振动载荷下电路板级焊点失效信号表征及分析

针对板级焊点在振动载荷下的失效问题,搭建了具有焊点电信号监测功能的振动加速失效实验平台,在定频定幅简谐振动实验的基础上,对表征信号进行分析,通过电阻信号峰值标定焊点的失效程度.实验结果表明,焊点失效初期呈现为3个阶段,每个阶段包含电阻变化的平缓区间和陡变区间.随着3个阶段的改变,焊点低阻值区间振动循环数递减,焊点高阻值区间振动循环数递增.在此基础上,以电阻均值表征焊点平均失效程度,建立了表征焊点振动疲劳寿命的多项式模型,可以描述不同阶段焊点阻值和振动循环数的关系.     

Hydrogenation of Furfural to Furfuryl Alcohol over Co-B Amorphous Catalysts Prepared by Chemical Reduction in Variable Media

Five Co-B amorphous alloy catalysts were prepared by chemical reduction in different media, including pure water and pure ethanol as well as the mixture of ethanol and water with variable ethanol content, Their catalytic properties were evaluated using liquid phase furfural hydrogenation to furfuryl alcohol as the probe reaction. It was found that the reaction media had no significant influence on either the amorphous structure of the Co-B catalyst or the electronic interaction between metallic Co and alloying B. This could successfully account for the fact that all the as-prepared Co-B catalysts exhibited almost the same selectivity to furfuryl alcohol and the same activity per surface area （ Rs ）, which could be considered as the intrinsic activity, since the nature of active sites remained unchanged. However, the activity per gram of Co （ R^mH ） of the as-prepared Co-B catalysts increased rapidly when the ethanol content in the water-ethanol mixture used as the reaction medium for catalyst preparation increased. This could be attributed to the rapid increase in the surface area possibly owing to the presence of more oxidized boron species which could serve as a support for dispersing the Co-B amorphous alloy particles.     

聚吡咯葡萄糖氧化酶电极的生物电化学响应

采用分步骤合过程，制备了以聚吡咯膜为载体的葡萄糖氧化酶电极，探讨了其生物电化学响应特性，计算了酶催化反应的有关动力学参数。与溶解态酶相比，该电极表现出良好的生物电化学特征，而且酶蛋白对溶液温度的稳定性有显著提高。     

取代苯基呋喃甲酸长链烷基酯的合成及生物活性

取代苯基呋喃甲酸长链烷基酯的合成及生物活性司宗兴＊孙亚秋汪海涛（中国农业大学应用化学系北京１０００９４）关键词苯基呋喃甲酸酯，合成，杀菌活性１９９６－０６－１７收稿，１９９６－１２－０５修回取代芳基呋喃甲酸是一类很好的活性基团，它的酯在医学上用做镇痛...     

一种新颖1D链状聚合物[Ni(acac)2(dadpm)]∞的合成与晶体结构

The title compound [Ni(acac)₂(dadpm)]_∞ (acac=acetylacetonate, dadpm=4,4′-diaminodiphenylmethane) was synthesized from Ni(acac)₂·2H₂O with dadpm in DMF. The structure was characterized by elemental analysis, IR spectroscopy, thermal analysis and single-crystal X-ray diffraction. X-ray analysis revealed that the central Ni atom is at a center of symmetry, and is octahedrally coordinated by four O atoms from two acac anions and two N atoms from two dadpm ligands. Each dadpm ligand, which has a two-fold axis passing through its methylene C atom, bridges two Ni atoms to form a 1D polymeric chain. Neighboring chains connect via H bonding interactions to generate a 2D network. It crystallizes in the monoclinic system, space group P2/c with a=0.556 79(7), b=0.896 06(12), c=2.187 3(3) nm, β=94.942(3)°, V=1.087 2(3) nm³, Z=2, D_c=1.390 g·cm^-3, F(000)=480, M_r=455.17, μ(Mo Kα)=0.924 mm^-1, R(F)=0.036 0, wR(F²)=0.101 0, S=1.013. CCDC: 254565.     

新型链状双取代二茂铁甲酸酚酯的合成

由双取代二茂铁甲酰氯与烷基酚反应，合成了具有新型链状结构的八个二茂铁双取代衍生物。     

气体流动热量计和苯、苯-环已烷气体热容的测量

A set of vapor-flow calorimeter has been constructed on the basis of Power's adiabatic calorimeter and Clarke s flash boiler. It can determine the heat capacities of mono-or multi-component vapors from vaporizing temperature to 600 K and 10—600 kPa pressures. For the calibration of the instrument, the heat capacities of benzene have been measured under 51.1, 101.3, 309.3 and 495.2 kPa and 370—600 K tempera-tures. For multicomponent vapor, benzene-cyclohexane has been determined. The results showed that the calorimeter has both the precision and accuracy better than 1.0% for either pure or mixtural vapors.     

磷钨酸（盐）催化苯甲酸与正癸醇和鲸蜡醇酯化反应的研究

磷钨酸（盐）催化苯甲酸与正癸醇和鲸蜡醇酯化反应的研究司宗兴孙亚秋汪海涛（中国农业大学应用化学系北京１０００９４）长链化合物是一类具有广泛杀虫、杀菌和植物生长调节活性的化合物。在长链醇的酯化反应中，由于醇部分碳原子数目多，亲酯性增加，溶解度在极性溶剂中...     

改革农药有机合成教学

农药科学是化学、生物、农业等学科相互渗透的一门边缘学科。新理论、新技术在农药有机合成中不断得到应用。为此农药有机合成教学的内容也要不断更新和充实。从1984年开始我们利用假期或选修课时间开设了70学时(包括实验)的农药有机合成教学实习,实习期间有一定的时间到工厂参观学习,另外主要时间是参加农药有机合成的科研工