014300   Subramanyam Naidu R;Ravindra Prasad K (Dep of Phys, SVU PG Cent, Kavali-524 201) : Molecular interactions in the binary mixtures of fenvalerate. J pure appl Ultrasonics 2005, 27(1), 15-24.

The ultrasonic behaviour of the ester, fenvalerate has been studied in the solvents, methanol and xylene at different temperatures in the range 30-50°C. Acoustical and other related parameters like compressibility, internal pressure, free volume, free length etc. have been computed from the experimentally measured velocity, density and viscosity data. Salvation numbers, apparent molar compressibility and apparent molar volume have been evaluated and analysed in the light of solute-solvent-and solute-solute interactions. In the solutions of fenvalerate with xylene, solute-solute interactions appear to be dominant while in fenvalerate + methanol system, strong solute-solvent interactions are indicated predominantly.

12 illus, 3 tables, 21 ref

014299   Subrahrnanyam N;Rajagopal E;Murthy N M (Dep of Phys, Sri Krishnadevaraya Univ, Anantapur-515 003, Email: nmanoharamurthy@yahoo.co.in) : Studies on the temperature dependence of lattice energies of alkali chlorides, bromides and iodides. Indian J Phys 2005, 79(10), 1169-72.

Lattice energies of LiCl, NaCl, KC1, RbCl, LiBr, NaBr, KBr, RbBr, CsBr, NaI, KI, RbI and CsI at different temperatures have been evaluated making use of the data of elastic constants of the single crystals and employing Kudriavtsev's theory. In all these alkali halides, the lattice energies are found to decrease with increase in temperature. At any given temperature, the lattice energy of LiCl <62> NaCl <62> KCl <62> RbCl, LiBr <62> NaBr <62> KBr <62> RbBr <62> CsBr, NaI <62> KI <62> RbI <62> CsI and RbF <62> RbCl <62> RbBr <62> RbI indicating that as the size of the alkali metal ion or halide ion increases, the lattice energy of the alkali halide crystal decreases. The results are discussed in the light of mutual interaction of the ions and increase in amplitude of lattice vibrations with temperatures.

3 illus, 24 ref

014298   Subrahmanyam M;Rajagopal E;Murthy N M (Dep of Phys, Sri Kriashnadevaraya Univ, Anantapur-515 003) : Temperature dependence of lattice energy of fluorite type AB₂ crystals, alkaline earth oxides and heavy metal halides-Evaluation from sound velocity data. Indian J pure appl Phys 2005, 43(9), 660-3.

Lattice energies of CaF₂, SrF₂, BaF₂, CdF₂, EuF₂, MgO, SrCl, AgCl and TlBr at different temperatures have been evaluated making use of single crystal elastic constant data and employing Kudriavtsev's theory which relates the lattice energy of the crystal, U, with mean sound velocity, u_me crystal. The lattice energies of both MgO and SrO decrease with increase in temperature and the variations are parabolic and similar. The lattice energies of AgCl and TIBr vary with temperature parabolically up to 80 K and thereafter linearly up to 300 K. The results are explained in terms of the structure of the crystals, mutual interaction of the ions and anharmonic effects associated with as a function of temperature.

3 illus, 32 ref

014297   Siva Prasad V;Sivakumar K V;Raja Gopal E; Manohara Murthy N (Dep of Phys, Sri Krishnadevaraya Univ, Anantapur-515 003) : Ultrasonic behaviour of ternary mixtures containing water, dimethylsulphoxide and t-Butanol at 298.15 K. J pure appl Ultrasonics 2005, 27(1), 8-14.

Ultrasonic velocities in and adiabatic compressibilities of aqueous solutions of Water + dimethylsulphoxide (DMSO) + t-butanol have been determined at 298.15 K. The concentrations of t-butanol at which ultrasonic velocity becomes maximum and adiabatic compressibility becomes minimum are found to decrease with increase in the concentration of DMSO in the cosolvent (Aqueous DMSO). This behaviour indicates that the aqueous ternary solutions are less structured than aqueous t-butanol. This behaviour is also well reflected in the concentration dependence of excess ultrasonic velocity and excess adiabatic compressibility. This behaviour is explained as due to a decrease in the ability of t-butanol to form clathrate hydrates owing to the presence of DMSO. When the concentration of DMSO in the cosolvent (xDMSO) <62> 0.2, ultrasonic velocity decreases and adiabatic compressibility increases with concentration of t-butanol indicating that any further addition of DMSO or t-butanol leads to destabilization of the hydrogen bonded structure of water and t-butanol looses its ability to form clathrate hydrates in aqueous solutions.

4 illus, 1 table, 18 ref

014296   Singh D P;Singh U P (Dep of Phys, FGM Govt Coll, Adampur, Hisar-125 052) : Role of thermal anisotrogy in VLF signal reception on ground. Indian J Phys 2005, 79(10), 1193-6.

Experiment conducted at Siple, Antarctica on Jan 23-24, 1988, VLF signals in the frequency range of 1900-2900 Hz were transmitted to the conjugate point Lake Mitsissini, Canada. Surprisingly, receiving station could not record arrival of signals above 2400 Hz though theoretical cut-off in this case has a value of <126>3.3 kHz corresponding to the line of propagation of 63.7° geomagnetic latitude (L = 5.1) as it is well known that upper cut-off always occurs at f= 0.5 f_H [f is the wave frequency and f_H is the electron gyrofrequency]. Sonwalkar et al analysed these VLF signals and attributed non-reception of such signals to unavailability of sufficient number of energetic electrons. Extending the work of Sonwalkar et al, pitch angle diffusion of electrons along with amplification of interacting VLF signals is studied at L = 5.1. Our analysis provides an explanation of non-reception of f <62> 2.5 kHz signals in terms of scarcity of suitable thermal anisotropy, A(E_r).

