Papers by Keyword: Figure of Merit (FOM)

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Authors: Wang Kee Min, Sung Doo Hwang, Chang Ho Lee, Young Do Park, Yang Do Kim, Young Seok Kim, Ik Min Park, Yong Ho Park
Abstract: The n-type Bi2(Te0.94Se0.06)3 thermoelectric compound was prepared by the direct extrusion process using the powder as raw materials. Hot extruded specimens were annealed at 200°C and 350°C for 2hrs. The electrical conductivity, thermoelectric power and thermal conductivity of hot extruded and annealed specimens were measured at room temperature. The fractographs of the specimens showed that the grain size became coarser and a lot of porosities were generated during annealing process. The power factor value (PF) decreased with increasing the annealing temperature. The electric conductivity and thermal conductivity of the specimens also decreased with the increase of annealing temperature. This may be reasoned that the generated porosities affect the thermal conductivity of the specimens prepared in this study. The figure of merit (Z) value of the annealed specimens at 350°C was improved about 10%. The highest Z value of the specimens annealed at 350°C was 2.0 x 10-3/K among the prepared specimens.
404
Authors: Zi Zheng Guo
Abstract: The magnetostatic interaction, the coercivity and the figure of merit of an irregular triangular nanowire array are studied with the help of Neel model. The results show that the broadening of the distribution of nanowire lengths decreases the thermal stability of the array and the minimum figure of merit is a good candidate for measuring the system’s thermal stability.
233
Authors: Krishna Shenai, Krushal Shah
Abstract: Simple, physics-based, and accurate circuit models are reported for GaN power HEMTs and inductors; these models are then used to design high-performance chip-scale synchronous buck (SB) power converters to provide agile point-of-load (POL) low-voltage ( down to 1V) high-current (up to 10A) power to portable mobile devices from a battery. Excellent agreement between the measured and simulated results is demonstrated for load regulation for a 19V/1.2V, 800 kHz SB converter; for comparison, the same converter performance using the best commercially available state-of-the-art silicon power MOSFETs is also evaluated. It is shown that the conventional approach used for estimating power loss of a SB power converter is in error; a new application-specific Figure of Merit (FOM) for power switches is proposed that accounts for both input and output switching losses.
1307
Authors: Yoshikazu Shimura, Petr Pulpan, Ichiro Fujii, Kouichi Nakashima, Satoshi Wada
Abstract: In this study, a new electric power generation measurement system was developed for piezoelectric energy harvesting using unimorph-type piezoceramics. Relationships between electric power and material constants such as d33, d31, g31, k31, e33T/e0, s11E, Qe and Qm were investigated using various lead zirconium titanate (Pb(Zr,Ti)O3, PZT) ceramics with different material constants. Using the equipment, pulse-type stress was applied to unimorph-type piezoceramics. Then, optimum measurement conditions were determined. Under these conditions, the electric power for piezoelectric energy harvesting was measured as a function of the material constants. Finally, it was clarified that for piezoelectric energy harvesting using a unimorph-type device, the figure of merit was combination of the 3 kinds of material constants such as large d31, small e33T/e0, and large s11E.
173
Authors: Ji Woong Moon, Won Seon Seo, Kunihito Koumoto
87
Authors: Chiharu Ota, Johji Nishio, Tetsuo Hatakeyama, Takashi Shinohe, Kazutoshi Kojima, Shin Ichi Nishizawa, Hiromichi Ohashi
Abstract: 4H-SiC floating junction Schottky barrier diodes (Super-SBDs) were fabricated. It was found that their properties are closest to the theoretical limitation, defined by the relationship between specific on-state resistance and breakdown voltage of 4H SiC-unipolar devices. They have a p-type floating layer designed as line-and-spacing. The specific on-state resistances of Super-SBDs with a few micrometers of spacing width were found to be nearly equal to those of conventional SBDs without p-type floating layer. The breakdown voltages of Super-SBDs were higher than those of conventional SBDs. Accordingly the properties of Super-SBDs have improved the trade-off between specific on-state resistance and breakdown voltage, and the highest value to date for Baliga’s Figure of Merit (BFOM) has been obtained.
1175
Authors: Hirofumi Kakemoto, Tohru Higuchi, Hajime Shibata, Satoshi Wada, Takaaki Tsurumi
Abstract: beta-FeSi2 films were prepared on Si(001) substrates by the molecular beam epitaxy method using an Fe source. The crystallographic orientation of beta-FeSi2 films on Si(001) substrates were characterized by using x-ray diffraction. Using scanning electron microscopy, surface morphology and film thickness of an oriented sample were observed and estimated. The mobility of beta-FeS2 films on Si(001) substrates was also characterized by Hall measurement at room temperature. The enhancement of figure of merit was evaluated as the functions of mobility and crystallographic orientation of samples.
121
Authors: Hitoshi Kohri, Isao A. Nishida, Ichiro Shiota
381
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