013219   Deshmukh S H;Burghate K D;Deogaonkar V S (P G Dep STOPWORD Phys, Shri Shivaji Sci Coll, Amravati-444 603, Email: ati_Shivaji@sancharnet.in) : Electrical conduction in semiconducting PVC-PMMA thin film. Indian J Phys 2005, 79(11), 1263-7.

The electrical conduction in mixed polymer films, polyvinylchloride (PVC) and polymethylmethacrylate (PMMA) have been studied by finding the I-V characteristics at various temperatures in the range of 323K-363K. The results are presented in the form of I-V characteristics and analysis has been made in the light of Poole-Frenkel, Fowler-Nordheim, Schottky, log (J) versus T plots, Richardson and Arrehenius plots. It has been observed that the Schottky and Richardson mechanisms are mainly responsible for the conduction mechanism in the case of sample film PVC-PMMA.

7 illus, 23 ref

013218   Chattopadhyay T K (NO, The Fundamentals, BC 160, Salt Lake City, Kolkata-700 064, Email: webtech_edu@vsnl.com) : A new look at buoyancy calculations for solids of definite geometric shapes. Phys Educ 2004, 21(3-4), 171-4.

Buoyancy (net upthrust) on two solid bodies, one a cone and the other a sphere due to an incompressible liquid has been explicitly calculated basing on elementary calculus and the result obtained in each case is shown to be the usual one mentioned in text books.

2 illus, 5 tables

013217   Chakrabarti S K;Mondar S (NO, S.N. Bose Natn Cent for Basic Sci, JD-Block, Sector-III, Salt Lake, Kolkata-700 098, Email: chakraba@bose.res.in) : A modified gravitational potential to study particles and fluids around a rotating black hole in the equatorial plane. Indian J Phys 2005, 79(11), 1237-41.

Studies of the particle trajectories and the fluid dynamics around a Schwarzschild black hole are regularly carried out using a so-called Paczynski-Wiita potential. A form of the potential, valid on the equatorial plane, which is suitable for the study of the particles around a rotating black hole has been given. It has been shown that the salient features of the orbits, such as the marginally bound orbit and the marginally stable orbit match with those obtained from exact consideration very accurately, provided - 1 ≥ a <147>

2 illus, 7 ref

013216   Bhaumik D (NO, CHEMBIOS Co-op Housing Soc. Ltd., 19, Baishnabghata Patuli Township, Block H, Plot H17, Flat NO. SW21, Kolkata-700 094) : Birth of quantum mechanics. Sci Cult 2005, 71(3-4), 47-51.

Gives overview of the step-by-step development of quantum mechanics.

013215   Bayirli M;Merdan Z (Dep STOPWORD Phys, Gaziosmanpasa Univ, Tokat 60250, Turkey) : The simulation of MnO composed aggregation. Bull pure appl Sci-Sect D 2005, 24(1), 1-7.

Models for diffusion-limited aggregations in which growing clusters from dendritic to compact as well as individual particles are stick probabilities have been investigated in the study. Two versions of the model (A and B) in which the cluster diffusion coefficient is either size independent or inversely proportional to number of particles give very similar results. In the limit of low concentration and large system size both models lead to structures with a topologic (Hausdorff-Besicovitch) dimensionality of 1.657-1.828 in two-dimensional lattice-based simulations.

2 illus, 17 ref

013214   Balaji Rao R;Baskaran G S;Roy D K;Yadagiri Reddy P;Veeraih N (Dep STOPWORD Phys, Acharya Nagarjuna Univ P.G. Cent, Nuzvid-521 201, Email: nvr8@rediffmail.com) : The influence of titanium ions on dielectric, magnetic and optical properties of Li₂O-MO (MgO, CaO, SrO, BaO)-B₂O₃ glass system. Indian J Phys 2005, 79(11), 1253-62.

Dielectric properties viz. dielectric constant (ε'), loss (tan δ ), a.c. conductivity (σ), in the frequency range of 10²-10⁶ Hz and in the temperature range of 30-300°C and the dielectric breakdown strength in air of Li₂O-MO-B₂O₃(MO = MgO, CaO, SrO, BaO) glasses containing different concentrations of TiO₂ (in the range of 0-1.0 mol%) have been investigated. Results have been analyzed in the light of different oxidation states of titanium ions in the glass matrix with the aid of data on spectroscopic properties (optical absorption, ESR and IR spectra), magnetic properties (magnetic susceptibility) and thermoluminescence studies.

3 illus, 11 tables, 47 ref

013213   Bakkialakshmi S;Shanthi B;Santhi R; Chandrakala D (Dep STOPWORD Phys, Annamalai Univ, Annamalai Nagar-608 002) : Evaluation of aniline with nitrobenzene and acetonitrile under controlled condition. Bull pure appl Sci-Sect D 2005, 24(1), 19-22.

Fluorescence of aniline at room temperature is polluted by the addition of nitrobenzene and aectonitrile. The Stern-Volmer constant and the regression coefficient are reported. Ionization potential, electron affinity and the solvent parameter are calculated. The reduction by molecules containing only electron donating substitutents involves a charge transfer complex.

2 illus, 2 tables, 7 ref

013212   Bakkialakshmi S;Shanthi B;Priyadharsini A (Dep STOPWORD Phys, Annamalai Univ, Annmalai Nagar-608 002) : Quenching of p-anisidine and p-chloroaniline by picric acid in methanol. Bull pure appl Sci-Sect D 2005, 24(1), 61-4.

Attempt has been made to obtain the fluorescence quenching spectra of p-anisidine and p-chloroaniline using picric acid as a quencher in methanol. The concentration of fluorescer solution was kept constant (0.01M) in each experiment, by adding fixed aliquot of stock solutions prepared in the solvent. Quencher (picric acid) in the respective solvent was added to the above solution in small volumes (0.1 ml to 0.5 ml) and the fluorescent intensities were measured. The stern-volmer constants for all the quenching processes have been plotted. Regression analysis for stern-volmer plot has been carried out. Regression coefficient (r) and the stern-volmer constant (Ksv) were calculated. Stoke's shift, ionization potential, electron affinity and the solvent parameter (z) have also been clacualted.

