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Influence of nanometric CeO2 coating on high temperature oxidation of Cr

Progress in Natural Science:materials international 2007年第5期17卷 601-606页

作者： Jin Huiming , Zhang Linnan and Liu Xiaojun (materials Research center, Department of Mechanical Engineering, Yangzhou University, Yangzhou 225009, china College of materials Science and Engineering, North-East University, shenyang 110014, china) materials Research center Department of Mechanical Engineering Yangzhou University Yangzhou 225009 China Laboratoire de magnetisme Louis Neel 25 avenue des Martyrs 38042 Grenoble cedex 9 France

Isothermal and cyclic oxidation behavior of chromium and its superficially applied nanometric CeO2 samples were studied at 900℃in air. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and high resolution electronic microscopy (HREM) were used to examine the morphology and micro-structure of oxide films. It was found that ceria addition greatly improved the anti-oxidation ability of Cr both in isothermal and cyclic oxidizing experiments. Acoustic emission (AE) technique was used in situ to monitor the cracking and spalling of oxide films, and AE signals were analyzed in time-domain and number-domain according to the related oxide fracture model. Laser Raman spectrometer was also used to study the stress status of oxide films formed on Cr with and without ceria. The main reason for the improvement in anti-oxidation of chromium was that ceria greatly reduced the growing speed and grain size of Cr2O3. This fine-grained Cr2O3 oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained the ridge character and relatively low internal stress level. Meanwhile, ceria application reduced the size and the number of interfacial defects, while remarkably enhanced the adhesive property of Cr2O3 oxide scale formed on Cr substrate.

关键词： oxidation stress CeO2 nanoparticle coating chromium.

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Microstructure and Mechanical Properties of Dy-α-sialon/Nano-size SiC Composites

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Journal of materials Science & Technology 1997年第4期13卷 336-338页

作者： Danyu JIANG Chen ZHANG Jianlin SHI Tingrong LAI and Dongsheng YAN(Shanghai Institute of Ceramics, chinese academy of sciences, Shanghai 200050, china) Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

The composite of Dy-α-sialon/10 wt pct nano-size SiC particles has been prepared from precursor powders of Si3N4, AIN, Al2O3, Dy2O3 and nano-size β-SiC. The hardness, toughness and bending strength of the composite at ambient temperature are a little higher than those of Dy-α-*** the bending strength is maintained up to 1000℃ and about 2 times more than that of Dy-α-sialon at the same temperature. The fracture surfaces show that the grain size of the composite is smaller than that of Dy-α-sialon, and both Of them have predominately transgranular mode of fracture. It is believed that the decrease of the bending strength of Dy-α-sialon at elevated temperature is caused by the viscous flow of the grain boundary phase, while the addition of nanosize SiC particles effectively increases the viscosity of the grain boundary phase and therefore prevents the strength loss of Dy-α-sialon/nano-size SiC composites at elevated temperature

关键词： Microstructure and Mechanical Properties of Dy sialon/Nano-size SiC Composites SiC Nano

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Seasonal variation of global stratosphere-troposphere mass exchange

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Progress in Natural Science:materials international 2007年第12期17卷 1466-1475页

作者： Guo Dong1,2, Lu Daren2 and Sun Zhaobo1(1. Institute of Atmospheric sciences, Nanjing University of Information Science and Technology, Nanjing 210044, china 2. LAGEO, Institute of Atmospheric physics, chinese academy of sciences, Beijing 100029, china) Institute of Atmospheric sciences Nanjing University of Information Science and Technology Nanjing 210044 China LAGEO Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

By Wei formula in pressure coordinate, the stratosphere-troposphere mass exchange (STME) is diagnosed globally for 44 years from 1958 to 2001 using the European center for Medium-Range Weather Forecasts (ECMWF) reanalysis datasets. Regions of mass flux into the stratosphere are found over Indonesia, bay of Bangladesh and the mid-west coast of South Africa. Compensating mass outflow from the stratosphere appears mainly over mid-latitudes near large-scale troughs. Upward and downward transport of mass at the middle and high latitudes accompany with each other. Mass flux into troposphere is stronger in autumn and winter than in spring and summer. Strong downward mass flux into the troposphere occurs in eastern Asia the whole year with nearly stable sites. Although the area of eastern Asia accounts for only 5.6% of that of the northern hemisphere (NH), its net mass exchange reaches 15.83% of that of the NH, which means that research on STME of eastern Asia is greatly important to that of the NH and even the global areas. Air across the tropopause enters more from stratosphere to troposphere than that from troposphere to stratosphere, which is possibly related with systematic bias of the assimilated datasets and with persistent rise of the tropopause height. Contributions of the mass exchange and the mass flux exchange in the NH and southern hemisphere (SH) on their latitudes increase from equator to pole, with larger contributions in the NH. Mass exchange and mass flux exchange per areas at high latitudes are larger than that at low latitudes, which means greater mass exchange efficiency at high latitudes.

