Low Density Self-Assembled InAs/GaAs Quantum Dots Grown by Metal Organic Chemical Vapour Deposition

The self-assembled InAs quantum dots （QDs） on GaAs substrates with low density （5×10^8 cm^-2） are achieved using relatively higher growth temperature and low InAs coverage by low-pressure metal-organic chemical vapour deposition. The macro-PL spectra exhibit three emission peaks at 1361, 1280 and 1204nm, corresponding to the ground level （GS）, the first excited state （ES1） and the second excited state （ES2） of the QDs, respectively, which are obtained when the GaAs capping layer is grown using triethylgallium and tertiallybutylarsine. As a result of micro-PL, only a few peaks from individual dots have been observed. The exciton-biexciton behaviour was clearly observed at low temperature.     

吖啶橙共振光散射法测定脱氧核糖核酸

研究了吖啶橙与DNA作用的共振散射光谱,发现在pH 11的碱性溶液中痕量核酸对吖啶橙的共振散射光产生增强作用,且增强程度与核酸浓度之间有良好的线性关系。据此建立了测定核酸的高灵敏共振光增强分析方法。其最大散射波长均位于324 nm处,测定鱼精DNA(fs DNA)的线性范围是3.1×10-8～7.3×10-6 g·mL-1,检测限20.5 ng·mL-1,测定小牛胸腺DNA(ct DNA)的线性范围是7.5×10-8～9.8×10-6 g·mL-1,检测限20.8 ng·mL-1。该方法简单,操作方便,选择性好,灵敏度高,用于合成样品的测定结果满意。     

骨科植入物的微动摩擦学研究现状及进展

骨科植入物在人体中的微动会引起植入物的磨损导致损伤,造成骨科手术的失败.本文介绍了植入物微动摩擦学的类型、研究方法、磨损机理及改善措施,详细阐述了当前国内外关于骨科植入物微动摩擦学的试验及数值模拟研究成果.建立1套可准确获得界面微动真实分布的科学方法,将有助于深入研究人体中界面微动,而将骨组织的生长模型与力学特性相结合,建立适于描述人体中植入物-骨组织的界面微动模型,对临床治疗及骨科植入物的优化设计具有非常重要的意义.     

偶氮喹啉-镍离子配合物应用于HSO-4识别研究

考察了5-(4'-氰基苯)偶氮-8-羟基喹啉(1)-镍配合物的光谱特性并将其应用于阴离子识别研究中.研究结果表明,1-Ni2+金属配合物可选择性识别不同的阴离子,并对HSO-4具有独特的光谱响应.化合物1在乙腈中为无色溶液,与Ni2+可形成稳定常数为9.2×10 6mol-1·L的1∶1型红色配合物,在此配合物中加入HSO-4后,红色的溶液逐渐褪色,而加入CH3CO-2,F-和H2PO-4却产生增色效应,Cl-和Br-加入后主体溶液无明显颜色和光谱变化,据此建立了选择性识别HSO-4新体系,并探讨其作用机理.     

石墨消解-ICP-MS法同时测定铜精矿中4种有害元素

为弥补标准检测方法的不足,建立了石墨消解-ICP-MS法同时检测铜精矿中Pb、Cd、As 和Hg等4种有害元素。确定了样品前处理和仪器分析条件。用铜精矿标准样品和参考样品分别进行7次重复实验,Pb、Cd和As的检测结果均在标准值范围内,Hg的检测结果与参考值基本一致。7次重复检测结果的变异系数符合GB/T 27417-2017《合格评定 化学分析方法确认和验证指南》要求。选择5种不同物相铜精矿作为待测样品,通过与标准方法比对,两种方法检测结果的绝对差符合标准方法的再现性要求,说明本方法适用于不同种类的铜精矿。本方法操作简单,可同时测定多种有害元素,实用性强。     

地黄提取物改善贫血大鼠记忆及其机制

地黄滋阴补血填髓,广泛用于贫血和脑疾病患者,但其功效机制尚未阐明.本文探讨地黄水提物(Rehmannia glutinosa’s water extracts,RGWE)改善血虚大鼠记忆及其滋阴补血填髓的可能机制.采用断尾放血结合注射环磷酰胺制备贫血大鼠模型,随机分溶媒组和地黄水提物3,6,10g/kg治疗组,灌服等体积自来水或不同剂量地黄水提物10天,采用Morris水迷宫观测大鼠空间记忆能力,采用酶联免疫吸附测定方法(Enzyme linked immunosorbent assay,ELISA)检测血浆红细胞生成素(EPO)水平,免疫组化和免疫蛋白印迹技术(Western blotting)检测分析脑EPO及其受体表达水平.成功制备血虚模型,表现为大鼠红细胞数和血红蛋白显著下降,与造模前比较差异显著(P<0.05),溶媒组空间记忆能力显著下降,地黄治疗组空间记忆能力明显提高,逃避潜伏期明显缩短(P<0.05),一定时间内穿越平台次数显著增多(P<0.05);免疫组化和Western blotting结果显示脑组织EPO及其受体表达、血浆EPO水平均较溶媒组明显升高(P<0.05).地黄水提物显著提高贫血...     

