Analysis of reservoir water quality using fuzzy synthetic evaluation

A general methodology for fuzzy synthetic evaluation is developed and illustrated with a case study of trophic status assessment for Fei-Tsui Reservoir in Taiwan. The historical data base was collected from the management agency of Fei-Tsui Reservoir from 1987 to 1996. In fuzzy synthetic evaluation, the classification is determined by a matrix operation of the weighted vector with the fuzzy evaluation matrix. After all individual membership functions of evaluated factors have been determined, the fuzzy evaluation matrix can be established. The weighted vector is determined by the analytic hierarchy process method (AHP). The results of this investigation show that the long-term change of water quality and the overturn phenomena cannot be observed with the Carlson index from 1987 to 1992 but is expressed by fuzzy synthetic evaluation. Fuzzy synthetic evaluation is better suited than the Carlson index to rating the trophic status of self-sustaining lakes. Interpretation of the results can provide valuable information to decision makers and aid reservoir management.     

嵌岩桩理论研究和设计中的几个问题

明确嵌岩桩的定义和分类,对嵌岩桩的承载机理、临界嵌入深度、设计理论和数值模拟方法等问题进行讨论,并对未来的工作进行论述。     

煤造石油与煤成油理论关系研究进展综述

综述了煤造石油的研究进展。煤加氢液化研究结果表明挥发分、Ｈ与Ｃ比值、煤级、催化剂是影响煤炭液化的重要因素;对煤造石油与石油玩机成因说、煤造石油与煤一理论之间的联系进行了评述,现代含煤岩系煤成油研究得出的结论与煤造石油实践得出的结果近似一致,一些大油田分布带与大构造活动区带近于一致,由此使人们得出了类似于Ｆ－Ｔ法合成的石油无机成因理论。     

论不同模式大气中的静力适应过程

为了研究大气静力平衡适应过程的本质,利用波动理论和能量转换角度,分别对完全可压缩的等温大气模型、滞弹近似下的等温大气模型和层结中性大气模型进行研究比较.结果表明：大气静力平衡适应过程的本质是声波和混合声重力波对扰动能量的频散过程,滞弹近似模型和层结中性模型均不能完全描述此适应过程;在波动假设下,此三类大气模型中扰动物理量之间的偏振关系同波动的性质有关,气团的运动方程均为椭圆方程,声波和混合声重力波对气团运动的作用差异较显著.
大气静力平衡适应过程中扰动能量以有效势能、有效弹性势能、动能或波动能量的形式存在并相互转换;扰动有效势能与其他形式能量之间的转换与混合声重力波或者重力内波有关,扰动有效弹性势能与其他形式能量之间的转换与声波有关.在完全可压缩的等温大气模型中,扰动有效势能增加1个单位,其中69.9%来自扰动垂直动能,其余30.1%来自扰动有效弹性势能.     

Characteristics of eigen-system for flexural gravity wave problems

For a class of boundary value problems associated with flexural gravity waves, characteristics of the eigen-system are analysed which are used to study the convergence of the expansion formulae in both cases of single and two layer fluids in water of finite and infinite depths. Using Green’s function technique, the spectral representations of the vertical eigenfunctions are obtained which are used along with the orthogonal mode-coupling relations to prove the convergence of the expansion formulae. Using the expansion formulae flexural gravity wave scattering due to multiple articulations in the presence of compression are investigated. The problem is studied in both the cases of single-layer and two-layer fluids in finite water depth. Effects of compressive force, stiffness of the connectors, length of the elastic plates and water depth, position of interface on wave scattering by articulated plates are studied by analysing the reflection and transmission coefficients. This procedure of proving the convergence of expansion formulae is independent of water depth. The concept and methodology for dealing with wave-structure interaction problems discussed here can be generalised to deal with problems of similar nature arising in the broad area of mathematical physics and engineering.     

On the robustness of the toroidal velocity theorem

In dynamo theory the toroidal velocity theorem in its classical version (Elsasser, Phys. Rev. 1946, vol. 69, pp. 106–116, Bullard and Gellman, Phil. Trans. R. Soc. Lond. 1954, vol. A247, pp. 213–278) rules out dynamo action in a spherical conducting volume provided that the fluid is incompressible, the conductivity is uniform, and the velocity field is purely toroidal. We prove in this note that this result is robust in the sense that slight compressibility of the fluid, small non-radial variations and even large radial variations in conductivity, and the presence of a small non-toroidal velocity component do not invalidate the theorem. Moreover, by proper choice of the conductivity distribution modelling the conducting volume, small deviations from spherical symmetry of the conductor can also be taken into account.     

有限元模拟弹性位错的等效体力方法

计算地震位错造成的位移场和应力场,对于估计大地震引起的后续地震活动发展趋势十分重要.本文提出在弹性位错问题的有限元模拟中,用等效体力代替位错源,从而在构建几何模型时不用包含断层,却可以处理包含任意复杂断层的问题,极大降低建模的难度.使用此方法,本文计算并讨论了在球形地球模型下2011年日本Tohoku-Oki特大地震对华北地区断层的影响,结果表明此次地震使华北主要断层趋于稳定.     

前板可旋转的双垂板结构水动力特性的理论研究

振荡水柱波能转换装置的最大转换效率往往受到腔内水柱共振机制的直接影响。通过对装置的基本结构进行简化,提出了一种前墙可绕固定轴旋转的双垂板式结构系统,旨在通过前墙的旋转运动进一步加剧水柱的振荡,从而对腔内水柱的共振机制进行调节和控制。基于线性波理论,采用匹配特征函数展开法对波浪与双垂板结构的相互作用进行理论研究,针对流场在结构物尖角附近的奇异性特征,将公共界面上的速度分布基于切比雪夫多项式近似展开,并应用区域间的速度与压力连续条件进行求解。通过分析结构的几何参数对反射透射系数、平均波面高程、前墙旋转振幅以及前墙与水面间相位差的影响,深究其共振机理,为振荡水柱波能转换装置的效率优化机制提供理论依据。结果表明,在所研究的波浪频率范围内,前墙的自由旋转运动会加剧板间的平均波面高程,应用于波浪能转换装置中能进一步拓宽高效频率带宽。