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排序方式: 共有1207条查询结果,搜索用时 31 毫秒
61.
Hiromichi Gima Jun Adachi Masahito Katayama Hiroaki Muta Masayoshi Uno Shinsuke Yamanaka 《Journal of Nuclear Materials》2009,389(1):155-159
We prepared polycrystalline pellets of (U,Y)O2, containing YO1.5 up to 11 mol.%. We performed indentation tests on the pellets, and evaluated the Young’s modulus and hardness. We measured the heat capacity and the thermal diffusivity, and evaluated the thermal conductivity. We succeeded in evaluating the effect of Y content on the thermophysical properties of (U,Y)O2. We revealed that the Young’s modulus, hardness, and thermal conductivity of (U,Y)O2 decreased with increasing the Y content. 相似文献
62.
63.
Ralph Skomski Priyanka Manchanda Ichiro Takeuchi Jun Cui 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(7):1144-1150
The geometrical optimization of aligned hard-soft permanent-magnet nanocomposites is investigated by model calculations. Considered criteria are the shapes of the soft and c-axis-aligned hard phases, the packing fraction of the soft phase, and magnetostatic interactions. Taking into account that the energy product is enhanced via the volume fraction of the soft phase, subject to maintaining coercivity, we find that the best structures are soft-magnetic cubes as well as long rods with a square cross section. Comparing embedded soft cubes with embedded soft spheres of the same size, our nucleation-field analysis shows that the volume fraction of the soft phase is enhanced by 91%, with a coercivity reduction of only 25%. Magnetostatic interactions often but not always deteriorate the permanent-magnet performance, as exemplified by the example of MnBi:FeCo bilayers and multilayers. 相似文献
64.
We have measured spectra of the light emission from the frictional contact between the pin of natural diamond, synthetic fused silica, MgO, or NaCl and the disk of quartz or synthetic sapphire in a vacuum in the wavelength range between 380 and 1000 nm. Each spectrum shows the relaxation of electronic excited vacancies, which are thought to be produced at the solid surface by mechanical abrasion. 相似文献
65.
The H infin loop-shaping method is known to be an effective control method. However, it has two drawbacks. The first is that it is difficult to select appropriate loop-shaping weights, and the second is that the resulting controller is very complex. For the first drawback, Lanzon has proposed a suboptimal loop-shaping weight design method. It is formulated as a generalized eigenvalue minimization problem (GEVP). This suboptimal loop-shaping weight design method provides high-order weights, exacerbating the second drawback. To resolve these two drawbacks, a reduced-order loop-shaping weight design method is proposed for SISO systems in this paper. In the proposed method, the weight structure is first fixed, and the weight is then decomposed into a frequency-dependent vector and parameter matrices characterizing the loop-shaping weight. Since the open-loop constraints are represented as linear matrix inequalities with respect to the parameter matrices, the proposed reduced-order loop-shaping weight design problem for SISO systems is formulated as a GEVP, as well as Lanzon's suboptimal loop-shaping weight design method. The proposed method can reduce the designer's burden, although it is only valid for SISO systems. The effectiveness of the proposed method is verified experimentally by velocity control of a belt-driven two-mass system. 相似文献
66.
Jiping Li Gang Tong Dianbo Shi Meng Geng Huawei Zhu Ichiro Hagiwara 《Engineering with Computers》2009,25(3):279-285
The recognition and suppression of small features from B-rep models play an important role in effectively generating the qualified
mesh for analysis. This paper presents a new algorithm for recognizing small blends automatically for the purpose of mesh
generation. The algorithm first transforms the input B-rep model into an aggregation of faces. Then, each face is judged to
be a blend or not based on matching conditions. At last, the blends with larger physical sizes than a threshold value are
excluded. The innovations lie in the recognition conditions and the unique calculating procedure of the blend physical size.
Several examples are given to demonstrate the validity and applicability of the algorithm. 相似文献
67.
Based on literature sources and the author's own research, this article presents the current state of knowledge about composite coatings created by means of the plasma transfer method. The general characteristics of composite coatings and their strengthening mechanisms have been described. Methods of creating composite coatings by means of the plasma transfer method have also been discussed. 相似文献
68.
69.
Kei Masaki Yusuke K. Shibama Shinji Sakurai Masahiro Katayama Akira Sakasai 《Fusion Engineering and Design》2011,86(9-11):1872-1876
JT-60 is planned to be upgraded to JT-60SA tokamak machine with fully superconducting coils, which is a project of the JA-EU satellite tokamak program under both Broader Approach program and Japanese domestic program. The JT-60SA vacuum vessel (VV) has a D-shape poloidal cross section and a toroidal configuration with 10° facet segmented in toroidal direction. The material of the VV is 316L stainless steel with low cobalt content of <0.05 wt%. A double wall structure is adopted for the VV to ensure high rigidity and high toroidal one-turn resistance simultaneously.Fundamental welding R&D and a trial manufacturing of the 20° upper half of the VV have been performed to study the manufacturing procedure. After the confirmation of the quality of the mock-up, manufacturing of the actual VV started in November 2009. 相似文献
70.
Koji Nishimoto Yoshihiro Okumoto Tomoki Harano Ken Atagi Hiroo Fujii Seiji Katayama 《Welding International》2013,27(11):824-829
Laser pressure welding was conducted by changing the laser power and the roller pressure in the previous experiment. It was revealed that dissimilar metal welding of galvannealed steel and pure aluminium was feasible in a wide range of welding conditions. When the roller pressure was more than 1.96 kN at the laser powers equal to or less than 1400 W, the joint strengths were so high that the specimens in the tensile shear and the peel tests fractured in the A1050 parent metal. In order to know the reason for such high strengths of joints with thick compound layers and the joining mechanism, the compound layer was observed by HR-transmission electron microscopy (TEM). The TEM observation results revealed that the main phase in the compound layer was the solid solution of Al + Zn. Moreover, the intermetallic compound was identified as FeAl, Fe2Al5, Fe4Al13 and Fe2Al5Zn0.4 phase by electron diffraction. The Fe3Zn10 (Γ phase) of Fe–Zn intermetallic compound was confirmed on a Fe base material. It is guessed that the joining areas were heated at a range of 782°C more than 665°C, a melting point of Al, by laser irradiation because the δlk phase aspect was not confirmed. Because the surfaces of A1050 and Zn plated layer were melted thinly, the layer was over 10 μm thicker. The reason for the production of high-strength joints with a relatively thick intermetallic compound layer was attributed to the formation of (Al + Zn) phase with finely dispersed intermetallic compounds. 相似文献