017110   Subramanyam Naidu P;Ravindra Prasad K (Dep of Physics, SVUPG Centre, Kavali-524201) : Ultrasonic velocity and allied parameters in solutions of cypermethrin with xylene and ethanol. Indian J pure appl Phys 2004, 42(7), 512-17.

Ultrasonic velocity, density and visocosity have been measured at different temperatures in the binary mixtures-(1)cypermethrin + xylene and (2) cypermethrin + ethanol. Various acoustical and allied parameters have been computed and the results have been presented in the light of the molecular interactions between the like and unlike molecules. Solvation numbers, apparent molar compressibility etc., have also been evaluated which in turn are employed in the study and confirmation of molecular interactions (solute-solute and solute-solvent). Solute-solvent interactions have been suggested to be dominant in both the mixtures.

4 illus, 6 tables, 16 ref

017109   Singh C;Sidhu G S;Ashok Kumar;Singh P S; Mundahar G S (Physics Dep, Punjabi Univ, Patiala-147002) : Simultaneous effect of collimator size and absorver thickness on the gamma ray build up factor. Indian J pure appl Phys 2004, 42(7), 475-8.

The build-up factor values have been measured for 662 ke V gamma rays in the extended media of bakelite and perspex under different colimation conditions. A correlation effect has been obtained in the measurement due to collimator size and absorber thickness to prevent the multiple scatter photons reaching the detector.

3 illus, 8 ref

017108   Sharma S B;Singh T B;Gartia R K (Luminescence Dating Laboratory, Manipur Univ, Imphal 795003) : Critical evaluation of goodness of fit of computerised glow curve deconvolution. Indian J pure appl Phys 2004, 42(7), 492-7.

Computerised glow curve deconvolution (CGCD) technique is a powerful tool for evalution of trapping parameters of the thermoluminescence glow curve. A difficulty in the outcome is the level of confidence is accepting the values of the parameters that the technique yields. At this juncture the importance of goodness of fit test arises to compare the deviations of experimental from the expected values obtained from the model. A far as dosimetric application is concerned the leaders of the filed have propagated the Figure of Merit (FOM) as criteria to test the goodness of fit. Three well accepted conventional methods of goodness of fit statistics namely Discrepancies (DIS), Reduced, Chi-squre and Chi-square (χ² test are used with FOM to critically evaluate the potentialities of the statistical tests. Glow curves of iodised salt are taken as reference glow curves.

4 illus, 1 table, 4 ref

017107   Rajnikant;Dinesh Kumar;Sharma B (Condencsed Matter Physics Group, Univ of Jammu, Jammu Tavi 180006) : Crystallographic analysis of 1H, 4H-tetrahydro-8-methlyl-quinolizino-(9,9a,1gh) coumarin. Indian J pure appl Phys 2004, 42(7), 524-7.

The crystal structure of 1H,4H-tetrahydro-8-methyl-quinolizino-(9,9a,1gh) coumarin (C₁₆H₁₇NO₂) has been determined by X-ray crystallographic techniques. The compound crystalizes in monclinic space grou P2₁/n with unit cell parameters: 1=8.6659(5) Armstrong, b=10.251(5) Armstrong, c=14.508(5) Armstrong β=96.61(1)°, Z=4, V=1278.91(11) Armstrong₃. The sturcture has been solved by direct methods and refined upto reliability index of 4.8%. The fused benzene and pyrone rings are planer. Both the piperidine rings exist in distorted sofa conformation. The crystal structure is stablized by C-H...O hydrogen bonds.

3 illus, 4 tables, 21 ref

017106   Menon V J;Patra B K;Dubey R K (Dep of Physics, Banaras Hindu Univ, Varanasi 221005) : Non-orthogonality of lippmann-schwinger-low states. Indian J pure appl Phys 2004, 42(7), 485-91.

For the general short-ranged potential the Lippmann-Schwinger-Low (LSL) scattering formalism by taking the limit ∈→+O at the end of the analysis, with ∈ being an infintestimal adiabatic parameter has been re-examined. It is found that the LSL state <202>Ψ^L_m<209> dose not strictly satisfy the Schrodinger eigen equation, and the pair <202>Ψ^L_m<209>,<202>Ψ^L_k<209> is mutually non-orthongonal if E_n=E_k, n≠ k. For this purpose a new type of projection operatorη_Ok, a non-linear relation among transition amplitudes, and a separable interaction as illustration have been used.

illus, tables, ref

017105   Majumdar K (Electronics and Communication Sci Unit, Indian Statistical Inst, 203, B T Road, Kolkata-700 108) : A study of fluctuation in radon concentration behaviour as an earthquake precursor. Curr Sci 2004, 86(9, 10), 1288-92.

Before, during and after many large earthquakes significant change in concentration of radon has been observed in China, Japan and India. To establish this behaviour as a potential earthquake precursor, it is important to understand the phenomenon in terms of geodynamics. Here I propose a geodynamic model to establish a correlation between precursory radon concentration fluctuations and an impending earthquake. The model has been validated by field data collected from Japan and China. Further investigation with this model also helps to find a possible explanation for abnormal variation in the geomagnetic field intensity observed before, during and after some earthquakes.

