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排序方式: 共有946条查询结果,搜索用时 78 毫秒
871.
Junichi Iwasawa Ryoichi Nishimizu Masahiro Tokita Masakatsu Kiyohara Keizo Uematsu 《Journal of the American Ceramic Society》2007,90(8):2327-2332
Dense yttrium oxide film was prepared on a quartz substrate by the aerosol deposition process at the room temperature. The deposition rate was very high, 60 m/h. Thick film of 10 m was easily achievable on the quartz substrate. Transmission electron microscopy showed that the film was highly dense without voids and was composed of randomly oriented Y2 O3 crystallites of sizes smaller than 20 nm. The interface between the film layer and the quartz substrate was homogeneous. The film (2-m thick) had a high transmittance (55–85%) in the wavelength region of 250-800 nm. The mechanical properties of the film were very good. The adhesion force of the interface between the Y2 O3 layer and the quartz substrate was over 80 MPa. The Vickers hardness of the film was 7.7 GPa. The film also had an excellent plasma resistance in a gas mixture of CF4 /O2 . Outstanding results were noted in eroded depth, surface roughness, nanostructure, and transmittance change after plasma exposure of the film. 相似文献
872.
城市降雨径流模型-修正RRL法及其改进 总被引:2,自引:0,他引:2
对修正RRL法进行改进,在修正RRL法中加入非线性水库方程来描述地面径流汇流过程,管道汇流采用能够考虑压力水头的非恒定流方程来代替修正RRL法中的简化无压管流模型,使得改进后的模型可以处理自由水面或压力管流问题。通过实例研究,验证了改进后的模型的可应用性和有效性。 相似文献
873.
UV light-activated highly efficient photoelectrocatalytic decomposition of biorelated compounds and biowastes was successfully achieved by a Biophotochemical Cell (BPCC) comprising a nanoporous semiconductor film photoanode and an O2-reducing cathode with high internal quantum efficiency over 100. Major decomposition reaction was dark auto-oxidation of the activated substrate radicals (R?) by the bulk O2 into CO2 or/and to N2. Photocatalytic decomposition of aqueous solutions of urea, ammonia, pig urine, and oxalic acid was investigated. Combination cells were fabricated comprising a photoanode/cathode unit for activation of organic compounds and a large volume chamber for autooxidation of activated substrates. 相似文献
874.
Kenichi Tanaka Toshio Amita Takashi Satou Kimihiro Koba Junichi Kusumoto Akihiro Kanaya 《International Journal of Pressure Vessels and Piping》2009
Toughness of CrMoV cast steel for steam turbine casings operated at elevated temperature can be degraded during the operation. It is important to measure the degradation under operation to estimate the damage and the maintenance interval. However, conventional testing methods for fracture toughness require large specimens and it is impractical for successive operation after sampling these specimens. 相似文献
875.
Mugihito Oshiro Hideaki Shinto Yukihiro Tashiro Noriko Miwa Tatsuya Sekiguchi Masahiro Okamoto Ayaaki Ishizaki Kenji Sonomoto 《Journal of Bioscience and Bioengineering》2009,108(5):376-384
We proposed a kinetic simulation model of xylose metabolism in Lactococcus lactis IO-1 that describes the dynamic behavior of metabolites using the simulator WinBEST-KIT. This model was developed by comparing the experimental time-course data of metabolites in batch cultures grown in media with initial xylose concentrations of 20.3–57.8 g/l with corresponding calculated data. By introducing the terms of substrate activation, substrate inhibition, and product inhibition, the revised model showed a squared correlation coefficient (r2) of 0.929 between the experimental time-course of metabolites and the calculated data. Thus, the revised model is assumed to be one of the best candidates for kinetic simulation describing the dynamic behavior of metabolites. Sensitivity analysis revealed that pyruvate flux distribution is important for higher lactate production. To confirm the validity of our kinetic model, the results of the sensitivity analysis were compared with enzyme activities observed during increasing lactate production by adding natural rubber serum powder to the xylose medium. The experimental results on pyruvate flux distribution were consistent with the prediction by sensitivity analysis. 相似文献
876.
Inoue T. Nakayama T. Ando Y. Kosaki M. Miwa H. Hirata K. Uemura T. Miyamoto H. 《Electron Devices, IEEE Transactions on》2008,55(2):483-488
To improve the pinched-off characteristics of an AlGaN/GaN heterojunction field effect transistor (HJFET), the conduction band potential of an incorporated ALxGa1-xN buffer is designed to be upwardly convex in a band diagram. This approach utilizes the polarization effects specific to GaN-based materials by lowering the Al content x from 30% to 5% almost linearly toward the front side. Fabricated field effect transistors (FETs) adopting the designed buffer have demonstrated the following advanced characteristics in comparison to those of a FET adopting a conventional GaN buffer: less than one-tenth of the buffer leakage current, a gate-to-drain breakdown voltage BVgd twice or more as high, and remarkably improved carrier confinement and pinched-off behavior. The FETs are operated in an enhancement mode with a gate-to-channel distance thick enough to prevent tunneling current through the gate. 相似文献
877.
