92 resultados para 165-999B
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
The Load Unload Response Ratio (LURR) method is an intermediate-term earthquake prediction approach that has shown considerable promise. It is inspiring that its predictions using LURR have been improving. Since 2004 we have made a major breakthrough in intermediate-term earthquake forecasting of the strong earthquakes on the Chinese mainland using LURR and successfully predicted the Pakistan earthquake with magnitude M 7.6 on October 8, 2005. The causes for improving the prediction in terms of LURR have been discussed in the present paper.
Resumo:
There are seven strong earthquakes with M >= 6.5 that occurred in southern California during the period from 1980 to 2005. In this paper, these earthquakes were studied by the LURR (Load/Unload Response Ratio) method and the State Vector method to detect if there are anomalies before them. The results show that LURR anomalies appeared before 6 earthquakes out of 7 and State Vector anomalies appeared before all 7 earthquakes. For the LURR method, the interval between maximum LURR value and the forthcoming earthquake is 1 to 19 months, and the dominant mean interval is about 10.7 months. For the State Vector method, the interval between the maximum modulus of increment State Vector and the forthcoming earthquake is from 3 to 27 months, but the dominant mean interval between the occurrence time of the maximum State Vector anomaly and the forthcoming earthquake is about 4.7 months. The results also show that the minimum valid space window scale for the LURR and the State Vector is a circle with a radius of 100 km and a square of 3 degrees 3 degrees, respectively. These results imply that the State Vector method is more effective for short-term earthquake prediction than the LURR method, however the LURR method is more effective for location prediction than the State Vector method.
Resumo:
The LURR theory is a new approach for earthquake prediction, which achieves good results in earthquake prediction within the China mainland and regions in America, Japan and Australia. However, the expansion of the prediction region leads to the refinement of its longitude and latitude, and the increase of the time period. This requires increasingly more computations, and the volume of data reaches the order of GB, which will be very difficult for a single CPU. In this paper, a new method was introduced to solve this problem. Adopting the technology of domain decomposition and parallelizing using MPI, we developed a new parallel tempo-spatial scanning program.
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A second-order dynamic model based on the general relation between the subgrid-scale stress and the velocity gradient tensors was proposed. A priori test of the second-order model was made using moderate resolution direct numerical simulation date at high Reynolds number ( Taylor microscale Reynolds number R-lambda = 102 similar to 216) for homogeneous, isotropic forced flow, decaying flow, and homogeneous rotating flow. Numerical testing shows that the second-order dynamic model significantly improves the correlation coefficient when compared to the first-order dynamic models.
Resumo:
The singular nature of the dynamic stress fields around an interface crack located between two dissimilar isotropic linearly viscoelastic bodies is studied. A harmonic load is imposed on the surfaces of the interface crack. The dynamic stress fields around the crack are obtained by solving a set of simultaneous singular integral equations in terms of the normal and tangent crack dislocation densities. The singularity of the dynamic stress fields near the crack tips is embodied in the fundamental solutions of the singular integral equations. The investigation of the fundamental solutions indicates that the singularity and oscillation indices of the stress fields are both dependent upon the material constants and the frequency of the harmonic load. This observation is different from the well-known -1/2 oscillating singularity for elastic bi-materials. The explanation for the differences between viscoelastic and elastic bi-materials can be given by the additional viscosity mismatch in the case of viscoelastic bi-materials. As an example, the standard linear solid model of a viscoelastic material is used. The effects of the frequency and the material constants (short-term modulus, long-term modulus and relaxation time) on the singularity and the oscillation indices are studied numerically.
