共查询到20条相似文献，搜索用时 15 毫秒
1.
邵庆龙 《深圳信息职业技术学院学报》2007,5(2):25-31
质子交换膜燃料电池的水管理是影响其性能的重要因素之一。电池水管理的目的就是要实现尽可能高的膜的水合程度,降低膜的阻抗。为了更好实现以上目标,文中建立了电池水传输模型,基于模型利用工程逼近分析方法,分析了阴阳极湿度、反应气体流量对膜的水含量和阴阳极水分压的影响。仿真结果通过与其他模型相比较,取得了一致的结果,因此也证明了该模型的有效和实用性。基于以上的分析结果为建立简化的膜水含量控制模型和实现水管理的控制目标奠定基础。 相似文献
2.
The design methods of anode and cathode are proposed for precision profile grinding.Based on the electrolytic machining theory, electrolytic equilibrium condition and Faraday‘s law of electrolysis are applied to establishing the mathematical model of profile diamond dressing processes. A finite element method (FEM) program is developed to solve the inverse boundary problem of Laplace‘s equation. Desired anode contour or cathode shape is determined by computing the distribution of electric potential layer by layer. Electrolytic machining experiment is carried out to verify the simulated anode shape. The research result shows that shape deviation between designed cathode and profile wheel increases with the value of angle between feed rate and the normal to anode surface. The shape of simulated anode is consistent with the contour of metal-bonded diamond profile wheel for a given cathode. Based on the anode contour, cathode shape can also be designed accurately. 相似文献
3.
In this paper, a 60 kW proton exchange membrane fuel cell (PEMFC) generation system is modeled in order to design the system
parameters and investigate the static and dynamic characteristics for control purposes. To achieve an overall system model,
the system is divided into five modules: the PEMFC stack (anode and cathode flows, membrane hydration, and stack voltage and
power), cathode air supply (air compressor, supply manifold, cooler, and humidifier), anode fuel supply (hydrogen valve and
humidifier), cathode exhaust exit (exit manifold and water return), and power conditioning (DC/DC and DC/AC) modules. Using
a combination of empirical and physical modeling techniques, the model is developed to set the operation conditions of current,
temperature, and cathode and anode gas flows and pressures, which have major impacts on system performance. The current model
is based on a 60 kW PEMFC power plant designed for residential applications and takes account of the electrochemical and thermal
aspects of chemical reactions within the stack as well as flows of reactants across the system. The simulation tests show
that the system model can represent the static and dynamic characteristics of a 60 kW PEMFC generation system, which is mathematically
simple for system parameters and control designs. 相似文献
4.
低电流密度电解金属钕研究 总被引：6，自引：0，他引：6
本文首次介绍了氟化物熔盐体系中在低阴极、阳极电流密度条件下电解制备稀土金属钕的研究情况.结果表明在阴极电流密度为1.39 A/cm2情况下,电解制备金属钕获得了极高的阴极电流效率,且电解电压仅4.8V左右.该研究为下埋阴极稀土金属熔盐电解槽的研究和设计提供了坚实的理论基础.用数据拟合法得到了电解电压与阴极和阳极电流密度之间以及电流效率与阴极电流密度之间的数学关系式. 相似文献
5.
In the current studies a miniature silicon wafer fuel cell （FC） using L-ascorbic acid as fuel was developed. The cell employs L-ascorbic acid and air as reactants and a thin polymer electrolyte as a separator. Inductively coupled plasma （ICP） silicon etching was employed to fabricate high aspect-ratio columns on the silicon substrate to increase the surface area. A thin platinum layer deposited directly on the silicon surface by the sputtering was used as the catalyst layer for L-ascorbic acid electro-oxidation. Cyclic voltammetry shows that the oxidation of L-ascorbic acid on the sputtered platinum layer is irreversible and that the onset potentials for the oxidation of L-ascorbic acid are from 0.27 V to 0.35 V versus an Ag/AgCl reference electrode. It is found that at the room temperature, with 1 mol/L L-ascorbic acid/PBS （phosphate buffered solution） solution pumped to the anode at 1 ml/min flow rate and air spontaneously diffusing to the cathode as the oxidant, the maximum output power density of the cell was 1.95 mW/cm^2 at a current density of 10 mA/cm^2. 相似文献
6.
1 Introduction Direct methanol fuel cell ( DMFC) is desirable toserve as the power systemfor portable devices such ascellular phones , portable computers ,etc. due to thetheoretically high energy density and the liquid fuelused that can be stored and tran… 相似文献
7.
