005516   Mishra A;Jha L;Mishra S (Univ Dep of Phys, L N Mithila Univ, Darbhanga) : Fractional calculus in the solutions of multipole electric potential. Indian J Theor Phys 2004, 52(4), 287-93.

The application of fractional calculus in the solutions of electro-magnetic problem has attracted a number of scientists working in the field of wave propagations audits applications. Authors has used the fractional differ-integrals for the solutions of the problems of multipole expansion of potentials and Fields due to distribution of charge on spherical surface and for the fractional solutions of the standard scalar Helmholtz equation.

12 ref

005515   Majumdar T K;Ghosh K (Atapur Kenaram High Sch, , Atapur, North-24 parganas, W.B.) : Torsional oscillation set up in a semi-infinite orthotropic circular cylinder. Indian J Theor Phys 2004, 52(2), 151-60.

In this problem, the torsional vibraion of a semi-infinite circular cylinder consisting of orthotropic material by the application of different types of twist applied on one end of the cylinder has been considered. Two cases have been discussed and numerical values have been evaluated to show the distribution of displacement.

2 illus, 4 ref

005514   Madhurima V (Sch of Phys, Univ of Hyderabad, Hyderabad-500 046) : Dielectric and conformational studies of methanol ketone systems. Indian J pure appl Phys 2005, 43(7), 550-5.

Semi-empirical conformational analysis of five methanol + ketone systems with a systematic study with the variation of the hydrogen bond angle have been studied. The results of the conformational analysis are compared with experimentally determined dipole moments of the five systems. The ketones chosen for the study are acetone, 2-butanone, pentanone, cyclohexanone and acetophenone. Conformation analysis is done using the PM3 semi-empirical Hamiltoman and the dipole moments are determined using dielectric relaxation studies at microwave X-band frequency (9.97 GHz). Further confirmation with previous ¹³C NMR chemical shift data is also sought.

5 illus, 3 tables, 20 ref

005513   Lo pez Bonilla J;Morales J;Ovando G (Seccion de Estudios de Posgrado e Investigation, Escuela Superior de Ingenieria Mecania y Electrica Instituto Politecni, Edif.Z, 3er Piso, Col. Lindavista, C.P. 07738, Mexico, D.F., Email: lopezbil@hotmail.com) : Quaternions, 3-rotations and Lorentz transformations. Indian J Theor Phys 2004, 52(2), 91-6.

Exhibit how the rotations in three and four dimensions can be described through a complex matrix relation or equivalently by a quatermionic expression.

26 ref

005512   Lakshmanan M;Muruganandam P (Cent for Nonlinear Dynamics Dep of Phys, Bharathidasan Univ, Tiruchirapalli-620 024) : Nonlinear Schrodinger (NLS) family of equations: spatiotemporal patterns. Proc Indian Natn Sci Acad-Pt A 2005, 71(1-2), 59-74.

Nonlinear Schrodinger family of equations occurs in a variety of physical, chemical, engineering and biological problems of contemporary interest. These include problems ranging from the envelope dynamics of quasimonochromatic plane wave propagation in a weakly dispersive medium to Bose-Einstein condensates. It also describes the propagation of deep water waves as well as plasma waves and represents high intensity pulse propagation in optical fibers and photorefractive media. Further it possesses close connection with the dynamics of Heisenberg spin system. In the quantum mechanical context it is obtained in localizing the potential in the Hartree equation and in chemistry it appears as a model for mesoscopic molecular structures. The underlying systems possess fascinating spatiotemporal patterns starting from plane waves to solitary waves, bright and dark envelope solitons, exponentially localized dromions, algebraically decaying lumps, bound states, vortices, spiral waves, spatiotemporal chaos and so on. Different kinds of instabilities like Benjamin-Feir, Faraday, wave collapse, etc., giving rise to very many novel structures are also present. In particular, the cubic nonlinear Schrodinger equation is a completely integrable soliton possessing nonlinear dynamical system in (1+1) dimensions. However, in (2+1) dimensions the solution develops finite time singularities or blow up leading to wave collapse. Other types of nonlinearities such as power law, cubic-quintic, saturable and logarithmic are also of interest in different physical contexts. Wave collapse can be prevented by some of these modifications and ALSP by introducing suitable confining potentials as in the case of Bose-Einstein condensates or coupling with mean fields or by introducing higher order dispersion. Effects of dissipation, diffusion and external forcing leading to dissipative Gross-Pitaevskii and Ginzburg-Landau type equations show a large number of physically interesting spatiotemporal patterns. In addition the dynamical equations of motion of Heisenberg ferromagnetic spin systems with or without damping have also close connection with nonlinear Schrodinger family of equations. Give a brief review of this fascinating world of nonlinear Schrodinger family of equations.

12 illus, 32 ref

005511   Laha U (Dep of Phys, Natn Inst of Technol, Jamshedpur-831 014) : Energy values for light quark system in the ultra-relativistic limit. Indian J pure appl Phys 2005, 43(6), 469-70.

Schrodinger equation with relativistic kinematics for light quarks has been studied in the representation space for Harmonic oscillator potential. The eigen functions and eigen values so obtained may prove useful for deeper understanding of N-N interaction.

^ssc11 ref

005510   Kushwaha V S;Mehta N;Kumar A (Dep of Phys, Harcourt Butler Technological Inst, Kanpur-208 002) : High field conduction in amorphous thin films of Se₇₀Te_30-xCd_x in dark and in the presence of light. Indian J pure appl Phys 2005, 43(8), 630-5.

