014354   Verma P L;Nigam S K;Tiwari R N;Tiwari D P (Physics Dep, Government P.G. College, Maihar, Satna, Madhya Pradesh) : Role of the interplanetary shocks in producing forbush decreases og higher magnitudes. Acta Cienc Indica-Phys 2004, 30(3), 329-31.

Forbush decreases of different magnitude and their percentage association with interplanetary shocks for the period 1977-2000 have been studied. It has been found that near about all the Fds having magnitudes ≥ 7% are caused by interplanetary shocks.

1 illus, 1 table, 14 ref

014353   Verma P L;Nigam S K;Tiwari R N (Phys Dep, Govt. Vivekanand College, Maihar, Satna, M.P) : Coronal mass ejection, interplanetary shocks and forbush decreases. Acta Cienc Indica-Phys 2004, 30(4), 457-9.

Coronal mass ejection (CMEs) are now widely recognized as being possible for transient interplanetary shocks and hence for most Geomagnetic storms, for the production of energetic particle events, and for Forbush decreases in the cosmic ray radiation. In the paper authors have associated Forbush decreases ≥ 4% obtained from Neutron Monitor Data for the period (1974 to 2000) with Coronal Mass Ejections and Interplanetary shocks that they generate. It was found that maximum number of Forbush decrease (Fd) events are associated with Coronal Mass Ejection and Interplanetary shocks. This investigation indicates that the Fds events and shocks are caused by Coronal Mass Ejection (CME).

11 ref

014352   Verma A S (Physics Dep, Govt. P.G. College, Guna-473 001) : Noise in single injection solid state diode m with thermal free carriers at high fields. Acta Cienc Indica-Phys 2004, 30(3), 289-92.

Analytical expressions for the thermal noise in the single injection solid state diode with thermal free carriers operating in the high field regime has been derive with the help of regional approximation method. It is shown that the noise is strongly dependent on the injection level of current.

1 illus, 6 ref

014351   Urvesh Kumar;Saxena S (Phys Dep, Bareilly College, Bareilly-243 001) : Polarization of <. Acta Cienc Indica-Phys 2004, 30(4), 397-400.

The study of polarization of M³He provides an important information about the chemical structure of material. In particular, the development of high power lasers has enabled the realization of dense, highly polarized samples of ³He. Developed a method to polarize ³He nuclei using spin exchange with optically pumped rubidium atoms. The population density and relative absorption cross-sections are computed. The variation of cross-section with pressure is also observed.

2 illus, 6 ref

014350   Upadhyay P N;Shyam Nandan (Physics Dep, Nalanda Mahila College, Biharsharif, Nalanda-803 101) : Results on the charmed D<. Acta Cienc Indica-Phys 2004, 30(3), 285-8.

An account of results obtained by photo production data for the charmed D⁰ → K^-π⁺ decay mode has been presented. A pronounced peak for the charmed D⁰ mesons has appeared near it mass 1865 MeV. This result is in agreement with those of others.

3 illus, 5 ref

014349   Upadhyay P N;Nandan S;Upadhyay S N (Physics Dep, Nalanda Mahila College, Biharsharif-803 101) : Kinematic calculations for the production of a meson in the π<. Acta Cienc Indica-Phys 2004, 30(3), 241-4.

Presented here are some interesting results obtained by calculating some Kinematic parameters involved in a missing mass spectrometer. It was employed to estimate the missing mass of a meson produced in the π^- p intraction near its production threshold.

2 illus, 7 ref

014348   Sinha K P;Singh T A N;Singh S N;Mishra L K (Phys Dep, Magadh University, Bodh-Gaya-824 234) : An evaluation of total self energy for a moving charge as a function of distance for the metal insulator interface. Acta Cienc Indica-Phys 2004, 30(4), 443-9.

Authors have evaluated the real part of the self energy of a moving charge near a metal insulator interface like Al-LiF, Al-KCl and Al-NaCl. Authors have taken the polarization interaction due to plasmons, Optical phonon and excitons. Result indicates that the real part of self energy as a function of z-decreases for z <60> 0 and increases for z <62> 0.

3 tables, 20 ref

014347   Sinha K P;Singh T A N;Singh S N;Mishra L K (Phys Dep, Magadh University, Bodh-Gaya-824 234) : An evaluation of self energy of an electron in a gap between two metal and near a metallic slab. Acta Cienc Indica-Phys 2004, 30(4), 391-96.

Using the formalism of Manson and Ritchie evaluated the self energy of an electron located in the gap betwen two similar metals and near a metallic slab. Results indicate that the self energy of an eldectron (Σ(0)) increases as a fraction of distance d for r_s=2 to 6. The self energy of an electron located at the surface of metallic slab Σ(a) also decreases with distance d.

3 tables, 20 ref

014346   Sinha K P;Singh T A N;Singh S N;Mishra L K (Phys Dep, Magadh University, Bodh-Gaya-824 234) : An evaluation of total self energy for a static charge as a function of distance for the insulator-vacuum surface. Acta Cienc Indica-Phys 2004, 30(4), 383-90.

Authors have estimated the total self energy for a static charge of mass m=1 near an insulator vacuum surface. The contribution to the total self energy comes from exciton and optical phonon contribution. Authors have shown that the contribution to the exciton field for a distance close to the surface dominates over the optical phonons.

