应用独立分量分析的激光测风雷达湍流频谱分解

针对大型风力发电机机组中常见的脉动湍流、风机尾流与涡流等湍流信号,研究了利用自然梯度下降的独立分量分析方法的湍流频谱分离效果,以区分中心风速与湍流信号,提高风机机组的综合工作效率。首先分析了风机组中常见湍流信号的后向散射与频谱分布特点,然后依据这些特点设计了对应的独立分量分析模型。在仿真结果符合要求的基础上,进行了双目激光雷达天线的风速采集与实际分离效果检测。实验结果表明,在大气折射率结构常数C2n≤10-14同时广义大气常数α≥4的通常情况下,利用双目信号能够分离出一个湍流中心和一个中心风速。对1 s内两个谱峰的波动范围进行统计,获得(2.59±0.05)MHz的中心风速以及(1.22±0.19)MHz的湍流中心估计,且二者的平均信噪比分别为25.93 dB和31.01 dB,能够在获得稳定的中心风速估计的同时得到一个较为稳定的湍流中心估计。     

Failure of high power varistor ceramic components

Ceramic varistors are electronic components which have a sharp change (over several orders of magnitude) of their electrical resistance at a well-defined voltage (switching voltage). Starting at low voltages, the resistance is large. But by exceeding the switching voltage the resistance drops dramatically and the component acts as a good conductor. Mounted parallel to a consumer, they are used as protection devices against over voltage loading. In the technical routine yearly billions of varistors are used to protect power lines, transformation stations, electronic devices, microelectronic systems or even LEDs.In service large temperature differences may come into existence, which cause severe mechanical stresses that even may destroy the components. The basic principles of the varistor behaviour are explained and examples of mechanical failure are discussed.     

A lightweight approach to component-level exception mechanism for robust android apps

Recent researches have reported that Android programs are vulnerable to unexpected exceptions. One reason is that the current design of Android platform solely depends on Java exception mechanism, which is unaware of the component-based structure of Android programs. This paper proposes a component-level exception mechanism for programmers to build robust Android programs with. With the mechanism, they can define an intra-component handler for each component to recover from exceptions, and they can propagate uncaught exceptions to caller component along the reverse of component activation flow. Theoretically, we have formalized an Android semantics with exceptions to prove the robustness property of the mechanism. In practice, we have implemented the mechanism with a domain-specific library that extends existing Android components. This lightweight approach does not demand the change of the Android platform. In our experiment with Android benchmark programs, the library is found to catch a number of runtime exceptions that would otherwise get the programs terminated abnormally. We also measure the overhead of using the library to show that it is very small. Our proposal is a new mechanism for defending Android programs from unexpected exceptions.     

Design and characterization of compact proton exchange membrane water electrolyzer for component evaluation test

In this study, we designed and developed a compact electrolyzer for the evaluation of components in proton exchange membrane (PEM) water electrolysis. First, this electrolyzer features a precise pressure-control system that controls the active electrode area and facilitates setting the desired clamping pressure. This mechanism makes it possible to optimize the electrolyzer performance. Second, it has two reference electrodes that are connected on the faces of the active electrode area of the anode and the cathode on the PEM. The polarizations at the anode and the cathode, the membrane resistivity, and the porous transport layer (PTL) overpotential were measured. The details of the design are described, and the electrochemical performance was measured. The optimized clamping pressure for this electrolyzer component was obtained as the specific value. A new measurement method was developed for estimating polarizations at the anode and the cathode, membrane resistance, and PTL overpotential using two reference electrodes.     

特大型煤矿企业工业场地地基优化分析

以某特大型煤矿企业工业场地为例，运用Ｒ—Ｑ因子分析方法，对场地地基进行骤类评判，优化分析地基条件，主动指导场地地面工艺设计。此种评价方法，对于国家在对工程项目进行投资评估时具有参考意义，同时对于建设单位指导场地地面大规模工程建设，控制用于地基处理巨大数额的投资同样具有重要的现实意义     

装药燃面分析的组件化技术

基于组件技术的装药燃面分析软件采用三层结构.其交互层定制用户界面;中间层处理用户请求及实现内部联接;主程序中调用图形、药柱、数据处理等组件功能接口,实现系统集成.药柱组件使用IDL定义接口及其属性与方法,编译后添加接口代码生成组件.图形组件以OpenGL函数为图形绘制支撑.数据处理组件处理计算产生的数据.存取数据选用SQL作为数据库.     

休闲社区--现代居住环境景观设计手法探讨

首先提出了休闲社区的概念，提倡一种更加质朴，自然，更加清新和追求不留设计痕迹的居住环境设计风格。继而从小区地形塑造，步道系统，社区广场，植栽配置，基础绿化，水景，消防车道等各个方面，针对目前国内社区在规划设计中存在的一些弊病，对现代居住环境景观设计手法进行探讨，提出了许多具有建设性，操作性强的方法。文中还着重提到，应在建筑，道路都还没有确定的情况下，由景观规划师来做整体规划，对小区建筑，道路进行整体布局，从而创造真正的社区，营造亲切的人性空间。     

园林景观中的自然要素

园林景观中的自然要素在不同国度、不同时代以及不同文化背景中的表现特征有着许多的共性,它们并不独立存在,而是相互依存在不同的景观内涵中.研究园林景观自然要素的表现,在共性中寻求不同的个性题材.适地适景,巧妙地组织与运用园林景观中的自然要素,展示出不同地域的设计风格.     

圆明园盛期物质实体空间构成要素分析——山水要素

对于圆明园整体空间结构的把握必须从要素的分析入手,尤其是作为园林基底的山水要素。理清圆明园实体空间中山水要素的组织和建构特色,不仅能够让读者更清晰地了解盛期圆明园的建设特色,而且可为目前圆明园遗址的保护整治提供可操作的依据。通过对圆明园相关史料的考证,结合圆明园遗址的现状,重点分析山体要素的类型、形态与尺度等,以及水体要素的水源、水闸、水位和流向、岸壁做法等。     

景观设计的人文要素概念初探

在了解人文概念的基础上，文章确立了景观设计的人文要素概念，以及景观设计概念与文明进程，并对其在景观设计中的地位和意义进行了阐明，进而理顺景观设计的人文要素与其他要素的关系是十分必要的。