两种人工湿地不同填料层净化污水效果研究

通过采集复合垂直流人工湿地(IVCW)和水平潜流人工湿地(HSCW)侧面不同高度的水样,初步研究了两种湿地填料的表层、中层、底层分别对污水中CODCr,TN,TP的净化效果.结果显示:①对CODCr的去除,两种人工湿地均未表现出显著差异.②两种湿地对TN的去除,主要取决于填料的中层和底层.③IVCW的填料表层除磷效果稳定,随环境因素变化,填料的中、底层TP去除率存在显著差异;HSCW中除磷主要在填料的底层,表层和中层填料容易出现明显的基质磷释放现象.     

环糊精水解酶cds1-3底物通道氨基酸的定点突变研究

本研究对具有大分子水解能力的环糊精水解酶cds1-3的蛋白结构进行分析,选取底物通道相关氨基酸进行定点突变。通过比较突变酶和野生酶的功能差异,定位决定cds1-3特殊功能的氨基酸。采用sybyl 1.2进行蛋白质底物结合分析,选取和多聚体形成、底物结合以及底物通道相关的氨基酸Glu66、Pro48、Phe289为突变位点,反向PCR构建pSE380/E66G、pSE380/P48H、pSE380/F289A表达质粒并进行表达,获得酶活突变体并与原始酶进行底物特异性比较分析。其结果显示,突变酶E66G降解大分子底物木薯淀粉和支链淀粉的相对酶活力分别提高26.96%和23.15%,而对小分子底物普鲁兰糖的水解能力下降13.14%。因此,cds1-3是一个能水解大分子底物的特殊环糊精水解酶,氨基酸Glu66是cds1-3水解大分子支链淀粉的关键氨基酸之一。     

氢化非晶碳膜导电机制的探索

采用电子回旋共振等离子体化学气相沉积 (ECR -CVD)方法 ,以苯为气源 ,在不同基片温度下制备了氢化非晶碳膜 (a -C :H) ,对样品进行了伏安特性测试。考察了基片温度对样品电阻率与击穿场强的影响 ,结合薄膜含氢量、SEM、Raman散射等分析手段探索了a -C :H膜的导电机制     

对医用椭圆环微带照射器基片厚度的研究

根据椭圆环微带照射器的频域理论,对工作在２４５０ＭＨｚ的医用椭圆环微带照射器进行近场分布的计算,分析基片厚度的变化对近场分布的影响,并找出了较满意的椭圆环结构参数,以适合地医学应用的要求。     

超平坦化Gd3Ga5O12(111)基片用于石榴石结构材料薄膜的生长

通过高温退火处理获得了具有在原子尺度范围内平坦化表面的Gd3Ga5O12(111)基片。在此基片上生长的Y3Fe5O12薄膜的表面光滑度有明显提高。与商品的Gd3Ga5O12(111)基片相比,超平坦化的Gd3Ga5O12(111)基片在生长石榴石结构材料薄膜方面具有明显的优越性。     

Substrate specificity of γ-secretase and other intramembrane proteases

γ-Secretase is a promiscuous protease that cleaves bitopic membrane proteins within the lipid bilayer. Elucidating both the mechanistic basis of γ-secretase proteolysis and the precise factors regulating substrate identification is important because modulation of this biochemical degradative process can have important consequences in a physiological and pathophysiological context. Here, we briefly review such information for all major classes of intramembranously cleaving proteases (I-CLiPs), with an emphasis on γ-secretase, an I-CLiP closely linked to the etiology of Alzheimer’s disease. A large body of emerging data allows us to survey the substrates of γ-secretase to ascertain the conformational features that predispose a peptide to cleavage by this enigmatic protease. Because substrate specificity in vivo is closely linked to the relative subcellular compartmentalization of γ-secretase and its substrates, we also survey the voluminous body of literature concerning the traffic of γ-secretase and its most prominent substrate, the amyloid precursor protein. Received 4 October 2007; received after revision 1 December 2007; accepted 7 December 2007     

Substrate specificity of bacterial DD-peptidases (penicillin-binding proteins)

The DD-peptidase enzymes (penicillin-binding proteins) catalyze the final transpeptidation reaction of bacterial cell wall (peptidoglycan) biosynthesis. Although there is now much structural information available about these enzymes, studies of their activity as enzymes lag. It is now established that representatives of two low-molecular-mass classes of DD-peptidases recognize elements of peptidoglycan structure and rapidly react with substrates and inhibitors incorporating these elements. No members of other DD-peptidase classes, including the high-molecular-mass enzymes, essential for bacterial growth, appear to interact strongly with any particular elements of peptidoglycan structure. Rational design of inhibitors for these enzymes is therefore challenging.     

凸球面基底超声波喷雾涂胶的研究

针对大尺寸曲面元件涂布光刻胶难的问题,提出一种超声波喷雾涂胶法用于解决这一难题。以凸球面基底为例,阐述了超声波喷雾涂胶装置在凸球面基底上涂布光刻胶的过程并且给出了光刻胶膜厚和主要操作参数之间关系的数学模型。然后根据该数学模型来控制喷涂参数,在口径为100 mm,曲率半径为120 mm的凸球面基底上进行光刻胶膜厚为5μm的涂布实验。从实验结果可以得出超声波喷雾涂胶法对大尺寸凸球面基底的光刻胶涂布具有一定的借鉴作用。     

硅和蓝宝石基底上的高Tc薄膜

使用多层沉积和大块沉积两种技术,在硅和蓝宝石的单晶基底上沉积了Yba2XCu3O7高Tc薄膜,实验显示：在硅基底上得到了转变温度为80K的期待结果．     

一种小型化基片集成波导滤波器的设计与实现

提出并设计了一种双重折叠四分之一模基片集成波导(double folded quarter mode substrate integrated waveguide,DFQMSIW)滤波器,滤波器通过在中间金属层开槽实现腔体间的耦合。相比于四分之一模基片集成波导滤波器,DFQMSIW滤波器的平面面积减小了约四分之三。理论、仿真和测试结果表明,该滤波器具有损耗小、易集成等优点,在设计小型化微波滤波器方面具有一定的参考价值。