3 tables, 20 ref

014345   Singh S N;Singh V K (Phys Dep, C.M.Sc College, Darbhanga, Bihar) : Study of characteristic behaviours of bow-tie antenna as transmission line. Acta Cienc Indica-Phys 2004, 30(4), 451-55.

A Transmission line analysis of bow-tie antenna is presented. This structure belongs to the class of conical transmission lines. TE and TM eigenmode analysis is particularised to thebow-tie structure. Bow-tie antenna and LTSA are shown to be dual conical transmission lines. The mades of LTSA are calculated on the basis of results obtained for the bow-tie structure. The radiation pattern of LTSA is computed as integral of a closed from expression of the dyadic Green's function. The obtained dominant mode radiation pattern are validated by measurements from the literature.

5 illus, 8 ref

014344   Singh S N;Sharma B A;Gartia R K (Luminescence Dating Laboratory, Manipur University, Canchipur, Imphal-795 003, Email: nabadwip11@yahoo.co.in) : Computerized glow curve deconvolution on thermoluminescence of Cu-doped borate glass. Indian J pure appl Phys 2004, 42(12), 886-90.

Trapping parameters namely activation energy (E), frequency factor (s) and order of kinetics (b) of thermoluminescence (TL) curve of Cu-doped borate glass have been evaluated using Computerized Glow Curve Decomvolution (CGCD) technique. It is observed that near to temperature 108°C, a prominent peak of Cu-doped borate glass, after various extents of thermal cleaning, was observed obeying second order kinetics with an exponential distribtion of traps of energies in the range (0.853 -1.15) eV and frequency factors in the order of (10¹⁰~10¹¹) s^-1.

5 illus, 4 tables, 16 ref

014343   Singh S N;Pandit S K (Phys Dep, C.M. Science College, Darbhanga, Bihar) : Analytical study of E.M. scattering due to dielectric wedges on geometrical theory of diffraction. Acta Cienc Indica-Phys 2004, 30(4), 437-41.

Approximate uniform asymptotic expressions are provided to determine the field scattered by a penetrable wedge illuminated at normal incidence. The wedge is formed by two thin dielectric slabs having identical geometry and dielectric constants. The solution is limited to wedge angles and the source positions where internal reflections do not occur. The geometrical theory of diffraction is applied for approximation of internal fields to the slab. The results obtained are compared with the theoretical results available in literature.

3 illus, 12 ref

014342   Singh M;Pujara K K;Mohanan V (Mechanical Engineering Dep, Indian Institute of Technology, New Delhi-110 010, Email: mahavir@mail.nplinida.ernet.in) : Analysis of problems to express uncertainties of building acoustic measurements. MAPAN 2003, 18(4), 217-23.

The application of international harmonised measurement standards will be mandatory in the fild of building acoustics in the near future in order to facilitate trade across the borders. The question of the uncertainty of measurement results characterising the acoustical performance of building products is getting growing importance. In ISO 140-2 of 1991 only preliminary and insufficient precision data are given regarding the measurement results when tlie ISO 140 measurement standards are applied. To start the revision in ISO/TC43/SC2/WG18 a comprehensive analysis of several problems is necessary. The expression of precision data by the terms "repeatability" and "reproducibility" will have to be transferred to the quite different procedure according to the "Guide to the expression of uncertainty in measurement" (GUM). Recent inter-laboratory comparison measurements enable the analysis of these problems to be based on realistic figures.

2 tables, 8 ref

014341   Shyam Lal;Saxena M (NO, Moradabad Institute of Technology, Ramganga Vihar, Phase-II, Moradabad-244 001) : Advanced radio interferometry between space and earth (arise). Acta Cienc Indica-Phys 2004, 30(3), 337-9.

Advanced radio interferometry between space and earth (ARISE) is a space very long baseline interferometry (VLBI) mission with a scheduled launch date of 2008. The scientific requirement of delivering 8 Gb/s of data from the spacecraft to a ground station presents technical challenges for telecommunication design.

5 ref

014340   Shyam Lal;Saxena M (NO, Moradabad Institute of Technology, Ramganga Vihar, Phase-II, Moradabad-244 001) : Advanced radio interferometry between space and earth (arise). Acta Cienc Indica-Phys 2004, 30(3), 321-2.

Advanced Radio Interferometry between space and Earth (ARISE) is a space very long baseline interferometry (VLBI) mission with a scheduled launch date of 2008. It consists of an inflatable 25 m radio telescope circulating in a highly elliptical Earth orbit with a perigee of 5,000 km and an apogee of 40,000 km. The objective is to observe in conjunction with Earth-based telescopes to obtain high-resolution maps of quasars and active galactic nuclei for science investigations. ARISE requires an 8-Gb/s downlink of science data, which is a challenge using today's technology.

7 ref

014339   Shukla S;Singh P K;Tiwari R C;Singh L K (Physics and Electronics Dep, Dr. Ram Manohar Lohia Avadh Univ, Faizabad-224 001) : Comparison of electroluminescence in ZnO-CdO and ZnO-CdS base binary systems. Acta Cienc Indica-Phys 2004, 30(3), 271-6.

