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91.
Kawahara T. Kawajiri Y. Kitsukawa G. Sagara K. Kawamoto Y. Akiba T. Kato S. Kawase Y. Itoh K. 《Solid-State Circuits, IEEE Journal of》1992,27(4):589-596
A 0.3-μm sub-10-ns ECL 4-Mb BiCMOS DRAM design is described. The results obtained are: (1) a V cc connection limiter with a BiCMOS output circuit is chosen due to ease of design, excellent device reliability and layout area; (2) a mostly CMOS periphery with a specific bipolar use provides better performances at high speed and low power; (3) the direct sensing scheme of a single-stage MOS preamplifier combined with a bipolar main amplifier offers high speed; and (4) the strict control of MOS transistor parameters has been proven to be more important in obtaining high speed DRAMs, based on the 4-Mb design 相似文献
92.
93.
Tatsuo Tabaru Jin-Hak Kim Kazuhisa Shobu Michiru Sakamoto Hisatoshi Hirai Shuji Hanada 《Metallurgical and Materials Transactions A》2005,36(3):617-626
Mo(Si,Al)2-base oxidation-resistant coatings for Nb-base structural materials have been studied. The coating is composed of a Mo(Si,Al)2-base Al reservoir and Al2O3 interlayer to suppress interface reactions between the Al reservoir and the substrate. To develop a suitable Al-reservoir
material, some Mo(Si0.6,Al0.4)2-HfB2 composites were prepared. Their oxidation resistance and coefficients of thermal expansion were investigated, in addition
to their chemical reactivity with the Nb substrate at high temperatures. As a result, Mo(Si0.6,Al0.4)2-20 vol pct HfB2 was selected as one of the satisfactory Al reservoirs. The introduction of a stable Al2O3 interlayer was attempted using a novel powder metallurgical process to overlay the Nb substrates with the Al reservoir, where
the Nb substrates were subjected to a slight surface oxidation prior to the coating process. The Nb specimens, which are thoroughly
coated with the Al reservoir and Al2O3 interlayer, can be successfully fabricated by this method. The coated Nb specimens are not damaged at all after prolonged
exposure in flowing Ar-20 pct O2 at 1673 K for 120 hours. Furthermore, the Al2O3 interlayer is very effective and no reactions occur at the interface. Thus, this Mo(Si,Al)2-base oxidation-resistant coating is applicable to Nb. The utility of the coating system is also confirmed for a NbSS/Nb5Si3 composite.
This article is based on a presentation made in the symposium entitled “Beyond Nickel-Base Superalloys,” which took place
March 14–18, 2004, at the TMS Spring meeting in Charlotte, NC, under the auspices of the SMD-Corrosion and Environmental Effects
Committee, the SMD-High Temperature Alloys Committee, the SMD-Mechanical Behavior of Materials Committee, and the SMD-Refractory
Metals Committee. 相似文献
94.
95.
Tatsuo Akashi 《土木工程与建筑:英文版》2014,(9):1157-1167
The purpose of this paper is to clarify the mechanism of planning failure on land use control in case of sprawl developments of large scale commercial facilities, which is often seen in many countries. The author demonstrates actual three cases in Japan: a huge commercial development established in the middle of rice field between the two local cities, two huge commercial accumulations established at the opposite fringes of urban area, and many large commercial developments established one by one within the small municipalities surrounding a central city. And by examining the statistical sales amount, the author describes that these huge suburban commercial developments apparently deprived the sales of the downtown. Through analyzing these cases, the author empirically stated that for the motorized local cites, the optimum location of commercial accumulation is no longer the central area of the city but about 15 min away from the center with the smooth accessible arterial road. At last, the author mentions that the "planning failure" could be occurred if the territory of planning authority and the scale of the development are inconsistent, such as the authority of small municipal government and the large scale commercial facility which impacts beyond the municipal boundary. 相似文献
96.
Solar thermal applications require some means of thermal energy storage. Amongst several storage concepts, latent heat storage is quite suitable because of its high storage density and almost constant temperature during charging and discharging. The temperature range between 200 and 300°C is considered to be important for solar total energy systems. In this temperature range, sodium nitrate and its mixed salts with other nitrates including eutectic and off-eutectic salts are candidates.
