化学需氧量(COD)测定仪示值误差测量不确定度评定

根据JJG 975—2002《化学需氧量(COD)测定仪检定规程》的检定方法,以符合规程的化学需氧量标准物质为标准器具,对化学需氧量(COD)测定仪的示值误差进行了不确定度评定分析。     

化学需氧量测定仪的测量结果不确定度评定

本文依据JJG 975-2002《化学需氧量(COD)测定仪检定规程》对化学需氧量(COD)测定仪的A类仪器温度示值误差及A类仪器示值误差进行不确定度评定。评定方法适用于检测化学需氧量(COD)测定仪的A类仪器温度示值误差及A类仪器示值误差的不确定度评定。     

化学需氧量(COD)测定仪校准结果不确定度评定

根据JJG975—2002《化学需氧量(COD)测定仪检定规程》的检定方法,以符合规程的化学需氧量标准物质及多点温度巡检仪为标准器具,对化学需氧量(COD)测定仪的示值误差及温度示值误差校准结果分别进行了不确定度评定分析。     

化学需氧量(COD)测定仪示值误差测得值不确定度的评定

依据JJG 975-2002《化学需氧量(COD)测定仪检定规程》及JJF 1059.1-2012《测量不确定度的评定与表示》对分光光度原理A类仪器及电化学原理B类仪器,按规程要求各校准点示值误差测得值不确定度进行了评定,评定过程真实有效,可为相关机构技术人员在检定/校准化学需氧量测定仪中评定示值误差测得值的不确定度提供参考.     

化学需氧量（COD）示值误差不确定度评定的分析

化学需氧量（COD）测定仪因测量原理不同分为A类、B类,两类仪器在检定规程中的COD示值误差计算方法不同,因此其不确定度评定方法也有所差异。本文对两类仪器COD示值误差的不确定度进行了详细的分析。分析结果：A类：Urel=4％（k=2）,B类：U=0．8mg／L（k=2）。     

化学需氧量溶液标准物质的定值及不确定度评定

采用重量-容量法,配制了化学需氧量溶液标准物质,利用一级标准物质进行比较定值,并对溶液标准物质进行了均匀性检验和稳定性考察。对定值的不确定度进行了评定。化学需氧量溶液标准物质的定值结果为2000mg/L,扩展不确定度为:Urel=2%,k=2。     

烘干法水分测定仪检定用氯化钠溶液标准物质

为满足烘干法水分测定仪检定和质量控制中的量值溯源,研制以氯化钠纯度标准物质为原料、质量浓度为5.00%的氯化钠溶液标准物质。该标准物质经检验证明其均匀性良好,在室温下可稳定保存12个月。其量值采用重量容量法确定,扩展不确定度为0.02%(k=2)。该标准物质经多家实验室采用多种原理的方法进行验证,证明其量值准确可靠,可作为量值传递的标准用于烘干法水分测定仪检定。     

化学需氧量(COD)测定仪检定装置的不确定度评定

本文介绍了化学需氧量(COD)测定仪检定装置的工作原理及组成,并对该装置的不确定度进行分析和评定。     

谷物标准水分样品的制备方法

谷物水分测定仪在量值传递和溯源上有着自身特点。通常情况下,计量标准或标准物质的量值是自上而下逐级量传到工作计量器具,而工作计量器具的量值是自下而上逐级溯源到计量基准或高等级标准物质。而谷物水分测定仪检定所用的计量标准(标准物质),依照JJG891-2005《电容法和电阻法谷物水分测定仪》检定规程要求,是由检定人员用当地原粮制备谷物标准水分样品,对谷物水分仪的示值误差进行检定。这就     

熔点测定仪示值误差测量结果不确定度评定

<正>一、概述1.依据JJG701-2008《熔点测定仪》检定规程。2.标准器国家标准物质。3.检定对象熔点仪。     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.     

