《工程力学》新体系的探索与实践

本文郑重介绍了工程力学课程的新体系改革,在学时少的前提条件下,精简教学内容,注重基本概念讲授和适当引入计算力学新内容,重点培养学生的创新能力,增强应用所学理论解决实际工程问题的能力。     

P53反义RNA表达载体的构建

目的：针对突变型P^53基因的致癌性,采用反义RNA技术以阻断癌细胞内源突变型P^53的表达,构建真核细胞内P^53反义RNA表达载体。方法：采用定向克隆法将人野生型P^53基因cDNA反向插入到哺乳动物表达载体P^CR3.1的Ecor RⅠ和XbaⅠ位点,构建了反义P^CR3.1-P^53（AS）表达载体。结果：反义P^CR3.1-P^53(AS)表达载体构建成功。结论：此研究结果既为肿瘤发生提供理论基础,也为肿瘤基因治疗奠定基础。     

聚己内酯在有机/无机杂化体系中的受限结晶行为

通过Sol Gel技术合成了聚己内酯 (PCL) /二氧化硅 (SiO2 )杂化材料 ,并对杂化样品进行了DSC和WAXD测试 .实验结果表明杂化样品中PCL的结晶度随二氧化硅含量增加而减小 ,当样品中二氧化硅含量达到 60 %时 ,PCL为非晶态 ;含有PCL结晶的杂化样品中PCL熔融温度基本相同 ,但是比纯PCL的熔融温度低 .杂化样品中结晶PCL的结晶结构和微晶尺寸和纯PCL的一致 .这说明杂化材料中PCL的结晶行为和结晶度受到了限制 ,含PCL结晶的样品中PCL的结晶结构和微晶尺寸并没有受到影响 .     

NMR studies of the interaction betweenBacillis subtilis neutral proteinase and inorganic metal compounds

The interaction betweenBacillis subtilis neutral proteinase (B.S.NP) and inorganic metal compounds (CoCl₂, NiCl₂) was investigated by¹H NMR spectroscopy. It has been shown that the Zn(II) ion in the active center of the native enzyme may directly interact with external CoCl₂ and NiCl₂, producing Co(II)- and Ni(II)-substituted derivatives, and their¹H NMR spectra were obtained for the first time. From the¹H NMR spectra, the coordinated structure of the active center in the native enzyme was described.     

hcp结构的Co磁性膜表面和界面的非线性克尔旋转及SHG的研究

本文基于对称性理论、磁性表面的菲涅耳反射和折射定律,研究了hcp(密排六方体)Co结构的χ⁽²⁾、SHG(二次谐波振荡)信号强度和非线性磁光克尔旋转角Φ_k,α⁽²⁾与入射角、偏振角及光子能量的关系.结果表明,Φ_k,α⁽²⁾比线性克尔角有巨大的增强;当接近垂直入射时,Φ_k,α⁽²⁾接近90°;Φ_k,α⁽²⁾灵敏地依赖于M的影响,从而可以通过Φ_k,α⁽²⁾来决定薄膜中的晶轴方向和磁化强度的取向.     

提高大功率快速熔断器熔断后高温绝缘能力的物理机制

研究石英砂及粘合剂高温电阻特性 ,指出减少粘合剂中离子浓度 ,是提高保险片熔断后高温绝缘性能的关键 ,并通过试验加以验证 .     

聚琥珀酸丁二酯的辐射交联和它的热变形行为

近年来 ,塑料废弃物污染环境的问题日趋严重 .对于环境的关心 ,已经使越来越多的科研人员对于研究环境友好化合物的发展产生了极大的兴趣 .发达国家先后制订了限制或禁止某些场合使用非降解性塑料 ,因此 ,多种可生物降解性塑料已经发展起来 .目前已经商业化的可生物降解性聚合物主要有脂肪族聚酯、聚醚、聚乙烯醇和聚多糖 .其中 ,利用化学合成法开发的可生物降解性聚合物是非常重要的 .脂肪族聚酯 ,例如聚乳酸(ＰＬＡ) .聚乙二酸 (ＰＧＡ)等被广泛地用于药物的载体[1] ,聚 (ε 己内酯 ) (ＰＣＬ)也已经被用作生产生物降解性薄膜 .脂肪族聚酯…     

Probing host-selective phytotoxicity: synthesis of destruxin B and several natural analogues.

The syntheses of the host-selective phytotoxin destruxin B [cyclo(betaAla-Hmp-Pro-Ile-MeVal-MeAla), Hmp = (2R)-2-hydroxy-4-methylpentanoic acid], and the closely related natural analogues homodestruxin B (MeVal-->MeIle), desmethyldestruxin B (MeVal-->Val), hydroxydestruxin B (Hmp-->Dhmp, Dhmp = (2R)-2,4-dihydroxy-4-methylpentanoic acid), and hydroxyhomodestruxin B (MeVal-->MeIle, Hmp-->Dhmp) are described. In each case, the MeAla-betaAla linkage was formed by cyclization and the precursor linear hexadepsipeptides were formed by condensing two three-residue fragments. Radiolabeled samples of destruxin B, homodestruxin B, and hydroxydestruxin B were prepared by coupling [3-(14)C]-beta-alanine to the appropriate pentadepsipeptide followed by cyclization. A noteworthy feature of the synthesis involves the novel use of a Boc-hydrazide protecting group on dipeptides with a C-terminal N-methylalanine residue to inhibit the otherwise facile dioxopiperazine formation during peptide coupling.     

还原氧化石墨烯负载球形金属酞菁电催化阴极氧还原反应性能

针对阴极氧还原反应(ORR)动力学缓慢和Pt/C类贵金属催化剂成本高等关键难题,我们设计、合成了醛基取代的球形金属酞菁M2Pc2(TA)4(M=Zn、Co、Fe),采用"π-π组装"技术将其负载到还原氧化石墨烯(rGO)上得到复合催化剂M2Pc2(TA)4/rGO,并对其形貌和结构进行表征.结果 表明:通过"π-π堆积...     

Reduction and Oxidation Effects in Metal Oxide Catalysts

The behaviour of metal oxide catalysts in a variety of atmospheres is described. In particular the defect structures found in MoO₃ under reducing, reoxidising and mixed atmospheres are detailed. Surface relaxation defects (∼ 80 °C), surface domains (120 – 350 °C) and crystallographic shear planes (∼ 380 °C) all occur under reducing atmospheres, being differently resistant to reoxidant to reoxidation. In propylene-oxygen mixtures the CSPs appear to be unstable.