基于FPGA的电泳式电子纸驱动芯片设计

为了克服专用驱动芯片成本居高不下及软件驱动方式占用大量处理器资源的缺点,在分析主流的电泳式电子纸驱动设计方法的基础上,针对电泳式电子纸的显示特性及接口规范,提出了基于FPGA及IP软核整合的通用驱动解决方案,开发出可以适应多种主控接口及多种电泳式电子纸接口的驱动芯片,并利用VerilogHDL编程以硬逻辑部署方式实现了波形表的设计。仿真及实验结果验证了设计的正确性,驱动芯片性能优异,成本低,兼容性好。     

8255A工作方式的课堂教学仿真演示

该文介绍了使用Proteus软件仿真典型接口芯片8255A课堂教学演示过程。用这一软件演示很清晰地反映了8255A的设置方式和工作过程。课堂教学实践表明:这种演示对清楚地讲解8255A接口芯片的工作过程很有帮助。     

基于集成压控振荡器的调频电路仿真分析

LM566是一种积分-施密特触发电路型的单片集成 VCO 芯片,在调频电路的教学中作为调制器和解调器,通过对其芯片的仿真,可以在软件平台形象的展示其工作特点,便于定量分析。由于Multisim元件库里没有LM566所需模型,为实现LM566在Multisim12仿真环境中的建模,首先,运用Multisim元件库中现有的基本元件模型,构建LM566芯片内部结构;然后,对外围调频电路的静态工作方式和动态工作方式的分析;最后,实验结果表明,给出的芯片模型能够客观的描述LM566的基本特性,为运用该芯片完成包括调频电路在内的各种功能电路的仿真分析奠定了基础,有效扩展了Multisim仿真软件的使用范围,具有一定的借鉴意义。     

CK·CORE嵌入式调试器接口设计

论文提出了一种基于片上仿真方式的调试器的硬件接口设计,为避免扫描链方法的问题,片上仿真模块采用映像寄存器方式实现,为了灵活性和可移植性,调试器软件采用了一种远程代理结构,所有硬件模块和软件模块都在拥有自主知识产权的32位高性能嵌入式CPU芯片CK·CORE配套调试器的设计中实现,并给出了与其他调试方式相比较的实验结果。     

基于反激式变换器AC-DC芯片的设计

采用0.5μm CMOS工艺,并结合当今电源管理芯片的发展趋势,设计了一款基于反激式变换器的低功率AC-DC电源管理芯片。该芯片在工作方式上采取以频率调制实现的恒流工作模式和以关断电压实现的恒压工作模式,并且集成了各种保护功能。利用Cadence仿真软件对各个模块电路进行仿真验证,使模块电路的性能达到系统的设计要求。     

基于VPI技术的全芯片混合仿真

仿真技术在IC设计的各个流程中都具有重要意义.基于纯软件描述语言(如C/C++)的仿真方法具有抽象层次灵活、仿真速度快等优点,但周期精确的模型库一般较难获取,而基于纯硬件描述语言如(Verilog HDL)的硬件前端仿真方法则具有周期精确、IP库充沛等优点,但其仿真速度一般较慢.因此,本文提出一种基于VPI技术的全芯片混合仿真方法,将软件模型与硬件模型灵活组合,通过桥接的方式实现软硬件混合仿真.该全芯片混合仿真平台既保证了系统周期精确的特性又维持了整个仿真系统的功能完整性,同时还大幅提升了仿真速度.最后在一款实际的工业级DSP设计中验证了该方法的有效性.     

51单片机与FPGA的UART通信模式研究

UART通信模式以其简单连接方式,可靠的传输效率广泛应用于现代化工业生产的各个方面,本文讨论的是51单片机与FPGA芯片的之间的UART通信模式。从二者的硬件连接,通信编程和软件仿真三个方面分析该模式的实现方式,并仿真了其实际通信效果,阐明了其实际可行性和使用可靠性。     

低电压芯片电泳过程中流场的模拟计算和分析

本文基于一种阵列电极的低工作电压电泳芯片分离模型,在其中微管道的电场模拟的基础上,结合微流体动力学特性,以分离管道侧壁排布电极并等间距施加电压,建立电泳芯片低工作电压分离过程的流场模型,利用CoventorWare软件分析单组分和双组分试样在微分离管道中流场的模拟,发现组分在常规电压和低工作电压两种分离模式下,其迁移速度近似相等;对于双组分,分离电压可大大降低同时,还可保证原来的分离度,低电压电泳过程中,工作电压可降低至30 V.证实了阵列电极和运动梯度场实现低电压电泳的可行性和有效性.     

