Effect of Anode Arc Root Position on the Behavior of the DC Non-transferred Plasma Jet at Field Free Region

A special bi-anode plasma torch that can change the anode arc root position without changing working gas flow rate has been developed to investigate the effect of anode arc root position on the behavior of the plasma jet. It has two nozzle-shaped anodes at different axial distances from the cathode tip. The arc root can be formed at anodes either close to the cathode tip (anode I) or far away from it (anode II) to obtain different attachment positions and arc voltages. The characteristics of pure argon plasma jets operated in different anode modes were measured in the field free region by using an emalpy probe, and the thermal efficiency of the torch was determined by measuring the temperature differences between cooling water flowing in and out of the torch. The results show that compared with the normal arc operated in anode I mode, the elongated arc operated in anode II mode significantly reduced the plasma energy loss inside the torch, resulting in a higher temperature and a higher velocity of the plasma jet in the field free region.     

Quantitative depth profiling in glow discharge spectroscopies – A new deconvolution technique to separate effects of an uneven erosion crater shape

An algorithm is presented as a concept for the quantification in direct current and radiofrequency glow discharge (GD) modes for GD optical emission spectroscopy. The algorithm is divided into excitation and sputtering part and thus it is possible to distinguish between the different excitation processes and to consider equivalent sputtering crater formations in both modes. Intensity-time profiles are affected corresponding to the method by several effects. One important effect is that sputtering occurs at a single time in different depths because of curved crater bottoms, this is usually called crater effect. The main purpose is to introduce an iterative deconvolution technique which for the quantification numerically takes into account the curved sputtering crater bottom. Input data for the deconvolution technique are the calibrated mass-time profile, the partial densities of the sample constituents and the measured final shape of the sputtering crater. Using a relatively simple model for ion sputtering the deconvolution technique improves iteratively the calculated layer structure by means of information on crater formation. The mathematical handling is illustrated for the quantification of a depth profile of a multilayer sample of ten 100 nm layers. The resulting concentration-depth profile reflects excellently the real elemental distribution of the multilayer system.     

Thermal expansion, gas permeability, and conductivity of Ni-YSZ anodes produced by different techniques

The supported Ni-YSZ (50 wt.% Ni?+?50 wt.% Zr_0.84Y_0.16O_1.92) anodes were produced of powders, obtained by the ceramic method, combustion synthesis, deposition of nickel oxide onto the YSZ ceramics, and deposition of 28 wt.% of nickel oxide onto the 39 wt.% NiO?+?61 wt.% YSZ powders. The influence of the NiO-YSZ powder production technique, the amount of pore former and sintering temperature on the porosity, gas permeability, thermal expansion, and anode conductivity were studied. The porosity of anodes made of powders obtained by the ceramic method is always lower than the porosity of the anodes made of powders produced by combustion synthesis under otherwise equal conditions. The anode electrical conductivity greatly depends on the powder production techniques, while the anode thermal expansion is only slightly influenced by them.     

基于定向纳米碳管气体放电的气敏传感器研究

介绍了一种基于定向纳米碳管的气敏传感器,以生长定向纳米碳管的氧化铝模板作为阳极,铝板作为阴极,利用纳米碳管的尖端发射效应,在较低的电压下使气体产生放电现象。通过对纳米碳管在气体中击穿电压和放电电流的测量,实现对气体的定性定量检测。同时纳米碳管气敏传感器还具有体积小、灵敏度高、稳定性好、响应速度快、在常温常压下即可进行检测等优点,具有较好的应用前景。     

Dependence of Performance of Organic Light-emitting Devices on Sheet Resistance of Indium-tin-oxide Anodes

IntroductionIndium-tin-oxide(ITO) has been widely used asthe anode material in organic light-emitting devices(OLEDs) because of its high transmittance in the visi-ble region and low electrical resistivity. In the pastyears, many investigations focused on …     

Modifying argon glow discharges by hydrogen addition: effects on analytical characteristics of optical emission and mass spectrometry detection modes

