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[in Japanese]
1993 Volume 40 Issue 11 Pages
1036
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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Minoru Ogawa, Yasuo Takeda, Nobuyuki Imanishi, Osamu Yamamoto
1993 Volume 40 Issue 11 Pages
1037-1040
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The solid solution region of infinite-layered copper oxide Ca
1-xSr
xCuO
2 was studied under various oxygen partial pressure.The stability region expanded with decreasing oxygen pressure. The trials for electron or hole doping were tried, the intercalation of Li ion by the discharge in Li-battery was possible forming (Ca
0.85Sr
0.15)
0.9Li
xCuO
2(x ?? 0.2). Both a and c axes increased with increasing x, indicating the reduction of oxidation state of Cu, but it did not bring about superconductivity.
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Akinori Irisawa, Shinichi Kikkawa, Fumikazu Kanamaru
1993 Volume 40 Issue 11 Pages
1041-1044
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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Heat treatment effects were investigated on T'-type 214 compounds Ln
1.85Ce
0.15CuO
y with Ln=Pr, Nd, Sm or Eu. Annealing in sealed tube did not much affect on their electrical behavior of superconducting Nd
1.85Ce
0.15CuO
y. Electrical resistivitiy was reduced in the case of Ln=Sm and Eu but was enhanced on Ln=Pr with the annealing. Unit cell volume expanded with a decrease of oxygen content on Ln=Nd but shrank on Ln=Pr. These results could be understand as follows:trivalent neodymium ion has suitable ionic size in T'type structure, samarium and europium ions are too small so that oxide ion defect is easily introduced in the fluorite layer to expand its size to fit with the CuO
2 conduction plane, and praseodymium is too large so that CuO
2 conduction plane partially release its oxide ion. Surface of superconducting Nd
1.85Ce
0.15CuO
y was oxidized within 50days to the condition before the reduction to make the sample superconducing even if the sample was kept in a vacuum desiccator.
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Yasuo Mukai, Yasuo Takeda, Nobuyuki Imanishi, Osamu Yamamoto
1993 Volume 40 Issue 11 Pages
1045-1048
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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Superconductivity in La
2-xCd
xCuO
4+z(0≤x≤0.1) and La
2-xPb
xCuO
4+z(0≤x≤0.15) were studied. The solid solutions prepared under ambient pressure and high oxygen pressure showed only semiconducting property, although they have enough formal valence of copper such as +2.1-2.15. Strong oxidation by electrochemical treatment only brought about superconductivity at Tc=20-40K for La
2-xCd
xCuO
4+z and 15-20K for La
2-xPb
xCuO
4+z
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Yoshihiro Kusano, Tokuro Nanba, Jun Takada, Yasunori Ikeda, Mikio Taka ...
1993 Volume 40 Issue 11 Pages
1049-1052
Published: November 15, 1993
Released on J-STAGE: December 04, 2009
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Phases and their relations in the BiO
1.5-SrO(SrCO
3)-CuO system have been studied mainly by XRD. The crystal structure of the newly found phase has been examined by XRD, TEM and ED. Phase equilibrium was established at 720°C in air. Monophasic products of the newly found phase were obtained at 720°C for a composition of Bi:Sr:Cu=0.25:0.55:0.20. The newly found phase has a tetragonal structure with lattice parameters of a=5.513Å and c=39.93Å.
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Effect of O2-partial Pressure
Naoya Kobayashi, Minoru Fukuhara, Akira Doi, Toshio Takada, Yoshihiro ...
1993 Volume 40 Issue 11 Pages
1053-1056
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The effects of O
2-partial pressure on formation of the Bi-2223 phase. The samples were heated at 807°C-850°C under various O
2 atmospheres after calination in air or Ar flow. Single phase products of the 2223 phase were obtained by heating in 20%O
2 both in Ar and air. The Pb-substituted 2212 phase, (Ca, Sr)
2Cu0
3 and CuO coexist in samples calcined i n Ar. The 2223 phase forms at a markedly lower temperature (807°C) in samples calcined in Ar than in those in air. In samples calcined in Ar, the 2223 phase forms without formation of (Ca, Sr)2PbO4. These results reveal that the formation process of the 2223 phase in samples calcined in Ar is different from that i n thoseinair.
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Yoshihiro Kusano, Tokuro Nanba, Jun Takada, Yasunori Ikeda, Mikio Taka ...
1993 Volume 40 Issue 11 Pages
1057-1060
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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Chemical stability of the Bi-2223 phase has been studied for the samples Bi
0.9Pb
0.2SrCaCu
1.6O
2 Annealing of the bulk samples below 800°C leads to precipitation of the 3321 phase identified as Sr
2.5Bi
0.5Pb
3Ca
2CuO
z. The precipitation of the 3321 phase from the 2223 phase decreases the volume fraction of the 2223 phase but Tc (x) remains unchanged. It was found by XRD and SQUID measurements and SEM observation that, through reheating at 850°C after heating at 750°C, the 3321 phase disappeares and the volume fraction of the 2223 phase perfectly recovers.
