023659   Maheshwari B K;Sharma M L;Narayan J P (Earthq Engng Dep, Indian Inst of Technol Roorkee, Roorkee-247 667) : Structural damages on the coast of Tamil Nadu due to Tsunami caused by December 26, 2004 Sumatra Earthquake. ISET J Earthquake Technol 2005, 42(2-3), 63-78.

The December 26, 2004 Sumatra earthquake of Moment Magnitude M_w = 9.3, the largest earthquake in the world since the 1964 Prince William Sound, Alaska earthquake, generated a widespread tsunami. Soon after the earthquake, the authors visited Tamil Nadu and Pondicherry for a damage survey. Structural aspects of damages caused on the coast of Tamil Nadu has been described. The area covered was along the coast from Chennai on the east coast to Thiruvananthapuram on the west coast. There were practically no major evidences of damage due to direct shaking while damages due to tsunami were extensive. Both masonry and concrete structures were damaged, though level of damage varied. In general, structural damages involved: damage to brick masonry, damage to compound walls, collapse of adobe houses, failures of columns and toppling of roofs, damage due to lack of detailing of reinforcement. Causes of damages have been investigated and remedial measures to avoid those in a future tsunami are suggested. A good correlation between run-up height and level of damage is found.

22 illus, 4 tables, 12 ref

023658   Kumar P;Singh S K;Prasad D;Yadav S K;Singh J P;Singh K K;Mishra L K (Physcis Dep, Magadh Univ, Bodh-Gaya-824 234) : Theoretical study of resistive state of a thin superconductors and the behaviour of order parameter Delta and chemical potential Macron from TDGL (Time Dependent Ginzburg-Landau) equation. Acta Cienc Indica-Phys 2005, 31(3), 289-94.

On solving the free energy equation one gets solution of energy gap parameter Δ (n). Studied the behaviour of Δ and μn as a periodic function of x for the resistive states of a thin superconductors. The results are in good agreement with those of the earlier workers.

1 table, 20 ref

023657   Kumar D;Singh S K;Yadav S K;Jubeen S;Mishra L K (Physcis Dep, Magadh Univ, Bodh-Gaya-824 234) : Magnetic excitations and its dispersion and evaluation of radial dependence of the effective coupling J(R) of Nd ions in NdAl₂. Acta Cienc Indica-Phys 2005, 31(3), 295-301.

Radial dependence of effective coupling J(R) of Nd ions for NdAl2 has been determined. For lower value of R, J (R) is large and increases for R between 4 to 8 Angstrom becomes maximum and then decreases and finally attains a constant value. Such behaviour is in agreement with the experimental observation.

1 tables, 14 ref

023656   Krishnan A K;Rajamannan B (Phys Dep, Annamalai Univ, Annamalai Nagar-608 002) : Theoretical studies on binary mixture of edible oils with toluene using ultrasonic technique. Acta Cienc Indica-Phys 2005, 31(3), 319-20.

The ultrasonic velocity was evaluated theoretically using three different relations viz., Nomoto, free length theory (FLT) and impedance dependence relation (IDR) for edible oils like coconut oil, palm oil and castor oil with 0 toluene. These theoretical values are then compared with experimentally determined values. The assumption regarding the system being considered as a binary mixture.

2 illus, 6 ref

023655   Kanchan Mala;Singh N P;Mishra L K (Phys Dep, Magadh Univ, Bodh-Gaya-824 234) : An evaluation of collective excitations energy gap in the fractional quantum hall effect. Acta Cienc Indica-Phys 2005, 31(3), 383-6.

1 table, 11 ref

023654   Kanchan Mala;Singh N P;Mishra L K (Phys Dep, Magadh Univ, Bodh-Gaya-824 234) : An evaluation of magnetoplasmon excitations energy in filled landau levels in two dimensions. Acta Cienc Indica-Phys 2005, 31(3), 361-4.

The magneto plasmon energies energy has been measured for the filled Landau level in two dimension. The calculation has been performed in the Hartee-Fock approximation.

15 ref

023653   Jha S K;Ashok Kumar (Phys Dep, M.L.S.M. Coll, Darbhanga-846 004) : Transient radiation by a dipole antenna. Acta Cienc Indica-Phys 2005, 31(3), 303-6.

Calculates theoretically the radiation of transient electromagnetic waves by a thin straight dipole antenna excited by a transient current. The analysis is based on the approximation that the current pulse propagates along the antenna with low deformation. The theoretical results are compared with the numerical results available in the literature. They agree quite closely.

5 illus, 12 ref

023652   Ganguly P;Biswas J C;Lahiri S K (Integrat Optics Lab, Advd Technol Cent, Indian Institute of Technology, Kharagpur-721 302) : Effects of gamma irradiation on erbium indiffused lithium niobate substrate. J Optics 2005, 34(3), 145-52.

The effects of γ-radiation on Erbium (Er) doped LiNbO₃ subsrate are investigated by measuring the photoluminescence (PL) spectra at different radiation doses and by performing the x-ray diffraction (XRD) analysis before and after γ -irradiation. The PL spectra are found to change significantly withy-irradiation of dose 11.46 rod or above, γ-irradiation effects both the C-and L-bands of the erbium spectra. XRD study reveals that γ-ray exposure of dose 15.62 rod leads to morphological modification of the surface, with the appearance of a strong (101) Er₂O_} peak and a (104) LiNb0₃} peak along with the (006) and other peaks.

4 tables, 8 ref

023651   Durai S;Babu P (Postgrad and Res Dep of Phys, A.M. Jain Coll, Chennai-600 114) : Application of the modified three body force shell model to the study of the lattice dynamics of USb and UP. Acta Cienc Indica-Phys 2005, 31(3), 427-32.

Lattice dynamical properties of UP and USb have been studied using the modified three body force shell model. The model has been used in the study of lattice dynamics of Calcium oxide, Cesium Fluoride and Strontium oxide and is found suitable even in the uranium compounds which are more metallic in nature. The results are compared with the experimental or earlier theoretical findings whichever possible.

