014649   Banerjee F;Chatterjee A;Verma M;Suri A K (Time and Frequency Section, National Physical Laboratory, New Delhi-110 012) : Improvements of Indian standard time at NPL, New Delhi, maintained through GPS network. Indian J Radio Space Phys 2007, 36(1), 20-6.

The National Physical Laboratory (NPL), New Delhi, has been maintaining Universal Coordinated Time (UTC) through GPS network to keep it linked to UTC coordinated by International Bureau of Weights and Measure (BIPM) for more than ten years. Recent measures of housing of cesium clock in a controlled environment, the procurement of new receivers with prior calibration, maintaining the temperature of antenna at a fixed point and the adjustments of required phase and frequency from time to time, have been taken to improve the quality of UTC (NPLI). In view of this, the status of UTC (NPLI) has been studied analytically and exhaustively. The substantial improvement in the performance of the time scale UTC (NPLI) has been observed. This paper elaborates these observations.

6 illus, 2 tables, 7 ref

014648   Balaji Rao R;Srinivasa Reddy M;Yadagiri Reddy P;Veeraiah N (Department of Physics, Acharya Nagarjuna University P.G. Centre, Nuzvid 521 201, Email: nvr8@rediffmail.com) : Dielectric and optical properties-structure correlations in NiO doped Li₂O-MgO-B₂O₃ glasses. Indian J pure appl Phys 2007, 45(3), 243-55.

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

14 illus, 6 tables, 46 ref

014647   Awasthi K;Kulshreshtha V;Tripathi B;Acharya N K;Singh M;Vijay Y K (Physics Dep, University of Rajasthan, Jaipur-302 004, Email: yk_vijay@sancharnet.in) : Transport through track etched polymeric blend membrane. Bull Mater Sci 2006, 29(3), 261-4.

Polymer blends of polycarbonate (PC) and polysulphone (PSF) having thickness, 27 μm, are prepared by solution cast method. The transport properties of pores in a blend membrane are examined. The pores were produced in this membrane by a track etching technique. For this purpose, a thin polymer membrane was penetrated by a single heavy ion of Ni⁷⁺ of 100 MeV, followed by preferential chemical etching of the ion track. Ion permeation measurements show that pores in polymeric membrane are charged or neutralized, which depends upon the variation in concentration of the solvent. The V-I curve at concentration, N/10, shows that the pores are negatively charged, whereas at concentration, N/20, the linear nature of V-I curve indicates that the pores approach towards neutralized state and on further concentration, N/40, the pores become fully neutralized, consequently the rectifier behaviour of pores has been omitted. The gas permeability of hydrogen and carbon dioxide of this membrane was measured with increasing etching time. The permeability was measured from both the sides. Permeability at the front was larger than the permeability at the back which shows asymmetric behaviour of membranes.

3 illus, 12 ref

014646   Anglesky O V;Ushenko A G;Ushenko Y A;Ushenko Y G;Tomka Y Y (NO, Chernivtsi National Univ, 2 Kotsyubinsky Str. Chernivtsi, Ukraine, 58012, Email: ushenko-bio@itf.cv.ukrtel.net) : Polarization correlometry of biological tissue speckle-images and diagnostics of their physiological state III. Polarization-correlation structure of speckle-images of biological tissues birefringernt nets and their pathological changes diagnostics. Asian J Phys 2006, 15(1), 49-54.

3 illus, 3 tables, 2 ref

014645   Angelsky O V;Ushenko A G;Ushenko Y A;Ushenko Y G;Tomka Y Y (NO, Chernivtsi National Univ, 2 Kotsyubinsky Str. Chernivtsi, Ukraine, 58012, Email: ushenko-bio@itf.cv.ukrtel.net) : Polarization correlometry of biological tissue speckle-images and diagnostics of their physiological state II. complex degree of mutual polarization (CDMP) of biological tissue speckle-images. Asian J Phys 2006, 15(1), 41-7.

2 illus, 2 tables, 11 ref

014644   Angelsky O V;Ushenko A G;Ushenko Y A;Ushenko Y G;Tomka Y Y (NO, Chernivtsi National Univ, 2 Kotsyubinsky Str, Chernivtsi, Ukraine, 58012, Email: ushenko-bio@itf.cv.ukrte.net) : Polarization correlometry of biological tissue speckle-images and diagnosis of their physiological state I. Polarization cartography of biological tissues coherent images. Asian J Phys 2006, 15(1), 29-39.

Investigates the statistical polarization and correlation structure of speckle-images of biological tissues with different morphological structure. The paper consists of three parts: first part (I) outlines the results of polarization coordinate mapping and analysis of the statistics of the first-fourth orders of biological tissues polarization azimuth and ellipticities. The second part (II) is directed to study of statistics of the complex degree of mutual polarization of biological tissues speckle-images. In the third part (III) of the paper the diagnostical possibilities of polarization-correlometry of speckle-images which correspond to physiologically normal and degeneratively-dystrophycally changed biological tissues being analyzed.

6 illus, 1 table, 9 ref

014643   Ahmed S F;Das S;Mitra M K;Chattopadhyay K K (Physics Dep, Thin Film & Nanoscience Laboratory, Jadavpur Univ, Kolkata-700 032) : Low-macroscopic field emission from carbon fibers synthesized by direct current plasma enhanced chemical vapour deposition. Indian J pure appl Phys 2006, 44(9), 700-4.

Carbon fibers, in thin film form, have been synthesized on Si substrates via direct current plasma enhanced chemical vapour deposition with acetylene as a precursor using Ni as a catalyst at substrate temperature 750-850°C. X-ray diffraction studies confirmed the graphitic phase of the carbon fibers. Surface morphologies of the films have been studied by a scanning electron microscope and an atomic force microscope. The graphitic carbon fibers have showed good field emission properties with a turn-on field lying in the range 2.57-9.71 V/μm for films deposited with different substrate temperatures. The field enhancement factor and the approximate work function have also been calculated. The emission properties have been studied for different anode-sample spacing for the carbon fibers film deposited at 850°C.

