;Liu Y H; Wang G C (Teaching and Research Section of Physics, Chengdu Medical College, Chengdu610 083, People's Repulic of China, Email: chentaocmc@163.com) : Piezoelectric properties of [(K_1-xNa_x)_0.95Li_0.5]_0.985 Ca_0.015(Nb_0.95Sb_0.05)_0.985Ti_{0.0 15}O₃ lead-free ceramics. Indian J Phys 2012, 86(6), 443-6.

In this paper, we have investigated the effect of K/Na ratio on the electrical properties of Li_0.05]_o.985Ca_0.015(Nb_0.95Sb_0.05)_{0.98 5}Ti_0.015O₃ (K_1-xNa_xLCNST) lead-free piezoelectric ceramics prepared by the conventional solid-state method. A pure phase is observed in these ceramics with x = 0.30-0.80, and the K/Na ratio results in the phase transition of K_1-xNa^LCNST ceramics. The Curie temperature of K_1-xNa_xLCNST ceramics decreases with the increase of Na content. A higher dielectric constant is observed in the ceramic with x = 0.40, and the dielectric loss almost decreases with the increase of Na content. Moreover, an enhanced piezoelectric behavior (d <126> 227 pC/N and k_p <126> 45.3%) has been demonstrated in the K_1-xNa_xLCNST ceramic with x = 0.40. Therefore, optimizing the K/Na ratio is an effective way to enhance the piezoelectric properties of K_1-xNa_xLCNST ceramics.

4 illus, 23 ref

004269   Chatterjee P;Das B;Wong C S (Plasma Research Laboratory Physics Dep, Malaya Univ, 50603 Kuala Lumpur, Malaysia, Email: prasantachatterjee1@rediffmail.com) : Dust acoustic solitary waves in a dusty plasma with variable dust charge and an arbitrary streaming ion beam. Indian J Phys 2012, 86(6), 529-33.

Conditions for the existence of dust acoustic solitary waves have been investigated on the nonlinear, unmagnetized homogeneous dusty plasma with variable dust charge and an arbitrary streaming ion beam. The Sagdeev's pseudopotential has been derived in terms of u_d, the dust fluid flow velocity. It is found that there exists a critical value of u_d0(^0), the value of u_d at which (u_d)² = 0, beyond which the solitary waves cease to exist. This critical value of u_d depends on other parameters like dust temperature, etc.

6 illus, 31 ref

004268   Baral P C;Rout G C (Physics Dep, B.J.B. Junior College, Bhubaneswar-751 104, Odisha, Email: pbaral@iopb.res.in) : Modified BCS theory of heavy fermion superconductivity. Indian J Phys 2012, 86(6), 431-7.

In this paper author derived an expression for the superconducting gap equation for U and Ce based heavy fermion (HF) systems within a modified weak coupling theory of superconductivity. The calculated gap equation presents a mixture of pairing amplitudes of two different quasi-particle bands α and β. These two gap equations are solved numerically and self-consistently within the cut-off energy which arises due to the Kondo energy. It is found that the energy dependence of the enhanced density of states for the HF systems clearly manifests itself in the theory and the Kondo energy naturally takes the role of cut-off energy (ω_c), as long as the effective cut-off energy is large in comparison with the Kondo energy. The numerical analysis confirms this result and shows that superconducting transition temperature is independent of effective cut-off energy employed within this approach. The temperature dependence of gap equations are studied by varying the model parameters like position of ↵-level, hybridization and coupling constants of the HF systems.

5 illus, 31 ref

004267   Arivazhagan G;Mahalakshmi M;Jeenathus Zahira S A (Physics Dep, Thiagarajar College, Mdurai-625 009, Email: arivuganesh@gmail.com) : On the study of molecular interactions of alcohol-ester binary mixtures by acoustic and viscometric studies. Indian J Phys 2012, 86(6), 493-6.

The values of ultrasonic velocity, density and viscosity of the binary mixtures ethanol + butyl acrylate and ethanol + butyl methacrylate have been measured over the entire composition range at 303 K. Using these data, inter-molecular free length, isentropic compressibility, excess values of isentropic compressibility, viscosity and Gibb's free energy have been determined. The excess values have been fitted to Redlich-Kister type polynomial. Analysis of the results shows the existence of specific interaction between the mixture constituents.

4 illus, 3 tables, 34 ref

004266   Amrollahi Bioki H;Borhani Zarandi M (Physics Dep, Atomic and Molecular Groups Yazd Univ, Yazd, Iran, Email: hojjat2222@yahoo.com) : Electrical properties of organic-inorganic semiconductor heterojunction. Indian J Phys 2012, 86(6), 439-41.

