010456   Bhide M K;Seshagiri T K;Ojha S;Godbole S V (Radiochemistry Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: giritks@gmail.com) : Photoluminescence, thermally stimulated luminescence and electron paramagnetic resonance studies of U<. Bull Mater Sci 2014, 37(1), 123-6.

U^{6+ doped BaSO₄ samples were synthesized by precipitation route. PL, TL and EPR investigations of γ and self a irradiated samples were carried out. PL spectra of these samples give structured broad band peaking around 518 nm with five vibronic bands centred around 498.4, 516.0, 533.7, 554.0 and 575.1 nm, respectively and the average frequency of symmetric stretching of O=U=O in the ground electronic state was found to be 674 cm-1. Trap level spectroscopic studies of U doped BaSO₄ give glow peaks at 411, 488 and 512 K, respectively and their spectral characteristics are typical of UO₂2+ emission. EPR studies of γ -irradiated U6+:BaSO₄ sample have shown the presence of sulphoxy centred radicals like SO₄- and SO₃- in addition to OH+, O₃- and SH2-. TSL peaks at 411 and 488 K were correlated with thermal destruction of SO₄- and SO₃- radicals.}

5 illus, 22 ref

010455   Benabdeslem M;Bouasla A;Benslim N;Bechiri L; Mehdaoui S;Aissaoui O;Djekoun A;Fromm M;Portier X (Laboratoire LESIMS, Universite d' Annaba, BP12, 23200 Sidi Amar, Algerie, Framce, Email: nemandes@yahoo.fr) : Zn incorporation in CuInSe2: Particle size and strain effects on microstructural and electrical properties. Bull Mater Sci 2014, 37(3), 469-72.

Incorporation of the doping element Zn in the temperature range (550-700°C) and the impact on structural and electrical properties of CuInSe₂ material are investigated. X-ray diffraction patterns showed the chalcopyrite nature of the pure and doped CuInSe₂ and revealed that diffusion temperature governs particle size as well as tensile strain. The calculated lattice parameters and cell volumes revealed that Zn diffuses in CuInSe₂ by substitution on Cu sites. Electrical properties of the material have been investigated using a contact-less technique based on high frequency microwave (HF). It is found that Zn atoms influence the defect equilibrium resulting in the conversion of the conduction type. The conductivity of the samples has been found increasing as the diffusion temperature increases.

5 illus, 1 table, 18 ref

010454   Banerjee S;Hajra P;Datta A;Bhaumik A;Mykanth Reddy Mada;Bandyopadhyay S;Chakravorty D (Indian Association for the Cultivation of Science, , Kolkata-700 032, Email: mlsdc@iacs.res.in ) : Magnetodielectric effect in Ni_0ù5Zn_0ù5Fe₂O₄-BaTiO₃ nanocomposites. Bull Mater Sci 2014, 37(3), 497-504.

Composites comprising of nanoparticles of Ni_0ù5Zn_0ù5Fe₂O₄ (NZF) and BaTiO₃ (BT), respectively were synthesized by a chemical method. The particles had diameters in the range of 15-31 nm. NZF was prepared by a coprecipitation technique. This was soaked in a sol containing BT. Compositions synthesized were xNZF-(1 - x) BT, where x = 0ù7, 0ù5 and 0ù3, respectively. The composites showed ferromagnetic hysteresis loops due to NZF phase. The analysis of coercivity variation as a function of temperature gave blocking temperatures in the range of 306-384 K depending on the diameter of the ferrite nanoparticles. This implied that superparamagnetic interactions are above these temperatures. The nanocomposites also exhibited ferroelectric behaviour arising due to the presence of BT. The remanent polarization of the samples was small. This was adduced to the nanosize of BT. The specimens showed magneto-dielectric (MD) effect in the magnetic field range 0-0ù7 Tesla. The MD parameter measured at the maximum magnetic field was around 2%. This was one order of magnitude higher than that reported so far in similar composite systems. This was explained on the basis of a two-phase inhomogeneous medium model with an interface between them, the phases possessing drastically different electrical conductivities

8 illus, 4 tables, 44 ref

010453   Arifin A;Hatta A M;Muntini M S;Rubiyanto A (Physics Dep, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia, Email: arifinpide@gmail.com) : Bent of plastic optical fiber with structural imperfections for displacement sensor. Indian J pure appl Phys 2014, 52(8), 520-4.

An arrangement of bending and structural imperfection in a plastic optical fiber (POF) for a displacement measurement system has been investigated. An evaluation on the output power of the POF caused by the displacement which induced the bending alongside the POF's structural imperfection was determined. The experimental measurement clearly revealed that the sensor exhibited an increasing sensitivity and better resolution for the shorter sensor and more structural imperfection. Additionally, the sensor can be applied for measuring the displacement in the range of 15 mm by means of infrared LED. The maximum sensitivity of 0.2401 μW/mm and the finest resolution of 4.2 μm were obtained by the sensor length of 6 cm with 3 structural imperfections. The proposed displacement sensor offers a very simple design, high sensitivity and resolution, low fabrication cost and good suitability for large displacement measurements.

4 illus, 1 table, 13 ref

009487   Upadhyay S (Physics Dep, Institute of Technology, Banaras Hindu Univ, Varanasi-221 005, Email: supadhyay.app@itbhu.ac.in) : High temperature impedance spectroscopy of barium stannate, BaSnO₃. Bull Mater Sci 2013, 36(6), 1019-36.

Poly crystalline powder of BaSnO₃ was prepared at 1300 °C using a high-temperature solid-state reaction technique. X-ray diffraction analysis indicated the formation of a single-phase cubic structure with lattice parameter: a = (4.1158 ± 0.0003) Å. The synthesized powder was characterized using X-ray diffraction (XRD) scanning electron micrographs, energy dispersive X-ray analysis, differential thermal analysis, thermogravimetric analysis and Fourier transform infrared techniques. Electrical properties were studied using a.c. impedance spec-troscopy technique in the temperature range of 50-650 °C and frequency range of 10 Hz-13 MHz. The complex impedance plots at temperature ≥300 °C show that total impedance is due to the contributions of grains, grain boundaries and electrode. Resistance of these contributions has been determined. Variation of these resistances with temperature shows the presence of two different regions with different slopes. The nature of variation for the above three resistances, in both the temperature regions confirms that conducting species (phases) responsible for grain, grain boundaries and electrode are the same. Based on the value of activation energy, it is proposed that conduction via hopping of doubly ionized oxygen vacancies (V_o**) is taking place in the temperature region of 300-450 °C, whereas in the temperature region of 450-650 °C, hopping of proton, i.e. OH* ions occurs.

12 illus, 5 tables, 31 ref

009486   Swamy D T;Ephraim Babu K;Veeraiah V (Physics Dep, Gitam Institute of Technology, Gitam Univ, Visakhapatnam-530 045, Email: swamydts@yahoo.co.in) : Evidence for high ionic conductivity in lithium - lanthanum titanate, Li_0.29La_0.57TiO₃. Bull Mater Sci 2013, 36(6), 1115-19.

