过渡金属催化下的烯烃硼氢化反应

本文综述了在过渡金属尤其是铑络合物催化下烯烃与CB的硼氢化反应在化学、位置和立体选择性的进展,对它们的机理也进行了讨论。     

SrTiO_3表面O_2,H_2_O吸附的UPS,XPS研究

观察到还原SrTiO_3_, 表面三价Ti 离子引起的表面态的存在.分析了它在太阳光分解水中所起作用, 以及光照在恢复活性中的作用. 关键词：     

Justification of a Monte Carlo Algorithm for the Diffusion-Growth Simulation of Helium Clusters in Materials

A theoretical analysis of a Monte Carlo （MC） method for the simulation of the diffusion-growth of helium clusters in materials is presented. This analysis is based on an assumption that the diffusion-growth process consists of first stage, during which the clusters diffuse freely, and second stage in which the coalescence occurs with certain probability. Since the accuracy of MC simulation results is sensitive to the coalescence probability, the MC calculations in the second stage is studied in detail. Firstly, the coalescence probability is analytically formulated for the one-dimensional diffusion-growth ease. Thereafter, the one-dimensional results are employed to justify the MC simulation. The choice of time step and the random number generator used in the MC simulation are discussed.     

催化KBH4 还原红霉素6,9-亚胺醚的研究

在催化剂作用下,红霉素6,9-亚胺醚经KBH4还原制备阿奇霉素前体--氮红霉素.考察了催化剂的活性组分、载体及其制备条件对催化性能的影响.最佳催化剂为:以Pt为活性组分[w(Pt)=1%],未经处理的活性炭(C)为载体,Pt/C用水合肼还原.以1%Pt/C催化还原反应,转化率93%,收率70%.     

电化学沉积金纳米线结构及其电学特性

用电化学沉积方法，在有机介孔模板上制备出直径为90 nm的金纳米线.透射电子显微镜（TEM）分析结果表明，纳米线表面光滑并呈单晶结构.去除有机模板的金纳米线阵列用扫描电子显微镜（SEM）测试，纳米线顶端呈平台状，直径分布均一.我们利用原子力显微镜（AFM）测量了金纳米线阵列的微观结构，得到与SEM相一致的结果.在大气和室温条件下，用导电AFM针尖在接触模式下测量了单根纳米线的轴向I－V特性曲线，其结果为金属性.     

弧形调强放射治疗对剂量计算方法的要求

在弧形调强放射治疗的治疗计划设计中, 由于包含有很多照射方向, 调强最优化的射束元矩阵计算需要很大的计算量和存储量, 为提高计算效率常使用简化剂量计算模型计算射束元矩阵, 因此有必要研究简化模型对治疗计划质量产生影响。 对一个模拟例子和一个临床实例, 使用没考虑散射效应的原射线剂量计算模型计算射束元矩阵, 由此进行最优化计算。 在得到最优化强度分布后, 通过比较原射线剂量计算模型和微分卷积剂量计算模型得到的剂量分布, 研究了不同射束数目条件下, 使用简化剂量计算模型计算射束元剂量矩阵对最终的剂量分布质量的影响。 结果表明, 在射线束很多的情况下(对应弧形调强照射）, 用简化的剂量计算模型, 即不考虑散射来计算射束元剂量矩阵, 会导致靶区剂量分布的质量大大低于预期的剂量分布质量, 因此, 弧形调强放射治疗的最优化计算中, 有效考虑散射的影响是必要的。 In the treatment planning for arc intensity modulated radiation therapy, because many irradiation directions are involved, the computing time and storage space needed for calculating beamlet dose matrices in optimization is quite heavy. In order to improve the computation efficiency, the simplified dose calculation is often used for the calculation of the dose matrices. Thus, it is deserved to study how this simplification could influence the quality of the treatment plan. In this paper, a simulation and a clinical case are adopted. Using the primary dose calculation model without taking into account the scattering effect to generate the dose matrices of beamlets, the optimization for beam intensity profile are firstly carried out. Then, based on the obtained intensity profile, the dose distributions are recalculated by using the primary dose calculation model and the differential convolution superposition dose calculation model which is more accurate but more time consuming. By comparing dose distributions obtained by this two models, the influence of using simplified model for dose matrix calculation on beam profile optimization is studied. The results demonstrate that when the beam number is large(corresponding to the arc modulated radiation), using the simplified model for the calculation of dose matrix of beamlets will reduce the quality of dose distribution greatly comparing with the expected dose distribution quality. Thus it is very necessary to correctly take into account the scattering effect in beam profile optimization for the arc intensity modulated radiation therapy.     

EMP Formation in the Co(Ⅱ) Doped ZnTe Nanowires

Co(Ⅱ) doped Zn Te nanowires are prepared by a thermal evaporation method. The power and temperature dependent micro-photoluminescence spectra of single nanowire demonstrate the double bands near its band edge,and the ferromagnetism behavior for these nanowires is identified. The occurrence of excitonic magnetic polaron(EMP) can account for the second emission band for its higher binding energy and ferromagnetic coupling. This EMP formation in a nanostructure will facilitate to realize magnetic modulation on confined excitons and will find new applications for spinpolarized nanophotonic devices.     

New Chiral N,S-Ligands with Thiophenyl at Benzylic Position. Palladium(II)-catalyzed Enantioselective Allylic Alkylation

Ｃｈｉｒａｌｌｉｇａｎｄｓｐｌａｙａｃｒｕｃｉａｌｒｏｌｅｉｎａｓｙｍｍｅｔｒｉｃｃａｔａｌｙｓｉｓ .Ｔｏｄａｔｅａｖａｒｉｅｔｙｏｆｌｉｇａｎｄｓｈａｖｅｂｅｅｎｓｙｎｔｈｅ ｓｉｚｅｄａｎｄｐｒｏｖｅｄｔｏｂｅｅｆｆｅｃｔｉｖｅ .Ａｍｏｎｇｔｈｅｍｔｈｅｌｉｇａｎｄｓ1ｗｉｔｈｂｏｔｈｃｏｏｒｄｉｎａｔｅａｔｏｍｓａｔｂｅｎｚｅｎｅｒｉｎｇ ｐｏｓｉｔｉｏｎｓｓｈｏｗｇｏｏｄｔｏｅｘｃｅｌｌｅｎｔａｓｙｍｍｅｔｒｉｃｉｎｄｕｃｔｉｏｎｉｎｃａｔａｌｙｔｉｃａｓｙｍｍｅｔｒｉｃｒｅａｃｔｉｏｎｓ …     

Numerical study of shock diffraction in dusty gases

ＮＵＭＥＲＩＣＡＬＳＴＵＤＹＯＦＳＨＯＣＫＤＩＦＦＲＡＣＴＩＯＮＩＮＤＵＳＴＹＧＡＳＥＳＷｕＱｉｎｇ－ｓｏｎ（吴清松）ＺｈｕＨｏｎｇ（朱红）ＸｕＹａｎ－ｈｏｕ（徐燕侯）（ＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙｏｆＣｈｉｎａ,...