巻号一覧
45 巻, 2 号
選択された号の論文の17件中1～17を表示しています
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一ノ瀬 昇1998 年 45 巻 2 号 p. 108
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーPDF形式でダウンロード (75K) -
塩原 融1998 年 45 巻 2 号 p. 109-113
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーSingle crystal growth and solidification processing of Nd- 123 superconductive oxides are reviewed in comparison with Y-123 oxide. Since Nd-123 crystal forms a solid solution due to Nd/Ba substitution, this crystal is considered to be nonstoichiometric while Y-123 is a stoichiometric compound at least for its cation constituents. Crystal growth processing of nonstoichiometric compounds (Nd-123) with homogeneous composition distribution should be different from that of stoichiometric (Y-123) compounds, because the former case is one degree of freedom in the Gibbs phase rule higher than the latter case. In this paper, difference in crystal growth mechanisms between Nd-123 and Y-123 is discussed, taking into consideration of equilibrium phase diagrams, kinetics of the 123 phase crystal growth.抄録全体を表示PDF形式でダウンロード (1604K) -
山田 高広, 新苗 稔展, 池田 靖訓, 広井 善二, 高野 幹夫, 坂東 尚周1998 年 45 巻 2 号 p. 114-118
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーSubsolidus phase diagram of the NdO1.5-SrO-CuO system was studied at 980°C and 1080°C in Air. One ternary compound Sr1.08Nd1.92Cu2O6-δ, and three solid solutions exist; Sr14-xNdxCu24O41+δ, (0 ?? x ?? 6.0 at 980°C), Sr2-xNd1+xCu2O5.5+δ(0.05 ?? x ?? 0.20 at 980°C; 0.05 ?? x ?? 0.35 at 1080°C), and Sr2-xNdxCuO3+δ (x=2/3 at 980°C; 0.5 ?? x ?? 0.95 at 1080°C).Sr2-xNdxCuO3+δ which crystallizes in the oxygen deficient K2NiF4 structure shows a unique modulated structure, The origin of the modulated structure is suggested to be a large lattice mismatch between the (Sr, Nd)2O2 and the CuO1+δ layer.抄録全体を表示PDF形式でダウンロード (1562K) -
小林 斉也, 広井 善二, 高野 幹夫1998 年 45 巻 2 号 p. 119-124
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーWe have studied the effects of partial substitution of La for Y and Sc in two-leg ladder compound LaCuO2.5 synthesized under high pressure by using XRD-Rietveld structural refinements and magnetic susceptibility measurements. The antiferro-magnetic transition temperature(TN) of LaCuO2.5 is 120 K, and is increased to-300 K for the Y substitution, while the Sc substitution reduces TN to-15 K. These substitutions can control the interladder interaction by changing the Cu-O-Cu bond angle bridging two adjacent ladders.抄録全体を表示PDF形式でダウンロード (430K) -
杉俣 悦郎, 大橋 憲太郎, 那須 昭一1998 年 45 巻 2 号 p. 125-128
発行日: 1998/02/15
公開日: 2010/07/12
ジャーナル フリーWe experimented with investigation of the model of electrochemical reduction in electrochemical treatment on Bi2Sr2CaCu2OY superconductor by using methyl alcohol as solvent and three materials: Ca(NO3)2⋅4H2O, CuSO4⋅5H2O and Cu(NO3)2⋅3H2O as solutes. The samples before and after the treatment were investigaited by X-ray diffraction, fluorescent X-ray analysis and resistivity measurement.
