基于钯(Ⅱ)-8-羟基喹啉-5-磺酸-十二烷基硫酸钠络合体系极谱法测定SOD活性

在Na2CO3-NaHCO3(pH8.9)缓冲溶液中,十二烷基硫酸钠(SDS)对钯(Ⅱ)与8-羟基喹啉-5-磺酸(8-OXSA)络合物峰电流有明显的增敏作用,其电极反应机理是电极表面生面的O2-催化氧化反应中间体所致。由于超氧化歧化酶(SOD)可催化O2-发生歧化反应,使钯-8-OXSA-SDS体系的峰电流降低,可通过测定峰电流的变化可以间接定量SOD的活性,据此建立测定SOD活性的方法,并研究几种常见的黄酮类化合物清除O2-的作用。     

DN-2型钠离子浓度计电极国产化的研制

微机化在线钠离子浓度计的关键问题即为电极国产化问题。详细介绍了电极国产化的研制过程，从研究钠电极的特性入手，分析了进口钠电极和国产钠电极的工作原理及特性异同点。结合DN-2型钠离子浓度计的实际电路，对原电路进行了适当的改造。通过采用电极转换电路，使国产电极能够应用于DN-2型钠离子浓度计，实现了电极国产化，取得了较好的使用效果及较高的经济效益。     

新型共平面微气体传感器微热板的优化设计

利用金属铂良好的热敏、热阻特性,以及Si O2良好的绝热、绝缘性能,设计了以铂为加热电极、以Si O2为绝缘材料的新型共平面微结构气体传感器。为了使该传感器获得高且均匀的温度分布,利用有限元软件ANSYS对该传感器的电极和基底进行仿真分析,并进一步优化该传感器的基底以及电极参数。仿真结果表明:传感器基底形状设计为方形结构,基底的前Si O2层、中间Si层、后Si O2层的厚度依次为1、199、100μm,且加热电极的宽度及间距均为20μm、信号电极宽度为40μm时,传感器上获得了最佳的温度分布,此时的磁场分布也较好,有利于传感器整体性能的提高。     

铝合金点焊过程的铜铝合金化研究

观测了LF2铝合金电阻点焊初期至达到电极寿命时焊点表面及Cr—Zr—Cu电极端面宏观形貌的连续变化过程。采用扫描电子显微镜(SEM)，对机加工状态及抛光处理的电极在点焊铝合金后进行了电极端面背散射分析，对机加工状态的电极在点焊铝合金后又进行了电极端面横向及纵向线扫描分析。采用X射线衍射仪，对沿电极轴向的3个不同电极端面进行了X射线衍射物相分析。结果表明，点焊初期，焊点表面即出现局部熔化及电极端面出现明显凹凸不平，电极端面的形貌及其尺寸发生变化，焊点表面成形质量恶化，电极端面加工状态对电极端面铜铝合金化影响不大，点焊过程电极端面存在较多铝，发生了铜铝合金化反应，合金化产物主要是铜铝金属间化合物(CuAl2)。     

应用草酸电解配制动态微量CO-2标准气体的方法

一、电解配气原理:草酸在水溶液中解离为草酸根阴离子和氢离子H2C2O4AH C2O4草酸水溶液在电解时在电极上的反应: 阳极上:C20     

RuO_2·nH_2O对质子交换膜燃料电池动态响应的影响

为了改善质子交换膜燃料电池在作为移动动力源时的动态响应,提出一种在质子交换膜燃料电池中引入RuO2·nH2O的方法,使质子交换膜燃料电池具备了超级电容器功能.首先以溶胶-凝胶法合成了RuO2·nH2O水溶胶,以提拉法将Nafion膜表面附上一层RuO2·nH2O;将此膜制成膜电极,通过对电极的循环伏安测试和对电池的稳态性能测试的结果证明了RuO2·nH2O的加入没有影响Pt的活性,对电池的稳态性能没有负面影响;通过对电极作多电位电势阶跃计时电流测试和脉冲电流下的电压响应测试,结果显示了RuO2·nH2O作为电容材料加入到质子交换膜燃料电池的膜电极中,在电池瞬间加载时可以缓冲电池电压大幅度衰减的现象,起到了改善电池动态响应的作用.     

TEM剖析合成过程中影响纳米Y2O3形貌的因素

通过透射电子显微镜（TEM）对纳米Y2O3合成过程进行观察，经过对TEM照片中Y2O3拉度和形貌分析，找出在合成反应过程中对纳米Y2O3粒度和形貌变化的重要影响因素。并通过对合成反应影响因素控制，设计制备理想拉度和形貌的纳米Y2O3。研究结果表明：沉淀剂种类、表面活性剂浓度、合成反应温度是影响纳米Y2O3拉度和形貌的主要因素。     

掺硼金刚石厚膜电极污水处理实验研究

在EACVD(electron-assisted hot filament chemical vapor deposition)金刚石膜沉积系统上制备出了掺硼金刚石厚膜电极,采用循环伏安法研究了掺硼金刚石厚膜电极和IrO2/Ta2O5钛涂层电极电化学性能的差别,结果表明掺硼金刚石厚膜电极具有比IrO2/Ta2O5钛涂层电极更宽的电势窗口(约3.4V)和更低的背景电流(接近于零).用所制备的掺硼金刚石厚膜电极和IrO2/Ta2O5钛涂层电极对比处理高浓度难降解污水,通过测定污水处理过程中化学需氧量(chemical oxygen demand,COD)的变化、观察污水处理过程中颜色的变化、处理前后两电极的SEM照片研究了掺硼金刚石厚膜电极在污水处理中的应用,试验表明掺硼金刚石厚膜电极比IrO2/Ta2O5钛涂层电极处理污水效率更高、处理高浓度难降解污染物的能力更强,电极更加稳定、耐腐蚀性更好,是一种很有应用前景的电极.     

