美国几种不需垫铁的通用可调压板

当前国内机械厂使用的压板大都是带垫铁的,用垫铁来调整高度,使用和保管很不方便,常常需要准备许多块大小、厚薄不同的垫铁,浪费了许多辅助时间。 本文介绍几种美国机械公司从80年代开始使用的不需要垫铁又能随意调整高度的通用可调压板。     

高方平筛压紧机构分析

通对筛格垂直方向压紧的机构分析,面粉厂家使用现状简单介绍,随动压紧装置结构,提出使用的合理建议。     

折叠式水桶

<正>产品概述该产品采用进口牛筋布料,可折叠。使用时拉开即可,使用完毕后,沿顺时针方向旋转压紧合并,放下提手便可还原。     

上纵臂托架左右件成型模具设计应用

<正>一、引言如下图1所示为某车型上纵臂托架工件图,材料为SAPH400,厚度为4.0mm,该工件的特点是尺寸精度要求较高;成型高度85.5mm,改进前采用的是下料三块板,成型后进行焊接,由于下料时有偏差,手工成型不到位,焊接后工件变形过大,质量达不到图纸要求,生产效率过低。     

新式CNC万能铣床

在德国海姆莱(Hermle)公司最新推出的CNC万能铣床上,采用了名义立式主轴沿X、Y轴移动而工作台只作Z轴移动的新方法。 这种配置不但保证了工件加工尺寸与恒定加工高度的联系,而且确保了X、Y轴刀具行程与工件动态参数的独立性,使理想的工件动态参数为高速移动,且进给率可高达20m/min。     

超声波斜探头磨损对超声探伤的影响与修复方法

在超声无损检测中,斜探头在使用过程中与检测工件产生摩擦,根据个人习惯、所检测工件及使用频率的不同探头会产生不同程度的磨损,探头经过磨损后其原有的特性会遭到破坏。本文就是讨论这种破坏对检测工作的影响及如何通过修复探头来纠正这种影响。     

继电保护压板微机化实时监控

在电力系统实际运行中,因继电保护压板投退不当,造成保护系统无法完成跳、合闸动作的现象时有发生,甚至造成故障扩大,严重影响电网的安全稳定运行。如果能够对继电保护压板进行实时监控,则完全可以避免此类事故的发生。     

重介立轮洗选机密封气囊压板安装技术改造

本文结合唐山开滦吕家坨矿业分公司重介立轮洗选机更换过程中,对密封气囊压板的安装进行讨论,针对安装过程中的实际难题在现场分析并解决,总结出安装重介立轮洗选机密封气囊压板的新方法.     

浅谈手工电弧焊基本原理和安全特点

手工电孤焊是利用焊条与工件间产生的电弧热将焊条和工件加热熔化而进行的焊接.这种焊接方法可在室内、野外、高空等各种场合下进行.它的设备简单,容易维护,焊钳小,使用灵活,广泛适应于各种黑色金属和有色金属的焊接.     

浅谈拉刀的合理使用

从工件的工艺要求、拉刀使用前校验与试拉、拉刀的操作规程、拉削速度和切削液的选择等方面介绍了合理使用拉刀的经验和应注意的一些问题。     

洗选煤渣浆泵叶轮表面加工质量的探讨

在洗选煤渣浆泵叶轮的加工过程中,有很多复杂的卤素影响其表面质量。文章从金相组织的变化、热塑性变形、冷塑性变形以及工件在磨削时产生的裂纹等问题进行探讨和分析。     

退休老年人身体形态与力量素质相关关系的研究

近年来老年人的身体健康现状日益成为人们关注的焦点问题之一,为了对退休老年人的身体健康状况有进一步的了解,对58-68年龄段退休老年人进行身体形态和力量素质的测试。研究发现身高与握力（r=0.659）、体重和握力（r=0.655）均有显著相关性,且呈正相关趋势,身高与体重（r=-0.243）呈负相关。因此在适度原则下,应加强以力量素质为主的体育锻炼,其对于提高身体素质,增进健康有非常重要的意义。     

Auction Fever! How Time Pressure and Social Competition Affect Bidders’ Arousal and Bids in Retail Auctions

Auction sites on the Internet frequently put bidders under time pressure or highlight the social competition that is inherent to auctions. Both aspects are believed to elicit an exciting shopping experience, which may culminate in auction fever. In two laboratory experiments, we investigate the process of auction fever in retail auctions and demonstrate when and how auction fever affects bidding behavior. In contrast to previous studies, we employ physiological measurements as an objective and continuous assessment of bidders’ arousal in addition to a subjective assessment of bidders’ emotions through psychometric scales. Moreover, we explicitly study the interaction of time pressure and social competition on arousal and bids. We find that bidders’ arousal is increased in high time pressure auctions and that this leads to higher bids in ascending auctions—but only when bidders compete with human opponents. Thus, social competition is the actual driver underlying the auction fever phenomenon. Furthermore, we show that the “joy of winning” is significantly stronger than the “frustration of losing” in ascending auctions. Finally, we discuss the implications of our findings for the design of retail auctions.     

