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排序方式: 共有509条查询结果,搜索用时 15 毫秒
71.
Kyoko Hori Masahiro Fukuta Hirokazu Shimooka Shigemi Kohiki Toetsu Shishido Masaoki Oku Masanori Mitome Yoshio Bando 《Journal of Alloys and Compounds》2005,390(1-2):261-264
β-Ga2O3 nanocolumns straightened and crossed perpendicularly each other were deposited on MgO (1 0 0) substrate by vapor phase transport method. Growth of the nanocolumns was examined at steps of 1000, 1050, and 1200 °C in elevation of source-boat temperature. We have drawn out the substrate from deposition-tube at each source-boat temperatures of 1000, 1050, and 1200 °C. Scanning electron microscopy of the sample with source-boat temperature of 1200 °C demonstrated that the straightened and elongated nanocolumns are crossing perpendicularly each other. Typical lengths of the nanocolumns were in the range of several hundreds nanometers below 1050 °C, and those of 1200 °C were in the range of ten to fifteen hundreds nanometers. Diameters of the nanocolumns stayed in the range of few hundreds nanometers, notwithstanding variation of the source temperature. X-ray diffraction and transmission electron microscopy with energy dispersive X-ray spectroscopy revealed that the nanocolumns are monoclinic β-Ga2O3 crystal, and the (4 0 0) plane of β-Ga2O3 nanocolumns is parallel to the (1 0 0) plane of MgO substrate. 相似文献
72.
Mitsuhiro Hibino Hirokazu Kawaoka Haoshen Zhou Itaru Honma 《Electrochimica acta》2004,49(28):5209-5216
Hydrated sodium manganese oxide was synthesized by reducing permanganate ion using ethanol by a sol–gel method. By including acetylene black in the synthetic reaction, we obtained composite materials in which sodium manganese oxide hydrate particles were small and mixed well with the acetylene black. We evaluated those composites as a lithium battery cathode and found that they showed 170 mA h g−1 under 5 mA g−1 and 117 mA h g−1 under 5 A g−1 on the basis of composite weight. This rapid discharge performance was probably caused by the favorable contact condition of the composite constituents. 相似文献
73.
Lian Gao Qiang Li Weiling Luan Hirokazu Kawaoka Tohru Sekino Koichi Niihara 《Journal of the American Ceramic Society》2002,85(4):1016-1018
This communication reports on the preparation and electric properties of dense nanocrystalline ZnO ceramics. By spark plasma sintering, nanocrystalline (∼100 nm) ZnO ceramics with a high density of 98.5% were obtained at a very low temperature of 550°C. Electric property measurement revealed a novel conduction nonlinearity in the sample sintered at 500°C. This phenomenon is due to the nanometerization of ZnO crystal and the grain boundary layer with an amorphous interfacial layer. 相似文献
74.
Hirokazu Chazono Tomoya Hagiwara 《International Journal of Applied Ceramic Technology》2005,2(1):45-50
Structure–property relationship in BaTiO3 (BT)-based dielectrics for multi-layer ceramic capacitors with nickel internal electrode was investigated using samples having various HoO3/2 concentrations by measuring temperature characteristics of capacitance, voltage–current characteristics, lifetime at highly accelerated life test, high-resolution analytical electron microscope, and frequency response at elevated temperature and ultra-low frequency. It was concluded that the addition of Ho affected the shell and grain boundary (GB) characteristics. Incorporation of Ho into BT perovskite lattice and the change in GB characteristics along with the doped concentration of HoO3/2 were discussed to better understand the role of doped Ho2 O3 . 相似文献
75.
Masaaki Nagatsu Takaaki Yoshida Marcel Mesko Akihisa Ogino Takafumi Matsuda Takayuki Tanaka Hirokazu Tatsuoka Kenji Murakami 《Carbon》2006,44(15):3336-3341
The use of graphene layer encapsulated catalytic metal particles for the growth of narrower multi-walled carbon nanotubes (MWCNTs) has been studied using plasma-enhanced chemical vapor deposition and conventional thermal CVD. Ni–C or Fe–C composite nanoclusters were fabricated using the dc arc discharge technique with metal–graphite composite electrodes carrying a current of 100–200 A in a stainless-steel chamber filled with He and CH4 mixture gas at 27 kPa. Nano-sized grains with diameters less than 10 nm were fabricated and deposited on a Si substrate, and were used as a catalyst for MWCNT growth. Structural analyses of the composite nanoclusters and MWCNTs were carried out using transmission electron microscopy. The results show that the diameters of the MWCNTs were reduced from 50–100 nm for a conventional Ni thin film-evaporated Si substrate to a minimum of roughly 2–4 nm in the present study. 相似文献
76.
Kaoru Dokko Jun-ichi Sugaya Hirokazu Munakata Kiyoshi Kanamura 《Electrochimica acta》2005,51(5):966-971
Fabrications of micro-dot electrodes of LiCoO2 and Li4Ti5O12 on Au substrates were demonstrated using a sol-gel process combined with a micro-injection technology. A typical size of prepared dots was about 100 μm in diameter, and the dot population on the substrate was 2400 dots cm−2. The prepared LiCoO2 and Li4Ti5O12 micro-dot electrodes were characterized with scanning electron microscopy, X-ray diffraction, micro-Raman spectroscopy, and cyclic voltammetry. The prepared LiCoO2 and Li4Ti5O12 micro-dot electrodes were evaluated in an organic electrolyte as cathode and anode for lithium micro-battery, respectively. The LiCoO2 micro-dot electrode exhibited reversible electrochemical behavior in a potential range from 3.8 to 4.2 V versus Li/Li+, and the Li4Ti5O12 micro-dot electrode showed sharp redox peaks at 1.5 V. 相似文献
77.
