An integrated microfluidic system for counting of CD4+/CD8+ T lymphocytes

This study reports on an integrated microfluidic system capable of counting CD4⁺/CD8⁺ T lymphocytes from a whole blood sample, which may be further applied for the rapid screening of the human immunodeficiency virus (HIV) infection. This system is composed of a sample incubation module for fluorescence-labeling of the target cells and a micro-fabricated flow cytometry module for cell counting. First, a pneumatically driven, vortex-type micro-mixer has been adopted for the fluorescence-labeling of CD4⁺/CD8⁺ T lymphocytes from whole blood. After the labeling process, different laser-excited fluorescent signals are detected and are used for counting of CD4⁺/CD8⁺ T lymphocytes as they pass through the detection region of the microflow cytometer. A concentration of 963 cells/μl is counted for cultured CD4⁺ T lymphocytes with a reference concentration of 1000 cells/μl. The ratio of CD4⁺/CD8⁺ T lymphocytes is then calculated. Experimental results show that the results from the microsystem are in agreement with the ones from large-scale flow cytometers. In addition, the entire diagnostic procedure, including the sample incubation and the cell counting, can be automatically performed within 35 min. Therefore, this may become a powerful tool for further biomedical applications, especially for fast screening of HIV infection.     

基于FPGA的多功能多路舵机控制器的实现

利用现场可编程门阵列(FPGA)构建了一个可编程片上系统(SOPC)实现能同时控制多个伺服舵机的控制器,用于遥控/自控飞艇的控制。该片上系统的硬件部分主要由串口通信模块、NIOS-IICPU模块、脉宽调制(PWM)信号发生模块、PWM信号脉宽计数模块以及多路开关模块组成。软件部分主要是串口通信软件。其中,PWM信号发生模块可通过串口通信灵活地设置每路PWM信号的占空比。仿真和实验结果表明,该控制器可根据串口通信数据,可靠地对每个伺服舵机进行独立控制,且舵机运行平稳无颤振。     

易损/危险品物流监测智能微系统

一种基于数据采集、射频识别的信息采集系统,可以采集存储物流过程中超过阈值的振动、湿度以及温度,并记录对应的时间,然后通过无线通信向外发送记录的数据。本系统由三部分组成,包括基于加速度传感器、温/湿度传感器的数据采集模块、基于RFID的无线通信模块及报警模块。本系统不仅可为易损邮寄物品保驾护航,还可对流通中的危险品状态进行实时监测,能应用于多种恶劣环境,实时将报警消息发送至运输人员手中,及时发现问题,提高运输效率,有效地降低运输货品的破损率和危险品的事故率。     

Knowledge based formation of re-configurable assembly cells

When developing assembly cells with highly complex modular structures, designers need to translate user requirements into a set of design rules and potential cell configurations. The success in matching user requirements to potential products is dependent on how well the functional and non-functional customer requirements can be understood and translated into cell features (design rules, processes and module types). This paper reports on a knowledge based methodology for forming customisable re-configurable assembly cells. The approach is based on matching user requirements to existing supplier knowledge in terms of design rules and principles, modules offered by different vendors, new emerging technologies and existing own and competitors’ products. The decision making includes requirements analysis, generating assembly processing alternatives and evaluating and selecting assembly modules and cells. The proposed approach aims to assist decision making in assembly system design by enabling users and suppliers to jointly participate in an interactive and iterative process of forming re-configurable assembly cells.     

Selective retrieval of microparticles in microchambers using electrolytically generated bubbles for cell array applications

This paper describes a method for the selective retrieval of microparticles using bubbles generated by electrolysis. Microparticles (polystyrene beads, mouse embryos, and cell spheroids) were arrayed in microchambers fabricated in SU-8 on the surface of an electrode consisting of indium tin oxide (ITO) patterned on glass. Bubbles were selectively generated in a target microchamber by applying a voltage to electrodes positioned in the microchamber. As a result, we successfully retrieved microparticles (100 μm in diameter) positioned in the microchambers. This method is gentle enough to maintain cellular viability, and therefore, it will be a powerful tool for the quantitative analysis of cells in an arrayed system.     

