002332   Thakur G C;Jha A (P.G. Dep of Physics, C.M. Science College, Darbhanga, Bihar) : Electromagnetic scattering by penetrable bodies on moment method. Acta Cienc Indica-Phys 2003, 29(1), 93-7.

Envisages to study the electromagnetic scattering by penetrable bodies. The theory of the potential integral equations method is developed for general penetrable scatterer and then applied to the case of purely dielectric scatterer. The integral equations system is solved by the method of moments in combination with cubical mesh. Numerical results of the transmitted and the scattered fields are compared with existing analytical & experimental results which shows a good agreement.

1 illus, 6 ref

002331   Sudarshan E C G;Duck I M (Physics Dep, Center for Particle Theory, Austin TX 78731, USA) : What price the spin-statistics theorem. Pramana J Phys 2003, 61(4), 645-53.

Examines a number of recent proofs of the spin-statistics theorem. All, of course, get the target result of Bose-Einstein statistics for identical integral spin particles and Fermi-Dirac statistics for identical half-integral spin particles. It is pointed out that these proofs, distinguished by their purported simple and intutitive kinematic character, require assumptions that are outside the realm of standard quantum mechanics. Constructs a counter example to these non-dynamical kinematic `proofs' to emphasize the necessity of a dynamical proof as distinct from a kinematic proof. Sudarshan's simple non-relativistic dynamical proof is briefly described. Finally, it makes clear the price paid for any kinematic `proof'.

22 ref

002330   Srivastava S K (Physics Dep, Government Autonomous Post Graduate College, Ambikapur (Chhattisgarh)) : Statistical analysis of rain drop size distribution on specific attenuation for microwave communication in Surguja area. Acta Cienc Indica-Phys 2003, 29(1), 27-30.

The lower atmosphere above the earth surface is absorptive, dispersive and homogeneous and therefore plays an important role in radio wave communication in the frequency range UHF to mm waves. At lower frequencies, the effect of atmospheric precipitation (rain) is not significant, however for higher frequencies it affects severely. Presents the statistical model to calculate the specific attenuation caused by rain on rain drop size data collected over Surguja region.

2 illus, 6 ref

002329   Srivastava K K P;Sinha K K;Banerji D;Ghose S (Physics Dep, T M Bhagalpur University, Bhagalpur-812 007) : Mossbauer, EPR and IR studies of some (Pb,Fe)TiO<. Indian J Phys-Pt A 2003, 77(6), 571-4.

Perovskites of ABO³ structure, like well known PbTiO³ and BaTiO³, have dielectric constants of a few hundred. Several ceramics synthesised partially with other divalent, tetravalent and pentavalent atoms show high dielectric constants and behave as relaxors, useful for electronic components, and hence their characterisation is important. Mossbauer, EPR and IR methods are effective for polycrystalline materials containing some iron, and therfore lead and strontium titanates with Fe were prepared for studies by these techniques. Strontium titanate, cubic at 295 K, was chosen as a reference lattice to see how iron doping changes its structural properties. Their IS, QS and g-values correspond to Fe (III) state. The strong IR bands at around 410 and 600 cm^-1 arise from the TiO₆ and FeO₆ polyhedra respectively.

4 illus, 8 ref

002328   Srivastava K K P (Physics Dep, T M Bhagalpur University, Bhagalpur-812 007) : Magnetic relaxation in nano-particle: a mossbauer study. Indian J Phys-Pt A 2003, 77(6), 553-9.

Ultra-fine superparamagnetic particles of iron compounds with size 50 to 125 A probed through Mossbauer spectroscopy usually show magnetic relaxation effects at low temperatures. A magnetic sextet is observed for long relaxation times compared to nuclear lifetime whereas the magnetic interaction disappears for short relaxation times and this change ususally occurs between 25 to 100 K. A theoretical model has been developed for the magnetic relaxation process considering that on microscopic level it invovles an exchange of energy between magnon and phonon sub-systems via magnon-phonon scattering induced by dynamic exchange. It is seen that the relaxation rate increases with temperature in a complicated manner besides its dependence on the number of magnetic ions or particle-size. The calculated rates appear consistent with the observed Mossbauer results at low temperatures for some of the iron oxides.

1 table, 24 ref

002327   Soper D E (Institute of Theoretical Science, University of Oregon, Eugene, OR 97403-5203, USA) : Partons and jets at the LHC. Pramana J Phys 2003, 61(5), 793-802.

Reviews some issues related to short distance QCD and its relation to the experimental program of the large hadron collider (LHC) now under construction in Geneva.

11 illus, 16 ref

002326   Smarandache F (NO, University of New Mexico, Gallup, NM 87301, USA) : An introduction to the neutrosophic probability applied in quantum physics. Bull pure appl Sci-Sect D 2003, 22(1), 13-25.

