017014   Kumar K;Pal K (Applied Science Humanities (Physics) Dep, IMS Engineering College, Ghaziabad, Email: Dr.kushalkumar@gmail.com) : High input impedance voltage mode universal biquad filter. Indian J pure appl Phys 2010, 48(4), 292-6.

A high input impedance voltage mode universal biquad filter using two operational transconductance amplifiers (OTAs), one current feedback amplifier (CFA), two capacitors and one grounded resistor has been studied. The new circuit has three inputs and single output and can realize all the standard filter functions, that is low pass (LP), high pass (HP), band pass (BP), notch (NH), and all pass (AP) filters without changing the circuit topology. The proposed circuit offers several advantages such as orthogonal controllability of the resonance frequency ω0 and quality factor Q. There is no need of one more active element for the realization of all pass filter, high input impedance and low output impedance which is suitable for cascading for higher order filter transfer functions and low active and passive sensitivity performance.

5 illus, 27 ref

017013   Kanhekar S R;Pawar P;Bichile G K (Physics Dep, Dr Babasaheb Ambedkar Marathwada Univ, Aurangabad-431 004, Email: srkanhekar@gmail.com) : Thermodynamic properties of electrolytes in aqueous solution of glycine at different temperatures. Indian J pure appl Phys 2010, 48(2), 95-9.

Ultrasonic velocity, density and viscosity have been measured for NaCl and MgCl₂ in aqueous glycine solution at 298.15, 303.15 and 308.15K. The thermodynamic parameters such as adiabatic compressibility, acoustic impedance, intermolecular free length and relative association have been obtained from the experimental data for all the mixtures, with a view to investigate the exact nature of the molecular interaction. Adiabatic compressibility and intermolecular free length decrease with increase in concentration and temperature. Acoustic impedance and relative association are almost constant with increase in temperature and gradually increase with concentration of solutes. These parameters have been further used to interpret the hydrophilic part of the solute and molecular interactions in the mixtures.

8 illus, 3 tables, 19 ref

017012   Indulal C R;Raveendran R (Physics Dep, S N College, Kollam-691 001, Email: cr_indulal@yahoo.com) : Synthesis, characterization and dielectric studies of cerium phospho iodate and cadmium doped cerium phospho iodate in nano form. Indian J pure appl Phys 2010, 48(2), 121-6.

Nano particles of cerium phospho iodate (CPI) and cadmium doped cerium phospho iodate (Cd doped CPI) have been prepared by chemical co-precipitation method. The particle size and crystal structure of CPI and Cd doped CPI nano powder are characterized by X-ray diffraction (XRD). The surface morphology of the samples is studied from SEM images. The FTIR spectrum is used to study the stretching and bending frequencies of molecular groups in the sample. Temperature and frequency dependence of the dielectric constant and ac electrical conductivity are studied for 0.02 and 0.04 molarities of the dopant. The dielectric permittivities of nano sized samples are evaluated from the observed capacitance values in the frequency range 100 Hz-1 MHz and in the temperature range 50°-100°C. It has been found that with decreasing frequency, the dielectric constant increases much more obviously for the doped sample. As the temperature increases more and more dipoles are oriented resulting in an increase in the values of molecular dipole moment. Space charge polarization and rotational polarization play a crucial role in the dielectric behaviour of the nano sized material. From the permittivity studies, ac electrical conductivity is evaluated. The dielectric and ac electrical conductivity studies of the samples are made at different molarities of the dopant.

7 illus, 20 ref

017011   Hasan M N;Matsushita T;Muralidhar M (Physics Dep, Chittagong Univ, Chittagong-4331, Bangladesh, Email: nhasan72bd@yahoo.com) : Optimization of matrix chemical ratio for high critical current density J_c in (Nd, Eu, Gd)Ba₂Cu₃O_y superconductors. Int J pure appl Phys 2009, 5(1), 49-54.

Investigated the magnetic field dependence of the critical current density J_c in (Nd, Eu, Gd) Ba₂Cu_3y samples with various Nd: Eu: Gd ratios in the rare earth site at 77.3 K. It was found that all the samples showed well-developed peak effect depended on the chemical ratio in the matrix. We have also showed that a maximum flux pinning can be achieved in the whole magnetic field when 3 mol% NEG-211 particles were dispersed in a (Nd, Eu, Gd)Ba₂Cu₃O_y matrix with an optimum Nd: Eu: Gd ratio. The enhancement of peak critical current density J_cp with increasing matrix ratio suggests that the maximum pinning effect can be achieved by combining the appropriate concentration of 211 phase particles with the optimum chemical ratio in the matrix.

2 illus, 1 table, 24 ref

017010   Gupta S;Sircar R;Prakash D;Tripathi B (Physics Dep, Feroze Gandhi College, Raebareli-229 001, Email: ratna_fgcrbl@rediffmail.com) : Optimization of recombination parameters to enhance minority carrier lifetime. Int J pure appl Phys 2009, 5(2), 133-41.

The study of recombination mechanism and its control parameters in multicrystalline silicon solar cell is very essential to achieve high cell efficiency for photovoltaic application. Recombination Statistics of various impurity elements in crystalline silicon solar cell is strongly determined by recombination parameters, i.e. the bulk carrier recombination lifetime τ_b, and the effective surface recombination velocity (SRV) at the rear of the cell. Study was performed using Shockley-Read-Hall (SRH) recombination and modeling is done by the simulation software PC1D to calculate output parameters of PVC. Obtained larger recombination lifetime of 22.6 ms for an impurity (vanadium) at injection level of 4.498 x 10¹⁵ cm^-3 for base resistivity 1 Ωcm & surface recombination velocity 10³ cm s^-1 and hence efficiency of PVC increased to the value 19.06% with respect to the chosen base model.

2 illus, 5 tables, 20 ref

017009   Gunasekaran S;Anita B;Seshadri S (Physics Dep, D G Vaishnav College, Chennai-600 106, Email: anitabharathan@yahoo.com) : Vibrational spectroscopy study of diethyl carbamazine using semi-empirical calculations. Indian J pure appl Phys 2010, 48(3), 183-91.

