Estimating surface evapotranspiration using combined MODIS and CBERS-02 data

Land surface evapotranspiration is one of the most important components in water cycle between earth and atmosphere, and plays a very important role in the atmosphere, hydrosphere, and biosphere of the planet. It is an urgent task to understand the evapotranspiration process over different surface types and conditions in agriculture, hydrogeology, forest, and ecology for the purpose of using water resources properly. Additionally, land surface evapotranspiration is a key parameter in the synop…     

A new family of windows — convolution windows and their applications

A new family of windows is constructed by convolutions via a few rectangular windows with same time width and is thus referred to as convolution windows. The expressions of the second-order up to the eighth-order convolution windows in both the time and frequency domains are derived. Their applications in high accuracy harmonic analysis of periodic signals are investigated. Comparisons between the proposed windows and some known windows with the same width shows that, when the synchronous deviation of data sampling is slight, the proposed ones have the least effect of spectral leakage. Therefore, the new windows are well suited for high accuracy harmonic analysis and parameter estimation for periodic signals. The error analysis and computer simulations show that the estimation errors, corresponding to frequency, amplitude and phase of every harmonic component of a signal, are proportional to the pth power of the relative frequency deviation in case of the pth-order convolution window is applied to windowing signal of approximately p cycles. By introducing real time adjustment in sampling interval, the proposed algorithm can adaptively trace signal frequency and lead to less sampling synchronous deviation. The proposed approach has the advantages of easy implementation and high measure precision and can be used in harmonic analysis of quasi-periodic signals whose fundamental frequency drifts slowly with time.     

齿轮成型磨削齿形误差在线测量技术

基于遗传算法并针对齿轮成型磨削加工问题，提出了一种齿轮齿形误差在线测量的方法，可以有效地解决测量起始点难于精确确定的问题，并能实现齿轮分度误差的补偿。计算机仿真和实际测量证明了方法的有效性。     

用精准管理提升炼铁系统运行质量

回顾了2005年1—4月炼铁系统所做的主要工作、主要技术经济指标完成情况和炼铁系统存在的主要问题；分析了当前及今后炼铁系统面临的形势和主要任务；提出了今后炼铁要做的重点管理和技术工作。     

ASME规范之材料篇(2004版)内容简析

主要介绍了ASME规范的内容、版本的变化情况,以及其材料篇中的材料标准与ASTM标准的关系,并针对2004版ASME规范第II卷A篇(铁基材料)中的主要变动情况做了归纳总结和分析,给出了纳入2004版ASME规范第II卷A篇的锅炉和压力容器用的一些新材料情况,和增加的新标准的主要内容。     

PDCA循环与贯彻ISO9001:2000版标准

从贯彻ISO9001:2000版标准角度,阐述如何将PDCA循环理论应用于组织实现质量体系从ISO9000:1994标准到ISO9001:2000标准的转换。     

国内管线钢标准应用现状分析

简要介绍了国内管线钢的组织分类及其特性要求,并对国内管线钢目前应用标准情况进行了分析研究。     

建筑材料中放射性核素限量标准的探讨

《建筑材料放射性核素限量》（GB6566—2001）结束了我国建材标准长期不统一的局面，规定了对建材中放射性实现强制检定的要求，但在装修材料分类、空心材料、废渣利用、测量方法等方面存在着一些不合理的规定。与以往的国家标准相比。对建材中的放射性控制明显放宽，甚至比原来的建材行业标准对石材的控制还要宽，影响了公众的辐射防护安全。对此进行了详细的分析和讨论。     

建筑材料放射性核素测量

详细叙述了采用NaI低本底多道γ谱仪测量建筑材料天然放射性核素镭、钍、钾放射性比活度的原理与方法。通过测量纯镭、纯钍、纯钾标准源，计算了谱仪对镭、钍、钾的响应系数。采用逐道最小二乘法分析建材样品中镭、钍、钾放射性比活度，运用以上方法对建材样品标准源进行测量，分析结果与标准数据之差在3％之内，远低于国标对测量不确定度的要求。     

放射性气体活度测量

研制了一套放射性气体活度测量装置及配套测量系统,研究考查了放射性气体活度测量装置及标准测量系统的性能和技术指标;实际测量了放射性气体活度并评定了其不确定度;对放射性气体活度测量系统量值传递技术进行了研究。整套装置技术指标满足有关标准、规范和规程要求,可作为工作标准对我院放射性进行常规测量、检定。