Indian Journal of Pure and Applied Physics

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Volume 45                                                      Number 5                                      MAY 2007

CODEN : IJOPAU 45 (5) 415- 486                                                                   ISSN : 0019-5596

 

 

CONTENTS

 

Nuclear Physics

 

Study of multidimensional fluctuations and non-thermal phase transition in ring like and jet like events in ultrarelativistic nuclear collisions

419

Dipak Ghosh*, Argha Deb, Prabir Kumar Haldar & Sima Guptaroy

 

Measurement of excitation functions of the reactions 58Ni(n,2n)57Ni and 65Cu(n,2n)64Cu in the neutron energy range 13.90–14.71 MeV

425

M A Hafiz

 

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

 

Schlieren interferometric concealed coded security holograms

429

Raj Kumar & A K Aggarwal*

 

Ultrasonic attenuation in liquid mercury, zinc and gallium metals

434

O N Awasthi & V K Pundhir*

 

Estimation of electro-optical payload performance

437

R K Mishra*, Kasi Vishweswara Rao, V Vamshi Krishna & A M G Pillai

 

Condensed Matter: Structure, Mechanical and Thermal Properties

 

Structural and optical studies of activated thin film and monolith nano-structure silica gel with different rare earth elements prepared by sol-gel techniques

441

I K Battisha*, A El Beyally, S L Soliman  & A M S Nahrawi

 

Heating of manganites by magnetic component of microwave

454

R J Singh

 

High-pressure behaviour of rare earth mono bismuthides

459

Gitanjali Pagare, Sankar P Sanyal* & P K Jha

 

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

 

Effect of substrate temperatures, deposition rate and heat treatment on structural and carrier transport mechanisms of thermal evaporated p-Cu2S/n-CdS heterojunction

465

M M El Nahass & A M A El-Barry*

 

Dielectric relaxation of poly ethylene glycol-water mixtures using time domain technique

476

C S Mali, S D Chavan, K S Kanse, A C Kumbharkhane & S C Mehrotra*

 

 

___________

*The corresponding author has been indicated by (*) mark in case of papers with more than one author.


 

 

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 419-424

Study of multidimensional fluctuations and non-thermal phase transition in ring like and jet like events in ultrarelativistic nuclear collisions

 

Dipak Ghosh, Argha Deb, Prabir Kumar Haldar1 & Sima Guptaroy2

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

E-mail: dipakghosh_in@yahoo.com

Received 17 May 2006; revised 18 October 2006; accepted 13 February 2007

Non-thermal phase transition for ring like and jet like events for pions produced in 32S-AgBr interactions at 200 A GeV has been studied. The study has been performed in the frame work of two-dimensional factorial moment methodology using the concept of Hurst exponent (H) to take care of anisotropic phase-space. An indication of non-thermal phase transition in jet like events only is revealed by the data.

Keywords: Non-thermal phase transition; Ultra-relativistic nucleus-nucleus collisions, Fluctuations , Self-affinity, Self-similarity, Ring like events , Jet like events

IPC Code: G01T

 

 

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 425-428

 

Measurement of excitation functions of the reactions 58Ni(n,2n)57Ni and 65Cu(n,2n)64Cu in the neutron energy range 13.90-14.71 MeV

 

M A Hafiz

Institute of Nuclear Science & Technology, Atomic Energy Research Establishment, GPO Box 3787, Dhaka, Bangladesh

E-mail: hafizmab@yahoo.com

Received 19 April 2006; revised 17 November 2006; accepted 8 March 2007

Excitation functions of the reactions 58Ni(n,2n)57Ni and 65Cu(n,2n)64Cu in the neutron energy range 13.90-14.70 MeV have been measured using activation technique. Neutrons were produced via D-T reaction using solid tritium target at J-25 neutron generator of the Institute of Nuclear Science and Technology (INST), Savar, Dhaka, Bangladesh, with deuteron energy of 110 keV and beam current of ~120 mA. Activities of the reaction products have been measured using HPGe detector gamma-ray spectrometry system. Neutron flux at each sample position was determined by using the monitor reaction 27Al(n,a)24Na. Uncertainties in the measured cross-section values include statistical and systematic errors. Theoretical cross-sections were calculated using computer code SINCROS-II. Measured cross-section values fit fairly well with the literature data and lie within 24.71±4.07 to 38.84±4.82 mb for the 58Ni(n,2n)57Ni and 826.0±62.4 to 960.7±63.2 mb for the 65Cu(n,2n)64Cu reactions, respectively. SINCROS-II values are about 1.1 times the measured values for both the cases.

