熔盐电解合成希土六硼化物的研究——REBO3、LiBO2和LiF体系熔盐电解合成RER6

本文在800℃和空气中电解REBO₃-LiBO₂-LiF熔盐体系合成了单相的REB₆.石墨川埚兼作容器和阳极.耐火金属棒如Cu和Mo等被悬吊在电解质中作为阴极.根据似二元体系LiBO₂-LiF和LiBO₂-LaBO₃的低熔点组成以La₂O₃、B₂O₃、Li₂CO₃和LiF为原料找到了具有较低熔点的熔盐体系.根据X射线粉末衍射,该熔体是由REBO₃、LiBO₂和LiF三个物相组成.     

铜离子交换改性的沸石催化剂上甲烷的非氧芳构化

已有研究表明，ＭｏＯ３／ＨＺＳＭ５是甲烷非氧芳构化的优良催化剂，在９７３Ｋ下甲烷转化率达６％～８％，苯选择性高于８０％，这为非氧气氛下甲烷的芳构化反应展示了非常诱人的前景［１～１２］．但是，该催化剂的活性和稳定性尚有待进一步提高，目前已有使用Ｐｔ，...     

铜（Ⅱ）－4－（吡啶－2′－甲基）－1，4，7，10－四氮杂环十三烷－11，13－二酮－α－氨基酸（5－取代邻菲罗啉）三元配合物的稳定性研究

用ｐＨ法在２５．０±０．１℃，Ｉ＝０．１ｍｏｌ·ｄｍ－３ＫＮＯ３条件下，测定铜（Ⅱ）－４－（吡啶－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮－α－氨基酸（５－取代邻菲罗啉）三元配合物的稳定常数；比较了带吡啶甲基二氧四胺大环配体和二氧四胺大环配体与Ｃｕ（Ⅱ）的配位能力、配位方式；研究了该三元体系配合物稳定性与配体α－氨基酸酸碱强度之间的直线自由能关系；探讨了Ｃｕ（Ⅱ）和５－取代邻菲罗啉之间的ｄ－ｐ反馈π键以及邻菲罗啉取代基Ｈａｍｍｅｔｔ诱导效应与该三元配合物稳定性之间的关系。讨论了４－（吡啶－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮和４－（喹啉－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮与Ｃｕｘｐｈｅｎ所形成配合物的不同空间结构及其对配合物稳定性产生的影响。     

有机金属络合物用于高分子富氧膜的研究进展

本文介绍了能够可逆吸附分子氧的有机金属络合物用于高分子富氧膜的研究进展，以及以双重吸附理论进行的膜的促进输送机理。     

液/液两相催化新进展--温控非水液/液两相催化

温控非水液/液两相催化,是指一类由两种或多种液态有机物组成的催化反应体系,其特点是体系的相态变化可通过温度来调控,即体系在高温时相互混溶呈均相,低温不溶分成两相,催化剂和产物分别处于两相,从而为解决均相催化剂分离难的问题开拓了一个新方向,是液/液两相催化研究领域最引人注目的进展之一.首次以"温控"为主线将氟两相催化作为温控液/液两相催化的一个特定类型纳入"温控非水液/液两相催化"范畴,并与其它通过温度来调控的有机液/液两相和作者提出的温控相分离催化串在一起作一较为详细的评述.     

C9‐Iridoids from Scrophularia buergeriana

Four new iridoids, buergerinins B–E ( 1 – 4 ), along with three known iridoids, were isolated from the roots of Scrophularia buergeriana. Their structures were identified on the basis of spectroscopic analysis.     

Optimization of a portable microanalytical system to reduce electrode fouling from proteins associated with biomonitoring of lead (Pb) in saliva

There is a need to develop reliable portable analytical systems for on-site and real-time biomonitoring of lead (Pb) from both occupational and environmental exposures. Saliva is an appealing matrix since it is easily obtainable, and therefore a potential substitute for blood due to existing reasonably good correlation between Pb levels in blood and saliva. The microanalytical system is based on flow-injection/stripping voltammetry with a wall-jet (flow-onto) microelectrochemical cell. Samples that contain as little as 1% saliva can cause electrode fouling, resulting in significantly reduced responsiveness and irreproducible quantitations. In addition, incomplete Pb release from salivary protein can also yield a lower Pb response than expected. This paper evaluates the extent of in vitro Pb-protein binding and the optimal pretreatment for releasing Pb from the saliva samples. Even in 50% by volume of rat saliva, the electrode fouling was not observed, due to the appropriate sample pretreatment and the constant flow of the sample and acidic carrier that prevented passivation by the protein. The system offered a linear response over a low Pb range of 1-10 ppb, low detection limit of 1 ppb, excellent reproducibility, and reliability. It also yielded the same Pb concentrations in unknown samples as did the ICP-MS. These encouraging results suggest that the microanalytical system represents an important analytical advancement for real-time non-invasive biomonitoring of Pb.     

微合金钢中稀土对沉淀相和性能的影响

在Nb(Ti,V）微合金钢中，主要沉淀相分别为Nb(C,N),(Nb,Ti)(C,N)和V（C，N）。稀土降低沉淀相完全溶解的温度，增大奥氏体中沉淀相析出的孕育期，降低析出速率，抑制奥氏体中沉淀相的析出，在铁素体相区，稀土提高沉淀相的析出速率和数量，促进沉淀相的析出，其中稀土对铌沉淀相析出的作用影响最强。锻态钢中，稀土有促进细化球化析出相的作用，随稀土含量增加，沉淀相析出数量增加，但过量稀土，促进作用又减弱，稀土在保持微合金钢强度的情况下，显著改善其冲击韧性，尤其是低温韧性，微合金钢中添加适量稀土可获得更佳的综合性能。