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Latest cosmological constraints on Cardassian expansion models including the updated gamma-ray bursts

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Research in Astronomy and Astrophysics 2011年第9期11卷 1019-1030页

作者： Nan Liang Pu-Xun Wu Zong-Hong Zhu department of Astronomy Beijing Normal University Beijing 100875 China Center for High Energy physics Peking University Beijing 100871 China Center of Nonlinear Science and department of physics Ningbo University Ningbo 315211 China

We constrain the Cardassian expansion models from the latest observa- tions, including the updated Gamma-ray bursts （GRBs）, which are calibrated using a cosmology independent method from the Union2 compilation of type Ia supernovae （SNe Ia）. By combining the GRB data with the joint observations from the Union2 SNe Ia set, along with the results from the Cosmic Microwave Background radia- tion observation from the seven-year Wilkinson Microwave Anisotropy Probe and the baryonic acoustic oscillation observation galaxy sample from the spectroscopic Sloan Digital Sky Survey Data Release. we find significant constraints on the model oarameters of the original Cardassian model ΩM0=0.282-0.014^0.015,n=0.03.0.05^＋0.05 and n=-0.16-3.26^＋0.25,β=0.76-0.58^＋0.3. of the modified polytropic Cardassian model, which are consistent with the ACDM model in a l-or confidence region. From the reconstruction of the deceleration parameter q（z） in Cardassian models, we obtain the transition redshift ZT = 0.73.± 0.04 for the original Cardassian model and ZT = 0.68 ± 0.04 for the modified polytropic Cardassian model.

关键词： gamma-rays bursts -- cosmology cosmological parameters

Preparation and Biological Distribution of New BATOs

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Chinese Chemical Letters 1997年第1期8卷 81-82页

作者： Jing Tao WANG Xiang Yun WANG Yuan Fang LIU(department of technical physics-{3., beijing 100871)(The current address is: Institute of Photographic Chemistry, Academia Sinica, Bejing 100101) beijing UNIV DEPT TECH PHYSBEIJING 100871PEOPLES R CHINA

Seven new boronic acid adducts of technetium(III) tris(dioxime) (BATO) were prepared and the biodistribution in mice of Tc-99m labelled BATOs were determined. The uptake of 1.62%1D in mice heart at 2 min after injection of (TcCl)-Tc-99m(MeCDO)(3.BMe indicates high myocardial extraction of this BATO. (TcCl)-Tc-99m(MeCDO)(3.BMe shows promise as a myocardial perfusion imaging agent.

关键词： DMG Preparation and Biological Distribution of New BATOs

The size effect on transport properties of colossal magnetoresistance materials La_(0.67)Ca_(0.3.)MnO_3

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Science china(physics,Mechanics & Astronomy) 2008年第3期51卷 251-257页

作者： LI PeiGang1,2,LEI Ming1,2,GUO YanFeng2,GUO Xi2,CHEN LeiMing2, TANG WeiHua1,2,SONG PengYun3.& CHEN JinPing3.1 department of physics,Center for Optoelectronics Materials and Devices,Zhejiang Sci-Tech university,Hangzhou 3.0018,{3. 2 National Laboratory for Condensed Matter physics,Institute of physics,Chinese Academy of Sciences,beijing 100080,{3. 3.department of physics,peking university,beijing 100875,{3. 1. department of physics Center for Optoelectronics Materials and Devices Zhejiang Sci-Tech University Hangzhou 310018 China 2. National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 3. department of physics Peking University Beijing 100875 China

High quality La0.67Ca0.3.MnO3.(LCMO) film was deposited via a novel pulsed electron deposition technique on SrTiO3.100) single crystal substrate. The micro-bridge with different widths was fabricated by using electron beam lithography (EBL) technique and their transport properties were studied. For the micro-bridges with width of 2 and 1.5 μm,the insulator-to-metal transition temperature (TP) keeps un-changed compared with the film. For the micro-bridges with width of 1 μm,the TP shifts towards the lower temperature by 50 K. When the width decreases down to 500 nm,the insulator-to-metal transition disappears. The magnetoresistance be-havior of these micro-bridges was studied,and the results show that the low field magnetoresistance (LFMR) decreases and the high field magnetoresistances (HFMR) keep almost unchanged as the width of micro-bridge is reduced.

关键词： colossal magnetoresistance pulsed electron deposition electron beam lithography electrical transport properties

Chemical characteristics of cloudwater over Maoer Mountain district

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Journal of Environmental Sciences 1993年第3期5卷 310-322页

作者： Yao Rongkui, Bai Yuhua, Chen Shufen, Shao Min, Tang XiaoyanEnvironmental Chemistry Division, department of technical physics,{3., beijing 100871, china

Samples of cloudwater, rainwater and ambient aerosol were collected over Maoer Mountain in the northeast of Guangxi Province in March 1988. The pH value of cloudwater ranged from 3.3. to 6.20 with a mean value of 4.3.. SO42- , NO3. , NH4+, Ca2+ and H+ were the principal ionic species of cloudwater. The advance of cold fronts into Maoer Mountain appeared to lead to higher major ionic concentration and acidity than that of warm fronts. The relative acidity and concentration of NO3. of cloudwater were much greater than that of aerosol samples. With the exception of. NO3. and H+, most of the concentration of SO42- and NH4+ in cloudwater came from the nucleation scavenging of aerosol. Gaseous nitric acid and organic acid from local may be one of the important source of cloudwater acidity. Compared with other sites, Maoer Mountain can be as a clean contrast station for studying acidic precipitation in Guangdong and Guangxi provinces.

关键词： acid precipitation cloudwater rainwater aerosol clean site.

