Topic
Power density
About: Power density is a research topic. Over the lifetime, 9534 publications have been published within this topic receiving 197264 citations. The topic is also known as: volumic power & volume power density.
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TL;DR: In this paper, the optimization of TEG module spacing and its spreader thickness as used in a waste heat recovery system is investigated and solved numerically using the finite difference method along with a simplified conjugate gradient method.
103 citations
TL;DR: In this article, an asymmetric supercapacitor with a novel porous carbon nanofiber derived from hypercrosslinked polymers (HCP-CNF) and two-dimensional copper cobalt oxide nanosheets (CCO-NS) as the negative and positive electrodes, respectively, is presented.
103 citations
TL;DR: In this article, an anode-supported hollow-fiber solid oxide fuel cell (SOFC) of diameter 1.7mm has been successfully fabricated using the phase inversion and vacuum assisted coating techniques.
103 citations
TL;DR: Conventional CO2 lasers fail to minimize boundary tissue injury, elimination of thermal injury during intraoperative laser ablation requires that CO2 laser energy be focused to achieve a peak power density greater than 60 kW/mm2, and elimination of Thermal injury can be achieved at a variety of wavelengths, provided that an appropriate energy profile is employed.
102 citations
TL;DR: A high-brightness compact 9 keV electron-impact microfocus x-ray source based on a liquid-gallium-jet anode suitable for laboratory-scale x-rays crystallography and hard x-Ray microscopy is demonstrated.
Abstract: The high brightness of synchrotron sources has enabled a significant growth of crystallography and microscopy in the 10 keV range. 1 Laboratory systems for such studies commonly rely on 8 keV emission from copper rotatinganode x-ray sources. The image quality of the laboratory systems is limited by the low brightness of the compact x-ray source. In the present paper we describe a compact liquidgallium-jet-anode electron-impact microfocus source with potential for three orders of magnitude higher brightness than present compact sources in this energy range. In electron-impact sources a multi-keV electron beam strikes a solid metal anode to produce x-rays via bremsstrahlung and line emission. The x-ray brightness basically scales with the electron-beam power density on the anode. The major factor limiting the brightness is the thermal load capacity of the anode since 99% of the kinetic energy of the electron beam is converted into heat. 2 For microfocus x-ray tubes with circular foci typically less than few tens of micrometers in diameter the maximum e-beam power loading is in the range of 0.4‐0.8 W per electron-beam diameter in micrometers full width at half maximum FWHM of Gaussian beam. 3 This corresponds to an e-beam power density at the anode of approximately 25‐50 kW/mm 2 for a1 0m source. For comparison, larger-spot systems based on modern rotating anodes are limited to 10‐20 kW/mm 2 for short exposures while large-spot stationary anodes usually operate at 1 kW/mm 2 . These numbers are not likely to increase significantly. 4 Angled viewing of a line focus can increase the apparent, but not the actual, power density for large-spot geometries. Here we demonstrate a 9 keV compact microfocus source which shows promise for three orders of magnitude higher brightness than present compact sources by operating at very high e-beam power density. This source is based on a liquid-gallium-jet anode and the spectrum is dominated by gallium line emission at 9.3 keV. The high e-beam power density capacity of this anode type is, in short, due to the different thermal properties of liquid-gallium versus solidmetal anodes and the possibility of a much higher anode speed with a liquid-jet anode. In addition and in contrast to existing techniques, the gallium-jet anode is completely regenerative and is therefore not as sensitive to anode damage as solid anodes. Electron-impact sources based on liquid-jet anodes have previously been demonstrated for 25 keV line emission using solder 5,6 and tin. 7 The high spatial coherence of this source allowed short-exposure-time x-ray phase imaging. 8 Gallium jets have been used as targets for femtosecond laser plasma 9 keV emission, although with much lower average brightness. 9
102 citations