Why Do Firms Enter into a New Niche Market? An Integrated View of Objective and Subjective Antecedents of Strategic Decisions

This study is based on behavioral theories and has the purpose of determining the predictors and contingencies of strategic decision making within the strategic tripod framework and CEO age effect. Furthermore, we focus on the effect of the interaction of these aspects on strategic decisions. Multiple theories and concepts are applied in this paper, such as the institution-, industry-, and resource-based view, upper echelons theory, socio-emotional wealth, empathy, and so on. Specifically, we focus on why Chinese real estate firms decide to enter the aged housing market. By conducting an empirical study using panel data from 134 listed Chinese real estate companies, we make the following conclusions: Institutional pressure and competitor numbers positively affect, whereas slack harms, the likelihood of entry. Ceteris paribus, the resource effect is strongest when the institutional effect is the most significant. When facing institutional pressure, a firm with a CEO older than 50 is significantly more likely to enter the aged housing market than firms with a CEO that is younger.Relieving institutional pressure and avoiding cutthroat competition are helpful in making strategic decisions but not for digesting slack resources. The CEO makes strategic decisions by replying to institutional pressure but likely not from engagements in resource or competitive affairs.     

目标高度对广域多点定位系统精度的影响

广域多点定位技术是对航路和终端区域的飞行器进行监视的新技术,由于多个接收站 点通常布局在地面上,站点的基线长度和飞行器高度对系统的定位精度至关重要。根据双曲 线/面定位技术,导出了最小二乘法解算目标位置时定位精度与高度误差的关系,然后对同高 度层和高度层变化的水平精度稀释和垂直精度稀释进行了分析和仿真,证明了高度变化对精 度影响显著的结论。最后,讨论了站点布局的作用,在高度不变的情况下,适合的布站形状和 基线长度可减小高度误差对定位精度的影响。     

卖空压力抑制经理人私有收益吗？——基于中国放松卖空管制的准自然实验

针对放松卖空管制能否抑制经理人私利问题,本文借助我国融资融券制度逐步推行提供的准自然实验机会,采取双重差分法研究了卖空压力对公司经理人私有收益的影响。研究发现,卖空压力显著抑制了经理人的私有收益,在进行了多项稳健性检验之后,该结论依旧成立。进一步的研究中我们还发现,卖空压力对经理人私有收益的抑制作用在信息透明度高、经理人权力较大、行业竞争激烈的公司中表现得更为明显。本文研究结论表明,作为一种外部治理机制,融资融券业务带来的卖空压力缓解了公司内部的委托代理问题。     

控股股东股权质押压力与企业创新粉饰

控股股东股权质押已经成为资本市场的重要现象，如何全面理解股权质押是学术界的焦点。区别于以往研究仅关注质押数量，文章基于手工整理的初始质押股票价格，度量股权质押压力，研究其对创新“粉饰”的影响。以2008—2018年A股上市公司为样本，本文研究发现，股权质押压力越大，企业通过创新粉饰提升股价的现象越严重；在平仓风险更高、企业经营压力越大时，股权质押压力对创新粉饰的影响更强。文章从一个全新的视角分析股权质押的重要影响，为纾解股权质押风险、推动创新强国建设提供政策依据。     

Resistance to Change in the Corporate Elite: Female Directors’ Appointments onto Nordic Boards

In this empirical study, we investigate the variation in firms’ response to institutional pressure for gender-balanced boards, focusing specifically on the preservation of prevailing practices of director selection and its impact on the representation of women on the board of directors. Using 8 years of data from publicly listed Nordic corporations, we show societal pressure to be one of the determinants of female directorship. Moreover, in some corporations, the director selection process may work to maintain “a traditional type of board”. In such boards, demographic diversity among male members appears to be associated with a lower share of female directors, although we cannot establish wether this reflects discrimination or a desire to maintain critical competencies. With this paper we add to the theoretical understanding of the factors underlying female board appointments by adopting an institutional theory lens to study female board representation. Viewing the demands for gender-balanced boards in terms of societal pressure for the de-institutionalization of the prevailing norms and practices, we highlight preferences for maintaining established practices as a potentially important barrier to institutional change. On these grounds, we conjecture on the relationship between the gender diversity of boards and other diversity dimensions. We suggest that a board room gender quota (if implemented) is supplemented by policies to ensure the transparency of board changes, in order to prevent the crowding out of other diversity dimensions.     

Height, fun and safety in the design of children's playground equipment

The study reported in this paper adopted a holistic design approach to investigate issues associated with height related playground injuries from a users' perspective. The main objective was to gain an understanding of the relationship between height and fun so as to establish practical guidelines for addressing the causes of height related injuries whilst maintaining the attributes of playground equipment that children find fun and challenging. Results show that, on the one hand, the risk of injury increases when height is coupled with the use of upper body strength and, on the other hand, that coordination is a greater source of fun and challenge than height for children. Accordingly, it is suggested that the level of risk of injury attached to children's playground equipment can be reduced when the use of lower body strength and coordination are combined with lower free fall heights.     

空、实仓压力半衰期关系的探讨

通过对影响半衰期的各个因素的分析,提出空、实仓半衰期的数学关系。已知空仓半衰期、粮食品种通过表格或曲线可以查出某装粮高度的理论实仓半衰期。通过修正系数修正就可以得出近似实仓半衰期。