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Tsuyoshi Nishizaka, Akira Hane, Kazuhiko Kato, Hirohumi Kotaka, Kazuto ...
1993 Volume 40 Issue 11 Pages
1061-1064
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The effect of the cooling process on superconductivity has been studied for the samples with nominal compositions of Bi
1.6Pb
0.5Sr
2.0Ca
2.0Cu
3.0O
z sintered at 1123K for 80h in air. The results are summarized as follows:
(1) Samples which have the cooling rates of the range from 1 to 100K/minn have shown good superconductivity, the critical temperature > 100K and the critical current density > 80A/cm
2.
(2) From TG measurements, the two oxidation peaks in cooling process have been observed, where these high and low temperature peaks seem to be related to the reactions of 2223 and 2212 phases, respectively.
(3) The critical current density has increased from 80 to 165A/cm
2 by the cooling process with holding at 1093K for a few hours.
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Comparing the Various Bi-2201 Solid Solutions
Toshinobu Niinae, Jun Takada, Yasunori Ikeda, Yoshichika Bando
1993 Volume 40 Issue 11 Pages
1065-1068
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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Mechanical grinding and the reformation from ground powder of the "2201" phase doped Pb, Ca and Ba were examined by XRD and DTA. The "2201" solid solutions changes easily into fine powder by mechanical grinding. The Ca-or Ba-substitution for Sr tends to suppress the formation of SrCO
3 from the ground powder on mechanical grinding in air. The formation of Bi
2CuO
4 at 400°C and the reformation of the original "2201" phase at 800°C seem to be common for the "2201" solid solutions. The ground powder consists of not amorphous powder but ultra-fine crystals. Each crystal has a diameter of 30 to 100 Å and a thickness of one unit cell or a half unit cell length and thermally unstable.
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Hironao Tanaka, Koichi Takakuwa, Shoichi Nasu, Kentaro Ohhashi
1993 Volume 40 Issue 11 Pages
1069-1072
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The effects of water, ethyl alcohol or acetone on the Jc(77K) value of superconductors in the Bi(Pb)-Sr-Ca-Cu-O system were investigated. Starting powders for sintering were prepared by calcining the mixture of the composition (a)Bi
1.8Pb
0.4 Sr
2Ca
2Cu
3.2O
y or (b)Bi
1.98Pb
0.22Sr
2Ca
2Cu
3O
y. The 1st sintered compacts of the former composition (a) were heat-treated by 4 steps and press-formed at 196MPa.
The Jc value of the samples soaked for 288h in water was lower by 25A/cm
2 than that of the sample without soaking (Jc=40A/cm
2). Those of the samples soaked in ethanol and acetone were constant. The higher value of Tc and Jc was obtained for the samples made by more steps of repress-forming and sintering. The values of Tc and Jc of 1st sintered samples without heat-treatment decreased more rapidly with soaking time affected by water and the organic solvents.
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Toshio Egi, Takashi Hase, Kazuyuki Shibutani, Seiji Hayashi, Rikuo Oga ...
1993 Volume 40 Issue 11 Pages
1073-1076
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The influence of the Ag-doping, the composition, and the structure in the critical current density (Jc) of Ag-sheathed tapes of Bi2212 superconductors were studied for samples with nominal compositions of Bi
2.0+xSr
2.0Ca
1.0Cu
1.9AgyO
z (x=0 to 0.2, y=0, 0.1). Jc of Ag-sheathed tapes were enhanced by Ag-doping and optimization of Bi content. The maximum value of the Jc was 90, 200 A/cm
2 at 4.2K in OT for x=0.1 and y=0.1.Increment of Jc was due to the highly textured 2212 phase and the decrease of the quantity of impurity phases.
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Mamoru Ishii, Keizou Tsukamoto, Hiromasa Shimojima, Chitake Yamagishi, ...
1993 Volume 40 Issue 11 Pages
1077-1080
Published: November 15, 1993
Released on J-STAGE: December 04, 2009
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When a Bi(Pb)-Sr-Ca-Cu-O cylindrical specimen was subject to a magnetic field applied parallel to the cylindrical axis, the flux profiles inside specimen were calculated based on the critical state model. These calculations agreed with the experimental results.
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Shigeru Katsuyama, Yoshinao Harada, Kazuhiko Majima, Hiroshi Nagai
1993 Volume 40 Issue 11 Pages
1081-1084
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The effect of mechanical grinding (MG) on the physical properties of YBa
2Cu
3O
y-Ag composite superconductor was examined. The critical current density (Jc) and the global pinning force (F ?? ) increase by the Ag addition. The Jc of the samples without MG treatment shows the maximum value at about Ag 8 wt%. On the other hand, that of the samples with MG treatment is constant independent of Ag content. The F ?? of the samples increases by the Ag addition, and the F ?? of the samples with MG treatment is larger than that of the samples without MG treatment. There may be difference of the distribution of Ag between in the samples without and with MG treatment.