3 illus, 3 tables, 15 ref

014295   Singh A K;Singh S B;Singh R P (Dep of Phys, Maharaja Coll, V.K.S. University, Arrah-802 301, Email: abhay_s@rediffmail.com) : Generation mechanism for discrete very low frequency emissions observed at Varanasi. Pramana J Phys 2005, 65(6), 1109-14.

New type of discrete VLF emissions recorded at the low-latitude ground station Varanasi (geomag. lat. 14°55' N, geomag. long. 154°E; L = 1.07) during the strong magnetic activity on 29-30 April 1990 have been reported. A generation mechanism for various temporal and spectral features of discrete VLF emissions recorded at Varanasi is presented on the basis of cyclotron resonance interaction between whistler mode wave and energetic electrons ejected by substorm electric fields. An attempt is also made to determine parallel energy and wave growth relevant to the generation process of discrete VLF emissions. Finally, the results are discussed with other published works.

3 illus, 20 ref

014294   Singh A K;Mehrotra N K (Dep of Phys, Lucknow Univ, Lucknow-226 007, Email: ajaykumar301@rediffmail.com) : Study of NMR spin-lattice relaxation time and mutual viscosity in some substituted anilines. Indian J Phys 2005, 79(10), 1163-67.

Experimental measurements of NMR spin-lattice relaxation time (T₁) of o-anisidine, p-anisidine, o-nitroaniline, o-chloroanilini, m-chloroaniline and p-chloroaniline have been reported. The values of NMR spin-lattice relaxation time (T₁) calculated using Bloembergen, Purcell and Pounds, (BPP) theory are found to be 1/2 to 1/10 times of the experimental values. The author have used various equations of dielectric relaxation time (τ) for calculating T₁, to narrow down this gap. Experimental values of the mutual viscosity (η₁₂) of o-chloroaniline, m-chloroaniline and p-chloroaniline have been also reported. The small difference between the values of η₁₂ and η₁ suggests that the basic model of the dielectric relaxation process does not suffer any major changes even when η₁₂ is used instead of η₁. It has been concluded that the Murty equation gives better representation of the dielectric relaxation phenomenon.

4 tables, 16 ref

014293   Shukla A;Newbert R H H (Dep of Pharm, Inst of Pharmaceutics and Biopharmaceutics, Martin-Luther University Halle-Wittenberg, D-06120 Halle/Saale, Germany) : Investigation of W/O microemulsion droplets by contrast variation light scattering. Pramana J Phys 2005, 65(6), 1097-1108.

Dynamic and static light scattering experiments have been performed at various molar ratios (μ) of water to AOT and temperatures on water-in-oil (W/O) microemulsions dispersed in n-heptane, n-octane, and n-nonane. Size and shape fluctuations of microemulsion droplets are determined with very high precision because polydispersity influences the characteristic features of scattering data as well as the hydrodynamic radius with μ. Self-consistent interpretation of dynamic and static light scattering data using optical properties and packing consideration on the basis of the layered sphere model are obtained. The estimated extent of polydispersity index of 17% is found, whereas the polydispersity is independent of the alkane types. The geometrical parameters, e.g., hydrodynamic radius, area per head group of the surfactant molecule and thickness of the surfactant layer of microemulsion droplets are also estimated and compared in three different n-alkane types. The best interpretation of the temperature dependence of data has shown a transition from spherical droplets to ellipsoid aggregates with increasing temperature. Axial ratio increases with increase of temperature and the longer the alkane the larger is the axial ratio. The parameters describing the polydispersity and shape change are in agreement with theoretical and experimental results found in the literature.

5 illus, 2 tables, 37 ref

014292   Shrivastava K N (Sch of Phys, Univ of Hyderabad, Hyderabad-500 046) : Microwave absorption in Wigner crystals at high magnetic fields. Natn Acad Sci Lett 2005, 28(5-6), 199-203.

A two-dimensional electron gas is formed in between layers of GaAs/AlGaAs. The microwaves of frequency of about <126>-120 MHz are absorbed at a magnetic field of 33 Tesla. From this absorption, the phase diagram of a Wigner crystal was deduced Several different phases are found. Since the phases occur at well defined filling factors, we are able to fix the spin orientation in various phases. At high magnetic fields, the electrons become free and there is no interaction other than the dot product of magnetic moment and the magnetic field.

^ssc2 illus, 2 tables, 15 ref

014291   Shi W Z Y;Zhang D;Wen T (The Ministerial Key Lab on Instrumentation Sci & Dynamic Measmt, Ministry of Educ North China Univ of Sci and Technol, Taiyuan, Shanxi Province, 030051, China, Email: wdzhang@nuc.edu.cn) : A NEMS micro-acoustic sensor based on meso-piezoresistance. J pure appl Ultrasonics 2005, 27(1), 25-8.

In the nano-surface and nano-linear materials based on stress superlattice, generating mechanism and distribution of built-in electric field are various. The inner electric field affects heavily electronic energy state in nano-structure, and the resonant tunnel current is related directly with the electronic energy state. In principle, a mechanical signal can influence the distribution of strains in nanostructure; a built-in electric field can be produced from the variation of the strain distribution in certain conditions; the built-in electric field will results in a variation of quantum states of electrons in nanosystems and the resonant tunnel current depends on the quantum states directly. Based on the above effects, the superlattice nano-membrane can be fabricated to form NEMS acoustic sensor by micro-machining technology. By altering the applying voltage, the sensor can sense the micro-acoustic signals of different frequency bands, and converts them into the strong electrical signal. Briefly, the sensor's working principle and structure characters are introduced.

4 illus, 10 ref

014290   Sarkar S K (Dep of Electron and Telecommun Engng, Jadavpur Univ, Kolkata-700 032, Email: su_sarkar@hotmail.com) : Genetic approach towards the optimization of the system parameters of polar serniconductor quantum wells for better high frequency response. Indian J pure appl Phys 2005, 43(9), 691-6.

