合金化对Ni3Al性能的影响研究

文章介绍了Ni3Al的力学性能,综述了不同合金元素对Ni3Al的力学性能的宏观影响,并大体从微观结构上分析了合金元素对其性能影响的原因.     

Si含量对5056铝合金显微组织与性能的影响

将不同含量的Si(从1%到9%)加入5056铝合金中,再将同等含量的分成两组,其中一组经过固溶加时效处理。分别对各组试样进行金相显微组织观察和布氏硬度测试,探究Al-Mg-Si合金中不同Si元素含量对组织和合金力学性能的影响,以及热处理对同含量试样组织和力学性能的影响。试验结果表明:随着Si元素含量的增加,合金力学性能呈单调上升趋势。     

钨基高密度合金热处理力学性能的研究

钨基高密度合金因具有高密度和优异的力学性能而得到了广泛的应用。本文采用扫描电镜、室温拉伸和室温冲击等手段，系统地研究了热处理对钨基高密度合金力学性能的影响。钨基高密度合金热处理实验证实，真空退火、固溶淬火对钨基高密度合金力学性能有显著的影响。真空退火能有效地提高合金的力学性能，这是由于真空退火能减少氢气烧结态合金中的氢脆，并且使镍和铁在钨中的扩散层增厚，界面结合力提高，从而提高了界面结合强度，合金力学性能显著提高。     

合金元素对3104铝合金组织和力学性能的影响

文章研究了合金元素对3104铝合金组织和力学性能的影响。3104铝合金中包含MnAl6相、(FeMn) Al6相和Mg2Si相等。随着Mg含量的增加,合金的塑性降低。随着Mn含量的增加,合金强化作用明显,但塑性亦随之降低。Fe/Si比值对合金强度和塑性洋浦显著影响,不能忽视。     

Al-Ti-C-Sr中间合金对车轮铸造用A356合金细化与变质双重作用的效果研究

用Al-Ti-C-Sr中间合金对车轮铸造用A356合金进行细化、变质处理,熔体处理温度740°C,浇注试样。对试样显微组织分析,Al-Ti-C-Sr中间合金对A356合金具有细化与变质双重作用;对试样进行力学性能分析,Al-Ti-C-Sr中间合金对A356合金有较强的细化、变质能力。     

钨基高密度合金烧结力学性能的研究

钨基高密度合金因具有高密度和优异的力学性能而得到了广泛的应用。本文采用扫描电镜、室温拉伸和室温冲击等手段，系统地研究了烧结方式对钨基高密度合金力学性能的影响。试验结果表明，氢气烧结态合金的抗拉强度随着W含量由90％增加到95％时有所提高，而当W含量进一步提高时，合金的抗拉强度略有降低。伸长率和冲击韧性随着W含量由90％增至97％时逐步减小。真空烧结不仅能避免氢气烧结时所引起的氢脆现象，而且可以改善液相对固相的润湿性，因此真空烧结态合金的力学性能高于氢气烧结态合金。     

1Cr17Ni2钢稳定化回火工艺研究

文章紧跟工程实际,以航空领域常用的1Cr17Ni2不锈钢为研究对象,重点研究1Cr11Ni2不锈钢在660℃、650℃、640℃温度环境下稳定化回火处理后的力学性能变化,尤其是硬度的变化,同时研究了1Cr17Ni2不锈钢在亚温淬火、多次回火时的力学性能,为零件承制单位解决了实际生产中遇到的问题.研究结果表明:对于1Cr...     

羟基镍粉对AB_5型储氢合金电化学性能的影响

本文采用真空感应电弧炉熔炼制备了AB5型储氢合金,经机械研磨后与Ni粉充分混合,通过三电极体系测定了储氢合金电极Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3/Ni的电化学性能。试验结果表明,羟基镍粉的添加极大的提高了储氢合金的电化学性能。与未添加Ni粉的合金电极相比,所有Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3+Xωt%Ni(x=0～300)电极经2次充放电循环后均完全活化,且其最大放电容量随着羟基镍粉含量的增加而增大。此外,在大电流放电试验中,添加Ni粉的合金电极显现出良好的高倍率放电性能。其中,当x=200时,合金电极仅经过1次充放电循环即可活化;其最大放电容量可达314mAh/g;高倍率放电能力HRD300为81.2%。     

稀土-镁系储氢合金的相结构与电化学性能研究

La3(Ni0.80Co0.15Al0.05)9合金经过熔炼后按La3(Nio0.08Co0.15Al0.06)9+Mg-x wt.%(x=10～40)与镁粉混合,混合粉末压片并在800℃下烧结5小时,研究结果表明,合金的主相包括La2Ni7相和CaCu5-型结构的La[Al,Ni)5相,有少量的Mg17La2、La(Al,Co)5和MgNi2相;电化学测试结果表明,合金易活化,Mg含量的增加使台金电极的放电容量下降,但是能够提高合金电极的充放电电压.     

哈氏合金C276应用及焊接性能研究

电站设备在腐蚀环境下性能及寿命均受到较大影响,增强耐蚀性成为一大技术难关。哈氏合金C276为美国合金牌号,具有良好的力学性能和耐腐蚀性能,但其焊接性能较差。文章系统介绍了哈氏合金在电站设备抗腐蚀方面的应用以及该合金的化学成分、力学性能、焊接工艺特点、焊材选择等,供工程技术人员参考。     

Limits of predictability in forecasting in the behavioral sciences

A series of methodological problems in forecasting which arise out of the humanness of the predictor and/or predictee are reviewed. These include (1) perceptual disordering, in which the imperfect nature of data collected by human sensation is investigated, (2) model disordering, in which the imperfect nature of models and theories arising out of human information processing limitations is investigated, and lastly, (3) obtrusive reactive disordering, in which the human tendencies of the predictee, to guess the forecast, and to alter his or her behavior so as to reinforce or interfere with the forecast, are explored. The implications of these methodological dilemmas for forecasting are discussed.     