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Toshimasa Suzuki, Takashi Yamada, Hiroshi Negishi, Tatsuya Makino, Nob ...
1993 Volume 40 Issue 11 Pages
1085-1088
Published: November 15, 1993
Released on J-STAGE: July 12, 2010
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YBa
2Cu
3O
x (YBCO) thin films have been grown on (100) MgO substrate by off-axis magnetoron sputtering. Critical temperature(Tc) of YBCO films strongly depended on substrate temperature, sputtering gas composition and total pressure and “in-situ” annealing conditions. When substrate temperature was 700°C, and gas composition and total pressure were Ar+50%O
2 and 200mTorr respectively, YBCO films of Tc=77.5K was obtained. XRD pattern of this film showed sharp (00
l) peaks showing very high c-plane orientation. Scanning tunneling microscopic (STM) image of the films showed growth spirals which were aligned to one direction. The size of the growth spirals were 150-300nm. On the other hand, when substrate temperature was 650°C, Tc was 25K and its XRD pattern showed both (h00) peaks and (00
l) peaks. STM image of this film showed both textured structures and growth spirals. We presumed that c-plane crystal shows growth spiral and a-plane one shows textured structure in sputter grown YBCO films. Patterning of YBCO thin films by photolithography did not cause the reduction of Tc.
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Yoshikazu Sadahiro, Hirotaka Honda, Masumi Koishi
1993 Volume 40 Issue 11 Pages
1089-1091
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The ingredient was treated by a hybridization apparatus for fixed time and these products were calcined at 925°C for 2 days, and annealed at 500°C for 7 days. The treatment effects on the samples were inferred from the analysis of the X-ray peaks and SEM observation. It has been clarified that the ingredient materials were very well mixed by treating for 10 minutes, so that the calcined sample was very good superconductor.
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Sunao Sugihara, Kunihito Fukushima
1993 Volume 40 Issue 11 Pages
1092-1095
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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Joinings of semiconductive BaTiO
3 with Y
1Ba
2Cu
3O
7-x were studied by hot press and by sintering in the case of thick film (about 18-30μm) of Y
1Ba
2Cu
3O
7-x. The conditions of hot press were 4 kg/cm
2 and kept for 420 minutes at 1173K in oxygen atmosphere, and three kinds of parameters on temperature and time were investigated for the thick films on BaTiO
3. The electrical resistivities were evaluated on the systems of the film/BaTiO
3 and the conditions of 1173K and 420 minute-keeping gave a superconductivity. Furthermore, the interfaces between the semiconductor and the film of superconductor were also investigated by an EPMA to show a diffusion of Cu from Y
1Ba
2Cu
3O
7-x for both methods of the joining. There seemed to be existing non-superconducting compounds, however a superconductive film on the semiconductive BaTiO
3 can be formed by optimizing the joining conditions.
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Hiromasa Mazaki, Hiroshi Yasuoka, Masato Kakihana, Masahiro Yoshimura
1993 Volume 40 Issue 11 Pages
1096-1100
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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We studied the ac-magnetic response of Co-doped YBa
2Cu
3O
7-d oxide superconductors, YBa
2Cu
3-xCo
xO
7-d (x=0-0.5), in terms of complex susceptibility χ=χ'-iχ". The samples were synthesized by the polymerized complex method. We found the onset temperature decreased with increasing x, and for x ?? 0.4, no superconducting transition was observed down to 5 K. The transition width ΔT(10-90%) for the sample of x=0.05 is 1.9 K, which is much better than that of the specimens prepared by the ordinary treatment. The transition width was also found to increase as x increases. Details of the experiment are presented together with some discussion of the coupling phase involved.
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Application of Raman Spectroscopy to High-Tc Superconductors (1)
Masato Kakihana, Hirotaka Fujimori, Masatomo Yashima, Masahiro Yoshimu ...
1993 Volume 40 Issue 11 Pages
1101-1106
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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We have investigated the phonon Raman spectra of YBa
2Cu
3-xCo
xO
7-d ceramic samples prepared by a polymerized complex method using Raman microprobe collection optics. Defect induced Raman scattering from Cu(1)-O(1) chains has been observed in Co-substituted samples, suggesting that Co predominantly enters the chain site. With increasing Co content the frequencies of the Ba, Cu(2), 0(2)-0(3) and the apex oxygen 0(4) vibrational modes along caxis change considerably. The changes are compared with those of interatomic bond distances as obtained by neutron diffraction and they indicate charge transfer effects between the CuO chain and the CuO
2 planes with increasing Co substitution. It is suggested that the O(4) mode is sensitive to small changes of the charge balance between the chain and the plane.
