Unsteady fluid mechanics effects in water based human locomotion

Computational fluid mechanics (CFD) has made substantial progress on modelling a variety of important problems in industry. However, there is still lack of reliable methods to model the motion of the body in water. This is a central issue in understanding animal and human propulsion in water not only to advance science but to explore the possibility of utilising such propulsion modes for man made vehicles. The presented work identified the added mass effect as the prime contributor to propulsive force generation. The use of boundary element method (BEM) proved very successful as it allowed reducing this dynamic problem to a quasi-static one without sacrificing accuracy in the model. The comparison between the experimental data and the simulation result was in the range of 95% (average accuracy) suggesting that the added mass effect and dynamic lift and drag are the most significant physical phenomena in propulsive force generation despite the fact that there is undoubtedly and the presence of turbulent effects that were not considered.     

Apparent mass matrix of standing subjects exposed to multi-axial whole-body vibration

This paper describes the experimental characterisation of the apparent mass matrix of eight male subjects in standing position and the identification of nonlinearities under both mono-axial and dual-axis whole-body vibration. The nonlinear behaviour of the response was studied using the conditioned response techniques considering models of increasing complexity. Results showed that the cross-axis terms are comparable to the diagonal terms. The contribution of the nonlinear effects are minor and can be endorsed to the change of modal parameters during the tests. The nonlinearity generated by the vibration magnitude is more evident in the subject response, since magnitude-dependent effects in the population are overlaid by the scatter in the subjects’ biometric data. The biodynamic response is influenced by the addition of a secondary vibration axis and, in case of dual-axis vibrations, the overall magnitude has a marginal contribution.

Practitioner Summary: We have measured both the diagonal and cross-axis elements of the apparent mass matrix. The effect of nonlinearities and the simultaneous presence of vibration along two axes are smaller than the inter-subject variability.     

MC环境下基于案例推理的零件相似度与工时估算研究

在MC环境下,为了使零件工时快速且准确的被估算出,以案例推理理论为基础,研究了零件相似度与工时之间的内在关系,提出了零件相似度的工时估算新方法。首先,通过CASE检索法和零件拓扑结构相似度在规范的案例库中检索并筛选出符合要求的相似零件样本;其次,根据零件相似性机理,确定零件相似度的内涵,构建零件相似度的计算模型,即零件拓扑结构相似度计算模型和零件特性相似度计算模型;最后,通过Matlab软件确定零件相似度与工时之间的关系函数,从而实现定制零件加工时间的快速估算,并用实例验证了该方法的有效性和可行性。     

高速U盘病毒隔离器的设计与实现

U盘的普及使U盘病毒繁衍迅速,针对信息系统安全保护的需要,设计出一种U盘病毒隔离器。该隔离器具有隔离Autorun病毒、防止PC的数据通过U盘泄密、防止PC中的病毒感染U盘的功能。隔离器能够快速捕获到U盘与主机之间所有底层数据,在此基础上,隔离器中的微控制器(MCU)通过分析、审计和过滤流过隔离器中的底层数据来实现上述功能。经实际检测,该设计能够实现上述功能。     

滑坡体临滑声发射监测主机的设计

基于滑坡体临滑时因岩石断裂、岩石摩擦而产生声发射的特点,提出一种基于声发射监测的滑坡体临滑监测主机的设计方案。系统能监测的声发射频率范围为1Hz～20kHz,能监测的最小声压为0.002Pa。通过安装在滑坡体附近的声发射传感器,连续监测和记录滑坡体临滑时产生的声发射,可用于分析其变化规律和特征,从而实现对滑坡灾害的预测预报。     

Analysis of image sticking on a real MVA Cell

Abstract— Image‐sticking phenomenon is one of the most important issues affecting LCDs, especially LCD TV. It is known that image sticking is caused by residual DC voltage. An analysis of the cause that induces image sticking on a real LCD cell is very difficult to perform and is rarely reported. In this paper, the impurities that cause boundary image sticking on a real MVA cell was analyzed by examining a cross section of a cell, the bulk LC layer, the vicinity of the LC layer, the LC layer/PI alignment film interface using microanalysis methods such as infrared micro‐spectroscopy (μ‐IR) and micro‐sampling mass spectrometry (μ‐MS). It is clarified that there is quite a bit of aromatic acid at the boundary of the image‐sticking area than in the normal area at the LC/PI alignment film interface on the color‐filter side, not the TFT side, and it is assumed that aromatic carboxylic acid, a negative charged material, is condensed at the LC/PI alignment film interface on the color filter side by an electrically driven DC component inducing an electric‐condenser residual DC voltage.     

The application of a proportional difference type iterative learning control in active vibration control

Active vibration control is used to instead passive solutions in order to increase the performance at low frequencies, in a variety of different engineering systems. This method has improved the performance specifically. The paper will propose a proportional difference type iterative learning control algorithm to deal with the periodic sources and to investigate the active solution as the three degrees of freedom ＂mass spring damping＂ mount. Simulation shows that this method could get a better tracking performance, also the displacement could converge to zero with a fast speed.     

Development of 2D computer program to determine geometry of rock mass blocks简

Due to various geological processes such as tectonic activities fractures might be created in rock mass body which causes creation of blocks with different shapes and sizes in the rock body. Exact understanding of these blocks geometry is an essential issue concerned in different domains of rock engineering such as support system of underground spaces built in jointed rock masses, design of blasting pattern, optimization of fragmentation, determination of cube blocks in quarry mines, blocks stability, etc. The aim of this paper is to develop a computer program to determine geometry of rock mass blocks in two dimensional spaces. In this article, the geometry of jointed rock mass is programmed in MATLAB™.     

TDM平台的海量试验数据展现优化

为了满足新的试验数据展现应用的需求,综合试验数据量大、试验数据展现灵活性、交互性等因素,提出了一种基于XML技术的海量试验数据展现的思路.对TDM理念以及TDM关键技术作简要介绍,在此基础上,通过分析主流的试验数据展现方式,指出目前试验数据展现存在的问题和弊端.针对这些弊端,结合控件、XML、OpenGL等多种技术阐述了海量试验数据展现的解决方案,并讨论了如何使TDM平台中的试验数据后处理功能具有丰富的交互性、强大的展现逻辑和良好的用户体验.