X70管线钢DWTT试样的分层裂纹及其断口评价

通过对管线钢不同温度的落锤撕裂试验和微观断口分析,研究了DWTT试样断口的分层裂纹及其对断裂的影响.结果表明,分层裂纹是受力变形时管线钢内部的薄弱界面受到三维应力作用的结果.分层裂纹出现于主裂纹起裂或加速之前,裂纹稳定扩展或减速时不会产生新的分层裂纹.分层裂纹的数量、张开程度和分层裂纹间距与主裂纹起裂或加速时的应力状态有关,而分层裂纹的长度与裂纹扩展时裂尖的应力状态有关.分层裂纹表面为解理形貌,解理面较大.韧脆转变温度以下的脆性断裂断口或韧脆转变温度附近混合型断口的脆性断裂区,不出现分层裂纹,仅在韧性断口或断口的韧性区出现宏观分层裂纹.研究表明,产生分层裂纹处的断口,分层裂纹无论是三角形分布或是其它形状分布,该区域均应评价为韧性.     

基于有限元方法的疲劳裂纹闭合行为

裂纹闭合行为将很大程度改变疲劳裂纹扩展行为。针对316L不锈钢,结合常幅加载和单个拉伸过载试验和动态数值模拟方法,对疲劳裂纹扩展行为中的裂纹闭合现象开展了一系列研究工作。详细对比了不同扩展阶段的裂纹闭合行为随裂纹长度、应力比和过载影响因素的变化,以及对裂纹扩展速率的影响。同时,研究了单个拉伸过载和裂纹闭合行为之间的内在联系和机理。结合裂纹闭合理论和有限元计算结果,等效应力强度因子被用来描述316L不锈钢的裂纹扩展过程,并提出316L不锈钢的裂纹扩展速率的预测模型。     

钢轨闪光焊接头轨腰水平裂纹的原因分析

通过金相显微镜和电镜检验了钢轨接头轨腰水平裂纹的宏观和微观形貌,发现裂纹源区存在大量呈韧窝形貌的木纹状区域,并且发现裂纹由钢轨-侧向焊缝扩展,裂纹尖端止裂于焊缝,裂纹表面存在脱碳的现象,证实了裂纹产生于焊接的高温阶段,属焊接热裂纹。     

硅砖中裂纹的成因及其分析

制品受到热冲击后内部会出现热应力，当热应力过大时制品中会产生裂纹。硅砖中裂纹包括表面裂纹和层裂。表面裂纹又分为横向裂纹、竖向裂纹和网状裂纹。通常层裂和竖向裂纹是机压所致，横向裂纹和网状裂纹是烧成造成的。影响裂纹生成的主要因素是烧成和机压，但与生产过程有关的其它因素的作用也不容忽视。     

多丝埋弧焊焊缝裂纹解析

裂纹是焊接中常见的一种缺陷。在多丝埋弧焊对接焊板试验中发现焊缝横向裂纹,通过对该裂纹的微观解析,发现裂纹断面上存在大量的"鱼眼"形貌,判断该裂纹是氢致裂纹。导致该裂纹产生的主要原因是焊缝内扩散氢与焊接残余应力的综合作用,在焊接时通过控制扩散氢的来源来防止氢致裂纹的产生。     

岩石裂纹扩展的力学分析

本文详细阐述和讨论了岩石裂纹分别在拉应力、剪应力作用以及拉剪应力共同作用下的扩展、闭合以及裂纹面上应力的传递问题。利用Barenblatt内聚力模型分析了裂纹顶端内聚力和裂纹面间摩擦力对裂纹扩展的阻尼作用, 讨论了在裂纹扩展过程中裂纹面间的接触条件、接触状态对裂纹扩展的影响。      

方坯和异型坯连铸技术的发展(二)

3.内部裂纹连铸方坯的内部裂纹可分为中间裂纹、中心裂纹、角裂纹和边裂纹四类。中心裂纹产生于铸坯断面的中心,它以距铸坯表面75～80mm 的位置为其外侧起点,穿过铸坯中心的柱状晶区,沿平行于铸坯的浇铸方向产生。中间裂纹多发生于铸坯的两个侧面,对应地分布于中心裂纹的两侧,其裂纹形态和中心裂纹极其相似。边裂纹多产生于距铸坯表面25～45mm 处,     