An overview of the effects produced by the presence of hydrogen in a glow discharge (GD), generated either in argon or in neon, is given. Extensive work related to the addition of hydrogen to GDs, coupled with optical emission spectrometry (OES) and mass spectrometry (MS), has been published in the last few years in an attempt to explain the processes involved in the discharge of mixed gases. Although numerous experimental results have already been explained theoretically, a complete understanding of the effects brought about by mixing hydrogen with argon (or another discharge inert gas) has not been reported yet. The use of theoretical models implemented using a computer has allowed the importance of some collisional and radiative processes in the inert gas plasma when hydrogen is present to be evaluated. This review shows, however, that both experimental work and theoretical work are still needed. The influence of small quantities of hydrogen on discharge parameters, such as electrical current or dc bias voltage, on crater shapes and on sputtering rates is thoroughly reviewed along with the effect on the analytical signals measured by OES and MS. Also, hydrogen-effect corrections needed to carry out proper calibrations for direct solid quantitative analyses are discussed. Figure Hydrogen induced changes in the Ar glow discharge reactions.     

Study of a pulsed glow discharge ion source for time-of-flight mass spectrometry

This paper describes a new type of glow discharge (GD) ion source coupled to a time-of-flight mass spectrometer (TOFMS). The GD is operated in the microsecond pulse (μs-pulse) mode. The operational parameters of the μs-pulse GD were optimized against the ion signals, giving 180 Pa for the discharge pressure, 3 A for the transient discharge current, 1.75 kHz for the discharge frequency and 2 μs for the discharge pulse duration. Experimental results show that the discharge current in the μs-pulse mode can be one order of magnitude higher than that obtained in the d.c. mode. The structure of the interface between the μs-pulse GD and the mass spectrometer was found to be critical, and a Macor disc must be applied in front of the sampling orifice in order to shield the sampling plate from the anode of the GD to achieve both a good vacuum and the best sputtering. A transient sputtering rate of 24.4 μs s⁻¹ mm⁻² was reached in the μs-pulse mode and was significantly higher than that for the d.c.-GD. Typical mass spectra of brass and nickel samples were studied and are discussed. © 1997 Elsevier Science B.V.     

低浓度干甲烷在SOFC Ni-YSZ阳极上的反应

向Ni-YSZ/YSZ/LSM(Ni-Y2O3稳定的ZrO/YSZ/La0.85Sr0.15MnO3-δ)电池阳极通入不同浓度的干甲烷,利用气相色谱对阳极尾气进行原位检测,研究在不同电流密度下,干甲烷在Ni-YSZ阳极上所发生的反应.通过理论开路电压和实测开路电压的比较、阳极尾气的定量分析以及CH4在Ni基阳极上基元反...     

微生物阳极燃料电池极性反转现象研究

本文在构建出微生物阳极燃料电池系统的基础上,研究了微生物燃料电池极性反转现象. 实验表明,由活性污泥混合菌源接种的微生物阳极在电极表面形成电化学生物膜,但平行构建的微生物阳极燃料电池系统在内阻、输出电压和放电时长等方面存在着不同程度差异. 在串联微生物燃料电池组中,放电操作会导致性能较差的微生物单电池首先出现极性反转. 电极电势测量表明,较高的放电电流使微生物阳极电势迅速正移,导致电池系统出现极性反转. 在室温范围内,温度升高可使MFC承受较高的放电电流,不易发生极化. 燃料物质缺乏时,MFC易发生极性反转,但过高的电流仍能使燃料物质充分的MFC出现极性反转. MFC极性反转会对微生物阳极性能造成影响. 极性反转时间较短(<5 min),对微生物阳极影响不大,但延长极性反转时间,会导致微生物阳极性能下降.     