As a result, we suggested two model of reduction such as
(1)Bi2Sr2CaCu2O8+ (x+y)Ca2++ 2(x+y)e-→Bi2Sr2Ca1+xCu2O8+ yCa
(2)Bi2Sr2CaCu2O8+ (x+y)Cu2++ 2(x+y)e-→ Bi2Sr2CaCu2+XO8+ yCu
where (x+y) is constant in each quantity of electricity and y is much greater than x. However x and y were so randomly variable that it was very difficult to control of electrochemical reduction.抄録全体を表示PDF形式でダウンロード (307K) -
低温生成機構の検討菊池 丈幸, 藤原 正志, 長江 正寛, 草野 圭弘, 中西 真, 高田 潤1998 年 45 巻 2 号 p. 129-134
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーEffects of Li-addition on the formation process of Bi-2212 phase have been studied for samples with a nominal composition of Bi:Sr:Ca:Cu:Li=2:1.5:1.5:2:0.2. Samples were heated at temperatures ranging between 560°C and 730°C in air with various heating rates. The formation range of the phases formed was determined by powder X-ray diffraction method(XRD). Li-addition seems to bring two different effects on the formation process of the Bi-2212 phase: an acceleration of the formation of Bi-2201 phase on heating and early stage of holding at 730°C, and a promotion of phase transformation of Bi-2201 phase to Bi-2212 phase after holding for a few hours. Such two effects can be explained by formation of two different oxides which were newly found. The microstructures of the newly found oxides were observed by scanning electron microscopy(SEM), high-resolution transmission electron microscopy(HR-TEM) and electron diffraction(ED).抄録全体を表示PDF形式でダウンロード (3159K) -
Shinjiro Tochihara, Ken-ichiro Harashima, Yasuoka Hiroshi, Hiromasa Ma ...1998 年 45 巻 2 号 p. 135-139
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーTo test the utility of the modified Kim-Anderson critical-state model for study of the magnetic response of ceramic superconductors, we measured the initial magnetization, hysteresis loops and ac complex susceptibilities Xn=X'n-iX"n(n =1, 2, 3, 5) of a single-crystal Bi2Sr2CaCu2O8+d bulk sample. The results were simulated in the framework of the model. Analyses of Xn have shown that generation of the higher harmonics can be qualitatively reproduced, where the material parameters k and B0, surface barriers ΔH and lower critical fields Hcl, involved were used as fitting parameters. Comparison of the observed data with the calculated results has revealed that nonzero values of Hcl, play an essential role in the magnetic characteristics of the sample.抄録全体を表示PDF形式でダウンロード (275K) -
堀田 勝喜, 宮沢 肇, 宮澤 義典, 廣瀬 治男1998 年 45 巻 2 号 p. 140-144
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーProduction of oxide superconductors requires heat treatment which limits size of maximum superconductive area depending on the capacity of the electric furnace. A study on connecting superconductors was conducted to obtain large area superconductors such as for magnetic shield. A combination of two pieces of same superconductors with a pasted medium of the identical phase powder at their joint portion were installed on a jig system settled on an X-Y table to be exposed to laser irradiation. Two kinds of Bi system samples i.e., one is 2212 phase thick film prepared on MgO substrate and one is 2223 phase sintered bulk were used as starting materials respectively. A CO2 laser beam accompanied by oxygen gas blow was irradiated onto the medium along the contact line at the fixed defocus distance of 120mm under the conditions: laser output power 180-500W, assist gas pressure 98-194kPa, beam scan speed 2-10mm/min and beam scan times 4-7strokes. The laser irradiation onto the 2223 phase medium was conducted both top and bottom surfaces. As a result, Tc(end) of 60.6K and 77.3K was obtained for 2212 phase and 2223 respectively after laser irradiation.抄録全体を表示PDF形式でダウンロード (1960K) -
花崎 伸作, 藤原 順介, 和田 任弘1998 年 45 巻 2 号 p. 147-152
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーIn turning of steels, continuous chips are occurred easily. In this case, a chip breaker is usually used for breaking of continuous chips. However, in high speed turning under finishing conditions, low feed rate and small depth of cut, continuous chips are not able to be broken easily. Then, a new chip breaker was designed in order to find out a more effective chip breaker than the commercial chip breaker in turning. A circular cylinder of SS400 was turned by the tool with this chip breaker. And then, circular cylinders of the other steels i.e. SCM440, SUS304, S55C, SK5 were further turned by the tool with this chip breaker. It was found that this chip breaker was almost effective to five kinds of steel i.e. SS400, SCM440, SUS304, S55C, SK5. However, there