2 illus, 4 tables, 15 ref

023650   Dubey A P;Mishra P K;Sinha R (Phys Dep, B.N.M. Univ, Madhepura (Bihar)) : Excitation constants of the waves in dielectric tubes. Acta Cienc Indica-Phys 2005, 31(3), 311-18.

A theoretical study of excitation constants of the waves in dielectric tubes has been made. The equations for the calculation of the values of excitation constants of the waves of general character (HE_nm mode) in the three different regions have been set up. The variation of the excitation constants of HE_lm mode in three different regions of the tube, with the radius of the tube as well as thickness of the wall has been studied.

6 illus, 5 ref

023649   Bains B S (Phys Dep, Punjab Univ, Patiala-147 002) : Regge phenomenology and Pion-nucleon scattering at GeV energies. Acta Cienc Indica-Phys 2005, 31(3), 371-6.

Pion-nucleon scattering in the GeV region is studied using cyclic residue model based on Regge theory. Pion nucleon elastic differenial cross-sections have been calculated and are compared with the experimental data. It has been emphasized that Regge theory explains almost all the characteristics of the scattering data in the GeV region.

6 illus, 9 ref

022595   Yadav R K;Shanker R (Atom Phys Lab Dep of Phys, Banaras Hindu Univ, Varanasi-221 005, Email: rshanker@bhu.ac.in) : Relative backscattering yields for electrons and positrons from tungsten at keV energies. Indian J Phys 2006, 80(1), 43-8.

The backscattering coefficients (η^-₀, η⁺₀) and their ratios for impact of 8-28 keV electrons and positrons with a thick tungsten target at normal incidence, have been determined and compared with the available data on W and Au targets. It is found that the backscattering ratios attain a constant value of about 1.35 at higher impact energies while they are seen to rise significantly at the lower impact energies. The measurements of backscattering yields at three different scattering angles, namely, at θ = 110°, 120° and 130° for normal incidence of 8 keV electrons with a thick tungsten target, have been made. The measured relative yields are studied as a function of 6 and they are compared with the available data from other workers. The compared data are found to be in good agreement with each other and to follow a well known Lambert's cosine-law within the experimental uncertainty of measurements.

2 illus, 1 tables, 44 ref

022594   Yadav B S;Kumar N;Singh M K;Yadav M K (Molec Spectroscopy and Biophys Lab, D N (PG) Coll, Meerut-250 002) : FTIR absorption spectra and thermodynamic functions of 5-chloro-2,3-dihydroxy pyridine. Indian J Phys 2006, 80(1), 61-5.

The infrared absorption spectra of 5-chloro-2,3-dihydroxy pyridine have been recorded in the region 400 - 4000 cm^-1. The bands observed in the IR spectra are discussed by assuming the compound under C_s point group symmetry. The models of vibration for the different fundamentals have been proposed. The thermodynamic functions have also been calculated by using IR frequencies at different temperatures with the help of computer programming.

4 illus, 3 tables, 35 ref

022593   Ubale A U;Kulkarni D K (Dep of Phys, Govt. Vidarbha Inst of Sci and Humanities, Amravati-444 604) : Studies on size dependent properties of cadmium telluride thin films deposited by using successive ionic layer adsorption and reaction method. Indian J pure appl Phys 2006, 44(3), 254-9.

Successive ionic layer adsorption and reaction method (SILAR) have been used to deposit CdTe thin films onto glass substrate using cadmium chloride solution as cationic and sodium tellurite solution as anionic precursor. In order to study size dependent optical, structural and electrical properties, films having different thicknesses from 96 to 312 nm have been prepared by changing SILAR deposition cycles from 50 to 110. The XRD studies show that films were nanocrystaliine in nature with Wurtzite (hexagonal) structure. A shift of band gap energy from 1.86 to 1.47 eV, a decrease in electrical resistivity from 10.52 x 10^<1> to 4.78 x 10^<1> Ωm (at 528 K), increase in grain size from 14.5 to 32.8 nm and decrease in activation energy from 0.39 to 0.19 eV have been observed when film thickness was varied from 96 to 312 nm. The films prepared are semiconducting in nature with p-type conductivity.

7 illus, 2 tables, 24 ref

022592   Tyagi A K;Chavan S V;Purohit R D (Appl Chem Div, Bhabha Atom Res Cent, Mumbai-400 085, Email: aktyagi@magnum.barc.ernet.in) : Visit to the fascinating world of nano-ceramic powders via solution-combustion. Indian J pure appl Phys 2006, 44(2), 113-18.

Soft-chemical routes play an important role in preparation of nano-materials. In particular, the combustion synthesis has emerged as a promising solution-chemistry route for synthesizing a variety of oxide ceramics in the nano-crystalline form. The potential of this technique for preparation of a few oxide ceramics viz. yttria, barium polytitanates, barium and strontium thorate, strontium cerates powders has been presented. The role of process parameters in controlling the powder characteristics has also been established. These powders were characterized in terms of X-ray diffraction, surface area analysis, electron microscopy and sinterability. This process was shown to be simple and cost effective, which results in the phase pure, nano-crystalline powders having high surface area and better sinterability. These combustion-synthesized sinter-active powders achieved near the theoretical density, while retaining the fine grain microstructure.

2 illus, 1 table, 20 ref

022591   Tripathy K C;Sahu R;Mishra S (Dep of Phys, North Orissa Univ, Baripada-757 003, Email: rankasahu@rediffmail.com) : Microscopic study of low-lying collective bands in <. Pramana J Phys 2006, 66(2), 389-401.

The structure of the collective bands in ⁷⁷Kr is investigated within our deformed shell model (DSM) based on Hartree-Fock states. The different levels are classified into collective bands on the basis of their B(E2) values. The calculated K = 5/2⁺ ground band agrees reasonably well with the experiment. An attempt has been made to study the structure of the 3-quasiparticle band based on large J state in this nucleus. The calculated collective bands, the B(E2), and B(M) values are compared with available experimental data. The nature of alignments in the low-lying bands is also analyzed.