混合金属氧化物阳极在海水中的电化学性能

采用热分解方法制备钛基混合金属氧化物阳极 ,用扫描电镜对阳极涂层显微形貌进行了分析 ,并通过实海模拟试验考察了混合金属氧化物阳极在海水阴极保护系统中的使用性能 .SEM分析结果表明 ,混合金属氧化物阳极涂层呈多孔多裂纹的显微结构 ,与其它阳极材料相比 ,此种阳极具有更大的活性表面积 .电化学试验结果表明 ,混合金属氧化物阳极在海水中具有良好的电化学稳定性和电化学活性 ;此外 ,混合金属氧化物阳极在海水中的消耗率很低 ,属于不溶性的阳极材料 ,作为外加电流阴极保护的辅助阳极具有广泛的应用前景     

Studying the Link between the Potential of a Metal-Oxide Anode, the Current Efficiency for Chlorate, and the Current Losses for the Oxygen and Chlorine Evolution in a Wide Range of the Chlorate Electrolysis Conditions

Dependences of the current efficiency for chlorate and current losses for the oxygen evolution on the anode potential are studied. The study is performed in a cell without directed electrolyte circulation during the electrolysis of chloride–chlorate solutions of various compositions at the ORTA and ORTA-I1 anodes, at different current densities, temperatures, and solution pH. At identical temperatures, the dependences have extremums. The anode potentials corresponding to extremums coincide with critical potentials (found in a polarization study) for anodes covered with coatings containing ruthenium dioxide. The current efficiency for chlorate at ORTA-I1 is higher than that at ORTA, while the extremum region is less pronounced. The problem of how to substantially decrease the specific power consumption in the chlorate production by simultaneously increasing the anodic current density and the electrolysis temperature is considered.     

低温海水用钛基金属氧化物阳极的制备与性能

将Ti N纳米粉体与Ta Cl5正丁醇饱和溶液混合制得中间层涂覆液,通过热分解法在不同焙烧温度下得到了含有中间层的Ti/(Ti-Tax)O2/Ir O2电极,并与相同工艺下得到的传统Ti/Ir O2电极进行对比分析.采用X射线衍射和扫描电子显微镜对制备的电极进行了表征,通过循环伏安曲线、极化曲线和恒流加速寿命测试等电化学手段对电极性能进行了分析.结果表明,引入中间层可以使Ti/(Ti-Tax)O2/Ir O2电极400℃低温焙烧样品表层Ir O2结晶发育更好,得到了通常高温下才具有的典型龟裂纹形貌;相对于500℃高温焙烧样品,其在海水中的电化学活性表面积提高近6倍,在4℃和100 m A/cm2电流密度下的电极电位(1.37 V)降低100 m V,催化性能得到显著提高;同时加速寿命相对于传统的Ti/Ir O2电极提高10倍以上,是一种适用于低温海水环境的、具有较高活性和耐久性的新型阳极.     

Bismuth Nanoparticles Anchored on Ti3C2Tx MXene Nanosheets for High-Performance Sodium-Ion Batteries

Sodium-ion batteries are promising energy-storage systems, but they are facing huge challenges for developing fast-charging anode materials. Bismuth (Bi)-based anode materials are considered as candidates for fast-charging anodes of sodium-ion batteries due to their excellent rate performance. Herein, we designed a two-dimensional Bi/MXene anode material based on a hydrogen thermal reduction strategy. Benefitting from microstructure advantages, Bi/MXene anodes exhibited an excellent rate capability and superior cycle performance in Na//Bi/MXene half-batteries and Na₃V₂(PO₄)₃/C//Bi/MXene full-batteries. Moreover, full-batteries can complete a charge/discharge cycle in 7 min and maintain an excellent cycle life (over 7000 cycles). The electrochemical test results showed that Bi/MXene is a promising anode material with fast charge/discharge capability for sodium-ion batteries.     

F-和Fe3+掺杂对Ti基PbO2阳极性能的影响

采用热分解-电镀法制备了Ti基PbO2,阳极(Ti/PbO2),F-掺杂PbO2阳极(Ti/F-PbO2),Fe3+掺杂PbO2阳极(TiP/Fe-PbO2)和F-,Fe3+共掺杂PbO2,阳极(Ti/F-Fe-PbO2).采用XRD和EDX测试对电极进行了表征,应用加速电解寿命测试和电催化降解4-氯苯酚(4-CP)污水,考察了F-掺杂,Fe3+掺杂和F-,Fe3+共掺杂对PbO2阳极稳定性及电催化活性的影响.结果表明,Ti/F-PbO2和Ti/FePbO2阳极有相近的电催化降解活性,但与Fe3+掺杂相比,F-掺杂大大提高了PbO2阳极的加速电解寿命.对Ti/F-Fe-PbO2阳极,Fe3+掺杂改善了其导电性能.同时F-掺杂提高了阳极的稳定性能,使其有较长的电解寿命.与Ti/PbO2,Ti/F-PbO2和Ti/Fe-PbO2阳极相比,Ti/F-Fe-PbO2阳极的电催化降解活性显著提高,这不仅与其导电性能的改善有关,更与F-掺杂和Fe3+掺杂对4-CP降解的表面协同作用有关.     

