黄土增湿湿陷过程的三维有效应力分析

通过非饱和原状黄土湿陷增湿及孔隙压力特性试验得到的黄土增湿过程中的有效应力－应变关系，采用三维非线数值分析方法，对黄土地基从天然状态到非饱和增湿湿陷，直到饱和湿隐的全过程进行了分析，初步得出了黄土陷全过程的变形、应力转换等规律，是黄土湿陷性研究的一次有益的尝试，对评价地基在不同浸水程度下的湿陷变形有重要的意义。     

Cu-1.0Cr自生复合材料的水平连铸过程及组织

利用自行研制的高梯度定向凝固水平连铸设备对Cu-1.0Cr自生复合材料的制备过程进行了研究.结果表明,炉口温度、冷却强度、连铸速度等参数相互匹配对合金固液两相区的控制尤为重要,也直接影响连铸线材的表面质量和内在定向组织;在稳定凝固速率为245μm/s时,内部组织形貌为共晶相(α β),与初生α相平行、沿轴向均匀呈连续纤维层状排布,而在低速凝固过程中,初生α相呈现为胞状组织特征,其长大方向受热流方向的约束.     

非饱和原状黄土三轴试验方法研究

作者用组装的非饱和土三轴仪，以武功黄土为研究对象，探讨了非饱和原状黄土三轴压缩试验方法，并通过对５种饱和度、在５个围 压下的三轴压缩试验成果，初步分析了非饱和黄土破坏时水气演化规律。     

高等院校校园环境改造探索——以“丘园”景观设计为例

教育事业的发展为高等院校发展带来了契机,最为直接的表现就是校园物质环境质量有了较大的提高。我国有许多历史悠久的高等院校也都在致力于校园环境的建设。高等院校校园环境改造中如何保留历史和人文的气息,使文脉得以延续的同时又符合时代的发展要求是值得重视的问题。本文利用一个典型的案例进行了有关理论的探讨。一、引言我国的高等教育事业近年来得到了快速发展。许多历史悠久的院校也都与时代共同发展,最为直接的表现就是校园物质环境的改善。校园环境改造是多数学校在发展过程中采取的措施之一,使学校面貌得以较快改观。但是,不容…     

气粉流喷吹熔池的通用数学模型

根据气粉液三相流的质量守恒和动量守恒，推导出适用于气粉流顶吹中，侧吹和底吹熔池的通用数学模型。     

Weighted empirical likelihood estimates and their robustness properties

Maximum likelihood methods are by far the most popular methods for deriving statistical estimators. However, parametric likelihoods require distributional specifications. The empirical likelihood is a nonparametric likelihood function that does not require such distributional assumptions, but is otherwise analogous to its parametric counterpart. Both likelihoods assume that the random variables are independent with a common distribution. A nonparametric likelihood function for data that are independent, but not necessarily identically distributed is introduced. The contaminated normal density is used to compare the robustness properties of weighted empirical likelihood estimators to empirical likelihood estimators. It is shown that as the contamination level of the sample increases, the root mean squared error of the empirical likelihood estimator for the mean increases. Conversely, the root mean squared error of the weighted empirical likelihood estimator for the mean remains closer to the theoretical root mean squared error.     

自生TiC颗粒增强钛基复合材料的研究进展

从自生TiC颗粒增强钛基复合材料（PTMCs）的制备方法、微观组织及界面结构、性能和应用与展望4个方面论述了自生TiC颗粒增强钛基复合材料的研究进展。重点介绍了近年来PTMCs的一些制备方法及在室温、高温时的力学性能。     

小型NYAB脉冲激光器和双向倍压移相调压式泵浦源

本文阐述了以双向倍压移相调压式泵浦源泵浦的新型自倍频激光晶体NYAB小型脉冲激光器的结构、泵浦源的线路组成、泵浦源技术指标和有关设计依据、光泵的辐射光谱与自倍频激光工作物质NYAB晶体吸收光谱的匹配以及为适应NYAB晶体的荧光寿命而选配泵浦光的光脉冲宽度等问题。     

黄土力学性质研究的发展和展望

本文从理论体系上总结了黄土力学性质研究发展的主要成就,同时建议了该领域的发展方向,供同行在以后研究工作中参考。     

A hazard-based duration model for analyzing crossing behavior of cyclists and electric bike riders at signalized intersections

This paper presents a hazard-based duration approach to investigate riders’ waiting times, violation hazards, associated risk factors, and their differences between cyclists and electric bike riders at signalized intersections. A total of 2322 two-wheeled riders approaching the intersections during red light periods were observed in Beijing, China. The data were classified into censored and uncensored data to distinguish between safe crossing and red-light running behavior. The results indicated that the red-light crossing behavior of most riders was dependent on waiting time. They were inclined to terminate waiting behavior and run against the traffic light with the increase of waiting duration. Over half of the observed riders cannot endure 49 s or longer. 25% of the riders can endure 97 s or longer. Rider type, gender, waiting position, conformity tendency and crossing traffic volume were identified to have significant effects on riders’ waiting times and violation hazards. Electric bike riders were found to be more sensitive to the external risk factors such as other riders’ crossing behavior and crossing traffic volume than cyclists. Moreover, unobserved heterogeneity was examined in the proposed models. The finding of this paper can explain when and why cyclists and electric bike riders run against the red light at intersections. The results of this paper are useful for traffic design and management agencies to implement strategies to enhance the safety of riders.