Influence of geosynthetic reinforcement on the stability of an embankment with rigid columns embedded in an inclined underlying stratum

Incompressible dipping substrata are commonly encountered in engineering practice. Compared to horizontal underlying strata, the inclined underlying stratum increase the risk of collapse of embankments reinforced with columns because it weakens the restraint of the column base. The objective of this study is to investigate the effectiveness of geosynthetics on improving the embankment stability when the underlying stratum is inclined. The influence of geosynthetic tensile stiffness on the ultimate surcharge and failure mechanism is studied. A deep-seated failure with column tilting occurs when the geosynthetic tensile stiffness is low, whereas a lateral sliding occurs when the geosynthetic tensile stiffness is high. To illustrate the contribution of geosynthetics, the distribution of the lateral pressures acting on the columns is analyzed.     

Twenty-five years of natural coordinates

In the early eighties, the author and co-workers created and further developed the natural coordinates to describe the motion of 2-D and 3-D multibody systems. Natural coordinates do not need angles or angular parameters to define orientation, leading to constant inertia matrices and to the simplest form of the constraint equations. Natural coordinates are composed by the Cartesian coordinates of some points and the Cartesian components of some unit vectors distributed on the different bodies of the system. The points and vectors can be located in the joints, being shared by contiguous bodies, decreasing or even eliminating the need to set joint constraints and reducing the total number of variables. However, other authors prefer not to share variables in order to get even simpler equations and to keep a bigger decoupling of equations, which is preferable in some cases. In this paper the history of natural coordinates is reviewed, as well as the main contributions coming from other research groups. In the second part of the paper some application areas in which natural coordinates can be particularly advantageous are examined. Commemorative Contribution.     

LabVIEW机械故障诊断系统的Web实现

本文针对机械设备远程故障诊断的振动数据分析问题,设计了一种在Web浏览器中进行机械设备振动数据实时显示和频谱分析的方法。首先,LabVIEW程序通过以太网从工业现场采集实时振动数据并以网络共享变量发布;然后,LabVIEW Web Service服务程序根据用户请求获取实时振动波形数据或对数据进行频谱分析,将数据以XML方式返回;最后,客户端的浏览器中分别采用Flex和Ajax对XML进行解析并显示实时波形和特征参数。该方法快速、稳定、可靠,很好地解决了远程故障诊断的问题。     

考虑材料参数的刚粘塑性有限元初始速度场自动生成方法

本文采用一种包含材料硬化指数ｎ和速率敏感性指数ｍ的刚粘塑性有限元模型，阶段硬化处理考虑到等效应力公与应变率有关，依据线粘性材料假设，提出了考虑材料参数ｎ、ｍ影响的刚粘塑性有限元初始速度场自动生成方法，改进了文献［３］方法。数值模拟结果与有关文献的计算和实验结果进行了比较，表明本文方法是有效的。     

圆柱体平板镦粗应力场的有限元分析

应用刚粘塑性有限元法对圆柱体在两平板间镦粗时的应力场进行了分析 ,给出了毛坯在不同初始高径比时的心部应力随压下量的变化曲线。由此得出 :在变形过程中 ,圆柱体心部存在两向拉应力 ;并且在墩粗过程中 ,当瞬时高径比约为 1 .0时 ,心部σθ、σr 由拉应力转变为压应力。     

Online learning and fusion of orientation appearance models for robust rigid object tracking

We introduce a robust framework for learning and fusing of orientation appearance models based on both texture and depth information for rigid object tracking. Our framework fuses data obtained from a standard visual camera and dense depth maps obtained by low-cost consumer depth cameras such as the Kinect. To combine these two completely different modalities, we propose to use features that do not depend on the data representation: angles. More specifically, our framework combines image gradient orientations as extracted from intensity images with the directions of surface normals computed from dense depth fields. We propose to capture the correlations between the obtained orientation appearance models using a fusion approach motivated by the original Active Appearance Models (AAMs). To incorporate these features in a learning framework, we use a robust kernel based on the Euler representation of angles which does not require off-line training, and can be efficiently implemented online. The robustness of learning from orientation appearance models is presented both theoretically and experimentally in this work. This kernel enables us to cope with gross measurement errors, missing data as well as other typical problems such as illumination changes and occlusions. By combining the proposed models with a particle filter, the proposed framework was used for performing 2D plus 3D rigid object tracking, achieving robust performance in very difficult tracking scenarios including extreme pose variations.     

德国用环戊烷代替氟里昂（CFC）作为硬质PU泡沫发泡剂的新技术

本文介绍了环戊烷的运输，多元醇／环戊烷混合装置及混合料储存的技术并详细叙述使用环戊烷作为发泡剂的安全方法。     

基于ApacheFlex的企业项目管理应用

本文通过具体项目,讲解Flex在企业RIA解决方案中的应用和技术特点。     

MBS机构的UML建模与计算机仿真

利用面向对象的设计方法和多刚体系统动力学方法，利用UML(Unified Modeling Language)统一建模语言建立多体机构模型，结合机构实例进行计算机仿真，取得了很好的仿真效果。