Glassy alloys of Se₇₀ Te_30-xCd_x (x = 2, 4, 6) are prepared by the quenching technique. Amorphous thin films of these alloys are prepared by the vacuum evaporation technique. Current-voltage (I-V) characteristics have been studied at various temperatures in the films in dark and in the presence of light. For this purpose, a dc voltage (0 - 300 V) was applied across the film I-Vcharacteristics show that, at low electric fields, an ohmic behaviour is observed. However, at high electric fields (E <126> 10₄ V/cm), the current becomes super ohmic. Analysis of the data shows the absence of space charge limited currents in amorphous Se₇₀Te_30-xCd_x thin films as In I/V versus V curves are not found to be straight lines with high correlation coefficient. Instead, In/versus V^1/2 curves are found to be straight lines having high correlation coefficient. The slope of these curves decreases with the increase in temperature. A more detailed analysis shows that the dominant mechanism of conduction is of Poole-Frenkel type in dark as well as in the presence of light.

6 illus, 1 table, 20 ref

005509   Kumar A;Sinha A K;Singh N P;Anzer A;Sinha A K;Verma P K;Mishra L K (Dep of Phys, Magadh Univ, Bodh-Gaya-824 234) : An evaluation of Landau parameters of nuclear matter using two nucleon - nucleon potentials. Acta Cienc Indica-Phys 2005, 31(2), 169-78.

Using Mishra and Tripathy Hamiltonian (Int. J. Mod. Phys. E. Vol. 3, 715 (1994)), we have evaluated the Landau parameter of nuclear matter using two nucleon-nucleon potentials. Our theoretical results are in good agreement with that of the earlier workers and with the experimental data.

005508   Khanna K M;Ekai R;Ronno C K;Rotich S K; Torongey P K (Phys Dep, Moi Univ, P O Box 1125, Eldoret, Kenya) : Theory of multilayer solar cells. Indian J pure appl Phys 2005, 43(6), 432-8.

An expression has been derived for the absorption coefficient of an incident radiation with energy hω by a semiconductor with band-gap ΔE₀. For a multilayer solar cell composed of seven layers that facilitate the solar cell to use the seven colours of the white light for maximum efficiency, the expression for the solar current I^sc has been used to calculate the value of the charge carrier density n in each layer. I_sc should be the same through all the layers for the layers to be connected in optical series. For such an arrangement, the efficiency of the multilayer solar cell turns out to be more than 42%.

1 illus, 1 table, 4 ref

005507   Kaushal R S (Dep of Phys & Astrophys, Univ of Delhi, Delhi-110 007) : The pendula in mathematical sciences. Indian J pure appl Phys 2005, 43(7), 479-88.

The role played by the pendulum and its variants in the development of mathematical sciences is reviewed. In particular, the case of a pendulum viz. harmonic oscillator in physics is highlighted in the context of mathematical, conceptual, conventional and engineering disciplines besides the one in mathematical physics. It is pointed out that in all these applications the concept of pendulum is used as a vehicle of knowledge mainly on the basis of structural analogy. Finally, its role a an example of the consciousness-manifesting phenomenon discussed.

1 table, 25 ref

005506   Kalyana Raman S B;Arulmozhi K T;Uvarani R (Dep of Phys, Annamalai Univ, Annamalainagar-608 002) : On the use of an empirical term in the computation of ultrasonic velocities in binary liquid mixtures. Acta Cienc Indica-Phys 2005, 31(2), 157-68.

An attempt has been made to correlate the velocity of ultrasonic waves in a liquid with the characteristic parameters of the liquid. While doing so, an empirical term has been formulated by grouping the characteristic parameters of the liquid based on earlier theories of velocity of ultrasonic waves. It has been found that the formulated empirical term exhibited significantly high correlation with the velocity. Using linear regression analysis, the velocities of ultrasonic waves in binary liquid mixtures are computed, which agreed excellently well with experimentally measured velocities, than those predicted by other theories.

12 illus, 5 tables, 8 ref

005505   Kalita K;Jhingan A;Barua S;Das J J;Varughese T;Sugathan P;Madhavan N;Nath S;Verma S;Singh R (Dep of Phys & Astrophys, Delhi Univ, Delhi-110 007) : Development of a large area telescopic detector system for elastic and transfer reaction angular distribution measurements. Indian J pure appl Phys 2005, 43(8), 567-72.

A large area telescopic detector set-up (<68>E-E) has been developed for elastic scattering and transfer reaction measurements involving low intensity radioactive ion beam (RIB) at Nuclear Science Centre (NSC) New Delhi. The detector system consists of a transmission type gas ionization chamber (ΔE) with axial field geometry followed by E-two- two-dimensional position sensitive silicon detectors (2D-PSSD) placed side by side (50 mm x 50 mm each) for the residual-energy measurements. The gas ionization chamber (IC) gives the energy loss of the particles for Z-identification whereas the silicon detectors give their energy as well as the position. The responses of the IC with alpha and fission sources and of the entire detector system with ⁷Be beam are presented which demonstrate the overall performance.

6 illus, 16 ref

005504   Kalaivani T;S Kumar;Krishnan S (Dep of Phys, Annamalai Univ, Annamalainagar-608 002, Email: prof_krishnan@yahoo.com ) : Dielectric relaxation studies of ternary liquid mixtures of aniline and substituted anilines with acetonitrile in the microwave region. Indian J pure appl Phys 2005, 43(7), 542-4.

