Total Synthesis of Tubulysin U and Its C‐4 Epimer

The Tup fragments of tubulysins were synthesized with a tandem reaction as the key step, and unexpected diastereoselectivity was observed in the first Grignard addition stage. The coupling of the enolate of a thiazolyl ketone with chiral sulfinimines furnished the backbone of the Tuv fragment with over 100:1 d.r. and high yield. Thus, tubulysin U and C‐4 epi‐tubulysin U were prepared in a highly selective and efficient manner. The results of the MTT assay furthermore indicated that C‐4 epi‐tubulysin U maintained significant growth inhibition activities against several cancer cell lines.     

Synthesis of dihydropyrazole‐bridged dinuclear ferrocenyl derivatives and their catalytic effect on thermal decomposition of ammonium perchlorate

Dihydropyrazole‐bridged dinuclear ferrocenyl derivatives (3a–3c) have been synthesized by the reaction of 1,3‐diferrocenyl‐2‐propen‐1‐on (1) with hydrazine, then acylation with acyl chloride directly. The structures were determined by mass spectrometry, IR and ¹H NMR spectroscopy. The compound 3c was characterized by single‐crystal X‐ray analyses. It was found that compounds 3a–3c have significant catalytic effect on the decomposition of ammonium perchlorate (AP). Compared with the thermal decomposition of pure AP, adding 3a, 3b and 3c in AP decreases its decomposition temperature by 78.8, 74.3 and 57.1 °C, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

基质中不同稀土离子晶场强度的比较分析

用计入电荷屏蔽作用后的晶场参数关系式, 比较分析了两种典型的激光材料激活离子Er3+和Nd3+在一系列晶体基质中的标量晶场强度. 理论上得到两者之间的比值为0.761, 从实验数据中得到的相应比值为0.731±0.017, 理论计算结果和经验关系式符合得相当好. 由此可以得到当不同稀土离子在同一种基质材料中占据相同的格位时, 其晶场强度的比值.     

变质CH13钢中Ce_2O_3异质核心作用的研究

采用变质处理大大减弱了CH13钢枝晶组织的元素偏析 ,使未变质CH13钢中的晶界碳化物得以消除 ,CH13钢的冲击韧性大大提高。通过热力学计算及二维点阵错配度计算 ,并采用电子探针定量分析等手段 ,证实Ce2 O3型稀土夹杂物可作为CH13钢中初生奥氏体的异质核心 ,细化枝晶组织 ,减弱合金元素偏析     

软件可靠性中NHPP模型趋势检验的U-图方法

对软件可靠性中一类重要的模型——非齐次泊松过程（ＮＨＰＰ）模型的趋势检验，构造了一列检验的统计量，独立同分布于均匀分布Ｕ（０，１）．并由柯尔莫哥洛夫检验判定所选择的可靠性增长趋势模型的合适性．本文方法可适用于完全数据和不完全数据．这里报告的方法，可以作为选择软件可靠性模型时的一种判断依据，以定量地评判选择的软件可靠性模型的优劣．     

激光诱导扩散区的温度监控

激光诱导扩散中的曝光区大小为１０μｍ量级，其温度分布的测量是较困难的。本文报道一我中极微小面积的不接触及控制。文中介绍测控原理、实验装置，给出测量结果。     

Computer simulations and analysis of structural and energetic features of crystalline cage energetic compound: 2, 4, 6, 8, 12‐pentanitro‐10‐(3, 5, 6‐trinitro (2‐pyridyl))‐2, 4, 6, 8, 12‐hexaazatetracyclo [5.5.0.03,11.05,9]dodecane

First principles molecular orbital and plane‐wave ab initio calculations have been used to investigate the structural and energetic properties of a new cage compound 2, 4, 6, 8, 12‐pentanitro‐10‐(3, 5, 6‐trinitro (2‐pyridyl))‐2, 4, 6, 8, 12‐hexaazatetracyclo [5.5.0.0^3,11.0^5,9]dodecane (PNTNPHATCD) in both the gas and solid phases. The molecular orbital calculations using the density functional theory methods at the B3LYP/6‐31G(d,p) level indicate that both the heat of formation and strain energy of PNTNPHATCD are larger than those of 2, 4, 6, 8, 10, 12‐hexanitro‐2, 4, 6, 8, 10, 12‐hexaazatetracyclo [5.5.0.0.0] dodecane (CL‐20). The infrared spectra and the thermodynamic property in gas phase were predicted and discussed. The calculated detonation characteristics of PNTNPHATCD estimated using the Kamlet–Jacobs equation equally matched with those of CL‐20. Bond‐breaking results on the basis of natural bond orbital analysis imply that C–C bond in cage skeleton, C–N bond in pyridine, and N–NO₂ bond in the side chain of cage may be the trigger bonds in the pyrolysis. The structural properties of PNTNPHATCD crystal have been studied by a plane‐wave density functional theory method in the framework of the generalized gradient approximation. The crystal packing predicted using the Condensed‐phase Optimized Molecular Potentials for Atomistic Simulation Studies (COMPASS) force fields belongs to the Pbca space group, with the lattice parameters a = 20.87 Å, b = 24.95 Å, c = 7.48 Å, and Z = 8, respectively. The results of the band gap and density of state suggest that the N–NO₂ bond in PNTNPHATCD may be the initial breaking bond in the pyrolysis step. As the temperature increases, the heat capacity, enthalpy, and entropy of PNTNPHATCD crystal all increase, whereas the free energy decreases. Considering that the cage compound has the better detonation performances and stability, it may be a superior high energy density compound. Copyright © 2015 John Wiley & Sons, Ltd.     

Catalytic performance of chitosan‐Schiff base supported Pd/Co bimetallic catalyst for acrylamide with phenyl halide

The chitosan‐Schiff base supported palladium and cobalt bimetallic complex was synthesized in a simple method and characterized by Fourier‐transform infrared spectroscopy (FT‐IR), powder X‐ray diffraction (XRD), and X‐ray photoelectron spectra (XPS). It was found that the catalyst has great activity and stability in the coupling of acrylamide (AA) with the phenyl halide. The influence of various bimetallic catalysts, the different molar ratio of Co/Pd, the bases, the amount of the catalyst and base, and the molar ratio of iodobenzene/AA on the reaction were investigated. The results showed that the catalytic activity of the molar ratio of Co/Pd (3/1) was the best when the iodobenzene was used as a substrate. The yield of the cinnamamide did not change significantly after ten runs. It has been revealed that the catalyst was efficient for the reaction. Copyright © 2009 John Wiley & Sons, Ltd.     

滑坡预报的几个基本问题

在滑坡预报研究中，必须首先解决与预报密切相关的一些基本问题。否则，往往导致预报误差很大或者预报失败。根据作者的初步探索，本文重点讨论了滑坡预报的分类及定义、预报参数及其监测点的选取、变形突变现象的分析与处理以及斜坡变形阶段的定量判断等基本问题。     

硝酸铈对钙调素及调节蛋白Ca~(2 )-ATP酶基因表达的影响

运用逆转录聚合酶链式反应研究了硝酸铈对大白鼠肝脏CaMⅠ ,PMCA1b基因表达的影响。腹腔注射高、低浓度硝酸铈均不会引起CaMⅠ ,PMCA1b基因表达的变化 ,提示硝酸铈对钙调素、Ca2 ATP酶的影响可能仅处于转录后水平。