Double electron processes in collisions of partially stripped ions Cq+ (q=1-4) with helium

The multi-electron processes are investigated for 17.9-120keV/u C1+, 30-323 keV/u C2+, 120-438 keV/u C3+, 287-480keV/u C4+ incident on a helium target. The cross-section ratios of double electron (DE) process to the total of the single electron (SE) and the double electron process (i.e. SE+DE), the direct double electron (DDI) to the direct single ionization (DSI) as well as the contributions of DDI to DE and of TI to DE are measured using coincidence techniques. The energy and charge state dependences of the measured cross-section ratios are studied and discussed.

均相钕系催化剂合成窄相对分子质量分布的高顺式-1，4-聚丁二烯

考察了由Nd（vers）3（简称Nd）、Al（i—Bu）2H（简称Al）和Al（i—Bu）2Cl（简称Cl）组成的均相催化剂体系在5L釜中于70℃聚合丁二烯的反应规律，并在2m^3装置上进行了放大试验。结果表明，该均相钕系催化剂具有高的稳定性；Al／Nd（摩尔比）是影响相对分子质量分布的重要因素，当Al／Nd低于20时，产物的相对分子质量分布在3．00以下；改变Nd／Bd（摩尔比）或使用不同组成的Al，可改变聚合产物的门尼黏度，但对相对分子质量分布无明显影响。在2m^3装置上，采用均相钕系催化剂可以得到收率大于90％、相对分子质量分布小于3.00和顺式-1，4-结构摩尔分数大于97．0％的聚丁二烯

Hole-transporting polymers containing carbazol-3,9-diyl and 1,4-phenylene fragments in the main chain

New carbazole-based polymers, which contain various content of electro-active fragments in the main chain connected via alkylene spacers, have been synthesized by Ni(0)-catalyzed Yamamoto-type aryl-aryl coupling reactions. These compounds represent amorphous materials of high thermal stability with glass-transition temperatures of 139-151 degrees C and thermal decomposition starting at temperatures above 400 degrees C. UV-vis absorption and photoluminescence emission spectra of the materials confirmed that the conjugated segments in the macromolecules are rather short.

Length dependence of electron conduction for oligo(1,4-phenylene ethynylene)s: A conductive probe-atomic force microscopy investigation

The dependence of electron conduction of oligo(1,4-phenylene ethynylene)s (OPEs) on length, terminal group, and main chain structure was examined by conductive probe-atomic force microscopy (CP-AFM) via a metal substrate-molecular wire monolayer-conductive probe junction. The electron transport in the molecular junction was a highest occupied molecule orbital (HOMO)-mediated process following a coherent, non-resonant tunneling mechanism represented by the Simmons equation.

反式1,4-聚丁二烯的非等温结晶动力学研究

采用Nd(P507)3 LiBu AlEt3和AlEt3 VCl3两种催化剂体系分别合成了两种分子量与反式1,4单元结构含量不同的反式1,4 聚丁二烯样品(TPBD)。用DSC方法不仅研究了两样品六方相晶体的非等温结晶过程,同时还对单斜相结晶的非等温动力学过程进行了研究。Avrami方程分析显示,在低结晶度下TPBD六方相和单斜相的结晶生长过程呈现热成核的三维球晶生长。研究表明:虽然Ozawa方程在较低温度下能描述TPBD的六方相结构的实验数据,但不能完全描述在较高温度下六方相及单斜相非等温结晶过程,而用莫志深等建议的方程则能很好地描述TPBD六方相和单斜相非等温结晶过程。由Kissinger方程得到TPBD六方相和单斜相结晶的平均结晶活化能分别为-165.8kJ/mol和-220.5kJ/mol。

一种1,4-丁二醇脱氢制备γ-丁内酯催化剂及其用途

一种１，４－丁二醇脱氢制备γ－丁内酯催化剂，其各组份重量百分比为：ＣｕＯ４８－５５％；ＺｎＯ４２－５０％；Ｃｅ↓［２］Ｏ↓［３］２－３％。催化剂在１，４－丁二醇脱氢制备γ－丁内酯应用先在氢气气氛中还原活化，然后装入固定床反应器内，反应温度２１０－２６０℃，反应压力小于０．０５ＭＰａ，液体空速０．１－０．７ｈｒ↑［－１］。本发明催化剂具有较高的活性，１，４－丁二醇转化率大于９８％，γ－丁内酯选择性大于９５％，催化剂中不含Ｃｒ的优点。