Conducting polyaniline (PANI) was prepared by chemical oxidation polymerization in the presence of excess hydrochloric acid. Zinc sulfide (ZnS) thin films were deposited on glass substrates at the pressure of 10^-5 mbar by thermal resistor evaporation technique. The solution of conducting PANI has been printed on pellet of ZnS using spin-coating technique. I-V characteristics of ZnS thin film and printed conducting PANI have been recorded at room temperature. The results indicated that I-V of conducting PANI shows non-ohmic behavior and I-V characteristic of conducting PANI printed ZnS, a PANI-ZnS heterojunction, shows the rectification effect and confirms that a diode can be fabricated by using simple technique.

2 illus, 25 ref

003219   Yuhua O Y;Ping Y (NO, College of Physics and Electronic Engineering, Nortwest Normal Univers, Lanzhou 730 070, China, Email: ouyangh1104@163.com) : Audible thunder characteristic and the relation between peak frequency and lightning parameters. J Earth Syst Sci 2012, 121(1), 211-20.

In recent summers, some natural lightning optical spectra and audible thunder signals were observed. Twelve events on 15 August 2008 are selected as samples since some synchronizing information about them are obtained, such as lightning optical spectra, surface E-field changes, etc. By using digital filter and Fourier transform, thunder frequency spectra in observation location have been calculated. Then the two main propagation effects, finite amplitude propagation and attenuation by air, are calculated. Upon that taken the test thunder frequency spectra and work backward to recalculate the original frequency spectra near generation location. Thunder frequency spectra and the frequency distribution varying with distance are researched. According to the theories on plasma, the channel temperature and electron density are further calculated by transition parameters of lines in lightning optical spectra. Pressure and the average ionization degree of each discharge channel are obtained by using Saha equations, charge conservation equations and particle conservation equations. Moreover, the relationship between the peak frequency of each thunder and channel parameters of the lightning is studied.

4 illus, 2 tables, 20 ref

003218   Yousef E S;Al-Salami A E;Hotzel M (Physics Dep, Faculty of Science, King Khalid University, P.O. Box 9004, Abha, Saudi Arabia, Email: omn_yousef2000@yahoo.com) : Optical and thermal characteristics of glasses based on TeO₂. Bull Mater Sci 2012, 35(6), 961-67.

Glass samples have been synthesized in quaternary system based on TeO2-oxide within composition, 85TeO_2-5Nb₂O_5-5ZnO-5Ag₂O, 68TeO₂-5Nb₂O₅-20ZnO-7Na₂O and [(75-x)TeO₂-5Nb₂O₅-20ZnO-xPbO,_x=7,18 mol%]. Structural characterization of the glasses was studied with respect to their thermal stability, refractive indices, third order nonlinear optical susceptibility, IR spectra and Vickers hardness. For four different prepared glasses, density in the range from 5.3744 to 6.0731 g.cm^-1, the glass transition temperature (T_g) in the range from 326 to 350°C and refractive indices, n, in the range from 2.1273 to 2.2123 at 435 nm and Vickers hardness, H_v, in the range from 2.91 to 3.44 GPa were determined. The value of third order nonlinear optical susceptibilities<157>X⁽³⁾<157> <61> 17.9.10^-13 esu of glass within composition, 68TeO₂-5Nb₂O₅-20ZnO-7PbO, was measured by using degenerate four-wave mixing (DFWM).

6 illus, 3 tables, 25 ref

003217   Tripathi S K;Gupta A;Manju Kumari (Physics Dep, Jaypee University of Engineering and Technology (JUET), Raghogarh, Guna-473 226) : Studies on electrical conductivity and dielectric behaviour of PVdF-HFP-PMMA-NaI polymer blend electrolyte. Bull Mater Sci 2012, 35(6), 969-75.

Polymer blend electrolytes composed of poly(vinylidene fluoride-co-hexafluoro-propylene), poly(methyl methacrylate) and 1 0 M NaI as salt have been synthesized using solution caste technique by varying the PVdF(HFP)-PMMA blend concentration ratio systematically. A.c. impedance studies were performed to evaluate the ionic conductivity of the polymer electrolyte films. The highest ionic conductivity at room temperature for [PVdF(HFP)-PMMA(4:1)](20 wt%) - [NaI(1 0 M)](80 wt%) system is found to be 1 67x10^-2Scm^-1. XRD studies reveal complete complexation of the salt in the polymeric blend systems. The temperature dependence conductivity has been performed in the range of 303-373 K and it is observed that it obeys the Arrhenius behaviour. It has been observed that the dielectric constant, ε_r and dielectric loss, ε_i, increases with temperature in the lower frequency region and is almost negligible in the higher frequency region. This behaviour can be explained on the basis of electrode polarization effects. Plot of real part, M_r and imaginary part, M_i vs frequency indicates that the systems are predominantly ionic conductors. The phenomenon suggests a plurality of relaxation mechanism.

6 illus, 32 ref

003216   Suhail M H (Physics Dep, College of Science, University of Baghdad, Iraq, Email: mhsuhail@yahoo.com) : Structural and optical properties of Zn doped CuInS₂ thin films. Bull Mater Sci 2012, 35(6), 947-56.

