001199   Mali P;Sarkar S K;Das J (Earth Sciences Div, , Department of Science and Technology) : Rain drop size distribution from radar reflectivity measurements. Indian J Radio Space Phys 2003, 32(5), 296-300.

Rain drop size distribution (RDSD) is useful for estimation of attenuation of high frequency electromagnetic waves due to rain. Radar reflectivity (Z) obtained by using an X-band radar operating at ≈9.4 GHz has been used for deducing the results on RDSD at different rain intensities in the range 50-150 mm/hr. The results have been observed to match with the results obtained by other investigators by using distometers for the same range of rain rates. The equation obtained for RDSD is of general type and it would satisfy RDSD for the other rain rates also, if the radar reflectivity (Z) is calibrated properly with various rain rates. The unique feature of this distribution equation has its direct application in radar reflectivity data and rain rate for RDSD.

4 illus, 14 ref

001198   Kumar S;Singh C V (Physics Dep, Agra College, Agra-282 002) : Effects of overtaking disturbances on the motion of cylindrical hydromagnetic shock waves in a rotating gas. Ultra Scient phys Sci 2002, 14(2), 160-71.

Effect of overtaking disturbances behind the flow, on the motion of cylindrical hydromagnetic shock waves in an ideal gas in presence of an axial magnetic field (H₂₀ constant), have been included to improve the accuracy of CCW approach. Assuming an initial density distribution ρ0 = ρ¹r^w, where ρ¹ is the density at the axis of symmetry and w is a constant, the analytical expressions for flow variables have been deduced. Their numerical estimates, only at permissible shock front locations, have been computed and compared with results describing so called Free Propagation.

10 illus, 17 ref

001197   Kajwadkar A P (Applied Physics Dep, Government Engineering College, Jabalpur-482 011) : Analysis of 3-input exclusive NOR gate. Ultra Scient phys Sci 2002, 14(1), 103-6.

A three input Exclusive NOR gate has been discussed and equation for the output from this gate has been derived using Demorgan's theorem. Also the application of the gate has been given.

3 illus, 2 tables, 4 ref

001196   Kailasam M;Thirunavukkarasu A R;Abraham M; Kishore Chandra P;Subburaj R (Central Institute of Brackishwater Aquaculture, , Mahalingapuram main road, Nungambakkam, Chennai-600 034) : Influence of size variation and feeding on cannibalism of Asian sea bass Lates calcarifer (Bloch) during hatchery rearing. Indian J Fish 2002, 49(2), 107-13.

Cannibalism within different size group of sea bass Lates calcarifer fry has been studied under hatchery rearing conditions. The mean cannibalistic percentage was high, when large and small size group (21.8±1.60mm and 11.6±1.02mm, 6.8±0.75 mm and 11.6±1.02mm) were reared in the same container. Higher rate of cannibalism was observed without feed than with feed and increased with duration of rearing. When the same size group fry were reared, rate of cannibalism was significantly low in all the size groups. The results indicated the importance of gradation and frequent feeding for better survival and growth of seabass fry during hatchery rearing.

5 illus, 5 tables, 19 ref

001195   Ghahramany N;Sadeghi M;Forozani G (Physics Dep, Shiraz University, Shiraz 71454 (Iran)) : Form factors determination for proton by using the latest data measured in the energy range of 1.0 to 10.0 GeV. Ultra Scient phys Sci 2002, 14(1), 11-20.

Electric magnetic form factors and then, charge distribution as well as the root-mean square of charge radius of proton have been calculated, by using Rosenbluth approach. In doing so the most recent data for e-p, elastic scattering differential cross section in the energy range of 1 to 10 GeV and momentum transfer squared range of 1 to 5 (GeV/C)²) have been used. While the scaling laws of the form factors remain intact the charge density of proton is a decreasing exponential function of the radius and possesses spherical symmetry.

2 illus, 3 tables, 9 ref

001194   Dwivedy C;Ray S K (Physics Dep, Govt. College, Angul, Orissa) : Temperature dependence of excess molar polarization in the binary mixture of polar-nonpolar liquids. Ultra Scient phys Sci 2002, 14(2), 234-9.

Excess molar polarization in the binary mixture of polar solutes (aniline, pyridine, dimethyl aniline) in non-polar solvents (Benzene, tetrachloromethane) is evaluated at different temperature, i.e. 303.16°K, 305.16K°, 313.16°K and 318.16°K. The nature of variation of the excess molar polarization with the temperature has been studied.

1 table, 10 ref

001193   Chakrabarty D K;Patel S;Vala P;Iyer K N (NO, Centre for Environment and Survey, Vidyanagar Society, 29/251, Ahmedabad - 380 015) : Column density of atmospheric water vapour over Ahmedabadd. Indian J Radio Space Phys 2003, 32(5), 301-5.

Water vapour spectrum has a strong absorption feature around 442.7 nm. Using this property column density of water vapour has been determined at Ahmedabad, a low latitude station. Measurements have been made from 1996 to 2000. Slant column density has been found to be ≈ 10²⁴ cm^-2. The period stretches from a minimum to maximum solar activity. A decreasing trend of water content with an increase of solar activity level is also seen.

6 illus, 16 ref

001192   Aghlara H (Faculty of Physics, University of Tabriz (Iran), ) : Capacitor based on the conducting polyaniline films. Ultra Scient phys Sci 2002, 14(2), 178-85.

Possibility of design and construction of capacitor based on the conducting polyaniline films have been investigated experimentally. Polyaniline (PANI) was prepared in powder form by the chemical method of oxidative polymerization, from which thin films were obtained by solvent evaporating using N-methyl pyrrolidinone (NMP). The purified form of polyaniline was swollen with THF before dispersing in N-methyl pyrrolidinone for film making. The polyaniline films were doped with hydrochloric acid (1.2 N HCl). A number of rectangulaire films having thicknesses of 30 μm and area of 3cm² were prepared. By sandwiching dielectric materials, such as paraffined paper with these layers a number of capacitors were prepared and their different parameters, and stability under both atmospheric and vacuum conditions were investigated. Experimental results show that, by increasing the temperature, capacitance is increased and Q-factor is decreased. Theoretical studies based on permeation rates of dopant in layers and parallel plate capacitor concepts were explored.

