胆甾醇疏水改性的羧乙基普鲁兰多糖合成及自组装性质

背景:将羧基引入疏水改性的多糖,使其自组装的纳米粒子带上表面电荷,有利于提高其稳定性,更好的发挥作为药物载体的优良性质。目的:观察合成胆甾醇疏水改性的羧乙基普鲁兰多糖在水溶液中的自组装行为及其纳米粒子的性质。方法:利用丙烯酸与普鲁兰多糖反应生成羧乙基普鲁兰多糖(CEP),然后按前期方法合成胆甾醇琥珀酰基N-羟基琥珀酰亚胺(CSN),最后CSN和CEP在催化剂下生成目标物。应用核磁共振仪对产物进行表征。结果与结论:通过1H-NMR分析,表明成功合成了胆甾醇疏水改性的羧乙基普鲁兰多糖,该材料在水溶液中能自组装为具有乳光的球型纳米粒子。CHS-CEP纳米粒子平均粒径为148.6nm,平均Zeta电位约为-19.9mV,在水溶液中分散度好,分布均匀,具有长期稳定性,可作为良好的药物载体

Application of single poise counterweight method in adjusting grinding uniformity of silicon wafer

为提高硅片研磨的均匀性,提出了一种通过改变调节砝码位置的新方法。对单砝码配重法的原理、步骤及物理模型进行了详细的论述,并基于lAbVIEW软件对该方法进行了可视化。在精密研磨抛光机上进行实验,并用膜厚仪进行均匀性测量。结果表明:在给定的条件下使9.9 CM硅片的均匀性从单靠自重研磨的20μM提高到用配重法调节后的3μM,显著提高了硅片研磨的均匀性。单砝码配重法为解决硅片研磨均匀性问题提供了一种既精确又简便的方法。To improve the grinding uniformity of silicon wafer,this paper proposed a new approach by changing the position of poise.The principle,procedure and physical model of the single poise counterweight method were described in detail,and then the visualization of this method basing on LabVIEW software was realized.Experiment was carried out on a precision grinding and polishing machine,and the thickness uniformity was measured on the thickness monitor.Experimental results show that the uniformity of three inches silicon wafer is improved from 20 μm to 3 μm comparing to conventional deadweight grinding,so the grinding uniformity of silicon wafer is enhanced markedly.Therefore,the single poise counterweight method provides a precise and convenient way to solve the grinding uniformity problem of silicon wafer.航空科学基金(20110868001

Luminescence of Strain Compensated Si/Si_(0.62)Ge_(0.38) Quantum Well Grown on Si_(0.75)Ge_(0.25) Virtual Substrate

由于SI/SIgE异质结构的带阶差主要发生在价带,为实现高效率的发光,本文从理论上设计了在硅基SI1-XgEX虚衬底上外延应变补偿的SI/S1-ygEy(y>X)量子阱的能带结构,将量子阱对电子的限制势垒提高到100MEV以上。在实验上,采用300℃生长的gE量子点插入层,制备出薄的SIgE驰豫缓冲层(虚衬底),表面gE组份达到0.25,表面粗糙度小于2nM,驰豫度接近100%。在我们制备的SIgE缓冲层上外延了应变补偿SIgE/SI多量子阱结构,并初步研究了其发光特性。In this paper,band structures of strain compensated Si/S_(1-y)Ge_y(y>x) quantum well grown on Si_(1-x)Ge_x virtual substrate was design to enlarge the conduction band offset up to 100meV for improving luminescence.The fully strain-relaxed Si_(0.75)Ge_(0.25) virtual substrate was prepared by inserting a low-temperature Ge islands layer in ultra-high vacuum chemical deposition.The root-mean-square surface roughness of the virtual substrate is less than 2nm.The luminescence of the strain compensated Si/SiGe quantum well on the virtual substrate was investigated.国家重点基础研究发展计划资助项目2007CB613400;国家自然科学基金资助项目(60676027;50672079

Study on Rhizodegradation of Soluble Protein by Sesuvium portulacastrum Linn.