Generalizes the classical probability and imprecise probability to the notion of "neutrosophic probability" in order to be able to model Heisenberg's Uncertainty Principle of a particle's behavior, Schrodinger's Cat Theory, and the state of bosons which do not obey Pauli's Exclusion Principle (in quantum physics). Neutrosophic probability is close related to neutrosophic logic and neutrosphic set, and etymologically derive from "neutrosophy".

68 ref

002325   Sinha S K;Choudhary R N P;Choudhary S N (University Dep of Physics, T M Bhagalpur University, Bhagalpur-812 007) : Phase transition in Pb (Mg_1/4Co_1/4W_1/2)O₃ ceramics. Indian J Phys-Pt A 2003, 77(6), 623-6.

Polycrystalline samples of Pb(Mg_1/4Co_1/4W_1/2)O₃ ceramics were prepared by the high-temparature solid-state reaction technique. Preliminary crystal structure and microstructure of the compund at room temperature were studied using the X-ray diffraction (XRD) technique and scanning electron microscopy (SEM) respectively. Detailed dielectric studies suggest that the compund undergoes successive phase transitions at 87°C and at 105°C. Variation of de conductivity as a function of temperature suggests the semiconductor characteristics of the material.

5 illus, 18 ref

002324   Sinha K P;Varma P K;Mishra L K (Physics Dep, B.D. Evening College, Patna, Bihar) : Evaluation of real and imaginary part of the surface contribution to the charge self energy as a function of the distance from metal vacuum surface. Acta Cienc Indica-Phys 2003, 29(2), 149-57.

Using formalism of F-Soles and R.H.Ritchie [Solid State Commun. 63, 245 (1987), evaluates the real and imaginary part of the surface contribution to the charge self energy as a function of metal-vacuum surface for different values of parameter μ. Determines Σ_s(z) as a function of z for three metal surface Al, Na and K in both regimes below and above threshold. The analysis indicates that below the threshold small symmetric oscillations start to appear where as above threshold oscillations on each side begin to differentiate.

6 tables, 23 ref

002323   Singh V R;Singh S K (P.G. Department of Physics, College of Commerce, Patna-800 020) : Thermal analysis of a passive solar still. Acta Cienc Indica-Phys 2003, 29(3), 277-82.

Thermal analysis of a single basin passive solar still is presented in terms of system design and climatic parameters. Experssion for thermal efficiency has been derived and calculation is carried for small water mass in the basin. It predicts the effect of various parameters on the performance of the system.

6 ref

002322   Singh S P;Singh N K (Physics Dep, L.N. Mithila University, Darbhanga-846 004) : Study of input-impedance of a probe-fed stacked patches. Acta Cienc Indica-Phys 2003, 29(3), 253-8.

The theoretical study of input impedance of a microstrip patch consisting of two circular microstrip disks in a stacked configuration driven by a coaxial probe is made. An analysis is performed using a dyadic Green's functions formulation where the mixed boundary value problem is reduced to a set of complex vector integral equations. Galerkin's method is employed in the spectral domain where two sets of disk current expansion are used. The input impedance of the stacked patch including the probe self-impedance is calculated on a function of the layered parameters and the ratio of the two disk radii.

2 illus, 14 ref

002321   Singh R P;Dadhwal V K (Crop Inventory and Modeling Division, Agricultural Resources Group, Sp, , Ahmedabad-380 015) : Comparison of space-based microwave polarization difference index and normalized difference vegetation index for crop growth monitoring. Indian J Radio Space Phys 2003, 32(4), 193-7.

Passive microwave radiometry application for regional assessment of crop growth in India. Brightness temperature (T_B) of various vegetation classes observed at 37 GHz using special sensor microwae imager (SSMI) data, during Kharif season in 1999 in India are analyzed. Vertical as well as horizontal polarization brightness temperature is used to derie microwave polarization difference index (MPDI) for different crops/vegetation classes at various phenological stages. This MPDI index is related with the ten-day maximum value of composite of normalized difference vegetation index (NDVI) data of NOAA-AVHRR sensor. A non-linear inverse relationship has been developed between the MPDI and NDVI of different crops over varous regions. It has been observed that the surface wetness/soil moistue in rice growing region influenced the MPDI-NDVI relationship.

2 illus, 2 tables, 15 ref

002320   Singh R K;Singh S N (NO, L.N. Mithila University, Darbhanga-846 004, Bihar) : Composite equivalent Sc resistors and their study. Acta Cienc Indica-Phys 2003, 29(3), 273-6.

The recent developments of switched capacitor (SC) networks in circuit theory has generated a substantial amount of interest in the field of network analysis and synthesis. In the study the equivalent resistors have been produced by Sc networks. The study of such resistors is made implemented with op-amp. The characteristics of the network is compared with that of conventional one.

3 illus, 1 table, 12 ref

002319   Singh P;Gupta C B (Physics Dep, B.S.A. College of Engg & Tech, Mathura (U.P.)) : Hydromagnetic free convective flow through a porous medium with variable permeability bounded by an infinite moving vertical plate. Acta Cienc Indica-Phys 2003, 29(1), 39-46.