2 illus, 2 tables, 18 ref

022590   Tiwari R S;Mehta N;Agarwal P;Kumar A (Dep of Phys, Harcourt Butler Technol Inst, Kanpur-208 002 Department of Physics, DBS College, Kanpur-208 002, Uttar Pradesh, Email: dr_ashok_kumar@yahoo.com) : Investigation of antimony addition on the glass transition kinetics of Se₈₀Te_20-xSb_x using calorimetric measurements. Indian J Phys 2006, 80(1), 49-53.

Calorimetric measurements have been performed in glassy alloys Se₈₀Te₂₀ and Se₈₀Te_20-xSb_x (x = 0.5 and 1) to study the effect of the lower concentration of antimony additive on the kinetics of glass transition in glassy Se₈₀Te₂₀ alloy. The variation of T_g with heating rate and composition has also been studied. The heating rate dependence of T_g is used to evaluate the activation energy of glass transition. The thermal stability of these glasses has also been discussed. It has been found that thermal stability increases on addition of Sb in glassy Se₈₀Te₂₀ system. This increase is explained in terms of decrease in activation energy of glass transition.

8 illus, 2 tables, 23 ref

022589   Talati M;Jha P K (Dep of Phys Fac of Sci, M S Univ of Baroda, Vadodara-390 002) : Low frequency vibrational modes of nano-metric spherical viruses. Indian J pure appl Phys 2006, 44(2), 162-4.

The low frequency dynamics has been investigated by using an elastic body approximation for a spherical virus with free surface. The frequencies for spheroidal mode are obtained in terms of their eigen values. The effect of aqueous surrounding medium is also observed by incorporating the acoustic impedance factor. The damping time, frequency and quality factor are evaluated for a virus-medium system.

3 tables, 16 ref

022588   Somayajulu D R S;Patel N;Chawda M;Sarkar M; Sebastian K C (Dep of Phys Fac of Sci, M S Univ of Baroda, Vadodara-390 002) : Room temperature magnetism in Ge based bulk dilute magnetic semiconductors. Indian J pure appl Phys 2006, 44(2), 129-34.

Mossbaucr spectroscopy was used to study the hyperfine interactions in the Bulk Fe_0.008 Ge_0.992 system. The room temperature magnetism observed in the V and VI group donor impurity (As, Sb, Bi and Te) doped FeGe system is reviewed. Magneto-resistance and Hall effect measurements on these systems are discussed. The formation of Donor-Acceptor Pairs (DAP's) and carrier mediation seems to be the cause for this room temperature magnetic interactions in the Ge based bulk dilute magnetic semiconductors.

3 illus, 1 table, 24 ref

022587   Somanathan T;Pandurangan A;Subashini D; Sathiyamoorthy D (Dep of Chem, Anna Univ, Chennai-600 025, Email: pandurangan_a@yahoo.com) : Growth of single walled carbon nanotubes over Co-MCM-41 mesoporous molecular sieves. Indian J pure appl Phys 2006, 44(2), 173-6.

Highly ordered cobalt substituted MCM-41 mesoporous molecular sieves was synthesized by direct incorporation of cobalt into the MCM-41 framework through hydrothermal method. The calcined Co-MCM-41 was characterised by physico-chemical technique. The above-characterised material was tested for the application as catalytic template synthesizing single walled carbon nanotubes (SWCNTs) using acetylene as a carbon precursor by chemical vapour deposition (CVD) method in the temperature range 700-900 °C. The well graphitised CNTs in the pores of Co-MCM-41 was observed and confirmed by SEM and TEM. The good thermal stability and high productivity observed suggest that the mesoporous molecular sieves could be a promising catalytic template for synthesizing carbon nanotubes.

3 illus, 22 ref

022586   Sisodia A K;Bhasin V S;Kaushal R S (Dep of Phys and Astrophys, Univ of Delhi, Delhi-110 007, Email: rkaushal@physics.du.ac.in) : On diquark clustering in quark-gluon plasma. Pramana J Phys 2006, 66(2), 377-387.

The possibility that pairs of quarks will form diquark clusters in the regime above deconfinement transition for hadron matter at finite density is revisited. Presents the results on the diquark-diquark (dq-dq) interaction in the framework of constituent quark model taking account of spin, isospin and color degrees of freedom in the spirit of generalized Pauli principle. By constructing the appropriate spin and color states of the dq-dq clusters computes the expectation values of the interaction Hamiltonian involving pairwise quark-quark interaction. Finds that the effective interaction between two diquark clusters is quite sensitive to different configurations characterized by color and spin states, obtained after the coupling of two diquark states. The value of the coupling parameter for a particular color-spin state, i.e., {3, 1} is compared to the one obtained earlier by Donoghue and Sateesh, Phys. Rev. D38, 360 (1988) based on the effective φ⁴-theory. This new value of λ derived for different color-spin dq-dq states, may lead to several important implications in the studies of diquark star and diquark gas.

17 ref

022585   Singh V K;Khanna K N (Dep of Phys, VSSD Coll, Kanpur) : Thermodynamic properties of linear rigid tangent chains from Wertheim's thermodynamic perturbation theory. Indian J pure appl Phys 2006, 44(3), 248-53.

Wertheim's first order thermodynamic perturbation theory is employed to describe the distinct behaviour of fully flexible and linear rigid chains of varying chain lengths in solid phase. In particular, the solid phases of fully flexible and linear rigid chains of varying chain lengths are compared. Several thermodynamic properties such as fluid-solid co-existence boundaries of linear rigid molecules are greatly displaced towards lower densities with increasing chain length, the higher values of packing fractions for linear rigid chains in comparison to fully flexible chains to achieve the same chemical potential.

6 illus, 23 ref

022584   Singh N N;Patgiri M;Das M K (The Abdus Salam Int Cent for Theoretical Phys, , Strada Costiera 11, 31014 Trieste, Italy) : Discriminating neutrino mass models using Type-II see-saw formula. Pramana J Phys 2006, 66(2), 361-75.