Copper indium sulphide (CIS) films were deposited by spray pyrolysis onto glass substrates from aque-ous solutions of copper (II) sulphate, indium chloride and thiourea using compressed air as the carrier gas. The copper/indium molar ratio (Cu/In) in the solution 1(1:1) and the sulphur/copper ratio (S/Cu) was fixed at 4. Structural properties of these films were characterized. The effects of Zn (0-5%) molecular weight compared with CuInS2 Source and different substrate temperatures on films properties were investigated using X-ray diffraction (XRD) and optical transmission spectra. Optical characteristics of the CuInS₂ films have been analysed using spectropho-tometer in the wavelength range 300-1100 nm. The absorption spectra of the films showed that this compound is a direct bandgap material and gap values varied between 1.55 and 1.57 eV, depending on the substrate temperatures. Zn-doped samples have a bandgap energy of 1.55-1.95 eV. It was observed that there is an increase in optical bandgap with increasing Zn % molecular weight. The optical constants of the deposited films were obtained from the analysis of the experimentally recorded transmission and absorption spectral data. The refractive index, n and dielectric constants, <101F255> 1 And ε 2, were also discussed and calculated as a function of investigated wavelength range and found it dependent on Zn incorporation. We found that the Zn-doped CuInS₂ thin films exhibit P-type conductivity and we predict that Zn species can be considered as suitable candidates for use as doped acceptors to fabricate CuInS₂-based solar cells. The paper presents a study concerning the influence of deposition parameters (temperature of the substrate and concentration of Zn (1-5)% from 0.16 M ZnCl₂) on the quality of CuInS₂ thin films achieved by spray pyrolysis on glass substrate from solutions containing 0.02 M CuCl₂.2H₂O, 0.16 M thiourea and 0.08 M In₂Cl₃.5H₂O.

14 illus, 35 ref

003215   Sivakumar K;Senthil Kumar V;Kumarasamy N M; Rai M T;Senthil T S (Physics Dep, Karpagam University, Coimbatore-641 021, Email: phy_thambi@rediffmail.com) : Influence of pH on ZnO nanocrystalline thin films prepared by sol-gel dip coating method. Bull Mater Sci 2012, 35(3), 327-31.

ZnO nanocrystalline thin films have been prepared on glass substrates by sol-gel dip coating method. ZnO thin films have been coated at room temperature and at four different pH values of 4, 6, 8 and 10. The X-ray diffraction pattern showed that ZnO nanocrystalline thin films are of hexagonal structure and the grain size was found to be in the range of 25-45 nm. Scanning electron microscopic images show that the surface morphology improves with increase of pH values. TEM analysis reveals formation of ZnO nanocrystalline with an average grain size of 44 nm. The compositional analysis results show that Zn and O are present in the sample. Optical band studies show that the films are highly transparent and exhibit a direct bandgap. The bandgap has been found to lie in the range of 3.14-3.32 eV depending on pH suggesting the formation of ZnO nanocrystalline thin films.

5 illus, 15 ref

003214   Nair S K;Sijikumar S;Prijith S S (Space Physics Lab, Vikram Sarabhai Space Centre, Indian Space Research Organisation, Thiruvananthapuram-695 022, Email: sandymad@gmail.com) : Impact of continental meteorology and atmospheric circulation in the modulation of aerosol optical depth over the Arabian Sea. J Earth Syst Sci 2012, 121(2), 263-72.

Time series analysis of Aerosol Optical Depth (AOD) derived from NOAA-AVHRR data during the period 1996-1999 and the MODIS data during 2000-2009 over the Arabian Sea revealed a systematic biennial variability in the high AOD during summer months. The variability is more prominent over the northern and central parts of the Arabian Sea and became less significant towards southern latitudes. The possible mechanisms for these are examined by estimating the source strength over coastal Arabia and AOD flow rate through the western boundary of the Arabian Sea. Both these show clear signatures of biennial variability with same phase as AOD for most of the years. This result indicates that the observed biennial variability in AOD is likely to be the outcome of combined effects of biennial variability in wind generated sea-salt aerosols and dust transported from Arabia.

6 illus, 53 ref

003213   Lee H S;Bae S H;Han C H;Sekhon S S (Physics Dep, Guru Nanak Dev University, Amritsar-143 005, Email: sekhon_apd@yahoo.com) : Efficiency enhancement of dye-sensitized solar cells with addition of additives (single/binary) to ionic liquid electrolyte. Bull Mater Sci 2012, 35(6), 1003-10.

The effect of addition of single and binary additives on the performance of dye-sensitized TiO2solar cells based on electrolytes containing an ionic liquid (IL), 1,2-dimethyl-3-propylimidazolium iodide (DMPII) has been studied. Among the seven additives used, the addition of 2-(dimethylamino)-pyridine (DMAP) to IL resulted in best cell efficiency, which showed further enhancement with the addition of 5-chloro-1-ethyl-2-methylimidazole (CEMI) as second additive. The efficiency of the dye-sensitized solar cell (DSC) based on an electrolyte containing binary additives (DMAP and CEMI in equal molar ratios) has been found to increase by 62.5% from 4.35 to 7.07%. The dependence of different photovoltaic performance parameters (V_oc,J_sc,ff,χ) of DSC upon temperature has beenstudied over a 30-120°C range and only a small decrease in conversion efficiency has been observed. The electrolyte containing binary additives (DMAP and CEMI) shows best cell performance up to 120°C.

