Indian Journal of Pure and Applied Physics

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VOLUME 47

NUMBER 11

NOVEMBER 2009

CODEN:IJOPAU 47(11) 757-832

 

ISSN:0019-5596

 

CONTENTS
 
   

Nuclear Physics

 

 

Multifractality assessment in high energy nuclear collisions with levy index in self affine scenario

        Dipak Ghosh, Argha Deb, Swarnapratim Bhattacharyya* & Utpal Datta

 

761

Atomic and Molecular Physics

 

 

Mechanism of green luminescence in ZnO

        R Bhaskar, A R Lakshmanan*, M Sundarrajan, T Ravishankar, M T Jose & N Lakshminarayan

 

772

Luminescence efficiency of Eu+3 in Y2O3: The effect of reduction of particle size and incorporation

of trace hetero-cations in the Y2O3 lattice

        A Nayak, K Goswami, A Ghosh & R Debnath*

 

775

Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics and Fluid Dynamics

 

 

Ultrasonic and theoretical studies of some ternary liquid mixtures at various temperatures

        T Sumathi* & J Uma Maheswari

 

782

Condensed Matter: Structural, Mechanical and Thermal Properties

 

 

Structural and electrical properties of polycrystalline AgxGa2-xSe2  thin films

        M R A Bhuiyan*, D K Saha & S M Firoz Hasan

 

787

Electronegativity, fractional ionic character and refractive index of binary compounds

        B P Singh*, V S Baghel & K S Baghel

 

793

Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties

 

 

Electronic and elastic properties of alkali-metal sulphides-Li2S and Na2S

        Premlata Pandit*, Bipul Rakshit & Sankar P Sanyal

 

804

Screening current and dielectric parameters in dual QCD

        Hemwati Nandan*, Nils M Bezares-Roder & H C Chandola

 

808

Interdisciplinary Physics and Related Areas of Science and Technology

 

 

Novel minimum-component universal filter and quadrature oscillator with electronic tuning property

based on CCCDBAs

        Worapong Tangsrirat*

 

815

Experimental and numerical realization of higher order autonomous Van der Pol-Duffing oscillator

        V Balachandran,* & G Kandiban

 

823

 

 Authors for correspondence are indicated by (*)

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 761-771

 

 

Multifractality assessment in high energy nuclear collisions with
levy index in self affine scenario

 

Dipak Ghosh, Argha Deb, Swarnapratim Bhattacharyya* & Utpal Datta

Nuclear and Particle Physics Research Centre, Department of Physics, Jadavpur University, Kolkata 700 032

* Department of Physics, New Alipore College, L Block, New Alipore, Kolkata 700 052

E-mail: swarna_pratim@yahoo.com

Received 4 September 2008; revised 25 August 2009; accepted 22 September 2009

Degree of multiplicity assessment with Levy stable index in the target fragmentation of 28Si-AgBr interactions at
14.5 AGeV, 32S-AgBr interactions at 200AGeV and 16O-AgBr interactions at 60AGeV in emission angle space and azimuthal angle space separately and also in two dimensional anisotropic (cos
q-f) space has been studied. The analysis reveals that the values of Levy index lie within 1 and 2. For all the three interactions and for all the cases the values of Levy indices are different suggesting different degree of multifractality in different interactions.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 772-774

 

 

Mechanism of green luminescence in ZnO

 

R Bhaskar1, A R Lakshmanan*1, M Sundarrajan1, T Ravishankar1, M T Jose2 & N Lakshminarayan3

1Physics Department, Saveetha Engineering College, Thandalam, Chennai 602 105

2Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam  603 102

3Madras Christian College, Tambaram, Chennai 600 059

*E-mail: arunachalamlakshmanan@yahoo.com

Received 13 January 2009; accepted 7 September 2009

ZnO grown under reducing condition is always Zn excess. These Zn atoms are positioned at interstitial sites due to the escape of oxygen from ZnO. The oxygen vacancies created by alkali metal dopants in ZnO play a major role in its green luminescence. This is understood on the basis of charge transfer between Zn interstitials and neighbouring oxygen vacancies caused by the doping of monovalent ions such as Li, Na or K at divalent Zn lattice sites followed by Stokes shifted emission.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 775-781

 

 

Luminescence efficiency of Eu+3 in Y2O3: The effect of reduction of particle size and incorporation of trace hetero-cations in the Y2O3 lattice

 

A Nayak, K Goswami1, A Ghosh & R Debnath*

Central Glass and Ceramic Research Institute, 196, Raja S C Mullick Road, Kolkata 700 032