Planned Global Interdependence as a Foreign Policy Goal: The Problem of Coordinating Trading Relationships

A bstract . The significance of the concept of interdependence is dealt with from four aspects. 1) Attention is focused upon the meanings attached to the concept of interdependence in the growing literature on the subject. 2) The mathematical structure of the concept is analyzed and its implications for, and restraints upon, global planning are emphasized. 3) the analysis of the implications of the concept for global planning is further extended by a discussion of the tasks that would be involved in all efforts to coordinate global plans that have been developed within a framework of International forms of interdependence. 4) An effort is made to relate the tasks of coordination for global plans that reflect various forms of interdependence, to economic concerns and to the relationships that arise for interdependencies of trade.     

Business ethics: the materiel/manufacturing perspective

The discussion of purchasing practices and product integrity, which have ethical implications for materiel/manufacturing management, serves to illustrate how routine decisions can have larger implications for the firm as a whole. Management needs to take a proactive role in confronting ethical issues by (1) demonstrating a corporate commitment to sound ethics in business practices, (2) providing written policies where appropriate to provide a basis for sound ethical conducts, (3) educating various functional areas to understand their responsibility in seeming unrelated ethical problems, (4) delegating authority in ethical issues where such issues are considered in decision making, and (5) fostering interfunctional communication as a means in establishing corporatewide responsibility. The basic philosophical principles of JIT serve as a blueprint for recognizing and managing ethical responsibility. The unexpected by-products of a JIT implementation may be vendor/customer good will and an excellent reputation for the firm.     

Welcome to the bright side: Why,how, and when overqualification enhances performance

We nuance the overtly negative image of overqualified employees by illuminating the brighter side of overqualification. In this extension of current thinking on overqualification, we argue that there are four ways in which overqualification can positively shape the performance of overqualified employees and their fellow group members. Following their theoretical basis, we refer to these as the (1) human capital, (2) status, (3) social learning, and (4) identification advantages. For each advantage we explain the conditions under which they are likely to materialize. We also theoretically explore how the advantages relate to each other as well as to the theories outlining the potential negative consequences of overqualification, and provide an according integrative model on the Relational Effects of Overqualification on Performance (REOP). After discussing the theoretical implications and providing an agenda for future research, we close with a discussion of the managerial implications of leveraging the bright side while acknowledging the dark side of overqualification.     

意义的类型与英语词汇教学探讨

文章首先通过实例对英国语言学家利奇提出的词汇意义的类型做了简要的论述,然后在此基础上提出了对英语词汇教学的启示:一、重视概念意义有细微差别的词汇教学。二、注重概念意义相对立,但指称范围、表达的程度和隐含的褒贬等方面有差异的词的教学。三、英语词汇的教学应重视词汇的社会文化因素。     

Entitlements to continued life and the evaluation of population health

Review of Economic Design - We analyze the implications of axioms formalizing entitlements to continued life for the evaluation of population health, when combined with basic structural axioms. A...     

Reliable entertainment: Spanish consumers' preferences regarding a film's country of origin

• This article contributes to the study of cinema audiences in Europe by analyzing the actual behavior of Spanish moviegoers and their level of satisfaction. We modeled moviegoers' choice of film by country of origin (U.S.A., Spain, and other countries) according to a set of determinants: (1) consumers' interpretation of several sources of information, (2) motivations and (3) choice rules. We found three clear consumer stereotypes related to each type of film: (1) U.S.A. films were preferred by almost everyone (especially families and younger audiences); (2) Spanish films had audiences composed of middle-age and middle-class moviegoers; and (3) European productions were preferred by a social or intellectual elite. U.S.A. films dominate the Spanish market for the reason that they provide most of what moviegoers prefer, namely, familiar, reliable entertainment in Spanish; three characteristics that are not satisfied by Spanish and European films. Additionally, we discuss the implications for the European cultural policy.

Copyright © 2007 John Wiley & Sons, Ltd.     

Economic multipliers for the Maltese Economy

The aim of this paper is to build an econometric model for the Maltese Economy and to use this model in deriving economic multipliers which may prove useful for future economic planning, particularly since Malta must find substitutes for the income derived from the Military base after 1979, the year of independence. Both the methodology and the results of this paper should be of general use to small developing economies with limited domestic resources. In Section 1 we provide an outline of the theoretical foundation of the model. This is intended to serve as a guide for noneconometricians. Section 2 considers the functional relationships between relevant economic factors. These relationships are used in Section 3 to estimate the economic multipliers. Finally in Section 4, we examine the main policy implications of the model for economic planning.     

A Syllogism for the Small Farm

A bstract . Access to the land for low-income households has long been considered a contributing factor to political stability. The reasoning behind this hypothesis can be given the form of a deductive argument whose premises assert implications that link greater real income with greater well-being for the poor ; greater well-being with greater political acquiescence of the poor; greater real income of the poor with a greater downward redistribution of wealth ; and greater political acquiescence with greater governability of the poor. The kinds of productive activities which will satisfy these implications are those involved in subsistence farming. From the premises the conclusion follows that greater governability of the poor is a consequence of the greater downward redistribution of wealth that accompanies subsistence farming.