Unified spray, foam and air bubbles for particle-based fluids

We present a new model for diffuse material, i.e. water–air mixtures, that can be combined with particle-based fluids. Diffuse material is uniformly represented with particles which are classified into spray, foam and air bubbles. Physically motivated rules are employed to generate, advect and dissipate diffuse material. The approach is realized as a post-processing step which enables efficient processing and versatile handling. As interparticle forces and the influence of diffuse material onto the fluid are neglected, large numbers of diffuse particles are efficiently processed to realize highly detailed small-scale effects. The presented results show that our approach can significantly improve the visual realism of large-scale fluid simulations.     

用于微型阀的磁性双稳态系统作用力研究

为了降低微型阀功耗,提出了一种新型磁性双稳态系统。该系统由两块钕铁硼材料环形永磁体和一片软磁片组成,其中软磁片选用钢和坡莫合金作为考查材料。采用有限元仿真的方法对软磁片受到的磁场力进行分析,结果显示:当软磁片半径较永磁体半径偏大10%左右时能够获得磁场力极值,同时通过调整两块永磁体之间的距离,软磁片所受到的磁场力能够比单永磁体作用下的受力大30%以上。对软磁片受力进行了测试并与有限元分析结果进行了比较,吻合较好,实验表明:该磁性双稳态系统能够很好地应用在微型阀当中。     

Smart urban freight transport: tools for planning and optimising delivery operations

Delivery bay availability for loading and unloading operations is critical to reduce times and costs of logistics operations, as well as for improving city sustainability and liveability. Beyond defining the appropriate number and location of such bays, urban sustainability and liveability can be improved with telematics tools which enable real-time bay reservation and monitoring, integrating such information within freight routing solutions. This paper presents an architecture for such tools along with methodology integrating delivery bay planning with transportation demand modelling through simulation, allowing computation of performance indicators to be used for ex-ante assessment in planning delivery scenarios. The results were validated through a simulation-based approach on Rome's limited traffic zone.     

Stability analysis of position and force control for robot arms

Stability issues involving the control of a robot arm under the influence of external forces are discussed. Several different scenarios are considered: position control with the external force as an unmodeled disturbance, compliant control for a bounded external force in some subspace, and compliant control for a force due to the interaction with an environment whose dynamical behavior can be modeled. In each of these cases, a stability analysis using the Lyapunov method is presented. An explanation of instability is suggested in the case that the environment has flexibility and the gains are inappropriately chosen. When the environment is stiff in the force control subspace, robust (in time delay) stability can be achieved via the integral force feedback. However, the integral feedback gain should be chosen sufficiently small to account for possible flexibility in the system     

考虑随机运能和送到时限的高铁快递运输计划优化方法

为充分利用高铁非高峰期的列车运能,高铁快运已成为铁路快捷货运发展新趋势.然而,受客运需求波动影响,载客动车组可用于高铁快递的运能呈现高度不确定性,给日常运营组织带来巨大挑战.为增强高铁快运系统应对随机运能的能力,提出一种考虑随机运能的高铁快递运输计划优化方法.首先,采用离散场景刻画列车运能的不确定性,以最大化高铁快运期望总收益为目标,综合考虑快递的送到时限和运营约束,针对场景概率分布精确已知情形,构建两阶段随机规划模型(SP);然后,进一步考虑场景概率分布信息部分已知情形,构建两阶段分布鲁棒优化模型(DRO),基于盒式模糊集,借助对偶理论将DRO模型转化为等价的整数线性规划模型并利用GUROBI求解;最后,基于宁杭高铁设计数值实验验证模型的有效性,结果表明,相较于SP模型,DRO模型体现出较强的鲁棒性,只需付出较小的代价即可有效抵抗运能波动对运输计划的影响,并且能够改善最坏情形下解的质量,切实改善高铁快递实际运营中的稳定性.     

Flow control for cell growth by movement of magnetic particles utilizing electromagnetic force

Three-dimensional (3D) cell structures are required to fabricate artificial organ. Inkjet technology is applied for fabrication of 3D cell structures in order to fabricate artificial organ and investigate biochemical characteristics of cells in 3D cell structures. Usually cells located inside 3D cell structures get nutrition via blood vessels. In case that there are no blood vessels in the 3D cell structures, cells located inside the 3D cell structures will die of nutrition shortage. So, blood vessels are essential to fabricate 3D cell structures. When the amount and flow of nutrition is controlled, growth speed of cells will be changed. We control the flow around the cells utilizing magnetic particles and magnetic force. The magnetic particles are installed in the dish that is filled with medium, nutrition and living cells. When the magnetic particles are trapped and transported by magnetic force, the cell growth will be controlled. In this paper, we challenge to control the flow utilizing magnetic particles and magnetic force.     