3 illus, 1 table, 5 ref

013211   Bakkialakshmi S;Shanthi B;Chandrakala D; Santhi R (Dep STOPWORD Phys, Annamalai Univ, Annamalai nagar-608 002) : Fluorescence quenching of diphenylamine. Bull pure appl Sci-Sect D 2004, 23(2), 93-5.

Quenching of fluorescence of diphenylamine by benzoic acid and carbon tetrachloride have been studied in benzene solvent at room temperature to understand the quenching mechanism. The stern-volmer plot have been found to be linear for both the quenchers. Regression coefficient (r), the stern-volmer constant (K_sv), stoke's shift, ionization potential, electron affinity and the solvent parameter have also been calculated. The results suggest that the quenching here is not static but dynamic in nature. Diphenylamine should be contaminated by benzoic acid and carbon tetrachloride in benzene.

^iia2 illus, 2 tables

013210   Bahadur D;Giri J;Nayak B B;Sriharsha T; Pradhan P;Prasad N K;Barick K C;Ambashta R D (Dep STOPWORD Metall Engng STOPWORD Mater Sci, Inst of Technology-Bombay, Mumbai-400 076, Email: dhirenb@iitb.ac.in) : Processing, properties and some novel applications of magnetic nanoparticles. Pramana J Phys 2005, 65(4), 663-79.

Magnetic nanoparticles have been prepared by various soft chemical methods including self-assembly. The bare or surface-modified particles find applications in areas such as hyperthermia treatment of cancer and magnetic field-assisted radioactive chemical separation. Presents some of the salient features of processing of nanostructured, magnetic materials of different sizes and shapes, their properties and some possible applications. The materials studied included metals, metal-ceramic composites, and ferrites.

15 illus, 1 table, 32 ref

013209   Ashtaputre S S et al (Dep STOPWORD Phys, Univ of Pune, Pune-411 007, Email: skk@physics.unipune.ernet.in) : Synthesis and analysis of ZnO and CdSe nanoparticles. Pramana J Phys 2005, 65(4), 615-20.

Zinc oxide and cadmium selenide particles in the nanometer size regime have been synthesized using chemical routes. The particles were capped using thioglycerol in case of ZnO and 2-mercaptoethanol in case of CdSe to achieve the stability and avoid the coalescence. Zinc oxide nanoparticles were doped with europium to study their optical properties. A variety of techniques like UV-Vis absorption spectroscopy, X-ray diffraction (XRD), photoluminescence (PL), X-ray phptoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) were used to carry out structural and spectroscopic characterizations of the nanoparticles.

4 illus, 18 ref

013208   Anuradha P;Rao E V;Hasan M F (Dep STOPWORD Phys, Kakatiya Univ, Warangal-506 009) : Growth and plastic anisotropy of EDS and ADI crystals. Bull pure appl Sci-Sect D 2005, 24(1), 69-75.

Studies on mouth and micro hardness on ethylene diamine sulphate (EDS) and ammonium dihydrogen phosphate (ADP) crystals are reported. Growth features (growth spirals and inclusions) in solution grown crystals are observed, the growth spirals observed on (001) faces of EDS arc indicative of anisotropic growth conditions. Plastic anisotropy on (001) and (010) faces is investigated by measuring the Knoop hardness by indentation method.

5 illus, 1 table, 14 ref

013207   Adeloye A B;Lubanzadio M (Phys Dep, Univ of Lagos, Lagos - Nigeria) : Effect of varying diamagnetic coupling on a modified hydrogen atom a uniform magnetic field. Bull pure appl Sci-Sect D 2004, 23(2), 111-16.

Hydrogen atom in a uniform magnetic field with variable diamagnetic coupling has been considered. Apart from finding a threshold value of the coupling for which the system becomes chaotic. Author has also deduced that the degree of chaoticity is not a monotonously increasing function of the coupling part of the potential.

2 illus, 19 ref

012109   Tiwari A K;Singh R A (Dep of Phys, Dr H S Gour Univ, Sagar-470 003, Email: rasinzh@yahoo.co.uk) : Normal vibrations and force fields for dimethylanilines. Asian J Spectrosc 2004, 8(3-4), 131-40.

Force field calculations for the planar and nonplanar vibrational mode of dimethylamins benzene have been carried out. A general valance force field consisting of 63 force constants for the three isomeric 2, 3-dimethylaniline, 2, 4-dimethylaniline and 2, 5-dimethylaniline have been determined to give satisfactory fit to the vibrational frequencies. A unique feature of the study is the determination of a single set of force constants to reproduce the vibrational frequencies for all the three isomers.

2 illus, 1 table, 28 ref

012108   Tiwari A K;Singh R A (Dep of Phys, Dr H S Gour Univ, Sagar-470 003) : Intramolecular force fields for chloromethylphenols. Asian J Spectrosc 2004, 8(3-4), 125-9.

Force field calculations for the planar and nonplanar vibrational modes have been carried out using earlier reported data for chloromethylphenols. A 22 principal and 31 interaction force constants force constants have been determined leading to a very reasonably consistent vibrational assignments for three isomers of chloromethylphenols. A unique feature of the calculation is the determination of a single set of force constants, which reproduces all the frequency of 3 isomers chloromethylphenols.

2 illus, 1 table, 18 ref

012107   Sisodia V;Kabiraj D;Jain I P (Cent Tor Non-Conventional Energy Resour, Univ of Raj, Jaipur-302 004) : Electrical properties of ion beam mixed Ti silicide at metal/Si interface. J Indian Inst Sci 2005, 85(3), 151-6.

Single-crystal n-Si substrtates of (100) orientation with a metal layer Ti 18 nm have been irradiated at room temperature with ¹⁹⁷Au of 95 MeV energy. High-energy ion beam mixing has been used to obtain mixing at Ihe interface. Titanium silicide (TiSi₂) formed as a result of the irradiation. The electrical propeties at the interface, containing the silicide layer, the room temperature I-V curves for the pristine samples and irradiated ones have been studied. Their room temperature resistance values are estimated.

^ssc4 illus, 21 ref

012106   Sibgatullin M E;Kharintsev S S;Salakhov M K (Phys Dep, Kazan St Univ, Kremlevskaya Str, 16 Kazan, Russia-420008) : Smoothening and denoising optical spectra of stars. Asian J Spectrosc 2004, 8(3-4), 91-100.

