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[in Japanese], [in Japanese]
1977 Volume 63 Issue 9 Pages
1433-1434,1605
Published: August 01, 1977
Released on J-STAGE: March 15, 2010
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Kazuyuki SAKURAYA, Koji KAMIYA, Minoru TANAKA
1977 Volume 63 Issue 9 Pages
1435-1442
Published: August 01, 1977
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To improve contacting efficiency between reducing gas and iron ore particles in fluidized bed reduction, the effect of internals which were arranged in 2-dimentional cold model was investigated. In the case of without internals, gas bubbles became large with increasing gas velocity, but with horizontal internals arranged in equilateral triangle in the model, gas bubbles were well dispersed and large size bubbles were not observed.
Using 2-dimentional reduction reactor which had the same dimention as the cold model, the effect of internals on the reduction rate of iron ore by H
2 at 700°C with the same bubbling condition as the cold model was investigated. The effect of internals on the overall reduction rate was not significant.
From the relation of height of bed, gas conversion ratio and the level where large bubbles appeared in the cold model, it was considered that partial pressure of H
2O in H
2 almost approached to the equilibrium of FeO-Fe reduction before gas bubbles became large.
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Kiichi NARITA, Masahiro MAEKAWA
1977 Volume 63 Issue 9 Pages
1443-1452
Published: August 01, 1977
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An investigation has been carried out on the behavior of pellets during the reduction in the lower part of blast furnace. Pellets samples taken from an industrial blast furnace were large and very hard masses, whose section showed a zonal structure; a spherical envelope of metallic iron was formed in the external part of each pellet and unreduced core remains in the central part.
When pellets become such a large mass with unreduced ore in the blast furnace, this core must be reduced by direct reduction in the liquid state after melting of this mass. In consequence, the blast furnace performance becomes undesirable, with an increase of coke rate, for example.
We have studied therefore, in the first step, on the properties of pellets samples taken from the blast furnace and, in the second step, on the condition on metallic iron shell formation and its mutual cohesion in order to obtain the fundamental data. The results obtained are as follows:
(1) The chemical analysis and microscopic investigation into the pellets taken from the blast furnace shows that the shell consists of much metallic iron, a little wustite and slag. Its melting point is 1560°C. On the other hand, the core consists of much wustite, and small amounts of metallic iron and slag. Its melting point is 1360°C.
(2) When a pellet prereduced to wustite is reduced by reducing gas containing 30%CO+70%N
2 at 1200°-1250°C during 30-60 minutes, a dense metallic iron shell of about 1.5mm in thickness is formed.
(3) Strong mutual cohesion takes place among pellet particles, by heating pellets having metallic iron shell in the atmosphere of N
2 at 1250°-1300°C during 30-60 minutes under a lord of 1.0kg/cmcm
2.
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Kazuo ARAKI, Akira MORIYAMA
1977 Volume 63 Issue 9 Pages
1453-1459
Published: August 01, 1977
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Gas flow patterns and pressure profiles through packed and moving beds with layered burdens have theoretically and experimentally been studied.
In the middle region of the beds, periodic behaviours of gas flow correspond with the alternative packings of the beds. In the top and the bottom region, gas flow tends to concentrate to a lower resistant part of the beds. The velocity profiles of gas flow at the inlet part of the beds cannot be described with such a simple expression as a linear equation. Usually, the total pressure drop through the beds is smaller than the estimation based on “parallel-flow model. ”
Flow patterns of gas in the top region ofthe beds are not very affected by the packing structure of the botttom region of the beds and similarly flow patterns in the bottom region are not affected by the packing of the top region.
The third layer imposed in the bottom part of the beds, an inclination of top surface and angles of repose of the packed burdens also have a considerable effect on both pressure profiles and flow patterns through the beds.
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Yoshio NAKANO, Masaru ISHIDA, Takashi SHIRAI
1977 Volume 63 Issue 9 Pages
1460-1469
Published: August 01, 1977
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By gradual decrease in the partial pressure of watcr-vapor in H
2-H
2O mixtures at 900°C, the powders of sintered hematite were reduced step by step, i. e., first magnetite then to wustite and finally to iron. The variations of both the gas composition and fractional reduction were measured simultaneously.
