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排序方式: 共有777条查询结果,搜索用时 437 毫秒
121.
Masahiro Goto Seung-Zeon Han Kwangjun Euh Norio Kawagoishi Sangshik Kim Kusno Kamil 《Journal of Materials Science》2012,47(3):1497-1503
As possible substitutes for high-strength Cu–Be alloys, Cu–6Ni–2Mn–2Sn–2Al alloys have been developed. To clarify the physical
background of the effect of trace Zr on the fatigue strength of such alloys, the initiation and propagation behavior of a
major crack that led to the fracture of the tested specimens was monitored. When the stress amplitude was less than σ
a = 350 MPa, the fatigue life of the alloys with Zr was about 2–2.5 times larger than that of the alloy without Zr. When σ
a > 350 MPa, the effect of Zr addition on the fatigue life dramatically decreases as the stress amplitude increases. The increased
fatigue life due to Zr addition resulted from an enhancement of the crack initiation life and microcrack growth life. The
enhanced crack initiation life was mainly attributed to the strengthening of grain boundaries due to the precipitation of
SnZr compounds. A statistical analysis of the behavior of multiple cracks was made to quantitatively evaluate the scatter
in fatigue behavior. The statistical analysis supported the conclusions obtained from the behavior of a major crack. 相似文献
122.
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
123.
Ma J Tang J Cheng Q Zhang H Shinya N Qin LC 《Journal of nanoscience and nanotechnology》2012,12(3):1972-1978
Single-walled carbon nanotubes were deposited on one end of the etched carbon fiber electrodes by an electrophoretic method. The carbon nanotube bundles formed a dense network on the carbon fiber surface. The electrochemical properties of the composite carbon electrodes were studied in the buffered neutral solutions. The results in cyclic voltammetry's characteristic indicate that the electrons on the electrodes transfer very fast. Furthermore, the redox reactions of dopamine (DA) on the composite electrodes show good sensitivity. When the DA concentration was 0.02 mM, the peak current in differential pulse technique reached 1.33 microA after performing the background subtraction. In addition, the simultaneous detection of DA and ascorbic acid (AA) showed that the interference effect was not observed. It was suggested that the carbon composite microelectrodes have potential applications as electrochemical sensors inside a single cell. 相似文献
124.
Amphiphilic poly(amido amine) (PAMAM) dendrons were immobilized on the surface of silica particles, following the solid phase strategy. PAMAM dendrons were constructed by the repetitive feeding of methyl acrylate and ethylenediamine as the monomers. The peripheral functionalization of amine to long alkyl ends generated the amphiphilic PAMAM dendron on the silica surface. These amphiphilic dendron-modified silica particles were applicable as new packing materials for ultrahigh pressure liquid chromatography. 相似文献
125.
Ryosuke Inagaki Norio Sadachika Dondee Navarro Mitiko Miura‐Mattausch Yasuaki Inoue 《IEEJ Transactions on Electrical and Electronic Engineering》2008,3(1):64-71
A gate leakage current model for advanced MOSFETs has been developed and implemented into the Hiroshima‐university STARC IGFET Model (HiSIM), the first complete surface‐potential‐based model. The model consists of four tunneling mechanisms, the gate to channel/bulk/source/drain, and requires totally 15 model parameters covering all bias conditions. Simulation results reproduce measurement for any device size and temperature without binning. Validity of the model has been tested with circuits that are sensitive to the change of stored charge due to tunneling current. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
126.
Mami Yamaguchi Sri Ayu Anggraini Yuki Fujio Tomoaki Sato Michael Breedon Norio Miura 《International Journal of Hydrogen Energy》2013
A highly selective hydrogen (H2) sensor has been successfully developed by using an yttria-stabilized zirconia (YSZ)-based mixed-potential-type sensor utilizing SnO2 (+30 wt.% YSZ) sensing electrode (SE) with an intermediate Al2O3 barrier layer which was coated with a catalyst layer of Cr2O3. The sensor utilizing SnO2 (+30 wt.% YSZ)-SE was found to be capable of detecting H2 and propene (C3H6) sensitively at 550 °C. In order to enhance the selectivity towards H2, a selective C3H6 oxidation catalyst was employed to minimize unwanted responses caused by interfering gases. Among the examined metal oxides, Cr2O3 facilitated the selective oxidation of C3H6. However, the addition or lamination of Cr2O3 to SnO2 (+30 wt.% YSZ)-SE was found to diminish the sensing responses to all examined gases. Therefore, an intermediate layer of Al2O3 was sandwiched between the SE layer and the catalyst layer to prevent the penetration of Cr2O3 particles into the SE layer. The sensor using SnO2 (+30 wt.% YSZ)-SE coated with a catalyst layer of Cr2O3 as well as an intermediate layer of Al2O3 exhibited a sensitive response toward H2, with only minor responses toward other examined gases at 550 °C under humid conditions (21 vol.% O2 and 1.35 vol.% H2O in N2 balance). A linear relationship was observed between sensitivity and H2 concentration in the range of 20–800 ppm on a logarithmic scale. The results of sensing performance evaluation and polarization curve measurements indicate that the sensing mechanism is based on the mixed-potential model. 相似文献
127.
