011076   Prasad P B V;Shashikanth P B (NO, SR Res Lab for Stud in Crystallization Phenomena, 10-1-96, Mamillaguda, Khammam-507 001, Email: prasadpbv_kmm@rediffmail.com) : Laser light scattering microscopy: Interpretation of images. Indian J Engng Mater Sci 2005, 12(6), 591-4.

Images obtained through laser light scattering microscopy are examined from the viewpoint of their acceptability as true representatives of the surface features. This is accomplished by considering the parameters that can modify the images. The meaning of laser light scattering microscopy (LLSM) images is explained, by comparing them with the monochromatic-incoherent light microscopy (MILIM) images and superimposed images. The changes induced in grains by slow increase in temperature are explained, in terms of modification of (i) surface of grain and (ii) grain itself (around and after solid-liquid phase transition).

3 illus, 13 ref

011075   Pandey V K;Vishvakarma B R (Dep of Electron Engng, Inst of Technolosy, Banaras Hindu University, Varanasi- 221 005, Email: brv@bhu.ac.in) : Electronic scanning in linear active antenna array. Indian J Radio Space Phys 2005, 34(5), 357-62.

Beam scanning characteristics of 1x4 linear Gunn-integrated active antenna array are investigated by varying the bias voltages of the different elements in the array keeping the side lobe level at least 10 dB down the main beam level. The optimization of beam scanning by varying the bias voltage of all the four elements simultaneously exhibited a beam scanning of 40° with power deviation of 1.85 dB in main beam, which is better than the earlier reported data.

9 illus, 3 tables, 18 ref

011074   Pal B;Singh J (Dep of Appl Sci, C R St Coll of Engng, Murthal (Sonepat)-131 039) : Dielectric tensor theory of electric field gradient in dilute transition metal based alloys: Application to vandium allys. Indian J pure appl Phys 2005, 43(12), 972-6.

The electric field gradient (EFG) in dilute alloys consists of two contributions valence effect and size effect EFGs. In the estimation of valence effect EFG an electrostatic screening approach is used to evaluate impurity scattering potential in transition metal (TM) based alloys. The dielectric tensor is inverted using the mixed band scheme where S-electrons are represented in free electron approximation and d-electrons in simple tight binding approximation. In this scheme the exact expression is obtained for the excess impurity potential ΔV(r) which consists of isotropic and anisotropic parts. The latter is the manifestation of local field (LF) effects in TM based alloys. The numerical results for ΔV(r) are obtained for vanadium (V) alloys with Ti, Cr, Mn, Fe, Mo and W impurities using non-interacting model band structure. The size effect contribution to EFG is evaluated in the elastic continuum approach. The EFG is calculated for the above mentioned V-alloys including the LF effects. The calculated results for EFG are consistent with experimental predictions and suggest that both the valence and size effects are equally important to explain the experimental results.

s, 2 tables, 21 ref

011073   Olowofela J A;Adegoke J A (Dep of Phys, Univ of Ibadan, Nigeria, Email: adegokeja@yahoo.com) : A laboratory study of the effects of porosity and bed tilting on the discharge rate of groundwater. Indian J Phys 2005, 52(2), 893-7.

Study of movement of underground water helps to predict the extent of flow in as much as author can determine the volume rate among other things. Sand samples from river bed were used as porous media, a laboratory experiment was set up to look at longitudinal dispersion in term of volume of liquid flowing across a unit cross sectional area per unit time in these materials. Water was made to flow through a cylindrical pipe drilled sideways at intervals. Values of pressure were taken at regular interval and using appropriate basic equations, the volume flux rate was determined at various angles of tilt, from which volume rate of flow was also determined. A graph of volume rate of flow against angle of tilt gives the value of volume rate of flow as 1.00 '10^-10 m³/s irrespective of porosity and permeability of the medium provided that the angle of tilt is 1.42°.

9 illus, 3 tables, 6 ref

011072   Nallasamy P;Mohan S (Dep of Phys, Bharathidasan Govt. Coll for Women, Pondicherry-605 003) : Vibrational spectroscopic characterization of form II poly(vinylidene fluoride). Indian J pure appl Phys 2005, 43(11), 821-7.

The Fourier transform Raman (FT-Raman) and infrared absorption (FTIR) spectra of form II poly(vinylidene fluoride) have been recorded and analysed. A complete spectral analysis, assignments to observed bands, normal coordinate analysis and discussion of the spectra have been presented. The computed spectrum is in excellent agreement with experiment. The potential energy distribution (FED) is evaluated from respective potential constants to analyse the purity of the modes.

4 illus, 1 table, 23 ref

011071   Naik L R;Math N N (Dep of Phys, Karnataka Univ, Dharwad-580 003, Email: nnm31@rediffmail.com) : Photo physical properties of 8-hydroxy quinoline. Indian J pure appl Phys 2005, 43(10), 743-9.

Steady state absorption, fluorescence excitation and emission spectra of 8-hydroxy quinoline (8-HQ) have been studied in a wide range of solvents of varying dipole moments. The dependence of fluorescence emission on concentration and excitation wavelength indicates the existence of two different emitting species in equilibrium. The fluorescence quantum yield exhibits a substantial solvent dependence. The high quantum yield observed in polar aprotic solvents such as dimethyl formamide and dimethyl sulphoxide might be due to severe overlapping of electronic transitions of various species/single species. The fluorescence and emission spectra of 8-HQ in various solvents exhibit dual fluorescence in the region 330-410 nm. The fluorescence emission of 8-HQ in pure dimethyl formamide, dimethyl sulphoxide and propanol solvents measured as a function of concentration in the range 10x10^-6 to 5x10^-4 mol dm^-3 displays a clear iso-emissive point at 395 nm while in binary mixture of propanol and dimethyl formamide, iso-emissive point is obtained around 410 nm for excitation wavelength of 290 nm. This finding reveals the formation of two stoichiometric hydrogen-bonding complexes, namely, 1:1 and 1:2 complexes in the ground and excited state.

