微孔无机膜反应器研究

主要介绍了无机膜在化学反应中的应用－－膜反应器研究，对膜反应器的特点、类型、应用、影响因素以及与其它反应器的比较进行了评述，并对其应用前景进行了展望。     

TWO-STEP MECHANISM IN HETEROGENEOUS CATALYSIS AND DYNAMIC ANALYSIS

Recent development of the dynamic analysis technique has made it possible to measure separately kinetic parameters of a catalytic reaction as well as to study the effect of catalyst preparation parameters. But its application is still limned to first-order reaction. This work is aimed to demonstrate in some detail that,by comparison of the reaction rate expressions with the two-step mechanism used in catalytic kinetics and dynamic analysis, these methods can be extended to non-first-order reaction, and the kinetic parameters measured by dynamic techniques are interpreted for different reaction mechanisms.     

湿浸法制备活性组分非均匀分布负载型催化剂过程的计算机模拟

对活性组分非均匀分布的负载型催化剂的湿浸法制备过程进行了计算机模拟,其模拟程度可适用于任意多个活性组分的浸渍。发现单组分浸渍时,通过控制浸渍时间可获得活性组分由薄到厚的蛋壳型分布和均匀分布,但通过预浸渍吸附至一定分布后,再在空白溶液中浸渍洗脱,控制洗脱条件也可获得蛋黄、蛋白型的分布;加入竞争吸附剂,进行双组分及多组分浸渍,通过控制浸渍溶液性质及浸渍时间可获得各种类型的活性组分分布,诸如蛋壳型、蛋白型、蛋黄型和均匀型。通过对制备过程参数(如竞争吸附剂的选择、各组分有效扩散系数、初始浓度、吸脱附速率常数等)与活性组分分布形式之间关系的分析,可实现对任一分布形式的催化剂的制备过程参数的优化。这对实际制备催化剂具有指导意义。     

Application potential of bone marrow mesenchymal stem cell (BMSCs) based tissue-engineering for spinal cord defect repair in rat fetuses with spina bifida aperta

Spina bifida aperta are complex congenital malformations resulting from failure of fusion in the spinal neural tube during embryogenesis. Despite surgical repair of the defect, most patients who survive with spina bifida aperta have a multiple system handicap due to neuron deficiency of the defective spinal cord. Tissue engineering has emerged as a novel treatment for replacement of lost tissue. This study evaluated the prenatal surgical approach of transplanting a chitosan–gelatin scaffold seeded with bone marrow mesenchymal stem cells (BMSCs) in the healing the defective spinal cord of rat fetuses with retinoic acid induced spina bifida aperta. Scaffold characterisation revealed the porous structure, organic and amorphous content. This biomaterial promoted the adhesion, spreading and in vitro viability of the BMSCs. After transplantation of the scaffold combined with BMSCs, the defective region of spinal cord in rat fetuses with spina bifida aperta at E20 decreased obviously under stereomicroscopy, and the skin defect almost closed in many fetuses. The transplanted BMSCs in chitosan–gelatin scaffold survived, grew and expressed markers of neural stem cells and neurons in the defective spinal cord. In addition, the biomaterial presented high biocompatibility and slow biodegradation in vivo. In conclusion, prenatal transplantation of the scaffold combined with BMSCs could treat spinal cord defect in fetuses with spina bifida aperta by the regeneration of neurons and repairmen of defective region.     

用边界轮廓法求解断裂力学L积分

证明断裂力学Ｌ积分方程的被积函数的散度等于零,将面积分转化为线积分,使求解问题的维数降低两维。利用边界轮廓法的结果,使平面断裂问题Ｌ积分的求解转化为边界点的位移和面力线性迭加,避免了求解数值积分。     

基于Softbase的Web Server分析与设计

分析了Web Server的一般结构及功能特点,设计了一种基于Softbase安全数据库系统的Web Server。     

低功耗常温CO气敏元件

采用超细SnO2粉体为材料基体，MQ-Y1元件生产工艺制成超细CO元件。在考察了工作温度、选择性、灵敏度、稳定性、响应及恢复时间等器件参数后认为，此元件可以在稍高于室温条件（25～30℃）下工作，是一种具有重要开发应用前途的气敏元件。     

Effects of temperature and pressure on stress corrosion cracking behavior of 310S stainless steel in chloride solution

310S is an austenitic stainless steel for high temperature applications, having strong resistance of oxidation, hydrogen embrittlement and corrosion. Stress corrosion cracking(SCC) is the main corrosion failure mode for 310 S stainless steel. Past researched about SCC of 310 S primarily focus on the corrosion mechanism and influence of temperature and corrosive media, but few studies concern the combined influence of temperature, pressure and chloride. For a better understanding of temperature and pressure's effects on SCC of 310 S stainless steel, prepared samples are investigated via slow strain rate tensile test(SSRT) in different temperature and pressure in NACE A solution. The result shows that the SCC sensibility indexes of 310 S stainless steel increase with the rise of temperature and reach maximum at 10 MPa and 160℃, increasing by 22.3% compared with that at 10 MPa and 80 ℃. Instead, the sensibility decreases with the pressure up. Besides, the fractures begin to transform from the ductile fracture to the brittle fracture with the increase of temperature. 310 S stainless steel has an obvious tendency of stress corrosion at 10 MPa and 160℃ and the fracture surface exists cleavage steps, river patterns and some local secondary cracks, having obvious brittle fracture characteristics. The SCC cracks initiate from inclusions and tiny pits in the matrix and propagate into the matrix along the cross section gradually until rupture. In particular, the oxygen and chloride play an important role on the SCC of 310 S stainless steel in NACE A solution. The chloride damages passivating film, causing pitting corrosion, concentrating in the cracks and accelerated SSC ultimately. The research reveals the combined influence of temperature, pressure and chloride on the SCC of 310 S, which can be a guide to the application of 310 S stainless steel in super-heater tube.     

自由液面处双悬停气泡破裂声特性研究

通过流场-声场同步测试实验,观测自由液面处双悬停气泡几近同时破裂,引起液面波动的瞬态流动行为与声学特性。利用短时傅里叶变换提取了声音信号的时-频谱图,同步分析了气泡破裂过程图像和声压图谱。结果表明,双悬停气泡相继破裂,气泡Ⅰ射流形成和气泡Ⅱ体积急剧收缩的时刻重叠,存在高于单气泡破裂0.5 Pa的声压激增现象,该声压峰值均大于单气泡破裂、体积急剧收缩、射流引起的声压幅值。双悬停气泡破裂引起的液面波动相向传播重叠时刻,也存在明显的声压峰值。其中,气泡Ⅰ射流形成和气泡Ⅱ体积急剧收缩重叠时刻的声信号中心频率约为1078 Hz;双悬停气泡破裂引起的液面振动波叠加时刻具有两个频域峰值,中心频率分别为1242 Hz和2063 Hz。     

液固体系固定床吸附器流出曲线预测模型──活性炭吸附水中酚的研究

建立了液固体系的固定床吸附预测模型,并用正交配置法获得了模型方程的数值解,实验测定了苯酚在活性炭上的静态和动态吸附数据,采用Marquadt法优化固定床吸附流出曲线数据,得到了不同浓度条件下的表面扩散系数及其变化规律,并据此预测了其他操作条件下的穿透曲线,预测曲线与实验结果相符甚好．