016021   Arora V;Naik P A;Rao B S;Gupta P D (Laser Plasma Div, Raja Ramanna Centre for Advanced Technology, Indore-452 013, Email: arora@rrcat.gov.in) : Comparative study of the ionic keV X-ray line emission from plasma produced by the femtosecond, picosecond and nanosecond duration laser pulses. Pramana J Phys 2012, 78(2), 277-88.

Reports here an experimental study of the ionic keV X-ray line emission from magnesium plasma produced by laser pulses of three widely different pulse durations (FWHM) of 45 ps, 25 ps and 3 ns, at a constant laser fluence of ~1.5 x 10⁴ J cm^-2. It is observed that the X-ray yield of the resonance lines from the higher ionization states such as H- and He-like ions decreases on decreasing the laser pulse duration, even though the peak laser intensities of 3.5 x 10¹⁷ W cm^-2 for the 45 ps pulses and 6.2 x 10¹⁴ W cm^-2 for the 25 ps pulses are much higher than 5 x 10¹² W cm^-2 for the 3 ns laser pulse. The results were explained in terms of the ionization equilibrium time for different ionization states in the heated plasma. The study can be useful to make optimum choice of the laser pulse duration to produce short pulse intense X-ray line emission from the plasma and to get the knowledge of the degree of ionization in the plasma.

5 illus, 39 ref

016020   Ahn C K (Faculty of the Automotive Engineering Dep, Seoul National Science & Technology Univ, 172 Gongneung 2-dong, Nowon-gu, Seoul 139-743, Korea, Email: hironaka@snut.ac.kr) : Robust chaos synchronization based on adaptive fuzzy delayed feedback H∞ control. Pramana J Phys 2012, 78(3), 361-74.

In this paper, author proposed a new adaptive H∞ synchronization strategy, called an adaptive fuzzy delayed feedback H∞ synchronization (AFDFHS) strategy, for chaotic systems with uncertain parameters and external disturbances. Based on Lyapunov-Krasovskii theory, Takagi-Sugeno (T-S) fuzzy model and adaptive delayed feedback H∞ control scheme, the AFDFHS controller is presented such that the synchronization error system is asymptotically stable with a guaranteed Hoc performance. It is shown that the design of the AFDFHS controller with adaptive law can be achieved by solving a linear matrix inequality (LMI), which can be easily facilitated by using some standard numerical packages. An illustrative example is given to demonstrate the effectiveness of the proposed AFDFHS approach.

4 illus, 26 ref

014946   Velusamy V;Palaniappan L (Physics Dep, Paavai College of Engineering, Pachal-637 018) : Ultrasonic analysis of stability and structural properties of biocompatible magnetic fluids. J pure appl Ultrasonics 2011, 33(2), 29-32.

Ultrasound has become a powerful tool in predicting the behaviour of liquid molecules in various environments. Magnetic fluid is a colloidal suspension of magnetic particles in a carrier liquid, stabilized by a surfactant. For biomedical purposes, magnetic particles must be coated with biocompatible substances that ensure their stability, biodegradability and non-toxicity in a physiological medium. The stability and structural properties of some magnetic fluids have been studied by using ultrasonic method. Observed effects are analyzed in the light of the existing studies of magnetic fluids.

3 illus, 1 table, 20 ref

014945   Kumawat D A;Patil J (Research Centre, Botany Dep, Dhanaji Nana Mahavidyalaya, Faizpur-425 503) : Flagellate Pediastrum species from Jalgaon district, Maharashtra. Bioinfolet 2012, 9(4B), 690-1.

While studying the Chlorococcalean algae from polluted and unpolluted habitats of Jalgaon district, Maharashtra, the authors collected 16 taxa of Pediastrum Meyen, out of which, two motile colonial taxa viz. Pediastrum duplex Meyen var. reticulatum Lagerheim and Pediastrum simplex Meyen var. duodenarium (Bailey) Rabenh. were collected from Tapi river near Bhusawal city and Girna river near Jalgaon city. The marginal cell tips of these species were with two thin flagella, which were not reported earlier. The detail description, ecological notes and illustrations of these species have been presented in present paper.

1 illus, 10 ref

013093   Znidaric M (Instituto de Ciencias Fisicas, Nacional Autonoma de Mexico Univ, C.P.62132, Cuernavaca, Morelos, Mexico, Email: marko.znidaric@fmf.uni-Ij.si) : Quantum transport in one-dimensional systems via a master equation approach: numerics and an exact solution. Pramana J Phys 2011, 77(5), 781-91.

Discusses recent findings about properties of quantum nonequilibrium steady states. In particular focus on transport properties. It is shown that the time-dependent density matrix renormalization method can be used successfully to find a stationary solution of Lindblad master equation. Furthermore, for a specific model an exact solution is presented.

4 illus, 32 ref

013092   Yawale P R;Shaligram A D (Electronic Science Dep, Pune Univ, Pune-411 007, Email: yawalepravin@yahoo.co.in) : Experimental and simulation studies on useful life of low power LED illumination sources. J Optics 2011, 40(4), 143-9.

This paper reports experimental and simulation studies on degradation of optical power of low power LEDs due to current stress and temperature variation. The goal of this study was to study the effect of aging and ambient temperature on optical output power of light emitting diodes and to determine the effective life span of LED under stress condition. The LED samples were stressed at four levels of operating current (recommended current 20 mA) 20 mA, 30 mA, 40 mA, and 45 mA with stress time up to 1000 h. We find that degradation rate increases with increasing operating current. When LEDs are overstressed by driving at higher current the optical power degraded with stress time. A Mathematical model is developed to predict the behavior of LED at different operating current. Simulations are carried out with this model using MATLAB. Using degradation pattern at higher operating current the life span of these LEDs was predicted at normal operating current. To verify the simulation results we have used LED life data from different research papers. The authors believe that the model is useful for predicting working life of AlGaInP/AlGaAs/GaAs/GaInN/InGaAsP/InP LED.

