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71.
We discuss the range of validity of solutions of the Schrödinger equation with a temperaturemodified Coulomb potential. Such a potential, as was recently pointed out, may be relevant to the resolution of the long-standing problem of unidentified solar emission lines. We also consider in detail a predictive test of our approach, and draw attention to some related conceptual issues. 相似文献
72.
We have investigated some properties such as speed, apparent width, acceleration, latitude, mass and kinetic energy, etc. of all types of coronal mass ejections (CMEs) observed during the period 1996–2007 by SOHO/LASCO covering the solar cycle 23. The results are in satisfactory agreement with previous investigations. 相似文献
73.
Severe cases of damages of mountain tunnels following 1995 Hyogoken-Nanbu (Japan), 1999 Chi-Chi (Taiwan), 2004 Mid-Niigata Prefecture (Japan) and 2008 Wenchuan (China) earthquakes have challenged the traditional belief of tunnel structures being seldom damaged in seismic events. These experiences are a reminder that seismic behaviour of mountain tunnels must be further studied in detail. Such investigations assume greater significance as more number of tunnels are being planned to be constructed to meet the infrastructural needs of mountainous regions all around the world. In this paper, seismic damages of mountain tunnels have been reviewed. Prominent failure patterns have been identified based on the case histories of damages. Damages in the form of cracking of tunnel lining, portal cracking, landslide induced failures, uplift of bottom pavement, failures of sidewalls, shearing failure of tunnel liner and spalling of concrete have been majorly observed. Based on the damage patterns and earthquake data, main factors leading to instabilities have been discussed. Probable failure mechanisms of mountain tunnels under seismic loading conditions have been explained. Seismic analyses of a circular lined tunnel in blocky rock mass have been carried out through discrete element based approach. The significant role of different seismic parameters like frequency, peak ground acceleration has been identified. Moreover, effect of tunnel depth on the seismic response of tunnels has been investigated. It is believed that the present study will help in advancing the present state of understanding with regard to the behavior of tunnels under seismic conditions. 相似文献
74.
Natural Hazards - New mapping through geomorphic analysis of tectonic landforms using a variety of freely available satellite data, including shuttle radar topography and Google Maps, has revealed... 相似文献
75.
76.
Ananth Krishna N. S. Gopinath N. S. Hegde N. K. Malik 《Journal of Earth System Science》2005,114(6):739-748
The Chandrayaan-1 mission proposes to put a 550 kg lunarcraft into Geostationary Transfer Orbit (GTO) using the Polar Satellite
Launch Vehicle (PSLV) which will subsequently be transferred into a 100 km circular lunar polar orbit for imaging purposes.
In this paper, we describe certain aspects of mission strategies which will allow optimum power generation and imaging of
the lunar surface.
The lunar orbit considered is circular and polar and therefore nearly perpendicular to the ecliptic plane. Unlike an Earth
orbiting remote sensing satellite, the orbit plane of lunar orbiter is inertially fixed as a consequence of the very small
oblateness of the Moon. The Earth rotates around the Sun once a year, resulting in an apparent motion of Sun around this orbit
in a year. Two extreme situations can be identified concerning the solar illumination of the lunar orbit, noon/midnight orbit,
where the Sun vector is parallel to the spacecraft orbit plane and dawn/dusk orbit, where the Sun vector is perpendicular
to the spacecraft orbit plane. This scenario directly affects the solar panel configuration. In case the solar panels are
not canted, during the noon/midnight orbit, 100% power is generated, whereas during the dawn/dusk orbit, zero power is generated.
Hence for optimum power generation, canting of the panels is essential. Detailed analysis was carried out to fix optimum canting
and also determine a strategy to maintain optimum power generation throughout the year. The analysis led to the strategy of
180‡ yaw rotation at noon/midnight orbits and flipping the solar panel by 180‡ at dawn/dusk orbits. This also resulted in
the negative pitch face of the lunarcraft to be an anti-sun panel, which is very useful for thermal design, and further to
meet cooling requirements of the spectrometers.
