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Comparison of dark energy models:A perspective from the latest observational data

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中国科学：物理学、力学、天文学英文版 2010年第9期53卷 1631-1645页

作者： LI Miao1,2.LI XiaoDong2.3.& ZHANG Xin1,4 1Kavli institute for {3. Physics {2.,Chinese academy of sciences,beijing 100190,{2. 2.ey laboratory of frontiers in {3. Physics,institute of {3. Physics,Chinese academy of sciences,beijing 100190,{2. 3.nterdisciplinary Center for {3. Study,University of Science and Technology of {2.,Hefei 2.002.,{2. 4Department of Physics,College of sciences,Northeastern University,Shenyang 110004,{2. Kavli institute for theoretical Physics {2. Chinese Academy of Sciences Beijing China Key laboratory of {2. in {3. Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing China Interdisciplinary Center for theoretical Study University of Science and Technology of China Hefei China Department of Physics College of Sciences Northeastern University Shenyang China

We compare some popular dark energy models under the assumption of a flat universe by using the latest observational data including the type Ia supernovae Constitution compilation,the baryon acoustic oscillation measurement from the Sloan Digital Sky Survey,the cosmic microwave background measurement given by the seven-year Wilkinson Microwave Anisotropy Probe observations and the determination of H0 from the Hubble Space *** comparison statistics such as the Bayesian and Akaike information criteria are applied to assess the worth of the *** statistics favor models that give a good fit with fewer *** on this analysis,we find that the simplest cosmological constant model that has only one free parameter is still preferred by the current *** other dynamical dark energy models,we find that some of them,such as the αdark energy,constant w,generalized Chaplygin gas,Chevalliear-Polarski-Linder parametrization,and holographic dark energy models,can provide good fits to the current data,and three of them,namely,the Ricci dark energy,agegraphic dark energy,and Dvali-Gabadadze-Porrati models,are clearly disfavored by the data.

关键词： dark energy models observational constraints model comparison information criteria

A first-principles investigation into the hydrogen bond interaction in β-HMX

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Science china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1080-1085页

作者： CHEN Fang 1 ,ZHANG Hong 1,2.ZHAO Feng 3.,MENG ChuanMin 3.& CHENG XinLu 1 1 institute of Atomic and Molecular Physics,Sichuan University,Chengdu 610065,china 2.School of Physical Science and Technology,Sichuan University,Chengdu 610065,china 3.laboratory for Shock Wave and Detonation Physics Research,Southwest institute of Fluid Physics,china academy of Engineering Physics,Mianyang 62.900,china institute of Atomic and Molecular Physics Sichuan University Chengdu China School of Physical Science and Technology Sichuan University Chengdu China laboratory for Shock Wave and Detonation Physics Research Southwest Institute of Fluid Physics China Academy of Engineering Physics Mianyang China

A theoretical study of structural and electronic properties of β-HMX crystal is performed using density-functional theory(DFT). The total density of states(TDOS) is presented. The atomic orbit projected density of state(PDOS) from the p-type orbit of C,N,O and the s-type orbit of H is discussed. The study by analyzing the PDOS shows that the structure of β-HMX crystal possesses C-H···O intra- and inter-molecular hydrogen-bonding. There exists a hydrogen bonding between H5 -1s and O12.-2. orbits,between H19 -1s and O2. -2. orbits of intra molecules,and between H19 -1s and O2. -2. orbits of inter molecules. The Mulliken population analysis is also made.

关键词： structural property hydrogen bond β-HMX population analysis

Effect of Carbon and Sulfur on Iron Melting at High Pressure:Implications for Composition and Evolution of the Planetary Terrestrial Cores

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地学前缘 2009年第S1期16卷 204-204页

作者： L.W.Deng~1,Y.W.Fei~2.X.Liu~1,Z.Z.Gong~3.1.School of Earth and Space Science,Peking University,beijing 100871,china. 2.Geophysical {2.,Carnegie Institution of Washington,52.1 Broad Branch Road,NW,DC 2.015,USA 3.institute of Spacecraft Environment Engineering,beijing 100094,china