Except in the wustite range, the reduction rates obtained under such continuous changes of gas composition were found to be nearly equal to those obtained by the reduction of the pre-reduced magnetite under constant gas concentrations.
When the partial pressure of water-vapor at the start of the reduction was low, the reduction rates under continuous changes of gas composition were nearly equal to those obtained by reducing the pre-reduced wustite or the original hematite sample under constant concentration.
In the wustite range, however, the reduction rates under continuous changes of gas composition became extremely low, especially when the change in partial pressure of water-vapor in the reducing gas became slow. It was found that iron was not produced, when the ratio of partial pressure, PH
2O/ (PH
2+PH
2O), was decreased very slowly and then kept even for two hours at 0.343 which was far less then the equilibrium ratio, 0.388.
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Kanae SUZUKI, Koh-ei NAKABAYASHI, Kazumi MORI
1977 Volume 63 Issue 9 Pages
1470-1475
Published: August 01, 1977
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The effect of Co, Ni and Cr on the rate of CO removal from liquid iron has been studied at 1 580°C in the composition range of oxygen transport controlling. The mass transfer coefficient of oxygen (k
O) is little affected by addition of Co or Ni. On the other hand, k
O decreases markedly with increase of Cr content. The results are interpreted reasonably in terms of thermodynamic interaction parameters in the alloy systems.
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Yoshio WASEDA, Yutaka SHIRAISHI
1977 Volume 63 Issue 9 Pages
1476-1483
Published: August 01, 1977
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A detailed analysis of X-ray scattering intensity of molten Fe-P and Fe-Si alloys has been carried out by X-ray diffraction with anomalous scattering technique. The three partial structures required to characterize a binary molten alloy have been estimated. It is found that the fundamental configuration of atoms for molten Fe-P and Fe-Si alloys consists mainly of the disorderly distributed Fe atoms like those in the dense random packing model of liquids. But it is also confirmed that the short range order in the near neighbour distance for molten Fe-P alloys is similar to that of Fe
3P type.
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Kusuhiro MUKAI, Hirofumi FURUKAWA, Takashi TSUCHIKAWA
1977 Volume 63 Issue 9 Pages
1484-1493
Published: August 01, 1977
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Interfacial tensions between liquid dilute Fe-Si-O alloys and CaO-SiO
2-FeO slags were determined using the sessible slag drop on the surface of the metal. This drop was maintained by a basket of thin Pt and PtRh (20%) wires, which enabled to obtain both equilibrium and nonequilibrium interfacial tensions, preventing the two liquids from the contamination from the container. Results obtained are as follows:
(1) As a whole, an increase in oxygen content of the metal substantially lowers the equilibrium interfacial tension σ
0ms and also nonequilibrium one σ
0ms.
(2) Dependencies of σ0ms, a nonequilibrium value obtained at the beginning stage of iron transfer from the metal to the slag, on the oxygen content of the metal and temperature differ from those of σ
ems. These differences increase in magnitude with an increase in the oxygen content of the metal.
(3) An increase in FeO content of the slag substantially lowers σ
0ms, a nonequilibrium value obtained at the biginning stage of iron transfer from the slag to the metal. This effect of FeO increases markedly with an increase in the oxygen content of the metal.
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Toshiharu FUJISAWA, Hiroshi SAKAO
1977 Volume 63 Issue 9 Pages
1494-1503
Published: August 01, 1977
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The equilibrium relations between the liquid iron alloys of Fe-Mn-Si-Al-O system and the deoxidation products were studied.
Assuming that the products formed during the complex deoxdation with Mn-Si-Al alloys consisted of MnO, SiO
2, and Al
2O
3, the activities of the constituents in the MnO-SiO
2-Al
2O
3 system were determined thermochemically.
Using these results, the equilibrium relations between MnO-SiO
2-Al
2O
3 oxides and liquid iron were estimated at the condition of %Mn+%Si=1.
At the same time, the measurements on the equilibrium between the liquid iron alloys and the oxide inclusions were carried out at the melting temperature of the iron alloys, approximately 1535°C. The deoxidation products were trapped directly underneath the solid-liquid interface of metal without any contamination by the container material.
The experimental results agreed fairly well with the thermochemical calculation.
