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排序方式: 共有1581条查询结果,搜索用时 15 毫秒
101.
F.X. Qin X.M. Wang G.Q. Xie K. Wada M. Song K. Furuya K. Asami A. Inoue 《Intermetallics》2009,17(11):945-950
In this study, pure Ti was coated on Zr55Al10Ni5Cu30 bulk metallic glass (BMG) using a physical vapour deposition (PVD) technique with magnetron sputtering. Microstructures of Ti coating, BMG substrate and interface were investigated by conventional and high-resolution transmission electron microscopy (TEM and HREM). The electrochemical behavior of Ti-coated Zr55Al10Ni5Cu30 BMG was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in Hanks' solution. Scanning electron microscopy (SEM) was used to characterize the surface morphology of the coating after electrochemical testing. HRTEM observation reveals that the sputtering Ti coating consists of α-Ti nano-scale particles with the size about 10 nm. The polarization curves revealed that the open-circuit potential shifted to a more positive potential and the passive current density was lower after Ti coating was applied in comparison with that of the monolithic Zr55Al10Ni5Cu30 BMG. Electrochemical impedance spectroscopy (EIS) measurements showed that the Bode plots of Ti-coated Zr55Al10Ni5Cu30 BMG presented one time constant for 1 h and 12 h immersion and two time constants after 24 h immersion. The good bonding condition between Ti coating and Zr55Al10Ni5Cu30 BMG substrate may be responsible for the high corrosion resistance of Ti-coated Zr55Al10Ni5Cu30 BMG. 相似文献
102.
K Wada S Ishizuki T Mori H Bando M Murayama N Kawahara 《Canadian Metallurgical Quarterly》1997,20(9):978-982
Nine alkaloid constituents in the root of Aconitum yesoense var. macroyesoense, as well as three acetylated derivatives, were examined for their peripheral vaso-activities by measuring laser-flowmetrically the cutaneous blood flow in the hind foot of mice after intravenous administration. The major constitutive delcosine (1), 14-acetyldelcosine (2) and lucidusculine (3), respectively, had little or very mild vaso-activity. Kobusine (4) and pseudokobusine (5) and three minor constituents, luciculine (6), 1-acetylluciculine (7) and dehydroluciculine (8), together exhibited a rapid increase in blood flow reaching a peak with a magnitude almost equal to that produced by hydralazine, when administered intravenously at the same dosage level of 20 mg/kg. Among them, 4 was characterized by successive reversal of the increase to a decrease in blood flow, while 7 produced a flow with a more delayed peak time. Dehydrolucidusculine (9) exhibited a transient decrease in blood flow prior to occurrence of the increase, as did papaverine. Consequently, it is assumed that the alkaloids, especially those of the C20-diterpenoid type, in the root of this Aconitum plant have peripherally vaso-dilating activities to varying degrees in mice, probably due to their direct action on the cutaneous microvasculature in a similar fashion to that shown by hydralazine. The laser blood flowmetric method would be useful as an in vivo means of qualitative as well as quantitative screening of chemically modified derivatives of peripherally vasoactive agents in mice. 相似文献
103.
Yamaguchi H. Wada M. Yamamoto H. 《Selected Areas in Communications, IEEE Journal on》1986,4(8):1202-1209
Seeing-while-talking has been a dream of mankind for over a 100 years since the invention of telephone. In the past, various trials were performed in spite of the difficulty in installing the network for the actual service. However, with the progress of ISDN and the advancement of digital signal processing technology, the environment has been changing rapidly. In this paper, an integrated visual communication system is described for the enhanced communication service at 64 kbits/s, the fundamental bit rate of ISDN. The roles of state-of-theart compression of the audio and video signals are discussed and an integrated transmission method based on the priority of the information content is proposed. 相似文献
104.
105.
