大跨度拱桥缆索吊装系统的稳定性有限元分析

基于结构稳定理论,介绍了在结构稳定性分析中有限单元法的求解原理及求解过程.以彭水乌江大桥缆索吊装系统为工程背景,考虑起吊、运输等状态,及风荷载,按塔架的最不利受力组合进行分析,对其塔架的稳定性进行有限元分析,通过多次迭代求解得出了该吊装系统在最不利施工工况下塔架的屈曲临界荷载系数和失稳模态,为该桥的施工控制提供了理论基础.     

多发性骨髓瘤预后因素的COX模型分析

为探讨影响多发性骨髓瘤患者生存的危险因素，用ＣＯＸ模型对７１例多发性骨髓瘤患者的１５项临床及实验室指标进行了单、多因素回归，结果筛选出两项显著性指标，即血肌酐及尿素氮水平升高是影响骨髓瘤预后的危险因素。并进一步分析了骨髓瘤肾功损害与诸因素的关系，发现骨髓瘤所造成的继发性损害如贫血、感染、高血钙、尿ＢＪＰ（本一周蛋白）均与肾功能不全有关，提示可用肾功能损害程度综合反映骨髓瘤患者的生存预后。     

Rural speed limit changes and safety

There is little information in the literature on the relation between rural speed and safety. The wide variation in rural speed limits that are applied in different countries tends to confirm that this relation is poorly understood. The changes in fatal, injury and all accidents that followed a change in the rural speed limit in seven countries were regressed against the change in vehicle mean speed. The results showed that speed significantly affects safety and that within certain limits the relation is linear. The regressions indicated that a 1 km/h reduction in speed will reduce all severities of accidents by between 4 and 5%. It is suggested that part of this reduction is due to a change in economic factors.     

基于环境因素和基准化原理的信息资源配置研究

针对维修信息资源特点，以装备维修系统投入、产出为双目标，兼顾决策者偏好，引入环境背景值及针对多阶段过程的时间窗，建立装备维修信息资源优化配置DEA模型，并采用基准化思想评价资源配置效率。算例分析结果符合实际，最优结果和效率评价分析为决策者提供决策支持，利于提高装备维修保障效用，充分发挥装备维修资源作用。     

农村客运运力配置的影响因素探析

农村客运运力配置不仅是农村客运规划中的重要内容，也是制定客运规划的主要因素之一，其主要包括运力规模配置和运力结构配置两个方面的内容。系统分析影响农村客运运力配置的内、外部因素，可以全面了解农村客运运力规划需考虑的各种问题，从而有助于制定更加科学、更加合理的农村客运运力发展规划，也有助于使农村客运发展的实施过程更加有序化、更加合理化。     

摩托车燃油蒸发污染物排放测试浅析（1）

要保证燃油蒸发测试的准确性，首先应确保车辆状态的稳定，包括炭罐的老化、炭罐正常的吸附、脱附，及油气管路的正确连接等。对燃油蒸发测试结果影响最大的因素是油品和试验用油的蒸气压，只有在试验用油和燃油蒸气压一致的条件下，各种测试结果才有可比性。因此，日后在进行燃油蒸发试验时应重点关注燃油的蒸气压。     

One manufacturer's approach to improving jet transport fuel efficiency

In the face of rapidly escalating costs of aircraft fuel, since the early 1970s, the aerospace industry has embarked on a program of measures to reduce fuel consumption. This article describes an integrated set of measures which have been undertaken by Lockheed‐California to improve the fuel requirements of the Tristar, a wide‐bodied three engine medium to long range aircraft. Measures include operational changes, improvements to maintenance practices, long term hardware modifications and technological advances.     

On stress concentration factors for tubular Y- and T-Joints in frame structures

This paper is written as a result of some years experience with fatigue analysis of offshore jacket structures where the connections are made as tubular joints. The hot spot stresses at the tubular joints in such analysis are normally derived based on parametric equations for stress concentration factors. These stress concentration factors are normally related to the axial force in the brace. It is observed that the hot spot stresses at the crown positions of the tubular joint in some cases are significantly affected by the local loading on the chord and the bending moment in the chord. In order to use the existing formulae in these cases some engineering effort is required to derive correct hot spot stress. This work can be avoided by using the nominal stress in the chord as the basis for calculating the hot spot stress at the crown position instead of using the axial force in the brace as basis for the analysis. This also extends the validity of the equations for stress concentration factors for T- and Y- joints in design standards. The proposed modification makes it also simpler to include the effect of joint flexibility in a proper way. The basis for a proposed revision of the equations for stress concentration factors for these joints is presented in this paper. It is considered that this modification leads to minor changes of the computer code, but that it will save analysis work for engineers and reduce the possibility of calculating incorrect fatigue lives in tubular frame structures.     

高速公路隧道交通安全评估研究

主要介绍了高速公路隧道交通安全评估的理论与方法。隧道交通安全评估主要分为两个方面:一是安全风险评估,二是安全潜力评估。通过对高速公路隧道交通事故进行分析,得出影响隧道交通安全的风险因素,并针对各风险因素,找出可减少事故发生概率和减轻事故严重程度的安全保障措施。根据各种不同情况下所产生的风险因素及相应的安全保障措施,分别给出了安全风险参数和安全潜力参数的评分标准,及隧道安全评估参数的计算方法。最后应用模糊评价的方法,代入隧道安全评估参数,对隧道的交通安全状况进行评价。     

乌鲁木齐低液限粉性土击实试验影响因素分析

通过乌鲁木齐低液限粉性土的击实试验研究,阐述了土样制备方法及含水量和击实功对干密度的影响,建议按具体情况确定经济击实功。讨论了击实筒余土高度的变化对击实试验结果的影响,并提出击实过程中最后一层土按余土高度为4 mm估算,通过修正余土高度的影响,减小试验误差。