化学溶解和电感耦合等离子体质谱法研究地质样品中铂族元素的物相分布

建立了基于化学逐级溶解、火试金预浓集和电感耦合等离子体质谱分析的地质样品中铂族元素的物相分析新流程。应用逐级溶解，地质样品可被分成即水溶相、可交换相、碳酸盐相、Ｆｅ／Ｎｉ金属相、硫化物相、氧化物相、硅酸盐相和残渣相８个组分。详细研究了溶解实验中试剂、温度、酸度和时间等实验参数。作为应用的实例，研究了丹麦Ｓｔｅｖｎｓ Ｋｌｉｎｔ Ｋ／Ｔ界线样品中５个铂族元素的物相分布。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定金属铬中的钒

采用15mL盐酸和5mL硝酸混合酸溶解样品,选择V 292.464nm谱线做光谱干扰实验,发现Cr对此谱线无光谱干扰,由于样品中含大量Cr离子,故采用标准曲线基体匹配进行测试,以消除Cr基体带来的基体干扰,建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定金属铬中钒含量的分析方法。结果表明:基体效应对钒的标准曲线线性并无影响,钒的质量浓度在0.1~20μg/mL,其线性相关系数均不小于0.999 8,方法中钒的检出限为0.001 5μg/mL。按照实验方法测定金属铬中钒,结果的相对标准偏差(RSD,n=10)为0.89%。方法适用,结果令人满意。     

固相Ni在含Fe液相Zn中的溶解行为

利用金相显微镜、扫描电镜及能谱分析研究了固相Ni在450℃静止的含Fe液相Zn中的溶解行为,并利用自然对流下的质量传输准数方程和考虑金属间化合物层形成的溶解速率模型,分析了固相Ni在含Fe液相Zn中的溶解速率控制机制.结果表明:固相Ni浸入含Fe液相Zn中会形成与纯液相Zn中相似的γ-Ni2Zn5和δ-NiZn8相层;但由于液相中含Fe,合金层外一定区域内有Γ2-Fe5Zn6Ni89粒子生成;Ni在不饱和Fe液相Zn中的溶解速率控制步骤与在纯液相Zn中相同,为界面反应和合金相层中的扩散速率所控制,而Ni在过饱和Fe液相Zn中溶解的主要控制机制是溶质Ni原子通过液相Zn中浓度边界层的扩散.说明液相Zn中所含的Fe加速了Ni的溶解.     

ICP-MS的KED模式测定磷酸加王水复溶土壤样品中的二十种金属元素

在研究锗测定时,磷酸先溶解样品,后加入王水复溶,可同时测定锂、铍、钪、钒、铬、钴、镍、铜、锌、锗、钼、镉、钡、镧、铈、钨、铊、铅、钍和铀元素。研究ICP-MS的最佳测量模式、最佳工作状态,以铑为内标校正仪器的漂移。通过选择高、中、低几个国家一级水系沉积物和土壤标准物质随同样品一起实验溶解建立标准曲线,消除消解、分取、定容中带来的不确定误差和基体干扰,选择8个土壤标准物质为实验样本。最终结果表明,该实验方法准确度(ΔlgC)小于0.1,精密度(RSD)小于8%,该方法满足测定要求,适用于地质普通样品的多金属检测。#$NL     

铜氨络离子的形成和空间构型的探究

基于化学平衡的原理,通过简单的计算解释了氢氧化铜溶于氨水的反应机理,同时基于价键理论和Jahn-Teller效应来阐述铜氨络离子以及其他铜离子配合物的形成过程。     

Molecular model of phenolic polymer dissolution in photolithography

The resolution of photolithographic processes has advanced to the point that difficulties, such as line‐edge roughness, associated with phenomena occurring at molecular length scales are becoming important. In order to control these phenomena, it is necessary to understand them. To that end, a numerical model has been used to simulate the dissolution of phenolic polymers in aqueous base. The simulation applies the Critical Ionization Model to a rectangular‐lattice representation of the polymer matrix. The model has been adapted to describe the dissolution process that is responsible for photoresist function. Both continuum and molecular versions of the model are presented. The Continuum Model yields dissolution profiles that approximate the contours of the calculated spatial variations in chemical blocking (blocking profile). An algorithm has been developed to connect individual cells to form polymer chains, and to fill the lattice in a way that produces a Gaussian chain length distribution. The model employs only a single adjustable parameter, the time‐step correction factor (assuming one can measure the probability of ionization once a site encounters the developer). The Molecular Model predicts a dissolution rate that decreases non‐linearly with respect to degree of chemical blocking, as is observed experimentally. Dissolution profiles can be generated with the Molecular Model based either on this calculated dependence of the dissolution rate on blocking fraction or from direct application of the model to a blocking profile. The probabilistic nature of the model introduces edge roughness of the same degree as that observed experimentally. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2103–2113, 1999     