A comparative study was made of electroluminescence in (ZnO + CdS) : Cu, Mn(H) and (ZnO + CdO) : Cu(Cl) binary systems. Only 15% CdO and 50% CdS is found to be homogeneously soluble in ZnO + CdO and ZnO + CdS systems respectively. The presence of manganese decreases the homogeneity of ZnO-CdO solution and acts as a killer in the system, while it produces a yellow emission band in ZnO-CdS system. The voltage and frequency dependent characteristics were also studied and were found as usual. The ZnO-CdS system may be explored as a double band (green and yellow) emitting electroluminophor, while ZnO-CdO system provides only a green emission band.

5 illus, 1 table, 20 ref

014338   Sharma A K;Verma K K (Physics and Electronics Dep, Dr. R.M.L. Avadh Univ, Faizabad-224 001) : Preparation of TI : HTSC film by chemical spraypyrolysis technique using ultrasonic nebuliser. Acta Cienc Indica-Phys 2004, 30(3), 277-80.

TI : HTSC films have been prepared by chemical spray pyrolysis technique employing ultrasonic nebuliser on MgO (100) and ZrO₂ (100) single crystal substrates through precursor route keeping in view the toxicity of thallium vapour. The Tc(R = 0) of TI: HTSC films on MgO (100) and ZrO₂ (100) are ~98 K and ~88 K respectively. Further structural-microstructural correlation have been done through XRD and SEM.

4 illus, 23 ref

014337   Sewak Singh R;Suresh Singh R;Anzer A;Singh N P;Sinha A K;Verma P K;Mishra L K (Physics Dep, Magadh Univ, Bodh-Gaya-824 234) : An evaluation of viscosity of <. Acta Cienc Indica-Phys 2004, 30(3), 299-308.

The viscosity of dilute mixtures of ³He-⁴He liquid have been evaluated by a theoretical formulism based on Resind et al. The evaluated results show that η increases very sharply and are in poor agreement with the experimmtal data. An empirical formula then has then been used. The results are in good agreement with the experimental data. Constants of the empirical formulas have been obtained.

3 tables, 22 ref

014336   Saxena S K (Physics Dep, Upadhi (P.G) Mahavidyalya, Piliphit-262 001) : An abstract mathematical approach to the scattering amplitude for trace class perturbations. Acta Cienc Indica-Phys 2004, 30(4), 417-20.

Author reported the spectral properties of the scattering of S-P^ac_o by a vector spectral integral. Derived a formula for the scattering amplitude T(λ )with the help of Hilbert Schmidt Opertor and trace operators.

9 ref

014335   Saxena S K (Phys Dep, Upadhi (P.G.) Mahavidyalaya, Pilibhit-262 001) : Asymmetry in electron-hydrogen scattering using two potential formalism. Acta Cienc Indica-Phys 2004, 30(4), 409-16.

Angular distribution of the asymmetry for the 1s-2s transition in the scattering of spin polarized electron with spin polarized hydrogen atom target has been reported used two potential approach with localized exchange and also with the Ochkur-Bonham exchange.

4 illus, 2 tables, 25 ref

014334   Saxena P K;Saxena S (Phys Dep, Barelly College, Barelly) : Spin asymmetry in Na (3s) excitation by e<. Acta Cienc Indica-Phys 2004, 30(4), 425-8.

Excitation of 3s state of Na by electron and positron is studied using two potential approach. The calculaction for asymmetry parameter A and angular correlation parameter λ are performed at energy 60 eV. The computed results are compared with each other. Due to lack of experimental data authors are unable to explain the co-relation between experiment and present theory.

2 illus, 7 ref

014333   Saxena M;Gupta V;Agarwal A (Applied Sciences and Humanities Dep, Moradabad Institute of Technology, Ramganga Vihar, Phase-II, Moradabad-244 001) : A brief review of magneto-optic recording technology. Acta Cienc Indica-Phys 2004, 30(3), 315-8.

About a decade ago, the areal storage density on magnetic disk drives was advancing at a pace of about 25% per year. At that time semiconductor dynamic random access memory was advancing at a pace of about 40% per year. However, recently, the magnetic disk drive industry responded by advancing the rate of progress in areal density to 60% per year. With the recent recording at 10 Gb/in² densities, it is now believed that this rate of progress can be sustained at least into this millennium. Magneto-optic (MO) storage systems record data by thermally heating (with the laser spot) the media under the influence of a magnetic field.

6 ref

014332   Saxena M;Agarwal B B (Applied Sciences and Humanities, Moradabad Institute of Technology, Ramganga Vihar, Phase-II, Moradabad-244 001) : Semiconductors for spin electronics. Acta Cienc Indica-Phys 2004, 30(3), 319-20.

Electrons are elementary particles with a negative etectrical charge and a magnetic moment, called "spin." Spin is a concept from the field of quantum mechanics, and it corresponds to "rotation" in classical mechanics. "Classical" electronics uses electron charge to information. However, these carriers also possess an intrinsic property as their charge and mass, the spin. "Spin" electronics (or spintronics) is based on this additional degree of freedom. This novel field opens a wide range of applications (magnetic memories, sensors...) and physical studies (spin coherence, magnetic properties...).

