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971.
Samar K. Guha Hirokazu Kobayashi Kenji Hara Hiroto Kikuchi Tsutomu Aritsuka Atsushi Fukuoka 《Catalysis communications》2011,12(11):980-983
Sugar beet fiber is an agricultural by-product in the sugar manufacturing and an available biomass source with a rich hemicellulose component. So far, there has been no report on the catalytic conversion of the beet fiber for the synthesis of chemicals. In this work, the hydrogenolysis of the beet fiber was studied by using supported metal catalysts under pressurized hydrogen conditions. Activated carbon supported Ru was found to show the highest catalytic activity to give arabitol as a major product in the hydrogenolysis of hemicellulose part of this material. The reuse ability of the catalyst was also investigated. 相似文献
972.
Okano K Yu D Matsui A Maezawa Y Hosokawa Y Kira A Matsubara M Liau I Tsubokawa H Masuhara H 《Chembiochem : a European journal of chemical biology》2011,12(5):795-801
This article describes a novel laser-directed microfabrication method carried out in aqueous solution for the organization of cell networks on a platform. A femtosecond (fs) laser was applied to a platform culturing PC12, HeLa, or normal human astrocyte (NHA) cells to manipulate them and to facilitate mutual connections. By applying an fs-laser-induced impulsive force, cells were detached from their original location on the plate, and translocated onto microfabricated cell-adhesive domains that were surrounded with a cell-repellent perfluoroalkyl (R(f)) polymer. Then the fs-laser pulse-train was applied to the R(f) polymer surface to modify the cell-repellent surface, and to make cell-adhesive channels of several μm in width between each cell-adhesive domain. PC12 cells elongated along the channels and made contact with others cells. HeLa and NHA cells also migrated along the channels and connected to the other cells. Surface analysis by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that the R(f) polymer was partially decomposed. The method presented here could contribute not only to the study of developing networks of neuronal, glial, and capillary cells, but also to the quantitative analysis of nerve function. 相似文献
973.
Takeshi Yamaguchi Junji AndoTakuya Tsuda Naoko TakahashiMamoru Tohyama Atsushi MuraseToshihide Ohmori Kazuo Hokkirigawa 《Tribology International》2011,44(11):1296-1303
In this study we investigated the sliding velocity dependency of the coefficient of friction for a Si-containing diamond-like carbon (DLC-Si) film in an automatic transmission fluid (ATF) under a wide range of contact pressures. The DLC-Si film and a nitrided steel with a surface roughness, RzJIS, of around 3.0 μm were used as disk specimens. A high-carbon chromium steel (JIS-SUJ2) bearing ball was used as a ball specimen. Friction tests were conducted using a ball-on-disk friction apparatus under a wide range of sliding velocites (0.1-2.0 m/s) and contact pressures (Pmax: 0.42-3.61 GPa) in ATF. The friction coefficients for the nitrided steel had a tendency to decrease with an increase in sliding veloicity under all the contact pressure conditions; however, the friction coefficients for the DLC-Si film were stable with respect to sliding velocities under all the contatct pressures. These results indicate that the DLC-Si film suppresses the stick-slip motion during sliding againt steel in ATF, which is a desired frictional characteristic for the electromagnetic clutch disks used under lubrication. Furthermore, the DLC-Si film showed a higher wear resistance and lower aggression on the steel ball specimen than the nitrided steel. There were less hydrodynamic effects on the friction coefficient for the DLC-Si film possibly due to maintenance of the initial surface roughness and its poorer wettability with the fluid. X-ray photoelectron spectroscopy (XPS) analysis of the sliding surfaces revealed that the adsorption film derived from the succinimide on the sliding surfaces of the DLC-Si film and the mating steel ball also contributed to the sufficient and less sliding-velocity-dependant friction coefficients. 相似文献
974.
975.
Gain scheduling control of variable speed WTG under widely varying turbulence loading 总被引:2,自引:0,他引:2
Endusa Billy Muhando Tomonobu Senjyu Naomitsu Urasaki Atsushi Yona Hiroshi Kinjo Toshihisa Funabashi 《Renewable Energy》2007,32(14):2407-2423
Probabilistic paradigms for wind turbine controller design have been gaining attention. Motivation derives from the need to replace outdated empirical-based designs with more physically relevant models. This paper proposes an adaptive controller in the form of a linear quadratic Gaussian (LQG) for control of a stall-regulated, variable speed wind turbine generator (WTG). In the control scheme, the strategy is twofold: maximization of energy captured from the wind and minimization of the damage caused by mechanical fatigue due to variation of torque peaks generated by wind gusts. Estimated aerodynamic torque and rotational speed are used to determine the most favorable control strategy to stabilize the plant at all operating points (OPs). The performance of the proposed controller is compared with the classical proportional-integral-derivative (PID) controller. The LQG is seen to be significantly more efficient especially in the alleviation of high aerodynamic torque variations and hence mechanical stresses on the plant drive train. Simulation results validate the effectiveness of the proposed method. 相似文献
976.