An analysis of the effect of moving infinite vertical plate on free convective two dimensional unsteady flow of a viscous incompressible fluid through a porous medium subjected to a uniform suction is presented under the influence of a uniform transverse magnetic field. The permeability of the porous medium fluctuates in time about a constant mean. Evaluates the velocity distribution u, fluctuating part of velocity profile M_r, M_i and the skin friction at the plate by using the perturbation technique. Investigates the effect of M (Hartmann No.), K₀ (Porosity Parameter) and Q (Velocity Ratio) on velocity and skin firction with the help of Graphs.

4 illus, 4 tables, 14 ref

002318   Singh N K;Choudhary R N P (Physics Dep, V K S University, Ara-802 301) : Studies of structural and electrical properties of some tungsten-bronze ferroelectric ceramics. Indian J Phys-Pt A 2003, 77(6), 627-31.

Polycrystalline samples of Ba₅RTi₂ZrNb₇O₃₀[R=Sm, Gd] of Tungsten Bronze (TB) structural family have been prepared by a high temperature solid state reaction technique, X-ray diffraction (XRD) analysis as a function of temperature shows the orthorhombic structure of the compounds at room temperature. Dielectric studies at four different frequenceis, 1,10, 100 kHx and 1 MHz, show that the above compounds have ferroelectric phase transition of diffuse type, and also have relaxor properties.

5 illus, 1 table, 15 ref

002317   Singh K;Srivastava T K (Solid State Physics and Electronics Dep, Dr. R.M.L. Avadh University, Faizabad, U.P.) : Relationship between absolute hardness parameter and birefringence/polarizability of liquid crystalline materials. Acta Cienc Indica-Phys 2003, 29(2), 169-70.

The hardness parameter of liquid crystalline materials have been calculated. On the other hand the birefringence/polarizability of liquid crystalline materials have been taken. A comparative study has been made between the calculated hardness values and birefringence/polarizability of liquid crystalline materials and the variation between hardness parameter and birefringence/polarizability has been given.

1 table, 3 ref

002316   Singh J;Jha L (University Department of Physics, L.N. Mithila University, Darbhanga-846 004) : Theoretical study of microstrip line on a substrate with continuous permittivity. Acta Cienc Indica-Phys 2003, 29(2), 203-9.

Provides theoretical study of microstrip lines on a substrate with continuous permittivity profile. The arbitrary shapes and inhomogeneous properties of the structure are analysed using the edge based in finite elements with three components of the electric field. The infinite element has a linear and quadratic shape functions, in the shared segment direction, for the transverse and axial components, respectively. Any decaying function can be assumed in the radial direction for all components. This approach provides a direct solution for the propagation factor eliminates the spurious solutions. Using the boundary conditions for perfect conductors at the planes of symmetry reduces the matrix size of the problem. Numerical results are given to show the validity and use fullness of the method.

4 illus, 8 ref

002315   Singh B;Singh D P (Physics Dep, Punjabi University, Patiala-147 002) : Comparative study of the various refractive index mixing rules for ternary liquid mixtures. Acta Cienc Indica-Phys 2003, 29(1), 11-16.

A comparative study of the various refractive index mixing rules due to Lorentz-Lorentz. Gladstone-Dale. Wiener, Heller, Arago-Biot, Eykman, Oster and Newton has been made using experimentally measured density and refractive index data for five ternary liquid mixtures at 313.5 K. From the obtained results, it is point out that though all the mixing rules perform well within the experimental error but the performance of Arago-Biot (A-B), Lorentz-Lorentz (L-L_ and Gladstone-Dale (G-D) relations is comparatively better than those of others.

3 tables, 10 ref

002314   Shoba Kumari;Jha L (University Dep of Physics, L.N. Mithila University, Darbhanga, Bihar) : Gain enhancement method for microstrip antennas. Acta Cienc Indica-Phys 2003, 29(1), 99-101.

Gain is the most important performance parameter of an Antenna. Explains the Process of gain evaluation. It has been demonstrated that extremely high directive gain of a microstrip antenna may result at any scan angle, with practical materials, if the thickness of the Substrate and multiple superstrate layers is chosen properly. Some numerical results illustrate the gain enhancement method.

1 table, 6 ref

002313   Shinde G N;Mirkute P R (Res Lab Electronics, Electronics Dep, Yeshwant Coll, Nanded-431 602) : Low pass second order active-R filter without feed forward input signal for noninverting terminal. Bull pure appl Sci-Sect D 2003, 22(1), 35-7.

The active-R filter design techniques are based on single pole model of op amp. Second order active-R circuit having input at noninverting input without feedforward signal shows better pass band gain for different values of center frequency f_o. The circuit provides only low pass filter function for moderate value of Q.

2 illus, 5 ref

002312   Shinde G N;Achole P D;Mirkut P R (Research Labortory in Electronics Dep, Yeshwant College, Nanded-431 602) : Second order active-R filter with multiple feedback for different Q. Indian J Phys-Pt B 2003, 77(2), 237-9.