Combining fluidic reservoirs and optical tweezers to control beads/living cells contacts

We have developed a complete system based on holographic optical tweezers to realize multiple-point interactions between beads and cells with control of the stimulation places, timing and durations. We introduce microstereolithography as a 3D micromanufacturing approach to the rapid prototyping of three-dimensional fluidic microchambers of complex shapes, comprising wells, channels and walls, that are afterwards placed inside the sample and used to inject beads locally and keep them separated from cells in our assays. A custom reservoir designed to keep beads and cells separated in liquid samples has been realized and successfully tested. This allows us to deposit beads locally on the microscope cover glass placed under the reservoir outlet. Limited dispersion of beads under the outlet has been confirmed, and the ability of the polymeric structures to confine beads in a restricted area has been demonstrated. Examples of manipulations consisting at first in extracting several beads from the reservoir, making them travel to the target cell, and finally depositing on its outer membrane with respect to the shape of the target cell, are finally given.     

基于TMS320VC5402和XBee模块的UART应用研究

基于DSP的漏水检测仪器在实现漏点定位时需要使用无线通信模块,TI公司的TMS320VC5402只提供了同步串行接口McBSP,而无线模块XBee为异步串口。本文采用16倍过采样的方法,结合直接存储器访问（DMA）,通过对相关寄存器的适当配置,将McBSP软件模拟成通用异步接收／发送器（UART）,从而实现DSP与XBee模块的连接通信。再通过对XBee模块的适当配置,可将从机检测信号无线传给主机,在主机中处理两路信号,从而确定出漏点位置。试验得到的漏点位置在误差范围内,证明了该法的可行性。     

Manufacturing and packaging of sensors for their integration in avertical MCM microsystem for biomedical applications

Demonstrates the feasibility of integrating fragile micromachined chips into a complex three-dimensional (3-D) multichip module (MCM) microsystem for a biomedical application. The system is based on the vertical integration of the different parts: micropumps and valves, a multisensor chip for on-line control of the system and a signal-processing chip. In this paper, packaging of the microsystem is studied in order to minimize the induced stress that can affect the integrity of the different micromachined parts of the system. Standard commercially available components and materials were used so as to minimize costs for the case of high volume packaging. For testing the approach, a multisensor chip which includes thin silicon membrane-based devices has been used as the main test structure to compare different packaging materials. In addition, for the fabrication of such a sensor chip in an efficient mode, technological modules needed to fabricate sensors on complementary metal-oxide-semiconductor (CMOS) wafers are discussed. The definition of standardized "add-on" sensor modules to the CMOS process of a foundry is intended to limit the development cost of smart sensors     

一种新型的FPGA实现RS422串口通信方法

在FPGA实现RS422串口通信的常用方法中经常遇到诸多问题,如FIFO深度读取不正确、FIFO写数据端口与读数据端口时序竞争、多个模块间信号延时导致FPGA亚稳态等问题,因此设计了一种新型的RS422串口通信实现方法;该方法通过利用寄存器数组作为循环缓存代替FIFO,利用计数器代替传统的波特率产生模块,把常用方法中的多个模块整合成一个模块,只采用一个主时钟,所有寄存器的时钟输入端共享一个时钟,对FPGA逻辑与时序进行了有效约束,避免了FPGA中亚稳态产生;试验结果表明该方法实现的RS422串口通信高速、可靠、稳定,并且利用FPGA实现RS422串口通信,可使整个系统更为灵活、紧凑,减小整个电路的体积,提高系统的可靠性和稳定性。     

Visual Sensor with Resolution Enhancement by Mechanical Vibrations

The resolution limit of visual sensors due to finite pixel spacing can be overcome by applying continuous low-amplitude vibrations to the image—or taking advantage of existing vibrations in the environment. Thereby, spatial intensity gradients turn into temporal intensity fluctuations which can be detected and processed by every pixel independently from the others. This approach enhances resolution and virtually eliminates fixed-pattern noise. A visual sensing microsystem taking advantage of this principle is described. It incorporates a custom analog integrated circuit implementing an array of 32 by 32 pixels with local temporal signal processing. Another key component is a resonant mechanical device producing low-amplitude image scanning movements powered by environmental vibrations.     

