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排序方式: 共有494条查询结果,搜索用时 859 毫秒
81.
Yoshikazu Suzuki Peter E. D. Morgan Koichi Niihara 《Journal of the American Ceramic Society》1998,81(12):3141-3149
Additions of 1-20 mol% Sc2 O3 or Y2 O3 to MoSi2 eliminate glassy SiO2 , which improves mechanical properties at both ambient and high temperatures. In particular, only 1 mol% ScO3 additions dramatically enhance three-point bending strength from 521 to 1081 MPa. Vickers hardness, Young's modulus, fracture toughness, and high-temperature strength are also improved by this low level of additive. The improvement of mechanical properties is attributed to the formation of crystalline silicates: Sc2 Si2 O7 , Y2 Si2 O7 , Y2 SiO5 , and Y4 Si3 O12 , which are analyzed by XRD, SEM-EDS, and TEM-EDS methods. 相似文献
82.
83.
Takashi Taya Akira Yoshida Nobusuke Yamaoka Shuichi Matsumoto Yoshikazu Yoshida 《Electrical Engineering in Japan》1998,125(2):35-43
In a large-scale broadband communication system, thousands of high-speed serial data interconnections are used and a bit synchronization circuit (a clock and data recovery circuit) is required in each of the receiver side interconnection circuits. In this paper, the requirements and the implementation of a bit synchronization circuit for the interconnection are considered, and one solution is proposed. In the proposed circuit, the oscillation phase of a VCO is directly controlled by the trigger signal extracted from the input data. Synchronization capture is quick and the circuit is applicable to burst signals. The circuit tolerates jitter and phase variation of the incoming data. The circuit requires no external components, and is suitable for an integrated circuit. The circuit was implemented using a 0.5 μm CMOS process and the data recovery operation from a 440 Mbps pseudo-random pattern was confirmed. Data acquisition is accomplished within three clock periods from 440 Mbps burst data. © 1998 Scripta Technica, Electr Eng Jpn, 125(2): 35–43, 1998 相似文献
84.
One-pot polymerization of polyimide from 3,3′,4,4′-biphenyl tetracarboxylic dianhydride (BPDA) and 4,4′-oxydianiline (ODA) was examined. The equilibrium in the polyimide with water was examined in detail in p-chlorophenol solution during the polymerization. The equilibrium constant was expressed by log K = 1.50 + 1433 (1/T). The polymerization reaction is exothermic. The molecular weight increased with decrease of temperature. © 1996 John Wiley & Sons, Inc. 相似文献
85.
Various copolymides were prepared from two acid dianhydrides (BPDA, 3,3′,4,4′-biphenyl tetracarboxylic dianhydride; PMDA, pyromelitic dianhydride) and two diamines (PPD, p-phenylene diamine; ODA, 4,4′-oxydianiline). The thermal and mechanical properties of these polyimides were examined in detail. By appropriately selecting the ratios of the acid dianhydride component and the diamine component, polyimide films having desirable mechanical and thermal characteristics can be obtained. Further, it was proved that there is a correlation between the properties and the compositions of the copolyimides and that the properties could be estimated from the compositions by the use of multiple regression analysis. © 1996 John Wiley & Sons, Inc. 相似文献
86.
