吸收剂量对二甲基硅橡胶与甲基乙烯基硅橡胶分子量和凝胶含量的影响

将ＧＰＣ和特性粘数［η］测定相结合，在室温和－７８℃下，用Ｃｏ~（６０）辐射源辐照，研究了二甲基硅橡胶（ＭＱ，吸收剂量２．０５×１０~３～３．９７×１０~４Ｇｙ）和甲基乙烯基硅橡胶（ＭＶＱ，吸收剂量１０~２～１０~４）分子量和凝胶含量的变化。结果表明，辐照ＭＶＱ较辐照ＭＱ易生成凝胶，在凝胶点前的较低吸收剂量时，溶胶的分子量出现极大值，分子量分布曲线呈单峰；随吸收剂量的增加，分子量分布变窄，分子量降低；出现凝胶的吸收剂量，ＭＱ大约是ＭＶＱ的１０倍。辐照ＭＱ时，凝胶点前的溶胶的分子量分布曲线为双峰，并随吸收剂量的增加，双峰消失，分子量下降；在凝胶点时，分子量出现极大值。     

氟化铵溶解含氟硅渣制备氟硅酸铵的实验研究

以氟化铵溶液和含氟硅渣为原料,通过化学溶解的方式,制备氟硅酸铵产品。考察了反应温度、反应时间、氟化铵溶液浓度和物料配比（氟化铵与二氧化硅的物质的量比）等不同工艺条件对氟硅酸铵收率、二氧化硅转化率的影响。实验结果表明：反应温度为93 ℃、反应时间为60 min、氟化铵溶液质量分数为20%~30%、物料配比为6∶1.1、反应体系搅拌速度为200~300 r/min时,氟硅酸铵的收率和氟化铵的转化率可控制在90%以上。     

削弱或抑制抗氧剂、光稳定剂作用的有关因素

介绍了削弱或抑制抗氧剂、光稳定剂作用的常见因素及实例，分析了防老化塑料制品发生提前老化现象的可能性和原因。     

IT认证与专业课程相适应的教学研究

随着信息技术的高速发展,IT行业人才的需求与培养成为高校教学改革面临热点问题.本文分析了传统的人才培养模式改革的必要性.通过调整专业课程体系,使IT职业认证与专业课程相适应,开创新的人才培养模式把学生培养成为高素质的技术应用型人才,从而满足市场需求.     

Preparation and modification of macroporous epoxy‐triethylenetetramine resin for preconcentration and removal of Hg(II) in aqueous solution

A novel macroporous resin was prepared from epoxy resin and triethylenetetramine through a polymerization with phase separation. In this experiment, the polyethylene glycol (PEG‐1000) plays a very important part. It was used as solvent, as phase‐separation reagent in the preparation processes, and as the pore‐forming reagent through removing PEG‐1000 from polymer by water‐cleaning process after completing polymerization. The prepared resin was modified by carbon bisulfide and soaked in 1 mol L^?1 NaOH. Its structure was characterized by Fourier transform‐infrared spectra, scanning electron microscopy, and elemental analysis. The adsorption characteristic of the chelating resin was studied by series of experiments. The results show that the chelating resin possesses excellent adsorption characteristic toward trace Hg(II). The recovery can come to 100% when the concentration of Hg(II) is only 0.05 ppm, and the average maximum adsorption capacity of the chelating resin for Hg(II) is 122 mg g^?1. The precision (relative standard deviation) for six replicate adsorbent extraction of 0.01 μg mL^?1 Hg(II) was 1.1%. The accuracy of the proposed procedure was verified by analyzing a standard reference material. Moreover, the chelating resin was applied to two natural samples and also got satisfactory results. That is to say, the chelating resin modified by carbon bisulfide exhibits a high chelating ability toward Hg(II) and can be used as adsorbent for preconcentration and removal of trace Hg(II) in aqueous solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2372–2378, 2006     

Preparation and characterization of amphiphilic block copolymer of polyacrylonitrile‐block‐poly(ethylene oxide)

