020276   Setlur G;Meera V (Physics Dep, Indian Institute of Technology, Guwahati, North Guwahati-781 039) : General approach to bosonization. Pramana J Phys 2007, 69(4), 639-50.

Summarizes recent developments in the field of higher dimensional bosonization made by Setlur and collaborators and propose a general formula for the field operator in terms of currents and densities in one dimension using a new ingredient known as a 'singular complex number'. Using this formalism, we compute the Green function of the homogeneous electron gas in one spatial dimension with short-range interaction leading to the Luttinger liquid and also with long-range interactions that lead to a Wigner crystal whose jnomentum distribution computed recently exhibits essential singularities. Ganeralizes the formalism to finite temperature by combining with the author's hydrodynarrfic approach. The one-particle Green function of this system with essential singularities cannot be easily computed using the traditional approach to bosonization which involves the introduction of momentum cutoffs, hence the more general approach of the present formalism is proposed as a suitable alternative.

16 ref

020275   Sengwa R J;Sankhla S (Dielectric Research Lab, Physics Dep, J N V University, Jodhpur-342 005, Email: rjsengwa@rediffmail.com) : Ionic conduction and dielectric dispersion study on chain dynamics of poly(vinyl pyrrolidone)-glycerol blends. Indian J pure appl Phys 2008, 46(7), 513-20.

Dielectric behaviour of glass-former polymer blends i.e. poly(vinyl pyrrolidone) (PVP) (average molecular weight Mw= 24000, 40000 and 360000 g mol^-1) with glycerol (Gly) up to 30 wt % PVP has been investigated in the frequency range 20 Hz-1 MHz at 25°C. The frequency dependent complex dielectric constant of the PVP-Gly blends indicates the relaxation process caused by the micro-Brownian chain motion of the PVP in the frequency range 10 kHz-1 MHz. The values of dielectric relaxation strength and relaxation time for this process were determined to explore the concentration and chain length effect on the relaxation process. The ac conductivity values were found corresponding to dc conductivity at frequencies lower than 10 kHz. The loss part of electric modulus exhibits a peak in the frequency range 10 kHz - 40 kHz, which corresponds to the ionic conductivity relaxation. The complex impedance plane plots of PVP-Gly blends confirm the contribution of the electrode surface polarization effect on the dielectric constant values at frequencies lower than 200 Hz. Further, the results of the dielectric dispersion of the PVP-Gly blends were compared with the dielectric dispersion of poly(vinyl pyrrolidone)-ethylene glycol oligomers (PVP-EGOs) blends [Shinyashiki et al., 2006] to confirm the effect of number of hydroxyl groups of the solvent molecules on the heterogeneous hydrogen bond complex formation in these blends.

020274   Saxena R;Shaktawat V;Jain N;Saxena N S;Sharma K;Sharma T P (Semiconductor and Polymer Science Lab, University of Rajasthan, Jaipur-302 004, Email: n_s_Saxena@rediffmail.com) : Structural and thermal characterization of metal halides doped polypyrrole. Indian J pure appl Phys 2008, 46(6), 414-6.

Polypyrrole and its metal halide composites have been synthesized by chemical oxidation polymerization technique with ammonium peroxisulphate (oxidant) in aqueous hydrochloric acid medium. structural characterization of polypyrrole samples S1 (100% Co), S2 (25%Ni -75%Co), S3 (50%Ni -50%Co), S4 (75%Ni - 25%Co) and S5 (100%Ni) has been made by XRD and FTIR spectroscopy. Thermal transport properties such as effective thermal conductivity (λ_e) and effective thermal diffusivity (χ_e) of these samples have been measured simultaneously at room temperature and normal pressure using transient plane source (TPS) technique. The values of effective thermal conductivity and effective thermal diffusivity are found higher in all the above-mentioned samples except sample S3 (50%Ni-50%Co). This result can be explained on the basis of bonding of cobalt and nickel with polypyrrole matrix during their polymerization.

020273   Satnoor S K;Vani R M;Konda R B;Mulgi S N; Hunagund P V (Department of PG Studies and Research in Applied Electronics, Gulbarga University, Gulbarga-585 106) : Design and development of inclined longitudinal slot rectangular waveguide antenna for LCP and RCP. Indian J Radio Space Phys 2008, 37(2), 135-8.

One, two and three pairs of inclined longitudinal slots located at the proper place with an appropriate angle on the broader wall of the rectangular waveguide antenna have been presented in this paper. The location of proper placement of slot and its appropriate angle is one where the antenna gives maximum radiation. The slots are placed from the centre of the broader wall leaving equal distance on either side of the rectangular waveguide with an inclination angle of 39ø with respect to centre axis to achieve good polarization pattern. These slots have been cut by electro-discharge machine (EDM) and antennas are designed using computer software AutoCAD 2000 for better precision. The experimental observations are carried out at designed frequency of 9.35 GHz, which gives left circular polarization (LCP). These antennas are also tested at below and above the designed frequency, i.e. at 9.3 and 9.4 GHz to study the polarization pattern and found to give right circular polarization (RCP) and LCP, respectively. It is also experimentally observed that these antennas are capable of producing left and right tilt in radiation pattern without deteriorating the impedance of the antenna. Since their VSWR values are well below the allowed value, i.e. <60> 2 for all the antennas, it implies better impedance matching. These antennas can find application in bistatic radar system of an aircraft. The design concepts of antenna are described and experimental results are discussed.

020272   Sarma A K;Ajit Kumar (Physics Dep, Indian Institute of Technol, Guwahati-781 039, Email: aksarma@iitg.ernet.in) : Perturbative effects on ultra-short soliton self-switching. Pramana J Phys 2007, 69(4), 575-87.

A numerical study of ultra-short self-soliton switching along with the corresponding analysis of coupler parameters is carried out for a Kerr coupler with intermodal dispersion. The influence of perturbations like third-order dispersion, self-steepening and intrapulse Raman scattering, on switching characteristics is also studied.

6 illus, 26 ref

020271   Saini R;Satsangi G S;Taneja A (School of Chemical Sciences, Chemistry Dep, St. John's College, Agra-282 002, Email: ataneja5@hotmail.com) : Concentrations of surface O₃, NO₂ and CO during winter seasons at a semi-arid region - Agra, India. Indian J Radio Space Phys 2008, 37(2), 121-30.