5 illus, 19 ref

013624   Vyas P R;Gohel V B;Bhatt N K;Jani A R (Physics Dep, Gujarat Univ, Ahmedabad-380 009) : High-pressure P-V relation and Gruneisen parameter for elemental strontium. Indian J pure appl Phys 2007, 45(1), 93-5.

The functional relationship among the thermodynamical variables for a system in equilibrium, equation of state (EOS), provides an insight to the dependence of the microscopic internal structure of the material. In this regard, calculated static and dynamic P-V curve for divalent fcc-Sr. Vibrational contribution to the Helmholtz free energy is evaluated within recently proposed mean-field potential (MFP) approximation with the local pseudopotential. Temperature dependence of thermodynamic Gruneisen parameter (γth), a quantity that enters the Mie-Gruneisen form of EOS, is also obtained. Results so obtained are in good agreement with the experimental and other theoretical estimates. Use of present coupling scheme (i.e. MFP + pseudopotential) is thus justified; which has an added benefit of computational simplicity.

2 illus, 7 ref

013623   Venkatathri N (Composite material Center, Korea Institute of Ceramic Engineering & Technology, Seoul-153 801) : Novel synthesis procedure and its characterization of silica nanosphere. Ultra Scient phys Sci 2006, 18(3), 305-10.

Three different procedures are reported for the synthesis of silica nanosphere. In all the method either agglomeration time, addition of hetero atom or use of surfactants plays a vital role. In absence of it give a full fledged crystal. This method is applicable to, irrespect of template, aluminium and silica source. The particles are in nanosphere with size in range from 100 to 500 nm. It is a convenient procedure than the conventional non-aqueous media synthesis.

3 illus, 1 table, 12 ref

013622   Tiwari S N;Mishra M;Shukla R (Physics Dep, DDU Gorakhpur Univ, Gorakhpur-273 009) : Theoretical study of molecular ordering in p-n-hexyloxybenzylidene-p-toluidine: A nematic liquid crystal. Indian J pure appl Phys 2007, 45(1), 83-8.

Anisotropy in the pair potential primarily governs the mesomorphic behaviour of the liquid crystalline molecules. The intermolecular interactions between a pair of HBT molecules have been evaluated using modified second order perturbation treatment along with multicentred-multipole expansion technique. An all valence electron method, CNDO/2, has been employed to compute the net atomic charge and corresponding dipole moments located at each atomic centre of the liquid crystal molecule. Using the results of stacking and in-plane interaction energy studies, probability calculations at varied angular and positional configurations in a molecular pair of HBT, have been carried out using Maxwell-Boltzmann formula. An attempt has been made to elucidate the nematogenic behaviour of p-n-hexyloxybenzylidene-p-toluidine (HBT) molecules.

8 illus, 4 tables, 16 ref

013621   Tiwari R K;Tripathi A (Physics and Electronics Dep, Dr. R.M.L. Avadh Univ, Faizabad-224 001) : Theoretical analysis of antenna gain for a ring micro-strip patch antenna. Ultra Scient phys Sci 2006, 18(3), 409-11.

Investigated the espression of antenna gain for a ring micro-strip antenna and plotted gain vs frequency graph for X-band.

1 illus, 1 table, 4 ref

013620   Thakur A N;Singh U P;Kumar S C;Singh S V (Physics Dep, TDPG College, Jaunpur-222 002) : High temperature electrical conductivity, seebeck coefficient and dielectric constant of ZnMoO4. Ultra Scient phys Sci 2006, 18(3), 355-60.

Report the measurements of electrical conductivity, Seebeck coefficient and dielectric constant of zinc molybdate in the temperature range 300 to 1200K. It is found that the compound is an n-type semiconductor with energy band gap 2.94eV. From electrical conductivity and Seebeck coefficient data, authors estimated the activation energy and charge carrier mobility which show that the conduction is of the normal band type.

3 illus, 12 ref

013619   Suthar S R;Joshi S J;Parekh B B;Joshi M J (Crystal Growth Laboratory, Physics Dep, Saurashtra Univ, Rajkot-360 005) : Dielectric study of Cu<. Indian J pure appl Phys 2007, 45(1), 48-51.

Calcium tartrate crystals are well-known for their ferroelectric propertias. In the present study, copper doped calcium tartrate tertrahydrate crystals were grown by the single diffusion gel growth technique. The amount of copper doping was confirmed by Induced Condensed Plasma (ICP). The single phase nature was identified by powder XRD. The dielectric measurements were made on pelletized samples in the temperature range 40-160°C and the frequency range 1- 500 kHz. The dielectric constant was determined from the value of capacitance. The copper doping showed significant influence on the value of dielectric constant and the transition temperature.

4 illus, 1 table, 12 ref

013618   Srivastava V;Sanyal S P;Rajagopalan M (Physics Dep, Barkatullah Univ, Bhopal-462 026, Email: spsanyal@sancharnet.in) : Ab-initio calculation and B₁ to B₂ structural phase transformation in CdO at high pressure. Indian J pure appl Phys 2007, 45(1), 75-8.

The electronic and structural properties of CdO at high pressure have been studied by using the self-consistent tight binding linear muffin tin orbital method. The relative stabilities of CdO at high pressure in the rock salt and CsCl structures have been examined. The rock-salt structure is found to be the ground state structure of CdO. The phase transition from NaCl (B₁)- to CsCl (B₂)-type structure for CdO is found to occur at 81.7 GPa, which is close to experimental value 90.6 GPa. Calculated lattice parameter and bulk modulus in both the phases are in good agreement with experimental results. The calculated band structure shows a small overlap between the conduction and valence bands with a direct band-gap of <126> 1.37 eV. A broadening of the upper Cd-4d and O-2p bands with some intermixing between them is observed in total DOS histogram of CdO.