The optimized system parameters of polar semiconductor quantum wells have been calculated to get desired high frequency response characterized by 3dB cut-off frequency at which the ac mobility drops to 0.707 of its low frequency value. The ac mobility of two-dimensional hot electrons in square quantum wells of GaAs and (In, Ga)As are computed numerically using heated drifted Fermi-Dirac distribution function and prevalent scattering mechanisms. Genetic algorithm has been employed to get the optimized system parameters for getting the desired high-frequency, small power consuming and low dimensional devices, thereby saving significantly the search time for the technologists involved in the fabrication of such devices.

7 tables, 19 ref

014289   Ranjan K;Dharamvir K;Jindal V K (Dep of Phys, Panjab Univ, Chandigarh-160 014) : Bulk properties of alkali doped C₆₀ solids. Indian J pure appl Phys 2005, 43(9), 654-59.

The model calculations are presented for potassium, rubidium and cesium doped C₆₀ solids formed by exohedral doping in pure C₆₀ solid. The molecular formula is MnC₆₀, M is the alkali metal (K, Rb and Cs) and n takes integer values 1, 3, 4 and 6. The C₆₀ molecule is modelled as a uniform spherical shell having surface density of carbon atoms. Part of the electrons released by ionized alkali atoms distributed on the C₆₀, molecule making it an anion, while the rest (say x) are assumed to form a delocalised electron gas. This electron gas screens the Coulomb interaction between the various anion and cations. With these assumptions, the total cohesive energy is calculated taking into consideration Van der Waals and screened Coulomb interaction between different ions. It was found that the total charge transfer from cation to anion is favoured. Thus ionic character of alkali doped CM solids is established on the basis of the model. The lattice constant, cohesive energy and Bulk modulus for these systems are in good agreement with other calculation or experimental observations. Made make some remarks on phase stability of these solids.

4 illus, 1 table, 22 ref

014288   Ramakrishan T V (NO, , ) : Electrons in condensed matter. Resonance 2005, 10(12), 23-38.

6 illus

014287   Rai V N;Yueh F Y;Singh P (Laser Plasma Div, Cent for Advd Technol, Indore-452 013) : Optical emission from laser-produced chromium and magnesium plasma under the effect of two sequential laser pulses. Pramana J Phys 2005, 65(6), 1075-83.

Parametric study of optical emission from two successive laser pulses produced chromium and magnesium plasma is presented. The line emission from chromium and magnesium plasma showed an increase by more than six times for double laser pulse excitation than for single-pulse excitation. An optimum increase in emission intensity was noted for inter-pulse delay of <126> 2-3 μs for all the elements. The experimental observations were qualitatively explained on the basis of absorption of second laser pulse in the pre-formed (by first laser) coronal plasma by inverse Bremsstrahlung process, which were found responsible for the excitation of more ions and atoms in the plasma. This process starts as the plasma scale length becomes greater than the laser wavelength. This study further indicate the suitability of this technique in the field of elemental analysis.

3 illus, 1 table, 20 ref

014286   Qureshi M S;Dubey R N;Tyagi A (NO, Maulana Azad Natn Inst of Technol, Bhopal-462 007) : Effects of forming magnetic field on characteristics of photo-magneto-electrets of kapton-H polyimide. Indian J pure appl Phys 2005, 43(9), 684-7.

Photo-magneto-electrets of kapton-H-polyimide, a photoconducting material, have been prepared under various magnetic fields. Formation current, dark depolarization and photo-depolarization current studies have been reported Formation current increases and becomes constant after some time. Saturation current increases with forming magnetic field. The variations of depolarization current of PMEs of kapton-H-polyimide, show a sharp maximum and then current decays, becoming constant in about ten min. Total area below the depolarization current versus time gives an idea about the volume polarization in the dielectric by simultaneous application of magnetic field and optical radiation.

7 illus, 10 ref

014285   PremNazeer K;Thamilselvan M;Mangalaraj J; Narayandass S K (Thin Film Lab Dep of Phys, Bharathiar Univ, Coimbatore-641 046, Email: dmraj800@yahoo.com) : Field and temperature dependent transport properties of undoped and doped polyaniline films. J Polym Mater 2005, 22(3), 321-31.

Low and high electric field conductivity measurements were carried out in undoped and (±)- 10-camphor sulfonic acid (CSA) dopedpolyaniline (PANI) film samples in the temperature range 173 ≤ T ≤ 303 K and 303 ≤ T ≤ 383 K, respectively. In the undoped and doped polyaniline films one and three dimension variable range hopping (VRH) type is identified, respectively, at low electric field (1 x 10³ V/cm) in the temperature range 173 ≤ T ≤ 303 K. The VRH parameters such as localization length (α^-1), hopping range (R_hop) and hopping energy (W) are calculated and the influence of doping on these parameters is discussed. The current - voltage (I - V) characteristics studied at high field (<60>10⁴ V/cm) for the undoped and doped polyaniline films in the temperature range 303 ≤ T ≤ 383 K exhibit the space charge limited current (SCLC) conduction mechanism. The activation energy (E_α) calculated from the plot in θ versus T^-1 of the doped sample is reduced to nearly half of the undoped. The hole mobility (μ) value 7.06 x 10^-8 m² V^-1 s^-1 for UP and 2.37 x 10^-9 m² V¹ s^-1 for DP calculated at 303 Kare well within the limits of reported conjugated polymers. A high value of trap density (N_t = 1.28 x 10²¹ m^-3) is found for doped polyaniline film supports the 1D variable hopping in DP film. The trap parameters such as the trap filled limit voltage (V_TFL), the depth of the dominant trap level (E_t - E_v), the density of states within the hole mobility edge (N_v) are also calculated and their dependence on doping is discussed. The traps exponentially distributed in energy and a single discrete trapping level is found for undoped and doped polyaniline films respectively.

