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91.
Koji Mori Masuo Kaji Kotohiko Sekoguchi Manabu Sakane Masao Nakazatomi Hideo Shimizu 《亚洲传热研究》1996,25(8):499-510
Time-series information on both the cross-sectional mean liquid holdup along a tube axis and the gas-liquid phase distribution along a tube diameter was obtained by means of supermultiple cross-sectional mean liquid holdup probes (S-CHOP) and semi-supermultiple point-electrode probes (SS-PEP) for vertical downward gas-liquid two-phase flow. Typical time-spatial behavior charts of interface and gas-liquid interfacial profiles are presented. Close inspection of these results reveals that a huge wave and a disturbance wave appear in downward two-phase flow as well as upward flow. It was clarified that the huge wave flow region covers a wide range of superficial gas velocities. Wave velocity, wave width and maximum liquid holdup of individual waves were examined by wave-vein analysis. Histograms of these flow parameters were also studied. It was found that there exist distinct differences in wave width between the huge wave and the disturbance wave. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(8): 499–510, 1996 相似文献
92.
A warpage index (Δψm) was introduced for studying warpage characteristics of a plastic part injection molded from PA66 compounded with 30 wt% glass fiber. Δψm is defined as Δψm = (Δψm)max – (Δψm)min, where ψm = ψ(θ)max, where ψ(θ) = (ε(θ) – α(θ)ΔT)/| α(θ)ΔT|, where ε is the total strain, α is the linear thermal expansion coefficient, ΔT is temperature difference, and θ is the angle along which ε and α are calculated. Finite element analysis was used for calculating flow field in injection, fiber orientation, material anisotropy and warpage. ψm is calculated in each finite element, and Δψm is calculated in a whole finite element model. Δψm is a measure of the ratio of actual shrinkage to the amount of shrinkage that would occur if an element freely shrank. The characteristics of Δψm were studied. It has been found that warpage is null if Δψm = 0, but that null warpage generally does not indicate Δψm = 0. It is shown that Δψm quantitatively represents the warped and unwarped state. Δψm distinguishes the null warpage state with possible buckling from the null warpage state without possible buckling. It has been shown that material anisotropy is possibly described with Δψm, and that the cause of warpage is self-restrictive deformation in an injection molded part. It has been deduced that it is generally not possible to eliminate warpage only by controlling material properties. Δψm is obtainable for a plastic part with complex geometry and complex fiber orientation state, and for arbitrary materials. Applications of Δψm are left for future study. 相似文献
93.
94.
Mitsunobu Kawano Toshiaki Matsui Ryuji Kikuchi Hiroyuki Yoshida Toru Inagaki Koichi Eguchi 《Journal of power sources》2008
Direct internal and external reforming operations on Ni-samaria-doped ceria (SDC) anode with the practical size solid oxide fuel cell (SOFC) at intermediate temperatures from 600 to 750 °C are carried out to reveal the reforming activities and the electrochemical activities, being compared with the hydrogen-fueled power generation. The cell performance with direct internal and external steam reforming of methane and their limiting current densities were almost the same irrespective of the progress of reaction in the methane reformate at 700 and 750 °C. The durability test for 5.5 h at 750 °C with direct internal reforming operation confirmed that the cell performance did not deteriorate. The operation temperature of the cell controlled the reforming activities on the anode, and the large size electrode gave rise to high conversion due to the slow space velocity of the steam reforming. Direct internal steam reforming attained sufficient level of conversion for SOFC power generation with methane at 700 and 750 °C on the large Ni-SDC cermet anode. 相似文献
95.
Cheol Ho Pyeon Masao Yamanaka Akito Oizumi Masahiro Fukushima Go Chiba Kenichi Watanabe 《Journal of Nuclear Science and Technology》2019,56(8):684-689
This study demonstrates, for the first time, the principle of nuclear transmutation of minor actinide (MA) by the accelerator-driven system (ADS) through the injection of high-energy neutrons into the subcritical core at the Kyoto University Critical Assembly. The main objective of the experiments is to confirm fission reactions of neptunium-237 (237Np) and americium-241 (241Am), and capture reactions of 237Np. Subcritical irradiation of 237Np and 241Am foils is conducted in a hard spectrum core with the use of the back-to-back fission chamber that obtains simultaneously two signals from specially installed test (237Np or 241Am) and reference (uranium-235) foils. The first nuclear transmutation of 237Np and 241Am by ADS soundly implemented by combining the subcritical core and the 100 MeV proton accelerator, and the use of a lead-bismuth target, is conclusively demonstrated through the experimental results of fission and capture reaction events. 相似文献
96.
