土壤电化学性能对铀、锶、铯分配系数的影响及机理探讨

通过静态吸附实验研究了土壤pH值、正电荷AEC值、永久负电荷CECp值等电化学性能对核素铀、锶、铯分配系数的影响,进一步结合XRD物相分析结果,对土壤滞留核素的机理进行了探讨.研究结果表明:所研究的两种土质类型中,铀的分配系数(U-Kd值)均随溶液初始pH值的减小、AEC值的增大而增大;铯、锶的分配系数与土壤的CECp值、蒙脱石和伊利石总含量呈正相关关系;Cs 、Sr2 离子势及其相应水合离子半径的差异造成土壤中铯的分配系数显著大于锶的分配系数.     

反应堆一回路不锈钢管道沉积物制备及去污的模拟研究

反应堆一回路管道通常以不锈钢为基材,长期运行中面临沉积物的产生及大量积累的问题.本文通过溶液反应模拟沉积物的产生,采用的水溶液中含有Ca2+、Mg2+,以及裂片核素137 Cs和活化核素60 Co的稳定同位素阳离子133 Cs+和59 Co2+,CO32-、SO42-等阴离子,以及基材氧化物Fe2 O3等;开展了沉积物...     

极低放射性废物填埋场土壤理化指标的测定

如何安全、经济、妥善地处理和处置核废物,成为核工业可持续发展所面临的重要问题之一[1~4]。目前,退役过程中产生的极低放废物的常用处置方法是就近选址进行填埋处置。那么填埋场场址地段的地球化学特征直接决定填埋场的安全性、可靠性[5]。以铀为例,在酸性条件下以UO22 形式存在,而pH值大于7时,会形成U2O52 ,UO2(OH)2,UO2(OH) 等水解聚合产物,使得铀既有吸附和交换作用,又有沉淀作用,会加速U的吸附[6,7]。同样,核素的化学形态同样也会受到氧化还原反应的影响。因此,查明极低放废物填埋场场址地段土壤理化性质,可为了解核素在土壤介…     

双系统离子色谱法同时检测蓝藻培养液中阴、阳离子

采用双系统离子色谱仪,应用电导检测器,建立了蓝藻培养液中7种阴离子(F-、Cl-、Br-、PO43–、NO2-、NO3-、SO42-)和6种阳离子(Li+、Na+、K+、Ca2+、Mg2+、NH4+)的同时定量检测方法.7种阴离子和6种阳离子在优化的分析条件下均能完全分离,标准曲线相关系数均大于0.999,加标回收率为...     

土壤颗粒表面电场作用下固-液界面Mg2+-K+与Ca2+-K+交换动力学的比较研究

通过恒流法研究了不同表面电场作用下Mg2+、Ca2+吸附动力学. 结果发现: (1)实验初期阶段是强静电力作用下的零级动力学过程和一定反应时间后的弱静电力作用下的一级动力学过程, 且零级速率过程和一级速率过程之间存在明显的转折点; (2)不同电解质构成中Ca2+的吸附速率明显快于Mg2+的, 平衡吸附量也大于Mg2+的, 且Ca2+在土壤颗粒表面的覆盖度比Mg2+在土壤颗粒表面的覆盖度高; (3)离子的相对有效电荷系数与土壤颗粒表面电场作用的不同是各体系中Ca2+、Mg2+吸附动力学有差别的根本原因; (4)根据离子吸附的理论模型可以分别计算出速率系数、平衡吸附量、离子在土壤颗粒表面的覆盖度以及固定液的体积, 这些参数可以定量评估土壤颗粒表面电场对离子吸附动力学的影响.     

