A microfluidic device for array patterning by perpendicular electrokinetic focusing

This paper describes a microfluidic chip in which two perpendicular laminar-flow streams can be operated to sequentially address the surface of a flow-chamber with semi-parallel sample streams. The sample streams can be controlled in position and width by the method of electrokinetic focusing. For this purpose, each of the two streams is sandwiched by two parallel sheath flow streams containing just a buffer solution. The streams are being electroosmotically pumped, allowing a simple chip design and a setup with no moving parts. Positioning of the streams was adjusted in real-time by controlling the applied voltages according to an analytical model. The perpendicular focusing gives rise to overlapping regions, which, by combinatorial (bio) chemistry, might be used for fabrication of spot arrays of immobilized proteins and other biomolecules. Since the patterning procedure is done in a closed, liquid filled flow-structure, array spots will never be exposed to air and are prevented from drying. With this device configuration, it was possible to visualize an array of 49 spots on a surface area of 1 mm². This article describes the principle, fabrication, experimental results, analytical modeling and numerical simulations of the microfluidic chip.     

High-throughput battery materials testing based on test cell arrays and dispense/jet printed electrodes

A cost effective and reliable technology for the fabrication of electrochemical test-cell arrays for battery materials research, based on batch-fabricated glass micro packages was developed and tested. Jet dispensing was investigated for the first time as a process for fabricating battery electrode arrays and separators and compared to micro dispense printing. The process shows the reproducibility over the whole range of investigated materials and battery cell structures that is required for battery materials research. Such setup gives rise to a significantly improved reliability and reproducibility of electrochemical experiments. Cost-effective fabrication of our test chips by batch processing allows for their single-use in electrochemical experiments, thereby preventing contamination issues due to repeated use as in conventional laboratory test cells. In addition, the integration of micro pseudo reference electrodes is demonstrated. Thus, the test cell array together with the developed electrode/electrolyte deposition technology provide a highly efficient tool for speedy combinatorial and high throughput testing of battery materials on a system level (full cell tests). Experimental results are shown for the microfabrication of lithium-ion test cells with help of several electrode and binder materials. The influence of jetting parameters on electrode lateral dimensions and thickness, reproducibility of the electrode mass as well as the use of integrated micro-reference electrodes for impedance spectroscopy and cyclic voltammetry measurements in micro cells are presented in detail.

     

Wafer‐scale monolithic hybrid integration of Si‐based IC and III–V epi‐layers—A mass manufacturable approach for active matrix micro‐LED micro‐displays

Hybridization of silicon integrated circuits (ICs) with compound semiconductor device arrays are crucial for making functional hybrid chips, which are found to have enormous applications in many areas. Although widely used in manufacturing hybrid chips, the flip‐chip technology suffers from several limitations that are difficult to overcome, especially when the demand is raised to make functional hybrid chips with higher device array density without sacrificing the chip footprint. To address those issues, Beida Jade Bird Display Limited has developed its unique wafer‐level monolithic hybrid integration technology and demonstrated its advantages in making large‐scale hybrid integration of functional device arrays on Si IC wafers. Active matrix micro‐light‐emitting diode micro‐displays with a resolution of 5000+ pixel per inch were successfully fabricated using Beida Jade Bird Display Limited's monolithic hybrid integration technology. The general fabrication method is described, and the result is presented in this paper. The fabricated monochromatic micro‐light‐emitting diode micro‐displays exhibit improved device performance than do other micro‐display technologies and have great potentials in applications such as portable projectors and near‐to‐eye projection for augmented reality. More importantly, the wafer‐scale monolithic hybrid integration technology offers a clear path for low‐cost mass production of hybrid optoelectronic IC chips.     

Pulse‐width modulation with current uniformization for AM‐OLED micro‐displays on Si LSI chips

We have developed pulse‐width modulation (PWM) with current uniformization for active‐matrix organic light‐emitting diode (AM‐OLED) micro‐displays on Si large‐scale integration (LSI) chips. This driving method can simultaneously solve luminance unevenness and image sticking due to characteristic deviations and degradations of driving transistors and OLEDs. With the use of circuit simulation, it is verified that the PWM with current uniformization (PWM‐CU) can simultaneously achieve precise gray scale and exceedingly improve luminance uniformity. Moreover, an actual panel is designed and fabricated, where the OLEDs are layered on the Si LSI chip. It is found that the luminance uniformity can be improved within 2% to 3%. It is meaningful that the correct images can be displayed using the PWM‐CU for the first time for AM‐OLED micro‐displays on Si LSI chips.     