8 ref

014331   Roy S;Jha H K (Physics Dep, M.S. College, Motihari, Bihar) : Analysis of the scattering from targets on oceanlike rough surfaces. Acta Cienc Indica-Phys 2004, 30(3), 251-4.

The iterative forward-backward (FB) method has been proposed to solve the magnetic field integral equation,(MFIE)for smooth one-dimensional (1-D) rough surfaces. This method is very efficient as converges in a very small number of iterations. This solution becomes unstable when some obstacle, like a ship or a large breaking wave, is included in the original problem which has been presented. The generalized forward-backward (GFB) method to solve such kinds of complex problems. The approach is formulated for the electric field integral equation (EFIE), which is solved using a hybrid combination of the Conventional FB method and the method of moments (MoM), the latter of which is only applied over a small region around the obstacle. The GFB method is shown to provide accurate results while maintaining the efficiency and fast convergence of the conventional FB method. The numerical results show that different random ocean surfaces greatly affect the backscatter patterns, of ship-like target, although the patterns tend to have about the same average level. The purpose of the GFB method introduced here is to provide a numerical tool for studying this class of scattering problems.

1 illus, 6 ref

014330   Rao S U M (National Physical Laboratory, , Dr. K.S. Krishnan Marg, New Delhi-110 012, Email: sumrao@mail.nplindia.ernet.in) : Central issues of reliability physics and their role in development of electronic products. MAPAN 2003, 18(4), 225-34.

The importance of reliability physics has been explained. Various central issues of this multidiscipline subject like materials characterization, process monitoring, environmental stress testing, failure analysis, reliability prediction, etc. have been discussed.

4 illus, 1 table, 20 ref

014329   Rangra V S;Sharma D R (Physics Dep, H P Univ, Shimla-171 005) : Dielectric relaxation studies of binary mixtures of acetone and N-methylacetamide in benzene solution using microwave absorption data. Indian J pure appl Phys 2004, 42(12), 921-5.

The dielectric relaxation times (τ) and the dipole moments (μ) of the binary mixtures of different molar concentrations of acetone (CH₃COCH₃) in the binary mixtures of acetone and N-methylacetamide (NMA) in benzene solutions have been calculated by using standared standing wave microwave techniques and Gopal Krishna's single frequency (9.88GHz) concentration variational method and different temperature (25, 30, 35, 40°C). The dielectric relaxation process has been found to be an activated process. The energy parameters (ΔH_ε, ΔF_ε, ΔS_ε) for the dielectric relaxation process of binary mixtures containing 30% mole-fraction of acetone have been calculated at the respective given temperatures and the comparison has been made with the corresponding energy parameters (ΔH_η ΔF_η, ΔS_{η) for the viscous flow. On the basis of the observations, it is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process. The solute-solute and solute-solvent molecular associations have been predicted.}

3 illus, 3 tables, 16 ref

014328   Prasad R N (NO, , PO-Sahugarh (Hulas), Via & Dist-Madhipura, Bihar) : Optimization of an antenna in lossy medium. Acta Cienc Indica-Phys 2004, 30(4), 429-32.

In the lossy space outside the sphere, the electromagnetic fields are expanded in a complete set of vector wave functions. Optimization of the power gain of an antenna is to maximize the power flow density in one direction for a given input power to the antenna. The radiation eficiency, the directivity and the power gain are defined for antennas in a lossy medium and the optimal values of these quantities have been derived. Simple relations between the maximal number of ports or channels, an antenna can use and the optimal directivity and gain of the antenna have been presented.

1 illus, 6 ref

014327   Prasad R;Gupta R N;Gupata G K (Physics Dept, DDU Gorakhapur Univ, Gorakhpur, ) : Annealing effect on the structure and electrical properties or amorphous Ga As/Ge Multiplayer thin film. Acta Cienc Indica-Phys 2004, 30(4), 421-4.

Amorphous Ga As/Ge multilayer thin films prepared by vacuum evaporation technique, show a difference both in conductivity and activation energy after annealing. This difference is caused by lowering of band gap in the annealed film. The conductivity differences are due to chemical bonding and the resulting electronic state in amorphous lone pair semiconductors. The X-ray results revealed crystalline Ge, Ga and Ga As phase at higher annealing tempreatures. It is also found that the conductivity and the activation energy decrease with the increase of annealing tempereature.

2 illus, 1 table, 15 ref

014326   Pavai R E;Vasantharani P;Kannappan A N (Physics Dep, Annamalai Univeristy, Annamalai Nagar-608 002) : Ultrasonic studies on aqueous ternary electrolytes. Indian J pure appl Phys 2004, 42(12), 934-6.

The density, viscosity and ultrasonic velocity have been measured in two ternary electrolytic mixtures of sodium chloride and manganese chloride in the aqueous mixture of magnesium sulphate and cadmium chloride at 308, 313 and 318 K. From these values the parameters like free volume, internal pressure, solvation number and viscosity B-coefficient have been calculated. The results are interpreted on the basis of ion-ion, ion solvent and structure making/promoting tensency of the electrolytes.