基于SEP5010嵌入式系统中USB功能的实现

随着数字信号处理速度的提高,串口、并口已不能满足主机与嵌入式设备之阍的高速数据传输要求．设计了一种采用具有东南大学自主知识产权ARM9的SEP5010芯片硬件平台的USB系统功能,简单分析USB的驱动架构并在应用层中提出了新的传输协议,提出了一种对平台中的USB模块进行高性能读写的设计方案,使得USB模块达到了702KB／s的读写速度。同时此测试方案的不依赖于底层硬件,可以在适用于各种类型的硬件平台。     

Hierarchical design,laboratory prototype fabrication and machining tests of a novel 5-axis hybrid serial-parallel kinematic machine tool

Hybrid serial-parallel kinematic machine tool (HSPKMT) has been regarded as a promising solution for 5-axis machining in many industrial fields. A typical HSPKMT can be constructed by integrating a parallel functional module with a serial functional module. Following this way, the authors construct a novel 5-axis HSPKMT through the integration of an over constrained redundantly actuated parallel module with a stack-up serial gantry. The proposed HSPKMT can accomplish a 5-axis motion capacity with three translations and two rotations (3T2R). A hierarchical design method is proposed to facilitate the design issues of the 5-axis HSPKMT. According to the hierarchical method, a laboratory prototype is designed with a top-down strategy and then fabricated with a bottom-up strategy. An open-architecture computer numerical control (CNC) system is developed to drive the fabricated prototype. A kinematic analysis is carried out to reveal necessary kinematic properties of the proposed HSPKMT. The reachable workspace and task workspace are defined to graphically illustrate the machine's position-orientation capabilities. A workspace performance index is formulated to compare the proposed 5-axis HSPKMT with several 5-axis machine tools. Based the kinematic analysis, a 5-axis machining methodology is developed and further applied to the laboratory prototype to perform 5-axis machining tasks. The machining tests verify that the proposed novel HSPKMT possesses desirable 5-axis machining capability with the tolerance rang of ±0.05 mm. This also implies that the proposed hierarchical design method as well as the 5-axis machining methodology can be further applied to other types of HSPKMTs with minor modifications.     

Control flow and data flow oriented integration testing methods

The testing of modular software systems can be divided into a module testing phase and an integration testing phase. While module testing checks the modules separately, integration testing examines the use of interfaces in a modular system. Integration testing allows errors to be found which cannot be found by module testing. The aim of this paper is to propose a new approach to integration testing. The main principle is to transfer and adapt module testing methods to the level of integration testing. The approach is described for control flow and data flow oriented testing methods. To decrease the testing effort and increase the probability of finding errors, integration testing can be limited to statically detectable anomalous applications of interfaces. This is accomplished by the combination of static analysis with dynamic execution and by the possibility of using information already provided by the module tests. To find further test data to execute interfaces, symbolic execution is applied. One great advantage here is to prove whether statically determined interface anomalies can be dynamically executed and can therefore occur at all.     

基于SMS的智能家居远程控制模块设计

主要利用串口通信技术和 AT指令集设计一个基于短信(SMS)的远程控制模块。用户可通过手机发送短信实现对接入主机的家居设备控制。文章阐述该控制模块的硬件设计、PDU模式下短息编码规则、软件设计等内容,搭建一个以三星 S3C2440处理器为核心的控制平台用以完成对数据的分析和处理。该设计基于 GSM通信系统,保证了控制模块具有很强的可靠性和稳定性。该模块经实验测试验证了其可行性,为工程应用提供了一种解决方案。     

教室无线点阵显示系统的研究

主要介绍了教室无线点阵显示系统设计的具体方案。其适用于教室等多场所、多地域设置点阵屏,并要求同时即时获得信息的场合。无线点阵显示系统由上位机管理模块、无线发射与接收模块、LED点阵显示模块组成。上位机将信息通过RS232串口模块发送给无线发射模块,数据通过nRF905模块进行调制,并通过天线将数据发出。无线接收模块接收数据后通过I2C总线存储,再从24C02中取出数据通过I2C发送到相应点阵显示模块进行显示。     

