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Science china(physics,Mechanics & Astronomy) 2009年第7期52卷 1011-1020页

作者： GU Juan1,2, WANG ShanYing2 & GOU BingCong1 1 department of physics, beijing Institute of Technology, beijing 100081, china 2 department of physics, tsinghua university, beijing 100084, china department of physics Beijing Institute of Technology Beijing 100081 China department of physics Tsinghua University Beijing 100084 China

The geometrical structure, stability, magnetism, and electronic structure of bimetallic clusters AuM2 and Au2M2, where M are 4d transition metal elements, are investigated systematically by using the first-principles method based on density functional theory. The calculation results show that there is a large amount of low-energy isomers with the very similar structure. AuM2 and Au2M2 clusters display dramatic magnetism. The magnetic moment of the 4d element is either enhanced or weakened with respect to the bulk value, which is largely dependent on the orbital exchange-splitting.

关键词： density functional theory first-principles cluster electronic structure magnetism

New evidence for lack of CMB power on large scales

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 567-570页

作者： LIU Hao1 & LI TiPei1,2,3 1 Key Laboratory of Particle Astrophysics, Institute of High Energy physics, Chinese Academy of Sciences, beijing 100049, china 2 department of physics & Center for Astrophysics, tsinghua university, beijing 100084, china 3 department of Engineering physics & Center for Astrophysics, tsinghua university, beijing 100084, china 1. Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China2. Department of Physics & Center for Astrophysics Tsinghua University Beijing 100084 China3. Department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing 100084 China

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis

Calculation of light emission in sonoluminescence

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Science china(physics,Mechanics & Astronomy) 2009年第4期52卷 593-601页

作者： LI ChaoHui1 & AN Yu1,2 1 department of physics,tsinghua university,beijing 100084,china 2 Institute of Acoustics,Chinese Academy of Sciences,beijing 100190,china department of physics Tsinghua University Beijing 100084 China Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China

We modify a uniform model of single bubble sonoluminescence,in which heat diffusion,water vapor diffusion and chemical reactions are included to describe the bubble dynamics,and the processes of electron-atom bremsstrahlung,electron-ion bremsstrahlung and recombination radiation,radiative attachment of electrons to atoms and molecules,line emissions of OH radicals and Na atoms are taken into account to calculate the light emission. With this model,we compute the light pulse width,the photon number per flash,the continuum and line spectra and the gas species as the products of chemical reactions,and try to compare with all the experimental data available. We obtain good agreement with the observations of Ar and Xe bubbles in many cases,but fail to match the experimental data of the photon number per flash. We also find that for He bubble the computed photon number is always too small to interpret the observations.

关键词： sonoluminescence bremsstrahlung radiative attachment line spectrum collision broadening

Inconsistency between WMAP data and released map

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Chinese Science Bulletin 2010年第10期55卷 907-909页

作者： LIU Hao1 & LI TiPei1,2,3 1 Key Laboratory of Particle Astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,beijing 100049,china 2 department of physics & Center for Astrophysics,tsinghua university,beijing 100084,china 3 department of Engineering physics & Center for Astrophysics,tsinghua university,beijing 100084,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China department of physics & Center for Astrophysics Tsinghua University Beijing China department of Engineering physics & Center for Astrophysics Tsinghua University Beijing China

A remarkable inconsistency between the calibrated differential time-ordered data (TOD) of the Wilkinson Microwave Anisotropy Probe (WMAP) mission,which is the input for map-making,and the cosmic microwave background (CMB) temperature maps published by the WMAP team is revealed,indicating that there must exist a serious problem in the map making routine of the WMAP *** inconsistency is easy to be confirmed without the use of WMAP map-making *** view of the importance of this issue for cosmology study,we invite readers to check it by themselves.

关键词：威尔金森微波各向异性探测器 WMAP 地图制作宇宙微波背景有序数据制作软件 TOD CMB

The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus ^(52)Fe

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Science china(physics,Mechanics & Astronomy) 2009年第10期52卷 1471-1476页

作者： LI YanSong1,2 & LONG GuiLu1,2 1 department of physics,tsinghua university,beijing 100084,china 2 Center of Nuclear Theory,National Laboratory of Heavy Ion Accelerator of Lanzhou,Lanzhou 730000,china 1. department of physics Tsinghua University Beijing 100084 China 2. Center of Nuclear Theory National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

The relativistic consistent angular-momentum projected shell model(ReCAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus *** model calculations show a reasonably good agreement with the *** backbending at 12+ is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.

关键词： ReCAPS relativistic mean field angular-momentum projection method 52Fe neutron-proton interaction

Arbitrarily long distance quantum communication using inspection and power insertion

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Chinese Science Bulletin 2009年第1期54卷 158-162页

作者： WANG WanYing1,2,WANG Chuan1,2,ZHANG GuangYu1,3 & LONG GuiLu1,2 1 department of physics,tsinghua university,beijing 100084,china 2 tsinghua National Laboratory for Information Science and Technology,tsinghua university,beijing 100084,china 3 College of Applied Science,Harbin university of Science and Technology,Harbin 150080,china department of physics Tsinghua University Beijing 100084 China tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 China College of Applied Science Harbin University of Science and Technology Beijing 100084 China

The biggest obstacle for long distance quantum communication is the channel loss and the channel noise on photons. In this paper,a method to solve this problem was analyzed using inspection and power insertion (IPI). It is proved that quantum communication may be established over arbitrarily long distance using this technology. The amount of resources required is a polynomial function of the dis-tance. IPI is proposed as a general technique to prolong quantum secure direct communication where secret messages are transmitted directly over a quantum channel.