2 tables, 13 ref

014325   Pandit S R;Choubey P N (P.G. Department of Physics, Sahibganj College, Sahiganj S.K.M. University, Dumka, Jharkhand) : Magnitude and temperature variation of phonon thermal conductivity of metals and insulators. Ultra Scient phys Sci 2004, 16(3), 427-31.

In metals electrons dominate while in insulators lattice waves. In semi conductor these two components have the equal importanct. The magnitude of the transported quantity, i.e. heat, soley depends upon the concentration and the mean free path of the electrons and thermally excited phonons. The thermally excited phonons varies as ⁹e-^θ/2T at temperature T, θ being the Debye's temperature. The magnitude of the phonon thermal conductivity is limited by the quantum mechanical interactions of the electrons and lattice waves with lattice vibrations in an ideally pure solid of infinite dimensions, however, in a normally pure sample of finite dimensions the electrons and phononsmake collisions with impurities, lattice defecs and boundaries etc.. The resistivity caused by the impurities and the geometrical factors of the sample is commonly insensitive to the temperature whereas the contribution due to lattice vibrations is strongly temperature dependent. Thus the lattice vibrations mainly govern the temperature dependence of the thermal conductivity of the electrons and the phonons in transport process in a solid. The communication, however, appears to be more competent to meet the experimental findings in respect of magnitude and temperature variation of phonon thermal conductivity of metals and insulators.

1 table, 10 ref

014324   Pandit S R;Choubey P N (P.G. Dep of Physics, Sahibganj College, Sahibganj, S.K.M. Univ, Dumka, Jharkhand) : Quantitative justification of theoretical relations for thermoelectric power of metals. Acta Cienc Indica-Phys 2004, 30(3), 293-8.

The theoretical formulae for thermoelectric power of metals suggested by Sondhiemer and Wilson have partial success in explaining the experimental findings in case of Au, Ag, Cu, K, Na, Kb and Pb under test at normal temperatures. The magnitude of thermoelectric power of metals calculated from the theoretical formulae, is much greater than that observed directly. A partial agreement between Sondhiemer's formula and thermodynamic relation is found in meeting the experimental findings in thermocouples. Thermodynamic relation fails to meet the magnitude of thermoelectric power of individual metals, observed directly. The communication appears to meet the experimental findings in respect of magnitude of thermo power of noble metals. The theoretical expression is not true for the same in a thermo-couple.

3 tables, 8 ref

014323   Pandey R;Singh L K (Physics and Electronics Dep, Dr.R.M.L. Avadh Univ, Faizabad, Uttar Pradesh) : Variation of gain of OP-AMP based amplifiers with varying temperature : A computer simulation. Acta Cienc Indica-Phys 2004, 30(3), 341-7.

Operational amplifiers are one of the most commonly used electronic circuit, it finds application from general circuits to complex analog computation circuits. The Operational Amplifiers are freely used in analog communication circuits also in short almost every analog circuit somehow uses the OPAMP. As in the concept of OPAMP it is assumed that their characteristics do not change with varying temperature or changes very little, this has been explored by simulating a reliable model of OPAMP by PSPICE. The effect of the temperature on the gain of the 741 operational amplifiers have been studied. The operational amplifier used here is μA 741 Macro model of National Semiconductor. The variation of gain of different OPAMP amplifiers have been observed as temperature is varied from 25° to 150° Celsius. For this the temperature dependent components inside the 741 have been taken and their temperature dependent factors have been varried and then temperature is varied to observe effect on the gain.

6 illus, 4 ref

014322   Pandaey R;Shukla S;Singh L K (Physics and Electrics Dep, Dr. Ram Manohar Lohia Avadh Univ, Faizabad-224 001) : Simulation and analysis of an improved astable multivibrator through pspice. Acta Cienc Indica-Phys 2004, 30(3), 309-14.

Astable multivibrators have been proved very useful due to its wide range of applications which may be extended from its analog version as a square wave-generator to digital version as a dock generator. Its has been explored operatianal characteristics through circuit simulation (by PSPICE). By this; the non-triviality and the complexity of existing analysis can be surmounted by simulating some reliable computational model The traditionally known circuit of free running multivibrator is being modified and analyzed through PSPICE by taking a different approach regarding biasing voltage and current gain of transistors. The results in view of these modifications and analysis are then compared to that of existing theories.

5 illus, 7 ref

014321   Oyoko H O;Duque C A;Porras-Montenegro N (School of Physical Sciences, KwaZulu-Natal Univ, Private bag X54001, Durban 4000, South Africa, Email: oyokoh@ukzn.ac.za) : Theoretical study of the effect of applied stress on the binding energy of a donor impurity in GaAs quantum well dot within an infinite potential barrier. Indian J pure appl Phys 2004, 42(12), 908-11.