Yuji Honda Tetsuya Yamazaki Naoya Katsumi Naoko Fujita Kenji Matsumoto Masanori Okazaki Shoji Miwa 《Journal of Applied Glycoscience》2019,66(2):51
We investigated the physicochemical properties of starches extracted from 8 lotus (Nelumbo nucifera Gaertn.) rhizomes harvested in different months (September 2012 to May 2013). The physicochemical properties of the lotus starches depended on the harvest date. The peak viscosity (PV) in the Rapid Visco-Analyser analysis, and the viscosity at 65 °C (V65) in the rotational viscometer analysis were significantly lower in SEP starch (extracted from the September-harvested sample) than in the other lotus starches. The Spearman’s rank correlation coefficients of potassium ion (K) content vs. V65 and of K content vs. PV were 0.905 and 0.714, respectively, indicating that potassium ions are important for expressing the pasting properties of lotus starch. Principal component analysis suggested that the potassium, magnesium, calcium, and phosphorus contents are important for displaying both the pasting and gelatinization properties of the lotus starches. Meanwhile, the cluster analysis revealed that physicochemical properties of the SEP starch were different from those of the starches harvested in other months. 相似文献
878.
Sameshima Y Honda K Kato J Omasa T Ohtake H 《Journal of Bioscience and Bioengineering》2008,106(2):199-203
Rhodococcus opacus B-4 is a benzene-tolerant bacterium which was isolated from a gasoline-contaminated soil sample. We previously demonstrated that this organism was able to survive and exhibit biocatalytic activity in anhydrous organic solvents for at least 5 d. In the present study, we cloned the alkB1 and alkB2 genes encoding alkane hydroxylases from R. opacus B-4. Heterologous expression of the alkB1 and alkB2 genes in Escherichia coli JM109 showed that they encode functional alkane hydroxylases with a substrate range of C(5)-C(16). Promoters of the alkB1 and alkB2 genes, designated P(alkB1) and P(alkB2), respectively, were examined for activity in anhydrous bis (2-ethylhexyl) phthalate (BEHP) containing C(5)-C(16)n-alkanes. Two recombinant plasmids, pP(alkB1)EGFP and pP(alkB2)EGFP, were constructed by inserting the egfp gene downstream of P(alkB1) and P(alkB2), respectively and transformed into R. opacus B-4. Resting cells of R. opacus B-4 (pP(alkB1)EGFP) showed greater levels of EGFP fluorescence in anhydrous BEHP than in 0.85% NaCl, when C(8)-C(16)n-alkanes were supplied as an inducer. Furthermore, n-alkane inducibility of P(alkB1) activity in anhydrous BEHP was noticeably different from that in 0.85% NaCl. This paper presents the first evidence that bacteria can express their genes in essentially anhydrous organic solvents. 相似文献
879.
Yigang Yan Hai-Wen Li Toyoto Sato Naoyashi Umeda Kazutoshi Miwa Shin-ichi Towata Shin-ichi Orimo 《International Journal of Hydrogen Energy》2009
Y(BH4)3 was prepared by liquid-phase synthesis, and its dehydriding and rehydriding properties were systematically investigated by performing thermogravimetry and differential thermal analysis (TG-DTA) and powder X-ray diffraction (XRD) measurement. The dehydriding reaction of Y(BH4)3 starts at appropriately 460 K, and a total of 7.8 wt% of hydrogen is released up to 773 K. Phase transformation and melting are observed in Y(BH4)3 at approximately 474 K and 499 K, respectively. Both DTA and XRD measurement results indicate that the decomposition of Y(BH4)3 proceeds via multistep dehydriding reactions accompanied with the formation of an intermediate phase. Furthermore, Y(BH4)3 is proved to be partially rehydrided. 相似文献
880.
Development of a high-speed pumping system for ultra high vacuum (UHV) process dose not reduce only cost and waiting time for experiment and production, but also reduces CO2 emission that is known as one of the serious causes in the global warming problem. Reduction of vapor water concentration in a purge gas line would be one of the most effective measures to reduce pumping time to UHV. We carried out control of water vapor in a nitrogen gas purge line in addition to surface treatments of chambers using buff polishing and electrolytic polishing, followed by measurement of outgassing rate of the chambers. Under the reasonable control of the water vapor, the pumping time to reach the pressure of 1 × 10−6 Pa was able to be shortened with two orders of the magnitude. And it was also found that the main residual gas in the chamber was hydrogen after pumping down with the low concentration of water vapor. The quality of residual gas was equivalent to the quality in a baked UHV system. The introduction of well controlled nitrogen gas to the vacuum system which was not baked out during its pumping has proved a pressure of 3 × 10−8 Pa for 24 h in the chamber without orifice. 相似文献