A comparative analysis of methods for eliminating background noise is attempted. An emphasis on the Savitzky- Golay method, Kaiser filtration and wavelet -based denoising is made; and argued that the behaviour of a singal at different scales (frequencies) plays a crucial role when the spectra are processed with the latter.

11 illus, 3 tables, 17 ref

012105   Refat M S;Sadeek S A;Khater H M (Dep of Chem Fac of Educ, Port-Said Suez-Canal Univ, Port Said, Egypt, Email: msrefat@yahoo.com) : Electronic, infrared, and <. Asian J Spectrosc 2004, 8(3-4), 111-24.

The interaction between o-toluidine and p-toluidine(π-donors) with the π-acceptors e.g. 3,5-dinitrobenzoic acid (DNB) and 2, 6-dichloroquinone-4-chloroimide (DCQ) results in the formation of 1:1 charge-transfer complexes [(o-tolidine) (acceptor)] and -[(p-toluidine) (acceptor)] as the final products. The final products of the reactions have been isolated and characterized using FTIR, ¹H NMR spectroscopy and elemental analysis as well as photometric titration. The stoichiometry and apparent formation constant of the complexes formed were determined by applying the conventional spectrophotometric molar ratio method.

5 illus, 3 tables, 19 ref

012104   Kargosha K;Noroozifar M (NO, Chem and Chem Engng Res Cent of Iran, Tehran, Iran) : Simultaneous flow-injection speciation of Cr(III) and Cr(VI) by solid-phase reactors and spectrophotometry. Asian J Spectrosc 2004, 8(3-4), 101-9.

A new, simple and low-cost flow injection system with two solid-phase reactors and spectrophotometric detection for speciation of Cr(III) and Cr(VI) has been proposed. A polyethylene mini-column (60 mm and 0.7 mm i.d.) filled with 1,5-diphenylcarbazide (25% m/m suspended on silica ges beads) in below, 1,5-diphenylcarbazone (25% m/m suspended on silica ges beads) in middle and Jones-reductor in up (reactor I), and another column filled only with 1,5-diphenylcarbazide (reactor II) were incorporated into a flow system. In reactor I, Cr(III) in samples (containing both Cr(III) and Cr(VI)) injected into 0.5 M H₂SO₄ as a carrier stream was reduced to Cr(II) by Jones-reductor, which was determined spectrophotometry at 548 nm by complexation with 1,5-diphenylcarbazone. Also, Cr(VI) was determined after complexation with 1, 5-diphenylcarbazide in reactors I and II in the same wavelength. The amount of Cr(III) in the same was estimated as the difference in the two determination from reactor I and reactor II. The calibration plots were up to 30 μg ml^-1 and 35 μg ml^-1 for Cr(III) and Cr(VI), respectively. Detection limits (3δ) were 70 μg l^-1 for Cr(VI) with a relative standard deviation <60>1.7%. The proposed system is suitable for determination of Cr(III), Cr(VI) and total chromium is spiked and effluent streams samples.

5 illus, 4 tables, 17 ref

012103   Fola Adio W (NO, , ) : Documentation services in developing countries: a case of Nigeria. Int Libr Movement 2005, 27(4), 194-204.

12 ref

012102   Dinesh Kumar M;Jamema S V;Saju S;Deshpande S; Deshpande D D (Dept of Med Phys, Tata Memorial Cent Tata Memorial Hosp, Parel, Mumbai-400 012, Email: hidinoo@yahoo.com) : Determination of beam quality correction factors (K_o,oo) for CD high tech chamber. J med Phys 2004, 29(4), 248-53.

The dosimetry formalism is slowly changing from air kerma to absorbed dose to water. CD High Tech chamber is widely used in India and TRS 398 does not provide K_o value for CD High Tech chamber. Determines the beam quality correction factor K_o for three cylindrical chambers of type CD High tech, PTW 30001 and FC65, for clinical high-energy photon beams of nominal energies 6, 10 and 15 MV. Cross calibration technique of ionization chamber is used to determine the beam quality correction factors. NE 2571 chamber is used as reference chamber. Theoretical calculations were made using the basic data available in TRS 277/TRS 398. Experimentally obtained values of K_o are compared with values of K_o from TRS 398 and TG 51. On comparison, maximum deviations of 0.4% for PTW 30001 chamber, and 0.7% for FC 65 chamber are obtained which validate this method to determine K_o at the user level. For CD High Tech chamber, it is observed that the maximum deviation of 0.3% is obtained between the calculated and the experimental values. Further, measured K_o values for CD High Tech chamber are compared with NE 2505 chamber. Physical characteristics of these two chambers are comparable. A maximum deviation of 0.5% is found between the K_o values of CD High Tech chamber and NE 2505 chamber. K_o values of NE 2505 can also be used for CD High Tech chamber, since the physical characteristics of both the chambers are nearly same.

5 tables, 6 ref

011105   Yadav S;Gupta V K;Om Prakash;Bandyopadhyay A K (NO, Natn Phys Lab, Dr K S Krishnan Road, New Delhi-110 012, Email: syadav@mail.nplindia.ernet.in) : Proficiency testing through interlaboratory comparison in the pressure range up to 70 MPa using pressure dial gauge as an artifact. J scient ind Res 2005, 64(10), 722-40.

Proficiency testing (PT), a quality control, provides an additional means to ensure quality of laboratory testing results. The primary objective of organizing PT is to assess laboratory's technical competence to perform measurements. Describes PT of 11 laboratories, nine accredited by National Accreditation Board for Testing and Calibration of Laboratories (NABL), having best measurement capabilities (<60> 0.25 % of full-scale pressure) by means of interlaboratory comparison using pressure dial gauge (5-70 MPa) as an artifact. This programme was identified by code number NABL-Pressure-PT003. National Physical Laboratory (NPLI), New Delhi coordinated this programme (February 2003-March 2004) and acted as a reference laboratory. The comparison was carried out at 14 arbitrarily chosen pressure points (5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65 and 70 MPa) throughout the entire pressure range (5-70 MPa). Out of the total 145 measurement results, 86 (59.31%) results were found in good agreement with the results of reference laboratory, NPLI, New Delhi. The relative deviations of the laboratories values with reference values were found almost well within the uncertainty band of the reference values (44.14% pressure points), within their combined uncertainty band (59.31% pressure points) and within their best measurement capabilities (80.34% pressure points). Since most of the laboratories have underestimated their measurement uncertainties, 40.69% measurement results were found out of the combined uncertainty band during this comparison. Overall, results were reasonably good being the first PT for all the participating laboratories. This exercise gives an opportunity to calibration laboratory to demonstrate its technical competence of routine calibration services rendered to clients and to have the measurement traceability to the national metrology institute, NPLI, New Delhi.