Lithium-lanthanum titanate, Li_0.29La_0.57TiO₃, is prepared by solid-state reaction method and it is furnace-cooled to room temperature. X-ray diffraction results indicated that the compound has tetragonal perovskite-like structure and the lattice parameters are determined as a = 3.8714 Å and c = 7.7370 Å. The average grain size is found to be 5 μm from SEM micrograph. The analysis of FTIR and Raman spectra of the sample supported tetragonal structure inferred from XRD data. The impedance spectrum of the sample is separated into bulk and grain boundary parts by analysing the impedance data. The high bulk ionic conductivity is reported as 1.12 x 10^{-3 S cm-1 at room temperature. D.C. conductivity measurements indicate that the compound is a good ionic conductor.}

9 illus, 22 ref

009485   Sorot N;Goyal M;Gupta B R K (Physics Dep, IAH, GLA Univ, Mathura, Uttar Pradesh) : Temperature dependence of thermal expansivity of carbon fullerene and 20-nm nickel nanocrystal. Nano Vision 2013, 3(2), 62-9.

Authors have determined the thermoelastic properties such as volume thermal expansion coefficient, volume expansion and bulk modulus for fullerene(C₆₀) and 20-nm nickel nanocrystal using a simple method as suggested by Zheng-Hua Fang [Solid-state Sciences, 10 (2008), 950]. The calculated values of thermal expansivity and volume thermal expansion are compared to the available data based on molecular simulation method and the results of thermal expansivity obtained for 20-nm nickel are compared to the available experimental data. A good agreement has been obtained between the theoretically calculated results and available experimental data.

6 illus, 22 ref

009484   Singh R (Physics Education, History and Philosophy of Science, Oldenburg Univ, Germany, Email: rajinder_singh_dr@yahoo.de) : Wright brothers and the nobel prize. Curr Sci 2013, 104(11), 1461-1.

6 ref

009483   Sharma R C;Deepak Kumar;Bhardwaj N;Maini A K (Laser Science and Technology, Centre, Defence Research and Development Organization, Metcalfe House, Delhi-110 054, Email: rameshsharma@lastec.drdo.in) : Quartz enhanced laser photoacoustic sensors for remote sensing. Curr Sci 2013, 104(11), 1548-51.

Here it is reported an active spectral sensor for chlorophyll detection based on quartz crystal tuning fork detector. The sensors use modulated diode laser radiations that can be differentiated from ambient background radiations by the detector. Experimentally, electrical and optical parameters of quartz crystal tuning fork detector (QCTF) were studied. Linear dependence of optical power to the generated electrical signals of QCTF detector was derived by measurements at different optical powers and wavelengths. Reports here Quartz Enhanced Laser Photoacoustic signal of chlorophyll traces dissolved in water and adsorbed on surfaces, using 532 nm and 635 nm wavelength lasers from a standoff distance of up to 25 m. With the availability of high-power tunable diode laser, the technique offers a wide range of applicability for point and standoff sensing.

3 illus, 14 ref

009482   Roy R;Guha A;De B K;Choudhury A (Physics Dep, Tripura Univ, Suryamaninagar-799 022) : VLF atmospherics during the tropical cyclone "AILA" and several monsoon period thunderstorms over North East India. Mausam 2013, 64(1), 81-8.

Present work reports the characteristic variations in VLF atmospherics or sferics at four discrete frequencies recorded at the Department of Physics, Tripura University, during the period from April 2009 to October 2009. Data from 76 active thunder days over North-East India is considered for the present investigation. Results show several types of features in the variation of sferics during the monsoon period. These are termed as gradual fall gradual rise (GFGR), gradual rise sudden fall (GRSF), gradual rise gradual fall (GRGF), gradual fall sudden rise (GFSR), sudden rise gradual fall (SRGF), sudden rise sudden fall (SRSF), sudden fall sudden rise (SFSR), sudden fall gradual rise (SFGR) and spiky. During the Monsoon thunder active days, amongst all the patterns, GRGF occurred in most of the cases in all frequencies (average occurrence rate around 37% in each frequency). During our observational period, a severe tropical cyclonic storm named "AILA" (RSMC Designation BOB02, JTWC Designation 02B) occurred over the Bay of Bengal during 23-26 May 2009. Among several characteristic features during normal Monsoon period, SRSF (average occurrence rate around 86% in each frequency) dominated the sferics on the 25 May, 2009, when the cyclone struck the coastal areas of the Bay of Bengal. The sferics of that day has been analyzed critically with respect to discrete frequency distribution of rise rate and fall rate of the intensity of the sferics. A comparison is made for all the patterns for the Monsoon days and the AILA cyclone active day. Our findings show substantial difference in the microstructure of clouds producing severe cyclonic storms like AILA and other thunderstorms during Monsoon seasons over North-East India. The possible interpretation of the observed variations in sferics is explained on the basis of the electrical activity that occurs inside a thunder-cloud especially during cyclonic activity.

5 illus, 18 ref

009481   Rasmussen R O;Donavan P R (NO, , ) : What causes road noise?. Sci Cult 2014, 80(5-6), 165-7.

2 illus

009480   Rani A;Bhatt S C;Shivagan D D;Singh Y P (CSIR-National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi-110 012, Email: ypsingh@nplindia.org) : Characterization and evaluation of thermal stability and uniformity of a liquid temperature bath containing a toluene heat pipe. MAPAN 2013, 28(1), 41-50.

The objective of this paper is to present a study carried out for the evaluation of the thermal stability and uniformity of a heat pipe modified water chamber. It can serve as a standard procedure that can be applicable to any other equilibrium thermal source used with water or any liquidus like medium for temperature distribution. These sources are utilized for comparison of high precision thermometers or sensor based temperature instruments having resolution of the order of 0.01 °C. In the present work a temperature water bath has been modified with a heat pipe cylindrical chamber provided with a forced circulation of fluid from the temperature controlled circulator. A standard platinum resistance thermometer with high precision resistance bridge was used for temperature measurement in the chamber at different locations horizontally and vertically as well. The thermal stability of this heat pipe modified chamber was evaluated to be ±0.006 to ±0.022 °C and uniformity to be ±0.015 to ±0.031 °C at different measured temperatures in the range from 5 to 90 °C. The uncertainty components due to these parameters have also been evaluated and reported in the paper.

8 illus, 7 tables, 17 ref

009479   Rana S K;Sharma P K (School of Basic and Applied Sciences, Career Point Univ, Hamirpur, Himachal Pradesh, Email: sanjeevrananit@gmail.com) : Application of homotopy perturbation method to study wave propagation in transversely isotropic thermoelastic three dimensional plate. Asian J Adv Basic Sci 2015, 3(2), 30-9.

Wave motion in an infinite transversely isotropic, thermoelastic plate in the context of conventional coupled thermoelasticity (CT), Lord-Shulman (LS) and Green-Lindsay (GL) theories of generalized thermoelasticity has been studied by using Homotopy perturbation method (HPM). The expressions for displacement components and temperature are derived. Finally, the numerical solution is carried out for transversely isotropic plate. The dispersion curves of displacements with thickness and time are presented graphically for coupled and generalized theories of thermoelasticity.

9 ref

009478   Purushotham E;Gopi Krishna N (Physics Dep, Kakatiya Univ, Warangal-506 009, Email: psm45456@gmail.com) : X-ray determination of crystallite size and effect of lattice strain on debye-waller factors of platinum nano powders. Bull Mater Sci 2013, 36(6), 973-6.

In the present study, nano platinum particles were produced by ball milling process. The lattice strains in platinum (Pt) powders produced by milling have been analysed by X-ray powder diffraction. The lattice strain (ε) and Debye-Waller factor (B) are determined from the half-widths and integrated intensities of the Bragg reflections. In Pt, the Debye-Waller factor is found to increase with lattice strain. From the correlation between the strain and effective Debye-Waller factor, the Debye-Waller factors for zero strain have been estimated for Pt. The variation of energy of vacancy formation as a function of lattice strain has been studied.