7 illus, 24 ref

003212   Khan Z;Pradhan S;Ahmad I (NO, Institute for Plasma Research, Gandhinagar-382 428, Email: ziauddin@ipr.res.in) : Heat conduction and thermal stabilization in YBCO tape. Bull Mater Sci 2012, 35(3), 449-51.

Yttrium barium copper oxide (YBCO) coated conductors are widely used in the conduction-cooled superconducting magnets with rapid development in refrigeration technologies at present. `Quench' is a state that refers to the irreversible and uncontrolled superconductor to resistive transitions in the superconductor. The propagation of `quench' or `normal zone' has different characteristics in these high temperature superconductors (HTS) compared to low temperature superconductors. The superconductor to normal index, known as `n' is much flatter in HTS. The hot spot emerging in local region due to quench and non-uniform critical current may cause permanent damage to whole HTS tape and hence the magnet winding pack. Thus it is necessary to determine the temperature profile along the length of HTS tape under a given energy (joule heating) such that propagation of the hot spot developed locally can be prevented early. In this study, a one dimensional, time dependent heat diffusion equation with appropriate boundary conditions are used to describe the consequences of the normal zone propagation resulting in the temperature diffusion in a HTS tape. The results demonstrate the necessity of adequate cooling of the edges of the flat HTS tapes to prevent irreversible normal zone transitions.

4 illus, 9 ref

003211   Haghighi B;Bozorgmehr M R (Thermophysical Properties Research Laboratory, Chemistry Dep, Faculty, Birjand University, 97175-615, Birjand, Iran, Email: haghighi.behzad@gmail ) : Joule-thomson inversion curves calculation by using equation of state. Asian J Chem 2012, 24(2), 533-7.

Since the prediction of the Joule-Thomson inversion curve is known as a sever test of the equations of state (EoS). Some cubic equations of state (CEoS) can eventually have inadequate prediction for checking their ability to calculate the Joule-Thomson inversion curve. In this paper the Joule-Thomson inversion curve has been used to test the predictive capabilities of some recent equations of state. This enables us to judge the accuracy of the results obtained from different equations of state. These five equations of state are: Wang-Gmehling (WG) equations of state, modified Peng-Robinson by Twu-Coon-Cunningham (PR-TCC) equations of state, Riazi- Mansoori (RM) equations of state, Geana equations of state and modified Peng-Robinson-Stryjek- Vera proposed by Samir I. Abu-Eishah (PRSV2) equations of state. All of these equations of state are modified van der Waals (vdW) equations of state recommended in the literature for estimating volumetric properties of relevant compounds. As a corollary to the present study, we have perceived that the investigated equations of state give good prediction of the low-temperature branch of the inversion curve, except for Riazi-Mansoori and Geana equations of state. We also calculated maximum inversion temperature and maximum inversion pressure for every component used in this work.

5 illus, 1 table, 48 ref

003210   El-kashlan H M;Ahmed A M (Physics and Chemistry Dep, Faculty of Education, Alexandria University, Alexandria, Egypt, Email: helkashlan@hotmail.com) : Effect of angle of rotation on the rate of electropolishing. Asian J Chem 2011, 23(4), 1523-6.

Effect of angle of inclination on the rate of mass transfer was studied by measuring the limiting current of polishing of copper in phosphoric acid using parallel plate cell. Different factors were studied as phosphoric acid concentration, different angles of inclination and temperatures. Five concentrations of phosphoric acid were used, namely, 6, 8, 10, 12 and 14 M. Temperature was 23 ± 1 °C. Different angle of rotations were used as 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135°, 150°. The limiting current was found to increases by increasing angle of rotation in divided and undivided cell and limiting current decreases by increasing H₃PO₄ concentration. A comparison between the limiting current measured in divided and undivided cells shows that in undivided cells cathodic H₂ evolution increases the anodic limiting current by an amount ranging from 4.8 to 42 % depending on acid concentration and angle of inclination.

7 illus, 2 tables, 15 ref

003209   David T W (Physics Dep, Olabisi Onabanjo University, PMB 2002, Ago-Iwoye, Nigeria, Email: wemidavid@yahoo.com) : Investigation into quiet and magnetic storms periods above Magadan during October - December 2003. Indian J Radio Space Phys 2013, 42(2), 89-96.

