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排序方式: 共有292条查询结果,搜索用时 46 毫秒
51.
Phase equilibria of Sn-In based micro-soldering alloys 总被引:1,自引:0,他引:1
I. Ohnuma Y. Cui X. J. Liu Y. Inohana S. Ishihara H. Ohtani R. Kainuma K. Ishida 《Journal of Electronic Materials》2000,29(10):1113-1121
The phase equilibria of Sn-In-X (X=Ag, Bi, Sb, Zn), the most basic information necessary for the development of Pb-free micro-soldering
alloys, were studied using the CALPHAD method. Thermodynamic analyses for describing the Gibbs energies of the constituent phases were made by optimizing the obtained
data on the experimental phase diagrams, and such data in the literature, including data on thermochemical properties. The
present results combined with the thermodynamic database which was recently developed by our group [I. Ohnuma et al., J. Electron. Mater. 28, 1164 (1999)] provide various information on phase equilibria such as liquidus and solidus surfaces, isothermal and vertical
section diagrams, mole fractions of the phase constitutions, etc., and thermodynamic properties such as activity, heat of
mixing, surface energy, viscosity, etc., in multi-component soldering alloy systems including the elements of Pb, Bi, Sn,
Sb, Cu, Ag, Zn, and In. Typical examples for the phase diagrams and thermodynamic properties of Sn-In-X ternary systems are
shown. The application of the database to the alloy design for Pb-free solders is also presented. 相似文献
52.
Synthesis of binary copper chalcogenides by mechanical alloying 总被引:2,自引:0,他引:2
Copper sulfides (tetragonal Cu1.92S-Cu1.99S, rhombohedral Cu1.71S-Cu1.89S, CuS), selenides (β Cu2 − xSe, Cu3Se2, γ CuSe, CuSe2), and tellurides (Cu2 − xTe, Cu3Te2) were prepared from mixtures of the elements by mechanical alloying (MA), using a high-energy ball mill. The compounds were obtained by 60–120 min of MA. It is notable that two metastable high-pressure phases were obtained by MA: tetragonal Cu2 − xS and pyrite-type CuSe2. The tetragonal phase gradually transformed to the stable phase of djurleite when kept at room temperature. Cu1.71S-Cu1.89S also formed a metastable rhombohedral phase. 相似文献
53.
A novel bacterial rhodopsin was identified in Haloarcula japonica strain TR-1. The gene encoding the bacterial rhodopsin was cloned and sequenced. The structural gene consisted of an open reading frame of 750 nucleotides encoding 250 amino acids. The deduced amino acid sequence of the Ha. japonica bacterial rhodopsin showed the highest homology to those of cruxrhodopsins. 相似文献
54.
J Yamamoto Y Shimamura H Nakahara Y Koishi M Kougo H Ohtani H Watanabe M Ishii M Ohmura 《Canadian Metallurgical Quarterly》1997,132(7):785-788
The leakage of pancreatic juice is the most serious complication after pancreatoduodenectomy. In an attempt to lessen the incidence of this complication, we have developed a simple technique for the anastomosis of pancreatogastrostomy. Since March 14, 1995, we have already performed surgical procedures on 8 cases of pancreatogastrostomy using this technique and as yet have never experienced fatal complications. We report the autopsy findings of pancreatogastric anastomosis histologically. The specimen taken from the anastomosis reveals good mucosal continuity. This result suggests the importance of reliable sutures between the pancreatic parenchyma and the full thickness of the gastric wall for the anastomosis of pancreatogastrostomy. 相似文献
55.
Huzo Kato Kohichi Ohtani Takehru Kohri Masahiro Morikura Masahiro Umehira Shuji Kubota 《International Journal of Satellite Communications and Networking》1988,6(3):289-300
Devices and architectures for on-board SCPC (single channel per carrier) multi-carrier demodulators suitable for use in satellites to be launched between the present and the year 2000 are discussed in the light of trends in the development of device technology towards lower on-board weight and power consumption. It is shown that at the present time (equivalent to about 1990 for on-board use). The choice of demodulation scheme depends on the number of channels available for regeneration on board the satellite. The total weight and power consumption for several suitable on-board multicarrier demodulation schemes are predicted for 1990, 1995 and 2000, as functions of the number of channels to be regenerated. 相似文献
56.
