机械热脉冲焊接

本文介绍自制的机械热脉冲焊接设备的工作原理和焊接方法。由于进行这种焊接时,机械压力存在于焊接始终,温度控制十分灵活,因而这种焊接方法有它一些独到特点。将该设备用于微波集成电路外接微带形阻容元件及微带形晶体管的焊接已取得成功。利用械机热脉冲焊接方法,还能对金丝、铝丝作热压焊。实验表明该法可将金丝热压焊在蒸发的金、铜、铝等薄膜上;铝丝热压焊在金、铝等薄膜上。机械热脉冲焊接设备制作简单、操作方便、焊接可靠,适合于混合微波集成电路和薄膜电路使用。     

浅谈钢结构焊接质量控制

焊接是钢结构的主要连接方法,在建筑钢结构的建设中发挥了重要的作用.焊接质量直接影响整体建筑的质量.本文对高强钢焊接施工工艺、低温焊接施工工艺、厚钢板焊接技术、焊接变形原因及防治措施进行了分析.     

焊接技术与安全防护

焊接是钢结构的主要连接方法,在建筑钢结构的建设中发挥了重要的作用.文章分析了高强钢焊接、低温焊接和厚钢板焊接的施工工艺与安全防护措施.     

低碳钢焊接技术要点及缺陷分析

低碳钢含碳量低,锰、硅含量少在通常情况下不会因焊接而引起严重组织硬化或出现淬火组织.这种钢的塑性和冲击韧性优良,其焊接接头的塑性、韧性也极其良好.焊接时一般不需采取特殊的工艺措施,即可获得质量满意的焊接接头,故低碳钢钢具有优良的焊接性能,是所有钢材中焊接性能最好的钢种,在焊接生产上得到了广泛的应用.本文浅析硕士论文了低碳钢的焊接性和常见焊接缺陷,并针对各种焊接缺陷提出了预防措施.     

基于LTCC基板3D MCM TR组件的研究

X波段T/R组件3DMCMTR组件设计,建立了3DMCM模型库,LTCC基板的板间互联技术,通过国际主流的球焊技术了实现板间互联,并制作了板间垂直传输结构的样品,进一步缩小了组件尺寸。利用此技术针对一个X波段的TR组件给出了相应的设计。     

塑料超声波焊接的研究

随着焊接技术的发展,现今塑料焊接技术层出不穷,焊接方式多种多样.常见的各种焊接方式有超声波焊接、振动焊接、旋转焊接、感应焊接、热气焊接、挤出焊接、热板焊接以及接触电阻焊接等.其中,超声波焊接与振动焊接是在实际应用中最为广泛的.本文主要针对塑料超声波焊接工艺进行分析和探究.通过相关资料的学习以及文献的查阅,对这一工艺的原理以及具体过程进行研究.     

用钨极氩弧焊焊接不锈钢方面的新技能

钨极氩弧焊是现代工业制造中一种十分重要的焊接方式,本文分析了不锈钢薄板焊接熔池受力情况与该工件的焊接变形.详细介绍了钨极氩弧焊焊接不锈钢薄板时的焊接工艺要领和应用.     

基于生产导向的船体结构设计及运用

船体结构设计的优劣在很大程度上决定了船体焊接施工的效率和焊接质量.各种板材和骨材在焊接的过程中按照先报验、再焊接的工序来施工,但是当前这种施工方式效率非常低下.针对船体壁板、补板的焊接工艺改进方法进行研究,借助结构优化实现了壁板和补板一次性报验和焊接的目标,同时改进了肋板的施工方法.     

改进船舶焊接技术的对策

我国船舶行业经过近二十年大力推广应用高效焊接技术,特别是近年来船舶行业兴旺对焊接技术的需求,明显推进了船舶焊接技术进步.目前在船舶建造中应用的焊接工艺技术方法已经日趋成熟,焊接设备的成套化和高效化已取得明显进步,焊接机械化和半自动化平均程度已经达到65%以上,焊接生产效率和焊接质量稳步提高,焊接生产成本大幅度降低.     

无损探伤技术分析

压力容器焊接部位最容易产生焊裂、未熔合、未焊透、咬边、夹杂物和晶界开裂等缺陷,这些缺陷又可能是裂纹源.因此,正确地做好焊接缺陷等级评定工作不仅能保证产品质量,而且能保证产品的安全经济运行.但目前焊接缺陷等级评定情况去不尽人意,存在着这样那样的问题,焊接工艺中缺陷的名称与无损探伤中缺陷也没有统一.文章对无损探伤焊接技术进行了分析.     

Why and how do founding entrepreneurs bond with their ventures? Neural correlates of entrepreneurial and parental bonding

This paper investigates why and how founding entrepreneurs bond with their ventures. We develop and test theory about the nature of bonding in a functional magnetic resonance imaging (fMRI) study of 42 subjects (21 entrepreneurs and 21 parents). We find that entrepreneurs and parents show similar signs of affective bonding, that self-confidence plays a role in bonding style, and that the degree to which entrepreneurs include their ventures in the self and to which parents include their child in the self influences their ability to make critical assessments. Our findings suggest that bonding is similar for entrepreneurs and parents and that venture stimuli influence reward systems, self-regulatory functions, and mental factors that are associated with judgment.     

