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D^0 -~0 mixing and CP violation at BES-Ⅲ

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Chinese Physics C 2008年第6期32卷 470-476页

作者：李海波 Institute of High Energy Physics CAS

Recently, both BaBar and Belle experiments found evidences of neutral D mixing. In this paper, we discuss the sensitivities of the measurements of D mixing parameters at BES-Ⅲ. With CP tag technique at ψ（3770） peak, the extraction of the strong phase difference in D^0 → Kπ decay at BES-Ⅲ are discussed. We also make an estimate on the measurements of the mixing rate RM by using the coherent data at ψ（3770） peak. The CP violation in D system is predicted with an unobserved level in the Standard Model. Any significant CP violation in the D system indicates the existence of new physics. The sensitivity of the measurements of CP violation in the D system is estimated in the coherent D decays. Finally, the search for the rare D decays are discussed, in which some of the forbidden decays are smoking gun of new physics.

关键词： D mixing BES-Ⅲ experiment CP violation rare decay

Relief degree of land surface and its influence on population distribution in China

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Journal of Geographical Sciences 2008年第2期18卷 237-246页

作者： FENG Zhiming TANG Yan YANG Yanzhao ZHANG Dan Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The relief degree of land surface （RDLS） is an important factor for describing the landform at macro-scales. This study defines a concept for RDLS and applies the concept for population distribution study of the entire country. Based on the concept and macro-scale digital elevation model datum and ARC/INFO software, the RDLS at a 10 km×10 km grid size of China is extracted. This paper depicts systemically the spatial distributions of RDLS through analyzing the ratio structure and altitudinal characters of RDLS in China. The conclusions are drawn as follows： the RDLS in more than 63% of the area is less than one （1）（relative altitude is less than 500 m）, reflecting the fact that most of RDLS in China is low. In general, the RDLS in the west is larger than that in the east and so is the south than that of the north in China. The RDLS decreases with the increase of longitude and latitude and the change of RDLS at the latitudes of 28°N, 35°N, 42°N, as well as at the longitudes of 85°E, 102°E, 115°E could reflect the three major ladders of China. In the vertical direction, the RDLS increases with the increase of altitude. Analysis of the correlation between RDLS and population distribution in China and its regional difference shows that the R2 value between RDLS and population density is 0.91 and RDLS is an important factor influencing the spatial distribution of population. More than 85% of the people in China live in areas where the RDLS is less than one （1）, while the population in areas with RDLS greater than 3 accounts only for 0.57% of the total. The regional difference of correlation between RDLS and population within China is significant and such correlation is significant in Central China and South China and weak in Inner Mongolia and Tibet.

关键词： relief degree of land surface (RDLS) population distribution GIS China

Prediction of permafrost distribution on the Qinghai-Tibet Plateau in the next 50 and 100 years

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Science China Earth Sciences 2005年第6期48卷 797-804页

作者： NAN Zhuotong LI Shuxun CHENG Guodong State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Intergovernmental Panel on Climate Change (IPCC) in 2001 reported that the Earth air temperature would rise by 1.4-5.8℃ and 2.5℃ on average by the year 2100. China re-gional climate model results also showed that the air temperature on the Qinghai-Tibet Plateau (QTP) would increase by 2.2-2.6℃ in the next 50 years. A numerical permafrost model was developed to predict the changes of permafrost distribution on the QTP over the next 50 and 100 years under the two climatic warming scenarios, i.e. 0.02℃/a, the lower value of IPCC’s estima-tion, and 0.052℃/a, the higher value predicted by Qin et al. Simulation results show that ( i ) in the case of 0.02℃/a air-temperature rise, permafrost area on the QTP will shrink about 8.8% in the next 50 years, and high temperature permafrost with mean annual ground temperature (MAGT) higher than ?0.11℃ may turn into seasonal frozen soils. In the next 100 years, perma-frost with MAGT higher than ?0.5℃ will disappear and the permafrost area will shrink up to 13.4%. (ii) In the case of 0.052℃/a air-temperature rise, permafrost area on the QTP will reduce about 13.5% after 50 years. More remarkable degradation will take place after 100 years, and permafrost area will reduce about 46%. Permafrost with MAGT higher than ?2℃ will turn into seasonal frozen soils and even unfrozen soils.

关键词： permafrost distribution, scenario prediction, the Qinghai-Tibet Plateau (QTP), numerical methods, Geo-graphical Information System (GIS).

A study of time over threshold (TOT) technique for plastic scintillator counter

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Chinese Physics C 2008年第3期32卷 186-190页

作者：吴金杰衡月昆孙志嘉吴冲赵玉达杨桂安姜春华 Institute of High Energy Physics CASBeijing 100049China Graduate University of Chinese Academy of SciencesBeijing 100049China Institute of High Energy Physics CASBeijing 100049China Department of Physics Nanjing UniversityNanjing 210093China

A new charge measurement method, time over threshold （TOT）, has been used in some gas detectors lately. HereTOT is studied for TOF system, made of plastic scintillator counter, which can simplify the electronics of the system. The signal characteristics are measured and analyzed with a high quality oscilloscope, including noise, pedestal, signal amplitude, total charge, rise time and the correlation between them. The TOT and charge are related and can be fitted by some empirical formula. The charge measurement resolution by TOT is given and this will help the design of TOF electronics.

