Indian Journal of Pure and Applied Physics

http://www.niscair.res.in

 

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VOLUME 40                                                      NUMBER 11                                                  NOVEMBER  2002

CODEN:IJOPAU 40(11) 759-840(2002)                                                                                                         ISSN: 0019-5596

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CONTENTS

 

Atomic and Molecular Physics

New hot bands in high resolution FTIR spectrum of 13C2H2

      K A Mohamed

765

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

Lens distortion correction by adjusting image of calibration target

      Yun-Long Lay & Chern-Sheng Lin*

 

770

Condensed Matter: Structure, Mechanical and Thermal Properties

Temperature dependence of strain associated with domain walls in martensitic phase transition
      from fcc to fct

      A Dogan, A Arslan* & Y Harvatoglu

 

 

775

Mechanism of superconductivity in Yb1-xCax(Ba0.8Sr0.2)2Cu3O6+d

      T S Anvekar, K R Priolkar, P R Sarode*, V N Kamat Dalal & A V Narlikar

780

Thermoacoustical studies of some iso-alcohols in cyclohexane with toluene

      K Ramesh & L Palaniappan*

828

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

La satellites in X-ray emission spectra of middle-Z elements

      S Poonia* & S N Soni

786

Exploring site occupancy effects of equal low concentrations of Zn and Fe dopants on
      order parameter fluctuations in Y123 bulk samples: A preliminary investigation

      U C Upreti* & A V Narlikar

 

795

Double relaxation phenomena of di-substituted benzenes and anilines in non-polar
      aprotic solvents under high frequency electric field

      K Dutta, A Karmakar, (Mrs) L Dutta, S K Sit & S Acharyya*

 

801

Study of Bax Sr1-x TiO3 mixed system

      Ashok Kumar*, U C Naithani & B S Semwal

831

Interdisicplinary Physics and Related Areas of Science and Technology

Pilot-type scientific experimental device using optical method and computer vision technology

      Chern-Sheng Lin

816

News Scan

The emerging technology of spintronics

      Poonam Bhatt

 

835

____________

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

 

 

Indian Journal of Pure & Applied Physics

Vol. 40, November  2002, pp. 765-769

New hot bands in high resolution FTIR spectrum of 13C2H2

K A Mohamed

Department of Physics, Aligarh Muslim University, Aligarh 202 002

Received 18 March 2002; revised 6 August 2002

The high resolution Fourier transform infrared spectrum of 13C2H2 shows several bands in the 3 µm region. Some bands were reported earlier (Indian J Pure Appl Phys, 38 (2000) 681). A few new hot bands have been identified and assigned. The line positions of these bands, the rotational constants and the centrifugal distortion constants of the upper and lower states involved in the transitions, and the effective l-doubling constants q4 and q5 have also been reported.

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 770-774

Lens distortion correction by adjusting image of
calibration target

Yun-Long Lay1& Chern-Sheng Lin2

1Department of Electronic Engineering, National Chin-Yi Institute of Technology, Taichung, Taiwan, ROC

2Department of Automatic Control Engineering, Feng Chia University. Taichung, Taiwan, ROC

Received 29 May 2002; accepted 19 August 2002

The dilemma of lens distortion in computer vision is a common and serious phenomenon, especially when a lens captures a wide-angle image or when an object is seized within a limited range. Using correction lens, phase plates or holographic gratings, mainly, makes the corrections. However, it is extremely difficult to accurately correct the distortion using attached optic components because the design of these components is complicated and commercially hard to attain.  In this paper,  a method is proposed to correct the distortion using the lens aberration theory and image processing techniques.  A calibration target is taken as the correct and acceptable objective.  The captured or seized image of the calibration target is not equally divided as original and this pixels-shift contains the distortion information which could be corrected by image process software produced by the authors.

Indian J Pure & Applied Physics

Vol. 40, November  2002, pp. 775-779

Temperature dependence of strain associated with domain walls in martensitic phase transition from fcc to fct

A Dogan, A Arslan* & Y Havvatoglu

KSU Fen-Edebiyat Fakultesi, Fizik Bolumu, 46100, K.Maras, Turkey

Received 27 June 2001; revised 22 January 2002; accepted 5 April 2002

In-Tl alloy undergoes a martensitic transition from fcc to fct and is treated by a phenomenological theory based on Landau’s theory of phase transitions. Analytic expressions concerning the temperature dependence of the strain associated with the domain walls observed in this type of alloys are given in the present study

 

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 780-785

Mechanism of superconductivity in Yb1-xCax(Ba0.8Sr0.2)2Cu3O6+d

T S Anvekar1, K R Priolkar1, P R Sarode1, V N Kamat Dalal2 & A V Narlikar3

1Department of Physics, Goa University, Taleigao Plateau, Goa 403 206

2Department of Chemistry, Goa University, Taleigao Plateau, Goa 403 206

3National Physical Laboratory, Dr K S Krishnan Marg, New Delhi 110 012

Received 5 September 2001; revised 7 August 2002; accepted 9 August 2002

EXAFS, X-ray Rietveld refinement and infra-red absorption measurements have been made on Yb1-xCax (Ba0.8Sr0.2)2 Cu3O6+d in order to understand the effect of Ca doping on the local structure of planar Cu ion. The study indicates that, restoration of superconductivity is due to oxidation of copper ions in the CuO2 planes.

