面向精度分析的全语义产品模型研究

为了利用计算机技术辅助产品的精度设计,提出了计算机辅助精度分析的概念,阐述了其分类、内容和方法,并建立了一种面向狭义计算机辅助精度分析的3维产品模型——全语义产品模型。按照产品层次的不同,将该模型分为零件级和装配级两类,因而在构造不同类型的模型时需要附加不同层面的信息,并将这些信息转化为相应的邻接矩阵形式,存储在产品的相应模型文件中,这样,全语义产品模型弥补了基于特征设计的几何模型的缺陷,能够提供精度要求、尺寸公差、形位公差、表面粗糙度和装配约束关系等方面精度分析所需的信息,为实现计算机辅助精度分析提供基础模型。该模型已成功用于自主开发的计算机辅助精度分析系统中。     

PC微流控芯片黏接筋与溶剂的协同辅助键合

为了在微流控芯片上形成封闭的微通道等功能单元,克服热压键合中微流控结构的塌陷和热压所致芯片微翘曲对后续键合的影响,提出了一种适用于硬质聚合物微流控芯片的黏接筋与溶剂协同辅助的键合方法。以聚碳酸酯(PC)微流控芯片为研究对象,通过热压法在PC微流控芯片上的微通道两侧制作凸起的黏接筋,通过化学溶剂丙酮微溶PC圆片的表面,然后将PC圆片与带有黏接筋的PC微流控芯片贴合、加压、加热,从而实现微流控芯片的键合。分析了键合机理,并对键合工艺参数进行了优化。实验结果表明:键合质量受丙酮溶剂溶解PC圆片的时间和键合温度的影响,能够保证键合质量的最佳键合温度为80~90°,溶解时间为35~45s,芯片的键合总耗时为3min。与已有键合工艺相比,所提出的黏接筋与溶剂辅助键合工艺有效提高了键合效率。该键合方法不仅适用于具有不同宽度尺寸微通道的微流控芯片,还可扩展用于不同材料的硬质聚合物微流控芯片。     

Multi‐Functional Particle Detection with Embedded Optical Fibers in a Poly(dimethylsiloxane) Chip

Abstract

This paper describes a polydimethylsiloxane microfluidic chip with embedded optical fibers for particle detection. It consists of a microchannel for sample delivery, two pairs of fibers for multi‐functional particle detection, and electrodes for high voltage supply to generate electrokinetic particle motion. A small size semiconductor laser and a Si‐PIN detector are used for optical detection. The detection system allows easy switch between two‐fiber detection mode and one‐fiber detection mode, and is capable of counting particles, measuring particle velocity, and identifying particle sizes in a single polydimethylsiloxane chip. The technique described here is potentially applicable to a range of particulate diagnostic systems.     

Microfluidic channel depth determination with Tywman–Green interferometer

A microfluidic channel is fabricated on a silica wafer using reactive ion etching (RIE). The depth of the microfluidic channel has been measured using a surface profilometer and a Twyman–Green interferometer (TGI) setup. The TGI setup which mainly consists of a 660-nm wavelength He-Ne laser source, glass cube beam splitter and two prisms produced interference fringes based on the optical path difference between two interfering beams when the microfluidic channel is inserted into one of the beams. The TGI setup that was developed has shown high repeatability when measuring microfluidic channel depth and also eliminates back injection into the laser source and alignment criticality. The TGI setup applied a single photodiode to detect the shifting of the bright and dark fringe produced from the interference of the TGI. The depth of microfluidic channel obtained from the TGI is 1.79?±?0.31 μm using fringe shifting and intensity measurements, while according to the surface profilometer the depth of microfluidic channel obtained is 1.67?±?0.07 μm. The resolution of the TGI is 0.25 μm and can still go well below that depending on the wavelength of the laser source. This research describes the capability of the TGI to perform depth measurements on a microfluidic channel of a silica substrate which can also be improvised for other microscale devices and applications.     

微流体机械全流场数字粒子图像测速技术

提出了一种针对MEMS技术制造的微流体机械全流场数字粒子图像测速技术,通过添加荧光显微装置,改进照明光源以及示踪粒子的选型等解决微观检测的关键问题。针对微流体特征尺度小、精度要求高的特点,讨论了基于互相关原理的速度矢量识别算法。并就微流体检测中引起主要误差的示踪粒子布朗运动效应提出了全体平均图像处理方法。     

基于Micro-PIV的微观流场检测技术

介绍了一种针对微观流场检测数字粒子图像测速技术,通过添加荧光显微装置,改进激光入射与照明方式、聚焦平面控制以及纳米级示踪粒子布朗运动误差消除算法等软硬件方面的技术创新,解决了微观检测的关键问题。针对微流体特征尺度小、精度要求高的特点,建立了具有自主知识产权的Micro－PIV微流场测试平台,并就几种典型微观流场进行了检测。试验结果表明该测试技术可对微米级稳态、瞬变流场进行全流场速度分布的检测,各项性能指标达到国际先进水平。     