This study relates to the development of ultraviolet (UV)-curable, organic–inorganic nanocomposite hard coatings for plastic lens substrates, especially for polythiourethane (PTU) and polycarbonate (PC). Novel difunctional thiourethane methacrylate (mercaptoethylsulfide-thiourethane methacrylate: coded MES-TUMA and isophorone diisocyanate-mercaptoethylsulfide-thiourethane methacrylate: coded IPDI-MES-TUMA) was synthesized to enhance the adhesive strength for PTU. On the basis of IR, 1H NMR, electron spray ionisation-mass spectrometry (ESI-MS) analysis and gel permeation chromatography (GPC), the expected structures were confirmed. These difunctional thiourethane methacrylates were easily mixed with multifunctional urethane acrylate, surface-modified ZrO2–TiO2 nanoparticles and photoinitiator in coating formulations. The UV-cured organic–inorganic nanocomposites were very useful as hard coatings for high refractive index plastic lenses such as PTU and PC. 相似文献
128.
Quaternary ammonium salts are frequently used as antibacterial agent that disrupts cell membrane through the binding of their ammonium cations to anionic sites in the outer layer tissue of bacteria. This article describes the synthesis of quaternary ammonium salt-type antibacterial agents with a phosphate group that strongly binds to hydroxyapatite and bromide ion as counterion. Evaluation of the antibacterial activity of the synthesized compounds in terms of minimum inhibitory concentration (MIC test) showed that the compounds exhibit an excellent antibacterial activity on a variety of bacteria including Gram-positive and Gram-negative bacteria, yeast, and fungi. 相似文献
129.
In this work, we aimed to develop a scaffold of chitosan (CS) with a porous sponge structure for an artificial skin. The scaffolds were prepared from both CS/citric and CS/acetic solutions. In addition, the cast films were also prepared from the same solutions to compare some of their properties. They were characterized using WAXD, FTIR, DSC, tensile measurements, and SEM observation. It was found that CS/acetate had low crystallinity but CS/citrate was in an amorphous state, resulting in a large ductility with rubbery softness. Despite the different morphologies of CS/citrate and CS/acetate scaffolds, both scaffolds exhibited the wound healing effect available for tissue engineering. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献
130.
Sasaki K Morita M Matsumoto N Sasaki D Hirano S Ohmura N Igarashi Y 《Journal of Bioscience and Bioengineering》2012,114(1):64-69
The aim of this study was to show the effectiveness of the membrane free bioelectrochemical system (BES) using three electrodes on inhibition of methanogenesis and construction of hydrogen fermentation from the artificial garbage slurry. The electrical redox-potential on the working electrode was adjusted to -1.0V (vs. Ag/AgCl) that has positive effect on methanogenesis. The redox-potential on the counter electrode was measured to be 1.6V. The pH in the effluents was 5.5-6.4. Hydrogen production rate at the cathode side was similar to that at the anode side and much higher than that calculated from current, and reached a maximum of 2445±815 (average±standard deviation) mL?L(-1)?d(-1) at an organic loading rate of 58.7g dichromate chemical oxygen demand per L d(-1). Methane production was negligible throughout the experiment. Acetate and butyrate were the main products of the fermentation using a BES; these offered favorable conditions for hydrogen production. The bacterial community in the bioelectrochemical hydrogen fermentor differed from that in the methanogenic seed sludge and included hitherto unknown species. These results show that high redox-potential on the anodic electrode and acidic pH in the membrane free BES can be utilized for hydrogen fermentation from the artificial garbage slurry by avoiding methanogenesis. 相似文献