基于无线传感系统的斜拉桥索力测试与分析

斜拉索是桥梁的重要构件,它的索力值大小是评估桥梁整体性能的重要指标。本文研制了基于ZIGBEE技术标准的桥梁索力检测的无线传感系统,给出了利用振动频谱法测定索力的原理,介绍了系统的总体结构及模块化设计,进行了斜拉桥模型和现场斜拉桥的索力测试实验。实验表明,所开发的无线传感系统能够准确地进行索力值检测,从而为桥梁的安全性能评估提供了保障,具有简便实用、布设快捷等特点,具有较好的应用前景。     

Software for analysis of equine ground reaction force data

Software for analysis of force plate recordings of the horse at normal walk is described. The data of a number of stance phases are averaged to obtain a representative tracing of that horse. The amplitudes of a number of characteristic peaks in the force-time curves are used to compare left and right front limbs and left and right hind limbs. The averaged tracings are plotted, default on the line printer or, via separate program, on a high quality pen plotter. A version of the program applicable for analysis of human force plate recordings, is available.     

Using atomic force microscopy for deep submicron failure analysis

As circuit feature size continues to shrink, we will soon need a failure analysis technique that provides resolutions of 10 nanometers or less. This feasibility study concludes that AFM technology, with reasonable improvements, can take over where focused ion beams leave off     

Electronic Mosquito: designing a semi-invasive Microsystem for blood sampling, analysis and drug delivery applications

In this study we present an innovative design idea for a semi-invasive blood sampling, analysis and drug delivery device called “Electronic Mosquito” (“e-Mosquito”). The major building blocks of the device are discussed. The principle of operation is described and its feasibility is demonstrated. The integration of the microsystem is outlined and its practical implementation proposed.     

带时间窗的整车多式联运模型研究与解析*

限时性的快速货物运输已成为货运发展的趋势之一,多式联运则是较佳的运输组织形式。针对我国汽车消费市场飞速发展的大环境,以实现汽车整车时效性物流费用最小化为目的,建立了时间和容量约束下的多式联运方式0-1整数规划模型,根据模型的特点,设计了自然数编码的遗传算法,最后结合实例检验了模型和算法的有效性。     

Formal analysis of some secure procedures for certificate delivery

This paper describes and formally analyses two communication protocols that manage the secure emission of digital certificates. The formal analysis is carried out by means of a software tool for the automatic verification of cryptographic protocols with finite behaviour. The tool is able to discover, at a conceptual level, attacks against security procedures. The methodology is general enough to be applied to several kinds of cryptographic procedures and protocols. It is the opinion of the authors that this approach contributes towards a better understanding of the structure and aims of a protocol, for developers, analysers and final users. Copyright © 2005 John Wiley & Sons, Ltd.     

Energy minimization versus pseudo force technique for nonlinear structural analysis

The effectiveness of using minimization techniques for the solution of nonlinear structural analysis problems is discussed and demonstrated by comparison with the conventional pseudo force technique. The comparison involves nonlinear problems with a relatively few degrees of freedom. A survey of the state-of-the-art of algorithms for unconstrained minimization reveals that extension of the technique to large scale nonlinear systems is possible.     

Continuous force field analysis for generalized gradient vector flow field

We propose a modification of the generalized gradient vector flow field techniques based on a continuous force field analysis. At every iteration the generalized gradient vector flow method obtains a new, improved vector field. However, the numerical procedure always employs the original image to calculate the gradients used in the source term. The basic idea developed in this paper is to use the resulting vector field to obtain an improved edge map and use it to calculate a new gradient based source term. The improved edge map is evaluated by new continuous force field analysis techniques inspired by a preceding discrete version. The approach leads to a better convergence and better segmentation accuracy as compared to several conventional gradient vector flow type methods.     

二维微载荷传感器的设计与分析

设计了一种二维微载荷传感器。用于仿生粘性材料的力学性能测试,也可用于一般的摩擦试验。利用应力集中原则对平行梁弹性体局部削弱,结合材料力学理论和有限元软件ANSYS对弹性体进行仿真设计。利用ANSYS后处理器中提供的路径映射技术,在弹性体应变最大的区域,确定弹性体应变计的最佳贴片位置。对传感器进行静态标定,得出其静态性能指标,其垂直方向的最大量程为3.0 N,分辨力为0.008 N;水平方向的最大量程为3.5 N,分辨力为0.01 N。     

消化道定点施药系统的磁定位数据采集程序设计

设计了一种消化道定点施药系统的磁定位数据采集程序,利用Visual C++.Net开发工具开发了基于USB接口的数据采集程序,采用多线程、双缓冲存储技术和面向对象的程序设计方法,实现了施药系统的磁定位数据实时采集和对采集数据的处理与存储等功能,利用内存设备环境和多视图编程方式实现多样化的人机交互界面。实验结果表明:该数据采集程序可以实现多通道数据采集,单通道采样时间小于10μs,能够实时、稳定、正确地获取磁定位数据。