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811.
Surface vertical displacements, potential perturbations andgravity changes of a viscoelastic earth model induced by internal point dislocations 总被引:1,自引:0,他引:1
Hansheng Wang 《Geophysical Journal International》1999,137(2):429-440
Using the viscoelastic correspondence principle, we utilize the surface coseismic spheroidal deformation fields (i.e. vertical displacements, potential perturbations and gravity changes) of SNREI earth models caused by four typical types of point dislocation, derived by Sun & Okubo (1993 ), to deduce the fundamental formulas for spheroidal fields relevant to viscoelastic earth models. In computations, we employ a strike-slip dislocation on a vertical plane buried at the bottom of the lithosphere to estimate the maximal viscous relaxation responses to this kind of source that possibly exist on the surface of the earth. We take the seismic moment as 1022 N m, which is characteristic of an average large earthquake. The numerical results demonstrate that, if we take the viscosity as 1019 Pa s in the asthenosphere, and 1021 Pa s in the other mantle layers, the rates of surface vertical displacements and gravity changes within about 2.5° for the 10 postseismic years are respectively 1.5–8.1 cm yr−1 and 4.0–14.9 μgal yr−1 : the viscous relaxation for this mantle viscosity profile proceeds much faster than for a constant mantle viscosity of 1021 Pa s. 相似文献
812.
东胜煤田矿区绿化初见成效 总被引:4,自引:0,他引:4
本文介绍了矿区荒漠化土地对东胜煤田开发的危害, 东胜露天矿开发对该区荒漠化土地的影响, 以及为了保证东胜煤田顺利开发, 对矿区荒漠化土地的综合治理现状。 相似文献
813.
艾肯达坂风雪流形成机制及其治理 总被引:6,自引:1,他引:5
根据天山艾肯达坂地区的野外观测和风洞模拟实验,导出山区风雪流输送量与风速随高度分布方程,指出贴地气层分离是形成道路雪阻的主要原因。首次提出利用透风式下导风清除道路积雪的理论与方法,在风雪流灾害防治工程的实施中取得了巨大的经济和社会效益。 相似文献
814.
Correlation-coefficient fields are widely used in short-term climate prediction research. The most frequently used significance test method for the correlation-coefficient field was proposed by Livezey, in which the number of significantcorrelation lattice(station) points on the correlation coherence map is used as the statistic. However, the method is based on two assumptions:(1) the spatial distribution of the lattice(station) points is uniform;and(2) there is no correlation between the physical quantities in the correlation-coefficient field. However, in reality, the above two assumptions are not valid.Therefore, we designed a more reasonable method for significance testing of the correlation-coefficient field. Specifically, a new statistic, the significant-correlation area, is introduced to eliminate the inhomogeneity of the grid(station)-point distribution, and an empirical Monte Carlo method is employed to eliminate the spatial correlation of the matrix.Subsequently, the new significance test was used for simultaneous correlation-coefficient fields between intensities of the atmospheric activity center in the Northern Hemisphere and temperature/precipitation in China. The results show that the new method is more reasonable than the Livezey method. 相似文献
815.
We have observed about 15 active regions on the Sun, with the Advanced Stokes Polarimeter and Dick Dunn Telescope at NSO/SP to map the Stokes parameters in the photospheric Fe 6302.5 Å and chromospheric Mg I 5173 Å lines, during 1999‐2002. The observations are corrected for dark current, gain, instrumental polarization and cross‐talk using ASP pipeline. The wavelength calibration is carried out using the O2 telluric line 6302 Å which is also present in the observations. The photospheric and chromospheric longitudinal magnetograms are made from the Stokes V profiles, which were intercalibrated with the Kitt Peak magnetograms. The plasma motions are inferred from the line bisector measurements at different positions of the spectral line. In this paper we present the height dependence of Doppler velocity scatter plots of a sunspot in the photospheric Fe I 6302 Å line. 相似文献
816.
817.
818.
北京地区重磁数据计算机图像处理及地质效果 总被引:2,自引:1,他引:1
介绍了对北京地区重力和磁力数据进行计算机图像处理的技术及流程,解译了重磁数据图像处理结果,分析了重磁数据计算机图像处理的地质效果,得到了一些对北京地区成矿预测有益的新认识 相似文献
819.
Bacterial interaction with oil and sea water, in a porous medium, was studied using a transparent micro model mounted on
a cybernetic-controlled positioning board of an inverted microscope. This was interfaced with computer-operated image analysis
and surveillance equipment. Consecutive flooding of the model allowed oil to become trapped by capillary forces. Hydrocarbonoclastic
bacteria were inoculated. The interaction of biofilm and oil was monitored during a period of 25 days, while mineral salts
were supplied intermittently. A unique feature of biofilm behaviour was discovered. The phenomenon is discussed, and calculations
are presented. A possible explanation of the phenomenon appears to be local reductions of the surface tension. The phenomenon
helps explain why bacteria are able to mobilise oil trapped by capillary forces without reducing the interfacial tension to
a level that leads to an increase in the capillary number sufficient to explain incremental oil recovery. The experimental
design is believed to be suitable for studying biofilm behaviour on the pore level.
Received: 26 January 1998 · Accepted: 9 July 1998 相似文献
820.
M. Kissler‐Patig Y. Copin P. Ferruit A. Pcontal‐Rousset M.M. Roth 《Astronomische Nachrichten》2004,325(2):159-162
As integral field spectrographs have become more common around the world and in Europe in particular, the need for a common data format has been recognized. Here, we present the Euro3D format that is adapted as a post‐instrumentalsignature‐removal format for all instruments within the Euro3D network. It follows the FITS standard, and includes several extensions, all of them being binary FITS tables. This article is intended to give a comprehensive overview, but does not attempt to serve as a full definition document. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献