A second order active-R filter with multiple feedback is proposed. The negative feedback at inverting input of first op.amp. through R₁,R₂ and also feedback through noniverting input form inverting input of first op.amp, are introduced. It gives three basic filter functions, Low pass, High pass and Band pass at different terminals. It is suitable for high frequency operation, monolithic IC implementation. It gives high passband gain and high value of Q. it can be used for narrow band as well as wide band filters functions. The Q has lower limit (Q > 0.02).

4 illus, 9 ref

002311   Sharma A K;Ahlawat D S;Singh R D (Phys Dep, M.D. Univ, Rohtak-124 001) : Study of substituents in coumarin-450 by nitrogen laser. Bull pure appl Sci-Sect D 2003, 22(1), 45-9.

The gain spectra of C-450 in tethanol at different concentrations have been studied by Nitrogen Laser excitation with the aim to understand the laser behaviour of C-450. The dependence of gain on many experimental parameters and characteristics have been investigated. The concentration dependence of gain, peak wavelength and threshold pump intensity; intensity dependence of optical gain; pump intensity dependence of gain and efficiency; and effect of laser wavelength on gain are the various measurements made. The results obtained have been explained on the basis of the presence of substituent groups, the possibility of TICT state formation, and the non-rigid behaviour of the dye.

5 illus, 7 ref

002310   Sarma A D;Madhu T;Murthy Sarma N S (R & T Unit for Navigational Electronics, Osmania University, Hyderabad-500 007) : An ionospheric time delay model based on IRI-90 for space-bound objects within 300 km altitude. Indian J Radio Space Phys 2003, 32(3), 148-53.

A new time delay model is proposed based on International reference ionosphere-1990 (IRI-90) electron density model for space-bpound objects for any altitude up to 300 km. When limited portion of the ionosphere is considered, Klobuchar's time delay algorithm is not suitable. The procedure used for developing the α and β coefficients is outlined. Important steps of the proposed algorithm are presented. The predicted and theoretical models compare well. An example estimation is given and the results are found to be encouraging.

3 illus, 10 ref

002309   Sarkar P K;Nandy M (H.P.Unit, Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700 064) : Quantum molecular dynamics approach to estimate spallation yield from p+<. Pramana J Phys 2003, 61(4), 675-84.

The spallation yield of neutrons and other mass fragments produced in 800 MeV proton induced reaction on ²⁰⁸Pb have been calculated in the framework of quantum molecular dynamics (QMD) model. The energy spectra and angular distribution have been calculated. Also, multiplicity distributions of the emitted neutrons and kinetic energy carried away by them have been estimated and compared with the available experimental data. The agreement is satisfactory. A major contribution to the neutron emission comes from statistical decay of the fragments. For mass and charge distributions of spallation products the QMD process gives rise to target-like and projectile-like fragments only.

5 illus, 3 tables, 10 ref

002308   Sarkar A D;Khanra B C (Condensed Matter Physics Group Dep, Saha Institute of Nuclear Physics, 1/AF, Bidhan Nagar, Kolkata-700 064) : Effect of alloying on the kinetics of Co+O₂ and CO+NO reactions on Pt-Rh nanocatalysts:a theoretical model. Indian J Phys-Pt A 2003, 77(6), 603-7.

Surface Chemistry Reaction Model has been used to study the kinetics of CO + NO and CO + O₂ reaction on Pt-Rh nanocatalysts. For CO + O₂ reaction the alloy particles evince an intermediate behaviour; bowever, for the CO + NO reaction the alloy particles show no synergistic effect of alloying. The inherent rate of CO + O₂ reaction is much higher than that of CO + NO reaction on the Pt₅₀ Rh₅₀ nanoparticles. The kinetics of the CO + NO + O₂ and CO + NO reaction on teh alloy particles are almost the same. NO inhibits formation of CO₂ molecules. The simulated results are in qualitative agreement with the experimental findings.

3 illus, 3 tables, 12 ref

002307   Sanyal S (NO, Institute of Physics, Sachivalaya Marg, Bhubaneswar-751 005) : Effect of pre-existing baryon inhomogeneities on the dynamics of quark-hadron transition. Pramana J Phys 2003, 61(5), 1033-7.

Baryon number inhomogeneities may be generated during the epoch when the baryon asymmetry of the universe is produced, e.g. at the electroweak phase transition. These lumps will have a lower temperature than the background. Also the value of T_c will be different in these regions. Since a first-order quark-hadron (Q-H) transition is susceptible to small changes in temperature, it investigates the effect of the presence of such baryonic lumps on the dynamics of the Q-H transition. It finds that the phase transition is delayed in these lumps for significant overdensities. Consequently, argues that baryon concentration in these regions grows by the end of the transition. It mentions some models which may give rise to such high baryon on overdensities before the Q-H transition.

5 ref

002306   Sahu P K;Ohnishi A (NO, Institute of Physics, Sachivalaya Marg, Bhubaneswar-751 005) : Radial, sideward and elliptic flow at AGS energies. Pramana J Phys 2003, 61(5), 1027-32.