11 illus, 2 tables, 40 ref

014284   Patgiri M;Nimai Singh N (Dep of Phys, Cott Coll, Guwahati-781 001, Email: mahadev@scienist.com) : New uncertainties in QCD-QED rescaling factors using quadrature method. Pramana J Phys 2005, 65(6), 1015-25.

Briefly outlines the quadrature method for estimating uncertainties in a function which depends on several variables, and apply it to estimate the numerical uncertainties in QCD-QED rescaling factors. Employes the one-loop order in QED and three-loop order in QCD evolution equations of the fermion mass renor-malisation. The present calculation is found to be new and also reliable when compared to the earlier values employed by various authors.

7 tables, 13 ref

014283   Pandey R S;Pandey R P;Srivastav A K;Karirm S M;Jha R K (Dep of Phys, Amity Sch of Engng, Sector-125, Noida-201 130, Email: pandeyramashankar@yahoo.com) : Higher harmonics electrostatic ion cyclotron instability with perpendicular AC electric field. Indian J Phys 2005, 79(10), 1179-85.

Electrostatic ion - cyclotron long wave length instability has been studied for higher harmonics with perpendicular AC electric field. Harmonics - dependent current - driven oblique propagating electrostatic ion - cyclotron instability (EICI) has been studied with density gradient in the region of ionosphere.

7 illus, 16 ref

014282   Nityanand R (NO, , ) : Schrodinger's uncertainty principle?. Resonance 2005, 10(12), 52-5.

2 ref

014281   Nayak B K;Mirgule E T;Chaoudhary R K (Nuclear Phys Div, Bhabha Atom Res Cent, Mumbai-400 085) : Application of pulse shape discrimination in Si detector for fission fragment angular distribution measurements. Pramana J Phys 2005, 65(6), 1053-9.

Pulse shape discrimination (PSD) with totally depleted transmission type Si surface barrier detector in reverse mount has been investigated to identify fission fragments in the presence of elastic background in heavy ion-induced fission reactions by both numerical simulation and experimental studies. The PSD method is compared with the other conventional methods adopted to identify fission fragments with solid-state detectors such as ΔE-E telescope and single thin ΔE detector and the data for the ¹⁰B + ²³²Th fission reaction are presented. Results demonstrate the usefulness of a single transmission-type surface barrier detector for the identification of fission fragments and projectiles like heavy ions.

5 illus, 10 ref

014280   Nagesh E D V;Santosh Babu G;Subramanian V (Dep of Phys, Indian Inst of Technol, Chennai-600 036, Email: manianvs@iitm.ac.in) : Two-dimensional microwave band-gap structures of different dielectric materials. Pramana J Phys 2005, 65(6), 1115-20.

Reports the use of low dielectric constant materials to form two-dimensional microwave band-gap structures for achieving high gap-to-midgap ratio. The variable parameters chosen are the lattice spacing and the geometric structure. The selected geometries axe square and triangular and the materials chosen are PTFE (ε = 2.1), PVC (ε- 2.38) and glass (ε = 5.5). Using the plane-wave expansion method, proper lattice spacing is selected for each structure and material. The observed experimental results are analyzed with the help of the theoretical prediction.

3 illus, 2 tables, 13 ref

014279   Mehta P;Mishra V;Kataria S K (Electron Div, Bhabha Atom Res Cent, Mumbai-400 085) : Silicon drift detectors with integrated JFET Simulation and design. Indian J pure appl Phys 2005, 43(9), 705-13.

High resolution, low energy X-ray spectroscopy systems have been developed recently using the Silicon drift detector (SDD) with in-built Junction field effect transistor (JFET). A comprehensive simulation study of the SDD and Integrated JFET with a view to formulate the design flow has been carried out. An optimized process flow for fabrication of SDD and integrated JFET on high resistivity detector substrate is presented. Based on these studies, several mask layouts for the SE JFET and reset MOSFET have been designed.

10 illus, 1 table, 15 ref

014278   Kushwaha A K;Kushwaha S S (Dep of Phys Inst of Basic Sci, Bundelkhand Univ, Jhansi-284 121, Email: akkphys_bu@yahoo.com) : Effective charges in ternary chalcogenide spinels. Indian J pure appl Phys 2005, 43(9), 664-7.

The effective ionic charge Z*e of each ion is determined within a narrow variable range for ternary chalcogenide spinel compounds. The Szigeti effective charge e*s is also evaluated for the anion and cation using the observed optical dielectric constant ε_∞. The correlation between e*_s and the dielectric constant ε_∞ are empirically found as ε_∞-1=2.0/[e*_s./Z_effe )+(e*_s./Z_effe)²]. From effective ionic charges, It was concluded that the ionicity increases in the order oxide <62> sulphide <62> selenide, indium compounds <62> chromium compounds, normal spinel <62> inverse spinel.

1 illus, 3 tables, 26 ref

014277   Kulkarni B D;Mandal B N;Mulye S S;Deshpande N R (NO, Indian Inst of Trop Meteorology, Pune-8) : Estimation of design storm for the Manjra catchment. J appl Hydrol 2004, 17(2-3), 52-9.

Hydrometeorological study for the Manjra river catchment upto its confluence with the river Godavari having an area 30,844 sq. km has been made using all available long period rainfall data upto 1990 for stations in and around the basin. Estimation of Probable Maximum Precipitation (PMP) by physical method for the Manjra catchment upto its Confluence with the river Godavari has been attempted.

3 illus, 5 tables, 8 ref

014276   Khatua S C;Maiti S (NO, KE Tech Texts Pvt. Ltd., Rupnarayanpur, Kharagpur-721 301, Email: sukumarmaiti@indiatimes.com ) : Preparation of polyimide films by the single-step process. J Polym Mater 2005, 22(3), 341-6.

Soluble high molecular weight polyimide (PI) was synthesized by the single-step polycbndensation reaction of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) with 4,4'-oxydianiline (ODA) in a phenolic solvent like p-chlorophenol. Even replacement of diamine, ODA, by 10% with a proprietary rigid diamine, PD, gave rise to a high molecular weight soluble polyimide in p-chlorophenol. Films were developed from these solutions of polyimides. Mechanical properties, thermal stability, chemical/solvent resistance etc. of one of the resulting PI films were tested.

