Direct synthesis of ordered N-methylimidazolium functionalized mesoporous silica as highly efficient anion exchanger of Cr(VI)

Ordered N-methylimidazolium functionalized mesoporous silica (SBA-15) anion exchangers were directly synthesized by co-condensation of tetraethoxysilane with 1-methyl-3(triethoxysilylpropyl)imidazolium chloride. The prepared samples with rod-like morphology showed high surface areas (> 400 m(2) g(-1)), well-ordered pores (> 58 angstrom), and excellent thermal stability up to 387 degrees C. The adsorption behaviors of Cr(VI) from aqueous solution on the anion exchangers were studied using the batch method. The anion exchangers had high adsorption capacity ranging from 50.8 to 90.5 mg g(-1), over a wider pH range (1-8) than amino functionalized mesoporous silica. The adsorption rate was fast, and the maximum adsorption was obtained at pH 4.6. The adsorption data for the anion exchangers were consistent with the Langmuir isotherm equation. Most active sites of the anion exchangers were easily accessible. The mixed solution of 0.1 mol L-1 NH3 center dot H2O and 0.5 mol L-1 NH4Cl was effective desorption solution, and 95% of Cr(VI) could be desorbed.

Analysis of chemical calorific effect during reactive extrusion processes for free radical polymerization

In the reactive extrusion process for polymerization, the chemical calorific effect has a great influence on the temperature. In order to quantitatively analyze the polymerization trend and optimize the processing conditions, the phenomena of the chemical calorific effect during reactive extrusion processes for free radical polymerization were analyzed. Numerical computation expressions of the heat of chemical reaction and the reactive calorific intensity were deduced, and then a numerical simulation of the reactive extrusion process for the polymerization of n-butyl methacrylate was carried out. The evolutions of the heat of chemical reaction and the reactive calorific intensity along the! axial direction of the extruder are presented, on the basis of which reactive processing conditions can be optimized.

LIFETIMES OF RYDBERG LEVELS IN THE PERTURBED 6SNP 3P2 SERIES OF YTTERBIUM-I

Using three-step laser excitation in an atomic beam and a time-resolved spectroscopy technique, we measured both the lifetimes of the Rydberg levels of Yb I belonging to the perturbed series 6nsp 3P2 and the lifetimes of the perturbing 4f(13)5d(2)6s 3P2, 1D2 levels. An expected shortening has been observed for the lifetimes of those levels which are strongly mixed with the perturbers.

新型双碳桥联二环戊二烯基稀土氯化物的合成与表征

桥联双环戊二烯基稀土化合物的合成已有不少报道。但双碳桥联双环戊二烯基稀土化合物至今未见任何报道。我们以(CH_3)_4C_2(C_5H_4MgCl)_2·4THF(Ⅰ)与无水三氯化稀土反应,通过控制两者的比例合成了两类双碳桥联二环戊二烯基稀土氯化物,(CH_3)_4C_2(C_5H_4)_2LnCl_2·Mg_2Cl_3·nTHF(Ⅱ)和(CH_3)_4C_2(C_5H_4LnCl_2·MgCl_2)_2·nTHF(Ⅲ),并对这两类化合物进行了表征,证实了这两类化合物的存在。

Substrate induction and statistical optimization for the production of chitosanase from Microbacterium sp OU01

The chitosanase production was markedly enhanced by substrate induction, statistical optimization of medium composition and culture conditions by Microbacteritan sp. OU01 in shake-flask. A significant influence of (NH4)(2)SO4, MgSO4 center dot 7H(2)O and initial pH on chitosanase production was noted with Plackett-Burman design. It was then revealed with the method of steepest ascent and response surface methodology (RSM) that 19.0 g/L (NH4)(2)SO4, 1.3 g/L MgSO4 and an initial pH of 2.0 were optimum for the production of chitosanase; colloidal chitosan appeared to be the best inducer for chitosanase production by Microbacterium sp. OU01. This optimization strategy led to the enhancement of chitosanase from 3.6 U/mL to 118 U/mL. (c) 2006 Elsevier Ltd. All rights reserved.

发挥自身优势 不断改革进取

沈阳自动化所按照自身发展的指导方针,不断改革内部机制,进行结构性调整,完善组织管理措施;以市场为导向,把握时机大胆开拓;加强与企业的联系,争取地方支持,多年来一直保持着上升的趋势,凝聚了队伍,也为国家作出了贡献。

CIMS环境下单元的柔性计划生产方法

本文研究了ＣＩＭＳ环境下的生产计划问题．考虑了两种市场需求驱动生产方式，一种是在计划周期内各阶段市场需求由预先订货决定，另一种是市场需求不是由预先订货决定，而是一个随机变量．但可根据统计，确认它服从某种分布规律，对于这两种生产方式，本文可给出最优的生产计划。

岩溶区红色风化壳物源示踪的有效方法——粒度分析

在低纬度的热带、亚热带岩溶地区 ,水热条件充沛 ,广泛发育着厚度不一的红色风化壳。由于碳酸盐岩易溶蚀 ,酸不溶物含量低 ,同时宏观上风化壳和下伏基岩呈突变接触 ,风化壳中原岩的残余结构消失 ,在野外缺乏直接的地质证据支持两者之间存在着一定的演化关系 ,所以这些岩溶区红色风化壳的物质来源长期以来一直存在着争议。而物质来源的准确识别是进行这些风化壳机理研究的基础和关键。笔者在对贵州岩溶台地红色风化壳的研究过程中 ,尝试通过粒度分析 ,来探讨风化壳的物质来源和演化特征。在不同环境背景下 ,沉积物的粒度分布特征是不同的。因此在不同沉积岩 (物 )上发育的风化壳就会继承母岩的这种粒度特征 ,如果风化壳的成土母岩来源于碳酸盐岩 ,那么就会继承碳酸盐岩酸不溶

华南晚震旦世陡山沱组有机碳同位素地球化学研究

晚震旦世扬子地台陡山沱组地层出露较好，沉积环境多变，由浅水区的台地相向深水区的盆地相变化，是最重要的成磷期之一。地层中有著名的“帽”碳酸盐岩沉积和瓮安生物群产出。本研究展示了来自以下几个剖面沉积岩的碳酸盐和与之共生的有机质碳同位素组成：台地相区的贵州瓮安剖面，过渡相区的贵州松桃剖面和南明剖面，盆地相区的湖南岩屋滩剖面。主要是分析和探讨该时期扬子地台的生命演化过程和环境变化的关系。从南沱组到陡山沱组.