中药多糖的提取、分离纯化及其含量测定方法概述

近几年多糖备受关注,本文详细介绍了中药多糖的提取、分离纯化及其含量测定的各种方法。     

空调器CCC认证中常见不合格结构概述

笔者以CCC强制性认证安全标准为依据,总结了目前空调器产品检测中常见的不合格结构,并从不合格标准条款、不合格情形及改进措施3方面进行具体分析。为空调企业改进产品质量与提高产品安全性提供参考借鉴。     

农产品中苯氧羧酸类除草剂残留测定方法标准研究概述

今年是“质量和安全年”,食品质量和安全已成为全球关注的热点,特别是农产品和食品中有毒有害农兽药残留污染、食品中非法物质的添加和滥用、食品包装接触材料中有害物质的迁移等,更加成为食品安全关注的焦点。为配合国家质检总局“质量和安全年”的中心工作,本刊与安徽国家农业标准化与监测中心、国家农副加工食品质量监督检验中心联合组织“农产品风险预警专栏”,对农产品中苯氧羧酸类除草剂残留测定方法标准、坚果及炒货中抗氧化剂测定方法标准进行了详细解读;对气相色谱质谱法测定复合食品包装袋中二氨基甲苯进行了深入研究;对食品接触材料安全性现状和发展趋势以及我国纸杯产品的标准与质量安全进行了探讨和展望,旨在解决我国农产品安全问题,保护消费者的人身安全,提高我国农药残留检测水平,建立灵敏、有效、高通量的农药多残留检测技术。     

麻醉呼吸机通气原理概述及常见漏气故障的排除

本文主要针对麻醉呼吸机气路流向和借助于机器上相关开关排除漏气故障.     

化学检测中常见的SERS基底及未来发展方向概述

表面增强拉曼散射(Surface Enhanced Raman Scattering,SERS)技术,相对于传统的拉曼光谱具有选择性好、前处理简单和抗干扰能力强的特点,而且极大地提高了检测灵敏度.经过近二十年的发展,该技术己广泛应用于化学、环境科学和生物医学等众多领域.SERS技术的根本是有效地放大被测物质的拉曼信号,...     

臭氧及臭氧产品的应用前景

上海市最近提出世博环境保障计划,我们特地为此准备连续二期发表介绍环保产品的文章。     

VOC测定方法探讨

本文论述了涂料、胶黏剂中VOC测定的不同方法,通过气相色谱法分离,使消费者、检测人员及生产厂家对有害物质的成分一目了然,可以从源头上把好质量关,还大家一个健康的生活环境。     

臭氧老化箱臭氧气体浓度不确定度评定分析

以青岛市计量技术研究院自编方法ZJJ-YX-01《臭氧老化箱检测规范》为基础,以测量范围在(0～500)×10-6(摩尔分数)的臭氧老化箱为例,分析了臭氧气体浓度的不确定度分量的来源,并对其示值误差的不确定度进行了评定.     

医用臭氧消毒柜测试方法

本文对医用臭氧消毒柜进行计量性能评价,提出了测试方法。     

臭氧与室内空气品质

近一个世纪来,有关臭氧在室内应用引起很大的争议,但是大部分资料对臭氧的评价缺乏证实和可靠的科学依据。本文援引美国环境保护局(EPA)“被当做空气净化器销售的臭氧发生器(Ozone Generators thatare Sold as Air Cleaners)”一文的主要观点,介绍了臭氧对人体健康的影响、以及使用臭氧发生器的诸多弊端。     

茶叶中维生素分析方法概述

在查阅1907年以来国内外所有关于茶叶维生素分析方法研究文献的基础上,该文介绍了茶叶中的维生素及其分析方法现状,对脂溶性维生素和水溶性维生素的主要分析方法进行了系统地阐述,对微生物法、分光光度法、荧光法、高效液相色谱法、毛细管电泳法和流动注射化学发光法等主要分析方法进行了评述,并提出了应建立对茶叶中维生素的测定方法.     

Comparative analysis of the methods for SADT determination

The self-accelerating decomposition temperature (SADT) is an important parameter that characterizes thermal safety at transport of self-reactive substances. A great many articles were published focusing on various methodological aspects of SADT determination. Nevertheless there remain several serious problems that require further analysis and solution. Some of them are considered in the paper. Firstly four methods suggested by the United Nations "Recommendations on the Transport of Dangerous Goods" (TDG) are surveyed in order to reveal their features and limitations. The inconsistency between two definitions of SADT is discussed afterwards. One definition is the basis for the US SADT test and the heat accumulation storage test (Dewar test), another one is used when the Adiabatic storage test or the Isothermal storage test are applied. It is shown that this inconsistency may result in getting different and, in some cases, unsafe estimates of SADT. Then the applicability of the Dewar test for determination of SADT for solids is considered. It is shown that this test can be restrictedly applied for solids provided that the appropriate scale-up procedure is available. The advanced method based on the theory of regular cooling mode is proposed, which ensures more reliable results of the Dewar test application. The last part of the paper demonstrates how the kinetics-based simulation method helps in evaluation of SADT in those complex but practical cases (in particular, stack of packagings) when neither of the methods recommended by TDG can be used.     