关键词： stratosphere troposphere mass exchange seasonal variation.

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Pressure-induced crystallite breaking in La_(0.7)Sr_(0.3)Mn_(0.9)Fe_(0.1)O_3 nanosolids

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chinese Science Bulletin 1998年第6期43卷 458-461页

作者： ZHENG Fanlei 1, 2, SUI Yu 1, 3, XU Dapeng 1 and SU Wenhui 1, 4 1. Department of physics, Jilin University, Changchun 130023, china 2. Changchun Institute of physics, chinese academy of sciences, Changchun 130021, china 3. Institute of Metal R Department of physics Jilin University Changchun Chinas Changchun Institute of physics Chinese Academy of Sciences Changchun China Institute of Metal Research Chinese Academy of Sciences Shenyang China international center for materials physics Chinese Academy of Sceinces Shenyang China center for Condensed Matter and Radiation physics CCAST (World Lab.) Beijing China

In the compacting process of the La 0.7Sr 0.3Mn 0.9Fe 0.1O 3 nanosolids under the pressure range of 0.0-4.5 GPa, the apparent pressure-induced crystallite breaking phenomenon in these nanosolids was observed. With increasing pressure up to 4.5 GPa, the average grain size decreases by 46% while the magnetization of nanosolids decrease by 40% and their coercive increases by 35%. This kind of breaking has a close relation to the existence of oxygen deficiency in La 0.7Sr 0.3Mn 0.9Fe 0.1O 3 nanoparticles. A simple and convenient method for preparing the bulk nanosolids with a large number of clean interfaces has been suggested.

关键词： nanosolid pressure-induced breaking high pressure.

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EFFECT OF VANADIUM DOPING ON SUPERCONDUCTIVITY AND GLASS FORMING ABILITY OF Bi BASED SUPERCONDUCTORS

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Acta Metallurgica Sinica(English Letters) 1999年第4期12卷 485-487页

作者： Y. Zhuo1) , M. Gao1 ,2)and J.Y. Chen1,3) 1) Department of physics,shenyang Normal College,shenyang 110031 ,china2) Institute of Metal Research , The chinese academy ofsciences,shenyang 110015 ,china 3) international centerfor materials physics,CAS,Sheny

BiVxSrCaCu2 Oysystem glasses were prepared by using doubleroller quenching method. Thedifferentialthermal analysis was employed to investigate the effect of V doping on glass forming ability( GFA). Theresultsshowedthatthe GFAof Bisystem increases withthein creasing ofthe amountof Vdoping. Thebestatomic ratiofor having both superconductivityandthegreatest GFAwas BiV0 18 CaCu2 Oy .

关键词： analysis Bisystem glass Bi based high TCsuperconductors differentialthermal

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Nonlinear Excitation and Dynamic Features of Deoxyribonucleic Acid (DNA) Molecules

Nonlinear Excitation and Dynamic Features of Deoxyribonuclei...

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2008年全国生物化学与分子生物学学术大会

作者： Xiao-feng Pang (Institute of Life Sceinee and Yechnplogy,University of Electronic Science and Technology of china,Chengdu 610065,P.R.china international center for materials physics,chinese academy of sciences,shenyang 110015)

The structure of DNA and its biological function have been one of the most fascinating problem of modern biophysics,much attentions to it have been paid up to now because it is at the basis of *** idea that nonlinear ...

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ZrO2 strengthened NiAl/Cr(Mo,Hf) composite fabricated by powder metallurgy

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Progress in Natural Science:materials international 2012年第3期22卷 231-236页

作者： L.Y. Sheng a,b, J.T. Guo c, T.F. Xi a,b, B.C. Zhang c, H.Q. Ye c a PKU-HKUST ShenZhen-Hong Kong Institution, Shenzhen 518057, china b College of Engineering, Peking University, Beijing 100871, china c Institute of Metal Research, chinese academy of sciences, shenyang 110016, china PKU-HKUST ShenZhen-Hong Kong Institution College of Engineering Peking University Institute of Metal Research Chinese Academy of Sciences

The ZrO2 ceramic particles strengthened NiAl/Cr(Mo,Hf) composite was fabricated from the rapidly solidified NiAl/Cr(Mo,Hf) pre-alloyed powder and the ZrO2 powder by powder metallurgy technique. Microstructure examination revealed that in the prepared composite NiAl and Cr(Mo) phases distributed at the eutectic cell boundary become coarse but many Cr(Mo) platelets inside the eutectic cell were broken, which was different from the original powder. Moreover, fine Ni2AlHf and Hf solid solution particles distributed uniformly in the composite, and the ZrO2 particles mainly segregated along eutectic cell boundary. In addition, twin crystal and stacking faults were observed inside of ZrO2 grains. The experimental results showed that the ZrO2 ceramic particles strengthened NiAl/Cr(Mo,Hf) composite exhibited better room temperature and high temperature mechanical properties than the NiAl/Cr(Mo,Hf) alloy, which may be attributed to the fine structure and the strengthening effect of ZrO2 particles.