Investigated the ionospheric response of the latitude above Magadan to the geomagnetic storms during October - December 2003. The study was based on storm time disturbance index, Dst, and the corresponding foF2 data above the ionosphere of Magadan in the East Asian sector. The response was investigated at all classes of storm and the quiet period inclusive. The analysis of the foF2 data during October - December 2003 shows that Dst of low magnitude can cause intense ionospheric storm. Dst values <62> -30 nT, which has been generally accepted to be quiet period caused major ionospheric storms of the order of 65% depletion and 59% enhancement in October. Also, two weeks before the commencement of the very intense geomagnetic storm on 20 November 2003 (Dst <60> -422 nT), quiet period (Dst <62> -30 nT) caused major ionospheric storms of the order of 70% enhancement and 45% depletion. December that was predominantly quiet, the weak Dst produced intense ionospheric storms of the order of 76% enhancement and 70% depletion. It is worthy to note that the peak positive Dst on 20 December 2003 between 06:00 and 09:00 hrs UT caused an intense ionospheric depletion above the ionosphere of Magadan with a peak value of <126>70%.

6 illus, 3 tables, 22 ref

003208   Bhujbal P M;Dhoble S J (Physics Dep, R.T.M. Nagpur University, Nagpur-440 010, Email: sjdhoble@rediffmail.com) : Lyoluminescence in Ce<. Bull Mater Sci 2012, 35(3), 453-7.

Lyoluminescence (LL) in γ -ray irradiated (KNa)Br : Ce³⁺ phosphors are reported in this paper. LL of (KNa)Br : Ce³⁺ have been recorded for different γ -ray doses. The nature of variations of LL peak intensities is found to be linear with γ -ray irradiation dose and LL peak intensity is found to be dependent on concentrations (0.1-10 mol%) of added Ce³⁺ ions in the (KNa)Br host lattice. Negligible fading in the prepared sample is observed.

2 illus, 29 ref

002255   Vijayan K;Pillai R M;Thomas P C (Precision Instruments Laboratory, ISRO Inertial Systems Unit, Thiruvananthapuram) : Measurement of microstructure for sensor applications. Mfg Technol Today 2012, 11(6), 15-17.

Micro structures are the vital elements used in many types sensors coming in the micro and nano engineering regime. A typical pendulous accelerometer used for the measurements of acceleration consists of a pair of micro hinge with a thickness of 0.015mm which works as a low stiffness spring in the assembly. The hinge support a proof mass through a pendulum and when the assembly experience acceleration, the suspended mass change its position by deflecting the hinge to the direction depends upon the direction of input. Both hinge need to be coplanar and to be in uniform size to ensure a perfect highly sensitive sensor assembly with sufficient reliability. In this paper a measurement procedure is detailed with specific set up including the measuring device, fixtures etc. to confirm the functional requirements of the assembly and thereby the sensor performance.

5 illus, 1 ref

002254   Tiwari R K (Physics & Electronics Dep, D R M L Avadh University, Faizabad-224 001, Email: rktiwari2323@yahoo.co.in) : Theoretical approach towards more generalized tunneling model. Bull pure appl Sci-Sect D 2012, 31(2), 219-23.

Various tunneling models play very convenient role in understanding the extra ordinary properties exhibited by the impurity added crystals. Keeping it in view in present investigation a more complicated <60>n10<62> tunneling model has been developed having O_h symmetry . Author worked out possible degeneracies and corresponding wave functions for generalized <60>n10<62> tunneling model.

1 illus, 19 ref

002253   Sharma S V (NO, Regional Institute of Education, NCERT, Ajmer-305 004, Email: svsriea@yahoo.co.in) : Structural studies of carbon soot films. Bull pure appl Sci-Sect D 2012, 31(2), 167-72.

The results of structural (SEM, TEM, ED and XRD) studies of carbon soot films synthesized by graphite are welding technique have depicted that these films are comprising of an assembly of micro-crystalline clusters of different sizes along with amorphous carbon dust. It is worthwhile to mention over here that the sizes and their concentration of micro-crystalline clusters are influenced by the film growth conditions. SEM, TEM, ED and XRD studies have shown that micro-crystalline clusters are having hexagonal symmetry.

3 illus, 2 tables, 27 ref

002252   Sharma R;Usha Kiran;Ojha V N;Anil Kumar (NO, National Physical Laboratory (CSIR), New Delhi-110 012, Email: rina@nplindia.org) : Investigations into roughness of mass standards at NPL-I. Mfg Technol Today 2012, 11(6), 25-6.

Surface quality of mass standards is an important parameter. Surface roughness of mass standards is important as it is known to be related to contamination with pollutants (such as adsorbed water vapors etc.) and the stability of mass standards. There is a growing interest in surface roughness measurement among mass metrologist. In the present paper we present the work carried out to investigate the roughness of mass standards and try to correlate it with stability of mass standards.

1 illus, 1 table, 5 ref

002251   Sharma A;Aparajita;Kumari R;Shekhar S (Physics Dep, R D S College, Muzaffarpur, Bihar) : Electronic quantum transport through nanowires with one sided surface roughness in the presence of a perpendicular magnetic field. Bull pure appl Sci-Sect D 2012, 31(2), 215-18.