2 illus, 1 table, 17 ref

009477   Mandal G;Kumar A;Sharma D C;Kumar H (NO, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012, Email: goutam@nplindia.org) : Comparative analysis of different air density equations. MAPAN 2013, 28(1), 51-62.

In general mass measurements are carried out in air and that's why air buoyancy correction plays a major role in mass measurements and it is totally dependent on density of air of the laboratory during the measurement. The density of air is calculated from temperature, relative humidity, air pressure, concentration of CO₂ monitored (for C1PM formula only) in the laboratory rather direct determination and for calculation of density of air, CIPM-2007 formula is recognized as most accurate formula. Since CIPM formula is very complicated formula and it is not required for less accurate measurements, different National Metrology Institutes have derived simple equations to calculate air density and those are known as approximation formulas. We had gone through a comparative analysis among different formulas of density of air to evaluate which approximation formula is most accurate compare to CIPM-2007 formula.

1 illus, 4 tables, 9 ref

009476   Logeswaran T;Parthibavarman M;Arunkumar T (Physics Dep, Nanotechnology Laboratory, Sri Ramakrishna Mission Vidhalaya College o, Coimbatore, Tamil Nadu) : Microwave assisted technique for synthesizing ZnCdO nanopowder humidity sensor. Nano Vision 2013, 3(2), 44-52.

Now a days nano sensors place a vital role in sensing of smell less toxic gases which are polluting the environment. Its active role paved a path in protection of environments from the hazards. An attempt is made by using ZnCdO nanopowder humidity sensor. ZnCdO nanoparticles have been prepared by using a simple household microwave irradiation with an operating frequency of 2.45 GHZ. This technique permits us to produce gram quantity of inhomogenous nanoparticle in just 10min. The variation of conductivity in ZnCdO nanopowder ensures to; analyze the sensor behavior easily and humidity controlled electronic devices. The samples were further subjected to photoluminescence (PL), Scanning electron microscope (SEM) studies. The humidity variations are observed inside the solar still along with the water temperature and air temperature. The performance efficiency of the sensor is studied and reported.

8 illus, 21 ref

009475   Logeswaran T;Parthibavarman M (Physics Dep, Nanotechnology laboratory, Sri Ramakrishna Mission Vidhalaya College, Coimbatore, Tamil Nadu) : Synthesis of albumen (egg white) assisted SnO₂ nanoparticles by microwave irradiation method. Nano Vision 2013, 3(2), 54-60.

The Tin dioxide nanoparticle is synthesized in the microwave irradiation method with albumen (egg white). This method is simple and cost effect synthesis of SnO₂ nanoparticles. The egg white foam was assisted to increase the reaction rate and this method helps to attain the particle size in the range 75-80nm. The result from X-ray diffraction patterns confirmed the formation of nano crystalline phase with particle size range from 75nm to 80nm. The samples were further analyzed by using Fourier transform infrared spectroscopy (FT-IR), photoluminescence spectrum (PI), Transmission electron microscope (TEM) and resistivity measurement.

6 illus, 16 ref

009474   Koparan E T;Surdu A;Kizilkaya K;Sidorenko A; Yanmaz E (Physics Dep, Karadeniz Technical Univ, Trabzon 61080, Turkey, Email: etaylan20@gmail.com) : Pinning enhancement in MgB₂ superconducting thin films by magnetic nanoparticles of Fe₂O₃. Bull Mater Sci 2013, 36(6), 961-6.

MgB2 thin films were fabricated on r-plane Al₂O₃ (1102) substrates. First, deposition of boron was performed by rf magnetron sputtering on Al₂O₃ substrates and followed by a post-deposition annealing at 850 °C in magnesium vapour. In order to investigate the effect of Fe₂O₃ nanoparticles on the structural and magnetic properties of films, MgB2 films were coated with different concentrations of Fe₂O₃ nanoparticles by spin coating process. The magnetic field dependence of the critical current density J_c was calculated from the M-H loops and magnetic field dependence of the pinning force density, f_p(b), was investigated for the films containing different concentrations of Fe₂O₃ nanoparticles. The critical current densities, J_c, in 3T magnetic field at 5 K were found to be around 2.7 x 10^{4 A/cm2, 4.3 x 104 A/cm2,1.3 x 105 A/cm2 and 5.2 x 104 A/cm2 for films with concentrations of 0, 25, 50 and 100% Fe₂O₃, respectively. It was found that the films coated with Fe₂O₃ nanoparticles have significantly enhanced the critical current density. It can be noted that especially the films coated by Fe2O3 became stronger in the magnetic field and at higher temperatures. It was believed that coated films indicated the presence of artificial pinning centres created by Fe₂O₃ nanoparticles. The results of AFM indicate that surface roughness of the films significantly decreased with increase in concentration of coating material.}

8 illus, 2 tables, 18 ref

009473   Kikuchi T (NO, National Metrology Institute of Japan/AIST, 1-1-1, Umezono, Tsukuba 305-8563, Japan, Email: tsuneo.kikuchi@aist.go.jp) : Tentative uncertainty evaluation of thermal and mechanical indices used for medical ultrasound. MAPAN 2013, 28(1), 37-9.

Tentative estimations of uncertainties of thermal index (77) and mechanical index (Ml) are described. Recently, high power and high pressure ultrasound has become an important tool for increasing quality of medical ultrasound required in the diagnosis and treatments. Precise control of ultrasonic power or acoustic pressure is required to contain the hazards to the human body caused by high power and high acoustic pressure and frequency of ultrasound. Due to this reason, 77 and MI are very important parameters as indices, which denote the effects of ultrasonic power and acoustic pressure to human body. The uncertainties of TI and Ml are based on the measured quantities such as ultrasonic power, acoustic pressure and frequency. The uncertainties of these measured values are usually calculated by measurers. When 77 and MI are estimated, uncertainties of these indices also should be evaluated as same as other quantities for checking the validity of the values. Actually, these uncertainties have not been discussed. In this paper, relative expanded uncertainties of 77 and MI which include the uncertainty caused by the bandwidth are estimated.

3 illus, 6 ref

009472   Joseph D;Yadav A K;Jha S N;Bhattacharyya D (Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai-400 085, Email: dibyendu@barc.gov.in) : Chemical shift of Mn and Cr K-edges in X-ray absorption spectroscopy with synchrotron radiation. Bull Mater Sci 2013, 36(6), 1067-72.

Mn and Cr K X-ray absorption edges were measured in various compounds containing Mn in Mn^{2+, Mn3+ and Mn4 oxidation states and Cr in Cr3+ and Cr6+ oxidation states. Few compounds possess tetrahedral coordination in the 1st shell surrounding the cation while others possess octahedral coordination. Measurements have been carried out at the energy dispersive EXAFS beamline at INDUS-2 Synchrotron Radiation Source at Raja Ramanna Centre for Advanced Technology, Indore. Energy shifts of <126>8-16 eV were observed for Mn K edge in the Mn-compounds while a shift of 13-20 eV was observed for Cr K edge in Cr-compounds compared to values in elemental Mn and Cr, respectively. The different chemical shifts observed for compounds having the same oxidation state of the cation but different anions or ligands show the effect of different chemical environments surrounding the cations in determining their X-ray absorption edges in the above compounds. The above chemical effect has been quantitatively described by determining the effective charges on Mn and Cr cations in the above compounds.}

4 illus, 2 tables, 8 ref

009471   Ding Y H;Ren H M;Chang F H;Zhang P;Jiang Y (Institute of Rheology Mechanics, Xiangtan Univ, Xiangtan, China, Email: yhding@xtu.edu.cn) : Intrinsic structure and friction properties of graphene and graphene oxide nanosheets studied by scanning probe microscopy. Bull Mater Sci 2013, 36(6), 1073-7.