4 tables, 19 ref

014275   Karmakar D (TPPED, Bhabha Atom Res Cent, Trombay, Mumbai-400 083, Email: debjan@magnum.barc.ernet.in) : Studies of magnetization and related properties for hard type-II superconductors. Indian J Phys 2005, 79(10), 1107-47.

Magnetization and the related properties of type-II superconductor are studied in the framework of Critical State Model. Author categorized the solvable sample geometries into three possible solvable classes and addressed some unsolved non-trivial problems in each of these three classes. Applications of these problems for realistic experimental situations are discussed. The theoretical results obtained have a good resemblance with the experimental results. A brief discussion of the earlier literature is also presented.

39 illus, 66 ref

014274   Kande A;Adebayo G A;Akinlade O (NO, The Abdus Salam Int Cent for Theoretical Phys, Trieste, Italy) : Structural properties of low-density liquid alkali metals. Pramana J Phys 2005, 65(6), 1085-96.

The static structure factors of liquid alkali metals have been modelled at temperatures close to their melting points and a few higher temperatures using the reverse Monte Carlo (RMC) method. The positions of 5000 atoms in a box, with full periodicity, were altered until the experimental diffraction data of the structure factor agrees with the associated model structure factor within the errors. The model generated is then analysed. The position of the first peak of the pair distribution function g(τ) does not show any significant temperature dependence and the mean bond lengths can be approximated within an interval of 3.6-5.3 <65>, 4.5-6.6 <65> 4.8-6.7 <65> and 5.1-7.3 <65> for Na, K, Rb and Cs respectively. The cosine bond distributions show similar trend with the flattening up of the first peak with increase in temperature. In addition, the coordination numbers of these liquid metals are high due to the presence of non-covalent bonding between them. On the average, surmises that the coordination number decreases with increase in temperature.

6 illus, 3 tables, 15 ref

014273   Kailash K;Kushwaha K S;Shrivastava S K;Raju K M (Dep of Phys, Brahmanand P.G. Coll, Rath, Hamirpur-210 431) : Internal structure, inherent and anharmonic properties of some mono- and di-valent materials. J pure appl Ultrasonics 2005, 27(1), 29-36.

If the values of second order elastic constants and density at a particular temperature are known for any substance, one may obtain ultrasonic velocities for longitudinal and shear waves which give an important information about its internal structure, inherent and anharmonic properties. An effort has been made for obtaining the internal structure, inherent and anharmonic properties of some mono- and divalent face centered cubic crystals starting from nearest neighbour distance and hardness parameter assuming long- and short-range potentials at an elevated temperature. The elastic energy density for a deformed crystal can be expanded as power series of strains for obtaining coefficients of quadratic, cubic and quartic terms which are known as the second, third and fourth order elastic constants respectively. When the values of the higher order elastic constants are known for a crystal, many of the anharmonic properties of the crystal can be treated within the limit of the continuum approximation in a quantitative manner. The higher order elastic constants are computed at 300K for Alkali Cyanides, Sodium and Potassium Halides and fourteen divalent crystals. The first order pressure derivatives of second and third order elastic constants, the second order pressure derivatives of second order elastic constants and partial contractions are evaluated at room temperature for these substances.

7 tables, 28 ref

014272   Jakhar U R;Yadav H L;Ansari A (Dep of Phys, Raj Univ, Jaipur-302 004) : Structure of high spin states of <. Pramana J Phys 2005, 65(6), 1041-51.

Following a fully self-consistent cranked Hartree-Fock-Bogoliubov (CHFB) approach with a pairing + quadrupole + hexadecapole model interaction Hamiltonian the structure of the yrast states of ^76,78Kr nuclei is studied up to angular momentum J = 24. Evolution of the shape with spin, and rotation alignment of proton as well as neutron Og_9/2 orbitals is investigated along with the inter- and intra-nucleus variations of the g factors as a function of J. Finds that the shape of ⁷⁸Kr remains prolate all through up to J = 24, whereas ⁷⁶Kr becomes triaxial beyond J=12.

6 illus, 3 tables, 20 ref

014271   Jai Prakash (Dep of Phys, D.D.U. Gorakhpur Univ, Gorakhpur-273 009) : Experiment for studying vacancy migration in alkali halides. Natn Acad Sci Lett 2005, 28(1-2), 35-8.

An experiment has been proposed to study the mechanism of vacancy migration in divalent doped alkali halide crystals. Polarized impurity- vacancy dipoles are obtained through rapid cooling of the sample in the presence of static electric field. Switching off the electric field at such a low temperature keeps the polarized dipoles in the frozen-in condition. Now, an alternating electric field is applied in a direction perpendicular to the direction of static electric field. The frequency of the alternating electric field is varied continuously and the required condition of maximum loss is detected experimentally. Proposed experiment has the potentiality to be used as a very sensitive and accurate tool for such studies.

^ssc3 illus, 2 tables, 2 ref

014270   Gupta R D;Joshi S K;Shrivastava B D;Shah M C; Prasad J (Phys Dep, Govt Post Grad Coll, Mandsaur-458 001) : Estimation of X-ray absorption fine structure phase shifts of copper (II) complexes. Natn Acad Sci Lett 2005, 28(1-2), 39-44.

X-ray K-absorption EXAFS (extended X-ray absorption fine structure) data for five copper(II) mixed ligand complexes with triphenyl phosphine as a common ligand have been analysed for the estimation of phase parameters α₁, β₁ and δ₁. The studies reveal that the contribution of backscattering phase shift the total phase shift varies with the change in ligands surrounding the central metal ion copper. The total phase shift values for the complexes indicate a linear variation with wave vector k. Modified graphical method of Lytle, Stern and Sayers has been used to obtain the average bond lengths of the complexes.