Study of vibrational spectra of diethyl carbamazine is difficult to interpret by normal coordinate analysis because of the complex structure and low symmetry of the molecule. The vibrational spectra of the molecule have been studied completely and various normal modes with great wave number accuracy have been identified. The equilibrium geometries and harmonic frequencies of the compounds diethyl carbamazine are determined and analysed using the semi-empirical methods AM1 and PM3. The differences between the observed and calculated wavenumber values in the molecule are marginal. Thermodynamic properties like entropy, heat capacity, zero point energy have been calculated for the molecule. Since the structure of the diethyl carbamazine is very complex, it is very difficult to calculate the above mentioned parameters using empirical techniques HR and DFT. Therefore, in the present study, the semi-empirical techniques are only applied to the compound to study its molecular parameters.

3 illus, 5 tables, 17 ref

017008   Getinet T (Physics Education Dep, Addis Ababa Univ, PO Box 126/1048, Addis Ababa, Ethiopia, Email: tesfa_get@yahoo.com) : High field DC electrical conductivity in silicon. Indian J pure appl Phys 2010, 48(3), 192-5.

Analytical expression for the conductivity of electrons in silicon in the presence of high dc electric field has been derived in the present paper by considering the asymmetric distribution function of electrons which is a function of electric field. This has resulted in dependence of the net number of electrons and their conductivity on electric field. The conductivity of electrons decreases drastically as electric field increases because of high dc electric field. The drift velocity of electrons experiences a transient effect and the time taken by electrons moving between successive collisions decreases as a result of quantum emission. The result of the present paper might be very important in characterising semiconductor devices where high field is primarily of concern.

2 illus, 7 ref

017007   Gawande W J;Yawale S S;Yawale S P (P.G. Dep of Physics, Government Vidarbha Institute of Science and Humanities, Amravati) : Optical properties of CuO-B₂O₃ glasses. Vidarbha J Sci 2010, 5(2), 34-8.

The optical adsorption and transmission spectra in (UV-VIS) have been recorded in the wavelength range 350-800 nm for different compositions of CuO-B₂O₂ glasses. The various optical properties such as absorption coefficient (α'), optical energy gap (E_opt), refractive index (n_o), optical dielectric constant (ε' ∞), measure of extent of band tailing (ΔE), constant (β) and ntio of carrier concentration to the effective mass (N/m*) for different glasses have been reported. The effects of composition of glasses on these parameters have been discussed. It has been indicated that a small modification of the glasses can lead to an important change in all the optical properties. These results are interesting showing non linear behaviour for all these parameters investigated. The optical parameters are found to be almost the same for different glasses in the same family.

4 illus, 1 table, 12 ref

017006   El-Dahshan E;Radi A;El-Bakry M Y;El Mashad M (Physics Dep, Faculty of Sciences, Ain Shams Univ, Abbasia, Cairo, Egypt, Email: e_eldahshan@yahoo.com) : Artificial neural network modeling in heavy ion collisions. Int J pure appl Phys 2009, 5(1), 1-14.

The neural network (NN) model and parton two fireball model (PTFM) have been used to study the pseudo-rapidity distribution of the shower particles for C^{12, O16, Si28 and S32 on nuclear emulsion. The trained NN shows a better fitting with experimental data than the PTFM calculations. The NN is then used to predict the distributions that are not present in the training set and matched them effectively. The NN simulation results prove a strong presence modeling in heavy ion collisions.}

3 illus, 33 ref

017005   Dushyant Pradeep;Ashok Kumar;Naithani U C (Physics Dep, H N B Garhwal Univ, Campus Pauri, Garhwal, Uttarakhand-246 001, Email: dushyant_pradeep@yahoo.co.in) : Field dependent dielectric behaviour of Ba_1-xCa_xTiO₃ ferroelectric perovskites. Indian J pure appl Phys 2010, 48(3), 220-4.

Electric field dependence of complex dielectric constant of Ba_1-xCa_xTiO₃ ferroelectric crystal in paraelectric phase has been studied by using the method of double times thermal Green's function and Kubo formalism. A general expression is derived from the Silverman-Joseph Hamiltonian by taking into account the change of mass as well as harmonic force constant between impurity atom and host lattice atoms with fourth order phonon coordinates. The frequency, temperature and electric field dependent dielectric constant of Bai_-xCa_xTiO₃ crystal has been investigated. The dielectric constant increases with increase in temperature as well as with the applied electric field. The results are compared with the previous experimental and theoretical results.

4 illus, 34 ref

017004   Dushyant Pradeep;Ashok Kumar;Naithani U C (Physics Dep, H N B Garhwal Central Univ, Campus Pauri (Garhwal), Uttarakhand-246 001, Email: dushyant_pradeep@yahoo.co.in) : Dependence of specific heat on electric field in Ba_1-xCa_xTiO₃ ferroelectric perovskites. Indian J pure appl Phys 2010, 48(4), 276-81.

The electric field dependence of the specific heat of an anharmonic Ba_1-xCa_xTiO₃ ferroelectric crystal has been calculated in its paraelectric phase from Silverman-Joseph Hamiltonian augmented with fourth order phonon coordinates using double times Green's functions. The electric field dependent soft mode contribution to the specific heat is described by appropriate Einstein terms. The variation of the specific heat with temperature and defect parameters has been discussed for different values of field strengths. The effect of defects on specific heat can be observed in the presence of anharmonicity. The specific heat decreases with increase in external field and increases with increase in temperature which is in agreement with the previous results. As the Curie temperature is approached, the Cochran soft mode is held to be responsible for the anomalous behaviour of specific heat.

2 illus, 30 ref

017003   Duhan S;Sunita Devi;Srivastava M (Physics Dep, Govt S S S Sanghi (Rohtak), Haryana, Email: surender6561@yahoo.co.in ) : Characterization of nanocrystalline Ag/SiO₂ nanocomposites and synthesis by wet chemical method. Indian J pure appl Phys 2010, 48(4), 271-5.

The silver/silica nanocomposites have been successfully prepared by the sol-gel process. After drying in air at 70°C for 30 min, samples are heat treated in air at 150, 300 and 500°C. Characterizations have been made by ultraviolet-visible (UV-VIS-NIR), X-ray diffraction (XRD), Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). Mechanisms of silver clusters formation in the densified silica matrix with respect to thermal treatment have been studied.