5 illus, 19 ref

017104   Mackay T G;Lakhtakia A (School of Mathematics, Univ of Edinburg, Edinburgh EH9 3JZ, UK) : Negative refraction in outer space. Curr Sci 2004, 86(12), 1593.

8 ref

017103   Lal R;Sharma N D (Dep of Physics, Kurukshetra Univ, Kurukshetra 136119) : Mossbauer and infrared studies of some glasses and glass-ceramics from the XMn(40-X)YFe₂O₂. 50B₂O₃ system. Indian J pure appl Phys 2004, 42(7), 498-505.

The ⁵⁷Fe Mossbauer technique has been used to investigate the behaviour of glasses and their corresponding glass ceramic derivatives obtained from the system XMn(40-X)YFe₂O₃.10Al₂O₃.50B₃, along with the effect of Al and Mn doping at the Fe-site for all the samples. MnO was introduced gradually to replace Fe₂O₃ in the series such that X=0.5,10,15,20 and 25 mol% of MnO containing 50% F₂O₃. The structural changes observed are consistent with Mn₂O₃ formulation and inferred by monitoring the infrared absorpition spectra in the range 500-400cm^-1 by KBr technique. The Mossbauer technique is used for indentification of crystalline material and the results are compared with that obtained from X-ray diffraction.

3 illus, 2 tables, 34 ref

017102   Kher S;Shrikant G;Saxena M K;Nathan T P S (Fibre Optics Laboratory, Solid State Laser Div, Centre for Advanced Technol, Indore-452 013) : Development of distributed fibre optic temperature sensor with sub-metre resolution. Curr Sci 2004, 86(9, 10), 1202-04.

3 illus, 3 ref

017101   Jain A P;Parashar J (Dep of Applied Physics, Samrat Ashok Technological Institute, Vidisha-464 001) : Space perodic thermionic emission and ablation of metallic targets by crossed surface plasma waves. Curr Sci 2004, 86(12), 1608-10.

Two surface plasma waves (SPWs) propagating at an angle to each other over a metal-free space interface, cause space periodic heating of electrons. As the electron temerpature T_e rises, thermal conduction transverse to the interface and collisional heat transfer to the lattice become dominant heat-loss mechanisms. On the time scale of a few collision time, the lattice gets heated, giving rise to space periodic ablation that leads to the formation of grating structures. In case the SPW power is below the threshold for ablation, space periodic electron temperature results in space periodic thermionic emission.

2 illus, tables, 17 ref

017100   Jagjiwanram;Singh R (Thermal Physics Lab, Phys Dep, Univ of Rajasthan, Jaipur-302 004) : Determination of thermal conductivity of high porosity organic foams at varying temperatures and pressures using thermal probe method. Indian J Engng Mater Sci 2004, 11(2), 125-9.

The thermal conductivity of organic foams at varying temperatures (-20 to 30°C) and interstitial air pressures has been measured using thermal probe method. Experiment has been conducted on different cell sizes of organic foam samples covering a vide range of porosities. Results show that the effective thermal conductivity decreases with increasing porosity and increases by increasing temperature and interstitial air pressure values. Data obtained from the experiment has been compared with the reported model and found good agreement between experimental and theoretical results at room temperature and normal pressure.

8 illus, 2 tables, 10 ref

017099   Gupta N;Tyagi B P (Dep of Physics, Graphic Era Institute of Technology, Dehradun, Uttranchal) : Efffect of grain size on the mobility and transfer characterstics of kpolysilicon thin-film transistors. Indian J pure appl Phys 2004, 42(7), 528-32.

The effect of the grain size on the effective carrier mobility (μ_eff) and tranfer characterstics of a polycrystalline silicon thin film transistor (poly-Si TFT) have been theoretically investigated by developing an analytical model. The dependence of μ_eff is studied as a function of doping concentrations and gate voltage for different vlaues of grain size. It is observed that at low as well as at high dping concentrations, the effective carrier mobility (μ_eff) increases with increase in grain size, whereas the observed dip at the intermediate doping concentration is getting confirmed. The effect of the grain size on transfer characteristics of poly-Si TFT in its linear region is also presented. It is found that at low gate viltages, (μ_eff) and I_D increase rapidly with the increase in V_G for all values of grain sizes due to the grain boundary barrier lowering effect. At high gate voltage the grain boundary barrier lowering effect becomes insignificant and causes the saturation of (μ_eff) and I_D. The model was found to account correctly for the epxerimentally observed mobility variation and yield a reasonably good agreement.

6 illus, tables, 13 ref

017098   Gartia R K;Sharma B A;Ranita U (Luminescence Dating Laboratory, Manipur Univ, Imphal-795 003) : Thermoluminescence response of some common brands of iodised salt. Indian J Engng Mater Sci 2004, 11(2), 137-42.

Thermoluminescence (TL) response of ten Indian brands of iodized salt has been recorded for possible use in TL dosimetry. It has been observed that a heat treatment of one minute at 500°C reduces the complexity of the glow curve pattern. Further, in many cases heat treated samples exhibit intense peaks at higher temperature which are stable at room temperature (25°C) wherease some brands like Sungold, Tata, Ankur and Dandi inhibit such peaks. TL response of two such cases namely the integration the integration zone 200-400°C of the glow curve of Taja and Shudh brands of iodized salt follow polynominal of degree three to beta exposure in the dose range 1 to ~- 25 Gy; indicating its potentiality the TL dosimetry.

