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21.
Ruwan Gallage Atsushi Matsuo Takeshi Fujiwara Tomoaki Watanabe Nobuhiro Matsushita Masahiro Yoshimura 《Journal of the American Ceramic Society》2008,91(7):2083-2087
Crystalline CeO2 films and patterns have been successfully fabricated in a "single-step process" at moderate temperature. In this process, the combination of the ink-jet technique and depositing the precursor on a hot substrate (≤300°C) gave crystalline CeO2 without further heat treatment. X-ray diffraction analysis revealed that the phase formed was crystallized ceria with nanosized (<10 nm) crystallites. The film thickness was several hundred nanometers and the pattern width was about 150 μm. Scanning electron microscopy analysis showed that the films and patterns were free of cracks and adhered to the substrate. This is the first report about the direct patterning of crystalline CeO2 without postfiring or posttreatments like masking, etching, etc. 相似文献
22.
Inés S. Neira Francisco Guitián Takaaki Taniguchi Tomoaki Watanabe Masahiro Yoshimura 《Journal of Materials Science》2008,43(7):2171-2178
We report an effective method for the synthesis of hydroxyapatite whiskers with sharp faceted hexagonal shape employing a
low temperature (90 °C) hydrothermal route with calcium nitrate tetrahydrate, diammonium phosphate and urea as starting materials.
The key parameters of the synthesis process i.e. duration, temperature cycle of the treatment and starting pH value are carefully
varied and the end products are investigated using powder X-ray diffraction (XRD), Raman-scattering, infrared spectroscopy
(IR), elemental analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron
microscopy (TEM), electron diffraction (ED), and high-resolution TEM (HRTEM) in order to find the optimal reaction conditions
that lead to the desired hexagonal morphology of HA whiskers. The results demonstrate that gradual and greater increase in
solution pH during the hydrothermal process favors large quantity of the single-crystalline hydroxyapatite whiskers with well
defined hexagonal morphology. 相似文献
23.
Liposome‐Based in Vitro Evolution of Aminoacyl‐tRNA Synthetase for Enhanced Pyrrolysine Derivative Incorporation 下载免费PDF全文
Dr. Atsuko Uyeda Dr. Takayoshi Watanabe Dr. Yasuhiko Kato Prof. Hajime Watanabe Prof. Tetsuya Yomo Prof. Takahiro Hohsaka Dr. Tomoaki Matsuura 《Chembiochem : a European journal of chemical biology》2015,16(12):1797-1802
Methanosarcina species pyrrolysyl‐tRNA synthetase (PylRS) attaches Pyl to its cognate amber suppressor tRNA. The introduction of two mutations (Y384F and Y306A) into PylRS was previously shown to generate a mutant, designated LysZ‐RS, that was able to attach N‐benzyloxycarbonyl‐L ‐lysine (LysZ) to its cognate tRNA. Despite the potential of LysZ derivatives, further LysZ‐RS engineering has not been performed; consequently, we aimed to generate LysZ‐RS mutants with improved LysZ incorporation activity through in vitro directed evolution. Using a liposome‐based in vitro compartmentalization (IVC) approach, we screened a randomly mutagenized gene library of LysZ‐RS and obtained a mutant that showed increased LysZ incorporation activity both in vitro and in vivo. The ease and high flexibility of liposome‐based IVC should enable the evolution of not only LysZ‐RS that can attach various LysZ derivatives but also of other enzymes involved in protein translation. 相似文献
24.
Kanichi Kamiya Tomoaki Nishijima Katsuhisa Tanaka 《Journal of the American Ceramic Society》1990,73(9):2750-2752
Dip-coated sol–gel-derived TiO2 films on an alumina substrate were converted to nonstoichiometric titanium nitride (TiN x ( x ≦ 1)) films by heating at approxmately 1000°C in NH3 gas. TiO2 films made from TiO2 sols prepared from Ti(O– i -C3 H7 )4 and stabilized by diethanolamine were more easily nitrided than those from sols containing HCl as a deflocculant reagent. This appears to be a result of the more porous structure of the former films. 相似文献
25.
Carbon nanotubes (CNTs) were produced by laser ablation of a graphite composite target in argon and nitrogen ambient gas. To investigate the effect of nitrogen gas on CNTs formation, the plasma plume was examined using optical emission spectroscopy. The vibrational temperature of C2 molecules was estimated by fitting of a Swan band spectrum. The temperature in N2 ambient gas is lower than that in Ar ambient gas. In a nitrogen atmosphere, the spectrum intensity of C2 Swan band was enhanced and CN violet system was also observed. Soot collected in the reaction tube was observed using FE-SEM and TEM. The soot deposited in the nitrogen gas contained more bundled CNTs than those in Ar ambience. 相似文献
26.