4 illus, 2 tables, 20 ref

011070   Misra A;Kumar P;Srivastava R;Dhawan S K; Kamalasanan M N;Chandra S (OLED Lab Polymeric & Soft Mater Sect, Natn Phys Lab, Dr K S Krishnan Road, New Delhi- 110012) : Electrochemical and optical studies of conjugated polymers for three primary colours. Indian J pure appl Phys 2005, 43(12), 921-5.

The Cyclic Voltammetry investigation and optical properties of some of the commonly used conjugated polymers for the fabrication of organic LEDs, like poly [2-methoxy 5- (2'-ethylhexyloxy)-l,4-phenylenevinylene] (MEH-PPV), poly [2,3-bis (2-ethylhexyloxy)l,4-phenylenevinylene] (BEH-PPV) and poly[(9,9'-di(2'-ethylhexyl) fluoren-2,7-yleneethynylene] (PFE) for three principal emission colours red, green and blue, respectively have been reported. Both oxidation and reduction potentials of polymers were determined under the same experimental conditions to estimate the ionization potential (Ip: energy of Highest Occupied Molecular Orbital) and electron affinity (E_a,: energy of Lowest Unoccupied Molecular Orbital). The optical band gaps of the polymers were obtained from their optical absorption spectra. A comparative study of the electrochemical and optical bandgap of the polymers has been made. The photoluminescence (PL) of She polymers has also been studied.

4 illus, 2 tables, 19 ref

011069   Mehta N;Kushwaha V S;Kumar A (Dep of Phys, Harcourt Butler technol Inst, Kanpur-208 002, Email: dr_ashok_kumar@yahoo.com) : Calorimetric studies of thermal crystallization in glassy Se₈₀Te₂₀ and Se₈₀In₂₀ alloys. Indian J Engng Mater Sci 2005, 12(6), 571-6.

Different methods have been used by various workers to determine the activation energy of thermal crystallization (E_c) in chalcogenide glasses using non-isothermal DSC data. Crystallization kinetics of two important binary alloys Se₈₀Te₂₀ and Se₈₀In₂₀ is studied, using non-isothermal DSC data. DSC thermograms of these alloys have been taken at five different heating rates. The values of activation energy of crystallization (E_c) have been determined by four different methods, i.e., Kissinger's relation, Matusita and Sakka theory, Augis and Bennett's approximation and Ozawa's equation. The results obtained have been compared with each other to see the effect of using different methods in the determination of E_c. The composition dependence of E_c has also been discussed.

6 illus, 4 tables, 37 ref

011068   Mehan N;Gupta V;Sreenivas K;Mansingh A (Dep of Phys and Astrophys, Univ of Delhi, Delhi-110 007, Email: navinmehan@yahoo.com ) : Surface plasmon resonance based refractive index sensor for liquids. Indian J pure appl Phys 2005, 43(11), 854-8.

Surface plasmon resonance (SPR) refractive index sensor for liquids was fabricated and characterized. A thin silver (Ag) film (545 Angstrum) was deposited on a prism face and surface plasmon modes were excited along the interfaces of Ag and air, Ag and water and Ag and sugar solutions by prism-coupling using a He-Ne laser. The experimental SPR reflectance curves shifted continuously with increase in sugar concentration. Theoretical fitting of the SPR dip angles yielded the dielectric constant of Ag and refractive indices of water and sugar solutions. A maximum sensitivity of 1.4 X 10^-4 R.I.U. (refractive index units) was achieved with SPR dip angle as variable parameter. With SPR reflectance as variable parameter at a fixed angle, the maximum sensitivity was 3.9 x 10^-5 R.I.U. in a selected narrow range of refractive index.

7 illus, 7 ref

011067   Mattoo B A;Malik M A (Dep of Phys, S P Coll, Srinagar-190 001, Email: bamattoo@yahoo.com) : Charge imbalance generated by tunnel injection in superconductors. Indian J pure appl Phys 2005, 43(11), 873-83.

Using quasi-classical Green function, charge imbalance relaxation rates in tunnel injection experiments are calculated. It yields accurate results even when pair-breaking rate is comparable with the gap frequency.

4 illus, 1 table, 23 ref

011066   Mahesh M J;Gopalakrishna J S;Ashamanjari K G (Dep of Stud in Geol, Univ of Mysore, Manasagangotri, Mysore-570 006, Email: gopalakrish2004@yahoo.com) : Soft hydrothermal synthesis, morphology and characterization of disodium nickel pyrophosphate crystals: Na₂NiP₂O₇. Indian J pure appl Phys 2005, 43(12), 952-7.

Na₂NiP₂O₇ crystals were synthesized by soft hydrothermal rout at moderate pressure-temperature conditions.Highest degree of crystallinity observed at critical concentration of initial components and beyond which the crystallinity collapse sharply to minimum. Solubility studies revealed positive thermal coefficient with relatively high enthalpy in H₃PO₄. Magnetic results indicated that it is a frequency dependent paramagnetic material.

7 illus, 2 tables, 17 ref

011065   Mahapatra U S;Roy G S;Tripathy S;Maharana L (Dep of Phys, K B D A V Coll, Nirakarpur-752 019) : Evaluation of dipole moment of hydrogen bonded complexes of alcohols with amines. Indian J Phys 2005, 52(2), 913-16.