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 828-830

Thermoacoustical studies of some iso-alcohols in cyclohexane with toluene

K Ramesh & L Palaniappan*

Department of Physics, *Department of Physics (D.D.E), Annamalai University, Annamalainagar  608 002

Received 29 May 2002; accepted 19 August 2002

The ultrasonic velocity, density and viscosity of 2-butanol in cyclohexane with toluene at 303 K have been experimentally measured and the same for 2-propanol system have been taken from literature. The thermoacoustical properties such as acoustic impedance, Rao’s constant, relative association and relaxation time are calculated. The results are interpreted in terms of molecular interaction between the components of the mixtures. The two systems are compared and it is observed that the interactions are very weak in 2-propanol system than in the other.

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 786-794

La satellites in X-ray emission spectra of middle-Z elements

S Poonia

Division - I, Central Arid Zone Research Institute, Jodhpur, Rajasthan 342 003

and

S N Soni

X-Ray Laboratory, Physics Department, Jai Narain Vyas University, Jodhpur 342 005

Received 1 February 2002; revised 18 June 2002; accepted 5 July 2002

The X-ray satellite spectra arising due to  (x º s, p, d) transition array, in elements with Z = 40 to 48, have been calculated. While the energies of various transitions of the array have been determined by using available Hartree-Fock-Slater data on and Auger transition energies and their relative intensities have been estimated by considering cross-sections of singly ionized  (x º s, p) states and then of subsequent Coster-Kronig and shake-off processes. The calculated spectra have been compared with the measured satellite energies in La spectra. Their intense peaks have been identified as the observed satellite lines. The one-to-one correspondence between the peaks in calculated spectra and the satellites in measured spectra has been established on the basis of the agreement between the separations in the peak energies and those in the measured satellite energies. It has been established that, three satellites observed in the La region of the X-ray spectra of various elements and named a3, a4 and a5 in order of increasing energy are mainly emitted by  transitions. It is observed that, the satellite a3 in all these spectra can be assigned to the super-position of 3F4-3F4 transition and that, this must be most intense one out of all these satellites, contributing in order of decreasing intensity. The line a4, has been assigned mainly to the 1F3-1G4 and 3P0-3P1 transitions. Finally, the satellite a5, reported in the spectra of elements with Z= 40-48, has been associated with the transitions 3D3-3F4, 3D2-3F3, 1P1-1D2 and 1F3-1D2. The possible contributions of other transitions of the  (x º s, p, d) array having appreciable intensities, have also been discussed.

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 795-800

Exploring the site occupancy effects of equal low concentrations of Zn and Fe dopants on order parameter fluctuations in Y123 bulk samples: A preliminary investigation

U C Upreti & A V Narlikar

National Physical Laboratory, New Delhi 110 012

Received 27 March 2002; accepted 12 July 2002

In this preliminary exploratory investigation report, the authors look for and compare, mainly in the mean-field-region (MFR), the effects, if any, on order parameter dimensionality (OPD) and excess conductivity (Ds) due to separate equal (0.5%) low-concentration substitutions of Zn and Fe at the Cu-sites in Y123 polycrystalline bulk superconductor samples. The OPD dependence on change of Cu-site low disorder dopant and the effects of OPD variation on the interlayer coupling, on its cross-over behaviour, on superconductivity suppression and anisotropy are discussed. It is seen that the OPD increases by Fe doping but is independent of intrinsic disorder in pure as well as in the Fe doped sample. The system anisotropy is invariant to (raised with) Zn (Fe) low disorder. In pure and Zn doped samples, the dimensionality behaviour enables us to estimate the c-direction coherence length (xc) and consequently, the Josephson coupling strength (J). At these doping levels, there is no significant change in J due to Zn, whereas the OPD behaviour in Fe doped sample does not allow us to estimate xc and J.