Kazuo Tomita Taisuke Nagasawa Yoshikazu Kuwahara Seiji Torii Kento Igarashi Mehryar Habibi Roudkenar Amaneh Mohammadi Roushandeh Akihiro Kurimasa Tomoaki Sato 《International journal of molecular sciences》2021,22(15)
In cancer therapy, radioresistance or chemoresistance cells are major problems. We established clinically relevant radioresistant (CRR) cells that can survive over 30 days after 2 Gy/day X-ray exposures. These cells also show resistance to anticancer agents and hydrogen peroxide (H2O2). We have previously demonstrated that all the CRR cells examined had up-regulated miR-7-5p and after miR-7-5p knockdown, they lost radioresistance. However, the mechanism of losing radioresistance remains to be elucidated. Therefore, we investigated the role of miR-7-5p in radioresistance by knockdown of miR-7-5p using CRR cells. As a result, knockdown of miR-7-5p increased reactive oxygen species (ROS), mitochondrial membrane potential, and intracellular Fe2+ amount. Furthermore, miR-7-5p knockdown results in the down-regulation of the iron storage gene expression such as ferritin, up-regulation of the ferroptosis marker ALOX12 gene expression, and increases of Liperfluo amount. H2O2 treatment after ALOX12 overexpression led to the enhancement of intracellular H2O2 amount and lipid peroxidation. By contrast, miR-7-5p knockdown seemed not to be involved in COX-2 and glycolysis signaling but affected the morphology of CRR cells. These results indicate that miR-7-5p control radioresistance via ROS generation that leads to ferroptosis. 相似文献
87.
Electrospray pyrolysis, i.e. combination of electrospray and in-flight thermal treatment, has attracted much attention as a preparation method of functional ceramic particles. In this paper, we report the processing detail of spherical TiO2 nano- and microparticles by the electrospray pyrolysis method as well as their photocatalytic activity for hydrogen evolution. Titanium(IV) bis(ammonium lactato)dihydroxide aqueous solutions (TALH aq., 0.2–20 wt%) were injected into a capillary nozzle by a syringe pump (0.15–0.59 mL/min), and were electrosprayed by using DC 4 kV voltage, followed by the pyrolysis at 300–500 °C. Spherical TiO2 nano- and microparticles were successfully obtained. Effects of precursor-liquid concentration, liquid flow-rate, and pyrolysis temperature on the particle size, microstructure and functions were discussed. 相似文献
88.
Takahiro Kozawa Hideya Hattori Shuhei Ogo Yusuke Ide Yoshikazu Suzuki 《Journal of Materials Science》2013,48(22):7969-7973
A simple and mild synthetic route via a hydrothermal treatment of Mg2TiO4 has been developed to prepare brookite-type TiO2. The hydrothermal conversion of Mg2TiO4 to brookite proceeded in 1 M HCl solution even at 100 °C. The converted brookite grains were composed of the angular particles covered on the textured surface, leaving the original morphology of Mg2TiO4 grains. Compared with the commercially available TiO2 catalysts (rutile, anatase, and P25), the brookite obtained in this study showed a good photocatalytic activity toward the oxidation of benzyl alcohol to benzaldehyde under a simulated sunlight irradiation. 相似文献
89.
90.
Akira Kariyasaki Yoshikazu Yamasaki Masazumi Kagawa Tohru Nagashima Akiharu Ousaka Shigeharu Morooka 《传热工程》2013,34(1-2):28-36
A technique was developed and tested to measure the local thickness of a droplet or a liquid film on a surface of an opaque or thick single transparent plate by an interference fringe pattern that was easily formed by reflecting laser lights. Monochromatic epi-illumination through an objective lens of a conventional microscope was provided by a 5 mW or 300 mW laser and a filter to remove the noise caused by laser speckle. The incremental height difference of the liquid layer between neighboring maxima or minima of fringes was evaluated from the wavelength of the laser light and the refractive index of the liquid. Estimation error of a local inclination angle was discussed using ray tracing under parallel illumination approximation. Droplet profiles evaluated from the interferogram that were obtained by the present fringe method agreed well with those by Laser Focus Displacement Meter. Measurement was made to ensure the usefulness of the present technique. It was made clear that the contact angle of a liquid droplet could be obtained precisely and swiftly, even in small size or small contact angle, and that instantaneous three-dimensional profile of a liquid film on a bubble moving in a microchannel could be measured. The fringe method had sufficient potential to obtain more detailed information about three-dimensional characteristics of liquid film in flows such as the generation, breakdown, and growth of waves and the liquid film on a bubble at the beginning of movement. 相似文献