The formation of hydrogen bonded complexes in binary mixtures of n-butanol - n-butyl amine and n-propanol - n-propyl amine have been studied at radio frequency of 45 5 kHz at temperature 303.16 K. The dipole moment of the complex μ_ab, interaction dipole moment Δμ, and induced polarization P_ab in these systems have been evaluated from bond angle data. The results indicate that complexation is due to charge redistribution. The values of Δμ, μ_ab and p_ab are found to be greater for n-propanol-n-propyl amine system.

4 illus, 2 tables, 15 ref

011064   MadhaviLatha K;Badarinath K V S (For & Ecology Div, Natn Remote Sens Ag, Balanagar, Hyderabad-500 037) : Influence of nationwide truck strike on black carbon aerosols over urban environment of Hyderabad, India. Indian J Radio Space Phys 2005, 34(6), 435-7.

Black carbon (BC) aerosols have a major impact on human health besides global and regional climate. Measurements on spatial distribution of BC remains poor and severely hampers attempts to assess its radiative effects and the situation can be improved by more measurements of BC aerosols across the globe. A study has been carried out in the urban area, Hyderabad to assess the impact of nation-wide truck strike in August 2004 on ambient BC concentrations. The results indicate significant reduction in the BC loading associated with the withdrawal of the trucks. The decrease in BC concentrations has been observed to be gradual while the recovery was almost immediate after the strike was called off. The study provides information on influence of anthropogenic activities such as absence of diesel trucks on BC aerosols in urban areas.

2 illus, 13 ref

011063   Kannappan V;Santhi R J (Postgrad and Res Dep of Chem, Presidency Coll, Chennai-600 005) : Ultrasonic study of induced dipole-dipole interactions in binary liquid mixtures. Indian J pure appl Phys 2005, 43(10), 750-4.

Induced dipole-dipole interactions have been studied in binary liquid mixtures of pyridne, chlorobenzene, bromobenzene and nitrobenzene with p-xylene by measuring the ultrasonic velocity (U), density (ρ) and viscosity (η) values at 298 K at various concentrations. Acoustical parameters such as adiabatic compressibility (β), free volume (V_f), internal pressure (π_i,), intermolecular free length (L_f), absorption coefficient (α/f²), relaxation time (τ), Rao constant (R), cohesive energy (CE) and molecular interaction parameter with respect to velocity (xu) have also been calculated. The acoustical parameters can be used to assess the strength of induced dipole-dipole interactions in the four systems studied. The strength of dipole-induced dipole attractions correlates with dielectric constant and dipole moment of the polar compounds.

2 illus, 4 tables, 21 ref

011062   Joshi B C;Dhondiyal C C (Dep of Phys, Kumaun Univ, Almora Campus. Almora (Ultaranchal)) : Excitation energy transfer between Eu<. Indian J pure appl Phys 2005, 43(12), 918-20.

Non-radiative energy transfer from Eu³⁺ to Tm³⁺ has been studied by observing the steady state emission of Eu³⁺ with varying concentration of Tm³⁺ in zinc phosphate glass. It has been observed that Eu³⁺ion emission intensity decreases with increasing Tm³⁺ concentration resulting in a non-radiative energy transfer from Eu³⁺ to Tm³⁺ whereas energy transfer from Tm³⁺ to Eu³⁺ was not observed between donor and acceptor ions. This energy transfer has been explained on the basis of cross-relaxation of energy. The energy transfer mechanism and other parameters related to energy transfer between E³⁺ and Tm³⁺ have been computed.

4 illus, 1 table, 14 ref

011061   Jayarama A;Dharmaprakash S M (Dep of Phys, Mangalore Univ, Mangalagangotri-574 199, Email: smdharma@yahoo.com) : Effect of thiourea on the crystal structure of ammonium dihydrogen phosphate. Indian J pure appl Phys 2005, 43(11), 859-62.

The crystal structure of thiourea mixed ammonium dihydrogen phosphate (ADP) was determined at 116(2) K. Temperature variation of thermal vibrations signifies the existence of a disordered character of atoms. The structure was solved using SHELXS-97 and refined with SHELXL-97. A direct-method solution was calculated which provided positions of non-hydrogen atoms from the E-map. Full-matrix least squares/difference Fourier cycles were performed to locate the hydrogen atoms. All non-hydrogen atoms were refined with anisotropic displacement parameters. The unique hydrogen on the nitrogen and the half-weight hydrogen on the oxygen atom were refined as isotropic contributors in the final cycles of refinement. It follows that the mechanism of the phase transition is dominated by the disorder-like motion of the NH₄⁺ ion rather than the PO₄ tetrahedron.

2 illus, 4 tables, 20 ref

011060   Ibrahim M;Nada A;Kamal D E (Spectroscopy Dep, Natn Res Cent, Dokki, Cairo, Egypt) : Density functional theory and FTIR spectroscopic study of carboxyl group. Indian J pure appl Phys 2005, 43(12), 911-17.

Both molecular modelling and FTIR have been used to study carboxyl group among acetic acid, potassium and sodium acetate, glycine, sodium salicylate, salicylic acid and cellulose acetate. Molecular modelling was used to study formic acid, carboxylic acids R-COOH, monovalent alkali carboxylate CH₃COO-M. alanine, benzoic acid as well as naphthalene. Each structure was optimized using VWN/DZVP then vibrational spectra were further calculated at the same level of theory. The comparison between both calculated and experimental spectra showed good agreement with each other. Except for formic acid and free carboxyl, the characteristic band is shifted toward lower frequency.

4 illus, 6 tables, 41 ref

011059   Hussain S;Sbaizero O (Dep of Mater Engng and Appl Chem, Univ of Trieste, Trieste-34127, Italy, Email: nuzhtak@citechco.net) : Electrical and microstructural characterization of insulating matrix with conducting particles. Indian J Phys 2005, 52(2), 875-8.