The impact of serial correlation on testing for structural change in binary choice model: Monte Carlo evidence

This paper examines the finite sample properties of structural change tests with an unknown breakpoint for the probit model in the presence of serial correlation. The combination of structural change and serial correlation renders model estimation challenging, affecting the consistency of coefficient estimates. Although there is vast literature concerning structural change tests for linear time series models, the literature for such tests in the context of binary choice models is somewhat sparse. More importantly, the empirical literature has applied the standard tests of structural change on the discrete choice model, despite the fact that most of these tests were developed specifically for the linear regression model. Subsequently, the theoretical properties of these tests in the context of non-linear models are unknown. This includes the class of discrete choice models, such as probit and logit. The issue becomes even more complicated in the presence of serial correlation, since typical tests for structural change often require the assumption of independence in the error terms. Even when the tests allow for a weakly dependent structure in the data, their finite sample performance remains unknown. This paper conducts simulation analysis on the size of ‘supremum’ Wald, LR and LM tests for structural change in the context of the probit model with varying levels of serial correlation. It is found that the shortcomings of the tests in linear models are magnified in probit models. In particular, the tests exhibit greater size distortion for the probit model than the linear model with the same level of serial correlation. Bootstrapping is also considered as an alternative approach to obtaining critical values, and though it reduces the size distortion in finite samples, it is unable to accommodate the distortion associated with a high level of serial correlation.     

Collapse-free thermal bonding technique for large area microchambers in plastic lab-on-a-chip applications

Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length on the order of 1 mm and characteristic thickness on the order of 10–100 μm) without collapse by introducing a holed pressure equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique, two types of large area microchambers [(1) 20 × 10 mm and 40 μm thick and (2) 12 × 2.5 mm and 120 μm thick] with microchannels were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with the help of the HPEP.     

A Neural Approach for the Control of Piezoelectric Micromanipulation Robots

Micromanipulation has become an issue of primary importance in industry and biomedicine, since human manual capabilities are restricted to certain tolerances. The manipulation of biological cells or the assembly of a complete microsystem composed of different microcomponents are examples of the application of piezoelectric-driven microrobots. An automated microrobot-based micromanipulation desktop-station is developed by an interdisciplinary group at the University of Karlsruhe. The process of assembly takes place in the field of view of a light optical microscope. This paper focuses on motion control problems of the microrobots. The ability of an intelligent microsystem to adapt itself to the process requirements is of great importance, especially for assembly robots. The microrobots must be able to operate in a partially defined environment and to ensure reasonable behaviour in unpredicted situations. A neural control concept based on a reference model approach is proposed as a solution. It is shown, that the neural controller is able to learn the desired behaviour. It considerably outperforms an analytically designed linear controller. This is demonstrated both in simulation and in the real environment.     

通道与空间注意力图像超分辨率网络

单幅图像超分辨率（Single Image Super Resolution,SISR）在计算机视觉领域占有重要地位,该技术旨在从低分辨率图像中重建出高分辨率图像。近年来,深度神经网络在SISR领域起到了至关重要的作用,然而,目前利用卷积神经网络平等地对待高频与低频特征,使得高频细节的重建表现不佳,输出过于平滑,缺少纹理信息。另一方面,过于深的网络不容易收敛,并且随着神经网络的深度增长,来自前一层的长期信息很容易在后期层中减弱或丢失,使得重建收益不能正比于网络的深度与计算复杂度。针对以上问题,对用于SISR的卷积神经网络的基本块提出了空间注意力模块与通道注意力模块,在同一通道中,不同位置的信息被空间注意力模块赋予不同的权重,不同通道间的权重由通道注意力模块决定,这使得高频信息在重建任务中获得更高的地位,提高了重建指标。进一步地提出了长期特征调制模块将网络的层深度转化为块深度,大大缩小了网络深度,以解决前层长期信息的丢失问题。在Set5等多个基准数据集上的峰值信噪比（PSNR）均比目前其他基于深度卷积神经网络的方法有所提升,这证明了提出的方法的有效性与先进性。