2 illus, 2 tables, 14 ref

013617   Sinha M M (Physics Dep, Sant Longowal Institute of Engineering and Technology, Longowal, Distt. Sangrur, Punjab-148 106) : Phonons in non-oxide perovskite superconductor MgCNi₃. Indian J pure appl Phys 2007, 45(1), 72-4.

The new intermetallic non-oxide perovskite superconductor MgCNi₃ was discovered by He et al, Nature, 411(2001) 54, following on from the breakthrough of the finding of the MgB₂ superconductor at the beginning of 2001. MgB₂ has subsequently been intensively studied; however, less attention has been paid to MgCNi₃ due to its much lower superconducting transition temperature (T_c <126> 8 K), as compared to that of MgB₂ (T_c <126> 39 K). But it has many interesting properties, which need to be focused on to obtain an understanding of its complicated physics. Being a perovskite superconductor like Ba_1-x, KxBiO₃ and cuprate superconductors, MgCNi₃ is special it is neither an oxide nor does it contains, any copper. Meanwhile, MgCNi₃ can be regarded as fcc Ni with only one quarter of Ni replaced by Mg and with C sitting on the octahedral sites. The fact that superconductivity rather than ferromagnetism occurs in a compound where so much nickel is present is surprising and suggest that MgCNi₃ is a candidate for exhibiting unconventional superconductivity. In this work, a de Launey angular force constant model has been used to study the phonons in MgCNi₃. The phonon dispersion curves in the symmetric directions are plotted and compared with available results.

2 illus, 2 tables, 16 ref

013616   Sinha K P;Meulenberg A (Physics Dep, Indian Institute of Science, Bangalore-560 012) : Laser stimulation of low-energy nuclear reactions in deuterated palladium. Curr Sci 2006, 91(7), 907-12.

Models to account for the observed experimental results for low-energy nuclear reactions in palladium-deuteride systems are presented along with calculated results. The crucial idea is a mechanism of improved, probability for the needed penetration of the Coulomb barrier for a D-D reaction. This facilitation occurs, in general, with the formation of D ions at special frequency modes (e.g. via phonons) and, specifically for the laser-stimulated case, with utilization of enhanced optical potential at a selected interface. Both mechanisms may work individually, or together, to increase the probability of barrier penetration.

3 illus, 12 ref

013615   Singh Y P;Singh R A (Physics Dep, Govt. Women's Polytechnic College, Sagar, Email: Y_P_S_2k@Yahoo.com) : Force fields and vibrations for anisole and its nitro-substitutent molecules. Ultra Scient phys Sci 2006, 18(3), 273-80.

Normal coordinate calculations for the Anisole, o-nitro anisole,m-nitro anisole and p-nitro anisole have been performed. Assuming Cs point symmetry, normal modes of vibrations were calculated. Also deals with the force field calculations for the planar and non-palnar vibrational modes of investigated molecules. A general valence force field consisting of 51 force constants for the investigated molecules have been determined. Reinvestigates the vibrational spectra of these molecules and unique feature of the study is the determination of a single set of force constants to reproduce the vibrational frequencies for all the investigated molecules.

4 illus, 2 tables, 15 ref

013614   Singh N;Saini S M;Nautiyal T;Auluck S (Physics Dep, Indian Institute of Technology Roorkee, Roorkee-247 667) : Optical properties of CeSb and LaSb. Indian J pure appl Phys 2007, 45(1), 69-71.

The calculations of the electronic and the optical properties of CeSb and LaSb, using the full potential augmented plane wave (FP-LAPW) method including spin orbit coupling within local spin density (LSDA) approximation as implemented in WIEN2K code have been performed. The reflectivity and the real part of the optical conductivity of CeSb and LaSb have been calculated. The real part of the optical conductivity of these compounds is deduced from Kramers-Kronig transformation. The calculated spectra of the real part of the optical conductivity and reflectivity of LaSb and CeSb are in the agreement with the available experimental data. The calculations have given the value of specific heat constant of CeSb and LaSb 23.4 mJmo^-1-1K^-2 and 0.37 mJmol^-1 K^-2, respectively, which are very close to experimental value.

1 illus, 14 ref

013613   Singh G S;Bajpai R P (Advanced Optical Processing Central Scientific Instruments Organizatio, , Secter 30, Chandigarh- 160 030, Email: gssingh55@yahoo.com) : Design consideration of two components machenically compensated zoom lenses. J Optics 2006, 35(1), 18-35.

Describes a simple method developed to solve the problem of determining the kinematics of two-component mechanically compensated zoom lenses. It has been Shown that a simple paraxial conjugate equation, along with magnification equation-can be used successfully to solve the complex problem of component displacement in a two components mechanically compensated zoom lens. This method provides a deep insight into the image formation process by a zoom lens. The method developed is simple to program and provide excellent information about working of two-component mechanically compensated zoom lenses.

5 illus, 14 tables, 15 ref

013612   Singh G S;Bajpai R P (NO, Advanced Optical Processing Central Scientific Instruments Organizatio, Secter 30, Chandigarh-160 030, Email: gssingh55@yahoo.com) : Design consideration of three components machenically compensated zoom lenses. J Optics 2006, 35(1), 1-17.

Presents a simple method to determine the power and air space distribution for three component mechanically compensated zoom lens. Also describes a method developed to solve the complex problem of kinematics determination of three-component mechanically compensated zoom lenses. It has been shown that a simple paraxial conjugate equation, along with magnification equation can be used successfully to solve the problem of component displacement in a three component mechanically compensated zoom lens. This method provides a deep in sight into the image formation process by a zoom lens.