The alumina-Mo system has been chosen as a convenient model system. The conducting phase (Mo) was dispersed in alumina in different amounts (5%, 10%, 20%, 25% in volume). All specimens were fabricated by hot pressing. The bulk conductivities have been measured using two-probe impedance spectroscopy within the available frequency range (5 Hz-13 MHz). The interpretation of the impedance spectra of the system has been discussed together with the brief study of the microstructure.

6 illus, 3 tables, 6 ref

011058   He G;Liu Z J;Luo J H;Kong X Z (Dep of Modern Phys, Lanzhou Univ, Gansu Lanzhou 730000, P R China, Email: kongxz@lzu.edu.cn) : Cross-section measurements of (n, 2n), (n, p) and (n, α) reactions on some selenium isotopes near En=14 MeV. Indian J pure appl Phys 2005, 43(10), 729-32.

Cross-sections for ⁸²Se(n, 2n)^81mSe, ⁸²Se (n, 2n) ⁸¹Se, ⁷⁶Se(n, 2n)⁷⁵Se, ⁷⁸Se(n, p) ⁷⁸As, ⁷⁶Se (n, p)⁷⁶As, ⁷⁴Se(n, p)⁷⁴As and ⁸⁰Se(n, α)⁷⁷Ge reactions have been measured for neutron energies from 13.5 to 14.6 MeV using activation technique. Neutrons were produced by reaction ³H(d, n) ⁴H and neutron flux were monitored by reaction ⁹³Nb (n, 2n) ^92mNb. The results of the present work are compared with the values of previous researchers.

7 illus, 2 tables, 11 ref

011057   Gupta R C;Singh S P (Dep of Electron Engng, Inst of Technol Banaras Hindu Univ, Varanasi- 221 005) : Theoretical modeling of a dielectric-loaded box-horn applicator for hyperthermia treatment of tumors in thorax region. Indian J Radio Space Phys 2005, 34(6), 438-45.

Theoretical analysis of the specific absorption rate (SAR) distribution in three-layered tissue (fat, muscle and lung layers as in thorax region) in direct contact with a box-horn applicator for hyperthermia treatment of cancerous tumor has been presented. The box-horn is assumed to be filled with dielectric (ceramic NPOT-96) to provide a better impedance match to bio-media. The present analysis is based on plane wave spectral technique. The spatial distribution of SAR in fat, muscle and lung layers are computed and reported at 433 and 2450 MHz. Wider SAR-distribution in each of the bio-layers in cross-sectional area and higher penetration depth in lung are observed at 433 MHz in comparison to those at 2450 MHz for dielectric-loaded box-horn. The normalized SAR distributions are also reported for various tissues (fat/muscle/lung layers) at the same depth in order to make a comparative study in these tissues. A modified box-horn, in which the horn is flared in both E- and H-planes is also considered. The effect of substituting pyramidal horn in place of H-plane sectoral horn in the design of box-horn on the SAR distribution is also examined. The results have been validated against available published results in the literature.

7 illus, 1 table, 16 ref

011056   Gunasekaran S;Ponnusamy S (Postgrad and Res Dep of Phys, Pachaiyappa's Coll, Chennai 600 030) : Vibrational spectra and normal coordinate analysis on an organic non-linear optical crystal-3-methoxy-4-hydroxy benzaldehyde. Indian J pure appl Phys 2005, 43(11), 838-43.

The crystal 3-methoxy-4-hydroxy benzaldehyde (vanillin) is a potential non-linear organic crystal. The FTIR and laser Raman spectroscopy have been used to make a qualitative analysis and structural confirmation on vanillin. The molecular structure of vanillin belongs to C3S point group symmetry. A normal coordinate analysis of vanillin has been carried out following Wilson's F-G matrix method using the general quadratic valence force field. A set of orthonormalised symmetry coordinates satisfying the transformation properties is constructed. The validity of the vibrational assignments is supported evaluating the potential constants of the molecule of vanillin. Further, the potential energy distribution has also been evaluated to check, whether the chosen set of vibrational frequencies contribute to the maximum potential energy associated with the normal coordinate of the molecule.

2 illus, 2 tables, 13 ref

011055   Goel P;Yadav K L (Smart Mater Res Lab Dep of Phys, Indian Inst of Technol, Roorkee-247 667, Email: klayfph@iitr.ernet.in) : A comparative analysis of PBZT synthesized by co-precipitation and sol-gel method. Indian J Engng Mater Sci 2005, 12(6), 52-6.

Comparative structural and dielectric analysis of bismuth doped PZT ceramics [Pb_0.98 Bi_0.02 (Zr_0.52 Ti_0.48)O₃] prepared by co-precipitation and sol-gel methods has been done. The thermal and crystallization behaviour of the as prepared powders, structural evolution of the ceramics and dielectric properties of the sintered ceramics have been analyzed and compared. Different stages of phase formation have been observed by X-ray diffractogram (XRD) of the samples calcined at various temperatures. Thermal analysis and XRD both confirm that the temperature as low as 250°C is sufficient to achieve the desired phase in the compounds synthesized by sol-gel method whereas a higher temperature (<126> 500°C) is required to achieve the pure perovskite phase in case of the samples derived by chemical co-precipitation method. Ferroelectric transition temperature (T_c) and ferro-paraelectric phase transition nature remained the same for both of the samples. Hence, the sol-gel prepared material PBZT may be used for silicon based memory device application, where a low synthesis temperature is a major requirement.

8 illus, 15 ref

011054   Gill R;Singh P (NO, DAV Inst of Engng and Technol, Jalandhar, Punjab, Email: rgill12dec@rediffmail.com) : Study of depression of critical temperature of praseodymium doped high T_c cuprates. Indian J pure appl Phys 2005, 43(12), 977-9.