基于MSP430的硒鼓芯片复位装置的设计

针对激光打印耗材生产厂家硒鼓生产过程中需对硒鼓芯片进行再利用的问题,设计了一种基于MSP430的硒鼓芯片复位装置.利用该装置可以复位不同型号的硒鼓芯片,从而使硒鼓芯片可循环利用,以达到节约生产成本、保护环境的目的.该装置同时具有复位效果好、易于操作的优点.     

Monolithic fabrication of electro-fluidic polymer microchips

Integration of electronic wiring with microfluidic chips is an important process as it allows electrical interactions with the fluidic media, for example required for resistive and capacitive sensing. It is also necessary in order to implement various actuation and control mechanisms such as pumping, electrophoresis and temperature control. Typically electrical wire traces are added to microfabricated fluidic chips using metal deposition processes that are carried out after the fluidic chip has been fabricated. The process for adding the wiring is complicated and is limited to select metals that can be deposited by evaporation or sputtering. We present a single step method for integrating electrical wires into polymer microfluidic chips that are fabricated by a hot embossing process. This process can flexibly embed any kind of commercially available metal wire with a microfluidic chip and the wiring may be integrated to come into surface contact with the fluid or may be embedded in close proximity to (but insulated from)the fluid paths for example for local heating purposes. This method significantly reduces total processing time and is thus a valuable method for wire integration into polymer chips. We demonstrate two applications—a microelectrolysis chip and a heater chip that were fabricated using this methodology. The design, fabrication process and the initial test results are presented.     

RNA amplification chip with parallel microchannels and droplet positioning using capillary valves

We present results from the MicroActive project which develops an instrument for molecular diagnostics. The instrument is first tested for patient screening for a group of viruses causing cervical cancer. Two disposable polymer chips with reagents stored on-chip are developed and will be inserted into the instrument for each patient sample analysis. The first chip will perform nucleic acid extraction from patient epithelial cervical cells, while mRNA amplification and fluorescent detection takes place in the second chip. This paper reports results on the amplification chip. Purified sample is inserted into the chip and split into ten smaller droplets for simultaneous amplification and detection of ten viruses. The droplets move in parallel channels, each with two chamber extensions containing dried reagents. Experimental results on parallel droplet movement using one external pump combined with hydrophobic restrictions show that the parallel droplet positions can be controlled. There are four valves with increasing burst pressures between 800 and 4,500 Pa in each parallel channel, positioning the droplets in metering zones and reaction chambers. The re-hydration times for the dried reagents in micro chambers have been monitored. After sample insertion, uniform concentration of the reagents in the droplet was reached after respectively 60 s and 10 min. These times are acceptable for successful amplification. Finally we show positive amplification of HPV type 16 viruses in a micro chamber.     

采用最大修改字节重定向写入策略的相变存储器延寿方法

现代存储系统一般是由多个存储芯片通过并列数据线、共享地址线的方式构成的.因此,在多片相变存储芯片并联构成的内存系统中,如果多个芯片间的磨损存在较大差异,那么该系统的寿命将会因短板效应而受到影响.模拟实验和数据分析均确认了这一问题在实际系统中的存在.在此基础上,提出了一种混合内存设计,用于延长相变内存的寿命.该方法引入了一种动态识别机制,可以在每次写入时识别遭受最多磨损的相变存储芯片,并将该芯片未来的写入转移到另一个长寿命的存储芯片中.这一措施可以减少对相变存储芯片的总写入量,并缩小相变存储芯片间的写入量差别.实验表明：使用RMB设计的内存系统的寿命最多可达无任何寿命延长方法时的7.9倍,可达使用经典方法PRES的5.14倍.     

Manufacture of microfluidic chips using a gap-control method based on traditional 3D printing technique

The solution to the commercialization of polymer microfluidic chips lies in the development of a low-cost and concise method. We present in this paper a gap-control method for obtaining low cost microfluidic chips on PMMA (polymethyl methacrylate) sheets based on traditional 3D printing technique—fused deposition modeling. The influence of 3D printing parameters such as printing temperature, printing speed, wire flow rate and initial layer thickness on printing quality is studied by experiments. The effect of O₂ plasma parameters such as chamber power and treatment time on the adhesion strength between printed PLA (polylactic acid) structures and PMMA substrate is investigated. The dye filling tests demonstrate that there is no blocking or leakage over the entire microchannels. With this newly developed technology, low-cost and large scale microfluidic chips can be fabricated, which allows commercial manufacturing of microchannels over large areas.

