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排序方式: 共有427条查询结果,搜索用时 14 毫秒
71.
Hideshi Ishida Shiho Ihara Chiharu Okema Shohei Yamada Genta Kawahara 《Numerical Heat Transfer, Part B: Fundamentals》2013,63(4):185-202
AbstractThis study demonstrates a global, nonparametric, noniterative optimization of time-mean value of a kind of index vibrated by time-varying forcing. It is based on the fact that the (steady) forced vibration of nonautonomous ordinary differential equation systems is well approximated by an analytical solution when the amplitude of forcing is sufficiently small and its base state without forcing is linearly stable and steady. It is applied to optimize a time-averaged heat-transfer rate on a two-dimensional thermal convection field in a square cavity with horizontal temperature difference, and the globally optimal way of vibrational forcing, i.e. the globally optimal, spatial distribution of vibrational heat and vorticity sources, is first obtained. The maximized vibrational thermal convection corresponds well to the state of internal gravity wave resonance. In contrast, the minimized thermal convection is weak, keeping the boundary layers on both sidewalls thick. 相似文献
72.
Masaya Matsuoka Masaaki Kitano Shohei Fukumoto Kazushi Iyatani Masato Takeuchi Masakazu Anpo 《Catalysis Today》2008,132(1-4):159-164
The effect of the hydrothermal treatment with aqueous NaOH solution on the photoelectrochemical and photocatalytic properties of visible light-responsive TiO2 thin films prepared on Ti foil substrate (Vis-TiO2/Ti) by a radio-frequency magnetron sputtering (RF-MS) deposition method has been investigated. The hydrothermally treated Vis-TiO2/Ti electrodes exhibited a significant increase in their photocurrent under UV and visible light irradiation as compared to untreated Vis-TiO2/Ti electrode. SEM investigations revealed that the surface morphology of Vis-TiO2/Ti are drastically changed from the assembly of the TiO2 crystallites to the stacking of nanowires with diameters of 30–50 nm with increasing hydrothermal treatment time (3–24 h), accompanying the increase in their surface area. The separate evolution of H2 and O2 from water under solar light irradiation was successfully achieved using the Vis-TiO2/Ti/Pt which is hydrothermally treated for 5 h, while the H2 evolution ratio was 15 μmol h−1 in the early initial stage, corresponding to a solar energy conversion efficiency of 0.23%. 相似文献
73.
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
74.
Takahashi S Obana Y Okada S Abe K Kera Y 《Journal of Bioscience and Bioengineering》2012,113(1):79-83
Tris(1,3-dichloro-2-propyl) phosphate (TDCPP), a flame retardant, is regarded as a potentially toxic and persistent environmental contaminant. We previously isolated a TDCPP-degrading bacterium, Sphingobium sp. strain TCM1, which, however, produced a toxic metabolite: 1,3-dichloro-2-propanol (1,3-DCP). This study was undertaken to develop a technique for complete TDCPP detoxification using strain TCM1 with a 1,3-DCP-degrading bacterium, Arthrobacter sp. strain PY1. For efficient detoxification, we designed a resting cell system and examined the effect of freezing and lyophilization treatments for preparation of their resting cells. Results show that treatments had no marked adverse effect on their activities. The TDCPP dephosphorylation by TCM1 resting cells was optimal at 30°C and pH 8.5. Also, 1,3-DCP dehalogenation by strain PY1 resting cells was optimal at 35°C and pH 9.5. Under those respective conditions, the activities were 2.48 μmol h− 1·OD660− 1 for TDCPP and 0.95 μmol h− 1·OD660− 1 for 1,3-DCP. Based on these results, we set the reaction temperature to 30°C and pH to 9.0. Then we examined the detoxification of 50 μM TDCPP using mixed resting cells at a final OD660 of 0.05 for strain TCM1 and 0.2 for strain PY1. In these conditions, TDCPP was eliminated after 1 h, but some of the resulting 1,3-DCP remained at a constant level. The increase in strain PY1 cells to a final OD660 of 4.0 decreased the TDCPP dephosphorylation rate of strain TCM1 cells but achieved complete detoxification of TDCPP during 12 h of reaction. 相似文献
75.
Toyoda S Suzuki Y Hattori S Yamada K Fujii A Yoshida N Kouno R Murayama K Shiomi H 《Environmental science & technology》2011,45(3):917-922
Wastewater treatment processes are believed to be anthropogenic sources of nitrous oxide (N(2)O) and methane (CH(4)). However, few studies have examined the mechanisms and controlling factors in production of these greenhouse gases in complex bacterial systems. To elucidate production and consumption mechanisms of N(2)O and CH(4) in microbial consortia during wastewater treatment and to characterize human waste sources, we measured their concentrations and isotopomer ratios (elemental isotope ratios and site-specific N isotope ratios in asymmetric molecules of NNO) in water and gas samples collected by an advanced treatment system in Tokyo. Although the estimated emissions of N(2)O and CH(4) from the system were found to be lower than those from the typical treatment systems reported before, water in biological reaction tanks was supersaturated with both gases. The concentration of N(2)O, produced mainly by nitrifier-denitrification as indicated by isotopomer ratios, was highest in the oxic tank (ca. 4000% saturation). The dissolved CH(4) concentration was highest in in-flow water (ca. 3000% saturation). It decreased gradually during treatment. Its carbon isotope ratio indicated that the decrease resulted from bacterial CH(4) oxidation and that microbial CH(4) production can occur in anaerobic and settling tanks. 相似文献
76.
