A Report on the National Symposium on Remote Sensing of Environment with Special Emphasis on Green Revolution and Annual Convention of Indian Society of Remote Sensing held at Ludhiana during November 22–24,1995     

P. K. Sharma 《Journal of the Indian Society of Remote Sensing》1995,23(4):vi-ix

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Alfvénic drift Kelvin-Helmholtz instability in the presence of an equilibrium electric field     

Avadhesh C. Sharma  Krishna M. Srivastava 《Astrophysics and Space Science》1992,197(1):145-151

Alfvénic drift Kelvin-Helmholtz instability is discussed in the presence of equilibrium electric and magnetic fields which are perpendicular to each other. A dispersion relation is achieved with the help of WKB approximation and the instability criterion is established. A comparison is made with the previous studies and it is shown that the electric field has a stabilizing or destabilizing effect on the system according to the conditions discussed in the text.  相似文献   

The periodic orbits of the second kind in terms of Giacaglia's variables with oblateness     

Ram Krishan Sharma 《Earth, Moon, and Planets》1989,45(3):213-218

Utilizing secular perturbing potential due to oblateness, the existence of periodic orbits of the second kind is established through analytic continuation using Giacaglia's canonical variables in the planar restricted three-body problem when the more massive primary is an oblate spheroid with its equatorial plane coincident with the plane of motion.  相似文献   

Latitudinal variation of cosmic noise absorption     

S.B.S.S. SarmaM.C. Sharma 《Planetary and Space Science》1971

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Polarisations of quasi-waves in a general anisotropic porous solid saturated with viscous fluid     

M. D. Sharma 《Journal of Earth System Science》2005,114(4):411-419

Wave propagation is studied in a general anisotropic poroelastic solid saturated with a viscous fluid flowing through its pores of anisotropic permeability. The extended version of Biot’s theory is used to derive a system of modified Christoffel equations for the propagation of plane harmonic waves in such media. The non-trivial solution of this system is ensured by a biquadratic equation whose roots represent the complex velocities of four attenuating quasi-waves in the medium. These complex velocities define phase velocity and attenuation of each quasi-wave propagating along a given phase direction in three-dimensional space. The solution itself defines the polarisations of the quasi-waves along with phase shift. The variations of polarisations of quasi-waves with their phase direction, are computed for a realistic numerical model.  相似文献   

High energy X-γ ray spectrometer on the Chandrayaan-1 mission to the Moon     

J. N. Goswami  D. Banerjee  N. Bhandari  M. Shanmugam  Y. B. Acharya  D. V. Subhedar  M. R. Sharma  C. N. Umapathy  P. Sreekumar  M. Sudhakar  L. Abraham  P. C. Agrawal 《Journal of Earth System Science》2005,114(6):733-738

The Chandrayaan-1 mission to the Moon scheduled for launch in late 2007 will include a high energy X-ray spectrometer (HEX) for detection of naturally occurring emissions from the lunar surface due to radioactive decay of the²³⁸U and²³²Th series nuclides in the energy region 20–250 keV. The primary science objective is to study the transport of volatiles on the lunar surface by detection of the 46.5 keV line from radioactive²¹⁰Pb, a decay product of the gaseous²²²Rn, both of which are members of the²³⁸U decay series. Mapping of U and Th concentration over the lunar surface, particularly in the polar and U-Th rich regions will also be attempted through detection of prominent lines from the U and Th decay series in the above energy range. The low signal strengths of these emissions require a detector with high sensitivity and good energy resolution. Pixelated Cadmium-Zinc-Telluride (CZT) array detectors having these characteristics will be used in this experiment. Here we describe the science considerations that led to this experiment, anticipated flux and background (lunar continuum), the choice of detectors, the proposed payload configuration and plans for its realization  相似文献   

Morphometric analysis of sub-watersheds in Gurdaspur district, Punjab using remote sensing and GIS techniques   总被引：4，自引：0，他引：4  

Rajiv Chopra  Raman Deep Dhiman  P. K. Sharma 《Journal of the Indian Society of Remote Sensing》2005,33(4):531-539

