浅谈创业教育

按照《面向21世纪教育振兴行动计划》提出的目标，我国高等教育到2010年入学率接近15％，这个目标有可能提前实现；若按每年新出生人口为2000万计算，高等学校在校生规模将达到1500万，每年毕业生将在500万以上。面对这样沉重的就业压力，转变大学生毕业就是到社会上寻求工作岗位的就业观念，树立和加强创业教育，引导毕业生走自己的路，就显得有十分重要的特殊意义了。     

射流流化床内流体力学行为的模拟研究

以流化床应用为代表的气固流动系统是许多化工过程中的重要组成部分 ,CFD( computational fluid dynamics)方法能够为其优化设计和放大提供所需要的信息 .本文采用双欧拉模型 ,与 Gidaspow等的实验结果进行了对比 ,模拟了二维射流流化床内气泡的形成规律 ,得到了带锥型分布器的流化床内瞬时空隙率和气固相速度分布等流体力学参数 .对锥型分布器流化床的实验结果表明 ,模拟得到的气泡的形状与实验现象相接近 .     

Circulating fluidized bed combustion of a high-sulphur eastern canadian coal

Combustion tests were carried out with Minto coal in combination with three different limestones in the University of British Columbia (UBC) pilot scale (152 mm square x 7.3 m tall) circulating fluidized bed combustion (CFBC) unit. Operating conditions were chosen to be typical of those employed in large-scale CFBC power boilers. Recycling of fine particles captured by the secondary cyclone was found to be of considerable importance in increasing sulphur capture, enhancing combustion efficiency and reducing the amount of calcium sulphide in the solids residues. NO_x emissions increased as the Ca:S ratio increased. Local gas concentrations inside the reactor were strongly influenced by the core-annulus solids distribution patterns which characterize circulating fluidized beds.     

Vinyl‐containing silicone resin as the crosslinking agent of heat‐curable silicone rubber

Heat‐curable silicone rubber (HCSR) was prepared by using vinyl‐containing silicone resin (VSR) as the crosslinking agent instead of polyvinylsilicone oil (C gum). Mechanical properties and crosslink density of the vulcanizates were measured. The results indicate that VSR is a good crosslinking agent for HCSR. The tensile strength, tearing strength, elongation at break, and hardness of the vulcanizate can reach 10.2 MPa, 29.1 kN/m, 720%, and 58 SHA, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3123–3127, 2002; DOI 10.1002/app.10054     

以显微荧光检验法检测常用盖印材料

显微荧光检验法是显微检验的一个重要角度,由于缺少基础性研究,这一方法在文件检验中的运用并不广泛.着重考虑曝光时间这一因素,以盖印材料的荧光特性为观察角度,运用显微荧光检验法对大量常用盖印材料进行系统、全面的观察和研究.研究表明,绝大部分盖印材料可被激发出荧光,每种盖印材料的荧光特性都有各自的规律性特点.     

Morphologies-Controlled Synthesis and Optical Properties of Bismuth Tungstate Nanocrystals by a Low-Temperature Molten Salt Method

Well-crystallized bismuth tungstate (Bi₂WO₆) powders with different morphologies were successfully synthesized via a low-temperature molten salt method. The powders were characterized by X-ray diffraction, transmission electron microscopy, and UV-Vis, respectively. It was found that the variation of morphology of the obtained Bi₂WO₆ powder mainly depends on the different reaction temperatures and the weight ratio of LiNO₃–NaNO₃ salt to precursor. In addition, the UV-Visible absorption spectra showed that the synthesized powders had strong light absorption properties not only in the ultraviolet light but also in the visible light region.     

PPTA／尼龙1010分子复合材料流变行为的研究

本文采用共沉淀法制备了聚对苯二甲酰对苯二胺(PPTA)/尼龙1010分子复合材料。测定了PPTA/尼龙1010分子复合材料的流变行为,发现PPTA使尼龙1010的表观熔体粘度变大,且PPTA/尼龙1010分子复合材料的表观熔体粘度对温度的敏感性不象尼龙1010那样突出。     

EDTA在尿素换热设备清洗中的应用

草酸法清洗换热设备垢层时对设备腐蚀严重。EDTA能与积垢中的铁离子反应生成溶于水的络合离子,达到清洗积垢的目的,对设备腐蚀程度也小,通过EDTA、Fe含量的变化可判断清洗程度。     

聚合转化率对硫调型氯丁胶结构与性能的影响

研究了硫调型氯丁橡胶乳液聚合中转化率对产晶结构与性能的影响.结果表明,随单体转化率的提高,聚合物的凝胶量及其交联密度增大,致使断链速度减慢,所得断链胶的门尼粘度上升,残存凝胶量增加,分子支化程度增大,分子量分布变宽,焦烧时间缩短。而相应硫化胶的拉伸强度、撕裂强度、冲击弹性和硬度等提高,扯断伸长率和永久变形下降。这些变化一般在转化率为80——85％时有明显转折.综合考虑产量与质量,聚合转化率控制在82±2％较为适宜。     

Nanocrystalline CeO2 in SBA-15: Performance of Pt/CeO2/SBA-15 Catalyst for Water-gas-shift Reaction

CeO₂ particles confined within the pores of an SBA-15 mesoporous silica host were prepared by incipient wetness impregnation (IMP) and deposition precipitation (DP) methods. The materials were characterized by XRD, N₂-adsorption and temperature programmed reduction (TPR) to evaluate the structure, texture, and redox properties. The preparation procedure had significant impact on the assembling mode of CeO₂ inside the SBA-15 mesopores. A high dispersion of CeO₂ particles was achieved via DP, whereas the dispersion of CeO₂ prepared by IMP was found to be inhomogeneous and CeO₂ partially blocked the pores. The CO conversion in the water-gas-shift reaction was enhanced over 1 wt% Pt supported on CeO₂-modified SBA-15 obtained by DP.