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排序方式: 共有365条查询结果,搜索用时 491 毫秒
71.
Ueki Kosuke Ueda Kyosuke Nakai Masaaki Nakano Takayoshi Narushima Takayuki 《Metallurgical and Materials Transactions A》2018,49(6):2393-2404
Metallurgical and Materials Transactions A - Microstructural changes were observed during the plastic deformation of ASTM F90 Co-20Cr-15W-10Ni (mass pct) alloy heat-treated at... 相似文献
72.
73.
Nabeshi H Yoshikawa T Matsuyama K Nakazato Y Arimori A Isobe M Tochigi S Kondoh S Hirai T Akase T Yamashita T Yamashita K Yoshida T Nagano K Abe Y Yoshioka Y Kamada H Imazawa T Itoh N Kondoh M Yagi K Mayumi T Tsunoda S Tsutsumi Y 《Nanotechnology》2012,23(4):045101
We previously reported that well-dispersed amorphous nanosilicas with particle size 70 nm (nSP70) penetrate skin and produce systemic exposure after topical application. These findings underscore the need to examine biological effects after systemic exposure to nanosilicas. The present study was designed to examine the biological effects. BALB/c mice were intravenously injected with amorphous nanosilicas of sizes 70, 100, 300, 1000 nm and then assessed for survival, blood biochemistry, and coagulation. As a result, injection of nSP70 caused fatal toxicity, liver damage, and platelet depletion, suggesting that nSP70 caused consumptive coagulopathy. Additionally, nSP70 exerts procoagulant activity in vitro associated with an increase in specific surface area, which increases as diameter reduces. In contrast, nSP70-mediated procoagulant activity was absent in factor XII-deficient plasma. Collectively, we revealed that interaction between nSP70 and intrinsic coagulation factors such as factor XII, were deeply related to nSP70-induced harmful effects. In other words, it is suggested that if interaction between nSP70 and coagulation factors can be suppressed, nSP70-induced harmful effects may be avoided. These results would provide useful information for ensuring the safety of nanomaterials (NMs) and open new frontiers in biological fields by the use of NMs. 相似文献
74.
Hidenori Hiramatsu Takayoshi Katase Yoshihiro Ishimaru Akira Tsukamoto Toshio Kamiya Keiichi Tanabe Hideo Hosono 《Materials Science and Engineering: B》2012,177(7):515-519
Relationships between microstructure and transport properties of bicrystal grain boundary (BGB) junctions were studied in cobalt-doped BaFe2As2 (BaFe2As2:Co) epitaxial films grown on [0 0 1]-tilt bicrystal substrates of MgO and (La, Sr)(Al, Ta)O3 with misorientation angles θGB = 3–45°. The θGB of BaFe2As2:Co BGBs were exactly transferred from those of the bicrystal substrates. No segregation of impurities was detected at the BGB junction interfaces, and the chemical compositions of the BGBs were uniform and the same as those in the bulk film regions. A transition from a strongly-coupled GB behavior to a weak-link behavior was observed in current density–voltage characteristics under self-field around θGB ~ 9°. The critical current density decreased from (1.2–1.6) × 106 A/cm2 of the intragrain transport to (0.7–1.1) × 105 A/cm2 of θGB = 45° because supercurrent becomes more governed by Josephson current with increasing θGB. 相似文献
75.
Koji Hagihara Kenta Fujii Aira Matsugaki Takayoshi Nakano 《Materials science & engineering. C, Materials for biological applications》2013,33(7):4101-4111
Mg- or Ca-based intermetallic compounds of Mg2Ca, Mg2Si, Ca2Si and CaMgSi are investigated as possible new candidates for biodegradable implant materials, attempting to improve the degradation behavior compared to Mg and Ca alloys. The reactivity of Ca can be indeed reduced by the formation of compounds with Mg and Si, but its reactivity is still high for applications as an implant material. In contrast, Mg2Si shows a higher corrosion resistance than conventional Mg alloys while retaining biodegradability. In cytotoxicity tests under the severe condition conducted in this study, both pure Mg and Mg2Si showed relatively high cytotoxicity on preosteoblast MC3T3-E1. However, the cell viability cultured in the Mg2Si extract medium was confirmed to be better than that in a pure Mg extract medium in all the conditions investigated with the exception of the 10% extract medium, because of the lower corrosion rate of Mg2Si. The cytotoxicity derived from the Si ion was not significantly detected in the Mg2Si extract medium in the concentration level of ~ 70 mg/l measured in the present study. For aiming the practical application of Mg2Si as an implant material, however, its brittle nature must be improved. 相似文献
76.