The molecular structure and molecular forces in liquids and solution in particular have been investigated by dielectric relaxation studies. The nature and strength of molecular interactions have been established as the main cause for the chemical behaviour of compounds. The dielectric behaviour of three amines and their mixtures (i) N-methyl aniline + acetonitrile (ii) aniline + acetonitrile (iii) N, N-dimethyl aniline + acetonitrile has been studied at microwave frequency 9.36 GHz at 303 K. Different dielectric quantities like dielectric constant (ε'), dielectric loss (ε"), static dielectric constant (ε_o) and dielectric constant at optical frequency (ε_∞) have been determined. The relaxation time (τ) has been calculated by both Higasi's method and Cole-Cole method. The molar free energy of activation (ΔF_τ) and (ΔF_η) has also been reported. The complex systems investigated show the maximum relaxation time values at 1:1 complex ratio by both Higasi's method and Cole-Cole plot method.

2 tables, 20 ref

005503   Joseph Arul Pragasam A;Selvakumar S;Madhavari J;Prem anand D;Sagayaraj P (Dep of Phys, Sathyabama Inst of Sci and Technol Deemed Univ, Chennai-600 119) : Effect of metallic substitution on the optical, mechanical and photoconducting properties of L-arginium diphosphate single crystal. Indian J pure appl Phys 2005, 43(6), 463-8.

L-argmium diphosphate (LADP) is one of the important analogs of LAP crystal. LADP has excellent optical, thermal and mechanical properties, which make it a potential candidate for photonics device fabrication. The work deals with the growth and characterization of metal (Cu²⁺ and Mg²⁺) substituted single crystals of LADP. The grown crystals are subjected to single crystal XRD, AAS, FTIR, DRS spectra and microhardness studies. Microhardness studies indicate that the presence of dopant has enhanced the hardness of the material. The photoconductivity study reveals the positive photoconducting nature of both pure and doped crystals.

8 illus, 2 tables, 19 ref

005502   Jalan S;Amritkar R E (Phys Res Laboratory, , Navrangpura, Ahmedabad-380 009) : Synchronized clusters in coupled map networks. Proc Indian Natn Sci Acad-Pt A 2005, 71(1-2), 113-20.

Coupled maps on different networks provide a simple model of extended nonlinear dynamical systems. They form patterns or synchronised clusters as they evolve with time. Though the formation and behaviour of these clusters depend on the nonlinear dynamical functions as well as the topology of the networks, there are several features of the dynamics that are independent of the functions as well as the networks. Its discusses some of these general aspects of cluster formation.

2 illus, 10 ref

005501   Gupte N;Jabeen Z (Dep of Phys, Indian Inst of Technol, Chennai-600 036) : Spatiotemporal intermittency and scaling laws in coupled map lattices. Proc Indian Natn Sci Acad-Pt A 2005, 71(1-2), 75-83.

Discusses the spatiotemporal intermittency (STI) seen in coupled map lattices (CML-s). Identifies the types of Intermittency seen in such a systems in the context of several specific CML-s. The Chate Manneville CML is a introduced and the on-going debate on the connection of the spatiotemporal intermittency seen in this model with the problem of Directed percolation is summarized. Also discusses the STI seen in the sine circle map model and its connection with the directed percolation problem, as well as the inhomogenous logistic map lattice which shows the novel phenomenon of spatial intermittency and other types of behaviour not seen in the other models. The connection of the bifurcation behaviour in this model with STI is touched upon. Concludes with a discussion of open problems.

6 illus, 4 tables, 27 ref

005500   Gupta R S;Sharma S K;Kher R S;Gupta S K (Dep of Phys, Govt P G Coll, Satna, M.P.) : Effect of pH of solvent on the lyoluminescent decay in saccharides. Acta Cienc Indica-Phys 2005, 31(2), 219-22.

The effect of pH of solvent on the lyoluminescence (LL) of saccharides indicates that initially the LL intensity increases with time, attain an optimum value and then it decreases exponenially. And the total LL intensity is nearly same for the pH range 49, maximum at pH=12. Thier emission spectra shifts to the blue region of the spectrum with an increase in alkalinity. Impossible explanation of the pH effect is proposed.

4 illus, 11 ref

005499   Gunasekaran S;Natarajan R K;Rathikha R; Syamala D (Post Grad and Res Dep of Phys, Pachaiyappa's Coll, Chennai-600 030) : Vibrational spectra and normal coordinate analysis of nalidixic acid. Indian J pure appl Phys 2005, 43(7), 503-8.

Nalidixic acid is one of the important anti-bacterial with molecular formula C₁₂H₁₂N₂O₃. Fourier transform infrared (FTIR) and Fourier transform Raman (FTR) spectra of nalidixic acid have been used for the molecular study. A detailed vibrational analysis has been made on the fundamental modes of vibration. A normal coordinate analysis (NCA) has been carried out for nalidixic acid following the Wilson's F-G matrix method assuming the ethyl and the methyl group as point masses. A set of potential constants has been evaluated using the method of kinetic constants on the basis of Cs point group symmetry. The evaluated potential constants have been compared with those of related molecules and are in the expected range to confirm the correctness of the assignments made. To check whether the chosen set of vibrational frequencies contribute maximum to the potential energy associated with the normal coordinates of the molecule potential energy distribution (FED) has been evaluated.

