Vol 10 No 3

Asian Journal of Physics

Vol 10, No 3 (2001) 303-454

(An International Quarterly Research Journal of Physics)
(A Non-Profitable Registered Publication)

CONTENTS

Quantum mechanics on a lattice

F T Lee 303

Monitoring of ozone, water vapour etc during the voyage to Antarctica

S L Jain 315

Investigations on atmospheric humidity profile at varying oxygen levels with a laser based monitoring system

D Das, G A Ahmad, G K D Mazumdar and A Choudhury 323

Experimental study of 2D turbulence in soap films

K Pal and S Chopra 331

The electronic absorption spectra of four disubstituted phenols

R Kanna Rao, A Srinivasa Rao and D V Krishna Rao 337

Study of microstrip antennas using different materials

S N Mulgi, R M Vani, P V Hunagund and Sara Fatima Farida 355

Lattice dynamics of TAC and HFC using three-body force shell model

S Mohan and K Sonamuthu 359

Phase transitions in solid solutions of alloy semiconductors : Ga_1-x, In_xSb and Ga_1-x In_xP

Sadhna Singh 363

Latitudinal dependence of solar wind speed and the sunspot cycle

T E Girish and G Gopkumar . 369

A non linear impurity in two-dimensional systems

R S Roy 375

Comparative study of Forbush decrease with geomagnetic storm sudden commencement

P L Verma and S K Nigam 379

High frequency dielectric behaviour of erbium substituted Ni-Zn ferrites

K Vijaya Kumar and D Ravinder 391

Relationship among various interplanetary indices during maximum and minimum solar activity

G N Singh and Pankaj Kumar Shrivastava 397

A relation between cosmic rays and Dst field

M Lal and Pankaj K Srivastava 403

Studies on coronal mass ejections classified according to their speeds

T K Das and MK Ghosh 409

Influence of pressure on cosmic ray intensity at neutron monitor energies.

G.N Singh and Pankaj Kumar Srivastava 417

On the crystallographic aspects of some naturally occurring simple and furano coumarins

Rajnikant, V K Gupta, Dinesh and Mousmi Bhat 421

Single crystal growth and X-ray crystallograhphic analysis of some 4, 4'-substituted biphenyls

Rajnikant, V K Gupta, A Kumar, R Gupta, A Kumar, Dinesh and Ashu Sawhney 431

Conformational analysis of some steroidal molecules

Rajnikant, V K Gupta, Dinesh and Mousmi Bhat 439

Thermal and FTIR spectroscopic studies of aspirin single crystal

Sanjay P Vachhani, R M Dabhi and M J Joshi 447

Asian Journal of Physics Vol 10, No 3 (2001)323-330

Investigations on atmospheric humidity profile at varying oxygen levels with

a laser based monitoring system

D Das¹, G A Ahmed², G K D Mazumder³ and A Choudhury⁴

¹Department of Physics, North Gauhati College, 781031, Assam, India

²Department of Physics, Tezpur University 784028, Assam, India.

³USIC, Gauhati University, 781014, Assam, India.

⁴Department of Physics, Tezpur University, 784028, Assam, India

gazi@tezu.ernet.in; gaziaahmed@yahoo.com

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A laser based Air Quality Monitoring system was designed and fabricated in an attempt to synthesize design principles of a nephelometer and a transmissiometer and monitor specific constituents of the atmosphere. Essentially in the system light from a He-Ne laser source passes through a simulation chamber and the extinction and scattering is monitored by a set of phototransistor based detectors. The signals from the detectors are digitized and interfaced to a personal computer, where a data acquisition software "moniotors" and records the data which is subsequently analyzed using spreadsheet programs. This paper reports the design aspects of the fabricated instrument and gives the findings of investigations done on atmospheric humidity at varying oxygen levels. ©Anita Publications. All rights reserved.

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References

1. Ahmed G A, Mazumder G K D, Choudhary A, J Instrument Sot India, 26 (1996) 734.

2. Pritchard B S. Elliott W G, J Opt Soc Am, 50 (1960) 191.

3. Jonasz M. Appl Opt, 29, (1990) 64.

4. Hinkley E D, Laser monitoring of the atmosphere, (Springer - Verlag, Berlin), 1976, p 62.

[Received : 12.3.2001]

ASIAN JOURNAL OF PHYSICS