5 illus, 24 ref

017002   Dixit G;Singh J P;Srivastava R C;Agrawal H M; Choudhary R J;Gupta A (Physics Dep, G B Pant Univ of Agriculture & Technology, Pantnagar-263 145, Email: gagandikshit@yahoo.in) : Structural and magnetic behaviour of NiFe₂O₄ thin film grown by pulsed laser deposition. Indian J pure appl Phys 2010, 48(4), 287-91.

NiFe₂O₄ thin film has been grown on Si (100) substrate by pulsed laser deposition (PLD) technique. The microstructure of the film was characterised by X-ray diffractometer (XRD) and atomic force microscopy (AFM). Magnetic characterisation has been done by vibrating sample magnetometer (VSM). In order to have comparative study, the bulk (target used for PLD) has also been characterised by XRD and VSM. Grazing incidence X-ray diffractometer (GIXRD) pattern of the film confirms the single spinel phase. Results of AFM have shown that the average grain size of the prepared film is of the order of 47 nm and surface roughness of the order of 3-4 nm. VSM measurements indicate that for the film, both the saturation magnetisation and the coercivity are greater than that of bulk.

5 illus, 27 ref

017001   Dhavala S K;Chandra Mouli K (Solid Styate Physics & Materials Science Research Laboratories, Physic, Andhra Univ, Visakhapatnam-530 003, Email: dhavalasanthoshkumar@gmail.com ) : Effect of sintering temperature on electrical properties of Mn_0.5Zn_0.5Fe₂O₄ nanoscale particles prepared by Co-precipitation method. Int J pure appl Phys 2009, 5(2), 149-55.

Magnetic Nano particles of Mno.5Zno.5Fe2O4 have been synthesized using Co-precipitation technique. During the experimental investigation, MnZn ferrites exhibited interesting structural, electrical and magnetic properties. Formation of spinel phase was identified using X-Ray diffraction (XRD) technique. The ferrite compound prepared in the laboratory exhibited cubic spinal symmetry. The Lattice constant of the compound was determined to be 8.324 A°. The morphology and size of the crystallite was found by Transmission Electron Microscopy (TEM). The magnetic properties were studied using Vibration Sample Magnetometer (VSM) and the saturation magnetization (Ms), remenant magnetization (Mr) and the Coercivity force (He) values were evaluated. Electrical properties of the samples were quantified using standard two-probe method.

4 illus, 1 table, 17 ref

017000   Devinder Singh;Jaggi N;Sathe V;Nafa Singh (Physics Dep, D S College, Karnal-132 001, Email: ds_kuk@yahoo.com) : Vibrational analysis of 1-bromooctane. Indian J pure appl Phys 2010, 48(3), 172-82.

Fourier transform infrared and Raman spectra of the organic compound 1 -bromooctane have been recorded in the range 4000-400 cm^-1 and 3500-100 cm^-1, respectively. A detailed vibrational analysis in terms of assignment of the observed frequencies of this molecule for its four most probable conformations in liquid phase, having symmetries C_s and C₁, has been done using normal co-ordinate calculations. The force-field transferred from already studied lower chain bromo-alkanes is subjected to refinement so as to fit the observed infrared and Raman frequencies with those of the calculated ones. The potential energy distribution has also been calculated for each mode of vibration of the molecule for the most probable conformations present in its liquid phase.

3 illus, 2 tables, 27 ref

016999   Deo S D (NO, N.S. Science and Arts College, Bhadrawati, Dist. Chandrapur, Maharashtra-442 902, Email: s_deo01@yahoo.com) : Cylindrically symmetric in homogeneous string universe in bimetric relativity. Vidarbha J Sci 2010, 5(2), 18-21.

Aims to investigate the behavior of the cosmic cloud string in the ylindrically symmetric inhomogeneous cosmological model in Bimetric Relativity.

ref

016998   Chowdhury I;Dasgupta S P (Civil and Structural Engineering Dep, Petrofac International Limited, Sharjah, U.A.E., Email: Chowdary@oerrofac.com) : Dynamic analysis of piles under rocking motion. Indian Geotech J 2009, 39(4), 360-86.

An analytical solution is given for the vibration of piles under rocking/rotational mode coupled with lateral translation. In many cases it has been found that this coupled motion is critical and often governs the design. Both long and short piles and the inertial effect of the pile have been incorporated in the analysis. The solution takes into account for the variation of shear modulus with depth and the effect of partial embedment of the pile. Wherever possible, the results have been compared with the existing solutions and the results have been presented graphically.

9 illus, 4 tables, 21 ref

016997   Borthakur T K;Shyam A (NO, Centre of Plasma Physics, Sonapur-782 402, Email: tkborthakur@yahoo.co.uk) : Analysis of axial neutron emission pulse from a plasma focus device. Indian J pure appl Phys 2010, 48(2), 100-3.

Intense burst of neutrons have been observed from a 5 kj Mather type plasma focus device operated in a pressure of around 0.4 torr of deuterium medium in axial direction. The emitted neutrons, which are accompanied by a strong hard X-ray pulse, are found to be having energy up to 3.97 MeV in the axial direction of the device. The axial neutrons emitted from the device appear to be influenced by deuteron ions emitted in the same direction.

5 illus, 20 ref

016996   Boltcho A (NO, , Laborecka 6, 040 11 Kosice, Slovakia) : Example of evident failure of special relativity transformations by using at a simple physical situation. Int J pure appl Phys 2009, 5(2), 117-19.

This paper demonstrates an example of evident failure of special relativity transformations by using at a simple physical situation.

3 illus, 1 ref

016995   Bari R H;Patil L A (Nanomaterials Research Laboratory, P G Dep of Physics, Pratap College, Amalner-425 401, Email: plalchand_phy_aml@yahoo.co.in) : Synthesis and characterization of bismuth selenide thin films by chemical bath deposition technique. Indian J pure appl Phys 2010, 48(2), 127-32.