中厚板表面微裂纹成因及影响因素研究

对重钢连铸板坯轧制中厚板出现的表面微裂纹进行取样,经低倍检验发现,微裂纹有3种类型;与之对应的连铸板坯酸洗后发现,微裂纹也有3种类型,采用镀层结晶器铜板前以网状裂纹为主,尔后以横裂纹为主;对裂纹量最多的网状裂纹进行高倍和能谱检验,发现网状裂纹主要是铜裂纹.分析产生裂纹炉次的对应工艺,找出其主要影响因素是结晶器铜板、结晶器保护渣、二次冷却制度、钢中的w(N)等,针对性地采取预防措施,使中厚板表面微裂纹大幅度减少.     

钢板表面裂纹及氧化物圆点形成条件模拟试验

为了查明钢板表面裂纹产生的原因和产生机理,利用实验室加热炉对加热前和加热后产生的两种条件下的表面裂纹进行了模拟。试验结果表明,裂纹附近组织中脱碳层和氧化物圆点的出现是判断裂纹产生时间的必要条件,裂纹附近的脱碳层和氧化物圆点是轧制前坯料表面裂纹的基本特征,利用此特征查找裂纹产生的原因具有重要的指导意义。     

0.13C-5Mn中锰钢的裂纹扩展行为

 为了研究基体组织为铁素体和亚稳奥氏体的0.13C-5Mn中锰钢裂纹扩展特性,采用载荷控制对其进行裂纹扩展试验,采用SEM、EBSD等手段表征了裂纹扩展行为。研究结果表明,裂纹扩展机制为滑移和积累损伤双重机制。在裂纹尖端的塑性区内发生亚稳奥氏体转变为马氏体的相变,发生转变的区域远远小于裂纹尖端塑性区尺寸,由于相变吸收了能量以及裂纹闭合效应降低了疲劳裂纹扩展速率。     

Impact of Federal Environmental Requirements on Proposed Highway or Bridge Project

Prior to construction of a bridge or highway, the National Environmental Protection Act (NEPA) requires an evaluation of the effect of the project on the human environment. The purpose of NEPA is to require the head of the federal agency that is committing funds to the project to consider its actions before deciding to proceed with the project. This paper will analyze the general provisions of NEPA to remove some of the mystery related to the environmental concerns raised by bridge or highway projects and to emphasize to transportation planners that these concerns must be addressed prior to beginning a major bridge or highway project. The intent of this paper is to provide some guidance to transportation planners in light of these statutes as they begin the planning stages for highway and bridge projects.     

La relation père-enfant, la nature et l’organisation des relations d’attachement.

Faithfully following the tradition of Bowlby’s theoretical framework, until recently research in developmental psychology has more often confirmed the importance of attachment to mother than to father in their children’s development. Based on this statement, Paquette (2004) proposed a different theoretical model to account for the father’s specific role in children’s development. The purpose of this review of the literature is to examine results of studies including measures of attachment to mother and to father and to answer the questions raised by different theoretical models accounting for the organization of children’s attachment relationships, that is to say hierarchy in children’s attachment to mother and to father, correspondence between the quality of these two relationships and their influence on children’s development. Whether the attachment theoretical framework seems to partially account for the specificity and the complementarity of parental roles, results of the studies reviewed in this article underline the necessity to operationalize the activation dimension of attachment relationships (Paquette, 2004) in order to better understand how children’s attachment relationships to parents do develop and how they do organize themselves to influence children’s development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

固定式精炼炉的改进

江西铜业集团公司贵溪冶炼厂(简称贵冶)固定式精炼炉,因其在设计上存在缺陷及生产工艺的改变,不能满足生产的需要。在生产实践中积累经验后,将其进行技术改造。将改造前后的不同状况列出进行比较,从而阐述改造后取得的效果,最后列举出贵冶固定式精炼炉目前还存在的不合理因素,并设计出解决的方案,做到工作持续推进。     

Report of the Treasurer: 1980: Onward, financially and morally.