A theoretical study has been carried out on the effect of applied stress on the binding energy of a shallow monovalent donor impurity in a GaAs quantum well dot (QWD) of square cross-section. In calculations, a variational technique [Csavinzky & Oyokom, Phys Rev B, 43 (1991)9262] within the effective mass approximation has been used. In this model the donor impurity is confined to the QWD by an infinite barrier potential unlike in a previous study [Oyoko et al. J Appl Phys, 90 (2201) 819.] where the barrier potenital was finite. The donor impurity was located at various positions along the axis (Z-direction) of the QWD. The stress was applied along the same axis. The results show that for constant QWD dimensions L_x, L_y and L_z for various donor positions, the binding energy increases with the applie dstress as the donor position varies from on-edge to on-center locations. The binding energy is also found to increase as the QWD length decreases in both cases of on-edge and on-center donor locations for constant L_x and L_y as well as for decreasing QWD size. In all the casesconsidered, the binding energy is much larger for the on-center than for the on-edge positions for the same QWD dimensions and the same applied axial stess. The results obtained show that in experimental study of optical and electronic properties of such nanostructures as QWDs, the effect of stress on donor impurity binding energies should be taken into consideration.

3 illus, 13 ref

014320   Orlovich V A;Kachinski A V;Bui A A; Kopachevsky V D;Grabtchikoy A S;Khodasevich I A;Ermolenkov V V; Apanasevich P A (NO, B.I.Stepanov Intistitutte of Physics, National Academy of Sciences of, ) : Laser system tunable in the 190 - 500 nm spectral range for resonance Raman spectroscopy. Asian Chem Lett 2004, 8(1), 13-19.

The Ti:Sapphire laser system for application in resonance Raman spectroscopy was described. The system allowed to obtain pulse radiation (9 ns, 10 Hz) continuously tunable in the 188.5 - 504 nm spectral range. The average power of 10 - 300 mW in dependence on wavelength was demostrated. The spectral line width was as narrow as 30 pm and it could be further narrowed down to 2 pm.

3 illus, 1 table, 19 ref

014319   Omkar Nath;Naib Singh;Saxena A K;Rao S U M; Singhal R P (National Physical Laboratory, , Dr. K.S. Krishnan Marg, New Delhi-110 012, Email: oknath@mail.nplindia.ernet.in) : Proficiency testing in AC resistance measurement for NABL accredited laboratories-2001/02. MAPAN 2003, 18(4), 243-50.

Results of proficiency testing in the field of ac resistance measurement has been reported. This inter-laboratory inter-comparison has been carried out amongst the NABL accredited calibration laboratories in India, as per MoU between NABL and NPL. A set of four standard resistors having nominal values of 1 Ω, 100 Ω, 1 kΩ and 10 kΩ, has been selected as artifacts. NPL acted as coordinating laboratory and also assigned reference values to these artifacts. The participating laboratories furnished the values measured for these resistors along with their uncertainty in measurement. These values have been analyzed using the standard statistical technique for comparing values. The performance of the participating laboratories in the field of ac resistance measurement has also been evaluated.

2 illus, 4 tables, 9 ref

014318   Nayakulu S V R;Reddy C S;Reddy D L (Phys Dep, T.J.P.S. College, Guntur-522 006) : Ultrasonic studies in binary liquid mixtures of 2-butanol with methyl acetate-application of laidler and eyring treatments. Acta Cienc Indica-Phys 2004, 30(4), 376-82.

Ultrasonic velocity, viscosity and density for binary liquid mixtures of 2-butanol with methyl acetate have been determined at 311.15 K over the entire mole fraction range. From these measured parameters adiabatic compressibility (β_s), intermolecular free length (L_f), acoustical impedance (Z), internal pressure (π_i) and free volume (V_f) have been calculated. The ultrasonic velocity (v) was measured at a frequency of 2 MHz trasnsducer using ultrasonic pulse echo system on 2-butanol in methyl acetate at various concentrations and at 311 K constant temperature. Laidler treatment for dipolar solvent mixtures is applied in these ultrasonic studies. It is found that the ultrasonic velocity (v) increases linearly with increase in 2-butanol in the solvent mixture. This is traced to increase in intermolecular hydrogen bonding. Dipolar interaction in binary mixtures of dipolar solvents causes linear changes in ultrasonic velocity (v), internal pressure (π_i) and free volume (V_f) studies. These dipolar interactions include intermolecular hydrogen bonding present in these solvent mixtures.

5 illus, 2 tables, 17 ref

014317   Misra U D;Kumar N (Physics Dep, Lucknow University, Lucknow-226 007, Email: udmisra@rediffmail.com) : Systematization of L X-ray satellites I: Lα satellites. Indian J pure appl Phys 2004, 42(12), 891-5.

The iterative procedure, based on Hagstrom's method of the doubly modified Moseley plot, has been used for the firs time for the systematization of Lα X-ray satellites for 48 ≤ Z ≤ 80. This has resulted in the identification of a number of satellites measured by certain researchers and removal of anomalies in the measurements of the wavelength of some satellite lines.

2 tables, 26 ref

014316   Mashi A;Singh M;Shrivastava P K (Physics Dep, Govt. Autonomous P.G. College, Shahdol) : High speed plasma streams and cosmic ray intensity variation. Ultra Scient phys Sci 2004, 16(3), 309-12.

High speed plasma streams can be separated into two categories : Flare Generated Streams (FGS) and corotating streams. These plasma streams have been grouped into three classes (short, medium and long) according to their time duration. The influence of all the three categories of high speed plasma streams on cosmic ray intensity has been studied during 1989 to 1994. Our results indicate that all the three categories of streams produce decreases in cosmic ray intensity. However, medium plasma streams are found more effective in producing systematic decrease in cosmic ray intensity on short-term basis.