21 illus, 5 tables, 21 ref

011104   Vikram Singh;Manoj Kumar; (Dep of Phys, R B S Coll, Bichpuri, Agra- 283 105) : A new whistler recorder and analyzer developed at Agra*. Indian J Radio Space Phys 2005, 34(5), 349-52.

A new experimental set-up for recording and analysis of whistlers and VLF emissions has been developed at Agra, which is less expensive, automatic and time saving in comparison to earlier experimental set-up being used in different whistler stations in India. The new experimental set-up employs a crossed loop antenna, amplifiers, low pass filter, a sound card and PC with a software specially designed for recording and analysis of VLF data. Some examples of whistlers and VLF emissions recorded by the new set-up are presented and their frequency-time characteristics are discussed thoroughly.

4 illus, 16 ref

011103   Verma K D (Dep of Phys, Sri Varshney (PG) Coll, Aligarh-202 001, Email: kdverma@rediffmail.com) : Equation of state and thermal expansion coefficient for NaCl crystal under high pressure and high temperature. Indian J Phys 2005, 52(2), 863-7.

Tallon's model has been used for determining the volumes and thermal expansion coefficient for NaCl crystal upto a pressure of 50 kbar and in the temperature range of 300-773 K. The concept of the modified Gruneisen parameter has been adopted to obtain equation of state. The results obtained are found to present close agreement with the available experimental data.

3 tables, 30 ref

011102   Varshney D;Kinge R;Sharma P;Kaurav N;Singh R K (Sch of Phys, Vigyan Bhawan, Devi Ahilya University, Indore-452 017) : High pressure phase transformation and elastic behaviour of ZnX semiconducting compound. Indian J pure appl Phys 2005, 43(12), 939-51.

An effective interionic interaction potential to investigate the pressure induced phase transitions from zinc blende (B3) to rock salt (Bl) structure and anharmonic properties in ZnX [X = Se, S, Te] semiconductors has been presented. The elastic constants, including the long range Coulomb, Van der Waals (vdW) interaction and the short-range repulsive interaction of up to second-neighbour ions within the Hafemeister and Flugare approach, are derived as a first step. Both of the ions are polarizable, therefore the Slater-Kirkwood variational method is employed to estimate the vdW coefficients. It is inferred that vdW interaction is effective in obtaining the thermodynamical parameters such as the Debye temperature, Gruneisen parameter, thermal expansion coefficient and the compressibility. The major volume discontinuity in the pressure-volume phase diagram representing the structural phase transition from zinc blende to rock salt structure, is consistent as those revealed from earlier reports. It was found that short-range vdW attraction, long-range Coulomb repulsion, and short-range overlap repulsion in ZnX will contribute effectively to the mechanical properties and show similar results as those revealed from experiments.

5 illus, 1 table, 29 ref

011101   Vaid R;Padha N (Dep of Phys & Electron, Univ of Jammu, Jammu-180 006, Email: rakeshvaid@yahoo.co.in) : Comparative study of power MOSFET device structures. Indian J pure appl Phys 2005, 43(12), 980-8.

Comprehensive comparative study of various power MOSFET device structures designed and developed during the past decade has been presented. Various design issues related with power MOSFET have been studied to look into their on-resistance (RON) versus breakdown voltage (B_v) trade off. Some of the existing power MOSFET device topologies have been compared with respect to their R_ON-B_V The study reveals that the low-doped n- epi region which gives square law relationship between R_oN and B_v in the conventional power MOSFET is being constantly engineered for optimizing R_ON-B_V trade-off subsequently led to many structural modifications in its basic design giving rise to many new power MOSFET device structures such as SSCFET (Silicon Semiconductor Corp. FET), JBSFET (Junction barrier controlled Schottky FET), superjunction (SJ)/COOLMOS(tm) transistor, semi-superjunction devices and FLIMOSFET (power MOSFETs with vertical floating islands) so as to overcome the conventional silicon limit.

9 illus, 29 ref

011100   Tiwari V K;Kimothi A;Bhatnagar D;Saini J S; Saxena V K;Kumar P (Microwave Lab Dep of Phys, Univ of Raj, Jaipur-302 004) : Effect of air gap on the performance of circular sector antennas. Indian J Radio Space Phys 2005, 34(6), 417-23.

Theoretical analysis of a circular sector microstrip antenna having sector angle (α) and an air gap (h_a) between substrate material and ground plane is carried out by applying cavity-model-based modal expansion technique. Expressions for different antenna parameters are derived in TM₁₁ mode of excitation and the theoretical results are compared with simulated results. Average differences in computed and simulated resonance frequency, input impedance, directivity and bandwidth values for the sector geometry with air gap are found to be 1.3%, 10.25%, 0.75% and 1.9%, respectively. This validates the accuracy in proposed analysis technique for the present geometry.

10 illus, 3 tables, 11 ref

011099   Tiwari V K;Bhatnagar D;Saini J S;Kumar P (Microwave Lab Dep of Phys, Univ of Raj, Jaipur-302 004, Email: dbhatnagar_2000@redifmail.coni) : Investigation of radiation properties of a right isosceles triangular microstrip antenna. Indian J Radio Space Phys 2005, 34(5), 353-6.

Radiaton properties of a probe fed linearly polarized right isosceles triangular microstrip antenna (RITMA) with single feed point are experimentally investigated. Radiation patterns, return loss, bandwidth and gain results obtained are compared with theoretical results. The theoretical analysis is carried out by applying cavity model based modal expansion technique. A fairly nice agreement between computed and measured results is recorded that validates the accuracy and utility of proposed technique for the analysis of RITMA geometry.

4 illus, 8 ref

011098   Srivastava K K P;Sinha K K (Dep of Phys, T M Bhagalpur Univ, Bhagalpur-812 007) : Dielectric studies of polycrystalline(Sr,Fe)TiO₃ ceramics. Indian J pure appl Phys 2005, 43(11), 884-8.

