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排序方式: 共有2038条查询结果,搜索用时 31 毫秒
101.
Yusuke Yamada Atsushi Ueda Zhen Zhao Toru Maekawa Kengo Suzuki Tadashi Takada Tetsuhiko Kobayashi 《Catalysis Today》2001,67(4):325-387
The rapid evaluation of catalysis is an indispensable technology for the success of combinatorial chemistry. A small-sized, less expensive, easily operating screening is desirable for parallel settings which dramatically shortens the evaluation time. Recent advances in gas sensors have enabled us to use them for the rapid evaluation of oxidation catalysis. Three typical catalytic oxidations over metal oxide catalysts were evaluated by gas sensor systems optimized for each catalytic system. The first one is the total oxidation of carbon monoxide in air. Five catalytic combustion-type gas sensors were used in a parallel reactor system to shorten the evaluation time. The second one is the oxidative dehydrogenation (ODH) of ethane over the mixed oxide of nickel and iron. The evaluation of the ODH catalysis was performed by a selective olefin sensor which determines the concentration of C2H4 in C2H6. The third one is the selective oxidation catalysis of propane over alkali modified Fe/SiO2. The effluents including CO, CO2, aldehydes and ketones in propane were analyzed by the CO, CO2 and semiconductor-type gas sensors selective toward aldehydes and ketones. These evaluation results indicated that gas sensors have a good potential for the rapid evaluation of oxidation catalysts. 相似文献
102.
Yasuo Takagi Mitsuru Onoda Tamotsu Toriyama Katsunori Kawasaki Toshiyuki Hattori 《亚洲传热研究》2013,42(5):444-458
This study investigated the characteristics of cell performance degradation, decline of component performance, and changes in the properties of membrane electrode assembly materials caused by repeated cold starts under a subzero condition of ?30 °C. It was made clear that functional decay appeared mainly at the cathode due to increased proton conductive impedance and reduction of reactivity of the electrode catalyst. Among the cathode components, an increase in proton conductive impedance in the cathode electrolyte was dominant. Furthermore, the application of ion chromatography and a newly developed proton‐induced gamma‐ray emission method to measure fluorine in the off‐gas drain revealed that decomposition of the electrolyte was dominant in the cathode catalyst layer. A decrease in fluorine in the cathode electrolyte measured by fluorine‐19 nuclear magnetic resonance confirmed this decomposition. A hypothesis is also presented concerning the cause of the performance degradation. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20394 相似文献
103.
A study was made to investigate an optimum condition for ruthenium tetraoxide staining of poly(butylene terephthalate) (PBT) with glass transition temperature as low as ca. 23 degrees C for TEM observation of melt-grown PBT crystals. The morphological study of ultrathin sections prepared based on optimum staining at 25 degrees C for 8 h revealed formation of fringed-micellar crystal nuclei in the early stage and folded-chain fringed-micellar crystals in the later stage of isothermal crystallization at 40 degrees C from melt. The fraction of chain-folded crystals increased with increasing crystallization temperature from the quantitative analysis of crystal thickness in comparison with the reported morphology using the replica method. 相似文献
104.
Yamamoto O Sawai J Kojima H Sasamoto T 《Journal of materials science. Materials in medicine》2002,13(8):789-792
MgO–CaO powders were prepared with different molar ratios (MgO/CaO) at 1400 °C for 2 h in air. By using the powder samples obtained, the change in bactericidal effect as a function of MgO–CaO composition was studied by colony count method. From the XRD measurements, it was found that CaO solid solution was formed by the replacement of Mg2+ ion with larger Ca2+ ion. However, no formation of MgO solid solution was observed. The average particle size and the specific surface area of the samples used in this study were about 0.2 m and 10.5m2g–1, respectively. The pH values of physiological saline containing powder samples increased with the increase of CaO content, and the value reached 12.1 in sample with the molar ratio (MgO/CaO) of 0.25. From the results of bactericidal tests for Staphylococcus aureus, it was found that the bactericidal effect increased with the increase of CaO content in the samples. 相似文献
105.
We applied a Mo/B4C multilayer coating to a laminar holographic grating with 2400 grooves/mm and a 1-m radius of curvature. By use of synchrotron soft x rays the multilayer-coated grating was evaluated to have diffraction efficiencies of 3.1% and 0.017% for s- and p-polarized radiation, respectively, at a 6.7-nm wavelength at a 45.35 degrees grazing angle of incidence in the +1 (inside) grating order. Thus the polarizance was estimated to be 98.9% at least. The zero-order peak was suppressed by the destructive interference caused by the groove profile. 相似文献
106.