5 illus, 15 ref

000124   Lorne Park Research Inc (NO, , Box 101, Suite 2018, 20 Queen Street West, Toronto, Ontario, Canada M5H 3R3) : Apparatus for detecting at least one single or double stranded nucleotide. 0000, (NULL), (NULL).

000123   Council of Scientific & Industrial Research (NO, , Rafi Marg, New Delhi-110 001) : An improved process for the preparation of thin film having transition metal oxide/metal chalcogenides/metal halides coating. 0000, (NULL), (NULL).

000122   Yadav A K;Jha R C;Ray K (University Physics Dep, L.N. Mithila University, Darbhanga-846 004) : Dependence of efficiency on i-layer thickness of amorphous silicon solar cells. Appl Sci Period 2003, 5(3), 131-4.

The Solar Cell absorption efficiency is dependent on its thickness. The Solar Cell conversion efficiency in basically determined by the i-layer. The thicker the i-layer the more efficiency light is absorbed, but a weak electric field appears within the i-layer and it reduces the collection efficiency. Therefore, are has to choose an optimum value for the thickness of i-layer, where maximum conversion efficiency will be obtained. Work has been done on it by taking different widths of i-layer in homojunction p-i-n amorphous, Si-solar Cell. Poisson's equation has been directly used instead of using step-by-step method to obtain current in different parts of the cell. The dependence of short circuit current, I_sc, open circuit current, V_oc and cell efficiency on the variation of i-layer thickness of the cell. The optimum value of the thickness of i-layer, where cell efficiency is found maximum has been determined.

1 illus, 1 table, 5 ref

000121   Singh R;Pandey A N;Tripathi A K;Bansal M K (Bharat Institute of Technology, , By-Pass Road, Meerut-250 103) : Study of valence force constants for tetra-atomic planner and pyramidal molecules using the effective nuclear charge model. Asian J Spectrosc 2002, 6(4), 185-90.

The valence force constants of some trihalides of the elements of groups III-A, VI-A and V-A are evaluated on the basis of the effective nuclear charge model. The computed results are compared with the force constants, which are determined by normal coordinates analysis using latest vibrational wavenumbers. The agreement between the two sets of force constants is reasonably good. It is concluded that the effective nuclear charge model is useful to predict the approximate valuence force constants for the molecules under investigation and complicated molecules.

3 tables, 16 ref

000120   Sherborne J R;Page S E;Flood A;Polson M I J; Gordon K C (Chemistry Dep, University of Otago, P O Box 56, Dunedin, New Zealand) : Resonance Raman spectroelectrochemistry, using a Raman OTTLE cell, of molybdenum tetracarbonyl complexes with polypyridine ligands. Asian J Spectrosc 2002, 6(4), 169-77.

The design of a freeze-pump-thaw optically transparent thin-layer electrode (OTTLE) cell suitable for resonance Raman spectroscopy of electro-active samples has been reported. The cell permits for regorous degassing necessary for dealing with air-sensitive species. The resonance Raman spectra of two such complexes are presented. These are Mo(CO)₄ (dpq) (where dpq is 2,3-di(2-pyridyl)-quinoxaline) and Mo(CO)₄(smdpq) (5mdpq is 5-methyl-2,3-(2-pyridyl)-quinoxaline). The resonance Raman spectra of these complexes differ from the corresponding Re(I) complexes. This is a result of less mixing between the metal dπ and ligand π* MOs in the Mo case. The resonance Raman spectra of the reduced species for Mo(CO)₄ (dpq-) show dpq^-bands close to those observed for [Ru (phen)₂(dpq^-)]⁺ and significantly different from the corresponding Re(CO)₃Cl(dpq^-).

2 illus, 1 table, 28 ref

000119   Sharma Y K;Surana S S L;Gehlot C L;Tandon S P (Physics Dep, Govt P G College, Uttarkashi-249 193) : Optical studies and laser parameters of various Pr<. Indian J Engng Mater Sci 2003, 10(3), 215-8.

Absorption and fluorescence spectra have been studied in the range (400-2400 nm) and (400-800 nm) respectively of twelve glass specimens of Pr³⁺ doped (doping concentration 0.1 and 0.2 mol%) borophosphate, zinc chloride borophosphate, aluminoborophosphate, chlorophosphate, phosphate and borate glass systems. The specimens of glass systems have been prepared by melt quenching technique. Judd-Ofelt parameters (Ω_λ) ealuated using the observed spectral intensities have been used to calculate various laser parameters, viz., spontaneous emission probability (A), radiative life time (τ), fluorescence banching ratio (β) and stimulated emission cross-section (σ_p) for the three different laser transitions ³P_o→³H₄ (485 nm), ³P_o→³H₆ (599 nm) and ³P_o→³F₂ (641 nm). A comparatie study of laser parameters for the various types of glasses shows that aluminoborophosphate (ALBP) glasses are better for the laser transition ³P_o→³H₄ whereas for the laser transitions ³P_o→³H₆ and ³P_o→³F₂, borophosphate (BP) and zinc chloride borophosphate (CLBP) glasses respectively are much better than the other glasses.

1 illus, 3 tables, 26 ref

000118   Risal Singh;Mittal V (Solid State Physics Laboratory, , Delhi-110 054) : Mercury cadmium telluride photoconductive long wave infrared linear array detectors. Def Sci J 2003, 53(3), 281-324.