Thin films of bismuth selenide were prepared by chemical bath deposition technique onto glass at 55°C. The deposition parameters such as time, temperature of deposition and pH of the solution were optimized. The set of films having different elemental compositions was prepared by varying Bi/Se ratio from 0.93 to 2.03. The composition, morphology, structure, optical absorption and electrical conductivity of the films were studied. Characterization includes X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDAX), absorption spectroscopy and electrical conductivity.

8 illus, 3 tables, 16 ref

016994   Balasubramanian V;Sekar C (Physics Dep, Sona College of Technology, Salem-636 005, Email: sekar2025@gmail.com) : Fabrication and study of light weight inexpensive portable solar cooker. Int J pure appl Phys 2009, 5(2), 175-82.

Light weight inexpensive portable solar cooker (LIPS) is fabricated and its performance as solar cooker is studied. The size of the cooker is so small (0.3743 m2) that, it can be easily transported from one place to other. Its performance is analysed with the help of an aluminium vessel which acts as an absorber. This vessel is painted with dull finished black board paint. Various food materials are cooked and the time consumed is rioted. The time consumption by this type of cooker is acceptable for domestic cooking purpose. The fabrication cost of this cooker is also affordable for typical Indian lower middle class people. The objective of this study is to provide inexpensive cooking device for poor/lower middle class people and does not undertake comparative performance analysis with any type of commercial solar cooking devices available in the market.

6 illus, 3 tables, 10 ref

016993   Anuradha P;Anu Kaliani A (P.G. Dep of Physics, Vellalar College for Women, Erode, Email: anusham_33@yahoo.co.in ) : Surface characterization and antibacterial activity of plasma treated polystyrene thin film. Int J pure appl Phys 2009, 5(2), 157-64.

Cold plasma treatment has become a versatile technique for enhancing surface chemistries of polymers without bulk alteration. This treatment is significant in bringing microscopic and macroscopic surface changes without mortifying the polymer. With bulk properties remaining the same, surface modified polymers have many practical applications. Polystyrene is an extensively used polymer. It is used in packaging industry and has domestic and biomedical applications. This paper details the effects of cold plasma treatment on polystyrene thin film and antibacterial activity of the polystyrene thin film after plasma treatment. Cold plasma, which is produced in a glow discharge d.c plasma chamber, is used to modify the surface of the fabricated polystyrene thin film. Polystyrene thin films were treated in cold plasma for different exposure times with an applied voltage of 350V to the electrodes and a pressure of 0.8 mb maintained in the chamber. The surface properties were characterized by FTIR, SEM and wettability studies. The antibacterial activity was studied by Agar Diffusion Test. Results show introduction of hydroxyl group, increase in hydrophyllicity, very weak roughness change and antibacterial activity of polystyrene thin film surface after plasma treatment.

3 illus, 2 tables, 11 ref

016992   Alkilany S A (Mathematics Dep, Faculty of Education, Kafr El-Sheikh Univ, Egypt) : Collision of positrons with positronium. Int J pure appl Phys 2009, 5(2), 101-5.

A computational code based on an elaborate coupled static approach is developed for the treatment of the elastic and inelastic scattering of positrons by positroniums. The inelastic channel is chosen as a mixture of 2s- and 2p-states. The 2x2 reactance matrices as well as the corresponding partial cross sections corresponding to 0 ≤ I ≤ 6 are determined for the first time at wide range of total energies below the second excitation threshold of the positronium, i.e. below 6.044 eV. The effect of adding the polarization potential to the first channel is explored. Partial and total cross sections are also calculated at high energies (between 10 and 500 eV) in order to compare present results of positronium formation with those obtained by other authors for inelastic collisions of positron with hydrogen atoms.

5 illus, 6 tables, 12 ref

016991   Al-Seady M (Physics Dep, Faculty of Science, Alexandria Univ, Alexandria, Egypt, Email: malseady@cosmic.utah.edu) : New prospective of the space - time dimensions of the visible universe. Int J pure appl Phys 2009, 5(2), 143-8.

No one claims creating the whole universe and everything in it except Allah Almighty as had been declared in all holy books especially the Quran. So, just trying to comprehend the time and space dimensions of the universe though they are gigantic because they must imply with the unlimited and magnificent power of the Creator himself yet, one must think that both dimensions should still have limitation boundaries and they are not infinite. Scientific gestures from some verses of the Quran and correct and verified Hadeeth if could be scientifically interpreted correctly it may give us clues about that dilemma and that the answer was there more than 1400 years ago.

2 illus, 11 ref

016990   Abdullah O G;Rasin F A;Al-Dhahir T A (Physics Dep, College of Science, Sulaimani Univ, Iraq, Email: omedghareb@yahoo.om) : Finite element simuation of alumina ceramic powder compaction. Int J pure appl Phys 2009, 5(1), 15-31.

The mechanical behaviour of alumina ceramic powder during compaction, unloading and ejection are analyzed using Finite Element Methods (FEM), in which the powder is modeled as an elastic-plastic continuum material. The modify Drucker-Prager Cap (DPC) model was chosen as the yield surface of the medium. The elastic properties and plastic parameters of the model were expressed as a function of density, from which realistic powder properties are generated and fed into ABAQUS finite element code; and the constitutive modeling of the frictional behaviour of the powder in the die is modeled by Coulomb's friction low. Good agreement between the experimental and FEM results are observed, which demonstrates that FEM can capture the major features of the powder behaviour during compaction.

14 illus, 24 ref

016989   Abdel-Raouf M A;Elkilany S A (Physics Dep, College of Science, UAEU, Al-Ain, P.O. Box: 17555, United Arab Amirates) : Resonance in positron-lithium scattering. Int J pure appl Phys 2009, 5(2), 93-100.

The appearance of intermediate states (also referred to as resonant states) in atomic, molecular and nuclear reactions is considered as the most interesting physical phenomena since the development of the quantum theory in the early thirties of the preceding century. The development of femtosecond lasers has tremendously enhanced the experimental identification of these states in chemical reactions. The main objective of the present work is to develop a unified mathematical formalism for the localization of resonant states in physical and chemical reactions. Numerical examples for the validity of this formalism will be demonstrated.

2 illus, 22 ref

015815   Zheludev A (Oak Ridge National Laboratory, , USA, Email: zheludevai@ornl.gov) : Magnetizing and heating quantum spin ladders. Pramana J Phys 2008, 71(5), 896.

