用稀土金属铽的有机配合物Tb(acac)2(AA)phen做发光层的电致发光薄膜的研究

研究了稀土铽的有机配合物(Tb(acac)2(AA)phen的光致发光特性,用Tb(acac)₂(AA)phen做发光层,分别用N,N’-双(3-甲苯)-N,N’-二苯联苯胺(TPD)和聚乙烯基咔唑(PVK)做空穴传输层研制了有机电致发光薄膜器件,研究了它们的电致发光特性.     

2'-hydroxyl proton positions in helical RNA from simultaneously measured heteronuclear scalar couplings and NOEs

The 2'-hydroxyl group in RNA plays an important structural role; it defines hydration in the minor groove, impacts thermodynamic stability of RNA, and often participates in RNA catalysis. To better study this important functional group in RNA, we describe a constant-time HMQC-IPAP-NOESY 3D NMR experiment. It simultaneously yields highly resolved 13C-separated NOEs from ribose protons to the 2'OH proton, as well as E.COSY-type measurement of JC-OH couplings, thereby permitting a quantitative study of the orientation of the 2'OH proton in RNA. The observed NOE patterns indicate that the 2'OH bonds in A-form helical RNA are primarily oriented toward the base domain, as further supported by small (1.3 +/- 0.7 Hz) 3JC1'-2'OH and relatively large (4.2 +/- 0.7 Hz) 3JC3'-2'OH couplings. The constant-time HMQC-IPAP-NOESY is suitable for measurement of interactions of rapidly exchanging protons in proteins and nucleic acids.     

现代质谱及其联用技术在抗癌药物研究中的应用

综述了质谱及其联用技术(如气相色谱-质谱,液相色谱-质谱,毛细管电泳-质谱等)在抗癌药物的分离鉴定、药物代谢产物的研究及药物作用机理方面的应用,总结了其发展潜力。     

垂直定向液晶光阀中液晶电光特性的理论分析

采用 ４×４ 矩阵法模拟计算了垂直定向液晶光阀的电光特性, 从理论上分析了影响液晶光阀电光特性的因素。根据向列液晶的弹性连续体理论及边界力矩平衡方程, 求出了垂直定向向列液晶在液晶界面之间相互作用锚泊能为有限值时的液晶指向矢分布。根据指向矢分布计算了一定外加电场下液晶光阀的电光特性, 并和锚泊能为无限大时的特性进行了比较和分析     

用铜和氯掺杂的CdS-CdSe双层光电导膜的性质

对掺Ｃｕ和Ｃｌ的ＣｄＳ－ＣｄＳｅ双怪光电导膜的暗电导和亮电导与掺杂浓度及Ｃｕ／Ｃｌ比的关系、响应时间和光谱响应进行了研究。试验发现：适当的Ｃｕ／Ｃｌ掺杂比可使暗电导降低而亮电导提高;掺杂薄膜的响应时间可达５－１０ｍｓ,而对掺杂一般为数百毫秒;随着ＣｄＳｅ浓度增加,光学吸收变大,光谱响应向长波移动 。     

Synthesis of 5′,9-anhydro-3-(β-d-ribofuranosyl)xanthine, and 3,5′-anhydro-xanthosine as potential anti-hepatitis C virus agents

5′,9-Anhydro-3-(β-d-ribofuranosyl)xanthine and 3,5′-anhydro-xanthosine were prepared as potential anti-hepatitis C virus (HCV) agents from uridine and xanthosine, respectively.     

Stereoselective synthesis of novel dipeptide beta-turn mimetics targeting melanocortin peptide receptors

[reaction: see text] The novel dipeptide beta-turn mimetic, 4,8-disubstituted azabicyclo[4.3.0]nonane amino acid ester (15), has been synthesized to serve as a peptide mimetic of the dipeptide Phe-Arg, which contains two important pharmacophore elements in melanotropin peptides. Introduction of side-chain functionality at C-8 was achieved by using beta-functionalized pyroglutamate (8) as a synthetic precursor. The side chain at C-4 was introduced by bromination of dehydroamino acid intermediate (10) followed by Suzuki cross-coupling.     

Pedagogical representations to teach linear relations in Chinese and U.S. classrooms: Parallel or hierarchical?

This study investigates Chinese and U.S. teachers’ construction and use of pedagogical representations surrounding implementation of mathematical tasks. It does this by analyzing video-taped lessons from the Learner's Perspective Study, involving 15 Chinese and 10 U.S. consecutive lessons on the topic of linear equations/linear relations. We examined patterns of pedagogical representations that Chinese and U.S. teachers construct over a set of consecutive lessons, but also investigated the strategies of using representations to solve mathematical problems by Chinese and U.S. teachers. It was found that multiple representations were constructed simultaneously to develop the connection of relevant concepts in the U.S. classrooms while selective representations were constructed to develop relevant concepts in the Chinese classrooms. This study is significant because it contributes to our understanding of the cultural differences involving Chinese and U.S. students’ mathematical thinking and has practical implications for constructing pedagogical representations to maximize students’ learning.