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71.
Preparation of Morphology‐Controlled Plate‐Like Sodium Niobate Particles by Hydrothermal Synthesis 下载免费PDF全文
Sodium niobate (NaNbO3) particles with plate‐like morphology and hexagonal unit cells were prepared by the hydrothermal method. The result of SEM showed that the hexagonal NaNbO3 were characterized by plate‐like morphology with a diameter of 5–15 μm and a thickness of 1–2 μm. The crucial influences on the morphology and crystal phase of the NaNbO3, such as concentration of [OH?], surfactant, and K+:Na+ ratio, were established. By further calcination treatment, the plate‐like hexagonal NaNbO3 particles could be completely transformed into perovskite structure without morphology change. The XRD and EBSD results indicate that the major face of the calcined particles is parallel to the crystallographic (001)pc (pseudo cubic index) plane. Compared with the traditional high‐temperature molten salt method, this work provides a simpler way to prepare the template for fabricating textured ceramics. 相似文献
72.
Tsukasa Miyagi Shin‐ichi Tanaka Mikimasa Iwata Tadashi Amakawa 《Electrical Engineering in Japan》2015,190(3):30-36
This paper describes experimental and analytic studies on pressure rise and propagation phenomena due to high current arcs in a container with opened pipes. The shape of the experimental container was chosen taking into account underground common ducts. First, arcs were ignited in the container with varying diameter D and length L of the opened pipes and at arc currents of 4 kA to 12.5 kA and an arc duration of 0.1 s. Based on measured waveforms, the maximum pressure rise and the pressure oscillation frequency were obtained. It was found that there is a tendency for to increase with decreasing D and increasing L, and that D has a much greater impact on . In addition, the tendencies of with changing D and L can be approximately explained by Helmholtz resonance. Second, a CFD model for the container with opened pipe was developed based on the experimental results, and simulations were performed. The simulation results were found to correspond to the experimental pressure rise. 相似文献
73.
The minimum void ratio is an index widely used to indicate the contraction characteristics and the densest state of soils. The minimum void ratio obtained by the traditional test method has been utilized to represent the density of soils irrespective of their fines content despite the restriction (FC ≤ 5%). By considering the effect of the blow count, pore water, and their primary properties, the applicability of the minimum void ratio to soils containing fines was examined with an automatic tapping machine. It was confirmed that the blow count of the traditional method is not sufficient for soils with a high fines content. Furthermore, the presence of pore water had a significant effect on the minimum void ratio of soils containing fines. The characteristics of the cyclic minimum void ratio, which indicates the minimum void ratio obtained throughout the repetition of liquefaction and drainage, were also examined. 相似文献
74.
Zhong Xiangyu Hamdani Fethi Xu Jian Shoji Tetsuo Tatsuki Tadashi Morii Jun Sasaki Wakako Ishii Yasunori 《Oxidation of Metals》2019,91(5-6):705-727
Oxidation of Metals - Oxide scale control is one of the critical maintenance issues in fossil fuel power plant. Hence, the water treatment of the feed water has been changed from all-volatile... 相似文献
75.
Takashi Yanagisawa 《Journal of Superconductivity and Novel Magnetism》2016,29(12):3099-3102
Multi-condensate superconductors have multiple excitation modes. Among them, the Nambu-Goldstone mode, Leggett mode, and Higgs mode are important in superconductors. The dispersion relations and mass formulas of these modes in a multi-condensate superconductor are evaluated by using the functional integral method. At low temperatures, the Higgs mode is defined clearly with the action of a quadratic form. The Higgs mass in the BCS model has a non-relativistic correction compared to that of the relativistic Nambu-Jona-Lasinio model. 相似文献
76.
工艺因素对钒锆蓝颜料呈色的影响 总被引:1,自引:0,他引:1
探讨了工艺因素对钒-硅酸锆蓝色颜料合成的影响,用XRD和UV-V光谱对样品进行了表征,得到一些有益的结论。 相似文献
77.
78.
Mr. N. Varahraam Dr. Eng. O. Yanagisawa 《International Journal of Cast Metals Research》2013,26(2):94-102
Equipment for the in-stream treatment of ductile iron has been adapted for gravity-diecasting. The treatment unit consists of a pouring basin, reaction chamber, and a reservoir for holding treated iron. The device is highly mobile in so much that it can be transferred from furnace to successive dies and back again, allowing consecutive pouring. The authors have studied the effect of reaction chamber design and nodularising-alloy type on the microstructure of cast specimens, using three types of chamber design and three types of nodulariser at different temperatures. The results indicate that a carbide-free structure with a high nodule count of up to 1500 n/mm2 within the as-cast structure of a diecast rod specimen of 30 mm dia. can be achieved using this treatment equipment, when employing suitable nodularising alloy and process chamber design. 相似文献
79.
Zhi-xue Tian Akifumi Uozumi Ikutaro Hamada Susumu Yanagisawa Hidetoshi Kizaki Kouji Inagaki Yoshitada Morikawa 《Nanoscale research letters》2013,8(1):203
First-principles calculations were performed to investigate the effect of Pd concentration and oxygen vacancies on the stability of Pd at LaFeO3 surfaces. We found a much stronger tendency of Pd to segregate by taking the aggregation of Pd at LaFe1-xPdxO3-y surfaces into consideration, resulting in a pair of Pd-Pd around a vacancy. Moreover, we predicted that one oxygen-vacancy-containing FeO2-terminated surfaces would be stable at high temperatures by comparing the stability of LaFe1-xPdxO3-y surfaces, which further supports our previous conclusion that a Pd-containing perovskite catalyst should be calcined at 1,073 K or higher temperatures in air to enhance the segregation of Pd in the vicinity of surfaces to rapidly transform the Pd catalyst from oxidized to reduced states on the perovskite support. 相似文献
80.
Fabrication of Low-Porosity Indium Tin Oxide Ceramics in Air from Hydrothermally Prepared Powder 总被引:1,自引:0,他引:1
Chandana P. Udawatte Kazumichi Yanagisawa 《Journal of the American Ceramic Society》2001,84(1):251-253
Compositionally homogeneous indium tin oxide (ITO) ceramics with low porosity were obtained successfully by sintering hydrothermally prepared powders. The fabrication technique began with the preparation of microcrystalline, homogeneously tin-doped (5 wt%) indium oxyhydroxide powder, under hydrothermal conditions. Low-temperature (∼500°C) calcination of the hydrothermally derived powder led to the formation of a substitutional-vacancy-type solid solution of In2 Sn1− x O5− y , and further heating of this phase at temperatures of >1000°C resulted in the formation of the tin-doped indium oxide phase, which had the C -type rare-earth-oxide structure. The sintering of uniformly packed, calcined powder compacts at 1450°C for 3 h in air resulted in low-porosity (∼0.7%) ITO ceramics. 相似文献