Geometric optimization for a thermal microfluidic chip

A geometric design for a microfluidic chip using numerical simulation is presented. Finite element method was employed in order to design the microchannel configuration for a microfluidic chip array. The effect of geometry on the thermal response at the interface between the microfluidic chips and an integrated system, such as a micro-electronic device, was investigated. Dimensionless design charts, obtained from the parametric models, demonstrated that a compromise between a maximum heat transfer and a minimum interface temperature was achieved with an equilateral triangle cross-section at a microchannel spacing to width ratio of two. The transient response of the microfluidic chip implied that the transient analysis corresponded to the steady state results under different boundary conditions.     

微流场可视化测速技术及其应用

介绍了一种针对微观流场检测数字粒子图像测速技术，通过添加荧光显微装置，改进激光入射与照明方式及聚焦平面控制，解决了微观检测的关键问题。对微流体器件中几种典型微管道进行了理论与试验研究，并定量对比与分析了仿真与试验结果，结果显示Micro—PIV是适合于微米级流场检测的有效试验手段。     

Combining multiple optical trapping with microflow manipulation for the rapid bioanalytics on microparticles in a chip

An array of four independent laser traps is combined with a polydimethylsiloxane microfluidic chip to form a very compact system allowing parallel processing of biological objects. Strong three dimensional trapping allows holding objects such as functionalized beads in flows at speeds near 1 mm/s, enabling rapid processing. By pressure control of the inlet flows, the trapped objects can be put in contact with different solutions for analysis purpose. This setup, including a fluorescence excitation-detection scheme, offers the potential to perform complex biochemical manipulations on an ensemble of microparticles.     

聚合物微流控芯片激光加工及建模研究

在CO2激光直写聚合物PMMA微流控芯片加工原理基础上，对建立激光直写PMMA微流道的数学模型进行了研究。采用能量守恒原理对激光直写PMMA微流道成形进行分析，结果表明其微流道的形状呈高斯函数型分布，并获得了微流道深度与激光功率、加工速度及加工次数的函数关系模型。实验数据较好地验证了所建模型的正确性，该模型对CO2激光直写聚合物微流控芯片的加工参数选择具有较好的指导作用。     

A discrete PSO for two-stage assembly scheduling problem

In this paper, a discrete particle swarm optimization (PSO) algorithm called DPSO is proposed to solve the two-stage assembly scheduling problem with respect to bicriteria of makespan and mean completion time where setup times are treated as separate from processing times. In DPSO, the particle velocity representation is redefined, and particle movement is modified accordingly. In order to refrain from the shortcoming of premature convergence, individual intensity is defined, which is used to control adaptive mutation of the particle, and mutation mode is decided by the individual fitness. Furthermore, a randomized exchange neighborhood search is introduced to enhance the local search ability of the particle and increase the convergence speed. Finally, the proposed algorithm is tested on different scale problems and compared with the proposed efficient algorithms in the literature recently. The results show that DPSO is an effective and efficient for assembly scheduling problem.     

微流控芯片光学检测系统集成化新进展

微流控芯片是微全分析系统(μTAS)中当前最活跃的领域和发展前沿。目前人们在微流控芯片的研究中已经取得了很大的进展,研制出了多种微型化、集成化的芯片。相比之下,与微流控芯片配套的高灵敏度微型光学检测系统的研制却相对落后。介绍了分别基于CMOS、垂直腔面发射激光器(VCSEL)和微型雪崩光电二极管(μAPD)来实现光学检测系统与微流控芯片集成化的方法。     

基于Matlab的动力总成悬置系统参数优化设计

在推导了动力总成悬置系统固有频率及固有振型计算过程的基础上,分析并设置了系统各阶固有频率的范围,采用能量法解耦理论及序列二次规划(SQP)优化算法,利用Matlab编写出优化程序,对动力总成悬置系统进行了解耦设计.实例计算表明,通过该方法可使悬置系统解耦程度明显提高,有效地改善了车辆乘坐的舒适性.     

非对称截面螺旋流道中微粒的惯性聚焦效应

为实现生物微粒/细胞的精确操控,提出了一种非对称截面螺旋流道结构的惯性微流控芯片.基于仿真和实验的方法,对不同尺寸微粒在微流道中的惯性聚焦行为进行了研究.设计了一种"L"形截面的螺旋流道,采用仿真软件COMSOL研究微流道中的二次流场及微粒的运动轨迹.使用UV激光切割与等离子清洗键合的工艺制作芯片样件,采用高速摄像机和...     