关键词： scintillator counter time over threshold (TOT) charge measurement relative resolution

Ultralong room temperature phosphorescence via the charge transfer-separation-recombination mechanism based on organic small molecule doping strategy

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Chinese Chemical Letters 2023年第7期34卷 205-209页

作者： Yanan Wang Chao Wang Jingran Zhang Yurong Guo Peng Zhao Xiaoxue Fang Guangjiu Zhao MolecularDynamic Chemistry Center Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of ScienceTianjin UniversityTianjin 300354China

Ultra-long room temperature phosphorescence(URTP) has been increasingly recognized in pure organic luminophor in recent years. Through a simpler molecular design and charge separation-recombination pathway, organic luminophor can achieve even better URTP properties. In this work, we achieved URTP in a system of host-guest doped benzophenone derivatives whose phosphorescence is visible to the naked eye. The differences in the wavelength lifetimes of luminescent emission correspond to different photophysical mechanisms. Through a combination of theoretical calculations and experiments, the host acts as a powerful substrate that restricts the motion of the guest and inhibits the non-radiative transitions of the guest, accompanied by a charge transfer separation-recombination process between the host and the guest, resulting in an URTP phenomenon. Transient absorption results demonstrate the existence of a charge-separated state. The design strategy via charge separation is generic and easy to implement,providing a direction for the future design of doped URTP.

关键词： Ultralong room-temperature phosphorescence Charge transfer-separation-recombination Organic small-molecule Doped system Luminescent mechanism

Online data quality monitoring system at BESⅢ

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Chinese Physics C 2012年第7期36卷 622-627页

作者：孙晓东胡继峰赵海升季晓斌王贻芳郑阳恒刘北江 Institute of High Energy Physics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

The online Data Quality Monitoring （DQM） tool plays an important role in the data recording process of HEP experiments. The BESIII DQM collects data from the online data flow, reconstructs them with offline reconstruction software and automatically analyzes the reconstructed data with user-defined algorithms. The DQM software is a scalable distributed system. The monitored results are gathered and displayed in various formats, which provides the shifter with current run information that can be used to identify problems quickly. This paper gives an overview of the DQM system at BESⅢ.

关键词： BESⅢ DQM sampling histogram

Coincidence Doppler Broadening Study of Elemental Metals

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Chinese Journal of Chemical Physics 2006年第3期19卷 203-206页

作者： Chuan-ying Xi Bang-jiao Ye Wei Kong Hui-min Weng Xian-yi Zhou Rong-dian Han Department of Modern Physics University of Science and Technology of China Hefei 230026 China

二十件纯元素的金属样品与拓宽系统(CDB ) 的巧合 Doppler 被学习了。结果显示出在 CDB 系列和这些样品的电子结构之间的关系。试验性的结果与简单理论预言相比，它证明拓宽 Doppler 系列的高动量的部分能被用来区分不同元素。

关键词：正电子湮灭符合多谱勒展宽金属元素鉴别

INFINITELY MANY SOLUTIONS FOR AN ELLIPTIC PROBLEM INVOLVING CRITICAL NONLINEARITY

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Acta Mathematica Scientia 2010年第6期30卷 2017-2032页

作者：曹道民严树森 Institute of Applied Mathematics AMSS Chinese Academy of Sciences Department of Mathematics The University of New England

We study the following elliptic problem：{-div（a（x）Du）=Q（x）｜u｜2-2u＋λu x∈Ω,u=0 onδΩ Under certain assumptions on a and Q, we obtain existence of infinitely many solutions by variational method.

关键词： semilinear elliptic equations infinitely many solutions variational method

Simulation of turbulent magnetic reconnection in the smallscale solar wind

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Science China Mathematics 2000年第6期43卷 629-637页

作者：魏奉思胡强 R.Schwen 冯学尚 Laboratory of Numerical Study for Heliospheric Physics Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China Max-Planck-Institut fuer Aeronomie D-37189 Katlenburg-LindauGermany

Some observational examples for the possible occurrence of the turbulent magnetic reconnection in the solar wind are found by analysing Helios spacecraft’s high resolution data. The phenom-ena of turbulent magnetic reconnections in small scale solar wind are simulated by introducing a third order accuracy upwind compact difference scheme to the compressible two-dimensional MHD flow. Numerical results verify that the turbulent magnetic reconnection process could occur in small scale in-terplanetary solar wind, which is a basic feature characterizing the magnetic reconnection in high-mag-netie Peynolds number ( RM = 2 000-10 000) solar wind. The configurations of the magnetic reconnection could evolve from a single X-line to a multiple X-line reconnection, exhibiting a complex picture of the formation, merging and evolution of magnetic islands, and finally the magnetic reconnection would evolve into a low-energy state. Its life-span of evolution is about one hour order of magnitude. Various magnetic and

关键词： solar wind magnetic reconnection turbulence.