The recent experimental observation of the substitution of praseodymium (Pr) in high transition temperature (T_c)superconducting Y123 compounds gives rise to very interesting properties, such as monotonic decrease of T_c with increase in Pr concentration which is not satisfactorily explained yet. The depression of Tc is due to hole filling/hole localization, magnetic pair breaking or some kind of disorder/dislocation is still not clear. The depression of T_c in Y_1-xPr_x Ba₂Cu₃O_7-x has been explained using magnetic pair breaking, hole filling and disorder. It has been argued that the disorder along with hole filling is responsible for suppression of T_c and subsequently to lower order parameter (Δ).

3 illus, 3 tables, 9 ref

011053   Dubey S;Wahi R;Mingkhwan E;Gwal A K (Space Sci Lab Dep of Phys, Barkatullah Univ, Bhopal-462 026, Email: smitadubey@yahoo.com) : Study of amplitude and phase scintillation at GPS frequency. Indian J Radio Space Phys 2005, 34(6), 402-7.

When a radio wave at L-band frequency passes through the entire ionospheric region, it is affected by the electron density irregularities, which are present in the ionosphere and generate amplitude and phase scintillation of GPS signals. This is especially true during the nighttime. The magnitude of amplitude and phase scintillation and the temporal structure of scintillations need to be specified and predicted to provide support to operational communication and navigation system. Amplitude and phase fluctuation at the GPS frequency at Chiang Rai (19.57°N, 99.52°E), Thailand is described in this paper. It was found that higher amplitude fluctuation level could be observed only in equinox and winter, while S4 is less than 0.4 in summer months.

5 illus, 32 ref

011052   Digpratap S;Sushil K;Singh B P (Dep of Phys, Inst of Basic Sci, Khandari, Agra-282 002, Email: bhanuprakashsingh@yahoo.co.in) : Analysis of inverted type high pressure equations of state for solids. Indian J pure appl Phys 2005, 43(10), 759-64.

Diffrent inverted type equations of state (EOS) have been discussed, which express volume ratio as a function of pressure for materials at a given temperature. It is shown that some of these EOS do not satisfy the basic requirements revealed from the fundamental thermodynamics for solids in the limit of extreme compressions developed by Stacey. The critical test of EOS for solids under extreme compressions by evaluating the pressure-volume derivative properties viz. isothermal bulk modulus and its pressure derivative calculated for MgO and NaCl up to extremely large pressures has been presented. Among the five equations of state studied, the inverted type of EOS due to Bose-Roy S and Bose-Roy P has been found to be most satisfactory. A detailed comparison of this EOS has been presented with the Keane's EOS and the Stacey EOS.

5 illus, 1 table, 26 ref

011051   De S S;Adhikari S K;Debnath A;Das P;B K De (Cent of Advd Study in Radio Phys and Electron, Univ of Calcutta, Kolkata-700 009) : Studies on non-linear heating of the lower ionosphere during interaction between HF and ELF signals. Indian J Radio Space Phys 2005, 34(6), 413-16.

Non-linear interaction between Schumann resonances (SR) and high frequency round-the-world signals (RWS) in the lower ionosphere yields the ELF spectra that correspond to the three first modes of Schumann resonances. The phenomenon resembles Luxembourg effect between Schumann resonances and HF signals. The intensity of natural electromagnetic field (SR field) produced by thunderstorm activity is strong enough to give rise to non-linear effects in the D-layer. As a result, there will be heating of electrons by the ELF oscillations of SR fields (E_s). The fair-weather electric field (E₀) also initiates the process of heating in the D-layer. The influence of this field gives a linear dependence of electron temperature fluctuations on the field strength on SR. These lead to non-linear effects comprising the variations of electron temperature, effective collision frequency and conductivity of the medium. Also, there will be modulation of HF waves by ELF signals.

15 ref

011050   De P (Dep of Phys, Gobardanga Hindu Coll, P O Khantura, 24 PGS(N)-743 273) : Effect of charge bump on the series resistance and microwave properties of Si n<. Indian J pure appl Phys 2005, 43(10), 794-8.

The value of series resistance (R_s) of Si n⁺ np⁺ IMPATT diode has been studied through computer simulation considering experimental bias current and frequency in the X-band, and the results fit well with the device data (1.6 α at 10 GHz) for the flat doping profile. It is further observed that the value of R_s decreases from 1.76 to 0.1128 Ω at 10.7 GHz under experimental current density (3.45 x 10⁶ A.m^-2) and temperature (373K), as the doping profile changes from flat to low-high-low (lhl) type with the incorporation of charge bump. The electric field and the negative resistivity profiles in the depletion layer clearly indicate the advantage of lhl doping profile on the series resistance as well as on its microwave properties. The analysis also gives an idea on the unison of load conductance of the waveguide and negative conductance of the diode at resonance.

5 illus, 2 tables, 20 ref

011049   De B K;Pal M;De S S;Bera R;Adhikari S K;Guha A;Sarkar S K (NO, Tripura Univ, Suryamaninagar-799 130) : Integrated field intensity of ELF-VLF sferics at Tripura, India. Indian J Radio Space Phys 2005, 34(6), 408-12.

The results of observation of the Integrated Field Intensity of Sferics (IFIS) at 0.9, 3, 6, 9 and 12 kHz at Tripura (latitude: 23 °N) are reported here. Some specific characteristics of ELF-VLF atmospherics found from this hilly place are presented, along with a brief description of the experimental set-up for their detection.

9 illus, 1 table, 10 ref

011048   Das T K;Saha A;De B K (NO, Cent for Space Phys, 43, Chalantika, Garia Station Road, Kolkata-700 084, Email: tukada2@vsnl.net) : A preliminary report on LF band signals observed during Sumatra earthquakes. Indian J Phys 2005, 52(2), 905-8.