3 illus, 1 table, 8 ref

005498   Goradia S G (Gravity Res Inst Inc, , 3003 Royal Huntsman Courty, South Bend, IN 46637, USA) : Gravity and strong force : potentially linked by quantum wormholes. Indian J Theor Phys 2004, 52(2), 142-9.

If Newtonian gravitation is modified to use surface-to-surface separation between panicles, it can have the strength of nuclear force between nucleons. This may be justified by possible existence of quantum wormholes in particles. All gravitational interactions would be between coupled wormholes, emitting gravitation flux in proportion to particle size, allowing for the point-like treatment above. When the wormholes are 1 Plank length apart, the resultant force is 10⁴⁰ times the normal gravitational strength for nucleons. Additionally, the invisible quantum wormholes may form binary effects imparting wave properties to all particles.

3 illus, 10 ref

005497   Gibson M S M;Lawrence N (Dep of Phys, MEPCO Schlenk Engng Coll, Sivakasi, Virudhunagar-626 005, Email: manorenj@yahoo.com) : Hydrogen diffusion in Fe_0.5Ti_0.5 - Quantum isotope effect. Indian J pure appl Phys 2005, 43(7), 532-4.

A quantum mechanical theory has been used to workout the Quantum Isotope Effect (QIE) on activation energy of the intermetallic compound Fe_0.5 Ti_0.5. The QIE has been calculated with the assumption that the hydrogen isotopes move as ions which diffuse interstitially in the crystal potential computed with the screened Coulomb interaction between proton and host ions. The QIE arises from the quantum mechanical zero point energy associated with the confining potential at the saddle point in the interstitial channel. In Fe_0.5Ti_0.5 system, the inequality E_a,H<62>E_{a,^2H <62> Ea,^3H in activation energy is reversed. QIE values have been calculated for various pressures ranging from normal to 2.5 GPa. A remarkable agreement between theory and experiment is observed. The value of QIE slightly increases with pressure. In this compound, hydrogen prefers the octahedral position and diffuses by O - O jump mechanism.}

1 illus, 9 ref

005496   El-Arabi A M (Phys Dep Fac of Sci Qena, South Valley Univ, Egypt) : Gamma activity in some environmental samples in south Egypt. Indian J pure appl Phys 2005, 43(6), 422-6.

As a part of national survey to evaluate natural radioactivity in the environment, concentration levels of natural radioactivity have been analyzed from more than 108 environmental samples taken from Wodi Alloqi area, south Egypt. The distribution of naturally occurring radionuclides of ²²⁶Ra, ²³²Th and ⁴⁰K in the samples (soil, granite, grass and water) have been measured using a high purity germanium detector. The specific activities in these samples, having a radium equivalent activity of less than 370 Bq.kg^-1, when evaluated for radiological effects show that all samples meet the external gamma-ray dose limitation of 1.5 mSv.y^-1. The data is expected to serve as a baseline survey for primordial radionuclide concentrations in igneous and sediment of the area.

1 illus, 1 table, 21 ref

005495   El Batal F H;Abo Naf S M (Glass Res Dep, Natn Res Cent (NRC), Dokki, 12622 Cairo, Egypt) : Spectroscopic studies of gamma-irradiated transition metals-doped soda lime phosphate glass. Indian J pure appl Phys 2005, 43(8), 579-90.

Optical absorption spectra of 3d transition metals have been measured in soda-lime phosphate glass before and after successive gamma irradiation. In general, the transition metals exhibit the lower oxidation state or octahedral coordination in phosphate glass. The experimental optical spectra are related to the respective specific transition of each transition metal ion. Transition metal-doped phosphate glasses reveal varying response to the effect of successive gamma irradiation. The intensity and growth behaviour of the radiation-induced bands are seen to depend on the type of the 3d transition metal. The response of the doped-phosphate glass to gamma rays irradiation is related to the formation of characteristic induced colour centers and the subsequent annihilation or approach of saturation.

4 illus, 3 tables, 90 ref

005494   Das K K (NO, , 34, Talbagan East Road, Nonachandanpukur, Barrackpore, Kolkata-700 122) : Study steady flow of viscous incompressible fluid through tubes of equilateral triangular cross-section. Indian J Theor Phys 2004, 52(2), 137-41.

The flow problem of incompressible fluid through tubes of different cross-sections have been discussed by various authors. But having cross-sections in the form of triangle is not common in flow problem and solution of these types of problem are not generally possible by ordinary integral transform method, a special care is to be maintained to minimize the extra parametric constrains; so, the co-ordinate system is to be choosen judicially, but in this paper attempt has been made to solve such type of problems by elementary Cartesian method by which the governing equation has been reduced to one in Laplacian form and the analytical solution of the problem has been deduced, the velocity distribution and the volume rate of flow have been deduced in most simplified form, the result has been also verified with those obtained by using trilinear method.

5 ref

005493   Chauhan D S;Sahai S (Dep of Math, Univ of Rajasthan, Jaipur-302 004) : Three-dimensional coupled-fluid flow over a highly permeable layer. Indian J Theor Phys 2004, 52(2), 107-8.

A three-dimensional coupled-fluid flow of a viscous incompressible fluid over a highly porous layer with an impermeable bottom is considered. A transverse sinusoidal suction velocity is introduced at the impermeable bottom. Expressions for the velocity field, co-efficient of skin-friction at the porous surface are obtained and the effects of various parameters on them are discussed.

3 illus, 19 ref

005492   Charan R V K (Dep of Phys, Gaya Coll, Gaya, Bihar) : Early detection and alarming of any crack in a railway track. Acta Cienc Indica-Phys 2005, 31(2), 145-8.