Ryutaro?MinamiEmail author Tsuyoshi?Kariya Tsuyoshi?Imai Yoshika?Mitsunaka Keishi?Sakamoto 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(3):311-319
A high efficiency quasi-optical (QO) mode converter for high-power, low-frequency gyrotron have been designed and tested.
For low-frequency gyrotrons, the scales of the mode converter are comparatively small on the wavelength scale, thus causing
significant diffraction losses. Over-1 MW power gyrotron with TE8,3 cavity at 28 GHz have been developed, which has a high efficiency mode converter designed by the use of numerical methods
for launcher optimization. This calculation is sufficiently optimized to maximize the fractional Gaussian content of the far
field. The total transmission efficiency from the mode converter to output window is 94.7%. For the experimental result of
first tube, the output power of more than 1 MW has been obtained with about 40% efficiency and output burn pattern agrees
fairly with the calculated profiles, which imply the design appropriateness. Besides, the frequency dependence for diffraction
loss is discussed, and these results give the guiding design principle of the mode converter for high-power, low-frequency
and long-pulse gyrotrons. 相似文献
977.
Atsushi Doi Fran?ois Blanchard Tomoko Tanaka Koichiro Tanaka 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(8-9):1043-1051
Terahertz (THz) wave imaging for biomaterial samples such as cells requires real-time acquisition and high spatial resolution beyond the diffraction limit. The existing THz near-field microscopes are based on raster-scanning techniques, and are therefore not able to image and trace morphological changes in a large area. With the recent advances in high-power THz sources, we demonstrated how to achieve high spatial resolution over a large size using a conventional charge-coupled-device (CCD) camera with the electro?Coptic (EO) sampling technique. In this paper, we determine a limiting factor that restricts spatial resolution in our near-field microscope. By calculating the imaging performance of the probe beam together with THz wave diffraction, we show that the most relevant factor is the diffraction inside the EO crystal. Near-field imaging of metal patterns using EO crystals with different thicknesses supports this calculation. A thin EO crystal is essential for achieving THz images with high spatial resolution. 相似文献
978.
Tadaaki Matsumura Kazuki Nakano Ryoji Kanno Atsushi Hirano Nobuyuki Imanishi Yasuo Takeda 《Journal of power sources》2007
The nickel sulfide, Ni3S2, was examined as a potential cathode material of the all-solid-state-lithium-batteries using thio-LISICON, Li2S–GeS2–P2S5, as the solid-electrolyte. Ni3S2and Li2S–GeS2–P2S5 system, was synthesized with a new sintering system, which proceed under a flowing argon in the reusable quartz tube. The highest ionic conductivity 2.39×10−3 S cm−1 was observed for a sample prepared at 700 °C with 10% of excess P2S5, and bear comparison with the maximum conductivity reported for the thio-LISICON, Li3.35Ge0.35P0.65S4. An all-solid-state-lithium-battery based on, Ni3S2/Li3.35Ge0.35P0.65S4/Li–Al alloy, showed electrochemical capacities of greater than ∼300 mAh g−1 after 30 cycles. The cycling performances of the cells were found to be dependent on the Ni3S2/thio-LISICON compositions in the cathode mixture, with a cell containing 60 wt.% of Ni3S2 exhibiting the most stable reversible capacities. As the depth of the first discharge capacity also influences the cycling properties, Ni3S2 consumed during the discharge reaction may play an important role in the nickel reduction mechanism. 相似文献
979.
A fundamental study on solidifying phenomenon in a rectangular space filled with water‐saturated porous medium has been carried out with a system, cooled from the upper boundary and heated from below, where vigorous convection develops in the un‐solidified liquid layer. The dynamic response of the solid‐liquid interface to the periodical cooling temperature with the bottom boundary kept at constant temperature TH = 20°C, is investigated experimentally. In particular, the amplitude of the interface and the phase lag in respect to the oscillating cooling temperature have been monitored for various periods and average temperatures. A one‐dimensional numerical model, based on an assumption of constant heat flux from the vigorously convecting liquid regime has been also developed. The numerical model predicts quite well the time‐dependent behavior of the horizontally averaged ice‐layer thickness observed in the experiments. Our general findings are that the amplitude increases proportionally to the temperature fluctuation period and that both the thicker solid layer and the shorter period cause greater phase lags. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(4): 294–308, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20109 相似文献
980.
We have fabricated Eu3+-doped ZnO (ZnO:Eu) nanocrystals (NCs) by a reverse micelle method, and have studied their photoluminescence (PL) properties in vacuum, nitrogen gas, and oxygen gas atmospheres. The ZnO:Eu NCs exhibit the exciton, defect and Eu3+ PL under the inter-band photoexcitation of the ZnO host NCs. The intensity ratio among the three PL peaks is sensitive to the atmosphere for the PL measurements. We discuss the influence of the surrounding gas atmosphere to the PL properties. 相似文献