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排序方式: 共有984条查询结果,搜索用时 15 毫秒
81.
In this study, hydrothermal upgrading and dewatering of raw tropical peat derived from Pontianak, West Kalimantan-Indonesia was evaluated at temperatures ranging from 150 to 380 °C, a maximum final pressure of 25.1 MPa and a residence time of 30 min. The moisture content of the raw peat was approximately 90 wt.%. Raw peat was hydrothermally upgraded without the addition of water in the laboratory scale. The yield of the solid products was between 53.0 and 99.7 wt.% and the effective calorific value of hydrothermally dewatered peat was between 17,290 and 29,209 kJ/kg following hydrothermal upgrading. In addition, the oxygen content in the solid product was varied from 38.4 to 15.6 wt.% after upgrading, while the carbon content from 55.2 to 77.8 wt.%. The hydrothermally upgraded peat fuel product also had an equilibrium moisture content of 2.3 wt.% and a maximum equilibrium moisture content of 17.6 wt.%. Upgraded peat is characteristically resistant to moisture adsorption at high humidity, which makes it promising for fuel based combustion. The change in the carbon-functional groups and their properties, as determined by FTIR and 13C NMR, are discussed in terms of the hydrothermal upgrading and dewatering process. 相似文献
82.
83.
Sausan Al-Riyami Shinya Ohmagari Tsuyoshi Yoshitake 《Diamond and Related Materials》2010,19(5-6):510-513
Nitrogen-doped ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) films were deposited by pulsed laser deposition (PLD). Nitrogen contents in the films were controlled by varying a ratio in the inflow amount between nitrogen and hydrogen gases. The film doped with a nitrogen content of 7.9 at.% possessed n-type conduction with an electrical conductivity of 18 Ω? 1 cm? 1 at 300 K. X-ray photoemission spectra, which were measured using synchrotron radiation, were decomposed into four component spectra due to sp2, sp3 hybridized carbons, C=N and C–N. A full-width at half-maximum of the sp3 peak was 0.91 eV. This small value is specific to UNCD/a-C:H films. The sp2/(sp3 + sp2) value was enhanced from 32 to 40% with an increase in the nitrogen content from 0 to 7.9 at.%. This increment probably originates from the nitrogen incorporation into an a-C:H matrix and grain boundaries of UNCD crystallites. Since an electrical conductivity of a-C:H does not dramatically enhance for this doping amount according to previous reports, we believe that the electrical conductivity enhancement is predominantly due to the nitrogen incorporation into grain boundaries. 相似文献
84.
85.
Tsuyoshi Nishiwaki Atsushi Yokoyama Zen-ichiro Maekawa Hiroyuki Hamada 《Composite Structures》1995,32(1-4):635-640
Localized impact problems for composite structures have recently become important. In this study, some elastic wave velocities in 7-ply GFRP laminate with [02/903/02] ply orientation after low speed impact was investigated by using both experimental methods and finite element methods. For the finite element simulation, the quasi-three-dimensional model was used. Comparing the results, the validity for the application of this model to the dynamic problem was estimated. Moreover the quasi-three-dimensional model is applied to the GFRP plates with interlaminar delamination. The relationship between the elastic wave velocities and delaminated states is discussed. 相似文献
86.
Jun Sawai Tsuyoshi Nakai † Atsushi Hashimoto & Masaru Shimizu 《International Journal of Food Science & Technology》2004,39(9):967-974
The apparent reaction rate constants (k) of the reaction that generates reducing sugar (presented as mg maltose equivalents) from raw sweet potato starch by using β‐amylase were determined by varying enzyme concentration, starch concentration and pH. The Arrhenius plot of the k‐value reached a peak at approximately 86 °C; the activation energy and frequency factor were also determined. Moreover, the amount of reducing sugar produced in sweet potato heated by infrared irradiation was estimated by using the values of k and the kinetic parameters. The calculated amounts of reducing sugar produced generally agreed with the experimental values. These results indicate that the amount of reducing sugar produced in heat‐treated sweet potato can be predicted by the methodology described in this study. 相似文献
87.
Masahiko Yamada Shoichiro Fukusako Tsuyoshi Kawanami 《International Journal of Refrigeration》2002,25(2)
For the purpose of determining the optimum operation condition of liquid-ice thermal storage system, the performance analysis has been carried out. The target system was consisted of refrigerator, its auxiliary devices, liquid-ice production device, piping system, and thermal load section. The system performances were widely investigated analytically for the variety of operation conditions including the cycle performance of a refrigerator. The optimum operation condition of the liquid-ice thermal storage system from the viewpoint of coefficient of performance and the performance of heat release were discussed. 相似文献
88.
Hidero Unuma Koh Miura Tsuyoshi Furusaki Kohei Kodaira 《Journal of the American Ceramic Society》1991,74(6):1291-1295
Crystallization of Li-Al-Si-O-N oxynitride glasses based on the β-spodumene composition and the properties of the resultant glass-ceramics have been studied. The onset of the precipitation of metastable high-quartz solid solution and its transformation to β-spodumene shift to higher temperatures with increasing nitrogen content of the oxynitride glasses. Nitrided glass-ceramics crystallized at 1200°C have negative thermal expansion coefficients, since high-quartz structure is maintained up to 1000° and 1200°C. Knoop hardness and density of the glass-ceramics increase with increasing nitrogen content. There was evidence that part of the nitrogen atoms were incorporated into the high-quartz solid-solution structure and that a small amount of the minor phase of Si2 N2 O was precipitated in highly nitrided glass-ceramics. 相似文献
89.
90.
Tsuyoshi Saotome Hansang Kim David Lashmore H. Thomas Hahn 《Bulletin of Materials Science》2011,34(4):615-622
We describe in this paper a transparent conducting film (TCF). It is a fibrous layer of multiwalled carbon nanotubes (MWNTs),
labeled a dilute CNT mat, that was prepared and unidirectionally stretched to improve both the optical and electrical properties.
After stretching by 80% strain, transmittance at 550 nm wavelength was improved by 37% and sheet resistance was reduced to
71% of the original value. The improvement of the transmittance can be explained by increased area of the CNT mat after stretch,
and the reduced sheet resistance can be explained by increased density of the CNT alignment in lateral direction due to contraction.
Based on the microscopic observation before and after stretch, models to describe the phenomena are proposed. By further expanding
on this method, it may be possible to obtain a transparent conducting carbon nanotube film which is crack-resistant for solar
cell applications. 相似文献