路面冷铣刨机履带行走机构设计参数分析

在分析路面冷铣刨机履带行走机构工作原理的基础上,提出了履带行走机构牵引力及输入功率的计算公式,并给出了驱动链轮、支重轮及导向轮的设计原则.     

大跨度桥梁结构有限元抗震分析的多点输入法

本文考虑地震动场的空间相关性 ,对大跨度桥梁结构在多点输入地震作用模式下的抗震分析方法进行了研究。该法由响应量幅值的平方直接求得特定频率点 ,该响应量的功率谱值 ,进而可求得其均方值等统计特性 ,与传统的均匀输入法相比 ,增加的工作量不多但更符合工程实际     

LY12铝合金搅拌摩擦焊工艺研究

对LY12铝合金进行了搅拌摩擦焊接工艺试验,并对焊接接头进行了金相观察和力学性能检测.试验结果表明,合理的焊接参数匹配是取得性能优良焊接接头的前提.当旋转速度为905 r/min、焊接速度为33.6 mm/min、肩部压力为48 MPa时施焊,可获得成型良好无缺陷焊接接头,且焊缝区晶粒细小.搅拌摩擦焊焊接轧态LY12铝合金时,焊接时的热输入可部分消除接头处金属的冷作硬化.随着焊接速度的提高,焊接热输入量降低,消除冷作硬化的能力减弱,焊接接头抗拉强度提高.     

论农村公路建设与养护

针对目前我国农村公路建设与养护的现状和存在的问题,指出农村公路建设和养护管理的意义,主要从建立建设和养护管理制度、加强建设和养护工作的资金管理两个方面提出了提高农村公路建设和养护管理水平的措施。     

基于分布式压电片的圆柱壳结构振动功率流主动控制研究

对基于压电片作用的圆柱壳结构振动功率流主动控制进行了研究,原始激励假设为周向余弦分布线力形式,使用压电片作为控制激振器。以输入壳体的总功率流为控制目标函数,利用导纳函数将其表示成外加电压的二次型函数形式求解最优控制电压。通过计算分析发现,压电片与原始激励间的轴向距离及压电片周向粘贴位置,都会对控制后输入壳体的总功率流产生较大影响,且影响形式不同。     

社会资本及其获取途径

本文对国外学者有关社会资本的定义进行了学理上的辨析,提出了自己对社会资本的定义。在理论分析的基础上,结合中国社会的实际情况,将中国社会行动者的社会资本划分为“基础性社会资本”和“自获性社会资本”两种类型,并分别论述了两种社会资本的获取途径及其对社会行动者的意义,从个人生命历程的视角对中国社会行动者社会资本的获取作了一个较为完整的诠释。     

The place of transport in facilitating social inclusion via the mediating influence of social capital

Social policy makers rarely associate the ability to be mobile with having a role in the facilitation of social inclusion. This paper provides an initial exploration of the association between a person’s travel patterns and their risk of social exclusion. Information is drawn from a major Australian Research Council transport study which interviewed 535 people from Metropolitan Melbourne, Australia. It includes an analysis of the extent of the person’s bonding and bridging social networks, their connectedness to the community, self-assessed level of well-being and their beliefs about whether or not they are able to control outcomes in their life. It was found that those who had the greatest risk of social exclusion, travelled less often and less distance, owned fewer cars and used public transport less, than those who were more socially included. However, those who were more at risk of social exclusion did not identify their lower trips as due to either a lack of transport, or problems with the public transport system. The ability to have good bridging networks appears to be related to increased trip-making and promotion of social inclusion but not necessarily self-assessed well-being which is satisfied by bonding networks.     

简码扩充输入法原理及其应用

计算机处理的文本中重复出现的词组定义为简码，这有利于减少输入工作量，但一种编码法已定义了一定量的简码汉字，在一个编译系统里就无法再重定义。现考虑了一种ＷＰＳ与原有汉字输入法不矛盾的简码扩充输入法，可实时以简码形式定义词组，并有相应的译码软件翻译成汉字，方便了使用。     

Incentive Contracts for Venture Capital Syndication

IntroductionThe uncertainty in venture capital market and in-formation asymmetry during venture capital investingprocess make syndication in the second and later sta-ges a hot issue.The syndication is important for re-ducing the risk effectively,increasin…     

Empirical analysis of transportation investment and economic development at state, county and municipality levels

Numerous studies have found positive correlation between transportation infrastructure investment and economic development. Basically these studies use a conventional production function model augmented by a public capital input, mainly highways, rail and other transportation facilities. While the range of the measured economic growth effects varies widely among studies, the positive elasticity between transportation investment and economic development is now commonly accepted. Still a major puzzling issue is that the magnitude of the measured effect seems to decline significantly as the econometric model is further refined, mainly with regard to space and time lags. That is, the use of national or state data produces elasticity results, which are much larger than when using county or municipality data. Similarly, when we introduce into the econometric model a lag between the times when the transportation investments are made and when the economic benefits transpire, the measured elasticities decline with the size of the lag. Thus, the main objective of this paper is to investigate these issues analytically and empirically and provide a plausible explanation. We do so by using alternative econometric models, applying them to a database, which is composed of longitudinal state, county and municipality observations from 1990 to 2000. The key result is that transportation investments produce strong spillover effects relative to space and time. Unless these factors are properly accounted for many reported empirical results are likely to be overly biased, with important policy implications.