第4届国际物理学中的非线性与湍流过程专题讨论会(IWNTPP-4)

<正> 1 一般情况 由国际纯粹与应用物理联合会(IUPAP)委托苏联科学院主办两年一次的国际“物理学中的非线性与湍流过程”专题讨论会(IWNTPP),这次是第4届,于1989年10月9—22日在苏联的基辅举行.按照IWNTPP的惯例,除苏联学者外,会议的参加者必须是得到苏联科学院的邀请的.这次会议参加者共476人.苏联派出以5位院士为首的强大阵容代表苏联科学院朗道理论物理研究所、空间研究所、复杂问题“控制论”科学委员会,乌克兰科学      

全国动光测力学学术讨论会在杭州召开

根据中国力学学会第四届实验应力分析会议决定,全国动光测力学学术讨论会于1986年11月6日至8日在杭州市举行.来自全国有关高等院校、科研单位和对口器材生产厂的56位代表出席了会议,有32篇论文参加了交流和讨论。会议由浙江省力学学会具体筹办。     

国际等离子体科学与技术会议纪要

"国际等离子体科学与技术会议"于1986年6月4日-7日在北京香山饭店召开。这次会议是由中国力学学会与北京市等离子体学会共同主办的。会议得到了世界各国学者的广泛响应与热情支持,来自加拿大、捷克斯洛伐克、法国、德意志联邦共和国、日本、荷兰、波兰、新加坡、瑞士、英国、美国、苏联以及中国等13个国家的139名代表出席了会议(外国代表44名)。有的国家的学者虽然未能与会,但寄来了学术论文,或用...     

生物固体力学讨论会在西安召开

中国力学学会生物固体力学讨论会于1983年9月12日至19日在西安召开.参加会议的有力学、医学和生物学工作者共约60余人.会议用大部分时间介绍和讨论了与生物固体力学有关的若干基本问题,如可变形体力学基本方程、粘弹性力学基础、骨力学的基本问题与应用、骨力学与电活动、骨的超微结构、生物     

‘99全国固体力学学术会议税简介

１会议概况由中国力学学会固体力学专业委员会主办、哈尔滨工业大学复合材料研究所承办的‘９９全国固体力学学术会议（‘９９ＮＣＳＭ）于１９９９年１月７日～９日在哈尔滨工业大学召开。中科院力学所的王自强研究员和哈工大复合材料研究所的杜善义教授共同主持了会议．出席本次会议的正式代表共有１００余人,部分力学界老一辈专家、学者应邀出席了会议并在大会上作了精彩的报告,其中包括中科院院士、清华大学教授黄克智,中科院院士、中科院力学所研究员、中国力学学会理事长白以龙,中国工程院院士、哈尔滨建筑大学教授王光远,中国工…     

会议消息

’９９全国固体力学学术会议由中国力学学会固体力学专业委员会主办,哈尔滨工业大学复合材料研究所承办的’９９全国固体力学学术会议（’９９ＮＣＳＭ）于１９９９年１月７日～９日在哈尔滨工业大学召开,出席本次会议的正式代表共有１００余人,部分力学界老一辈专家、学者应邀出席了会议并在大会上作了精彩的报告,其中包括黄克智院士,中国力学学会理事长白以龙院士,王光远院士,崔俊芝院士．中国工程院院士黄文虎主持了闭幕式的大会报告．本次学术会议共收到论文１０４篇,会议期间交流了８０篇,其中大会特邀报告１１篇（大会开幕式…     

生物固体力学讨论会在西安召开

中国力学学会生物固体力学讨论会于1983年9月12日至19日在西安召开.参加会议的有力学、医学和生物学工作者共约60余人.会议用大部分时间介绍和讨论了与生物固体力学有关的若干基本问题,如可变形体力学基本方程、粘弹性力学基础、骨力学的基本问题与应用、骨力学与电活动、骨的超微结构、生物 ...     