5 illus, 2 tables, 13 ref

013091   Wu Y F (Electronic Engineering Dep, Ming Chi Technology Univ, New Taipei City-24301, Taiwan, Email: yfwu@mail.mcut.edu.tw) : Effect of growth interruption on photoluminescence of self-assembled InAs/GaAs quantum dot heterostructures. Indian J pure appl Phys 2012, 50(12), 922-7.

The effects of growth interruption (GI) on self-assembled InAs/GaAs quantum dot (QD) heterostructures have been presented. Samples with different GI times were grown on GaAs substrate by metal-organic chemical vapour epitaxy. Photoreflectance and temperature dependent photoluminescence (PL) spectra from the samples were measured. It is found that increasing GI time during InAs QDs formation induces a larger dot size and a higher QD size uniformity. The carrier dynamics in QD system has been investigated in detail by analyzing the PL spectra. With increasing temperature, thermal redistribution effect among dots is evident for the sample with shorter GI time, leading to a quick red-shift of the PL peak energy and a reduction of the PL line width in mid-temperature range. On the other hand, for sample with longer time, such effect is weak and overcome by the electron-phonon scattering effect, which is consistent with the observed monotonically increasing linewidth of PL spectra with temperature.

7 illus, 1 table, 20 ref

013090   Vudayagiri A (School of Physics, Hyderabad Univ, Hyderabad-500 046, Email: avsp@uohyd.ernet.in) : Quantum logic gates using coherent population trapping states. Pramana J Phys 2011, 77(6), 1127-33.

Scheme is proposed for achieving a controlled phase gate using interaction between atomic spin dipoles. Further, the spin states are prepared in coherent population trap states (CPTs), which are robust against perturbations, laser fluctuations etc. and also show that one-qubit and two-qubit operations can easily be obtained in this scheme. The scheme is also robust against decoherences due to spontaneous emissions as the CPT states used are dressed states formed out of Zeeman sublevels of ground states of the bare atom. However, certain practical issues are of concern in actually obtaining the scheme, which are also discussed at the end of this paper.

3 illus, 12 ref

013089   Verma V K (Physics Dep, Gaya College Gaya, Bihar) : Evaluation of condensation temperature T_c and condensate fraction (N)_o/N as a function of (T)/(T)_c for bose-einstein condensation of trapped atomic gas using non extensive statistical mechanics. J pure appl ind Phys 2013, 3(2), 110-14.

Using theoretical formalism developed by Wang et al. authors have theoretically evaluated the transition temperature T_c of the Bose-Einstein condensation. Our evaluated results of T_c for three Bose condensates are lower than the observed T_c. Also evaluated condensate fracton f -(N_o/N as a function of (T/T_c for three values of non extensive parameter q. (N_o/N)-Jdecrease with (T/T_c for all the three values of q as q=l.l,1.0and 0.8. Our theoretically evaluated results are in good agreements with that of the other theoretical workers.

2 tables, 15 ref

013088   Varinderjit Kaur;Suneel Kumar (School of Physics and Material Science, Thapar Univ, Patiala-147 004, Email: suneel.kumar@thapar.edu) : On the elliptic flow for nearly symmetric collisions and nuclear equation of state. Pramana J Phys 2011, 77(6), 1095-1104.

Presents the results of elliptic flow for the collision of nearly symmetric nuclei (₁₀Ne²⁰+ ₁₃Al²⁷, ₁₈Ar⁴⁰+ ₂₁Sc⁴⁵, ₃₀Zn⁶⁴+ ₂₈Ni⁵⁸, ₃₆Kr⁸⁶+ ₄₁Nb⁹³) using the quantum molecular dynamics (QMD) model. General features of elliptic flow are investigated with the help of theoretical simulations. The simulations are performed at beam energies between 45 and 105 MeV/nucleon. A significant change can be seen from in-plane to out-of-plane elliptic flow of different fragments with incident energy. A comparison with experimental data is also made. Further, we show that elliptic flow for different fragments follows power-law dependence as given by the function C(A_totl)^π.

4 illus, 32 ref

013087   Uniyal M;Bhatt S C;Gairola R P (Dielectric and Ultrasonic Laboratory, Physics Dep, H N B Garhwal Univ, Srinagar, Garhwal-246 174, Email: mani_uniyal@hotmail.com) : Polarizability factor for Na_1-xK_xTaO₃ mixed ceramics. Indian J pure appl Phys 2012, 50(12), 915-17.

Considering a quadratic anharmonic model Hamiltonian and using double time temperature dependent Green's function method and Dyson's equation treatment, expression for polarizability in the frequency response for mixed perovskite type ferroelectrics has been obtained. Using the experimentally observed temperature dependent dielectic constant, loss tangent, soft mode frequency, width for Na_1-xK_xTaO₃ (x = 0, 0.2, 0.4, 0.5 and 0.6) the polarizability has been calculated for these samples at 10 kHz

1 illus, 1 table, 15 ref

013086   Ullmo D;Burdin S;Liu D E;Baranger H U (LPTMS, Paris Sud Univ, CNRS, 91405 Orsay Cedex, France) : Kondo effect and mesoscopic fluctuations. Pramana J Phys 2011, 77(5), 769-79.

Two important themes in nanoscale physics in the last two decades are correlations between electrons and mesoscopic fluctuations. Here author review their recent work on the intersection of these two themes. The setting is the Kondo effect, a paradigmatic example of correlated electron physics, in a nanoscale system with mesoscopic fluctuations; in particular, we consider a small quantum dot coupled to a finite reservoir (which itself may be a large quantum dot), Discuss three aspects of this problem. First, in the high-temperature regime, we argue that a Kondo temperature TK which takes into account the mesoscopic fluctuations is a relevant concept: for instance, physical properties are universal functions of T/T_K. Secondly, when the temperature is much less than the mean level spacing due to confinement, also characterize a natural cross-over from weak to strong coupling. This strong coupling regime is itself characterized by well-defined single-particle levels, as one can see from a Nozieres Fermi-liquid theory argument. Finally, using a mean-field technique, we connect the mesoscopic fluctuations of the quasiparticles in the weak coupling regime to those at strong coupling.