T Hosoki M Mitomo S Chor N Miyahara M Ohtani K Morimoto 《Canadian Metallurgical Quarterly》1997,38(3):422-427
PURPOSE: To assess the visualization of tumor vessels in hepatocellular carcinoma (HCC) by power Doppler sonography. MATERIAL AND METHODS: We examined 40 patients with 47 HCC lesions by means of power Doppler sonography and compared its visualization of tumor vessels with those of color Doppler and angiography. RESULTS: In 38 (81%) of the 47 lesions, power Doppler sonography improved the visualization of tumor vessels compared with color Doppler sonography; in the remaining lesions no significant difference was noted. In lesions located within 7 cm in depth, there was no significant difference between power Doppler sonography and angiography. In 10 (83%) out of 12 small (< or = 2 cm in diameter) lesions and in 11 (85%) out of 13 hypovascular lesions, power Doppler sonography performed considerably better than angiography. In deeper-seated lesions, however, angiography was significantly superior to power Doppler sonography. CONCLUSION: Power Doppler sonography is more sensitive in detecting the fine tumor vessels in most HCCs than color Doppler sonography. In addition, power Doppler sonography can replace angiography in evaluating tumor vascularity in HCCs except in lesions that are deep-seated or located near the heart. In these lesions, angiography can complement power Doppler sonography in demonstrating tumor vessels. 相似文献
57.
58.
Friction opposes tooth motion whenever sliding mechanics is employed. Understanding what friction is and how to manage it is of paramount importance to the successful practitioner. In this article, the coefficients of friction are summarized between different arch wire-bracket couples as a function of material, geometric, and external parameters. From this vantage point, friction can then be evaluated within the context of other factors that affect sliding-binding and notching. 相似文献
59.
Yingxi Zhu Hiroko Ohtani Michael L. Greenfield Marina Ruths Steve Granick 《Tribology Letters》2003,15(2):127-134
The molecular-level function of model and commercial friction modifier additives in lubricants of the type used at the wet clutch interface in automatic transmissions has been studied using a surface forces apparatus (SFA) modified for oscillatory shear. The nanorheological properties of tetradecane with and without a model friction modifier additive (1-hexadecylamine) were examined in the boundary lubrication regime and compared to a fully-formulated automatic transmission fluid (ATF). 1-Hexadecylamine adsorbed as a single layer on the sliding surfaces, reduced the static frictional force and the limiting shear stress, and eliminated the stick–slip transition that exists in pure tetradecane. The ATF, which contains commercial-grade friction modifiers, showed nanorheological properties similar to those observed for tetradecane containing 0.1–0.2 wt% 1-hexadecylamine. 相似文献
60.
Tatsuya Tokunaga Hiroshi Ohtani Mitsuhiro Hasebe 《Journal of Phase Equilibria and Diffusion》2006,27(1):83-91
The glass-forming ability of Ti−Be alloys is of great interest. Experimental and theoretical evaluations of the glass-forming
ability of this binary alloy show that the formation of a metastable TiBe phase with a CsCl-type B2 structure controls the
glass-forming ability in this system. However, there is no information on the thermochemical properties of metastable TiBe
for the quantitative evaluation of the glass-forming ability using Davies-Uhlmann kinetic formulations. We have carried out
a thermodynamic analysis using experimental phase diagram data and the energy of formation of the stoichiometric compounds
from ab initio calculations. Furthermore, the Gibbs energy of formation for the body-centered cubic (bcc) phase was evaluated
over the entire composition range by applying the cluster expansion method (CEM) to the total energy of some bcc-based ordered
structures obtained from ab initio calculations. For the bcc phase, the two-sublattice formalism, (Ti, Be)0.5(Ti,Be)0.5, was adopted to describe the A2/B2 transformation. A good agreement between the calculated values and experimental phase
equilibria was obtained. Evaluation of the glass-forming ability was also attempted utilizing the thermodynamic quantities
obtained from the phase diagram assessment. The calculated glass-forming ability agrees well with the experimental results.
This paper was presented at the International Symposium on User Aspects of Phase Diagrams, Materials Solutions Conference
and Exposition. Columbus, Ohio, 18–20 October, 2004. 相似文献