1Department of Physics, Jadavpur University, Kolkata-700 032

E-mail: debnath@cgcri.res.in

Received 12 December 2008; revised 28 April 2009; accepted 26 August 2009

The effect of incorporation of trace (Al+3, B+3) in the Y2O3 lattice on the luminescence efficiency of Y2O3:Eu+3 red phosphor has been investigated. It is observed that such incorporation causes an enhancement of 5D07F2 red luminescence efficiency as well as the associated excitation efficiency of Eu+3. It is concluded that there occurs a change in the polarity of the host rather than the site symmetry of Eu+3 due to incorporation of the hetero cations. Calculation of the Judd-Ofelt parameters gives similar results. In another study, to observe the effect of reduction of particle size on the luminescence efficiency of the Y2O3:Eu+3, the change in luminescence efficiency of the phosphor with the reduction particle size and the stability of the different efficiencies with the elapse of time have been investigated. The samples with particle size below 100 nm showed a significant loss in luminescence efficiency and a change in their excitation profile with time. IR studies showed that although the freshly prepared samples were almost free from contaminated water, on ageing in air at room temperature, they absorb the latter. A phenomenon of hydration induced coupling of the excitonic state of Y2O3 with one of its Fu modes, has been detected in the case of the aged samples which susequently introduces newer non-radiative channels in the system causing a decrease in the luminescence efficiency of the phosphor. Because of larger surface to volume ratio, the effect is most pronounced in nanocrystalline samples.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 782-786

 

 

Ultrasonic and theoretical studies of some ternary liquid mixtures
at various temperatures

 

T Sumathi* & J Uma Maheswari

Department of Physics, DDE, Annamalai University, Tamilnadu

*E-mail: tsumathi92@yahoo.com

Received 14 October 2008; revised 22 July 2009; accepted 12 August 2009

Various acoustical parameters such as adiabatic compressibility (b), free length (Lf), free volume (Vf), internal pressure (pi), excess adiabatic compressibility (bE), excess free length (LfE), excess free volume (VfE), excess internal pressure (piE), excess viscosity (hE) and excess velocity (UE) have been evaluated from density, viscosity and speeds of sound measurements for solvent systems consisting of methyl acetate and toluene with 1-pentanol, 1-hexanol and 1-heptanol at 303.15, 308.15 and 313.15 K. These excess properties have been used to discuss the presence of significant interactions between the component molecules in the ternary mixtures. The ultrasonic speeds calculated according to Nomoto’s relation, impedance dependence relation and collision factor theory are compared with those obtained experimentally.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 787-792

 

 

Structural and electrical properties of polycrystalline
AgxGa2-xSe2  thin films

 

M R A Bhuiyan*,1, D K Saha & S M Firoz Hasan

*Department of Applied Physics, Electronics and Communication Engineering, Islamic University
Kushtia 7003, Bangladesh

Materials Science Division, Experimental Physics Division, Atomic Energy Centre, GPO Box 164
Dhaka 1000, Bangladesh

1E-mail: mrab_iu@yahoo.com

Received 18 May 2009; revised 26 August 2009; accepted 24 September 2009

Thin films of AgxGa2-xSe2 (AGS) have been prepared onto glass substrates by stacked elemental layer (SEL) deposition technique in vacuum. The atomic composition of the films has been measured by energy dispersive analysis of X-ray (EDAX) method. The structural and electrical properties of the films are ascertained by X-ray diffraction (XRD) and standard dc method using a cryostat, respectively. The structural and electrical parameters have been found for different non-molecularity of the films. The films ascertain the compositional uniformity. The X-ray diffraction (XRD) reveals that the films are polycrystalline in nature. The electrical conductivity of the films (at room temperature) having different
non-molecularity has been found to vary from 1.36
´10-6 to 4.93´10-3 (W-cm)-1. These films support thermally activated process. The activation energies vary between 21.61 and 60.64 meV as non-molecularity varies between -0.798 and 1.710.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 793-803

 

 

Electronegativity, fractional ionic character and refractive
index of binary compounds

 

B P Singh*, V S Baghel# & K S Baghel

Department of Physics, Institute of Basic Sciences, Khandari, Agra 282 002

E-mail: *drbps_ibs@yahoo.co.in; #vipneshbaghel@yahoo.co.in

Received 20 January 2009; accepted 2 July 2009

An analysis is presented for the electronegativity, fractional ionic character and refractive index of binary compounds with monovalent, divalent and trivalent atoms. The values of electronegativity difference by investigating a relationship between fractional ionic character and electronegativities have been determined. More accurate values of ionicity based on the revised energy gap model have been used in the present study to obtain the new results. The values of electronegativity difference are found to be correlated well with the values of refractive index and energy gap in case of I-VII, II-VI and III-V binary compounds.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 804-807