Samura K Hashimoto S Kawasaki M Hayashida A Kagi E Ishiwata T Matsumi Y 《Applied optics》2002,41(12):2349-2354
Two optical methods, cavity ring-down spectroscopy and photoacoustic spectroscopy, are applied to the measurement of the isotope ratio 18O/16O in water-vapor samples with a Nd3+:YAG pumped-dye laser. The combination band of (2v1 + v3) in the 960-nm region of water molecules is investigated for two standard water samples, the Vienna Standard Mean Ocean Water and the Standard Light Antarctic Precipitation. The results demonstrate that the two methods have the potential of compact systems for in-situ measurements of H2O isotope ratio in the environment. 相似文献
107.
Tadashi Kitamura Daisuke Nishino 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(2):353-365
The design clue for the remote control of a mobile robot is inspired by the Talwar's brain-machine interface technology for remotely training and controlling rats. Our biologically inspired autonomous robot control consciousness-based architecture (CBA) is used for the remote control of a robot as a substitute for a rat. CBA is a developmental hierarchy model of the relationship between consciousness and behavior, including a training algorithm. This training algorithm computes a shortcut path to a goal using a cognitive map created based on behavior obstructions during a single successful trial. However, failures in reaching the goal due to errors of the vision and dead reckoning sensors require human intervention to improve autonomous navigation. A human operator remotely intervenes in autonomous behaviors in two ways: low-level intervention in reflexive actions and high-level ones in the cognitive map. Experiments are conducted to test CBA functions for intervention with a joystick for a Khepera robot navigating from the center of a square obstacle with an open side toward a goal. Their statistical results show that both human interventions, especially high-level ones, are effective in drastically improving the success rate of autonomous detours. 相似文献
108.
Ryosuke Ueyama Masahiro Harada Tamotu Ueyama Takashi Yamamoto Tadashi Shiosaki Kiyoshi Kuribayashi Kunihito Koumoto Won Son Seo 《Journal of Materials Science: Materials in Electronics》2000,11(2):139-143
Ultrafine BaTiO3 particles were prepared by a micro-emulsion charring (MEC) method. The MEC method consisted of two steps. The first step is the preparation of a water/oil micro-emulsion with BaTiO3 elements, and the second is a low temperature firing process in N2 atmosphere, which includes charring of oil in an emulsion and powdering BaTiO3 particles with the char. The char formed around BaTiO3 particles prevents an agglomeration of BaTiO3 particles during firing. In the present experiment, the W/O ratio and the amount of emulsifier greatly influenced the size of droplets of the emulsion. The charring temperature was another important experimental factor in order to obtain the desired BaTiO3 particles. The finally obtained BaTiO3 charring powders were monodispersed spherical particles and the particle size was 0.1 m to 0.5 m. 相似文献
109.
Production of eicosapentaenoic acid by a recombinant marine cyanobacterium, Synechococcus sp. 总被引:1,自引:0,他引:1
The eicosapentaenoic acid (EPA) synthesis gene cluster from an EPA-producing bacterium, Shewanella sp. SCRC-2738, was cloned into a broad-host range vector, pJRD215, and then introduced into a marine cyanobacterium, Synechococcus sp. NKBG15041c, by conjugation. The transconjugant cyanobacteria produced 3.7±0.2% (2.24±0.13 mg/L) EPA (n-3) and 2.5 ±0.2%
(1.49±0.06 mg/L) eicosatetraenoic acid (n-3) of the total fatty acids when the cells were cultured at 23°C at a light intensity
of 1,000–1,500 Lux. The EPA and eico-satetraenoic acid contents of the cells were increased to 4.6±0.6% (3.86±1.11 mg/L) and
4.7±0.3% (3.86±0.82 mg/L), and 7.5±0.3% (1.76±0.10 mg/L) and 5.1±0.2% (1.19±0.06 mg/L) when they were cultured at low temperature
(18°C) and at lower light intensity (40 Lux), respectively. 相似文献
110.
A. Matsubara K. Kawasaki H. Inaba S. Miyawaki O. Ishikawa T. Hata T. Kodama 《Journal of Low Temperature Physics》1999,114(3-4):349-370
We have measured the viscosity, , and the slip length, , of normal and superfluid
3
He using a torsional oscillator with a thick sample space. We coated the oscillating surface with 2.5 layers of
4
He film to study how the
4
He thin film changes the scattering mechanism of
3
He quasiparticles at the cell wall at 5 bar and 21 bar. In the normal phase, the temperature dependence of the viscosity was changed a little by the
4
He film at 21 bar but no change was observed at 5 bar. The slip length was enhanced by
4
He coating at 5 bar. This enhancement indicates the increase of specularity of
3
He quasiparticles scattering at the oscillating surface. On the other hand, a reduction of the slip length was observed at 21 bar. In the superfluid phase, the temperature dependence of supports the existence of Andreev reflection even with
4
He film on the surface at 5 bar and 21 bar. 相似文献