A theory alongwith a circuit is developed for early detection and alarming in case of any crack/breakage in a railway track, caused either by removal/loose contact of railway fish plate system or by any metallic aberration on the principle of phase cancellation and parallel resonance circuit attached to a mobile-radio-computer networking system.

2 illus, 3 ref

005491   Birajdar S V;Kadam C J;Shelke R M;Behere S H (Dep of Phys, S B Coll of Sci, Aurangabad-431 001, Email: subhashbehere@yahoo.com) : Potential function for diatomic molecules. Indian J pure appl Phys 2005, 43(6), 427-31.

The potential energy function suggested by Rafi (Indian J Phys, 74B (485) 2000) has been investigated further and the adjustable parameter c appearing in the potential function has been calculated. Using Varshni's formulation, the value of c has been calculated for fifty randomly selected diatomic molecules. Besides the individual value of c, an average value of c has also been used to calculate the potential energy curves for the ground states of CO and I2 molecules using this potential. These potential energy curves are compared with RKR and Morse curves.

2 illus, 1 table, 28 ref

005490   Bhattacharya S;Bhattacharjee J K (S N Bose Natn Cent for Basic Sci, , Sector-III, JD Block, Salt Lake, Kolkata-700 098) : Pattern formation in convection and reaction-diffusion systems. Proc Indian Natn Sci Acad-Pt A 2005, 71(1-2), 1-16.

Discuss in simple terms, the formation of certain often observed paterns in fluids in a reaction-diffusion systems.

7 tables, 28 ref

005489   Bhatnagar D;Bhardwaj V;Saini J S;Saxena V K; Sharma K B (Microwave Lab Dep of Phys, Univ of Rajasthan, Jaipur-302 004) : On radiations from switchable triangular microstrip antenna. J Instn Engrs-Pt ET 2005, 86(July), 9-15.

Paper describes theoretically the radiation properties of a switchable equilateral triangular microstrip antenna (ETMA) printed upon a typical ferrite substrate Ni_1.062Co_0.02Fe_1.948O₄ in the presence of normal dc magnetic bias field. The theoretical study is carried out in TM₁₀ and TM₁₁ modes of excitation by applying cavity model based modal expansion technique. Impedance characteristics of antenna and its far field radiation patterns are computed theoretically as a function of bias field strength. Large bandwidth and high frequency tunability of patch antennas printed on ferrite substrates make ferrite substrates a better choice in comparison to non-magnetic pure dielectric substrates for designing patch antennas.

11 illus, 1 table, 9 ref

005488   Bhandarkar V;Sen S;Muthe K P;Deshpande S K; Bhattacharya S;Gupta S K (Tech Physices and Prototype Engng Div, BARC, Mumbai-400 085, Email: drgupta@magnum.barc.ernet.in) : Detection of NO₂ by tellurium films. Asian J Phys 2005, 14(1-2), 97-101.

Tellurium films deposited on single crystal and polycrystalline Al₂O₃ and glass substrates were investigated for the detection of NO₂ gas. Films deposited on glass substrates were found to be most sensitive for use as NO₂ sensor. This was seen to arise from smaller grain size of films on these substrates. The detection mechanism was investigated using X-ray photoelectron spectroscopy and impedance spectroscopy.

5 illus, 1 table, 11 ref

005487   Bhandarkar V B;Katti V R;Manmeet Kaur;Gadkari S C;Gupta S K (Tech Phys and Prototype Engng Div, Bhabha Atom Res Cent, Mumbai-400 085, Email: gadkari@magnum.barc.ernet.in) : RF sputtered tungsten oxide films as NH₃ sensors. Asian J Phys 2005, 14(1-2), 11-15.

Thin films of tungsten oxide are prepared using RF sputtering technique and effect of platinum over layer on NH₃ detection has been studied. Atomic Force Microscopy showed that WO₃ films have sub-micron size grains. Further, it was found that the presence of fine Pt particles on WO₃ films enhances the sensitivity to NH₃ about ten times compared to pure WO₃. The results of X-ray photoelectron spectroscopy measurements suggest that the higher sensitivity could be attributed to an increased amount of chemisorbed oxygen on Pt particles in the WO₃:Pt film. Further, the sensors showed fast response .and recovery times of about 5 s and 10 s respectively.

10 illus, 21 ref

005486   Basu S;Hazra S K (Mater Sci Cent, Indian Inst of Technol, Kharagpur-721 302, Email: sb@matsc.iitkgp.ernet.in) : ZnO p-n homojunctions for hydrogen gas sensors at elevated temperature. Asian J Phys 2005, 14(1-2), 65-9.

ZnO p-n junctions were fabricated by adopting the techniques like D. C. Sputtering (for n-ZnO) and by modified CVD in reverse spray mode (for p-ZnO) respectively. Two different sensor structures like Pd/(p-ZnO)/(n-ZnO) & Pd/(n-ZnO)/(p-ZnO) were fabricated by depositing Pd on p-ZnO and on n-ZnO respectively using e-beam evaporation. The sensor studies at 300°C and 400°C using 500 ppm and 1000 ppm hydrogen in each case demonstrated that Pd on p-ZnO showed higher sensitivity while Pd on n-ZnO exhibited lower response time. The relatively high sensitivity & slower response time of the PoV(p-ZnO)/(n-ZnO) sensor structure could be explained from the porous nature of the CVD grown p-ZnO which increased the activity of Pd/(p-ZnO) interface during hydrogen adsorption and the involvement of both Pd/(p-ZnO) and (p-ZnO)/(n-ZnO) interfaces during current transport. In case of the other structure only Pd/(n-ZnQ) interface played the pivotal role in hydrogen sensing with much lower response time and ZnO n-p junctions became redundant during sensing mainly due to the compact nature of n-ZnO produced by D. C. Sputtering.