第一届理性力学讲学讨论会在兰州举行

中国力学学会于一九七九年八月一日至十九日在兰州举办了第一次理性力学讲学讨论会.参加讨论会的有高等院校和科研单位的代表共四十九名.这次会议由“理性力学与力学中数学方法”专业组负责并委托兰州大学具体筹办.会议主要有两个内容:(1)钱伟     

惯性系统与测量专业委员会第七次学术交流会在大理市召开

中国惯性技术学会惯性系统与测量专业委员会于2002年8月28日至9月1日在云南省大理市召开了第七次学术交流会，有关会员单位和学报编辑部共32位代表参加了会议，会议交流学术论文27篇。会前，专业委员会主任委员冯培德院士主持召开了专业委员会委员代表会议，通报了会议准备情况，研究了专业委员会的今后工作。 会议重点介绍和讨论了系统误差研究，GPS、景象匹配、伪卫星、天象、重力等与惯性组合导航技术研究，数字导航技术研究，系统故障检测技术与算法研究等议题。 经过几天的会议交流和讨论，代表们认为本次会议的论文内容充实，观点新…     

第六届全国湍流与流动稳定性学术会议暨第三届全国工程紊流与流动模拟学术会议简介

１会议概况 第六届全国湍流与流动稳定性学术会议暨第三届全国工程素流与流动模拟学术会议于 ２０００年 ５月２４日～２７日在上海大学举行．会议由中国力学学会、中国水利学会、上海大学和交通部科研院河口海岸科学研究中心共同主办．中国科学院院士钱伟长、周恒、张涵信、刘高联,中国工程院院士何友声参加了会议．来自国内和香港地区的２４所高等院校和科研院所的６０多位从事湍流理论和应用的专家、学者在会上交流了近年来湍流理论和应用的最新研究成果． 会议共作大会报告１７个、分组报告４２个．内容涉及流动稳定性理论、湍流基本理…     

Electrogas- and electrohydrodynamic control of gas and liquid jets and flows

The physical and mathematical principles of the method of electrogas-and electrohydrodynamic conversion of electrical signals to pneumatic (hydraulic) signals and vice versa for control of gas and liquid jets and flows in electropneumohydraulic systems are considered. St. Petersburg State Technical University, St. Petersburg 195251. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 2, pp. 25–31, March–April, 2000.     

Fatigue and static strength of notched and unnotched aluminum-alloy and steel specimens

This paper describes a method of presentation of fatigue data on three commonly used aircraft materials, 2024-T3 and 7075-T6 aluminum alloys and normalized SAE 4130 steel, such that variations in fatigue strength with stress-concentration factor can be shown. Comparisons of the fatigue strengths of 2024-T3 and 7075-T6 aluminum are made for the most useful range of stress-concentration factors. Static-strength results of notched and unnotched specimens of the three materials are presented to show how the strength varies with some parameters of the stress concentration. Comparison of the data with one theory for the strength of cracked specimens was made.     

STICTION AND ANTI—STICTION IN MEMS AND NEMS

Stiction in microelectromechanical systems (MEMS) has been a major failure mode ever since the advent of surface micromachining in the 80s of the last century due to large surfacearea-to-volume ratio. Even now when solutions to this problem are emerging, such as self-assembled monolayer (SAM) and other measures, stiction remains one of the most catastrophic failure modes in MEMS. A review is presented in this paper on stiction and anti-stiction in MEMS and nanoelectromechanical systems (NEMS). First, some new experimental observations of stiction in radio frequency (RF) MEMS switch and micromachined accelerometers are presented. Second, some criteria for stiction of microstructures in MEMS and NEMS due to surface forces (such as capillary, electrostatic, van der Waals, Casimir forces, etc.) are reviewed. The influence of surface roughness and environmental conditions (relative humidity and temperature) on stiction are also discussed. As hydrophobic films, the self-assembled monolayers (SAMs) turn out able to prevent release-related stiction effectively. The anti-stiction of SAMs in MEMS is reviewed in the last part. The project supported by the Distinguished Young Scholar Fund of NSFC (10225209), key project from the Chinese Academy of Sciences (KJCX2-SW-L2) and National “973” Project (G1999033103)     

水和水蒸汽热力学物性参数及导数的计算与应用

本文针对现代换热设备设计、两相流动与传热研究的需要,介绍了可供科研使用的水和水蒸汽物性计算方法,完善了计算程序。根据超临界锅炉设计中的超临界水的物性计算,两相流研究和换热设备动态特性研究中对物性导数计算的需要,提供了两个算例,并进行了定性分析。     

Fundamental properties of elasto-plastic matrix and existence and uniqueness of elasto-plastic stress and displacement

Based on the assumption that the yield criterionF(,)=0 is a differentiable surface in stress space and by starting from a specially defined real Euclidean space, the fundamental properties of the elasto-plastic matrix in the incremental theory of plasticity is discussed in detail. By using these results, a convex analysis is made to prove the existence and uniqueness of 1) the distribution of incremental elasto-plastic stress for work-hardening materrials; 2) the displacement distribution for work-hardening materials. Material isotropy is assumed in all discussions of relevant problems.     