Pei Zhao Erik Einarsson Georgia Lagoudas Junichiro Shiomi Shohei Chiashi Shigeo Maruyama 《Nano Research》2011,4(7):623-634
We present a systematic study of the effects of surfactants in the separation of single-walled carbon nanotubes (SWNTs) by
density gradient ultracentrifugation (DGU). Through analysis of the buoyant densities, layer positions, and optical absorbance
spectra of SWNT separation using the bile salt sodium deoxycholate (DOC) and the anionic salt sodium dodecyl sulfate (SDS),
we clarify the roles and interactions of these two surfactants in yielding different DGU outcomes. The separation mechanism
described here can also help in designing new DGU experiments by qualitatively predicting outcomes of different starting recipes,
improving the efficacy of DGU and simplifying post-DGU fractionation.
相似文献
77.
Shohei Ueta Jun AiharaKazuhiro Sawa Atsushi YasudaMasaki Honda Noboru Furihata 《Progress in Nuclear Energy》2011,53(7):788-793
This paper describes experiences and present status of research and development works for the high temperature gas-cooled reactor (HTGR) fuel in Japan. Recently, Very High Temperature Reactor (VHTR) is evaluated highly worldwide, and is a principal candidate for the Generation IV reactor systems. In Japan, HTGR fuel fabrication technologies have been developed through the High Temperature Engineering Test Reactor (HTTR) project in Japan Atomic Energy Agency since 1960’s. In total about 2 tons of uranium of the HTTR fuel has been fabricated successfully and its excellent quality has been confirmed through the long-term high temperature operation. Based on the HTTR fuel technologies, SiC TRISO fuel has been newly developed for burnup extension targeted VHTR. For ZrC-TRISO coated fuel as an advanced fuel designs, R&Ds for fabrication and inspection have been carried out in JAEA. The irradiation with the Japanese uniform stoichiometric ZrC coating has been completed in the cooperation with Oak Ridge National Laboratory of the United States. 相似文献
78.
Tarui N Nagano Y Sakane T Matsumoto K Kawada M Uchikawa O Ohkawa S Nakahama K 《Journal of Bioscience and Bioengineering》2002,93(1):44-47
The chiral indan derivative (S)-2 (2-[(8S)-1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl]ethyl-amine) was synthesized by enzyme-catalyzed asymmetric hydrolysis of the racemic acetamide 1 (N-[2-(1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl)ethyl]acetamide). The reaction was carried out using Bacillus sp. SUI-12 screened for the ability to hydrolyze 1 to give (S)-2 with high enantioselectivity. In a scaled-up experiment, a low reaction rate was observed. However, by changing the culture medium and the reaction conditions, it became possible to run the reaction to 40% conversion on a 10-g or more scale, obtaining (S)-2 at >;99% enantiomeric excess (ee). The (S)-2 obtained was available for the synthesis of the melatonin receptor agonist TAK-375 (N-[2-[(8S)-1,6,7,8-tetrahydro-2H-indeno[5,4-b]furan-8-yl]ethyl]propanamide). 相似文献
79.
Novel optically active carbonate-type cationics were designed and synthesized via a green method. A series of n-alkyl N,N-dimethylaminoalkyl carbonates was prepared via a two-step successive carbonate exchange reaction of diphenyl carbonate with 1-alkanol followed by the reaction of the optically active or racemic amino alcohol in the presence of triethylamine. The quaternarization of the N,N-dimethylamino group was carried out using methyl iodide. Furthermore, optically active cationics were prepared by the lipase-catalyzed enantioselective hydrolysis of the racemic cationics. Carbonate-type cationics having an isopropylene linkage showed high hydrolytic stability. They exhibited surfactant properties similar to those of the corresponding racemic cationics. Although no significant differences in the antimicrobial activities were observed owing to the stereochemistry of the cationics, the biodegradability was strongly influenced by the stereochemistry. Some optically active cationics were rapidly biodegraded by activated sludge. 相似文献
80.
Clemente C. Moredo Jr Tomoyasu Sakuno Toshinari Kawada 《The Journal of Adhesion》2013,89(1-4):183-195
Apitong (Dipterocarpus spp.) and Caribbean pine (Pinus caribaea Morelet) contain high amounts of extractives that contribute to poor bonding. To reduce, if not to eliminate, the effects of these extraneous substances, surfaces of small wood blocks were Soxhlet-extracted for 8 hours by different solvents. Wettability of the wood surfaces was then measured by droplet and dynamic methods using water and dilute NaOH as liquids. Tensile shear strengths of extracted wood bonded with aqueous vinyl polymer isocyanate (API), resorcinol formaldehyde (RF) and polyvinyl acetate (PVAc) resin adhesives were also measured. Results revealed that although Caribbean pine had much higher resin content than Apitong, the former had better wettability than the latter. Solvent extraction of the adherend with either hexane or ethanol-benzene (1:2) for 8 hours was not enough to improve its wettability but enough to improve its gluability. However, successive extraction with hexane, methanol and ethanol benzene rendered the wood satisfactorily wettable. Generally, a direct relationship between wettability and bond strength could not be observed. In a separate experiment to improve bonding strengths, test specimens were either overheated or autoclaved for 4 minutes at 125°C during the pressing period. Autoclave treatment was found to be useful in increasing the bond strengths of API, RF, PVAc and urea formaldehyde (UF)-bonded Apitong and Caribbean pine. 相似文献