An attempt has been made to discriminate theoretically the three possible patterns of neutrino mass models, viz., degenerate, inverted hierarchical and normal hier-achical models, within the framework of Type-II see-saw formula. Prom detailed numerical analysis we are able to arrive at a conclusion that the inverted hierarchical model with the same CP phase (referred to as Type [II A]), appears to be most favourable to survive in nature (and hence most stable), with the normal hierarchical model (Type [III]) and inverted hierarchical model with opposite CP phase (Type [IIB]), follow next. The degenerate models (Types [IA,IB,IC]) are found to be most unstable. The neutrino mass matrices which are obtained using the usual canonical see-saw formula (Type I), and which also give almost good predictions of neutrino masses and mixings consistent with the latest neutrino oscillation data, are re-examined in the presence of the left-handed Higgs triplet within the framework of non-canonical see-saw formula (Type II). Estimates a parameter (the so-called discriminator) which may represent the minimum degree of suppression of the extra term arising from the presence of left-handed Higgs triplet, so as to restore the good predictions on neutrino masses and mixings already acquired in Type-I see-saw model. The neutrino mass model is said to be favourable and hence stable when its canonical see-saw term dominates over the non-canonical (perturbative) term, and this condition is used here as a criterion for discriminating neutrino mass models.

5 tables, 40 ref

022583   Singh D;Singh S;Singh R P (NO, Indian Inst of Trop Meteorology, Dr. Homi Bhabha Road, Pune-411 008, Email: devendraasiingh@tropmet.res.in) : Thermal effects on parallel resonance energy of whistler mode wave. Pramana J Phys 2006, 66(2), 467-72.

Evaluates the effect of thermal velocity of the plasma particles on the energy of resonantly interacting energetic electrons with the propagating whistler mode waves as a function of wave frequency and L-value for the normal and disturbed magnetospheric conditions. During the disturbed conditions when the magnetosphere is depleted in electron density, the resonance energy of the electron enhances by an order of magnitude at higher latitudes, whereas the effect is small at low latitudes. An attempt is made to explain the enhanced wave activity observed during magnetic storm periods.

2 illus, 20 ref

022582   Shinde S;Pandya A;Jha P K (Dpartment of Phys Fac of Sci, M S Univ of Baroda, Vadodara-390 002) : Mechanical, elastic and anharmonic properties of Zn_1-xCr_xTe(0≤x≤l) diluted magnetic semiconductor. Indian J pure appl Phys 2006, 44(2), 148-51.

The mechanical, elastic and anharmonic properties of II -VI diluted magnetic semiconductor Zn_1-xCr_xTe (0≤x≤l) have been reported by using a phenomenological model based on the charge transfer effects due to the deformation of the electronic shell of overlapping ions. The obtained results on the elastic properties agree reasonably well with the available experimental data. The Debye temperature, third order elastic constants and the pressure derivatives of second order elastic-constants have also been reported. The decrease in Debye temperature with the increase in Cr concentration suggests that the lattice gets softened with the increase of Cr concentration.

3 tables, 21 ref

022581   Sharma T P;Patidar D;Sexena N S;Sharma K (Dep of Phys, Univ of Raj, Jaipur-302 004, Email: n_s_saxena@rediffmail.com) : Measurement of structural and optical bank gaps of Cd_1-xZn_xS (x = 4 and 6) nanomaterials. Indian J pure appl Phys 2006, 44(2), 125-8.

The sulphides of cadmium and zinc are widely used materials due to their suitable energy band gaps. Their energy band gap depends on the particle size. The materials have been prepared using a simple solution of CdCl₂ and ZnCl₂ mixed in proper ratio without use of thiophenol. Precipitate of CdZnS is obtained by passing H₂S, liberated from heated thiourea through this solution. It is confirmed by X-ray diffraction (XRD) and optical band gap estimation that materials prepared are nano-materials. The optical band gap of these materials has been determined in order to establish a relationship between energy band gap of bulk and nanomaterial. It has been noticed that optical band increases with the increase of Zn concentration in CdZnS.

6 illus, 1 table, 13 ref

022580   Sharma S;Sharma N D (Dep of Phys, Kurukshetra Univ, Kurukshetra-136 119, Email: sumanshano@yahoo.com) : Mossbauer, X-ray and magnetization studies of ZnAlFe_xO system. Indian J pure appl Phys 2006, 44(3), 220-6.

The structural and magnetic properties of the mixed spinel system ZnAl_xFe_2-xOv₄ (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been investigated by X-ray diffraction, SEM, EDAX, magnetization and Mossbauer measurements. The Mossbauer parameters, lattice parameters and crystalline size of the products formed with variation in the composition of Fe and Al ratio are studied. The studies confirm the formation of nano-size ferrite particles. It is observed that the lattice parameters and crystalline size decrease with increasing aluminium concentration. All the samples show super paramagnetic relaxation, except the samples (x=0.8, 1.0) which show super paramagnetic behaviour differentiated on the basis of magnetization. The decrease in area ratio with increase in Al concentration has been explained on the basis of ionic radius. The cationic distribution is calculated on the basis of Mossbauer and magnetization. These observations indicate the existence of a non-collinear structure in a nanoparticles ferrite system. The non-collinear structure in this system is also verified by Neel's two sublattice model.

1 illus, 2 tables, 31 ref

022579   Sharma R;Saxena N S;Kumar S;Sharma T P (Semicond and Polym Sci Lab Dep of Phys 5-6 Vigyan Bhawan, Univ of Raj, Jaipur 302 004, Email: n_s_saxena@rediffmail.com) : Optical band gap studies on Zn-Te pellets. Indian J pure appl Phys 2006, 44(2), 192-5.