真空冷冻干燥残余水分监测方法概述

通过残余水分含量来判断真空冷冻干燥过程中升华干燥和解吸干燥结束点是一种直接的方法。对当今残余水分监测的方法进行总结和分析,认为湿度传感器法和介电法将成为未来的一个研究方向,而称重法若能解决传热及安装等问题,也会是一种理想的测量手段。     

Coulometric methods for uranium and plutonium determination

Data on coulometric methods for U and Pu determination in various nuclear materials are presented, analyzed, and summarized. Coulometric determination methods at controlled current and controlled potential are considered. The main principles of the U and Pu determination procedures based on the use of the UO₂ ²⁺/U⁴⁺, Pu⁴⁺/Pu³⁺, and PuO₂ ²⁺/Pu⁴⁺ redox couples are presented. Various methodical factors influencing the error of the U and Pu determination, such as sample weight; supporting electrolyte composition; oxidation and reduction potentials; current; electrode material, shape, and activation procedure; impurity elements, etc., are discussed. Procedures for joint coulometric determination of U and Pu are considered separately. The main methods used by the authors for eliminating the mutual effect of U and Pu in their joint determination are described.     

EPS及其测定方法分析

膜污染问题一直是限制MBR(Membrane Bio-Reactor,膜生物反应器)发展和应用的一个瓶颈,而EPS(Extracellular Polymeric Substance,胞外聚合物)则被认为是MBR膜污染中的优先污染物.文中概括地介绍了EPS的类型、空间结构、对活性污泥特性的影响以及其与膜污染的关系,并对MBR中EPS提取及分析方法进行了综述,以期更全面的认识EPS特性,对实际运行的MBR工艺研究及膜污染控制等提供一定的理论依据.     

Three iterative methods for the numerical determination of stress intensity factors

Three iterative methods for the numerical determination of stress intensity factors at crack tips (by using the method of singular integral equations with Cauchy-type kernels) are proposed. These methods are based on the Neumann iterative method for the solution of Fredholm integral equations of the second kind. Two of these methods are essentially used for the solution of the system of linear algebraic equations to which the singular integral equation is reduced when the direct Lobatto-Chebyshev method is used for its approximate solution, whereas the third method is a generalization of the first two and is related directly to the singular integral equation to be solved. The proposed methods are useful for the determination of stress intensity factors at crack tips. Some numerical results obtained in a crack problem show the effectiveness of all three methods.     

Non-steady-state methods for determination of thermophysical characteristics of solids

A brief analysis is presented of the process of linearization of the mathematical thermal conductivity model for determination of thermophysical characteristics by non-steady-state methods (flash and constant velocity methods).Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 46, No. 5, pp. 769–773, May, 1984.     

Fluorescence methods for determination of temperature in fuel sprays

Fluorescent additives which allow the determination of droplet temperatures in hydrocarbon fuel sprays have been developed. These systems, which exploit the chemistry of organic exciplexes; should make possible the determination of droplet temperatures within 1 degree C. Two specific systems are described: 3,10-dicyanophenanthrene/diethylaniline over the 20-135 degrees C range, and naphthalene/tetramethyl-p-phenylene diamine over the 140-265 degrees C range. These additives should allow 2-D real-time nonintrusive visualization of the droplet temperatures in an evolving fuel spray.     

Three polarization reflectometry methods for determination of optical anisotropy

Three novel methods for the determination of optical anisotropy are proposed and tested. The first, the special points method, may be applied to any uniaxially anisotropic medium and is based on the measurement of s- and p-polarized light reflectances under near-normal or grazing angles (or both) and of the Brewster angle. The second method is based on the use of the Azzam universal relationship between the Fresnel s- and p-reflection coefficients. For a flat surface and an isotropic medium, the Azzam combination of coefficients becomes zero and thus is independent of the incidence angle, whereas for a uniaxial or biaxial anisotropic sample it acquires a certain angular dependence, which may be used to determine the anisotropy of the sample. Finally, for those cases in which the anisotropy of the material of a film deposited on an isotropic substrate is itself of interest, a third method, the interference method, is suggested. This technique makes use of the different dependences of s- and p-polarized beam optical path-length changes on the variation of the angle of incidence.