免标记DNA电化学传感器测定凝血酶

研制了一种基于介孔二氧化硅负载纳米金和适体DNA的免标记电化学传感器,用于检测凝血酶的含量。实验中先用三甲基氯硅烷(TMCS)封闭介孔二氧化硅(MPS)前驱体外壁硅羟基的活性,煅烧除去模板剂后,再用氨基丙基三乙氧基硅烷(APTS)与孔道内壁硅羟基反应,接枝氨基,最后得到内壁修饰氨基的介孔硅材料(APTS-TMCS-MPS)。金纳米粒子(GNPs)通过与APTS-TMCS-MPS氨基的静电作用力组装到介孔孔道内,然后和巯基修饰的适体DNA通过金硫键相结合,制得免标记探针(DNA/GNPs/APTSTMCS-MPS)。将探针修饰在玻碳电极表面,制得免标记DNA电化学传感器。将该传感器与含有凝血酶的待测液温育反应后,凝血酶和固定在介孔内的适体DNA发生特异性反应,形成位阻较大的适体DNA和凝血酶的复合物,从而增加了介孔孔道内的空间位阻,导致电流响应信号降低。随着凝血酶浓度的增加,孔道内部的位阻也随之增加。根据形成的复合物对电子转移和响应电流的阻碍,可以实现对凝血酶的免标记测定。实验结果表明,APTS-TMCS-MPS介孔孔道内的GNPs,可以提高孔道内电子的传递效率。在优化的实验条件下,该免标记DNA电化学传感器对凝血酶的检测线性范围是1.0×10-8~1.0×10-6 mol·L-1,检测限是7.5×10-9 mol·L-1(3σ)。     

复合正极材料xLiFePO_4·yLi_3V_2(PO_4)_3/C的合成及其电化学性能

以聚吡咯(PVP K60)为表面活性剂和碳源,采用流变相法合成了x Li Fe PO4·y Li3V2(PO4)3/C正极材料样品。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)对样品形貌和结构进行了测试;采用电池测试仪和电化学工作站对样品电化学性能进行了测试,分析了不同复合比(x:y)对其结构和电化学性能的影响。研究表明:复合材料中存在两相复合与元素掺杂两种效应;当复合比为5∶1时材料的电化学性能最优,在0.1和10 C倍率下放电容量分别达到162.7和104.6 m Ah·g-1,且具有良好的循环稳定性。     

Effects of Al and Sn on electrochemical properties of Mg-6%Al-1%Sn （mass fraction） magnesium alloy as anode in 3.5%NaCl solution

Mg-6%Al-1%Sn（mass fraction） alloy is a newly developed anode material for seawater activated batteries. The electrochemical properties of Mg-1%Sn, Mg-6%Al and Mg-6%Al-1%Sn alloys are measured by galvanostatic and potentiodynamic tests. Scanning electron microscopy（SEM） with energy dispersive spectrometry（EDS） is used to characterize the microstructures of the experimental alloys. The results show that the Mg-6%Al-1%Sn alloy obtains more negative discharge potential（-1.38 V（vs SCE）） in hot-rolled condition. This is attributed to the fine dynamically recrystallized grains during the hot rolling process. After the experimental alloys are annealed at 473 K for 1 h, the discharge potentials of Mg-6%Al-1%Sn alloy are more negative than those of Mg-6%Al alloy under different current densities. After annealing at 673 K, the discharge potentials of Mg-6%Al-1%Sn alloy become more positive than those of Mg-6%Al alloy. Such phenomenon is due to the coarse grains and the second phase Mg2 Sn. The discharge potentials of Mg-1%Sn shift positively obviously in the discharge process compared with Mg-6%Al-1%Sn alloy. This is due to the corrosion products pasting on the discharge surface, which leads to anode polarization.     

NH_4Cl薄层液膜下X70钢腐蚀的电化学研究

采用电化学阻抗法和阴极极化曲线法研究了X70钢在含NH4Cl薄层液膜下的电化学行为.研究了液膜厚度、NH4Cl浓度对X70钢腐蚀行为的影响.结果表明,液膜厚度降低,X70钢腐蚀电位正移,阴极极限扩散电流增大.液膜厚度为130μm时,阴极极限扩散电流达最大值.液膜厚度为130~100μm时,阴极极限扩散电流反而降低.液膜厚度进一步减薄,阴极极限扩散电流又增大.薄层液膜下,NH4Cl浓度增大,阴极极限扩散电流减小,抑制了阴极过程;随着NH4Cl浓度增大,X70钢腐蚀的电荷传递电阻减小,对阳极过程有一定的促进作用,从而加速X70钢的腐蚀速率.     

