正交异性层合圆柱厚壳静、动态问题的分析解

本文抛弃任何有关位移或应力模式的假设,在柱坐标系下对圆柱型正交异性体建立其状态方程。对层合圆柱厚壳利用Cayley-Hamilton定理一次求解全部未知量。无论层数多少,最后都归结为求解三元一次代数方程组。此解满足所有弹性力学方程并计及了全部弹性常数,可得到任意需要的精度。     

叠层双曲率厚壳静、动态问题的分析解

本文抛弃任何有关位移或应力分布的假设,在正交曲线坐标系下,对正交异性双曲率厚壳建立其状态方程。根据层问应力和位移协调条件,对具有正交异性层的周边简支的层合双曲丰厚壳的静力和动力问题,利用Cayley-Hamilton定理一次求解全部未知量。无论层数多少,最后都归结为只需求解三元一次代数方程组。此解满足所有弹性力学基本方程,并计及了全部弹性常数。可得到任意需要的精度。数值结果与文献[3]及[6]作了对比,结论令人满意。     

具有自由边的层合开口柱壳弯曲问题的解析解

从三维弹性力学基本方程出发，通过假设自由边的边界位移函数并选择适当的级数形式解函数，建立了正交异性层合开口柱壳的状态方程，给出了具有自由的层合开口柱壳的解析解．此解计及了正交异性材料的所有弹性常数，且满足层合壳的基本方程和层间连续条件．为证实本文方法的有效性，给出了数值算例，并与解析解和半解析解模型的结果作了对比，结果令人满意．     

压电层合板壳剪切变形理论

提出了一种压电层合板壳的一阶剪切变形理论,采用Ｈａｍｉｌｔｏｎ原理、压电理论和层合板壳的一阶剪切变形板壳理论,推导了压电层合板壳系统的运动方程,根据一阶剪切变形理论,得到压电压合壳的应变位移关系;并由复合材料板壳的广义内力公式和压电本构关系,导出压电层合壳的广义内力－位移－电场关系;利用Ｈａｍｉｌｔｏｎ原理进行了变化推导,得到压电层合板壳剪切变形理论的运动方程,以及力学和电学边界条件。该理论可应用     

压磁压电层合复合材料圆柱壳表面局部分层屈曲

摘要：
基于复合材料层合壳理论,利用压磁压电纤维材料的本构关系,考虑在温度和电场、磁场作用下,推导含压磁压电材料的局部非对称分层子层壳的总势能及屈曲控制方程.分析子层屈曲时,考虑了面内横向位移.通过对不同铺层形式的计算,给出了温度、电场、磁场荷载作用下,压磁压电复合材料层壳的几何参数、物理参数对任意方向椭圆形的局部分层屈曲临界应变值的影响规律. 关键词：
压磁压电复合材料; 复合材料层合圆柱壳; 局部分层屈曲; 温度载荷; 电场强度; 磁场强度; 临界应变 中图分类号： O 341
文献标志码： A     

任意厚度层合圆板的轴对称弯曲

从三维弹性力学基本方程出发,建立了横观各向同性层合圆板轴对称弯曲问题的状态方程,并给出问题的解析解。此解满足弹性力学全部方程,计及了所有独立的弹性常数,并满足层间连续性条件。     

强厚度叠层闭口柱壳轴对称问题的精确解

抛弃任何有关应力或位移模式的人为假设,在轴对称情况下,对强厚度叠层闭口柱壳建立其状态方程。给出薄的、中等厚度的以及强厚度的叠层闭口柱壳的静力、动力和稳定问题的精确解。此解满足所有弹性力学方程,并计及了全部弹性常数。任意需要的精度均能得到。     

任意厚度叠层圆柱壳动力响应的状态变量法

基于三维弹性力学基本方程,通过引入状态空间理论,建立了叠层闭口柱壳在任意荷载作用下的状态方程,并给出在简谐荷载作用下动力响应问题的解析解。此解满足所有边界条件和层间连续条件,适合任意厚跨比。由于状态方程中的诸力学量正好是叠层壳的层间必须协调的应力和位移诸量,因此该文方法便于求解叠层结构。算例表明,利用该文方法可以方便地进行动力响应分析。     

具有固支边的功能梯度压电矩形板静力解

从三维弹性理论和压电学理论出发,通过假设满足边界条件的位移函数,推导出具有固支边的功能梯度压电板的状态方程,并运用状态变量法以及层间连续条件,在每一层端点处应用配点法,给出了满足周边和上、下表面所有边界条件的解析解。该文将状态变量法运用在具有固支边的功能梯度压电材料的静力问题上,给出了不同梯度分布压电板在具有固支边界条件下的静力解,讨论了梯度变化函数对挠度和应力场的影响,为功能梯度压电结构设计及材料优化提供一定参考依据。     

强厚度叠层闭口悬臂圆柱壳轴对称问题的精确解

抛弃任何有关位移或应力模式的人为假设，在轴对称情况下导出正交异性体的状态方程。给出叠层闭口悬臂圆柱壳轴对称问题的精确解。此解满足所有基本方程，包含了全部弹性常数，可得到任意需要的精度。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

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

An Index mechanism for multi-scale view in spatial databases

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the