In this paper, atomic structure of single-layered graphene oxide (GO) and chemically reduced graphene oxide (CRGO) nanosheets was investigated using atomic force microscopy and scanning tunneling microscopy (AFM and STM). Furthermore, friction properties of the graphene and GO nanosheets were studied by frictional force microscopy (FFM). STM imaging provided direct evidence and the morphology was influenced by oxygen-containing groups and defects. The atomic scale structural disorder in a hexagonal two-dimensional network of carbon atoms changes the surface condition, which also caused the frictional property variations of the samples.

5 illus, 18 ref

009470   Bari R H;Patil P P;Patil S B;Bari A R (Physics Dep, G.D.M. Arts, K.R.N. Commerce and M.D. Science College, Jamner-424 206, Email: rameshbari24@yahoo.com) : Detection of H₂S gas at lower operating temperature using sprayed nanostructured In₂O₃ thin films. Bull Mater Sci 2013, 36(6), 967-72.

Nanostructured indium oxide (In₂O₃) thin films were prepared by spray pyrolysis (SP) technique. X-ray diffraction (XRD) was used to investigate the structural properties and field emission scanning electron microscopy (FESEM) was used to confirm surface morphology of In₂O₃ films. Measurement of electrical conductivity and gas sensing performance were conducted using static gas sensing system. Gas sensing performance was studied at different operating temperature in the range of 25-150 °C for the gas concentration of 500 ppm. The maximum sensitivity (S = 79%) to H₂S was found at lower temperature of 50 °C. The quick response (4 s) and fast recovery (8 s) are the main features of this film.

8 illus, 1 table, 11 ref

009469   Ahmad T;Khatoon S;Coolahan K (Chemistry Dep, Jamia Millia Islamia, New Delhi-110 025, Email: tahmad3@jmi.ac.in) : Optical, magnetic and structural characterization of Zn_1-xCo_xO nanoparticles synthesized by solvothermal method. Bull Mater Sci 2013, 36(6), 997-1004.

Nanoparticles of Co-doped ZnO with 3.8, 7.2 and 11.5 wt% were synthesized by solvothermal method through oxalate precursor route. X-ray diffraction studies showed the formation of hexagonal ZnO structure for x = 0.038, however, secondary phase of Co₃O₄ arises on increasing the Co content up to 11.5%. Transmission electron microscopic studies showed that particles are in the nano-metric regime and the grain size decreases on increasing the Co concentration. Optical reflectance measurements showed an energy bandgap, which decreases on increasing Co concentration. Specific surface area of these nanoparticles was found to be very high and comes out to be 97.6, 112.1 and 603.8 m^{2g-1, respectively. All the solid solutions showed paramagnetism with weak antiferromagnetic interactions. It is seen that the antiferromagnetic interaction increases on increasing Co concentration.}

11 illus, 22 ref

008536   Tiwari R;Tamrakar R K;Swamy N K;Dubey V (Applied Physics Dep, Bhilai Institute of Technology, (Seth Balkrishan Memorial), Raipur, Chhattisgah, Email: 31rati@gmail.com) : Mechanoluminescence properties of (Cd_0.95Zn_0.5)S mixed nanoparticles doped with silver. Ultra Scient phys Sci-Sect B 2014, 26(1), 1-6.

Mechanoluminescence behavior of (Cd_0.95Zn_0.5)S: Ag doped phosphor when load of 250 gm was dropped from 50 cm height for 2.5 Molar % concentrations of Ag ions has been studied. The particle size of (Cd_0.95Zn_0.5)S:Ag were calculated by Debye scherrer's formula and it was found to be 185 nm. Miller indices has also been calculated. (Cd_0.95Zn_0.5)S:Ag sample has been prepared by solid state method. The effects of UV-Exposure time on luminescence characteristics were investigated.

4 illus, 1 table, 23 ref

008535   Srivastava P;Singh K (Physics Dep, Faculty of Science, Banaras Hindu Univ, Varanasi-221 005, Email: kedarbhp@rediffmail.com) : Morphological evolution in single-crystalline Bi₂Te₃ nanoparticles, nanosheets and nanotubes with different synthesis temperatures. Bull Mater Sci 2013, 36(5), 765-70.

General surfactant-assisted wet chemical route has been developed for the synthesis of a variety of bismuth telluride (Bi₂Te₃) single-crystalline nanostructures with varied morphologies at different temperatures in which hydrazine hydrate plays as an important solvent. Bi₂Te₃ sheet grown nanoparticles, nanosheets and nano-tubes have been synthesized by a simplest wet chemical route at 50, 70 and 100 °C within 4 h. Bi₂Te₃ sheet grown nanoparticles are obtained in agglomerate state and they are found with many wrinkles. Various types of Bi₂Te₃ nanotubes are also found which are tapered with one end open and the other closed. X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) pattern and energy dispersive X-ray (EDX) spectroscopy were employed to characterize the powder product. It is found that all nanoparticles, nanosheets and nanotubes are well-crystallized nanocrystals and morphologies of the powder products are greatly affected by different synthesis temperatures. The formation mechanisms of bismuth telluride nanostructures are also discussed.

5 illus, 38 ref

008534   Srivastava A;Lal V (Mathematics Dep, K.N. Govt. P.G. College, S.R.N. Bhadohi) : Unsteady velocity field of MHD couette flow. Ultra Scient phys Sci-Sect B 2014, 26(1), 7-12.

In this paper we have considered the oscillatory flow performing small harmonic oscillation in a channel of gap h. The analysis is based on Ishigaki work in which, he has assumed the stream unsteady flow with its conjugate complex part. We obtained the amplitude of the fluctuating velocity gradients its variation with respect to transfer magnetic field. An exact analysis of oscillatory MHD Couette flow has been performed by using series solution method. Numerical calculations are made for phase angle and shearing stress of the unsteady MHD flow in a horizontal channel for various values of Hartman number.

6 illus, 6 tables, 16 ref

008533   Kungumadevi L;Sathyamoorthy R (Physics PG and Research Dep, Kongunadu Arts and Science College, Coimbatore-641 029, Email: rsathya1959@gmail.com) : Synthesis of PbTe nanocubes, worm-like structures and nanoparticles by simple thermal evaporation metod. Bull Mater Sci 2013, 36(5), 771-8.

Nanocrystalline PbTe thin films are prepared by thermal evaporation on glass substrates. The investigations of X-ray diffractograms have shown that the structure of film is found to possess stable face centred cubic (fcc) phase in which the grams predominantly grow in the direction of (200) plane. The grain size of the films is within the range of 27-43 nm. Morphologies like assembly of nanoparticles, worm-like structures and nanocubes were prepared by tuning the film thickness. Electrical resistivity is measured using four-probe technique and its thickness dependence has been analysed on the basis of 'effective mean free path model'. A change in conductivity from n-type to p-type is observed due to the increase of migration of tellurium vacancies in the films with temperature. Bandgap energy of the PbTe nanocrystalline thin films suffered a large blue shift of about 1.299 eV due to quantum confinement of charge carriers. The nanocrystalline PbTe thin films of different morphologies such as nanoparticles, worm-like and nanocubes have the optical bandgap energies of 1.61,1.23 and 1.01 eV, respectively. Photoconductivity measurement shows that the prepared nanocrystalline PbTe thin films of different morphology exhibits good response. This structure induced change in optical properties may have potential applications in optoelectronics devices.