6 illus, 2 tables, 11 ref

017097   Chavhan S D;Patil A R;Sharma R P (Thin Film and Semiconductor Lab, Res Centre, Phys Dep, G T Patil Coll, Nandurbar-425 412) : Studies on structural, optical and photoelectron transportation in solution grown nanosize CdS thin films for photosensor application. Indian J Engng Mater Sci 2004, 11(2), 130-6.

9 ills, 2 tables, 39 ref

017096   Chandel P S;Thakur A;Goyal N;Tripathi S K (Centre of Advanced Study in Physics, Punjab Univ, Chandigarh) : Dielectric relaxation studies of (Ge₂₀Se₈₀)0.90 Sn_0.10 glassy alloy. Indian J pure appl Phys 2004, 42(7), 539-43.

The frequency and temperature dependece of ac conductivity measurements have been made on (Ge₂₀Se₈₀)_0.90Sn_0.10 glassy alloy in the frequency range 2-50 kHz and in the temperature range 273-373K. Dielectric constant (ε') has been calculated using this data. The results indicate that dielectric dispersion occurs in this temperature and frequency range. The dielectric loss (ε") and loss angle (tanδ) have been calculated using Gever's relation. The temperature dependence of dielectric loss (ε") shows relaxation peaks as a function of temperature. These relaxation peaks shift towards the higher temperature as the frequency is increased. A detailed analysis of the data shows that the results can be explained in terms of dipolar relaxation with a distribution of relaxation times, which is quite expcected in case of chalcogenide glasses.

4 illus, 2 tables, 16 ref

017095   Burghate D K;Deshmukh S H;Joshi L;Deogaonkar V S;Deshmukh P T (Postgraduate Dep of Physics, Shri Shivalji Science College, Amravatti444603) : Electrical conduction of succinic acid doped glycine pellet. Indian J pure appl Phys 2004, 42(7), 533-8.

The electrical conduction of succinic acid doped glycine pellet has been measureed by studying the I-V characteristics at various temperatures in the range 313-353 K. The results are presented in the form of I-V characteristics, and analysis has been made in the light of Pool-Frenke, Fowler-Nordheim, Schottky, log(J) versus T plots, Richardson and Arrehenius plots. Results analysed suggest that, Schottky-Richardson mechanism is primarily responsible for observed conduction.

8 illus, 1 table, 24 ref

017094   Benerji N S;Varshnay N;Lala Abhinandan;Nundy U (Chemical and Excimer Laser SEct, Cen for Adv Technol, Indore-452 013) : A compact spark pri-ionized pulser sustainer TE-Co₂ laser. Sadhana 2004, 29(3), 297-303.

A compact spark pre-ionized pulser sustainer TE-CO₂ laser that can produce an output energy of one joule with an overall efficiency of 12.4% is presented. Optical pulses have durations of 7.15μs FWHM. Here, the laser uses all solid-state excitation (ASSE) circuit and the discharge formed between two uniform field electrodes placed 1.5 cm apart ultimately leads to a discharge colume of 50 cm x 1.5 cm z 1.5 cm.

6 illus, 14 ref

017093   Batra V;Dutta A;Biswas S (Dep of Physics & Astrophysics, Univ of Delhi, Delhi-110 007) : Charge spectrum of ultra heavy ray ions (Z=68-96) measured onboard long duration exposure facility. Indian J pure appl Phys 2004, 42(7), 479-84.

The results of the abundance of relativistic ultra heavy (UH) nuclei with charge Z<62> 65 from an analysis of detectors exposed in space by Ultra Heavy Cosmic Ray Experiment (UHCRE) conducted onboard NASA's Long Duration Exposure Facility (LDEF) are presented. A total of 72 events including two antinides (88≤ Z ≤ 100) have been indentified from the scanning of <126>0.21m² deteror area. A peak at Z=78 and a smaller peak around Z=85 could be seen. The charge fragmentation of the cosmic ray ions had also been within the detector stak. The detailed analysis of charge spectrum for the elements in the charge region, Z=65-96, is presented. An enhancement of r-process elements relative to solar system is observed. The results suggest a mixed source of rapid (r) and slow (s) process nuclei with Z<62> for cosmic rays in space.

3 illus, 3 tables, 17 ref

017092   Athiannan K;Palaninathan R (Structural Mechanics Section, Reactor Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102) : Experimental investigations on buckling of cylindrical shells under axial compression and transverse shear. Sadhana 2004, 29(1), 93-115.