土壤颗粒表面电场作用下固-液界面Mg~(2+)-K~+与Ca~(2+)-K~+交换动力学的比较研究

通过恒流法研究了不同表面电场作用下Mg2+、Ca2+吸附动力学.结果发现:(1)实验初期阶段是强静电力作用下的零级动力学过程和一定反应时间后的弱静电力作用下的一级动力学过程,且零级速率过程和一级速率过程之间存在明显的转折点;(2)不同电解质构成中Ca2+的吸附速率明显快于Mg2+的,平衡吸附量也大于Mg2+的,且Ca2+在土壤颗粒表面的覆盖度比Mg2+在土壤颗粒表面的覆盖度高;(3)离子的相对有效电荷系数与土壤颗粒表面电场作用的不同是各体系中Ca2+、Mg2+吸附动力学有差别的根本原因;(4)根据离子吸附的理论模型可以分别计算出速率系数、平衡吸附量、离子在土壤颗粒表面的覆盖度以及固定液的体积,这些参数可以定量评估土壤颗粒表面电场对离子吸附动力学的影响.     

无机离子对Ag_3PO_4可见光降解亚甲基蓝的影响

以亚甲基蓝(MB)为模拟废水污染物,Ag3PO4为光催化剂,固定污染物初始浓度、催化剂用量、光照强度和照射时间等,探讨不同浓度的无机阴、阳离子(NO-3、Cl-、SO2-4、Na+、Ca2+、Mg2+、Al 3+)对Ag3PO4光催化降解偶氮染料MB的影响.结果表明,Na+和NO-3对Ag3PO4光催化降解MB没有明显的影响;Cl-在一定程度上对MB的降解具有促进作用;SO2-4、Ca2+、Mg2+、Al3+在不同程度上抑制了该光催化反应的进行,且抑制顺序为SO2-4Ca2+Mg2+Al 3+.     

HCO_3~-浓度对油气田中CO_2腐蚀的影响

应用动电位扫描和失重法研究HCO3-对油气田CO2腐蚀的影响.实验表明,当HCO3-浓度低于0.042 mol/L时,随着HCO3-浓度的增加,溶液pH升高,H+的还原速率(阴极电流密度)下降;HCO3-浓度增至0.126 mol/L时,溶液中的H2CO3、HCO3-的直接还原占主导地位,故阴极过程随HCO3-浓度的上升而加速,对阳极过程,在HCO3-浓度低于0.042 mol/L下,主要为活化过程,而且其阳极溶解电流(密度)随HCO3-浓度的增加而下降;HCO3-浓度增至0.126 mol/L时,阳极过程出现明显的活化-钝化行为.高温高压腐蚀试验显示,材料的腐蚀速率随介质HCO3-浓度的增加而下降.SEM、EDS、XRD分析表明,在较低的HCO3-浓度下,腐蚀产物膜的主要成分为FeCO3晶体,HCO3-浓度较高时,则腐蚀产物主要为Ca、Mg的化合物,并形成Ca(Fe,Mg)(CO3)2复盐.在高pH值下,Ca2+、Mg2+比Fe2+更容易沉积.     

化妆品中阴阳离子的快速测定及其用于化妆品鉴别的研究

用离子色谱电导检测器对黑泥类化妆品中的阴、阳离子(Na+,NH+4,K+,Mg 2+ ,Ca 2+ ,Cl-,Br-,NO-2,NO-3和SO 2- 4)进行了测定。阳离子分离条件: 阳离子交换柱ICS C25,均苯四甲酸淋洗液浓度2.0 mmol/L ,流速0.6 mL/min ;阴离子分离条件: 阴离子交换柱Shim pack IC A1,淋洗液为2.5 mmol/L 邻苯二甲酸和2.4 mmol/L 三羟基氨基甲烷,流速1.0 mL/min 。结果表明,上述10种离子在较宽浓度范围内有良好     

工程水质分析结果的审查

工程水质分析数据中阴、阳离子含量之间,矿化度与阴、阳离子含量之间,pH值与CO32–,HCO3–,游离CO2含量之间,游离CO2与侵蚀性CO2含量之间,以及Ca2+,Mg2+与阴离子含量之间均存在内在关系,总结其一般性规律并据此对工程水质分析结果进行审查,可以判断分析数据是否合理、可靠。     

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。     

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.     

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.     

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。