Rui Ding Chunxiang Xu Baoxiang Gu Zengliang Shi Haitao Wang Long Ba
材料科学技术（英文）
Well-crystallized MgZnO alloy thin films with hexagonal wurtzite structure were fabricated by sol-gel method. With the band gap increases, the surface roughness and the grain size reduces. It is worth noting that the intensity of the band-edge luminescence of Mg doped films enhances with the increase of the Mg content. The microstructure and photoluminescence mechanism have been discussed based on X-ray diffraction patterns, atomic force microscopy images, ultraviolet-visible absorption spectra, photoluminescence spectra and Fourier transform infrared spectra.
关键词:
null
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Optical properties
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Sol-gel method
Physical Review B
Longitudinal electron transport is investigated for a long-period semiconductor superlattice in the presence of a magnetic field applied along the growth direction of the superlattice. It is shown that the longitudinal magnetoresistance exhibits a complicated dependence on the magnetic-field strength. In contrast with the conventional Shubnikov-de Haas oscillations, the magnetoresistance shows periodic oscillations only in the region of low reciprocal magnetic field.
关键词:
magnetoresistance
王建生
,
韩其勇
,
魏寿昆
,
宋波
金属学报
应用Ba蒸气平衡法,在密封Mo反应室内,用自制的TiN和BaS坩埚,进行了纯Fe液中Ba—O,Ba—S,Ba—P平衡的研究。得到反应:BaO_(s)=[Ba]+[O]的标准自由能ΔG°_(wt-％)=188500+38.3T J/mol,e_O~(Ba)=624-1.25×10~6/TBaS_(S)=[Ba]+[S]的标准自由能ΔG°_(wt-％)=469100-111T J/mol,e_S~(Ba)=826-1.64×10~6/T1873K下,反应Ba_3P_2=3[Ba]+2[P]的K_(Ba_3P_2)=7.76×10~(-18),e_(Ba)~P=0.95,ΔG°_(wt-％)=613200 J/mol。
关键词:
Ba
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O
,
S
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P
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liquid iron
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thermodynamic parameters
F.M.Chu David P.Pope Dept.of Materials Science and Engineering
,
University of Pennsylvania
,
Philadelphia
,
PA 19104
,
USA
材料科学技术（英文）
In this paper the geometric description and general theory of mechanical twinning are reviewed, the twins in general lattices and superlattices are summarized, and the kinetic process by which mechanical twins form is revisited. A case study of mechanical twinning of HfV2+Nb, (cubic) Laves phase, is presented and the synchroshear of selected atomic layers is proposed to explain the physical process of twin formation. If the twins form in this way, then long shear vectors and / or atomicshuffles are not really necessary.
关键词:
twin
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null
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null
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null
J.M. Gong
,
S.T. Tu
,
J. Xia and X. Ling (School of Mechanical Engineering
,
Nanjing University of Chemical Technology
,
Nanjing 210009
,
China)
金属学报(英文版)
Creep deformation localization is generally found in structures at high temperamture,typically in weldments. As the heat affected zone (HAZ) in a weldment is very narrow, deformation in HAZ region can hardly be measured by conventional displacement gauge. A new method for measuring long-term local creep deformation was developed by quartz optical fiber and technique of digital image analysis. The creep deformations of base metal, weld metal and HAZ in weldments are thereby determined with crossweld specimens.
关键词:
creep deformation
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null
,
null
,
null
材料科学技术（英文）
A new type of long periodic structure has been found in ZrO2-Y2O3 ceramics in annealed states. High resolution electron microscopy (HREM), selected area electron diffraction, and computer simulation have been used to reveal the presence of the long periodic structure. The unit cell of the long periodic structure consists of a cubic ZrO2 unit cell and L1(0)- like phase one.
关键词:
ceramics;electron diffraction;electron microscopy;crystal structure;microstructure
Jiancun RAO
,
Yu ZHOU
,
Douxing LI
材料科学技术（英文）
A new type of long periodic structure has been found in ZrO2-Y2O3 ceramics in annealed states. High resolution electron microscopy (HREM), selected area electron diffraction, and computer simulation have been used to reveal the presence of the long periodic structure. The unit cell of the long periodic structure consists of a cubic ZrO2 unit cell and L10- like phase one.
关键词:
Ceramics
,
null
,
null
,
null
,
null
Applied Physics Letters
The dipole configuration of relaxor ferroelectrics (RFs) is investigated by numerically solving the time-dependent Ginzburg-Landau equation based on the dipole defect model. The domain structure of RFs is revealed to consist of dipole ordered clusters embedded in the paraelectric matrix. We demonstrate that the role of long-range elastic energy in RFs is much less important than in normal ferroelectrics, although the shape of the dipole clusters depends on the elastic energy. Based on the numerical results, a phase diagram of temperature-defect density for RFs is constructed, which identifies four distinct phase regimes. (c) 2006 American Institute of Physics.
关键词:
monte-carlo-simulation;dielectric-properties;computer-simulation;domain formation;defects;field;model;glass
