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Indian Journal of Pure and Applied Physics

 

 ISSN: 0019-5596

CODEN: IJOPAU 42 (3) 153-234

Volume 42

Number 3

March 2004

 

  CONTENTS

Nuclear Physics

 

 

Radiological impact of airborne radon and its progeny in dwellings

K Kant* & S K Chakarvarti     

157

 

 

Atomic and Molecular Physics

 

 

 

Vibrational spectra and molecular structural investigation of quiniodochlor 

S Gunasekaran*, U Ponnambalam, S Muthu & G Anand

162

 

 

Effect of the interatomic potentials on the broadening and shifting of the intercombination spectral lines of Hg, Cd and Zn by inert gases

G D Roston                  

167

 

 

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

 

Ultrasonic velocity and allied parameters of symmetrical tetra-alkyl ammonium bromides in aqueous ethanol at 298.15K

P S Nikam, Mehdi Hasan*, T B Pawar & A B Sawant

172

 

 

Condensed Matter: Structure, Mechanical and Thermal Properties

 

 

 

Study of temperature dependent gas permeability for polycarbonate membrane       

N K Acharya*, P K Yadav & Y K Vijay                                 

179

 

 

Design and development of microcontroller based conductivity measurement system    

A Rajendran* & P Neelamegam                                                      

182

 

 

Surface morphology of gall bladder stones

V R Singh* & Palwinder Kaur

189

 

 

Zn content variation effect on excess conductivity, superconducting order parameter dimensionality and interlayer coupling in ErBa2Cu3-xZnxO7-8

U C Upreti

195

 

 

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

 

 

 

Optical and electrical properties of indium-tin oxide films

K Narasimha Rao                                            

201

 

 

Effective mass calculation for Inse, Inse:Ho0.0025, Inse:Ho0.025, InSe:Ho0.005 and InSe:Ho0.05 samples using the external electric field shifting

Aytunç ATES  

205

 

 

Modelling of threshold voltage adjustment in fully depleted double gate (DG) SOI MOSFETs in volume inversion to quantify requirements of gate materials

Abhinav Kranti, Rashmi, S Haldar & R S Gupta*

211

 

 

Magnetic, dielectric and microwave absorption studies of Ba-CoTi hexaferrite – Epoxy composites

Praveen Singh*, V K Babbar, Archana Razdan, T C Goel & S L Srivastava        

221

 

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

 

 

 

 Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 157-161

 

Radiological impact of airborne radon and its progeny in dwellings

K Kanta & S K Chakarvarti

 

Measurement of indoor radon and its progeny levels was carried out in some typical dwellings made up of baked mud bricks, fly ash bricks, concrete blocks and mud houses using LR-115, Type II plastic track detectors in various districts of Haryana. The Potential Alpha Energy Concentration (PAEC) varied from 4.36 to14.53 mWL; Equilibrium Equivalent Concentration (EEC) of radon varied from 40.33 to 134.40 Bq m-3; annual exposure varied from 0.18 to 0.60 WLM; annual effective dose varied from 0.69 to 2.31 mSv and life-time fatality risk varied from 0.54 ´10-4 to 1.8 ´10-4 in the environment of dwellings in various districts of Haryana. The effect of various parameters on radon concentration such as seasonal variation and type of building materials was also studied. The radon concentration in industrially polluted cities like Faridabad, Panipat, Rewari, Yamun Nagar was found to be more. The measured radon and its progeny levels were the highest in winter season. In the measurements, we found that radon concentration was the maximum in fly ash houses.

 

[Key words: Radon, Radiological impact, Calibration, Fly ash, Solid State Nuclear Track Detector]

IPC Code: G21C 14/104

 

   

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 162-166

 

Vibrational spectra and molecular structural investigation of quiniodochlor

S Gunasekaran, U Ponnambalam*, S Muthu* & G Anand+

 

A normal coordinate analysis on quiniodochlor has been carried out with a systematic set of symmetry coordinates following Wilson's F-G Matrix method. The potential constants evaluated for the molecule are found to be in good agreement with literature values thereby confirming the vibrational assignments. To check whether the chosen set of vibrational frequencies contribute maximum to be potential energy associated with the normal coordinates of the molecule, the potential energy distribution has been evaluated.

 

[Keywords: Normal coordinate analysis, vibrational spectra, quiniodochlor, F-G Matrix.]