关键词：长距离量子通信量子安全通信量子密匙分布噪声

The Anti-Vibrating-Impact Research of the Piezoelectric Resonator Force Sensor

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稀有金属材料与工程 2006年第S3期 625-626页

作者： Junling Lu~1 Wenjie Tian~2 Lingling Liu~2 Fuxue Zhang~2 (1.department of physics,tsinghua university,beijing 100084,china) (2.Research Center of Sensor Technology,beijing Information Technology Institute,beijing 100101,china)

Based on the analysis of one-dimension inertial accelerometer movement model,from which the resolution of the accelerometer inertial mass displacement equation was derived,the response of the sensor sensing element to vibration and impact of various frequencies was *** theoretical and experimental results show that a reasonable configuration among the sensing element inherent frequency,environmental exciting frequency and the damp factors of the sensor is the key to prevent the sensor from *** sensor has good anti-vibrating impact ability when the relative damp factor is 0.7,and the environmental interferential vibrating frequency is less than 0.35 times of the inherent frequency of the sensing element.

关键词： piezoelectric resonator force sensor vibrating impact sensor-adapted ability

The Characteristics of the Shear-Vibrating Quartz Crystal Resonator

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稀有金属材料与工程 2006年第S3期 627-629页

作者： Wenjie Tian~1 Lingling Liu~1 Junling Lu~2 Fuxue Zhang~1 (1.Research Center of Sensor Technology,beijing Information Technology Institute,beijing 100101,china) (2.department of physics,tsinghua university,beijing 100084,china)

According to the piezoelectric equation and the vibration theory of the quartz crystal,the relations between the vibrating frequency and structural parameters under the thickness-shear-vibration of AT-cut quartz crystal have been studied. The frequency conditions under which quartz crystal resonator formed stationary wave inside the electrode district and the transmission characteristics of wave outside the electrode district have also been discussed.A quartz crystal resonator was developed based on this *** experiment showed that the force-sensing characteristics were independent of the fixation of the crystal *** detecting distinguish ability was up to 0.001°,and the short-term frequency stability was up to 1.38×10~ （-10）/min.

关键词： quartz crystal shear-vibration stationary wave characteristic quartz resonator

First-principles study of the effects of Si doping on geometric and electronic structure of closed carbon nanotube

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Science Bulletin 2005年第17期 9-14页

作者： ZHOU Junzhe1 & WANG Chongyu1, 2 1. department of physics, tsinghua university, beijing 100084, china 2. International Centre for Materials physics, Chinese Academy of Sci-ences, Shenyang 110016, china

The effects of Si doping on geometric and elec-tronic structure of closed carbon nanotube (CNT) are stud-ied by, a first-principles method, DMol. It is found that the local density of states at the Fermi level (EF) increases due to the Si-doping and the non-occupied states above the EF go down toward the lower energy range under an external elec-tronic field. In addition, due to the doping of Si, a sub-tip on the CNT cap is formed, which consisted of the Si atom and its neighbor C atoms. From these results it is concluded that Si-doping is beneficial to the CNT field emission properties.

关键词： carbon nanotube doping electronic structure field emission.

Electronic structure of edge dislocation of core-doped Ti in Fe

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Progress in Natural Science:Materials International 2004年第6期 15-20页

作者： DANG Hongli 1 *,WANG Chongyu 1,2,3 and SHU Xiaolin 1(1. Central Iron and Steel Research Institute,beijing 100081,china 2. department of physics,tsinghua university,beijing 100084,china 3. International Center for Materials physics,Academica,Shenyang 110016,china) Central Iron and Steel Research Institute，beijing 100081，china Central Iron and Steel Research Institute，beijing 100081，china department of physics，tsinghua university，beijing 100084 China International Center for Materials physics，Academica，Shenyang 110016，china

The electronic structure of an edge dislocation doped Ti lying in the (001) plane with Burgers Vector along [100] direction in body-centered cubic iron is investigated using the first principles discrete variational method (DVM) based on the density-functional theory. The binding energy,impurity formation energy,interatomic energy,Mulliken orbital populations and charge density difference are presented in this paper. By calculating the binding energy of the clean dislocation system and the Ti-doped system,it is found that the binding energy of Ti-doped dislocation system is lower than that of the clean dislocation system,which implies that the Ti-doped dislocation system is more stable than the clean dislocation system. The calculated result of the impurity formation energy predicts the trapping effect of dislocation core for Ti,which shows that Ti atom prefers to occupy the place at the dislocation core. The calculated results of the interatomic energy and the difference charge density of dislocation doped Ti system indicate that the stronger bonding formed between the Ti impurity and its neighbor Fe atoms will affect the mechanical property of edge dislocation. Considering the influence of Ti on the electronic structure and the energies,we can predict that the trace Ti in transition metal Fe with dislocation defect can give a significant contribution to the solid solution hardening effects and will influence the mechanical property of materials.

关键词： edge dislocation doping effect electronic structure.