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排序方式: 共有504条查询结果,搜索用时 15 毫秒
391.
Licheng Liu Gabor Samjeske Shin-ichi Nagamatsu Oki Sekizawa Kensaku Nagasawa Shinobu Takao Yoshiaki Imaizumi Takashi Yamamoto Tomoya Uruga Yasuhiro Iwasawa 《Topics in Catalysis》2014,57(6-9):595-606
Carbon-supported Pd-based binary alloy electrocatalysts (Pd–Co and Pd–Ni) with different particle sizes for polymer electrolyte fuel cells were prepared by a NaBH4 reduction method and investigated to examine effects of the size and lattice constant of the Pd alloy nanoparticles on the oxygen reduction reaction (ORR) activity. The particle size and lattice constant were controlled in the wide ranges 4.2–12.1 and 0.3802–0.3948 nm, respectively by heating the catalysts in specific atmospheres. The alloy structures were characterized by X-ray diffraction, transmission electron microscopy and X-ray absorption fine structure. The electrochemical tests of the Pd–Co/C and Pd–Ni/C catalysts were performed by cyclic voltammetry and rotating disk electrode in 0.1 M HClO4. Nearly linear relationship between the lattice constant and nanoparticle size was observed with the Pd–Co and Pd–Ni nanoparticles. The nanoparticle sizes and lattice constants of the Pd–Co/C and Pd–Ni/C electrocatalysts, which influence the Pd d-band center, showed positive and inverse relations with the ORR specific activities, respectively. The mass activities of the Pd–Co/C and Pd–Ni/C electrocatalysts showed an increasing trend with the lattice expansion. 相似文献
392.
本文试图阐明日本建筑师筱原一男的建筑论。筱原一男不但对第二次世界大战后的日本建筑界,并对海外许多年轻建筑师有着持续的影响。自1953年发表处女作“久我山之家”后,筱原的建筑师生涯一直持续到2006年去世。作为建筑师,其独特之处在于与作品平行的充满魅力的言说。以住宅设计为中心活动的筱原在书写住宅论的同时,其根底一直存在着对都市的观察,这让他与同一代的建筑师形成了明确的差异。对于住宅这一建筑中的极小空间,与涵盖人类社会的巨大都市,筱原是在设计时如何认识两者间的关系的?本文通过筱原的言语和空间这紧密关联的双方进行详细分析,把筱原概念中的根本机制归纳为“异形的并置”与“虚构性”两个关键词。 相似文献
393.
文章以上马小办公楼的建筑设计作为思考的具象形式,从大众对家型和巢箱的误读入手来探讨,被日常的社会意识渗透之后,建筑的形被赋予了意义的问题。文章试图揭示当现代建筑的形被意识化之后,其本身所具有的真正意义已经无从可循。如何将建筑从日常束缚中解脱,还原形的本真,这正是作为个体的建筑师或者建筑对于现代社会的真正意义所在。 相似文献
394.
Taniguchi M Shimada J Fukuda Y Yamano M Onodera S Kaneko S Yoshikoshi A 《The Science of the total environment》2009,407(9):3153-560
Anthropogenic effects in both Osaka and Bangkok were evaluated to compare the relationships between subsurface environment and the development stage of both cities. Subsurface thermal anomalies due to heat island effects were found in both cities. The Surface Warming Index (SWI), the departure depth from the steady geothermal gradient, was used as an indicator of the heat island effect. SWI increases (deeper) with the magnitude of heat island effect and the elapsed time starting from the surface warming. Distributions of subsurface thermal anomalies due to the heat island effect agreed well with the distribution of changes in air temperature due to the same process, which is described by the distribution of population density in both Osaka and Bangkok. Different time lags between groundwater depression and subsidence in the two cities was found. This is attributed to differences in hydrogeologic characters, such as porosity and hydraulic conductivity. We find that differences in subsurface degradations in Osaka and Bangkok, including subsurface thermal anomalies, groundwater depression, and land subsidence, depends on the difference of the development stage of urbanization and hydrogeological characters. 相似文献
395.
Shan Shi Tao Wang Lina Bian Limin Zhou Liqun Zhao Shin-ichi Kuroda 《Journal of Materials Science》2011,46(22):7214-7222
In this study, nonspherical poly(methyl methacrylate)/poly(styrene-co-divinylbenzene) [PMMA/P(St-co-DVB)] particles having
multiple dents on the surface were prepared by seeded soap-free emulsion copolymerization of St and DVB (used as a crosslinker)
on spherical linear PMMA seed particles. The effect of various polymerization parameters on particle morphology, as well as
polymerization kinetics and morphological evolution, were investigated in detail. It was found that, to prepare this kind
of nonspherical particles, it was necessary to conduct the polymerization at a relatively low temperature, using batch monomer
addition mode and PMMA seed of relatively high molecular weight. The formation of the nonspherical particles was attributed
to the phase separation between the second-stage monomers and the crosslinked P(St-co-DVB) network being formed during polymerization. 相似文献
396.