Mercury cadmium telluride (Hg_{i-x CdxTe)(MCT) photoconductive long wave infrared linear arrays are still in demand due to several advantages. The linear array technology is well established, easier, economical and is quite relevant to thermal imaging even today. The scan thermal imaging systems based on this technology offer wider field of view coverage and capacity for higher resolution in the scan direction relative to staring systems that use expensive and yet to mature focal plane array detector technology. A critical review on photoconductive n-Hg1-xCdxTe linear array detector technology for the long wave infrared range has been presented. The emphasis lies on detector design and processing technology. The critical issues of diffusion and drift effects, Hi-Lo and heterostructure blocking contacts, surface passivation, and other related aspects have been considered from the detector design angle. The device processing technology aspects are of vital importance.}

^iia27 illus, 4 tables, 140 ref

000117   Reddy R R;Nazeer Ahammed Y;Abdul Azeem P;Rama Gopal K;Sasikala Devi B;Rao T V R (Sri Krishnadevaraya University, , Anantapur-515 003) : Dependence of physical parameters of compound semiconductors on refractive index. Def Sci J 2003, 53(3), 239-48.

Interesting relationships have been found between refractive index, plasmon energy, electronic polarisability, bond length, microhardness, bulk modulus, force constants and lattice energy. An attempt has been made for the first time to correlate only one physical parameter with others. The calculated values are in good agreement with the experimental values as well as with the values reported in the literature. Refractive index data is the only one parameter required to estimate all the above parameters.

6 illus, 5 tables, 15 ref

000116   Rao P R (NO, , 7 Saras Baug, Deonar, Mumbai-400 088) : Laser isotope separation of uranium. Curr Sci 2003, 85(5), 615-33.

A rsearch effort was carried out at the Bhabha Atomic Research Centre (BARC), Mumbai, for developing laser-based techniques for enrichment of natural uranium to reactor-grade (2.5% to 3.0% ²³⁵U), with the potential to be economically scalable to industrial production. Three approaches - two molecular, namely CO₂ laser-based approach and UF₆-based approach, and one atomic, namely Atomic Vapour Laser Isotope Separation (AVLIS)-were investigated. The AVLIS method was found to be the best, and was pursued to achieve the goal. In the AVLIS technique, uranium atomic vapour was isotope selectively ionized by three copper vapour laser pumped pulsed dye lasers, and the ions were collected by an electric field. This method could enrich uranium to several times the targetted figure. It is scalable, though some difficult technological problems have to be addressed. The basic scientific aspects of the three approaches and details of the AVLIS technnique are presented.

30 illus, 46 ref

000115   Patel T H;Vaidya R;Patel S G (Phys Dep, Sardar Patel University, Vallabh Vidyanagar-388 120) : Anisotropic behaviour of semiconducting tin monosulphoselenide single crystals. Bull Mater Sci 2003, 26(6), 569-74.

Single crystals of ternary mixed compound of group IV-VI in the form of a series, SnS_xSe_1-x (where x=0, 0.25, 0.50, 0.75 and 1), have been grown using direct vapour transport technique. The grown crystals were characterized by the X-ray diffraction analysis for their structural parameter determination. All the grown crystals were found to be orthorhombic. The microstructure analysis of the grown crystals reveals their layered type growth mechanism. From the Hall effect mesurements Hall mobility, Hall coefficient and carrier concentration were calculated with all crystals showing p-type nature. The d.c. electrical resistivity measurements perpendicular to c-axis (i.e. along the basal plane) in the temperature range 303-453 K were carried out for grown crystals using four-probe method. The d.c. electrical resistivity measurements parallel to c-axis (i.e. perpendicular to basal plane) in the temperature range 303-453 K were carried out for the same crystals. The electrical resistivity measurements showed an anisotropic behaviour of electrical resistivity for the grown crystals. The anisotropic behaviour and the effect of change in stoichiometric proportion of S and Se content on the electrical properties of single crystals of the series, SnS_xSe_1-x (where x=0, 0.25, 0.50, 0.75 and 1), is presented systematically.

3 illus, 4 tables, 39 ref

000114   Mandal M K;Sarkar B C (Radionics Laboratory, Physics Dep, Burdwan University, Golapbag, Burdwan-713 104) : New charge-pump PLL for tracking bursty signals. Indian J Engng Mater Sci 2003, 10(3), 189-92.

A charge pump phase locked loop comprising of a ring oscillator has been proposed to extract continuous carrier signal from burst like input signal. Experimental studies confirm that the simple structural modification provides a fairly steady reconstructed carrier signal.

7 illus, 5 ref

000113   Lingwal V;Semwal B S;Panwar N S (Department of Physics, HNB Garhwal University, Srinagar(Garhwal)-246 174) : Dielectric properties of Na_1-xK_xNbO₃ in orthorhombic phase. Bull Mater Sci 2003, 26(6), 619-25.

Pellets of ceramic, Na_1-xK_xNbO₃(x=0, 0.2 and 0.5), were prepared by conventional solid-state reaction method. Prepared samples were characterized using XRD and SEM. The frequency and temperature variation of dielectric constant, loss tangent and dielectric conductivity of prepared samples were measured in the frequency range from 10 KHz-1 MHz, and in the temperature range from 50-250°C for x=0.2 and 0.5, and between 50 and 480°C for x=0 compositions. It was observed that the dielectric constant and loss tangent decrease, and conductivity increases with increasing frequency. Near the transition temperature the meterial shows anomalous behaviour for the observed properties, and the peaks of dielectric constant and loss tangent were observed shifting towards lower temperature with increasing frequency.

13 illus, 43 ref

000112   Laxmi Kanth C;Appa Rao B;Veeraiah N (Physics Dep, P G College of Science, Osmania University, Saifabad, Hyderabad-500 004) : Influence of modifiers on optical properties of ZnF₂-TeO₂ glass system doped with Eu<. Indian J Engng Mater Sci 2003, 10(3), 207-14.

ZnF₂-MO-TeO₂ (MO = PbO, ZnO and CXdO) glasses doped with Eu³⁺ ions have been pepared ad samples are characterized by X-ray diffraction and differential scanning calorimetric studies. Optical absorption, photoluminescence, infrared spectra and thermoluminescence studies have been carried out; from the measured intensities of various absorption bands of these glasses the Judd-Ofelt parameters Ω₂, Ω₄, amd Ω₆ have been evaluated. The Judd-Oflet theory could successfully be applied to characterise the absorption and luminescence spectra of these glasses. From this theory various radiative properties like transition probability A, branching ratio β_t, the radiative life time τ_R and the emission cross-section σ^E for various emission levels of these glasses have been determined and reported. The analysis of these results with the aid of IR spectra and thermoluminescence studies, it has been identified that CdO mixed tellurite glass as the most favourable host for Eu³⁺ doping and to give high luminescence efficiency.