AZ91D镁合金表面环保型钙系磷化膜的制备及其耐蚀性

采用化学转化处理的方法,在AZ91D镁合金的表面制备了均匀致密的钙系磷化膜,其中磷化液配方中不含铬、氟及亚硝酸盐等对环境有害的离子。通过场发射扫描电子显微镜和X射线衍射仪研究了磷化时间及温度对磷化膜结构和相组成的影响。结果表明:磷化时间为20min,磷化温度为40℃时,所得到的磷化膜的致密性和均匀性较好。与空白基体相比,经磷化处理后的镁合金在3.5%NaCl溶液中的耐腐蚀性能明显提高。     

5Cr套管钢在不同CO2分压下高温高压腐蚀特性研究

为了研究5Cr套管钢在不同CO₂分压下的腐蚀特性,进行了5Cr套管钢高温高压腐蚀失重和高温高压电化学试验,并采用XRD、SEM和EDS等手段对其腐蚀产物进行微观分析。结果表明,在高温高压腐蚀环境下随着CO₂分压从低到高,其表面点蚀坑的深度和直径均无明显变化,而点蚀速率则出现逐渐减小的趋势;其腐蚀产物膜由Cr(OH)₃、FeCO₃和CaCO₃共同组成,且随着CO₂分压的升高Cr的富集量逐渐增加;在电化学测试中,随着CO₂分压的不断升高,5Cr套管钢表现出半钝化特征,产物膜逐渐增厚且致密,且极化电阻逐渐增大,阳极反应受到抑制,电化学反应阻力增大,其抗局部腐蚀能力不断提高。     

TiO2-SnO2 coated bamboo biochar for electrochemical treatment of coking wastewater

A new type of bamboo biochar (BC) loaded TiO₂-SnO₂ particle electrode was prepared and characterized by SEM, FT-IR, BET and XRD for efficient treatment of the coking wastewater in a three-dimensional electrochemical reaction system(3DERs). The results showed that bamboo biochar had a dense microporous space structure, and a significant amount of Ti-Sn oxides existed on the surface and in the interior of the BC. The removal rates of COD and DOC in coking wastewater reached to 73.96% and 66.72% respectively, and UV₂₅₄ reduced from 6.65 cm^-1 to 3.00 cm^-1 by the electrolysis treatment of 150 min at the current density of 30 mA/cm². The three-dimensional fluorescence spectra indicated that the most of the soluble organic compounds and soluble microbial by-products were degraded and transformed. The addition of Ti and Sn enhanced the efficacy of the electrooxidation, electro-adsorption and electrocatalytic behavior of the BC particle electrodes, which improved the treatment effect on coking wastewater in the 3DERs. In addition, this study provides the possibility of basic research for the engineering practice of electrochemical oxidation treatment of coking wastewater.     

Analysis of corrosion behavior of LY12 in sodium chloride solution with wavelet transform technique

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Characteristics of graphite felt electrode electrochemically oxidized for vanadium redox battery application

The graphite felt was oxidized at a positive electrode potential in sulfuric acid solution.The electrochemical performance of the treated graphite felt served as electrode for vanadium redox battery was investigated with FT-IR,SEM,XPS,BET,cyclic voltammetry and testing VRB system,respectively.The results show that the molar ratio of O to C increases from 0.085 to 0.15 due to the increase of—COOH functional groups during electrochemical oxidation treatment,and the GF surface is eroded by electrochemical oxidation,resulting in the surface area increase from 0.33 m2/g to 0.49 m 2/g.The VRB with modified GF electrode exhibits excellent performance under a current density of 30 mA/cm 2 .The average current efficiency reaches 94%and average voltage efficiency reaches 85%.The improvement of electrochemical activity for the electrode is ascribed to the increase of the number of—COOH group and the special surface of GF.     

镍硫化物阳极溶解的电化学研究

研究了合成镍硫化物的阳极过程。Ni_3S_2,Ni_7S_6和NiS的活性溶解伴随着生成表面产物层,其反应机理与电极电位有关。根据三种不同类型产物层生成规律的电化学研究,Ni溶出表观电子数的测定,以及产物层相组成分析和相的元素分析,认为存在三组平行反应:直接生成HSO_4~-或SO_(4-)~2的反应,生成中间硫化物的反应及生成元素硫的反应,每组反应具有不同的优势发展电位区。NiS_2阳极溶解时,基本上为生成HSO_(4-)或SO_(4-)~2的反应。