1 illus, 28 ref

013085   Thakkar K;Patel B;Majethiya A;Vinodkumar P C (Physics Dep, Sardar Patel Univ, Vallabh Vidyanagar-388 120, Email: kaushal21185@yahoo.co.in) : Properties of light flavour baryons in hypercentral quark model. Pramana J Phys 2011, 77(6), 1053-67.

Light flavour baryons are studied within the quark model using the hypercentral description of the three-body system. The confinement potential is assumed as hypercentral Coulomb plus power potential (hCPP_v) with power index v. The masses and magnetic moments of light flavour baryons are computed for different power indices, v, starting from 0.5 to 1.5. The predicted masses and magnetic moments are found to attain a saturated value with respect to variation in v beyond the power index v <62> 1.0. Further, we computed transition magnetic moments and radiative decay width of light flavour baryons. The results are in good agreement with the known experimental as well as other theoretical models.

4 illus, 7 tables, 65 ref

013084   Tajendra Kaur;Sinha A S;Singh H S;Kumar S; Mishra L K (Physics Dep, Magadh Univ, Bodh-Gaya) : Evaluation of cyclotron effective mass and electron g-factor in semiconductor quantum well. J pure appl ind Phys 2013, 3(2), 94-101.

Using the theoretical formalism of M. De Dios-Leyva et al. (2006), we have evaluated the cyclotron effective mass, 2D cyclotron effective mass and gn-factor for GaAs-Gao_0.65. Al_0.35AS quantum well both as a function of magnetic field B (T) and also as a function of well width (A). Theoretical evaluated results are in good agreement with the experimental data.

6 tables, 29 ref

013083   Sudheesh P;Sharafudeen K N;Vijayakumar S; Chandrasekharan K (Laser and Nonlinear Optics Laboratory, Physics Dep, National Institute of Technology Calicut, Calicut, Kerala, Email: csk@nitc.ac.in) : Preparation and study of nonlinear optical response of Ag and Au nano particles doped PVA/PVP thin films. J Optics 2011, 40(4), 193-7.

Nanosize Ag and AU were prepared by laser ablation method and the nonlinear optical properties of Ag and Au nanoparticles doped poly-vinylalcohol (PVA) /polyvinylpyrrolidone (PVP) blend films were investigated using Z-scan technique with 7 ns Nd: YAG laser pulses at 532 nm. From open aperture Z-scan measurements it is found that both the Ag/PVA-PVP and Au/PVA-PVP films exhibited reverse saturable absorption. Nonlinear absorption coefficient, nonlinear refractive indices and third-order susceptibility were determined.

7 illus, 1 table, 16 ref

013082   Soni S K;Swami Nandan (Physics Dep, S.G.T.B. Khalsa College, Delhi Univ, Delhi-110 007) : Canonical form of nambu-poisson bracket: a pedestrian approach. Pramana J Phys 2011, 77(6), 1105-17.

In the seventies, Nambu (Phys. Rev. D7, 2405 (1973)) proposed a new approach to classical dynamics based on an N-dimensional Nambu-Poisson (NP) manifold replacing the primitive even-dimensional Poisson manifold and on N-1 Hamiltonians in place of a single Hamiltonian. This approach has had many promoters including Bayen and Flato (Phys. Rev. D11, 3049 (1975)), Mukunda and Sudarshan (Phys. Rev. D13, 2846 (1976)), and Takhtajan (Comm. Math. Phys. 160, 295 (1994)) among others. While Nambu had originally considered N = 3, the illustration of his ideas for N = 4 and 6 was given by Chatterjee (Lett. Math. Phys. 36, 117 (1996)) who observed that the classical description of dynamical systems having dynamical symmetries is described elegantly by Nambu's formalism of mechanics. However, his considerations do not quite yield the beautiful canonical form conjectured by Nambu himself for the N-ary NP bracket. By making a judicious choice for the 'extra constant of motion' of namely, α and β, which are the orientation angles in Kepler problem and isotropic harmonic oscillator (HO) respectively, we show that the dynamical systems with dynamical symmetries can be recast in the beautiful form suggested by Nambu. We believe that the techniques used and the theorems suggested by us in this work are of general interest because of their involvement in the transition from Hamiltonian mechanics to Nambu mechanics.

1 illus, 9 ref

013081   Sivaramaiah G;Rao J L (Physics Dep, Government College for Men, Kadapa-516 004, Email: gsivaram7@yahoo.co.in) : Thermal and magnetic properties of VO<. Proc Indian Natn Sci Acad 2012, 78(1), 51-7.

Using the electron paramagnetic resonance data of VO²⁺ and Cr₃₊ centers in alkali lead borotellurite glasses, the thermodynamic properties such as Gibbs free energy ΔG, entropy AS and enthalpy AH have been evaluated. The effect of temperature, concentration and alkali ions on Gibbs free energy is studied for VO₂₊ and Cr₃₊ centers in alkali lead borotellurite glasses. It is observed that the Gibbs free energy has increased with the increase of concentration and temperature. The Pauli magnetic susceptibility is calculated at different temperatures (123-433 K) for VO₂₊ center in lithium lead borotellurite glass. The Pauli magnetic susceptibility is also calculated for Cr₃₊ center in potassium lead borotellurite glass at different temperatures (123-313 K). The pre-exponential coefficient (PEC) is calculated from the logarithmic of number of spins and the reciprocal of absolute temperature graph of VO₂₊ and Cr₃₊ centers in alkali lead borotellurite glasses. The pre-exponential coefficient indicates the collision frequency between the transition metal ion and the glass lattice. The relaxation time T_m or T₂, is determined from the number of spins and the temperature effect on relaxation time has been studied for the two ions. The Gibbs free energy, pre-exponential coefficient, Pauli magnetic susceptibility, relaxation time are compared between VO₂₊ and Cr₃₊ centers in alkali lead borotellurite glasses. These values are also compared between alkali ions in alkali lead borotellutite glasses.

