Japanese试剂的环化反应

利用Japanese试剂与含活泼氢的双官能团化合物的环化反应,合成了含N-P-N,N-P-O的五元磷杂环化合物,并用IR,NMR和MS对新化合物进行了表征。     

西松烷型二萜内酯的全合成进展

按照内酯环的大小综述了西松烷二萜的合成方法。     

Stereoselective allyl amine synthesis through enantioselective addition of diethylzinc and [1,3]-chirality transfer: synthesis of lentiginosine and polyoxamic acid derivative

A new synthetic method for the preparation of allyl amines has been developed. The key steps of this method are enantioselective addition of diethylzinc and [1,3]-chirality transfer through the [3.3] sigmatropic rearrangement of allyl cyanates. Stereocontrolled syntheses of lentiginosine (1) and polyoxamic acid derivative 2 from a common intermediate 7 derived from D-tartaric acid (8), have been accomplished.     

用于紫外光谱水质分析的Boosting-偏最小二乘法

为提高水质参数总有机碳(TOC)的紫外吸收光谱分析的预测精度,提出一种基于Boosting理论的迭代式回归建模算法,并根据统计学习理论提出一种新的迭代停止判据,可有效防止过拟合,显著提高模型预测精度。为评估所提算法的性能,分别采用本算法和3种常用的光谱分析方法,即偏最小二乘、主成分回归和人工神经网络,对自行研制的紫外光谱水质分析仪实测的一组数据进行了建模和预测。计算结果表明:相对于其他3种方法,本算法具有生成的模型预测精度高的显著优势。     

优化沉积参数对微晶硅薄膜太阳电池性能的影响

本文主要采用甚高频等离子体增强化学气相沉积技术制备了不同硅烷浓度、辉光功率和反应气体流量的单结微晶硅薄膜太阳电池。电池的I-V测试结果表明:电池的开路电压随功率的降低、硅烷浓度和气体流量的增加而增加,而对应的短路电流密度在一定的硅烷浓度条件下达到最大,填充因子也在逐渐的增加。文中对具体内容进行了详细的分析。     

Structure of (meso-5,10,15,20-tetraphenylporphyrinato) dichlorophosphorus(V) chloride, [P(tpp)Cl2]+Cl−

The title compound [P(tpp)Cl₂]⁺Cl^– crystallizes in the space group P2₁/n witha=10.701(2),b=24.860(2),c=14.799(2), =94.24(2)°,Z=4. The phosphorus atom has an octahedral coordination geometry formed by the four nitrogen atoms (Np) of the porphyrinato group and the two chloride ions. The average phosphorus-chloride distance is 2.150(1) Å, with phosphorus situated 0.006 Å below the porphyrin ring.     

Icosahedral symmetry in clusters

First principles calculations and simulations based on interatomic potentials together with experimental studies of abundance spectrum suggest icosahedral structures to be common for some magic clusters of diverse systems such as rare gases, metals, covalently bonded systems and water. Close packing models obtained from pair potentials are shown to be good representations of the structure of rare gas clusters. However, the electronic structure is found to play the important role in the atomic structure and related properties of other clusters. Results of recent studies of fullerenes, their derivatives as well as some large icosahedral metal clusters containing several thousand atoms are also presented. Further results on doped icosahedral clusters are discussed which hold promise for the development of new materials and for understanding the occurrence of icosahedral order in several aluminum alloys.     

高温氧化-化学发光检测法测定水中总氮

采用高温氧化-化学发光检测法（high temperature oxidation ＆ chemiluminescence, HTO-CL）进行水质总氮（TN）的在线测定。总氮浓度（CN）与化学发光的强度（IN）呈良好的线性关系，线性区间为0．05～100mg／L。对真实水样采用本方法进行测定，其结果与国标方法相符，回收率在90％～110％之间。以本方法为工作原理的TN-2000型总氮测定仪可用于地表水质及污水的在线监测。     

反式氢化茚酮的合成在全合成甾体上的应用

反式氢化茚酮是全合成甾体的合成子。本文综述了五种合成方法:即分子内 Diels-Alder 反应,分子内 Michael 反应;联合 Cope-Claisen 重排;Lewis 酸催化环合γ,δ-不饱和羰基化合物以及二环庚烷的裂解。