IPC Code: G 01J 3/44

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 167-171

 

Effect of the interatomic potentials on the broadening and shifting of the intercombination spectral lines of Hg, Cd and Zn by inert gases

G D Roston

 

The Van der Waals and Lennard-Jones potential parameters for the ground and exited states of the second group elements (Hg, Cd and Zn) perturbed by inert gases (Xe, Kr, Ar, Ne and He) have been calculated using coulomb approximation. The basis of the Lindholm-Foley impact theory and the calculated potential parameters are used for calculating the collision broadening and shift coefficients b and d for the intercombination lines 253.7, 326.1 and 307.6 nm of Hg, Cd and Zn atoms respectively, when they are colliding with inert gas atoms. The calculating coefficients of b and d are compared with their corresponding experimental values, taken from literatures.

 

[Keywords: Interatomic potentials, spectral lines, inert gases]

IPC Code: G 01J 3/30

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 172-178

 

Ultrasonic velocity and allied parameters of symmetrical
tetraalkyl ammonium bromides in aqueous ethanol at 298.15 K

P S Nikam1, Mehdi Hasan1*, T B Pawar2 & A B Sawant1

 

Ultrasonic velocities in solutions of tetraalkyl ammonium bromide, R4NBr (R = CH3 through n-C4H9), NaBPh4 and NaBr in ethanol-water mixtures were measured at 298.15 K by using a single-crystal interferometer at a frequency of 2 MHz. The ultrasonic velocity, density and concentration were used to calculate adiabatic compressibility, apparent molar compressibility, intermolecular free length, specific acoustic impedance, relative association and solvation number. Bachem and Gucker's laws have been found to be valid.

 

[Keywords: Ultrasonic velocities, symmetrical tetraalkyl ammonium bromides, apparent molar compressibility]

IPC Code: G 01D

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 179-181

 

Study of temperature dependent gas permeability for polycarbonate membrane

N K Acharya, P K Yadav & Y K Vijay*

 

A polycarbonate membrane of thickness 30 (±2) μm was prepared by solution cast method for the present study. The gas permeability measured as a function of pressure as well as temperature for the membrane. The permeability measurements in the pressure range 30-100 psi at room temperature do not show any remarkable change for H2, but considerable changes in permeability in the temperature range 303-371 K at 30 psi has been observed for both the gases H2 and CO2.

 

Keywords: Polycarbonate membrane, gas permeabiulity, thermal properties

IPC Code: G 01L 13/04

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 182-188

 

Design and development of microcontroller based conductivity measurement system

A Rajendran and P Neelamegam

 

A real time microcontroller based conductivity measurement setup has been developed to measure conductivity by investigating ionic solutions using a modified AC Wheatstone bridge network. This instrument system permits recording of conductivity and temperature and send data to personal computer to enable the computer processing of such data. A dedicated 8031(8-bit) based microcontroller board was employed for the hardware. The details of its interface to measure conductivity, temperature and to control the temperature and evaluate results are explained in this paper.

 

[Keywords: Conductivity measurement, Temperature measurement, Data acquisition system, Microcontroller, Electrolytic solutions, Ionic solutions, Current-carrying ions]

IPC Code: G01H 25/20

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 189-194

 

Surface morphology of gall bladder stones

V R Singh & Palwinder Kaur

 

Gall bladder stones are crystalline structures formed by concretion or accretion of normal or abnormal bile constitutents. These stones are normally made of cholesterol, calcium, phosphate, carbonate and proteins. The aetiology of gall bladder stones is multifactoral. Scanning electron microsscopy (SEM) is used here to investigate the surface features of the mechanically fractured part of the stone samples. Micrographs exhibit a non uniform polycrystalline surface without specific grain boundaries with porosity, leading to loose bounding of crystals and hence low specific gravity. These results pertaining to surface characterisation are very useful for understanding the disintegration process of stones inside or outside the human body.

 

[Keywords: Gall bladder stones, Morphology, Surface morphology, Disintegration process]

IPC Code: G 01N 13/10

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 195-200

 

Zn content variation effect on excess conductivity, superconducting order
parameter dimensionality and interlayer coupling in ErBa2Cu3-xZnxO7-d

U C Upreti

 

Zn concentration variation effects on superconducting order parameter fluctuations are compared in ErBa2Cu3-xZnxO7-d polycrystalline bulk samples for x=0.0, 0.03, 0.05, 0.12, and 0.18; perhaps as a first ever study. The SCOPF in pure and Zn doped samples are 3D. Zn seems to cause suppression of 2D fluctuations. SCOPF dimensionality shows independence from carrier concentration variation due to Zn in the planes and also suggests strong coupling between two nearest CuO2 planes in the unit cells in pure and Zn doped sam­ples. Fluctuations remain almost invariant to Zn doping vis-à-vis the pure sample.

