巻号一覧
77 巻, 4 号
選択された号の論文の8件中1～8を表示しています
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論説
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奥村 鉄平, 芝田 智樹, 大河内 敬雄2006 年 77 巻 4 号 p. 261-268
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーIt is difficult to produce titanium alloy powders with low oxygen content because of the high reactivity of molten titanium against to atmospheric gas and refractory materials. A new gas atomization process coupled with a cold crucible levitation melting and bottom tapping electric nozzle using its features as titanium melting furnace, supplies low impurities, high temperature and enough volume of molten metal, has been constructed. Thermal phenomena at bottom nozzle region, erosion resistivity of the sleeve, of which is one of the nozzle-constructed parts, to the molten titanium and atomization gas stream of this process have been revealed. Followings were found from experimental and numerical investigations. 1) Additional heat supplied by sleeve made of electrically conductive material inserted in the water cooled nozzle avoid nozzle clogging even for small radius nozzle. 2) Tungsten showed lowest erosion rate among the candidate materials for sleeve. 3) Conically enclosed space by atomizing gas induces unfavorable gas flow and low pressure region. Developed atomization system, electric bottom tapping nozzle and pencil nozzle for atomization, that is designed based on above results showed following features. 1) Tapping and atomization were stable and were continuously done without changing or repairing nozzle part. 2) Atomization yield was increased since the reuse of bottom skull was enabling. 3) This process allows the production of fine (d50=85μm) Ti-6Al-4V alloy powders.抄録全体を表示PDF形式でダウンロード (458K) -
藤田 雄一郎, 高木 忍, 清水 孝純, 井上 明久2006 年 77 巻 4 号 p. 269-276
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーNi-Nb-Ti-Zr glassy alloys were developed as separator plates for polymer electrolyte fuel cell. Results are summarized as follows. Higher Nb containing Ni-Nb-Ti-Zr glassy alloys show better corrosion resistance in sulfuric acid. Corrosion rate of the Ni-15Nb-15Ti-10Zr glassy alloy was three orders of magnitude lower than that of SUS316L steel. Ultra-thin separator sheets with flow channels could be formed precisely by hot pressing the Ni-15Nb-15Ti-10Zr glassy metal strip by hot pressing near the glass transition temperature without crystallization. Single cell with Ni-15Nb-15Ti-10Zr glassy metal separator plates show higer cell voltage than that with SUS316L separator plates, because of lower cell resitance. In the 1080 ks operating test, the voltage drop rate was also equivalent to the graphite separator plates.抄録全体を表示PDF形式でダウンロード (517K) -
本間 大, 中澤 文雄2006 年 77 巻 4 号 p. 277-283
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーThe crystal grains rotate and slip, maintaining a state of equigranular crystal, in the process of super plasticity deformation. The functional anisotropic Ti-Ni-Cu shape memory alloy fiber was developed, in which this property of super plasticity was applied to trim the direction of fine grains for the designed motion. An idea to use super plasticity in order to derive the property of poly-crystal function materials is rare till now. The method is supposed to provides a way to operate the grain boundary that is a domain of micro or nano meter order directly. The application to other materials except SMA can be expected enough. The characteristics of the material and the result of application are as follows. 1. The material has a two directional shape memory effect of approx. 5 % tensile strain. 2. It is easy to design shape memory alloy actuators with its wide operational range of low stress and large strain. 3. The fiber of the material performed more than 8×108 times reciprocated elongation and contraction of 3 % tensile strain and 100 MPa stress. 4. A servo actuator can be easily made. The servo actuator uses the approximately linear stable electric resistance variation of the material corresponding to a shape-memory effect as a position sensor.抄録全体を表示PDF形式でダウンロード (487K) -
齊藤 貴伸, 武本 聡2006 年 77 巻 4 号 p. 285-291