Studies the baryon transverse in-plane (sideward) and elliptic flow from SIS to AGS energies for Au+AU collisions in a relativistic dynamical simulation model that includes all baryon resonances up to a mass of 2 GeV as well as string degrees of freedom for the higher mass continuum. There are two factors which dominantly determine the baryon flow at these energies: the momentum dependence of the scalar and vector potentials and the resonance-string degrees of freedom. Fixes the explicit momentum dependence of the nucleon-meson couplings of NL3(hard) equation of state (EoS) by the nucleon optical potential up to 1 GeV of kinetic energy. Simultaneously it reproduces the sideward flow, the elliptic flow and the radial transverse mass distribution of protons data at AGS energies. In order to study the sensitivity of different mean-field EoS, it uses NL2(soft) and NL23(medium) along with NL3(hard) momenta-dependent mean-field EoS. It finds that to describe data on both sideward and elliptic flow, NL3 model is better at 2 A-GeV, while NL23 model is at 4-8 A-GeV.

3 illus, 13 ref

002305   Roychowdhury A P (NO, Manga Noor Koman, Pattom, Trivandrum (Kerala)) : Kinematic representation of the dynamic navier-stokes equation. Acta Cienc Indica-Phys 2003, 29(3), 283-90.

The dynamic form of the Navier-Stokes equation is mapped to a kinematic description of fluid motion. The pseudo acceleration induced body force terms are absent in the kinematic representation.

2 illus, 13 ref

002304   Roy S K (Physics Dep, Government Polytechnic, Darbhanga-846 004) : Study of antenna directivity. Indian J Radio Space Phys 2003, 32(3), 177-81.

Although more rigorous treatments have been developed for the antenna directivity, the directivity, including phase shift factors, for several types of uniformly excited planar arraysis obtained. The agreement between the theory and experimental result is found to be excellent.

6 illus, 5 ref

002303   Roy R S;Singh A K;Ravindra Kumar;Sinha U K; Sangita Kumari;Singh V;Prasad R N;Roy A K (P.G. Department of Physics, Rajendra College (J.P. Univ.), Chapra, Bihar) : Potophysical and photochemical properties of dye molecules used for fluorescent solar concentrators. Acta Cienc Indica-Phys 2003, 29(2), 171-5.

Properties of dye molecules in polymers used for solar concentration have been presented. The essential features of all dye molecules used for fluorescent solar concentrators are high extinction coefficient, strong fluorescent properties, a high quantum yield and a long photostability. Absorption and emission spectroscopic techniques are applied to study some dye molecules, Fluorescent, eosine, erythrosine, rhodamine B, rhodamine 6G, acridine orange, alone and in solution (Polyethylene glycol 400, 600, 700), in order to establish the change in photostability of these days, that could be used for fluorescent solar concentrators.

1 illus, 3 tables, 10 ref

002302   Rastogi N;Saxena M;Agarwal A;Singh S (Sciences and Humanities Dep, Moradabad Institute of Technology, Ram Ganga Vihar, Phase II, Moradabad-244 001) : Effect of killer impurities (Fe, Co and Ni) on electron escape probabilities and trap depths in II-VI semiconductors. Acta Cienc Indica-Phys 2003, 29(3), 263-6.

In Spectroscopic property of II-VI semiconductor, a study of decay curves of photocurrent have been used to calculate the probability of escape of an electron from the traps per second and the trap depth. It has been found that the shallow and deep traps are situated at different energy depth in ZnS : Cu, O (Fe, Co and Ni) photoconductor. The effect of Fe, Co and Ni impurities on the probability of escape of an electron from the deep traps is entirely different. Iron has been found to increase this probability in ZnS : Cu, O lattice while Cobalt and Nikel reduce it. The p-value in all the photoconductors decreases as the time along the decay curve increases. The effective trap depth of shallow traps increases while that of deep traps decreases due the presence of iron, cobalt and nickel impurities.

2 illus, 2 tables, 8 ref

002301   Rastogi N;Saxena M;Agarwal A;Singh S (Sciences and Humanities Dep, Moradabad Institute of Technology, Ram Ganga Vihar-Phase II, Moradabad) : Transient effect in ZnS : Cu, Co, O and (ZnO-MgO) : Fe, O photoconductors. Acta Cienc Indica-Phys 2003, 29(2), 165-8.

Applications of a voltage across sample cause the free carriers to rush into the conduction band from the reservoir at the cathode. In the absence of traps, space charge pattern and steady state current may be formed in one or two transit times. The initial current equal to that due to free carriers in the absence of traps would have been obtained in the presence of traps subjects to the fact that trapping time should be longer than the transit time. It was observed that photocurrents increased when the incident radiation is cutoff in the case of ZnS: Cu, Co, O. It is found that number of bands present in MgO in the range 4 eV and 6 eV are due to the crystal defects, but not it is expected that these be due to the presence of iron impurity in two different states.