The presence of light element(s)in the Earth’s core is necessary in order to explain the observed density and velocity discrepancy for the core(Anderson and Ahrens,1994).O,Si,S,C and H were suggested as potential candidates based on cosmochemical considerations(Stevenson,1981).High-pressure experiment results,in conjunction with theoretical and cosmochemical evidences,argued that it is difficult for any one of them to account for the core

关键词： sulfur-carbon-iron high pressure melting planetary core

The variation of transition location in response to the variation of the amplitudes of initial disturbances

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Science china(Physics,Mechanics & Astronomy) 2010年第6期53卷 1109-1115页

作者： SU CaiHong & ZHOU Heng Department of Mechanics,Tianjin University,Tianjin 3.0072.china Department of Mechanics Tianjin University Tianjin China

The transition location of a boundary layer depends on the amplitude and characteristic of initial disturbances. The larger the amplitude and the amplification rate of the initial disturbances are,the more upstream the transition location is. However,the environment surrounding the flying vehicle is variable,so the amplitude and characteristic of the disturbances triggered in the boundary layer through receptivity are also variable. In this paper,how the transition location varies in response to the variation of the initial disturbance amplitudes is studied by using direct numerical simulation. The results show that if the initial disturbance amplitudes become smaller,the transition location moves downstream correspondingly,but there is a time delay compared to the time of arrival of the disturbances with reduced amplitudes. Moreover,the speed of moving downstream is appreciably lower than the propagation speed of the disturbances. On the other hand,if the amplitudes of the initial disturbances recover their original value,the transition would immediately take place whenever the disturbances reach the former transition location,but the laminar flow between the new and old transition locations would not become turbulent immediately. theoretical explanations are provided based on the transition mechanism found by our group.

关键词： transition boundary layer stability modification of mean flow direct numerical simulation

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国际汉学研究的新发展与比较文学的前景

四川外语学院学报 2001年第1期17卷 1-2页

作者：乐黛云北京大学北京 100871

随着经济、科技全球化和文化多元化的发展 ,原来互不相干的三个学术圈子 :汉学研究、理论研究、比较文学研究正在迅速靠拢 ,并实现互补、互识、互证。这样的深刻变化和新形势 ,为中国比较文学的发展提供了崭新的前景。首先 ,由于新汉学... 详细信息

随着经济、科技全球化和文化多元化的发展 ,原来互不相干的三个学术圈子 :汉学研究、理论研究、比较文学研究正在迅速靠拢 ,并实现互补、互识、互证。这样的深刻变化和新形势 ,为中国比较文学的发展提供了崭新的前景。首先 ,由于新汉学家对比较文学的介入 ,必将大大促进和加深西方文化与中国文化的互看和互相照亮 ;其次 ,西方主流理论家逐渐开始关注文化的多元发展问题 ,他们正在从西方中心论中走出来 ,试图了解他种文明 ,并将多种文化铸入自己的理论中 ,这种理论上的新探索必将大大加强比较文学的理论基础 ;第三 ,异质文化之间的比较研究将取代过去局限于同质文化中不同地区文化的比较研究 ,这就必然会大大开拓比较文学学科的学术视野。

关键词：文化多元化国际新汉学比较文学

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射电星

天文学进展 1987年第4期 289-299页

作者：刘绪昭中国科学院北京天文台

本文介绍了射电星研究的发展过程和恒星射电天体物理的初步知识,并按如下四个方面评介了射电星观测研究最前沿的成果:星风的射电辐射(OB型星,沃尔夫-拉叶星,早型发射线星,共生星,金牛T型星,晚型巨星和超巨星);活动双星和dMe型星(猎犬RS... 详细信息

本文介绍了射电星研究的发展过程和恒星射电天体物理的初步知识,并按如下四个方面评介了射电星观测研究最前沿的成果:星风的射电辐射(OB型星,沃尔夫-拉叶星,早型发射线星,共生星,金牛T型星,晚型巨星和超巨星);活动双星和dMe型星(猎犬RS型星,dMe型星,大陵五,激变变星,大熊W型星,活动超巨星);X射线星;新星和超新星。为了更好地理解观测结果,文中也介绍了初步的理论解释。

关键词：射电辐射射线源射电星特殊天体星风射电光度射电波段非热辐射电磁辐射恒星辐射机制