5 illus, 6 tables, 34 ref

000111   Kharintsev S S;Sevastianov A A;Salakhov M Kh (Physics Faculty, Kazan State University, Kazan-420 008, Russia) : Resolution enhancement of overlapping peaks in molecular spectra by derivative spectrometry method based on continuous wavelet transform. Asian J Spectrosc 2002, 6(4), 145-54.

A numerical differentiation algorithm based on the continuous wavelet transform for improving resolution of composite spectra has been considered. This approach provides the best contrast in differential curves as compared to the conventional derivative spectrometry. A main merit is that the wavelet-based technique gives stable estimations of derivative without using the regularization and on the other hand, it does not make peak shift. A comparative study of conventional derivative spectrometry based on the statistical regularization method and wavelet-based derivative spectrometry is made. Examples of the application of these for improving resolution of synthetic composite bands and real-world composite ones coming from molecular spectroscopy are given.

22 ref

000110   Kharintsev S S;Salakhov M K H (Physics Dep, Kazan State University, Kremlevskaya Str, 16, Kazan 420 008, Russia) : Fractional derivative for finding width, amplitude and shape of overlapping peaks. Asian J Spectrosc 2002, 6(4), 155-67.

A technique based on fractional derivative for finding the overlapping peaks spectral parameters has been described. This is due to positive effects of the fractional derivative caused by the behavior of its zero-crossing and maximal amplitude. A power of the method is demonstrated for synthetic data by using the well-known distributions such as Lorentzian. Gaussian ones and for experimental infra-red spectra coming from molecular spectroscopy. It is shown that recorded spectra are approximated with the Tsallis distribution in the best way, compared to the other distributions.

11 illus, 3 tables, 14 ref

000109   Kalita P K;Sarma B K;Das H L (Department of Physics, Gauhati University, Guwahati-781 014) : Space charge limited conduction in CdSe thin films. Bull Mater Sci 2003, 26(6), 613-7.

The current (I)-voltage (V) characteristics of thermally evaporated CdSe thin films having thickness in the range 850-3000 Angstrom and deposited within the substrate temperature of 303-573 K show nearly linear dependence at low voltage and afterwards a non-linear behaviour at higher voltage range. A detailed study of I-V curves in dark and under illumination clearly reveals the mechanism as ohmic at low voltage and that of trap limited space charge limited conduction (SCLC) at higher voltage. The transition voltage (V_t) from ohmic to SCLC is found to be quite independent of ambient temperature as well as intensity of illumination. SCLC is explained on the basis of the exponential trap distribution in CdSe films. Trap depths estimated from the in I vs 10³/T plots are found to be within 0.60-0.37 eV. Using the relevant SCLC theory, the carrier concentration, _on total trap concentration, N_t, and the ratio of free charge to trapped charge, θ have been calculated and correlated with ambient temperature and intensity of illumination.

5 illus, 2 tables, 21 ref

000108   Deshmukh P T;Burghate D K;Deogaonkar V S; Yawale S P;Pakade S V (Department of Physics, Shri Shivaji Science College, Amravati-444 603) : Optical properties of lead-bismuth cuprous glasses. Bull Mater Sci 2003, 26(6), 639-42.

The optical transmission and absorption spectra in UV-VIS were recorded in the wavelength range 350-800 nm for different glass compositions in the system (CuO)_x(PbO)_50-x(Bi₂O₃)₅₀(x=2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0). Absorption coefficient (α, optical energy gap (E_opt), refractive index (n_D), optical dielectric constant (ε'∞), measure of extent of band tailing (ΔE), constant (β) and ratio of carrier concentration to the effective mass (N/m^*) have been reported. The effects of compositions of glasses on these parameters have been discussed. It has been indicated that a small compositional modification of the glasses lead to an important change in all the optical properties including non-linear behaviour. The optical parameters were found to be almost the same for different glasses in the same family.

4 illus, 1 table, 12 ref

000107   Chavan N V;Motke S G;Khedkar C D (NO, Adarsha Education Society's College, Hingoli-431 513) : Study of oxygen interaction with LaB₆ using auger electron spectroscopy. Appl Sci Period 2003, 5(3), 139-47.

Interaction of cataphoretically deposited LaB₆ with oxygen has been carried out. Adsorption of oxygen and oxidation at elevated temperatures is studied. The variation in surface concentration of lanthanum, boron and oxygen at various oxygen exposures is determined by Auger electron spectroscopy technique. Lanthanum percentage is found to increase slowly at higher oxygen exposure. Masking of boron atoms by oxygen atoms is obsered. At elevated temperature faster oxidation is observed.

9 illus, 1 table, 5 ref

000106   Akman I;Bayrak A B;Bayrakceken F (Yeditepe University, Electronics Engineering Dep, , Istanbul-81120, Turkey) : In Vitro, spectroscopic study of the retinal cells of the anatolian honey bee. Asian J Spectrosc 2002, 6(4), 179-84.

Anatolian honey bees are active in bright sun light, sunlight, shade, twilight and dark. They rely for their survival on vision and perceive the world through many-faceted compound eyes. The compound eyes work as an optical sampling device and is made up of the little eyes. Light absorbed by the retinal cells transmits a signal to the honey bee's brain through an optical lobe. Anatolian honey bees can see the optical band 350-750 nm and can recognise the difference between the polarized and unpolarized lights. The visual field extends through 246° in the horizontal plane and 360° in a vertical plane, the fields of two eyes overlapping so as to give binocular vision in front, above and below the head.

5 illus, 25 ref

017583   Tripathi R;Kumar A;Sinha T P (Physics Dep, Government Post Graduate College, Rishikesh-249 201, Email: drakhilesh26@gmail.com) : Dielectric properties of CdS nanoparticles synthesized by soft chemical route. Pramana J Phys 2009, 72(6), 969-78.