Yuki Matsushita Junko Taniguchi Ryo Toda Hiroki Ikegami Taku Matsushita Mitsunori Hieda Nobuo Wada 《Journal of Low Temperature Physics》2008,150(3-4):342-346
We have studied heat capacities of 4He adsorbed in straight nanopores 1.8, 2.2, and 2.8 nm in diameter. Heat capacities of the 4He fluid film on the solid layer at 0.08–0.4 K show power laws close to T in 1.8 nm pores, close to T
2 in 2.8 nm pores, and a crossover from T to T
2 with increasing temperature in 2.2 nm pores. These heat capacities are explained by a model assuming a phonon dispersion
with continuous one-dimensional (1D) states in the axial direction and discrete energy levels in the azimuthal direction.
By fitting experimental data to the model, the phonon velocity along the pore axis and the energy gap for propagation in the
cross section are derived. At temperatures sufficiently lower than the energy gap, where the thermal wave length of phonons
is much longer than the effective pore diameter, the 4He fluid films show a T-linear heat capacity of 1D phonons propagating only along the pore axis. At higher temperatures, a 1D-2D crossover of phonons
occurs.
相似文献
106.
107.
T. Nishino T. Watanabe M. Hieda M. Suzuki N. Wada K. Torii 《Journal of Low Temperature Physics》2002,126(1-2):397-402
We measured the mechanical response of
4
He films adsorbed on an oscillating substrate with a small amount of N2 molecules using an ultrasonic technique. Compared with the substrate with no N2 molecules, it was found that nonsuperfluid
4
He films undergo slipping at lower temperature. This means that the frictional force acting on these films is increased by N2 molecules adsorbed on the substrate. 相似文献
108.
E. K. Ohriner T. Wada E. P. Whelan H. Ocken 《Metallurgical and Materials Transactions A》1991,22(5):983-991
The chemistry and microstructure of iron-base alloys resistant to galling wear were determined by using optical microscopy
and scanning electron microscopy (SEM). Castings and weld overlays, deposited by the gas tungsten arc and plasma arc welding
(GTAW and PAW, respectively) processes, were evaluated. The microstructure typically consisted of a primary austenitic matrix,
eutectic carbides (M7C3 type), and noneutectic carbides. Processing techniques that resulted in high cooling rates yielded microstructures with finer
features, less complete partitioning of alloying elements to the carbides, and improved resistance to galling wear. Carbon
and manganese appeared to improve resistance to galling wear. Nickel was detrimental to galling wear resistance.
Formerly with AMAX Materials Research Center
Formerly with AMAX Materials Research Center
Formerly with AMAX Materials Research Center 相似文献
109.
Hirofumi Kakemoto Tohru Higuchi Hajime Shibata Satoshi Wada Takaaki Tsurumi 《Journal of Materials Science: Materials in Electronics》2008,19(4):311-314
The modification of thermoelectric figure of merit was estimated from enhanced mobility of [100] oriented beta-FeSi2 film. beta-FeSi2 on Si(001) substrate was prepared by molecular beam epitaxy method using an Fe source. The crystallographic orientation of
beta-FeSi2 film on Si(001) substrate was characterized by using X-ray diffraction. Using scanning electron microscopy, surface morphology
and film thickness of samples were observed and estimated, respectively. The mobility of beta-FeS2 film on Si(001) substrate were also characterized by Hall measurement at room temperature. A part of the enhancement of figure
of merit was evaluated as the functions of mobility and crystallographic orientation of samples. 相似文献
110.
Namba A. Wada O. Toyota Y. Fukumoto Y. Zhi Liang Wang Koga R. Miyashita T. Watanabe T. 《Electromagnetic Compatibility, IEEE Transactions on》2001,43(4):515-519
This paper presents a simple method to measure the relative permittivity of glass-epoxy printed circuit boards (PCBs). In this method, the relative permittivity as a function of frequency is measured using an actual PCB. In order to estimate the relative permittivity, the reflection coefficient is measured with a network analyzer. The relative permittivity is calculated by observing the frequencies of the resonant cavity modes. We show that the relative permittivity of an FR-4 sample decreases from 4.3 to 4.2 at frequencies from 300 MHz to 2 GHz 相似文献