Spectroscopic techniques are very useful for characterizing semiconducting and conducting materials. The optical properties (specially reflection spectra) of Zn_xTe_100-x (x=5, 10, 30 and 50) material in pellet form were studied. Polycrystalline semiconducting material has been prepared by Melt quenching method by taking pure Zn and pure Se in appropriate atomic weight ratio. The polycrystalline nature of Zn₅Te₉₅ was confirmed by XRD studies. In order to compare the studies on so prepared polycrystalline material and commercially obtained pure Zn₅₀Te₅₀ material, investigations were carried out on both types of samples. From the analysis of reflection spectra, energy band gaps of Zn_xTe_100-x material have been determined, which were found to increase from 1.67 to 2.31 eV. It is observed that the optical band gap of laboratory prepared Zn₅₀Te₅₀ material is in excellent agreement with that of commercially obtained pure Zn₅₀Te₅₀ material.

4 illus, 1 table, 12 ref

022578   Sharma A C (Phys Dep Fac of Sci, The M S Univ of Baroda, Vadodara-390 002) : Many particle aspects of a quantam wire. Indian J pure appl Phys 2006, 44(2), 98-106.

The electronic systems in one dimension have features quite distinct from those in higher dimensions. The one-dimensional Fermi surface consists of two discrete points, while in higher dimensions it is continuous. The low-energy particle-hole pairs' spectrum, which arises from momentum and energy conservations for wave vector between zero and twice of Fermi wave vector does not exist in one dimension. In higher dimensions, this region of missing states is filled in. The Fourier transform of one-dimensional Coulomb potential diverges. This led to wide spread belief that one-dimensional interacting electronic systems should exhibit non-Fermi liquid (known as Luttinger liquid) behaviour. However, there is still no unambiguous evidence both for the real existence or non-existence of Luttinger liquid behaviour in a realistic quantum wire. This talk briefly reviews key aspects of Fermi liquid approach and Tomonaga-Luttinger liquid approach for a one-dimensional system. Structure factor, pair distribution function and electron-electron scattering, which exhibit similarity between two approaches in low energy and momentum regime, is reviewed.

7 illus, 14 ref

022577   Shamsudeen R K;Nair S;Jayakumari V G (Nav Phys and Oceanographic Lab, Ministry of Def, Thrikkakkara, Cochin-682 021, Email: tsonpol@vsnl.com) : Equilibrium swelling, conductivity and electroactive characteristics of polyacrylamide hydrogels. Indian J Engng Mater Sci 2006, 13(1), 62-8.

Polyelectrolyte hydrogels are currently being studied extensively towards the realization of soft actuators. The conductivity, swelling behaviour and electroactive characteristics of partially hydrolysed polyacrylamide hydrogels, crosslinked to various extents are investigated. Conductivity studies have been made by means of dielectric relaxation spectroscopy both for hydrogels and dry gel powders over a wide range of frequency. The water dependent a.c. conductivity has been found to attain a plateau at higher frequencies whereas the a.c. conductivity of gel powders continued to increase as the frequency increases. The magnitude of the conductivity values is dependent on the extent of swelling for the hydrogels whereas it is dependent on the network structure for the gel powders. The electrical responses of hydrolysed polyacrylamide gels are also investigated and its correlation with hydration properties is also made. The on-off stimulation has been monitored by measuring the angular displacement of the hydrogels. A systematic analysis of the obtained results indicates that the electrical response and the water dependent conductivities of the gels have a direct correlation with the hydration properties.

7 illus, 26 ref

022576   Shah N A;Rather M F (Postgrad Dep of Electron & Instrumentation Technol, Univ of Kashmir, Srinagar-190 006, Email: farsgr@yahoo.com) : Realization of voltage-mode CCII-based allpass filter and its inverse version. Indian J pure appl Phys 2006, 44(3), 269-71.

A voltage-mode (VM) filter implementing first-order allpass (AP) function and its inverse signal is presented. The proposed circuit with one input and one output employs a single CCII, two resistors and one grounded capacitor. The circuit respectively implements allpass (AP) signal and its inverse function by using inverting CCII and non-inverting CCII without requiring change in the circuit topology. The phase angle is adjustable through frequency of the applied signal and/or grounded capacitor without disturbing the realizibility condition. The personal computer simulation program with integrated circuit emphasis (PSPICE) simulation results are included.

4 illus, 14 ref

022575   Sen P;Sen P K (Dep of Appl Phys, S G S Inst of Technol & Sci, 23, Park Road, Indore-452 003, Email: pratima_sen@hotmail.com) : Hyperfine splitting and quantum beats in CdSe quantum dots. Indian J pure appl Phys 2006, 44(2), 93-7.

The occurrence of quantum beat phenomena in CdSe quantum dots (QD) has been explained on the basis of hyperfine splitting of the excitons. The spin degeneracy of the conduction electrons is lifted by the magnetic field arising due to hole spin. The interaction of the coherent linearly polarized light with a quantum dot has been described by a V-type transition in which the two excited states are formed by the spin-split energies of the conduction band electrons while ground state is the hole state. The output radiation corresponding to each of the transitions will have polarization states characteristic of the <157>±l/2} -state of the electrons in the conduction band. Accordingly, in a time resolved measurement at a specific analyzer axis, the interference and consequent beating of the signal is expected to occur. The spin states of the excitons in a quantum dot have been analyzed using Dirac's relativistic wave equation. The results are found to be in good agreement with the reported experimental observations.

16 ref

022574   Savaroglu G;Aral E (Dep of Phys, Osmangazi Univ, 26480, Eskisehir, Turkey, Email: gsavarog@ogn.cdu.tr) : Excess isentropic compressibility and speed of sound of the ternary mixture 2-propanol + diethyl ether + n-hexane and the constituent binary mixtures at 298.15 K. Pramana J Phys 2006, 66(2), 435-46.

Speed of sound and densities of the ternary mixture 2-propanol + diethyl ether + n-hexane and also the binary mixtures 2-propanol + diethyl ether and 2-propanol + n-hexane have been measured at the entire composition range at 298.15 K. The excess isentropic compressibilities and the excess speed of the sound have been calculated from experimental densities and speed of sound. These excess properties of the binary mixtures were fitted to Redlich-Kister equation, while the Cibulka's equation was used to fit the values related to the values to the ternary system. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the binary mixtures and also the ternary mixtures. Speed of sound of the binary mixtures and the ternary mixture have been compared with calculated values from free length theory (FLT). collision factor theory (CFT), Nomoto's relation (NR), Van Deal's ideal mixing relation (IMR) and Junjie's relation (JR). The results are used to compare the relative merits of these theories and relations in terms of the root mean square deviation relative (RMSD_r).

