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Constraints of f(R) gravity in Palatini approach with observational Hubble data

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Science china({1.,Mechanics & Astronomy) 2011年第8期54卷 1378-1383页

作者： zhai zhongxu & liu wenbiao department of physics, Institute of theoretical physics, beijing normal university, beijing 1.0875, china 1. department of {1. Institute of Theoretical Physics Beijing Normal University Beijing 100875 China

We use the newly released observational H(z) data (OHD), the Cosmic Microwave Background (CMB) shift parameter, and the Baryon Acoustic Oscillation (BAO) measurements data to constrain cosmological parameters of f(R) gravity in Palatini formalism in which the f(R) form is defined as f(R) = R β/Rn. Under the assumption of a spatially flat FRW universe, we get the best fitting results of the free parameters (Ωm0, n). In the calculation, we marginalize the likelihood function over H0 by integrating the probability density P ∝ e-χ2/2 to obtain the best fitting results and the confidence regions in the Ωm0-n plane. The constraints results of (Ωm0, n) = (0.33, 0.41. by OHD only and (Ωm0, n) = (0.23, 0.08) by the combination of OHD+CMB+BAO both indicate that the universe goes through three last phases, i.e., radiation dominated, matter-dominated, and late time accelerated expansion without introduction of dark energy.

关键词： f(R) gravity OHD CMB BAO accelerating expansion dark energy

The information entropy of a static dilaton black hole

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Science china({1.,Mechanics & Astronomy) 2008年第2期51卷 113-125页

作者： liu ChengZhou Institute of {1. physics, Binzhou university, Binzhou 256600, china department of physics, beijing normal university, beijing 1.0875, china 1. Institute of theoretical {1. Binzhou University Binzhou 256600 China 2. department of {1. Beijing Normal University Beijing 100875 China

In accordance with holographic principle, by calculating the statistical entropy of the quantum field just at the event horizon of the Garfinkle-Horowitz-Strominger dilaton black hole, the information entropy of the black hole was investigated and the Bekenstein-Hawking formula was obtained. The results show that black hole entropy is identical with the statistical entropy of the quantum field at the horizon. Using the generalized uncertainty relation, the divergence of the state density near the event horizon in usual quantum field theory was removed, and the cutoffs and the little mass approximation in the heat gas method of black hole entropy were avoided. Thus, the microstates of the massive scalar field just at the event horizon of the static dilaton black hole were studied directly and a description on holograph principle was presented. By using residue theorem, the integral difficulty in the calculation was overcome, and the information entropy and the Bekenstein-Hawking formula were obtained quantitatively. Compared with the black hole entropy from the loop quantum gravity, the consistency of methods and results of calculating black hole entropy in non-commutative quantum field theory and loop quantum gravity was investigated. By this, the gravity correction constant in the generalized uncertainty relation was suggested and the sense of holographic principle was discussed.

关键词： black hole entropy holographic principle non-commutative quantum field theory event horizon loop quantum gravity

Hawking radiation and thermodynamics of a Vaidya-Bonner black hole

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Research in Astronomy and Astrophysics 2010年第1期10卷 33-38页

作者： Zhen-Feng Niu wen-{1. liu department of {1. Hebei North University Zhangjiakou 075000 China department of {1. Institute of Theoretical Physics Beijing Normal University Beijing 100875 China

Using Parikh＇s tunneling method, the Hawking radiation on the apparent horizon of a Vaidya-Bonner black hole is calculated. When the back-reaction of particles is neglected, the thermal spectrum can be precisely obtained. Then, the black hole thermodynamics can be calculated successfully on the apparent horizon. When a relativistic perturbation is applied to the apparent horizon, a similar calculation can also lead to a purely thermal spectrum. The first law of thermodynamics can also be derived successfully at the new supersurface near the apparent horizon. When the event horizon is thought of as a deviation from the apparent horizon, the expressions of the characteristic position and temperature are consistent with the previous viewpoint which asserts that the thermodynamics should be based on the event horizon. It is concluded that the thermodynamics should be constructed exactly on the apparent horizon while the event horizon thermodynamics is just one of the perturbations near the apparent horizon.

关键词： black hole physics -- relativity -- kinematics and dynamics

Synthesis of superheavy nuclei with ^(238)U target

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Science china({1.,Mechanics & Astronomy) 2009年第10期52卷 1482-1488页

作者： liu ZuHua1,3 & BAO JingDong2,4 1 Key Laboratory of Beam Technology and Material Modification of Ministry of Education,beijing normal university,beijing 1.0875,china 2 department of physics,beijing normal university,beijing 1.0875,china 3 china Institute of Atomic Energy,beijing 102413,china 4 Center of theoretical Nuclear physics,National Laboratory of Heavy Ion Accelerator of Lanzhou,Lanzhou 730000,china Key Laboratory of Beam Technology and Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China department of {1. Beijing Normal University Beijing 100875 China china Institute of Atomic Energy Beijing 102413 China Center of theoretical Nuclear {1. National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

The production of superheavy nuclei with Z=1.8-1.6 via hot fusion reactions of the neutron-rich projectiles with 238U target is systematically *** results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z *** cross sections of the superheavy nuclei at Z = 1.2 and 1.5 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

关键词： superheavy nuclei fusion reaction cross section 238U target

Shape phase transitions in nuclei:Effective order parameters and trajectories

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Science china({1.,Mechanics & Astronomy) 2011年第S1期54卷 88-97页