Quasi-one-dimensional quantum spin liquids, such as weakly coupled even-legged 812 spin ladders or spin tubes, have a singlet non-magnetic ground state and gap in the excitation spectrum. Their low-temperature properties can be described in terms of triplet massive quasiparticles. These magnons possess some unique features due to the peculiar topology of one dimension. For example, two-particle interactions totally destroy single-particle states for certain energy and momentum transfers, resulting in the so-called termination of the magnon spectrum. At high field a Bose-Einstein condensation of these magnons produces a quantum spin solid phase, where conventional anti ferromagnetic order coexists with excitations that are totally outside conventional spin wave theory. At finite temperatures strong repulsion between quasiparticles leads to a universal renormalization of their masses and lifetimes. These diverse phenomena are best probed by neutron scattering experiments that directly measure the spin correlation functions and excitation spectra.

015814   Yethiraj M (NO, Bragg Institute, ANSTO, Lucas Heights, NSW 2234. Australia, Email: mohan. yethiraj@gmail.com) : Changes in the excitations related to the superconducting transition in V₃ Si. Pramana J Phys 2008, 71(5), 902.

In earlier studies of phonons in V 3Si, a gradual softening of the (h h 0) branch was observed and attributed to the martensitic transition in this compound, which preªcedes the onset of superconductivity by a few degrees K. In this work, the temperature dependence of the transverse acoustic branch along the h h 0 direction was studied in greater detail and it is shown that while the TA h h 0 mode starts to soften at relatively high temperatures ((F128><62>200 K), an anomalous inelastic peak, which is somewhat localized in q, occurs just below T_c. The intensity of this mode correlates extremely well with the onset of the superconducting phase and varies as the order parameter with temperature and applied field. The similarities in the phonon softening and Fermi surface anisotropy between this compound and the rare-earth nickel borocarbides suggests the existence of a common mechanism for the superconducting transition.

015813   Yakhmi J V (NO, Bhabha Atomic Research Centre, Mumbai-400 085, Email: yakhmi@barc.gov.in) : Molecule-based magnets. Bull Mater Sci 2009, 32(3), 217-25.

Conventional magnetic materials used in current technology, such as, Fe, Fe₂O₃, Cr₂O₃, SmCo₅, Nd₂Fe₁₄B etc are all atom-based, and their preparation/processing require high temperature routes. Employing self-assembly methods, it is possible to engineer a bulk molecular material with long-range magnetic order, mainly because one can play with the weak intermolecular interactions. Since the first successful synthesis of molecular magnets in 1986, a large variety of them have been synthesized, which can be categorized on the basis of the chemical nature of the magnetic units involved: organic-, metal-based systems, heterobimetallic assemblies, or mixed organic-inorganic systems. The design of molecule-based magnets has also been extended to the design of poly-functional molecular magnets, such as those exhibiting second-order optical nonlinearity, liquid crystallinity, or chirality simultaneously with long-range magnetic order. Solubility, low density and biocompatibility are attractive features of molecular magnets. Being weakly coloured, unlike their opaque classical magnet `cousins' listed above, possibilities of photomagnetic switching exist. Persistent efforts also continue to design the ever-elusive polymer magnets towards applications in industry. While providing a brief overview of the field of molecular magnetism, this article highlights some recent developments in it, with emphasis on a few studies from the author's own lab.

8 illus, 78 ref

015812   Wang J;Zhang Y;Xia H;Sheng J (Photo-Electronic Materials Lab, Ningbo University, Ningbo 315211, PR China, Email: cxycwjh@yahoo.com) : Growth of Nd<. Bull Mater Sci 2009, 32(2), 183-6.

Growth of Nd^{3+ doped lithium niobate crystals using Bridgman method has been reported. By means of the optimum conditions such as proper feed materials, sealed platinum crucibles, growth rate of 1-1.5 mm/h and temperature gradient of 30-35°C/cm across the solid-liquid interface under the furnace temperature of 1300°C, single crystals containing Nd3+ ion with 0.54 mol% concentration were obtained. X-ray diffraction and ICP-AES were used to characterize the crystals and its composition. The absorption, emission and fluorescence lifetime are also measured. Based on the Judd-Ofelt theory, we obtained the optical parameters of the crystal such as the luminescent quantum efficiency, the radioactive lifetimes, the branching ratios and the emission cross-section.}

6 illus, 2 tables, 16 ref

015811   Wagner R (NO, Institut Laue-Langevin (ILL), Grenoble, France, Email: wagner@ill.eu) : Scientific horizons at the Institute Laue-Langevin. Pramana J Phys 2008, 71(5), 888.

In order to maintain the scientific value of the ILL and to respond to the changing needs of its broad user community throughout Europe and beyond, in 2001 the Millennium Programme (Phase M-O, 2001-2008) was launched to boost the quality of ILL's experimental facilities. The ongoing renewal programme has been directed towards renewing some of the neutron delivery systems - neutron guides and beam tubes towards improvement of sample environment and installation of user-friendly data acquisition/handling systems, and in particular towards upgrading neutron instrumentation. Already at this stage, the upgrading of eleven instruments and some neutron delivery systems has increased the overall efficiency (expressed in terms of count rates) of ILL's instruments suite by more than a factor of 14. This does not only render the time for a neutron scattering experiment much shorter but, in particular, does open access to new scientific challenges such as in nanoscience and biology where often only small samples are available. In the recently launched Phase M-1 (2007-2013), five new instruments as well as new neutron guide systems will be built with the emphasis on neutron diffraction and spectroscopy with cold neutrons. This will further boost the application of neutron scattering techniques to materials science problems and to condensed matter research, and will keep the institute at the forefront of neutron science well beyond 2020.

015810   Wagh A G;Abbas S;Strobl M;Treimer W (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: nintsspd@barc.gov.in) : Bragg prism monochromator and analyser for super ultra-small angle neutron scattering studies. Pramana J Phys 2008, 71(5), 1171-5.