7 illus, 1 table, 11 ref

013080   Sirohi K;Singh P;Sachin Kumar;Pradeep Kumar; Singh N;Singh J (Basic Education Dep, , Moradabad, Uttar Pradesh) : Analysis of DW and RDW methods in the excitation of Sr atom by electron impact. J pure appl ind Phys 2013, 3(1), 57-61.

Electron impact excitation of atoms has been most extensively studied subject in the field of atomic collision. Present paper carries out non-relativistic distorted wave (DW) and relativistic distorted wave (RDW) approximation method to study the electron impact excitation of n¹D state of Strontium atom from ground state n¹S state. Differential Cross-Section (DCS) results are presented at 15,45, 75 and 105eV incident electron energies.

2 illus, 13 ref

013079   Singh R K (Bharat Sanchar Nigam Limited, BRS Nagar, Ludhiana-141 001, Email: rajivinbhu@gmail.com) : Assessment of electromagnetic radiation from base station antennas. Indian J Radio Space Phys 2012, 41(5), 557-65.

There is a strong perception relating to existence of a high level of non-ionizing electromagnetic radiation in the vicinity of base station antennas. In the present paper, electromagnetic radiation from base station antennas installed for various wireless communication purposes has been investigated based on equivalent isotropically radiated power calculations. For this purpose, a typical wireless communication site has been selected where GSM, CDMA, 3G/UMTS, and WiMAX antennas are installed. The overall ratio of equivalent isotropically radiated power (EIRP) and threshold EIRP combining all services at this particular site has been calculated at ground level and nearby buildings. It has been found that the ratio of EIRP and threshold EIRP is less than unity and thus, the particular site is normally compliant and does not impose any adverse health effects. For general public, the exclusion zone (compliance distance) from GSM, CDMA, 3G/UMTS, and WiMAX antennas have been found at 7.30, 6.076, 7.436, and 6.861 m, respectively.

6 illus, 7 tables, 18 ref

013078   Singh H S;Rohitash Kumar;Bijlani N (Physics Dep, J.N.V. Univ, Jodhpur) : Mossbauer spectroscopic study of the Mahadevpur meteorite Arunachal Pradesh and Assam. J pure appl ind Phys 2013, 3(2), 138-41.

Mossbauer studies of the Mahadevpur meteorite fell, on February 21, 2007 in Arunachal Pradesh and Tinsukia District of Assam, show that the main iron minerals in it are Fe-Ni (Kamacite/taenite), troilite, olivine and pyroxene. These provide characteristic signatures of ordinary chondrites. Mossbauer absorption areas corresponding to different phases favour its classification as H ordinary chondrites.

2 illus, 1 table, 6 ref

013077   Singh D (Physics Dep, D.B.S. (P.G.) College, Kanpur) : Spectrum of strange baryon resonances in hypercentral constituent quark model. J pure appl ind Phys 2013, 3(2), 68-71.

Mass spectra of strange baryons resonances calculated within the framework of a hypercentral constituent quark model. The confinement potential is assumed as a combination of coulomb like term, a linear confining term plus a harmonic oscillator potential. Also study the symmetries of baryon spectrum using a very simple approach based on Gursey - Redicati mass formula. The results of mass spectra of strange baryons resonances is found to be in excellent agreement with the experimental values reported by particle data group over other theoretical model predictions.

2 tables, 13 ref

013076   Singh A K (Physics Dep, A.M. College, Gaya, Bihar) : Evaluation of temperature dependent hall coefficient of high T_c - superconductor. J pure appl ind Phys 2013, 3(2), 186-92.

Using the theoretical formalism of B. Bucher et al. (PRL, 70, 2012) (1993), we have evaluated the temperature dependent Hall Coefficient RH For high Tp Superconductor Y Ba₂ Cu₃O₇-δ (T_C, = 92K) for different values of oxygen deficiency 8. Our theoretical results show that RH increases as a function of temperature and attains maximum value and then decreases. The same behaviour is also observed for others values of 5 as 8 = 0.05, 0.19, 0.23 and 0.39. The theoretically evaluated results are in good agreement with those of the other theoretical workers.

2 tables, 30 ref

013075   Shrawan Kumar;Mishra L K (Physics Dep, G. L. A. College, Daltanganj, Nilamber-Pitamber Univ, Medininagar, Palamu, Jharkhand) : Theoretical study of van hove non-fermi superconductors and analysis of critical temperature degradation. J pure appl ind Phys 2013, 3(2), 156-61.

Non-Fermi behavior of Copper Oxide Superconductors has been analyzed using an energy dependent density of states of the Van Hove (logarithmic) form. The critical temperature degradation due to non-magnetic impurities has been analyzed. The values of critical temperature decrease with non-Fermi parameter α. The width D of the Van Hove singularity affects critical temperature. The larger value of D gives large value of It has been shown that the decrease of the critical temperature is not of the Abrikosov-Gorkov type.

2 tables, 25 ref

013074   Shojai F;Shojai A (Physics Dep, Tehran Univ, Tehran, Iran, Email: fshojai@ut.ac.ir) : Non-minimal quintessence: dynamics and coincidence problem. Pramana J Phys 2011, 77(6), 1179-89.

Brans-Dicke scalar-tensor theory provides a conformal coupling of the scalar field with gravity in Einstein's frame. This model is equivalent to an interacting quintessence in which dark matter is coupled to dark energy. This provides a natural mechanism to alleviate the coincidence problem. Investigates the dynamics of this model and show that it leads to comparable dark energy and dark matter densities today.

5 illus, 27 ref

013073   Sharma M;Gairola R P (NO, Govt. College Dhaliara, Himachal Pradesh) : Current study of rare earth magnetism and evaluation of magnetic structure of holonium. J pure appl ind Phys 2013, 3(2), 178-85.