Ryosuke Mizuta Fumihito Inoue Yoshihiro Sasaki Shin-ichi Sawada Kazunari Akiyoshi 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(12):2206153
Natural membrane vesicles, including extracellular vesicles and enveloped viruses, participate in various events in vivo. To study and manipulate these events, biomembrane-coated nanoparticles inspired by natural membrane vesicles are developed. Herein, an efficient method is presented to prepare organic–inorganic hybrid materials in high yields that can accommodate various lipid compositions and particle sizes. To demonstrate this method, silica nanoparticles are passed through concentrated lipid layers prepared using density gradient centrifugation, followed by purification, to obtain lipid membrane-coated nanoparticles. Various lipids, including neutral, anionic, and cationic lipids, are used to prepare concentrated lipid layers. Single-particle analysis by imaging flow cytometry determines that silica nanoparticles are uniformly coated with a single lipid bilayer. Moreover, cellular uptake of silica nanoparticles is enhanced when covered with a lipid membrane containing cationic lipids. Finally, cell-free protein expression is applied to embed a membrane protein, namely the Spike protein of severe acute respiratory syndrome coronavirus 2, into the coating of the nanoparticles, with the correct orientation. Therefore, this method can be used to develop organic–inorganic hybrid nanomaterials with an inorganic core and a virus-like coating, serving as carriers for targeted delivery of cargos such as proteins, DNA, and drugs. 相似文献
397.
Yüksel Ufuktepe Ashraf Hassan Farha Shin-ichi Kimura Tetsuya Hajiri Faruk Karadağ Md Abdullah Al Mamun Abdelmageed A. Elmustafa Ganapati Myneni Hani E. Elsayed-Ali 《Materials Chemistry and Physics》2013
Niobium nitride (NbNx) was prepared by heating Nb sample in a nitrogen atmosphere (133 Pa) at a temperature of 900 °C. The structural, electronic, nanomechanical and surface properties of the deposited layers have been determined as a function of processing time. The results suggested that the niobium nitride was crystalline in the single phase of hexagonal β-Nb2N and the nitrogen-to-niobium ratio was found to be in the range of 0.67 ± 0.03 to 0.74 ± 0.03. Longer processing times resulted in layers with higher nitrogen-to-niobium ratios. The mean grain size of these nitrides was about 18 nm. The valence band photoemission and calculated density of state spectra characterized by two peaks were associated with N 2p-Nb 4d hybridization. X-ray photoemission spectra of Nb 3p and 3d core levels revealed a strong interaction with nitrogen along with binding energy shift. As the processing time was increased, the film growth continued with consistent improvement in hardness and modulus. 相似文献
398.
Tsutomu Ioroi Tomoki Akita Shin-ichi Yamazaki Zyun Siroma Naoko Fujiwara Kazuaki Yasuda 《Electrochimica acta》2006,52(2):491-498
Carbon-supported Pt/Mo-oxide catalysts were prepared, and the reformate tolerances of Pt/MoOx/C and conventional PtRu/C anodes were examined to clarify the features and differences between these catalysts. Fuel cell performance was evaluated under various reformate compositions and operating conditions, and the CO concentrations at the anode outlet were analyzed simultaneously using on-line gas chromatography. Pt/MoOx showed better CO tolerance than PtRu with CO(80 ppm)/H2 mixtures, especially at higher fuel utilization conditions, which is mainly due to the higher catalytic activity of Pt/MoOx for the water-gas shift (WGS) reaction and electro-oxidation of CO. In contrast, the CO2 tolerance of Pt/MoOx was much worse than that of PtRu with a CO2(20%)/H2 mixture. The results of voltammetry indicated that the coverage of adsorbates generated by CO2 reduction on Pt/MoOx was higher than that on PtRu, and therefore, the electro-oxidation of H2 is partly inhibited on Pt/MoOx in the presence of 20% CO2. With CO(80 ppm)/CO2(20%)/H2, the voltage losses of Pt/MoOx and PtRu are almost equal to the sum of the losses with each contaminant component. Although the adsorbate coverage on Pt/MoOx increases in the presence of 20% CO2, CO molecules in the gas phase could still adsorb on Pt through an adsorbate ‘hole’ to promote WGS or electro-oxidation reactions, which leads to a reduction in the CO concentration under CO/CO2/H2 feeding conditions. 相似文献
399.
Satomi Ono Noriaki Yamada Shin-ichi Hirano 《Journal of the American Ceramic Society》2001,84(7):1415-1420
Potassium lithium niobate (KLN) films, which were prepared using an aqueous precursor solution, were characterized in terms of crystallinity, morphology, and electrical properties; 1.0 μm thick KLN films free from cracks and pores could be prepared on MgO(100), Pt(100)/MgO(100), and Pt(111)/Ti/SiO2 /Si substrates by multiple coating and heating at 700°C. The films were composed of compact grains and had sintered textures. The films crystallized with (310) and (540) preferred orientations on MgO(100) and Pt(100)/MgO(100) substrates. The KLN film prepared on Pt(100)/MgO(100) substrate had ɛ'= 136 and tan δ= 0.026 at 1 kHz. 相似文献
400.
Lithium ion cell safety 总被引:22,自引:0,他引:22
Shin-ichi Tobishima Koji Takei Yoji Sakurai Jun-ichi Yamaki 《Journal of power sources》2000,90(2):188-195
The safety characteristics of recent commercial lithium ion cells are examined in relation to their use for cellular phones. These are prismatic cells with an aluminum cell housing (can) and a 500–600 mA h capacity. They have one of two types of 4-V class cathodes, lithium cobalt oxide (LiCoO2) or lithium manganese oxide (LiMn2O4). This report provides results of the safety tests that we performed on lithium ion cells and outlines our views regarding their safety. 相似文献