APA is in very good shape financially as a result of procedures and attitudes within the Council of Representatives and elsewhere in the Association's governance. We are able to maintain a balanced budget and to enjoy surpluses--though we can be certain that this will not continue forever--and at the same time to be reasonably solicitous of personal and social needs of the disadvantaged in our midst. At a time when the federal government finds it necessary to abandon or drastically cut programs to help the voiceless and other victims of our society, it is heartening to note that in our small way we psychologists are able to walk both sides of the street, that is, to help those who need our help, but to do so without imperiling our financial solvency. Despite spiraling inflation, the Association continues to produce a surplus from operations, as mandated by the Council of Representatives, while being responsive to the needs of the membership in a swiftly changing environment. In addition to the goal of building our reserves, we are dedicated to the continuation of all existing APA programs in our constant attempts to advance psychology as a science and profession and as a means of promoting human welfare. Financial statements for 1979-1981 are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling Residual Displacements of Concrete Bridge Columns under Earthquake Loads Using Fiber Elements

Nonlinear dynamic analysis with fiber-element models is now widely used to assess the seismic response of bridge structures. The ability of such models to accurately simulate response parameters for characterizing the postearthquake condition of bridges, namely residual displacements, is assessed by comparison of analyses of dynamically loaded reinforced concrete bridge columns to experimental data. The models are unable to capture residual displacements, and the cause of the inability to capture residual displacements is investigated through dynamic analysis of fiber-element and single-degree-of-freedom (SDOF) models. A certain type of pinching present in the numerical hysteretic response shape is found to lead to poor residual displacement simulation both in the SDOF models and in fiber-element models. When eliminating this pinching, improvements to residual displacement simulation are found. A modified concrete constitutive model representing damage accumulation from cyclic loading is implemented for the fiber-element analysis that incorporates changes to reloading behavior when moving from high tensile strain back to compression. Analysis using the modified concrete constitutive model leads to improvements in the ability of the fiber-element model to capture residual displacements.     

论我国会计委派制度试行中存在的问题及对策

会计委派制度有利于防止国有资产流失,保证会计信息的真实可靠性,强化会计核算和监督的力度,但在实施过程中存在委派会计人员不能充分发挥其职能作用,委派会计制度流于形式,委派会计人员的后续管理不完善等问题,必须加强对会计委派制度的重视程度,明确委派会计的任职条件和具体职责,建立委派人员的业绩考评制度和后续教育制度。     

Psychotherapy and Magic.

Discusses the extent to which the practice of psychotherapy places stress upon its practitioners similar to those experienced by the native fisherman of the Trobriand society, and the extent to which such stresses give rise to magical thinking. The observations in this article are based on a study of Trobriad society by Malinowski (in J. Needham's Science, Religion, and Reality). The author concludes that the ideal temperament for the psychotherapist if he is to behave rationally in his work involves the ability to reject the magic which the uncertainties of his task and the demands of his patients throw upon him; to be flexible enough to change his views when the need is clearly indicated, but not to be a weathervane; and to be happy enough in his personal, extratherapeutic life to accept failures as part of the day's work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rapid Bridge Replacement under Emergency Situation: Case Study

The terrorist attack on September 11, 2001, and subsequent potential threats to the United States transportation systems have presented an urgent need to elevate the security of the transportation infrastructure and to develop emergency response plans to quickly react to the possible consequences of an extreme event. Highway bridges, as critical components of the nation’s transportation network, have been brought to closer attention by government agencies. A research project was conducted to identify strategies and technologies to restore the use of a damaged bridge quickly. One of the tasks associated with the research was to perform several case studies of previous bridge replacements following extreme events. These events include explosion and fire caused by vehicle impact, vessel collision with a bridge, and damage caused by flood and earthquake. By studying the cases, the research team seeks to identify and expand on lessons learned and address which actions did and did not work well given the circumstances of the incident. These lessons have great value to the people who need to develop and implement an emergency response plan.     

ZD80减速器的设计

在ＺＤ８０减速器的设计中，对减速器箱盖采用了焊接结构，大齿轮采用组合结构；轴承采用刮油润滑方式，对于单向运转的减速器，装配型式可改为双端输入输出；在确定减速器配置方式时，应使承受最大作用力的轴承座上盖螺栓不承受拉力。