采用水培法研究了海马齿(SESuVIuM POrTulACASTruM lInn.)与其根际微生物对可溶性蛋白质的联合降解作用.分别设置抑菌和不抑菌的植物组、细菌组和对照组并连续添加蛋白质,测定了降解过程中蛋白质的浓度、细菌密度和亮氨酸氨基肽酶活性的变化.结果显示,在不抑菌实验中,植物组的蛋白质浓度下降最快.36H后,植物组、细菌组和对照组的降解率分别是97%、41%和26%.蛋白质的降解过程伴随着细菌数量的增加和亮氨酸氨基肽酶活性的升高,植物组的亮氨酸氨基肽酶活性始终高于细菌组.24H后,植物组的亮氨酸氨基肽酶活性达到最高值0.75μMOl/(l·H),此后酶活性下降至0.22μMOl/(l·H).细菌组的亮氨酸氨基肽酶活性最高值出现在60H,达到0.43μMOl/(l·H),至结束时降低为0.说明海马齿与根际细菌联合作用下,胞外酶活性升高,蛋白质降解效率最快.在抑菌实验中,抗生素有效抑制了细菌的生长,3个处理组的蛋白质变化趋势基本一致,实验过程中检测不到亮氨酸氨基肽酶,说明单纯的海马齿根系不分泌该胞外酶.研究表明,在蛋白质的根际降解过程中,根际细菌是亮氨酸氨基肽酶的分泌者和蛋白质降解的主要执行者,但根际细菌对蛋白质的高效降解必须以海马齿根系为依托.本研究结果为更好地利用海马齿生态浮床修复海水环境中的有机氮提供了理论依据.Phytoremediation of soluble protein by marine halophyte Sesuvium portulacastrum which has been supposed to use in ecofloating bed systems was studied through a hydroponic culture approach.The plant group,the bacteria group and the control group were treated with and without antibiotic addition.The results showed that,without antibiotic addition,each time after bovine serum albumin(BSA)was added,the BSA concentration of the plant group dropped fastest.After 36hincubation,the degradation rate of the plant group,the bacteria group and the control group was 97%,41%and 26%respectively,i.e.the degradation rate of the plant group was significantly higher than the bacteria group.Protein degradation associated with the increasing of both leucine amino peptidase activity(LAPA)and bacterial density,and LAPA of the plant group was always higher than that of the bacteria group.Soon after the experiment started,LAPA of the plant group increased rapidly and reached its maximum value of 0.75μmol/(L·h)at 24h.Then LAPA started to decline to 0.22μmol/(L·h)till the experiment ended.The maximum LAPA value of the bacteria group was 0.43μmol/(L·h)at 60h,and till the experiment ended,the LAPA was 0μmol/(L·h).With antibiotic addition,the bacterial density of both plant group and bacteria group showed downtrend,and it showed that the antibiotic inhibited the growth of bacteria effectively.The degradation rates of 3groups were almost the same,and LAPA was not detected in the procession.It was suggested that in the procession of rhizodegradation of BSA by S.portulacastrum,the extracellular enzyme was produced by rhizosphere bacteria,and the rhizoshpere microbe was the main performer of BSA degradation.Besides,the high degradation rates of rhizosphere bacteria relied on the root of S.portulacastrum.The results provide meaningful insights into the interrelationship between microbes and plant as well as the practical significance of soluble protein rhizodegradation in seawater environments by eco-floating bed system.国家海洋公益性行业科研专项(201205009); 深圳市科技研发资金(JCYJ20120830153030587

n-ZnO/p-AlGaN LED结构DFB激光器的设计与分析

根据严格耦合波理论和介质平板波导理论,利用Comsol Multiphysic软件仿真设计了基于单晶n-ZnO/p-AlGaN LED（发光二极管）结构的DFB（分布反馈）半导体激光器的光栅结构。针对LED结构加电压后发射近紫外光,分析了二维电场模式分布图,得出单纵模传输随着光栅不同参量的变化情况。分析表明,在4 V正向偏置电压下,当占空比为50%、光栅周期为109.2 nm、光栅高度为69.8 nm时,光谱线宽窄、单模选择性好,电场模达5.877 4×107V/m。为电泵浦DFB半导体激光器的设计与加工提供了一定的基础