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排序方式: 共有970条查询结果,搜索用时 31 毫秒
1.
Toshihiko Kujime Soong-Keun Hyun Hideo Nakajima 《Metallurgical and Materials Transactions A》2006,37(2):393-398
A lotus-type porous carbon steel with cylindrical pores was fabricated by the continuous zone melting method in a pressurized
mixture of hydrogen and helium gases. The porosity increases with increasing partial pressure of the hydrogen gas, while the
pore diameter remains almost constant, independent of the pressure. The ultimate tensile strength of the specimen with cylindrical
pores parallel to the tensile direction is lower than the estimated value, assuming that the strength is decreased in proportion
to the decrease of the cross-sectional area of the specimen, while the yield strength is higher than the estimated value.
The compressive yield strength is also higher than the estimated value. The increase in yield strength is considered to be
due to precipitation strengthening. The tensile strength is increased by quenching and tempering, while the elongation decreases.
Such mechanical properties are discussed in terms of the microstructural analysis. 相似文献
2.
Kenji Tsutsui Takami Tohyama Sadamichi Maekawa 《Journal of Low Temperature Physics》2003,131(3-4):257-261
We examine theoretically the phonon dynamics in the electron-phonon-coupled systems. The model Hamiltonian is a one-dimensional Hubbard model where the hopping of electrons induces the electron-phonon coupling. The numerically exact diagonalization of the Hamiltonian with truncation of the total number of phonons is performed. We calculate the phonon excitation spectra and find that the softening of phonons occurs in insulating case, and a diffusive character appears in the metallic case. We also calculate the charge and spin excitation spectra and find that the dynamics of the phonon coupled with the hopping of electrons is affected by the low energy charge and spin excitations. 相似文献
3.
Toshihiko Hoshide Junpei Fujita 《Journal of Materials Engineering and Performance》2008,17(5):627-632
Strength of ground ceramics may be affected by residual stress as well as surface flaws induced by grinding. Strength prediction
for ground ceramics is convenient for mechanical design of ceramic components. In this article, a numerical procedure based
on fracture mechanics was proposed to estimate strength distribution of ground ceramics by considering grinding-induced residual
stress. Bending strength and residual stress of ground ceramics were measured for three grinding-conditions. By comparison
of simulated results with experimental ones, it was revealed that strength characteristics in experiments were well simulated
by using the proposed procedure. 相似文献
4.
In this article, we consider a flexible beam with a rigid body, of which the bending vibration and the torsional vibration are decoupled. Therefore we need two control motors to suppress the vibrations. Each set of dynamic equations is treated in the form of an appropriate Hilbert space. A stabilizing feedback control law of each rotation motor will be established on the basis of modal analysis. A set of experiments has been carried out, and the results demonstrate the effectiveness of the dynamic model and the proposed control law. © 1994 John Wiley & Sons, Inc. 相似文献
5.
Yoshiyuki Uno Akira Okada Kensuke Uemura Purwadi Raharjo Toshihiko Furukawa Kosaku Karato 《Precision Engineering》2005,29(4):171-455
A new finishing process for metal molds by large-area electron beam (EB) irradiation is proposed in this study. In the large-area EB irradiation equipment used here, an EB with high-energy density is irradiated without focusing the beam, and so the EB with a maximum diameter of 60 mm can be used for melting or evaporating metal surface instantly. Experimental results show that the surface roughness decreases from 6 μmRz to less than 1 μmRz in just a few minutes under proper machining conditions. The corrosion resistance of metal mold surface also could be greatly improved by large-area EB irradiation. Furthermore, the surface roughness of tilting surface close to 90° could be well improved. Therefore, large-area EB irradiation method has a possibility to become a high-efficiency finishing process for metal molds. 相似文献
6.
K Maekawa H Ohnishi T Hirase T Yamada T Matsuo 《Canadian Metallurgical Quarterly》1994,235(5):489-492
A 33-year-old pregnant woman suffered from acute anteroseptal myocardial infarction at the 19th gestational week. Despite periodic attacks of myocardial ischaemia after admission, the coronary arteriograms under the use of nitroglycerin were normal. Thereafter, she remained free from the ischaemic events with diltiazem hydrochloride and delivered a healthy baby. The coronary arteriography at puerperium also showed no organic narrowing. However, the provocative test with acetylcholine chloride caused severe spasm of the left anterior descending coronary artery. These findings strongly suggest that acute myocardial infarction in this pregnant woman was caused by coronary artery spasm. 相似文献
7.
The three-dimensional dynamics of two interacting quantized vortex filaments is studied. The equations of motion and the method of numerical calculation follow Schwarz. Whether two approaching filaments reconnect or not depends on their arrangement before approach. When a ring moves toward a line from a distance, only within a critical initial distance they can reconnect. The critical distance is minimized when their circulations are parallel at the closest place, while it increases as their circulations begin to deviate from being parallel. Hence the reconnection probability can be less than unity. 相似文献
8.
Tohru Morii Hiroyuki Hamada Muriel Desaeger Akihiko Gotoh Atsushi Yokoyama Ignaas Verpoest Zen-ichiro Maekawa 《Composite Structures》1995,32(1-4):133-139
This study deals with the impact property and damage tolerance of matrix hybrid composite laminates with different laminate constitution. The matrix hybrid composite laminates consisted of the laminae with a conventional epoxy resin and the laminae with a flexible epoxy resin modified from the conventional resin to avoid the interlaminar delamination. The impact energy absorption ratio greatly depended on the matrix resin placed at the impact face. The energy absorption was almost constant if the conventional resin was placed at the impact surface layer, while it increased exponentially with the increasing fraction of the flexible resin if the flexible resin was placed at the impact face. The impact energy was absorbed by the damage development and propagation in the laminate with conventional resin laminae as the impacted face, while it was absorbed by both the recoverable deformation of the flexible resin and the damage propagation in the laminate with flexible resin laminae as the impacted face. 相似文献
9.
Hideo Sawada Sachiko HataNobuhito Kawasaki Jun-ichi IidzukaKentaro Tokugi Jun KyokaneTomomi Maekawa Tokuzo Kawase 《Polymer》2002,43(3):1035-1038
New fluoroalkyl end-capped fullerene cooligomers were prepared by the reactions of fluoroalkanoyl peroxides with fullerene and comonomers such as acryloylmorpholine, N,N-dimethylacrylamide and acrylic acid. These fluorinated fullerene cooligomers were easily soluble in water and common organic solvents, and were able to reduce the surface tensions of both water and benzene, quite effectively. Additionally, these fullerene cooligomers were found to form a stable monomolecular film at the air-water interface, and the modified polystyrene surface treated with these cooligomers was shown to have a strong hydrophilicity with good oil repellency. 相似文献
10.
Hiroaki Yamada Toshihiko Tanaka Shigeyuki Funabiki 《Electrical Engineering in Japan》2006,157(4):56-65
This paper proposes a novel method of suppressing the inrush current of transformers. A small‐rated voltage‐source PWM converter is connected in series to the transformers through a matching transformer. As the connected PWM converter serves as a resistor for the source current, no inrush phenomena occurs. The required rating of the PWM converter, which serves as the damping resistor for the inrush phenomena, is 1/400 that of the main transformers in single‐phase circuits. In three‐phase circuits, it is 1/900. The basic principle of the proposed method is discussed. Digital computer simulation is implemented to confirm the validity and excellent practicability of the proposed method using the PSCAD/EMTDC. A prototype experimental model is constructed and tested. The experimental results demonstrate that the proposed method can perfectly suppress the inrush phenomena. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 56–65, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20174 相似文献