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Lookback time as a test for f(R) gravity in the Palatini approach

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Research in Astronomy and Astrophysics 2011年第11期11卷 1257-1265页

作者： Zhong-Xu Zhai and Wen-Biao Liu department of physics, Institute of Theoretical physics, beijing normal university, beijing 100875, China department of physics Institute of Theoretical Physics Beijing Normal University Beijing 100875 China

We use the recently released data of lookback time (LT)-redshift relation, the cosmic microwave background shift parameter and the baryon acoustic oscillation measurements to constrain cosmological parameters of f (R) gravity in the Palatini formalism by considering the f (R) form of type (a) f (R) = R β/Rn and (b) f (R) = R + α ln R β. Under the assumption of a Friedmann-Robertson-Walker universe, we achieved the best fitting results of the free parameters (Ωm0, n) for (a) and (Ωm0, α) for (b). We find that current LT data can provide interesting and effective constraints on gravity models. Compared with other data, the LT constraints favor a smaller value of the non-relativistic matter energy density.

关键词： cosmology cosmic microwave background

OPTIMIZATION OF ADAPTIVE DIRECT METHOD FOR APPROXIMATE SOLUTION OF INTEGRAL EQUATIONS OF SEVERAL VARIABLES

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Acta Mathematica Scientia 2004年第2期24卷 228-234页

作者：马万房艮孙 departmentofMathematics BeijingNormalUniversityBeijing100875China

This paper determines the exact error order on optimization of adaptive direct methods of approximate solution of the class of Fredholm integral equations of the second kind with kernel belonging to the anisotropic So... 详细信息

关键词： Integral equations direct methods anisotropic sobolev classes

SINGLE BIRTH PROCESSES

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Chinese Annals of Mathematics,Series B 1999年第1期20卷 77-82页

作者： CHEN MUFA(department of Mathematics,beijing{2. university,beijing 100875,China) department of Mathematics Beijing Normal University Beijing 100875 China

The single birth process is a Markov chain, either time-continuous or time-discrete, valuedin the non-negative integers: the system jumps with positive rate from k to k + 1 but not tok +j for all j 2.(this explains the meaning of 'single birth') . However, there is no restrictionfor the jumps from k to k - j(1 j< k). This note mainly deals with the uniqueness problemfor the time-continuous processes with an extension: the jumps from k to k + 1 may also beforbidden for at most finite number of k. In both cases (time-continuous or -discrete), thehitting probability and the first moment of the hitting time are also studied

关键词： Markov chains Single birth process Uniqueness criterion

The information entropy of a static dilaton black hole

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Science China(physics,Mechanics & Astronomy) 2008年第2期51卷 113-125页

作者： LIU ChengZhou Institute of Theoretical physics, Binzhou university, Binzhou 2.6600, China {2. of physics, beijing normal university, beijing 100875, China Institute of Theoretical physics Binzhou University Binzhou China department of physics Beijing Normal University Beijing 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

Self-talk of Reflection Hologram During its construction

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Chinese Journal of Lasers 1996年第4期B5卷 334-340页

作者： LIU Dahe ZHOU Jing(department of physics,{2.,beijing100875, China) beijing normal Univ Beijing China

Ｓｅｌｆ－ｔａｌｋｏｆＲｅｆｌｅｃｔｉｏｎＨｏｌｏｇｒａｍＤｕｒｉｎｇｉｔｓｃｏｎｓｔｒｕｃｔｉｏｎ￥ＬＩＵＤａｈｅ；ＺＨＯＵＪｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，ＢｅｉｊｉｎｇＮｏｒｍａｌＵｎｉｖｅｒｓ... 详细信息

Ｓｅｌｆ－ｔａｌｋｏｆＲｅｆｌｅｃｔｉｏｎＨｏｌｏｇｒａｍＤｕｒｉｎｇｉｔｓｃｏｎｓｔｒｕｃｔｉｏｎ￥ＬＩＵＤａｈｅ；ＺＨＯＵＪｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓ，ＢｅｉｊｉｎｇＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎｇ１００８７５...