Keywords: Reaction cross-section, Activation, Neutron generator, Fusion technology

IPC Code: G21B

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 429-433

 

Schlieren interferometric concealed coded security holograms

 

Raj Kumar & A K Aggarwal*

Coherent Optics Division, Central Scientific Instruments Organisation, Sector 30, Chandigarh 160 030

*E-mail: aka1945@rediffmail.com

Received 18 January 2007; accepted 16 March 2007

A method has been described to create concealed codes in security holograms. The codes are in the form of pure phase patterns and require an interferometric scheme to convert these invisible phase variations into detectable amplitude/intensity variations. An interferometrically encoded reference beam from the key hologram captures a phase modulated object beam to form the security hologram. In the final reading process, a moiré-like fringe pattern gets generated in the observation plane when the same reference beam illuminates security hologram. This moiré pattern is helpful in verifying the genuineness of the hologram and also facilitates in repositioning of security hologram. In the null mode moiré position, true object wavefront gets reconstructed but the information of concealed codes still remains invisible. Use of schlieren technique is proposed as a simple way to reveal the concealed codes for security hologram authentication. These concealed codes can be used as an anti-counterfeiting feature in embossed security holograms.

Keywords: Optical security, Authenticity verification, Security hologram, Schlieren techniques

IPC Code: G03H

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 434-436

 

 

Ultrasonic attenuation in liquid mercury, zinc and gallium metals

 

O N Awasthi1 & V K Pundhir2

Department of Physics, Regional Institute of Education, National Council of Educational Research & Training,
Bhopal 462 013, Madhya Pradesh

E-mail: 1omnarain_awasthi@yahoo.co.in; 2vivekpundhir@yahoo.com

Received 20 March 2006; revised 24 January 2007; accepted 19 March 2007

Ultrasonic attenuation in mercury, zinc and gallium metals has been studied using the concept of a two-state thermodynamical model for the liquids near the melting points. Our theoretical results, so obtained, have been compared with the experimental values and necessary explanations have been offered for any deviations in the results.

Keywords: Liquid metals, Ultrasonic relaxation, Transport properties, Ultrasonic attenuation

IPC Code: B06B

 

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 437-440

Estimation of electro-optical payload performance

 

R K Mishra*, Kasi Vishweswara Rao, V Vamshi Krishna & AMG Pillai

Aeronautical Development Establishment, CV Raman Nagar, Bangalore 560 075

Received 3 July 2006; accepted 16 March 2007

Evaluation of the performance of electro-optical payload within the laboratory is discussed. This method is valid for the system, which has output in the form of electrical signal though the input is optical in nature. The methodology enables the evaluation of entire configuration of electro-optical payload comprising of lens system, photo detecting device (one or two dimension array) and processing electronics. The data collected can also be utilized to compute different parameters to estimate National image interpretability rating scale of payload.

Keywords: Electro-optical, Payloads, Payload resolution, Payload performance evaluation, National image interpretability rating scale

IPC Code: H02G

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp 441-453

 

Structural and optical studies of activated thin film and monolith nano-structure silica gel with different rare earth elements prepared by sol - gel techniques

I K Battisha*, A El Beyally**, S L Soliman** & A M S Nahrawi

*National Research Center, Department of Solid Satate Physics, Guiza, Egypt

**Faculty of Women Ain Sahms University, Physics Department Cairo, Egypt

*E-mail: szbasha@yahoo.com

Received 28 February 2006; revised 20 November 2006; accepted 14 February 2007

Rare earth (Pr+3, Eu+3, Er+3 and Ho+3 ions) doped silica gel with different concentrations in the range 1-6% of each element, in the form of thin film and monolith materials have been studied by X-ray diffraction (XRD). The types of structural information obtainable have been compared in detail. The XRD spectra of a-crystobalite are obtained for the two type of materials and even by doping with the four rare earth element (REEs) at higher sintering heat treatment temperature. The structure study revealed that the crystallite size of pure monolith nano-structure silica gel was about 20.9 nm sintered at 1200°C, which decreased to 12.1 nm by doping with 6% of holmium ions at the same temperature. Optical measurements of both type of materials were also studied and compared. The normal transmission and specular reflection were measured. The coarse and fine microstructures of the monolith and thin film prepared samples were depicted by transmission electron microscope (TEM), which revealed the presence of nano-structure scale in the prepared samples, confirming the data obtained from XRD.

Keywords: Thin film, Monolith nano-structure silica gel, Rare earth element

IPC Code: B82B

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 454-458

 

Heating of manganites by magnetic component of microwave

R J Singh

Department of Physics, Aligarh Muslim University, Aligarh 202 002

E -mail: ranajsingh@yahoo.com

Received 18 July 2005; revised 4 December 2006; accepted 8 January 2007

When the dependence of EPR spectra of La0.67 Pb0.33 MnO3 , La0.6Pb0.4 MnO3 , La0.7 Ba.3 MnO 3 and La0.67 Sr0.33 MnO3 on microwave power (1-200mW) applied in the EPR instrument was investigated, it was observed that the samples became unusually hot on high microwave power levels. The cause of heat generation has been explained as interaction of the spin of eg electron of Mn3+ with the magnetic component of microwave field which ultimately leads to Debye type of relaxation of a physical ensemble ,i.e., spin-orbital-lattice polaron . The polaron so created is found to be of 11 Å size and consists of Mn3+ ion, its nearest neighbours Mn4+ and La3+ ions and the alkaline earth ions along with oxygen octahedra surrounding Mn-ion sites.