Surface measurements of O₃ (ozone) and its precursor gases such as NO₂ and CO have been made over an urban site of Agra (semi-arid region). Ozone and NO₂ show diurnal variations to an urban site during winter season. The overall increase of ozone is attributed to the increase in NO₂, CO and other precursor's emissions by different sources in the proximity of both the sites, i.e. St. John's College (SJC) and Dayalbagh. The average concentration of ozone was found to be 27.3 ppbv and it ranges from 1.2 to 69.0 ppbv, whereas the average concentration of NO₂ and CO were 66.3 ± 7.0 ppbv and 710.3 ± 159.4 ppbv, respectively. The coefficient of determination of regression curve between O₃ and NO₂ were γ = 0.50 at SJC and γ = 0.68 at Dayalbagh, whereas correlation between O₃ and CO were γ = 0.75 at SJC and γ = 0.50 at Dayalbagh, indicating positive correlation. Air samples from the two different locations of Agra city have indicated that the concentrations of ozone and CO were within the permissible limits but NO₂ concentration was above the limit.

020270   Saini D S;Bhooshan S V;Chakravarty T (Electronics and Communication Engineering Dep, Jaypee University of Information Technology, Waknaghat, Solan-173 215, Email: davinder.saini@juit.ac.in) : OVSF code groups and reduction in call blocking for WCDMA systems. Indian J Radio Space Phys 2008, 37(2), 143-7.

Compact code assignment (CCA) scheme for wideband CDMA (WCDMA) system has been proposed using Orthogonal Variable Spreading Factor (OVSF) channelization codes. In WCDMA systems, each User Equipment (UE) is given an OVSF code tree. In CCA scheme, the codes in OVSF code tree are divided into groups and the new call is handled by most congested group. The CCA scheme assigns code to the incoming call in the most compact form such that the available capacity after code assignment is least fragmented. This increases call handling capability of the OVSF-CDMA system. Simulation results show that proposed assignment scheme provide performance improvement in terms of reducing new call blocking probability.

020269   Sahoo S;Maharana L (Physics Dep, National Institute of Technology, Durgapur-713 209, Email: sukadevsahoo@yahoo.com) : Effect of Z'-mediated flavor-changing neutral currents on B→πK decay. Indian J pure appl Phys 2008, 46(5), 306-11.

Effect of a Z'-mediated flavor-changing neutral current (FCNC) on the B→πK decay process has been studied. Finds the branching ratio is enhanced from its standard model (SM) value and gives the possibility of new physics.

020268   Reddy R R;Rama Gopal K;Narasimhulu K;Sankara Reddy L S;Raghavendra Kumar K;Ahammed Y N;Vinoj V;Satheesh S K (Aerosol & Atmospheric Research Lab, Physics Dep, Sri Krishnadevaraya University, Anantapur-515 003) : Measurement of CO and SO₂ trace gases in southern India during ISRO-GBP Land Campaign - I. Indian J Radio Space Phys 2008, 37(3), 216-20.

Under ISRO-GBP land campaign-I, the concentrations of CO and SO₂ gases were simultaneously measured during 1-29 Feb. 2004 over southern India. These measurements were made onboard instrument vehicle along the road network during the dry, winter season of 2004. The study region covered coastal, industrial, urban, rural, remote, semi-arid and vegetated forest lands in the central part of the southern India. Average CO concentration at Nellore, an urban and coastal site is comparatively high (1300 ppbv) and the same is low (620 ppbv) at Sri Perumbuthur, a semi-urban site. These maximum levels of CO at Nellore may be due to traffic emissions and shallow surface layer. Average SO₂ concentrations at Sri Perumbuthur and Shadnagar (5 ppbv) are significantly higher than those at other locations. Fairly good correlation has been established between CO, SO₂ and meteorological parameters over the study region.

020267   Rawat M K;Sangeeta (Chemistry Dep, Agra College, Agra-282 002) : Ultrasonic study of molecular interactions and compressibility behaviour of strontium soaps in chloroform-propylene glycol mixture. Indian J pure appl Phys 2008, 46(3), 187-92.

Ultrasonic measurements of strontium soaps (caprate, laurate and myristate) have been carried out in a mixture of chloroform and propylene glycol (70%-30% v/v) to determine the critical micellar concentration (CMC), soap-solvent interaction and various acoustic parameters. The results show that ultrasonic velocity, intermolecular free length, adiabatic compressibility, adiabatic molar volume and apparent molar compressibility decrease while specific acoustic impedance, relative association and solvation number increase with increase in soap concentration. The results of ultrasonic measurements have also been explained in terms of well known equations.

020266   Randhir Singh;Kaushik B K;Quamara J K (Physics Dep, National Institute of Technology, Kurukshetra-136 119, Email: jkquamara@yahoo.com) : Investigation of thermally stimulated polarization current in polyetherimide. Indian J pure appl Phys 2008, 46(7), 491-6.

Thermally stimulated polarization currents (TSPC) have been investigated in polyetherimide (PEI) in the temperature region 10°-200°C under various polarizing fields, ranging from 12-176 kV/cm with different heating rates. The TSPC spectra show a pronounced peak (P₁) around 25°-30°C and a shoulder peak (P₂) in certain cases around 90°-110°C attributed to the dipolar nature of ether linkages and carbonyl groups (<62>C=O), respectively. A steady rise in current is observed beyond 120°C due to the dominance of large conduction currents. During successive cooling, the current retains its positive polarity and peak P₂ is observed around 110°C. The peak P₁ disappears during second TSPC cycle owing to the temperature dependence of saturation polarization, confirming the dipolar nature of this peak. In few cases the corresponding thermally stimulated depolarization current (TSDC) characteristics have also been recorded, which are found to consist of two peaks P₁ and P₂ located around 20° and 160°C, respectively. The peak P₁ is consistent with the TSPC peak observed around 25°-30°C whereas peak P'2 corresponds to αβ-relaxation. The thermal variation of dielectric constant of PEI has also been deduced from the TSPC spectra. The experimental observations are in general agreement with the theoretical predictions.

020265   Patra S (Physics Dep, College of Basic Sciences and Humanities, G B Pant University of Agriculture & Technology, Pantnagar-263 145, Email: Sarbeswar_patra2002@yahoo.com) : Effect of adatom-phonon interaction on parameters of single walled carbon nanotube. Indian J pure appl Phys 2008, 46(9), 651-6.