Magnetic properties of the rare earth metals differ, in many aspects, from those of other metals in the periodic table of elements. A most amazing effect arises, when several electrons are put together and are treated as one many-particle system. By virtue of their Fermionic character, an additional interaction occurs named as Exchange. This interaction is a consequence of the fact, that two identical particles cannot be distinguished in quantum Physics. Note that there is a crucial difference between rare earth metals and transition metals although both species possess open inner shells, 4f shells in the case of rare earths, and 3d, 4d or 5d shells respectively in the case of transition metals. The latter are rather delocalized and their wave functions reach far enough, to overlap with the respective neighboring wave functions whereas 4f electrons of rare earth ion cores are fully localized. Exchange interaction between the localized spins of 4f shells is an indirect one, being mediated by the 6s and, if available, the 5d conduction electrons. To point out the prominent part of rare earths among the magnetic metals, a new approach with electronic structure of the rare earth 3+ ion cores and indirect exchange between their localized magnetic moments in the metal is described. Finally, the magnetic structure of holmium is discussed. Where it has been found that in rare earth metals, conduction electrons play the crucial part in magnetic ordering & the structure of the localized magnetic moments matches experimentally as well as theoretically.

4 illus, 1 table, 19 ref

013072   Sharma A;Shrimali M D (NO, The LNM Institute of Information technology, Jaipur-302 031, Email: m.shrimali@gmail.com) : Synchronization of indirectly coupled lorenz oscillators: an experimental study. Pramana J Phys 2011, 77(5), 881-9.

Dynamics of indirectly coupled Lorenz circuits is investigated experimentally. The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev. E 81, 046216 (2010) is verified by physical experiments with electronic circuits. Two chaotic systems coupled through a common dynamic environment shows the verity of synchronization behaviours such as anti-phase synchronization, in-phase synchronization, identical synchronization, anti-synchronization, etc.

5 illus, 30 ref

013071   Shanker J;Anand K;Singh P K (Physics Dep, Institute of Basic Sciences, Dr B R Ambedkar Univ, Khandari Campus, Agra-282 002, Email: pramod0002000@yahoo.com) : Free-volume theory of the Gruneisen parameter at extreme compression. Indian J pure appl Phys 2012, 50(12), 918-21.

Analysis of the Gruneisen parameter and its volume derivatives has been presented using the generalized free-volume theory for materials at extreme compression. It has been re-established using a direct and simple method that the Slater's formula for the Gruneisen parameter has the status of an identity at infinite pressure as found earlier by Stacey and Davis (Phys Earth Planet Inter, 142 (2004) 137). The expressions based on the free-volume theory extrapolated to infinite pressure are found to be in agreement with the corresponding expressions for higher-order Gruneisen parameters obtained recently by Shanker et al. (Physica B, 404 (2009) 4083).

18 ref

013070   Shah K;Upadhyay R V (P.D. Patel Institute of Applied Sciences and K.C. Patel R & D Center, Charotar Science & Technology Univ, Education Campus, Changa-388 421) : Experimental investigation od ultrasonic velocity anisotropy in magnetic fluids: influence of grain-grain interaction. Pramana J Phys 2011, 77(2), 345-55.

Magnetic field-induced dispersion of ultrasonic velocity in a Mn_0.7Zn_0.3Fe₂O₄ fluid (applied magnetic field is perpendicular to the ultrasonic propagation vector) is determined by employing continuous wave method. The magnitude of dispersion initially decreases with increasing field, then increases and reaches a plateau at higher fields. Results indicate that the velocity anisotropy is dominated by grain-grain interactions rather than grain-field interaction. At the critical temperature, the grain-grain interaction becomes weak as the transverse component of the particle/cluster moment is larger than the longitudinal one and the system reaches saturation even at low field. These observed variations in the field-induced anisotropy are analysed by incorporating the moment distribution of particles in Tarapov's theory (J. Magn. Magn. Mater. 39, 51 (1983)).

9 illus, 33 ref

013069   Sethia G C;Sen A;Atay F M (NO, Institute for Plasma Research, Bhat, Gandhinagar-382 428, Email: gautam@ipr.res.in) : Phase-locked solutions and their stability in the presence of propagation delays. Pramana J Phys 2011, 77(5), 905-15.

Investigates phase-locked solutions of a continuum field of nonlocally coupled identical phase oscillators with distance-dependent propagation delays. Equilibrium relations for both synchronous and travelling wave solutions in the parameter space characterizing the nonlocality and time delay are delineated. For the synchronous states a comprehensive stability diagram is presented that provides a heuristic synchronization condition as well as an analytic relation for the marginal stability curve. The relation yields simple stability expressions in the limiting cases of local and global coupling of phase oscillators.

4 illus, 15 ref

013068   Saxena G;Prasad A;Ramaswamy R (Physics and Astrophysics Dep, Delhi Univ, Delhi-110 007, Email: gsaxena2006@yahoo.co.in) : Effect of finite response-time in coupled dynamical systems. Pramana J Phys 2011, 77(5), 865-71.

Paper investigates synchronization in unidirectionally coupled dynamical systems wherein the influence of drive on response is cumulative: coupling signals are integrated over a time interval τ. A major consequence of integrative coupling is that the onset of the generalized and phase synchronization occurs at higher coupling compared to the instantaneous (τ = 0) case. The critical coupling strength at which synchronization sets in is found to increase with τ. The systems explored are the chaotic Rossler and limit cycle (the Landau-Stuart model) oscillators. For coupled Rossler oscillators the region of generalized synchrony in the phase space is intercepted by an asynchronous region which corresponds to anomalous generalized synchronization.

2 illus, 23 ref

013067   Sanjay Kumar;Barnwal A K;Poddar P (Physics Dep, Magadh Univ, Bodhgaya) : Electrical resistivity of Beryllium. J pure appl ind Phys 2013, 3(2), 88-92.

In this paper we have analysed the electrical resistivity of two different specimen of Be. Both specimen display a relatively high residual resistance. In both cases the ideal resistivity is very small. The behaviour of electrical resistivity of Be is strongly suggestive of impurity semiconductor properties and concords with the fact that the soft x-rays emission spectrum behaves as though the levels of a single zone almost completely occupied indicating that this metal is very nearly an insulator. From the analysis of reported data we have got two contradictory results, viz, metallic character and semiconducting character. Finally got Be behaves as semiconductor at low temperatures and when temperature increases it behaves normal metallic character at high temperatures.

