Y. Q. Jia1)
,
J. G. Li1)
,
Y. M. Wang2)
,
L. X. Ding2)
,
X. M . Qin1) and X. D. Sun1)1) School of Materials and Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China2) Department of Materials
,
School of Mechanical Engineering
,
Shenyang University
,
Shenyang 110044
,
China
金属学报(英文版)
Using yttriu m nitrate as the m other salt , synthesis of ultrafine yttria po w der through w et che mical route w as investigated . Choice of precipitant has dra m atic effects on co m position ,particle size distribution and particle m orphology of the precipitates . When a m m onia solutionw as used as the precipitant , the precursor precipitate w as m ainly Y2( O H) 5 14( N O3) 0 86· H2 O with co m paratively large particle size , broad size distribution and co m plex particleshapes . When sodiu m hydroxide solution w as used , roughly spherical α Y( O H)3·3 H2 Opre cipitate w ith sm all particle size and narro w size distribution w as obtained . The transfor m a tion sequence of dry α Y( O H)3 ·3 H2 O gel during calcination w as determ ined to be α Y( O H) 3·3 H2 O→ Y O O H→ Y2 O3 . After calcining at 600 ℃ for 1 hour , both Y2( O H) 5 14( N O3) 0 86· H2 O and α Y( O H) 3·3 H2 O transfor m to well crystallized Y2 O3 pow ders ,w ith particle sizes of 50 ～3000 n m and 20 n m , respectively .
关键词:
KEYW ORDS yttria
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null
,
null
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null
Shaoxiong ZHOU
材料科学技术（英文）
The discovery of the first Fe-based ferromagnetic amorphous alloy in 1966 had made an impact on conventional magnetic materials because of its unique properties. Since then, a number of amorphous magnetic materials have been successfully developed and used in a wide variety of applications. A brief review of R & D activities on amorphous soft magnetic materials in China is given from the beginning to the present in a somewhat chronological order, followed by a brief introduction to their applications on electric and electronic industries. An analysis and a prospect of Chinese market of such amorphous materials are also presented.
关键词:
QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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null
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null
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null
SUN Wenqiang
,
CAI Jiuju
,
MAO Hujun
,
GUAN Duojiao
钢铁研究学报(英文版)
As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide (CO2) emissions, the China′s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use. The logarithmic mean Divisia index (LMDI) technique is used to decompose total change in CO2 emissions into four factors: emission factor effect, energy structure effect, energy consumption effect, and steel production effect. The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions; whereas the energy consumption effect contributes most to the reduction in CO2 emissions. And the emission factor effect makes a weak negative contribution to the increase of CO2 emissions. To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions, the correlation equations are also proposed.
关键词:
CO2 emissions
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energy use
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LMDI technique
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steel production
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energy consumption
American Mineralogist
A natural high-pressure phase of titanium oxide with alpha-PbO2-structure has been found in omphacite from coesite-bearing eclogite at Shima in the Dabie Mountains, China. High-resolution transmission electron microscope observations have revealed an orthorhombic lattice, corresponding to alpha-PbO2-type TiO2, with cell parameters a = 0.461 nm, b = 0.540 nm, c = 0.497 nm and space group Pbcn. It occurs as nanometer-thick (< 2 nm) lamellae between multiple twinned rutile crystals, providing additional evidence of very high-pressure, metamorphism at 7 GPa, 900 degrees C. This implies subduction of continental material to a depth of more than 200 kilometers. alpha-PbO-type TiO2 could be an extremely useful index mineral for ultrahigh-pressure.
关键词:
high-pressure phase;ries crater;rutile;polymorph;titanium
CAI Jiuju
,
LU Zhongwu
,
YUE Qiang
钢铁研究学报(英文版)
The industrial system should learn from the natural ecosystem. The resource utilization efficiency should be increased and the environmental load should be decreased, depending on the materials recycled in the system. The classification of industrial materials from the viewpoint of largescale recycling was stated. Recycling of materials, on three different levels, was introduced in the industrial system. The metal flow diagram in the life cycle of products, in the case of no materials recycled, materials partially recycled, and materials completely recycled, was given. The natural resource conservation and the waste emission reduction were analyzed under the condition of materials completely recycled. The expressions for the relation between resource efficiency and material recycling rate, and the relation between ecoefficiency and material recycling rate were derived, and the curves describing the relationship between them were protracted. The diagram of iron flow in the life cycle of iron and steel products in China, in 2001, was given, and the iron resource efficiency, material recycling rate, and iron ecoefficiency were analyzed. The variation of iron resource efficiency with the material recycling rate was analyzed for two different production ratios.
关键词:
recycling;industrial material;product life cycle;resource efficiency;ecoefficiency;material recycling rate