Double time Green function technique and Zubarev equation of motion approach have been employed. The modified dependence with <60>n_aσ<62> and chemisorption energy (ΔE) with radius of single walled carbon nanotube (SWCNT) was estimated. Consideres HF approximation to decouple higher order Green function and found that the inclusion of adatom-phonon interaction, change the surface parameters. The comparison of theoretical predication and experimentally observed value indicates to study in detail from the first principle.

020264   Patil L A;Mahanubhav M D (PG Department of Physics, Pratap College, Amalner-425 401, Email: lapresearch@rediffmail.com) : Synthesis of CdIn₂S₄ by flux method. Indian J pure appl Phys 2008, 46(5), 321-4.

Stoichiometric and non-stoichiometric powders of CdIn₂S₄ have been synthesized by flux method. X-ray diffraction (XRD) studies reveal that CdIn₂S₄ powders are polycrystalline in nature with spinel cubic structure. Thick films of CdIn₂S₄ powders have been prepared using screen printing technique on glass substrates. The films are characterized by energy dispersive X-ray analysis (EDAX) for quantitative elemental analysis, scanning electron microscopy (SEM) for microstructural studies and optical absorption studies for determination of band gap energies. The optical band gap energy for stoichiometric film is observed to be 2.38 eV while for nonstoichiometric films, it increases as the Cd/In ratio increases.

020263   Patil D R;Patil L A;Amalnerkar D P (Materials Research Lab, Pratap College, Amalner-425 401, Email: lapresearch@rediffmail.com) : Ethanol Gas sensing properties of Al₂O₃ O-doped ZnO thick film resistors. Bull Mater Sci 2007, 30(6), 553-9.

The characterization and ethanol gas sensing properties of pure and doped ZnO thick films were investigated. Thick films of pure zinc oxide were prepared by the screen printing technique. Pure zinc oxide was almost insensitive to ethanol. Thick films of Al₂O₃ (1 wt ) doped ZnO were observed to be highly sensitive to ethanol vapours at 300°C. Aluminium oxide grains dispersed around ZnO grains would result into the barrier height among the grains. Upon exposure of ethanol vapours, the barrier height would decrease greatly leading to drastic increase in conductance. It is reported that the surface misfits, calcination temperature and operating temperature can affect the microstructure and gas sensing performance of the sensor. The efforts are, therefore, made to create surface misfits by doping Al₂O₃ into zinc oxide and to study the sensing performance. The quick response and fast recovery are the main features of this sensor. The effects of microstructure and additive concentration on the gas response, selectivity, response time and recovery time of the sensor in the presence of ethanol vapours were studied and discussed.

12 illus, 22 ref

020262   Panwar O S;Khan M A;Dixit P N;Satyanarayana B S;Bhattacharyyat R;Sushil Kumar;Rauthan C M S (Plasma Processed Materials Group, National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110 012, Email: ospanwar@mail.nplindia.ernet.in) : Plasma diagnostic studies of S bend filtered cathodic vacuum arc system for the deposition of tetrahedral amorphous carbon films. Indian J pure appl Phys 2008, 46(4), 255-60.

Plasma parameters obtained using Langmuir probe of the vacuum arc generated in the outer region of an S bend filtered cathodic vacuum arc system developed for the deposition of tetrahedral amorphous carbon (ta-C) film and also hydrogen and nitrogen incorporated ta-C films have been reported. The effects of varying arc current and the magnetic field have been studied on the plasma parameters of the vacuum arc used in depositing ta-C, ta-C:H and ta-C:N films at different hydrogen and nitrogen partial pressures. The values of ion-saturation current (I_is), electron temperature (T_e) and electron density (n_e) are found to be in the range 1.50'10^-7-2.63x10^-6A, 1.90-2.29 eV and 3.6x10⁹-7.4x10¹⁰ cm^-3, respectively, of the vacuum arc generated for the deposition of as grown ta-C films. Hydrogen and nitrogen incorporation of the precursors are found to reduce the values of I_is, T_e and n_e of the arc generated. The presence of magnetic field is found to increase the values of I_is and ne and reduce those of T_e in depositing as grown ta-C films whereas hydrogen and nitrogen incorporation of the precursors decrease the values of I_is and n_e and enhances those of T_e. The properties of ta-C film so grown are also briefly summarized and found to have some novel features.

020261   Palani R;Jayachitra K (Physics Dep, D D E, Annamalai University, Annamalainagar-608 002) : Ultrasonic study of ternary electrolytic mixtures at 303, 308 and 313K. Indian J pure appl Phys 2008, 46(4), 251-4.

Ultrasonic velocity (U), viscosity (η) and density (ρ) of pottassium chloride (KCl), magnesium sulphate (MgSO₄) and mercury chloride (HgCl₂) mixtures have been measured at different molalities at 303, 308 and 313K. The derived acoustical parameters namely adiabatic compressibility (á), apparent molal compressibility (jK) apparent molal volume (ϕ_v), limiting apparent molal compressibility (ϕ_k⁰), limiting apparent molal volume (ϕ_v⁰), and their constants (S_k, S_v), viscosity B-coefficient and molal hydration number (H_n) have been computed from the experimental data. The variation in these parameters with respect to the molality of HgCl₂ has been explained on the basis of ion-solvent and structure making/breaking tendency of the electrolytes.

020260   Pagare G;Sanyal S P (NO, Government M L B Girls P G College, Bhopal, Email: gita_pagare@yahoo.co.in) : High pressure structural phase transition of three diluted magnetic semiconducting compounds. Indian J pure appl Phys 2008, 46(6), 410-3.

The high-pressure structural properties of three diluted magnetic semiconductor (DMS) compounds, viz Zn_1-xM_xSe (M=Cd, Fe and Mn) have been studied theoretically. The value of M-mole fraction x is given 0.16% for Fe, 0.1% for Cd and 0.24% for Mn. In order to investigate the high-pressure properties of these compounds, the two body potential approach has been used, which includes Coulomb term, short range repulsion and van der Waal interactions. It has been established that the potential used predict correctly the stability of zinc blende structure (ZBS) at ambient pressure. A good agreement between the experiment and the theoretical results has been achieved. The lattice parameter of all DMS ternary alloys obeys Vegards law very closely showing the linear dependence of lattice parameter on impurity composition. The 11.8, 9.3 and 9.2 GPa as phase transition pressure and 17%, 18.8% and 19% as percentage volume collapse for ZnFeSe, ZnMnSe and ZnCdSe alloys respectively, have been reported. This shows that these compounds get largely compressed during phase transition, though the % volume collapse overestimates the measured values. It has also been observed that the values of phase transition pressure for these alloys are less than their parent compound ZnSe (P_t= 14.4 GPa).