The characteristic properties of polycrystalline (Sr,Fe)TiO₃ ceramics have been studied through Mossbauer, EPR, IR and differential scanning calorimetry because perovskite type dielectrics have useful applications in electronic industry. In Fe-doped materials, the small concentration of Fe atoms provides active centres that can be probed through Mossbauer and 'EPR methods which are precise enough to detect small lattice structural perturbations and yield valuable information. The work deals with their dielectric properties including dielectric relaxation time that is considered an important study from a theoretical angle. It is found that -the two-state Debye relaxation model is inadequate. These ceramics tend to behave like relaxors with ferroelectric transition temperature in the range 200-250°C depending upon iron concentration.

5 illus, 1 table, 15 ref

011097   Sivagurunathan P;Dharmalingam K;Ramachandran K (Dep of Phys, Annamalai Univ, Annamalai Nagar, Tamilnadu-608 002) : Molecular interaction studies of acrylic esters with alcohols. Indian J pure appl Phys 2005, 43(12), 905-10.

Hydrogen bonding between alcohols and acrylic esters in benzene has been studied by FTIR spectroscopic method. Utilizing Nash method the formation constant of the 1:1 complexes has been calculated. The formation constant and free energy change values vary with alcohol and ester chain length, which suggests that the proton donating ability of alcohols is in the order: 1-propanol <60> 1-butanol <60> 1-pentanol and the accepting ability of acrylic esters is in the order: methyl methacrylate <60> ethyl methacrylate <60> butyl methacrylate.

5 tables, 11 ref

011096   Shivnarayan;Sharma S;Vishvakarma B R (Dep of Electron Engng, Inst of Technol Banaras Hindu Univ, Varanasi- 221 005, Email: brvish@bhu.ac.in) : Analysis of slot-loaded rectangular microstrip patch antenna. Indian J Radio Space Phys 2005, 34(6), 424-30.

The analysis of a slot-loaded rectangular microstrip patch antenna using equivalent circuit concept is presented. The slot is taken as a capacitive reactance on the patch. It is found that the resonance frequency decreases with increasing slot width for a given slot length. The decrease in the resonance frequency is in the higher side for longer slot length, whereas it is on the minimum side for the lower slot length. It is found that VSWR remains almost invariant with slot width and slot length. The impedance increases almost linearly with the slot width, but inversely with the slot length.

8 illus, 1 table, 16 ref

011095   Sharma J P;Sekhon S S (Dep of Appl Phys, Guru Nanak Dev Univ, Amritsar-143 005, Email: sekhon_apd@yahoo.com) : Relative role of plasticizer and nano size fumed silica on the conductivity behaviour of PEO-NH₄PF₆ polymer electrolytes. Indian J Engng Mater Sci 2005, 12(6), 557-62.

Conductivity of proton conducting polymer electrolytes obtained by the complexation of ammonium hexafluorophosphate (NH₄PF₆) with polyethylene oxide, (PEO) increases with the addition of propylene carbonate (PC) (plasticized polymer electrolyte) and nano size fumed silica (nano composite polymer electrolytes). Plasticized polymer electrolytes have higher conductivity whereas nanocomposite polymer electrolytes have better mechanical properties. The simultaneous addition of PC and fumed silica leads to the formation of electrolytes with higher conductivity (4.50 x 10^-5 S/cm at 25°C) as well as better mechanical strength. The curved nature of log conductivity versus reciprocal temperature plot suggests the amorphous nature of these electrolytes and a small change in conductivity observed over the 20°C to 100°C temperature range is also suitable for their use in applications.

6 illus, 2 tables, 22 ref

011094   Shanti Kumari;Rafique S M;Mukherjee K K; Prasad H S (P G Dep of Phys, T M Bhagalpur Univ, Bhagalpur-812 007, Email: sm_rafq@yahoo.com) : Lattice dynamics of hcp metals through refined harmonic model potential (RHMP). Indian J Phys 2005, 52(2), 869-74.

The harmonic model potential (HMP), an improvement of Shaw and Heine-Abarenkov model, has been used in the past decades to study the phonon frequency and other physical properties of alkali metals with reasonable success. In case of hcp (hexagonal close packed) metals it was felt that some refinement is essential. This refined harmonic model potential (RHMP) has been used for the calculation of the phonon frequencies of hcp metals. Appreciable improvement in the result and reasonable agreement with experiment have been achieved.

5 illus, 6 tables, 36 ref

011093   Shanker J;Singh B P (Dep of Phys, Inst of Basic Sci, Khandari, Agra-282 002, Email: drbps@sancharnet.in) : Equations of state based on exponential functions for potential energy of solids. Indian J Phys 2005, 52(2), 857-61.

Equations of state (EOS) for solids based on exponential functions for potential energy are found to yield results for pressure-volume relationships in close agreement with the available experimental data as well as with the values obtained from the Hama and Suito EOS based on first-principles. Author has used equations of state based on exponential functions due to (i) Morse, (ii) Rydberg and (iii) Davydov. It is shown in the study that a limit of maximum compression exists for each solid corresponding to zero potential energy. This is a fundamental concept revealed from the nature of potential energy curve. The exponential functions for potential energy have been used to determine the compression limits for NaCl, MgO and iron. Strong evidence is given to support the predicted values of compression limits on the basis of seismological data and phase transformations. The results for pressure as a function of volume obtained for iron using the potential functions are found to present close agreement with the seismological data upto a pressure relevant to the inner core boundary of the earth.

1 illus, 3 tables, 20 ref

011092   Sengwa R J;Soni A (Microwave Res Lab Dep of Phys, J N V Univ, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Low frequency dielectric dispersion and microwave permittivities of Indian granites. Indian J Radio Space Phys 2005, 34(5), 341-348.

Complex dielectric permittivity ε*(ω) = ε'-jε" of 20 Indian granite samples from various localities in India were studied in the low frequency range 0.10-100 kHz and also at microwave frequency, i.e. 10.1 GHz at room temperature. All the studied dry samples showed the dielectric dispersion in the low frequency range. These are characterized by principal relaxation time with Cole-Cole dielectric dispersion model. The values of static dielectric constant ε_O, high frequency limiting dielectric constant ε∞, distribution parameter α, and relaxation time τ of these samples were determined from their Cole-Cole plots. The frequency dependent ac conductivity of these granite samples were also determined and discussed. The real part of dielectric constant ε'of dry granite samples at 10.1 GHz was found to be in the range 4.5-8.3. Clear convincing correlation was observed between the microwave frequency ε' values with the samples bulk density. The plots of ε' values versus bulk density of the studied granite samples were represented by two straight lines of different slopes. The density reduced microwave permittivity values ε'dr of granite samples were found to be in the range 1.81-1.99. For all the studied granite samples dielectric loss ε" was found to be less than 0.5 at microwave frequency. Microwave permittivities of porous samples with water saturation were also measured and these values were compared with the permittivity values computed from the dielectric mixing equation, complex refractive index model and the self-similar model using the microwave permittivities of dry samples and water.

