非线性弹性及全量弹塑性有限元分析中的一致性切线模量

本文导出了非线性弹性及全量弹塑性有限元分析中的一致性切线模量,从而可以保持牛顿迭代法固有的平方收敛速度.指出了某些文献中关于切线模量的不正确表述,并以数值算例验证了本文方法的正确有效.     

Growth of oriented GaN nanowires by controlling nucleation conditions

GaN nanowires (NWs) were grown on GaN(0001) coated sapphire substrate with Ni/Au catalyst by using metalorganic chemical vapor deposition. Nucleation conditions were investigated for improving the growth orientation of NWs. With decreasing catalyst thickness from 5nm/5nm to 2nm/2nm, the NW orientation was improved and the NW morphology was changed from taper to cylindrical, due to the varying of growth mode. Vertical alignment of NWs can be further improved by inserting an additional high‐temperature (850 ℃) nucleation step with an optimum V/III flow ratio of 20.     

Direct Trifluoromethylthiolation and Perfluoroalkylthiolation of C(sp2)?H Bonds with CF3SO2Na and RfSO2Na

A new method for CF₃SO₂Na‐based direct trifluoromethylthiolation of C(sp²) H bonds has been developed. CF₃SSCF₃ is generated in situ from cheap and easy‐to‐handle CF₃SO₂Na, and in the presence of CuCl can be used for electrophilic trifluoromethylthiolation of indoles, pyrroles, and enamines. The method has been extended to perfluoroalkylthiolation reactions using R_fSO₂Na.     

(英)硫代氨基甲酸酯和草酰胺酯的合成、表征及抑菌活性

为发现具有农业生物活性的先导化合物,本文以三聚光气和草酸二乙酯或乙基草酰氯为酰化试剂,在不同条件下合成了硫代氨基甲酸酯和草酰胺酯或草酰苯胺酯,所有目标化合物的结构都经过质谱、1H NMR和13C NMR表征。生物活性测试表明,硫代氨基甲酸酯1b和1f在浓度为6.25 mg/L时,表现出较好的体外抑菌活性,而草酰胺酯和草酰苯胺酯没有表现出任何农业生物活性。     

有限变形时材料性质张量的选取

在有限变形时导出了用欧拉观点描述的与用拉格朗日观点描述的材料性质张量之间用矩阵形式表达的转换关系，指出正确应用这个关系时将到唯一的计算结果，与计算方法无关，建立在连续体力学中应将材料性质实验结果与欧拉观点描述的材料性质张量相对应。     

杆系结构的几何非线性分析──Ⅰ．平面问题

本文以三维连续体的虚功增量方程为基础，采用平动、转角位移分别插值的方法，导出了梁结构大位移、大转动问题内力分析的ＵＬ法。本文考虑了轴向、剪切和弯曲效应，提出了新的几何刚度矩阵。算例表明，依本文方法编制的程序具有分析结构强几何非线性行为的能力；在满足本文位移假定（即每次加载增量中转角增量是小量）的条件下，可以描述任意大角度的刚体转动。     

西安市黑河水库左坝肩渗漏三维数值模拟及坝肩坡体稳定性分析

直接针对西安市黑河水库左坝肩渗漏这一重大工程实际问题展开研究与计算。应用三维有限差分方法对左坝肩单薄山梁的初始渗流场、蓄水后的渗流场进行了数值模拟 ,分析渗漏方式、计算相应的渗漏量 ,并通过计算说明了断层是集中渗漏通道。而后利用三维数值计算提供的水位值 ,应用极限平衡分析法 ,对左坝肩岩质斜坡稳定性进行计算与分析 ,计算结果对实际工程的决策与治理提供重要的依据。     

Direct Trifluoromethylthiolation and Perfluoroalkylthiolation of C(sp2)H Bonds with CF3SO2Na and RfSO2Na

A new method for CF₃SO₂Na‐based direct trifluoromethylthiolation of C(sp²)? H bonds has been developed. CF₃SSCF₃ is generated in situ from cheap and easy‐to‐handle CF₃SO₂Na, and in the presence of CuCl can be used for electrophilic trifluoromethylthiolation of indoles, pyrroles, and enamines. The method has been extended to perfluoroalkylthiolation reactions using R_fSO₂Na.     

可见光靶源光学系统的设计与分析

飞机侦察系统性能判断是通过野外与实验室测试两种方式进行验证的。在实验室建立可见光靶源,放置在二维转台上,利用卤素灯、美军标靶源、光学系统模拟远距离目标,在规定的技术指标的基础上,设计出可见光靶源光学系统。通过光路设计、温度场分析,计算出光路束散角,设计出光阑孔,分析温度变化对光学镜片的影响,通过精密测微自准直仪检测,所有形变量均为微米级,验证了其光学设计的可靠性,满足飞机侦察系统的测试要求。     

Facile Fabrication of Monolayered Hollow Submicrospheres of PANI on Surfaces of Modified Polymer Films

Summary: A novel strategy was developed in order to prepare monolayered polyaniline (PANI) submicrospheres on polymer substrates. The strategy involved two main steps, i.e., photografting of acrylate acid (AA) onto the surface of a polypropylene (PP) film, and subsequent oxidative polymerization of aniline on the grafted surface. It was found that the PANI monolayered hollow submicrospheres were immobilized on the surface of the PP film when the molar ratio of AA to aniline was about 1:1.6. A possible formation mechanism of the hollow PANI submicrosphere iss discussed.