020259   Ojha P;Rakshit B;Pagare G;Sanyal S P (Physics Dep, Barkatullah University, Bhopal-462 026, Email: pooja_50123@rediffmail.com) : Electronic and structural properties of transition metal mono nitrides. Indian J pure appl Phys 2008, 46(6), 375-7.

The electronic and elastic properties of rock-salt structured nitrides, namely TiN and VN have been studied using ab-initio pseudopotential scheme and local density approximation. Both the compounds show metallic behaviour, with a large gap between occupied and unoccupied states. The mechanical and the elastic properties show excellent agreement with experimental results and well compared with other theoretical results because of the inclusion of partial core correction in the present calculation.

020258   Nimai Singh N;Rajkhowa M;Borah A (Physics Dep, Gauhati Univ, Guwahati-781 014) : Deviation from tri-bimaximal mixings through flavour twisters in inverted and normal hierarchical neutrino mass models. Pramana J Phys 2007, 69(4), 533-49.

Explore a novel possibility for lowering the solar mixing angle (θ₁₂) from tri-bimaximal mixings, without sacrificing the predictions of maximal atmospheric mixing angle (θ₂₃ = 45°) and zero reactor angle (θ₁₃ =0°) in the inverted and normal hierarchical neutrino mass models having 2-3 symmetry. This can be done through the identification of a flavour twister term in the texture of neutrino mass matrix and the variation of such term leads to lowering of solar mixing angle. For the observed ranges of Δm²₂₁ and Δm²₂₁ it calculate the predictions on tan² θ₁₂ = 0.5,0.45,0.35 for different input values of the parameters in the neutrino mass matrix. We also observe a possible transition from inverted hierarchical model having even CP parity (Type-IHA) to inverted hierarchical model having odd CP parity (Type-IHB) in the first two mass eigenvalues, when there is a change in input values of parameters in the same mass matrix. The present work differs from the conventional approaches for the deviations from tri-bimaximal mixing, where the 2-3 symmetry is broken, leading to θ₂₃ ≠ 45° and θ₁₃ <153> 0°.

4 illus, 3 tables, 28 ref

020257   Mulgi S N;Konda R B;Pushpanjali G M;Satnoor S K;Hunagund P V (PG Studies and Research in Applied Electronics Dep, Gulbarga University, Gulbarga-585106) : Design and development of wideband gap-coupled slot rectangular microstrip array antenna. Indian J Radio Space Phys 2008, 37(4), 291-5.

Novel design of four-element gap-coupled slot rectangular microstrip array antenna (FGSRMSA) is presented for broadband operation. The elements of antenna are fed using aperture coupled technique. From the experimental results it is seen that the antenna operates at single band of frequencies and shows broadside radiation characteristics. The overall impedance bandwidth is found to be 26.72%, which is 1.114 times more than that of four-element gap-coupled rectangular microstrip array antenna (FGRMSA). This shows the effect of slots in enhancing impedance bandwidth of FGSRMSA. The slots in FGSRMSA also improve the antenna input impedance and increase the gain by 20.8% when compared to FGRMSA. Details of antenna designs are described and experimental results are discussed.

020256   Mostashari S M;Moafi H F (Chemistry Dep, Faculty of Science, Gilan Univ, Rasht, Iran, Email: smmostashari@yahoo.com) : Effect of deposited ammonium bromide as flame-retardant on the flame-retardancy imparted to cotton fabric. Asian J Chem 2007, 19(2), 1181-6.

Effect of ammonium bromide as a nondurable finish on the flammability of 100% cotton fabric, (woven construction, weighing 160 g/m²) has been investigated. The laundered bone-dried, weighed fabrics were impregnated with suitable concentrations of aqueous ammonium bromide solutions by means of squeeze rolls and dried at 110°C for 0.5 h. Afterwards they were cooled in a desiccator, reweighed with an analytical precision and kept under ordinary conditions before the fulfillment of the vertical flame test. The optimum add-on values to impart flame retardancy expressed in anhydrous ammonium bromide per 100 fabric were aoout 6.64-7.81%. The results obtained follow the free radical theory.

1 table, 20 ref

020255   Mohan Reddy M;John K;Venkata Naidu S (Polymer science & Technology Dep, Srikrishna devaraya University, Anantapur-515 003) : Study of viscosity and refractive index of nylon 6,6 and poly(methyl methacrylate) in formic acid. Indian J pure appl Phys 2008, 46(3), 209-11.

Polymer blends of nylon 6,6 with poly methyl methacrylate(PMMA) have been prepared by solution blending and their miscibility has been investigated using physical techniques. Viscosity and refractive index for blend solutions at different percentages of the blend composition have been measured at 30°C. The results are discussed.

020254   Mishra R;Varma P;Tiwari M S (Physics Dep, Dr H S Gour Vishwavidyalaya, Sagar-470 003) : Transverse acceleration of ions in cusp: electrostatic ion-cyclotron instability with general loss-cone distribution as a possible source. Indian J pure appl Phys 2008, 46(7), 471-6.

Expressions for the dispersion relation, transverse and parallel energy of the resonant ions and growth rate of the Electrostatic Ion-Cyclotron Instability (EICI) are derived in the presence of the general loss-cone distribution function. The results are interpreted for the space plasma parameters appropriate to the auroral acceleration region. The results of the present study have shown that in the presence of the general loss-cone distribution the growth rate of the EICI enhances at lower perpendicular perturbations. The frequency of the EICI obtained is in accordance with the reported values. In the presence of the loss-cone distribution function, the transverse energy of resonant ions is also enhanced which may then give rise to the observed transverse acceleration of ions in the cusp region.

020253   Mehrotra I;Prakash S (Physics Dep, University of Allahabad-Allahabad 211 001, ) : Proton radioactivity with modified Coulomb potential. Indian J pure appl Phys 2008, 46(5), 312-4.

Phenomenon of proton decay is treated as the transmission of the proton across a potential barrier developed due to combined effects of the Coulomb potential, centrifugal potential and various renormalization processes. A microscopic approach has been used to calculate a Coulomb potential from Woods-Saxon charge density distribution function. Half-lives of proton emitters have been calculated in the framework of WKB method with modified Coulomb potential. Significant improvement in the values of half-lives is obtained as compared to those calculated with the Coulomb potential of a spherical charged core.