^ssc2 illus, 3 tables, 25 ref

014269   Gopinathan T C;Menon C S (Phys Dep, KEC Coll, Mannanam, Kottayam-686 561, Email: tggopinath@sancharnet.in) : Effect of substrate temperature and annealing on the electrical and optical properties of zinc phthalocyanine thin films. Asian J Chem 2005, 17(3), 1963-70.

Zinc phthalocyanine thin films are prepared at different substrate temperatures at a base pressure of 10 m bar. Thin films are coated on glass substrates by thermal evaporation technique. Samples of equal thickness coated at room temperature are subjected to post-deposition annealing at different temperatures in air and vacuum for 1 h. The electrical conductivity studies are carried out by keeping the samples in a conductivity cell at a pressure of 10^-3 mbar in the temperature range of 300-500 K. The electrical conductivity is plotted as a function of absolute temperature. The conduction mechanism is observed to be hopping. The thermal activation energy was calculated and observed to vary with annealing temperature and substrate temperature. The optical absorption studies were done in the UV-Visible region. The optical band gap energies of the samples were calculated.

7 illus, 5 tables, 15 ref

014268   Goel P;Sharma S;Yadav K L;James A R (Smart Mater Res Lab Dep of Phys, Indian Inst of Technol, Roorkee-247 667, Email: klyadav35@yahoo.com) : Structural and dielectric properties of phosphorous-doped PLZT ceramics. Pramana J Phys 2005, 65(6), 1127-32.

Reports the unique effects of P₂O₅-doped PLZT ceramics with composition (Pb_0.92 La_0.08) (Zr_0.65 Ti_0.35)O₃ + x wt% of P₂O₅ (where x = 1, 3 and 5) prepared chemically by co-precipitation method. X-ray diffraction studies suggest that the prepared compound was very fine (10-25 nm), homogeneous and of rhombohedral symmetry. The apparent density of samples decreased with the P⁵⁺ additions. Studies of dielectric constant and dielectric loss as a function of frequency (10-1000 kHz) and temperature suggest that the compound undergoes diffuse type of phase transition without any sign of relaxor behaviour. With increasing x, dielectric constant was found to decrease appreciably, whereas Curie temperature (T_C) was found to increase.

3 illus, 1 table, 22 ref

014267   Ghanshyam;Burnwal A P;Rai P (Dep of Phys, BIT, Sindri, Dnanbad-828 123, Email: ghanshyam123@rediffmail.com) : Filamentation instability of an electromagnetic waves in an expanding homogeneous plasmas. Indian J Phys 2005, 79(10), 1211-14.

A high intensity laser beam propagating at an angle to the flow velocity v_b of a moving plasma is susceptible to filamentation instability. The nonlinearity arises through the ponderomotive force and the growth rate is sensitive to the angle between k and V_b, and the ratio of the expansion velocity to the sound speed. The motion of the plasma introduces finite real frequency to the low frequency ion-quasimode.

2 illus, 16 ref

014266   George C;Kolappadan C;Soman E G (Cent for Wat Resour Dev and Mgmt, Sub Cent, Manimalakunnu, Koothattukulam, Ernakulam-686 679) : Drought estimation through rainfall analysis for Odakkali region in Kerala state. J appl Hydrol 2004, 17(2-3), 47-51.

Rainfall is the major determinant of agricultural production, especially in rainfed areas. Since the contribution of rainfed agriculture is almost half to the national kitty and about 68 per cent of the sown area is still dependent on rainfall it is imperative that the prediction of rainfall pattern should be accurate and reliable. So, it would be prudent to go for localized predictions. In view of this, an attempt has been made to estimate occurrence of drought at Odakkali through rainfall analysis of twenty five years (1967 - 1991). Analysis shows that mean annual rainfall of Odakkali is 3255.7 mm with 14 per cent variations. Study also reveals that 8 per cent of the years were drought, 68 per cent normal and 24 per cent were surplus years, implying that there is a likelihood of one drought year in a 12 year span. Probability analysis of drought months indicates that in any year, there are strong chances of occurrence of three drought months with 70 per cent probability. It was found that July was wettest month (733.8 mm rainfall) followed by June (667.6 mm).

3 illus, 3 tables, 2 ref

014265   Dorai K (NO, , ) : Magnetic resonance imaging. Resonance 2005, 10(12), 203-16.

4 illus,

014264   Dogan A;Havvatoglu Y (KSU, Fen-Edebiyat Fakultesi, Fizik Bolumu, Avsar Kampusu, 46100, K.Maras, Turkey) : Crystallographic analysis of fcc → bcc martensitic phase transformation observed in Fe-31 wt % Ni alloy using infinitesimal deformation approach. Indian J pure appl Phys 2005, 43(9), 668-74.

The solutions for crystallographical parameters such as habit plane orientation, rotation matrix, total shape deformation matrix, orientation relationship between austenite and martensite crystal axis, etc. have been obtained by using infinitesimal deformation approach, taking into account the basic concepts of Finite deformation phenomenological crystallographic theories associated with martensitic transformations. Numerical values obtained have been compared with the predictions of the crystallographic theories and experimental results.

1 illus, 4 tables, 18 ref

014263   Das M K;Patgiri M;Nimai Singh N (Dep of Phys, Gauhati Univ, Guwahati-781 014, Email: mahadev@scientist.com) : Numerical consistency check between two approaches to radiative corrections for neutrino masses and mixings. Pramana J Phys 2005, 65(6), 995-1013.