Presents experimental studies on buckling of cylindrical sheel models under axial and transverse shear loads. Tests are carried out using an experimental facility specially designed, fabricated and installed, with provision for in-situ measurement of the initial geometric imperfections. The shell models are made by rolling and seam welding process and hence are expected to have imperfections more or less of a kind similar to that of real shell structures. The present work thus differ from most of the earlier investigations. The measured maximum imperfections δ_max are of the order of ±3t (t = thickness). The buckling loads obtained experimentally are compared with the numerical buckling values obtained through finit element method (FEM). IN the case of axial buckling, the imperfect geometry is obtained in four ways and in the case the transverse shear buckling, the FE modelling of imperfect geometry is done in two ways. The initial geometric imperfections affect the load carrying capacity. The load reduction is considerable in the case of axial compression and is marginal in the case of transverse shear buckling. Comparisons between experimental buckling loads under axial compression, reveal that the extent of imperfection, rather than its maximum value, in a specimen influences the failure load. Buckling tests under transverse shear are conducted with the without axial constrains. While differences in experimental loads are seen to exist between the two conditions, the numberical values are almost equal. The buckling modes are different, and the experimentally observed and numerically values are in complete disagreement.

12 illus, 5 tables, 25 ref

016086   Ravat K B;Mahajan S K (NO, National Phys Lab, New Delhi-110 012) : Establishment of DC high voltage standard at National Physical Laboratory. Bhartiya Vaigyanik Evam Audyogik Anusandhan Patrika 2004, 12(1), 139-42.

In the beginning of this millennium National Physical Laboratory, New Delhi has established DC high voltage measurement facility up to 100 kV. It is a unique calibration facility in India. The main theme of this laboratory is to maintain and upgrade DC high voltage standards through continuous research development. The principle of calibration is based on the comparison method. The ratio of standard divider is 100000/10 and uncertainly is 0.01%. The DC High Voltage standard is traceable to primary standard of voltage i.e., Josephson voltage standard with the expanded uncertainty of measurement at k=2. The standard divider and the UUC divider are put in parallel and supplied with a HV source up to 100 kV. The output voltage at the lower end of the standard divider as well as UUC divider are measured with the help of two separate calibrated multimeters. Standard divider ratio is used to define the HV source voltage. In to days' world transmission by means DC high voltage is considered to be the most appropriate.(Hindi)

016085   Gupta S K;Pant R P;Arora M (Materials Characterization Div, Nation Phys Lab, Dr K S Krishnan Road, New Delhi-110 012) : Different ferrofluid systems by electron paramagnetic resonance technique : a review. Bhartiya Vaigyanik Evam Audyogik Anusandhan Patrika 2004, 12(1), 143-5.

Magnetic fluids have been receiving considerable importance due to their wide range of technological applications in the domain of nano-structured material. In such fluids magnetic particles are randomly dispersed in carrier fluid and resembles like a paramagnetic gas. In this paper we reviewed our earlier EPR work on different ferrofluid systems viz. ionic ferrofluid, ferrofluid - conducting polymer composite, magnetite particles dispersed in PVA polymer matrix composite films. Single domain Fe₃O₄ magnetic particles of size 10 to 100 AÅ are dispersed in carrier fluid like water, diester, paraffin and other liquid hydrocarbons and are similar to colloidal state. In these ferrofluids, EPR spectra showed a single, isotropic broad line spectra at all temperature.(Hindi)

015213   Yadava S S;Yadav A (Chem Dep, DDU Gorakhpur Univ, Gorakhpur-273 009) : Ultrasonic behaviour of binary liquid mixtures of 1-bromopropane with cyclohexane and benzene. Indian J pure appl Phys 2004, 42(5), 338-40.

Ultrasound velocity and densities of the binary mixture of 1-bromo-propane with cyclohexane and benzene over the whole composition range at 308.15 K have been measured. The adiabatic compressibilities and deviation from ideal adiabatic compressibilities have been evaluated. The value of ultrasound velocity decreases and comes to a minimum and then increases as the mole franction of 1-bromopropane increases in the binry mixture with cyclohexane and benzene. The variation of adibatic compressibilities with mole fraction is sigmoid for both the mixture. The excess adiabatic compressibility of binary mixture with cyclohexane is positive at all concentrations, while it is negative at lower mole fractions of 1-bromopropane of the binary mixture with benzene and positive at higher mole fractions. The results are discussed in terms of molecular interactions.

3 illus, 17 ref

015212   Yadav S L;Yadav A K (Univ of Phys Dep, L.N. Mithila Univ, Darbhanga-846 004) : The concepts of space and time in the context of the special theory of relativity. Appl Sci Period 2004, 6(1), 15-25.

In spite of its spectacular success in all other respects, many scientists and philosophers have challenged the assumptions of relativity and proposed alternative theories. Yet special theory of relativity is often held up as a pinnacle of men's mental achievement a monuments to physical insight and mathematical logical. A new scale factor has been introduced between two inertial frames and Lorentz transformations has been derived in two different ways.

7 ref

015211   War T A;Chandan A;Devi R;Khosa S K;Bharti A (Phys and Electronics Dep, Jammu Univ, Jammu-180 006) : Importance of hexadecapole interactions in even-even germanium and selenium isotopes. Indian J pure appl Phys 2003, 41(12), 914-21.

Variation after projection (VAP) calculations in conjunction with Hartree-Bogoliubov (HB) ansatz have been carried out for germanium and selenium isotopes. In this framework, the yrast spectra with J^II≤10⁺, B(E2) transition probabilities, quadrupole deformation parameter (β₂) have been obtained. The results of the calculation give an indication that, it is important to include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities in Ge and Se isotopes. Besides this, it is important to include 2d_5/2 orbit in valence space for making nuclear structure calculations in Ge-Se mass region.

