真空下气固界面的传热

已知对于真空下的传热稀薄气体起着非常重要的作用。该文给出了稀薄气体在不同克努曾数区域下的气 -固界面间的传热表达式 ,这些表达式中包含了气体反射系数和热适应系数。文中讨论了平行平板、同轴圆柱表面和同心圆球表面的情况 ,给出了不同传热区域热流依照克努曾数倒数关系变化的数值计算结果     

Partial melting at interfaces and graln boundaries for high-strain-rate superplastic materials

The present paper describes partial melting at matrix/reinforcement interfaces and grain boundaries for high-strain-rate superplastic metallic materials. It is suggested from the mechanical testing results that partial melting is associated with the deformation mechanisms of the high-strain-rate superplasticity. DSC measurements and TEM observations reveal that solute additions are segregated at the interfaces and grain boundaries, so that partial melting occurs at elevated temperatures. This supports the concept of the accommodation helper mechanisms such as the accommodation by a liquid phase. However, when a liquid phase is continuous and thick, intergranular decohesion is caused at liquid interfaces and grain boundaries. Therefore a discontinuous and thin liquid phase is required both to play a vital roll as an accommodation helper and to limit intergranular decohesion.     

含电转气技术的电气耦合系统优化运行

在低碳经济背景下,风电、光伏的快速发展促进了电力工业低碳化的发展进程,但弃风、弃光问题愈发严重。电转气(P2G)技术的出现为解决可再生能源消纳问题提供了新思路。考虑减少碳排放和消纳弃风,提出一种含P2G与燃气轮机双向耦合的电-气-电能源循环的电气耦合系统低碳经济优化运行模型。模型以经济成本和碳交易成本之和最小为优化目标,并考虑了弃风惩罚成本以及P2G实现能源转换过程中的经济效益和环境效益,协调经济性与低碳性的同时实现了多目标问题的单目标化。通过对包含电转气和不含电转气两种场景下的系统进行算例分析,验证了优化模型的有效性和优越性。     

A crystal plasticity theory for latent hardening by glide twinning through dislocation transmutation and twin accommodation effects

Imagine a residual glide twin interface advancing in a grain under the action of a monotonic stress. Close to the grain boundary, the shape change caused by the twin is partly accommodated by kinks and partly by slip emissions in the parent; the process is known as accommodation effects. When reached by the twin interface, slip dislocations in the parent undergo twinning shear. The twinning shear extracts from the parent dislocation a twinning disconnection, and thereby releases a transmuted dislocation in the twin. Transmutation populates the twin with dislocations of diverse modes. If the twin deforms by double twinning, double-transmutation occurs even if the twin retwins by the same mode or detwins by a stress reversal. If the twin deforms only by slip, transmutation is single. Whether single or double, dislocation transmutation is irreversible. The multiplicity of dislocation modes increases upon strain, since the twin finds more dislocations to transmute upon further slip of the parent and further growth of the twin. Thus, the process induces an increasing latent hardening rate in the twin. Under profuse twinning conditions, typical of double-lattice structures, this rate-increasing latent hardening combined with crystal rotation to hard orientations by twinning is consistent with a regime of increasing hardening rate, known as Regime II or Regime B. In this paper, we formulate governing equation of the above transmutation and accommodation effects in a crystal plasticity framework. We use the dislocation density based model originally proposed by Beyerlein and Tomé (2008) to derive the effect of latent hardening in a transmuting twin. The theory is expected to contribute to surmounting the difficulty that current models have to simultaneously predict under profuse twinning, the stress-strain curves, intermediate deformation textures, and intermediate twin volume fractions.     

水布垭工程物资部物资供应管理对EIS的要求

EIS(Exeeutive Information System)集管理信息科学的研究成果和最新的计算机应用技术于一体，是计算机信息系统发展史上的一个新的里程碑。借助于EIS，高层管理者可以及时获取组织内外与经营、管理、决策最为相关的重要信息，根据需要，EIS还附带有电子邮件(E-mail)、文字处理(Word Processillg)、计算机媒体会议(eomputer coufereneing)、专用的决策支持系统(SDSS)和专家系统(ES)等功能，以便能更好地支持管理者的决策，主要就水布垭工程物资供应管理对EIS的要求进行研究。     

气-固表面多原子分子振动能量传递过程的新处理法

气固振动能量传递过程新处理法的适用性巳被许多反应体系所证实。文中系统而简要地阐述了它的物理图象、基本假设和计算公式。所提新观点也有助于澄清诸如能量传递效率、催化作用本质和能量调节系数等概念。     

Accommodation in the formal world of mathematical thinking

ABSTRACT

In this study, we examined a mathematician and one of his students’ teaching journals and thought processes concurrently as the class was moving towards the proof of the Fundamental Theorem of Galois Theory. We employed Tall's framework of three worlds of mathematical thinking as well as Piaget's notion of accommodation to theoretically study the narratives. This paper reveals the pedagogical challenges of proving an elegant theory as the events unfolded. Although the mathematician was conscious of the students’ abilities as he carefully made the path accessible, the disparity between the mind of the mathematician and the student became apparent.     

藏彝走廊“藏回”文化特征探析——以迪庆“藏回”为例

通过对云南迪庆藏回族群文化特征的描述与分析,展现了藏彝走廊丰富多彩的民族文化格局,同时对民族文化调适也进行了探讨,并剖析了其中的规律性。     

人工晶体前移与人眼屈光调节关系的研究

基于Hwey-Lan Liou眼模型,采用ZEMAX光学设计软件实现光线追迹的方法研究了人工晶体在眼内的前移与人眼屈光调节之间的关系.结果表明：人工晶体每前移一定的距离,人眼所获得的屈光调节量不恒定;调节量大小依赖于眼轴长度和所需植入的人工晶体,特别是眼轴长度;对于不同眼轴长度术眼中的人工晶体前移,人眼所获得的屈光调节量与眼轴长度呈负相关.     

人眼晶状体调节机制和力学

晶状体是人眼屈光系统的核心,其视觉调节过程由睫状肌、悬韧带和晶状体共同实现:通过睫状肌牵引悬韧带运动,引起晶状体变形(变凸或扁平),从而改变眼睛的屈光力,使得眼睛聚光的焦点准确地落在视网膜上,最终产生视觉.晶状体的视觉调节从本质上说是一个力学问题,调节过程的实现与视觉质量紧密相关;同时调节机制也是最常见的眼部老化退行性疾病——老视的核心问题.本文介绍了晶状体调节的各种理论假说及其发展,并概述了晶状体的力学性能.