Pressure-induced non-bulk superconductivity in Eu1.2Mo6(S1−x Se x )8

High-pressure study has been made both resistively and magnetically on Eu_1.2Mo₆(S_1–x Se _x )₈. Superconductivity was detected at a lower pressure in samples forx0 than forx=0 in spite of the larger unit cell volume of the former. The superconductivity observed remains non-bulk up to 20 kbar. The maximum onset temperature of the superconductivity transition decreases withx.On leave from the Physics Institute, Chinese Academy of Sciences, Peking, China.     

An approximate nonlinear observer with polynomial coordinatetransformation maps

The state equivalence condition to the nonlinear observer form is stated in terms of the exactness of one-form. Using the definition of the approximate closedness, we relax the equivalence condition, thereby obtaining a necessary and sufficient condition for the approximate observer error linearizability. This approximate observer theory extends the realm of applications. Another great advantage of this approximation method is that the coordinate transformation is directly obtainable as vectors of polynomials, while it is, in general, not possible with the existing method,     

加速基因方法在最大流量频率曲线参数估计中的应用

基因方法是基于自然选择和自然基因机制的并行随机自适应工程模型参数全局优化估计的通用数值方法。它不限制模型结构、优化准则、被估参数的数目、约束条件等，已开始广泛用于各种工程模型的优化设计之中。文中对它的原理、步骤、特点进行初步探讨，并针对基因方法的弱点，作者提出予以改进的加速基因方法，后者在最大流量频率曲线参数估计中得到成功应用     

Electrostatic actuation of three-dimensional MEMS mirrors using sidewall electrodes

We propose and demonstrate electrostatic sidewall-electrodes actuation of three-dimensional (3-D) microelectromechanical systems (MEMS) gimbal mirrors. The linearity of the mirror angle dependence on actuation voltage is improved with the sidewall-electrodes actuation. In addition, the undesired spring-softening effect commonly found in electrostatic actuation, where the mirror resonance frequency decreases with increased tilt angle, is significantly reduced. Sidewall actuation enables superior performance of 3-D MEMS mirrors including large pull-in angles, reduced actuation voltages, improved device reliability, and fast switching times.     

Characterization of PdAg/Al2O3 composite membrane by electroless co-deposition

In this work, PdAg/Al₂O₃ composite membranes prepared by electroless co-deposition technique have been studied. Effects of plating time, Ag composition and total concentration of metal ions on surface morphologies, composition and microstructure of the resulting layers were investigated. Scanning electron microscope, energy dispersive spectrometer and nitrogen permeation technique were used to characterize the as-prepared composite membranes. From the experimental results, it shows that the surface morphology of the deposited PdAg layer is strongly affected by the Ag content of the plating bath. Since large differences of deposition rates and growth modes are observed between Pd and Ag grains, the PdAg layer exhibits the dendritic structure. As the Ag content is approximately 50%, the dendritic structured PdAg layer reveals the largest nitrogen permeability with the smallest size of residual pores. Furthermore, a comprehensive electrochemical analysis is proposed to interpret the composition and structure of the PdAg layer. Eventually, the experimental results are quite consistent with those predicted from the electrochemical analysis.     

Calculating the elastic moduli of steel-fiber reinforced concrete using a dedicated empirical formula

The equivalent inclusion method (EIM) is adopted to study the characteristics of the equivalent material properties of steel-fiber reinforced concrete as a function of the volume fraction and the length to diameter ratio of the fibers. It is found that the equivalent material moduli of concrete reinforce with randomly orientated and distributed fibers are insensitive to the length to diameter ratio of the steel fibers. A set of empirical formulae is then proposed for the purposes of engineering applications. The proposed empirical model can simplify the calculation of the equivalent material moduli. Verifications of the proposed empirical formulae with the EIM model and with experimental data are performed with two examples. The first is a compression test. The second is 4 point bending test. The empirical formulae, based on the equivalent inclusion method proposed in this study, represent an alternative means of quickly calculating the effective elastic modulus of steel-fiber reinforced concrete materials.     

A study on a generalized parametric interpolator with real-time jerk-limited acceleration

The impossibility of exact arc length computation for ‘standard’ parametric curves such as Bézier/B-spline curves makes it difficult to generate a feedrate profile with desired accelerations in real-time. This paper presents a new recursive trajectory generation method that estimates an admissible path increment and determines the initiation of the final deceleration stage according to the distance left to travel estimated at every sampling time, resulting in exact feedrate trajectory generation through jerk-limited acceleration profiles for the parametric curves. The proposed approach allows the feedrate profile to be dynamically adjusted according to geometrical path constraints for the curved path. The simulation result has been also provided to illustrate the generation of smooth feedrate profile encompassing a sequence of mixed NC blocks including traditional linear and circular blocks.     

基于虚拟仪器的差分功耗分析攻击平台

差分功耗分析攻击利用嵌入式加密系统功耗泄漏信号来获取加密系统密钥,将穷举问题转化为数据采集、处理问题.在对DES加密嵌入式系统攻击实验中,基于虚拟仪器的差分功耗分析平台令差分功耗分析攻击的数据采集过程由虚拟仪器应用程序控制进行,而后再对采集的功耗进行分析,能够快速、准确地找到加密系统密钥.较传统的穷举攻击而言,减少了消耗的时间和成本.     

纳滤回收染料废水中染料的实验研究

以含盐染料废水为研究对象,应用商业化的卷式膜组件,研究了纳滤膜对染料和盐的截留特性．实验结果表明,纳滤膜对染料的截留率高达99％以上．当染料分子量高于膜截留分子量时,染料初始浓度和染料品种对染料截留率的影响甚小,盐浓度对染料截留也无明显影响,但对NaCl截留率影响显著．随料液中NaCl浓度的增加,盐截留率快速下降,当盐浓度达到3．5％时,NaCl的截留率低于25％．纳滤膜对染料的高截留率和对NaCl的低截留率,使得应用纳滤技术从含盐染料废水中回收染料具有较好的经济性和可行性．