is a little differences in the configuration of the chip obtained in turning between SS400 and SCM440, SUS304, S55C or SK5. There seems to be a possibility of some other chip braking mechanism existing in turning of SCM440 etc.. So, in turning of four kinds of steel i.e. SCM440, SUS304, S55C, SK5 by the tool with this chip breaker, the mechanism of chip breaking was investigated. And then, the effective part for the chip breaking on this chip breaker is investigated in order to design a new chip breaker applicable to wide range of the cutting conditions. The mode of the chip breaking is divided into seven types. Each part of this chip breaker has an effect on these types of chip breaking.抄録全体を表示PDF形式でダウンロード (416K) -
鷲見 新一, 水谷 芳樹, 米谷 道夫1998 年 45 巻 2 号 p. 153-157
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーThe plasma activated sintering (PAS) is a kind of hot pressing method. During pressing, the electric current flows in the mold (die and punches) and powder sample. There are two types of electric current. The surface of the powder is cleaned and activated by activating electric current. The mold and powder sample is heated by sintering electric current due to the Joule effect. It is well-known that the temperature of a sample is closely related to the sintered materials' properties and there is a favored temperature for sintering the powder. The temperature is measured either by thermocouples in the mold or by an infrared optical thermometer focused on the mold surface, but these measurements do not give the temperature of the sample in the mold itself. Sometimes the real temperature of samples is higher than the measured temperature. This temperature difference depends on the material properties, especially the electric resistance and the thickness of the sample. The authors studied experimentally the relation between the temperature difference and the electric resistance using dummy samples made of stainless steel, graphite and alumina.抄録全体を表示PDF形式でダウンロード (415K) -
国枝 義彦, 中井 善男, 井上 哲雄, 兼松 秀行, 下古谷 博司, 江崎 尚和1998 年 45 巻 2 号 p. 158-162
発行日: 1998/02/15
公開日: 2010/07/12
ジャーナル フリーThe sintered porous Ni is very important as electrode materials and have been used widely. Then, in this work, the effect of the surrounding pressure under capsule-free HIP (CFHIP), vacuum sinterings on the hardness of the porous Ni compact sintered at 1073K, 1173K and 1273K for 1 hour was investigated. The results obtained were as follows. The volume shrinkage of the porous Ni compact sintered in CFHIP was lager than that of ones sintered in vacuum. The hardness of the porous Ni compact sintered in CFHIP was larger than in vacuum. The hardness of the sintered porous Ni compact formed from the smaller particle size powder was higher under the both surrouding pressures, CFHIP or vacuum, and at the each sintering temperature.抄録全体を表示PDF形式でダウンロード (4071K) -
愼田 顕, 山下 治, 伊藤 崇, 高橋 朝彦1998 年 45 巻 2 号 p. 163-168
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーA process to obtain the anisotropic spray dried Nd-Fe-B powder has been studied in order to improve the poor alignment of sintered magnets synthesized by the usual isotropic spray dried powder. A magnetic field of 0.12 MA/m was applied transversely to the flow of droplet where it dried up to be granulated powder which has a good flowability. The measurement of the initial magnetization curve and the X-ray diffraction patterns revealed that the easy axis of powders aligns to the direction of the external field more easily compared with the isotropic powder
spray dried in the same condition without a magnetic field. It suggests that our spray dried powder is anisoptropic; Nd-Fe-B fine powder included in each granular is uniaxially aligned. The alignment of the anisotropic spray dried powder in a low field is dominated by the rotation of granulated powder. When the strength of the magnetic field at compacting is 0.23 MA/m, (BH)max of the sintered magnet obtained from the anisotropic spray dried powder exceeds by 19.2 % than the value for the isotropic one.抄録全体を表示PDF形式でダウンロード (4009K) -
長柄 毅一, 横田 勝, 野瀬 正照1998 年 45 巻 2 号 p. 169-171
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーThe ceramics(h-BN) core was applied for the Pulse Discharge Pressure Sintering (PDPS) method in order to consolidate the hollow shaped compact of the aluminum alloy powder(A 2014) and nickel alloy powder(Alloy 625).
The densities of these compacts were 2.78 g/cm3 and 8.41 g/cm3, respectively. These values correspond to the densities of solid compacts which were sintered by PDPS without using the ceramic core.
