Plasma and electrode emissions from a 1 kW hydrogen-nitrogen arcjet thruster

Arc root behavior affects the energy transfer and nozzle erosion in an arcjet thruster. To investigate the development of arc root attachment in 1 kW class N2 and H2-N2 arcjet thrusters from the time of ignition to the stably working condition, a kinetic series of end-on view images of the nozzle obtained by a high-speed video camera was analyzed. The addition of hydrogen leads to higher arc voltage levels and the determining factor for the mode of arc root attachment was found to be the nozzle temperature. At lower nozzle temperatures, constricted type attachment with unstable motions of the arc root was observed, while a fully diffused and stable arc root was observed at elevated nozzle temperatures.

Synthesis and field emission of diamond-like carbon nanorods on TiO2/Ti nanotube arrays

Highly ordered TiO2/Ti nanotube arrays were fabricated by anodic oxidation method in 0.5 wt% HF. Using prepared TiO2/Ti nanotube arrays deposited Ni nanoparticles as substrate, high quality diamond-like carbon nanorods (DLCNRs) were synthesized by a conventional method of chemical vapor deposition at 750 degrees C in nitrogen atmosphere. DLCNRs were analyzed by filed emission scanning electron microscopy and Raman spectrometer. It is very interesting that DLCNRs possess pagoda shape with the length of 3-10 mu m. Raman spectra show two strong peaks about 1332 cm (1) and 1598 cm (1), indicating the formation of diamond-like carbon. The field emission measurements suggest that DLCNRs/TiO2/Ti has excellent field emission properties, a low turn-on field about 3.0 V/mu m, no evident decay at 3.4 mA/cm(2) in 480 min. (C) 2009 Elsevier B. V. All rights reserved.

Composite electrode for unitized regenerative proton exchange membrane fuel cell with improved cycle life

To improve the cycle life of unitized regenerative fuel cells (URFCs), an electrode with a composite structure has been developed. The cycle life and polarization curves for both fuel cell and electrolysis modes of URFC operation were investigated. The cycle life of URFCs was improved considerably and the performance was fairly constant during 25 cycles, which illustrates that the composite electrode is effective in sustaining the cyclic performance of URFCs. It shows the URFCs with such an electrode structure are promising for practical applications. (C) 2004 The Electrochemical Society.

The study on a PVC membrane electrode for gemfibrozil

In this paper, a poly(vinyl chloride) (PVC) membrane electrode is prepared for gemfibrozil, 2, 2-dimethyl-5(2,5-xylyloxy) valeric acid, based on its ion pair complexes with hexadecyltrioctyl ammonium iodide (HTOA). The membrane composition of the electrode was optimized by using the sequential level elimination method for orthogonal experimental design. The electrode has a Nernstian response range from 2.5 X 10(-5) to 0.1 mol/l with an average slope of 55.3 mV/decade. The limit of detection is 7.1 X 10(-6) mol/l. The electrode responses were not affected by pH in the range 10.0-12.3. A Na2B4O7-Na2CO3 buffer of pH = 11.0 was selected as the background electrolyte solution for potentiometric measurements. The electrode was used for determining gemfibrozil in pharmaceutical preparations with satisfactory results.

Calibration of a solid-state copper ion-selective electrode in cupric ion buffers containing chloride

It is shown that near-Nernstian calibration slopes can be obtained with a Cu1.8Se electrode in a range of cupric ion buffers in spite of a high chloride content. Best results are obtained with the ligands ethylenediamine, glycine and histidine. The onset of cupric ion toxicity towards marine organisms falls within the pCu calibration range obtained with glycine, and the Cu1.8Se electrode could, therefore, be useful for monitoring cupric ion activity in bioassays in sea-water media.

A biofuel cell with enhanced performance by multilayer biocatalyst immobilized on highly ordered macroporous electrode

A one-compartment glucose/O-2. biofuel cell based on an electrostatic layer-by-layer (LbL) technique on three-dimensional ordered macroporous (3DOM) gold electrode was described. A 3DOM gold electrode was synthesized electrochemically by an inverted colloidal crystal template technique. Then the macroporous gold electrodes were functionalized with Au nanoparticles (AuNPs) and enzyme, glucose dehydrogenase (GDH) or laccase.