Stresses in thin films for hyperfiltration

An elastic and a viscoelastic analyses have been performed to determine the extent to which thin polymer films used in “hyperfiltration” process of desalination of brackish or sea water may be stressed. It was found that if pores of the size comparable to the thickness of the film exist in the rigid supporting material, stress of the order of magnitude comparable to the ultimate strength of the film may be induced.     

On the electromagnetic detection of the thickness of a coal or lignite seam with slate backing

The use of two small current loops for probing the thickness of a two-layer earth structure is discussed. The thickness and the conductivity contrast can be found by zeroing the secondary magnetic field on the axis of the receiving loop. The inversion from the measured data to the layer thickness proves that our procedure is simple. The whole method can be incorporated into an automated mining machine for sensing a coal or lignite seam with a slate backing.     

On Incremental Deformations of Initially Stressed Media with Couple Stresses

A two-dimensional theory for the incremental deformations of an initially stressed continuum with couple stresses is established in this paper. As applications of theory, the problems of internal instability and wave propagation are studied. It is found that the otherwise non-dispersive waves become dispersive, and additional local modes of buckling and vibratory motion are observed. To complete the theory, a stress function formulation of equations is also presented.     

Stresses in a radially constructed rotating cylinder

The dynamic radial stress distribution in a circular hollow cylinder, bonded to a rigid core at its inner surface and prevented from outward displacement by a smooth rigid cylindrical wall, due to a rotational motion with a variable angular velocity, is analyzed.The stress as a function of radial distance and time is determined. A sample calculation shows that the stress changes from tension at the inner surface to compression at the outer surface, as would be expected. The variation of stress vs radial distance is plotted for several instants of time. Also, the stress vs time for various radial positions is plotted.     

自然资源资产负债表研究进展综述

“探索编制自然资源资产负债表,对领导干部实行自然资源资产离任审计”对缓解中国经济增长与资源、环境之间的矛盾,实现资源可持续利用、社会经济可持续发展与生态文明建设具有重要意义。由于自然资源资产负债表是中国近期提出的全新概念,现阶段自然资源资产负债表编制存在着诸多问题与障碍。本文首先通过对2014年1月1日至2017年12月31日“中国知网”收录的围绕“自然资源资产负债表”为研究核心的295篇文章进行分析,从文献年代、作者、研究单位、载文期刊以及研究内容等角度阐明自然资源资产负债表的研究概况;然后从自然资源资产负债表理论研究、方法研究和实践研究三大方面具体阐述自然资源资产负债表的研究现状及成果。研究结果表明：自然资源资产负债表相关研究现处于初期阶段,相关理论基础和方法体系并不完善;研究属于多学科交叉研究,研究领域存在明显合作现象;自然资源资产负债表构成要素、核算方法与表式结构是现阶段的研究热点;自然资源资产负债表编制技术体系的基本框架已经形成;但对自然资源资产负债表编制理论基础的研究十分匮乏,自然资源资产负债界定与核算、自然资源资产与负债价值化等一系列关键问题的方法论研究将成为今后研究的重点。     

Stresses and deformations in pipe flanges subjected to creep at high temperatures

Various solutions have been made for determining the stresses in pipe flanges using the theory of elasticity (I). There are many cases, however, of pipe flanges which are subjected to stresses and at the same time a high temperature such that creep occurs.This paper gives an analysis of the stresses and deformations produced in a circular ring of rectangular cross section subjected to twisting couples uniformly distributed along its center line. Such a solution will also give an approximate analysis of the pipe flange. This approximation is justified in view of the complexity of the problem and the uncertainties still present in the fundamental creep-stress relation for metals. In the solution of this problem a deflection theory is also developed for straight beams subjected to bending accompanied by creep.     

自闭症家庭压力体验的质性研究——以湘潭地区为例的调查研究

自闭症是一种严重的精神发育障碍.患了自闭症的孩子通常都无法自立于这个社会,因此自闭症孩子的家庭面临着很多人无法想象的压力.本研究通过半结构式访谈的方法,对6位湘潭市亲园培智学校的自闭症儿童家长进行了深度访谈,旨在了解自闭症家庭的具体压力来源以及家长的压力体验.研究发现:自闭症家庭压力的来源主要是人手不足、经济压力、精神压力,其中精神压力体验最为强烈;面对各种压力,自闭症家庭大多数是采用埋怨、消极、悲观的态度应对方式,虽然也尝试用积极的方法去面对困境,但是依然常常体验到无助感.     

国家资产负债表研究进展及其对自然资源资产负债表编制的启示

探索编制自然资源资产负债表是党的十八届三中全会作出的重大决定,是资源与环境保护的重要举措。国家资产负债表是国家治理的重要分析工具,对于编制自然资源资产负债表具有重要的参考价值。自然资源资产负债表作为一个崭新的概念,目前其编制工作面临着理论基础不扎实、资产与负债的界定不清晰、相关概念与内涵不确定以及价值化体系不完善等一系列问题。着眼于此,本文首先初步探讨了国家资产负债表的基本概念与内涵,然后详细梳理了国内外国家资产负债表的发展历程,特别是有关自然资源项的核算,概括分析了国家资产负债表的一般形式以及估值方法。在此基础上,最后借鉴国家资产负债表相关经验,就自然资源资产负债表表式的基本概念、资产与负债的确认原则以及自然资源资产的核算方法等基本问题提出了具体建议。