聚苯胺及其复合物的制备和结构及形貌分析

通过化学氧化法分别制备盐酸,盐酸和十二烷基苯磺酸,碳纳米管(MWNTs-COOH)掺杂的聚苯胺,利用红外光谱,紫外光谱,扫描电子显微镜和透射电子显微镜对所制备聚苯胺的结构和形貌进行分析。分析不同掺杂物对聚苯胺的结构和形貌的影响;同时研究了超声波作用对聚苯胺形貌以及聚苯胺包裹MWNTs-COOH情况的影响。     

Thermodynamic similarity and prediction of the properties and characteristics of substances and processes

Principles of the theory of thermodynamic similarity are considered in application to all aggregate states of a substance, including phase transitions, and to the change in dissipative structures in open systems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 5, pp. 709–716, November, 1987.     

Modelling and computation of curing and damage of thermosets

The curing of thermosets is a complex process involving the transition from a fluid into a (visco-) elastic solid. This phase transition comes along with an increase in stiffness and a volume shrinkage of the polymer. The latter may lead to severe residual strains and stresses, which in turn can cause damage in the final, usually quasi-brittle material. In this contribution a constitutive model is developed which takes into account the curing of a thermosetting material together with the process-induced damage as resulting from curing shrinkage. The curing of the material is governed by a phenomenological hypoelastic constitutive equation which includes temporal evolutions for stiffness and volume shrinkage. Thermal and viscous effects are neglected in the present study. An isotropic gradient-enhanced damage model is adapted to describe the damage evolution. The curing-damage model is implemented into a finite element code and numerical examples for thermosetting materials demonstrate that the proposed model is capable to predict cure-induced damage in thermosets.     

Mechanisms of Corosion and Oxidation of Metals and Alloys

Selected topics in field of the study of the mechanisms of corrosion and of oxidation of metals or alloys are presented. The first part reports a new model for the mechanism of the breakaway oxidation of ferritic stainless steels in water vapour. The second part is devoted to the physico‐chemical aspects of oxidation and presents experimental methods useful in the kinetic modelling applied to two alloys, the zircalloy‐4 and an AlMg5 % in the liquid state. In the third part the physical and numerical modelling of the stress corrosion cracking behaviour in face‐centered cubic (fcc) alloys is detailed, which enables the study of the influence of macroscopic parameters (such as the temperature or hydrogen activity) on the fracture process.     

碳化硼陶瓷增韧补强和致密化研究现状及其展望

碳化硼陶瓷具有极高的硬度,然而其低韧性、低抗弯强度、难以致密化限制了它的广泛应用.已有一些研究集中于碳化硼陶瓷增韧补强和致密化,对这一方面国内外研究进展进行了归纳与评述,阐明各种增韧补强和致密化方法的优缺点,提出碳化硼陶瓷增韧补强和致密化研究值得发展的一些方向.     

Measurement and analysis of elastic and anelastic properties of alumina and silicon carbide

Measurements of dynamic Young's modulus, E, and damping as a function of temperature, T, were made for alumina and silicon carbide. The Young's modulus data were compared with some from the literature, and analysed in terms of a theoretical framework relating the Debye temperature, θD, with the elastic constants. For both materials this analysis yielded a ratio T₀/θ_D which was near 0.4, where T₀ is an empirical fitting constant for the plot of (E(0)−E)/T versus 1/T (E(0) is the value of E at 0 K). The analysis of the damping data in terms of an Arrhenius type dependence led to effective activation energies near kT, where k is Boltzmann's constant. This revised version was published online in November 2006 with corrections to the Cover Date.     

Preparation and characterization of phosphate and arsenate apatites of strontium and their solid solutions

Samples of phosphate and arsenate apatites of strontium and six of their solid solutions, spread over the entire compositional range, were prepared by a wet method. They were characterized by chemical, X-ray, electron microscopic and infrared analyses. The validity of Vegard's law established the homogeneity of the solid solutions.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。