5 illus, 7 tables, 13 ref

013611   Shukla D K;Mollah S (Physics Dep, Aligarh Muslim Univ, Aligarh-202 002, Email: smollah@rediffmail.com) : dc Conductivity and dielectric properties of V₂O₅-Bi₂O₃-ZnO glass. Indian J pure appl Phys 2007, 45(1), 52-6.

Semiconducting oxide glass with composition 40V₂O₅-40Bi₂O₃-20ZnO is prepared by rapid quenching method. The glassy phase is confirmed from X-ray diffraction (XRD) pattern which shows a broad hump around 20 = 30°. The dc conductivity of the glass has been measured in the temperature range 300 - 600 K and compared with that of other vanadium and copper based zinc oxide containing glasses. The dc conductivity is due to non-adiabatic small polaron hopping conduction which is confirmed from the fitting of the conductivity data with different polaronic hopping models. The frequency (75 kHz - 30 MHz) dependent dielectric constant of the glass decreases first and then increases with the increase of frequency at room temperature. The anomaly in frequency dependent dielectric constant at <126> 5 MHz may be due to the displacement and/or orientational motion of BiO₃ and BiO₆ structural units present in the glass.

4 illus, 1 table, 26 ref

013610   Sharma S K;Ravi Kumar;Siva Kumar V V;Dolia S N;Gupta A;Reddy V R;Knobel M;Singh M (Physics Dep, H P Univ, Shimla-171 005, Email: skumar275@rediffmail.com) : Size dependent magnetic behaviour of nanocrystalline spinel ferrite Mg_0.95Mn_0.05Fe₂O₄. Indian J pure appl Phys 2007, 45(1), 16-20.

Mg_0.95Mn_0.05Fe₂O₄ ferrite nanoparticles having dimensions varying from 4.7-12 nm, have been synthesized by using solid-state reaction technique followed by high-energy ball milling for different times. An X-ray diffraction study indicates the presence of single-phase cubic spinel structure. The particle sizes were estimated from the X-ray line broadening of the (311) reflection using Debye-Scherrer's formula. The size-dependent magnetic properties of Mg_0.05Fe₂O₄ nanoparticles were studied using SQUID magnetometry techniques. The saturation magnetization Ms at 5 K obtained by extrapolating M versus l/H plot to1/H = 0 were decreased with the decrease in the particle size. The coercive force of the nanoparticles has a clear size-dependence below the blocking temperature. The calculated anisotropy constant was found to be rather large for nanoparticle samples. All these results can be explained on the basis of single-domain superparamagnetic effects.

5 illus, 15 ref

013609   Shalendra Kumar;Ravi Kumar;Reddy V R;Banerjee A;Alimuddin (Applied Physics Dep, Aligarh Muslim Univ, Aligarh-202 002) : Multiferroic behaviour of Ti doped Mg_0.95Mn_0.05Fe₂O_4. Indian J pure appl Phys 2007, 45(1), 31-6.

Multiferroic behaviour of Ti doped Mg_0.95gsMn_0.05Fe₂O has been studied using X-yay diffraction, isothermal magnetization hysteresis, dc magnetization and dielectric measurements. X-ray diffraction analysis shows a structural transformation from cubic spinel to tetragonal. On the other hand, the presence of paramagnetic doublet within the sextet shows the presence of electric field gradient (EFG) due the structural transformation. Isothermal hysteresis loop shows ferromagnetic behaviour of Mg_0.95Mn_0.05Fe_2-2XTi_2xO₄ and decrease in saturation magnetization with increase in the substitution of the Ti⁺⁴. The decrease in the saturation magnetization is due to the dilution of the sublattice by the non-magnetic Ti⁺⁴ ions and which is explained by the weakening of exchange interaction in the system. The dc magnetization shows that the Curie temperature is decreasing with increasing in the substitution of non-magnetic ions. The presence of the peak in the dielectric constant measured as a function of temperature at 100 kHz indicates the presence of ferroelectric transition in the materials.

4 illus, 1 table, 19 ref

013608   Shah N A;Rather M F (Department of Electronics & Instrumentation Technology, University of Kashmir, Srinagar-190 006, Email: farsgr@yahoo.co.in) : Voltage-mode OTA-based active-C universal filter and its transformation into CFA-based RC-filter. Indian J pure appl Phys 2006, 44(5), 402-6.

An absolute minimum component voltage-mode (VM) universal filter, employing two each of operational transconductance amplifiers (OTAs) and capacitors with three inputs and one output, is presented. The circuit can be transformed into CFA-based RC-filter involving two each of current feedback amplifiers (CFAs), capacitors and resistors. OTA-C circuit enjoys electronic tunability of filtedring parameters while its CFA-based RC version offers low output impedance which suits cascadability. PSPICE simulation and the experimental results of both the circuits are included.

7 illus, 22 ref

013607   Saroa M S (NO, Haldia Institute of Technology, Haldia, West Bengal) : Flow of non-newtonian fluids between rotating disks. Proc Indian Natn Sci Acad 2006, 72(3), 121-4.

Flow of incompressible second - order fluids between two parallel disks rotating with different constant angular veloctfies about different axes has been discussed. A one-parameter sulution of the problem has been obtained. The force on a disk has been calculated to determine the material constants.

5 ref

013606   Saini S M;Singh N;Nautiyal T;Auluck S (Physics Dep, Indian Institute of Technology Roorkee, Roorkee-247 667) : Reflectance and magneto-optical Kerr rotation in DyP. Indian J pure appl Phys 2007, 45(1), 66-8.

The rare-earth compounds are distinguished by their unique magnetic, electric and optical properties. These are strongly correlated materials. Their highly localized 4f electrons are responsible for their large magnetic moment. Optical properties of a material can be utilized in different applications such as reflectors, filters, and X-ray masks. On the other hand, magneto-optical properties of materials are used in storage devices. The calculations of optical properties of rare-earth compound DyP using the full potential linear augmented plane wave (FPLAPW) method with inclusion of spin orbit coupling have been reported. The Coulomb-corrected local spin density approximation, i.e. LSDA+U, which is known to treat the highly correlated 4f electrons properly have been employed. The calculated optical properties are in good agreement with the measured value. The magneto-optical Kerr- rotation has been reported and the values expected for DyP in the low energy range have been predicted.