由于大部分的生物体都具有相对的自发性、功能性和有效率性,模仿生物体动作的机械研究在工程领域是非常重要的。根据这个观点,我们研究了一种基于水中微生物动作的微型推进机构。 相似文献
27.
Tokuyuki Yoshida Yasuo Yoshioka Hideki Takahashi Kazuki Misato Takahide Mori Toshiro Hirai Kazuya Nagano Yasuhiro Abe Yohei Mukai Haruhiko Kamada Shin-ichi Tsunoda Hiromi Nabeshi Tomoaki Yoshikawa Kazuma Higashisaka Yasuo Tsutsumi 《Nanoscale research letters》2014,9(1):532
Although amorphous silica nanoparticles are widely used in the production of food products (e.g., as anticaking agents), there is little information available about their absorption and biological effects after oral exposure. Here, we examined the in vitro intestinal absorption and in vivo biological effects in mice of orally administered amorphous silica particles with diameters of 70, 300, and 1,000 nm (nSP70, mSP300, and mSP1000, respectively) and of nSP70 that had been surface-modified with carboxyl or amine groups (nSP70-C and nSP70-N, respectively). Analysis of intestinal absorption by means of the everted gut sac method combined with an inductively coupled plasma optical emission spectrometer showed that the intestinal absorption of nSP70-C was significantly greater than that of nSP70. The absorption of nSP70-N tended to be greater than that of nSP70; however, the results were not statistically significant. Our results indicate that silica nanoparticles can be absorbed through the intestine and that particle diameter and surface properties are major determinants of the degree of absorption. We also examined the biological effects of the silica particles after 28-day oral exposure in mice. Hematological, histopathological, and biochemical analyses showed no significant differences between control mice and mice treated with the silica particles, suggesting that the silica nanoparticles evaluated in this study are safe for use in food production. 相似文献
28.
Masatake Yamaguchi Ken-Ichi Ebihara Mitsuhiro Itakura Tomoko Kadoyoshi Tomoaki Suzudo Hideo Kaburaki 《Metallurgical and Materials Transactions A》2011,42(2):330-339
The microscopic mechanism of grain boundary (GB) embrittlement in metals by hydrogen segregation (trapping) has been not well
understood for many years. From first-principles calculations, we show here that the calculated cohesive energy of bcc Fe
Σ3(111) and fcc Al(Cu) Σ5(012) symmetrical tilt GBs can be significantly reduced if many hydrogen atoms segregate at the GBs.
This indicates that the reduction of the cohesive energy of the GB may cause the hydrogen-induced GB embrittlement in Fe,
Al, and Cu. Considering the “mobile” effect of hydrogen during fracture, especially for the Fe system, more hydrogen atoms
coming from solid solution state can segregate on the gradually formed two fracture surfaces and reduce further the cohesive
energy. We suggest a new idea about the upper and lower critical stresses observed in the constant-load test of hydrogen-induced
delayed fracture in high-strength steels; the upper critical stress is determined by the amount (density) of “immobile” hydrogen
atoms segregated at the GB before fracture, and the lower critical stress is determined by the total amount (density) of immobile
and mobile hydrogen atoms, the latter of which segregate on the two fracture surfaces during fracture. 相似文献
29.
Guisheng Zhai Shohei Okuno Joe Imae Tomoaki Kobayashi 《Journal of Intelligent and Robotic Systems》2011,63(2):309-322
In this paper, we study a consensus problem for multi-agent systems via dynamic output feedback control. The entire system
is decentralized in the sense that each agent can only obtain output information from its neighbor agents. For practical purpose,
we assume that actuator limitation exists, and require that the consensus be achieved among the agents at a specified convergence
rate. By using an appropriate coordinate transformation, we reduce the consensus problem on hand to solving a strict matrix
inequality, and then propose to use the homotopy based method for solving the matrix inequality. It turns out that our algorithm
includes the existing graph Laplacian based algorithm as a special case. 相似文献
30.
Kazuki Shibanuma Tomoaki Utsunomiya Shuji Aihara 《International journal for numerical methods in engineering》2014,97(8):551-581
The application of the XFEM to fracture mechanics is effective, because a crack can be modeled independently from the meshes and a complex remeshing procedure can be avoided. However, the classical XFEM has an essential problem in the approximation of partially enriched elements, that is, blending elements, which causes a lack of accuracy. For the weighted XFEM, although the numerical results show the effective improvements, it was found that the issue of blending elements still remains upon detailed examination. In the present paper, the PU‐XFEM is formulated as an explicit application of the partition of unity (PU) approach to the XFEM, in order to precisely reproduce a priori knowledge of the solution by enrichment. The PU‐XFEM is applied to two‐dimensional linear fracture mechanics, and its effectiveness is verified. It is consequently found out that the PU‐XFEM precisely reproduces a priori knowledge of the solution and is therefore effective to completely solve the problem of the blending elements. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献