改善钢筋与混凝土黏结效果的措施研究

良好的黏结效果是钢筋混凝土构件正常工作的基础,本文从钢筋与混凝土黏结机理及影响因素入手,提出施工过程中改善黏结效果的措施,并以某框架结构为例,验证措施的可行性。     

W频段机场异物探测雷达收发前端

主要介绍了一种用于机场异物探测雷达的W频段调频连续波（FMCW）收发前端的研究工作。基于波导T形接头的等效计算公式,对W频段波导合成电路进行了集中参数的电路建模,通过优化设计波导合成电路的参数,提高了波导合成电路的容差特性,解决了W频段波导功率合成电路加工精度要求高的问题,实现了W频段4路功率合成;采用低损耗的石英基材设计开发了微带薄膜滤波器技术,实现了W频段FMCW雷达接收前端的一体化集成设计;通过对低噪声放大器芯片键和金丝的匹配设计,实现了W频段收发前端的低噪声接收。最终实现的W频段FMCW收发前端的发射功率优于360 mW,接收机噪声系数优于5 dB。研制的收发前端为W频段FMCW雷达提供了一种有效的射频前端的解决方案。     

Gold price risk and the returns on gold mutual funds

A model is presented for estimating the theoretical gold price elasticity of the value of mutual funds investing in gold mining companies. The theoretical elasticity shows that if the funds invest in companies whose assets are comprised primarily of operating gold mines, then the return of an investment in the fund will be at least as great as an investment in gold (i.e., the gold price elasticity of the gold fund is greater than 1). Empirical tests of the above propositions are presented. Empirical tests also show, however, that the gold mutual funds contain a substantial amount of risk which is not explained either by market risk or gold price risk. Accordingly, gold mutual funds and gold bullion do not bring identical risks to an investor's portfolio.     

Dealer spread and portfolio selection under price risks: evidence from the gold service industry

The bid and ask quotes as well as portfolio selection decisions of gold dealers who face a gold price risk are investigated within a continuous-time framework. The research integrates into a systematic analysis the decision of asset allocation in financial economics as well as the decision of a bid–ask spread in a market microstructure. The holding rate of gold is correlated to the intensity and jump size of the Poisson process, which is a hedging demand for gold assets against the risk of extreme events. According to empirical analysis from the gold service industries, the gold spread return is related to the expected return, volatility and jump risks of gold prices.     

甲霜灵试纸实地检测与色谱检测比对结果分析

本文介绍了甲霜灵胶体金免疫层析检测试纸实地应用的验证研究成果。甲霜灵胶体金免疫层析试纸设定的Cutoff值为0.5mg/kg,样品中农残含量低于Cutoff值时为阴性,试纸检测表现为两条红线;高于Cutoff值时为阳性,试纸检测表现为一条红线。用胶体金检测试纸检测表现为阴性的样品,经色谱检测结果均低于Cutoff值,阳性样品和添加Cutoff值样品经色谱检测结果与胶体金试纸检测结果一致,相关性良好。与色谱法相比较,胶体金免疫层析检测试纸检测蔬菜中农药残留具有操作简便、直观、快速、准确的特点,其特异性、敏感性高,适用性强,可作为蔬菜采摘前农药残留自我检测的手段。     

不锈钢盘条扭转性能差异与微观组织分析研究

对不同产地采用相同热轧工艺的不锈钢盘条进行了一系列的扭转试验,通过金相、扫描电镜等分析手段,探讨了不锈钢盘条扭转性能的差异原因与其微观织构的关系。     

Ethical Rule Breaking by Employees: A Test of Social Bonding Theory

As employees continue to lie, cheat, and steal from their employers, researchers have tried to help managers understand and possibly predict such deviant behavior. This study considers the specific employee misconduct of ethical rule breaking. Hirschi (1969) suggested that deviant behavior can be better understood by social bonding theory. The social bonding model includes four elements; attachment, commitment, involvement, and belief. It is proposed that Hirschi's social bonding theory can be used to understand ethical rule breaking by employees. Using a sample of 200 employees, the results indicate that the social bonding elements of attachment and involvement can be used to better understand the reported likelihood of ethical rule breaking of employees. Recommendations for better applying the social bonding model to ethical rule breaking are suggested.     

高职院校物流专业校内实训管理机制探讨

校内实训作为高职院校的重要组成部分,其管理机制直接影响到人才的培养。如何使高职院校实训管理规范化、制度化,是高职院校一直在探讨的问题。本文基于"6S管理"思想提出"大球带小球"模型,来解决高职院校物流管理专业校内实训管理的问题。     

一种低损耗毫米波垂直互联设计

设计了一种利用球栅阵列(BGA)的毫米波垂直互联,解决了毫米波系统三维（3D）集成时层间信号互联的低损耗传输问题。根据传输线理论,利用电磁仿真软件对这种采用BGA的垂直互联进行了仿真,并对层间通孔半径、焊球半径、焊盘半径等对传输性能的影响进行了分析。样件测试结果显示,在28.4~30.4 GHz,其层间垂直传输损耗小于0.36 dB,反射小于-15 dB。该垂直互联结构简单、性能良好,可广泛用于毫米波微系统3D集成。