NiAl表面能的分子动力学计算

利用嵌入原子类型的势函数，通过分子动力学方法计算了Ｂ２结构标准化计量比ＮｉＡｌ合金的四个低指数晶面在６种温度时的表面能。计算结果表明，表面能随温度的升高呈增加趋势；最密排面的表面能最低；一些表面在高温下发生了重构或成分偏析等表面反应，用类似方法计算了ｆｃｃ结构Ｎｉ的表面能，计算结果与已知实验研究基本一致。     

A study of the passive films on chromium by capacitance measurement

Using capacitance measurement and Mott-Schottky analysis, the semiconducting properties of passive films formed on chromium within the passive potential range under different conditions were investigated. The study reveals a p-type behavior of the passive layers. Two semiconductive parameters, i.e., the acceptor density (N_A) and the flatband potential (E_FB), which are mainly related to composition and surface charges of the passive films, have been measured. The effect of film formation potential, passivation time, pH and composition of solutions on the parameters are discussed. N_A increases either with lowering film formation potentials or with prolonging passivation times. This is attributed to the transformation of a less hydrated oxide film into a more hydrated form. The changes of E_FB are discussed as a function of adsorptive anions and pH values of electrolyte solution.     

Agro-ecosystem modeling can aid in the optimization of biomass feedstock supply

Recent European Directives promoted the development of biofuels, requesting mandatory limits to their emissions ot greenhouse gases (GHG). Second-generation biofuels based on lignocellulosic biomass are prime candidates but their GHG emissions are variable and uncertain. Agro-ecosystem modeling can capture them and the performance of biofuel feedstocks.This study aimed at optimizing feedstock supply for a bioethanol unit in France, from agricultural residues, annual and perennial crops. Their productivity and environmental impacts were modelled on a regional scale using geo-referenced data on soil properties, crop management, land-use and future weather data. Several supply scenarios were tested. Cereal straw was the most efficient feedstock but had a low availability, and only miscanthus could meet the bioethanol plant's demand. Sorghum combined poor yields and high GHG emissions compared by miscanthus and triticale. A mix of three biomass sources used less than 3% of the regional agricultural land while abating GHG emissions by 60%.     

势能增氧生态净化工艺在高浓度有机废水处理中的应用

比较污水处理好氧工艺生物转盘法和滴滤池法的优缺点,并结合两种废水处理方法的优点,设计新的工艺——势能增氧生态净化工艺,对南京市腊梅食品厂高浓度有机废水进行处理。结果表明,势能增氧生态净化工艺设计简单,不需鼓风曝气,污水进入废水处理系统后出水即达到所要求的水质标准,且全部自控管理,具有废水处理效果佳、运行费用低的特点。     

以水功能区为基本单元的流域水资源配置方法探讨

以水功能区为基本单元,以水功能区管理办法和分水协议为基础,以滦河流域为研究对象,综合考虑上下游工农业用水和生态环境用水,对各水功能区的水资源潜在利用量和实际可利用量确定方法进行分析,探讨滦河流域水资源配置和合理利用方案,为水资源的合理开发利用提供参考依据。     

Study on Robot Path Planning Based on an Improved Artificial Potential Field Method

The method of artificial potential field has obvious advantages among the robot path planning methods including simple structure, small amount of calculation and relatively mature in theory. This paper puts forward the ＂Integral method＂ focusing on solving the problem of local minimization. The method analyses the distribution of obstructions in a given environment and regards adjacent obstacles as a whole, By changing the parameters of the repulsive force field, robots can quickly get out of the minimum point and move to the target point. This paper uses the Simurosot platform to carry on the simulation experiment on the improved artificial potential field method, which projects a feasible path successfully and verifies this method.     

The vulnerability of structures to unforeseen events

A structure is vulnerable to an unforeseen event if it is not sufficiently robust. One insight into the lack of robustness is gained through the vulnerability of a structure to disproportionate collapse. In this paper, the importance of assessing the vulnerability of a structure to unforeseen events is highlighted and the nature of unforeseen events examined. A theory of structural vulnerability which examines the form of the structure to determine the most vulnerable sequence of failure events is briefly described. The potential for damage to propagate through a structure is examined through a new measure of hazard potential and vertical pushover analysis. An analysis of an example structure shows that such an approach is able to capture the weaknesses in a structure either due to form or external actions.     

图像欧氏距离在人脸识别中的应用研究

图像欧氏距离可以嵌入到许多传统的图像分类识别算法中,该嵌入是通过对原始图像的线性变换来实现的,给出了一种基于数据场的图像线性变换方法,将其应用到图像欧氏距离中.实验结果表明,基于数据场的线性变换方法是一种可行的图像线性变换方法,该方法可以完成大尺度图像的线性变换,方便地将图像欧氏距离嵌入到传统人脸识别算法中.     

基于纳米银修饰电极的电位型铬（Ⅵ）传感器研究

纳米银修饰过的石墨电极在铬酸盐溶液中活化处理后,可制成一种新型的电位型铬传感器。将该传感器用于铬（Ⅵ）的测定,实验结果表明：此传感器对铬（Ⅵ）具有灵敏的电位响应,其线性范围较宽,为1．0×10^-7～1．0×10^-2mol·L^-1,检出限为4×10^-8mol·L^-1。应用于水样中铬（Ⅵ）的测定,结果符合分析要求。     

A Y-channel design for improving zeta potential and surface conductivity measurements using the current monitoring method

This study presents a new Y-channel design for measuring the zeta potential and surface conductance of a solid-liquid pairing using the current monitoring technique. The new design improves the throughput and reliability of the testing apparatus since the displacement between two solutions can be repeated many times without interfering with the experiments. It also increases the accuracy of the measurement by producing sharper start and end transitions for the current–time plot of the solution displacement process. In this design, efforts have been made to minimize the effects of electrolysis, Joule heating and undesired pressure driven flow on the measurements. An improvement on the current–time slope analysis is also presented. The Y-channel design was validated by comparing zeta potential measurements to published results. The zeta potential of several biological buffers relevant to the microfluidic community in plasma treated PDMS/PDMS and PDMS/Glass microchannels are presented. Preliminary studies of surface conductivity measurements using the Y-channel design were also conducted and are briefly discussed.