12 illus, 25 ref

008532   Diwan B D;Singh A;Kurrey M S (Basic Sciences Dep, Dr C.V. Raman Univ, Bilaspur-495 001, Email: bddiwan@gmail.com) : Effective band gap in semiconductor nano-solid. Invertis J renewable Energy 2014, 4(3), 132-5.

Study was done if the size dependence effective band gap of semiconductor nano-solid. The band gap is one of the most significant electronic parameters of semiconductor material. The band gap of semiconductor dependents on the temperature, pressure, composition, number of atoms as well as size of the solid. When semiconductor solids are prepared in the form of nano-metric level, their small particle size gives rise to quantum confinement and the energy bands are split into discrete levels. It is found that the effective band gap decreases with increasing the size (number of atoms and diameter) of nano-solid. Another conclusion is that the energy band gap of semiconductor tend to decrease with increasing temperature and hence atomic vibration increases.

2 illus, 1 table, 15 ref

008531   Dash B N;Mallick P;Dash P;Biswal R;Prakash Jai;Tripathi A;Kanjilal D;Mishra N C (Physics Dep, Salipur College, Salipur-754 103) : Swift heavy ion irradiation induced modification of structure and surface morphology of BiFeO₃ thin film. Bull Mater Sci 2013, 36(5), 813-18.

BiFeO₃ (BFO) thin films of thickness about 800 nm deposited on Si (100) substrates by sol-gel spin coating method were irradiated by 200 MeV Ag ions. Modification of structure and surface morphology of the films under irradiation was studied using glancing incidence X-ray diffraction (GIXRD) and atomic force microscope (AFM). Fluence dependence of GIXRD peak intensity indicated formation of 10 nm diameter cylindrical amorphous columns in crystalline BFO due to 200 MeV Ag ion irradiation. AFM analysis indicated that the pristine film consists of agglomerated grains with diffuse grain boundary. Irradiation led to reduced agglomeration of the grains with the formation of sharper grain boundaries. The rms roughness (σ_rms) estimated from AFM analysis increased from 6.2 in pristine film to 12.7 nm when the film irradiated at a fluence of 1 x 10^{11 ions cm-2. Further irradiation led to decrease of σ_rms which finally saturated at a value of 7-8 nm at high ion fluences. The power spectral density analysis indicated that the evolution of surface morphology of the pristine film is governed by the combined effect of evaporation condensation and volume diffusion processes. Swift heavy ion irradiation seems to increase the dominance of volume diffusion in controlling surface morphology of the film at high ion fluences.}

5 illus, 1 table, 35 ref

008530   Dalawai S P;Shinde T J;Gadkari A B;Vasambekar P N (Electronics Dep, Shivaji Univ, Kolhapur-416 004, Email: sanjeevdalawai@gmail.com) : Structural properties of Cd-Co ferrites. Bull Mater Sci 2013, 36(5), 919-22.

Ferrite samples with composition, Cd_xCo_1-xFe₂O₄ (x = 0.80, 0.85, 0.90, 0.95 and 1.0), were prepared by standard ceramic method and characterized by XRD, IR and SEM techniques. X-ray analysis confirms the formation of single phase cubic spinel structure. Lattice constant and grain size of the samples increase with increase in cadmium content. Bond length (A-O) and ionic radii (R_A) on A-sites increase, whereas bond length (B-O) and ionic radii (R_B) on B-site decrease. The crystallite sites of the samples lie in the range of 29.1-42.8 nm. IR study shows two absorption bands around 400 cm^{-1 and 600 cm-1 corresponding to tetrahedral and octahedral sites, respectively.}

4 illus, 1 table, 11 ref

008529   Dakhel A A (Physics Dep, College of Science, Bahrain Univ, P.O. Box 32038, Bahrain, Kingdom of Bahrain) : High mobility carriers in Ni-doped CdO films. Bull Mater Sci 2013, 36(5), 819-25.

Cadmium oxide (CdO) doped with different amounts of nickel ion thin films have been prepared on silicon and glass substrates by vacuum evaporation technique. The effects of nickel doping on the structural, electrical, optical and optoelectronic properties of the host CdO films were systematically studied. The sample elemental composition was determined by the X-ray fluorescence spectroscopy method. The X-ray diffraction method was used to study the crystalline structure of the samples. It shows that some of Ni^{3+ ions occupy mainly locations when in interstitial positions and Cd2+ -ion vacancies of CdO lattice. The bandgap of Ni-doped CdO suffers narrowing till 10-12% compared to undoped CdO. Such bandgap narrowing was studied within the framework of the available models. The electrical behaviours show that all the prepared Ni-doped CdO films are degenerate semiconductors. However, the nickel doping influences all the optoelectrical properties of CdO. Their d.c. conductivity, carrier concentration and mobility increased compared to undoped CdO film. The largest mobility of 112.6 cm2/V.s was measured for 1-2% Ni-doped CdO film. From optoelectronics point of view, Ni-doped CdO can be used in infrared-transparent-conducting-oxide (NIR-TCO) applications.}

9 illus, 1 table, 39 ref

008528   Chopra K N (Applied Physics Dep, Maharaja Agrasen Institute of Technology, Rohini, Email: kchopra.2003@gmail.com) : Overview of optofluidics technology as novel approach for renewable energy. Invertis J renewable Energy 2014, 4(3), 140-8.

With, the increasing emphasis on the research efforts for exploring the possibility of novel approaches for the Renewable Sources of Energy, many interesting topics, including optofluidics have attracted the attention of various energy saving engineers. In addition to the well established renewable sources of energy - solar energy, wind energy, and geothermal energy, the energy technologists have explored the use of the new sources like - the humidity power. In addition, recently the use of optofluidics in making the renewable energy has been noticed. The present paper is a qualitative review of the efforts and results in this direction, besides describing briefly the computation of the energy produced by the devices based on this emerging technology, and is expected to be of great interest to the researchers engaged in finding the newer approaches for producing and saving energy.

7 illus, 26 ref

008527   Chaudhari K S;Toda Y R;Gujarathi D N (NO, S.V.S's Arts and Science College, Dondaicha, Email: vedsagar.ks@rediffmail.com) : Electrical properties of Pb_0.4In_0.6 se thin films deposited by physical evaporation technique. Invertis J renewable Energy 2014, 4(3), 127-31.