关键词： NiAl intermetallics NiAl/Cr(Mo) composite Powder metallurgy ZrO2 strengthening

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STRUCTURE OF Al-Mn-Zn-Mg ALLOY POWDER

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Acta Metallurgica Sinica(English Letters) 1996年第2期9卷 79-84页

作者： WU Lijun ZHAO Lihua YANG Qiaoqin LI Shaolu LI Xieqian(materials Research and Test Centre,Hunan University,Changsha 410082,china)(Laboratory of Atomic Imaging of Solids,Institute of Metal Research, chinese academy of sciences,shenyang 110015,china)

The structure of Al-Mn-Zn-Mg alloy powder annealed at 800℃ has been studied by transmisston electron microscopy(TEM).An approximant phase(named as C-phase) to the decagonal phase was found and its crystal structure was determined It belongs to c-center orthorhombic lattice with a=2.35 nm,b=3.27 nm and c=1.22 *** stillfound a hexagonal phase with a=0.7) nm and c=0.79 nm,(named as phase) in the annealed alloy *** annealed alloy powder is composed of the C-phase,the phase,the decagonal phase and Al solid solution.

关键词： quasicrystal crystalline structure Al-Mn-Zn-Mg alloy powder

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Study on Sulfide-melt Inclusions in Mantle Xenoliths of Xinchang, Zhejiang

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international Journal of Minerals,Metallurgy and materials 2000年第1期14卷 5-9页

作者： Jiuhua Xu Xuelei Chu YulingXie Fenglei Bie Dayi Qian University of Science and Technology Beijing, Beijing 100083, china china University of Geosciences, Beijing 100083, china The Research center of Mineral Resources Exploration, chinese academy University of Science and Technology Beijing Beijing 100083 China Research center of Mineral Resources Exploration Chinese Academy of Sciences Beijing 100101 China Institute of Geology Chinese Academy of Sciences Beijing 100029 China china University of Geosciences Beijing 100083 China

In minerals of mantle xenoliths captured within Tertiary alkali-basalt from Xinchang, Zhejiang province, china, many sulfidemelt inclusions were found by the observation of polished thin section. Electron microprobe analysis has been applied to detect the components of sulfide-melt inclusions. The result shows that the sulfide phases of inclusions are mainly pentlandite, and secondarily pyrrho- tite, The molar ratio of Ni to Fe, r_Ni,/r_Fe, of mineral phases in sulfide inclusions is related to olivine contents in host mantle xenoliths. The r_Ni/r_Ni, of sulfides from Xinchang samples has a possitive correlation to r_(Fe+Ni),/r_S. The r_(Fe+Ni),/r_S, becomes higher with the increasing of r_Ni/r_Fe In single sulfide-melt inclusions, r_Ni,/r_Fe, r_(Fe+Ni),/r, and Ni contents increase from the center to edge, reflecting a result of different cooling speed in an inclusion. A comparison between the data from Hannuoba, West Eifel of Germany and Nograd-Gomor of east Europe suggests that the composition of the inclusions is different for each area, which indicated that a regional differentiation of sulfide in mantle fluids.

关键词： mantle xenolith sulfide-melt inclusion electron microprobe analysis, Xinchang

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PLS path model building:A multivariate approach to land price studies-A case study in Beijing

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Progress in Natural Science:materials international 2009年第11期19卷 1643-1649页

作者： Wenjie Wu~(a,b),Wenzhong Zhang~(a,*) a Institute of Geographic sciences and Natural Resources Research,CAS,Beijing 100101,china b Graduate University of chinese academy of sciences,Beijing 100049,china Institute of Geographic sciences and Natural Resources Research CAS Beijing 100101 China Graduate University of chinese academy of sciences Beijing 100049 China

Previous studies have revealed that statistical methods can be used to analyze land-leasing parcel ***,the conventional statistical methods used in land analysis have some limitations,especially in cases of limited observational *** this paper,with the help of geographic information system(GIS) techniques,a partial least squares(PLS) path model is applied to study the relationship between residential land prices and various determinants through a case study of Beijing in *** a preliminary analysis,four latent variables are selected:accessibility of the workplace center,livability,traffic,and environment *** results show that the observation variables have a strong explanatory power for their corresponding latent variables,and the four latent variables have varying impacts on residential land *** the latent variables,accessibility to the workplace center has the strongest impact on the residential land price.

关键词： Land PLS path model GIS Beijing

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