杂交型DNA电化学生物传感器研究进展

杂交型DNA电化学生物传感器是一类利用核酸互补配对杂交原理检测和分析特定DNA序列的电化学生物传感器。由于其具有快速简便、选择性好、灵敏度高等优点,在临床医学、遗传工程、环境检测、食品安全监测和生物科学等领域有着重要的应用价值。简述了杂交型DNA电化学生物传感器的一般原理,对共价键结合法、自组装法、生物素-亲和索法、电聚合法以及吸附法等单链DNA的固定方法和DNA杂交信号的直接和间接电化学转换机制的近期研究进展进行了深入探讨,并对其在医疗检测和转基因植物检测等基因检测方面的最新应用和发展趋势进行了论述。     

Influence of zinc on electrochemical discharge activity of Mg-6%Al-5%Pb anode

Mg-6%Al-5%Pb (mass fraction) anodes with different contents of zinc were prepared by melting and casting. The electrochemical discharge behavior of these anodes in 3.5% NaCl solutions was investigated by galvanostatic test and electrochemical impedance spectroscopy (EIS). The microstructures and the corroded surfaces of these anodes were studied by scanning electron microscopy (SEM) and emission spectrum analysis (ESA). The phase structures and the corrosion products of the anodes were analyzed by X-ray diffraction (XRD). The results show that zinc promotes the grain refinement of Mg-6%Al-5%Pb anode and makes the average discharge potential of Mg-6%Al-5%Pb anode more negative during galvanostatic test. Mg-6%Al-5%Pb anode with the addition of 1% (mass fraction) zinc has the best electrochemical performance. The activation mechanism of zinc to Mg-6%Al-5%Pb anode is as follows: The hydrolyzation of dissolved Zn²⁺ ions reduces the pH value of the solution near the surface of the anode and accelerates the dissolution of Mg(OH)₂ film; The precipitated Zn(OH)₂ with similar structure as Mg(OH)₂ combines with Mg(OH)₂ film easily and makes it break down.     

偶氮染料在活性炭纤维电极上的伏安特性

为了进一步明确偶氮染料在活性炭纤维电极上的电化学行为,在一个以活性炭纤维为工作电极、铂为辅助电极的三电极体系中,考察了苋菜红在活性炭纤维电极上的伏安特性。实验结果表明：（1）ACF电极与Pt电极析氢与析氧电位相近,Pt电极作为供电电极的存在对苋菜红在ACF电极上的伏安特性无影响;（2）负极化时,ACF具有较大的充电电流;（3）苋菜红在-0．1～-08V点位区间内存在电还原与电吸附的可能性,在0．6-1．4V存在电氧化可能性。     

电化学方法脱除高岭土中铁、钛杂质的研究

除去高岭土中铁、钛等杂质，有利于它的广泛应用．对淮北地区高岭土进行电化学处理，并对处理前后的试样进行了SiO2，Al2O3，Fe2O3和TiO2含量的测定，发现在保持SiO2和Al2O3总量基本不变的前提下，Fe2O3，TiO2的脱除率分别达到60．0％和31．7％．同时配合透射电子显微镜、X-衍射和EDX能谱对样品进行分析．结果表明，电化学处理后的高岭土颗粒明显细化，铁、钛含量明显减少．     

混凝土中变形与光圆钢筋腐蚀速率试验研究

为了比较含氯离子的混凝土中变形钢筋及光圆钢筋腐蚀特征和腐蚀速度的不同，制作了同时含有变形和光圆2种钢筋并掺加了质量为水泥质量3％的盐ω（NaCl）的混凝土试件，然后进行了近一年的室外自然气候暴露试验．试验期间利用电化学线性极化法和试件腐蚀失重称量方法测试了2种钢筋的腐蚀速度；并分析和总结了它们的腐蚀特征．试验结果表明光圆钢筋的腐蚀机理主要是微电池腐蚀，腐蚀形态比较均匀，平均腐蚀失重率比变形钢筋大；而变形钢筋腐蚀机理主要是宏电池腐蚀，腐蚀主要发生在钢筋表面某几个局部区域，局部最大坑蚀深度约为光圆钢筋最大坑蚀深度的1．7倍．     

表面活性剂在酚类电化学测定中的应用及其机理探讨

报道了一种提高酚类检测灵敏度的简易方法.通过向溶液中添加表面活性剂十六烷基三甲基溴化胺、氯代十六烷基吡啶,可显著提高苯二酚、二硝基酚、萘酚及其异构体在玻碳电极上的电化学响应.探讨了表面活性剂的协同作用机理,研究了苯二酚、二硝基酚、萘酚测定的最佳pH值及表面活性剂添加量,研究成果对酚类及取代基酚类的检测和进一步研究具有重要意义.     

Evaluation of graded-channel SOI MOSFET operation at high temperatures

This paper presents a comparative analysis between graded-channel (GC) and conventional fully depleted SOI MOSFETs devices operating at high temperatures (up to 300 °C). The electrical characteristics such as threshold voltage and subthreshold slope were obtained experimentally and by two-dimensional numerical simulations. The results indicated that GC transistors present nearly the same behavior as the conventional SOI MOSFET devices with similar channel length. Experimental analysis of the g_m/I_DS ratio and Early voltage demonstrated that in GC devices the low-frequency open-loop gain is significantly improved in comparison to conventional SOI devices at room and at high-temperature due to the Early voltage increase. The multiplication factor and parasitic bipolar transistor gain obtained by two-dimensional numerical simulations allowed the analysis of the breakdown voltage, which was demonstrated to be improved in the GC as compared to conventional SOI transistors in thin silicon layer devices in the whole temperature range under analysis.     

Safety aspects of the combined HTTR/steam reforming complex for nuclear hyrogen production

The High-Temperature Engineering Test Reactor (HTTR) in Oarai, Japan, has the potential to demonstrate the production of hydrogen by steam reforming and using nuclear process heat as primary energy input. Particular safety aspects for such a combined nuclear/chemical complex have been investigated such as fire and explosion hazard at presence of flammable gases (LNG, H₂, CO) near the reactor building. A methane vapor cloud in the open atmosphere or partially obstructed areas is highly unlikely to detonate and damage the reactor building. Theoretical assessments and experimental studies significant to the HTTR-steam reforming system, include the spreading and combustion behavior of cryogens and flammable gases providing the basis for a comprehensive safety analysis of the nuclear/chemical facility.     

钛合金表面硬化与固体润滑处理层的电化学腐蚀行为研究

分别利用等离子氮化技术和离子束增强沉积(IBED)技术使钛合金表面获得硬质抗磨层和MoS2，MoS2-Ti固体润滑膜层。通过电化学测试技术研究了膜层和钛合金基材在含Cl^-介质中的抗蚀性能和接触腐蚀敏感性：研究结果表明：Ti与MoS2的复合改善了MoS2膜的环境适应性，MoS2—17Ti复合膜层与钛合会接触相容；IBED TiN较钛合金电化学活性低，阳极极化行为与Ti6Al4V合金相近，与钛合金基体间电偶腐蚀敏感性低；钛合金等离子氮化处理层在NaCl水溶液中无论处于自然腐蚀电位还上弱阳极极化状态，均较钛合金电化学活性低，且与钛合金基体间电偶腐蚀敏感性低。