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Toshiharu FUJISAWA, Hiroshi SAKAO
1977 Volume 63 Issue 9 Pages
1504-1511
Published: August 01, 1977
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This study is aimed to obtain the data of the activities of MnO and SiO
2 in MnO-SiO
2-Al
2O
3-FeO slags saturated with Al
2O
3, and of the equilibrium between manganese, silicon and oxygen in liquid steel at 1550°C.
The results are summarized as follows:
The FeO content in the slag is less than 3mol%. Both aMnO and aSiO2 change linearly against the ratio of (NMnO+NFeO) /NSiO
2 in the region of the ratio from 0.5 to 1.3. The activity of SiO
2 in the slag saturated with mullite (3Al
2O
3·2SiO
2) and Al2O3 is 0.42, and the activity of MaO in the slag saturated with galaxite (MnO.Al
2O
3) and Al2O3 is 0.15 at 1550°C.
The oxygen content in liquid Steel in equilibrium with slags saturated with Al
2O
3 is calculated. It is in good agreement with the results of the previous experimental work of present aulthours.
The liquldus lines of Al
2O
3, mullite and galaxite in MnO-SiO
2-Al
2O
3 system at 1550°C are determined. and the iso-activity lines for MnO and SiO
2, which were determined thermochemically in the previous work, correct and represent in the ternary diagram.
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Shigeo ASAI, Takahiko SAHARA, Iwao MUCHI
1977 Volume 63 Issue 9 Pages
1512-1519
Published: August 01, 1977
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To clarify the mechanism causing “channel-type” segregation, model experiments are conducted with aqueous solutions of NH
4CL to make formation processes of the channels and flow pattern in the mushy zone visible.
By taking account of the observed results, theoretical analysis of the simultaneous heat, mass and momentum transfer in the mushy zone is carried out to develop a mathematical model for the “channel-type” segregation.
The instability of the system which might lead to the occurrence of the “channel-type” segregation is qualitatively considered, followed by a quantitative treatment with the aid of the model.
The experimental results obtained by other investigators with regard to the formation of the “channeltype” segregation are interpreted on the basis of the numerical results obtained from the model.
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Sumio SHIOMI, Nobuo SANO, Yukio MATSUSHITA
1977 Volume 63 Issue 9 Pages
1520-1528
Published: August 01, 1977
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In the reduction of BOF slag with carbon, for the purpose of its reclamation, not only P
2O
5 but also FeO are reduced to form Fe-P-C alloy from which phosphorus should be removed later for the utilization of byproducts. According to this concept, firstly, experiment has been made of the reduction of synthetic slags and BOF slag (I), secondly, the evaporation of phosphorus (the species is P
2) from the alloy obtained at the first stage, adding silicon in order to increase the activity of phosphorus by use of levitation technique (II).
The results of two type of experiments are summarized as follows:
A large amount of iron oxide is reduced until the reduction of P
2O
5 starts (I-1).
The dephosphorization of iron free slags by carbon is controlled by the chemical reaction (I-2).
The vacuum treatment significantly enhances the dephosphorization of Fe-Si-P alloys and the minimum content of phosphorus, 0.005%, is obtained in 7 minutes (II-1).
The evaporation rate of phosphorus from Fe-Si-P alloys increases with increasing silicon content and the rate determing step is the transport of P
2 in gas phase with some exceptions (II-2).
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Hideo YOSHIDA, Shoichi KATO
1977 Volume 63 Issue 9 Pages
1529-1538
Published: August 01, 1977
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Some melts of 18-8 stainless steel of 10kg were deoxidized at 1550°C with (1) Si, (2) Al, (3) Si-Mn, (4) Al after Si-Mn, (5) Si-Mn-Al by using induction furnace. The experimental results were analysed on the basis of thermodynamics and kinetics and summarized as follows:
(1) Oxygen content decreases rapidly until it reaches to 40 ppm in the deoxidation with Al, while some sluggishness of the deoxidation occurs at about 1 to 10min after the addition of Si-Mn, depending on the amount of Si and Mn, and subsequently oxygen content decreases again and reaches to the equilibrium, about 110 ppm with 0.6% Si and 1.6% Mn. These values are consistent fairly well with those of the calculated.
