小直径薄壁管直接拉伸方法研究

大学材料性能实验教学通常以棒料单向拉伸为主要内容,而未能兼顾各种型材在服役状态下的几何属性对材料属性的影响。研究小直径薄壁管直接拉伸实验技术和方法,并将其引入实验教学,使学生通过实验自主地分析塞头装配、试样类型及加载速率对拉伸结果的影响,取得了良好的实践教学效果,对管形状态下材料力学性能的准确获取与促进管材塑性成形理论研究具有重要学术意义。     

随形就势的留园之廊

廊是园林中常见的建筑物,是具有明晰的几何关系的线型空间。留园中的廊,不论从它所传达出的文化内涵和意境来看,还是从它所体现的设计过程和手法来看,都具有极好的研究价值。通过对留园廊的研究,不仅能更好地感悟留园的布局、建筑空间等,还能对苏州古典园林中廊的设计特点和艺术效果获得更多、更好的了解。     

Dynamic analysis of a high-speed train operating on a curved track with failed fasteners

A high-speed train-track coupling dynamic model is used to investigate the dynamic behavior of a high-speed train operating on a curved track with failed fasteners. The model considers a high-speed train consisting of eight vehicles coupled with a ballasted track. The vehicle is modeled as a multi-body system, and the rail is modeled with a Timoshenko beam resting on the discrete sleepers. The vehicle model considers the effect of the end connections of the neighboring vehicles on the dynamic behavior. The track model takes into account the lateral, vertical, and torsional deformations of the rails and the effect of the discrete sleeper support on the coupling dynamics of the vehicles and the track. The sleepers are assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. The train model couples with the track model by using a Hertzian contact model for the wheel/rail normal force calculation, and the nonlinear creep theory by Shen et al. (1984) is used for wheel/rail tangent force calculation. In the analysis, a curved track of 7000-m radius with failed fasteners is selected, and the effects of train operational speed and the number of failed fasteners on the dynamic behaviors of the train and the track are investigated in detail. Furthermore, the wheel/rail forces and derailment coefficient and the wheelset loading reduction are analyzed when the high-speed train passes over the curved track with the different number of continuously failed fasteners at different operational speeds. Through the detailed numerical analysis, it is found that the high-speed train can operate normally on the curved track of 7000-m radius at the speeds of 200 km/h to 350 km/h.     

皮带煤仓转载工程施工体会

本文介绍了开滦钱家营矿业分公司八采区皮带煤仓转载工程的卸载硐室、煤仓、给煤机硐室的施工工艺,采用合理、先进的施工方案,实现了安全、优质、高效。     

Java的多线程动画技术

讨论了网络教学软件中原始图像的加载问题,给出了一种高效正确的多线程解决方案和其例程片断。     

游戏引入策略在C语言算法教学中的应用

C语言程序设计是一门理论性和实践性都很强的课程,针对高职院校中C语言初学者普遍反映难学的状况,本文在J.Sweller的认知负荷理论的指导下,从学生的认知心理规律出发,依托典型的递归算法案例分析了游戏引入教学策略在C语言的算法教学中的应用以及该教学策略在提高学生对抽象知识的理解,提高学生的分析问题、解决问题能力等方面的重要意义。     

货物单证处理微机系统

本文介绍了一套计算机应用软件系统。它可用于计算货物的运费、编制货物积载计划和缮制装货清单。这是在货物单证处理中工作难度和工作量最大的3项工作。本系统根据远洋运输生产的实际需要而设计。它包括4个功能系统和4个数据库。在输入操作中采用人机会话和菜单技术。本系统适用于远洋航运公司、船舶代理公司和杂货船。     

我院学生维生素营养状况的初步研究

对我院学生机体维生素A、维生素B_2和维生素C 的营养状况进行了研究。使用国产YA—Ⅱ型暗适应计对110人进行了维生素A 的测定,暗适应时间均值为48.04±21.03s;采用4h 维生素负荷试验,对43人进行了尿中维生素B_2和维生素C 的测定,尿中维生素B_2排出量男女分别为:1150.28±1837.50μg 和867.20±564.70μg,总缺乏率和不足率分别为20.9%和48.8%;尿中维生素C 排出量平均值为13.54±25.20mg,总缺乏率和不足率均为34.6%.     

The Cost-effectiveness of Preventive Conservation Actions

ABSTRACT

Two historic house museums, a municipal art gallery, and a provincial archive have had comprehensive risk and option assessments done by the Canadian Conservation Institute. For each institution, an average of 60 options addressing 40 risks was analyzed in terms of risk reduction, cost, and cost-effectiveness. A meta-analysis found that cost-effectiveness follows a strong economy of scale within each institution. By estimating valuation of each collection, cost-effectiveness was converted into benefit–cost ratio of dollar spent per dollar value saved and was found not to follow an economy of scale between small and large institutions. Optimization software was applied to see if precise maximization of risk reduction gave significantly different recommendations than those in the original reports which relied on the Pareto rule of addressing the largest risks first.     

聚苯乙烯负载二羧酸碘苯功能基的快速化学测定

本文提供了一种快速测定聚苯乙烯负载二羧酸碘苯功能基的方法———改进的碘量法,并应用于实践,效果优异,方法简便.