5 illus, 2 tables, 37 ref

011091   Sengwa R J;Soni A (Microwave Res Lab Dep of Phys, J N V Univ, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Dielectric dispersion and microwave dielectric study of marbles in support of radar investigations. Indian J pure appl Phys 2005, 43(10), 777-82.

Dielectric permittivity ε' and loss ε" of nine marble samples collected from open marble mines of Makarana, Rajsamand, Ambhaji and Kesariyaji of Rajasthan were studied in the frequency range 100 Hz-100 kHz and also at 10.1 GHz at room temperature. It is found that the ε' values of dry marbles decrease with increase in frequency in the range 100 Hz-100 kHz. All the studied marbles are governed by the Cole-Cole dielectric dispersion. The values of static dielectric constant ε_o, high frequency limiting dielectric constant ε∞, dielectric relaxation strength Δε, distribution parameter α, and relaxation time for dipole rotation τ were determined from the complex Cole-Cole plots. All these samples have a values greater than 0.5 and their Δε values vary significantly. Further, wide variation in ac conductivity σ is also observed for different samples. The effect of sample bulk density and variation in the chemical composition on low frequency and microwave permittivity of the studied marbles have been recognized. The measured values of dielectric permittivity of these marbles were also compared and discussed with the earlier reported ε' values of marbles and limestones of other regions. The precise microwave dielectric measurements. of marbles and recognization of their dependence on petrological and chemical composition are interesting and can be used in support of radar investigations of the Earth's geology.

4 illus, 2 tables, 29 ref

011090   Sengwa R J;Sankhla S;Abhilasha (Microwave Res Lab Dep of Phys, J N V Univ, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Interaction effect on molecular dynamics of some polar solvents in poly (vinyl pyrrolidone) matrix studied by microwave dielectric relaxation measurements in dilute solutions. Indian J Phys 2005, 52(2), 879-86.

Microwave dielectric relaxation measurements on poly(vinyl pyrrolidone) (PVP) mixture of ethyl alcohol (EA), poly (ethylene glycol) (PEG200 and PEG400), dimethyl sulphoxide (DMSO) and dimethyl formamide (DMF) with PVP concentration variation have been measured in dilute solutions of dioxane at 10.1 GHz and at 35°C. The analysis of the results, which is particularly aimed at information on hetero-association, confirms the existence of different homogeneous and heterogeneous species in dilute solutions. The PVP concentration-dependent relaxation time of the PVP-polar solvents mixture confirms that hindrance to the dynamics of polar solvent molecules is influenced by the solvent interactions with PVP matrix. In hydroxyl group/s containing solvents, hindrance to their molecular reorientation increases at higher PVP concentration but the interactions of DMSO and DMF with PVP matrix facilitates their dynamic in dilute solutions of dioxane over wide range of PVP concentrations.

2 illus, 2 tables, 41 ref

011089   Sarma R;Mazumdar N;Das H L (Dep of Phys, Gauhati Univ, Guwahati-781 014, Email: hld_guphys@rediffmail.com) : Mobility activation in polycrystalline ZnTe thin films. Indian J Phys 2005, 52(2), 909-12.

Effect of illumination on mobility has been studied from the photocurrent decay characteristics of thermally evaporated zinc telluride thin films evaporated on glass substrates held at room temperature. Study indicates that the mobilities of the carriers of different trap levels are activated due to the energy of incident illumination, which results the existence of two distinct trap depths. In each trap depth, the energy of the trap increases linearly. It infers that there is a linear distribution of trap of different energies below the conduction band.

5 illus, 15 ref

011088   Salvi S V;Pimpale S S (Dep of Phys, The Inst of Sci, Mumbai-400 032) : Potential-variation of a time effect on the average of counts in argon at a low pressure subjected to low frequency silent electric discharges. Indian J pure appl Phys 2005, 43(12), 931-8.

A series of observations at a definite kV (rms) was taken for the time-variation of discharge counts in which the arithmetic mean of counts in dark (εC_D)/n; in light (εC_{L)/n and their associated net effect (εΔC)/n [= (εCL)/n - (εCD)/n] of irradiation were calculated; after that the discharge tube (1) was short aged for 5 min at 2.45 kV (rms) and the discharge was then discontinued; re-applying the same potential kV (rms) to the same tube, the variation with time of exposure to discharge of counts was again recorded and (sigmaΔC)/n re-determined as previously. It has now been observed that almost always (εΔC)/n shows a greater value in the earlier that in the latter series. Thus, several series of experiments were carried out at different values for the applied potential in each of which (εΔ)/n was measured as a function of the applied potential increased progressively, at a constant window width of 0.07 kV(rms), to a maximum. Similarly, the results in a series of comparative measurements for two discharge tubes have been reported. It was observed that the increase of (εΔC)/n as a result of ageing, i.e. due to previous exposure to the discharge, was very appreciably larger in the case of a discharge tube (1) which had been rendered comparatively insensitive in regard to the average effect of irradiation, than a fresh one which showed the familiar behaviour of an irradiation. The average light effect (εΔC)/n decreased with ageing, and disappeared finally. It revived to its original, value after allowing a period of rest.of 24 hr. Threshold voltage, Vg, in aged tube was appreciably smaller than that in the freshly prepared one. This is ascribed to a lowering of the electrode surface work function due to ionic bombardment under discharge. + (εΔC)/n inverted to -(ΔC)/n with ageing and then decreased. The increase in + (εΔC)/n with ageing is attributed to an enhanced photo-electron emission caused by the decrease in the work function. The decrease in -(εΔC)/n is ascribable to the deconditioning of the adsorption like boundary layer formed during discharge. The results show that -(εΔC)/n is associated with a decrease in ionic mobility. This lends support to the Joshi's theory for the mechanism of-(εΔC)/n, n being the total number of readings taken between counts and exposure -time at each voltage.}

2 illus, 1 table, 25 ref

011087   Roshan Lal;Sharma N D (Dep of Phys, Kurukshetra Univ, Kurukshetra-136 119) : Infrared spectroscopic study of zinc doped iron borate glass. Indian J pure appl Phys 2005, 43(11), 828-32.

