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排序方式: 共有160条查询结果,搜索用时 15 毫秒
1.
Mikio Miyake Katsuyuki Takahashi Jun Higashine Masakatsu Nomura 《Fuel Processing Technology》1992,30(3):205-213
A series of mixtures of Japanese subbituminous Taiheiyo coal and Athabasca oil sand bitumen (AOB) with various coal concentrations (0–100 wt%) was coprocessed in a 70 ml autoclave at 420°C for 1 h in the presence of H2 (50 kg/cm2 at room temperature) and sulfided Ni---Mo/Al2O2 catalyst. The mixture containing 2 wt% coal produced the largest amount of hexane soluble fraction (HS) and the smallest amount of benzene insoluble fraction (BI). Thus, a synergistic liquid production occurred for this mixture with 2 wt% coal by suppressing the retrogressive reactions which proceeded for pure AOB. The HS obtained from mixtures with 2–30 wt% showed higher H/C ratios and lower heteroatom contents than those obtained from pure AOB and the mixtures with more than 30 wt% coal. The amounts of transferable hydrogen contained in the mixtures were estimated using anthracene as a hydrogen acceptor. The mixtures with 2–10 wt% coal contained higher amounts of donor hydrogen than pure AOB. The HS yield from the various mixtures was correlated with the amount of donor hydrogens contained in the mixtures, except for the mixture with 10 wt% coal. Thus, the important factor which results in synergism is suggested to be the amount of donor hydrogens contained in the feed mixtures. 相似文献
2.
Hiroyuki Nakahira Masakatsu Maruyama Hideshi Ueda Haruyasu Yamada 《The Journal of VLSI Signal Processing》1993,5(2-3):133-140
This paper describes an image processing system using Image Signal Multiprocessors (ISMPs) adapted to gray-level image preprocessing for image analysis and image enhancement. It is composed of four ISMPs, five 1H-delay-lines, two 512×512×8-bit frame memories, a video timing controller (VTC), two 256-word ×8-bit ×8-table Look Up Tables (LUTs) and 80 nsec/sampling A/D and D/A converters. This multiprocessor system performs convolution operations such as spatial filters, contrast enhancement, and binarization for gray-level images, thinning, thickening, pattern matching etc. for binary images, and image quality improvement for moving images such as T.V. images. Otherwise, it performs feature extraction operations such as area calculations, fillet coordination, and moment calculations for objective image data. Moreover, this system is capable of applying color image processing by using a multiboard system. 相似文献
3.
Hydrogenation of four bituminous coals impregnated with 5 wt% of either mixtures of ZnCl2-MCln (CuCl, CrCl3 and MoCl5) systems or ZnCl2 was carried out using a batch autoclave system at 400° for 3 h at 9.8 MPa of initial hydrogen pressure. The ZnCl2-MoCl5 system showed the highest yield of the hexane-soluble (HS) fraction compared with the other systems irrespective of the coal used. The difference between the yields of HS fractions using the ZnCl2-MoCl5 and other systems was most marked for coals of fairly low volatile matter content, though the conversion was relatively low (47–66%), whilst for coals of high volatile matter content HS yields with the binary melt systems were high (86–91% conversion). Elemental analyses of the HS fractions indicated that the ZnCl2-MoCl5 system is most favourable in decreasing the average molecular weight and the heteroatom content of HS, this characteristic trend being confirmed also with five HS fractions separated by Chromatographic techniques. Both elemental analyses and molecular weights of asphaltene (benzene-soluble materials, BS) indicated that the ZnCl2-MoCl5 system is also most effective in cracking coal structure. 相似文献
4.
The hexane-soluble fractions of hydroliquefied products from three Yallourn brown coal lithotypes have been separated into five fractions by combined silica-alumina packed column chromatography. Analyses of various fractions by g.c.-m.s. permitted the identification of ≈50 components in the saturate fraction and 40 components in the diaromatic fraction, together with 30 components in the monoaromatics. The components identified were quite similar among hexane-soluble portions of all three lithotypes. A marked predominance of even carbon number alkane (C23-C29) was observed in the hydrocarbon fractions from pale lithotype over , and medium light lithotype over both pure ZnCl2 and . However, medium dark lithotype over both melt catalysts produced a saturate fraction with an odd carbon number(C22-C28) preference. Based on spectral methods, Soxhlet extracts obtained from untreated lithotypes (hexane and benzene solubles) were characterized as complex mixtures of higher molecular weight(300–1000) aliphatic hydrocarbons, which were supposed to be a precursor of the saturates produced from the corresponding lithotype in the catalytic hydroliquefaction. 相似文献
5.
Masakatsu Senda 《Sensors and actuators. A, Physical》2010,157(1):19-25
This article reports on output and band characteristics of the two-terminal ultrahigh frequency (UHF) carrier type magnetic field sensor, which is based on impedance change due to magnetic field dependent permeability, and a magnetic field is detected as an amplitude modulation of a UHF carrier voltage. Two types of transmission line configurations (type-A and type-B) are proposed to make a two-terminal sensor rather than the four terminals of the conventional sensor operating on this principle, because the two-terminal sensor is more advantageous in terms of designing and fabricating of the sensor element and the transmission lines than the four-terminal sensor. In the type-A, a half-wave impedance matching line is added between the element and the carrier power supplying points. Also, in the type-B, a carrier power is supplied on the quarter-wave matching line located between the element and the load. The type-A sensor exhibits a lower output and a much narrower 3 dB-bandwidth of a few tens of MHz than the four-terminal sensor. In contrast, a higher output than that in the four-terminal sensor and a 3 dB-bandwidth of ~100 MHz are confirmed in the type-B sensor by experiments and calculations. 相似文献
6.