Electromagnetic emissions during recent earthquakes in the Sumatra region are detected by a LF band receiver placed at Agartala, Tripura University Campus. A preliminary report of these observations is presented.

3 illus, 1 table, 7 ref

011047   Chinna Babu J;Suresh S;Chandra Mouli V (Glassy Mater Res Lab, Dep of Phys, Osmania University, Hyderabad-500 007, Email: vorucm90@yahoo.com) : ESR, IR and optical absorption studies of Cu<. Indian J pure appl Phys 2005, 43(11), 833-7.

ESR, IR and optical absorption studies on xNa₂O-(50-x)ZnO-50B₂O₃ ternary glasses containing Cu²⁺ spin probe have been carried out. The absence of band at 806 cm^-1 in the IR spectra indicates the absence of boroxol rings. Thus, the present glass system consists of borate triangles [BO₃] and borate tetrahedral [BO₄] structural units. It was also observed that structural changes are taking place with variation of Na₂O and ZnO contents. The hyperfine splittings in the parallel features of ESR spectra of Cu²⁺ are recorded for all compositions. ESR results show that the g ?? <62> g ?? indicating that the Cu²⁺ ion is in tetragonal distorted octahedral site and its ground state is d_x²-y². There is considerable variation in g and A values with the increasing concentration of Na₂O, whereas no perceptible changes have been observed in g. and A values. The observed optical absorption peak of Cu²⁺ has been found to be at 800 nm for x = 25 mol% of Na₂O content. Bonding parameters are calculated from both optical and ESR data. All these variations clearly indicate the structural changes in the present glass system with varying Na₂O content.

3 illus, 4 tables, 24 ref

011046   Chickpatil M;Raibagkar R L (Dep of Appl Electron, Gulbarga Univ, Gulbarga-585 106, Email: chickpatil@rediffmail.com) : Effect of M<. Indian J pure appl Phys 2005, 43(11), 869-72.

Polycrystalline samples of Ba(Zn_1/3Nb_1/3Ta_1/3 )O₃ and Ba(Cd_1/3Nb_1/3Ta_1/3)O₃ have been prepared by solid state reaction technique. Preliminary X-ray studies showed the formation of single-phase compound. Zinc doped barium niobium tantalet had a cubic unit cell and cadmium doped barium niobium tantalet had a tetragonal structure. The d-values and intensities for each reflection were computed using the lattice parameters, which agree well with the observed values. The calculated and order line intensities for both compounds decreased in the ordered which is expected from the differences in the atomic scattering factor of B-ions, thus confirms the 1:1 degree of cation ordering.

1 illus, 4 tables, 20 ref

011045   Chakrabarti S K;Nandi A;Debnath D;Sarkar R; Datta B G (NO, S N Bose Natn Cent for Basic Sci, JD-BLOCK, Sector-III, Salt Lake, Kolkata-700 098, Email: chakraba@bose.res.in) : Propagating oscillatory shock model for QPOs in GRO J1655-40 during the March 2005 outburst. Indian J Phys 2005, 52(2), 841-5.

GRO J1655-40, a well known black hole candidate, showed renewed X-ray activity in March 2005 after being dormant for almost eight years. It showed very prominent quasi-periodic oscillations (QPO). The data of two observations , one taken on March 2nd, 2005 and the other taken on the March 11th, 2005. On March 2nd, 2005 have been analysed, the shock was weak and the QPO was seen in roughly all energies. On March 11th, 2005, the power density spectra showed that quasi-periodic oscillations (QPOs) were exhibited in harder X-rays. On the first day, the QPO was seen at 0.13 Hz and on the second day, the QPO was seen at <126> 6.5 Hz with a spectral break at <126> 0.1 Hz. The QPOs for the period 25th February 2005 to 12th of March, 2005 were analysed and it has been shown that the frequency of QPO increased monotonically from 0.088 Hz to 15.01 Hz. This agrees well if the oscillating shock is assumed to propagate with a constant velocity. On several days, author has also noticed the presence of very high frequency QPOs and for the first time, it detected QPOs in the 600 - 700 Hz range, the highest frequency range so far reported for any black hole candidate.

5 illus, 11 ref

011044   Bera P K (Dep of Phys, Dumkal Coll, Basantapur, Dumkal, Murshidabad-742 303, Email: pbera321@sify.com) : Isospectral interactions of the potential V(r)=αr<. Indian J Phys 2005, 52(2), 887-92.

The algebraic methods of supersymmetric, quantum mechanics have been used to construct isospectral potentials for the potential V(r) = αr^2d-2-βr^d-2 in N-dimensional space. It has been shown that the harmonic oscillator and Coulomb problem can be presented in a unified manner. The dimensionality of the problem is seen to enter into these relations in such a way that one can immediately verify the corresponding three-dimensional results as well as the results of Alves and Filho in N-dimension.

17 ref

011043   Arul G;Palaniappan L (Dep of Phys (DDE), Annamalai Univ, Annamalainagar-608 002) : Ultrasonic study of 1-butanol in pyridine with benzene. Indian J pure appl Phys 2005, 43(10), 755-8.

Sound velocity, density and viscosity have been measured in the ternary mixtures of 1-butanol in pyridine with benzene at 303K. Some of the acoustical parameters such as adiabatic compressibility, free length, free volume and internal pressure are calculated from the measured data using the standard relations. The trend shown by the excess parameters of free volume and internal pressure is peculiar that both are negative and in increasing order confirms that the associative nature of alcohol disturbs the molecular symmetry available in benzene molecule. The reduction in the cohesion of dipolar pyridine is also noticed.

4 illus, 2 tables, 17 ref

011042   Anil Kumar;Nagaraja Kumar C (Dep of Phys, Panjab Univ, Chandigarh-160 014, Email: cnkumar@pu.ac.in) : Calculation of Franck-Condon factors and r-centroids using isospectral Hamiltonian approach. Indian J pure appl Phys 2005, 43(10), 738-42.