Kazushige Murayama Shigehiko Suzuki Hikaru Kobori Hirokazu Ito Shinji Ogoe 《木材化学与工艺学杂志》2018,38(3):224-232
Maleic anhydride-modified polypropylene (MAPP) is a compatibilizer used to improve the physical and mechanical properties of many wood/plastic composites (WPCs). The properties of WPCs containing MAPP differ according to the characteristics of the specific MAPP that it is used. In this study, the physical and mechanical properties, including shear viscosity, of polypropylene-based WPCs containing different types of MAPP were investigated before and after water absorption. The shear viscosity of MAPP increased with increasing molecular weight, but remained nearly constant for WPCs containing different types of MAPP. In dry conditions, the strongest WPC contained the MAPP with the highest acid value. The highest flexural modulus was observed with the WPC containing the MAPP with the highest molecular weight. In wet conditions, the WPC exhibiting the best mechanical properties contained a MAPP with a molecular weight of 58,000. 相似文献
78.
Poly(N‐isopropylacrylamide) gel‐based macroporous monolith for continuous‐flow recovery of palladium(II) ions
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Hirokazu Seto Hikaru Matsumoto Makoto Shibuya Takanori Akiyoshi Yu Hoshino Yoshiko Miura 《应用聚合物科学杂志》2017,134(4)
Macroporous monoliths, composed of thermoresponsive, tertiary‐aminated, and crosslinking monomers, were prepared for continuous‐flow separation of palladium(II) ions. N ‐Isopropylacrylamide was required to form the porous structure in the monoliths, indicating that the mechanism of porous structure formation involved polymerization‐induced phase separation of the poly(N ‐isopropylacrylamide) gel. Tertiary‐aminated monoliths showed adsorption selectivity for palladium(II) ions in hydrochloric media, compared with copper(II) ions. The maximum capacities of the monoliths with tertiary amine contents of 10, 20, 30, and 70 mol % for palladium(II) ions were 0.6, 1.1, 1.3, and 2.3 mmol/g, respectively. Darcy's permeabilities of water through the macroporous monolith were 10?14 to 10?13 m2, and those were comparable to that through a commercially available membrane filter with a pore size of several micrometers. In the continuous‐flow process, the macroporous monolith with tertiary amine selectively adsorbed palladium(II) ions in the coexistence of copper(II) ions with 10 times higher concentration than the palladium(II) ions. The palladium(II) ions were eluted from the macroporous monolith, and the concentration of palladium(II) ions in the eluate was up to 45 times of that in the feed solution. The average enrichment factor and total recovery percentage of palladium(II) ions were 8.7 times and 95%, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44385. 相似文献
79.
[Correction Notice: An erratum for this article was reported in Vol 27(3) of Health Psychology (see record 2008-08834-013). In the aforementioned article, the second sentence of the Results portion of the abstract should read: Among participants most attracted to Whites, group devaluation was associated with higher levels of nonprimary partner UAI; but was associated with lower levels of nonprimary partner UAI among those most attracted to non-Whites.] Objective: This study examined depressive mood and HIV-risk behavior in relation to perceived group devaluation and group identity. Design: Cross-sectional survey of 192 Asian gay men. Main Outcome Measures: Depressive mood assessed using the Centers for Epidemiological Studies Depression Scale (CES-D) and self-reported receptive or insertive unprotected anal intercourse (UAI) in the past 3 months. Results: Group devaluation was positively associated with depressive mood. Among participants most attracted to Whites, group devaluation was associated with higher levels of nonprimary partner UAI, among those most attracted to non-Whites. Among participants reporting higher levels of group devaluation, those with more positive personal evaluations of the Asian gay community had lower levels of total UAI compared to those with more negative personal evaluations of the Asian gay community. Conclusions: Results suggest that group devaluation is associated with higher levels of depressive mood among Asian gay men. Asian gay men most attracted to non-Whites or hold more positive evaluations of their group may be buffered from the influence of high perceived group devaluation on UAI. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.
Reports an error in "Perceived group devaluation, depression, and HIV-risk behavior among Asian gay men" by David H. Chae and Hirokazu Yoshikawa (Health Psychology, 2008[Mar], Vol 27[2], 140-148). In the aforementioned article, the second sentence of the Results portion of the abstract should read: Among participants most attracted to Whites, group devaluation was associated with higher levels of nonprimary partner UAI; but was associated with lower levels of nonprimary partner UAI among those most attracted to non-Whites. (The following abstract of the original article appeared in record 2008-03424-002.) Objective: This study examined depressive mood and HIV-risk behavior in relation to perceived group devaluation and group identity. Design: Cross-sectional survey of 192 Asian gay men. Main Outcome Measures: Depressive mood assessed using the Centers for Epidemiological Studies Depression Scale (CES-D) and self-reported receptive or insertive unprotected anal intercourse (UAI) in the past 3 months. Results: Group devaluation was positively associated with depressive mood. Among participants most attracted to Whites, group devaluation was associated with higher levels of nonprimary partner UAI, among those most attracted to non-Whites. Among participants reporting higher levels of group devaluation, those with more positive personal evaluations of the Asian gay community had lower levels of total UAI compared to those with more negative personal evaluations of the Asian gay community. Conclusions: Results suggest that group devaluation is associated with higher levels of depressive mood among Asian gay men. Asian gay men most attracted to non-Whites or hold more positive evaluations of their group may be buffered from the influence of high perceived group devaluation on UAI. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献