15,541 research outputs found
Valley filter in strain engineered graphene
We propose a simple, yet highly efficient and robust device for producing
valley polarized current in graphene. The device comprises of two distinct
components; a region of uniform uniaxial strain, adjacent to an out-of-plane
magnetic barrier configuration formed by patterned ferromagnetic gates. We show
that when the amount of strain, magnetic field strength, and Fermi level are
properly tuned, the output current can be made to consist of only a single
valley contribution. Perfect valley filtering is achievable within
experimentally accessible parameters.Comment: 4 pages, 3 figures; minor corrections, updated Figs. 2 and 3, added
reference
Optical Constants of Silver and Barium in the Vacuum Ultraviolet Spectral Region
Optical constants of silver and barium in vacuum ultraviolet spectral regio
Projection of distributed-collector solar-thermal electric power plant economics to years 1990-2000
A preliminary comparative evaluation of distributed-collector solar thermal power plants was undertaken by projecting power plant economics of selected systems to the 1990 to 2000 time frame. The selected systems include: (1) fixed orientation collectors with concentrating reflectors and vacuum tube absorbers, (2) one axis tracking linear concentrator including parabolic trough and variable slat designs, and (3) two axis tracking parabolic dish systems including concepts with small heat engine-electric generator assemblies at each focal point as well as approaches having steam generators at the focal point with pipeline collection to a central power conversion unit. Comparisons are presented primarily in terms of energy cost and capital cost over a wide range of operating load factors. Sensitvity of energy costs for a range of efficiency and cost of major subsystems/components is presented to delineate critical technological development needs
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