Thin films having different thickness of Pb_0.4 In_0.6 Se were deposited by thermal evaporation technique, onto precleaned amorphous glass substrate. The structural properties of films were evaluated by XRD, optical microscopy and Transmission Electron Microscopy (TEM). The electrical properties of annealed thin films have been evaluated. The resistivity of the films is determined over the thickness range of 1000 A, 1500 A, 2000 A, 2500 A and 3000 A. The temperature dependence of resistivity shows semiconducting behavior. The thickness dependence of resistivity is found to follow Fuch-Sondheimer size effect theory. Activation energy is found to be 0.067 to 0.083eV. Estimated values of Carrier concentration was 4.149 x10^{20 cm-3. Hall coefficients and Hall mobility were also determined. The estimated values of Hall mobility and Hall coefficients are 1.064 X 10-4 to 7.77 X 10-4 cm2/V-sec. and 6.202 X 10-8 to 1.7405 X 10-8 cm3/C respectively. Positive sign of the Hall coefficient shows P-type nature of films. The X-ray diffraction analysis confirms that films are polycrystalline having orthorhombic structure. The average grain size is found to be 6.342 nm.}

9 illus, 3 tables, 16 ref

008526   Bazhan Z;Ghodsi F E;Mazloom J (Physics Dep, Faculty of Science, Guilan Univ, Namjoo Avenue, P.O. Box 413351914, Rasht, Iran, Email: feghodsi@guilan.ac.ir) : Effect of stabilizer on optical and structural properties of MgO thin films prepared by sol-gel ethod. Bull Mater Sci 2013, 36(5), 899-905.

Effects of monoethanolamine (MEA) and acetylacetone (ACAC) addition as stabilizer on the crystallization behaviour, morphology and optical properties of magnesium oxide were investigated using thermogravi-metry (TG/DTG), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Visible, photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopy. Stabilizer addition reduces transparency of the films. MgO films prepared at 500 °C showed weak orientation of (200). However, the films prepared by addition of stabilizer are amorphous. MgO powders were prepared for exhibiting the structural properties. The patterns of MgO powders showed a preferred orientation of (200). The addition of stabilizer causes a reduction in grain size. SEM micrographs show that a homogenous and crack-free film can be prepared at 500 °C and addition of stabilizer causes an increase in packing density.

9 illus, 1 table, 26 ref

007409   Pachuau L;Sailo L;Pachuau Z;Lalngneia P C (Physics Dep, Mizoram Univ, Tanhril-796 004, Email: rinapachuau@yahoo.com ) : RF radiation from mobile phone towers and their effects on human body. Indian J Radio Space Phys 2014, 43(2), 186-9.

In the present paper, power density of RF radiation have been measured in close proximity (less than 50 m) to mobile base station Global System for Mobile Communications 900 (GSM 900) at the selected locality in Aizawl (23°44'53.5"N, 92°43'29.4"E), Mizoram, India. The mobile base station was erected in 2006. The study was carried out for the first time ever in the state in the year 2012 after six years of exposure to RF radiation with an aim to study different symptoms of health effects of RF radiation from mobile tower on nearby inhabitants. A survey was conducted on different health problems faced by the inhabitants living near the base station. Absolute power densities have been measured at some selected houses. Frequency spectrum was analysed at different sites. Different symptoms of RF exposure on human body are studied and the result is analysed. The measured power densities have been compared with standard limits given by various authorities, like International Commission on Non Ionizing Radiation Protection (ICNIRP), Bioinitiative 2012 and current National Standards. It has been observed that many inhabitants are having health complaints with different symptoms after the tower had been erected in 2006.

2 illus, 2 tables, 14 ref

007408   Neelakantaprasad B;Jegatheesan A;Murugan J; Aroulmoji V;Rajarajan G (Physics Dep, K.S.R. College of Engineering, Tiruchengode-637 215, Email: grajarajan@gmail.com) : Growth and characterization of new semi-organic L-asparagine potassium di-hydrogen phosphate crystals. Asian J Chem 2014, 26(1), 176-8.

The studies on the growth and characterization of a new semi-organic non-linear optical crystal, L-asparagine potassium dihydrogen phosphate have been successfully carried out by slow evaporation technique using deionized water as a solvent. The grown crystal is characterized by powder X-ray diffraction analysis and FT-IR analysis. The results of X-ray diffraction analysis showed that it possess orthogonal structure having lattice parameters a = 5.582 Å, b = 9.812 Å and c = 11.796 Å, α = β = γ = 90° and V = 514 Å^{3. The fourier transform infrared spectroscopy of L-asparagine potassium dihydrogen phosphate crystal were recorded between wave-number 4000 to 400 cm-1 showed very weak bands appearing around 1232 and 1147 cm-1 are due to P-O-H stretching and bending. The observed broad intense band in 3385-3119 cm-1 region is assigned to NH stretch of NH₂ vibration of L-asparagine potassium dihydrogen phosphate molecule. The CH2 vibration of the amino acid shows its peak at 2945 cm-1. The combination band observed at 2149 cm-1 is due to asymmetric NH₃+ vibration at 1643 cm-1 and NH₂+ tensional oscillation at 512 cm-1 and optical transmission spectral analysis. The lower cut off wavelength of L-asparagine potassium dihydrogen phosphate crystal occurs at 198 nm and it reveals that the material has good optical transparency in the entire visible region. The results of hardness test showed that the presence of dopant has enhanced the mechanical strength of the L-asparagine potassium dihydrogen phosphate crystals and the second harmonic generation of L-asparagine potassium dihydrogen phosphate crystals was tested using Kurtz and Perry method also showed good results.}

4 illus, 22 ref

007407   Kane R P (NO, Instituto Nacional de Pesquisas Espacias, INPE C P 515, 12201-970 Sao Jose dos Campos, SP, Brazil, Email: kane@dge.inpe.br) : Evolution of solar indices during the maximum of solar cycle 24. Indian J Radio Space Phys 2014, 43(2), 151-5.

Solar cycle 24 started in 2008-2009 and a first peak (<126>67) in sunspot number (12-month running means) occurred in February 2012. Recently, sunspot activity seems to have increased. The latest 12-month running mean attained a value 74.5 centered at September 2013 and is larger than the previous maximum 67. Thus, cycle 24 peak could be as high as <126>75 but further increase is not ruled out. Several other solar indices (2800 MHz solar radio flux, Lyman-α, Mg II 280 index, total solar irradiance, all of origin in chromosphere or lower corona) also showed peaks at February 2012. But coronal indices, X-rays and coronal mass ejection (CME) frequency showed broad plateaus around February 2012. In interplanetary parameters, solar wind speed (V) showed a broad peak earlier than February 2012 (during September 2010 - October 2011) and a decline thereafter. The number density (N) did not seem to have any relationship with solar indices, but magnetic field (B) peaked near February 2012. The geomagnetic index (Ap) showed the same pattern as B. The decrease in maximum (peak) cosmic ray intensity at middle and high latitudes showed a delay with respect to peak of solar indices by several (more than ten) months. The main conclusion of the present communication is that during the maximum of cycle 24, the finer dynamic characteristics of the solar surface (photosphere) phenomena extend faithfully to the chromosphere and lower corona, but local dynamical effects occur higher up in the corona diluting the effects of the photospheric phenomena.

1 illus, 1 table, 29 ref

007406   Calla O P N;Bohra D (NO, International Centre for Radio Science, Shastri Nagar, Jodhpur-342 003, Email: opnc06@gmail.com) : Measurement of forward scattering coefficient of different water bodies at different frequencies. Indian J Radio Space Phys 2014, 43(2), 178-85.