7 illus, 1 table, 14 ref

005485   Arivazhagan M;Krishnakumar V (Dep of Phys, J.J. Coll of Engng and Technol, Tiruchirappalli-620 009) : Normal coordinate analysis of 1-chloroisoquinoline and 2- methyl-8-nitroquinoline. Indian J pure appl Phys 2005, 43(8), 573-8.

The FTIR and FT-Raman spectra of 1-chloroisoquinoline and 2-methyl-8-nitroquinoline have been recorded in the region 4000-50 cm^-1 and 3500-50 cm^-1 respectively. The normal coordinate calculations were carried out using Wilson's FG Matrix mechanism on the basis of General Valence Force Field for both in-plane and out-of-plane vibrations. All the modes of vibrations are assigned and calculations of potential energy distributions are also performed.

4 illus, 2 tables, 15 ref

005484   Ansari I A;Singh K P;Shahabuddin M;Husain M; Gupta A (Low Temperature Laboratory Dep of Phys, Jamia Millia Islamia (Central University), Jamia Nagar, New Delhi-110 025, Email: intikhab@jamia-physics.net) : Computational interfacing of resistivity of high temperature superconductor using visual basic program. Indian J pure appl Phys 2005, 43(6), 439-45.

The developed Visual Basic interfacing program measured the transition temperature of any high temperature superconductor by using the IEEE 488.2 GPIB card. This interfacing program is also applicable for the doped superconductors. A summary of the work on the MgB₂ system is reported.

3 illus, 3 ref

005483   Ahmed Farag I S;Battisha I K;El-Rafaay M M (Natn Res Cent Solid St Dep, , Dokki, Cairo, Egypt) : Study of dielectric properties of α-alumina doped with MnO, CdO and MoO. Indian J pure appl Phys 2005, 43(6), 446-58.

The dielectric constant (ε), conductivity (σ) and activation energy (Eg) of α-alumina doped with different molar ratios ranging from 0.01 to 0.19 of manganese oxide (MnO), and from 0.01 to 0.16 for both molybdenum oxide (MoO) and cadmium oxide (CdO) were studied. The XRD patterns reveal clearly that the prepared samples, consist of only single phase (α-alumina phase). The crystallite size and micro-strain of the investigated samples were calculated. The crystallite size increases with increasing dopant concentration. But the rate of the crystallite growth differs from one system to another. The value of (ε) has been measured in a frequency range 42 Hz-5 MHz as a function of temperature ranging from 100 to 450°C. The possible explanations and the role of some impurities (mainly Mn, Mo and Cd) are analyzed. The value ε of pure sample increases from 9.4 to 10.63 as a function of temperature at constant frequency 1 MHz. In this material, the value of ε increases with increase of temperature due to space charge polarization and crystal defects, while it decreases as a function of frequency due to the scattering of charge carriers at high frequencies. From the plots of log a as a function of the reciprocal of temperature at different frequencies, it has been shown that more than one straight line with different shapes are obtained, indicating different conduction mechanisms at 100 kHz and 1 MHz. An increase in the conductivity with increasing dopant concentration appeared and it could be related to the increase of the charge carriers, which are localized at ions or vacant sites. The activation energies for conduction in the high temperature region are calculated and found to be equal to 0.489, 0.457 and 0.459 eV for 0.01% of Mn, Mo and Cd, cations respectively at constant frequency of 100 kHz. The lower activation energy values for conduction in doped materials may be attributed to a larger charge carrier concentration in them compared to pure α-alumina. The XRD was elucidating to confirm that the obtained phase is a single α-alumina phase.

11 illus, 1 table, 19 ref

005482   Ahmed A M (Phys Dep Fac of Sci, South Valley Univ, 82524 Sohag, Egypt) : Electrical conductivity and thermoelectric power of Ge₄₀Te₆₀ and Ge₃₈Sn₂Te₆₀ alloys. Indian J pure appl Phys 2005, 43(7), 535-41.

The dc conductivity and thermoelectric power (TEP) have been measured for the bulk binary alloy Ge₄₀Te₆₀ and ternary alloy Ge₃₈Sn₂Te₆₀. X-ray diffraction confirms that the samples are polycrystalline. The measurments were carried out in the temperature range 133<60>T<60>400 K. Variation of electrical conductivity with ambient temperature (T) proved the semiconductor behaviour for all range of T for both materials. With annealing time (t_an), the electrical conduction activation energy (E_σ) has been found to be with range from 0.1 1x10^-3 eV-63.3x10^-3 eV for Ge₄₀Te₆₀, and from 0.95x10^-3 to 52.93x10^-3 eV while the thermo-electric power activation energy (E_s) has been found to be in the range 2.28x10^-3 -39.3x10^-3 eV and 1.58x10^-3 -34.2x10^-3 eV for two alloys, respectively.

8 illus, 5 tables, 20 ref

005481   Ahmad Z (Dep of Phys Fac of Sci, Univ of Maiduguri, Borno State (Nigeria)) : Emission of the relativistic hadrons in the backward hemisphere in nuclear collisions. Acta Cienc Indica-Phys 2005, 31(2), 237-46.