(2) The separation constant of deoxidation, k in (Me
xO
y) %=C
0 exp (-kt) becomes smaller, in order of with Al, Si-Mn, Si-Mn-Al, and Si. The difference of the deoxidation behavior between with Al and Si-Mn (depending on Si and Mn contents) is to be interpreted on the characteristic of coalescence of their deoxidation products, i. e., clustering of Al
2O
3, fused Mn-Silicate, semi-liquid SiO
2 and solid Mn-Chromite.
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Tetsuya SAITO, Iku UCHIYAMA
1977 Volume 63 Issue 9 Pages
1539-1548
Published: August 01, 1977
Released on J-STAGE: July 27, 2010
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The relation was studied between the tensile properties and plane strain fracture toughness of secondary hardening steels, using three experimental Ni-Cr-Mo-V steels with different carbon contents. The plane strain fracture toughness was estimated by the critical J-value obtained from precracked three-point bending tests. The results obtained could be summarized as follows:
(1) The tensile strength and ductility of the present steels are dependent remarkably on the carbon content, this dependency being similar for all the aging temperatures studied.
(2) The plane strain fracure toughness is also affected by the carbon content and aging temperature of the secondary hardening range. The aging temperature where the plane strain fracture toughness has a minimum value coincides nearly with that at Which the ultimate tensile strength is the greatest.
(3) The tensile ductility and plane strain fracute toughness derease with an increase in strength level. At a constant strength level, however, the tesile ductility has an increasing tendency with an increase in aging temperature and the plane strain fracture toughness shows a tendency contrary to that.
(4) The above contrasting bevavior results from the differnce in fracture modes, to which the multiaxial stress state near the precrack tip contributes.
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Tatsu FUJITA, Atsuo MIZUTA, Osamu TSUDA
1977 Volume 63 Issue 9 Pages
1549-1555
Published: August 01, 1977
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Unstable ductile fracture criteria of a power hardening material have been investigated to derive the relation between a critical remote uniform strain at fractureε
f and a crack length c of plate specimen under uniaxial plastic extension.
(1) The fracture criterion is given by the following equation based on the energy consevation law. ε
f c
1/1+n1/1+n=const.
(2) The theory has been approved by the experiment on the saw cut notched plates of normalized 0.8 %C steel, 0.17%C steel and austenitic stainless steel. The results of numerical analyses by the finite element method also reasonably support the validity of the theory.
(3) The present criterion is identical with Griffith criterion in the brittle fracure when strain hardening exponent n=1. In view of this theory one can have better understanding about the reduction of area in, the conventional tensile test, and a whole physical interpretation of ductility of material is obtained throughout tensile test, unstable ductile fracture and brittle fracture.
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Taku SAKAI, Masayuki OHASHI, Masahumi KOZAI, Seita SAKUI
1977 Volume 63 Issue 9 Pages
1556-1563
Published: August 01, 1977
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The effect of grain size on the tensile defomation behaviour of 1 and 3wt% Si-Fe alloys was studied over the temperature range from 25° to 800°C at strain rates of 10
-5 and 11/sec. The relations between the grain size and yield stress or flow stress at a given straln in both alloys were approximately represented by the Hall-Petch equation over the experimental range. The yield behaviour in both alloys was discussed to be separated into the following four temperature regions; (1) the low temperature deformation region below 300°C, (2) the athermal deformation region between 300° and 500°C, (3) the region of yielding phenomenon between 500° and 700°C, and (4) the high-temperature deformation region above 700°C.
The value of friction stress for yielding, σ
o, and its temperature and strain rate sensitivities in the region (3) increased with increasing Si content. For both alloys was also observed a new yielding phenomenon in the region (3). The apparent activation energy for this yielding was unchanged with Si content and about 93kcal/mol, and the activation area was changed with it, i. e. 170-200 bb
2 in 1% Si alloy and 70-100 bb
2 in 3% Si alloy.
The grain size dependnce of flow stress in the regions (3) and (4) was comlicated with the change of temperature and strain. This behaviour was explained qualitatively in terms of the modified work hardening model. The change in steady-state or maximum flow stress, σ
M, with Si content was almost the same to that of σ
o, and then the internal stress developed during defbrmation, σ
i (σ
M-σ
o) was considered to be nearly constant regardless of the Si content.
These results indicated that the high-tmeperature deformation mechanism in the two Si alloys was different from that of pure iron, and during the deformation the dislocation glide was considered to play an important role.