In principle the Moon’s surface can be imaged in 28 days, because the orbit chosen and the payload swath provide adequate
overlap. However, in reality it is not possible to complete the imaging in 28 days due to various mission constraints like
maximum duration of imaging allowed keeping in view the SSR sizing and payloads data input rate, time required for downlinking
the payload data, data compression requirements and visibility of the lunarcraft for the Bangalore DSN. In each cycle, all
the latitudes are swept. Due to the constraints mentioned, only 60‡ latitude arc coverage is possible in each orbit. As Bangalore
DSN is the only station, half of the orbits in a day are not available. The longitudinal gaps because of non-visibility are
covered in the next cycle by Bangalore DSN. Hence, in the firstprime imaging season, only 25% of the prime imaging zones are covered, and an additional threeprime imaging seasons are required for a full coverage of the Moon in two years. Strategy is also planned to cover X-ray payload coverage considering
swath and orbit shift. 相似文献
77.
Stewart W.I. Chu D. Malik S. Lerner S. Singh H. 《Oceanic Engineering, IEEE Journal of》1994,19(4):599-610
Bathymetry and backscatter measurements from a 120-kHz phase-difference sonar are analysed in terms of statistical and spectral characteristics. Data from a multisensor, multiscale survey of the Juan de Fuca Ridge are compared across three distinct geological provinces: sediment pond, ridge flank, and axial valley. The detrended bathymetry follows a Gaussian distribution; the power spectral density can be approximately described by a power law. The composite multiscale power spectrum demonstrates a similar slope spanning a spatial frequency range from about 0.005 to 50 cycles/m, corresponding to a range of geological features from a few hundred meters down to several centimeters. The backscattering strength and grazing-angle dependencies agree with previous empirical studies; data from a sediment-pond region are shown to match theoretical predictions of the composite-roughness model. Histograms of the echo amplitude are characterized by a multimodal Rayleigh probability density function. For all analyses, the data show distinct differences among the three provinces 相似文献
78.
Relativistic flows both in stellar interior and stellar atmospheres are obviously in action, hence, their treatment is of interest. The present communication aims at deriving by a different method the general equations that govern such flows.The derivation is based merely on the first two principles of thermodynamics and the inertia-energy equivalence principles; while the end results are the formulation of the energy tensor and the energy-flux and momentum equations. The assumptions of ideal flow and adiabatic behaviour of the medium adopted here are restrictive. 相似文献
79.
The causes of the failure of various dams, the existing approaches to determining the parameters of flood waves caused by dam failures, and the authors' method of calculation of these waves are considered. Characterization of the consequences of the dam-failure flood wave in the tailwater pool of the Volgograd hydroelectric station and some unfavorable aspects of possible evacuation of the Saratov reservoir are presented. 相似文献
80.
Michio Morino Javed N. Malik Prashant Mishra Chandrashekhar Bhuiyan Fumio Kaneko 《Journal of Earth System Science》2008,117(3):181-188
Several new active fault traces were identified along Katrol Hill Fault (KHF). A new fault (named as Bhuj Fault, BF) that
extends into the Bhuj Plain was also identified. These fault traces were identified based on satellite photo interpretation
and field survey. Trenches were excavated to identify the paleoseismic events, pattern of faulting and the nature of deformation.
New active fault traces were recognized about 1km north of the topographic boundary between the Katrol Hill and the plain
area. The fault exposure along the left bank of Khari River with 10m wide shear zone in the Mesozoic rocks and showing displacement
of the overlying Quaternary deposits is indicative of continued tectonic activity along the ancient fault. The E-W trending
active fault traces along the KHF in the western part changes to NE-SW or ENE-WSW near Wandhay village.
Trenching survey across a low scarp near Wandhay village reveals three major fault strands F1, F2, and F3. These fault strands
displaced the older terrace deposits comprising Sand, Silt and Gravel units along with overlying younger deposits from units
1 to 5 made of gravel, sand and silt. Stratigraphic relationship indicates at least three large magnitude earthquakes along
KHF during Late Holocene or recent historic past. 相似文献