芯片毛细管电泳的系统级建模与仿真技术研究

芯片毛细管电泳分离是微流控芯片系统中的重要组成部分,其电泳分离效率直接影响着芯片的整体功能。本文运用多端口组件模型技术建立了逶迤型芯片毛细管电泳分离的参数化行为模型及系统级模型。模型仿真结果与有限元仿真软件的仿真结果相比较,仿真速度提高了100多倍,而相对误差小于3.8%,表明论文所建立的芯片毛细管电泳分离行为模型,能够在不降低系统仿真精度的同时更加快速高效地对系统性能做出评价。     

基于Simulink的数模混合电路仿真平台设计与实现

针对数模混合电路仿真精度与性能之间的矛盾问题和仿真工业级复杂数模混合电路时仿真工具存在主流芯片和电路模块不足问题,提出了一种粘合模式的数模混合仿真平台模型架构,基于该架构设计并实现了一种基于Simulink软件,通过嵌入数字电路和模拟电路主流仿真引擎获得充足主流芯片和电路模块支持的数模混合电路仿真平台,设计了一种结合了拓扑排序算法的仿真控制方式,实现了对工业级复杂电路进行流程化、模块化的数模混合仿真;最后通过一个能够时序上可以逻辑拆分的典型数模混合电路仿真验证了仿真平台的有效性。     

Design and fabrication of poly(dimethylsiloxane) electrophoresis microchip with integrated electrodes

A novel poly(dimethylsiloxane) (PDMS) microchip integrated with platinum electrodes has been designed and fabricated using the Micro-electro-mechanical-systems (MEMS) technology. Since high voltage electrodes are integrated on the glass wafer using lift-off process, the microchip is a friendly-to-use system that does not need any extra mechanical apparatus for electrode insertion. To improve the sealing of microchip and ensure the uniformity of microchannel material, one PDMS membrane is formed on glass wafer with electrodes by pressing method. In this study, integrated microchip has been demonstrated as a capillary electrophoresis device for amino acids and satisfactory separation was achieved under separation electrical field strengths of 200 V/cm. The overall performance suggests that this novel microchip is advantageous and practical for the fabrication of lab-on-a-chip.     

Integrated structure of PMMA microchannels for DNA separation by microchip capillary electrophoresis

We proposed and fabricated an integrated structure of microchannels consists of three different functional PMMA layers for post-genome analysis, gene diagnosis, and screenings of useful materials for pharmaceutical. This integrated structure with 96 microchip capillary electrophoresis units in one chip is characterized as the simple structure with low cost and new aspects of the serial unit bio-chemical operation from DNA amplification to their analysis using microchip capillary electrophoresis. The design of the structure was performed using computational fluid dynamics, heat transmission, and electrophoresis simulation. To improve DNA separation resolution, microchannel with narrow width at the corner was adapted. The deep X-ray lithography process using synchrotron radiation “New SUBARU”, nano-imprint, and fusion bonding without bonding adhesive was applied for the fabrication of the integrated structure of microchannels. It was demonstrated that the proposed integrated structure of microchannels results in a good performance of the on-chip DNA amplification and separation in a small MCE unit area of 9 mm × 9 mm.     