3 illus, 3 tables, 13 ref

013066   Saiyed B A (NO, Shree P.M. Patel College of Electronics & Communication, Anand) : Electrical behaviour and conduction in cadmium oxalate single crystals. J pure appl ind Phys 2013, 3(1), 23-6.

Characterization of the grown cadmium oxalate single crystals is an essential requirement to describe, confront and explain their various properties. Cadmium oxalate trihydrate (CdC₂O-3H₂O) single crystals suitable for the present investigation were grown using controlled diffusion process in silica gels. The investigation on electrical parameters of cadmium oxalate has been carried out to understand the mechanism of charge transport. The dc conductivity of cadmium oxalate occurs between the normal conductivities of semiconductor and insulator. The obtained value of exponent p (=0.54) characterises Efros hopping conduction mechanism in our sample. The activation energy required to move permanent intrinsic defects in the crystal lattice is equal to 0.75 eV.

1 illus, 11 ref

013065   Sahu M K;Chandra B P (Physics of Sound Dep, Indira Kala Sangit Vishwavidyalaya Khairagarh, C.G.) : Fracto mechanoluminescence in coloured alkali halide crystals. J pure appl ind Phys 2013, 3(2), 128-32.

In coloured alkali halide crystals the recombination of electrons with V2-centres in the crystal may give rise to the delayed luminescence where the delay time will depend on the life time of the electrons in the shallow traps. The time dependence of the ML intensity in coloured alkali halide crystals, which suggest that there should be two peaks in the ML intensity versus time curves of the crystals, where one peak should be in the deformation region and the other should be in post deformation region in the crystals.

3 illus, 5 ref

013064   Sahu M K (Physics of Sound Dep, Indira Kala Sangit Vishwavidyalaya Khairagarh, Khairagarh, Chattisgarh) : Theory of mechanoluminescence produced during cleavage of elemantal and III-V semiconductors. J pure appl ind Phys 2013, 3(2), 134-7.

Present paper reports that the formation of crack-induced localized state is responsible for the Mechano luminescence (ML) produced during the cleavage of elemental and III-V semiconductors. When an elemental and III-V semiconductor is cleaved, initially the ML intensity increases with time and attains a peak value I_mat the time tm corresponding to completion of the cleavage of the semiconductor and then it decreases following power law decay. Both I_m and I_T increases linearly with the area of newly created surfaces of the crystals. From the measurements of the ML intensity, the velocity of crack propagation in material can be determined by using the relation v=H/t_m.

2 illus, 7 ref

013063   Sahu M K (Physics of Sound Dep, Indira Kala Sangit Vishwavidyalaya Khairagarh, C.G.) : Theoretical approach to the mechanoluminescence produced during the deformation of II-VI compounds. J pure appl ind Phys 2013, 3(2), 124-7.

Present paper reports the tunneling mechanoluminescence (ML) produced during deformation of II-VI compounds. The ionization of trapped electrons may occur by the tunneling of electron from the trapping level to the conduction band under the operation of strong electric field close to the charged dislocations. The electrons released from the filled traps may move in this conduction band and they may recombine with the luminescence center, giving rise to the luminescence characteristics of activator centers. Based on this fact, equations are derived for rise and decay of ML intensity and also for the saturation value of the ML intensity. It is found that the ML intensity should depend on the number of filled trap N_c, radius of interaction r_i, strain rate œ and volume of crystal V. It is found that there is a good agreement between theoretical and experimental results.

2 illus, 8 ref

013062   Sahu M K (Indra Kala Sangeet Vishwavidyalaya, Khairagarh, Chhattisgarh) : Theoretical approach to the laser-stimulated luminescence in II-VI semiconductor. J pure appl ind Phys 2013, 3(1), 15-21.

Present paper reports the laser mechanoluminescence (ML) in II-VI semiconductors. When a II-VI semiconductor exposed to laser pulse they will produce a shock-wave in the crystal and consequently the deformation of crystal takes place. Also obtain the rate of generation of electron in the shallow traps and number of electrons in the shallow trap finally. The decay time of ML will be equal to the life time of electrons in the shallow traps. Finally authors obtain the ratio of I_m2 and I_m1. The ratio I_m2/I_m2 depend on the probability of transfer of electrons from the conduction band to shallow traps and on the ratio of pinning time of dislocation and life time of electrons in the shallow traps. By using laser pulse and an optical fiber the ML may be observed owing to the movement of single dislocation in II-VI semi-conductors.

15 ref

013061   Sahu M K (Indra Kala Sangeet Vishwavidyalaya, , Khairagarh, Chhattisgarh) : Elastico mechano luminescence in crystals. J pure appl ind Phys 2013, 3(1), 11-14.

Present paper reports phenomenon of mechanoluminescence (ML), ML measuring devices and the applications of ML. The characteristics of the elastic ML of mechanoluminescent material such as SrAl₂O₄:Eu microparticles mixed in epoxy resin and the thin film of ZnS:Mn nanoparticles are discussed in which elastico ML was induced either by slow compression or by impact stress. The piezoelectrically-stimulated detrapping model is found to be suitable for the EML of SrAl₂O₄: Eu microparticles and ZnS:Mn nanoparticles. The applications of mechanoluminescent materials in stress, fracture, impact and damage sensors, displays; visualizations of the stress distribution in solids are discussed. The perspectives for research on ML are explored. It is shown that the development of a safety monitoring network system using ML sensors to detect danger's sign of structural objects such as pipelines the use of ML sensors in getting prior information of the occurrence of earth quakes and mine-failure are the current challenges in this field.

15 ref

013060   Sahoo S;Sit S K (Electronics & Instrumentation Engineering Dep, Dr Meghnad Saha Institute of Technology, P.O. Debhog, Haldia, Purba Medinipur-721 657, Email: swapansit@yahoo.co.in) : Dielectric behaviour of some amides and formamides dissolved in nonpolar solvents under static electric field. Pramana J Phys 2011, 77(2), 395-404.

