巻号一覧
79 巻, 2 号
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染川 英俊, 大澤 嘉昭, シン アロック, 鷲尾 宏太, 加藤 晃, 向井 敏司2015 年 79 巻 2 号 p. 35-40
発行日: 2015年
公開日: 2015/02/01
ジャーナル フリーThe effect of minor yttrium atom addition on deformation behavior was investigated using Mg-X at%Y (X=0.01, 0.02, 0.03, 0.04 and 0.05) dilute alloys and pure magnesium with an average grain size of about 50 μm. The stress and strain curves in all the alloys showed a sigmoidal shape in the compression tests, which suggested the formation of {1012}-type twinning due to the lack of slip system. On the other hand, yttrium atom addition of more than 0.03 at% was effective to affect the deformation behavior: a large compressive strain of 0.5 was possible to obtain, and the sub-grained and fine-grained structures were formed even at room temperature in three kinds of alloys. The dominant deformation mechanism in these alloys was the twinning at the beginning of the state and the dislocation slip with further imposed strain.
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吉村 彰大, 梅原 佳那, 高井 まどか, 松野 泰也2015 年 79 巻 2 号 p. 41-48
発行日: 2015年
公開日: 2015/02/01
ジャーナル フリーWe have presented a novel process for recycling gold from secondary sources: Leaching of gold by dimethyl sulfoxide solutions containing copper bromide and precipitation with water, which could offer a number of advantages, including eco-friendliness, ease of operation and low cost. In this work, we applied this process to other metals which are contained in secondary sources, e.g. printed wired board. The mechanism of dissolution was investigated by electrochemical measurements. Metal wires were dissolved in a DMSO solution with 0.2 M of CuBr2 and 0.2 M of KBr at 343 K. The precipitation of dissolved metals were performed by the addition of water, during which the effects of the amount of water and pH on the recovery rate were investigated. The results of the electrochemical measurements indicate that the anodic dissolution of sample metals in DMSO containing CuBr2 occurs at relatively negative potentials and is paired with the cathodic reduction of Cu2+ to Cu+. It was found that gold, silver, copper, tin, cobalt, nickel and zinc were able to be dissolved, all of which can be effectively precipitated by the addition of water with appropriate pH.
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根本 圭一, 菊川 久夫, 森山 裕幸, 粕谷 平和2015 年 79 巻 2 号 p. 49-56
発行日: 2015年
公開日: 2015/02/01
ジャーナル フリーAdvanced fiber-reinforced composite materials are used as structural members in various fields because of their high strength and high stiffness-to-weight ratios, and hence analysis of thin laminated structures is important. Post-buckling behaviors of thin laminated plates under uniaxial compression have been discussed by many researchers. However, little research has been performed on the secondary buckling phenomenon for thin laminated plate which occurs with further increase of load. In this paper, the stability condition of carbon-epoxy symmetrically laminated plates with initial deflections under uniaxial compression which are simply supported along four edges is determined, using the second variation of total potential energy. The necessity of secondary buckling is proven analytically, and the effects of various factors, such as initial deflection, lamination constitution, and number of layers, are clarified.
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桐野 文良, 北田 正弘2015 年 79 巻 2 号 p. 57-63
発行日: 2015年
公開日: 2015/02/01
ジャーナル フリーThe microstructures of a corrosion layer formed on the surface of two Japanese oldest coins, Wadoukaichin (surface color: dark brown and green) were studied. Compositions of these coins are that main element is Cu and Sn and traces are Pb, Fe and As. X-ray diffraction patterns show that copper di-hydroxide (Cu(OH)2 2H2O), Cu1.81S and Cu2O are detected on the surface corrosion layer of dark brown sample, and Cu2(CO3)(OH)2 (malachite), Cu3(CO3)2(OH)2 (azurite) and Cu2O are detected on the surface corrosion layer of green sample. Optical microscope images show that the surface corrosion layer of dark brown sample is porous, and blue and green grains on the brown layer are existed on that of green sample. From spectrographs of these grains, the peak wavelength of green grains is matched to that of malachite, but this of blue grains is shifted to long wavelength side of about 40 nm at azurite on an influence of trace contaminations. The corrosion layer has two layers, surface layer is plate-like texture, and under layer is aggregation microstructure from TEM observation. The crystal structure of these two layers is matched to azurite from the electron beam diffraction patterns.
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北田 正弘, 高妻 洋成, 肥塚 隆保, 建石 徹2015 年 79 巻 2 号 p. 64-70
発行日: 2015年
公開日: 2015/02/01
ジャーナル フリーThe Takamatsuzuka tumulus was constructed in the 7-8th centuries at Asuka in Nara prefecture (the Kinki region in Japan). The tumulus was excavated by village Asuka proprietor in 1972 and a beautiful mural of human figures and other subjects were discovered. However, the mural is deteriorating as a result of rainwater, mold, and other unknown causes. The purpose of this investigation is to clarify the composition, crystal structure, and other material factors of the red pigment layer of the mural as basic research to identify the materials used in the mural. An optical microscope, a scanning electron microscope, and a transmission electron microscope are utilized to examine the microstructure. The red particles on the white stucco base are observed with the optical microscope. Mercury and sulfur are detected from the red pigment by EDS, and hexagonal HgS is confirmed by electron diffraction pattern analysis. Therefore, the red pigment is cinnabar (HgS). The HgS particle size is 0.2 to 5 μm and the surface is in a cloven condition. This shows that the particles have been crushed mechanically. Calcite and albite exist as the base matter and impurity particle, respectively.
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北田 正弘, 高妻 洋成, 肥塚 隆保, 建石 徹2015 年 79 巻 2 号 p. 71-75
発行日: 2015年
公開日: 2015/02/01
ジャーナル フリーThe mural of the Takamatsuzuka tumulus in Asuka, Nara prefecture, was painted in the 7-8th centuries. Red, green, blue, yellow, and black pigments are used in the mural. The microstructure of one of them, the red pigment, was described in the previous paper. In this study, the black pigment observed within the red pigment area has been investigated. An optical microscope, a scanning electron microscope, and a transmission electron microscope are utilized to examine the microstructure. Among the black particles, two different Fe compounds are observed. One is magnetite (Fe3O4) comprising small amounts of Ti, Al, and Mg, and the other is ilmenite (FeTiO3) containing a small amount of Mg. In addition to the above compounds, an oxide particle containing Zr is also observed.
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