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Yoshimoto Wanibe, Takashi Itoh, Yoshiharu Terada, Takashi Ohara
1993 Volume 40 Issue 11 Pages
1109-1112
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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In order to examine the size distribution of non-spherical objects by means of measurements made on the random plane sections, the sectioned figures are scanned by an image analyzer. The dimensionless shape function necessary for evaluation of the distribution can be statistically determined. The function is observationally compared to the microscopic aspects and quantitatively contrasted with the previous results summarized by the different measurement and analysis of the identical samples.
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Yoshimoto Wanibe, Takashi Itoh, Yoshiharu Terada, Takashi Ohara
1993 Volume 40 Issue 11 Pages
1113-1116
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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The size distribution of non-spherical objects is stereologically estimated by measuring the unidirectional maximum diameters of the sectioned figures, in consideration of the dimensionless shape functions having been previously determined on the basis of the outlines of the figures. The distributions obtained as histograms are also analyzed according to the compound log normal law previously proposed for quantitative comparison.
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Yoshimoto Wanibe, Takashi Itoh, Yoshiharu Terada, Takashi Ohara
1993 Volume 40 Issue 11 Pages
1117-1120
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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From measurements made on random sections of non-spherical objects, the shape functions have been statistically determined and the size distributions have been able to be stereologically estimated. Then the distributions obtained as histograms have been summarized by using the proposed compound log normal law. The results are quantitatively compared with the other corresponding ones which have been procured from the measurements made on the projected shadows of the identical objects. According to discussion on the effect of the shape functions on the size distributions, mean values of the size estimated on the usual assumption of spherical objects contain the relative errors amounting to 10-40% at the circularity of even less than 0.98.
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Toshihiko Yamaguchi, Yasushi Ihata, Shinji Ando, Hideshi Miura, Tadato ...
1993 Volume 40 Issue 11 Pages
1121-1125
Published: November 15, 1993
Released on J-STAGE: December 04, 2009
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The relationship between the behavior of fatigue crack growth and the pattern of fractured surface was investigated on the sintered irons and alloyed steels for various stress ratios by using 1/2 compact type specimens. The results obtained were summarized as follows:
(1) The fracture pattern in the fatigue crack growth on the sintered ferrous materials consisted of shear and intergranular fractures, striation like pattern, and pore surface.
(2) The fracture surface reflected the shear and local intergranular fractures in the region of low crack growth rate, while most of the fracture surface were occupied by the straiation like pattern in the region of high crack growth rate.
(3) As the stress ratio increased, the fracture surface in the fatigue crack growth became coarser and many microcracks appeared within the facets. This behavior was independent on the density and the addtional alloying elements.
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Yoshiharu Yamamoto, Shoji Yamada, Satoru Honkawa, Noriyoshi Shigaki
1993 Volume 40 Issue 11 Pages
1126-1130
Published: November 15, 1993
Released on J-STAGE: May 22, 2009
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To define the optimum formation condition of ammonium tungsten bronze (ATB) which is very important intermediate for production of ultrafine tungsten, thermal decomposition of monoclinic and orthorhombic ammonium paratungstate (APT) was studied by thermogravimetry and differential thermal analysis in various atmospheres. The intermediate has been investigated by X-ray diffraction analysis and nitrogen measurement.
ATB was formed in hydrogen, in a mixture of nitrogen and ammonia, in nitrogen, in argon, in air and in oxygen atmosphere respectively. The amount of ATB formed during thermal decomposition of APT depended on the degree of proceeding of thermal decomposition near by 630 K. In case of much sample amount, reaction rate was reduced due to the endothermic reaction related to thermal decomposition of ammonia and water in crystallization.
A small amount of ammonia was necessary for a stable formation of ATB, and the nitrogen content was above 0.8 % in single-phase ATB.
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Osamu Terada, Minoru Saito, Hisashi Suzuki
1993 Volume 40 Issue 11 Pages
1131-1135
Published: November 15, 1993
Released on J-STAGE: December 04, 2009
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Formation of micro-pores in TiC-Mo
2C -Ni cermet with the addition of zirconium carbide(ZrC) up to 6 mass% was mainly studied. It was assumed that zirconium oxide(ZrO
2) formed on the surface of ZrC particles during preparation of mixed powder was reduced in the liquid phase which appeared at sintering temperature, resulting in the formation of pores. It was shown that, when the green compact was held under the solid state in a vaccum at temperature of 1250°C before sintering, the tendency of pore-formation was suppressed with increasing holding time and carbon content of the alloy. The well known phenomenon, that is, the increased creep strength of cermet due to ZrC addition was attributed to the decrease of carbon content caused by the reduction of ZrO
2.
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