Structural and associational aspects of polar amides (j) like formamide, acetamide, N-methyl acetamide (NMA), N,N-dimethyl formamide (DMF), N,N-dimethyl acetamide (DMA) and acetanilide dissolved in the nonpolar solvent (i) benzene or 1,4-dioxan have been estimated from the measured static relative permittivity εOij and high-frequency permittivity ε_∞ij at different weight fractions WjS of polar solute at 35°C under static electric field using Debye model of polar liquid molecule. The static dipole moments μ_ss are compared with μjs reported from conductivity method and theoretical μ_theoS to get exact μ_cal. μ_theoS of the molecules are predicted from the available bond angles and bond moments where difference in electron affinity exists between two adjacent atoms of a polar group due to inductive, mesomeric and electromeric effects in them. Solute-solute molecular association for NMA in benzene and solute-solvent association for other amides are ascertained to arrive at their conformational structures.

2 illus, 2 tables, 12 ref

013059   Rosli N B;Okhunov A A;Kassim H A (Theoretical Physics Laboratory, Physics Dep, Malaya Univ, Malaysia, Email: norrarosly88@yahoo.com) : Low-energy structure of isotopes <. Indian J pure appl Phys 2012, 50(12), 887-91.

The ^152-156Sm isotopes are classified as deformed nuclei. The phenomenological model is presented to describe the complete low-energy structure of ^152-156Sm isotopes by taking into account the Coriolis mixing between states. The parameters fitted to the model are calculated. The energy spectra of positive-parity states which are found to be in good agreement with the experimental data are presented. It is found that the non-adiabaticity of rotational energy bands occurred at high spin due to the Coriolis effect. Few new states are predicted.

4 illus, 5 tables, 13 ref

013058   Rajeev Kumar;Mishra L K (Physics Dep, Swami Sajhanand College, Chas Bokaro, Jharkhand) : Evaluation of super fluid density (P_s/P) as a function of (T/T_c for BCS-BEC crossover regime. J pure appl ind Phys 2013, 3(2), 148-54.

Studied the BCS-BEC cross over regime by evaluating the energy gap parameter and the chemical potential for the crossover as a function of dimensional parameter. The theoretical results indicate that cross-over occurs in the very small regions of the parameter. Also evaluated the ratio of super fluid density to the total density(ρ/ρ) as a function of (T/T_c) for three limits BCS, Pseudo gap and BEC. These results are quite useful in the study of dynamical properties of BCS-BEC crossover region at finite temperature.

3 tables, 20 ref

013057   Prasanna Kumar S;Umesh T K (J.S.S. Academy of Technical Education, Mylasandra, Bangalore-560 060, Email: tku@physics.uni-mysore.ac.in) : Experimental measurement of effective atomic number of composite materials for compton effect in the γ-ray region 280-1115 keV by a new method. Pramana J Phys 2011, 77(2), 335-44.

In this paper, we report a new method to determine the effective atomic number, Z_eff of composite materials for Compton effect in the γ-ray region 280-1115 keV based on the theoretically obtained Klein-Nishina scattering cross-sections in the angular range 50°-100° as well as a method to experimentally measure differential incoherent (Compton) scattering cross-sections in this angular range. The method was employed to evaluate Z_eff for different inorganic compounds containing elements in the range Z = 1-56, at three scattering angles 60°, 80° and 100° at three incident gamma energies 279.1 keV, 661.6 keV and 1115.5 keV and we have verified this method to be an appropriate method. Interestingly, the Z_eff values so obtained for the inorganic compounds were found to be equal to the total number of electrons present in the sample as given by the atomic number of the elements constituting the sample in accordance with the chemical formula of the sample. This was the case at all the three energies.

3 illus, 5 tables, 8 ref

013056   Prasad P D S;Mishra L K (Physics Dep, R.K.D. College Patna, Bihar) : Evaluation of colletive mod of one-dimensional fermi gas in weak and strong coupling limit. J pure appl ind Phys 2013, 3(2), 116-23.

Collective mode of one-dimensional Fermi gas has been evaluated over the whole coupling regime from weak coupling (high density) to strong coupling (low density). The evaluation has been performed using theoretical model of Alam and Schuck taking attractive 8 interaction potential under RPA approximation at zero temperature and observe that in the weak-coupling limit particle-hole RPA approaches to low momenta and the collective mode in the strong coupling limit reproduces the Bogoliubov mode for the weakly interacting bosons. The theoretically evaluated results are in good agreement with other theoretical workers.

2 tables, 37 ref

013055   Pragash R;Unnikrishnan N V;Sudarsanakumar C (School of Pure and Applied Physics, Mahatma Gandhi Univ, Kottayam-686 560, Email: pragashramnivas@yahoo.co.in) : Spectroscopic properties of Pr<. Pramana J Phys 2011, 77(6), 1119-26.

Spectroscopic properties of praseodymium ions-doped erbium oxalate (Er₂(C₂O₄)₃ nH₂O) crystals have been investigated. The crystals were grown by hydro silica gel method under suitable pH conditions and by single diffusion method. The well-grown crystals are bright and transparent. The dark green colour of these crystals changes with the variation of the concentrations of the dopant ions. The absorption spectra have been measured in the region 200-800 nm at room temperature. Judd-Ofelt intensity parameters for f-f transitions of the Pr³⁺ ions have been determined as Ω₂ = 166.7, Ω₄ = 1.103 and Ω₆

5 illus, 3 tables, 14 ref

013054   Porsezian K;Vasantha Jayakantha Raja R (Physics Dep, School of Physical Chemical and Applied Sciences, Pondicherry Univ, Puducherry-605 014, Email: ponzsol@yahoo.com) : Soliton-induced supercontinuum generation in liquid-filled photonic crystal fibre. Pramana J Phys 2011, 77(5), 959-74.