This method can be applied for the consolidation of complicated shape hollow compact like gear, tools etc, .抄録全体を表示PDF形式でダウンロード (1749K) -
仕上げ面粗さと曲げ強さ千徳 英一, 田中 大, 河端 裕1998 年 45 巻 2 号 p. 172-175
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーIn recent years, many ceramics have been developed for the uses for mechanical or electronic parts. The high strength ceramics is necessary for the world of engineering materials. The cutting of the alumina green compact was carried out by a lathe with the condition of the cutting speed 100m/min. The purpose of the study is to clarify relation between surface roughness on the surface of green compact and bending strength of the ceramics. The bending experiment on the ceramics is discussed and then bending strength and the fracture energy were investigated. The main results obtained are as follows; (1) The true bending strength of the alumina ceramics is affected by the surface roughness of the alumina green compact. (2) The fracture energy was 30J/m2 in the case of the surface roughness of 5μm.抄録全体を表示PDF形式でダウンロード (3004K) -
高橋 渉, 小原 公一, 石垣 尚幸1998 年 45 巻 2 号 p. 176-181
発行日: 1998/02/15
公開日: 2009/05/22
ジャーナル フリーThe application of Nd-Fe-B sintered magnets to the electronic parts has been greatly progressed and Nd-Fe-B sintered magnets are demanded to possess further excellent magnetic properties. Recently, Rubber Isostatic Pressing(RIP) method have been developed to get the high magnetic performance. Since in RIP, powders of the magnet inside rubber die are pressed like the isostatic process, the orientations of C axis of the powders don't change. Therefore, the magnet made by RIP shows superb magnetic properties. But, the effects of the RIP process conditions on the compactibility have not been clear because of the complicated behaviors of powders of the magnet and the rubber die in magnetic field. From obtained results through this study, it has been proved that the problems of RIP method are the bad compactibility such as the occurrence of the cracking and marked deviation in outer dia. of the RIP green compact although Nd-Fe-B sintered magnets made by RIP showed excellent magnetic properties.抄録全体を表示PDF形式でダウンロード (418K) -
伊藤 尚, 中野 和則, 高木 研一, 黒木 英憲1998 年 45 巻 2 号 p. 182-188
発行日: 1998/02/15
公開日: 2009/12/04
ジャーナル フリーThree kinds of mullite, termed CP, HK and HP mullite (in order of increasing purity) containing 30 mass% zirconia were rapidly solidified to obtain amorphous ceramic powder. The rapidly solidified (RS) amorphous powder was hot-pressed exhibiting a very fine microstructure. High temperature deformation behaviour was assessed using 3 point bending and tensile tests. It was found that (1) The RS specimens exhibited greater ductility than the non RS specimens in the bending test at elevated temperature. (2) The bending force at elevated temperature was dependant on the bending rate. A bending rate sensitivity index (m') of approximately 0.5 was derived from a bending rate (ν) of 10-3 mm s-1 for both HK-RS and HK-non RS materials. The bending force for the RS material was lower than that of the non RS material. (3) The tensile stress at elevated temperature was dependant on strain rate. The strain rate sensitivity index (m) was approximately 0.5 at an initial strain rate (ε) of 2.5×10-4 s-1 for both HK-RS and non RS materials. The flow stress for the RS material was lower than that of the non RS material. A fracture strain of 80% was achieved at the same strain rate for RS material. (4) The ductility exhibited by the RS materials increased at elevated temperature. This was attributed to the ultrafine microstructure which was thought likely to encourage superplastic behaviour.抄録全体を表示PDF形式でダウンロード (7621K) -
長江 正寛, 国定 昭宏, 高田 潤, 平岡 裕, 竹元 嘉利, 飛田 守孝, 桑原 秀行1998 年 45 巻 2 号 p. 189-194
発行日: 1998/02/15
公開日: 2009/12/04
ジャーナル フリーFor dilute Mo-Ti alloys and pure Mo nitrided at 1100°C for 16h in NH3 and N2 gases, microstructural observations through optical and transmission electron microscopes, X-ray diffraction analysis and hardness measurements were carried out and the nitriding behavior in N2 and NH35 gases was compared. A surface layer of γ-Mo2N with Hv-1700 was formed for the nitriding in NH3 gas of 1 atm. In contrast, the surface layer was absent for nitriding in N2 gas at pressures below 10 atm, whereas the β-Mo2N layer was formed at a pressure of 15 atm. In an internal nitriding layer formed beneath the surface layer of Mo-Ti alloys nitrided in NH3 gas, extremely small and plate-like particles of 2-4nm in width and approximately 0.45nm in thickness were clearly found to precipitate on {100} planes of the matrix. Furthermore, a large coherent strain field was observed in the matrix around each Ti-nitride precipitate. Such a dispersion of the small precipitates resulted in remarkable hardening in the nitrided alloy. The hardness of the internal nitriding layer of the alloys nitrided in NH3 gas was much higher than that in N2 gas. The difference in hardness can be explained in terms of the differences not only in size of the Ti-nitride precipitates but also in their distribution density.抄録全体を表示PDF形式でダウンロード (7382K)
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