Wachstum dünner Fluorkohlenstoffschichten auf der Anode einer Glühkathodenentladung

The polymerization of tetrafluorethylene on the anode of a hot glow discharge has been investigated. Rates of polymer deposition have been measured as a function of monomer pressure, discharge current density, and electrode surface temperature. A mechanism of polymer formation is suggested. The results are different from those obtained by polymerization of the same monomer in a glow discharge. It is concluded that negative ions have a great influence on mechanism of polymer formation. Additionally, monomer molecules adsorbed at the electrode are polymerized by electron bombardment.     

LSGMC5含量对于二甲醚燃料电池复合Ni-Fe阳极性能的影响

用浸渍法制备了掺杂不同质量分数的La0.8Sr0.2Ga0.8Mg0.15Co0.05O3-δ (LSGMC5)粉末的Ni8-Fe2-LSGMC5复合阳极, 并采用交流阻抗和直流极化技术考察了以氢气和二甲醚为燃气时该复合阳极的电化学性能及相应电池的功率输出特性. 结果表明, 在电极中掺入LSGMC5 粉末, 能显著地改善电极的形貌和电极/电解质界面结构, 减小欧姆电阻和极化电阻. 电极中LSGMC5 粉末含量对于氢气及二甲醚电化学氧化性能的影响显著不同. 以二甲醚为燃气时, 电极极化电阻随LSGMC5 粉末含量的增加而减小, 其中LSGMC5 掺杂量为30%的复合阳极具有最高的电化学性能, 相应电池在1073、1023、973 K 时的输出功率分别为1.00、0.61、0.40 W·cm-2; 以氢气为燃气时, LSGMC5 掺杂量为20%的复合阳极具有最好的电化学性能, 随着LSGMC5 掺杂量的进一步增加, 电极极化电阻显著增大.     

Development of an Atmospheric Pressure Glow Discharge Detector for Capillary Column Gas Chromatography

 The use of the change in the oscillation frequency of the current of a new atmospheric helium glow discharge for sensitive signal detection for gas chromatography is studied. The effluent of a capillary column is directed into the glow discharge cell perpendicular to the axis of the glow discharge that existed between a platinum anode and cathode. A stable discharge is obtained when several hundred volts are applied between the 0.2-mm gap between the anode and cathode. The effects of the electrode gap, discharge voltage and gas flow rate on the baseline frequency and discharge current were investigated. The chromatogram shows that the discharge current and discharge gap have a strong influence on the detector response. The discharge current shows positive peaks; however, frequency peaks are positive or negative depending on the discharge conditions. The response of the detector is in the femto-mole and pico-mole range for nonane and decane. Received August 5, 1997. Revision September 2, 1999     

Determination of Minor Aluminum and Nickel in Brass Sample with Magnetic Field Enhanced Glow Discharge Optical Emission Spectrometry

Glow discharge atomic spectrometry, includes principally glow discharge optical emission spectrometry (GD-OES) and GD mass spectrometry, has been widely applied in direct solid sample determination and surface depth analysis. There have been numerous methods adopted to enhance the emission signal in a GD-OES without losing the advantage of narrow spectral lines by using what is known as boosted GD sources, especially microwave discharge and magnetic field enhanced techniques. The addition of a magnetic field to the GD volume is an attractive option because it does not require much modification to the original source configuration, in addition,the presence of magnetic field lengths the drift path of electrons from plasma region to the anode,and therefore strengthens the sputtering, excitation, and ionization processes that good for signal generation.