Debating about the climate warming

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Progress in Natural Science:Materials International 2006年第1期16卷 1-6页

作者： WANG Shaowu1, LUO Yong2, ZHAO Zongci2, DONG Wenje2 and YANG Bao3.(1.department of Atmospheric Sciences, School of physics, peking university,{3., china 2. Laboratory for Climate Studies, china Meteorological Administration, beijing 100081, china 3. Institute of Cold and Arid Regions Environmental and Engineering, Chinese Academy of Sciences, Lanzhou 73.000, china) [a] department of Atmospheric Sciences School of Physics Peking University Beijing China [b] Laboratory for Climate Studies China Meterological Administration Beijing China [c] Institute of Cold and Arid Regions Environmental and Engineering Chinese Academy of Sciences Lanzhou China

Debating about the climate warming is reviewed. Discussions have focused on the validity of the temperature reconstruction for the last millennium made by Mann et al. Arguments against and for the reconstruction are introduced. Temperature reconstructions by other authors are examined, including the one carried out by Wang et al. in 1996. It is concluded that: (1) Ability of reproducing temperature variability of time scale less than 10 a is limited, so no sufficient evidence proves that the 1990s was the warmest decade, and 1998 was the warmest year over the last millennium. (2) All of the temperature reconstructions by different authors demonstrate the occurrence of the MWP (Medieval Warm Period) and LIA (Little Ice Age) in low frequency band of temperature variations, though the peak in the MWP and trough in LIA varies from one reconstruction to the others. Therefore, terms of MWP and LIA can be used in studies of climate change. (3. The warming from 1975 to 2000 was significant, but we do not know if it was the strongest for the last millennium, which needs to be proved by more evidence.

关键词： climate warming MWP LIA the 20th century.

How Fast Could a Proto-pulsar Rotate?

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Chinese Journal of Astronomy and Astrophysics 2002年第6期2卷 533-538页

作者： Ren-Xin Xu, Hong-Guang Wang and Guo-Jun Qiaodepartment of Astronomy, School of physics, peking university,{3. department of Astronomy School of Physics Peking University Beijing 100871

According to two estimated relations between the initial period and the dynamo-generated magnetic dipole field of pulsars, we calculate the statistical distributions of pulsar initial periods. It is found that proto-pulsars are very likely to have rotation periods between 20 ms and 3. ms, and that most of the pulsars rotate initially at a period < 60 ms. Our result supports the asymmetric neutrino emission model for pulsar kick.

关键词： pulsars neutron stars magnetic fields

On Hoava-Lifshitz cosmology

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Chinese physics C 2011年第5期35卷 429-435页

作者： CHEN Bin1) department of physics, and State Key Laboratory of Nuclear physics and Technology,{3., beijing 100871, china department of physics and State Key Laboratory of Nuclear Physics and Technology Peking University

We give a brief overview of the Horava-Lifshitz-gravity theory, its modifications and its implications in cosmology. In particular, we discuss the various issues on the gravitational scalar mode, including its decoupling, its role as inflaton and its stability. Our analysis shows that the scalar mode could decouple naturally at λ = 1 due to the extra gauge symmetry. On the other hand, the fact that the scalar mode becomes ghost when 1/3.〈 λ 〈 1 is a real challenge to the theory. We try to overcome this problem by modifying the action such that the RG flow lies outside the problematic region. We discuss the cosmological implications of the theory.

关键词： Horava-Lifshitz-gravity cosmology ghost

THE SEPARATION OF BASE METALS FROM PLATINUM METALS BY ION EXCHANGE

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Chinese Journal of Reactive Polymers 1992年第1期1卷 54-60页

作者： JIANG Lingen, and HUANG Yan department of technical physics,{3., beijing 100871, china

In this paper the separation of base metals Fe,Co,Ni and Cu from the platinum metals on a cation exchanger column was *** convenient separation conditions are 0.5mol·dm^-3.NaCl,pH=2. The recovery efficiency of Rh is ... 详细信息

关键词：碱金属分离铁铑钴阳离子交换树脂铜铂系金属镍

Convergence for Imaginary Time Step evolution in the Fermi and Dirac seas

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 327-330页

作者： LI FangQiong1,ZHANG Ying2 & MENG Jie2,3.4 1Guizhou university for Nationalities,Guiyang 550025,china 2State Key Lab Nucl. Phys. & Tech.,School of physics,{3. university,beijing 100871,china 3.chool of physics and Nuclear Energy Engineering,Beihang university,beijing 100191,china 4department of physics,university of Stellenbosch,Stellenbosch,South Africa 1. Guizhou university for Nationalities Guiyang 550025 China2. State Key Lab Nucl. Phys. & Tech. School of Physics Peking University Beijing 100871 China3. School of Physics and Nuclear Energy Engineering Beihang University Beijing 100191 China4. Department of Physics University of Stellenbosch Stellenbosch South Africa

The convergence for the Imaginary Time Step (ITS) evolution with time step is investigated by performing the ITS evolution for the Schrdinger-like equation and the charge-conjugate Schrdinger-like equation deduced from Dirac equation for the single proton levels of 12C in both the Fermi and Dirac seas. For the guaranteed convergence of the ITS evolution to the "exact" results,the time step should be smaller than a "critical" time step Δtc for a given single-particle level. The "critical" time step Δtc is more sensitive to the quantum numbers |κ| than to the energy of the single-particle level. For the single-particle levels with the same κ,their "critical" time steps are in the same order. For the single-particle levels with similar energy,a relatively small (large) "critical" time step for larger (smaller) |κ| is needed. These conclusions can be used in the future self-consistent calculation to optimize the evolution procedure.

关键词： Dirac equation Schrdinger-like equation Imaginary Time Step method convergence