Negative electron affinity photocathodes may have useful applications as electron sources for high-throughput microlithography @A. Baum et al., J. Vac. Sci. Technol. B 15, 2707 ~1997!#. However, the nature of such a system has raised questions about the lifetime and reliability of a cathode during operation. In this article, we report on the lifetime and reliability of cathode operation under v...

Microbial fuel cells (MFC) with 30% wet-proofed air cathodes have previously been optimized to have 4 diffusion layers (DLs) in order to limit oxygen transfer into the anode chamber and optimize performance. Newer MFC designs that allow close electrode spacing have a separator that can also reduce oxygen transfer into the anode chamber, and there are many types of carbon wet-proofed materials a...

Since the discovery of carbon nanotubes (CNTs), researches of field emission display (FED) have been mainly focused on it, because of their high-aspect configuration, low work function, high mechanical stability and high conductivity. For CNTs to become a viable engineering material for FED applications, efficient assembly and integration processes for large size are required that are currently...

A photocathode RF gun was built and it has been operated for beam measurement at SPring-8. The cavity was tested by using high power RF up to 18 MW. The electric field gradient on the cathode reached 127 MW/m. After RF conditioning, a laser pulse was irradiated on a copper cathode and the photo-emitted beam was accelerated up to 2.9 MeV. An effective quantum efficiency of the cathode was obtain...

One factor limiting solid oxide fuel cell (SOFC) performance is the degradation of chromium containing, ferritic stainless steel, interconnects during operation. When chromium-containing steels are used as interconnect materials a chromium oxide layer forms on the surface. Under SOFC operating conditions (Cathode gas 800oC and 2.5-3.1% H2O) chromium ions are vaporized by the cathode gas and red...

In this study, the effect of recycling fuel cell products on the performance of a solid oxide fuel cell and gas turbine (SOFC-GT) hybrid system was investigated. Three types of products recycling are considered: cathode products recycling (CPR), anode products recycling (APR), and both cathode and anode products recycling (BACPR). In the present work,   operating temperature and  limiting curre...

This article presents the results of a numerical study, using computational fluid dynamics (CFD) analysis to investigate the species distribution of proton exchange membrane fuel cells (PEMFCs) with deflected membrane electrode assembly (MEA). These new geometry were examined while employing three-dimensional, single phase, non-isothermal and parallel flow for model of a PEM fuel cell. This num...

Numerical simulations of a hollow cathode with a LaB6 emitter operating at 100 A have been performed for the first time using the 2-D Orificed Cathode (OrCa2D) code. Results for a variety of plasma properties are presented and compared with laboratory measurements. The large size of the device permits peak electron number densities in the cathode interior that are lower than those established i...

In electron beam devices, the voltage applied to the cathode (w.r.t. grid voltage) provides the initial energy for the electrons. Based on the type of electron emission, the electron sources are (mainly) classified into thermionic cathodes and cold cathodes. The power consumption of a cold cathode is smaller than that of a thermionic cathode. The delay time of the electron emission from a cold ...

Polarization, solution-separator, charge transfer, and diffusion resistances of clean and used separator electrode assemblies were examined in microbial fuel cells using current–voltage curves and electrochemical impedance spectroscopy (EIS). Current–voltage curves showed the total resistance was reduced at low cathode potentials. EIS results revealed that at a set cathode potential of 0.3 V di...