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Spin-glass like behaviors in La_(1-x)Tb_xMnO_3 perovskite

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Science China(physics,Mechanics & Astronomy) 2009年第12期52卷 1893-1897页

作者： ZHANG YingTang1,2.3,WANG ChunChang2.4,LIU WeiBin1,WANG Zhong3,LU HuiBin2.& CHEN ZiYu1 1 Department of physics,beijing University of Aeronautics and Astronautics,beijing 100191 2.institute of physics & Center for condensed matter physics,chinese academy of sciences,beijing 100190 3 School of Material Science & Engineering,Shaanxi University of Technology,Hanzhong 72.003 4 institute of Superconducting and Electronic Materials,Wollongong University,Northfield Ave,Gwynneville,NSW 2.2.,Australia Department of physics Beijing University of Aeronautics and Astronautics Beijing China institute of physics & Center for condensed {2. physics Chinese Academy of Sciences Beijing China School of Material Science & Engineering Shaanxi University of Technology Hanzhong China institute of Superconducting and Electronic Materials Wollongong University Gwynneville Australia

A series of samples of La1-xTbxMnO3 (0≤x≤0.15) are prepared. The static and dynamic magnetizations of La1-xTbxMnO3 have been investigated. The results indicate that the spins with the short-range order are frozen into random direction at low enough temperatures which leads to the samples exhibiting the spin-glass like behavior. It is considered that the spin-glass like behavior originates from the competition between ferromagnetic double exchange among Mn3+ and Mn2. and antiferromagnetic superex-change among Mn3+ and Mn3+,as well as Tb3+ and Tb3+.

关键词： La1-xTbxMnO3 spin-glass-like behavior short-range order

Characterization of plastic flow in two Zr-based bulk metallic glasses

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Science China(Technological sciences) 2006年第4期49卷 414-424页

作者： XING Dongmei1,2. ZHANG Taihua1, LI Weihuo3 & WEI Bingchen3 1. State Key laboratory of Nonlinear Mechanics (LNM), institute of Mechanics, {2. academy of Sci- ences, beijing 100080, China 2. College of physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074, China 3. national Microgravity laboratory, institute of Mechanics, chinese academy of sciences, beijing 100080, China State Key laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing China College of physics and Electronic Information Science Tianjin Normal University Tianjin China national Microgravity laboratory Institute of Mechanics Chinese Academy of Sciences Beijing China

Plastic deformation behaviors of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses (BMGs) are studied by using the depth-sensing nanoindentation, microindentation and uniaxial compression. The Be-containing BMG exhibits a signifi- cantly improved overall plastic strain compared with the Be-free alloy during compressive tests. Both BMGs show a loading-rate-dependent serrated flow during nanoindentation measurements, but the Be-containing alloy exhibits a much lower critical loading rate for the disappearance of the serration than the Be-free BMG. The shear band patterns de- veloped during plastic deformation are investigated by microindentation technique, wherein much higher shear band density is found in the Be-containing alloy than in the Be-free alloy, indicating an easier nucleation of shear bands in the former BMG. The dif- ference in the plastic deformation behavior of the two BMGs can be explained by a free volume model.

关键词： Bulk metallic glass, plastic deformation, shear band, nanoindentation.

Spectroscopic study of globular clusters in the halo of M31 with the Xinglong 2.16 m telescope

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Research in Astronomy and Astrophysics 2011年第11期11卷 1298-1310页

作者： Zhou Fan1,2.Ya-Fang Huang1,2.Jin-Zeng Li1,2.Xu Zhou1,2.Jun Ma1,2.Hong Wu1,2.Tian-Meng Zhang1,2.and Yong-Heng Zhao1,2.1 national Astronomical Observatories,chinese academy of sciences,{2. 100012.China 2.Key laboratory of Optical Astronomy,national Astronomical Observatories,chinese academy of sciences,{2. 100012.China national Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present spectroscopic observations for 11 confirmed globular clusters(GCs) of M31 with the OMR spectrograph on the 2.16 m telescope at the Xinglong site of national Astronomical Observatories,chinese {2. of *** of our sample clusters are located in the halo of M31 and the most remote one is out to a projected radius of 78.75 kpc from the galactic *** all our sample clusters,we measured the Lick absorption-line indices and radial *** is noted that most GCs in our sample are distinct from the HI rotation curve of galaxy M31,especially for B514,MCGC5,H12.and B517,suggesting that most of our sample clusters do not have a kinematic association with the star-forming young disk of the *** separately fitted the absorption line indices from the updated stellar population model of Thomas et *** two different tracks of Cassisi and Padova,by applying the χ2.minimization *** fitting results show that all our sample clusters are older than 10 Gyr,and metal-poor(2.38 ≤ [Fe/H] ≤ 0.91 dex).After merging the spectroscopic metallicity of our work with the previously published ones,we extended the cluster sample out to a projected radius of 117 kpc from the galaxy's *** found the metallicity gradient exists for all the confirmed clusters with a slope of 0.02. ± 0.001 dex kpc ***,the slope turns out to be 0.018 ± 0.001 dex kpc 1 for all the halo clusters,which is much *** we only consider the outer halo clusters with rp > 2. kpc,the slope becomes 0.010 ± 0.002.dex kpc 1 and if one cluster G001 is excluded from the outer halo sample,the slope is 0.004 ± 0.002.dex kpc ***,we conclude that the metallicity gradient for M31's outer halo clusters is not significant,which agrees well with previous findings.