Prediction of Decomposition Temperature for Lanthanide Complexes Involving Cyclopentadienyl and Benzohydroxamic Acid Ligand by ANNs

The decomposition temperatures of the lanthanide organic complexes(η^5-C5H5)2Ln(C6H5CONHO)involving cyclopentadienyl and benzohydroxamic acid ligands were calculated and predicted by the model based on ANNs(artificial neural netowrks)method.The comparison was carried out between results from ANNs method and traditinal regression method.It is proved that ANNs could be used more efficiently for the prediction of decomposition temperature of lanthanide organic complexes.     

Synthesis of Cationic PEM Emulsion and Application in Waste Water Treatment

Cationic polymer as a kind of flocculant is widely applied in purification treatment of waste water. Because it has positive charge group, it is able to connect strongly the suspended matters, short cellulose and other microparticles. The research on synthesis of cationic polymer and application in treatment of waste water is very universal abroad. But domestic research on those is not general. The technology of synthesis of PEM is simple, and the production cost is low. It is easy to apply in treatment of waste water.Synthesis of PEM Emulsion FlocculantSome distilled water, PVA(poly(vinyl alcohol)), EA(ethyl acrylate), and K2S2O8(potassium persulfate) were put into reaction vessel. Kept stirring up under nitrogen. When heated the solution to 40℃, dropped the water solution of MTA[(2-methacryloxylethyl)trimethyl ammonium].Maintained the temperature at 70℃, reacted about 7-8 hours. Then got the PEM emulsion. Changed the ratio of EA and MTA. Obtained a series of PEM emulsions.Stability and Convertibility of PEM EmulsionThe test results showed that when the EA/MTA was 85/15, the PEM emulsion was most stable.When the total monomer quantity was 35%, the convertibility of PEM emulsion was the highest,i.e.98.6%.The MTA Copolymerization Ratio and Morphology of PEM EmulsionWhen the monomers EA/MTA=85/15 and total monomer quantity was 35%, the MTA copolymerization ratio of PEM emulsion was 95.15%(the highest), and the PEM emulsion was some microspheres with 100-180nm of diameter.The Test Results of PEM Emulsion in Treatment of Waste Water The PEM emulsion flocculant was applied in treatment of waste water of paper mill, and measured the precipitation time(t) and transmittancy(T). The test results were showed in table 1. The optimum value of PEM which was able to make the waste water of paper mill into clear water was 0.008%.     

牛血清白蛋白与十二烷基硫酸钠作用的机理

利用电动势法得到了牛血清白蛋白(BSA)与十二烷基硫酸钠(SDS)相互作用的结合等温线. 通过四阶导数紫外光谱法和荧光光谱法研究了相互作用过程中芳香族氨基酸残基微环境极性的变化. 通过研究发现, 随着SDS浓度的逐渐增大, SDS在BSA上的平均结合数(v)逐渐增大, 色氨酸(Trp)残基所处微环境的极性在减弱后保持基本不变, 酪氨酸残基所处微环境的极性在明显增强后稍有减弱, 苯丙氨酸残基所处微环境的极性略有增强. 结果表明, 当v由0增大到14时, SDS主要结合在BSA的Trp-213附近并逐渐形成聚集体, 从而诱导BSA由结构域ⅡA 开始逐渐展开. 此后, SDS呈正协同作用的特点与BSA 结合, v急剧增大. 当v约为302 时, SDS在BSA上的结合基本达到饱和, BSA的构象趋于稳定.     

高效液相色谱同时测定饲料中三种抗生素

建立了反相高效液相色谱法同时检测饲料中土霉素、四环素、金霉素的方法.色谱柱为AichromBond-AQ C18柱,150×4.6mm,粒度5μm;流动相:0.01mol/L磷酸二氢钠溶液(pH2.5)+乙氰,采用梯度洗脱,乙氰浓度在0～13min内由13%上升到40%;柱温35℃;流速为1.0mL/min;进样量101μL;检测波长375nm.方法检出限:土霉素和四环素0.25μg/mL、金霉素0.50μg/mL,回收率91.70%～101.19%,RSD<1.39%(n=7).