Studied the behaviour of higher transverse modes. Author gave for each of these modes remarkably accurate analytical estimate for its specific localization length. All modes in the regular island were effectly coupled to one another by dynamical tunneling in the presence of irregular yet directed motion because of interplay between directed regular motion and counter moving irregular motion, which gave rise to characteristic structures in the mode-specific transmission probabilities of the current-transporting regular modes. These intricate .structures can be accounted for by a simple magnetic field, applied perpendicular to the scattering area.

3 illus, 6 ref

002250   Parija B;Badapanda T;Senthil V;Rout S K; Panigrahi S (Physics Dep, National Institute of Technology, Rourkela-769 008, Email: badapanda.tanmaya@gmail.com) : Diffuse phase transition, piezoelectric and optical study of Bi_0.5Na_0.5TiO₃ ceramic. Bull Mater Sci 2012, 35(2), 197-202.

Bismuth sodium titanate, Bi_0.5Na_0.5TiO₃ (BNT) is considered to be an excellent candidate for a key material of lead-free dielectric ceramics. In this study, we propose the dielectric and optical study of single phase BNT powder prepared by solid-state reaction route. The phase formation and structural study were done by X-ray diffraction (XRD) which shows well developed crystallite with a pure perovskite phase. The ceramic was sintered at different temperatures from 1050°C to 1175°C to study the effect of sintering temperature on the morphology and density. It was found that the sample sintered at 1150°C shows the highest density. The microstructure of the ceramic was investigated by scanning electron microscopic (SEM) technique. The temperature-dependent dielectric study of the sample sintered at 1150°C was done in the frequency range of 50 kHz-1 MHz which shows a diffuse phase transition. The piezoelectric constant (d₃₃) was found to be 41 pCN^-1. The P-E hysteresis loop confirms the ferroelectric behaviour in the ceramic. The UV-Vis spectrum indicated that the Bi_0.5Na_0.5TiO₃ ceramic has an optical band gap of 2.94 eV.

9 illus, 24 ref

002249   Padmanabhan T (IUCAA, Post Bag 4, Pune Campus Univ, Ganeshkhind, Pune-411 007, Email: paddy@iucaa.ernet.in) : Quest for power. Resonance 2012, 17(5), 436-40.

The practical necessity for developing steam power came from the rapid deforestation in England in the seventeenth century.

6 illus, 3 ref

002248   Manoj Kumar (Physics Dep, Muzaffarpur Institute of Technology, Muzaffarpur-842 003) : Importance of optical oscillator strengths(OOS) in atomic and molecular physics with special references to P V, S VI, Cl VII, Ar III and K IX. Bull pure appl Sci-Sect D 2012, 31(2), 197-9.

Reported the importance of the Optical Oscillator strengths with special reference to the inner-Shell excitation (1s<6>2 2s² 2p⁶ 3s ²s^e → 1s² 2s² 2p⁵ 3s^{2 2}p^o). Transition in P V, S VI, Cl VII, Ar VIII and K IX [1] ions of the Sodium isoelectronic sequence and discussed the discrepancies in both the forms of Optical Oscillator strength. The results have been compared from At. Data tables of E.C1ementi and C.Roetti [2]. CI method was extensively used by Tiwary and co-workers [1,3] and also independently by Tiwary [4,5,6]. Hibbert, Kingston and Tiwary [7] calculated the transition probabilities for many atoms which became a milestone for further research. Idea of using HartreeeFock method to calculate oscillator strength was extensively used by Burke, Tiwary and Kingston [8].

9 ref, 1 table

002247   Mandal G;Anil Kumar;Sharma D C (NO, Mass Standards, National Physical Laboratory, Council of Scientific an, Dr. K.S. Krishnan Road, new Delhi, Email: goutam@nplindia.org) : Stability of the mass values of national prototype kilogram. Mfg Technol Today 2012, 11(6), 27-30.

It is well known fact that out of seven SI base units, only "kilogram" is still an artifact. Since kilogram has no link with any Physical Constants, measurement of International Prototype of the Kilogram (IPK) is not possible and only considered equal to exactly "1 kg" immediately after cleaning and washing by the method used at the International Bureau of Weights and Measures (BIPM). Although a lot of R & D is going on throughout the world to link the kilogram to physical constant like Plank Constant, Avogadro Constant etc. The National Physical Laboratory, India (NPLI) is the custodian of National Prototype of the Kilogram (NPK) No. 57, which was provided by the BIPM in 1958 after its first calibration in 1955. The NPK has been recalibrated in 1985, 1992 & 2002 so far at the BIPM. Beside this, other derived parameters like Force and Hardness Standards, Pressure and Vacuum Standards, Fluid Flow Standards etc. are directly related to Mass Standards. Now-a-days Chemical Metrology also requires traceability of Mass Standards. Therefore, stability of the NPK is a very important issue and the instability factors should be taken into consideration for every measurement. From the previous data, the change in mass values are estimated 218 mg from 1955 to 1985 (7.3 mg/year), 36 mg from 1985 to 1992 (5.1 mg/year) and 24 mg from 1992 to 2002 (2.4 mg/year) between after cleaning and washing of previous calibration to before cleaning and washing of next calibration. Now, the recalibration period of NPK is maximum 10 years. In this paper, the BIPM method, NPL, UK formula and NMIJ, Japan formula are used to evaluate the change in mass values of NPK No. 57.