4 illus, 8 ref

013605   Rawat D;Khan I A;Singh S (Physics Dep, Saifia P.G.College of Science and Education, Bhopal-462 001) : Cohesive energies in ammonium halides (NH₄Cl, NH₄Cl_1-xBr_x. Ultra Scient phys Sci 2006, 18(3), 406-8.

The three body potential (TBP) model applied to explain the cohesive properties of (NH₄Cl, NH₄Cl_1-x Br_x) and the associated volume collapse. The charge transfer effects, arising from the overlapping or deformation of the electron shells of the adjacent ions leading to the many body's interactions are included explicitly in the crystal potential. The present TBP calculations of cohesive energies are in good agreement with experimental data.

2 tables, 18 ref

013604   Raj Kumar;Upadhyay M;Shukla S R;Pandey D N (Physics & Electronics Dep, Dr. R.M.L. Avadh Univ, Faizabad) : Dielectric constant for <60>100<62> tunneling model by applying the electric field in <60>100<62>,<60>110<62> & <60>111<62> crystallographic directions. Ultra Scient phys Sci 2006, 18(3), 401-4.

Investigated theroetically the variation of dielectric constant with respect to temperature for <60>100<62> tunneling model by applying electric field in <60>100<62>, <60>100<62> & <60>111<62> directions with k=1.38x10^-23 J/K, N=4x10²⁵ m^-3 & 4 x 10²⁶ m^-3, μ=3 Debye for temperature range from 10 K to 300 K which may be used to explains various experimentally available data and may be also used for further theoretical investigations.

1 illus, 7 ref

013603   Qureshi N M;Gautam V K;Tiwari S;Agrawal R C (Physics Dep, Govt. P.G. College Balaghat, ) : Electrical characterization of inorganic ACTFEL devices via spice. Ultra Scient phys Sci 2006, 18(3), 387-92.

Inorganic ACTFEL (Alternating current thin film Electro-luminescence) devices are complex optoelectronic display devices. Presents the electrical characterization of space charge of ZnS:Mn phosphor via both SPICE two sheet and SPICE Fowler-Nordheim diode. Simulation results show that both models are capable of explaining the electrical characterization of the phosphor.

8 illus, 11 ref

013602   Qureshi A;Singh N L;Somani K;Rakshit A K; Singh F;Avasthi D K (Physics Dep, M S Univ of Baroda, Vadodara-390 002) : Ion bean modification and analysis of polymer composites. Indian J pure appl Phys 2007, 45(1), 57-61.

Thin films of ferric oxalate dispersed in polyvinyl chloride (PVC) were synthesized. Ferric oxalate was dispersed in PVC films at various concentrations. These films were irradiated with 80MeV O⁶⁺ ions at a fluence of 1x 10¹¹ ions/cm².The radiation induced changes in dielectric properties, microhardness and surface roughness have been studied. It has been observed that hardness and dielectric properties of the film increase with the concentration of dispersed ferric oxalate and also with the fluence. This suggests that ion beam irradiation promotes the metal to polymer adhesion, and converts the polymeric structure into hydrogen depleted carbon network, which make polymer harder and more conductive. Atomic force microscopy shows that the average roughness of the irradiated films is lower than that of un-irradiated films.

5 illus, 9 ref

013601   Patil R R;Moharil S V;Dhopte S M;Muthal P L; Kondawar V K (Department of Physics, Institute of Science, Nagpur-440 001) : Photoluminescence of Cu<. Indian J pure appl Phys 2006, 44(5), 375-7.

Using the reactive atmosphere processing, Cu⁺ has been doped in double sulphates for the first time. Photoluminescence of Cu⁺ in double sulphates in reported. The results establish that it is now possible to incorporate Cu⁺ in double sulphates. This opens up new, exciting possibilities of studying photoluminescence vis-a-vis sequence of phase transtitions.

3 illus, 27 ref

013600   Parveen Kumar;Tiwari J P;Shahi K (Solid State Ionic Laboratory, Advanced Center for Materials Sciences, Indian Institute of Technology Kanpur, Kanpur-208 016) : Ion transport study of mechanically-milled amorphous AgI-Ag₂O-V₂O-V₂O₅ fast ionic conductors. Indian J pure appl Phys 2007, 45(1), 44-7.

The structural and electrical characterizations of mechanically-milled (MM) amorphous fast ionic conductors (a-FICs), viz. xAgI (100-x)[0.67 Ag₂O-0.33V₂O₅] (x = 40, 50, 55 and 70 ) have bean reported. The amorphisation is restricted only to the compositions which are well within the glass forming region and all samples are found to be highly agglomerated and X-ray amorphous in nature. The frequency dependent ac conductivity, σ'(ω), of the amorphous samples investigated in the frequency range 5Hz -13 MHz and temperature range 100- 350 K shows a dc conductivity regime at low frequencies and a dispersive regime at higher frequencies. The σ'(ω) spectra can be described by the Jonscher power law (JPL), σ'(ω) = σ_dc> + A(T)ωⁿ. However, the values σ_dc(T) and A(T) both show two distinct Arrhenius regions and n (<60> 1 ) is found to be temperature dependent, i.e., decreasing with increasing temperature.

6 illus, 2 tables, 18 ref

013599   Pandya A;Jha P K (Computational Condensed Matter Physics Laboratory, Physics Dep, Facult, The M S Univ of Baroda, Vadodara-390 002) : Phonon interaction and variation of deformation potential with temperature and concentration in diluted Ga(_{1-X) MnXN quantum well.} Indian J pure appl Phys 2007, 45(1), 96-9.