020252   Mawlong B (School of Physics, Hyderabad Univ, Hyderabad-500 046) : Charmless nonleptonic B decays into scalar and pseudoscalar mesons. Pramana J Phys 2007, 69(4), 521-31.

The charmless nonleptonic decay modes B → foK (π) involving a scalar and a pseudoscalar meson in the final state are studied. The scalar meson f_o is considered as a qq state, as favored by some recent studies. Using the generalized factorization approach, the branching ratios and CP violation parameters are computed for these modes. The form factors are calculated using the results from relativistic light front quark model and the ISGW2 model. It is found that the direct CP violation parameters in these modes are small. However, the obtained branching ratios are not in agreement with the experimental data. Therefore, these modes may be considered as possible probes for new physics.

3 illus, 21 ref

020251   Manoj Kumar;Kumar M (Physics Dep, G B Pant University of Agriculture and Technology, Pantnagar-263 145, Email: munish_dixit@yahoo.com) : Empirical high pressure equation of state for nano materials. Indian J pure appl Phys 2008, 46(6), 378-81.

An empirical high pressure equation of state is obtained by modifying the Shanker formulation, widely used in the literature to study the thermal properties of solids. The relation is used to study the compression behaviour of carbon nanotubes (bundle and individual tube). The results obtained are compared with the available experimental data. It is found that the relation obtained in the present work gives the results which are in the better agreement with the experimental data as compared with the earlier relation. The results are reported for bundle as well as for individual carbon nanotube.

020250   Manjul Kumar;Gajjar P N;Thakore B Y;Jani A R (Physics Dep, Sardar Patel University, Vallabh Vidyanagar-388 120, Email: manjulkumar@yahoo.com) : Electronic transport property of liquid Cd-Te alloys. Indian J pure appl Phys 2008, 46(6), 394-6.

The temperature dependent electrical resistivity of liquid Cd_0.6Te_0.4 alloys has been studied theoretically by employing Faber-Ziman formula. Also, the Faber-Ziman formulation is used to generate the partial structure factor of the liquid Cd_0.6Te_0.4 alloys at 1062°C. The electron-ion interaction is incorporated through a newly proposed local model potential alongwith Ichimaru-Utsumi (IU) dielectric screening function. Good agreement is achieved between the presently calculated results of resistivity with the experimental findings. Resistivity of liquid Cd_0.6Te_0.4 shows a semiconducting behaviour in the liquid phase. Thus, the resistivity data for Cd-Te system are in qualitative agreement with the nearly-free electron picture.

020249   Manickathai K;Kasi Viswanathan S;Alagar M (Physics Dep, Ayya Nadar Janaki Ammal College, Sivakasi-626 123) : Synthesis and characterization of CdO and CdS nanoparticles. Indian J pure appl Phys 2008, 46(8), 561-4.

Cadmium oxide and cadmium sulphide particles in the nanometer size regime have been synthesized using chemical routes. CdO nanoparticles are prepared by using ethylene glycol as a capping agent and CdS nanoparticles were prepared with H₂S gas. Variety of techniques like X-ray diffraction (XRD), UV-Vis absorption spectroscopy and Scanning Electron Microscopy (SEM) are used to carry out structural characterization of the nanoparticles. The optical band gap of these materials has been determined in order to establish a relationship between energy band gap of bulk and nanomaterials.

020248   Manhas P S;Sharma S;Pal K;Mangotra L K;Jamwal K K S (Physics and Electronics Dep, University of Jammu, Jammu-180 006) : High performance FGMOS-based low voltage current mirror. Indian J pure appl Phys 2008, 46(5), 355-8.

Current mirror (CM) is the basic building block in analog and mixed mode circuit design. For high performance analog circuit applications, the current transfer ratio, output impedance and output swing are the most important parameters to determine the performance of the current mirror. CM's are important for analog integrated circuits because of their wide use as constant sources or active loads in amplifier stages. Their application is increasing continuously due to the developments in current-mode integrated circuit design. This paper describes a new Current Mirror proposed and optimized to provide high accuracy, very high impedance and output swing at very low voltages using floating gate MOSFET's (FGMOS). The new mirror-High Performance Low Voltage Current Mirror (HPLVCM)- based on FGMOS has output current range of <16>2μA to 500μA, high output impedance (785.4GΩ at 100μA and 64M Ω at 500μA), comparatively high bandwidth (631MHz) and low input compliance voltage (0.18V at 50μA and 0.45V at 500μA input current). The new design has been verified using PSpice simulations for 0.5μm CMOS technology at a supply voltage of ±0.75V. The error in current transfer is observed to be less than ±0.1%.

020247   Kumar S R;Prajapati B;Tiwari S K;Tiwari V K (Applied Sciences & Humanities Dep, National Institute of Foundry & Forge Technology, Ranchi-834 003, Email: srkumar20052923@rediffmail.com) : Growth and characterization of copper, indium and copper-indium alloy films non-aqueous method of electrodeposition. Indian J pure appl Phys 2008, 46(3), 198-203.

New non-aqueous method for electrodeposition of copper, indium and copper indium alloy films, ethylene glycol has been used as the solvent which is non-toxic and non-hazard bath. All the source materials are readily soluble in this bath and they have higher working temperature (≥160°C). The copper films prepared in ethylene glycol based bath are preferred (111) oriented with grains well connected to each other indicates the epitaxial growth. The indium film has been observed in semi-molten state with intense (101) reflection. The Cu-In alloy film prepares at -1.1 V (Pt) is copper rich but the ratio tends to be1.0 in the bulk of the film. Multiphase deposits are observed with grains which are spherical and well connected to each other. The resistivity and carrier concentration of the as-deposited copper and copper indium alloy films are found to be 0.2 Ω-cm, 9.9x10¹⁵ per cm³ and 2.5 Ω-cm and 5.5x10¹⁷ per cm³, respectively. The as-deposited films are found to be resistive but the resistance decreases when the films are annealed at moderate temperature.

020246   Kumar R;Jayakumar S;Kannappan V (Physics Dep, The New College, Chennai-600 014, Email: jk_5454@yahoo.co.in) : Study of molecular interactions in binary liquid mixtures. Indian J pure appl Phys 2008, 46(3), 169-75.