CdS nanoparticles have been synthesized by a chemical reaction route using thiophenol as a capping agent. The frequency-dependent dielectric dispersion of cadmium sulphide (CdS) is investigated in the temperature range of 303-413 K and in a frequency range of 50 Hz-1 MHz by impedance spectroscopy. An analysis of the complex permittivity (ε' and ε") and loss tangent (tan 5) with frequency is performed by assuming a distribution of relaxation times. The scaling behaviour of dielectric loss spectra suggests that the relaxation describes the same mechanism at various temperatures. The frequency-dependent electrical data are analysed in the framework of conductivity and modulus formalisms. The frequency-dependent conductivity spectra obey the power law.

7 illus, 15 ref

017582   Thakor P B;Gajjar P N;Jani A R (Physics Dep, Veer Narmad South Gujarat Univ, Surat-395 007, Email: pbthakor@rediffmail.com) : Phonon dispersion relation of liquid metals. Pramana J Phys 2009, 72(6), 1045-9.

The phonon dispersion curves of some liquid metals, viz. Na (Z = 1), Mg (Z = 2), Al (Z = 3) and Pb (Z = 4), have been computed using the model potential. The charged hard sphere (CHS) reference system is applied to describe the structural information. The model potential along with CHS reference system is capable of explaining the phonon dispersion relation for monovalent, divalent, trivalent and tetravalent liquid metals.

1 illus, 1 table, 15 ref

017581   Singh S C;Swarnkar R K;Gopal R (Physics Dep, University of Allahabad-211 002, , Email: Subhash_laserlab@yahoo.co.in) : Zn/ZnO core/shell nanoparticles synthesized by laser ablation in aqueous environment: optical and structural characterizations. Bull Mater Sci 2010, 33(1), 21-6.

Zn/ZnO core/shell nanoparticles are synthesized by pulsed laser ablation (PLA) of Zn metal plate in the aqueous environment of sodium dodacyl sulfate (SDS). Solution of nanoparticles is found stable in the colloidal form for a long time, and is characterized by UV-visible absorption, transmission electron microscopy (TEM), photoluminescence (PL) and Raman spectroscopic techniques. UV-visible absorption spectrum has four peaks at 231, 275, 356, and 520 nm, which provides primary information about the synthesis of core-shell and elongated nanoparticles. TEM micrographs reveal that synthesized nanoparticles are monodispersed with three different average sizes and size distributions. Colloidal solution of nanoparticles has significant absorption in the green region, therefore, it absorbs 514.7 nm light of Ar⁺ laser and emits in the blue region centred at 350 and 375 nm, violet at 457 nm and green at 550 nm regions. Raman shift is observed at 300 cm^-1 with PL spectrum, which corresponds to ³E_2N and E_3L mode of vibrations of ZnO shell layer. Synthesis mechanism of Zn/ZnO core/shell nanoparticles is discussed.

6 illus, 27 ref

017580   Saha S;Bhaumik S;Roy A (Physics Dep, Indian Institute of Technology, Kharagpur-721 302, Email: anushree@phy.iitkgp.ernet.in) : Coupling between drainage and coarsening in wet foam. Pramana J Phys 2009, 72(6), 1037-44.

Drainage and coarsening are two coupled phenomena during the evolution of wet foam. We show the variation in the growth rate of bubble size, along the height in a column of Gillette shaving foam, by microscope imaging. Simultaneously, the drainage of liquid at the same heights has been investigated by Raman spectroscopic measurements. The observations made in these two sets of experiments indicate the coupling between drainage and coarsening in wet foam. We could explain the correlation between our observed data on drainage and coarsening by the empirical relation, proposed by others, in the literature.

6 illus, 15 ref

017579   Ravichandran V;Jeyakumari S;Chinnathambi V; Rajasekar S;Sanjuan M A F (Physics Dep, Sri K.G.S. Arts College, Srivaikuntam-628 619) : Role of Asymmetries in the chaotic dynamics of the duble-well Duffing oscillator. Pramana J Phys 2009, 72(6), 927-37.

Duffing oscillator driven by a periodic force with three different forms of asymmetrical double-well potentials is considered. Three forms of asymmetry are introduced by varying the depth of the left-well alone, location of the minimum of the left-well alone and above both the potentials. Applying the Melnikov method, the threshold condition for the occurrence of horseshoe chaos is obtained. The parameter space has regions where transverse intersections of stable and unstable parts of left-well homoclinic orbits alone and right-well orbits alone occur which are not found in the symmetrical system. The analytical predictions are verified by numerical simulation. For a certain range of values of the control parameters there is no attractor in the left-well or in the right-well.

7 illus, 27 ref

017578   Rapapa N P;Fabiane M (NO, The Abdus Salam International Centre for Theoretical Physics, P.O. Box 586, Strada Costiera 11, Trieste, Italy, Email: np.rapapa@nul.ls) : Corrections to scaling within Mazenko's theory in the limit of low and high dimensions. Pramana J Phys 2009, 72(6), 979-88.

Considers corrections to scaling within an approximate theory developed by Mazenko for nonconserved order parameter in the limit of low (d → 1) and high (d → ∞) dimensions. The corrections to scaling considered here follows from the departures of the initial condition from the scaling morphology. Including corrections to scaling, the equal time correlation function has the form: C(r,t) = fo(r/L)+L^ω f₁(r/L) + ..., where L is a characteristic length scale (i.e. domain size). The correction-to-scaling exponent ω and the correction-to-scaling functions f₁(x) are calculated for both low and high dimensions. In both dimensions the value of ω is found to be ω = 4 similar to 1D Glauber model and OJK theory (the theory developed by Ohta, Jasnow and Kawasaki).

3 illus, 15 ref

017577   Rana J M S (Physics Dep, J.N.B. Garhwal Univ, S.R.T. Campus, Badshahithaul (Tehri-Garhwal), Uttarakhand, Email: ranajms@gmail.com) : Implications of duality, confinement and supersymmetry in restricted quantum chromodynamics (RCD). Panjab Univ Res J Sci 2009, 59(1-4), 183-212.