关键词： reflection hologram hologram grating self-talk

Solvation effects on brain uptakes of isomers of ^(99m)Tc brain imaging agents

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Chinese Science Bulletin 2002年第21期47卷 1786-1791页

作者： JIA Hongmei, MA Xiaohui, WANG Cunxin & LIU Boli1. department of Chemistry, beijing normal university,{2., China 2. Center for Biomedical Engineering, beijing Polytechnic university, beijing 10002., China department of Chemistry Beijing Normal University Beijing 100875 China Center for Biomedical Engineering Beijing Polytechnic University Beijing 100022 China

Analysis of electrostatic hydration free energies of the isomers of the 99mTc-BAT and 99mTc-DADT complexes is carried out using the computer simulation technique. The results show that not only a correlation exists between the logarithm of the brain uptake and the electrostatic hydration free energy for the isomers of 99mTc-brain radiopharmaceu-ticals, but also a linear relationship exists between the logarithm of the ratio of the brain uptake of the syn isomer to that of the anti one and the difference between the electrostatic hydration free energy of the syn-isomer and that of the anti one. Furthermore, the investigation on the important factors influencing the brain uptakes of 99mTc-radiophar-maceuticals and the reasons of the different biodistribution of the isomers of the 99mTc-complexes is explored at the molecular level. The results may provide a reference for the rational drug design of brain imaging agents.

关键词： 99mTc-brain imaging agent isomer brain uptake electro-static hydration free energy.

Recovery of functions via their irregular sampling values

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Chinese Science Bulletin 1998年第4期43卷 268-271页

作者： FANG Gensun department of Mathematics, beijing normal university,{2., China department of Mathematics Lkijing Normal University Beijing China

It is proved that if a function can be completely reconstructed by tempered splines which satisfy the real Kiesz basis condition as the degree of spline goes to infinity, then the function is band limited.

关键词： band limited function cardinal splines irregular sampling.

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Saturated models

Chinese Science Bulletin 1998年第7期43卷 562-564页

作者： CHEN Guolong department of Mathematics, beijing normal university,{2., China department of Mathematics Beijing Normal University Beijing China

An equivalent description of saturated models is given, and some properties of countable saturated models, almost saturated models and full models are discussed. New proofs of two important theorems of the related doc... 详细信息

关键词： almost saturated model full model power type.

Electroluminescent properties of three ternary europium complexes with different phenanthroline derivatives

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Science China Chemistry 2004年第4期47卷 326-334页

作者： BIAN Zuqiang1,2. GAO Deqing1, GUAN Min1, XIN Hao1, LI Fuyou1, HUANG Chunhui1, WANG Kezhi2.& JIN Linpei2.1. State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking university, beijing 100871, China 2.{2. of Chemistry, beijing normal university, beijing 100875, China State Key Laboratory of Rare Earth Materials Chemistry and Applications Peking University Beijing China department of Chemistry Beijing Normal University Beijing China

Three ternary Eu(III) complexes with general formula of Eu(DBM)3LN (DBM = dibenzoylmethanate, and LN (N = 1-3 ) stand for three different 1,10-phenanthroline derivatives) have been synthesized for vacuum deposition films-based electroluminescent devices. The complex Eu(DBM)3L3 (L3 = 2.phenyl-3-[3-(carbazol-9-yl)propyl]imidazo[4,5-f]1,10-phenan-throline) was designed with an effort to combine the electron-transporting phenanthroline platform and the hole-transporting carbazole group into one molecule expecting to improve both electron and hole transporting properties simultaneously. The results show that the variation of the neutral ligands in Eu(III) mixed ligand complexes is a simple and effective approach to the improvement in the thermal stability, PL and EL properties of materials. A double-layer device with the configuration of ITO/TPD (50 nm)/Eu(DBM)3L3 (50 nm)/Mg0.9Ag0.1 (2.0 nm)/Ag (100 nm) exhibited Eu(III)-based pure red emission with a maximum brightness of 561 cd/m2.at 16 V, and an onset driving voltage of 8 V. A device with the configuration of ITO/TPD (50 nm)/[Eu(DBM)3L3 (5 nm):BCP (5 nm)]4/BCP (2. nm)/AIQ (10 nm) Mg0.9Ag0.9 (110 nm)/Ag (100 nm) gave high efficient and pure red light emission with a luminance of 1419 cd/m2. Keywords dibenzoylmethane - electroluminescence - lanthanide - N ligands

关键词： dibenzoylmethane electroluminescence lanthanide N ligands