Acoustical parameters for two binary liquid mixtures namely, acetone - carbon tetrachloride (CCl₄) and acetone - benzene have been determined at three different temperatures. The acoustical parameters such as the adiabatic compressibility k, the free length of interaction Lf, interaction parameter χ, Lennard Jones Potential (LJP) and also excess parameters such as excess velocity u^E, excess compressibility k^E, excess volume V_f^E and excess free length L_f^E are computed for the two systems at 303K, 308K and 313K from the measured ultrasonic velocity and density values. The extent of interactions existing between component molecules has been found out. In acetone - CCl₄ system, the interaction parameter values have been out to be negative suggesting the presence of weak dipole -induced dipole interactions in this system. However, in acetone - benzene system, there are strong dipole - induced dipole interactions. With increase in temperature, the extent of interaction becomes weak in both the systems due to thermal agitation of the component molecules.

020245   Kulhar V S (Physics Dep, University of Rajasthan, Jaipur-302 055) : Positronium formation in 2S-state in atomic hydrogen. Indian J pure appl Phys 2008, 46(4), 245-50.

Problem of positronium formation in its first excited state (2s) in positron-hydrogen collision has been investigated using a formulation based on three particle scattering. Second order matrix elements have been calculated taking 1s intermediate state of hydrogen atom into account. The effect of inclusion of second order terms is to raise the total cross-section results over Born results. The cross-section results have been compared with the results of calculations based on first Born, the two state approximation and convergent close coupling approach in the energy range 0.9-10 Ryd and with other available results in an energy range 30-2000 eV.

020244   Kukreti A;Ashok Kumar;Naithani U C (Physics Dep, Garhwal University, Pauri Campus , Pauri(Garhwal), Uttarakhand-246 001, Email: ashishkukreti07@gmail.com) : Electric field dependent microwave losses in Ba_xSr_1-xTiO₃ perovskites. Indian J pure appl Phys 2008, 46(8), 580-7.

The electric field dependent microwave loss of anharmonic Ba_xSr_1-xTiO₃ perovskites has been calculated in its para electric phase from the Silverman Joseph Hamiltonoian augumented with fourth order phonon co-ordinates using double time Greens functions. The results are used to obtain an expression for the frequency and temperature dependence of dielectric loss at microwave frequencies due to impurity and anharmonic scattering. The loss tangent consists of a contribution which is quadratic in applied biasing and field independent. The variation of tand with applied field is noticeable in the vicinity of Curie temperature . In the higher temperature region, the electric field effect ceases and the increase in loss arises mainly due to higher order anharmonic terms.

020243   Kukreti A;Ashok Kumar;Naithani U C (Physics Dep, Garhwal University, Campus pauri, Pauri (Garhwal), Uttarakhand-246 001) : Field dependent dielectric behaviour of Ba_xSr_1-xTiO₃ perovskites. Indian J pure appl Phys 2008, 46(4), 276-82.

Using the method of double time thermal Green's functions and Kubo formalism, a general expression has been derived for the electric field dependence of the complex dielectric constant of Ba_xSr_1-xTiO₃ ferroelectric crystal in the paraelectric phase from the Silverman-Joseph Hamiltonian augmented with fourth order phonon co-ordinates. The change of mass as well as harmonic force constant between impurity atom and host lattice atoms are taken into account. The frequency, temperature and electric field dependent dielectric constant of Ba_xSr_1-xTiO₃ crystal has been discussed. Dielectric constant increases with increase of applied field. The results are compared with previous experimental and theoretical results.

020242   Kher R S;Upadhyay A K;Dhoble S J;Khokhar M S K (Physics Dep, Government Science P G College, Bilaspur-495 006, Email: kherrs@hotmail.com ) : Luminescence studies of MgSO₄:Dy phosphors. Indian J pure appl Phys 2008, 46(9), 607-10.

The lyoluminescence (LL) in MgSO₄:Dy phosphors has been studied. Thermoluminescence (TL) and photoluminescence (PL) have also been studied to understand the mechanism of LL. MgSO₄ phosphors containing different concentrations of Dy (0.05-1.0 mole%) have been prepared by solid-state diffusion method. The maximum LL intensity is observed for 0.05 mole% of Dy in MgS_O4. TL glow curves of MgSO₄:Dy phosphors are complex and peaks around 110, 150 and 220°C are observed. The effect of post-irradiation annealing on the LL shows that with removal of 220°C TL peak, the LL intensity decreases markedly. LL and TL intensity of MgSO₄:Dy phosphors have also been recorded for different γ-doses. PL studies conducted on the sample show that Dy³⁺ ion acts as the luminescence center in MgSO₄ phosphor.

020241   Khan A;Sinha S;Panchadhyayee P (NO, Electrocom Corporation, P.O. Box 60317, Potomac, MD 20859, USA) : Density of states in an electrically biased quantum well. Pramana J Phys 2007, 69(4), 651-9.

Density of states in a quantum well has been studied in the presence of an electric field applied perpendicular to the growth direction. An extra quantization is introduced to the motion of the electron due to the discrete energy levels known as Wannier-Stark ladder states and the nature of density of electronic states changes from quasi two-dimensional to quasi one-dimensional.

4 illus, 13 ref

020240   Ketabi S A;Milani Moghaddam H;Shahtahmasebi N (School of Physics, Damghan University of Basic Sciences, Damghan, Iran) : Electron transport through SWNT/trans-PA/ SWNT structure (the role of solitons): A t-matrix technique. Pramana J Phys 2007, 69(4), 661-8.

Using a tight-binding model and a transfer-matrix technique, we numerically investigate the effects of the coupling strength and the role of solitons on the electronic transmission through a system in which trans-polyacetylene (trans-PA) molecule is sandwiched between two semi-infinite single-walled carbon nanotubes (SWNT). We rely on Landauer formalism as the basis for studying the conductance properties of this system. Our calculations show that the solitons play an important role in the response of this system causing a large enhancement in the conductance. Also our results suggest that the conductance is sensitive to the CNT/molecule coupling strength.

5 illus, 24 ref

020239   Kaushik S D;Singh A K;Srikala D;Patnaik S (School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110 067) : Cryogen-free low temperature and high magnetic field apparatus. Indian J pure appl Phys 2008, 46(5), 334-8.