作者： ZHANG Yu1,2, HOU ZhanFeng2 & liu YuXin2,3 1department of physics, Liaoning normal university, Dalian 116029, china 2department of physics and the State Key Laboratory of Nuclear physics and Technology, Peking university, beijing 100871, china 3Center of theoretical Nuclear physics, National Laboratory of Heavy Ion Accelerator, Lanzhou 720000, china 1. department of {1. Liaoning Normal University Dalian 116029 China2. Department of Physics and the State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China3. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 720000 China

We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first from the second-order phase transition in theory above a certain boson number N (about 50), but in experiments, only those quantities, such as E(L1.)/E(02+) and B(E2; (L+2)1.→ L1./B(E2; 21.→ 01., etc., of which the monotonous transitional behavior in the second-order phase transition is broken in the first order phase transition independent of N, are qualified as the effective order parameters. By implementing the originally proposed effective order parameters and the new ones, we find that the isotones with neutron number Nn = 62 are a trajectory of the second order phase transition. In addition, we predict that the transitional behavior of isomer shifts of Xe, Ba isotopes and Nn = 62 isotones is approximately monotonous due to the finiteness of nuclear system.

关键词： nuclear shape phase transition interacting boson model effective order parameter finite particle number effect transition trajectory

Estimating surface evapotranspiration using combined MODIS and CBERS-02 data

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Science china(Technological Sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2, liu Qinhuo1, TANG Yong1,3, TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2, ZHENG Hongsheng4 & CHEN Jiayi4 1. State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of Sciences, beijing 100101, china 2. Research Center for Remote Sensing and GIS, department of Geography, beijing normal university, beijing 1.0875, china 3. Graduate university of Chinese Academy of Sciences, beijing 100039, china 4. department of Atmospheric physics, Peking university, beijing 100871, china 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China2. Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China3. Graduate University of Chinese Academy of Sciences 100039 Beijing China4. Department of Atmospheric Physics Peking University 100871 Beijing China

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1.m resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02 data were used to produce land use class of Baiyangdian area, Hebei Province, china in the autumn of 2004. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the {1. analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

极化子效应对量子盘中线性和非线性光吸收系数的影响

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物理学报 2002年第9期51卷 2022-2028页

作者：刘翠红陈传誉马本堃北京师范大学物理系和理论物理研究所北京100875 广州大学理学院物理与电子信息系广州510405

利用密度矩阵的方法 ,得出了考虑极化子效应的量子盘的线性和非线性光吸收系数的解析表达式 ,并以GaAs为例讨论了光吸收系数与不同的入射光子能量和量子盘的厚度之间的关系 .结果表明。

关键词：量子盘极化子效应线性光吸收系数量子点非线性光吸收系数半导体非线性光学

Theory study of shapes in ^(1.7,1.9)Tl nuclei

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Science china({1.,Mechanics & Astronomy) 2009年第6期52卷 818-821页

作者： liu YanXin1. YU ShaoYing1.2,3, SHEN CaiWan1.5 & DONG YongSheng1.2,4 1.School of Science, Huzhou Teachers College, Huzhou 31.000,{1. 2 School of Science and Information Engineering, Zhejiang normal university, Jinhua 321.00,{1. 3 Institute of theoretical physics, Chinese Academy of Sciences, beijing 1.0080,{1. 4 department of physics, Jining Teachers College, Jining 01.000,{1. 5 Center of theoretical Nuclear physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000,{1. School of Science Huzhou Teachers College Huzhou 313000 China School of Science and Information Engineering Zhejiang Normal University Jinhua 321000 China Institute of theoretical {1. Chinese Academy of Sciences Beijing 100080 China department of {1. Jining Teachers College Jining 012000 China Center of theoretical Nuclear {1. National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

The nuclear shapes of 1.7,1.9Tl were investigated theoretically in this work. The total routhian surface (TRS) calculations were performed for N=1.6 and 1.8 isotopes of thal{1.m (Z=81.. The single-particle energies were obtained from the deformed Woods-Saxon potential, with the Lipkin-Nogami (LN) treatment of pairing. It is found that the collective oblate rotation coexists with the high-K prolate rotation. Superdeformed prolate rotation is included in this calculation.

关键词： nuclear shape oblate rotation prolate rotation

THz spectrum of reduced glutathione

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Science china({1.,Mechanics & Astronomy) 2005年第5期48卷 585-592页

作者： WANG Weining1. YAN Haitao1. YUE Weiwei1. ZHAO Guozhong1. ZHANG Cunlin1. {1. Haibo2 & ZHANG Xicheng2 1. department of physics, Capital normal university, beijing 1.0037, china 2. Center for Terahertz Research, Rensselaer Polytechnic Institute, Tory, NY, USA 1. department of {1. Capital Normal Univesity 100037 Beijing China 2. Center for Terahertz Research Rensselaer Polytechnic Institute Tory NY USA

The optical characteristics of reduced glutathione molecules between 0.2 THz and 2.4 THz have been investigated by THz time-domain spectroscopy (THz-TDS). The absorption characteristics and optical parameters of the reduced glutathione purged with Nitrogen at room temperature were obtained experimentally. The measured results were fitted well with the theoretical results computed by using Density Functional Theory (DFT) in far-infrared range. Also the conformation of the reduced glutathione molecule was simulated by Gaussian 03. This work has demonstrated significantly that THz-TDS spectroscopy can further be used to study other biological molecules in biological and biomedical engineering.

关键词： THz time domain spectroscopy, reduced glutathione, absorption spectrum, biological engineering.