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1.
2.
The most general accurate solutions for the Buchdhal fluid sphere were obtained and matched with the Schwarzchild's exterior
solution at the pressure free interface. Various parameters of the solutions were so adjusted that the energy density, pressure
and temperature were positive and decreasing away from the centre, and the velocity of sound was less than unity throughout
the spheroid model. Using this procedure, the maximum mass of the fluid sphere with a surface density of2 × 1014gm cm-3 was determined to be 3.82MΘ and 4.57 MΘ for strong and weak energy conditions respectively. PACS number: 0402, 0402J, 0440D,
95301
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
The new calculations of the Oiv temperature-sensitive EUV line ratios are presented and compared with previous results. 相似文献
4.
5.
A critical analysis of CH, NH, OH, C2, and CN molecules/radicals has been made in twenty-four F- and early G-type dwarfs at different effective temperature as well as in new constructed model atmosphere. Molecular indices of bandheads ofA-X system of CH, NH, OH, C2, and CN have been obtained by using the data available in the literature (thirteen-colour and eight-colour photometry).Besides, some interesting plots of the molecular indices vs eff, molecular abundances and molecular indices vs dissociation energy, reduced equivalent widths and FCF's vs dissociation energy for respective molecules have also been enumerated. It is found that the molecular indices at bandheads ofA-X system of CH, NH, OH, C2, and CN are approximately constant (5810–6570 K). It is to be noted that the molecular indices decrease in the order OH, NH, CH, C2, and CN at a given temperature.The dissociation equilibrium of CH, NH, OH, C2, and CN is considered at 5810, 6570, and 7160 K phases in model atmosphere. At standard scale of abundance the molecular abundance and molecular index decrease in the order OH, NH, CH, C2, and CN at any given phase, however, CN abundance and index increase (eff=0.867-0.767). The amplitude of abundance and index variation decrease in the order NH, OH, CH, C2, and CN (eff=0.767-0.704).The reduced equivalent width decrease in the order OH, NH, CH, and C2 and FCF's decrease in the order CH, OH, NH, CN, and C2.The confrontation of models and observations of spectra of F- and early G-type dwarfs of parent molecules is of primary importance to investigate the physical conditions within atmospheres. Reliable excitation models are also requisite for interpreting spectroscopic observations of parent molecules and deriving molecular abundances. 相似文献
6.
The flow of laser radiation in a plane-parallel cylindrical slab of active amplifying medium with axial symmetry is treated as a problem in radiative transfer. The appropriate one-dimensional transfer equation describing the transfer of laser radiation has been derived by an appeal to Einstein'sA, B coefficients (describing the processes of stimulated line absorption, spontaneous line emission, and stimulated line emission sustained by population inversion in the medium) and considering the rate equations to completely establish the rational of the transfer equation obtained. The equation is then exactly solved and the angular distribution of the emergent laser beam intensity is obtained; its numerically computed values are given in tables and plotted in graphs showing the nature of peaks of the emerging laser beam intensity about the axis of the laser cylinder. 相似文献
7.
Magnetotelluric investigations have been carried out in the Garhwal Himalayan corridor to delineate the electrical structure
of the crust along a profile extending from Indo-Gangetic Plain to Higher Himalayan region in Uttarakhand, India. The profile
passing through major Himalayan thrusts: Himalayan Frontal Thrust (HFF), Main Boundary Thrust (MBT) and Main Central Thrust
(MCT), is nearly perpendicular to the regional geological strike. Data processing and impedance analysis indicate that out
of 44 stations MT data recorded, only 27 stations data show in general, the validity of 2D assumption. The average geoelectric
strike, N70°W, was estimated for the profile using tensor decomposition. 2D smooth geoelectrical model has been presented,
which provides the electrical image of the shallow and deeper crustal structure. The major features of the model are (i) a low resistivity (<50Ωm), shallow feature interpreted as sediments of Siwalik and Indo-Gangetic Plain, (ii) highly resistive (> 1000Ωm) zone below the sediments at a depth of 6 km, interpreted as the top surface of the Indian plate,
(iii) a low resistivity (< 10Ωm) below the depth of 6 km near MCT zone coincides with the intense micro-seismic activity in the
region. The zone is interpreted as the partial melting or fluid phase at mid crustal depth. Sensitivity test indicates that
the major features of the geoelectrical model are relevant and desired by the MT data. 相似文献
8.
Prakash C. Sinha Indu Jain Neetu Bhardwaj Ambarukhana D. Rao Shishir K. Dube 《Natural Hazards》2008,45(3):413-427
The Orissa coast of India is one of the most vulnerable regions of extreme sea levels associated with severe tropical cyclones.
There was extensive loss of life and property due to the October 1999 super cyclone, which devastated large part of the Orissa
coast. The shallow nature of the head bay, presence of a large number of deltas formed by major rivers of Orissa such as Mahanadi
and Dhamra, and high tidal range are responsible for storm surge flooding in the region. Specifically, rising and falling
tidal phases influence the height, duration, and arrival time of peak surge along the coast. The objective of the present
study is to evaluate the tide-surge interaction during the 1999 Orissa cyclone by using nonlinear vertically integrated numerical
models. The pure tidal solution for the head bay region of the Bay of Bengal provides the initial condition for the fine resolution
nested grid Orissa model. However, the feedback from the Orissa model does not affect the head bay model as the study provides
a one-way interaction. Numerical experiments are performed to study the tide-surge interaction by considering various relative
phases of the tidal waves with the surge-wave produced by 1999 Orissa cyclone. The comparison, although utilizing only the
limited estimates of tidal data, appears adequate to assert that the principal features are reproduced correctly. 相似文献
9.
10.
The radioelement and heavy mineral distribution in river, beach and innershelf areas of the southern Kerala coast is related
to placer mineral concentration on the beaches at Chavara. Southern Kerala rivers—Neyyar, Karamana and Vamanapuram—transport
higher amounts of radioactive elements than the larger Kallada River due to higher radioactive minerals in the hinterland
rocks. Coastal configurations and the seasonal longshore current pattern seems to control along-shore distribution of minerals.
The proposed model for placer concentration suggests that the energy difference and seasonal current direction along this
coast is important. 相似文献