Importance of low temperature and high magnetic field measurements in pure and applied science research cannot be overstated. Traditionally these experiments have been carried out by evaporation of liquefied helium. This is a costly proposition, especially in our country, where maintaining liquid helium plants and the recovery lines has become persistent predicament. In this paper, the possibility of an alternative cost-effective technology based on two stage Gifford-McMahon closed cycle cryocoolers which is most ideally suited for small groups of researchers has been presented. The principle of operation and instrumentation details of a recently installed single compressor 1.6 K, 8 tesla cryocooler has been described.

020238   Kaur N;Rajneesh Mohan;Gaur N K;Singh R K (Physics Dep, Indian Institute of Technology Delhi, New Delhi-110 016, Email: drnjkaur@rediffmail.com) : Specific heat studies of hexagonal manganites RMnO₃ (Y, Sc, Lu) at low temperature. Indian J pure appl Phys 2008, 46(6), 447-50.

The Rigid Ion Model (RIM) has been formulated by incorporating the effects of the long-range Coulomb attraction, the short-range Hafemeister-Flygare (HF) type overlap repulsion and van der Waals (vdW) interactions to investigate the temperature dependence of the specific heat of hexagonal manganites RMnO₃ (R=Y, Sc, Lu) in the temperature range 10K ≤ T ≤ 100K. The comparison between our calculated and available experimental results on the specific heat (C_v) has shown an excellent agreement.

020237   Karthikeyan S;Palaniappan P R;Sabhanayakam S (Physics Dep, St. Joseph's College of Engineering, Chennai-600 119, Email: karthiphy@yahoo.co.in) : FT-IT study of effect of chromium on tissue protein of an edible fish Cirrhinus mrigala. Asian J Chem 2007, 19(2), 1329-33.

Fourier transform infrared spectroscopy (FT-IR) is a powerful technique for molecular conformations of proteins, lip-ids and nuclei acids as well an interaction of the complex materials comprising biological tissues. The present study is aimed to investigate the effect of chromium on tissue protein of an edible fish by FT-IR Technique. The spectra revealed significant differences in band intensities and intensity ratios between treated and control groups. A significant decrease in the protein content was observed in treated samples compared to the control. The amide I band observed at ca. 1657 cm^-1 indicate that the protein is dominated by a-helical structure.

1 table, 22 ref

020236   Jheeta K S;Jain D C;Ravi Kumar;Garg K B (Physics Dep, University of Rajasthan, Jaipur-302 004) : Effect of swift heavy ion irradiation on the optical properties of sapphire. Indian J pure appl Phys 2008, 46(6), 400-2.

Single crystals of sapphire (Al₂O₃; Fe, Ti, Cr) were irradiated with 100 MeV Ti and 100 MeV Ni swift heavy ions (SHI) at fluence 1x10¹², 5x10¹² and 1x10¹³ ions/cm². Photoluminescence (PL) spectra of pristine and irradiated sapphires were recorded at room temperature under 2.8 eV blue excitation. A broad band consisting of two emission bands centered at 2.48 and 2.30 eV corresponding to F² and F₂²⁺ defect centers, respectively, were observed. The concentration of these centers increases monotonically with the Ti ions fluence. While in Ni irradiated sapphires, it increases up to 5x10¹² ions/cm² and then showed a decreasing trend at fluence 1x10¹³ ions/cm². The changes in concentration of these defect centers are explained in term of creation of new defect centers (oxygen vacancies), cluster formation and quenching of these defect centers and are correlated with the nature of ions.

020235   Jain N;Patidar D;Saxena N S;Saraswat Y K (Semiconductor and Polymer Science Lab, Physics Dep, University of Rajasthan, Jaipur 302 004, Email: n_s_saxena@rediffmail.com) : Measurement of thermal properties of polyaniline salt from room temperature 30 to 140°C. Indian J pure appl Phys 2008, 46(6), 385-90.

The thermal transport properties of polyaniline (doped with HCl) have been measured using transient plane source (TPS) technique. Cl- doping is confirmed by FTIR spectroscopy. In the temperature range from room temperature 30 to 140°C both effective thermal conductivity (λ_e) and effective thermal diffusivity (k_e) increase with increase in temperature from 30 to 60°C and become almost constant in the temperature range 60 - 100°C. For further increase in temperature, the values of λ_e and k_e decrease. This behaviour of thermal transport properties in the above mentioned ranges of temperature is due to decrease in moisture content and conversion of single-phase crystalline structure into multiphase crystalline structures, respectively. It has also been found that the values of thermal transport properties are much higher for salt as compared to its base form. This is suggestive of the fact that a change of -NH- group of base form into -[[N⁺H] Cl^-]- group in salt form takes place by doping of chloride ions.

020234   Hasan T;Singh P K;Singhal K;Raj P;Mishra N (Physics Dep, Lucknow Univ, Lucknow-226 007, Email: misraneeraj@gmail.com ) : Normal coordinate analysis and quantum chemical study of tris(p-fluorophenyl) antimony di(N-phenylglycinate) [(p-FC₆H₄)₃Sb(O₂CCH₂NHC₆H₅)< v>2]. Pramana J Phys 2007, 69(4), 675-80.

A complete normal coordinate analysis was performed by two different methods: a classical Wilson's G-F matrix method and the semi-empirical molecular orbital PM3 method, for a five coordinate tris(p-fluorophenyl)antimony di(n-phenylglycinate), [(_p-FC₆H_{4)3 Sb(O2CCH2NHC6H5)2] known to be an in vitro antitumour molecule.}

2 illus, 1 table, 30 ref

020233   Gupta P N (Physics Dep, Faculty of Science, Banaras Hindu University, Varanasi-221 005, Email: guptapn07@yahoo.co.in) : Thermal properties and electrochromic behaviour of PVA complexed electrolytes using PEG as plasticizer. Indian J pure appl Phys 2008, 46(9), 657-9.

Thin films of PVA complexed with H₃PO₄ in different molar ratios using polyethylene glycol (PEG) as plasticizer are prepared by solution cast technique. Thermal study of the system of PVA-H₃PO₄-PEG indicates that glass temperature decreases as acid concentration increases in the presence of the plasticizer and hence, electrical conductivity of the complexed polymer increases. Thin films of higher conductivity are used in the fabrication of electrochromic devices. Optical absorption has been measured in transmission mode and time response of instantaneous change in optical density during colouring and bleaching sequence has been investigated by applying -5.00 to + 5.00V to the WO₃ side with respect to ITO electrode for fixed duration. The modified device using PVA-H₃PO₄-PEG system shows maximum change in optical density (0.13 for the sample PVA-H₃PO₄) and gives higher value of contrast ratio due to high electrical conductivity. It is found that the plasticizer is effective to get shorter response time for the system of PVA-H₃PO₄-PEG in comparison to the PVA-H₃PO₄ system for which observed colouration and bleaching times are 105 and 85 s, respectively.