4 illus, 1 table, 9 ref

002246   Lal T (NO, National Physical Laboratory, New Delhi-110 012) : Quality assurance and best calibration & measurement capability in mass measurements. Mfg Technol Today 2012, 11(6), 18-24.

International standard ISO/I EC 17025:2005 tells about one and only one thing i.e. Competence of testing and calibration laboratories. Demonstrated conformance to ISO/I EC 17025:2005 is a demonstration of such competence. The demonstration of conformance shows that the laboratory has the people, with the skills and knowledge, the environment with the facilities and equipment, the quality control and the procedures that are required to produce valid and reliable measurement results. Thus assuring quality of the measurement results is the main objective behind the principles of the ISO/I EC 17025, The validity, reliability and best calibration & measurement capability are the main factors which indicate the degree of quality of the measurement results of a testing or calibration laboratory. Necessary guidelines for achieving quality assurance and producing best calibration and measurement results in mass measurement have been outlined in this paper.

10 ref

002245   Khan Z R;Zulfequar M;Khan M S (Physics Dep, Jamia Millia Islamia, New Delhi-110 025, Email: mskhan@jmi.ac.in) : Structural, optical, photoluminescence, dielectric and electrical studies of vacuum-evaporated CdTe thin films. Bull Mater Sci 2012, 35(2), 169-74.

Highly-oriented CdTe thin films were fabricated on quartz and glass substrates by thermal evaporation technique in the vacuum of about 2 x 10^-5 torr. The CdTe thin films were characterized by X-ray diffraction (XRD), UV-VIS-NIR, photoluminescence spectroscopy and scanning electron microscopy (SEM). X-ray diffraction results showed that the films were polycrystalline with cubic structure and had preferred growth of grains along the (111) crystallographic direction. Scanning electron micrographs showed that the growth of crystallites of comparable size on both the substrates. At the room temperature, photoluminescence spectra of the films on both the substrates showed sharp peaks with a maximum at 805 nm. This band showed significant narrowing suggesting that it originates from the transitions involving grain boundary defects. The refractive index of CdTe thin films was calculated using interference pattern of transmission spectra. The optical band gap of thin films was found to allow direct transition with energy gap of 1.47-1-50 eV. a.c. conductivity of CdTe thin films was found to increase with the increase in frequency whereas dielectric constant was observed to decrease with the increase in frequency.

9 illus, 1 table, 32 ref

002244   Khan S A (Engineering Dep, Salalah College of Technology (SCOT), Salalah, Sultanate of Oman, Email: rohelakhan@yahoo.com) : How many equivalent resistances?. Resonance 2012, 17(5), 468-75.

It is straightforward to construct the set of equivalent resistance for circuits constructed from a bunch of four or five equal resistors. But as the bunch size increases it becomes difficult to find the order of the set of equivalent resistances. Even the computer programs runs out of memory. Also present an analytical result using simple mathematical machinery. The size of the set is shown to be less than 2.618ⁿ.

3 illus, 6 ref

002243   Kathayat K;Panigrahi A;Kar S (Physics Dep, North Orissa University, Baripada-757 003, Odisha, Email: kathayatkiran@yahoo.in) : Electrical and magnetic properties of (Ba₅LaTi₃V₇O₃₀)_1-x(BiFeO< v>3)_x solid solution for different values of x. Bull pure appl Sci-Sect D 2012, 31(2), 173-85.

The solid solution (Ba₅LaTi₃V₇O_301-x (BiFeO₃)_x with x ranging from o to 0.5 were synthesized by high temperature solid-state reaction. X-ray diffraction (XRD) measurements show separate reflection peaks corresponding to both Ba₅LaTi₃V₇O₃₀ (BL TV) and BiFeO₃ (BFO) which confirms the formation of solid solution instead of any new compound. The electrical properties (i.e., dielectric constant, loss tangent and ac conductivity) were studied by using complex impedance spectroscopy in a wide range of temperature (RT -773K). It is observed that Tc increases significantly upto x=0.3 followed by decrease in T_c at x=O.4 and again it increases for x=0.5. Magnetization study was done through VSM which shows the presence of ferromagnetic property' for x<62>0.3 so, predominately behaving as multiferroics in this range.

5 illus, 2 tables, 16 ref

002242   Karande S K;Raghuwanshi F C (Vidnyan Mahavidyalaya, , Malkapur, Dist Buldana) : Silar deposition of nanostructre CdS thin films on glass substrates with ultrasonification. Bull pure appl Sci-Sect D 2012, 31(2), 207-13.