4 illus, 4 tables, 32 ref

015210   Verma N K;Kumar S;Bhatti H S;Singh S (School of Physics and Material Science, Thapar Institute of Engineering & Technology, Patiala - 147 004) : Effect of killer impurities on laser excited doped Zns phosphors. J Optics 2003, 32(2), 69-73.

Zinc sulphide phosphors, doped with Ba and Mg as well as killer impurities of Fe, co and Ni having variabl concentrations have been synthesized and then using ultraviolet laser (Nitrogen Laser) as the exciation source, their decay-curve analysis has been done. Various strong emissions have been detected and the corresponding excited state lifetimes are measured at room temperature. Studies have also been carried out to see the effect of different dopant concentrations on the phosphorescence excited-state life times.

2 illus, 1 table, 12 ref

015209   Verma D;Verma M L;Verma A;Rathore R P S (A F Sch of Engng and Technol, , Dhauj-121 004, Haryana) : Cohesion, elastic constants and vibrational mechanics of fcc platinum. Indian J Phys-Pt A 2004, 78(3), 337-41.

A model in real space has been developed by extending the generalized form of the exponential potential known as extended generalized exponential potential (EGEP) to account for (a) the correct nature of repulsive and attractive components of forces for all the separations in general and that of small separations in particular, (b) the three-body forces such as volume forces in an indirect way in the framework of EGEP through the parameter n, (c) the dielectric screening functions in an alternative and simpler form through the parameter m. The model is employed to compute the cohesive energy, second-order elastic constants and phenon spectra for fcc platinum. The predictions show promising agreement with experimental findings.

1 illus, 5 tables, 35 ref

015208   Uniyal M;Bhatt S C;Bhandari R;Ramchandra Rao M S;Pant R P;Semwal B S (Dielectric & Ultrasonic Lab, Phys Dep, H N B Garhwal Univ, Srinagar Garhwal (Uttaranchal)-246 174) : Temperature and frequency dependence of width in sodium potassium niobate mixed system. Indian J pure appl Phys 2004, 42(5), 341-6.

Considering a quadratic anharmonic model Hamiltonian and using double time temperature dependent Green's function method and Dyson's equation treatment, expression for the width in the frequency response for mixed perovskite type ferroelectrics have been obtained. Using the experimentally observed dielectric constant and loss tangent for Na_1-xK,v>xNbO₃ [where x = 0, 0.4, 0.5], the temperature dependence of soft mode width in these samples at 10 and 100 kHz has been calculated. Anomaly has been observed in the behaviour of soft mode width, near the transition temperatures in these compounds.

3 illus, 3 tables, 11 ref

015207   Tripathy S;Ananda Rao S (Department of Physics, Jaganath Institute for Technology and Management, Paralakhemundi, Orissa - 761 200) : Optical bistability in a magnetic semiconductor. J Optics 2003, 32(2), 59-67.

Recently magnetic semiconductors are found to exhibit optical bistability. Tries and succeds in giving a theoritical model for optical bisability in a magnetic semiconductor. Using this model it is found that the decrease of magnetic impurity concentration or interaction potential favours this bisability phenomenon. Finally this model is tested fo diluted magnetic semiconductors.

4 illus, 14 ref

015206   Tiwari M;Vijay Singh;Gundu Rao T K;Dhoble S J (Phys Dep, Reg Inst of Edu, Bhopal-462 013) : ESR and thermoluminescence studies of bismuth doped calcium sulphide phosphors. Indian J pure appl Phys 2004, 42(5), 323-5.

Thermally stimulated luminescence (TSL) and electron spin resonance (ESR) studies were carried out on bismuth doped CaS phosphor synthesized by using solid-state reaction technique. The defect centers formed in CaS:Bi were studied using the technique of electron spin resonance. The thermoluminescence glow curve shows two peaks at about 400 and 505K. Irradiated CaS:Bi exhibits ESR lines due to defect centers. Thermal annealing behaviour of the phosphor indicates that one of the defect centres correlated with the TSL peaks at 400 and 505K. The center is characterized by an isotropic g-value of 2.0034 and is assigned to a F⁺ center.

3 illus, 13 ref

015205   Tewari S P;Silotia P;Saxena A (Phys and Astrophys Dep, Univ of Delhi, Delhi-110 007) : Ground state properties of BECs of <. Indian J pure appl Phys 2003, 41(12), 905-13.

Ginzburg-Pitaevskii Gross (GPG) non-linear equation for the Bose Einstein Condensate (BEC) having different number of ⁸⁷Rb atoms (in the range 10² to 5x10⁶) in an isotropic magnetic trap, has been numerically solved to obtain its eigenvalue, the chemical potential, and the corresponding wave function, to study its various observable physical properties, such as, the correlation length, healing length, inter-particle separation in the core and the speed of sound in the condensate. These have been compared with the corresponding results computed by using the approximate expression obtained in the limiting case when the number of atoms in the condensate tends to a large value, that is, is in the Thomas-Fermi approximation. Significance and inter-relationships of various physical quantities have also been discussed in the light of recent experimental results.