Thrust of this study is to analyse the effect of scattering of electromagnetic waves on microwave links and tracking of low flying objects in the presence of strong ground bounce return from water bound areas. For this purpose, a ground based bi-static forward scatterometer has been used to generate co-polarized specular data at CJ, X, and Ku bands. The measurements are carried out on three types of water surfaces, i.e. tap water, natural lake water and saline water. All the three water surfaces are assumed to be slightly rough surfaces at the frequency of interest. Therefore, small perturbation model of slightly rough surface for forward scattering is a good selection to analyse data. The scattered microwave power from the terrain measured for 25° - 70° scattering angle (θ_s) with an interval of 5° in specular direction with transmitting antenna placed at an incidence angle (θ_i) of 45° from nadir illuminates the terrain keeping φ_i = φ_s = 0° at 5.825, 9.472 and 13.4 GHz in CJ, X and KU bands, respectively for vv and hh polarization with different antenna heights. The forward scattering coefficient computed with the help of experimental geometry parameters, which then compared with estimated value of scattering coefficient obtained from small perturbation model of slightly rough surface. A good agreement between observed and estimated scattering coefficient for horizontal (hh) and vertical (vv) polarization has been found in X and KU bands with a polarization reversal in CJ band. It is also observed that dissolved salt or impurities increase the value of scattering coefficient. The basic purpose of this study is to map and monitor the natural resources and to provide timely inputs for the planners to develop appropriate strategies for optimum utilisation of the resources.

10 illus, 7 tables, 8 ref

007405   Amudha B;Raj Y E A;Thampi S B;Ramanathan R M A N (India Meteorological Dep, Regional Meteorological Centre, Chennai-600 006, Email: amudha2308@gmail.com) : Diagnostic and statistical approach to the validation of doppler radar rainfall around Chennai during 2006-2010. Indian J Radio Space Phys 2014, 43(2), 163-7.

Rainfall data obtained from the precipitation accumulation product of the Doppler Weather Radar at Chennai has been compared and validated with the rainfall recorded at 16 stations located within 100 km range of the radar. Statistical parameters, like correlation, mean error and mean absolute error have been calculated. When rainfall is indicated by both radar and observatory, a high degree of correlation, at 0.98, between the conditional means of radar and observatory rainfall in various ranges is observed along with consistency in underestimation of rain by radar. A regression equation has been constructed to correct the rainfall estimates from radar. Physics and radar engineering aspects, which contribute towards limitations in rainfall estimation, have been discussed.

9 illus, 2 tables, 43 ref

007404   Ahluwalia H S (Physics & Astronomy Dep, New Mexico Univ, Albuquerque, NM 87131, USA, Email: hsa@unm.edu) : Galactic cosmic rays, total solar irradiance, sunspots, earth surface air temperature: correlations. Indian J Radio Space Phys 2014, 43(2), 141-50.

Variation in the annual mean Earth surface air temperature is a key indicator of the climate change. An empirical search explores the connection among the long-term surface air temperature change (ΔT), the ionization caused by the galactic cosmic rays (GCRs) in the upper atmosphere, the interplanetary magnetic field (IMF) intensity (B) at the Earth orbit, the total solar irradiance (TSI) and the sunspot numbers (SSNs). Several scenarios are investigated with the world's longest and robust GCR data string for the instrumental era (1937-2013) covering eight SSN cycles (17-24). The data are further extended to 1900 to include three additional cycles (14-16). For ΔT comparisons, three datasets used are: the US surface air temperature (UST), the global surface air temperature (GST), and the land ocean temperature (LOT). For 1900-1955 and 1968-1987, an inverse correlation between GCR and GST is obtained. For 1956-1967, GCR intensity changes significantly (<126> 18%) with little change in GST. A positive correlation is obtained between GCR and GST for 1988-2008, implying that GCRs contribute to global warming. These results lead to infer that there is no sustained GCR - GST relationship, i.e. changes in GCR flux does not affect GST. Recent results from the CLOUD experiment are consistent with this inference. A comparison between the amplitude of the solar wind electric field and GST leads to an inconclusive result as well. It is also noted that TSI does not contribute to ΔT either. The historic evidence and the predicted trend for peak activity [Ahluwalia H S & Jackiewicz J, Sunspot cycle 23 descent to an unusual minimum and forecasts for cycle 24 activity, Adv Space Res (UK), 50 (2012) pp 662-668, doi:10.1016/j.asr.2011.04.023, 2012] for future cycles (25 and 26) suggests that Earth may cool in the next three decades, in contrast to IPCC [IPCC, Climate change 2007: The physical basis, Eds: S Solomon et al. (Cambridge Press, New York), 2007] consensus that GST will rise 4°C ± 2°C in the year 2100.

14 illus, 53 ref

006453   Yerpude A N;Dhoble S J (Physics Dep, RTM Nagpur University, Nagpur-440 033, Email: sjdhoble@rediffmail.com) : Photoluminescence properties of X5SiO4Cl6:Tb3+(X=Sr, Ba) Green phosphor prepared via modified solid state method.. Bull Mater Sci 2013, 36(4), 715-17.

Luminescence property of a new halo silicate phosphor, X₅SiO₄Cl₆:Tb^{3+ (X = Sr, Ba) prepared by modified solid state method is reported here. It is characterized by powder X-ray diffraction and studied by photoluminescence excitation and emission spectra. In the emission spectra of X₅SiO₄Cl_6:Tb3+ (X = Sr, Ba) phosphor, characteristic blue and green emission peaks are present corresponding to Tb3+ intra 4f transition. Emission spectrum shows a dominant peak at 544 nm due to the 5D_4→7F₅ transition of Tb3+.}

006452   Veliyev R G;Seyidov M H Y;Kero,pva E M; Sadykhov R Z;Asadov Y G;Seyidov F M;Gasanov N Z (NO, Institute of Physics, Azerbaijan National Academy of Sciences, Az 1143, Baku, Azerbijan, Email: ramizveliyev@gmail.com) : Phase transitions and their co-existence in TlGaSe₂-TlCrS₂(Se₂) systems. Bull Mater Sci 2013, 36(4), 693-8.

Investigation of dielectric properties of layered compound, TlGaSe2, showed that it is a ferroelectric (T_c = 105.5 K) with an intermediate incommensurate phase (T_i = 114.5 K). Our magnetic studies of layered compounds, TlCrS₂ and TlCrSe₂, for the first time revealed that the magnetic phase transition in these compounds are quasi two-dimensional ferromagnetic in nature and magnetic characteristics are T_C = 90 K, T^{p_C = 115 K, μ _eff = 3.26 μ and T_C = 105 K, Tp_C = 120 K, μ_eff = 3.05 μ B , respectively. Using the method of DTA, areas of homogeneous and heterogeneous coexistence of ferroelectric and ferromagnetic phase transitions in the systems, TlGaSe₂-TlCrS₂ and TlGaSe₂-TlCrSe₂, were identified. The low-dimensional solid solutions and eutectic alloys in these systems can be used as basic materials for plenty of functional recorders.}

6 illus, 2 tables, 18 ref

006451   Uniyal M;Bhatt S C (Physics Dep, H N B Garhwal Univ, Srinager Garhwal-246 174, Email: mani_uniyal@hotmail.com) : Polarizability investigation by first order phase transition in the self-consistent phonon approximation for PSN system. Indian J pure appl Phys 2014, 52(6), 391-4.

Considering a quadratic Anharmonic model Hamiltonian and using double time temperature dependent Green's function method and Dyson's equation treatment, expression for polarizablity in the frequency response for mixed perovskite type ferroelectrics has been obtained. Using the experimentally observed temperature dependent dielectric constant, loss tangent, soft mode frequency and width for Na_1-x K_xNbO₃ (where x = 0, 0.4 and 0.5), the polarizablity has been calculated for these samples at 10 and 100 kHz.

