土壤中总汞测量不确定度的评定

依据JJF1059-1999,对GB/T17136-1997冷原子吸收分光光度法测定土壤中总汞含量进行了不确定度评定。建立了数学模型,对各不确定度分量进行分析和量化。计算出土壤中总汞含量测量结果的相对合成标准不确定度为0.0215,扩展不确定度为0.163mg/kg。在土壤总汞含量测量过程中,求试液中汞含量贡献的不确定度最大。     

电感耦合等离子体发射光谱法测定食品中钙、镁、磷、铁、锌、锰含量的不确定度评定

采用电感耦合等离子体发射光谱法同时测定食品中钙、镁、磷、铁、锌、锰的含量,通过建立数学模型,对各不确定分量进行评估量化,计算合成不确定度和扩展不确定度。结果显示：当置信概率为95%,包含因子为2时,样品中钙含量为772 mg/kg时,其扩展不确定度为22 mg/kg;镁含量为269 mg/kg时,其扩展不确定度为14 mg/kg;磷含量为902 mg/kg时,其扩展不确定度为26 mg/kg;铁含量为13.0 mg/kg时,其扩展不确定度为0.62 mg/kg;锌含量为9.73mg/kg时,其扩展不确定度为0.38 mg/kg;锰含量为8.36 mg/kg时,其扩展不确定度为0.19 mg/kg。     

冷原子荧光法测定蔬菜中痕量汞的不确定度评定

对冷原子荧光法测定蔬菜中痕量汞的不确定度进行了评定。不确定度来源主要为配制标准工作溶液引入的不确定度,称取样品质量引入的不确定度,样品消化引入的不确定度,定容体积引入的不确定度,重复测定引入的不确定度。当蔬菜中汞含量为5.2μg/kg时,测量结果的扩展不确定度为0.50μg/kg。     

纺织品中五氯苯酚残留量测量不确定度评定

采用气相色谱法测定纺织品中残留的五氯苯酚含量,对整个测量过程的不确定度来源进行了分析,并对不确定度各个分量进行了评定与合成。当五氯苯酚测定结果为0.570mg/kg时,扩展不确定度为0.054mg/kg,并给出了检测结果不确定度表达式。     

电感耦合等离子体发射光谱法测定锂离子电池石墨负极材料中铁不确定度评定

采用电感耦合等离子体发射光谱法测定锂离子电池石墨类负极材料中铁含量,对测定结果的不确定度进行评定。根据JJF 1059.1—2012《测量不确定度评定与表示》和测定过程中的风险因素,建立数学模型和因果图,分析不确定度来源,计算合成标准不确定度和扩展不确定度。结果表明,测量重复性、标准曲线拟合、提取回收率对测定结果影响较大。当样品中铁含量为495.00 mg/kg时,其扩展不确定度为U=29.89 mg/kg,k=2。     

石墨炉原子吸收光谱法测定大米中镉含量的不确定度评定

依据GB 5009.15–2003用石墨炉原子吸收光谱法测定大米中的镉含量,分析测定结果的影响因素,归纳出测量不确定度的主要来源:标准工作曲线及方法回收率等,形成不确定度评定程序和方法,经量化和合成得到相对标准不确定度,从而求得扩展不确定度。当镉含量为0.098 mg/kg时,相对标准不确定度为0.0417,扩展不确定度为0.008 2 mg/kg(k=2)。     

气质联用法测定电器塑料产品中多环芳烃含量的不确定度

采用气质联用法对电器塑料产品中的多环芳烃进行了分析,通过建立数学模型,分析了测量不确定度的主要来源有样品质量、样品萃取液体积、样品萃取液测定浓度、试剂空白液测定浓度以及平均回收率。对各不确定度分量进行了评定,当多环芳烃含量为239.03mg/kg时,合成不确定为7.41mg/kg,扩展不确定度为14.82mg/kg。     

电感耦合等离子体原子发射光谱法测定塑胶中镉、铅、汞、铬含量的不确定度

对电感耦合等离子体发射光谱法测定塑胶中镉、铅、汞、铬含量的不确定度进行了评定.分析了测定过程中不确定度的主要来源,对各不确定度分量进行了量化.镉、铅、汞、铬的合成标准不确定度分别为0.146、2.27、1.71、1.06 mg/kg.     

高效液相色谱法测定婴幼儿用奶瓶中己内酰胺迁移量的不确定度评定

采用高效液相色谱法测定婴幼儿用奶瓶中己内酰胺迁移量,并对其测定的结果进行不确定度的评估。参照JJF 1059.1—2012 《测量不确定度评定与表示》和CNAS—GL 006：2019 《化学分析中不确定度的评估指南》中的规定与要求,分析己内酰胺在测定过程中的各种不确定度来源。水基食品模拟物处理的样品中己内酰胺的迁移量测定结果为12.213 mg/L,其扩展不确定度为1.29 mg/L,结果表示为(12.21±1.29) mg/L,k=2;酸性食品模拟物处理的样品中己内酰胺的迁移量测定结果为15.608 mg/L,扩展不确定度为1.48 mg/L,结果表示为(15.61±1.48) mg/L,k=2;酒精类食品模拟物处理样品中己内酰胺所产生的迁移量测定结果为18.299 mg/L,扩展不确定度为1.84 mg/L,结果表示为(18.30±1.84) mg/L,k=2;油基食品模拟物处理样品中,己内酰胺的迁移量测定结果为10.232 mg/kg,扩展不确定度为0.99 mg/kg,结果表示为(10.23±0.99) mg/kg,k=2。通过评估发现,不确定度主要的影响因素是标准溶液的配制...     

蛋卷中三聚氰胺HPLC定量分析结果不确定度的评定

建立了HPLC法测定蛋卷中三聚氰胺含量的不确定度模型,通过对测试方法流程进行分析,确定不确定度来源,对各不确定度分量进行了评定和量化。求得当蛋卷中三聚氰胺含量为8.49 mg/kg时,扩展不确定度为0.32 mg/kg。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。