The carrier transport properties for two dimensional diluted Ga_(1-x)Mn_xN have been calculated via electron acoustical phonon interaction on the basis of deformation potential coupling mechanism for the different concentrations of Mn (x ≤10%) at different temperatures. The acoustic phonon scattering rate increases with the energy and decreases with the manganese concentration. The contribution of acoustic phonons in the variation of resistivity for different manganese concentrations and threshold thermal energy have also been determined. The temperature and concentration both affect the acoustic phonon scattering rate. Therefore, the resistivity varies due to the effect of these on the acoustical deformation potential (ADP).

4 illus, 1 table, 7 ref

013598   Ojha P K;Singh S P;Upadhyaya K S (Physics Dep, K N Govt PG College, Gyanpur, SRN Bhadohi, U.P) : Phonon dispersion curves of TiN. Indian J pure appl Phys 2007, 45(1), 79-82.

A lattice dynamical model which includes the effect of three-body interactions (TBI) in the framework of second neighbour rigid shell model (SNTRSM) and second neighbour rigid ion model (SNTRIM) has been developed. The models, thus obtained, have been applied to study the phonon dispersion curves (PDCs) of TiN along the principal symmetry directions. It is found that SNTRSM explains well the phonon anomalies in the experimental PDCs of TiN as compared to SNTRIM and other models.

1 illus, 2 tables, 10 ref

013597   Nagaraja K;Prasad B S N;Chandrashekara M S; Paramesh L;Madhava M S (Department of Studies in Physics, University of Mysore, Mysore-570 006) : Inhalation dose due to radon and its progeny at Pune. Indian J pure appl Phys 2006, 44(5), 353-9.

The radon and its progeny concentrations are measured near the surface of the earth at the Indian Institute of Tropical Meteorology, Pune, India. In-situ measurements of the meteorological parameters such as temperature and relative humidity are also made simultaneously. The concentrations show maxima in the early morning hours when the turbulence mixing is the minimum; whereas in the afternoon the turbulence mixing is the maximum and concentrations exhibit minima. The diurnal and seasonal variations in the concentrations of radon and its progeny are found to exhibit correlation with the relative humidity, and anti-correlation with the temperature. The annual effective dose for Pune environment is found to be 0.55 mSv which is within the permissible limit.

5 illus, 40 ref

013596   Mohanty B (Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700 064, Email: bmohanty@veccal.ernet.in) : Results from the relativistic heavy ion collider. Proc Indian Natn Sci Acad 2006, 72(3), 153-8.

Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is the only dedicated machine for research in the field of high energy heavy-ion collisions. Four experiments namely BRAHMS, PHOBOS, PHENIX and STAR, use this facility to study the properties of matter formed when two heavy ions collide at very high center of mass energies. A lot of interesting data have come out of RHIC experiments, which suggest formation of a hot and dense matter in the heavy ion collisions, which is one of the pre-requisite of quark gluon plasma (QGP) formation. Authors discuss the recent important results from the four experiments. Results based on identified particle production and particle ratio, strange particle enhancement, suppression of hadron production at high transverse momentum relative to nucleon-nucleon collisions, azimuthal flow, direct photon and J/ρ ψ production are presented.

10 illus, 17 ref

013595   Mazumder D P (NO, University of Alaska Fairbanks, Geophysical Institute, 903 Koynkuk Drive, P.O. Box-752 963, Fairbanks, Alaska 99775, USA, Email: debasish@gi.alaska.edu) : On the kinetic energy spectra of turbulence in the thermally stratified atmospheric surface layer. Proc Indian Natn Sci Acad 2006, 72(3), 125-33.

Turbulence energy spectra in a thermally stratified turbulent shear flow are determined by solving the spectral equation -for turbulent kinetic energy budget in a simplified framework. A brief account of the Monin-Obukhov similarity theory, as appropriate for the description of such a turbulent flow is given. Following the classical statistical approach to the turbulent flow, the equation for the turbulent kinetic energy budget in the physical space and its version in the wave number space are derived in a straightforward manner. The closure of the spectral equation is achieved through the modeling of the terms describing production of the turbulent kinetic energy from the mean velocity shear, energy transfer through hierarchy of the eddies and the contribution of the buoyancy forces towards turbulent kinetic energy. A complete solution for the three-dimensional energy spectrum and the two one-dimensional energy spectra corresponding to the turbulent velocity components in the horizontal and vertical directions are obtained. All these spectra are evaluated, with the data from well known simulated experiment on the stably stratified atmospheric boundary layer in a meteorological wind tunnel. The behaviour of these spectra over a wide range of wave numbers, which includes both inertial and dissipation ranges, is discussed.

5 illus, 23 ref

013594   Kushwaha A K;Shankar G;Kushwaha S S (Physics Dep, Bundelkhand University, Jhansi-284 128, Email: akkphys_bu@yahoo.com ) : Lattice dynamical calculations of spinel structure compounds. Indian J pure appl Phys 2006, 44(5), 85-90.

Lattice dynamical calculations have been performed for normal spinel structure compounds using the proposed theoretical model. In this model, the dynamical matrix is split into two parts: (i) the short range part is evaluated by using Taylor's expansion of the crystal potential energy in the harmonic approximation and (ii) the long range part is evaluated on the basis of screened Coulomb potential. this model is applied to study the zone centre (Γ=0) phonon frequencies of sulphide spinels MCr₂S₄(M= Mn, Fe, Cd). The significant outcome of the present work is that (i) the tetrahedral M-S force constants are smaller than the respective octahedral (Cr-S) ones, (ii) the bending force constants are negligible, and (iii) the effective dynamical charges of the bivalent metal ions are nearly zero. The zone-centre phonon frequencies, thus calculated using these parameters are found to be in very good agreement with the observed results.