3 illus, 5 tables, 23 ref

022573   Saraswat V K;Kishore V;Saxena N S;Sharma T P (Semicond & Polym Sci Lab 5-6 Vigyan Bhawan, Univ of Raj, Jaipur-302 004, Email: n_s_saxena@rediffmail.com) : I-V measurements of chalcogenide glass thin films. Indian J pure appl Phys 2006, 44(2), 196-200.

Measurements of I-V characteristics of Se_85-xTe₁₅Sb_x (where x = 2, 4, 6, 8 and 10) glassy thin films have been carried out at ambient conditions. These measurements have been taken using Keithley Electrometer/High Resistance Meter 6517A in its force voltage measure current (FVMI) mode. Measurements show that the film containing 4 at. wt. % of Sb allows the maximum current to pass through itself as compared to other counterparts of this series. The composition dependence of resistance has been explained on the basis of bond formation between Se and Sb at different compositions and hence Se₈₁Te₁₅Sb₄ composition could be termed as "critical composition" in the series under test as it is also strongly supported by dc electrical conductivity, thermal conductivity and thermal diffusivity measurements of these materials in bulk. Besides, the linear relationship between In (I) and V^1/2 confirm the conduction mechanism as to be Poole-Frenkel type.

4 illus, 1 table, 16 ref

022572   Rehani B R;Joshi P B;Lad K N;Pratap A (Dep of Metall Engng Fac of Technol & Engng, M S Univ of Baroda, Vadodara-390 001, Email: apratapmsu@yahoo.com) : Crystallite size estimation of elemental and composite silver nano powders using XRD principles. Indian J pure appl Phys 2006, 44(2), 157-61.

Studies on nanocrystalline materials require an accurate determination of crystallite size as well as the microstrains induced in the material. X-ray diffraction (XRD) and transmission electron microscopy (TEM) are the two well-known techniques for this purpose. Based on XRD principles, numerous approaches such as use of Scherrer equation, integral breath analysis, single-line approximation, Hall-Williamson method, etc have been developed for estimation of crystallite size. A systematic application of Hall-Williamson method for crystallite size estimation of high-energy milled elemental silver and silver-metal oxide (AgMeO) type composite powders and its comparison with Scherrer equation that does not take into account the peak broadening due to strain have been deals with. The effect of second phase particles on the crystallite size of silver matrix in AgMeO composite is also investigated.

2 illus, 2 tables, 16 ref

022571   Ray H (Dep of Phys, Indian Inst of Technol Roorkee, Roorkee-247 667, Email: hasi_ray@yahoo.com) : Coulomb-Born-Oppenheimer approximation in Ps-H scattering. Pramana J Phys 2006, 66(2), 415-22.

To improve the Coulomb-Born approximation (CBA) theory of ionization in positronium (Ps) and atom scattering, the effect of exchange is introduced. The nine-dimensional exchange amplitude for ionization of Ps in Ps-H scattering is reduced to a two-dimensional integral using the present Coulomb-Born-Opperiheimer approximation (CBOA). The methodology is extremely useful to evaluate ionization parameters for different target systems and for different types of ionization processes. It is then applied to evaluate the Ps-ionization cross-section and to estimate the effect of exchange on Ps-ionization in Ps-H system. Establishes the importance of exchange at lower energy region.

2 illus, 51 ref

022570   Rao P N;Rao D K;Veeraiah N (Dep of Phys, Acharya Nagarjuna Univ, Nagarjuna Nagar-522 510) : Influence of titanium ions on dielectric and other physical properties of AF-PbO-B₂O₃ glasses. Indian J Engng Mater Sci 2006, 13(1), 69-74.

Dielectric properties, viz., dielectric constant, ε, loss tan δ, a.c. conductivity, σ, in the frequency range 10²-10⁶ Hz and in the temperature range 30-300°C and the dielectric breakdown strength in air of AF-PbO-B₂O₃ (A = Li, Na, K) glasses containing different concentrations of TiO_<2> (in the range 0-0.6 mol %) have been investigated. Results have been analyzed in the light of different oxidation states of titanium ions in the glass matrix with the aid of data on optical absorption, ESR and IR spectral studies.

6 illus, 1 table, 25 ref

022569   Raj D;Kumar A (Dep of Phys, Ch. Charan Singh Univ, Meerut-250 004, Email: drdeoraj111@rediffmail.com) : Critical points in electron - Zn atom elastic scattering. Indian J Phys 2006, 80(1), 81-4.

Partial wave method along with a complex, energy dependent, local and central optical potential is employed to get the critical points for the electron - Zn atom elastic scattering. At critical points E_c = 486.3 eV and 81_c = 124.5°, the differential cross section attains a value of 4.488 x 10^-6 a²₀Sr^-1. About 80% spin polarization of scattered electron beam is obtained at angles 124.1° and 124.8° for the critical energy E_c.

1 table, 19 ref

022568   Prasad P B V;Shashikanth P B (NO, SR Res Lab for Stud in Crystallization Phenomena, 10-1-96, Mamillaguda, Khammam-507 001, Email: prasadpvb_kmm@rediffmail.com) : On imaging metal grains at high temperature: Laser light scattering microscopy. Indian J Engng Mater Sci 2006, 13(2), 162-6.

A simple device has been developed to meet the need of a base that is free from thermal expansion and is required in certain hot-stage microscopy studies. Further, images of sub-millimeter sized metal grains at high temperatures are noticed to under go vibration-like motion. In order to achieve stabilization of images, a unit called beam path cooler has been devised and its effect is examined.

