共查询到20条相似文献,搜索用时 31 毫秒
1.
通过水质氯酸盐标准样品稳定性监测、均匀性检验及定值,介绍了氯酸盐标准样品的研制方法。研究结果表明,水质氯酸盐标准样品的均匀性和稳定性良好、定值方法可靠、量值准确,可用于环境监测和科学研究工作。 相似文献
2.
3.
4.
对新研制的水质钛标准样品进行了稳定性监测、均匀性检验及定值,确立了水质钛标准样品的制备、检验与定值程序.研究结果表明,新研制的水质钛标准样品的均匀性良好,至少在1年半的时间内稳定,定值方法可靠,量值准确. 相似文献
5.
对新研制的水质色度环境标准样品进行了稳定性检测、均匀性检验及定值,确立了水质色度环境标准样品的制备、检验与定值程序。研究结果表明,新研制的水质色度标准样品的均匀性良好,至少在两年的时间内稳定,定值方法可靠,量值准确。 相似文献
6.
7.
8.
X射线荧光光谱仪用水泥生料标准样品的研制 总被引:1,自引:0,他引:1
借鉴了普通标准样品制备技术 ,并根据X射线荧光光谱仪专用标准样品的特点 ,对系列标准样品化学成分的设计及配制方法 ,样品均匀性与稳定性检验 ,特性量值的定值方法与不确定度的样品的估计方法进行了系统的理论推导和实验研究 ,提出了采用高低两个端点样品配制中间样品的制样方法和通过测试高含量元素确定较低含量元素的定值方法 ,可使定值工作量显著减小。成功研制了11个生料(系列)标准样品 ,可用于校验X射线荧光光谱仪及其它以测量元素特征X射线为基础的分析仪器 ;采用熔融法制片可用作为量值传递 ;水泥及水泥熟料也可用本系列标样制作的标准曲线进行测定。 相似文献
9.
分子量大的氯代烃在气瓶内可能出现分层、沸点高的氯代烃可能在气瓶内吸附,从而引起挥发性氯代烃混合标准气体出现瓶内不均匀的现象。研究确定了氮气中22种挥发性氯代烃标准气体瓶内均匀性的实验方法,并通过考察量值随样品压力的变化来评价样品在瓶内的均匀性。根据实验结果分别计算了22种氯代烃瓶内不均匀性所引起的不确定度,结果显示在样品压力2 MPa时,1,1,2,2-四氯乙烷、间二氯苯、对二氯苯、邻二氯苯的量值显著变大,其瓶内不均匀性所引起的不确定度2%。样品压力2 MPa,22种挥发性氯代烃标准气体会出现不均匀现象,因此样品的最低使用压力为2 MPa。 相似文献
10.
11.
Repetitive DNA in humans is still widely considered to be meaningless, and variations within this part of the genome are generally considered to be harmless to the carrier. In contrast, for euchromatic variation, one becomes more careful in classifying inter-individual differences as meaningless and rather tends to see them as possible influencers of the so-called ‘genetic background’, being able to at least potentially influence disease susceptibilities. Here, the known ‘bad boys’ among repetitive DNAs are reviewed. Variable numbers of tandem repeats (VNTRs = micro- and minisatellites), small-scale repetitive elements (SSREs) and even chromosomal heteromorphisms (CHs) may therefore have direct or indirect influences on human diseases and susceptibilities. Summarizing this specific aspect here for the first time should contribute to stimulating more research on human repetitive DNA. It should also become clear that these kinds of studies must be done at all available levels of resolution, i.e., from the base pair to chromosomal level and, importantly, the epigenetic level, as well. 相似文献
12.
13.
常量元素与微量元素特征在物源分析中的应用 总被引:1,自引:0,他引:1
沉积物物源分析是研究盆地与造山带关系的重要途径。沉积物的地球化学特征在物源分析中起了非常重要的作用。通过查阅近几年相关文献资料,总结出常量元素与微量元素特征在沉积物物源分析中的主要应用:判断物源区的构造背景与判别沉积物源区物质组成等。地球化学是直观、简捷、实用、有效的分析方法之一。但沉积岩易受其它地质因素影响,在实际研究中,还需结合研究区的地质背景以及综合运用多种方法进行物源区分析。 相似文献
14.
《分离科学与技术》2012,47(11-12):911-925
Abstract Separation processes for the actinide elements are reviewed. The difference in oxidation states for the elements Th through Am provide the basis of their separation techniques. The transplutonium elements require multiplate chromatographic or extraction processes to separate them due to the small chemical differences of the common trivalent states. Ion-exchange and solvent extraction systems useful in laboratory tracer level separations and in multigram plant separations are described. 相似文献
15.
16.
17.
18.
随着社会的发展与进步,流行元素已经渗透到各种领域,陶瓷作品也不例外。当代一些流行元素在陶瓷作品中的介入,拓宽了设计者的设计思路,使得陶瓷作品更加出奇出新、各具特色,从而推动了陶瓷设计的革新和发展。 相似文献
19.
《分离科学与技术》2012,47(5):563-573
Abstract Steady-state and unsteady-state digital computer programs, processed on an IBM 7072 computer, were used to obtain the concentration profiles for hydrochloric acid, curium, americium, and europium for a 16-stage liquid-liquid extraction process which is the final purification step in the production of curium 244. The equilibrium data were in the form of empirical equations which were suitable for the computer solutions. The steady-state program, a trial-and-error procedure based on a mass balance and an equilibrium and efficiency condition written for each stage, was used to investigate the effect of changing the system variables on the separation. The unsteady-state program is based on mass balances and an equilibrium condition for each stage and was used to obtain the unsteady-state buildup of the transuranium concentration profiles for a step change in the transuranium feed concentrations. 相似文献
20.
The structure of glasses in the Li2O–B2O3–V2O5and ZnO–B2O3–V2O5systems of a high modifier content ([Li2O, ZnO]/[B2O3] ratio > 1) and 10 to 50 mol % V2O5are investigated by V-KEXAFS and Raman spectroscopy. In the glasses investigated, VO4tetrahedra are the predominant coordination polyhedra for the vanadium ions. The symmetry of the tetrahedra is more or less distorted in comparison with crystalline substances. The VO4tetrahedra can be either directly connected to each other or incorporated into the borate groupings of the BO3and BO4units. An increase in the vanadium content in the glasses reduces the interconnection of structural units and, therefore, the glass transition and crystallization temperatures. 相似文献