F2级砝码校准测量能力评定报告

本文详细介绍了F2级砝码校准结果的不确定度评定方法及校准能力验证方法.     

9F级联合循环供热机组停用保护系统设计技术方案研究

在火力发电厂中,主设备的腐蚀问题会带来重大安全隐患和经济损失。因此,电厂热力设备在停运期间采取适当的保养措施是非常重要的。针对9F级燃气-蒸汽联合循环供热机组中余热锅炉的水汽系统,制定了热风+气相缓蚀剂的停运防锈蚀联合保养方法,通过减少设备内部水分,通入带有保护性的气相缓蚀剂来达到保护热力设备的目的。阐述了停用保护系统设计、保养实施过程、保养装置运行操作,为燃机机组停用保护工作的有效实施提供必要的参考。实际应用的检验表明,该停用保护技术具有成本低廉、操作简单、保护高效等优点,对于启停频繁的燃机热力设备的维护和保养工作具有重要的指导意义。     

Advantages of a Combined System for Metering and Regulating Heat Consumption

Advantages are considered for a combined system for metering and regulating heat consumption, and data are given on the reduction in heat consumption without deterioration in conditions in such a system.     

光源相关色温计算方法的讨论

本从光源的色温及相关色温的定义出发,讨论了色温的三种计算方法。     

钠离子电池正极材料NaVPO4F的合成及其电化学性能

本文报道了在氩气保护下用两段高温固相反应法制备NaVPO4F作为钠离子电池正极材料,并用傅立叶红外光谱(FT-IR),原子吸收光谱(AAS),热重分析(TG/DTG),X-射线衍射(XRD),扫描电镜(SEM),恒流充放电等对其结构和性能进行了测试和表征.结果表明:750℃左右反应可以获得稳定、结晶度好的NaVPO4F,其晶型为简单单斜晶系,与前驱体VPO4的晶型一致;SEM测试表明NaVPO4F的粒径分布均匀,粒径大小在微米级,材料首次放电容量为87mAh/g.     

基于线热源模型结合参数估计计算岩土热物性方法探讨

介绍了地源热泵空调系统中基于线热源模型结合参数估计法下的4种岩土热物性计算方法,结合工程实例对比分析了这4种方法的计算结果。建议在实际工程中采用三参数估计法来计算岩土导热系数、钻孔内热阻和岩土容积比热容为妥。     

不同热输入下F460钢焊接粗晶热影响区韧脆转变的内在机理

使用Gleeble 3800热模拟试验机模拟F460钢单道次焊接条件下焊接粗晶热影响区的热循环过程,通过光镜(OM)、扫描电镜(SEM)分析热影响区的显微组织、确定临界事件,通过ABAQUS软件计算临界解理断裂应力σf,进而系统分析不同焊接热输入E下韧脆转变温度变化的内在机理。结果表明:随着E的提高,焊接粗晶热影响区显微组织依次为少量板条马氏体和大量细密的板条贝氏体,板条贝氏体较多的板条/粒状贝氏体,粒状贝氏体较多的板条/粒状贝氏体,粗大的粒状贝氏体。原始奥氏体晶粒、贝氏体团的最大尺寸随着E的提高而变大。在完全解理断裂的冲击断口上,寻找停留在缺口尖端附近的残留裂纹,通过对比残留裂纹长度、原始奥氏体晶粒大小、贝氏体团尺寸,发现不同E下解理断裂的临界事件尺寸都是贝氏体团大小,而临界事件尺寸越小,韧脆转变温度越低。此外,通过有限元模拟缺口尖端的应力分布得到σf,σf越大冲击韧度越好,随着E的提高σf降低,故进一步说明随着E的提高韧脆转变温度Tk上升的内在机理。     

The Development of a Standard for Contact Transient Methods of Measurement of Thermophysical Properties

Contact transient methods, some of which are available as commercial forms, are now widely used worldwide for thermal properties measurements on broad ranges of materials used in physical, chemical, and medical applications. However, in many cases the claimed measurement uncertainty has not been substantiated while in others – especially for the multiproperty techniques – internal inconsistencies in measured and/or derived values are clearly apparent. Following recommendations of participants of two workshops held on the subject in Würzburg (1999) and Cambridge, Massachussetts (2001), NPL agreed to coordinate a task to develop a standard test-method for these techniques. This involved using inputs provided by a small group of individuals from organizations in several European countries and also taking note of comments from other interested parties via the internet during the course of the development. Details are provided on the resulting document, which takes the form of a generic standard containing appropriate details and related information common to all techniques. These sections include the scope, theory, summaries of method, basic apparatus and experiment, the influencing factors, specimen requirements, procedure, and recommended approach for analysis of the experiment and calculation of the results. In addition, there are six annexes, each of which contains additional information that applies to a specific technique. Finally, the document proposes a recommended approach for verification of a technique together with a list of appropriate reference materials having known values for one or more properties. The status of intercomparison studies will also be reported. Paper presented as the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder.