A new process of fabricating inverted-staggered tri-layer thin-filmtransistors

A new method of fabricating a-Si:H TFT with etching-stop structure has been proposed. Only one plasma-enhanced chemical vapor deposition is required in this new method and a PH₃/H₂ plasma treatment during the deposition has been used to form the TFT contact and thus saved another plasma deposition. With this method, a TFT of 500 Å active layer has been fabricated successfully. The drain current and saturation mobility of this device is 2.4×10^-7 A and 0.1 cm²/V sec, respectively, which is comparable to the conventional fabricating method. The plasma treatment will also form an additional leakage path on the TFT top surface and increase the TFT subthreshold slope. However, a current of less than 1 pA at V_G=-2.4 V can still be obtained. The possible mechanism of the contact formation by the plasma treatment is also discussed     

Robust controller with disturbance rejection for hydraulic servosystems

A controller is presented that improves the performance and reduces the sensitivity of hydraulic servo systems in the presence of parameter variations, nonlinear effects, and other disturbances. The control system has enhanced closed-loop stability and can recover from steady-state and transient error quickly and completely. It consists of a servo controller, an auxiliary controller, and a robust controller. Simulation and experimental results demonstrate the validity of the controller     

Laser glazing of an Fe-C-Sn alloy

Morphology and geometry of melted zones, cooling rates, microstructure and microhardness in the laser-glazed Fe-4%C-10%Sn alloy have been investigated. The computer simulation on the basis of the moving gaussian source model was used successfully to predict the maximum width and depth of the melted zone and the cooling rate. The microstructure from the surface to the bottom of the laser-melted zone is a non-crystalline phase, dendritic grains and a microcrystalline zone successively. Values of the averaged-spacing of the non-crystalline phase are 0.205⁶ and 0.121⁹nm, respectively; twinned martensites, having an axial ratioc/a of 1.128, existed in dendritic grains, and carbides of Fe₃ C at the interdendritic regions; the microcrystalline zone was composed of -Fe and a new bet (a=0.415 nm,c=0.955 nm) phase. The different microstructure in the melted zone can be explained by the results of the heat flow calculation. A fine eutectic structure (-Fe + Fe₃C) was observed in heat-affected zones. Microhardness of the eutectic structure can be predicted by the empirical relation of fracture stress to the interlamellar spacing of pearlite.     

A study on bioglass ceramics in the Na2O-CaO-SiO2-P2O5 system

A new bioglass ceramic with composition of Na₂O 12%, CaO 28%, P₂O₅ 10% and SiO₂ 50% with a high bending strength (120–140 MPa) and compressive strength (600–750 MPa) was studied. The crystallized phases of-Ca₂P₂P₇ and Na₂Ca₃Si₆O₁₆ were determined by X-ray diffraction. Optical microscopy of the material revealed that a very uniform crystal size of about 30 m was obtained with high nucleation frequency. The nucleation and crystallization processes were also investigated. The rat shoulder test showed that the material formed a tight chemical bond with biological texture and had good biocompatibility.     

Optically pumped submillimeter gas lasers and the prospects for constructing space-qualifiable LO systems

An optically pumped submillimeter laser operating in the 500 μm (600 GHz) to 100 μm (3 THz) spectral range is the primary and, at present, the only available local oscillator (LO) source for laboratory and astronomical heterodyne applications for this wavelength region. A short review of the state-of-the-art of submillimeter lasers as LO sources, with an emphasis given to receiver systems designed for airborne heterodyne observations, will be presented. The characteristics and prospects for constructing a spacequalifiable laser LO system will also be given.     

Pd/Mg(OH)2 Heterogeneous Nanocatalysts Synthesized by a Facile One-Pot Hydrothermal Method for CO Direct Esterification to Dimethyl Oxalate

Catalysis Letters - Pd-based heterogeneous nanocatalysts have wide application in chemical industry. However, the traditional synthesis process contains multi-steps such as impregnation, dry,...     

Morphology of conducting polymeric coatings: quantitative comparison between theory and experiment

The density profile of electrosynthesized polymeric layers on carbon fibers is obtained from gravimetric and scanning electron microscopy (SEM) data. The coating density ρ is found to decrease with increasing radial distance, r, subject to the power law . Based on a modified diffusion-limited aggregation (DLA) model, it is shown that lattice Monte Carlo simulation of the coating process predicts the experimentally observed power law exponent.     

基于iebook的电子书播放外部视频功能的实现

Exe类型电子书制作软件集成文字内容和小图片非常容易,效果也很不错,但是对集成高品质的音视频、数码照片等大容量数据文件却无能为力。通过对iebook超级精灵自带模板以及Exe电子书文件的深入分析,把flash技术、流媒体对象和file协议有机结合,实现动态加载指定相对路径下的外部视频文件到电子书中,大大提高了iebook超级精灵在处理多媒体方面的实用性。     

Effect of incipient removal of hydrogen through palladium membrane on the conversion of methane steam reforming: Experimental and modeling

This paper presents a mathematical model based on the reaction rate expressions to describe the displacement of methane conversion in the steam reforming. The effect of several parameters including weight hourly space velocity (WHSV), load-to-surface ratio, reaction pressure, hydrogen partial pressure in permeate side and reaction temperature were investigated. Simulation and experimental results showed that a conversion higher than 80% could be achieved in a palladium membrane reactor at reaction temperature of 500 °C relative to 850 °C in a conventional fixed bed reactor (FBR). Besides, the yield of CO (<2%) in membrane reactor was much lower than that (>50%) in the FBR, which indicated the significant depression of CO production in use of membrane reactor.