Desigs, fabricats and operats a novel Bragg prism monochromator-analyser combination. With a judicious choice of the Bragg reflection, its asymmetry and the apex angle of the silicon single crystal prism, the monochromator has produced a neutron beam with sub-arcsec collimation. A Bragg prism analyser with the opposite asymmetry has been tailored to accept a still sharper angular profile. With this optimized monochromator-analyser pair, attains the narrowest and sharpest neutron angular profile to date. At this facility, we have recorded the first SUSANS spectra spanning wave vector transfers Q ~ 10^{-6 Angstrom-1 to characterize samples containing agglomerates up to tens of micrometres in size.}

7 illus, 10 ref

015809   Tripathy P K;Patra A K;Sastry P U (Materials Processing Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: apatra@magnum.barc.gov.in) : Pore morphology of titanium and its oxide by small angle neutron scattering. Pramana J Phys 2008, 71(5), 1033-8.

Titanium metal bodies have been prepared from the sintered powder comªpacts of TiO₂ by a novel molten salt electrochemical approach, known as FFC Cambridge process. The phase and compositional characterizations of both Ti and TiO₂ have been carried out by X-ray diffraction. The pore morphologies of sintered TiO₂ pellet and the metallic Ti pellet, obtained after electrochemical reduction have been studied by SANS over a scattering wave vector q range of 0.003-3.5 nm^-1 using a double crystal diffracªtometer and a pin-hole collimated SANS instrument. In the case of reduced metal pellet, average pore size was found to be larger than that of the oxide pellet as the voids left behind after the oxygen atoms left the oxide matrix, could not coalesce.

5 illus, 1 table, 8 ref

015808   Treimer W (Mathematics Dep, Physics and Chemistry, University of Applied Sciences, Luxemburger Str, 10, D-13353 Berlin, Germany, Email: treimer@hmi.de) : Advances in neutron tomography. Pramana J Phys 2008, 71(5), 891.

In the last decade neutron radiograph (NR) and tomography (NCT) have experienced a number of improvements, due to the well-known properties of neutrons interacting with matter, i.e. the low attenuation by many materials, the strong attenuation by hydrogenous constituent in samples, the wavelength-dependent attenuation in the neighbourhood of Bragg edges and due to better 2D neutron detectors. So NR and CT were improved by sophisticated techniques that are based on the attenuation of neuªtrons or on phase changes of the associated neutron waves if they pass through structured materials. Up to now the interaction of the neutron spin with magnetic fields in samples has not been applied to imaging techniques despite the fact that it was proposed many years ago. About ten years ago neutron depolarization as imaging signal for neutron radiogªraphy or tomography was demonstrated and in principle it works. Now one can present much improved test experiments using polarized neutrons for radiographic imaging. For this purpose the CONRAD instrument of the HMI was equipped with polarizing and analysing benders very similar to conventional scattering experiments using polarized neutrons. Magnetic fields in different coils and in samples (superconductors) at low temperatures could be visualized. In this lecture a summary about standard signals (attenuation) and the more 'sophisticated' imaging signals as refraction, small angle scattering and polarized neutrons will be given.

015807   Tiwari S N;Dwivedi A K;Shukla S (Physics and Electronics Dep6iDr. R. M. L. Avadh University, , Faizabad-224 001, Email: sachida_shukla@yahoo.co.in) : Darlington pair amplifiers in cascade. Ultra Scient phys Sci 2009, 21(2), 253-8.

Qualitative analysis of two-stage Darlington pair amplifier is carried out. Enhancement in voltage and current gain is observed with distinct behaviour of bandwidth. This two-stage amplifier may be quite useful for amplification of small signals of mili-volts range and suitable for various analog electronics and communication applications.

8 illus, 12 ref

015806   Tiwari R K;Shukla H P (Physics and Electronics Dep, Dr. R.M.L. Awadh University, Faizabad) : Energy efficient portable electronic devices using reversible logic gates. Ultra Scient phys Sci 2009, 21(2), 443-50.

The new generations of Portable Electronic devices are intended to provide a wide range of information, services and receiving a large volume of information, data, image and video so on. Further, portable electronic devices have integrated and advanced function like multimedia portable communication, monitoring and control facilities including high resolution video transmission, selection of services and application by customer i.e. monitoring and control of industrial applications, weather forecasting, location services and connection with other transmission media as well as achieving higher level of security and authentication. Wide coverage of future Portable electronic device services being provided through portable devices are on the rise and new technologies put more computing power in these small devices. However, the slow up gradation of battery technology forms an ultimate constraint on running heavier application on these devices. To prolong battery life, many power saving techniques are being used at all levels of system design. In this paper, we have described the concept of the reversible logic gates which may be used for replacement of conventional logic gate in the design of digital integrated circuit for portable devices to reduce power dissipation resulting prolonged battery life.

2 illus, 13 ref

015805   Theresita Shanthi N;Selvarajan P;Mahadevan C K (NO, Dr. Sivanthi Aditanar College of Education, Tiruchendur-628 216) : Triglycine sulfate (TGS) crystals doped with sodium bromide (NaBr) grown by solution method. Indian J Sci Technol 2009, 2(3), 49-52.

Triglycine sulfate (TGS) crystals, with or without sodium bromide (NaBr) doping, were grown from aqueous solutions by slow evaporation method. The structural characterization was carried out by single crystal XRD method and found that all the grown crystals crystallize in monoclinic structure. The pure and NaBrdoped TGS crystals were also subjected to microhardness, dielectric studies, measurement of density and atomic absorption spectroscopic studies.

4 illus, 2 tables, 14 ref

015804   Steiner MR A (NO, Hahn-Meitner-Institute, Berlin, Email: steiner@hmi.de) : Perspectives of extreme sample environment in neutron scattering and consequences for instrumentation. Pramana J Phys 2008, 71(5), 893.

Because neutrons can penetrate bulky pieces of matter, increasingly complex sample environment is requested by the users of neutron beams. This corresponds to the ever-growing complexity of the scientific problems addressed by neutron scatterers. Until now such requirements could be satisfied by sample environment, which could be added to the instruments without major modifications. Now it becomes evident, that for certain applications further progress is possible only by bringing the neutrons to the sample environment instead of bringing the sample environment to the neutrons. As one of the first examples of this concept we will discuss the high field magnet (HFM), which Hahn-Meitner-Institute Berlin (HMI) and the National High Magnetic Field Laboratory Tallahassy (NHFML) are constructing jointly for BENSC at HMI. At BENSC the HMI has built in the meantime a dedicated instrument based on the TOF principle to be equipped with the HFM to enable experiments at fields up to 25 T.