5 illus, 17 ref

022567   Palit N;Dutta U;Chatterjee P (Energy Res Unit, Indian Ass for the Cultivation of Sci, Jadavpur, Kolkata-700 032, Email: parsathi_chatterjee@yahoo.co.in) : Detailed computer modeling of semiconductor devices. Indian J Phys 2006, 80(1), 11-35.

Detailed computer modeling to optimize the performance and design of semiconductor devices in general and of solar cells in particular has become extremely popular over the last two decades. This is because, experimentally, such optimization involves a huge number of trials; whereas the number of trials needed to optimize the performance of such semiconductor devices, can be decimated, using computer modeling, which is nowadays therefore widely recognized as a tool for faster progress of such research. A detailed computer model, as opposed to simple analytical models, is where the Poisson's equation and the electron- and hole-continuity equations are all solved from the first principles, without resorting to any simplifying assumptions. It is therefore, only such detailed models that are capable of giving an insight into device performance. Such models become very complicated in the case of disordered semiconductors, where we also have to take into account the trapping and recombination kinetics through the gap states. Moreover, in order to model both the electrical and optical properties of opto-electronic devices based on semiconductors in their entirety, we also need to combine the electrical model with a suitable optical model, capable of calculating not only the absorption in each portion of the device, but also the losses suffered by reflection or absorption in the non-active layers of the device. Moreover, diffused reflectance, transmittance and absorption when the device is deposited on a textured or rough surface also need to be taken into account; as also specular interference effects when the interfaces are flat. In this review, we will discuss a detailed electrical-optical model that is capable of modeling the performance of a general n-layer device based on crystalline, amorphous, poly-, micro- or nano-crystalline semiconductor, with particular reference to the modeling of opto-electronic devices, such as solar cells and color sensors.

8 illus, 2 tables, 94 ref

022566   Neogy S;Savalia R T;Tewari R;Srivastava D;Dey G K (Mater Sci Div, Bhabha Atom Res Cent, Mumbai-400 085) : Transmission electron microscopy of nanomaterials. Indian J pure appl Phys 2006, 44(2), 119-24.

Transmission electron microscope (TEM) has emerged as a very powerful tool for probing the structure of metals and alloys because of its capability to provide morphological information, crystallographic details, and chemical composition of phases distributed on a very fine scale in a given microstructure. Convergent beam electron diffraction, nano or micro beam diffraction and selected area diffraction techniques have been used to obtain crystallographic information whereas structural information is obtained by high-resolution electron microscopy (HREM). With its multifaceted capabilities such as nano-beam diffraction, composition analysis and imaging abilities at angstrom level, TEM has emerged as an instrument for complete characterization of nano scale microstructure of materials. The use of TEM in the study of various types of nanomaterials is described.

7 illus, 18 ref

022565   Mukherjee G K;Parihar N;Niranjan N;Manju G (NO, Indian Inst of Geomagnetism, Plot No. 5, Sector 18, New Panvel (W), Navi Mumbai-410 218, Email: gkm@iigs.iigm.res.in) : Signature of midnight temperature maximum (MTM) using OI 630 nm airglow. Indian J Radio Space Phys 2006, 35(1), 14-21.

An anomalous behaviour of F-region neutral temperature at night, sometimes exceeding the maximum afternoon values has been recorded at equatorial latitudes. This feature is referred to as Midnight Temperature Maximum (MTM)¹. The winds generated due to pressure bulge phenomena at the equator propagate polewards (northward) and its vertical component while propagating moves the F-region plasma downwards to a region of enhanced loss and airglow production. The optical signature of MTM phenomena (brightness wave) has been recorded at Kolhapur (16.8 °N, 74.2 °E, dip lat. 10.6 °N) in India using OI 630 nm night airglow during December 2002 to April 2003 showing peaks in intensity around 0200-0400 hrs LT. The structures were prominent for about two to three hours. The digital ionosonde data of Trivandrum (8.5 °N, 77.0 °E, dip <126>0.6 °S), Sriharikota (13.7 °N, 80.2 °E; dip <126> 10.5 °N) and Visakhapatnam (17.67 °N, 83.32 °E; dip <126> 20 °N) stations show the descent of the F-layer at all the low latitude stations during MTM disturbance. The meridional winds estimated from h'F data of Trivandrum and Sriharikota showed generation of poleward winds and time delay of about one-and-a-half hours was observed between the observed time of the descent of the layer (h'F) at Sriharikota and the time of observations of the signature of MTM phenomena at Kolhapur.

3 illus, 1 table, 26 ref

022564   Modi K B;Trivedi U N;Sharma P U;Lakhani V K; Chhantbar M C;Joshi H H (Dep of Phys, Saurashtra Univ, Rajkot-360 005) : Study of elastic properties of fine particle copper-zinc ferrites through infrared spectroscopy. Indian J pure appl Phys 2006, 44(2), 165-8.

The elastic moduli for fine particle Zn_xCu_1-xFe₂O₄ (x = 0.2, 0.4, 0.6 and 0.8) spinel ferrite system synthesized by wet-chemical technique have been determined through infrared spectroscopy and X-ray diffraction pattern analysis. The force constants for tetrahedral and octahedral sites determined through IR spectral analysis, lattice constant, X-ray density values through XRD pattern analysis; have been used to calculate elastic constants like bulk modulus. Young's modulus, rigidity modulus, Poisson's ratio and Debye temperature corrected to zero porosity. The elastic moduli values for all the compositions are found larger as compared to conventional ceramically prepared compositions. The results have been explained on the basis of elastic energy and grain size reduction effect of fine particle. The observed variation of elastic constants with zinc substitution have been interpreted in the light of strength of interatomic bonding.

1 illus, 2 tables, 9 ref

022563   Mishra A K;Milanarun M (Dep of Phys, Sabour Coll, Sabour, Bhagalpur-813 210) : Thermodynamic properties of liquid AIMg alloys. Indian J Phys 2006, 80(1), 55-9.

