p450酶活性中心催化12二溴3氯丙烷的机理及动力学同位素效应

发展有毒物质被细胞色素P450酶催化转化途径和机理的计算毒理预测方法,对于污染物的风险评价具有重要意义.本研究通过密度泛函理论计算,揭示了细胞色素P450酶活性中心（CpdI）催化氧化1,2-二溴-3-氯丙烷（DBCP）的反应机理,并考察了动力学同位素效应的影响.结果显示,DBCP羟基化反应与烷烃羟基化反应机理存在明显差异.不同于一般的双态反应,DBCP羟基化反应是自旋选择性反应.此外,DBCP羟基化第二步反弹过程中的能垒明显的高于烷烃羟基化过程.自旋密度分析表明,DBCP羟基化反应的氢提取步骤是一个氢原子转移过程.DBCP羟基化反应具有明显的动力学同位素效应（KIE）,且温度和隧道效应对KIE值具有明显的影响.本研究可为卤代烷烃类化合物的生物转化预测提供理论依据

介绍张冲关于加快开发我国水电的设想

我国水能资源丰富,其特点是80%的水能蕴藏在深山峡谷的江河之中,水量充沛,落差集中,这是优点;但另一方面,深谷江河上谷窄山高,水深流急,交通不便,给用常规方法筑坝带来难以克服的困难。能否找到适合深

TECTONIC EVOLUTION AND SEQUENCE STRATIGRAPHY of PASSIVE CONTINENTAL MARGIN DEEP-WATER BASIN(NORTH BONAPARTE BASIN)

北波拿巴盆地油气资源十分丰富,是具有重要价值的战略远景区,其构造演化模式和层序地层学发育样式具有一定的特殊性。通过对北波拿巴盆地的地震资料、钻、测井资料和岩心资料的综合研究,分析北波拿巴盆地的构造演化模式和层序地层学发育样式,提出了陆裾转换不整合和俯冲碰撞不整合的划分依据和识别标志。North Bonaparte basin is rich in oil and gas resources,and also is an important area of strategy,and its tectonic evolution pattern and stratigraphy sequences are unique.Through the integrated researches of seismic data,core and log data,the tectonic evolution pattern and stratigraphy sequences have been analyzed,and identification characters of the continental rise transform unconformity and subduction and collision unconformity have been pointed out.国家重点基础研究发展规划项目(2009CB219407);澳大利亚西北陆棚北波拿巴盆地NT/P76区块层序、沉积相研究项

老人椅辅助站立机构参数优化设计

简述了老人椅辅助站立机构的工作原理,并对辅助站立机构进行传力特性分析,得到机构传动角运动规律。针对传统辅助站立机构传力特性和机构效率较差的问题,利用多体动力学仿真软件ADAMS对该机构进行了运动仿真及参数化建模,然后以辅助站立四杆机构传动角取得最大值为目标进行优化分析,最终确定了影响传动角主要设计变量的参数。研究结果表明,通过优化后,辅助站立机构的传动角得到明显增加,提高了机构传力特性和机械效率,同时也增大了机构的前倾程度,有助于老人站立

The Adsorption and Decomposition of CH_3OH,CO,CO_2 on Clean and Preoxidised Pd(111)SurFaces

用uPS和XPS等表面分析方法，研究了CH＿3OH、CO和CO＿2等小分子在Pd（1111）单晶及其预氧化表面的吸附性质。室温下，CH＿3OH在清洁的Pd（111）表面以CH＿3O￣-的形态被吸附，部分分解为CH＿2；CO在Pd（111）表面首先以分子形式被吸附，尔后部分解离成C￣（8-）；CO＿2在Pd（111）表面分解C￣（8-）.CO＿（2b）和C-O键的活化与Pd表面的电子密度有关，氧化使Pd表面断裂C-O键的活性降低，而断裂O-H和C-H键的活性仍然存在。The interactions of CH_3OH,CO,CO_2 on clean and preoxidised Pd(111)sur-Faces were studied by both UPS and XPS,At room-temperature,CH_3 OH adsorption on clean Pd(111) surFace was Found to methoxy,CH_3O(ad)species,subsequently, C-O bond was activated toform adsorbed methyl, CH_x.Only C(ad)and CO(ad)species were observed when CO adsorbed on theclean Pd(111) surFace, but C(ad),CO(ad) and speciesl were observed when CO_2 adsorbed onthe clean Pd(111) surFace.On preoxidised Pd(111)surFace, methanol adsorbed as CH_3O(ad) andCHx (ad ),CO adsorbed only as CO(ad ).There were not any activation that CO_2 on preoxidised Pd(111)surFace.It were Found that the activation of C-H and C-O bonds depended on surFace electronintensity.On preoxidised surFaces the activation of C-O bonds decreased , but the activation of O-Hand C-H bonds still existed