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111.
The far-reaching gravitational force—in the approximation of Newton’s law of gravitation—is described by a heuristic model with hypothetical massless particles propagating at the speed of light in vacuum and transferring momentum and energy between physical entities through interactions on a local basis. The model has some similarities with the impact theory presented by Nicolas Fatio de Duillier to the Royal Society in 1690. Objections raised against this idea are dispelled by invoking the Special Theory of Relativity, considering non-local interactions, and replacing the shielding concept by a secular mass increase of massive bodies. Some consequences and applications of the model are discussed. 相似文献
112.
Steady state level density of 20 levels of boron-like ions, Mg viii and Si x, have been computed as a function of electron density and temperature. We have accounted for collisional and spontaneous radiative processes. Photo-excitation between the two levels of the ground term has also been considered. Using the computed level density, line intensities have been obtained as a function of electron density and temperature. In case of Mg viii, line intensity ratio I(430.47)/I(436.62) is found to be electron density sensitive. Likewise other pairs of lines namely, I(75.03)/I(74.86), I(315.02)/I(430.47), and I(315.02)/I(335.23) are also found to be density sensitive. Similar density sensitive line intensity ratios have been found for Si x. Absolute line fluxes from these ions at earth distance have been computed and are found to be comparable with values obtained, using various satellite and rocket measurements.Paper presented at the 5th Astronomical Society of India Meeting, held at Uttar Pradesh State Observatory, Naini Tal, India, 5–9 November, 1979. 相似文献
113.
B. N. Dwivedi 《Astrophysics and Space Science》1990,172(1):47-50
Emission line intensities from MgVI, SiVIII, andSX ions of nitrogen sequence have been computed by use of the model atmosphere of Kopp and Orrall (1976) for the quiet Sun and coronal holes and compared with observational data available from rocket and satellite. 相似文献
114.
Electron density in a coronal hole is rediscussed using the new calculation for the Mgviii 436.62/430.47 density-sensitive theoretical line ratio and with the help of available observations. 相似文献
115.
R. S. Dwivedi K. Sreenivas K. V. Ramana P. R. Reddy G. Ravi Sankar 《Journal of the Indian Society of Remote Sensing》2006,34(4):351-367
Realizing the potential of spaceborne multispectral measurements in providing spatial information on natural resources, and
of Geographic Information System (GIS) in integrating such information with the socio-economic data and other collateral information
to arrive at derivative information, we report here the results of a study which was taken up in a watershed in Charkhari
block of Mahoba district, northern India, to generate the information on natural resources from Indian Remote Sensing Satellite
(IRS-1B) Linear Imaging Self-scanning Sensor (LISS-II) images through a systematic visual interpretation, and its subsequent
integration with the collateral information in a GIS environment to develop optimal land use plan/action plan for sustainable
development of its land resources. Since permanent vegetation cover in the watershed has been dwindling due to population
pressure, the need for establishing more vegetation cover has been stressed. 相似文献
116.
The effects of acidic medium on the fry of Cyprinus carpio have been studied. The eggs of Cyprinus carpio were obtained from the Bilawali Fish Farm, Indore M.P. in July 1976. The eggs were put in various concentrations of HCl ranging from 0.0025 ppm to 0.0500 ppm. One specimen from each experimental group was sacrificed for histological studies every week. The microtomy sections were studied under high power. It was found that when the fries were kept in acidic medium following changes took place:
- - Nucleus became inconspicuous and cell wall became disorganised;
- - muscle layers of gut wall became indistinct and disorganised to some extent;
- - epithelial lining of the gut was partially destroyed.
- - vacuolation in the connective tissue of gut was seen due to destruction of some of the cells;
- - hepatic cells of the liver were destroyed at various spots to a varying degree.
117.
R. S. Dwivedi 《Journal of the Indian Society of Remote Sensing》1985,13(2):61-64
This paper presents a case study of the utility of Landsat MSS imagery for soil resoruces mapping in Silent Valley and its environs covering about 33,000 sq. km. area. A collective approach involving monoscopic visual interpretation of Landsat imagery in conjunction with the lithological and topographical information supported by limited field check has been followed to prepare a soil map on 1:250,000 scale showing sub-groups/association of sub-groups. Future prospect of using spaceborne data for soil mapping has also been discussed. 相似文献
118.
Natural Hazards - The present paper assesses the slope stability of the Tungnath Temple at Rudraprayag District, in the Indian state of Uttarakhand, and suggests the remedial measures. The... 相似文献
119.
The Red Sea continental margin (RSCM) corresponds to a wide hinge zone between Red Sea and Arabian plate. This margin has been studied through geological and geophysical observations primarily in regard to the evolution of Red Sea rift. This margin is characterized by occurrence of thin sediments, significant onshore uplift, tectonic subsidence of the offshore sedimentary basin, active faulting and seismicity. Studies indicate that sedimentary sequences of the margin are deformed by faults and folds resulti... 相似文献
120.
We have studied cosmological model generated by perfect fluid coupled with mass less scalar field for Kantowski–Sachs space–time in general theory of relativity. Two different physically viable models of the universe are obtained by using a special law of variation for Hubble’s parameter that yields a constant value of deceleration parameter. Some physical consequences of the models have been discussed in case of Zel’dovich fluid. 相似文献