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1.
研究具有弯折结构的铜微互连线在不同条件下的原子迁移现象,基于原子通量散度理论构建了结构-热-电耦合的多物理场有限元模型,静态分析了铜微互连线结构的电流、温度及应力分布情况,动态模拟了原子迁移全过程.分析了原子迁移过程中电迁移、热迁移及应力迁移各自的作用,揭示了电流密度、环境温度、退火温度和缺陷对原子迁移行为及寿命的影响规律.分析仿真结果发现:电迁移和应力迁移在原子迁移过程中促进了孔洞的生长且占主导作用,热迁移起到了一定抑制作用但所占比例不大.  相似文献   

2.
针对雪地环境电磁散射的特殊性、复杂性,建立土壤与雪层相对介电常数模型,分析频率和湿度对土壤和雪层有效相对介电常数的影响。以高斯分层粗糙面模拟有雪层覆盖的土壤表面,基于考虑层间多次散射的微扰法(small perturbation method,SPM)定量计算土壤层的相对介电常数、粗糙度,雪层的厚度对雪地环境后向电磁散射的影响,并结合土壤与雪层相对介电常数模型分析对雪层和土壤层相关信息获取的可行性。研究结果为雪层厚度、融化速度以及雪层下地形地貌的探测提供了理论依据。  相似文献   

3.
含分层损伤复合材料层合板非线性热弹性分析   总被引:3,自引:1,他引:3  
应用含分层损伤复合材料层合板的高阶理论精化有限元模型,对「0/90」s对称正交铺设层合板在热成型过程中的热变形及残余应力进行了非线性热弹性分析,考虑了材料弹性性能和热性质依赖于温度变化的影响,得到一些对工程应用有参考意义的结果。  相似文献   

4.
土壤中热、湿、气及溶质耦合迁移的数学模型   总被引:1,自引:0,他引:1  
从连续介质力学出发,应用Whitaker提出的局部体积平均法,建立了一个描述植物生长的土壤中热、湿、气及溶质耦合迁移的多场数学模型,以揭示非饱和土壤内复杂的传输机理.此模型中考虑了植物根系对水分、热量、气体和溶质的吸收或排放,同时在边界条件中反映了植物冠层对土壤表面遮阳的影响.因此,该模型相对于已有的其他模型来说,所包含的物理机制更加完备,并且它还具有可解性.  相似文献   

5.
本文从热湿迁移机理出发,通过在液相渗流中引入毛细滞后的影响,采用液相运动的最小梯度假设,建立了未饱和含湿多孔介质在考虑毛细滞后效应时传热传质的较普遍的模型理论.并对方程中的热湿迁移特性系数进行了分析,为进一步发展确定热湿迁移特性的有效实验方法提供了依据。  相似文献   

6.
本文从热湿迁移机理出发,通过在液相渗流中引入毛细滞后的影响,彩用液相运动的最小梯度假设,建立了未饱和含湿多孔介质在考虑毛细滞后效应时传热传质的较普遍的模型理论,并对方程中的热湿迁移特性系数进分析,为进一步发展确定热迁移特性的有效实验方法提供了依据。  相似文献   

7.
 采用指数型粗糙面模拟实际的粗糙雪层和土壤表面,运用矩量法(MOM)结合基尔霍夫近似(KA)的混合算法研究了雪层覆盖土壤面的电磁波透射特征.混合算法将雪层表面划分在MoM区,土壤面划分在KA区,数值计算得到了透射系数的角分布曲线,分析了雪层和土壤表面的高度起伏均方根、雪层类型、土壤湿度、雪层厚度对透射系数的影响.结果表明,雪层表面高度起伏均方根、雪层类型、土壤湿度对透射系数有显著影响,而土壤表面高度起伏均方根和雪层厚度对透射系数影响较小.  相似文献   

8.
自然降雪积覆在绝缘子表面对输电线路外绝缘构成了严重威胁。研究覆雪对输电线路绝缘子沿面电场分布的影响,对于揭示覆雪绝缘子电场分布规律及其影响因素、减轻覆雪对外绝缘的危害具有重要的工程价值。对复合绝缘子FXBW-110/70建立了覆雪绝缘子的二维非对称有限元模型,研究了覆雪厚度、雪层相对介电常数、空气间隙位置和长度对绝缘子沿面电场的影响规律。结果表明:相对于清洁绝缘子,覆雪严重畸变了绝缘子沿面电场分布,其中靠近电源侧和接地侧绝缘部分的电场畸变程度最严重;沿面电场畸变程度随着覆雪厚度和雪层相对介电常数的增大而增大;由于空气间隙承担了绝缘子大部分压降,其电场强度明显高于覆雪层的电场强度。  相似文献   

9.
通过对非饱和土壤内部热、水、气耦合迁移特性,植物根系吸水特性及植物蒸腾的描述,建立了反映土壤-植物-大气复合系统内温度、水分、含气量等的动态变化过程的一般数学模型.作为一个算例,还用该模型对利用地下多孔埋管引入冷凝水来加热与灌溉土壤的效果进行了数值模拟.模拟结果一方面反映了模型的可行性,另一方面亦为植物生长的热物理环境的优化设计提供了依据.  相似文献   

10.
蒸发状况下土壤中热湿迁移的非稳态数值模拟   总被引:1,自引:0,他引:1  
给出了计算不饱和土壤中热湿迁移的二维数学模型,对蒸发状况下土壤中的热湿迁移过程进行了非稳态数值分析,探讨了土壤热湿迁移对环境参数和土壤内部参数(质地、结构参数)的动态响应特性。  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

15.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

16.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

17.
18.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

19.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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