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X射线荧光光谱中影响理论计算相对强度的主要因素 总被引:1,自引:0,他引:1
提高理论相对强度计算准确度对X射线荧光定量分析及基体效应的数学校正至关重要。本文对X射线荧光光谱中影响理论计算相对强度的几种主要因素进行了探讨。考察了谱仪几何因子的不准确性对理论相对强度的影响,用三种不同来源的X光管原级谱强度分布计算和比较了一系列谱线的相对强度,通过详细考察发现不同作者发表的质量吸收系数之间及其与实测值之间在三个区域存在显著差异,并比较了用四种常用质量吸收系数算法计算的一系列谱线的相对强度,根据不同作者的激发因子算法编制了相应的计算机程序,对K~α,L~α和M~α的激发因子考察了它们之间的差异。 相似文献
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串联质谱中子离子相对强度稳定性的研究 总被引:2,自引:0,他引:2
采用串联质谱的多反应监测模式,在最佳碰撞能量条件下,监测同一物质的4对母-子离子对,计算不同子离子的相对强度,并比较了该值在甲醇标准溶液与血清基质中的差异.实验结果表明,在不同浓度条件下,5种代表生物碱的子离子相对强度的相对标准偏差小于6%,血清基质与甲醇标准溶液之间的相对偏差小于4.5%,这说明在最佳碰撞能量条件下,同一物质子离子相对强度与待测物的浓度和所处基质无直接关系.同时发现,在最佳碰撞能量条件下,子离子相对强度具有稳定性,这为复杂基质中的快速定性提供了可能性. 相似文献
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在恒定丙三醇质量分数x=0.1的条件下,测定了无液接电池(A)和电池(B)的电动势根据电池(A)电动势确定了丙三醇和水混合溶剂中的Ag-AgCl电极的标准电极电势,讨论了HCl的迁移性质;由电池(B)测得的电动势计算了HCl在该体系中的活度系数γA,计算的结果表明,对于所讨论的体系,在溶液中总离子强度保持恒定,HCl的活度系数服从Harned规则.在溶液组成恒定时,IgγA是温度倒数1/T的线性函数,讨论了混合物中HCl的相对偏摩尔焓及介质效应. 相似文献
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基于荧光激发光谱和发射光谱对波长呈高斯分布的设定,本文推导出固定波长同步荧光光谱峰峰值位置、相对强度和半峰宽度等3个主要光谱参数的理论计算式。所提出的计算式应用于若干荧光物质光谱参数的计算,并和实测值、文献计算值作了对照。结果表明,和文献计算方法相比,本法与所研究物质的实际光谱参数较为接近,可为固定波长同步荧光光谱参数的理论计算提供一有效方法。 相似文献
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测量了高氯酸钦(Ⅲ)和双(苯基亚砜)丙烷、双(苯基亚砜)丁烷配合物的溶液(甲醇-氯仿,二甲基甲酰胺)的电子光谱,计算了f-f跃迁的振子强度和强度参数,并讨论了“超灵敏”跃迁的强度和强度多数与配体性质的关系和溶剂的影响。 相似文献
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Rolf W. Saalfrank Norbert Löw Bernhard Demleitner Dietmar Stalke Markus Teichert 《Chemistry (Weinheim an der Bergstrasse, Germany)》1998,4(7):1305-1311
Efficacious metal control of self-assembly of dialkylketipinate dianions leads to completely different supramolecular assemblies. The structures of grid 1 , double-decker 2 , triple-decker 3 , and metalla-spherand 4 were characterized by X-ray crystallographic analyses or by NMR spectroscopy. 相似文献
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James J. P. Stewart 《Journal of computational chemistry》1991,12(3):320-341
Using a recently developed procedure for optimizing parameters for semiempirical methods,1 PM3 has been extended to a total of 28 elements. Average ΔHf errors for the newly parameterized elements are Be: 8.6, Mg: 8.4, Zn: 5.8, Ga: 14.9, Ge: 11.4, As: 8.5, Se: 11.1, Cd: 2.6, In: 11.3, Sn: 9.0, Sb: 13.7, Te: 11.3, Hg: 6.8, Tl: 6.5, Pb: 7.4, and Bi: 10.9 kcal/mol. For some elements the paucity of data has resulted in a method, which, while highly accurate, is likely to be only poorly predictive. 相似文献
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《Physics and Chemistry of Liquids》2012,50(5):564-573
Four analytical correlations based on the use of the corresponding states principle were used to calculate the enthalpy of vapourisation of fluids. Three of these correlations require as inputs the critical temperature and the acentric factor. The fourth requires a molecular Lennard–Jones parameter and the acentric factor. Results for 184 polar and non-polar fluids grouped into 9 families are compared with the values accepted by the Design Institute for Physical Property (DIPPR) project. Recommendations are given for the use of each model and for the choice of the adequate model for each family of fluids. 相似文献
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猪胰脏中铁钙镁铜铅锌镉锰钴镍的测定 总被引:2,自引:0,他引:2
采用硝酸-过氧化氢在自动回流消化仪中消化猪胰脏,火焰原子吸收光度法测定铁、钙、镁、铜、锌、铅、镉、锰、钴、镍的含量。,方法简便,快速,结果令人满意,并对猪胰脏食用价值进行了评价。 相似文献
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目的:建立化妆品中铍、镉、铊、铬、砷、碲、钕、铅8种有害元素的测定方法。方法:采用电感耦合等离子体质谱法,样品采用微波消解,以钇、锂、铟、铋为内标作定量分析。结果:各元素和内标元素在一定浓度范围内的质量数比值均与浓度呈良好的线性关系,线性方程的相关系数均大于0.9998,平均回收率为95%~104%,相对标准偏差(RSD)均小于3%。结论:该方法灵敏度高,准确,可为化妆品中上述元素的限量检查提供参考。 相似文献
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A thin-layer chromatographic method is reported for the separation of aldrin (or chlordane), dieldrin, γ-hexachlorocyclohexane, malathion, ethyl-parathion, and pentachlorophenol from each other. The procedure, however, does not separate aldrin and chlordane from each other although it does separate either pesticide from the other components. The method employs alumina plates with n-hexane:xylene:benzene:toluene:cyclohexane:methyl cyclohexane (50:50:50:50:50:50:) as developing solvent. 相似文献
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The enthalpies of dilution of aqueous solutions of formamide, acetamide, propionamide,N,N-dimethylformamide, and sucrose have been measured from about 0.15 to 2.0 moles-kg
–1
at 25.0°C. The results of the enthalpy measurements were used to calculate the pairwise enthalpies of interaction for each compound with itself. The equation of Savage and Wood together with their interaction parameters are used to predict the experimental results. All of the predictions are within the standard deviation of the original correlation of Savage and Wood (±220 J-kg-mole
–2
). Detailed examination of the results shows that specific effects are present but they are less than 220 J-kg-mole
–2
. Results on urea and substituted ureas are used to determine interaction coefficients for a urea group with itself and with another CH
2
group. The result,H
U,U
=–280 andH
U,CH
2
=29 J-kg-mole
–2
, is an improvement on the previous arbitrary assignment of parameters for urea interactions. 相似文献