Evaluation of micromilled metal mold masters for the replication of microchip electrophoresis devices

High-precision micromilling was assessed as a tool for the rapid fabrication of mold masters for replicating microchip devices in thermoplastics. As an example, microchip electrophoresis devices were hot embossed in poly(methylmethacrylate) (PMMA) from brass masters fabricated via micromilling. Specifically, sidewall roughness and milling topology limitations were investigated. Numerical simulations were performed to determine the effects of additional volumes present on injection plugs (i.e., shape, size, concentration profiles) due to curvature of the corners produced by micromilling. Elongation of the plug was not dramatic (< 20%) for injection crosses with radii of curvatures to channel width ratios less than 0.5. Use of stronger pinching potentials, as compared to sharp-corner injectors, were necessary in order to obtain short sample plugs. The sidewalls of the polymer microstructures were characterized by a maximum average roughness of 115 nm and mean peak height of 290 nm. Sidewall roughness had insignificant effects on the bulk EOF as it was statistically the same for PMMA microchannels with different aspect ratios compared to LiGA-prepared devices with a value of ca. 3.7 × 10⁻⁴ cm²/(V s). PMMA microchip electrophoresis devices were used for the separation of pUC19 Sau3AI double-stranded DNA. The plate numbers achieved in the micromilled-based chips exceeded 1 million/m and were comparable to the plate numbers obtained for the LiGA-prepared devices of similar geometry.     

Zone electrophoresis of proteins in poly(dimethylsiloxane) (PDMS) microchip coated with physically adsorbed amphiphilic phospholipid polymer

The zone electrophoresis of protein in poly(dimethylsiloxane) (PDMS) microchip coated with the physically adsorbed amphiphilic phospholipid polymer (PMMSi) was investigated. PMMSi was composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 3-(methacryloyloxy) propyltris (trimethylsiloxy) silane (MPTSSi) units in a random fashion. The membrane of PMMSi can be formed on the PDMS surface by a simple and quick dip-coating method. The membrane showed high hydrophilicity and good stability in water, as determined by contact angle measurement, fourier-transformed infrared absorption by attenuated total reflection (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. High suppression of protein adsorption to the PDMS surface and reduction in electroosmotic flow (EOF) were achieved by PMMSi coating due to an increase of hydrophilicity, and a decrease of the ζ-potential on the surface of PDMS. For zone electrophoresis, the PMMSi30 containing 30 % hydrophilic MPC was the most suitable molecular design in terms of the stability of the coated membrane on PDMS surface. The average value of EOF mobility of PDMS microchip coated with PMMSi30 was 1.4 × 10^?4 cm² V^?1 s^?1, and the RSD was 4.1 %. Zone electrophoresis of uranine was further demonstrated with high repeatability and reproducibility. Separation of two FITC-labeled proteins (BSA and insulin) was performed with high efficiency and resolution compared with non-treated PDMS microchip.     

A DNA trapping and extraction microchip using periodically crossed electrophoresis in a micropillar array

This paper presents an integrated deoxyribose nucleic acid (DNA) trapping and extraction microchip based on the electrophoresis using periodically crossed electric fields in the micropillar array. The extraction microchip, integrated with a micropillar array, microchannels, nano-gap entropic barriers, loading and unloading windows, has been fabricated by a 3-mask microfabrication process. Using the electric field crossed at 120°, the microchip is designed to trap the DNA molecules, whose reorientation time is longer than the period of the crossed field, within the micropillars distributed at 60° direction. In the fabricated extraction microchip, three different DNA molecules, including λ DNA (48.5 kbp), micrococcus DNA (115 kbp) and T4 DNA (168.9 kbp) show the reorientation times of 4.80 ± 0.44 s, 7.12 ± 0.75 s and 9.71 ± 0.30 s, respectively, at the crossed electric field of 6.25 V/cm. Among three DNA molecules, T4 DNA could not come out of the micropillar array for the electric field of 6.25 V/cm crossed at the period of 10 s. We have demonstrated that the present DNA extraction microchip separates DNA molecules larger than a critical value, which can be adjusted by the period of the electric field across the micropillar array.     

Inner surface modification of poly(dimethylsiloxane) microchannel with chitin for electrophoretic analysis of proteins

Microchip electrophoresis in a poly(dimethylsiloxane) microfluidic device is one of the versatile separation techniques in a micro total analysis system, while an unstable electroosmotic flow depending on an inner surface of a microchannel and a nonspecific adsorption of biogenic compounds onto the inner surface are often problematic in microchip electrophoresis. To overcome these drawbacks, a chitin-coated poly(dimethylsiloxane) microchannel was newly developed by a relatively simple experimental procedure based on vacuum drying. The obtained chitin-coating showed high durability during 10-times experiments with a stable electroosmotic flow. It was also confirmed that the chitin-coated poly(dimethylsiloxane) microchannel provided the pH-dependent electroosmotic flow related to the dissociations of amino and silanol groups of chitin and poly(dimethylsiloxane), respectively. The nonspecific adsorption of fluorescently labeled proteins onto the inner surface of the channel was well suppressed by the coating, resulting in the sharp and symmetric peak without tailing in the microchip electrophoretic analysis of proteins. The separation of the proteins was also demonstrated in the chitin-coated microchannel, so that the resolution and reproducibility of the migration time were improved as compared to those in the untreated microchannel.     