Poly(vinyl alcohol) membrane was coated with organic-silica nanocomposite derived from perhydropolysilazane. For organic composite part, polystyrene-block-poly(4-vinyl phenol) [SP], poly(tert-butyl acrylate-co-2-hydroxyethyl methacrylate) [BA] and poly(butyl methacrylate-co-2-hydroxyethyl methacrylate) [BMA] were used. Water vapor barrier property of coat membrane was measured at relative humidity = 96% by a cup method. The coat films of nanocomposites with SP-silica and BA-silica showed better water vapor barrier property than those of the silica coat film without organic polymer and BMA-silica composites. The surface morphologies of the coat films were investigated by scanning electron microscopy and atomic force microscopy. The addition of organic polymer to silica prevented the crack formation of coat layer on the substrate. 相似文献
77.
Hiraki T Sekiguchi T Kato C Hatada Y Maruyama T Abe F Konishi M 《Journal of Bioscience and Bioengineering》2012,113(2):220-223
For efficient oxygen supply to pressurized culture, we developed a method using a highly pressurized membrane reactor with an air-saturated medium circulation system. The new method increased the cell growth of aerobic yeast approximately 20 folds larger than that in the case of using a conventional method. 相似文献
78.
Jingyao Zhang Takayoshi Aoki 《Computer-Aided Civil and Infrastructure Engineering》2020,35(6):615-627
System identification is the key technique for damage detection in application of structural health monitoring. In contrast to modal parameters, changes in structural parameters (stiffness and damping) are more sensitive and straightforward for damage detection of a building under severe environments such as earthquakes. In this study, we first present the fundamental theory for direct identification of structural parameters by using the frequency‐domain responses of a shear building in frequent earthquakes. Shear buildings are widely adopted for structural analysis of low‐ and middle‐rise buildings in practice. Modal information, in terms of spectrum ratios, is implicitly used in the proposed noniterative algorithm to greatly improve the estimation accuracy as well as to avoid any human intervention. The fundamental theory is validated by the numerical and physical examples. The numerical examples are further used to verify the high efficiency, accuracy, and robustness of the proposed algorithm against noised responses. The proposed algorithm is highly efficient because no iterative computation is necessary, while the necessary Fourier transform of the dynamic responses is not very time consuming. Furthermore, the proposed algorithm is highly accurate and robust because (a) the fundamental theory behind the algorithm is straightforward: the identification values should have the same value irrespective of circular frequencies, according to the theory; (b) error in modal parameter identification is completely avoided because it is unnecessary to identify the exact values of the frequencies as in many existing methods. 相似文献
79.
Tadashi C Ozawa Katsutoshi Fukuda Yasuo Ebina Kosuke Kosuda Akira Sato Yuichi Michiue Keiji Kurashima Takayoshi Sasaki 《Science and Technology of Advanced Materials》2011,12(4)
La–Eu solid solution nanosheets La2/3−xEuxTa2O7 have been synthesized, and their photoluminescence properties have been investigated. La2/3−xEuxTa2O7 nanosheets were prepared from layered perovskite compounds Li2La2/3−xEuxTa2O7 as the precursors by soft chemical exfoliation reactions. Both the precursors and the exfoliated nanosheets exhibit a decrease in intralayer lattice parameters as the Eu contents increase. However, there is a discontinuity in this trend between the nominal Eu content ranges x≤ 0.3 and x ≥ 0.4. This discontinuity is attributed to the difference in degree of TaO6 octahedra tilting for the La- and Eu-rich phases. La2/3−xEuxTa2O7 nanosheets exhibit red emission, characteristic of the f–f transitions in Eu3+ photoactivators. The photoluminescence emission can be obtained from both host and direct photoactivator excitation. However, photoluminescence emission through host excitation is much more dominant than that through direct photoactivator excitation, and this behavior is consistent with that of all the other rare-earth photoactivated nanosheets reported previously. The absolute photoluminescence quantum efficiency of the La2/3−xEuxTa2O7 nanosheets increases as the experimentally determined Eu contents increase up to x=0.45 and decrease above it. This result is in good agreement with the optimum photoactivator concentration expected from the percolation theory. These solid solution La2/3−xEuxTa2O7 nanosheets are excellent models for validating the theory of optimum photoactivator concentration in the truly two-dimensional photoactivator matrix. 相似文献
80.
Suturin SM Sokolov NS Banshchikov AG Kyutt RN Sakata O Shimura T Harada J Tabuchi M Takeda Y 《Journal of nanoscience and nanotechnology》2011,11(4):2990-2996
Surface X-ray diffraction was applied to study structure of the fluorite-silicon interface forming upon epitaxial growth of CaF2 on Si(001) surface kept at 750 degrees C. Samples with CaF2 coverage of 1.5-4 (110)-monolayers were grown and in-situ characterized using synchrotron radiation. The 3 x 1-like surface reconstruction was observed in agreement with the previous studies by electron diffraction. Interestingly, a well pronounced splitting of the fractional x 1/3 reflections was revealed. This splitting was ascribed to the effect of antiphase domain boundaries in the row-like structure of the interface layer. The in-plane integrated intensities were used to reconstruct two-dimensional atomic structure of the high-temperature CaF2/Si(001) interface. 相似文献