3 illus, 9 ref

014315   Marghany M;Ting C H (Faculty of Science and Technology, Kolej Universiti Sains dan Teknologi Malaysia, 21030 Mengabang Telipot, Kuala Terengganu, Malaysia) : Comparison of TOPSAR polarized data in mapping coastline change. Ultra Scient phys Sci 2004, 16(3), 301-8.

The study aims to determine the suitable polarized TOPSAR L-HH, L-VV and C-VV band for mapping coastline change. Lee algorithm and combination of linear contrast. Gaussian and histogram equalization enhancement was used to determine the coastline edge morphology. The manual vector layer digitizing was applied to extract the coastline for the different bands. The statistical analysis, t-test was used to finds the significant difference between the TOPSAR bands. Comparison with SPOT and the ground truth data was conducted to determine the best TOPSAR algorithm in coastline change mapping. The co-relation coefficient shows that C-band VV polarization is most appropriate for coastline change detection compared to others band. The t-test shows that there is a significant difference between L- and C-band.

6 illus, 4 tables, 17 ref

014314   Maniu D;Iliescu T;Ardelean I (Faculty of Physics, Babes-Bolyai Univ, Kogalniceanu 1, 3400 Cluj-Napoca. Romania) : Raman spectroscopic investigation of some borate glasses. Asian Chem Lett 2004, 8(1), 7-11.

The influence of Fe₂O₃ and TiO₂, content on the structure of 3B₂O₃.K₂O glass was investigated by Raman Spectroscopy. At low content of iron or titanium ions the Raman spectra do not reveal any structural changes Addition of iron or titanium oxides cause the increases of the number of non-bridging oxygen, the glass structure becomes more randomized "loose" BO₄^- tetrahedra appear. A small number of chain-type metaborate and pyroborate groups are also present in this kind of glass. Iron and titanium ions act as network modifier in these glasses, titanium acting as network modifier only at high concentration.

2 illus, 15 ref

014313   Mahapatra U S;Roy G S;Tripathy S;Maharana L (Physics Dep, K.B.D.A.V. College, Nirakarpur-752 019) : Evaluation of dipole moment of hydrogen bonded complexes of alcohols with amines. Ultra Scient phys Sci 2004, 16(3), 361-8.

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 455 kHz at temperature 303.16K. 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 is found to be greater for n-propanol-n-propyl amine system.

4 illus, 2 tables, 16 ref

014312   Madani J;Ahmad I (Physics Dep, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia) : Microscopic study of proton-deuteron total reaction cross section at medium energies. Ultra Scient phys Sci 2004, 16(3), 417-20.

Applies the Coulomb modified Glauber model to study p-d total reaction cross-section in the incident proton energy range 20 - 50 MeV. The cross section is calculated using the single Gaussian model density for the deuteron. The size parameter of the density is determined from the measured charge rms radius after making correction for the finite proton charge distribution. It is found that the model gives a fairly good account of the experimental data.

1 illus, 15 ref

014311   Liang E J;Ding P;Zhang H R;Moura C;Cunha L (School of Physical Science &. Engineering, Zhengzhou Univ, Zhengzhou-450052, People's Republic of China) : Raman characterization of CN_x nanotubes. Asian Chem Lett 2004, 8(1), 1-6.

A systematic Raman characterization of CN, nanotubes synthesized by thermal decomposition of ferrocene/ethylenediamine mixture at 1053, 1133,1193, 1253, 1293 and 1353K is presented. It is shown that both the full width at half maximum (FWHM) and the relative intensity of the D, G and D* modes are affected by growth temperature, i.e. the degree of disorder. The FWHMs of these modes reduce linearly with increasing growth temperature. The intensities of the D and G modes decrease while that of the D* mode increases with increasing growth temperature, if normalized with respect to the combination band at about 2940cm^-1. Based on these results, new quantitative approaches for estimating the degree of disorder in CN_x nanotubes have been presented and the converse behavior between the D and D* modes have been interpreted in intensity as a correlation of them by K-point phonons.

3 illus, 20 ref

014310   Larsen K L;Nielsen O F (NO, Chemical Institute, Copenhagen Univ, 5-Universitetsparken, DK-2100 Copenhagen, Denmark) : Raman spectroscopic investigations of meteorites. Asian Chem Lett 2003, 7(4), 229-35.

Raman spectroscopy was used to characterize the meteorites Allende, Axtell, Murchison and Murray. Allende and Axtell are carbonaceous meteorites of the type CV3 and Murchison and Murray are carbonaceous meteorites of the type CM2. Two types of exciting lasers were used. A 785 nm diode laser and an Ar-ion laser with an exciting laser wavelength of 514.5 nm. No fluorescence occurred at 514.5 nm. Various sites of the meteorites were investigated by use of a Raman microscope. The minerals olivine and pyroxene were identified. Different spots of the meteorites contained olivine with a different amount of iron and magnesium. Raman spectroscopy was successfully used to characterize the compositions of the quadrilateral pyroxenes.

8 illus, 1 table, 9 ref

014309   Lal T; (National Physical Laboratory, , Dr. K.S. Krishnan Marg, New Delhi-110 012, Email: tlal@mail.nplindia.ernet.in) : Present status of national prototype kilogram of India. MAPAN 2003, 18(4), 235-42.