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 801-815

Double relaxation phenomena of di-substituted benzenes and anilines in non-polar aprotic solvents under high frequency electric field

K Dutta , A Karmakar, (Mrs) L Dutta, S K Sit & S Acharyya

Department of Physics, Raiganj College (University College), PO Raiganj Dist, Uttar Dinajpur 733 134

[e-mail: koushikduttajsm@rediffmail.com]

Received 1 October 2001; revised 12 February 2002; accepted 15 April 2002

The derived linear equation (coij - cij¢)/cij¢ = w(t1+t2) cij²/cij¢ - w2t1t2 for different weight fractions wj of di-substituted benzenes and anilines (j) in aprotic and non-polar solvents (i) C6H6 and CCl4 under 9.945 GHz electric field are obtained from the available measured dielectric relative permittivities at 35 °C. The double relaxation times t1 and t2 of the flexible part and the whole molecule are estimated from the slope and intercept of the above equation. cij¢ and cij² are the real and imaginary parts of the high frequency complex orientational dielectric susceptibility cij* and coij is the low frequency dielectric susceptibility, which is real. They are, however, related with the measured relative permittivities. Values of tj are calculated from the ratio of the individual slopes of the variations of cij² and cij¢ with wj at wj®0, assuming single Debye-like dispersion and compared with Murthy et al. [Indian J Phys, 63B (1989) 491] and Gopalakrishna [Trans Faraday Soc, 53 (1957) 767]. The weighted contributions c1 and c2 towards dielectric relaxations for t1 and t2 can, however, be obtained from Fröhlich’s theoretical formulations of cij¢/coij and cij²/coij and compared with those from the experimentally measured values of (cij¢/coij)wj®0 and (cij²/coij)wj®0. The latter measured values are employed to get symmetric distribution parameter g to yield symmetric relaxation time ts. The curve of (1/f) log(cos f) against f in degrees together with the values of (cij¢/coij)wj®0 and (cij²/coij )wj®0 experimentally obtained, gives the asymmetric distribution parameter d to get the characteristic relaxation time tcs. All these findings ultimately establish the different types of relaxation behaviour for such complex molecules. The dipole moments m1 and m2 for the flexible part and the whole molecule are ascertained from t1 and t2 and the linear coefficients b1 of cij¢ versus wj and b2 of sij versus wj curves respectively, where sij is the hf conductivity. The values of m are finally compared with the reported m’s and mtheo’s derived from available bond angles and bond moments of the substituted polar groups of di-substituted anilines to conclude that a part of the molecule is rotating while the whole molecular rotation occurs for di-substituted benzenes. The slight disagreement between measured values of m and mtheo can, however, be interpreted by the inductive, mesomeric and electromeric effects of the polar groups of the parent molecules.

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 831-834

Study of BaxSr1-xTiO3 mixed system

Ashok Kumar, U C Naithani & B S Semwal

Department of Physics, Garhwal University, Pauri Campus, Pauri (Garhwal)

Received 3 October 2001; revised 7 January 2002;

accepted 8 August 2002

In the present study, the pellets of BaxSr1-xTiO3 using solid solution reaction method have been prepared. The prepared samples have been characterized using X-ray diffraction method and grain size have been found using SEM photographs. The loss tangent of these materials has been measured in para-electric phase. The temperature, frequency and concentration dependences of dielectric properties have been studied. Apart from experimental study on BaxSr1-xTiO3, the parameters a,b,g by using the empirical formula [(T-Tc) tand=w(a+bT+gT2)] for different values of x in BaxSr1-xTiO3 have been calculated. The results have been compared with the previous experimental and theoretical results.

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 816-827

Pilot-type scientific experimental device using
optical method and computer vision technology

Chern-Sheng Lin

Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan

Received 5 February 2002; revised 15 May 2002; accepted 19 August 2002

Digital image and multimedia technology projected in a modified laser shadow spot set-up to guide people to engage in the scientific model of the crack growth has been described. This novel device can be operated automatically, and economically in a participating display. A new method to process the experimental data and predict the fracture time in the PC-based digital signal processing system has been developed. With one video CCD camera and frame grabber analyzing a series of images of laser shadow spot during crack growth, the computers obtain the image size of laser shadow spot to evaluate stress intensity factor in real time. An auto-range finding algorithm is used to find the location of a laser shadow spot. Six special experimental conditions have been considered to improve this scientific model. Participants can operate the model themselves, so that they can observe the change of sizes of the laser shadow spot images and can respond in time to know the status of specimen in tension. It also can remind the attention of the participant with the sign of a speech sound before the break of specimen to achieve the effect during recreation to learn.

 

Indian Journal of Pure & Applied Physics

Vol. 40, November 2002, pp. 835-836

News Scan

The emerging technology of spintronics

Every appliance from electric bulb to laptop computer works on the principle of transport of electrical charge carriers—electrons, which cause electric current to flow through wires. The electrons have both charge and spin. The spin of the electrons could greatly enhance the particles' usefulness. The semiconductor technology is based on the number of charges and their energy. The electronic devices such as transistors work due to flow of charge. The electron can be assumed as tiny rotating bar magnet with two possible orientations: spin–up or spin-down. An applied magnetic field can flip electrons from one state to another. In this way, spin can be measured and manipulated to represent the 0's and 1's of digital programming, analogous to the “current on and current off” states in a conventional silicon chip. The study of electron spin in materials is called Spintronics. Spintronics is based on the direction of spin and spin-coupling (Nature, April, 2002)