The present paper deals with heat transfer in a latent heat storage unit utilizing these salts. A method of rough estimation of the thermal conductivity of the storage materials is described, and the temperature history of the storage material experimentally obtained is compared with numerical solutions and found to be in reasonably good agreement.
It is seen that the temperature of the heat transfer surface quickly drops soon after the appearance of a solid phase due to low thermal conductivity of these salts. Ways to avoid this temperature drop are discussed. 相似文献
97.
We developed electrostatic system for manipulating small particles with diameters in the range of several micrometers to 100 μm. The electrostatic manipulation probe consists of a monopole pin electrode. When voltage is applied to the electrode, a dielectrophoresis force generated in the nonuniform electrostatic field is applied to the particle near the tip of the electrode. The particle is captured with the application of voltage, and then it is released from the probe by applying a high voltage of the opposite polarity. It is possible to manipulate not only insulative but also weakly conductive particles. A three-dimensional field calculation and a measurement of the adhesion force were conducted to evaluate the force balance for the capture and release of a particle. On the basis of these investigations, we demonstrated the manipulation of actual lunar dust returned by the Apollo 11 lunar surface mission. 相似文献
98.
Masataka Maita Tatsuo Yamanaka Yoshiaki Ohkami Shigeo Kobayashi 《International Journal of Hydrogen Energy》1990,15(12):871-877
For the promotion of extended and diversified space activities in Japan, it is required to build immediately the technology bases capable of supporting such space activities and thereby to expand positively international cooperation as one of Japan's roles towards the world's prosperity of the 21st century. Especially, development of the manned space transportation system to and from lower earth orbit is the key issue, requiring an unprecedented approach. The Single Stage to Orbit(SSTO) Aerospace Plane is the unique answer to this issue. This paper will discuss the perspective on the research and development of the Space Plane in Japan. The topics will cover a long range R&D scenario and current activities of the related organizations in Japan. 相似文献
99.
水相酶促酯化法拆分dl-薄荷醇的连续操作 总被引:1,自引:0,他引:1
对影响脂肪酶活性、稳定性和对映选择性的因素,如有机溶剂和反应温度等首先进行了优化。其次,使用悬浮于环已烷的粉末状游离脂肪酶(CandidacylindracealipaseOF360)作生物催化剂,成功地构建了一个高效的非水相游离酶连续搅拌釜反应器。当使用高度反应性的丙酸酐作为薄荷醇的酰基给体,进行连续的酶促对映选择性酯化反应时,醇的转化率在两周内可保持40%以上,所生成酯的光学纯度超过95%e.e。但是,当使用相应的游离丙酸(而不是酸酐)作酰基给体时,薄荷醇的转化率在连续操作开始后迅速下降,表明使用酸酐时的生产力要比使用游离酸时高。最后,对底物溶液的浓度和流速进行了进一步优化;同时对反应器系统的含水量进行了监测,并通过对酸酐料液的浓度或流速进行微调的方法,有效地将有机溶液相的水分浓度控制在一定的范围(2~4mmol/L)之内,结果,dl-薄荷醇对映选择性连续酯化反应非常稳定地运行了两个月之久(转化率47~35%,光学纯度95~98%e.e.),酶反应器的半衰期超过200天。 相似文献
100.
Sarker PK Takahashi J Kawamoto Y Obayashi Y Kaneko T Kobayashi K 《International journal of molecular sciences》2012,13(1):1006-1017
Aqueous solutions of isovaline and its precursor molecule, 5-ethyl-5-methylhydantoin, were irradiated with ultraviolet and γ-ray photons, to evaluate their structural stability against space radiation. The degree of photolysis was measured and irradiation products were identified using chiral, reversed-phase and ion-exchange high-performance liquid chromatography. The experimental results show that the degree of photolysis of 5-ethyl-5-methylhydantoin is more significant than that of isovaline under ultraviolet light irradiation, while the results under γ-ray irradiation are the opposite. As the products of isovaline photolysis, aspartic acid, serine, glutamic acid and alanine were dominantly detected. 相似文献