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31.
严格论证了在对空间或地面目标的定位中,利用伪距测量观测模型的几何因子大于用台站间一次差分观测模型的几何因子.此外,台站间完全差分测量观测的定位精度优于不完全测量情形的定位精度.这些结果给人们在实际工作中采取何种定位方式提供了可靠的理论依据. 相似文献
32.
33.
This paper presents a numerical model for predicting the dynamic response of rock mass subjected to large‐scale underground explosion. The model is calibrated against data obtained from large‐scale field tests. The Hugoniot equation of state for rock mass is adopted to calculate the pressure as a function of mass density. A piecewise linear Drucker–Prager strength criterion including the strain rate effect is employed to model the rock mass behaviour subjected to blast loading. A double scalar damage model accounting for both the compression and tension damage is introduced to simulate the damage zone around the charge chamber caused by blast loading. The model is incorporated into Autodyn3D through its user subroutines. The numerical model is then used to predict the dynamic response of rock mass, in terms of the peak particle velocity (PPV) and peak particle acceleration (PPA) attenuation laws, the damage zone, the particle velocity time histories and their frequency contents for large‐scale underground explosion tests. The computed results are found in good agreement with the field measured data; hence, the proposed model is proven to be adequate for simulating the dynamic response of rock mass subjected to large‐scale underground explosion. Extended numerical analyses indicate that, apart from the charge loading density, the stress wave intensity is also affected, but to a lesser extent, by the charge weight and the charge chamber geometry for large‐scale underground explosions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
34.
THECONSTRUCTIONANDITSDEVELOPMENTOFTHEOVERSEASTRANSPORTSYSTEMINNORTHEASTCHINAGaoShali(高莎丽)(DepartmentofGeography,NortheastNorm... 相似文献
35.
郭红锋 《紫金山天文台台刊》2003,(1)
本文简单介绍了光干涉与综合孔径技术发展的历史、国际上用于天文观测的一些著名光干涉仪的技术特点和进展、以及近年来我国开展的与光干涉 ,综合孔径技术有关的工作 ,最后简要介绍了在光学综合孔径技术领域所发展的光纤与集成光学等新技术 相似文献
36.
EFFECT OF SULPHATE-REDUCING BACTERIA ON ELECTRO-CHEMICAL CORROSION BEHAVIOR OF 16Mn STEEL IN SEA MUD
INTRODUCTIONItwasgenerallyconsideredpreviouslythatthecorrosionofsteelinseamudwasnotserious.However,itwaslaterfoundthatthecorrosionrateofsteelinsomeseamudwashigherthanthatinseawater(King,1980;Sehmide,1982;Guoetal.,1997;Hou,1998).Therearesomereportsthatthecorrosionr… 相似文献
37.
INTRODUCTIONTheSubeiShoalandtheChangjiangRiverestuarineareainthewestoftheHuanghaiandEastChinaSeasisoneofthemarginalseasintheworld ,wheresuspendedmatterisextremelyhigh .Here ,notonlyistheretheTaiwanWarmCurrentoneoftheKuroshio’sbranchesintheEastChinaSea,butalsotheHuanghaiCoastalCurrent,andChangjiangDilutedWater.Sothestrongmixingbetweenthecoastalandoffshorewaterscomplicatessuspendedmatterdistributioninthisarea.HowthesuspendedmatterdischargedfromtheChangjiangRiverandtheabandonedHuan… 相似文献
38.
Biogenic silicate accumulation in sediments, Jiaozhou Bay 总被引:1,自引:0,他引:1
1 INTRODUCTION Silicate, or silicic acid (H4SiO4), is a very im- portant nutrient in the ocean. Unlike other major nu- trients such as phosphate and nitrate or ammonium, which are needed by almost all marine plankton, silicate is an essential chemical req… 相似文献
39.
For a Hamiltonian that can be separated into N+1(N\geq 2) integrable parts, four algorithms can be built for a symplectic integrator. This research compares these algorithms for the
first and second order integrators. We found that they have similar local truncation errors represented by error Hamiltonian
but rather different numerical stability. When the computation of the main part of the Hamiltonian, H
0, is not expensive, we recommend to use S
* type algorithm, which cuts the calculation of the H
0 system into several small time steps as Malhotra(1991) did. As to the order of the N+1 parts in one step calculation, we found that from the large to small would get a slower error accumulation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
40.
山东省产业重心转移与可持续发展研究 总被引:22,自引:0,他引:22
孙希华 《地球信息科学学报》2001,3(1):27-31
本文利用经济空间结构的重心研究方法,分析了山东省近八年来产业重心的转移,提出了山东省产业可持续发展战略 相似文献