The behaviour of the relativistic charged particle multiplicities and the pseudo-rapidity distributions for 4.5 A and 14.5 A GeV/c ²⁸Si-nucleus interactions are investigated in terms of the number of emitted relativistic hadrons in the backward hemisphere, n^b_s (relativistic charged particles emitted with space angle, θ_S, such that θ_S lie in the intervals 90° ≤ θ_S ≤ 278°). The η distribution of relativistic charged particles for the interactions with n^b_s≥ 1 are found to be fitted quite nicely by a single Gaussian distribution (GD), while it is fitted by two distinct CD's when the interactions are not accompanied by backward relativistic hadron. This in turn, suggest that in the production of event having n^b_s = 0 probably two different mechanisms operate.

7 illus, 3 tables, 19 ref

005480   Agrawal S;Bhatnagar D (Microwave Lab Dep of Phys, Univ of Rajasthan, Jaipur-302 004) : Dielectric study of binary mixtures of edible unsaturated oils. Indian J pure appl Phys 2005, 43(8), 624-9.

The dielectric and relaxation parameters of a binary system of edible oils, containing unsaturated fats namely mustard oil and coconut oil/ground nut oil/linseed oil in different proportions by volume are measured at different frequencies and a constant temperature (40°C). It is realized that at the given temperature, the dielectric constant of prepared samples at microwave frequency increases with increasing percentage of impurities. The dielectric loss at microwave frequency also increases with the increase in the amount of added impurity. However dielectric constant at optical frequency tends to decrease under similar conditions. The proposed technique to check the purity of samples at microwave frequencies is found better than the traditionally applied optical technique because here different dielectric parameters like dielectric constant (ε'), dielectric loss (ε") and dielectric relaxation in prepared samples may be determined at a time.

5 illus, 5 tables, 6 ref

005479    (Phys Dep, D.B.S. Coll, Kanpur-208 006) : QCD and electroweak effects in electron positron collision. Indian J Theor Phys 2004, 52(3), 237-49.

Estimate the value of the ratio R from 10 to 35 GeV. The value of R is likely to be affected by electroweak effects and quantum chromodynamic (QCD) correction up to third order in the frame work of Hoyer and Lund models.

3 tables, 31 ref

005478    (NO, , ) : On the flow of a particulate suspension in a circular tube under a pressure gradient equal to any function of time superposed on a steady poiseuille flow. Indian J Theor Phys 2004, 52(3), 227-36.

The problem of unsteady flow generated in a fluid-particle system due to pressure gradient equal to any function of time superposed on the initial steady Poiseuille flow has been discussed in this paper. The general results for the fluid and particle velocities, the volumetric flow rate and the wall shear stress are obtained. The flows of the suspension due to periodically impulsive and harmonically oscillating pressure gradients have been discussed in particular cases.

4 ref

005477    (Dep of Math, Univ of Rajasthan, Jaipur, Rajasthan) : Unsteady plane poiseuille flow and heat transfer in the presence of oscillatory temperature of the lower plate. Indian J Theor Phys 2004, 52(3), 215-26.

Investigates unsteady plane Poiseuille flow of an incompressible viscous fluid and heat transfer in the presence of oscillatory temperature of the lower plate and cross-flow velocity through the plates. The rate of injection of fluid through lower plate is equal to the rate of suction through upper plate in the presence of oscillating pressure gradient. The expressions of velocity and temperature distributions are derived, discussed numerically and presented through graphs. Also, the expressions of skin-friction co-efficient and the Nusselt number at both the plates are derived, discussed numerically and their numerical values for various values of physical parameters are presented through tables.

4 illus, 2 tables, 17 ref

005476    (Dep of Phys, government Polytechnic, Darbhanga-846 004) : Performance of the radiation pattern equation for the phyramidal horn antenna. Indian J Theor Phys 2004, 52(3), 207-13.

A new simplified expressions for the far-field radiation pattern equations for the pyramidal horn antenna are derived. The mathematical formulation given provides a comprehensive approach for the prediction of the far-field radiation pattern. The formulation can be modified and implemented with Mathcad for other types of aperture antennae. This formulae should be very useful for those involved in the analysis or design of horn antennae.

1 illus, 8 ref

005475    (Dep of Math, North Bengal Univ, P.O.-North Bengal University, Dist.-Darjeeling, West Bengal-734 430) : Approximate H-function for anisotropic scattering 1.B: Pomraning phase function. Indian J Theor Phys 2004, 52(3), 197-206.

Approximate forms of H-function already studied by have been extended to the case of anisotropically scattering atmosphere with phase function given by Pomraning.

9 ref

005474    (Dep of Math, Univ of Rajasthan, Jaipur-302 004) : Convection effects on the magnetohydrodynamic flow of Walters liquid B' through a channel bounded by a naturally permeable medium. Indian J Theor Phys 2004, 52(3), 185-96.

The combined effect of free and forced convection on the MHD flow of an electrically conducting Walters liquid B in a channel bounded by a naturally permeable lower wall of very small permeability is considered, with a temperature field taken as the sum of a linearly varying longitudinal part and an unknown transe distribution. The effects of various parameters are investigated on the velocity and temperature fields, induced magnetic field and electric field have been discussed.

4 illus, 10 ref

005473    (Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Ingenieria Mecanica y Electrica Instituto Politecn, Edif. Z, 3er Piso, Col. Lindavista, C.P. 07738) : Exact resolution of the Lorentz equation for constant electromagnetic field. Indian J Theor Phys 2004, 52(3), 179-83.