基于AMESim的新型PDMS微阀动态特性仿真研究

针对一种新型的可用于气动微流控芯片气压控制的电磁致动微阀的进一步研究和应用问题,在阐述了其结构和工作原理的基础上,利用AMESim软件建立了相应的动态仿真模型,对其流量、压力动态特性进行了分析,并且给出了该种微阀和传统气动电磁阀的流量、压力动态特性的对比分析结果.该种新型的电磁致动微阀由微流控芯片的上层PDMS平膜、具有微流道的下层PDMS厚膜和电磁致动器构成,电磁致动器通过安装在阀座上的玻璃片与PDMS微流控芯片实现了集成.而且,采用这种集成化的新型微阀的控制方式相较于传统采用气动电磁阀的控制方式,具有成本低、体积小、易于与微流控芯片集成等优点.研究结果表明,采用这种新型PDMS微阀对微流控芯片进行驱动和控制可以获得较好的动态特性,并且该研究对电磁致动微阀的进一步研究和应用提供了一定的理论指导.     

基于CO_2激光雕刻机的微流控分析芯片快速制造系统的研究

本文介绍一种在对现有微流控芯片加工方法进行综述的基础上,利用激光雕刻加工微流控芯片的方法。基于CO2激光雕刻机控制器原理及图像处理理论,开发研究针对BMP图像文件格式适用于激光雕刻的软件,通过图形处理生成加工路径文件后,经过再处理得到插补数据,利用半步偏差-几何最优法插补程序实现对X,Y轴步进电机和激光电源的控制,从而实现雕刻加工,将激光雕刻加工出的盖片和基片进行键合,从而制作出微流控芯片。     

多工位装配序列粒子群优化算法

针对传统单工位装配序列求解上的不足,将粒子群算法应用于多工位多目标装配序列优化的求解,提出一种面向复杂多工位产品的装配序列优化方法。采用优先序列图(Assembly precedence graph,APG)来描述零件间的优先约束关系,构建优先关系矩阵、装配干涉矩阵、工位能力表和装配信息表,描述装配部件干涉及工位之间的关系;给出粒子群算法编码体系和装配关系算法模型表达方法;综合考虑装配操作成本、装配工具更换成本和装配夹装变更成本和运输成本的影响,提出有工程意义的适应度函数的表达式;根据APG生成随机的可行初始装配序列,并利用粒子群算法(Particle swarm algorithm,PSO)对装配序列和装配工位进行优化。以飞机起落架装配序列规划实例验证多工位粒子群装配序列优化算法有效性。     

Patterned wafer bonding using ultraviolet adhesive

The process of patterned wafer bonding using ultraviolet (UV) adhesive as the intermediate layer was studied. By presetting the UV adhesive guide-layer, controlling the thickness of the intermediate layer (1– 1.5 μm), appropriate pre-drying temperature (60°C), and predrying time (6 min), we obtained the intermediate layer bonding of patterned quartz/quartz. Experimental results indicate that patterned wafer bonding using UV adhesive is achieved under room temperature. The process also has advantages of easy operation, low cost, and no plugging or leakage in the patterned area after bonding. Using the process, a microfluidic chip for red blood cell counting was designed and fabricated. Patterned wafer bonding using UV adhesive will have great potential in the fabrication of microfluidic chips.     

双桥系统的推力杆平衡及弹性支撑的分析

首先介绍了重型汽车平衡悬架用推力杆的工作原理,建立了重型汽车平衡悬架用推力杆的简单受力模型。当中桥车轮受到冲击载荷跳起时,计算中桥和后桥上推力杆的轴向力并校核推力杆的强度。当只有后桥右车轮抬起时,计算后桥上推力杆的扭矩应力并校核其强度。然后,分别建立推力杆总成、壳体、连接杆和小轴的CATIA模型。接着,在以上分析计算结果的基础上,分别对它们进行ANSYS分析。     

基于微螺线管电感式传感器的金属颗粒形态对输出特性影响的研究

基于电感测量技术与微流体技术的油液检测芯片, 不仅可以区分出铁磁性和非铁磁性金属颗粒, 还可以对油液中的颗粒进行计数统计和颗粒大小测量,从而判断金属颗粒污染物的来源及设备的磨损状态。通过理论分析、数值模拟及实验验证, 分析不同形态铁磁颗粒退磁场, 研究铁磁颗粒形态对电感式传感器的输出影响。建立理论模型描述不同形状颗粒的退磁因子、磁化场, 以及磁化的金属颗粒产生磁场从而导致线圈电感发生变化。基于模型计算并验证同体积下球形、不同轴长比的圆柱、椭球颗粒的磁场和电感输出, 分析结果显示颗粒越细长、退磁因子越小则越容易磁化, 因此细长颗粒引起传感器的电感变化更大, 另外圆柱形颗粒的电感变化大于旋转椭球型颗粒。