工业纯Fe_2O_3及处理对合成SHS煤粉喷枪内衬陶瓷的影响

通过重力分离 SHS法制备陶瓷内衬煤粉喷枪 ,研究了 Fe2 O3粉末性能 (纯度、粒度和表面状态 )对合成 SHS煤粉喷枪内衬陶瓷的影响。结果表明 ,在铝热剂中相同质量百分数条件下 ,工业纯 Fe2 O3粉末中的杂质比 Si O2 添加剂对燃烧过程中的稀释效应更为强烈 ;降低 Fe2 O3粒度虽使蔓延速率下降 ,但却使燃烧温度和 SHS反应转化率提高 ;对工业纯 Fe2 O3粉末进行 1 50°C烘干处理 ,燃烧温度、蔓延速率与反应转化率随烘干时间增加而增大。     

基于纳米氧化镧的精密电铸工艺试验研究

采用纳米稀土La2O3为添加剂，研究其对电铸镍溶液特性、铸层微观结构及其性能的影响。通过对沉积过程中阴极极化曲线的测定，探讨了纳米La2O3在电极表面的作用机理，并采用SEM、XRD等现代分析手段对电铸层微观结构进行了测试和分析。试验结果表明：纳米La2O3能够在阴极表面发生特性吸附，增大阴极极化，细化精密电铸层晶粒，提高铸层的均匀性；晶粒生长在（220）晶面方向上存在明显的择优取向；获得的电铸层显微硬度比普通电铸层有显著提高。     

金属电极材料对YSZ氧传感器性能的影响

借助循环伏安和计时电流方法,研究了金属电极材料对YSZ氧传感器性能的影响。结果表明,在500℃和空气条件下,Ag-1%Pd/YSZ电极由于具有合适的微观结构以及较强的氧扩散能力,使其无论是作为YSZ氧传感器的阳极还是阴极,性能均为最好,而Au/YSZ电极最差;各金属/YSZ电极具有相似的阳极极化计时电流曲线,其电流密度值在10 s之内即可达到平稳;随着阳极阶跃极化电位增大,使得参加电极还原反应的氧原子数量增加,从而导致Ag-1%Pd/YSZ电极电流密度稳定值亦增大。     

Experimental research on machining characteristics of SiC ceramic with end electric discharge milling

Silicon carbide (SiC) ceramic has been widely used in modern industry. However, the beneficial properties of SiC ceramic make machining difficult and costly by conventional machining methods. This paper proposes a new process of machining SiC ceramic using end electric discharge (ED) milling. The process is able to effectively machine a large surface area on SiC ceramic at low cost and no environmental pollution. The effects of emulsion concentration, emulsion flux, milling depth, copper electrode number, and copper electrode diameter on the process performance such as the material removal rate, electrode wear ratio, and surface roughness have been investigated. In addition, the microstructure of the machined surface is examined with a scanning electron microscope, and the material removal mechanism of SiC ceramic during end ED milling is obtained.     

Gas Pool Coupled Activating TIG Welding Method with Coupling Arc Electrode

Gas pool coupled activating TIG(GPCA?TIG) welding put forward in?house can dramatically enhance weld penetration of TIG welding through introducing active element oxygen to reverse the Marangoni convection flow in the molten pool. In order to further improve the welding productivity, the normal solid tungsten electrode is replaced by a kind of coupling arc electrode. The changes of arc pressure distribution along anode surface and the weld appearance were evaluated. On this basis, the dependences of weld shape characterized with weld depth, width and undercut on the main welding parameters were discussed. The results indicate, the substitution of coupling arc electrode can lead to an obvious decrease of arc pressure. Compared to hollow tungsten electrode and twin tungsten electrodes, the coupling arc electrode is much easier to manufacture and has more compacter structure. Combined with the symmetric distribution of arc pressure in di erent directions, this electrode has extensive adaptability. In the GPCA?TIG welding with coupling arc electrode, both the substitution of coupling arc electrode and the introduction of outer active gas oxygen can reduce the possibilities of producing humping bead and undercut. Their joint action makes this welding method have the capability of realizing high travel speed and deep penetration welding.     