2 illus, 19 ref

002300   Rao B R M;Krishna Murthy K;Reddy G R C (Physics Dep, L.B. Reddy College Engineering, Mylavaram-521 230) : PSF corrolaries of the optical systems apodised with the hamming amplitude filters. Acta Cienc Indica-Phys 2003, 29(3), 235-40.

A few corollaries of the Point Spread Function (PSF) for the circular and annular optical systems apodised with the Hamming amplitude filters, have been studied with a view of estimate the performance of apodisation filter as the goal of apodisation is to improve selected aspects of the imaging performance of the optical system. These are the second moment, Strehl ratio, total transmission factor and the maximum negative amplitude. The twelve point Gaussian quadrature numerical integration method has been employed.

2 illus, 2 tables, 9 ref

002299   Purohit G;Bhullar A S;Sud K K (Physics Dep, , Udaipur-313 002) : (e,2e) triple differential cross sections of He, Ne, Ar, Kr and Xe atoms in coplanar to perpendicualr plane geometry. Indian J Phys-Pt B 2003, 77(2), 197-84.

Results of calculation of triple differential cross section in distorted wave Born approximation (DWBA) on He (1s²), Ne (2p⁶, Ar (3p⁶, Kr (4p⁶) and Xe(5p⁶) targets at incident electron energy which is 20 eV above ionization potential as well as at an incident energy of 64.6 eV. Results have been compared the recent available experimental data on helium, neon and argon targets and the role of post collisional interaction have been presented and effect of target polarization on TDCS have been reported. It has been observed that the role of polarization potential becomes significant as nulcear charge increase. Further it has been observed that the trend in variation of TDCS with the symmetric scattering angle for He atom is different from Ne, Ar, Kr and Xe atoms in perpendicular plane geometry.

7 illus, 27 ref

002298   Prasad R K;Rahman M S;Rai K D P;Singh F B (Physics Dep, Womens College, Samastipur-848 101) : Nature of thermopower determines the metallic character of the metal. Acta Cienc Indica-Phys 2003, 29(2), 177-83.

It is known that even a small amount of impurity in the host Metal changes the magnitude as well as sign of the Thermopower. This observed thermopowers are the resultant of the characteristics as thermopower of impurity Metal (host metal) and the thermopower of the impurity Metal. There is a tendency to loose electron and hence they are electro positive, hence act electron, this inonisation potential will be less, greater will be its reducing power and higher its metallic character. But large lonisation potential means weak metallic character as its tendency to loose electron is restricted. Generally thermopower of a strong metal is negative and that of a weak metal is positive. So, the nature of thermopower determines the metallic character of the Metal.

4 illus, 1 table, 14 ref

002297   Prasad K;Choudhary S N;Choudhary R N P (University Department of Physics Dep, Tilka Manjhi Bhagalpur University, Bhagalpur-812 007) : Structural and diellectric properties of KLiMoO₄ ceramic. Indian J Phys-Pt A 2003, 77(6), 619-22.

Potassium lilthium molybdates (KLiMoO₄) ceremic has been prepared by solid state reaction technique. Preliminary structural study suggests the formation of single phase (monoclinic) compound at room temperature. The variation of dielectric constant and loss as a function of temperature (from room temperature to 250°C) at 1 kHz and 10 kHz exhibits dielectric anomaly and sequential phase transitions at T_c1 = 134°C amd T_c2 = 48°C respectively. A comparison of various properties of KLi (Mo_xW1-x)O₄; x = 0 [ J. Mater. Sci. Lett., 16 1807 (1997)], 0.5 [J.Mater.Sci. Lett., 18 501 (1999)] and 1.0 ceramics have also been made. The ferro-paraelectric phase transition (T_c1 has been found to be first order Curie-Weiss type.

6 illus, 21 ref

002296   Prasad H;Rafique S M;Singh B N (NO, , Sahebganj, Champanagar, Bhagalpur-812 007) : Energetic Harrison's first principle approach to the transport properties of metal: Mg and Ga. Indian J Phys-Pt A 2003, 77(6), 641-3.

Harrison's First Priciple (HFP) method owes its existence to the concept of orthogonalised plane wave (OPW). In this technique, the beauty lies in the factorization of the matrix element of the crystal potential into form factor w(k,q) and the structure factor a(q). The latter is available from experimental either though X-ray or neutron diffraction but the former is to be calculated theoretically by suitable theoretical framework. In Harrison's First Principle method, there is no arbitrary adjustable parameterization and no arbitary model of portential is chosen, rather all the contirbuting potentials are derived from basic considerations. However, there is a controversy regarding the choice of eigenvalues of the core states. This is due to the fact that different self-consistent computations lead to eigenvalues which differ markedly, amongst themselves. The impact of various eigenvalues have been studied both on the form factor w(k,q) and electrical resistivity (R) derived from Ziman's formalism and also Knight shift (K) of Mg and Ga. The study reveals interesting features.