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーCompressed cores made with Fe-Si alloys are expected for smoothing and boost choke coils of switching regulators and DC-DC converters. In this study, compressed cores were made with atomized Fe-3mass%Si, and the relationships between particle size, crystal grain size and core loss were investigated. The crystal grain sizes were changed by heat treatment temperature. The following conclusions were obtained. (1) Hysteresis loss decreases with increase in crystal grain size. (2) Both contributions of classical eddy current loss assuming uniform magnetization and localized eddy current loss by domain wall movements were confirmed. It was found that anomalous eddy current loss is proportional to square root of the crystal grain size. As particle size decreases, anomalous eddy current loss becomes dominant relative to classical eddy current loss, because classical eddy current loss decreases.抄録全体を表示PDF形式でダウンロード (396K)
解説
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中山 浩, 堀 美知郎2006 年 77 巻 4 号 p. 293-300
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーFuel cell technology offers an attractive combination of highly efficient fuel utilization and environmentally-friendly operations. In the past decade, fuel cell system has been greatly developed and some products with fuel cell have already introduced to a market. In this paper, we mainly introduce the characteristics of Polymer Electrolyte Fuel Cell (PEFC) and Direct Methanol Fuel Cell (DMFC), and the recent advances of domestic and foreign PEFC system at portable, stationary, and fuel cell vehicle (FCV) applications. In addition, the governmental scenario for wider commercialization and the present technical problems such as initial cost and energy conversion efficiency are discussed.抄録全体を表示PDF形式でダウンロード (453K) -
境 哲男2006 年 77 巻 4 号 p. 301-309
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーAlloy-based negative electrode materials have much higher specific capacity per weight and per volume than a conventional graphite-based material, but show very short cycle lives due to a large volume change during Li charge-discharge cycles. Tin based nano-composite alloys (Sn/Ag3Sn) prepared by mechanical alloying method showed significantly improved cycle life because structure and phase changes could occur easily via intermediated ternary phases LiAg2Sn/Li2AgSn during charge-discharge process. Tin-based multi-layered plated electrodes (Sn/Cu6 Sn5 /Zn) prepared by electrochemical plating method also showed much improved cycle life. Silicon-based nano-composite films (Si/Ni,Cr,Nb,Fe) were also developed with improved cycle life. Nano-designing of materials would be very important for improving the cycle lives, keeping the high capacity.抄録全体を表示PDF形式でダウンロード (547K) -
新藤 裕一朗2006 年 77 巻 4 号 p. 311-320
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーUltra high purity materials have developed with the semiconductor material. Furthermore, these materials have attractive characteristics to conventional materials. Ultra high purity materials have been obtained high electrical and thermal conductivity at low temperature, lower hardness, lower softening temperature, lower deformation resistance (high workability), higher Residual Resistivity Ratios (RRR) due to less non-metallic inclusion and voids. These properties have not been recognized in the conventional materials. Ultra high purity materials have been expected to be useful for semiconductor application, MoSi2 heater, freezing point measurement, analysis standard sample, high temperature application, bonding wire and so on.抄録全体を表示PDF形式でダウンロード (634K)
技術資料
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高木 忍2006 年 77 巻 4 号 p. 321-326
発行日: 2006/12/21
公開日: 2007/06/21
ジャーナル フリーDaido Steel Co.,Ltd. has developed a new metallic material "NANOCLAD" for PEFC (Polymer Electrolyte Fuel Cell) separators. With an extremely thin layer of gold on the specially formulated stainless steel sheets, "NANOCLAD" has the highest level of corrosion resistance and electrical conductivity among metal separator materials currently available. The fuel cells using "NANOCLAD" have been tested for 3000 hours and exhibited the same or higher power generation performance than the cells with conventional carbon separators. PEFC with metallic separators are expected to be used for fuel cell vehicles, combined heat and power systems for homes and businesses, and power supplies for portable devices which would replace lithium ion batteries and they will play a key role in the widespread commercialization of fuel cells.抄録全体を表示PDF形式でダウンロード (453K)
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