Duality has been utilized to study the bulk QCD magnetic properties, particularly isocolor chargc-dyon interactions in Restricted Quantum Chromodynamics (RCD). In the state of dyonic superconductivity, it has been shown that the dual propagators behave as 1/k⁴ (for small k ) which leads to the confinement of colored fluxes associated with dyonic quarks vide generalized Meissner effect. Based on semi-quantitative analysis of vortex solutions of RCD, it has been demonstrated that in the type I superconducting medium, vortices tend to coalesce and hence are attractive, while the energy function supports repulsive forces between vortices in type II medium. Furthermore, incorporating the dyonic color charge and color spin induced as a result of fermion fractionization in Georgi-Glashow model, in presence of an isovector fermion field, into the N=1 supersymmetric RCD, the Lagrangian density has been constructed and supersymmetric dyonic solutions have been obtained. It has been shown that the bosonic and fermionic fluctuations exactly cancel each other and thus one-loop quantum corrections lead no change in classical mass of dyon.

39 ref

017576   Raghavender M;Kumar G S;Prasad G (Physics Dep, Materials Research Laboratory, Osmania Univ, Hyderabad-500 007) : A-site substitution-controlled dielectric dispersion in lead-free sodium bismuth titanate. Pramana J Phys 2009, 72(6), 999-1009.

Effect of doping in Na_0.5Bi_0.5TiO₃ (NET) with Ce³⁺ and Sm³⁺ at the A-site on dielectric behaviour, impedance and conductivity is being reported. Na_0.5Bi_0.5TiO₃ samples (A being Ce and Sm) are studied with varying values of x. For Na_0.5Bi_0.5-xCe_xTiO₃ samples x is 0.001, 0.005 and 0.007 and for Na_0.5Bi_0.5-xSm_xTiO₃ samples x is 0.05, 0.1 and 0.15. Dielectric constant and loss are studied in the frequency range 10 kHz to 1 MHz and in the temperature range 30-650°C. Impedance and electric modulus studies are undertaken. The relaxations observed in the samples are non-Debye and activation energies for relaxation and conduction are evaluated.

5 illus, 2 tables, 19 ref

017575   Palaniswamy S;Balasundaram O N (Physics Dep, PSG College of Arts & Science, Coimbatore-641 014) : Growth and characterization of glycine sodium nitrate as laser based non-linear optical material. Asian J Chem 2009, 21(5), 3459-62.

Single crystals of glycine sodium nitrate (GSN), a semi organic non-linear optical material has been grown from solution by slow evaporation at ambient temperature. The growth of crystals has been observed at various pH values. The chemical composition of the grown crystals was determined by FTIR spectra. The crystalline nature and its various planes of reflection were observed by powder XRD. The second harmonic generation was also confirmed using Nd:YAG laser.

2 illus, 2 tables, 6 ref

017574   Pal D;Golam Ali S;Talukdar B (Physics Dep, Visva-Bharati Univ, Santiniketan-731 235, Email: binoy123@bsnl.in) : Evolution of optical pulses in the presence of third-order dispersion. Pramana J Phys 2009, 72(6), 939-50.

Proposes a model be the propagation of femtosecond pulses through optical fibres by a nonlinear Schrodinger (NLS) equation involving a perturbing term arising due to third-order dispersion in the medium. The perturbative effect of this higher-order dispersion causes the usual NLS soliton to emit a radiation field. As a result, the given initial pulse propagating through the fibre exhibits nonsolitonic behaviour. Makees use of a variational method to demonstrate how an initial pulse by the interaction with the emitted radiation can evolve into a soliton. Also demonstrate that the effect of interaction between the initial pulse and radiation field can be accounted for by including, in the evolution equation, terms associated with self-steepening and stimulated Raman scattering that characterize the optical medium.

1 illus, 14 ref

017573   Mojumdar S C;et al. (Engineering Dep, New Brunswick Univ, Saint Johan, NB, Canada E2L 4L5, Canada, Email: mojumdar@unbsj.ca) : Introduciton to thermodynamic modeling, thermal analysis and calorimetry. Res J Chem Envir 2009, 13(4), 86-103.

Thermodynamic modelling is a powerful tool for predicting and understanding the behaviour of various systems. There are many thermoanalytical techniques such as thermogravimetric analysis (TGA), high resolution thermo gravimetric analysis (Hi-ResT TGA), derivative thermogravimetry (DTG), differential thermal analysis (DTA), calorimetry, differential scanning calorimetry (DSC), modulated differential scanning calorimetry (MDSC), dynamic mechnical analysis (DMA), thermomechanical analysis (TMA), thermodilatometry (TD), dielectric thermal analysis (DEA), optical transmittance thermal analysis (OTTA), evolved gas analysis (EGA), μ-thermal analysis (μTA), isothermal pressure transducer analysis (ITPTA), transient thermal analysis (TTA) and thermal conductivity (k). Simultaneous thermal analysis (STA) is ideal for investigating issues such as the glass transition of modified glasses, binder burnout, dehydration of ceramic materials or decomposition behaviour of inorganic building materials, also with gas analysis. Thermodynamic modeling and various thermoanalytical techniques and their applications from medicine to construction have been discussed.

10 illus, 155 ref

017572   Madani M (Radiation Physics Dep, National Centre for Radiation Research and Technology, Nasr City, Cairo, Egypt, Email: madany_2000@yahoo.com) : Structure, optical and thermal decomposition characters of LDPE graft copolymers synthesized by gamma irradiation. Bull Mater Sci 2010, 33(1), 65-73.