The infrared absorption spectra of xZnO(40-x)Fe₂O₃.60B₂O₃ glasses (x = 0, 10, 15, 20 and 30 mol% of ZnO) have been investigated to find out the role played by zinc on the structure of these glasses. ZnO was gradually introduced to replace Fe₂O₃ in the series of zinc doped iron borate glasses containing 60% B₂O₃. The structural changes were inferred by monitoring the infrared spectra of these glasses in the range 200-4000 cm^-1 by KBr technique. Very small change in absorption bands may occur on addition of ZnO impurity in the series of zinc doped iron borate glasses. No boroxyl ring formation is observed in the structure of these glasses. Similarly, tetrahedral formation of zinc is not observed. The absence of absorption band corresponding to a frequency of 806 cm^-1 is attributed to the progressive substitution of boroxol ring by triborate (BO₃) and tetraborate (BO₄) groups.

1 illus, 1 table, 19 ref

011086   Ray D K;Himanshu A K;Sinha T P (Dep of Radiotherapy, Chitranjan Natn Cancer Inst Kolkata-700 026, Kolkata-700 009) : Study of impedance spectroscopy conducting polymer prepared with the use of water soluble support polymer. Indian J pure appl Phys 2005, 43(10), 787-93.

Intrinsically conducting polymer (ICP), polyaniline (PANI) is synthesized by chemical oxidative polymerization process with the help of water soluble support polymer poly-vinyl alcohol (PVA). The field dependence of the dielectric response is measured in the frequency range 50 Hz-1 MHz and temperature range 140-318 K. The frequency dependence of the imaginary impedance (Z") is found to obey an Arrhenius law with the activation energy of 0.0176 eV. An analysis of real and imaginary parts of dielectric permittivity, conductivity formalism and impedance (Z) with frequency and temperature is performed, showing the polydispersive nature of the sample as confirmed by Cole-Cole plot as well as the scaling behaviour of the Z". The frequency dependent electrical data are discussed in the context of models for dc and oc transport in PANI-PVA composite, with the results supporting hopping of charges among positively charged polaron and bipolaron states. These results elucidate that there is an increased coupling among the local dipolar motions (short-range order localized motion).

8 illus, 92 ref

011085   Rao D S;Vijaya Kumar T V;Subba Rao S; Prabhakar S;Bhaskar Raju G (NML Madras Cent, CSIR Madras Complex, Taramani, Chennai-600 113, Email: nmldsr@yahoo.co.in) : Alteration characteristics of the Manavalakurichi beach placer ilmenite, Tamil Nadu. J appl Geochem 2005, 7(2), 195-200.

The mineralogy and alteration characteristics of beach placer ilmenite from the Manavalakurichi coast were investigated by optical microscopy and electron probe microanalysis. Mineral chemistry by electron probe micro-analysis indicated enrichment of TiO₂, MgO, Al₂O₃, Cr₂O₃, SiO₂, K₂O, V₂O₅, CaO and Na₂O in the altered products of ilmenite, while there was a loss of iron oxide, maganese oxide and zinc oxide from the ilmenite grains during weathering leading to leucoxene and pseudorutile formation.

2 illus, 3 tables, 21 ref

011084   Ramasamy V;Ponnusamy V;Hemalatha J; Meenakshisundaram V;Gajendiran V (Dep of Phys, Annamalai Univ, Annamalainagar-608 002, Email: srsaranram@rediffmail.com) : Natural radioactivity and radiological hazards caused by different marbles of India. Indian J pure appl Phys 2005, 43(11), 815-20.

Samples used in the study are of various coloured varieties of marbles collected from marble dealers. The specific activity concentration of ²³⁸U, ²³²Th and ⁴⁰K has been determined by gamma ray spectrometry. The materials showed concentrations of ²³⁸U, ²³²Th and ⁴⁰K which were found to be dramatically variable depending on mineral content and type of formation. Using FTIR and thin section analyses, quartz, feldspar, calcite and mafic minerals present in the samples have been determined quantitatively. From experimental data, it can be seen that the geochemical parameters such as SiO₂ or mafic minerals or CaCO₃ may be considered to be an appropriate index to select the marbles of low radiological risk. The average specific activities of ⁴⁰K are found to be higher than ²³²Th and ²³⁸U. The ratio of Th/U was calculated and correlated. Assessment of radiological hazards was made by calculating radium equivalent activities, external and internal hazard indices which were found to vary from 30.92 to 54.45, 0.08 to 0.14 and 0.10 to 0.17 Bq/kg, respectively. The observed values are lower than the recommended limits.

2 illus, 2 tables, 19 ref

011083   Ramasamy V;Ponnusamy V;Hemalatha J (Dep of Phys, Annamalai Univ, Annamalai Nagar-608 002, Email: srsaranram@rediffmail.com) : Study on effect of baking of natural calcitic crystalline limestones at various temperatures through FTIR, XRD and TG-DTA analysis. Indian J Phys 2005, 52(2), 847-55.

Transmission FTIR technique was made use of to identify the minerals in recently excavated limestones, to study the chemical structure of calcite, to distinguish between different types of clay minerals, and to obtain the composition and structural changes of calcite upon heating at various temperatures. KBr pressed disk technique was found to be very useful for a routine characterization of minerals, for examination of structural modification of calcite and formation of new minerals during heating. The characterization of these minerals was also attempted using XRD and TG-DTA analysis. The minerals, upon heating the limestone were identified as metakaolinite, calcium oxide, calcium hydroxide, anorthite and aragonite. The structural transformation of D_3h calcite to unidentate formation of C_s aragonite at 850°C and then to bidentate formation of C_2v aragonite at 1050°C were illustrated. IR peak at 1423 cm^-1 at room temperature (RT), indicates calcite crystallization under low pressure during the formation rock. The results obtained through these studies dictate the reason for loss of TSL sensitivity above 700°C.

