纳米混合分子聚集体材料中弗兰克尔激子迁移的相位弛豫

在有机染料ＰＩＣ－１中引入其衍生物ａｚａＰＩＣ－Ｉ形成能量势垒，改变在混合分子聚集体中ＰＩＣ－Ｉ的Ｊ－聚集体的实体长度。用双调制外差检测的累积光子回波技术研究了相干弗兰克尔激子失相过程。观测到激子失相时间Ｔ２随ａｚａＰＩＣ－１克分子数的增大从６０ｐｓ变为２２４ｐｓ。     

Alkylation de la dimethyl-5 5′ isoxazolidinone-3 en catalyse par transfert de phase

Alkylation by phase transfert catalysis of ambidents anions of the N-C-0 type, leads to a mixture of N and O substitution. Isomers per cent are 20% for O alkylation and 80% for N alkylation when primary halides are used. With secondary halides, these figures are 35% and 65%. In both cases the overall yield ranges around 60%.     

共价键相联的卟啉-酞菁激发态性质——(Ⅱ)非线性光学性质研究

卟啉(TTP)和酞菁(Pc)分子表现出反饱和吸收特性,而在卟啉和酞菁二元分子TTP-O-Pc和TTP-O-(CH₂)_s-O-Pc中反饱和吸收现象消失。简并四波混频(DFWM)方法用于测量兰阶非线性光学极化率X⁽³⁾,二元分子比单元分子的X⁽³⁾提高了10²倍以上,达到3×10^-9esu。     

Hydrolysis of 1-methyl-2-methylthio-Δ2-imidazoline

New results in SN methyl transfer reaction in the series of Δ₂-imidazoline with and without quaternary salt catalyst are reported. The hydrolysis of monocyclic compounds containing the 2-alkyl thio, uronium group leads to the formation of a salt. Rearrangement reactions observed in the “uncatalysed reaction” may be due to a true catalytic reaction.     

S-Alkylation en série hétérocyclique par catalyse par transfert de phase: thioalkyl-2-thiazoles,thioalkyl-2-Δ-4-thiazolines et thioalkyl-2-benzothiazoles

S-Alkylation in heterocyclic serie by phase transfer catalysis: 2-alkylthiothiazoles, 2-alkylthio-Δ-4-thiazolines and 2-alkylthiobenzothiazoles Some Δ-4-thiazoline-, thiazolidine-, and benzothiazoline-2-thiones have been S-alkylated by phase transfer catalysis; yields averaged 80 to 90%. With halogenated heterocyclic compounds of poor reactivity, the main reaction consisted in a dequaternization of the catalyst by the thiones acting as nucleophiles.     

电场调谐InAs单量子点的发光光谱

采用稳态和时间分辨发光光谱,研究了生长在p-i-n二极管结构内的InAs单量子点发光光谱的电场调谐特性.随着电场强度的增加,观察到量子点中激子发光的Stark 效应.通过选择不同波长的激光线激发量子点样品,发现随着电场强度的增加导致量子点发光强度的减弱,这是由于量子点俘获载流子概率的减小所致,而激子寿命的增加源于电场导致激子的Stark效应. 关键词： InAs单量子点 Stark效应 电子-空穴分离     

三效吸收式制冷循环系统性能分析

对12个通用的三效循环系统以及这12个通用循环系统组成的76种可能的密闭循环系统进行了评测。根据通用三效循环系统的压力和溶解度要求,对通用三效循环系统进行了分析,并充分考虑各部件设计中的问题和COPs数值,以及处于高腐蚀环境中部件的数目。通过分析,确定了四个性价比较优的系统:Alkitrate Topping循环系统,Pressure Staged Envelope循环系统,High Overlap循环系统和Dual Loop循环系统。     

Structure of Reconstructed Cu(100) Surface Induced by Dissociative Adsorption of Gaseous Oxygen

用低能电子衍射(LEED)和扫描隧道显微镜技术研究了氧气在Cu(100)表面化学吸附所形成的表面重构结构．在低覆盖度下,实验上观察到了两个有序重构的混合相,分别为c(2×2)O重构和(√2×2√2)R45°-O重构．在氧原子的覆盖度逐渐增加的过程中,c(2×2)O重构区域的面积逐渐减小．在初始氧化阶段,实验上观察到了呈条状的“锯齿”形的重构结构,这些锯齿形的结构是由相邻的局域化的c(2×2)区域的边界区域(Cu)构成的．STM实验发现,相对于其他重构区域,这些锯齿形的重构区域与有机分子之间存在更加强烈的相互作用．通过分析在不同退火温度下样品LEED衍射点的变化,研究了重构结构的热稳定性,发现三种结构的热稳定性顺序是：锯齿结构>c(2×2)O重构>(√2×2√2)R45°-O重构．