4 illus, 3 tables, 18 ref

013593   Kumar P;Pal K;Gupta G K (Department of Physics, D.B.S.College, Dehradun-248 001, Uttarnchal) : High input impedance all-pass and notch filter configuration. Indian J pure appl Phys 2006, 44(5), 398-401.

A circuit realizing second order all-pass and notch filter, employing current conveyors and operational amplifier/CFA as the active circuit elements is proposed. the circuit uses only two current conveyors, one operational amplifier/current feedback amplifier, four resistors and two grounded capacitors. The current conveyors used in the circuit are replaceable by translinear current conveyors and thus quality factors Q and center frequency become controllable through the bias currents of the translinear current conveyors. the filter also displays low incremental parameter sensitivities. The simulation results on the filter support theory.

4 illus, 14 ref

013592   Joshi U S;Koinuma H (Physics Dep, School of Sciences, Gujarat Univ, Ahmedabad-380 009) : Binary composition spread approach for parallel pulsed laser deposition synthesis and highthroughput characterization of transparent and semiconducting oxide thin films. Indian J pure appl Phys 2007, 45(1), 62-5.

Conventional 'one by one' synthesis approach has been a major rate limiting step in the systematic exploration of increasingly complex materials for the demanding new technologies. Derived from the new concepts of combinatorial chemistry, recently introduced continuous binary composition spread technique based on the non-uniformity of the deposition rate typically observed in pulsed laser deposition (PLD) is applied to the parallel growth of transparent and semiconducting oxides Li_xNi_1-xO. A large variation of x in Li_xNi_1-xO was achieved on a single MgO(100) substrate. Details of the synthesis technique are discussed. Microstructural, transport and optical studies were done to optimize the Li concentration in the film. XRD and AFM confirmed an epitaxial growth and smooth surface for all the Li contents. SIMS data revealed a non-linear Li variation along the film with a minimum of 0.01% of Li content. High conductivity of 1.42 ohm^-1 cm^-1 was obtained in sufficiently high Li concentration regions. Optical transparency beyond 80% was obtained in the 40 nm thick films. The combinatorial binary composition spread technique results in significant time and energy savings for rapidly optimizing the thin film growth parameters to explore new TCOs for future optoelectronic applications.

5 illus, 12 ref

013591   Joshi P B;Rao V J;Rehani B R;Arun Pratap (Metallurgical Engineering Dep, M S Univ of Baroda, Vadodara-390 001) : Silver-zinc oxide electrical contact materials by mechanochemical synthesis route. Indian J pure appl Phys 2007, 45(1), 9-15.

Mechanochemical synthesis or reactive milling (RM) is a well-established high-energy milling process for production of a wide range of nanocomposite powders using oxides, carbonates, sulphates or hydroxides as the starting precursors. It ensures chemical reactions such as oxidation/reduction, decomposition or phase transformation in solid-state conditions during room temperature milling, which otherwise require high temperatures. The silver-zinc oxide nanocomposite powders by reactive milling of silver oxide and zinc powder particles have been produced. The resultant Ag-ZnO nanocomposite powders are further processed to bulk solid pieces by conventional powder metallurgy route as electrical contact materials for switchgear applications.

4 illus, 2 tables, 17 ref

013590   Himanshu A K;gupta D C;Sinha T P (School of Studies in Physics, Jiwaji University, Gwalior-474 011) : Dielectric study of Ba(Zn_{1/3Nb2/3)O3 at low temperature.} Indian J pure appl Phys 2006, 44(5), 391-7.

The dielectric study of Ba(Zn_1/3Nb_{2/3)O3 has been studied at low temperature in a frequency range 100 Hz-1 MHz and a temperature range from 145K to room temperature. An analysis of real and imaginary part of dielectric permittivity, impedance (Z), conductivity and electric modulus with frequency and temperature is performed, showing the polydispersive nature of the relaxation time in the sample as confirmed by the Cole-Cole plot of the dielectric permittivity and impedance. All these results suggest that the relaxation phenomenon seen in the configuration has been attributable to the damping of dipole oscillators due to the application of the external fields.}

7 illus, 16 ref

013589   Haghighi B;Maaleki H;Shakhs Emampour S J (Thermodynamic &Transport Properties Research Laboratory (T&TPRL), Dep, Birjand University, 97175-615, Birjand, Southern Khorasan Province, Iran) : Non-equilibrium ensemble method: A quantum-statistical-mechanical approach. Indian J pure appl Phys 2006, 44(5), 378-84.

The non-equilibrium ensembles method has been applied to Boltzmann quantum-kinetic equation. The author used the quantum-kinetic equation governing the density matrix, which has been proposed by Ogul and Eren, J Chem Phys, 105 (1996) 7664. The non-equilibrium quantum-mechanical ensemble can be constructed in terms of non-equilibrium entropy, Boltzmann entropy, constrained by the quantum Boltzmann equation as a dynamical equation of motion, which has governed the time evolution of non-equilibrium density matrix. The quantum-mechanically non-equilibrium partition function has been obtained. The conjuncture with the traditional irreversible thermodynamics has been shown.

90 ref

013588   Gunasekaran S;Seshadri S;Muthu S (PG & Research Department of Physics, Pachaiyappa's College, Chennai-600 030) : FTIR, FT Raman spectra and normal coordinate analysis of hydralazine. Indian J pure appl Phys 2006, 44(5), 360-6.

Hydralazine (C₈H₈N₄.HC1) is chemically known as 1-hydrazinophthalazine mono hydrochloride. It is used as an anti-hypertensive agent. In the present investigation, normal coordinate analysis has been carried out for the molecule of the title compound using fundamental modes of vibration observed in infrared and Raman spectoscopy. The vibrational modes are classified into A' and A" irreducible representation and are distributed asΓ_vib=35 A'+19 A" based on C_s point group symmetry associated with the structures. In the present work, only 18 A' adn 12 A" normal modes are considered due to complexity of the molecule. A systematic set of orthonormal symmetry co-ordinates has been constructed. Wilson's F-G matrix method has been adopted for the normal coordinate analysis. A satisfactory vibrational band assignment has been made by using the FTIR and FT Raman spectra of the compounds.

