A Continuum Approach to Two-Phase Porous Media

An axiomatic method is used to derive governing equations of isothermal mechanics of two-phase porous media. The first and second axioms of continuum are formulated in order to define the continuum approach to the problem. A dimensionless number is introduced to simplify the general equations and to obtain the equations of Darcian mechanics. Several aspects of the method and the results are discussed.     

Boundary mixed variational inequality in friction problem

IntroductionThestaticffichonProblemdiscussedinthespaperisakindofnonlinearunilateralboundalvaluePIDbleth.Itiswell-knownthatordinarylinearelliphcboundaryvalueProblemoftencormspondstOCertainlinearvariahonalequahon,theexistenceanduniquenessofitssolutioncanbeobtainedbyusingthein-MilgramtheoremorBabuskatheorem.HoweverthisunilateralboundalvallueProblemcormSPOndstoakindof"dxedvariahonalinequality['J.Sinceitcontainsthenonlinearindifferentialfunchonal,theusuallinearizationmethodsareuseless.Thereby…     

Can Torsion Play a Role in Angular Momentum Conservation Law?

In Einstein-Cartan theory, by the use of thegeneral Noether theorem, the general covariantangular-momentum conservation law is obtained withrespect to the local Lorentz transformations. Thecorresponding conservative Noether current is interpreted asthe angular momentum tensor of the gravity-matter systemincluding the spin density. It is pointed out that,assuming the tetrad transformation given by eq. (15), then torsion does not play a role in theconservation law of angular momentum.     

Unsymmetrical bending problems for the annular and circular thin plates under various supporting conditions (I)

In this paper we consider the nonlinear and unsymmetrical bendings of annular and circular thin plates under various supports. The uniformly valid asymptotic solutions have been derived by means of the perturbation method presented in [7].     

A Simple Derivation of Josephson's Formulae in Superconductivity

A simple and general derivation of Josephson's formulae for the tunneling currents is presented on the basis of Sewell's general formulation of superconductivity in relation to off-diagonal long-range order (ODLRO).     

低渗透微尺度孔隙气体渗流规律

微尺度条件下气体流动特性的研究是现代渗流力学前沿领域之一．分析了低渗透岩石饱和气体渗流实验结果,探索了微尺度孔隙气体渗流规律,探讨了气体非线性渗流力学机理,发现了低渗透岩石微尺度孔隙气体与液体渗流遵循同一形式的运动定律,建立了气体与液体非线性运动定律统一模型．结果表明：新模型与实验结果吻合很好,为微尺度孔隙气体微流动特性研究提供了新的理论依据,对工程地质环境保护及地下流体资源开发有重要指导意义．     

The Boyer–Moore–Horspool heuristic with Markovian input

The Boyer–Moore–Horspool string‐matching heuristic is an algorithm for locating occurrences of a fixed pattern in a random text. Under the assumption that the text is an independently and identically distributed sequence of characters, the probabilistic behavior of this algorithm was investigated by Mahmoud, Smythe, and Régnier [Random Struct Alg 10 (1997), 169–186]. Here, we obtain similar results under the assumption that the text is generated by an irreducible Markov chain. A natural Markov renewal process structure is exploited to obtain the asymptotic behavior of the number of comparisons. Under suitable normalization, it is shown that a central limit theorem holds for the number of comparisons. The analysis is completely probabilistic and does not use the shift generating function. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 18: 153–163, 2001     

一种氯苯基硅油的合成及其摩擦磨损性能研究

合成了一种甲基封端、侧基含五氯苯基取代基团的有机聚硅氧烷(CPSO),考察了CPSO的粘温性能、倾点、饱和蒸气压及热稳定性能.采用OptimolSRV型微动摩擦磨损试验机评价了CPSO及空间用润滑油全氟聚醚(PFPE)和磷嗪(X-1P)在常温常压下用于GCr15/CuSn合金摩擦副润滑剂的摩擦磨损性能;采用CZM型真空摩擦试验机评价了3种润滑油在真空条件下用于GCr15/CuSn合金和GCr15/9Cr18摩擦副润滑剂的摩擦磨损性能.结果表明:在真空和常温常压条件下,CPSO的减摩和抗磨损性能均优于PFPE及X-1P;与此同时,CPSO具有极低的饱和蒸气压、很低的热挥发损失以及较好的热稳定性和低温流动性.故其在空间飞行器械运动部件润滑领域具有广泛的应用前景.     

多孔介质自发渗吸关键问题与思考

多孔介质自发渗吸现象普遍存在于自然界和工业应用领域, 深入研究其微观流动机理及宏观渗流规律具有重要的科学和工程价值。由于受多孔介质物理属性、流体性质、边界条件等多种因素的影响, 自发渗吸机理及渗流规律难以厘清。目前, 已有众多物理实验、理论分析及数值模拟等方法对多因素影响下的自发渗吸过程进行了广泛而深入的研究。本文就该领域存在的关键问题及最新进展进行梳理分析并提出若干思考, 以期对多孔介质自发渗吸的理解和未来研究工作提供一定的借鉴。