高纯硅溶胶成分标准物质稳定性研究

考察了高纯硅溶胶成分标准物质研制过程中影响稳定性的因素。根据高纯硅溶胶的物理化学性质,研究了影响高纯硅溶胶稳定的pH值、粒度分布、电解质等主要因素。提出了保持高纯硅溶胶稳定的措施,解决了高纯硅溶胶成分标准物质的稳定性问题,使标准物质稳定保存1年以上。     

基于激光三维扫描的gamma谱仪无源效率刻度方法的应用技术研究

对基于激光三维扫描的谱无源效率刻度方法在分析不同密度和形状样品的应用开展了研究。首先利用点源对高纯锗探测器进行表征，应用激光三维扫描仪对不同容器扫描建模，在无源效率刻度软件中调用相应的参数库和样品相应形状的三维模型，采用数值积分方法计算出不同能量下的探测效率。在几种不同形状的容器中装入已知放射性活度的样品，在被表征的高纯锗谱仪上进行测量，应用计算出的效率值分别处理分析得出样品中所含标准物质的活度值。结果表明在分析天然放射性核素时，测量值与标准物质证书给定值相对偏差不大于10%。因此，基于激光三维扫描的谱无源效率刻度方法，在可接受的测量不确定度下，现实工作中可用于不能被破坏、不规则样品的测量分析工作中。     

痕量分析中的浮选法

浮选法由于简便和可靠而广泛用于痕量分析,它主要用于预富集天然水和高纯金属中低ppm级或ppb级的痕量元素,但也可用于分离天然水和废水中的其它物质。目前,浮选法的应用可分为两类:沉淀浮选法和离子浮选法。本文讨论了痕量分析中浮选法的一般原理、技术和应用。     

氮中甲烷气体标准物质的研制

以甲烷纯度标准物质和高纯氮气为原料,采用称重法制备氮中甲烷气体标准物质。称量过程考虑了空气密度、天平线性系数、气瓶体积膨胀系数、转移和装卸过程产生的质量损失等因素。用气相色谱仪测定了高纯氮气中甲烷的含量,并对研制的标准物质进行了压力均匀性和时间稳定性检验。结果表明,研制的氮中甲烷气体标准物质标准值为10.0~1.00×10~3μmol/mol(U_(rel)=2%,k=2),该标准物质具备良好的均匀性和稳定性,可用于测量仪器的校准、测量过程的质量控制及分析方法的确认和评价。     

高纯氧化钇中痕量稀土杂质的柱分离富集和测定

对离子交换色层与电感耦合离子体原子发射光谱（ＩＣＰＡＥＳ）联用进行改进，用于高纯氧化钇中痕量稀土杂质的快速分离富集和测定。采用α羟基异丁酸（αＨＩＢＡ）作淋洗剂，对影响分离过程的主要因素（酸度、流速、试剂浓度等）、稀土杂质与试剂（αＨＩＢＡ）的再分离进行了研究。结果表明，分离可在８ｈ内完成，多数待测稀土元素的平均回收率为８０％～１０４％，可用于纯度为９９９９９％～９９９９９９％的高纯氧化钇分析。     

甲烷中微量噻吩气体标准物质研制

研制了甲烷中噻吩气体标准物质。以高纯噻吩、高纯甲烷为原材料，包装容器为4 L内壁经抛光处理的铝合金瓶，通过微量转移与常规相结合的方法完成了甲烷中微量噻吩气体标准物质制备。利用气相色谱法对标准物质进行了均匀性检验及稳定性考察。F检验和回归曲线法实验结果表明，该气体标准物质在压力为0.5～10 MPa范围内，均匀性良好，在常温条件下保存12个月稳定。采用称量法对该气体标准物质进行了定值，并对定值、均匀性和稳定性引入的不确定度进行了评定，该系列甲烷中微量噻吩气体标准物质标称摩尔分数为1.00～10.0μmol/mol，定值结果的相对扩展不确定度为2%(k=2)。     

气相色谱法制备高纯苯

研究了应用气相色谱法制备的高纯苯，并对其制备条件的选择及结果进行了讨论，结果表明：采用此法制备的苯其纯度为９９．９７％，而美国ＥＰＡ苯标准物质纯度为９９．７％《     

用高分辨率电感耦合等离子体-原子发射光谱仪测定高纯铬中的杂质元素

本文报道了高分辨率、高灵敏度的顺序扫描型电感耦合等离子体原子发射光谱仪(ICPS-8100)在高纯物质分析中的应用。对元素分析线进行优化选择;采用轴向观测方式,对高纯铬中μg/g级的杂质元素As、Sn、Sb、Pb进行直接同时测定,分析结果令人满意。     

ICP—MS测定高纯钪,钇,钬,铥和镥氧化物中痕量稀土杂质研究

研究了用电感合等离子体质谱测定高纯钪、钇、钬、铥和镥氧化物中痕量稀土杂质的方法，用内标法有效地校正了基体抑制效应，改善了精密度。与ＩＣＰ－ＡＥＳ分析相比，本法具有灵敏度高、流程简单快速、耗样少等特点，测定下限可降低１－２个数量组。方法可用于９９．９９９％的高纯稀土的分析。     

高纯稀土氧化物中微量稀土杂质光谱测定的研究——碳粉吸附负载固体粉末法

高纯稀土氧化物中微量稀土杂质光谱测定,国内外报导较少。本文对缓冲剂、基体等方面进行了初步探索,最后确定的方法可满足稀土杂质总量在0.00063％以上产品分析的要求。实验 (一)条件的选择 1.缓冲剂的选择:不同缓冲剂在稀土元素分析中的应用已有人进行过研究,值得注意的是氯化铯-碳粉已用于高纯氧化铕,氧化钇和氧化钕中微量稀土杂质的光谱测定。     

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.     

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。     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

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.

     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。