     

Implementation of a Sliding Memory Plane Image Processor

This paper presents architectures and implementation of a Sliding Memory Plane (SliM) Image Processor to build a SIMD parallel computer. The paper also proposes an enhanced multiplication algorithm to reduce the gate count and the number of cycles. The SliM chip consists of mesh-connected 5×5 PEs. Due to the idea ofsliding, that is, overlapping the inter-PE communication time with the computation time, SliM can greatly reduce the inter-PE communication overhead. In addition, four operations corresponding to ALU, shift, data I/O, and inter-PE communication can be grouped into an instruction to be executed in a cycle simultaneously. The implemented SliM chip operates at 25 MHz and gives 625 MIPS. Because of a mesh topology, a large number of chips can be easily connected to form a SIMD parallel computer. We have implemented the scalable SliM Array Processor and developed parallel algorithms for real-time image processing.     

新型快速准分子激光微加工方法制备毛细管电泳芯片的研究

选用聚合材料聚甲基丙烯酸甲酯(PMMA)代替玻璃,石英等作为毛细管电泳芯片的基片材料.在19 kV,5 Hz及5mm/min的加工参数下,采用新型快速准分子激光微加工方法完成了毛细管电泳芯片的制备.实验结果表明该方法加工过程简单,耗时短,自动化程度高,有效提高了芯片成品率和加工质量.芯片与相同尺寸的盖片在105℃、160 N、恒温20 min条件下通过热压键合在一起,得到密闭性好的整体芯片.最后在芯片上应用激光诱导荧光检测法对Cy5染料完成了分离检测,获得了重复性很好的检测信息.     

Nano-slit electrospray emitters fabricated by a micro- to nanofluidic via technology

This article presents nano-slit electrospray emitters fabricated by a micro- to nanofluidic via technology. The main advantage of the technology is the ability to position freely suspended nanochannels anywhere on a microfluidic chip, where leak-tight delivery of fluid from a fluid reservoir can be established through long microchannels. The technology has proven to be useful in creating electrospray emitters coupled to freely suspended microchannels. It was observed that filling of nanochannels through via connections with integrated microchannels occurs not only due to bulk capillary action. These observations lead to a redesign of the electrospray chips. Repeatable electrospray IV-curves could be obtained from fabricated nano-slit electrospray emitters. Moreover, integration of on-chip microfluidic components is one of the possibilities of the fluidic via technology presented.     

Temperature modeling and measurement of an electrokinetic separation chip

This work presents experimental [infrared (IR) thermography] and computational (finite element model) results of temperature distributions of an electrokinetic separation chip. Thermal characteristics of both the electrolyte solution and the polymer chip (SU-8) are taken into account in modeling temperature distributions during electrokinetic flow. Multiphysics and multiscale simulation couples electrostatics, heat transfer, and fluid dynamics. The accompanying IR thermography is a non-contact method, which can measure fractional temperature differences with sub-second time resolution. Any structures or temperature marker molecules interfering with the experiment are not needed. Nominal spot size in the IR measurements is 30 μm with a field of view of several millimeters enabling both local and chip-scale temperature monitoring simultaneously. As a result, we present a computer model for electrokinetic chips, which enables simulation of fractional temperature changes during electrophoresis under real operating conditions. The accuracy of the model is within ±1°C when the deviation in electrochemical processes is taken into account. The simulation results also suggest that the temperature on the chip surface qualitatively reflects the temperature inside the microchannel with an average offset of 1–2°C.     

A spectral imaging array biosensor and its application in detection of leukemia cell

A new type of array immunosensor was developed by combining surface plasmon resonance (SPR) and spectral imaging techniques. The system consisted of a monochromator as the wavelength scanning light source, a polarizer, Kretschmann-Raaether attenuated total reflection (ATR) configuration including array sensor chip, and a CCD camera. The images of transmitting light from ATR were recorded versus the wavelength. By averaging gray scales of the pixels in the area of every gold spot from the image series, the complete spectral resonance curve of all sensing spots on the array can be extracted in parallel. The performance of the developed system was evaluated by analyzing interactions of the anti-CD33 monoclonal antibody to its target leukemic cells using 11 cases of human bone marrow specimens. The specimens were also analyzed with flow cytometry method (FCM) for comparison. The initial results measured by the immunosensor array were corresponded with that of FCM, indicating that the developed parallel method might be clinically suitable for immunophenotyping of acute leukemias. The new sensor array system showed the merits of high-throughput, high sensitivity, high specificity, label free and operation convenient. Spots numbers of the array could be increased if suitable technology were adopted for manipulating the micro bio-liquids on the sensor array chip.     