Huang Minsheng 《上海大学学报(英文版)》1998,2(4):316-319
Ｓｔｒｕｃｔｕｒｅ ｏｎ Ｄｅｎｉｔｒｉｆｉｃａｔｉｏｎ ｉｎ ａ Ｂｉｏ－ｅｌｅｃｔｒｏｄｅ ＲｅａｃｔｏｒTX１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｅｎｓｉｖｅａｇｒｉｃｕｌｔｕｒｅａｎｄｉｎｄｕｓｔｒｉａｌｗａｓｔｅｗａｔｅｒｄｉｓ－ｃｈａｒｇｅｄｈａ... 相似文献
8.
固体氧化物燃料电池的研究进展 总被引：1，自引：0，他引：1
文章介绍了几种主要燃料电池的发展和研究现状、固体氧化物燃料电池(SOFC)的工作原理和特点,综述了SOFC的主要组件(阴极、阳极、电解质材料)制备方法及其进展,对SOFC在能源开发利用与市场化的前景进行了展望。 相似文献
9.
钱玲 《连云港职业技术学院学报》2001,14(4):15-16,20
在隔膜电解法制乙醛酸的研究中，采用性能优越的阳极材料钛基氧化铱电极，并对电解工艺等进行改进，在此条件下电解草酸，乙醛酸的产率达90．7％，电流效率82．4％。 相似文献
10.
为了得到碳纳米管场发射器件的三极结构,设计了一种新型栅极.在电极的制作过程中使用普通的丝网印刷方法,然后运用化学刻蚀的手段进行双面刻蚀制备出带有小孔阵列的栅极.在栅极制作过程中通过改变酸液刻蚀的时间和浓度,可以腐蚀出不同形状的小孔.运用扫描电镜(SEM)和红外光谱(IR)分析,得到小孔的尺寸、形貌和刻蚀液的成份,然后在三极结构上加电压显示出孔的亮度图像,最后对器件结构进行模拟,算出在电场条件下的电子从阴极拉到阳极基板的轨迹.模拟结果和实验结果一致,从而实现了对场发射三极器件的优化. 相似文献
11.
This research investigated students' understanding of electrochemistry following a 7–9-week course of instruction. A list of conceptual and propositional knowledge statements was formulated, and this provided the framework for semistructured interviews that were conducted with 32 students in their final year of high school chemistry, following instruction in electrochemistry. Three misconceptions identified in this study and five which have been reported earlier are incorporated into an alternative framework about electric current. The framework is grounded on the notion that a current always involves drifting electrons, even in solution. Another area where students' misconceptions were prevalent was in relation to the sign of the anode and cathode. Students who thought the anode was negatively charged believed cations would move toward it, and those who thought it was positively charged were unable to explain why electrons move away from it. Electrolytic cells also proved troublesome for students. Many students did not associate the positions of the anode and cathode with the polarity of the applied electromotive force (e.m.f.). Other students attempted to reverse features of electrochemical cells and apply the reversals to electrolytic cells. The implications of the research relate to students' interpretation of the language that is used to describe scientific phenomena and the tendency for students to overgeneralize, due to comments made by teachers or statements in textbooks. 相似文献
12.
用于海底管线阴极保护的镯式铝基牺牲阳极,由于其必须适应海底这种高腐蚀性的服役条件,所以对它的制造技术含量要求是很高的。通过对海底管线的阴极保护腐蚀保护系统、镯式阳极的模具设计、浇注方法、质量控制、镯式阳极的安装技术等的论述,突显出镯式铝基牺牲阳极制造工艺技术的特点与新点,以实现海底管线有效防腐之目的。 相似文献
13.
NomenclatureA-area ( m2)Dw-membrane water diffusivity ( m2/s)F-=96 487I-current (A)M-molecule mass (kg/mol)T-temperature (K)W-mass flowrate (kg/s)cw-water concentration in membrane ( mol/m3)m-mass (kg)n-cell numbernd-electro-osmotic drag coefficientp-pres… 相似文献
14.
Emission characteristics of top emitting organic light-emitting devices (TOLEDs) with Ag as reflective anode, Al/Ag as semitransparent
cathode and 90–160 nm [N-(1-naphthy1)-N-pheny1-amino] bipheny1/tris-(8-hydroxy quinoline) aluminum (NPB/Alq3) sandwiched in the electrodes are examined. The electroluminescence (EL) spectra of the TOLEDs are simulated based on the
Fabry-Perot cavity theory. And the resonant modes in cavity structure of TOLEDs is discussed and clarified which can accurately
describe the work principle of the devices. A fairly good match between calculated values and experimental data is achieved
at different emission colors from bluish green to orange. 相似文献
15.
