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。     

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     

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.     

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.     

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。     

Improved rigorous coupled-wave analysis for polar magnetic gratings

The rigorous coupled-wave analysis method with Airy-like Internal-Reflection Series for the polar gyrotropic grating is improved with the Fourier factorization rule. In the process of derivation, Maxwell's equation is reformulated in order to avoid type 3 product and, either Laurent's rule or the inverse rule is used for the product of two Fourier series with discontinuities. The number of Fourier coefficients or the size of the coefficient matrix required for the proper convergence is reduced by more than 50% compared to our previous works for the calculation of the diffracted Kerr rotation from the polar magnetic gratings.     

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。     

Simulation analysis of decision-making policy for on-demand transport systems

In recent years, on-demand transport systems (such as a demand-bus system) are focused as a new transport service in Japan. An on-demand vehicle visits pick-up and delivery points by door-to-door according to the occurrences of requests. This service can be regarded as a cooperative (or competitive) profit problem among transport vehicles. Thus, a decision-making for the problem is an important factor for the profits of vehicles (i.e., drivers). However, it is difficult to find an optimal solution of the problem, because there are some uncertain risks, e.g., the occurrence probability of requests and the selfishness of other rival vehicles. Therefore, this paper proposes a transport policy for on-demand vehicles to control the uncertain risks. First, we classify the profit of vehicles as “assured profit” and “potential profit”. Second, we propose a “profit policy” and “selection policy” based on the classification of the profits. Moreover, the selection policy can be classified into “greed”, “mixed”, “competitive”, and “cooperative”. These selection policies are represented by selection probabilities of the next visit points to cooperate or compete with other vehicles. Finally, we report simulation results and analyze the effectiveness of our proposal policies.     

Visualization tools for vorticity transport analysis in incompressible flow

Vortices are undesirable in many applications while indispensable in others. It is therefore of common interest to understand their mechanisms of creation. This paper aims at analyzing the transport of vorticity inside incompressible flow. The analysis is based on the vorticity equation and is performed along pathlines which are typically started in upstream direction from vortex regions. Different methods for the quantitative and explorative analysis of vorticity transport are presented and applied to CFD simulations of water turbines. Simulation quality is accounted for by including the errors of meshing and convergence into analysis and visualization. The obtained results are discussed and interpretations with respect to engineering questions are given.     

Three-dimensional and analytical modeling of microfluidic particle transport in magnetic fluids

We present an analytical model that can predict the three-dimensional (3D) transport of non-magnetic particles in magnetic fluids inside a microfluidic channel coupled with permanent magnets. The magnets produce a spatially non-uniform magnetic field that gives rise to a magnetic buoyancy force on the particles. Resulting 3D trajectories of the particles are obtained by (1) calculating the 3D magnetic buoyancy force exerted on the particles via an analytical distribution of magnetic fields as well as their gradients, together with a nonlinear magnetization model of the magnetic fluids, (2) deriving the 3D hydrodynamic viscous drag force on the particles with an analytical velocity profile of a low Reynolds number ferrohydrodynamic flow in the channel including “wall effect” and magnetoviscous effect of the magnetic fluids, and (3) constituting and solving the governing equations of motion for the particles using the analytical expressions of magnetic buoyancy force and hydrodynamic viscous drag force. We use such a model to study the particles’ trajectories in the channel and investigate the magnitude of their deflections at different flow rates, with different properties of magnetic fluids and different geometrical parameters of the system.     

眼压磁力连续测量原理与方法

为解决青光眼患者的24h眼压连续测量问题,提出了一种眼压磁力连续测量原理,采用2个永久磁铁同极靠近产生的排斥力对眼球施加压力,通过求解排斥力-距离曲线上波动点处的压力或波动点后的斜率计算得到眼压值.给出了测量系统结构及其磁排斥力仿真计算结果,对猪眼的实验结果显示,眼内压的大小和排斥力-距离曲线波动点处的压力值存在对应关...