015803   Steigenberger U (ISIS Facility, , , Email: U.E. Steogemnerger@rl.ac.ik) : ISIS facility - past achievements and future prospects. Pramana J Phys 2008, 71(5), 889.

The current status of the ISIS Pulsed Neutron and Muon Facility will be described covering operations and developments. Construction of a second target station was approved in 2004 including funding for the first seven neutron scattering instruments. Progress with the second target station project will be reviewed and updates on the design status of the seven 'Day One' instruments, as well as plans for the next phase of instrumentation will be presented.

015802   Sridevi D;Rajendran K V (Physics Dep, Presidency College, Chennai-600 093, Email: mspr1972@yahoo.com) : Synthesis and optical characteristics of ZnO nanocrystals. Bull Mater Sci 2009, 32(2), 165-8.

Zinc oxide nanomaterials with an average particle size of 20-30 nm are readily synthesized by the reaction of zinc acetate and oxalic acid under hydrothermal conditions. The samples are characterized by XRD, SEM, TEM, UV and photoluminescence (PL) studies. The average crystal size of the as prepared ZnO nanopowder is determined by XRD and the values are in good agreement with the TEM analysis. UV absorption spectra revealed the absorption at wavelength < 370 nm indicating the smaller size of ZnO nanoparticles. The quality and purity of ZnO nanomaterial crystalline samples are confirmed by photoluminescence spectra.

6 illus, 2 tables, 16 ref

015801   Siruguri V;Babu P D;Gupta M;Pimpale A V;Goyal P S (UGC-DAE Consortium for Scientific Research, Mumbai Centre R-5 Shed, Bhabba Atomic Research Centre, Mumbai-400 085, Email: siruguri@csr.ernet.in) : High resolution powder diffractometer using focusing optics. Pramana J Phys 2008, 71(5), 1197-1202.

Describes the design, construction and performance of a new high resolution neutron powder diffractometer that has been installed at the Dhruva reactor, Trombay, India. The instrument employs novel design concepts like the use of bent, perfect crystal monochromator and open beam geometry, enabling the use of smaller samples. The resolution curve of the instrument was found to have little variation over a wide angular region and a Δd/d ~ 0.3% has been achieved. The instrument provides sample environment of very low temperatures and high magnetic fields using a 7 Tesla cryogen-free superconducting magnet with a VTI having a temperature range of 1.5-320 K. The special sample environment and high resolution make this neutron powder diffractometer a very powerful facility for studying magnetic properties of materials.

3 illus, 8 ref

015800   Singh S;Poswal A K;Ghosh S K;Basu S (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: surendra@barc.gov.in) : Scatering length density profile of Ni film under controlled corosion: a study in neuttron reflectometry. Pramana J Phys 2008, 71(5), 1097-1101.

Reports the density depth profile of an as-deposited Ni film and density profile for the same film after controlled electrochemical corrosion by chloride ions, measured by unpolarized neutron reflectometry. The neutron reflectometry measurement of the film after corrosion shows density degradation along the thickness of the film. The density profile as a function of depth, maps the growth of pitting and void networks due to corrosion. The profile after corrosion shows an interesting peaking nature.

3 illus, 5 ref

015799   Singh S;Basu S;Gupta M (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: surendra@barc.gov.in) : Magnetic depth profiling of Fe/Au multilayer using neutron reflectometry. Pramana J Phys 2008, 71(5), 1103-7.

Presents unpolarized and polarized neutron reflectometry data on Fe/Au multilayer sample for characterizing the layer structure and magnetic moment density profile. Fe/Au multilayer shows strong spin-dependent scattering at interfaces, making it a prospective GMR material. Fe/Au multilayer with bilayer thickness of 130 Angstrom was grown on Si substrate by RF magnetron sputtering technique. Unpolarized neutron reflectivity measurement yields nuclear scattering length density profile. The magnetic scattering length density profile has been obtained from polarized neutron reflectivity measurements.

3 illus, 1 table, 8 ref

015798   Singh S;Basu S;Bhatt P (Solid State Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: surendra@barc.gov.in) : Structure and magnetism of Ni/Ti multilayers on annealing. Pramana J Phys 2008, 71(5), 1091-5.

Neutron reflectometry study has been carried out in unpolarized (NR) and polarized (PNR) mode to understand the structure and magnetic properties of alloy formation at the interfaces of Ni/Ti multilayers on annealing. The PNR data from annealed sample shows a noticeable change with respect to the as-deposited sample. These changes are: a prominent shift of the multilayer Bragg peak to a higher angle and a decrease in the intensity of the Bragg peak. The PNR data from annealed sample revealed the formation of magnetically dead alloy layers at the interfaces. Changes in roughness parameters of the interfaces on annealing were also observed in the PNR data.

3 illus, 9 ref

015797   Singh R S;Bhushan S (Physics Dep, Pt. Ravishankar Shukla University, Raipur-492 010, Email: rss.bhilai@gmail.com ) : Structural and optical properties of chemically deposited CD (S-Se): CdCl₂, Sm films. Bull Mater Sci 2009, 32(2), 125-33.

Results of SEM and XRD studies, optical absorption and photoluminescence (PL) emission spectra and photoconductivity (PC), rise and decay studies are reported for Cd(S-Se): CdCl₂, Sm films prepared by chemical deposition method on glass substrates at 60°C in a water bath. SEM studies show ball-type structures along with voids which are related to layered growth. XRD studies show prominent diffraction lines of CdS and CdSe along with some peaks of CdCl₂ and impurity Sm. The values of strain (ε), grain size (D) and dislocation density (δ) are evaluated from XRD studies and the nature of crystallinity of the films are discussed. Optical absorption spectra also show the presence of Sm in the lattice. From the results of optical absorption spectra, the band gaps are determined. PL emission spectra of Cd(S-Se) consist of two peaks which are related to the edge emission of CdS and CdSe involving excitons. In Sm-doped emissions corresponding to transitions ^{4G_5/2 to 6 H_5/22, 6 H_7/2 and 6 H _9/2 are observed. Sufficiently high photo current (I_pc) to dark current (I_dc) ratios with a maximum value of the order of 106 are also obtained in some special cases. This high photosensitization is related to increase in mobility and life time of carriers due to photo excitation.}

10 illus, 4 tables, 28 ref

015796   Singh P S;Aswal V K (RO Membrane Div, , Central Salt and Marine Chemicals Research Institute (CSIR), Email: puyam@csmcri.org) : Probing polymer nanocomposite morphology by small angle neutron scattering. Pramana J Phys 2008, 71(5), 947-52.

