Luminescence properties of the Langmuir-Blodgett film of terbium(III) stearoylanthranilate

Terbium(III) stearoylanthranilate has been prepared as a high property Z-type Langmuir-Blodgett (LB) film on various substrates by a vertical transfer process. The UV-visible absorption spectra and the low angle X-ray diffraction peaks have been collected in order to investigate the molecular arrangement and aggregation in the LB films. The average molecular orientation in multilayer stacking was determined by Attenuated Total Reflection Spectroscopy. The influence of the chemical environment of terbium within the LB films on the luminescence properties has been discussed. (C) 1997 Elsevier Science S.A.

In situ electrochemical scanning tunnelling microscopy investigation of structure for horseradish peroxidase and its electrocatalytic property

Immobilization of protein molecules is a fundamental problem for scanning tunnelling microscopy (STM) measurements with high resolution. In this paper, an electrochemical method has been proved to be an effective way to fix native horseradish peroxidase (HRP) as well as inactivated HRP from electrolyte onto a highly oriented pyrolytic graphite (HOPG) surface. This preparation is suitable for both ex situ and in situ electrochemical STM (ECSTM) measurements. In situ STM has been successfully employed to observe totally different structures of HRP in three typical cases: (1) in situ ECSTM reveals an oval-shaped pattern for a single molecule in neutral buffer solution, which is in good agreement with the dimension determined as 6.2 x 4.3 x 1.2. nm(3) by ex situ STM for native HRP; (2) in situ ECSTM shows that the adsorbed HRP molecules on HOPG in a denatured environment exhibit swelling globes at the beginning and then change into a V-shaped pattern after 30 min; (3) in situ ECSTM reveals a black hole in every ellipsoidal sphere for inactivated HRP in strong alkali solution. The cyclic voltammetry results indicate that the adsorbed native HRP can directly catalyse the reduction of hydrogen peroxide, demonstrating that a direct electron transfer reduction occurred between the enzyme and HOPG electrode, whereas the corresponding cyclic voltammograms for denatured HRP and inactivated HRP adsorbed on HOPG electrodes indicate a lack of ability to catalyse H2O2 reduction, which confirms that the HRP molecules lost their biological activity. Obviously, electrochemical results powerfully support in situ STM observations.

氯代甲苯异构体双电荷离子电子捕获诱导解离谱研究

研究了４种Ｃ７Ｈ７Ｃｌ异构体在７０ｅＶ电子轰击下产生的［Ｃ７Ｈ７Ｃｌ］（２＋）、［Ｃ７Ｈ６Ｃｌ］（２＋）和［Ｃ７Ｈ５Ｃｌ］（２＋）３种双电荷离子的电子捕获诱导解离（ＥＣＩＤ）反应。分子离子的ＥＣＩＤ反应有明显的邻位效应，表明其结构仍保持中性分子的结构特征；而由各异构体产生的［Ｃ７Ｈ６Ｃｌ］（２＋）和［Ｃ７Ｈ５Ｃｌ］（２＋）离子异构化成同一结构。３种双电荷离子ＥＣＩＤ反应的产物与离子所带电子的奇偶性有关，无论是奇电子离子还是偶电子离子，其解离产物多为偶电子离子。

偶联剂对阻燃型高抗冲聚苯乙烯性能的影响

在阻燃型高抗冲聚苯乙烯（ＨＩＰＳ）中，加入一定量的ＳｉＯ２作为填充剂。采用偶联剂对无机填料进行表面处理，改善了ＨＩＰＳ与无机填料的界面结构。用电子显微镜观察了无机填料表面处理前后的形态变化。

高效反渗透复合膜研究──高分子合金微孔底膜的制备与性能

研究了含酞基聚芳醚酮（ＰＥＫ－Ｃ）与聚砚（ＰＳｆ）的组成比例、添加剂和磺化处理对ＰＥＫＣ—ＰＳｆ合金不对称微孔底膜的成膜与性能的影响规律，其中适当的聚合物的组成、混合添加剂可使底膜水透量有一最大值；无机辅助添加剂及其膜表面非均相磺化处理可使底膜的水通量增大，从而制得了具有一定结构性能特点的新型高分子合金底膜。