020232   Gupta H;Mahajan A;Bedi R K (Materials Science Lab, Physics Dep, Guru Nanak Dev University, Amritsar-143 005, Email: srkbedi@rediffmail.com) : Copper phthalocyanine films for photovoltaic applications. Indian J pure appl Phys 2008, 46(6), 435-8.

Hot wall technique has been used to grow a series of copper phthalocyanine (CuPc) films. These samples have been studied for their structural, optical and electrical properties. The X-ray diffraction and SEM pattern of these films show crystalline behaviour of films. The electrical conductivity and optical band gap of the films increase with increase in substrate temperature, whereas activation energy decreases. The activation energy of the films are found to lie in the range 0.45-0.55 eV. Analysis of optical absorption measurements on the films indicates that the interband transitions energies lie in the range 2.3-2.55 eV. Keeping in view, the electrical and optical properties of CuPc films single layer (fluorine doped tin oxide/CuPc/aluminium) and double layer (fluorine doped tin oxide/crystal violet/CuPc/aluminium) junctions have been fabricated under different experimental conditions. The J-V relationship for the single and double layer devices are found to be in good agreement with standard diode equation.

020231   Gunasekaran S;Sailatha E (Spectro Physics Research Lab, Pachaiyappa's College, Chennai-600 030) : Vibrational analysis of pyrazinamide. Indian J pure appl Phys 2008, 46(5), 315-20.

Pyrazinamide (PZA) is an anti-tubercular drug, with molecular formula C₅H₅N₃O. The FTIR and FT Raman spectra of PZA have been recorded in the region 4000-400cm^-1 and 3500-50cm^-1, respectively for molecular study. A detailed vibrational analysis has been made on the fundamental modes of vibration. A normal coordinate analysis has been carried out for PZA following the Wilson's FG matrix method. A set of potential constants has been evaluated using the method of kinetic constants on the basis of C₁ 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 contributes maximum to the potential energy associated with the normal coordinates of the molecule, potential energy distribution (PED) has been evaluated.

020230   Gunasekaran S;Raunbalaji R;Seshadri S;Muthu S (Spectrophysics Research Lab, Physics Dep, Pachaiyappa's College, Chennai-600 030, Email: arunbalaji_81@yahoo.com) : Vibrational spectra and normal coordinate analysis on structure of nitrazepam. Indian J pure appl Phys 2008, 46(3), 162-8.

Normal coordinate analysis on nitrazepam has been carried out with a set of symmetry co-ordinates following Wilson's F-G matrix method. The potential constants evaluated for the molecule are found to be in good agreement with literature values thereby conforming the vibrational assignments. To check whether the chosen set of vibrational frequencies contributes maximum to the potential energy associated with the normal co-ordinates of the molecule, the potential energy distribution has been evaluated.

020229   Gunasekaran S;Kumaresan S;Seshadri S;Muthu S (Spectrophysics Research Lab, Physics Dep, Pachaiyappa's College, Chennai-600 030, Email: yeskay72@yahoo.com) : Vibrational spectra and normal coordinate analysis of structure of procarbazine. Indian J pure appl Phys 2008, 46(3), 155-61.

Procarbazine (C₁₂H₁₉N₃O) is chemically known as N-(1-methylethyl)-4-[N'-(methylhydrazino) methyl] benzamide. It is used as an anti-neoplastic agent. Fourier Transform infrared (FTIR) and Fourier Transform Raman (FTR) spectra of procarbazine have been used for molecular investigation. A detailed vibrational analysis has been made on the fundamental modes of vibration. A normal coordinate analysis (NCA) has been carried out on procarbazine using the Wilson's F-G matrix method. A set of potential constants has been evaluated using the method of kinetic constants on the basis of Cs point group symmetry. The methyl groups are considered as point masses for simplicity. To check whether the chosen set of vibrational frequencies contributes maximum to the potential energy associated with the normal coordinates of the molecule, potential energy distribution (PED) has been evaluated.

020228   Goyal G;Quamara J K (Physics Dep, National Institute of Technology, Kurukshetra-136 119) : Dielectric spectroscopy of 100 MeV Ag ion irradiated polyetherimide. Indian J pure appl Phys 2008, 46(9), 660-6.

The dielectric constant (ε') and loss factor (ε'') have been measured in pristine and 100 MeV Ag ion irradiated (fluences: 5.6x10¹⁰, 1.8x10¹¹ and 1.8x10¹² ions/cm²) polyetherimide (PEI) in the temperature region 30-250°C at different frequencies ranging from 200 Hz to 5 MHz. There is an overall increase in ε' in irradiated samples. This shows the dominance of interfacial polarization arising from the large number of radiation induced defect sites and free radicals. However, the increase in ε' is not directly proportional to the fluence of irradiance. There is a sudden decline in ε' at intermediate fluence (1.8x10¹¹ions/cm²) which is due to the occurrence of new secondary radiation induced crystalline (SRIC) phase. In the low temperature region 30-100°C, the ε' follows the Kirkwood model. Above 100°C, the ε' is almost temperature independent. The radiation induced free radical cross-linking and formation of free radicals have been held responsible for this behaviour. Various relaxation processes revealed their presence in the form of loss peaks in ε''-T curves appearing around 40-50°C, 120-130°C and 180-220°C associated to the dipolar nature of ether linkages, carbonyl groups and space charge relaxation processes, respectively.

020227   Gogoi R;Devi N;Das G C (Mathematics Dep, Cotton College, Guwahati-781001, Email: runmoni_gogoi@rediffmail.com) : Small amplitude solitary waves propagating in a plasma with negative ions. Indian J pure appl Phys 2008, 46(9), 621-8.

One-dimensional motion of positive ions, negative ions and electrons leading to the propagation of K-dV soliton has been considered. Different aspects of soliton amplitude and width have been studied in relation to density ratio (r), mass ratio (Q') of the plasma medium. The role played by the temperature of the negative ions is critically considered to find possible regions of soliton radiation. It is also observed that there are two mutually opposite directions of wave propagation due to the presence of negative ions.