9 illus, 15 ref

015204   Suresh Swapna S;Chandramouli V (Phys Dep, Osmania Univ, Hyderabad-500 007) : ESR, optical absorption and transport studies of Cu<. Indian J pure appl Phys 2003, 41(12), 954-60.

5 illus, 4 tables, 21 ref

015203   Srikanth G;Nathan T P S (Solid State Laser Divsion, Centre for Advanced Technology, Indore-452 013) : Ceramic reflectors for solid state lasers. J Optics 2003, 32(2), 75-7.

The work carried out to identify a suitable ceramic diffuse reflector, for optical pumping in visible-near IR region of solid-state laser medium using arc lamps, flash lamps or laser diodes is reported. Reflecting properties and effects of UV exposure on reflectivity of alumina discs prepared with different purity (percentage of alumina) and with different fabrication processes have been experimentally studied.

1 illus, 2 ref

015202   Soni P H;Desai C F;Bhavsar S R (Phys Dep, Faculty of Sci, Vadodara-390 002) : Creep activation energy of flow process of Sb_0.2Bi_1.8Te₃ single crystals. Indian J pure appl Phys 2004, 42(5), 371-4.

Temperature dependence of the Vickers microhardness of Sb_0.2Bi_1.8Te₃ single crystals has been studied. Loading time dependence of microhardness at different temperatures has been used for creep study in the temperature range 303-373 K. The activation energy for indentation creep of the crystals has been evaluated.

4 illus, 22 ref

015201   Singh M P;Bhandari C M (Phys Dep, , ) : Electronic transport in one-dimensional systems. Indian J pure appl Phys 2003, 41(12), 950-3.

Electronic thermal transport and electrical transport in quasi one-dimensional structures is the subject matter of the communication. Expressions have been obtained for electronic thermal conductivity, electrical conductivity and Lorenz factor. Results of calculation of polycrystalline bismuth telluride have been presented at 300 K for different carrier densitives and wire diameters. It is concluded that, cross-sectional size of the wire influences the Lorenz factor in carrier density range 10²³-10²⁶m^-3. Effect of cross-sectional size on electrical conductivity and electronic thermal conductivity is appreciable at carrier densities above 10²³ m^-3.

3illus, 1 tables, 18 ref

015200   Singh G S;Jain P K;Narasimham M L;Bajpai R P (Advanced Optical Processing Division, Central Scientific Instruments Organization, Sector-30, Chandigarh - 160 030) : Determination of kinematics of four component mechanically compensated zoom lenses. J Optics 2003, 32(2), 87-106.

Describes a simple method developed to solve the most complex problem of kinematics determination of various types of four-component mechanically compensated zoom lenses. It has been shown that how a sinple paraxial conjugate equation, along with magnification equation can be used successfully to solve the Hercules problem of component displacement in a four componnt mechanically compensated zoom lens. This method provides a deep in sight into the image formation process by a zoom lens. The method developed is applicable for all types of four-component mechanically compensated zoom lenses.

6 illus, 7 table, 9 ref

015199   Singh A K (Mathematics Dep, VSSD College, Kanpur-208 002) : Numerical solution of free convection flow of a micro-polar fluid past a porous vertical plate. Indian J pure appl Phys 2003, 41(12), 936-40.

An implicit finite difference method is applied to obtain the numerical solution of free convention flow of an incompressible micro-polar fluid past an infinite vertical porous plate taking into account transpiration effect. The effects of material constants, transpiration parameter and Prandtl number are observed on velocity field and skin-friction. In addition, the effects of material constant and Prandtl number are also obwerved on micro-rotation of the micro-polar fluid.

3 illus, 19 ref

015198   Shukla R P;Udupa D V;Das N C (Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai - 400 085) : A note on a set of wedge plates for laser beam collimation testing. J Optics 2003, 32(2), 79-85.

A set of wedge plates required for setting up lateral shearing interferometer for laser laser beam collination testing of various apertures has been suggested in order to obtain maximum sensitivity in the detection of laser beam decollimation. The wedge angle of the plate may vary fom an angle of 2.5 arc-sec to 60 are-sec whereas the suitable thickness of the wedge plate may vary from 3 mm to 66 mm depending on the size of the laser beam under test. As set of ten wedge plates is suggested fo checking the laser beam decollimation of apertues varying from 3 mm to 100 mm.

5 illus, 1 table, 7 ref

015197   Shah N A;Malik M A (Postgraduate Dep of Electronic & Instrumentation Technol, Univ of Kashmir, Srinagar-190 006) : High input impedance HP, BP and LP filters using FTFNs. Indian J pure appl Phys 2003, 41(12), 967-9.

Presents a new multifunction filter based on and employing four terminal floating nullors (FTFNs) which simultaneously realizes bandpass (BP) and lowpass (LP) filtering functions. The circuit can be made to realize highpass (HP) and bandpass (BP) filtering signals as well by changing one admittance and exhibits high input impedance thus, facilitating cascading of such circuits to realize higher order filters. The circuit employs grounded capacitors which suits contemporary IC design techniques and has the distinct feature of providing controllable gain of all the filtering functions through grounded passive components. Besides enjoying low passive sensitivity figures, the resonance frequency ω_o and bandwidth ω_o/Q are independently tunable in a sequential manner. PSPICE simulation results are also included.