316L不锈钢应力腐蚀研究进展

316L不锈钢具备良好的力学性能、焊接性能、耐蚀性能,被广泛应用于化工管道、船舶及核电等领域。因其应用环境复杂,316L不锈钢在特定介质环境和拉应力的协同作用下,易发生应力腐蚀开裂,导致严重事故。概述了316L不锈钢应力腐蚀裂纹萌生及扩展的规律,总结了其应力腐蚀的阳极溶解和氢致开裂两种微观主导机制的特点。在此基础上,针对介质环境、材料、表面应力状态3个影响因素,综述了近年来通过调节介质环境的pH、溶液浓度、引入压应力、优化微观结构及涂层工艺等方面,改善316L不锈钢应力腐蚀性能的研究进展。最后,基于316L不锈钢面临的应力腐蚀问题,从应力腐蚀机制和防护措施两方面展望了316L不锈钢应力腐蚀的研究热点和方向。     

Disentanglement and reptation during dissolution of rubbery polymers

The dissolution mechanism of rubbery polymers was analyzed by dividing the penetrant concentration field into three regimes that delineate three distinctly different transport processes. The solvent penetration into the rubbery polymer was assumed to be Fickian. The mode of mobility of the polymer chains was shown to undergo a change at a critical penetrant concentration expressed as a change in the diffusion coefficient of the polymer. It was assumed that beyond the critical penetrant concentration, reptation was the dominant mode of diffusion. Molecular arguments were invoked to derive expressions for the radius of gyration, the plateau modulus, and the reptation time, thus leading to an expression for the reptation diffusivity. The disentanglement rate was defined as the ratio between the radius of gyration of the polymer and the reptation time. Transport in the second penetrant concentration regime was modeled to occur in a diffusion boundary layer adjacent to the polymer-solvent interface, where a Smoluchowski type diffusion equation was obtained. The model equations were numerically solved using a fully implicit finite difference technique. The results of the simulation were analyzed to ascertain the effect of the polymer molecular weight and its diffusivity on the dissolution process. The results show that the dissolution can be either disentanglement or diffusion controlled depending on the polymer molecular weight and the thickness of the diffusion boundary layer. © 1996 John Wiley & Sons, Inc.     

CO2和O2共注入下方解石溶解对黄铁矿氧化固铀的影响

我国大型可地浸砂岩型铀矿床普遍存在黄铁矿和方解石与铀矿物密切共生现象。中性地浸采铀过程中O₂和CO₂的共注入会诱导黄铁矿氧化和方解石溶解,目前针对二者共存体系中方解石溶解对黄铁矿氧化固铀的影响尚不明确。本文通过静态批实验和数值模拟的方法对比研究了CO₂和O₂条件下方解石溶解对黄铁矿氧化固铀的影响。结果表明：无CO₂分压下中性Tris缓冲体系中黄铁矿氧化对U(VI)的吸附率高达90%,有CO₂分压下碳酸铀酰体系中铀的固定率明显降低,约有32%的铀被吸附。在方解石和黄铁矿共存体系中,单独通O₂条件下铀的吸附率为27%,CO₂和O₂共通时黄铁矿氧化对铀的吸附率仅为2%,结合数值模拟结果表明O₂+黄铁矿+方解石体系和CO₂+O₂+黄铁矿+方解石体系中Ca₂(UO₂)(CO₃     

混合酸溶-电感耦合等离子体发射光谱(ICP-OES)法同时测定多金属矿石中铜铅锌钼

为解决多金属矿石的传统分析方法中样品前处理冗长复杂、Mo的线性范围窄、不能与Cu、Pb、Zn同时测定的缺点,通过考察溶样体系、仪器工作条件、干扰及消除,建立了电感耦合等离子体发射光谱(ICP-OES)同时测定Cu、Pb、Zn、Mo四种元素的方法。结果表明,方法测定范围较宽(0.001%～20.0%),各元素校准曲线线性相关系数均在0.999 5以上,检出限为5～9μg/g。用国家标准物质进行验证,方法精密度(RSD,n=12)为0.020%～5.0%,相对误差为-4.61%～4.17%,加标回收率为88.0%～108%。实际样品的测定结果与传统方法一致,方法适合大批量、多成分分析。