 

 

Electronic and elastic properties of alkali-metal sulphides-Li2S and Na2S

 

Premlata Pandit*, Bipul Rakshit & Sankar P Sanyal

Computational Research Laboratory, Department of Physics, Barkatullah University, Bhopal 462 026

*E-mail: lataprem29@gmail.com

Received 15 December 2008; revised 16 July 2009; accepted 26 August 2009

From first-principles, the electronic and elastic properties of alkali-metal sulphides (Li2S, Na2S), with emphasis on the plane-wave pseudopotential method and the inclusion of the non-linear core correction for exchange and correlation have been investigated. At ambient condition, these compounds are found to crystallize in cubic anti-fluorite structure. This method is found to describe the properties of these materials rather well. In most of the cases, obtained ground state properties are in good agreement with experimental and theoretical results. From the electronic structure calculations, we found that Li2S is indirect band gap semiconductor whereas Na2S is direct band gap semiconductor within local density approximation (LDA).

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 808-814

 

 

Screening current and dielectric parameters in dual QCD

 

Hemwati Nandan1,4, Nils M Bezares-Roder2 & H C Chandola3,4

1Centre for Theoretical Studies, Indian Institute of Technology, Kharagpur 721 302

2Institute for Theoretical Physics, University of Ulm, Ulm 890 69, Germany

3Department of Physics, Kumaun University, Nainital 263 001

4Department of Physics, University of Konstanz, Konstanz 78457, Germany

Received 4 December 2008; accepted 6 August 2009

The screening current mechanism and dual Meissner effect in the QCD vacuum have been studied in view of the action for a dual (magnetic) superconductor derivable from the Zwanziger’s two-potential formalism. The flux tube structure emerging as an artifact of screening current in the background of both the monopole and dyon condensation has been investigated. The magneto-statical representation of the flux tube has also been presented with the conditions which are necessary to form a tube. The dielectric parameters of dual QCD vacuum have been calculated and the size of the flux tube resulting from the monopole and dyon condensation is compared.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 815-822

 

 

Novel minimum-component universal filter and quadrature oscillator with electronic tuning property based on CCCDBAs

 

Worapong Tangsrirat

Faculty of Engineering, King Mongkut’s Institute of Technology Ladkrabang (KMITL), Chalongkrung Road
Ladkrabang, Bangkok 10520, Thailand

E-mail: drworapong@yahoo.com

Received 9 July 2009; revised 31 July 2009; accepted 13 August 2009

The novel current-tunable voltage-mode universal biquad filter and sinusoidal quadrature oscillator using only two current-controlled current differencing buffered amplifiers (CCCDBAs) and two capacitors without external passive resistors have been presented. The first proposed filter realizes all the five standard types of the biquadratic functions and provides independent electronic tuning of the natural angular frequency (wo) and the bandwidth (BW) through an external bias current of the CCCDBA. No critical component matching conditions are required. The second proposed oscillator generates two sinusoidal output voltages with 90° phase difference. Its oscillation condition and the oscillation frequency (wo) are tunable independently through adjusting the bias current of the CCCDBA. Both the proposed circuit configurations have a low component count, attractive active and passive sensitivities and suitability to integrated circuit implementation. PSPICE simulation results that confirm the theoretical prediction, are also given and discussed.

 

 

Indian Journal of Pure & Applied Physics

Vol. 47, November 2009, pp. 823-827

 

 

Experimental and numerical realization of higher order autonomous
Van der Pol-Duffing oscillator

 

V Balachandran1,* & G Kandiban2

1Department of Physics, A A Government Arts College, Musiri, Tiruchirappalli 621 201

2Department of Physics, Thanthai Hans Roever College, Perambalur 621 212

*E-mail: brsbala@rediffmail.com

Received 28 April 2009; revised 17 August 2009; accepted 9 September 2009

The application of the hyperchaotic dynamics will enhance the engineering system such as chaos based security of communication in information technology. Interest in such systems has been increasing. Some interesting phenomena of higher order autonomous Van der Pol-Duffing oscillator based on fifth order hyperchaotic circuit to improve secure communication have been studied in the present paper. This circuit, which is capable of realizing the behaviour of every member of the autonomous Van der Pol-Duffing family, consists of just six linear elements (resistor, inductors and capacitors) and a smooth cubic non-linearity. In this circuit, we can confirm period doubling routes to chaos and then to hyperchaos through boundary condition, when the system parameter varies. The hyperchaotic dynamics, characterized by broad band power spectrum, is presented to confirm the hyperchaotic nature of the oscillations of the circuit. This has been investigated extensively using laboratory experiments and numerical integration of the appropriate differential equations.