Calculation of Franck-Condon factors is of interest to study the vibrational transitions in diatomic molecules. Morse potential is one of the commonly used models for these calculations. Using isospectral Harniltonian approach, a family of isospectral potentials, which have the same energy eigenvalues as that of Morse potential has been obtained. The eigenfunctions for this family of isospectral potentials are different from that of the original potential. The Franck-Condon factors and r-centroid values obtained using the deformed wavefunctions can be varied to match the experimental data.

4 illus, 1 table, 15 ref

011041   Anil Kumar (Dep of Phys, Panjab Univ, Chandigarh-160 014) : Information entropy of isospectral Poschl-Teller potential. Indian J pure appl Phys 2005, 43(12), 958-63.

The position and momentum space information entropies of the ground state and first excited state of the Poschl-Teller potential are exactly evaluated. Using isospectral Hamiltonian approach, a family of isospectral potentials, which have the same energy eigenvalues as that of the original potential has been constructed. The information entropy content in the first few levels of the isospectral potential has been calculated and it is shown that the information entropy content in each level can be re-arranged as a function of deformation parameter.

5 illus, 26 ref

011040   Amit Kumar;Prasad K;Choudhary S N;Sinha T P (Mater Res Lab Univ Dep of Phys, T.M. Bhagalpur Univ, Bhagalpur-812 007, Email: k_prasad65@yahoo.co.in) : Phase transition in Pb[(Mg_3/4Cu_1/4)_1/3 Nb_2/3]O₃ ceramic. Indian J Engng Mater Sci 2005, 12(6), 586-90.

Single phase perovskite-type cubic ceramics of Pb[Mg_3/4Cu_1/4)_1/3Nb_2/3]O₃(PMCN) were synthesized by high temperature double step solid state reaction technique. Dielectric studies show relaxor behaviour with diffuse phase transition. The phase transition (T_m) occurs at -22°C at 10 kHz. The frequency dependence of T_m has been modeled using Vogel-Fulcher relation. The dielectric relaxation in PMCN is found analogous to the magnetic relaxation in spin-glass system. The relaxor behaviour in PMCN has also been examined through admittance spectroscopy.

6 illus, 1 table, 28 ref

011039   Alvi P A;Lal K M;Siddiqui M J;Naqvi S A H (Dep of Appl Phys Z H Coll of Engng and Technol, Aligarh Muslim Univ, Aligarh-202 002, Email: parvez_amu@indiatimes.com) : Carbon nanotubes field effect transistors. Indian J pure appl Phys 2005, 43(12), 899-904.

Carbon nanotubes field effect transistors (CNTFETs) are one of the most promising candidates for future nanoelectronics. In this paper, the review of CNTFETs is presented. The structure, operation and the characteristics of carbon nanotubes metal-insulator-semiconductor capacitors have been discussed. The operation and dc characteristics of CNTFETs have been presented.

5 illus, 1 table, 18 ref

011038   Ahmad I;Madani J H;Al-Bar A A (Dep of Phys Fac of Sci, King Abdulaziz Univ, Jeddah, Saudi Arabia, Email: iahmad@kaau.edu.sa) : Proton total reaction cross section for Ca isotopes and the semi-phenomenological nucleon density. Indian J Phys 2005, 52(2), 899-04.

Microscopic study of proton total reaction cross section for Ca isotopes using Gambhir-Patil semi-phenomenological nucleon density has been made within the framework of Coulomb modified Glauber model under the optical limit approximation. It is shown that the semi-phenomenological nucleon density gives a fairly good account of the observed isotopic trends of the reaction cross sections.

3 illus, 1 table, 28 ref

010028   Tiwari A K;Singh A;Tripathi L;Tiwari J; Shrivastava A K (Phys Dep, Government T.R.S. Coll, Rewa (M.P.), Email: tiwarianil_trs@rediffmail.com) : Correlative study of daily variation with solar activity parameters. Ultra Scient phys Sci 2005, 17(1), 1-4.

The annual average values of 1st harmonic amplitudes of high amplitude wave trains for kiel and Halaekala neutron monitor station have been used to see their variation with the annual average magnitude of the sunspot number for the interval 1989-2003. This analysis very clearly supports the earlier finding that the diurnal amplitude are significantly smaller during the low sunspot activity period. Clear cut evidence of significant positive co-relation between the sunspots number and 1st harmonic amplitude has been found. The diurnal phase of daily variation of cosmic rays for the high latitude station kiel as well as for the low latitude station haleakala for the entire period of study has also found co-related with much higher positive co-relation.

4 illus, 5 ref

010027   Shashidhara Prasad J (NO, , Crawford Hall, University of Mysore-570 005) : X-ray crystallography: applications to materials science including bio-molecules. IETE Tech Rev 2005, 22(4), 287-97.

Reviews the X-rays diffraction effects through different crystalline structure of matter. It also describes how X-ray crystallography helps in study of the structure of materials including bio-molecules.

^iia20 illus, 1 table

010026   Rajasekaran G (NO, Inst of Math Sci, Madras-600 113, Email: graj@imsc.res.in) : Hans bethe, the sun and the neutrinos. Resonance 2005, 10(10), 49-66.

Gives an elementary review of recent discoveries in neutrino physics, culminating in the solution of the solar neutrino problem and the discovery of neutrino mass. Atmospheric neutrinos, reactor neutrinos and other important developments are also briefly described.

5 illus, 4 ref

010025   Pusa A (NO, Force and Mass Lab, Raute Precision Oy, Raute-MIKES, PL 22, Fin-15801, Lahti, Finland, Email: aimo.pusa@rauteprecision.fi) : Long-term observation of force transfer transducers as a tool to confirm the measurement capability of force standard machines. MAPAN 2005, 20(3), 231-7.