Statistical thermodynamic theory in conjunction with the complex formation model, has been used to investigate the thermodynamic properties of liquid AlMg alloys. Thermodynamic properties such as free energy of mixing, heat of mixing and entropy of mixing have been reproduced. Concentration-concentration fluctuations at the long-wavelength (S_cc(0)) limit have been obtained to investigate the stability and structural information about liquid AlMg alloys. The study of chemical short range order parameter (α₁) has been carried out to quantify the degree of order. The study reveals that liquid AlMg alloy is a weak interacting system. It is to mention that various factors such as size difference and electronegativity difference are too small to account for the asymmetric behaviour in this system. The observed asymmetry suggests that Al₃Mg2 complexes are formed in the liquid AlMg alloy.

3 illus, 1 tables, 31 ref

022562   Manocha L M;Valand J;Patel N;Warrier A; Manocha S (Deparment of Mater Sci, Sardar Patel Univ, Vallabh Vidyanagar-388 120, Email: manocha52@rediffmail.com) : Nanocomposites for structural applications. Indian J pure appl Phys 2006, 44(2), 135-42.

Nanocomposites comprise multiphase materials such as metals, polymers inorganic ceramics where at least one constituent phase has one dimension less than 100 nm. Different types of nanosize reinforcements, e.g. fiber, nanoclays, nanospheres, nanopowder etc amorphous or crystalline have been described along with fabrication processes and characteristics properties of different types of nanocomposites for structural applications.

6 illus, 2 tables, 34 ref

022561   Makwana R;Sharma A C (Phys Dep Fac of Sci, M S university of Baroda, Vadodara-390 002) : Two band model for a semiconductor quantum dot. Indian J pure appl Phys 2006, 44(2), 143-7.

Two band model for a semiconductor quantum dot has been developed. Energy eigenvalues and the wavefunctions have been calculated for the dot of radius, a. Calculation shows that energy eigenvalues which become discrete due to the quantum confinement depends on a. The band gap between two bands has been found a-dependent and it increases on decreasing the size of the dot. The calculated wavefunctions and energy eigenvalues are aimed to use for computing the size dependent static dielectric constant of the quantum dot. The computed wavefunctions and energy eigenvalues and preliminary calculations of dielectric constant are presented.

3 illus, 11 ref

022560   Kumar Sandeep;Sharma D R;Thakur N;Negi N S; Rangra V S (Dep of Phys, Himachal Pradesh Univ, Shimla-171 005) : Dielectric relaxation studies of binary mixture of pyridine and N, N-dimethylformamide in benzene solution using microwaves absorption data. Indian J pure appl Phys 2006, 44(3), 264-8.

The dielectric relaxation time (τ) of binary mixtures of different molar concentrations of pyridine (C₅, Hv₅ N) and N, N-dimethylformamide (DMF) in benzene solution has been calculated by using standard microwave techniques and Gopala Krishna's single frequency (9.875 GHz) concentration variational method at different temperatures (25, 30, 35 and 40°C). The solute-solute molecular associations have been proposed. The dielectric relaxation has been found to be an activated process. The energy parameters for this activated process have been calculated and compared with that of viscous flow process.

1 illus, 5 tables, 14 ref

022559   Kumar J;Sinha S K (Dep of Phys, L S Coll, B B A Bihar University, Muzaffarpur-842 001, Email: sk_sinha_phy@yahoo.co.in) : Semiclassical statistical mechanics of two dimensional hard-body fluid mixtures. Indian J Phys 2006, 80(1), 71-9.

The theory is developed to derive the thermodynamic properties of the two dimensional (2D) semiclassical hard convex body (HCB) fluid mixtures. Analytic expressions are given for the thermodynamic properties and virial coefficients for the 2D HCB fluid mixtures. The numerical results are discussed under the conditions : (i) σ⁰₁₁ = σ⁰₂₂and (ii) v₁ = v₂. The first order quantum corrections are also studied. The quantum effects depend on the conditions, shape parameters L₁₁ L₂₂ and concentrations x₁, x₂ in general, and increase with the increase of packing fraction η in particular.

2 illus, 4 tables, 15 ref

022558   Kher R S;Panigrahi A K;Dhoble S J;Khokhar M S K (Dep of Phys, Govt Autonomous Sci PG Coll, Bilaspur-495 006) : Mechanoluminescence of Gamma-irradiated salt. Indian J pure appl Phys 2006, 44(3), 227-9.

The dependence of mechanoluminescence (ML) intensity on <103>-dose of irradiated salt has been studied. It is found that initially the ML intensity increases with increasing <103>-dose given to the sample, attains an optimum value around 3 x 10^<3> Gy then decreases with further increase in <103>-dose. The spectroscopic study of ML and the effect of optical bleaching and storage (fading) on ML intensity have also been investigated to understand the mechanism of ML excitation in household salt. The radiation-induced changes in food material might also be analyzed by studying their ML properties.

2 illus, 12 ref

022557   Kamath S G (Dep of Math, Indian Inst of Technol Madras, Chennai-600 036, Email: kamath@iitm.ac.in) : The trace identity and the planar Casimir effect. Pramana J Phys 2006, 66(2), 325-44.

The familiar trace identity associated with the scale transformation x^μ → x'^μ = e^-λ x^μ on the Lagrangian density for a noninteracting massive real scalar field in 2 + 1 dimensions is shown to be violated on a single plate on which the Dirichlet boundary condition φ (t, x¹, x² = -a) = 0 is imposed. It is however respected in: (i) 1 + 1 dimensions in both free space and on a single plate on which the Dirichlet boundary condition ϑ(t,x¹ = -a) = 0 holds and (ii) in 2 + 1 dimensions in free space, i.e. the unconstrained configuration. On the plate where ϑ (t, x¹, x² = -a) = 0, the modified trace identity is shown to be anomalous with a numerical coefficient for the anomalous term equal to the canonical scale dimension, viz. 1/2. The technique of Bordag et al [Ann. Phys. (N.Y.), 165', 162 (1985)] is used to incorporate the said boundary condition into the generating functional for the connected Green's functions.

12 ref