关键词： galaxies individual(M31) — galaxies star clusters — globular clusters general — star clusters general

Variations of δ^(18)O in precipitation from the Muztagata Glacier, East Pamirs

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Science China Earth sciences 2006年第1期49卷 36-42页

作者： LI Zhen1, YAO Tandong1,2. TIAN Lide1,2. XU Baiqing1,2.& Wu Guangjian2.1. Key laboratory of Cryosphere and Environment, Jointly Established by Cold and Arid Regions Environmental and Engi-neering Research institute and institute of Tibetan Plateau Research, chinese academy of sciences and chinese academy of Meteorological sciences, China Meteorological Administration, CAS, Lanzhou 730000, China 2. laboratory of Environment and Process on Tibetan Plateau, institute of Tibetan Plateau Research, chinese academy of sciences, beijing 100085, China Key laboratory of Cryosphere and Environment Jointly Established by Cold and Arid Regions Environmental and Engineering Research Institute and Institute of Tibetan Plateau Research Chinese Academy of Sciences and Chinese Academy of Meteorological Sciences China Meteorological Administration Lanzhou China laboratory of Environment and Process on Tibetan Plateau Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing China

Expeditions to Muztagata (in the eastern Pamirs) during the summer seasons of2.02.and 2.03 collected precipitation samples and measured their oxygen isotopes. The δ^(18)O inprecipitation displays a wide range, varying from -17.40per thousand to +1.33per thousand inJune—September 2.02.and from -2..31per thousand to +4.59per thousand in May—August 2.03. Theδ^(18)O in precipitation correlates with the initial temperature of precipitation during theobserving periods. The positive correlation between δ^(18)O and temperature suggests that δ^(18)Ocan be used as an indicator of temperature in this region. The δ^(18)O values in fresh-snow samplescollected from two snow events at different elevations on the Muztagata Glacier show a strong''altitude effect'', with a ratio of nearly -0.40per thousand per 100 m from 5500 m to 7450 m.

关键词： Muztagata, δ18O, temperature, altitude effect.

Monaural voiced speech segregation based on elaborate harmonic grouping strategies

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Science China(Information sciences) 2011年第12期54卷 2491-2500页

作者： LIU WenJu 1 , ZHANG XueLiang 1 , JIANG Wei 1 , LI Peng 2.& XU Bo 2.1 national laboratory of Pattern Recognition, {2. of Automation, chinese academy of sciences, beijing 100190, China 2.Digital Media Content Technology Research Center, {2. of Automation, chinese academy of sciences, beijing 100190, China national laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing China Digital Media Content Technology Research Center Institute of Automation Chinese Academy of Sciences Beijing China

In this paper, an enhanced algorithm based on several elaborate harmonic grouping strategies for monaural voiced speech segregation is proposed. Main achievements of the proposed algorithm lie in three aspects. Firstly, the algorithm classifies the time-frequency (T-F) units into resolved and unresolved ones by carrier-to-envelope energy ratio, which leads to more accurate classification results than by cross-channel correlation. Secondly, resolved T-F units are grouped together according to minimum amplitude principle, which has been verified to exist in human perception, as well as the harmonic principle. Finally, "enhanced" envelope autocorrelation function is employed to detect amplitude modulation rates, which helps a lot in reducing half-frequency error in grouping of unresolved units. Systematic evaluation and comparison show that performance of separation is greatly improved by the proposed algorithm. Specifically, signal-to-noise ratio (SNR) is improved by 0.96 dB compared with that of previous method. Besides, our algorithm is also effective in improving the PESQ score and subjective perception score.