Fast fabrication of microfluidic devices using a low-cost prototyping method

Conventional ways to produce microfluidic devices cost a lot due to the requirements for cleanroom environments and expensive equipment, which prevents the wider applications of microfluidics in academia and in industry. In this paper, a dry film photoresist was utilized in a simple way to reduce the fabrication cost of microfluidic masters. Thus, a fast prototyping and fabrication of microstructures in polydimethylsiloxane microchips through a replica molding technology was achieved in a low-cost setting within 2.5 h. Subsequently, major manufacturing conditions were optimized to acquire well-resolved microfluidic molds, and the replicated microchips were validated to be of good performance. A T-junction channel microchip was fabricated by using a dry film master to generate water droplets of uniform target size. Meanwhile, a gated injection of fluorescein sodium and a contactless conductivity detection of Na⁺ were both performed in a crosslink channel microchip via capillary electrophoresis, in other words, this fast prototyping and fabrication method would be an efficient, economical way to embody structural design into microfluidic chips for various applications.     

Improving the separation efficiency of DNA biosamples in capillary electrophoresis microchips using high-voltage pulsed DC electric fields

This paper proposes a simple method for enhancing the separation efficiency of DNA biosamples in a capillary electrophoresis (CE) microchip by using high-voltage pulsed DC electric fields. A high-voltage amplifier is used to establish electric fields of up to 1 kHz to carry out CE separation; electrophoresis and electroosmotic effects are then pulsely induced. The experimental and numerical investigations commence by separating a mixed sample comprising two fluoresceins with virtually identical physical properties, namely Rhodamine B and Rhodamine 6G. It is found that the level of separation is approximately 2.1 times higher than that achieved using a conventional DC electric field of the same intensity. The performance of the proposed method is further evaluated by separating a DNA sample of HaeIII digested ΦX-174 ladder. The experimental results indicate that the separation level of the neighboring peaks 5a and 5b in the DNA marker is approximately 1.2, which is significantly higher than the value of 0.8 obtained using a CE scheme with a conventional DC electric field. The improved separation performance of the proposed pulsed DC electric field approach is attributed to a lower Joule heating effect as a result of a lower average power input and the opportunity for heat dissipation during the zero-voltage stage of the pulse cycle. Overall, the results demonstrate that the method proposed in this study provides a simple, low-cost technique for achieving a high separation performance in CE microchips.     

聚二甲基硅氧烷微流体芯片的制作技术

基于MEMS技术的微流体芯片在分析化学和生物医学领域显示了巨大的应用潜力。作为构建微流体芯片的基底材料———聚二甲基硅氧烷(PDMS)已经表现出了许多的优点:良好的电绝缘性、较高的热稳定性、优良的光学特性以及简单的加工工艺等。采用浇注法制作了PDMS电泳微芯片,对PDMS微流体芯片的加工工艺、封装方法和结构特征进行了探讨,并提出了相应的解决方案。     

Development of the automated gold-linked electrochemical immunoassay system for blood monitoring

This paper reports the development of fully automated miniaturized immunoassay system. The system consist of postage stamp sized microchip and compact (post card sized foot print) microchip driver. To realize easy sample loading into the microchip, surface modification of polydimethylsiloxane (PDMS) was developed, and life time of the modified surface up to 9 days is confirmed. The microchip just consumes a droplet of blood (2 μl) and the loading and metering of the sample is realized by capillary action, therefore the microchip is compatible with blood collection method by using lancet needle. Fully automated immunoassay protocol in the system is demonstrated within 15 min using whole blood sample. Finally, fully automated detection of antigen (insulin) was successfully demonstrated in the developed system.