1 illus, 1 table, 7 ref

002295   Prasad D;Jha A (Post Graduate Department of Physics, C.M. Science College, Darbhanga-846 004) : Study on electromagnetic hyperthermia and cancer therapy. Acta Cienc Indica-Phys 2003, 29(3), 309-12.

The use of electromagnetic power for therapeutic applications has existed since electromagnetic sources have been available to man. Microwave hyperthermia is promising adjunct for cancer therapy. Experimental and clinical research indicate that these responses will occur as a result of elivating the tissue temperatures. A simple expression for the radio frequency power absorbed by any biological sample irradiated in a TEM Cell is derived. Selected cancer statistics and hyperthermia considerations are described in Table for further considerations.

1 illus, 1 table, 7 ref

002294   Poonam Kumari;Jha L (Physics Dep, Mithila University, Darbhanga-846 004) : Theoretical study of the effects of parasitic element on the bandwidth of a microstrip antenna. Acta Cienc Indica-Phys 2003, 29(1), 47-50.

An analytical technique to study the effects of size and position of a parasitic element on the bandwidth of a stock rectangular microstrip antenna is presented. In the spectral domain on integral equation for the unknown patch current densities is formulated. The Galerkin procedure is employed to solve the integral equation. The theoretical result is important for bandwidth enhancement of the microstrip antenna.

1 illus, 1 table, 10 ref

002293   Phatak S C (NO, Institute of Physics, Bhubaneswar-751 005) : Dihyperons in chiral color dielectric model. Pramana J Phys 2003, 61(5), 1009-13.

The mass of the dibaryon having spin, parity J^π = 0⁺, isopin I = 0 and strangeness -2 is computed using chiral color dielectric model. The bare wave function is constructed as a product of two color-singlet three-quark clusters and then it is properly antisymmetrized by considering appropriate exchange operators for spin, flavor and color. Color magnetic energy due to gluon exchange, meson self energy and energy correction due to center of mass motion are computed. The calculation shows that the mass of the particle is 80 to 160 MeV less than twice A mass.

1 table, 15 ref

002292   Perdrisat C F;Punjabi V (NO, College of William and Mary, Williamsburg, VA 23187, USA) : The JLab polarization transfer measurements of proton elastic form factor. Pramana J Phys 2003, 61(5), 827-35.

The ratio of the electric and magnetic proton form factors, G_Ep/G_Mp, has been obtained in two Hall A experiments, from measurements of the longitudinal and transverse polarizations of the recoil proton, P_l and P_t, in the elastic scattering of polarized electrons, e^→p → ep^→. Together these experiments cover the Q² range of 0.5 to 5.6 GeV². A new experiment is currently being prepared, to extend the Q² range to 9 GeV² in Hall C.

5 illus, 43 ref

002291   Pathak P P;Vijay Kumar;Vats R P (Physics Dep, Gurukula Kangri University, Haridwar-249 404) : Harmful electromagnetic environment near transmission tower. Indian J Radio Space Phys 2003, 32(4), 238-41.

The penetration of RF and microwave electromagnetic fields into human body and its possible consequences are studied. Earlier observations are theoretically verified which show that the radiation from high power transmission tower is more harmful to the people living nearby as compared to that from the low power transmission tower. Absorption of electric component of electromagentic radiation falling on the body, which increases with frequency, may result into temperature rise in the body. However, the magnetic induction, being very weak in comparison to the earth's magnetic field, is expected to have no effect on the human body.

1 illus, 6 tables, 5 ref

002290   Patel R P;Singh R P;Singh A K;Gwal A K;Hamar D (Atmospheric Research Lab, Physics Dep, Banaras Hindu University, Varanasi-221 005) : Observation of very low frequency emissions at Indian Antarctic station, Maitri. Pramana J Phys 2003, 61(4), 773-8.

Successes in recording VLF emissions at the Indian Antarctic station, Maitri (geom. lat. 62°S, geom. long. 57.23°E, L = 4.5) using a T-type antenna, pre/main amplifiers and digital audio tape recorder. VLF hiss in the frequency ranges 11-13 kHz and 13-14.5 kHz and some riser-type emissions in the frequency range 3-5 kHz and magnetospheric lines at about 6.2, 8.0 and 9.2 kHz are reported for the first time. The generation and propagation mechanism of these emissions are discussed briefly.

2 illus, 27 ref

002289   Patel P M;Joshipura K N (NO, V.P. & R.P.Y.P. Science College, Vallabh Vidyanagar-388 120) : Differential and integral cross-sections of e-O₂, O₃, NO, CO scattering at energies 100-1000 eV. Pramana J Phys 2003, 61(4), 685-92.

A modified additivity rule is formulated to calculate the differential cross-sections for elastic scattering of electrons from molecules. It improves the results at small angles and at relatively lower incident energies (<60>1000 eV). Integral cross-sections calculated presently are combined with the known total ionization cross-sections to obtain total (complete) cross-sections. An extension of the present approximation to larger molecules is also suggested.