NdC_6H_6(AlCl_4)_3-AlR_3体系对丁二烯与异戊二烯的共聚合

报道了NdC_6H_6(AlCl_4)_3-AlR_3体系催化丁二烯与异戊二烯共聚反应的一般规律。催化活性依赖于两种单体的配比、单体浓度、烷基铝性质及聚合温度。制得的双烯共聚物具有高1,4链节结构。

Li_2S-SiS_2-LiBO_2-LiCl体系玻璃的XPS表征

本文采用光电子能谱分析方法,首次研究Li_2S-SiS_2-LiBO_2-LiCl体系硫氧化物玻璃锂离子导体的组成、结构和状态。指出在该玻璃体系中,除与硅(硼)相键合的桥硫存在外,还有不与硅(硼)相键合的非桥硫存在;玻璃中的硫取代了氧的位置,进入玻璃网络中使结构紧密交联。对网络中的元素状态,成键及性能进行了讨论。

硝酸镧与冠醚(2,2)配合物的晶体及电子结构研究

用X-射线单晶衍射法测定了硝酸镧与冠醚(2,2)配合物的晶体结构,发现其具有与报道的Eu(NO_3)_3(2,2)配合物不同的配位方式.晶体属于三斜晶系,空间群P(?),晶胞参数为a=10.312(2)(?);b=12.745(3)(?);c=8.917(2)(?);α=103.79(2)°;β=112.73(2)°;γ=83.68(2)°;V=1049.5(5)(?)~3;F(000)=587.88;Z=2.结构用重原子法解出;R值为0.0292.用INDO法计算了配合物的净电荷分布,电子结构、键级.结果表明,镧与配位原子间的键具有一定程度的共价性.镧的5d轨道对共价性的贡献最大,而4f轨道基本上不参与成键.La-N比La-O(醚)间存在较强的作用,增大了配合物的稳定性.

CaS:Cu~+磷光体的合成及发光性质

本文首先用X光电子能谱分析铜在硫化钙基质中是以一价形式存在的.在掺铜的硫化钙的激发光谱中,有三个吸收峰,峰位分别为268nm、307nm和400nm;在CaS:Cu~+的发射光谱中,产生四个发射峰,峰位分别为430nm、465nm、490nm和610nm.这四个发射峰分别由不同铜离子格位产生的.在Cas:Cu~+的热释发光曲线中,显示单一热释发光峰,峰值温度为120℃,该热释发光峰有可能用作紫外剂量材料.

载体钒氧化物中钒-吸附物分子相互作用的ESR研究

电子自旋共振技术已经用来研究还原态V_2O_5/SiO_2催化剂和各种吸附分子的相互作用。实验指出:具有四面体配位结构的V~(4+)离子是活性中心,V~(4+)和CH_2OH,HCl,CH_3CN分子的相互作用导致形成八面体配位结构的表面VO~(2+)络合物,它们的ESR和成键参数计算指出不成对电子主要定位在钒离子的d轨道上。77 K下吸附O_2分子已经观察到氧自由基的ESR信号,但吸附乙烯和丙烯不能改变V~(4+)离子的配位结构。

Er_xY_(1-x)AlO_3晶体的荧光动力学研究

本文详细计算了辐射跃迁几率、无辐射跃迁几率、交叉弛豫几率和其他光谱参数。并且在考虑上述三种辐射过程的情况下,讨论了Er~(3+)离子的荧光动力学过程,研究了荧光发射特征与Er~(3+)离子浓度的关系,给出了它们的规律。

多层结构半导体膜的XPS和AES分析

本文采用VG ESCALAB MK-Ⅱ电子能谱仪对多层结构的薄膜Cu_2S-CdS太阳电池进行了X-光电子能谱、俄歇电子谱和深度分析。指出了电池表面的组成、结构和状态。由于制备工艺和处理方法的不同,电池表面和界面会发生变化,从而影响薄膜Cu_2S-CdS太阳电池的电性能和稳定性。本文为电池机理的研究提供了一些数据。