Keywords: Manganites, Electron paramagnetic resonance, Microwave heating

IPC Code: G01R27/02; H01F1/00

 

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 459-464

 

High-pressure behaviour of rare earth mono bismuthides

Gitanjali Pagare1,2, Sankar P Sanyal2 &  P K Jha3

1Government M L  B  Girls P G College, Bhopal 462 011

2Condensed Matter Physics Laboratory, Department of Physics, Barkatullah University, Bhopal 462 026

3 Department of Physics, M S University of Baroda, Vadodra 390 002

2E-mail: spsanyal@sancharnet.in

Received 1 March 2006; revised 19 December 2006; accepted 4 January 2007

Pressure induced structural phase transition of mono-bismuthides of cerium,  praseodymium, uranium and plutonium  (REBi, RE= Ce, Pr, U and Pu) has been studied theoretically by using suitable two body inter-ionic potential which parametrically includes the effect of Coulomb screening by the delocalized f electrons of rare earth (RE) ion. The anomalous structural properties of these bismuthides, where Bi ion has the largest ionic radius, have been studied to investigate the role of f electrons on the structural phase transition. Except UBi, all the three compounds transform to body -centered tetragonal (BCT) structure at high pressure. UBi prefers to transform  to cubic CsCl phase at high pressure. A static simulation technique has been used to calculate the equation of state, change in anion-anion and anion-cation distances with increasing pressure, for these compounds. The important finding is that, from the total energy point of view except UBi, all the compounds prefer to transform to BCT structure than CsCl structure at high pressure.

Keywords: Phase transition, Tetragonal phase, Coulomb screening, Pnictides

IPC Code: G12B

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp 465-475

 

Effect of substrate temperatures, deposition rate and heat treatment on
structural and carrier transport mechanisms of thermal evaporated
p-Cu2S/n-CdS heterojunction

M M El Nahass & A M A El-Barry*

Physics Department, Faculty of Education, Ain Shams University, Cairo, Egypt

*E-mail:elsevier56@yahoo.com

Received 19 October 2005; revised 13 November 2006; accepted 14 February 2007

The p-Cu2S/n-CdS heterojunction (Hj) has been fabricated by vacuum deposition of p-Cu2S thin film onto n-CdS thin film. CdS layer was evaporated at substrate temperature, Ts ˜ 473 K and rate of deposition ˜0.06 µm/min. The dark-temperature-current density-voltage (J-V-T) and illumination characteristics were measured over a reasonable temperature range (303-423K). The conduction mechanism was suggested to be thermo ionic for forward applied voltage < 0.2V. For higher voltage, the space charge limited current was the predominant mechanism. In the reverse direction, the generation and recombination mechanisms were the operating mechanisms. Finally, the photovoltaic characteristics and the spectral response of p-Cu2S/n-CdS were also studied .

Keywords: Cu2S/CdS heterojunction, Thin film, Ilumination, Space charge limited current, Photovoltaic characteristics, Spectral response

IPC Code: H01L

 

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 45, May 2007, pp. 476-481

 

 

Dielectric relaxation of poly ethylene glycol-water mixtures
using time domain technique

 

C S Mali, S D Chavan, K S Kanse, A C Kumbharkhane & S C Mehrotra

School of Physical Sciences, Swami Ramanand Teerth Marathwada, University, Vishnupuri, Nanded 431 606

Department of Computer Science and Information Technology, Dr B A M

University, Aurangabad 431 004

Email: akumbharkhane@yahoo.co.in

Received 23 November 2005; revised 18 July 2006; accepted 5 February 2007

Complex dielectric measurements in the frequency range 10 MHz-20 GHz have been carried out in poly ethylene glycol- water mixtures with various concentrations using Time Domain Reflectometry (TDR) method at 25°C. The dielectric dispersion spectra could be fitted with a single relaxation time with Davidson-Cole behaviour at low volume fraction of water. However, at higher volume fraction of water in poly ethylene glycol dielectric dispersion spectra can be fitted with the Debye behaviour. The values of static dielectric constant, relaxation time, distribution parameter, Bruggeman factor and Kirkwood correlation factor have been determined for the poly ethylene glycol-water system. The study confirms that the intermolecular homogeneous and heterogeneous hydrogen bonding vary significantly with the increase in concentration of poly ethylene glycols in aqueous solutions.

Keywords: Dielectric permittivity, Loss and relaxation time, Time domain reflectrometry

IPc Code: G01R27/26