6 illus, 2 tables, 19 ref

002288   Patel M;Patel S G;Vaidya R;Oza A T (Physics Dep, Sardar Patel University, Vallabh Vidyanagar-388 120) : Infrared spectrum of charge transfer complex of tetramethylbenzidine. Indian J Phys-Pt B 2003, (NULL), 207-13.

The infrared spectra of six charge transfer (CT) complexes of N, N, N', N' - tetramethylbenzidine were obtained after the preparation of these complexes. Various organic acceptors like chloranil, tetracyanoethylene, tetracyanoquinodimethane, tetranitro-9-flourenone, dichloro-dicyano-p-benzoquinone and iodine were used. It has been found that the complexes are semiconducting with either direct or indirect band gap lying in the infrared range. Electronic Gaussian profiles are also found in which electronic motions are strongly coupled with intramolecular vibrations.

5 illus, 6 tables, 21 ref

002287   Pasupathy J (Centre for Theoretical Studies, Indian Institute of Science, Bangalore-560 012) : Anomalies, symmetries and strangeness content of the proton. Pramana J Phys 2003, 61(5), 943-7.

The matrix elements of the operators of strange quark fields sΓs where Γ is 1 or y_μy⁵ between a proton state is calculated. The sigma term is found to be ≈41 MeV and the SU(3) singlet axial matrix element is found to be ≈0.22, both in agreement with experiment. The sigma term is found using the trace anomaly, while the determination of the axial vector current matrix element is from QCD sum rules. These correspond to (p<124>2s^-s<124>p)/(p<124>u< ^>-u+d^-d<124>p) ≈0.12 and for the axial current Δs ≈ -0.12, respectively. The role of the anomalies in maintaining flavor symmetry in the presence of substantial differences in quark masses is pointed out. This suggests that there is no need to invoke an intrinsic strange quark component in the proton wave function.

14 ref

002286   Parhil N;Rout G C;Behera S N (P G Department of Physics dep, M P C College (Autonomous), Baripada-757 001) : Effect of static jahn-teller distortion on magnetism in the manganite system : La_1-xSr_xMnO₃. Indian J Phys-Pt A 2003, 77(6), 575-80.

The colossal magnetioresistance magnetoresistan ce manganite system is described by a simple Hamiltonian containing the hopping term arising out of the itinerant e_g electrons of Mn atom in presence of a static badn Jahn-Teller lattice disotortion and the external magnetic field in the same e_g band. The ferromagnetism originates due to the more localized core t_2g electrons. The itinerant e_g electrons are hybridized with the on-site t_2g electrons with a strong hybridization. The magnetization (m) and lattice strain (e) are considerably infulenced by the model parameters of the system : i.e. the t_2g level (d), hybridization (v), magnetic coupling (g₁), J-T coupling (g), external magnetic field (b) and the impurity concentration (x). In same situation the ferromagnetic metallic state is pushed to higher temperatures. The results are discussed.

5 illus, 18 ref

002285   Pandey R (Phys Dep, Mohan Lal Sukhadia univ, Udaipur-313 001) : On the production of large-scale ionization irregularities in the equatorial F region. Bull pure appl Sci-Sect D 2003, 22(1), 27-33.

Production of large-scale ionization irregularities in the equatorial F region has been investigated by invoking the electric fields generated due to the gravity winds. It is found that such fields facilitate the production of ionizaton irregularities in the night time F region. The irregularities thus produced have been proposed to act as seed for the growth of plasma instabilities, namely, the Rayleigh-Taylor instability.

1 table, 29 ref

002284   Ojha M S;Rout G C;Behera S N (NO, S.C.S (Jr.) College, Puri-752 001) : A model study of gap equation in the heavy fermion superconductor. Indian J Phys-Pt A 2003, 77(6), 587-92.

The superconducting order parameter due to conduction electrons and the sub-lattice staggered field parameter due to the weakly delocalized F-electrons are calculated by Zubarev tyupe Green function method for the heavy fermikon magnetic superconductors. Solved the self-consistent mean field equations for the superconducting gap and the staggered field. The mutual influence on each other is studied by varying model parameters of the systems: the superconducting coupling (g₁, antiferromagnetic coupling (g₂, the hybridization (v) for various temperature ranges. The results show a strong correlation between them through the suppression and enhancement of the order parameters and transitgion temperatures as well as a few anomalous results. This model can explain the strong coupling between mangetism and superconductivity in the UM₂Al₃ and similar U-based systems.

3 illus, 16 ref

002283   Obada A S F;El-Shahat EL;Abdel-Aty M (Mathematics Dep, Faculty of Science, Al-Azhar University, Egypt) : Pseudo information entropy of a three-level atom interaction with two-laser fields in Λ-configuration. Pramana J Phys 2003, 61(4), 749-52.

Investigates some aspects of the pseudo entropy of multi-level system in the language of quantum information theory. The influence of the non-linear interaction and detuning parameter on the properties of the pseudo information entropy is examined.

2 illus, 7 ref