2 illus, 2 tables, 14 ref

006450   Tian Y;Yu Y;Jhu J;Zhang L;Bian L;Jin M;Zhang Q;Lu H;Senecha V (College of Science, Nanjing University of Posts and Telecommunications, , Nanjing 210003, People's Republic of China, Email: tianyw@njupt.edu.cn) : Spatial emission characteristics from electron oscillation driven by a circularly polarized few-cycle laser pulse. Indian J pure appl Phys 2014, 52(7), 450-6.

Full spatial emission characteristics of radiation generated from electron oscillations driven by a circularly polarized few-cycle laser pulse of different intensity have been investigated theoretically and numerically using a single electron model. The effect of laser pulse intensity and the initial phase on the process of full spatial characteristics of the radiation is apparent for few-cycle laser pulse. The characteristics can be used to measure the intensity and the initial phase of a circularly polarized few-cycle laser pulse in experiments.

11 illus, 18 ref

006449   Thangaraj N;Tamilarasan K;Sasikumar D (Physics Dep, Velalar College of Engineering and Technology, Erode-638 012, Email: dr.k.tamilarasan@gmail.com) : Effect of current density on electrodeposited ferrous tungsten thin films. Indian J pure appl Phys 2014, 52(6), 395-8.

Ferrous tungsten (Fe-W) electrodeposited thin film properties have been studied for different current densities and different deposition times. The magnetic saturation (M_s), retentivity (M_r) and coercivity (H_c) of the films have been studied using vibrating sample magnetometer. The retentivity (M_r) and the magnetic saturation (M_s) of the deposited films increased with the increase of current density. The crystallite size and stress of the deposited thin films were calculated using X-ray diffraction (XRD) studies. Percentage of elemental analysis of Fe-W films has been obtained using energy dispersive X-ray analysis (EDAX). Surface morphology analysis has been carried out using scanning electron microscope (SEM). The magnetic properties and structural characteristics of the thin films deposited under various experimental conditions are discussed. The hardness and adhesion of the deposited thin films were also studied.

3 illus, 2 tables, 15 ref

006448   Tangsrirat W;Unhavanich S (Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang (KMITL), Chalongkrung Road, Ladkrabang, Bangkok 10520, Thailand) : Voltage differencing transconductance amplifier-based floating simulators with a single grounded capacitor. Indian J pure appl Phys 2014, 52(6), 423-8.

Two simple configurations for simulating the resistorless floating inductor and capacitor using voltage differencing transconductance amplifier (VDTA) as a novel active element have been presented in this paper. The proposed floating simulated inductance circuit uses only one VDTA and one grounded capacitor, whereas the proposed floating simulated capacitance circuit uses two VDTAs and one grounded capacitor. The equivalent values of the realized simulators can be tuned electronically through the transconductance parameter of the VDTA. Both of the circuits also do not require any realization conditions. The proposed circuits together with their applications are demonstrated using PSPICE simulation with 0.35 μm TSMC CMOS technology.

12 illus, 1 table, 20 ref

006447   Siddiqui S A;Rasheed T;Bouarisa N (Advanced Materials and Nano-Research Centre, Najran University, Najran, KSA, Email: shamoonasiddiqui@gmail.com) : Investigation of superhalogen behaviour of RuF_n (n = 1-7) clusters: density functional theory (DFT) study. Bull Mater Sci 2013, 36(4), 743-9.

In the present investigation, interaction of ruthenium (Ru) atoms with fluorine (F) atoms was studied using the density functional theory utilizing B3LYP method. It was found that up to seven F atoms can bind to a single Ru atom which results in increase of electron affinities successively, reaching a peak value of 6.95 eV for RuF6. Its stability and reactivity were also examined by using HOMO-LUMO gap, molecular orbital analysis and binding energy of these clusters. It is found that energy required for dissociation of F₂ molecules are higher than energy required for dissociation of F atoms. The unusual properties are attributed to the involvement of inner shell 4d-electrons, which not only allow RuF n clusters to belong to the class of superhalogens but also show that its valence can exceed the nominal value of 1. The interaction of RuF₄ superhalogen with an alkali atom lithium (Li) were also studied which suggests that a new class of salt can be synthesized by reacting RuF₄ with Li.

10 illus, 1 table, 25 ref

006446   Shrivastava V;Patidar A K;Pensia R K (Physics Dep, Pacific University, Udaipur-313 024, Email: vijayendra.shrivastava@hotmail.com ) : Effect of quantum correction on thermal instability of self-gravitating two component plasma. Indian J pure appl Phys 2014, 52(7), 465-77.

The effect of quantum correction on thermal instability of magnetized, viscous self-gravitating two component plasma has been studied by means of linear perturbation analysis. The dispersion relation for longitudinal and transverse mode of propagation has been described and discussed it for some limiting cases. The condition of instability as well as stability of the system has been discussed by applying Routh-Hurwitz criterion. It is found that due to the self-gravitation of the medium, the condition of thermal instability changes into the condition of radiative instability. Quantum parameter affects the condition of radiative instability in both longitudinal and transverse direction of propagation, while the magnetic field affects only in transverse direction. It is concluded that the effect of viscosity, temperature dependent heat-loss function; quantum parameter and magnetic field have a stabilizing influence, while the thermal conductivity and density dependent heat-loss function have destabilizing influence on the Jeans instability.

6 illus, 32 ref

006445   Sastry S S;Venkateswara Rao B R (Physics Dep, Acharya Nagarjuna University, Nagarjunanagar-522 510, Email: sreeharisastry@yahoo.com) : Structural and optical properties of vanadium doped akaline earth lead zinc phosphate glasses. Indian J pure appl Phys 2014, 52(7), 491-8.

The structural properties of vanadium doped alkaline earth lead zinc phosphate glasses have been investigated by XRD, UV-Visible, EPR, FT-IR and Raman spectroscopy techniques. XRD analysis has confirmed that the samples are X-ray amorphous. The optical band gap energy (E_opt) is observed to decrease with the replacement of alkaline earth content, whereas reverse trend is observed in Urbach energy (ΔE) and optical basicity (Δth). The spin-Hamiltonian parameter, dipolar hyperfine coupling and covalency parameters have been obtained from EPR spectra. Depolymerization of the phosphate network by the replacement of alkaline earth content in glasses which are consisting of mainly PO₃^{2- and PO₄3-units, was detected by FT-IR spectra. The structural modification due to breakage of P=O bond and the formationof P-O-P bonds in the different compositions have been studied by Raman spectra. The physical properties have been measured and observed to increase with the replacement of alkaline earth content. The replacement of BaO has improved the strength of the cross-links between the phosphate chains of the glass.}

7 illus, 4 tables, 53 ref

006444   Sarkar A;Adhikari R;Das A K (Physics and Meteorology Dep, Indian Institute of Technology Kharagpur, Kharagpur-721 302, Email: amal@phy.iitkgp.ernet.in) : Development of a high vacuum cantilever beam magnetometer for measurement of mechanical and magnetic properties of thin films. Curr Sci 2013, 104(7), 826-34.

Cantilever beam magnetometer (CBM) is an apparatus by means of which in situ measurement of the mechanical and magnetic properties of thin films can be made. We report here on the development of a cost-effective home-built CBM set-up under the high vacuum conditions and demonstrate its ability to measure intrinsic stress during the growth of magnetic/non-magnetic thin films and thereafter the magnetization of the magnetic films as a function of the magnetic field. The reproducible performance of the set-up has been demonstrated with various magnetic and non-magnetic films deposited on the p-Si(100) substrates.

^ssc10 illus, 31 ref