Briefly outlines the two popular approaches on radiative corrections to neutrino masses and mixing angles, and then carry out a detailed numerical analysis for a consistency check between them in MSSM. Finds that the two approaches are nearly consistent with a discrepancy factor of 4.2% with running vacuum expectation value (VEV) (13% for scale-independent VEV) in mass eigenvalues at low-energy scale but the predictions on mixing angles are almost consistent. Checks the stability of the three types of neutrino models, i.e., hierarchical, inverted hierarchical and degenerate models, under radiative corrections, using both approaches, and find consistent conclusions. The neutrino mass models which are found to be stable under radiative corrections in MSSM are the normal hierarchical model and the inverted hierarchical model with opposite CP parity. Carries out numerical analysis on some important conjectures related to radiative corrections in the MSSM, viz., radiative magnification of solar and atmospheric mixings in the case of nearly degenerate model having same CP parity (MPR conjecture) and radiative generation of solar mass scale in exactly two-fold degenerate model with opposite CP parity and non-zero U_e3 (JM conjecture). Observes certain exceptions to these conjectures. Finds a new result that both solar mass scale and U_e3 can be generated through radiative corrections at low energy scale. Finally the effect of scale-dependent vacuum expectation value in neutrino mass renormalisation is discussed.

5 illus, 5 tables, 26 ref

014262   Das M B;Karmakar S (NO, Saha Inst of Nuclear Phys, 1/AF, Bidhannagar, Kolkata-700 064) : Lifetime measurement of excited atomic and ionic states of some noble gases using the high-frequency deflection technique. Pramana J Phys 2005, 65(6), 1061-74.

High-frequency deflection (HFD) technique with a delayed coincidence single photon counting arrangement is an efficient technique for radiative lifetime measurement. An apparatus for measurement of the radiative lifetime of atoms and molecules has been developed in the laboratory and measurements have been performed with great success in a large number of atoms and ions. The present version of the apparatus is described together with a brief description of the basic features and performance.

7 illus, 26 ref

014261   Chopra I S;Jindal V K (Dep of Phys, Panjab Univ, Chandigarh-160 014, Email: jindal@pu.ac.in) : Production of C₆₀ by the arc ignition of graphite. Panjab Univ Res J Sci 2004, 54, 65-7.

Reports production of C₆₀ using the arc ignition of graphite. A set up was developed at Department of Physics, which uses an evacuated chamber having a free flow of He gas at desired pressures. This also had a provision to bring two graphite rods through which large D. C current can be passed using a high current low voltage power supply. Provision for cooling the graphite rods by circulating cold water around, considering that the temperatures could rise up to 4000°C. The resultant carbon soot was purified and characterized by FTIR. The observed IR peeks confirmed the presence of Solid C₆₀. Thus we have at our disposal a set up for the production of C₆₀ n of solid C₆₀.

2 illus, 1 table, 7 ref

014260   Chaudhuri S (Dep of Phys, Gushkara Mahavidayala, Gushkara, Burdwan-713 128, Email: sarbes@rediffmail.com) : Stationary axisymmetric one-soliton solutions of Einstein field equations. Indian J Phys 2005, 79(10), 1187-91.

Author has constructed one-soliton solutions of Einstein's equations for an axisymmetric stationary line element. The generated solutions are not, in general, asymptotically flat. However, at the equator the solutions are found to be spatially well-behaved at infinity. When some restrictions are imposed on the constants, the solutions reduce to the solutions of Verdaguer, Letelier, Van Stockum and Weyl.

9 ref

014259   Chaudhari G N;Padole P R;Bodade A B;Patil S S (Gas-Sensor and Thin Films Lab Dep of Chem, Shri Shivaji Sci Coll, Amravati-444 602, Email: gnc4@indiatimes.com) : Sensitivity and selectivity of chemically modified nanosized SnO₂ based CO sensors. Indian J Phys 2005, 79(10), 1157-62.

Among the various metal oxide additives, Bi₂O₃ is outstanding in promoting the sensing properties of SnO₂ element to CO gas in dry air. The structural characterizations of chemically modified nano-sized SnO₂ were performed by using XRD with different calcination temperatures. XRD pattern for 10 wt. % Bi_{2D<>O3 doped SnO2 calcined at 600°C, indicates complete phase formation and crystallite size was found to be 65 nm. The sensor has been characterized by d.c. electrical measurements for different gases such as CO, LPG, H2S, and H2 in dry air. The element of 10 wt. % Bi2O3 doped SnO2 shows maximum sensitivity and selectivity for CO sensor at an operating temperature 225°C. Further improvement in the sensitivity was achieved by adding 1 wt. % Pd in 10 wt. % Bi2O3: SnO2 at an operating temperature 200°C for CO sensors. Sensitivity for 10 wt. % Bi2O3 doped SnO2 with gas concentrations shows to increase linearly with gas concentration up to 600 ppm. It is observed that the gas has tendency to saturate at gas concentrations above 600 ppm.}

9 illus, 20 ref

014258   Chaturvedi S;Ercolessi E;Marmo G;Morandi G; Mukunda N;Simon R (NO, Sch of Phys Univ of Hyderabad, Hyderabad-500 046) : Wigner distributions for finite dimensional quantum systems: an algebraic approach. Pramana J Phys 2005, 65(6), 981-93.

Discusses questions pertaining to the definition of 'momentum', 'momentum space', 'phase space' and 'Wigner distributions'; for finite dimensional quantum systems. For such systems, where traditional concepts of 'momenta' established for continuum situations offer little help, proposes a physically reasonable and mathematically tangible definition and use it for the purpose of setting up Wigner distributions in a purely algebraic manner. It is found that the point of view adopted here is limited to odd dimensional systems only. The mathematical reasons which force this situation are examined in detail.

14 ref

014257   Chattopadhyay R;Ganda S C (NO, Haripal G D Inst, Khamarchandi, Hooghly-712 405, Email: rchattopadhyay2001@yahoo.com) : Covariation of f₀F₂ and three solar indices. Indian J Phys 2005, 79(10), 1197-1201.

