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201.
Kozo Tanabe Hideshi Hattori Tsutomu Yamaguchi Susumu Yokoyama Junichi Umematsu Yuzo Sanada 《Fuel》1982,61(4):389-390
The catalytic activity of Fe2O3for the hydrocracking of a bituminous coal at 673K increases when a small amount of SO42? is included in the catalyst. The effect of SO42? is marked in the formation of resins, stronger polar compounds and asphaltenes. 相似文献
202.
Tetsuro Yokono Nobuyoshi Oka Toshiyuki Obara Yuzo Sanada 《Petroleum Science and Technology》1983,1(3):199-204
The stability of distillates derived from the SRC II coal liquefaction process has been investigated by means of electron spin resonance (e.s.r.). The samples were prepared by storing at room temperature for 8 days in air or in vacuo. The lighter fraction of distillate deteriorated more easily via oxidation than the heavier fraction. 相似文献
203.
A thin membrane of bacterial cellulose (BC) obtained from Acetobacter culture was tested for its performance as a dialysis membrane in aqueous systems. The BC membrane showed superior mechanical strength to that of a dialysis-grade regenerated cellulose membrane, allowing the use of a thinner membrane than the latter. As a result, the BC membrane gave higher permeation rates for poly(ethylene glycols) as probe solutes. The cutoff molecular weight of the original BC membrane, significantly greater than that of regenerated cellulose, could be modified by concentrated alkali treatments of the membrane. The nature of the change at the ultrastructural level caused by the alkali treatments was studied by X-ray diffraction and scanning electron microscopy. © 1993 John Wiley & Sons, Inc. 相似文献
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The temperature dependence of the 1H-NMR absorption in coals and pitches have been obtained using a pulsed Fourier transform NMR spectrometer with a high temperature probe. The samples as received were heated in the high temperature probe and NMR spectra were obtained simultaneously. With increasing temperature, the value of the line width at half-height (ΔH1/2) of a brown coal decreases and then increases rapidly. On the other hand, tar pitch and the γ component of a coal indicate that the values of ΔH1/2 remain small over a wide temperature range. It is found that there is an excellent relation between the temperature dependence of ΔH1/2 and the optical texture of the mesophase. 相似文献
208.
Akihisa Kubota Yohsuke Shinbayashi Hidekazu Mimura Yasuhisa Sano Kouji Inagaki Yuzo Mori Kazuto Yamauchi 《Journal of Electronic Materials》2007,36(1):92-97
Elastic emission machining (EEM) is a precise surface preparation technique, which uses chemical reactions between the surfaces
of the workpiece and fine powder particles. The purpose of this study is to clarify the surface removal process of silicon
carbide (SiC) in EEM. A SiC sample with a periodic step-bunched structure was prepared as the initial surface and was flattened
by EEM. Optical interferometer and atomic force microscopy (AFM) observations show that the topmost areas on the periodic
step-bunched structure in contact with the powder particles are preferentially removed and surface protrusion is gradually
reduced as removal depth increases. Moreover, power spectral density analyses reveal that the surface is smoothed in the spatial
wavelength range from 0.07 μm to 10 μm. 相似文献
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Practical studies on rockfall simulation by DDA 总被引:1,自引:0,他引:1
In this paper,simulations of real rockfall by discontinuous deformation analysis (DDA) are conducted.In the simulations,the energy losses of rockfall are categorized into three types,i.e.the loss by friction,the loss by collision,and the loss by vegetation.Modeling of the energy loss using absolute parameters is conducted by the DDA method.Moreover,in order to verify the applicability and validity of the proposed DDA,field tests on rockfall and corresponding simulations of rockfall tests by DDA are performe... 相似文献