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排序方式: 共有1455条查询结果,搜索用时 578 毫秒
51.
Md Tasyrif Abdul Rahman Nobuyuki KawaharaKazuya Tsuboi Eiji Tomita 《International Journal of Hydrogen Energy》2014
In this work, spark-induced breakdown spectroscopy (SIBS) was employed to investigate the mixing process of a hydrogen jet in a constant-volume vessel. The local fuel concentration of the hydrogen jet was measured at several locations, using a SIBS sensor. A high-speed camera was used to visualize spark discharge fluctuations, and hydrogen jet concentration measurements were conducted simultaneously. Spectrally resolved atomic emissions from the plasma generated by the spark plug were examined to determine the local equivalence ratio. Direct visualization of the spark discharge provided useful information about the influence of spark discharge characteristics related to the spark timing. Using the developed SIBS sensor, atomic emission spectra were obtained from hydrogen Hα at 656 nm and nitrogen N (I) at 501 nm. Comparison of the intensity peaks of atomic emissions from hydrogen and nitrogen allows the local hydrogen concentration in a measured volume to be determined, and hence also the local equivalence ratio. The measurement results demonstrate the local variation in the equivalence ratio throughout the jet and along its axis. From the results, the spatial structure of the hydrogen jet affects the hydrogen/nitrogen mixing and could be clarified with SIBS technique when the spark is discharged. 相似文献
52.
Katsuhiro Inomata Tamiko Terahama Rena Sekoguchi Tatsunori Ito Hideki Sugimoto Eiji Nakanishi 《Polymer》2012,53(15):3281-3286
Polypeptide hydrogels were prepared by cross-linking of hydrophobically-modified poly[N5-(2-hydroxyethyl) l-glutamine] having alkyl side chains –CnH2n+1. Chain length of the alkyl group was n = 8, 16, and 18, and their mole fractions in the polypeptide were varied in the range of 0.05–0.16. Shape memory ability of the prepared polypeptide hydrogels was investigated. After deformation at 60 °C, the hydrogel was cooled in order to fix the temporary deformed shape. It was found that crystallization of the alkyl side chains did not occur, and the fixation ability of the hydrogel at 0 °C was low. In the subsequent heating process, the deformed temporary shape spontaneously recovered to the original shape gradually with increasing temperature, in other words, the shape recovery ratio varied with depending on the recovery temperature. From these observations, it was proposed that the shape fixation of the polypeptide hydrogel was achieved by strong segregation of the hydrophobic alkyl chains at low temperature, and the shape recovery of the deformed hydrogel was accompanied by the gradual decrease of the segregation strength with the temperature increase. 相似文献
53.
Hydrogenases catalyze uptake and production of H2. Heterolytic cleavage of H2 bound on [NiFe]-hydrogenase (E) produces two unequal H species to form E:HaHb, where Ha and Hb behave differently. The structures of various states of the enzyme established by crystallography and spectroscopy were used to construct a catalytic cycle of the enzyme. The Ni–Fe center of the active enzyme has the Ni–Fe bridging site vacant. The enzyme is suggested to bind H2 either at Ni or Fe atom. In E:HaHb, Ha is considered to be a protein-bound hydron (proton or deuteron) at the entrance to the hydrophobic gas tunnel. The structure of a synthetic hydrogenase-mimic suggests Hb to be the 6th ligand to Fe. Two successive one-electron processes from E:HaHb complete the catalytic cycle of H2 uptake. The reverse of the cycle operates in the H2 production. The proposed catalytic cycle is consistent with the kinetic, crystallographic and spectroscopic studies. 相似文献
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55.
Masao Shibuya Motoshi Kato Masaki Ozawa P. H. Fang Eiji Ōsawa 《Fullerenes, Nanotubes and Carbon Nanostructures》2013,21(2):181-193
Abstract It was confirmed that soot produced by free burning of small hydrocarbons like benzene and cyclohexane generally contains less than 0.1 ppm of C60. Small, but measurable amounts of C60 were found in two samples of charcoal, providing the first indication of fullerene formation in the solid state. 相似文献
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57.
Kotaro Matsushita Shun Koshikawa Taito Endoh Jong G. Park Takashi Yamaguchi Kennth J. Mackin Eiji Nunohiro 《Artificial Life and Robotics》2014,19(3):258-261
It is important for environment protection to monitor changes in the environment by natural and human causes. It is also important to educate the next generation on the importance of the global environment issues. Recently, it has become possible to continually monitor the global environment using various satellite sensor data. But these satellite data are used for highly specialized analysis by experts in such fields, and the data cannot easily be used by non-experts. In this paper, we propose a satellite data visualization system for educational use. In the proposed system, a gray-scale 2-dimensional image is created from the satellite data. Next, a pseudo-color image is created from the gray-scale image to assist the comprehension of the data. A 3-dimensional data representation of the image is also created, to assist the comparison of the individual data. The aim of the created image is for educational use, and the image is created with emphasis on comprehension of the data, rather than presentation of data details. The aim of the proposed system is presenting the satellite data visually so that non-experts can easily understand. The target of this research is to apply the proposed system for natural science education and to improve the awareness of global environmental issues. 相似文献
58.
Research and Development of the Coprecipitation Process for Lanthanum Germanate Oxyapatite 下载免费PDF全文
Kiyoshi Kobayashi Shouta Kitajima Yukihito Igarashi Tohru Higuchi Yoshio Sakka 《Journal of the American Ceramic Society》2015,98(1):66-70
Although lanthanum germanate oxyapatite (La–Ge–O) has shown good potential for use as a solid electrolyte in energy storage applications, its synthesis has been challenging by either solid‐ or solution‐state methods. In this study, a new synthesis of La–Ge–O was developed through a coprecipitation technique, in which a highly concentrated homogeneous aqueous solution of La and Ge was prepared from aqueous ammonium germanate and lanthanum nitrate solutions with the addition of dilute nitric acid. Several precipitates were formed by pH manipulation, including an amorphous material obtained at pH > 3. Compared to the individual precipitation behaviors of the parent compounds, the amorphous precipitate was formed only from the aqueous two‐component mixture, and appeared to contain both metals. This material was transformed into crystalline mixtures upon heating at 1273 K. The crystalline phases were La2Ge3O9 and hexagonal‐type GeO2 when the precipitate was formed below pH 8, and the La–Ge–O and La2Ge2O7 phases when the precipitate was formed around pH 8. Product formation from the coprecipitate was discussed based on X‐ray diffraction and thermal analyses. The improved availability of La–Ge–O will allow more extensive investigations of its useful properties. 相似文献
59.
Satoshi?KameokaEmail author Satoru?Wakabayashi Eiji?Abe An?Pang?Tsai 《Catalysis Letters》2016,146(7):1309-1316
60.