Aim to study the nonlinear optical phenomena with ultra-broadband radiation in photonic crystal fibre (PCF). While PCFs with cores made from different glasses are well studied in previous works, in this paper, it is planned to investigate the dynamics of nonlinear processes of supercontinuum generation (SCG) in liquid-filled PCF (LCPCF) to understand the physical phenomena of femtosecond pulse propagation, particularly, the temporal and spectral changes of the pulse propagating through specific PCFs. Since the CS₂-filled LCPCF has complex nonlinear phenomena, Intend to analyse the role of saturable nonlinear response and slow nonlinear response on SCG in detail. For the physical explanation, soliton fission and modulational instability techniques will be implemented to investigate the impact of slow nonlinear response and saturable nonlinear response respectively, in SCG process.

11 illus, 31 ref

013053   Pensia R K;Shrivastava V;Patidar A K;Kachhawa G S;Sutar D L (Physics Dep, Govt. Girls College, Neemuch, Madhya Pradesh) : Effect of quantum correction on disturbances propagating in the gaseous plasma having fine dust particles. J pure appl ind Phys 2013, 3(1), 49-55.

Problem of Jeans instability of gaseous plasma in the presence of fine dust particles under the influence of quantum correction has been investigated. The equations of the problem ate stated and a general dispersion relation is obtained using normal mode analysis with the help of relevant linearized perturbation equations of the problem and a modified Jeans criterion of instability is obtained. The stability of the system is discussed by Routh-Hurwitz criterion of stability.

23 ref

013052   Pensia R K;Kumar V;Kachhawa G S;Patidar A K; Shrivastava V (Physics Dep, Govt. Girls (P.G.) College, Neemuch, M.P.) : Jeans instability of rotating viscous molecular cloud of quantum plasma under the effect of black-body radiation. J pure appl ind Phys 2013, 3(2), 172-7.

Problem of Jeans instability of rotating viscous molecular cloud of quantum plasmas has been investigated as considering the optically thick medium incorporating effect of porosity, permeability and black body radiation. The equations of the problem are stated and dispersion relation is obtained using normal mode analysis. The criterions of instability are discussed as our interest.

20 ref

013051   Paul Kumar U;Somasundaram U;Krishna Mohan N; Kothiyal M P (Applied Optics Laboratory, Physics Dep, Indian Institute of Technology Madras, Chennai-600 036, Email: nkmohan@iitm.ac.in ) : Comparative study of time average and stroboscopic illumination techniques for vibration fringe analysis. J Optics 2011, 40(4), 184-92.

TV holography is a whole field non-contact optical measuring tool for qualitative and quantitative measurement of resonance mode shapes of engineering structures under harmonic excitation. This paper presents results of our experiments for the vibration fringe analysis using TV holography with the continuous and the stroboscopic illumination which provide the time-average or the time-resolved respectively of the object vibration modes at resonant frequencies. A comparison between the two methods is highlighted in this paper.

9 illus, 17 ref

013050   Paul Kumar U;Krishna Mohan N;Kothiyal M P (Applied Optics Laboratory, Physics Dep, Indian Institute of Technology Madras, Chennai-600 036, Email: nkmohan@iitm.ac.in) : Red-green-blue wavelength interferometry and TV holography for surface metrology. J Optics 2011, 40(4), 176-83.

Surface discontinuities greater than half a wavelength can not be measured unambiguously using single wavelength interferometry. In TV holography, it is difficult to quantify the data under relatively large loading conditions due to the overcrowding of fringes with a single wavelength. Further, single wavelength does not reveal the contour of rough surfaces with TV holography. Multiple wavelengths measurements using red, green, and blue wavelengths can overcome these problems. In this paper a multiple wavelength interferometric system with colour CCD is demonstrated for such measurements. The interference patterns are recorded by a single chip colour CCD camera which makes the data acquisition as simple as in single wavelength case. The interference pattern is decomposed into its R G B components to evaluate the phase at individual wavelengths. An eight step phase shifting algorithm is used to simplify the application of phase shifting technique in the multiple wavelength system. Experimental results on an etched silicon sample for the measurement of large discontinuities and on a MEMS pressure sensor for the measurement of shape and relatively large deflection are presented.

6 illus, 16 ref

013049   Pandikumar G;Gopalakrishnan V;Mohanakrishnan P (Reactor Physics Group, Indira gandhi Centre for Atomic Research, Kalpakkam-603 102, Email: vgk@igcar.gov.in) : Improved analysis on multiple recycling of fuel in prototype fast breeder reactor in a closed fuel cycle. Pramana J Phys 2011, 77(2), 315-33.

An FBR closed fuel cycle involves recycling of the discharge fuel, after reprocessing and refabrication, to utilize the unburnt fuel remains and the freshly bred fissile material. Our previous study in this regard for the PFBR indicated a comfortable feasibility of multiple recycling with self-sufficiency. In the present work, more refined estimations are done using the most recent nuclear data, viz. ENDF/B-VIL.O, and with the most recent specification of the fuel composition. Among others, this paper brings out the importance of taking into account the energy self-shielding effects in the cross-section averages used in the study. While self-shielded averages lead to realistic predictions, unshielded averages significantly overpredict breeding in the blankets and underpredict loss in the cores.

10 illus, 11 tables, 6 ref

013048   Pal H;Santhanam M S (Physical Research Laboratory, Navrangpura, Ahmedabad-380 009, Email: santh@iiserpune.ac.in ) : Classically induced suppression of energy growth in a chaotic quantum system. Pramana J Phys 2011, 77(5), 793-802.

Recent experiments with Bose-Einstein condensates (BEC) in traps and speckle potentials have explored the dynamical regime in which the evolving BEC clouds localize due to the influence of classical dynamics. The growth of their mean energy is effectively arrested. This is in contrast with the well-known localization phenomena that originate due to quantum interferences. It show that classically induced localization can also be obtained in a classically chaotic, non-interacting system. In this work, we study the classical and quantum dynamics of non-interacting particles in a double-barrier structure. This is essentially a non-KAM system and, depending on the parameters, can display chaotic dynamics inside the finite well between the barriers. However, for the same set of parameters, it can display nearly regular dynamics above the barriers. Also exploit this combination of two qualitatively different classical dynamical features to obtain saturation of energy growth. In the semiclassical regime, this classical mechanism strongly influences the quantum behaviour of the system.

4 illus, 6 tables, 13 ref