Resumo:
采用爆破方法拆除建筑物时,使周围建筑物产生振动的原因是药包的爆破作用和被拆建筑物塌落时对地面的撞击。实测石景山发电厂厂房拆除爆破产生的地面震动结果说明,基础类建筑物爆破产生的震动比建筑物爆破的震动要大,高大集中质量物体塌落撞击震动可能大于炸药爆破产生的震动强度。塌落震动波的主频低。因此,塌落震动可能造成的破坏应引起重视。控制被拆建筑物的解体尺寸可以减少塌落撞击震动强度。
Resumo:
本文较详细地分析了板块运动模拟实验的困难性.提出了用物质密度差代替温度差的实验方法,结合离心技术,研究了地幔对流对板块运动的作用,成功地再现了板块运动的流动图案。 通过对上涌流动微分方程组的分析,本文还建立了模拟实验中“模型”与“原型”之间的相似准则D_e=D_m。
Resumo:
本文从三维弹性力学出发,推导了四边均匀受压简支矩形板的临界载荷公式,并进行了数值计算与经典理论及考虑剪应变薄板理论进行了分析比较。
Resumo:
本文利用拟渠道模型得到简明的分析表达式,求出了放电特性曲线;定义了高频振荡器的输出特性曲线,并作了计算;且由槽路参数将上述两曲线联系起来,定出工作点。为此可预先对任一种气体及高频机判断放电能否维持;可以讨论对工程实践至关重要的阻抗匹配问题以及功率放大规律;并指出π网络适用于氢等离子体而且得到实验证实。
Resumo:
The gliding behavior of edge dislocation near a grain boundary(QB) in copper under pure shear stresses is simulated by using molecular dynamics(MD) method. Many-body potential incorporating the embedded atom method (EAM) is used. The critical shear stresses for a single disocation to pass across GB surface are obtained at values of sigma(c)=23MPa similar to 68 MPa and 137 MPa similar to 274 MPa for Sigma=165 small angle tilt GB at 300 K and 20 K, respectively. The first result agrees with the experimental yield stress sigma(y)(=42 MPa) quite well. It suggests that there might be one of the reasons of initial plastic yielding caused by single dislocation gliding across GB. In addition, there might be possibility to obtain yield strength from microscopic analysis. Moreover, the experimental value of sigma(y) at low temperature is generally higher than that at room temperature. So, these results are in conformity qualitatively with experimental fact. On the other hand, the Sigma=25 GB is too strong an obstacle to the dislocation. In this case, a dislocation is able to pass across GB under relatively low stress only when it is driven by other dislocations. This is taken to mean that dislocation pile-up must be built up in front of this kind of GB, if this GB may take effect on the process of plastic deformation.
Resumo:
选用Ag,Ni两块理想金属,用分子动力学模拟方法研究了以下两种情况下的弯曲过程,进而分析界面对复合材料力学性能的影响:(1)二者在相距足够远以至于两类原子间无相互作用,不形成界面;(2)二者迭放一起取向形成界面。通过模拟这两种情况下的静态弛豫和动态弯曲过程,比较了它们的异同之处。结果表明,界面的存在对复合材料的力学性能影响很大,有时甚至起控制作用。
Resumo:
采用MSC.Mare非线性有限元软件,对激光强化过程中的温度场进行数值模拟,分析了能量密度的变化对激光强化效果的影响。通过温度传感器测量激光强化时材料表面温度的变化来验证数值模拟的结果。模拟值与实测值基本吻合。结果表明,数值模拟结果可作为激光加II艺参数选择的依据。
Resumo:
本书为祝贺郑哲敏先生八十华诞的学术报告会的文集,其中收录邀请报告12篇,定向征文58篇。这些论文涉及爆炸力学、岩土力学、冲击力学、材料力学性能、生物力学、物理力学、海洋工程力学、环境流体力学等几大方面,绝大多数为论文作者科研项目的最新成果。
会议论文 |
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序 | 洪友士; | |||||
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内禀Deborah数在破坏现象中的意义 | 白以龙;汪海英; | |||||
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爆炸波在混凝土夹层结构中传播特性分析 | 段祝平; | |||||
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海洋内波与海洋工程 | 李家春;程友良;范平; | |||||