The synthesis of polyacrylonitrile‐block‐poly(ethylene oxide) (PAN‐b‐PEO) diblock copolymers is conducted by sequential initiation and Ce(IV) redox polymerization using amino‐alcohol as the parent compound. In the first step, amino‐alcohol potassium with a protected amine group initiates the polymerization of ethylene oxide (EO) to yield poly(ethylene oxide) (PEO) with an amine end group (PEO‐NH₂), which is used to synthesize a PAN‐b‐PEO diblock copolymer with Ce(IV) that takes place in the redox initiation system. A PAN‐poly(ethylene glycol)‐PAN (PAN‐PEG‐PAN) triblock copolymer is prepared by the same redox system consisting of ceric ions and PEG in an aqueous medium. The structure of the copolymer is characterized in detail by GPC, IR, ¹H‐NMR, DSC, and X‐ray diffraction. The propagation of the PAN chain is dependent on the molecular weight and concentration of the PEO prepolymer. The crystallization of the PAN and PEO block is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1753–1759, 2003     

MgO－B_2O_3－SiO_2系晶化分形的计算机模拟

采用两段热处理技术，利用Ｘ射线衍射分析、扫描电镜观察等方法研究广２ＭｇＯ－Ｂ＿２Ｏ＿３－ＳｉＯ＿２系的晶化过程，晶化析出相２ＭｇＯ·Ｂ＿２Ｏ＿３的微观形貌具有分形特征，采用密度－密度相关函数法计算其分形维数为１．６３。为揭示２ＭｇＯ·Ｂ＿２Ｏ＿３生长机制，采用Ｍｏｎｔｅ－Ｃａｒｌｏ方法及改进的ＤＬＡ模型对分形生长过程进入计算机模拟。模拟结果与实际分形结构、分形维数相符，表明２ＭｇＯ·Ｂ＿２Ｏ＿３生长是扩散控制凝聚过程。可以预见，分形理论与计算机模拟相结合，将会在探讨未知机理方面发挥重要作用。     

Wear behavior of <Emphasis Type="Italic">in-situ</Emphasis> TiC particles reinforced aluminum matrix composite

The microstructure, tensile property and wear resistance of 7075 aluminum matrix composite reinforced with TiC particles prepared by in-situ reaction casting were investigated. The effect of TiC reinforcement on wear behavior was analyzed. The wear mechanism was also discussed. A micro-mechanism model of reaction kinetics for synthesis of TiC was acquired. Results show that TiC could increase the tensile and yield strength, but decrease the elongation. Besides, TiC particles improve the property of wear resistance of 7075 aluminum alloy. The wear mechanisms include abrasive wear and adhesive wear in wear test process.     

基于风环境模拟与优化的滨海居住区规划设计

目的研究居住区规划中风环境对人体舒适度和绿地释氧的影响,并以此优化园区空间布局.方法将风环境模拟技术引入滨海居住区的规划设计中,基于CFD(计算流体力学)模型,应用AIRPARK软件对居住区的风环境进行模拟与分析,并模拟了与建筑物呈不同夹角风向下的绿地释放氧气的扩散范围.结果夏季,能够充分利用风压差,排除整体余热,实现自然通风的冷却效应;冬季,高层建筑有效地阻挡了东北方向冷风侵入,降低通过风的强度与速度,使居住区内的风环境达到相对舒适状态.在局部风场的影响下,居住区实际的绿地位置与其释放氧气的扩散范围存在空间差异性.结论风环境预测提高了城市空间规划布局的科学性,对降低可吸入颗粒物扩散、缓解城市热岛效应、提升城市空间环境质量具有重要意义.     

微/纳米ZnO绒球的制备及对混合污水的光降解

以自制的谷氨酸-氟硼酸(GluBF4)离子液体水溶液为反应介质,以物质的量比为1∶6的二水合醋酸锌[Zn(Ac)2·2H2O]和NaOH为原料,室温(25℃,20min)制备前驱体,再微波辅助加热(80℃,10min)制备了纳米氧化锌粉体,获得了纳米结构微米尺寸ZnO绒球。利用场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)、比表面积(BET)、能谱(EDS)等对产物进行了表征。结果表明,所得产物为六方晶系纤锌矿结构,粉体粒径20.4nm,绒球比表面积为27.6m2/g。该纳米材料具有较高的光催化降解有机污染物活性。以紫外光为光源,50 mg微/纳米ZnO绒球为光降解催化剂,取500mL北京雪莲羊绒股份有限公司排污口混合印染污水进行光降解实验,在30min内光降解效率达到了100%,催化剂可回收重复利用,并对光降解机理进行了初步分析。