三线铁路荷载作用下箱梁桥荷载横向分布系数

文章运用有限元程序对三线铁路预应力混凝土连续箱梁桥进行了模拟,分析了三线铁路荷载作用下箱梁的受力特性及在各种荷载工况下荷载横向分布规律,给出了荷载横向系数的实用值。     

Motives in the Acquisitions of NASDAQ Targets during the Aftermath of the 1987 Crash

After the crash of 1987, the Nasdaq composite index stayed below the precrash level for nearly two years. Takeover activity surged in this after‐crash period. We compare the motives in the acquisitions of Nasdaq targets during the after‐crash period with those in the ten‐year period before the crash. We find that the announcement period return to acquirers and the proportion of acquirers with positive gains declines in the after‐crash period. For both the periods, agency is the motive for takeovers that have negative total gains (acquirer + target), but synergy and hubris are comotives for takeovers that have positive total gains. The proportion of takeovers in which the managers of acquirers act against the interest of the shareholders increases after the crash.     

“入世”对石家庄市优质农产品及加工业的影响程度分析

本文以第一手的资料详细阐述了在石家庄市农产品的现状,分析了我国加入WTO将对石家庄市农产品产生的影响（机遇与挑战）,并提出一些改进建议。     

锈蚀钢筋混凝土薄壁箱梁非线形分析

薄壁箱梁结构由于其结构轻,刚度大,在结构工程中得到了广泛的应用.钢筋锈蚀是影响混凝土结构耐久性的重要因素,为了正确评估钢筋锈蚀后构件的裂缝发展情况,本文利用大型有限元软件ANSYS通过对锈蚀钢筋混凝土薄壁箱梁的非线性分析,得到了锈蚀构件的裂缝的变化规律.     

Post encroachment time threshold identification for right-turn related crashes at unsignalized intersections on intercity highways under mixed traffic

Abstract

Unsignalized intersections in developing countries experience many serious conflicts between cross-traffic due to indiscipline traffic manoeuvrability. Historically, Post Encroachment Time (PET) has gained attention as a proximal indicator to analyze crossing conflicts. However, identifying an appropriate PET threshold to classify critical conflicts for highly heterogeneous traffic scenario is still an unexplored area. Consequently, this study proposes a novel approach of PET threshold identification with proof of application by collecting data from ten intersections located on four-lane intercity highways in the National Capital Region (NCR), India. Both crossing conflicts and right-turn related crash data (for the left-hand drive) are collected. Their correlations are thoroughly studied for each PET threshold using a quantitative technique considering all and individual vehicle categories. Finally, a qualitative analysis is done by ranking the sites based on cumulative PET and related crashes to verify the proposed quantitative technique. A PET threshold of 1?s is obtained from both the techniques which can be used to identify critical conflicts for unsignalized intersections located on four-lane intercity highways. The proposed methodology will serve as an alternative, faster and effective tool to evaluate the hazardousness of unsignalized intersections located on intercity highways under highly heterogeneous traffic condition.     

The Crash of 1882 and the Bailout of the Paris Bourse

The crash of the French stock market in 1882 presented the Paris Bourse with its worst crisis of the nineteenth century. Its structure was similar in key respects to today’s futures markets, with a dominant forward market leading the Bourse to adopt a common fund to guarantee transactions and liquidity. While this mutualization of risk protects clients and brokers from idiosyncratic shocks, it is generally assumed that it also provides considerable protection against systemic shocks, as no twentieth century exchange has been forced to shut down. Using new archival data, this paper shows how a stock market crash overwhelmed the Bourse’s common fund. Only an emergency loan from the Bank of France, intermediated by the largest banks, prevented a closure of the Bourse.

面压试验在全金属气缸垫泄漏故障解决中的应用

文章简述了全金属气缸垫面压分布原理和面压试验的操作流程,利用气缸垫泄漏故障分析导致气缸垫泄漏的潜在原因并按照拆机顺序逐一排查,针对背离项提出改进措施,经过试验验证了解决措施的有效性。在解决问题的过程中,面压试验的应用起到了关键作用,这对面压试验在解决发动机气缸垫泄漏故障中的应用具有很好的指导意义。     

公路30m箱梁预制施工方法探讨

文章以广西河池市金城江五桥项目为例,通过改变箱梁内模结构,并采取相应砼浇筑顺序,从根本上解决了箱梁底板砼浇筑质量难以保证的问题,供其他类型梁体预制参考与借鉴。     

现浇混凝土箱梁施工质量控制

本文对现浇混凝土箱梁施工的关键技术进行了分析与探讨,以使施工质量得到有效的控制。     

箱体数控铣削加工变形原因分析及控制对策研究

本文对箱体类零件的结构特点进行了简要分析,阐述了箱体类零件加工的重要性,对箱体类零件加工变形的原因进行分析总结,并提出了控制箱体类零件加工变形的对策,对生产实际有较强的指导作用。