A Novel PDMS Microfluidic Spotter for Fabrication of Protein Chips and Microarrays

A novel polydimethyl siloxane (PDMS) microfluidic spotter system has been developed for the patterning of surface microarrays that require individually addressing each spot area and high probe density. Microfluidic channels are used to address each spot region, and large spot arrays can be addressed in parallel. Fluorescence intensity measurement of dye-spotted samples compared to control and pipetted drops demonstrated a minimum of three-fold increase in dye surface density compared to pin-spotted dyes. Surface plasmon resonance (SPR) measurement of protein-spotted samples as compared to pin-spotted samples demonstrated an 86-fold increase in protein surface concentration. The spotting system has been applied successfully to protein microarrays for SPR applications, in both a 12-spot linear and 48-spot two-dimensional (2-D) array format. This novel spotter system can be applied to the production of high-throughput arrays in the fields of genomics, proteomics, immunoassays, and fluorescence or luminescence assays.1565     

A diagnosis algorithm for constant degree structures and itsapplication to VLSI circuit testing

A simple diagnosis algorithm is presented for constant degree systems such as rectangular grids connected as tori. The algorithm determines the status of a unit according to the size of its faction, a cluster of units that call each other fault-free but outsiders faulty. Almost all units are correctly identified with this algorithm under a binomial failure distribution even when the probability of failure is rather high. The complexity of the algorithm is O(n), where n is the number of units in a constant degree system. The application of the algorithm to production testing of VLSI chips is also considered. With a test board that houses a large number of chips to be tested, all the chips can be tested in parallel in a way that they test each other and the test outcomes, not necessarily correct, are reported to a host system for analysis. The actual status of each chip is determined by using this new diagnosis algorithm. The above chip screening process can be repeated for higher accuracy. It is shown that no more than two steps are needed in most real situations. Compared with testing by test equipment that usually tests only one chip at a time, the saving of test time and the test equipment cost could be significant with our approach     

模型引导的分层与连续相结合的3D打印

在面曝光连续3D打印中,由于在有限的时间内,树脂填充距离有限,因此,打印实心结构过程中容易因为树脂填充不足而导致打印失败,连续成型适用于镂空结构或者薄片结构.另外,由于存在润滑液流失,基于浸泡润滑液的聚二甲基硅氧烷膜的连续打印高度受限.针对上述问题,该文提出了一种在模型引导下分层打印和连续打印相结合的数字光处理技术3D...     

一种结合硬件特征的并行内存故障检测方案

针对March类内存检测算法越来越复杂、检测时间越来越长,且更适用于对嵌入式内存芯片的检测等问题,提出一种结合硬件特征的并行内存故障检测方案。该方案包括2种并行检测方法:(1)根据DDR2的结构和工作原理设计的芯片级并行,可以并行检测一个DDR2内部的多个内存芯片。(2)根据访存控制器的结构和工作原理设计的访存控制器级并行,可并行检测多个DDR2内存条。对于芯片级并行,访存带宽越大,即并行检测的芯片个数越多,并行效果越好,从1个芯片到并行检测8个芯片,内存的检测时间几乎是呈线性递减的。对于访存控制器级并行,访存控制器数量越多并行效果越好,从1个LMC到2个LMC,内存的检测时间几乎减少了一倍。实验结果表明,2种并行检测方法不仅能够成倍加快检测速度,而且更适用于用户对内存的检测。     

单片机系统中的LED显示译码驱动电路

LED显示在单片机系统中应用广泛,它能够直观地向人报告系统运行状态与结果.论述单片机应用系统中LED显示译码驱动电路的几种实现方案,比较每种方案各自的优缺点,着重介绍了专用显示驱动芯片MAX7219的工作原理与应用方法,指出专用译码驱动芯片在单片机系统显示应用中的广阔前景.     

基于打印机的硒鼓芯片批量检测装置

针对当前打印耗材生产厂家硒鼓生产过程中需对采购硒鼓芯片进行检测的问题,设计了一种基于打印机的硒鼓芯片批量检测装置。该装置利用打印机上电自检过程来实现对同一型号10个硒鼓芯片单元的批量检测,具有检测速度快,易于操作的优点。