Covariation of critical frequency (f₀F₂) of F₂-layer of the terrestrial ionosphere with three important solar parameters, namely relative sunspot number, 2800 MHz solar flux and solar flare number has been investigated and the following results have been obtained; (i) Strong correlation exists between the critical frequency and each of the three solar parameters, (ii) Critical frequency of F₂-layer increases nonlinearly with solar parameters reaching a maximum at sunspot maximum, (iii) Empirical equations connecting critical frequency of f₂ layer with solar parameters have been derived by applying least-square method of curve-fitting which gives values of critical frequency of f₂ layer very close to the experimentally obtained values of the same.

2 illus, 5 tables, 16 ref

014256   Chandrasekhara M S;Sannappa J;Pramesh L (Dep of Stud in Phys, Univ of Mysore, Manasagangotri, Mysore-570 006) : Electrical conductivity of air related to ion pair production rate from radon and its progeny concentrations in dwellings of Mysore city. Indian J pure appl Phys 2005, 43(9), 679-83.

Radon gases released from the ground surface and building materials are the major sources of ionization in the indoor atmosphere. Radon will undergo radioactive decay in the atmosphere by emitting an alpha particle. The alpha and beta particles, and the gama rays from ²²²Rn, ²²⁰Rn and their decay products give up their energy by ionizing the molecules and aerosol particles in the atmosphere. Radon and its progeny concentrations and the electrical conductivity of air due to both polarities were measured simultaneously at a height of 1 m from the floor inside dwellings of Mysore city, India. Diurnal variations of radon and its progeny concentrations show their peak values in the early morning (0200 to 0600 hrs) throughout the year. Observations show an increase in the concentration of radon and its progeny during night time compared to the daytime values. The electrical conductivity of the atmospheric air also exhibits similar trend. These results are discussed in terms of ionization rate due to radioactivity and the influence of meteorological parameters on radon and its progeny concentrations.

4 illus, 14 ref

014255   Chandra S (Sch of Phys Sci, S.R.T.M. Univ, Nanded-431 606) : Relation between spectroscopic constants with limited Dunham coefficients. Pramana J Phys 2005, 65(6), 1133-7.

Statement of Kaur and Mahajan [1] about the definition of Δ used by Chandra [2] is not correct. Even if we take Δ = μω²_e τ²_e/2D_e, the relation between Δ and G(=8ω_ex_e/B_e) is obtained as Δ= 4.21452856G, provided the vibrational energy of a diatomic molecule is expressed in terms of limited Dunham coefficients, Y₁₀, Y₂₀, Y₀₁ and Y₁₁. This relation is still different from that of Kaur and Mahajan [3].

1 illus, 1 table, 9 ref

014254   Bandyopadhyay B;Kundu A;Datta A N (Dep of Radiophysics & Electron, Univ Coll of Sci and Technol, University of Calcutta, Kolkata-700 009) : Iterative algorithm for microwave tomography using Levenberg-Marquardt regularization technique. Indian J pure appl Phys 2005, 43(9), 649-53.

An inverse iterative algorithm for microwave imaging based on moment method solution is presented here. The iterative scheme has been developed on constrained optimization technique and is certain to converge. The algorithm is applied to synthetic data and the results of reconstruction of complex permittivity distribution show a very high degree of accuracy. Levenberg - Marquardt method solves the ill posedness of the problem.

4 illus, 15 ref

014253   Bakkialakshmi S;Shanthi B;Santhi R; Chandrakala D (Dep of Phys, Annamalai Univ, Annamalai Nagar-608 002) : Influence of nitrobenzene and acetonitrile in p-chloroaniline and 1, 4-dioxane. Asian J Chem 2005, 17(3), 1705-8.

Attemept has been made to obtain the fluorescence quenching spectra of p-chloroaniline using nitrobenzene and acetonitrile, as quenchers in 1, 4-dioxane. The concentration of fluorescer solution was kept constant (0.01 m) in each experiment, by adding fixed aliquot of stock solutions prepared in the solvent. Quenchers (nitrobenzene and acetonitrile) in the respective solvent was added to the above solution in small volumes (0.1-0.5 mL) and the fluorescent intensities were measured. The Stern-Volmer constants for all quenching processes were plotted. Regression analysis for Stern-Volmer plot was carried out. Regression coefficient and the Stern-Volmer constant were calculated. Stoke's shift, ionization potential, electron affinity and the solvent parameter were also calculated.

3 illus, 2 tables, 8 ref

014252   Arumugam V;Naresh M D;Balakrishnan R;Sanjeevi R;Pradeepa K;Jayakumar K (Biophys Dep, Central Leather Research Institute, Adyar, Chennai-600 020) : Ultrasonic studies on the blends of styrene butadiene rubber with PMMA and PVAC. J pure appl Ultrasonics 2005, 27(1), 1-7.

Miscibility of Styrene butadiene rubber (SBR) with poly Methyl methacrylate (PMMA) and poly Vinyl acetate (PVAC) blends in tetra hydrofuran (THF) were studied using ultrasonic technique. The interaction parameters computed based on the viscosity data were also analyzed. The ultrasonic study indicates that the SBR : PMMA blend is miscible. In the case of SBR:PVAC blend both the ultrasonic and viscometric studies indicate immiscibility. Various ultrasonic parameters have been calculated and they also show the same trend. The study clearly shows that the ultrasonic technique is an easy method to estimate the miscibility of polymer blend solutions. The ultrasonic results were also confirmed by optical studies.

13 illus, 2 tables, 12 ref

014251   Ali S;Alimuddin;Reddy R (Dep of Appl Phys, Z.H. Coll of Engng & Technol, Aligarh Muslim University, Aligarh-202 002) : Mossbauer study of some biological iron complexes. Pramana J Phys 2005, 65(6), 1121-6.

Some biological complexes containing iron are investigated experimentally at room temperature using the Mossbauer resonance. The complexes show quadrupole doublet and Kramer's degeneracy is found to exist. The electric field gradient, difference in s-electron densities and quadrupole coupling constant have been calculated in each case. These parameters are used to obtain information on the surroundings of the Mossbauer atom.

5 illus, 1 table, 12 ref