Appearances of internal micro bubbling, multiple micro explosions, multiple micro jets and micro diffusion flames around an abruptly heated micro plastic-resin particle

Heating, gasifying and burning processes of a micro plastic-resin particle, which has a diameter of about 200 μm and is suddenly exposed to a hot oxidizing atmosphere, are observed and optically processed by combining a micro schlieren system with a high-speed CCD video camera. The following three devised approaches are introduced: the use of an oxidizing combustion gas downstream of a spark-ignited propane–air lean premixed flame as a sudden heat source, the use of a spherically reformed micro particle on a fine tungsten wire of 5 μm diameter, and the use of a simultaneous direct and schlieren optical system. The first technique realizes slow heating and enables a micro resin particle to undergo the same circumstances as those experienced by plastic-resin particles in the plastic-resin powder combustion. The second approach improves the accuracy and reproducibility of image processing, whereas the third optical system gives simultaneous pictures of the transparent visible image and the schlieren image around a micro resin particle of one heating process. The results show that there exists intense multiple internal bubbling, multiple micro explosions, multiple micro jets and micro diffusion flames, and that their existence exerts strong influences on gasification characteristics of a micro resin particle and results in a high burning rate constant.     

微纳加工技术在微纳电子器件领域的应用

微纳加工技术推动着集成电路不断缩小器件尺寸和提高集成度，光学光刻技术依然是目前的主流微纳加工技术，同时有多种替代技术如电子束直写、极紫外光刻和投影电子束技术，文章介绍了自上而下的微纳加工技术的进展及其在微纳器件研制的重要作用。     

基于微型光谱仪的微小型快速生化检测仪设计与实验

面向野外环境伤病员重要生命参数快速检测的需求,基于MOEMS技术和嵌入式技术,提出了一种基于连续光谱分析的微小型快速生化检测仪新结构。在研究检测对象和方法的基础上,成功研制出基于连续光谱分析的微小型快速生化检测仪原理样机;对样机的杂散光、吸光度线性度、吸光度重复性、稳定性、温度准确性进行了测试分析,各项指标均达到设计要求;通过临床测试初步实验,可实现钠离子、葡萄糖、血糖等多项重要生命参数的快速检测。     

Development of a double-sided micro lens array for micro laser projector application

This paper introduces the development of a double-sided micro lens array (DSMLA) for application in micro laser projectors. For commercial mass production, it is necessary to investigate the concurrent engineering of optical design, mold fabrication, and plastic injection molding at once. This experiment based the design of the micro lens array on the scalar diffraction theory. The proposed DSMLA can simultaneously shape red, green, and blue laser beams into a uniform projection pattern. An ultra precision diamond turning machine using a slow tool servo method fabricated the mold. The study considered optical design constraints from the feedback of mold fabrication and plastic injection molding, measuring and comparing fabricated samples with calculated results. Experimental results show that the fabricated DSMLAs achieve the desired function and application feasibility for micro laser projectors.     

Research on the resolution of micro stereo lithography

Micro stereo lithography is a kind of technology utilizing the solidified effect that photo curable polymer will appear under ultraviolet （UV） laser exposure. It is widely used in three-dimensional （3D） micro fabrication. We get the experimental values of a pair of UV laser curing coefficients, absorption coefficient and critical curing energy, of curable resin by fitting the calculation results of the Gaussian beam theory and experimental curing results. The theoretical relation between the curing unit＇s shape and the exposure features of time and intensity of convergent Gaussian beam is presented. The calculation and experimental results of curing unit under different conditions agree well with each other. This research offers a steady base for further research about the improvement of resolution.     

微型平板热管试验特性研究

设计了一套微型微槽道平板热管并进行了散热特性试验。试验表明:该结构热管在竖直、水平和倒立方向,其传热效果基本一致,均能实现有效散热;在小热流密度下,铜板与平板热管散热效果差异较小;当热流密度大于50W/cm2时,工作温度差异达到14℃,该温度随着热流密度增大显著提升,直至铜板不能工作;可见,在高热流密度下采用平板热管是很有必要的。     

Controlling the micro/nanostructure of self-cleaning polymer coating

Polypropylene bio-mimic self-cleaning surfaces with porous micro-nano-binary morphology structures were prepared by a simple casting method. The influence of the cooling process and solvent composition on water contact angle, sliding angles and self-cleaning properties has been investigated. Detailed SEM morphology studies revealed that the polymer used in this work is commercial-grade granular low-density polyethylene (LDPE) forms petal-like crystalline, which are of micrometer scale in length and nanometer scale in thickness. The nano-crystallines on the surface represent a porous three-dimensional micro-nano-binary structure. It was found that a compromise to the film porosity and crystal nano structure is essential for achieving a satisfied self-cleaning surface. Under optimum condition, a water contact angle of 152.2°, and a sliding angle of 1.7° can be obtained using this simple method.     

Thermodynamics of deformation of micro composites

A thermodynamic evaluation, based on simultaneous measurements of the mechanical work and the concomitant heat of deformation in a stretching micro calorimeter, was performed on polycarbonate/carbon fibre (PC/CF) micro composites. Single fibre composite specimens containing sized and unsized CF were subjected to different thermal treatments. Thermodynamic effects of deformation were measured for both elastic and plastic deformation ranges. In the elastic/beginning of plastic deformation ranges the internal energies and heat effects of deformation of micro composites exceeded those of matrices. The highest internal energy and, in turn, the highest fibre/matrix adhesion, was found in the case of the quenched micro composites with sized fibers. Thermodynamic effects of deformation and calculated material constants of PC were in reasonable agreement with data in the literature.     

Atom-optical elements on micro chips

We describe the realization of atom-optical elements as magnetic waveguide potentials, beam splitters and gravitational traps on a microchip. The microchip was produced by electroplating gold conductors on an aluminium-oxide substrate. The conductors are 30–150 μm wide and allow for the generation of waveguides at large distances to the chip surface, where surface effects are negligible. We show that these elements can be integrated on a single chip to achieve complex atom-optical circuits.     

Z箍缩丝阵负载微型装配系统

 在利用金属丝阵Z箍缩产生强X射线辐射的方法中,为获得超强X射线,一般采用直径几μm的钨丝构成单、双或多层圆柱面状丝阵负载,其中丝阵负载的结构和装配精度是关键因素。为制备出均匀、平直的丝阵负载,进行了Z箍缩丝阵负载微型装配系统的研制,建立了基于机器视觉、微力传感器和精密运动控制系统的Z箍缩丝阵负载微型装配实验系统。该系统成功实现了双层直径5 μm钨丝丝阵的装配,且张力控制精度达0.002 N。     

Thermometry by micro and nanodevices

In this paper we briefly discuss the current provisional temperature scale of 2000 (PLTS-2000) for low temperatures. Electronic thermometry is presented and discussed, focusing on its potential in verifying and realizing a future temperature scale. The discussion covers secondary thermometers such as NIS and SIS thermometers and noise, shot noise and Coulomb blockade primary thermometers. The last one is discussed in more detail.