Polyamide nanocomposite films were prepared from nanometer-sized silica particles having particle radius of gyration (R_g) of about 66 Angstrom and trimesoyl chloride-m-phenylene diamine-based polyamides having macromolecular units of about 100-140 Angstrom. The nanoscale morphology of the samples was characterized using small angle neutron scattering (SANS). SANS reveals that silica nanoparticles interact well with the polyamide units only at limited silica loading.

2 illus, 6 ref

015795   Singh M (Physics Dep, Govt. P.G. College, Bageshwar-263 642, Email: dmpse@rediffmail.com) : Anisotropy in supercurrent density in layered cuprate superconductors. Ultra Scient phys Sci 2009, 21(2), 245-52.

Due to layered structure, the electronic conduction in high-Tc cuprate superconductors is highly anisotropic. Therefore, in the present work, we have made an attempt to study the anisotropy in supercurrent density in layered cuprate superconductors likeYBa₂Cu₃O_6+x. We have considered tight binding bilayered Hubbard Hamiltonian. The situation considered here for the bilayered cuprates is similar to a SIS junction. Using Green function technique, we have got the expressions for superconducting order parameters, carrier density and supercurrent densities. The numerical analysis shows that the anisotropy in supercurrent density depends on the temperature and various other microscopic parameters of the model Hamiltonian. The anisotropy in supercurrent density increases with temperature and diverges as system reaches towards the superconducting transition temperature. On increasing the carrier density within the plane, the anisotropy in supercurrent density decreases because around optimal doping region, bilayer system(YBaCuO) behaves like almost isotropic three dimensional superconductors. On increasing the interlayer attractive interaction, the anisotropy in supercurrent density decreases. It is also shown that when interlayer attractive interaction (W) is just equal to the intralayer pairing interaction (U), the anisotropy in supercurrent density vanishes i.e. the bilayer Quasi-2D system becomes almost isotropic(three dimensional) in supercurrent flow in the superconducting state. We have shown, using tight binding bilayer Hubbard model within BCS meanfield formalism, that the anisotropy in supercurrent density depend on various microscopic intra and interlayer interactions as well as on the thermodynamics of superconducting order parameter in an essential way. Finally we have compared our theoretical results of anisotropy in supercurrent density with the existing experimental findings in bilayered cuprate superconductors.

3 illus, 26 ref

015794   Singh K B;Mukesh Kumar (Polytechnic K B, , Darbhanga, Bihar, Email: kbsphysics@yahoo.co.in) : Optical binding between dielectric particles through millimeter wave propagation. Ultra Scient phys Sci 2009, 21(2), 269-74.

That the optical binding between dielectric particles through ~ millimeter wave propagation at 30-50 GHz having bulk mixture of two dielectric bodies at different sizes. We suppose the dielectric particles having dimensionless than the wavelength of the interacting light under millimeter wave propagation. An optimum increase in binding energy was noted for all cases. This study further indicates the suitability of this technique for construction of two or e-dimensional arrangement of objects. The observed dependence of the separation of optically bond particles on millimeter wave propagation is in good agreement with earliest theoretical predictions.

2 illus, 7 ref

015793   Shinde S;Jha P K (Nirma University of Sciences and Technology, , S-C Highway, Ahmedabad-382 481, Email: pkj@bhavuni.edu) : Lattice dynamics of ferromagnetic superconductor UGe₂. Pramana J Phys 2008, 71(5), 1147-51.

Reports the lattice dynamical study of the UGe₂ using a lattice dynamical model theory based on pairwise interactions under the framework of the shell model. The calculated phonon dispersion curves and phonon density of states are in good agreement with the measured data.

1 illus, 2 tables, 14 ref

015792   Sharma Y;Sharma N;Subba Rao G V;Chowdari B V R (Physics Dep, National University of Singapore, 117542, Singapore, Email: phychowd@nus.edu.sg) : Li-storage and cycling properteis of spinel, CdFe₂O₄, as an anode for lithium ion batteries. Bull Mater Sci 2009, 32(3), 295-304.

Cadmium ferrite, CdFe₂O₄, is synthesized by urea combustion method followed by calcination at 900°C and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) techniques. The Li-storage and cycling behaviour are examined by galvanostatic cycling, cyclic voltammetry (CV) and impedance spectroscopy in the voltage range, 0.005-3.0 V vs Li at room temperature. CdFe₂O₄ shows a first cycle reversible capacity of 870 (± 10) mAhg^{-1 at 0.07C-rate, but the capacity degrades at 4 mAhg-1 per cycle and retains only 680 (± 10) mAhg-1 after 50 cycles. Heat-treated electrode of CdFe₂O₄ (300°C; 12 h, Ar) shows a significantly improved cycling performance under the above cycling conditions and a stable capacity of 810 (± 10) mAhg-1 corresponding to 8.7 moles of Li per mole of CdFe₂O₄ (vs theoretical, 90 moles of Li) is maintained up to 60 cycles, with a coulombic efficiency, 96-98%. Rate capability of heat-treated CdFe₂O₄ is also good: reversible capacities of 650 (± 10) and 450 (± 10) mAhg-1 at 0.5 C and 1.4 C (1 C = 840 mAg-1) are observed, respectively. The reasons for the improved cycling performance are discussed. From the CV data in 2-15 cycles, the average discharge potential is measured to be ~0.9 V, whereas the charge potential is ~2.1 V. Based on the galvanostatic and CV data, ex situ-XRD, -TEM and -SAED studies, a reaction mechanism is proposed. The impedance parameters as a function of voltage during the 1st cycle have been evaluated and interpreted.}

7 illus, 40 ref