3 illus, 2 tables, 17 ref

013587   Ganguly P;Biswas J C;Lahiri S K (Integrated Optics Laboratory, Advanced Technology Centre, Indian Institute of Technology, Kharagpur- 721 302, Email: pran@ece.iitkgp.ernet.in) : Design of single mode annealed proton exchanged LiNbO3 waveguides by effective-index based matrix method. J Optics 2006, 35(1), 51-62.

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

5 illus, 1 table, 22 ref

013586   Ganesan M;Sharma N K;Jain V K (NO, Central Scientific Instruments Organisation (Delhi Centre), CSIR Complex, Pusa Campus, New Delhi) : Optimization of polymer coated silicon microcantilever for chemical sensing applications. Indian J pure appl Phys 2006, 44(5), 407-13.

The mechanical design and optimization of polymer coated silicon microcantilever (MC) for chemical sensing application have been studied through simple mass sensitivity factor.For this theoretical modeling, silicon is the base layer (substrate) and the functional layer can be selected according to the chemical detection. The mass sensitivity factor and spring constant change before and after chemical reactions have been analyzed theoretically by taking minimum of four hundred samples in each case study. Finally, the specific dimensions and guidelines for designing high sensitivity polymer coated microcantilever for chemical sensing application based on the case study have been suggested. The optimized microcantilever is theoretically analyzed with detection of water vapour and primary alcohols.

11 illus, 4 tables, 9 ref

013585   Gajjar P N;Mishra S R;Jani A R (Physics Dep, Univ School of Sciences, Gujarat Univ, Ahmedabad-380 009) : Variation of electrical resistivity with temperature of liquid tenary alloys of Na-K-Rb. Indian J pure appl Phys 2007, 45(1), 89-92.

A model potential and Ziman formulation is employed to study the temperature sensitiveness of electrical resistivity of liquid ternary alloys of Na-K-Rb. The calculated structure factors and form factors are employed for the numerical investigation of electrical resistivity for temperatures in the range 100-500°C. The binary combinations Na-K, Na-Rb show the Nordheim parabola for increasing temperatures, but there is an exception to K-Rb alloy system. The good agreement for electrical resistivity for pure liquid metals and their binary combination is achieved. The results of electrical resistivity for the ternary combination Na-K-Rb rise with temperatures.

1 illus, 2 tables, 16 ref

013584   EL-BATA FH;Fayad AM;EL-Rahman SA;Moustaffa FA (Glass Research Department, National Research Centre, Dokki, Cairo, Egypt) : Effect of divalent metal oxides on absorption spectra of some sodium borate glasses containing mixed nickel and iron oxides. Indian J pure appl Phys 2006, 44(5), 367-74.

Absorption spectra of nickel and iron ions in some sodium borate glasses containing magnesia, cadmium oxide, zinc oxide, lime, strontium oxide or barium oxide were carried out to study the structure of these glasses and the effect of divalent metal oxides on the glass structure. Nickel usually exists in glass as divalent nickel ions in two different forms, octahedral (NiO₆) and tetrahedral (NiO₄), while iron usually exists in glass as ferrous and ferric states in two different forms, octahedral and tetrahedral according to the glass composition. The states of the transition metal ions in the the glasses depend on several factors such as: (i) the polarizability of the oxygen ligands surrounding the transition metal ion; (ii)the mobility of the alkali ions and their field strengths and (iii) the opportunity of forming network units such as MO₄ for some of the divalent metal oxides.

6 illus, 2 tables, 27 ref

013583   Bose P (NO, Govt. Arts and Science College, Durg(C.G.)-490 001) : Opto-electrical studies of rare earth doped (Cd-Pb)S films. Ultra Scient phys Sci 2006, 18(3), 375-80.

Reports some interesting observations on photoconductivity studies of different (Cd-Pb)S films prepared by simple techniques. The high gain (I_pc/I_dc ratio) observed for such materials show potential for future applications. Results of photoconductivity rise and decay, optical absorption and photoconductivity excitation spectra, XRD and SEM are presented for different (Cd-Pb)S films. The ratio of saturated photocurrent of rise curves (Ipc) to dark current (Idc) is found to be of the order of 10⁵ for (Cd_0.95-Pb_0.05)S films. Band gaps determined from the optical absorptions and photoconductivity excitation spectra gave similar results. The direct band gap nature is found for mixed films. From the XRD studies a combination of cubic and hexagonal structure are found. Lattice constants calculated from XRD studies agree well with the standard data. The SEM studies show growth of cabbage and leafy structures.

6 illus, 4 tables, 11 ref

013582   Bodhaye A;Sanyal S P;Okram G S;Mukovskii Y M (Physics Dep, Barkatullah Univ, Bhopal-462 026) : Transport, magnetic and thermal properties of La_0.88Ca_0.12MnO₃ single crystal. Indian J pure appl Phys 2007, 45(1), 37-9.

The transport, magnetic and thermal properties of La_{0.88 Ca0.12 MnO3 single crystals have been studied using various experimental techniques. The resistivity measurement shows the characteristics of semiconducting behaviour having the resistivity 6.9 MΩcm at 90K and 31.5 Ωcm at 296K. There is no resistivity peak or electronic transition over the whole temperature range studied. However, there is a potable change of resistivity at about 115 K, seemingly related to paramagnetic insulator to ferromagnetic insulator transition. The ac susceptibility measurement confirms that this material shows paramagnetic insulator to ferromagnetic insulator transition with Tc = 117.5 K. The sharp peak around the same temperature in the heat capacity measurement indicates the onset of long range ordering.}

3 illus, 8 ref