 

[Keywords: Excess conductivity, fluctuations, superconducting order parameter, Interlayer coupling, carrier concentration, Polycrystalline bulk samples, Zn doped samples]

IPC Code: H 01L 39/24

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 201-204

 

Optical and electrical properties of indium-tin oxide films

K Narasimha Rao

 

Indium-tin oxide films find several applications because of their excellent properties such as high optical transparency, good electrical conductivity, high infrared reflectance etc. Achieving these properties depend on the choice of the deposition technique and the control of process parameters. It is all the more beneficial if these properties are to be realized at ambient temperature and without post deposition heating. In this investigation, indium-tin oxide films have been deposited by reactive electron beam evaporation of In+Sn alloy both in neutral and ionized oxygen environments. A low energy ion source has been used to ionize oxygen. Films deposited with neutral oxygen exhibited very low optical transmittance (5% at 550nm). Highly transparent (90%) and low resistivity (5´10-4 ohm cm) films have been deposited on glass in ionized oxygen at ambient substrate temperature. As deposited films on ambient substrate with very low resistivity obtained by evaporation, are very significant.

 

[Keywords: Optical properties, Indium tin oxide films, electrical properties]

IPC Code: C01G

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 205-210

 

Effective mass calculation for InSe, InSe:Ho0.0025, InSe:Ho0.025,
InSe:Ho0.005 and InSe:Ho0.05 samples using
the external electric field shifting

Aytunç ATEŞ

 

Undoped InSe and Ho doped InSe single crystals were grown by Bridgman-Stockberger method. The InSe crystals both undoped and doped with different ratios of  (InSe:Ho0.0025, InSe:Ho0.025, InSe:Ho0.005 and InSe:Ho0.05) had no cracks or voids on the surface. No polishing or cleaning treatments were carried out on the cleaved faces of these samples because of the natural mirror-like cleavage faces. The absorption measurements were carried out in the temperature range 10-320 K and the external electric field effect on the absorption measurements was investigated. The absorption edge shifted towards the longer wavelengths under an electric field as  6 kV/cm. Using the electric field shits, effective mass values are calculated for all the samples.

 

[Keywords: InSe single crystal, absorption, exciton binding energy, Holmium doping]

IPC Code: H 01L 27/04

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 211-220

 

Modelling of threshold voltage adjustment in fully depleted double gate (DG) SOI MOSFETs in volume inversion to quantify requirements of gate materials

Abhinav Kranti, Rashmi, S Haldar1 & R S Gupta

 

An analytical model is developed for volume inversion in DG SOI MOSFETs to study the impact of silicon film thickness, work function difference between gate and substrate, and gate voltage on electric potential, electron density and sheet density of mobile charges. The proposed model is extended to predict the threshold voltage of devices with different gate materials and quantifies the gate material requirements of symmetric self-aligned DG MOSFETs. A limiting criterion is developed on doping level and film thickness to ensure the occurrence of volume inversion in fully depleted DG SOI MOSFETs. Close proximity with simulated results confirms the validity of the present model.

 

[Keywords: Double Gate SOI MOSFET, Threshold voltage adjustment, Gate materials, Volume inversion, SOI MOSFET, MOSFET]

IPC Code: G 01R 3/00

 

 

Indian Journal of Pure & Applied Physics

Vol. 42, March 2004, pp 221-228

 

Magnetic, dielectric and microwave absorption studies of
Ba-CoTi hexaferrite ¾ Epoxy composites

Praveen Singh*#, V K Babbar**, Archana Razdan**, T C Goel* & S L Srivastava***

 

The microwave absorption, complex permittivity and complex permeability studies of hexaferrite composites prepared with Ba(CoTi)xFe12-2xO19 wherein x varies from 0.0 to 1.0 in steps of 0.2 were made in frequency range from 8.0 to 12.4 GHz. The effect of Co2+Ti4+ substitution and of microstructural variation on complex permeability, permittivity and microwave absorption have been analysed. The hexaferrite-composites with x > 0.0 exhibit significant dispersion in the complex permittivity (er¢- jer²) with maximum value of er² is observed for x equal to 1.0. The dispersion in complex permeability (mr¢-jmr ²) is not significant and is attributed to the shielding effect of polymer matrix over the ferrite crystallites and to the low alternating electromagnetic field applied to the sample. The variation of reflection loss has been studied as a function of frequency (f), Co2+Ti4+content and thickness of the absorber. A maximum absorption of 16 dB (86%) is obtained for composites with x equal to 0.4 and of 2.8 mm thickness.

 

[Keywords: Microwave absorption, Complex permeability, Complex permittivity, Microwave ferrite composites]

IPC Code: G 01N 25/00, 21/00