The SI Unit of Mass, Kilogram, is defined as the mass of an artefact known as the `International Prototype', kept under the custody of BIPM at Paris in France. India being a member of the Convention of the Metre has copy No. 57 of the International Prototype of the Kilogram which is our National Prototype of the Kilogram and serves as the Primary Standard of Mass. Under the Subordinate Legislations of the Stnadards of Weights and Measures Act of 1957, the National Prototype Kilogram is kept under the custody of the National Physical Laboratory (NPL), New Delhi. Under the Rule 16, Chapter III of the Standards of Weights and Measures (National Standards) Rules, 1988, NPL shall arrange, to get calibrated the national prototype kilogram with international prototype kilogram at periodic interval of not more than ten years and shall publish such values periodically but in any case at least once in every five years. The fourth calibration of the National Prototype Kilogram has been recently carried out by BIPM. In view of mandatory responsibility, the present status of the National Prototype Kilogram, its measurement results and comparative analysis of the mass values assigned to this kilogram, since 1955, have been reported in this paper.

3 illus, 2 tables, 11 ref

014308   Kurien S;Sebastian S;Mathew J;George K C (Physics Dep, SB College, Changanacherry Kottayam, Kerala) : Structural and electrical properties of nano-sized magnesium aluminate. Indian J pure appl Phys 2004, 42(12), 926-33.

The effects of temperature, frequency, and molarity on the dielectric behaviour and ac electrical conductivity have been studied for nanosized samples of MgAl₂O₄ prepared by chemical co-precipitation technique. X-ray powder diffraction (XRD) study shows that ther particle size is 8 nm and the system is orthorhombic. FTIR studies have been used to confirm the formation of the resultant compound. The variations of dielectric constant (ε'), the loss tangent (tanδ) as a function of frequency (200 Hz - 4 MHz) and the temperature (303-450 K) have also been studied. The experimental results indicate that the real dielectric constant (ε'), tanδ, and logσ increase with temperature and then decrease. The dielectric constant (ε'), and tanδ, decrease while the ac conductivity (σ_ac) increases as the frequency increases.

illus, 22 ref

014307   Kumar A (Physics Dep, , Adarsh Nagar, Ward No.-9, at and P.O.-Madhipura-852 113) : Analysis of quantum correlations in optics. Acta Cienc Indica-Phys 2004, 30(3), 245-50.

The analysis of quantum correlations has been presented. Two-photon processes have the potential of generating nonclassical states of light. Many quantum effects have been observed experimentally in dissipative nonlinear systems producing correlated two-photon states. A description of the various nonclassical and nonlocal features is given in terms of the parameters of the Wigner distribution function of the fields generated in a large class of nonlinear processes. The field acquires quantum features only certain ranges of the Wigner parameters. This may provide a unifying description of the known quantum features of the radiation field.

16 ref

014306   Konorov S O;Akimov D A;Ivanov A A;Alfimov M V;Beloglazov V I;Skibina N B;Zheltikov A M (Physics Dep, International Laser Center, M. V. Lomonosov Moscow Stale Univ, 119899 Moscow, Russia) : Microstructure-fiber frequency converters of ultrashort pulses for cross-correlation FROG CARS. Asian Chem Lett 2004, 8(1), 71-9.

A new source of tunable radiation for femtosecond nonlinear spectroscopy is demonstrated. This source is based on nonlinear-optical spectral transformations of ultrashort pulses in microstructure fibers - a novel class of fibers where a solid cladding, typical of standard optical fibers, is replaced by a silica air microstructure cladding. Such fibers provide a high efficiency of frequency upconversion of regeneratively amplified femtosecond pulses of a Cr forsterite laser, permitting the generation of subpicosccond anti-Stokes pulses with a smooth temporal envelope and a linear positive chirp. These pulses from a microstructure fiber were used to measure the spectra of coherent antirStokes Raman scattering (CARS) of toluene solution by cross-correlating these pulses with the femtosecond second-harmonic output of the Cr: forsterite laser in boxcars geometry (XFROG CARS).

5 illus, 58 ref

014305   Knopp G;Beaud P;Radi P;Tulej M;Gerber T (NO, Paul Scherrer Institut, CH-5323 Villigen, Switzerland, Email: gregor.knopp@psi.ch) : Collision-induced line broadening and mixing probed by femtosecond CARS. Asian Chem Lett 2003, 7(4), 237-42.

t is shown that measuring the pressure dependence of femtosecond coherent anti-Stokes Raman scattering (fs-CARS) provides a powerful tool for the investigation of collision-induced line broadening and mixing effects and for the validation of rotational energy transfer (RET) models. Here the angular momentum and energy corrected sudden approximation (AECS) was applied, which justifies the use of an exponentially limiting parameter for the angular momentum transfer L_c ≈ 2 h. A collision cross section of 48.46 ± 0.25 A^o2, an average rotational linewidth of 46.1(3) mK/Amagat and the collision duration of 2πτ_c~210 fs for N₂-N₂ collisions at room temperature could be deduced from the experiment.

3 illus, 1 table, 24 ref