关键词： computational auditory scene analysis voiced speech separation harmonistic principle minimum amplitude principle elaborate harmonic grouping strategies

Exploration of combined adjustment laws about IGV,stator and rotational speed in off-design conditions in an axial compressor

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中国科学：技术科学英文版 2010年第4期53卷 969-975页

作者： HU YanMing1,2.& NIE ChaoQun1 1 Key laboratory of Advanced Energy and Power Technology,institute of Engineeting Thermo{2.,chinese academy of Science,beijing 100190,China 2.Graduate School of chinese academy of sciences,beijing 100190,China Key laboratory of Advanced Energy and Power Technology Institute of Engineeting Thermophysics Chinese Academy of Science Beijing China Graduate School of chinese academy of sciences Beijing China

Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes(IGV) and adjustable *** characteristics of the compressor,especially the efficiency and stall margin,are analyzed in design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational *** experimental results show that the off-design performance of the multistage axial compressor is improved by restaggering of IGV and stators related to rotational *** the background of engineering applications,digital signal processing(DSP) technique is used to realize online adjustment of stagger angles according to the corresponding relations between incidence angles of rotor and rotational speed.

关键词： axial compressor IGV surge DSP techniques off-design

The correspondence between the concepts in description logics for contexts and formal concept analysis

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Science China(Information sciences) 2012年第5期55卷 1106-1122页

作者： MA Yue 1,2.SUI YueFei 1 & CAO CunGen 1 1 Key laboratory of Intelligent Information Processing,institute of Computing Technology,{2.,beijing 100190,China 2.Graduate University of {2.,beijing,China Key laboratory of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

Formal concept analysis (FCA) and description logic (DL) are meant to be formalizations of concepts.A formal concept in the former consists of its intent and extent,where the intent is the set of all the attributes shared by each object in the extent of the concept,and the extent is the set of all the objects sharing each property in the intent of the concept.A concept in the latter formalization is simply a concept name,the interpretation of which is a subset of a *** consider the correspondence between concepts in both formalizations,a multi-valued formal context must be represented both as a knowledge base and as a model of the DL for contexts,where concepts are decomposed into tuple concepts C,interpreted as a set of tuples and value concepts V,interpreted as a set of attribute-value *** show that there is a difference between the interpretation of concepts R.V /R.C and the Galois connection between the extent/intent of formal concepts in *** to the Galois connection,there should be concepts of the form + R.V and + R.C inter-preted in FCA,and hence the logical language L for DL is extended to be L + together with + as a constructor so that + R.V and + R.C are well-defined ***,according to the interpretation in DL there should be pseudo concepts in FCA so that the interpretation of concepts R.V /R.C is the extent/intent of pseudo *** correspondence between formal concepts and concepts in L +,and between pseudo concepts and concepts in L are presented in this paper.

关键词： description logic formal concept analysis concept attribute/role

Preparation and characterization of a novel adsorbent for removing lipophilic organic from water

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Science China Chemistry 2005年第6期48卷 600-604页

作者： LIU Huijuan1, DAI Ruihua1, QU Jiuhui1 & RU Jia1,2.1. State Key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental sciences, {2., beijing 100085, China 2. Graduate School of the {2., beijing 100039, China State Key laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing China Graduate School of the chinese academy of sciences Beijing China

A novel composite adsorbent containing a kind of lipid-triolein is studied. The ad-sorbent is prepared by embedding triolein into cellulose acetate (CA) sphere. The preparation method, the physical-chemical properties of the adsorbent and the removal efficiency of two or-ganochlorinated pesticides are studied. The adsorbent is stable in water and no triolein leaks into water for 465 h soaking. The adsorbent has high adsorption capacity for organochlorinated pes-ticides such as dieldrin and aldrin. The results suggest that triolein-containing adsorbent could serve as a good adsorbent for lipophilic organic pollutants. The adsorption rate for lipophilic pol-lutants is very fast and has relation with the logKow of the compounds.

关键词： triolein, cellulose acetate, adsorbent, lipophilic organic, drinking water.

MD simulation of the effect of contact area and tip radius on nanoindentation

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Science China(physics,Mechanics & Astronomy) 2004年第1期47卷 101-112页

作者： CHEN Shangda1,2.& KE Fujiu1,2.1. Department of Applied physics, beijing University of Aeronautics and Astronautics, beijing 100083, China 2. State Key laboratory of Non-linear Mechanics (LNM), institute of Mechanics, chinese academy of sciences, beijing 100080, China Correspondence should be addressed to Chen Shangda (email: chensd@***) Received August 2., 2.03 Department of Applied physics Beijing University of Aeronautics and Astronautics Beijing China State Key laboratory of Non-linear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing China

Molecular dynamics simulations of nanoindentation are performed on monocrystal copper. A new contact atoms method is presented for calculating the contact area. Compared with conventional methods, this method can provide the contact area more accurately not only for sink-in but also for pile-up situation. The effect of tip radius on indentation is investigated too. The results indicate that the measured hardness of the material will become higher as the tip radius increases.

关键词： nanoindentation, molecular dynamics, contact area, zero point of penetration depth, nano- hardness.