Using the exponential function of the Faraday matrix, author show that the Lorentz equation admits exact resolution for any homogeneous electromagnetic field.

15 ref

004412   Yadav R K;Mishra S K;Mishra V;Sunil Kumar (Phys Dep, D.B.S. Coll, Kanpur-208 012) : A note on convective dusty turbulence. Indian J Theor Phys 2005, 52(1), 19-30.

An early period decay equation for general type of turbulence by superiomposing a scalar field i.e. the temperature field on an incompressible velocity field has been derived. The equation thus obtained has been further simplified.

4 ref

004411   Unnikrishnan C S (Gravitation Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005) : On the gravitational deflection of light and particles. Curr Sci 2005, 88(7), 1155-9.

The gravitational deflection of light deduced from applying the equivalence principle is stated to be only half the general relativistic result. I show that the correct result is obtained entirely from applying the equivalence principle if the wave nature of light and particles is taken into account. This is equivalent to incorporating the gravitational redshift in the calculation. In Einstein's 1911 derivation, he used the wave aspect to get half the general relativistic value, but perhaps presumed that it was physically identical to the part that came from the application of the equivalence principle to the ray trajectory. Adding the two contributions together gives the correct general relativistic value for light and particles. For material particles, the 'particle' part dominates, and for relativistic quantum particles, the deflection approaches that for light.

2 illus, 5 ref

004410   Tomecek P;Filgasova M;Horakova V;Machackova A;Lapcik L (Phys and Mater Engng Dep, Tomas Bata University in Zlin, Nam. T.G.M 275, 762 72 Zlin, Czech Republic, Email: llapcik@ft.utb.cz) : Study of surface tension of HEC, CMC and MC water solutions. J Polym Mater 2005, 22(1), 81-5.

The influence of binary electrolytes (sodium floride, potassium bromide, lithium iodide), and different tenzides (sodium laurylsulphate, cetylpyridiumbromide) on the surface tension of cellulose solutions at constant temperature 25°C has been studied and the suitability of the systems for thin layer deposition on solid polymer surface with specific respect to utilisation of these compounds as a part of handling means of final arrangement has been testified. The cellulose ethers studied were two types of hydroxyethylcellulose, carboxymethyl cellulose and methylcellulose. The surface tension was determined by Wilhelm's tensometric method for sulutions. It has been found that generally a small addition of binary electrolytes slightly increases the surface tension, whereas the same amount of tensides remarkably decreases the same property of examined cellulose derivatives. Some self-organising ability of the studied cellulose derivatives has been recognised to form specific structures in the liquid surface connected with gaseous surroundings.

1 illus, 5 tables, 6 ref

004409   Suresh Kumar A;Manjubhashini A B (USIC, S V University, , Tirupati-517 502, Email: sureshusic@yahoo.com) : Spectral studies of Pr<. Indian J Phys 2005, 79(6), 597-600.

Pr³⁺ ions doped barium lead borophosphate glasses were prepared using 'Meltquenching technique, in the chemical composition of 3 BaO -15PbO -2 P₂O₅ - (80 - x) B₂O₃ - xPr₂O₃ (where x is 0.01, 0.02, 0.03, 0.04 and 0.05 mol%). Absorption spectra were recorded for these glasses in the UV-VIS- NIR regions and spectroscopic properties such as Racah( E¹, E², E³), spin orbit (ξ_4f)., configurational interaction (α and β) and Judd-Ofelt (Ω₂, Ω₄ and Ω₆) parameters were determined. The radiative lifetimes (τ_R) and branching ratios (β) for the fluorescent transitions were also evaluated for all these prasaeodymium glasses to understand their optical performance in present glasses.

2 illus, 6 tables, 22 ref

004408   Srivastava S K (Centre for Advanced Technologies, Haryana Engineering College, Jagadhri, Yamunanagar-135 003, Email: sanjeevsrivastava1980@rediffmail.com) : Relationship among thermal expansivity, isothermal bulk modulus and volume expansion ratio for ionic solids at high temperatures. Indian J Phys 2005, 79(6), 607-10.

New elementary relationship among A, K_T and (V_T/V₀) for ionic solids is reported. The solids considered are NaCl, KCl, MgO and CaO. The analysis is done at high temperatures with the help of the experimental data available. It is observed that α+ nK_T(V_T/V₀) not αK_T(V_T/V₀), remains invariant in high temperature domain for solids under study. Study also discloses that the Anderson-Gruneisen parameter increases with temperature in very high temperature domain. The results are valuable to understand the thermodynamic and thermoelastic properties of solids at high temperature.

4 illus, 4 tables, 12 ref

004407   Singh V K (Department of Physics, VSSD(PG) College, Kanpur-208 002, Email: singhvk_singhvk@yahoo.co.in) : Nonlinearity parameter, B/A, of pure liquids and binary liquid mixtures at elevated pressures. Indian J Phys 2005, 79(6), 611-17.

Nonlinearity parameter (B/A) has been evaluated for three pure liquids, namely: toluene, o-xylene, aniline and two binary mixtures, namely : toluene + o-xylene, toluene + aniline at elevated pressures at 303.15 K with the help of four different methods using the experimental data of ultrasonic velocity and density. A comparative study of the results obtained from different methods has been carried out in order to review different approaches in the light of molecular structure and intermolecular interactions.

5 tables, 27 ref