Methyl methacrylate (MMA) monomer was grafted onto low density polyethylene by the direct method of radiation grafting. The effect of cohesive energy density of different organic solvents on the degree of grafting was investigated. It was found that the extent of grafting depends largely on the kind of solvent, in which the highest degree of grafting was achieved in the presence of dioxane, whereas the lowest degree of grafting occurred in the presence of methanol. This behaviour was attributed to the solubility parameters of the solvent, monomer and polymer. The change in structure of the LDPE graft copolymer films was characterized by scanning electron microscopy, X-ray diffraction, UV/vis absorption and thermogravimetric analysis. The X-ray diffraction results showed a decrease in the crystallinity of LDPE graft copolymer matrix at high degree of grafting. Studies were made on the UV-absorption edge, and indirect allowed transitions with their optical energy gaps are determined. At the same time the Urbach energy was evaluated. The activation energy of the thermal decomposition was calculated according to Horowitz and Metzger method.

8 illus, 4 tables, 37 ref

017571   Li H;Zhang J (College of Science, Zhongyuan Technology Univ, Zhengzhou-450 007, Email: zhangjin6602@sohu.com) : The auxiliary elliptic-like equation and the exp-function method. Pramana J Phys 2009, 72(6), 915-25.

The auxiliary equation method is very useful for finding the exact solutions of the nonlinear evolution equations. In this paper, a new idea of finding the exact solutions of the nonlinear evolution equations is introduced. The idea is that the exact solutions of the auxiliary elliptic-like equation are derived using exp-function method, and then the exact solutions of the nonlinear evolution equations are derived with the aid of auxiliary elliptic-like equation. As examples, the RKL models, the high-order nonlinear Schrodinger equation, the Hamilton amplitude equation, the generalized Hirota-Satsuma coupled KdV system and the generalized ZK-BBM equation are investigated and the exact solutions are presented using this method.

20 ref

017570   Kheraj V A;Panchal C J;Desai M S;Potbhare V (Applied Physics Dep, Faculty of Technology & Engineering, M.S. Baroda Univ, Vadodara-390 001, Email: cjpanchal_musu@yahoo.com) : Simulation of reflectivity spectrum for non-absorbing multilayer optical thin films. Pramana J Phys 2009, 72(6), 1011-22.

Reflectivity simulation is an essential tool for the design and optimization of optical thin films. We have developed a reflectivity simulator for non-absorbing dielectric multilayer optical thin films using Lab VIEW. The name of the substrate material as well as the material and thickness of each layer of the multilayer stack are fed into the program as input parameters in a pop-up window. The program calculates reflectivity spectrum for the given range of wavelengths using layer thicknesses and dispersion data of refractive indices for the defined stack of dielectric materials. The simulated reflectivity spectra for various combinations of materials in multilayer stacks are presented and compared with the experimental results of the multilayer optical thin films grown by electron-beam evaporation technique.

8 illus 12 ref

017569   Ketabi S A;Fouladi A A (Physics School, Damghan Basic Science Univ, Damghan, Iran, Email: saketabi@dubs.ac.ir) : Transport properties of poly (GACT)-poly(CTGA) deoxyribonucleic acid: a ladder model approach. Pramana J Phys 2009, 72(6), 1023-36.

Based on the tight-binding Hamiltonian model and within the framework of a generalized Green's function technique, the electronic conduction through the poly(GACT)-poly(CTGA) DNA molecule in SWNT/DNA/SWNT structure has been numerically investigated. In a ladder model, we consider DNA as a planar molecule containing M cells and four further sites (two base pair sites and two backbone sites) in each cell, sandwiched between two semi-infinite single-walled carbon nanotubes (SWNT) as the electrodes. Having relied on Landauer formalism, we focussed on studying the current-voltage characteristics of DNA, the effect of the coupling strength of SWNT/DNA interface and the role of tube radius of nanotube contacts on the electronic transmission through the foregoing structure. Finally, a characteristic time was calculated for the electron transmission, which measures the delay caused by the tunnelling through the SWNT/DNA interface. The results clearly show that the calculated characteristic time and also the conductance of the system are sensitive to the coupling strength between DNA molecule and nanotube contacts.

6 illus, 1 table, 42 ref

017568   Hu Y X;Wu S Y;Wang S F;Li L L (Applied Physics Dep, Electronic Science & Technology of China Univ, Chengdu-610 054, Email: wushaoyi@netease.com) : g Factors and the superhyperfine parameters for Ni<. Pramana J Phys 2009, 72(6), 989-97.

The g factors and the ligand superhyperfine parameters A' and B' for Ni³⁺ in KMgF₃, CsCaF₃ and RbCaF₃ are theoretically studied from the formulas of these parameters for a 3d ion under octahedral environments in the weak field scheme. The unpaired spin densities for the fluorine 2s, 2pσ and 2pπ orbitals are quantitatively de-termined from the molecular orbital and configuration interaction coefficients based on the cluster approach. The calculated results show good agreement with the experimental data, based on only one adjustable parameter (i.e., the proportionality factor ρ related to the ligand s- and p-orbitals). The superhyperfine parameters for the axial and planar ligands in RbCaF₃:Ni³⁺ are satisfactorily interpreted from the different impurity-ligand distances due to the elongation of the ligand octahedron during cubic-to-tetragonal phase transition.

2 tables, 35 ref

017567   Anusionwu B C;Madu C A;Orji C E (Physics Dep, Federal Technology Univ, Owerri, Nigeria, Email: abedec@yahoo.com) : Theoretical studies of mutual diffusivities and surface properties in Cd-Ga liquid alloys. Pramana J Phys 2009, 72(6), 951-67.

The mutual diffusion coefficients, activation energy for diffusion, surface concentration and surface tension of the liquid Cd-Ga alloys have been calculated throughout the concentration range using energetics obtained from the theoretical model fits of the experimental thermodynamic data. The calculations show that Cd-Ga liquid alloys showed immiscibility at a temperature of 723 K between 0.4 and 0.5 atomic fraction of Cd. Within this concentration region and temperature, the mutual diffusion coefficients approached zero values and the activation energy for diffusion reached high peak values of 220 J/mol. It was also observed that within the region of immscibility, the diffusion coefficients do not obey Arrhenius relation over a wide range of temperature.