Fracture and stability of materials and structural members with cracks: approaches and results

A new alternative approach to fracture problems for materials and structural elements with cracks is set out. It is based on the mechanism of local instability near defects. The approach is used to study the fracture of materials compressed along interacting cracks and the fracture of thin structural members with cracks under tension with allowance for local buckling.__________Translated from Prikladnaya Mekhanika, Vol. 40, No. 12, pp. 18–64, December 2004.     

Fracture and contact problems for and elastic wedge

The paper deals with the plane elastostatic contact problem for an infinite elastic wedge of arbitrary angle. The medium is loaded through a frictionless rigid wedge of a given symmetric profile. Using the Mellin transform formulation the mixed boundary value problem is reduced to a singular integral equation with the contact stress as the unknown function. With the application of the results to the fracture of the medium in mind, the main emphasis in the study has been on the investigation of the singular nature of the stress state around the apex of the wedge and on the determination of the contact pressure.

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Résumé Dans cet essai le problème plan élastostatique de contact pour un coin élastique d'angle arbitraire est étudié. Le milieu est chargé à travers un coin rigide de profil symétrique sans friction. En utilisant la transformation de Mellin le problème de valeurs limites mixtes, est réduit à une équation intégrale singulière où l'effort de contact est la fonction inconnue. Avec l'application des résultats de la rupture du milieu, l'étude est concentrée principalement sur l'investigation de la nature singulière de l'état d'effort autour du sommet du coin et sur la détermination de la pression de contact.

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This work was supported by NSF under the Grant GK 42771X and by NASA under the Grant NGR 39-007-011.     

Drawing and extruding: Theoretical and approximate formulas

Summary The problem of drawing of wires and of strips has been treated in several studies; among these the studies of Sachs seem essential. However, the results deduced according to similar theories are not always in accordance with the experimental results: reduction of area or of thickness are in fact usually smaller than those resulting from the theory. This is in dependance of the fact that Sachs has adopted the Limiting Condition of Yielding by v. Mises, according to which the limit values of stress in traction and compression are equal. More recently other AA. (Alberti, Noto La Diega, Bugini), admitting the Limiting Condition of Yielding by A. (or of the Paraboloid of Revolution) of which we have treated in one of our previous works, attain results tallying with the experience. In the present study the above said subjects are treated as to evidence their unitarian signifiance and clarify their several aspects. The approximate formulas proposed by A. result of easy and quick application. In the same manner are treated other problems, among which the problem of the extrusion (Bagarello, Ammendola).

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Sommario Il problema della trafilatura dei fili metallici e delle strisce di lamiera è stato trattato in diverse Memorie, fra le quali fondamentali sono quelle del Sachs. I risultati dedotti in base a tali studi non sempre però concordano con le risultanze sperimentali: i rapporti di riduzione delle aree o degli spessori sono infatti di norma inferiori a quelli che risultano da tali teorie. Ciò dipende dal fatto che il Sachs ha posto a base dei suoi studi la Condizione di Plastificazione del v. Mises secondo la quale i limiti di resistenza del materiale che si considera alla trazione e alla compressione semplice sono uguali. Più recentemente altri AA. (Alberti, Noto La Diega, Bugini), adottando la Condizione di Plastificazione dell' A. (o del Paraboloide di Rivoluzione), del quale abbiamo trattato in un precedente lavoro, pervengono a risultati più attinenti alla practica. Col presente studio gli argomenti vengono trattati mettendone in evidenza il significato unitario e chiarendone i vari aspetti. Le formule approssimate proposte dall' A. risultano di facile e immediata applicazione. In maniera analoga vengono trattati altri problemi, fra i quali quello dell'estrusione (Bagarello, Ammendola).