The ion-selective property of hydrous ferric oxide precipitate films has been investigated by measuring membrane potentials which arise across precipitate membranes of hydrous ferric oxide with and without adsorbed MoO42? ions and of ferric molybdate in solutions of NaCl, KCl, MgCl2, CaCl2, BaCl2, AlCl3, and FeCl3. The hydrous ferric oxide membrane was only permeable to Cl? ions in chloride solutions, whereas the membrane with adsorbed MoO42? ions was permeable to cations in NaCl and KCl solutions, and to both Cl? and cations in the presence of multivalent cations. The ferric molybdate membrane was permeable to Cl? and cations in NaCl and KCl solutions, and only to Cl? ions in the presence of multivalent cations. It is suggested that in chloride solutions, the corrosion of iron covered with a precipitate film of hydrous ferric oxide is accelerated by enrichment of Cl? ions under the film, which may decrease the local pH and introduce a positive diffusion potential in the film. The adsorption of MoO42? ions on the oxide changes the ion-selectivity of the precipitate film from the anion-selective to the cation-selective in solutions of NaCl and KCl. This cation-selectivity of the film may inhibit the corrosion of iron, because of H+ ions diffusing out of the film. The inhibitive effect of MoO42? ions would be reduced in the presence of multivalent cations. 相似文献
97.
Huiyuan Geng Takahiro Ochi Shogo Suzuki Masaaki Kikuchi Satoru Ito Junqing Guo 《Journal of Electronic Materials》2013,42(7):1999-2005
Bulk multifilled n- and p-type skutterudites with La as the main filler were fabricated using the spark plasma sintering (SPS) method. The thermoelectric properties and thermal stability of these skutterudites were investigated. It was found that the interactions among the filling atoms also play a vital role in reducing the lattice thermal conductivity of the multifilled skutterudites. ZT = 0.76 for p-type La0.8Ba0.01Ga0.1Ti0.1Fe3CoSb12 and ZT = 1.0 for n-type La0.3Ca0.1Al0.1Ga0.1In0.2Co3.75Fe0.25Sb12 skutterudites have been achieved. Furthermore, the differential scanning calorimetry (DSC) results show that there is no skutterudite phase decomposition till 750°C for the La0.8Ba0.01Ga0.1Ti0.1Fe3CoSb12 sample. The thermal stability of the La0.8Ba0.01Ga0.1Ti0.1Fe3CoSb12 skutterudite is greatly improved. Using the developed multifilled skutterudites, the fabricated module with size of 50 mm × 50 mm × 7.6 mm possesses maximum output power of 32 W under the condition of hot/cold sides = 600°C/50°C. 相似文献
98.
改进了一种基于有限元技术分析三维裂纹应力强度因子的计算方法——虚拟裂纹闭合方法,称为改进的虚拟裂纹闭合方法.应用传统的虚拟裂纹闭合方法求解三维裂纹体应力强度因子时,对有限元模型具有一定的要求,即过裂纹前缘的有限单元裂纹面必须具有相同的面积且对称.而应用文中改进的虚拟裂纹闭合方法求解三维裂纹体应力强度因子时,裂纹前缘的裂纹面可以是任意形状.文中应用改进虚拟裂纹闭合方法,建立20结点等参元有限元模型,对三维表面裂纹应力强度因子进行了验证性的分析和讨论.通过与Newman解相比较,证明该方法适用性强且计算精度高. 相似文献
99.
Large Magnetovolume Effect Induced by Embedding Ferromagnetic Clusters into Antiferromagnetic Matrix of Cobaltite Perovskite 下载免费PDF全文
Ping Miao Xiaohuan Lin Akihiro Koda Sanghyun Lee Yoshihisa Ishikawa Shuki Torii Masao Yonemura Takashi Mochiku Hajime Sagayama Shinichi Itoh Kazutaka Ikeda Toshiya Otomo Yinxia Wang Ryosuke Kadono Takashi Kamiyama 《Advanced materials (Deerfield Beach, Fla.)》2017,29(27)
Materials that show negative thermal expansion (NTE) have significant industrial merit because they can be used to fabricate composites whose dimensions remain invariant upon heating. In some materials, NTE is concomitant with the spontaneous magnetization due to the magnetovolume effect (MVE). Here the authors report a new class of MVE material; namely, a layered perovskite PrBaCo2O5.5+x (0 ≤ x ≤ 0.41), in which strong NTE [β ≈ ?3.6 × 10?5 K?1 (90–110 K) at x = 0.24] is triggered by embedding ferromagnetic (F) clusters into the antiferromagnetic (AF) matrix. The strongest MVE is found near the boundary between F and AF phases in the phase diagram, indicating the essential role of competition between the F‐clusters and the AF‐matrix. Furthermore, the MVE is not limited to the PrBaCo2O5.5+x but is also observed in the NdBaCo2O5.5+x . The present study provides a new approach to obtaining MVE and offers a path to the design of NTE materials. 相似文献
100.
Fukuda Tomoki Nakagawa Masao Hirogaki Toshiki Aoyama Eiichi 《Forschung im Ingenieurwesen》2019,83(3):509-520
Forschung im Ingenieurwesen - Planetary gear trains (PGTs) have been used in various applications, including hybrid and electric vehicles, owing to their advantages such as compactness, light... 相似文献