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Osamu HAIDA, Toshihiko EMI
1977 Volume 63 Issue 9 Pages
1564-1571
Published: August 01, 1977
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Solid/ Liquid interfacial free energies, σ
sl in iron group transition metals, Fe, Co, and Ni, and Sn and Bi have been calculated by Ewing's theory. Methods of experimental determination of σ
sl have also been critically reviewed to yield the conclusion that, despite of known difficulties involved, the method by measuring the citical supercooling for homogeneous nucleation gives the most comprehensive, rather reliable data, σ
M.S. sl, to be compared with the theoretical prediction. The balues of σ
M.S. sl, however, exhibit negative deviations of about 13 to 30% from the corresponding ones determined by the interface intersection method. Temperature correction for at melting point makes the deviation smaller by about 10%, decreasing the maximum probable error to be about 20%. The theoretical prediction after EWING is shown to give much better agreement (±10%) with the temperature corrected values,
M.S. sl (T
m), than those after SKAPSKI or ZADUMKIN.
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Yoshisada UEDA, Noboru WADA
1977 Volume 63 Issue 9 Pages
1572-1580
Published: August 01, 1977
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An investigation has been carried out on the process and the mechanism of austenitizing of spheroidal graphite cast iron by dilatometric and metallurgical methods.
The austenitizing is affected remarkably by the microstructure, and the rate of the transformation reduces in the order of pearlitic, Bull's-eye, and ferritic structures.
In ferritic spheroidal graphite cast iron, austenite phase forms mainly around the graphite nodules at high temperature and along the ferrite grain boundary at low temperature.
The transformation is retarded by increasing silicon contcnt, due to the elevation of A
c1 temperature and reduction of austenite.
Exponent, n, in the rate equation of the austenitizing (Johnson-Mehl equation) takes considerably lower values than 3.
The experimental results fairly coincide with the calculated one by a diffusional model.
It is assumed that the austenitizing of ferritic spheroidal graphite cast iron is controlled by carbon diffusion, and there exists a steady state reacion except for the early stage.
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Yasuo INOKUMA, Jyo ENDO
1977 Volume 63 Issue 9 Pages
1581-1587
Published: August 01, 1977
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A study has been carried out on the atomic absorption spectrometry to determine arsenic in iron and steel by an indirect amplification procedure.
The present technique involves that arsenomolybdic acid is formed in nitric acid solution and extracted into the mixed organic solvent (n-butanol 1, iso-butyl acetate 1 and iso-amyl acetate 2) after the coexistent phosphomolybdic acid is eliminated by extracting into iso-butyl acetate, and then the amount of molybdenum associated with the arsenic is determined by atomic absotption spectrometry with a nitrous oxide-acetylene flame in the organic phase.
The method is free from interference by the coexistent elements in iron and steel.
Arsenic in iron and steel can be determined down to 2ppm with this method. The results obtained agreed with the certified valued of the standard samples. The reproducibility by the method in the coefficient of variation is 5.0, 1.7 and 2.7% for 0.2, 1.0, and 2.0μg As/ml. respectively.
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Kiyota YOSHIDA
1977 Volume 63 Issue 9 Pages
1588-1596
Published: August 01, 1977
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Tadaaki YANAZAWA, Jun MIYOSHI
1977 Volume 63 Issue 9 Pages
1597-1600
Published: August 01, 1977
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Yukio MATSUSHITA
1977 Volume 63 Issue 9 Pages
1601-1604
Published: August 01, 1977
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
1977 Volume 63 Issue 9 Pages
1608-1615
Published: August 01, 1977
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1977 Volume 63 Issue 9 Pages
N157
Published: 1977
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
1977 Volume 63 Issue 9 Pages
A71-A82
Published: August 01, 1977
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1977 Volume 63 Issue 9 Pages
A83-A102
Published: August 01, 1977
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
1977 Volume 63 Issue 9 Pages
A103-A122
Published: August 01, 1977
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
1977 Volume 63 Issue 9 Pages
A123-A142
Published: August 01, 1977
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1977 Volume 63 Issue 9 Pages
A143-A158
Published: August 01, 1977
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1977 Volume 63 Issue 9 Pages
A159-A174
Published: August 01, 1977
Released on J-STAGE: July 27, 2010
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