Accretion of titanium carbide by electrical discharge machining with powder suspended in working fluid

A surface modification method by electrical discharge machining (EDM) with a green compact electrode has been studied to make thick TiC or WC layer. Titanium alloy powder or tungsten powder is supplied from the green compact electrode and adheres on a workpiece by the heat caused by discharge. To avoid the production process of the green compact electrode, a surface modification method by EDM with powder suspended in working fluid is proposed in this paper. After considering flow of working fluid in EDM process, the use of a thin electrode and a rotating disk electrode are expected to keep powder concentration high in the gap between a workpiece and an electrode and to accrete powder material on the workpiece. The accretion machining is tried under various electrical conditions. Titanium powder is suspended in working oil like kerosene. TiC layer grows a thickness of 150 μm with a hardness of 1600 Hv on carbon steel with an electrode of 1 mm in diameter. When a disk placed near a plate rotates in viscous fluid, the disk drags the fluid into the gap between the disk and the plate. Therefore, the powder concentration in the gap between a workpiece and a rotational disk electrode can be kept high. A wider area of the accretion can be obtained by using the rotational electrode with a gear shape.     

ZrO2氧传感器多孔铂电极热处理工艺

多孔铂电极作为ZrO2氧传感器的重要组成部分,主要起催化、导电作用,对氧传感器的氧敏性能影响较大.通过对多孔铂电极进行不同形式的高温热处理,发现适当热处理后电极电导率发生变化,电极多孔性能得到明显改善,响应性能得到很大程度提升.讨论了高温处理后电极各种性能改善的原因.     

Study of high-efficiency electrical discharge machining-induced ablation machining of titanium alloy TC4 using a multi-function electrode

Aimed at overcoming the low efficiency of electrical discharge machining (EDM), and taking advantage of the characteristic that most metals can burn in oxygen, a new high-efficiency process is put forward: EDM-induced ablation machining (EDM-IAM) using multi-function electrode technology. EDM-IAM injects oxygen and dielectric fluid into the processing area through a dedicated channel of a multi-function electrode. The chemical energy caused by the reaction of metal and oxygen can much improve the material removal efficiency. To study the factors affecting the efficiency of the process, the ablation machining of a titanium alloy (TC4) using a multi-function electrode was carried out; analysis of the worked surface was done with scanning electron microscopy, X-ray diffraction, and discharge waveforms. The results show that the substances of the worked surface are mainly TiO, TiO_1.2, TiO₂, and smaller amounts of Ti₃O and other titanium oxides. Violent oxidation combustion reaction occurs during the ablation machining process. The processing efficiency of ablation machining can reach 347.7 mm³/min, which is 58.7 times that of normal EDM for the same processing conditions. The main reasons for the high material removal rate are the higher utilization rate of electric spark discharge energy, consumption of material by ablation, melting effect of combustion heat on the workpiece material, and forced chip removal effect by local explosion.     

电势型固体电解质氧传感器电极制备及响应性能

研究了电极涂覆面积、电极涂覆位置和电极催化剂用量对电势型固体电解质氧传感器响应特性的影响.结果表明:电极涂覆面积和电极涂覆位置的变化会导致传感器电极极化电阻和电解质电阻的变化,但对传感器的响应特性却几乎没有影响;一定范围内电极催化剂载量的增加有助于减小电极表面电阻、电极极化电阻以及传感器的电解质电阻,但同时也会增加电极中气体的传质阻力.因此制作电极时,催化剂的载量需要优化.一般以传感器电极表面电阻刚好小于1Ω时的载量为最佳电极催化剂载量.     

Immobilization of iron storage protein on a gold electrode based on self-assembled monolayers

Ferritin is a globular protein consisting of 24 subunits to form a hollow shell and is capable of storing iron in the cavity. Findings that the naturally existing iron core of ferritin can be readily extracted and replaced with a variety of electroactive materials make ferritin suitable for biosensor and biofuel cell applications. The immobilization of ferritin on the electrode surface is essential for various bioelectronic applications. In this work, based on self-assembled monolayers, ferritin was immobilized on a gold electrode through two different methods: chemisorption of thiolated ferritin onto bare gold electrodes and covalent binding of ferritin to succinimidyl alkanedisulfide-modified Au electrodes. Effects of experimental conditions on the ferritin immobilization were investigated. The ferritin immobilized on the gold electrode was characterized by atomic force microscopy and cyclic voltammetry.     

A Flow Cell for Use with an Oxygen Membrane Electrode

ABSTRACT

A flow cell was constructed from plexiglass. The cell was designed to allow insertion and removal of a Clark-type oxygen membrane electrode. It was used in a flow system to amperometrically determine glucose and glucose oxidase via oxygen depletion. Hydrogen peroxide was determined by oxidation at +0.9 V vs. the silver/silver chloride electrode by removing the electrode membrane. Alternatively, a lead dioxide catalyst electrode was constructed and inserted into the cell to catalytically decompose hydrogen peroxide to oxygen, which was detected. Molybdenum (VI) was determined by its catalytic effect on the reaction between hydrogen peroxide and thiosulfate.     

一种简便易行的精确测量零件凸面弧长的方法

介绍了一种精确测量零件凸面弧长的较简便易行的方法。将塞尺薄钢片经特殊装夹后用线切割成型,作为测量标尺,用读数显微镜将其校准。之后将该标尺附于要测量的凸面上,再次利用读数显微镜并根据标尺校准值测出凸面弧长。