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郑哲敏先生为推动我国力学和技术科学发展所作的贡献 | 谈庆明; | |||||
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开发深海资源的海底空间站技术 | 曾恒一; | |||||
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微系统动力学研究的一些新进展 | 赵亚溥; | |||||
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爆炸近区空气冲击波规则反射和非规则反射 | 周丰峻;陈叶青;任辉启; | |||||
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椭圆函数的精细积分算法 | 钟万勰;姚征; | |||||
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量子蒙特卡罗法的研究 | 孙祉伟; | |||||
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拟Hamilton系统随机平均法在活性布朗粒子动力学研究中的应用 | 朱位秋;邓茂林; | |||||
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二个二阶张量的各向同性标量函数的广义坐标 | 王文标;段祝平; | |||||
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弹性杆轴向碰撞波动问题理论分析 | 马炜;刘才山;黄琳; | |||||
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两个可变形结构的相互碰撞——模型与验证 | 余同希;阮海辉; | |||||
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结构动力计算中自由度减缩方法概述 | 刘彬;丁桦;梁乃刚; | |||||
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弹塑性系统动力行为探讨 | 杨桂通; | |||||
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SINGULARITY THEORY ON BUCKLING OF COMPRESSIBLE ELASTIC SLENDER RODS | 张义同;谢宇新; | |||||
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GCr15钢超高周疲劳断口观察与裂纹起源分析 | 周承恩;洪友士; | |||||
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纳米尺度毛细作用学——纳米物理力学的新领域 | 朱如曾; | |||||
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METALLIC CELLULAR SOLIDS UNDER IMPACT LOADING | H.Zhao;S.Abdennadher;I.Elnasri; |
Resumo:
本书收录关于力学领域的论文301篇。内容包括:回顾20世纪力学在中国的发展,描绘了2000年中国和世界在力学各主要领域的发展现状;展望力学在21世纪的发展方向,探论新世纪中可能面临的新的重大力学等问题。
![]() | 前言 | 白以龙;杨卫; | |||||
![]() | 力学学科《学科发展与优先领域战略研究报告》 | ||||||
![]() | 世纪之交对力学的回顾、展望和想象 | 白以龙; | |||||
![]() | 计算流体力学中发展物理分析的几个问题 | 张涵信;李沁;宗文刚;张来平; | |||||
![]() | 非对称Riccati方程基于本征解的分析解 | 钟万勰; | |||||
![]() | 实验固体力学近几年的概况 | 伍小平; | |||||
![]() | HIGHER-ORDER COHESIVE ELASTICITY THEORIES OF FRACTURE | Anna Vainchtein; | |||||
![]() | 疲劳短裂纹群体损伤随机特征研究 | 洪友士;郑亮;乔宇; | |||||
![]() | 半浮区热毛细对流及其不稳定性机理 | 胡文瑞;唐泽眉; | |||||
![]() | ZONAL AND CORRELATION ANALYSIS IN SWEPT SHOCK/BOUNDARY LAYER INTERACTIONS | 邓学蓥; | |||||
![]() | 经典约束系统动力学的研究进展 | 梅凤翔; | |||||
![]() | 复杂系统的非线性动力学问题 | 陆启韶; | |||||
![]() | 时滞受控系统动力学研究进展 | 胡海岩;王在华; | |||||
![]() | 力学与航天器工程 | 马兴瑞;苟兴宇;周志成; | |||||
![]() | 采矿工程中的力学问题与分析 | 谢和平; | |||||
![]() | CHALLENGING PROBLEMS IN FAILURE ANALYSIS OF DUAL-PHASE MATERIALS: CYCLIC MICRO-PLASTICITY AND SMALL FATIGUE CRACK TIP BEHAVIOR | ||||||
![]() | 力学与国防科技 | 周丰峻; | |||||
![]() | 流体力学和气动热弹性力学新一代反命题的研究 | 刘高联; | |||||
![]() | 含灰气体近壁区流动及传热增强机制分析 | 王柏懿;戚隆溪;王超;江先金; | |||||
![]() | 三维定常、二维非定常分离模式及准则研究 | 吕志咏; |