Effect of running‐in process on friction behaviour of carbon nitride (CNx) coating in N2 gas stream was investigated with a newly introduced two‐step ball‐on‐disk friction test, where the rubbed Si3N4 ball in the pre‐sliding (step 1) was replaced by a new CNx‐coated Si3N4 ball in the subsequent sliding stage under N2 gas (step 2). The two‐step friction test is clarified to be a simple but effective technique for obtaining contact material combination of self‐mated CNx coatings and for achieving stable and low frictions of CNx coatings. Friction coefficients of CNx/CNx in N2 gas stream decrease greatly from 0.07 without pre‐sliding to less than 0.025 in two‐step friction tests. The minimum friction coefficient of 0.004 was obtained by introducing 500 cycles of pre‐sliding in ambient air. These stable and low frictions are attributed to the generation of self‐mated CNx coatings and the formation of a lubricious layer on the disk surface. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
7.
Masakatsu Saeki 《Journal of Nuclear Materials》1981,99(1):100-106
The release behavior of tritium formed in graphite has been investigated as a function of radiation damage by means of isochronal annealing of samples heavily irradiated by neutrons. The lithium impurities in graphite were estimated as the source of tritium formation. The main chemical form of released tritium was hydrogen accompanied by a small quantity of methane. No other hydrocarbons could be detected. Tritiated water was always measured, but the formation mechanism was experimentally confirmed as the secondary oxidation of released HT molecule. The release spectrum of tritium in isochronal annealing was shifted to a higher heating temperature with the increase of the neutron fluence received by the graphite crystal. A relationship was established between the amount of tritium released up to a certain temperature and the degree of graphitization of the sample. 相似文献
8.
Yugo Tadano Shota Urushibata Kazuya Ogura Akira Shigaki Masakatsu Nomura 《Electrical Engineering in Japan》2008,165(2):77-88
Recently, high‐voltage motor direct drive systems have been put to practical use, and various multilevel PWM strategies have also been proposed. This paper describes a multilevel PWM strategy [our group calls it the Carrier Phase Selection Method (CPS)] that has the lowest line voltage harmonic distortion in order to prevent the degradation of high‐voltage motor winding insulations. This method takes the adverse effect of dead time into consideration, and it controls the shift direction of a carrier phase. Therefore, a favorable output waveform without instantaneous voltage surges is achieved even if the line voltage level changes. Moreover, the switching transitions across all switching devices are well‐balanced, so the utilization of inverter unit cells is equalized. This is an important factor when designing the entire system. Based on simulation and experimental results, it is shown that this CPS method is particularly effective in high‐voltage motor direct drive systems. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(2): 77–88, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20474 相似文献
9.
Twelve kinds of cation-exchange membranes were treated with hydrogen peroxide. Some of them (Selemion CMV, Nepton CR-61, Scrion C-100, SAM-1) were completely destroyed. Heterogeneity is believed to be present in that part of their chemical structures that is decomposable by the treatment. The other membranes were converted into porous membranes by the decomposition of the resinous part. Water permeabilities and electric resistances of the porous membranes were examined to evaluate the pore radius. It was concluded that the “paste method” membranes have a heterogeneity or localized distribution of the resinous part under 50 mμ. The “paste method” membranes seemed to resemble the “graft method” membranes in chemical structure and to be much different from the mosaic-type membranes such as Permaplex and MC-3142. These results were also supported by extraction of the membranes with appropriate solvents and observation by electron microscopy. 相似文献
10.
Mercury and selenium concentrations in the internal organs of toothed whales and dolphins marketed for human consumption in Japan 总被引:3,自引:0,他引:3
Small cetaceans (toothed whales odontoceti and dolphins delphinidae) have been traditionally hunted along the coast of Japan and fresh red meat and blubber, as well as boiled internal organs such as liver, kidney, lung and small intestine, are still being sold for human consumption. We surveyed mercury contamination in boiled liver, kidney and lung products marketed in Japan between 1999-2001. The average +/- S.D. of total mercury (T-Hg) was 370 +/- 525 (range: 7.60 approximately 1980, n = 26) microg/g in liver, 40.5 +/- 48.5 (7.30-95.1, n = 15) microg/g in kidney and 42.8 +/- 43.8 (2.10-79.6, n = 23) microg/g in lung. A high correlation was observed between T-Hg and selenium (Se) concentrations in these organs, supporting the formation of a Hg-Se complex. The formation of a Hg-Se complex probably contribute to the detoxification of Hg for cetaceans and allows a very large accumulation of Hg in livers. The provisional permitted level of T-Hg in marine foods set by the Japanese Ministry of Health and Welfare is 0.4 microg/ g, and the provisional permitted weekly intake (PTWI) set by WHO is 5 microg/kg bw/week. The maximal T-Hg detected in boiled liver (1,980 microg/g) exceeds the permitted level by approximately 5,000 times and the consumption of only 0.15 g of liver exceeds the PTWI of 60 kg of body weight of the consumer, suggesting the possibility of an acute intoxication by T-Hg even after a single consumption of the product. 相似文献