Glass substrate modified with ultrasonic cleaning were used to deposit CdS thin films in the process of successive ionic layer absorption and reaction [SItAR]. The films were characterized by X -ray diffraction, u. v. absorption and atomic force microscopy [AFM]. AFM showed that after ultrasonic cleaning substrate were in favor of the growth of films by comparison with the commercial glass slide. The deposition rate of the films was faster after the ultrasonification of glass substrate.

4 illus, 14 ref

002241   Dhumale V A;Shah P V;Sharma R B;Tanabe K (Applied Physics Dep, Defence Institute of Advanced Technology, Girinagar, Pune-411 025, Email: rbsharma@diat.ac.in) : Effects of particle size and surrounding media on optical radiation efficiencies of spherical plasmonic metal nanoparticles. Bull Mater Sci 2012, 35(2), 143-9.

The optical radiation efficiency (η), the ratio of scattering cross-section to extinction cross-section, of spherical metal nanoparticles (M = Al, Ag, Au and Cu) surrounded by glass and water was calculated using classical electrostatics. The effect of varying particle diameter (<126>100 nm) on η was also studied for free space wavelengths in the range of 400-1200 nm. The variations in the value of η with the diameter (d) of the metal nanoparticles were calculated on the basis of quasi-static approximation. The η increases with the size of metal nanoparticles. Corresponding to a metal nanoparticle, η was found to exhibit a sharp dip (η_dip) at a characteristic wavelength (λ_ηM in a particular medium (μ = air, glass and water). (λ_μM was independent of particle size. The (λ_medium)_M was found to be slightly blue shifted for all metal nanoparticles surrounded by glass or water with respect to those in the air.

8 illus, 3 tables, 18 ref

002240   Choudhary S K;Singh B K;Singh K P;Gita Kumari;Kushwaha J P (University Dep of Physics, T M B University, Bhagalpur) : Double gate and ultrathin body MOSFET. Bull pure appl Sci-Sect D 2012, 31(2), 201-5.

Author discussed the impact of energy quantization on the direct tunneling gate leakage current using the double gate and ultrathin body MOSFET including the impact of threshold voltage control solutions.

12 ref, 2 illus

002239   Balwinder Kaur;Bhat M;Licci F;Ravi Kumar; Bamzai K K;Kotru P N (Physics and Electronics Dep, Jammu Univ, Jammu-180 006, Email: pnkotru@rediffmail.com) : High resolution X-ray diffraction studies on unirradiated and irradiated strontium hexaferrite crystals. Bull Mater Sci 2012, 35(2), 253-8.

High-resolution X-ray diffraction technique, employing a three-crystal monochromator-collimator combination is used to study the irradiation induced defects in flux grown Sr-hexaferrite crystals irradiated with 50 MeV Li³⁺ ion beams at room temperature with a fluence value of 1 x 10¹⁴ ions/cm². The diffraction curves of the irradiated crystals suggest the possibility of creation of low angle grain boundaries and other point/clusters of defects causing amorphization in the irradiated crystals. The perfection of the irradiated and unirradiated (0001) cleaved surfaces of the crystals is studied using the bulk method of X-ray topography. The topographs supplement the findings suggestive of modifications in the crystalline quality of SrFe₁₂O₁₉ on irradiation with SHI of Li³⁺. Etching of the (0001) cleaved surfaces in H3PO4 at 120° C suggests that the dissolution characteristics of the surfaces get affected on irradiation with SHI of Li³⁺, besides supporting the findings of HRXRD and X-ray topography regarding modifications in the perfection of SrFe₁₂O₁₉ on irradiation.

5 illus, 45 ref

002238   Anbarasan P M;Vasudevan K;Senthil Kumar P; Prakasam A;Geetha M;Lalithambigai K (Physics Dep, Periyar Univ, Salem-636 011, Email: anbarasanpm@gmail.com) : Structural and spectral properties of 4-phenoxyphthalonitrile dye sensitizer for solar cell applications. Bull Mater Sci 2012, 35(2), 265-75.

The geometries, electronic structures, polarizabilities and hyperpolarizabilities of organic dye sensi-tizer 4-phenoxyphthalonitrile was studied based on ab initio HF and density functional theory (DFT) using the hybrid functional B3LYP. Ultraviolet-visible (UV-Vis) spectrum was investigated by time dependent DFT (TD-DFT). Features of the electronic absorption spectrum in the visible and near-UV regions were assigned based on TD-DFT calculations. The absorption bands were assigned to π →π transitions. Calculated results suggest that the three excited states with the lowest excited energies in 4-phenoxyphthalonitrile was due to photo-induced electron transfer processes. The interfacial electron transfer between semiconductor TiO₂ electrode and dye sensitizer 4-phenoxyphthalonitrile was due to an electron injection process from excited dye to the semiconductor's conduction band. The role of phenoxy group in 4-phenoxyphthalonitrile in geometries, electronic structures and spectral properties were analysed.

6 illus, 5 tables, 51 ref