3 illus, 30 tables, 22 ref

011082   Ramasamy V;Mullainathan S;Murugesan S (Dep of Phys, Annamalai Univ, Annamalainagar-608 002, Email: srsaranram@rediffmail.com) : Natural radioactivity measurements in sediment samples of Palaru river, Tamil Nadu, India. Bull pure appl Sci-Sect F 2004, 23(1-2), 41-5.

Concentration of primordial radionuclides in sediment samples of Palaru river. Tamilnadu, India, has been measured from the gamma ray spectrum of the sediments. The mean activities of ²³⁸U, ²³²Th and ⁴⁰K are 10.72, 38.28 and 727.50 BqKg^-1 dry weight, respectively. The mean absorbed dose rate is 59.28 nGyh^-1, corresponding to an annual effective dose equivalent ranges from 41.84 to 245.23 nGyh^-1. The results have been compared with other global radioactivity measurements and evaluations.

1 illus, 1 table, 7 ref

011081   Ramalingam K;Sasibhusana Rao G;Ramakrishna K ;Sarma A D (Airports Auth of India, Hyderabad Airport, Hyderabad-500 016, Email: ad_sarma@yahoo.com) : Effect of environmental changes on the performance of ILS located at Hyderabad airport. Indian J Radio Space Phys 2005, 34(6), 431-4.

In civil aviation, the existing precision approach (PA) landing system equipment has certain limitations due to ground environment, which affects the performance of the equipment. The effect of changes in the environment conditions surrounding the airport on Instrumental Landing System (ILS) course structure has been presented by comparing the calibrated and measured data at Hyderabad airport (India). The field strength data are acquired using the NORMAC ILS signal field test receiver and compared with the calibration aircraft (AVRO HS-748) data. Performance of the existing ILS is analyzed and the results confirm the effect of environmental changes on the ILS course structure.

1 illus, 5 ref

011080   Rajesh K R;Menon C S (Sch of Pure and Appl Phys, Mahatma Gandhi Univ, Kottayam 686 560-Kerala, Email: rajthinfilms@yahoo.co.in) : Electrical and optical properties of vacuum deposited ZnPc and CoPc thin films and application of variable range hopping model. Indian J pure appl Phys 2005, 43(12), 964-71.

Sandwich and planar structures have been fabricated using zinc phthalocyanine (ZnPc) and cobalt phthalocyanine as active layers and gold (Au) as electrodes by thermal evaporation method. The permittivity e is determined from the dependence of capacitance on film thickness. J-V characteristics of Au/ZnPc/Au and Au/CoPc/Au structures at room temperature have been performed. Thermally generated hole concentration p₀, hole mobility μ_p, total trap concentration N_t and depth of the trap level have been estimated. The activation energies of the films have been determined from the Arrhenious plots of In ρ versus 1000/T. Employing the variable range hopping model, hopping conduction parameters have been calculated. The absorption and reflectance spectra of ZnPc and CoPc thin films deposited at room temperature have been recorded in the spectral range 300-900 nm. The optical band gaps of the films have been determined from the α² versus hv graph. The optical constants n and k have been found. The real and imaginary parts of the optical dielectric constant ε_l and ε₂ have been calculated.

11 illus, 5 tables, 27 ref

011079   Rajarajan K;Selvakumar S;Joseph P;Gulam Mohamed M;Vedeha potheher I;Sagayaraj P (Dep of Phys, Loyola Coll, Chennai-600 034, Email: psagayaraj@hotmail.com) : Mechanical, dielectric and photoconducting properties of a novel non-linear optical crystal. Indian J pure appl Phys 2005, 43(12), 926-30.

Non-linear optical single crystals of cadmium mercury tetrathiocyanate dimethylsulphoxide [CdHg(SCN)₄(H₆C₂0S)₂], (CMTD) were conveniently grown from a DMSO-water mixed solvent by slow solvent evaporation technique. The crystals were characterized by single crystal X-ray diffraction and FT IR. The grown crystals were also subjected to microhardness, dielectric and photoconductivity studies. The microhardness studies indicate that the Vickers hardness number of the crystal decreases with increase in applied load. The dielectric response of the crystal with varying frequencies is studied and reported. The photoconductivity studies confirm that the title compound has negative photoconducting nature.

6 illus, 1 table, 14 ref

011078   Rai A;Rai V K (Dep of Chem, Jagatpur P.G. Coll, Varanasi, Email: vineetkrrai@yahoo.co.in) : Optical properties and upconversion in Pr<. J Indian Chem Soc 2005, 82(8), 697-700.

Absorption and the fluorescence spectra of Pr³⁺ ion doped in aluminium, barium, calcium fluoride (ABCF) glass have been studied. Judd-Otelt theory has been used to derive the optical parameters viz. the oscillator strength, transition probability, branching ratio, stimulated emission cross-section etc. Author has also calculated nephelauxetic effect, covalency and bonding parameters for Pr³⁺ in the present lattice. A broad band upconversion has been observed at different wavelengths throughout the visible region when pumped with 810 nm radiation from a Ti-Sapphire laser.

4 illus, 4 tables, 4 ref

011077   Prem Anand D;Selvakumar S;Ambujan K;Rajarajan K;Gulam Mohammed M.;Sagayaraj P (Dep of Phys, Loyola Coll, Chennai 600 034) : Growth and characterization of pure and aniline doped benzoy glycine single crystals. Indian J pure appl Phys 2005, 43(11), 863-8.

Optically good quality single crystals of organic non-linear optical pure benzoyl glycine (BG) and aniline doped BG of dimensions up to 5x4.5x5 mm³ and 3x3.5x2.5 mm³, respectively, are grown by solution growth technique. The grown crystals are characterized by single crystal XRD, FTIR, optical absorption, thermogravimetric(TG) analysis, microhardness, dielectric and photoconductivity studies. The microhardness studies suggest that the aniline substituted crystals have improved Vickers hardness number (VHN) values than the pure ones. The Non-linear Optical (NLO) test confirms the second harmonic signal generation in both pure and doped samples. The thermal studies of the pure and doped BG crystal indicate a marginal increase in the thermal stability of the doped crystal. The dielectric response of the sample is studied in the frequency region of 50 Hz - 500 kHz and the influence of aniline substitution on the dielectric behaviour has been investigated. Photoconductivity studies of pure and doped BG crystal reveal the positive photoconducting nature.

9 illus, 2 table, 15 ref