3 illus, 12 ref

015196   Saxena M;Agarwal A;Bhatnagar P K (Applied Sci & Humamties Dep, Moradabad Inst of Technol, Ramganga Vihar Phase II, Moradabad-244 001) : Calorimetric measurements on Te-Bi-Se glasses with variation in Se content. Indian J Phys-Pt A 2004, 78(3), 343-6.

The alloys of Te-Bi-Se glass system, obtained by rapid quenching technique, have been characterized by calorimetric measurements and differential thermal analysis for different heating rates. A systematic investigation of crystallization kinetics of Te-Bi-Se glass system is carried out for the composition range in which amorphous alloys with a large glass forming ability in Se-based systems, the glass transition temperature T_g and the peak temperature T_p at different heating rates have been studied with the increase in Se content. With the increase in heating rates, T_g and T_p are found to increase. This analysis helps in finding the suitability of an alloy to be used in phase transition optical memories/switches. Thermal stability of these glasses is found in good command to form the glasses with ease.

5 illus, 18 ref

015195   Sarma R;Mazumdar N;Das H L (Phys Dep, Gauhati Univ, Guwahati-781 014) : Study of trap depth characteristics in ZnTe thin films based on photocurrent decay. Indian J Phys-Pt A 2004, 78(3), 389-91.

Photocurrent decay characteristics were studied in zinc telluride thin films deposited by thermal evaporation on glass substrates held at room temperature (290K). Two different decay times of photocurrent were found which correspond to two distinct trap depths. The trap depths were found to increase with ambient temperature and intensity of white light illumination. The estimated trap depths range from 0.26 eV to 0.61 eV.

1 illus, 1 tables, 15 ref

015194   Sakwar W T;Khanna K M;Mueni M;Rotich S; Torongey P K (Phys Dep, Moi Univ, PO Box 1125, Eldoret, Kenya) : Transition temperature for <. Indian J pure appl Phys 2004, 42(5), 351-4.

For pure ⁴He liquid the superfluid fraction starts having a finite value at and below the λ-transition temperature 2.176K, whereas for ⁴He in a disordered media the superfluid fraction starts having a finite value at 2.168K, a temperature that is lower compared to the temperature at which superfluidity appears in pure ⁴He. Relations for transition temperatures for both cases that are in agreement with experimental values have been obtained. Adsorption, which normally leads to a decrease in the degrees of freedom, consequently results in a released of heat, which destroys superfluidity. Hence for the liquid ⁴He following into a disordered medium, the transition temperature is expected to be lower.

2 illus, 2 tables, 7 ref

015193   Sakwar W T;Khanna K M;Mueni M;Rotich S; Torongey P K (Phys Dep, Moi Univ, PO Box 1125, Eldoret, Kenya) : Four-level approximation in disordered medium. Indian J pure appl Phys 2004, 42(5), 355-60.

The adsorption of superfluid ⁴He into a disordered medium, the disappearance of superfluidity due to adsorption, and the subsequent appearance of superfluidity when more ⁴He flows into the disordered medium have been described by the four level approxiamation. The adsorption of superfluid ⁴He into a disordered medium depletes the ZMS as the particles shift to higher excited levels resulting in `four-level approximatiation'. Superfluidity reappears on further adsorption but at a lower temperature implying that the T_c value of a four-level system should be lower than the T_c value for the three-level system, which is in agreement with the experimental observations.

2 illus, 4 tables, 9 ref

015192   Saikia D;Kumar A (Phys Dep, Tezpur Univ, Napaam, Tezpur, Assam-784 028) : Fast ion transport in P(VDF-HFP)-PMMA-PC-LiCIO₄-TiO₂ composite gel polymer electrolytes. Indian J pure appl Phys 2003, 41(12), 961-6.

Thin films of poly (vinylidene fluoride-co-hexafluoropropylene) P(VDF-HFP) and ploy (methylmethacrylate) PMMA polymer blend elecrolytes plasticized with propylene carbonate (PC) and LiCIO₄ as salt and TiO₂ as inorganic filler have been prepared by solution casting technique. Films of thickness in the range of 30 μm - 1 mm prepared by varying the plasticizer-filler and salt-filler ratio were characterized by aci impedance measurements in the temperature range 293-373 K. Addition of ceramic filler to the polymer electrolyte was found to result in an enhancement of the ionic conductivity. A maximum electrical conductivity of ~2.81x10^-2 S/cm at 293 K and -4.5x10^-2 S/cm at 373 K has been achieved with the dispersion of the TiO₂. Transport number measured by Wagner's polarization method, using silver blocking electrodes, was found to be 0.985. FTIR spectral studies confirmed the formation of polymer-salt complex. XRD patterns exhibit the increased amorphicity in the blended composite gel polymer electrolytes.

4 illus, 1 tables, 30 ref

015191   Ratnakaram Y C;Altaf A;Ravindra Prasad K (Phys Dep, Sri Venkateswara Univ Post Graduate Centre, Kavali-524 201) : Effect of concentration on its optical absorption properties of Pr<. Indian J Phys-Pt A 2004, 78(3), 315-19.

