WANG Ruikun SUN Lihong LI Dongpei YING Qiming T.Takeyama General Research Institute for Non-Ferrous Metals
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Beijing
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China [Originally published in ACTA METALL SIN (CHINESE EDN) 24 (5) 1988 pp B353—B358
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received 6 May 1987
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in revised form 6 February 1988] T.Takeyama is an emeritus professor of HOKKAIDO University
,
Japan
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and now is a technical adviser of GRINFM
金属学报(英文版)
The magnetic domain structure and related magnetic properties of (NdPr)_(16)Fe_(76)B_8 permanent magnet have been studied by colloid-SEM method.In thermally demagnetized state,the ma- trix grains in the magnet generally exhibit multidomain structure,i.e.,180° plate-like indi- vidual domain and a few spike-like or maze-like domains.The average width of the domain measured was 1.5μm.Grain size of single-domain was observed to be generally about 1μm and only a few up to 3μm.The results calculated are:the domain wall energy γ=36 MJ/m~2,the exchange constant A=4.5×10~(-11)J/m,the domain wall width δ=15.7nm, and the critical grain diameter of single-domain D_c=0.5μm.The dependence of high magnet- ic field gradient at grain boundaries in different magnetization directions in the adjacent mag- netic domains located on both sides of grain boundaries and the effect of microstructure on the values of K,A and δ were discussed.
关键词:
Nd-Fe-B permanent magnet
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null
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null
MA Zongyi YAO Zhongkai Harbin Institute of Technology
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Harbin
,
China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
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null
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null
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null
Corrosion
This paper introduces the design of a localized corrosion rate monitoring instrument that can monitor and evaluate the maximum and stable localized corrosion rate of a nonpassivable metal in a corrosive environment by measuring the current density in a corrosion sensor with an occluded anode.
关键词:
instrument;localized corrosion rate;monitor
Ming FANG
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Qinghui LI
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Fuxi GAN
材料科学技术（英文）
The optical absorption properties of phase-change optical recording thin films subjected to various initialization conditions were investigated. The effects of initialization power and velocity on optical constants of the Ge2Sb2Te5 thin films were also studied. The energy gap of Ge2Sb2Te5 thin films subjected to various initialization conditions was also obtained. It was found that the optical energy gap of the Ge2Sb2Te5 thin films increased with either increasing initialization laser power or decreasing initialization velocity, with peak of 0.908 eV at laser power of 1000 mW or initialization velocity of 4.0 m/s, but the continued increasing initialization laser power or decreasing initialization velocity resulted in the decrease of the optical energy gap. The change of the optical energy gap was discussed on the basis of amorphous crystalline transformation.
关键词:
Phase transformation
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null
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null
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null
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null
G. Y. Gan and L.Z. Wang (Pingguo Aluminum Company
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Pingguo 531400
,
China)
金属学报(英文版)
The control techniques for indirect heating digestion in Bayer process of alumina production were researched and developed. They include controlling chemical composition of slurry to be digested and controlling digestion status and energy consumption. Very good performances and technical and technical and economical figures for digestion process have been obtained by carefully applying these comprehensive control techniques in Pingguo alumina refinery.
关键词:
control technique
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null
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null
ZHANG Fu-ming
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MAO Qing-wu
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MEI Cong-hua
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LI Xin
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HU Zu-rui
钢铁研究学报(英文版)
In Shougang Jingtang 5500 m3 huge blast furnace (BF) design, dome combustion hot blast stove (DCHBS) technology is developed. DCHBS process is optimized and integrated, and reasonable hot blast stove (HBS) technical parameters are determined. Mathematic model is established and adopted by computational fluid dynamics (CFD). The transmission theory is studied for hot blast stove combustion and gas flow, and distribution results of HBS velocity field, CO density field and temperature field are achieved. Physical test model and hot trail unit are established, and the numeral calculation result is verified through test and investigation. 3-D simulation design is adopted. HBS process flow and process layout are optimized and designed. Combustion air two-stage high temperature preheating technology is designed and developed. Two sets of small size DCHBSs are adopted to preheat the combustion air to 520-600 ℃. With the precondition of BF gas combustion, the hot blast stove dome temperature can exceed 1420 ℃. According to DCHBS technical features, reasonable refractory structure is designed. Effective technical measures are adopted to prevent hot blast stove shell intercrystalline stress corrosion. Hot blast stove hot pipe and lining system are optimized and designed. After blowing in, the blast temperature keeps increasing, and the monthly average blast temperature reaches 1300 ℃ when burning single BF gas.
关键词:
dome combustion hot blast stove
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high blast temperature
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ceramic burner
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high temperature combustion air preheating
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CFD