采用陶瓷薄膜技术及溶胶一凝胶法制备了氧离子传导YSZ（Y2O3稳定的ZrO2）电解膜与电极催化剂,构建了膜电极组装（MEA）及结构为H2S、（复合MoS2阳极）／YSZ传导膜／（复合NiO阴极）、空气燃料电池系统;通过在MoS2中掺杂NiS、电解质、Ag粉和淀粉制备了双金属复合MoS2阳极催化剂,在NiO中添加电解质、Ag粉和淀粉制备了复合NiO阴极催化剂：考察了不同操作温度对电池性能的影响,比较了几种不同电极催化剂的性能,研究了H2S／air固体氧化物燃料电池的电化学性能。实验结果表明,在H2S环境中,复合MoS2阳极催化剂比MoS2和Pt具有更好的性能,复合Nio阴极Pt阴极的极化小;在电极催化剂中加入Ag可显著提高电极的导电性．添加电解质和淀粉可以提高电极的离子传导性和多孔性：操作温度增加．传导膜的电传导率和电化学反应速率增加,电池的输出电流与功率密度增加,电化学性能变好。电池连续运行1～4d几乎不降级。在850℃和101．13kPa时．燃料电池最大输出功率密度为155mW·cm^-2,对应的电流密度为240mA·cm^-2。 相似文献
16.
Factors that prevent learning in electrochemistry 总被引：1，自引：0，他引：1
Electrochemistry plays an important role in curricula, textbooks, and in everyday life. The purpose of the present study was to identify and understand secondary‐school students' problems in learning electrochemistry at an introductory chemistry level. The investigation covered four areas: (a) electrolytes, (b) transport of electric charges in electrolyte solutions, (c) the anode and the cathode, and (d) the minus and plus poles. Written tests were given to high‐school students in five cycles. The population from which random samples were drawn totalled 15,700 subjects. Students were asked to select the correct answers and to justify their choices. It was found that students based their reasoning on four alternative concepts: (a) During electrolysis, the electric current produces ions; (b) electrons migrate through the solution from one electrode to the other; (c) the cathode is always the minus pole, the anode the plus pole; and (d) the plus and minus poles carry charges. The results suggest a teaching strategy in which students first experience and learn about electrochemistry concepts. In the second step, appropriate concept terms are added, and students then are confronted with the alternative concepts described in this article. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 258–283, 2007 相似文献
17.
18.
章介绍了具有合成H2O2和光催化性能的双功能新型复合电极，并用X－射线衍射，SEM等方法进行了表征，双功能复合电极是将TiO2/C光催化剂负载在具有合成H2O2性能的新型载体上形成的，在光反应器中，复合电极作阴，钌－钛不溶性电极作阳极，低压汞灯作光源，实现了光化学氧化与光催化氧化在同一电极／溶液界面上的联合作用，实验结果表明，复合电极对提高偶氮染料分子活性艳红（K－2BP）的氧化降解速度起到了重要作用，仅反应3min，脱色率可达49％，80min，偶氮染料分子可降解47％。 相似文献
19.
固定阴极电化学射孔的成型规律研究 总被引：1，自引：0，他引：1
根据电场理论,提出了一种研究固定阴极电化学射孔成型规律的更为严密的处理方法, 且基于这种思路分析了该加工方式下阴极表面电荷密度及加工区电场强度、电流密度、加工速度等在加工过程中的变化规律,建立了加工中间隙变化的数学模型,并给出了相关的实验结果,为这种简易加工方式的合理应用提供了理论依据.,A kind of new idea based on electromagnetic theory is presented, and it is used in research of the shaping law of electrochemical perforation with fixed cathode. The changing laws of the electric field vectors at certain point on the surface of the anode workpiece with machining time, such as the electric field intensity E, the current density j and so on, are introduced. The mathematical model of the perforating velocity is presented, moreover, the experimental result to verify it is given at the end of the paper. 相似文献
20.
殷丽燕 《辽宁科技学院学报》2014,16(4):30-32
利用电化学技术,以试样为阳极,白金为阴极,进行电解,根据试样同参比电极之间的电位差随时间变化的曲线得出溶解反应的终点,从而求出铬、氧化铬溶解所需的电量,根据法拉第定律计算出镀层的重量;根据电解法的校准系数K得到镀铬板的氧化铬。通过实际生产试样进行电解法与化学法的比对,检测精度满足生产要求。 相似文献