Morphometric analysis of two sub-watersheds was carried using remote sensing and GIS techniques. Detailed drainage map prepared from aerial photographs and SOI toposheets was updated using latest IRS-ID PAN sharpened LISS-III analog data. Updated drainage maps were used for the morphometric analysis of the two sub-watersheds. Both the sub-watersheds show dendritic to sub-dendritic drainage pattern with moderate drainage texture. High bifurcation ratio indicates a strong structural control on the drainage. Logarithm of number of stream vs. stream order show deviation from straight line indicating regional upliftment. In spite of mountainous relief, low drainage density values indicate that the area is underlain by impermeable sub-surface material. Circulatory and elongation ratios show that both the sub-watersheds have elongated shape.  相似文献   

Village level crop inventory using remote sensing and field survey data     

R. P. Singh  V. N. Sridhar  V. K. Dadhwal  R. Jaishankar  M. Neelkanthan  A. K. Srivastava  G. D. Bairagi  N. K. Sharma  S. A. Raza  Rajesh Sharma  Manoj Yadav  F. K. Joshi  N. L. Purohit 《Journal of the Indian Society of Remote Sensing》2005,33(1):93-98

This paper presents results of a pilot study in six villages located in the states of Haryana, Rajasthan and Madhya Pradesh, to evaluate accuracy of crop area at village level estimated by IRS - LISS-I1I data with respect to detailed field survey carried out by National Sample Survey Organization. The selected villages were located in Karnal, Kota and Bhopal districts which represented single dominant wheat crop as well as wheat-mustard and wheat-gram situation, respectively. Accuracy assessment of remote sensing based estimate with field survey of NSSO showed relative deviation in wheat estimate ranging from 3.72 percent for Mainmati village in Karnal district in Haryana to 22.65 percent fo Ranpur village in Kota district of Rajasthan. It was found that relative deviation in area estimation is inversely poportional to the crop proportion in that village. Observations of over estimation at low crop proportion and underestimation at higher crop proportion was explained by simple budgeting of relative proportion of ommision and commision errors. The study demonstrates that on the average, 90 percent crop area accuracy is possible with LISS-II1 data and the adopted approach.  相似文献   

Effect of initial stress on reflection at the free surface of anisotropic elastic medium     

M. D. Sharma 《Journal of Earth System Science》2007,116(6):537-551

The propagation of plane waves is considered in a general anisotropic elastic medium in the presence of initial stress. The Christoffel equations are solved into a polynomial of degree six. The roots of this polynomial represent the vertical slowness values for the six quasi-waves resulting from the presence of a discontinuity in the medium. Three of these six values are identified with the three quasi-waves traveling in the medium but away from its boundary. Reflection at the free plane surface is studied for partition of energy among the three reflected waves. For post-critical incidence, the reflected waves are inhomogeneous (evanescent) waves. Numerical examples are considered to exhibit the effects of initial stress on the phase direction, attenuation and reflection coefficients of the reflected waves. The phase velocities and energy shares of the reflected waves change significantly with initial stress as well as anisotropic symmetry. The presence of initial stress, however, has a negligible effect on the phase directions of reflected waves.  相似文献   

Existence and Stability of Libration Points in the Restricted Three-Body Problem When the Primaries are Triaxial Rigid Bodies     

Ravinder Kumar Sharma  Z. A. Taqvi  K. B. Bhatnagar 《Celestial Mechanics and Dynamical Astronomy》2001,79(2):119-133

This paper deals with the stationary solutions of the planar restricted three-body problem when the primaries are triaxial rigid bodies with one of the axes as the axis of symmetry and its equatorial plane coinciding with the plane of motion. It is seen that there are five libration points, two triangular and three collinear. It is further observed that the collinear points are unstable, while the triangular points are stable for the mass parameter 0 < _crit(the critical mass parameter). It is further seen that the triangular points have long or short periodic elliptical orbits in the same range of .This revised version was published online in October 2005 with corrections to the Cover Date.  相似文献