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排序方式: 共有497条查询结果,搜索用时 187 毫秒
51.
T Oka T Nakatsu S Kusachi Y Tominaga S Toyonaga K Hori 《Canadian Metallurgical Quarterly》1997,61(8):719-723
A 54-year-old woman was admitted to our hospital because of a heart murmur without subjective symptoms. Angiography disclosed an enlarged right coronary artery and flow drainage into the left ventricle, ie, a large right coronary artery-left ventricle fistula. Analysis of pulsed Doppler studies and cineangiograms indicated considerable capacitance of this fistula owing to Windkessel action, which attenuated volume overload on the left ventricle. The features in this case suggest that evaluation of fistula hemodynamics is important in determining the overload on the ventricle through the fistula. 相似文献
52.
Reactant shape selectivity of supported titanium catalysts for epoxidation of cyclohexene and 2-hexene has an excellent correlation with the pore diameter of the catalysts. With titanosilicate the preference to cis isomer epoxidation is small compared to TiO2-SiO2 probably because of the restriction of its diffusion imposed by the zeolite micropore structure. 相似文献
53.
M Isobe Y Kumura Y Murata S Takaki A Tominaga K Takatsu Z Ogita 《Canadian Metallurgical Quarterly》1992,14(3):755-758
The chromosomal location of the human gene for the alpha subunit of interleukin-5 receptor (IL5RA) has been determined. The human IL5RA gene was localized to the short arm of chromosome 3 by Southern blot analysis of DNA from a panel of mouse-human hybrid somatic cell lines. The IL5RA gene has been further localized to human chromosome region 3p24-3p26 by in situ hybridization of a molecularly cloned IL5RA cDNA fragment to metaphase chromosomes. The results suggest that the IL5RA locus is unlinked to other members of the hematopoietic receptor family. Assignment of the IL5RA gene to chromosome 3 at bands p26-p24 raises the possibility that it may be altered by certain nonrandom chromosomal abnormalities arising in human hematopoietic malignancies and solid tumors. 相似文献
54.
Norio Tokuda Hitoshi Umezawa Sung-Gi Ri Masahiko Ogura Kikuo Yamabe Hideyo Okushi Satoshi Yamasaki 《Diamond and Related Materials》2008,17(7-10):1051-1054
A process of homoepitaxial growth of diamond (111) films by microwave plasma-enhanced chemical vapor deposition has been investigated characterizing areas by ex-situ atomic force microscopy. The evolution of surface morphology during a lateral growth of (111) diamond was visualized utilizing a mesa structure as a marker. Lateral growth forms atomically flat surfaces, which show atomically flat terraces over several hundred nm widths and single bilayer steps of (111) diamond. 相似文献
55.
Studies of proton-conductive polymer membranes are vital for the future development of high-performance polymer electrolyte membrane fuel cells (PEM-FC). In particular, a method for inhibiting the volatility of water in the polymer matrix at high temperatures is a crucial issue, directly related to the operation of PEM-FC system. In this study, we focus on polymer composite membranes, which consist of commercial Nafion and mesoporous silica (MPSi) as novel inorganic additives, and investigate an improvement in the total proton conductivities and the good electrochemical stability at high temperatures. MPSi, which can be synthesized with pore sizes from 1 to 10 nm, has a wide range of potential applications because of its extraordinary properties, such as extremely large surface area, flawless surface condition and well-regulated porous structure. We found that the Nafion composites filled with MPSi have approximately 1.5 times higher proton conductivities (more than 0.1 S cm−1 at 80 °C and 95%RH) than pure Nafion and can display good temperature performance relative to pure Nafion and the particle SiO2 composite. Moreover, the conductivity of Nafion/sulfonated MPSi was the highest (0.094 S cm−1) at 40 °C and 95%RH. These are probably due to the large surface area of MPSi, which can increase the water adsorption in Nafion matrix. 相似文献
56.
57.
Hosoda M. Kawashima K. Tominaga K. Watanabe T. Fujiwara K. 《Quantum Electronics, IEEE Journal of》1995,31(5):954-961
This paper proposes a novel analytical method for use in symmetric self-electrooptic effect device (S-SEED) systems, called the potential function method, based on a global stability analysis of differential equations for photocurrent in S-SEED circuits. The method provides intuitive views for analyzing the stability of the system, and is useful for tracking the temporal dynamics of S-SEED nonlinear electrical circuits. This paper also describes electro-absorption characteristics of SEED's, especially those based on Wannier Stark localization (WSL). In this type of SEED, the photocurrent versus reverse bias voltage characteristics has multiple peaks and multiple negative differential resistance regions, resulting from Stark ladder transitions due to thin barrier superlattices. Various types of stabilities, including the metastable state, as well as the temporal switching dynamics of WSL-S-SEEDs, can be explained clearly by using this potential function method 相似文献
58.
H. Mimura M. Hosoda K. Tominaga T. Watanabe K. Fujiwara 《Solid-state electronics》1996,40(1-8):171-174
We have studied absorption saturation characteristics in short-period GaAs/AlAs superlattice self-electro-optic effect devices based on Wannier-Stark localization. The disappearance of negative differential resistances due to absorption saturation was observed under high optical excitation intensities. To understand the mechanism, we measured the time-resolved photocurrent and time-resolved photoluminescence. Results revealed that the absorption saturation is caused by electric field screening originating from the space-charge of remaining holes due to effective mass filtering. 相似文献
59.
Motoaki Adachi Kikuo Okuyama Seongwon Moon Noboru Tohge Yasuo Kousaka 《Journal of Materials Science》1989,24(6):2275-2280
Ultrafine zirconia particles are produced by thermal decomposition of zirconium tetratertiary butoxide (ZrTB) vapour. The
introduction of ZrTB vapour into the cylindrical electric furnace, is achieved by three different methods: (evaporator, pressurized
nebulizer and ultrasonic nebulizer). The properties of the fine particles obtained by these methods are mainly analysed by
X-ray diffraction and transmission electron microscopy. It is found that ultrafine zirconia particles produced at relatively
low temperatures from 600 to 700° C are spherical in the diameter range 0.035 to 0.15 μm and of tetragonal phase. Furthermore,
two-component fine particles of zirconia-ilver are generated by putting the silver solid inside the furnace containing alkoxide
vapour, and are deposited by inertia on to a glass substrate under low pressure to form films having a thickness of 17 to
33 μm. The electrical characteristics of the films are evaluated, and the conductance of the film is found to increase with
the content of the silver component. 相似文献
60.
During our systematic studies on the arginine vasopressin receptor V1a-antagonistic activity of 1-(1-benzoyl substituted 4-piperidyl)-3,4-dihydro-2(1H)-quinolinones, we found a general substituent effect on the benzene ring. Hydrogen-bonding ability at the ortho position was especially important for enhancement of the affinity of multi-substituted analogs. Details of the syntheses and structure-activity relationships for this series are presented. 相似文献