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排序方式: 共有509条查询结果,搜索用时 15 毫秒
21.
Satoshi Suzuki Mari Fukuoka Hikaru Ookuchi Motoaki Sano Kenji Ozeki Emi Nagayoshi Yukio Takii Mayumi Matsushita Sawaki Tada Ken-Ichi Kusumoto Yutaka Kashiwagi 《Journal of Bioscience and Bioengineering》2010,109(2):115-117
This is the first report of glycoside hydrolase family 43 β-xylosidase from Aspergillus oryzae. To characterize this enzyme, the recombinant enzyme was expressed in Escherichia coli. Unlike known β-xylosidases from fungal origins, the enzyme did not show substrate ambiguity and was stable at alkaline pH. 相似文献
22.
Sodium niobate NaNbO3 hydrate (NN‐hydrate) particles with a plate‐like morphology were prepared at 140°C for 2 h in 12 mol/L of NaOH by the hydrothermal method. Bar‐like Na8Nb6O19·13H2O particles were synthesized at as low as 100°C for 2 h. This work demonstrates that by carefully optimizing the reaction condition, we can selectively fabricate niobate structures, including the bar‐like, plate‐like, fibers and cube particles through a direct reaction between NaOH solution and Nb2O5. It was found that Nb6O198? formed was an important premise for formation of the NN‐hydrate, and lower [OH–] was not favorable in preparing the NN‐hydrate as there was an optimum [OH?]. Through researching effects of the reaction temperature, time, concentration of NaOH, and content of Nb2O5 on the NN‐hydrate structure and evolution, the formation mechanism from solid reactants to the intermediate were investigated. After calcining at 800°C, the synthesized NN‐hydrate particles made a phase almost transform to the perovskite NaNbO3, and the morphology of these calcined particles was still plate‐like. 相似文献
23.
Recovery of liquid fuel from hydrocarbon-rich microalgae by thermochemical liquefaction 总被引:11,自引:0,他引:11
Yutaka Dote Shigeki Sawayama Seiichi Inoue Tomoaki Minowa Shin-ya Yokoyama 《Fuel》1994,73(12):1855-1857
Liquefaction of Botryococcus braunii, a colony-forming microalga, with high moisture content was performed with or without sodium carbonate as a catalyst for conversion into liquid fuel and recovery of hydrocarbons. A greater amount of oil than the content of hydrocarbons in B. braunii (50 wt% db) was obtained, in a yield of 57–64 wt% at 300 °C. The oil was equivalent in quality to petroleum oil. The recovery of hydrocarbons was a maximum (>95%) at 300 °C. 相似文献
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26.
Highly efficient power coupling of up to 97% between a d.h. laser and a multimode step-index fibre is demonstrated by employing a tapered fibre launcher. Also, it is shown theoretically that a tapered end increases the effective numerical aperture of a fibre. For a Lambertian emitter, the use of a taper launcher permits the maximum coupling efficiency allowed by the Liouville theorem. 相似文献
27.
We have developed the separated pulsed laser deposition (SPLD) technique to prepare high quality ZnO based films exhibiting uniform and droplet-free properties. This SPLD consists of an ablation chamber and a deposition chamber which can be independently evacuated under different ambient gases.The gas species and the pressures in both chambers can be arbitrarily chosen for the specific deposition such as nanostructured films and nanoparticles. The ablation chamber is a stainless steel globe and the deposition chamber is a quartz tube connected to a metallic conic wall with an orifice. We used a KrF excimer laser with λ = 248 nm and 25 ns pulse duration. The different gas conditions in two chambers allow us to realize optimal control of the plasma plume, the gas phase reaction and the film growth by applying the bias voltage between the conic wall and the substrate under the magnetic field. We can expect that at appropriate pressures the electric and magnetic field motion (E × B azimuthal drift velocity) gives significant influences on film growth.We have deposited ZnO thin films at various pressures of ablation chamber (Pab) and deposition chamber (Pd). The deposition conditions used here were laser fluence of 3 J/cm2, laser shot number of 30,000, Pab of 0.67-2.67 Pa (O2 or Ar), Pd of 0.399-2.67 Pa (O2), and substrate temperature of 400 °C. Particle-free and uniform ZnO films were obtained at Pab of 0.67 Pa (Ar) and Pd of 1.33 Pa (O2). The ZnO film showed high preferential orientation of (002) plane, optical band gap of 2.7 eV, grain size of 42 nm and surface roughness of 1.2 nm. 相似文献
28.
Kanichi Kamiya Tomoaki Nishijima Katsuhisa Tanaka 《Journal of the American Ceramic Society》1990,73(9):2750-2752
Dip-coated sol–gel-derived TiO2 films on an alumina substrate were converted to nonstoichiometric titanium nitride (TiN x ( x ≦ 1)) films by heating at approxmately 1000°C in NH3 gas. TiO2 films made from TiO2 sols prepared from Ti(O– i -C3 H7 )4 and stabilized by diethanolamine were more easily nitrided than those from sols containing HCl as a deflocculant reagent. This appears to be a result of the more porous structure of the former films. 相似文献
29.
A. Takenaka Y. Ozeki S. Hiraki M. Hattori I. Motooka H. Nariai 《Journal of Materials Science》1996,31(24):6511-6513
The intercalation reaction of n-alkylamines from methyl- to hexadecylamine into -tin(IV) bis(hydrogenphosphate) has been investigated. The reaction was conducted by mixing the phosphate and solutions of the amines dissolved in water or benzene. The amine/ phosphate molar ratios in the reaction mixtures were 0.43, 0.85, 1.71 and 3.41. The nitrogen/phosphorus atomic ratio in the intercalation compound was not changed by the amine/phosphate molar ratio. The interlayer distances of the intercalates obtained in the reaction mixtures with molar ratios of 3.41 and 1.71 increased with an increase in the number of carbon atoms in the alkyl chain of the amine. The slope of the straight line obtained in plot of interlayer distance versus number of carbon atoms in the alkyl chain of the amine indicates that the amine molecules form a double layer in the interlayer space of the phosphate and are inclined at an approximate angle of 67.7° to the phosphate layer. The interlayer distances of the intercalates of butyl- to nonylamines obtained at the molar ratio of 0.85 are smaller than those of the corresponding compounds from the molar ratios of 3.41 and 1.71, while those of decyl- to hexadecylamine intercalates lie on the previously discussed line. This behaviour is interpreted by assuming kink formation in the short alkyl chains between the phosphate layers. 相似文献
30.
由于大部分的生物体都具有相对的自发性、功能性和有效率性,模仿生物体动作的机械研究在工程领域是非常重要的。根据这个观点,我们研究了一种基于水中微生物动作的微型推进机构。 相似文献