6 illus, 2 tables

010024   Park Y;Kang D (Div of Phys Metrology, Korea Res Inst of Stand and Sci, P.O. Box 102 Yuseong, Daejeon 305-600, Korea, Email: ykpark@kriss.re.kr) : Build-up force-measuring system and its applications. MAPAN 2005, 20(3), 223-9.

Paper describes various uses of a build-up system. First, it can be used with a large-force standard machine. As an example of a large-force standard using a build-up system, a force standard machine of 10 MN capacity at Korea Research Institute of Standards and Science (KRISS) is described. Second, large-force dissemination, such as the calibration of a high capacity material-testing machine, is described. Finally, as another application of the build-up system, an evaluation method for a deadweight force machine is described.

8 illus, 8 ref

010023   Pandey D;Mishra A;Dave M (NO, Sch of Phys Devi Ahilya Univ, Indore-452 017) : Correlation of Wiener index with X-ray K-absorption parameters of mixed ligand complexes. Ultra Scient phys Sci 2005, 17(1), 9-12.

A new application of Wiener indices in estimating X-ray K-absorption parameters is described. X-ray K-absorption parameters are correlated with Wiener indices. Some mixed ligand complexes of Amino acid are used to establish this type of correlation. The results obtained in the study demonstrate the topological indices of the organic molecules acting as ligands can be used for estimating edge shift theoretically.

1 illus, 1 table, 8 ref

010022   Niehe S (NO, Univ of Appl Sci and Arts, D-30459 Hannover, Germany, Email: stefan.niehe@etech.fh-hannover.de) : Force measuring facility from the range of 1 mN to 10 N. MAPAN 2005, 20(3), 239-48.

In this contribution a force measuring facility for the range from 1 mN to 10 N consisting of a piezoelectric adjustment unit and a precision compensation balance is presented. A metrological characterization of the individual components of the device and results of the examination of force transducers using the force measuring facility are given. Integration of rotary table into the measuring device allows interaction influences between measuring device and force transducer to be taken into account and the measurement deviations to be improved by the factor 8 compared with earlier results.

9 illus, 1 table, 4 ref

010021   Mitra A N (NO, , 244 Tagore Park, Delhi-110 009, Email: ganmitra@nde.vsnl.net.in) : Hans bethe, quantum mechanics, and the lamb shift. Resonance 2005, 10(10), 33-48.

An elementary derivation of the Lamb Shift, as originally given by Hans Bethe, is attempted, with a short historical background on the evolution of QED since the beginning of the last century. The treatment is for a non-relativisitic electron, in keeping with Bethe's proverbial insight into the problem, which renders irrelevant the effect of the electron spin on the problem. The Kramer idea of renormalization is implemented through a simple subtraction of the self-energy of a free electron from that of the electron bound in a hydrogen atom.

12 ref

010020   Ferrero C (NO, Instituto di Metrologia "G. Colonnetti", Strada delle Cacce, 73 Torino-10135, Italy, Email: C.Ferrero@imgc.cnr.it) : Multicomponent force sensors. MAPAN 2005, 20(3), 213-21.

General evaluation is given on the differences between the various dynamometers, by comparing the hyper-volume of the components, which is the locus of the points of the six-dimensional space representing the maximum value of the components, which can be applied to the dynamometer without altering its metrological characteristics. The paper has also considered the main multicomponent calibration systems used and describe the calibration systems realised at the IMGC.

3 illus, 7 tables, 16 ref

010019   Dave M;Mishra A (Sch of Phys, Devi Ahilya Univ, Khandwa Road, Indore-452 017) : Correlation for xanes studies of some copper (II) complexes using randic index. Ultra Scient phys Sci 2005, 17(1), 17-20.

X-ray K-absorption spectra of some copper (II) complexes of newly synthesized mannich bases of biological interest have been studied using Seifert X-ray generator and Cauchois type bent crystal X-ray spectrograph of 0.4m radius. The observed X-ray parameter, e.g. chemical shift, shift of principal absorption maximum, edge-width, effective nuclear charge and percentage covalency have been used to explain the structure of the complexes, and these parameters are sensitive to the topological structure of coordinating legands, so that they can be successfully used for with Randic index.

1 illus, 1 table, 7 ref

008851   Yazar H R;Uluer I (Fac of Art and Sci, Kirikkale Univ, Kirikkale, Turkey, Email: yazar@kku.edu.tr) : A correspondence between IBA-1 and IBA-2 models and electromagnetic transitions in the decay of some erbium isotopes. Pramana J Phys 2005, 65(3), 393-402.

The interacting boson approximation IBA-1 model space, in which neutron and proton degrees of freedom are not distinguished, can be considered as a subspace of the IBA-2 model space. Using the microscopic background of the IBA-2 model, a correspondence can be established between IBA-1 and IBA-2 model space. Since the space of the IBA-1 model can be regarded as a subspace of the IBA-2 model there is a unique way to 'Project' the operators of the IBA-2 model onto those of IBA-1. This projection can be carried out using the F-spin formalism. In the IBA-2 model, the lowest states are indeed fully symmetric, and using the calculations with the help of this projection, explores the energy levels and the electric quadrupole transition probabilities B(E2; I_i → I_f) and gamma-ray E2/M1 mixing ratios for selected transitions of ^{162, 164, .166, 168, 170}Er. Owing to admixtures of non-fully-symmetric states in IBA-2, renormalized the parameters (ε) and (ϕ). This is the first time to show that this projection can be applied to some heavier isotopes and the results obtained for ^{162, 164, 166, 168, 170}Er isotopes are reasonably in good agreement with the previous experimental values.

2 illus, 7 tables, 31 ref