10 illus, 3 tables, 26 ref

016424   Suriyamurthy N;Panigrahi B S (Radiological Safety Div, Indira Gandhi Centre for Atomic Research, Kalpakkam-603 102, Email: bsp@igcar.gov.in) : Luminescence studies during combustion synthesis of a long afterglow phosphor Sr₄Al₁₄O₂₅:Eu<. Indian J Engng Mater Sci 2009, 16(3), 178-80.

The long glow persistent phosphor Sr₄Al₁₄O₂₅:Eu²⁺, Dy³⁺ has been synthesized through combustion route. SrAl₄O₇ and SrAl₂O₄ are identified as the intermediate products formed at different temperatures during the synthesis of Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺. The photoluminescence and afterglow emission of the intermediate products have been systematically studied. The photoluminescence and afterglow emission profiles of the intermediate products varied with the temperature of synthesis. For a sample with similar aluminate phases (at a particular synthesis temperature) the λ_AGL and λ_PLXPL are different. However, for Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ annealed at 1200-1300°C, the AGL and PL emissions are similar.

3 illus, 6 ref

016423   Sudheendran K;Raju James K C (School of Physics, Hyderabad Univ, Hyderabad-500 046, Email: kejrsp@uohyd.ernet.in ) : Temperature dependent impedance and dielectric properties of 0.7 CaTiO3-0.3 NdA1O3 ceramics. Indian J Engng Mater Sci 2008, 15(2), 133-6.

Dielectric and impedance spectroscopic studies carried out on a 0.7CaTiO_3- 0.3NdAlO₃ composition have been reported. The material is synthesized by the conventional ceramic method and the dielectric measurements are carried out as a function of frequency (1 kHz-4.5 MHz) in the temperature range of 150-303 K. The impedance measurement is carried out at different temperatures to separate the grain and grain boundary contributions. The grain boundary resistance is evaluated from the measured Z-Z" plots. Both of them are found to be decreasing with the increase in temperature.

7 illus, 8 ref

016422   Singh D;Singh L R (Physics Dep, Manipur Univ, Canchipur, Imphal-795 003, Email: dorendrajiit@yahoo.co.in) : Preparation of Eu<. Indian J Engng Mater Sci 2009, 16(3), 175-7.

Nanocrystalline of Y₄O₃ doped with Eu³⁺ at different concentrations and also core-shell of Y₄O₃ is prepared by wet chemical method using urea hydrolysis at low temperatures. XRD, TEM and FTIR are used to characterize the prepared nanoparticles. The sizes determined by XRD are well in agreement with TEM results. As-prepared samples show luminescence peak of Eu³⁺ transition ⁵D₀ → ⁷F₂ at 615 nm but annealed samples at 610 nm. Core-shell study of the nanoparticles show reduction in the luminescence intensity compared to the core particles.

4 illus, 9 ref

016421   Sharma S;Pitale S;Malik M M;Dubey R N;Qureshi M S;Vasisth S K;Pathak P (Physics Dep, Maulana Azad national Institute of Technology (MANIT), Bhopal-462 051, Email: suchindersharma@yahoo.co.in) : Synthesis and thermoluminescence studies of Sr₄Al₁₄O₂₅:Eu<. Indian J Engng Mater Sci 2009, 16(3), 165-8.

Trapping parameter, the activation energy (E), the order of kinetics (6) and the frequency factor (s), are determined for the solution combustion synthesized Sr₄Al₁₄O₂₅: Eu²⁺ phosphor using ⁶⁰Co irradiation source. The glow curve is a double peak structure with prominent peak at 487 K with shoulder at 423 K. Non-shifting T_m property is utilized for the trap parameter determination. Glow curve deconvolution (GCD) is carried out on recorded glow curves after gamma radiations. The trap depths calculated ranges between 0.5-1.36 eV. The linearity characteristic of the present phosphor and the fading experiments suggests the aptness of present phosphor towards dosimetric applications.

4 illus, 5 ref

016420   Pradhan D K;Choudhary R N P;Tirado C M; Katiyar R S (Physics Dep, Puerto Rico Univ, San Juan, PR00931, USA) : Effect of La/Mn substitution on electrical properties of BifeO₃ multiferroics. Indian J Engng Mater Sci 2008, 15(2), 87-90.

The polycrystalline fine powder (<126>60 nm) of Bi_0.90La_0.10(Fei_1-xMn_x)O₃ (x= 0, 0.05, 0.10 and 0.20) have been synthesized by mechanical activation and mixed oxide methods. Preliminary structural analysis using X-ray diffraction exhibits formation of the single-phase compound in a hexagonal (distorted perovskites system). Detailed dielectric studies as a function of temperature show that dielectric constant of BFO (BiFeO₃), and also tanδ increase significantly on increasing Mn content in BiLa(FeMn)O₃ system. Impedance analysis of the system provides many interesting results.

12 ref

016419   Parmar M C;Zhuang W D;Murthy K V R;Huang X W; Hu Y S;Natarajan V (National Engineering Research Centre for Rare Earth Materials, General Research Institute for Nonferrous Metals & Grirem Advanced Co., Beijing, 100088, China) : Role of SiO₂ in Zn₂SiO₄:Mn<. Indian J Engng Mater Sci 2009, 16(3), 185-7.

Zn_2-xMn_xSiO₄ is a classical green phosphor, and it has been used in many applications, such as CCFL, CRT, PDF etc. In this paper, Zn₂SiO₄:Mn²⁺ green phosphor is fabricated with the solid-state reaction method. Photoluminescence and crystalline properties are examined as functions of the firing temperatures. Zn_2-xMn_xSiO₄ is ground and fired at 1200°C for 4 h in air, but intensity of emission is weak. Therefore, the conditions of firing are changed and Zn_2-xMn_xSiO₄ are ground and fired at 1000°C for 2 h in air and again ground and fired at 1200°C for 4 h in air respectively. When varies SiO₂ value from 0.9 to 1.8 however the ZnO is 1.92 as well as MnCO₃ is 0.08 are constant, The SiO₂ concentration (1.1) show good PL spectra. The PL peak observed at 524 nm in these phosphors suggests their potential as green emitting phosphors under 254 nm excitation.

4 illus, 20 ref