The optical properties of Pr³⁺ doped potassium borate glass in different Pr³⁺ concentrations were studied. From the optical absorption spectra, optical band gaps (E_opt and various spectroscopic parameters (E¹, E², E³ and ξ₄<159>) are determined. Using Judd-Ofelt intensity parameters (Ω₂, Ω₄ and Ω₆), radiative lifetimes (τ_R), branching ratios (β) and integrated absorption cross section (Σ) have been calculated for certain excited states of Pr³⁺ in potassium borate glass for all the concentrations. The radiative lifetimes for all the excited states are minimum when the concentration is high. Few of the transitions have been selected for lasting action from the magnitudes of branching ratios and integrated absorption cross sections.

4 illus, 5 tables, 23 ref

015190   Rajkhowa R;Sarma J K (Phys Dep, Tezpur Univ, Napaam, Tezpur-784 028, Assam) : Particular solutions of GLDAP evolution equations in leading order and structure functions at low-x. Indian J Phys-Pt A 2004, 78(3), 367-75.

Presents particular solutions of singlet and non-singlet Gribov-Lipatov-Dokshitzer-Altarelli-Parisi (GLDAP) evolution equations in leading order (LO) at low-x. Obtains t-evolutions of proton and neutron structure functions and x-evolutions of deuteron structure of functions at low-x from GLDAP evolution equations. The results of t-evolutions are compared with HERA low-x and low Q² data and those of x-evolutions are compared with NMC low-x and low-Q² data.

8 illus, 18 ref

015189   Rajagopal Reddy V;Ramesh C K (Electronics Dep, Univ of Mysore, Postgraduate Centre, Hemagangotri-573 220) : Interfacial reaction and surface morphology of Pd/Re contact schemes to p-type GaN. Indian J pure appl Phys 2004, 42(5), 361-5.

5 illus, 14 ref

015188   Purohit G;Joshi G C (Phys Dep, HNB Garhwal Univ, Srinagar(Garhwal), Uttaranchal-246 174) : Second-order polarizabilities of some quinolines. Indian J pure appl Phys 2003, 41(12), 922-7.

Second order polarizabilities (F128><98>) of some quinolines viz. 8-hydroxyquinoline (8-HQ), 8-aminoquinoline (8-AQ) and 8-hydroxyquinolidine (8-HQD) have been experimentally determined by solvtochromic technique using two-level quantum mechanical model. Comparison has been made with other useful organic molecules and the role of hydrogen bonding has been discussed.

5 illus, 4 tables, 22 ref

015187   Ponnusamy V;Ramasamy V;Dheenathayalu M; Gopalakrishnan M (Phys Dep, Annamalai Univ, Annamalainagar-608 002) : Spurious and regenerated thermoluminescence from natural calcite crystals. Indian J Phys-Pt A 2004, 78(3), 327-30.

The thermostimulated luminescence (TSL) method is employed to study the geologically important tencalcite crystals which were collected from Thalaiyuthu mines, Tirunelveli district, one of the Southern most district of Tamil Nadu, India. The natural thermoluminescence (NTL) glow curve shows the peaks at 260°C and 345°C. In addition to these two peaks, a new peak is appeared at 140°C after irradiation. There is an increase in intensity without change in position and shape of these three peaks when annealed at 400°C. The observation of the spurious thermoluminescence (TL) signal is found to be very different from the other trapping centers. The regenerated thermoluminescence (RTL) equals the intensity of original NTL (345°C) signal during 10th day measurement. After 10th day, there is saturation in intensity.

4 illus, 20 ref

015186   Nayak P K;Rautray T R;Vijayan V (Inst of Phys, , Sachivalaya marg, Bhubaneswar-751 005) : EDXRF: A non-destructive technique for multi-elemental analysis of coins. Indian J pure appl Phys 2004, 42(5), 319-22.

Eleven silver and twenty-five copper coins of British rule (1857-1947 A.D.) have been studied and their elemental compositions have been estimated using non-destructive and simultaneous multi-elemental EDXRF technique in order to verify the effectiveness of this technique for analysis of coins on routine basis. The computer code AXIL was employed to obtain the elemental concentrations from the EDXRF spectra. The obtained results are presented.

3 illus, 1 table, 1o ref

015185   Mohanty R C (Southern Res Inst of Pure and Applied Sci, Southern Univ, Baton Rouge, Lousiana-70813, USA) : The scattering of X-rays and the induction phenomenon. Indian J Phys-Pt A 2004, 78(3), 347-51.

Discusses the well-established Faraday's Law of Induction and the associated Lenz's law and compares these laws with a similar law which appears to exist in the triplet production process achieved by bombardment of emulsion with 0-90 Mev X-rays. This comparision shows that an induction-like process occurs during triplet production, leading to the supposition that a force which may be called the `Matteromotive force' exists for triplet production. An associated Lenz's-law-like law also appears to exist in this process. For this study, 1935 triplets were observed in 54433 fields of view of the microscopes; out of these, 1872 triplets were measured in the energy interval of 2-90 Mev. In addition, the angular distribution of recoil electrons was observed, and is presented.

5 illus, 14 ref