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CHEMICAL STRUCTURE DEPENDENCE OF THE INTERNAL ENERGY CONTRIBUTION IN RUBBER ELASTICITY

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chinese Journal of Polymer science 2001年第5期19卷 447-449页

作者： Juan Sun Xiao-zhen Yang Polymer physics Laboratory center for Molecular sciences, Institute of Chemistry {3. beijing 100080 china 中科院化学所高分子物理及化学国家重点实验室北京

Conformational elasticity theory recently developed has been used to explore the internal energy contribution to the elastic force f(e)/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene). Calculated f(e)/f values are in good agreement with those obtained experimentally. Results show that behavior of f(e)/f is mainly contributed by chemical structure, or intramolecular interaction, supporting the experimental observations, and that the internal energy contribution is strain dependent.

关键词： conformational elasticity theory internal energy contribution poly(cis-1,4-isoprene) poly(trans-1,4-isoprene)

fMRI time series analysis based on stationary wavelet and spectrum analysis

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Progress in Natural science:Materials International 2006年第11期16卷 1171-1176页

作者： ZHI Lianhe~ 1,2,3., ZHAO Xia~4, SHAN Baoci~1**, PENG Silong~5, YAN Qiang~1, YUAN Xiuli~1 and TANG Xiaowei~ 1,6 (1. Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy physics, chinese academy of sciences, beijing 100049, {3. 2. Graduate School of chinese academy of sciences, beijing 100049, {3. 3. Department of physics, Zhoukou Normal University, Zhoukou 466100, {3. 4. Research Imaging center, University of Texas Health science center, San Antonio, Texas 78229, USA 5. National ASIC Design and Engineering center, Institute of Automation, chinese academy of sciences, beijing 100049, {3. 6. Department of physics, Zhejiang University, Hangzhou 3.0027, {3.) Key Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Graduate School of chinese academy of sciences Beijing 100049 China Department of physics Zhoukou Normal University Zhoukou 466100 China Research Imaging center University of Texas Health Science Center San Antonio TX 78229 United States National ASIC Design and Engineering center Institute of Automation Chinese Academy of Sciences Beijing 100049 China Department of physics Zhejiang University Hangzhou 310027 China

The low signal to noise ratio (SNR) of functional MRI (fMRI) prefers more sensitive data analysis methods. Based on stationary wavelet transform and spectrum analysis, a new method with high detective sensitivity was developed for analyzing fMRI time series, which does not require any prior assumption of the characteristics of noises. In the proposed method, every component of fMRI time series in the different time-frequency scales of stationary wavelet transform was discerned by the spectrum analysis, then the components from noises were removed using the stationary wavelet transform, finally the components of real brain activation were detected by cross-correlation analysis. The results obtained from both simulated and in vivo visual experiments illustrated that the proposed method has much higher sensitivity than the traditional cross-correlation method.

关键词： fMRI stationary wavelet transform spectrum analysis data analysis.

Two mode photon bunching effect as witness of quantum criticality in circuit QED

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science china(physics,Mechanics & Astronomy) 2009年第12期52卷 1898-1905页

作者： AI Qing1,WANG YingDan2,LONG GuiLu1,3.& SUN ChangPu4 1 Department of physics,Tsinghua University,beijing 100084,china 2 Department of physics,University of Basel,Klingelbergstrasse 82,4056 Basel,Switzerland 3.Tsinghua National Laboratory for Information science and Technology,beijing 100084,china 4 Institute of theoretical physics,chinese academy of sciences,beijing 100080,china Department of physics Tsinghua University Beijing China Department of physics University of Basel Basel Switzerland Tsinghua National Laboratory for Information science and Technology Beijing China Institute of theoretical physics Chinese Academy of Sciences Beijing China

We suggest a scheme to probe critical phenomena at a quantum phase transition (QPT) using the quantum correlation of two photonic modes simultaneously coupled to a critical system. As an experimentally accessible physical implementation,a circuit QED system is formed by a capacitively coupled Josephson junction qubit array interacting with one superconducting transmission line resonator (TLR). It realizes an Ising chain in the transverse field (ICTF) which interacts with the two magnetic modes propagating in the TLR. We demonstrate that in the vicinity of criticality the originally independent fields tend to display photon bunching effects due to their interaction with the ICTF. Thus,the occurrence of the QPT is reflected by the quantum characteristics of the photonic fields.

关键词： quantum phase transition photon bunching circuit QED

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,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 Department of physics Center for Optoelectronics Materials and Devices Zhejiang Sci-Tech University Hangzhou China National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China Department of physics Peking University Beijing 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

Prediction model for spring dust weather frequency in North china

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science china Earth sciences 2008年第5期51卷 709-720页

作者： LANG XianMei center for Disastrous Climate Research and Prediction, Institute of Atmospheric physics, chinese academy of sciences, {3. 100029, china center for Disastrous Climate Research and Prediction Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

It is of great social and scientific importance and also very difficult to make reliable prediction for dust weather frequency (DWF) in North china. In this paper, the correlation between spring DWF in beijing and Tianjin observation stations, taken as examples in North china, and seasonally averaged surface air temperature, precipitation, Arctic Oscillation, Antarctic Oscillation, South Oscillation, near surface meridional wind and Eurasian westerly index is respectively calculated so as to construct a prediction model for spring DWF in North china by using these climatic factors. Two prediction models, i.e. model-I and model-II, are then set up respectively based on observed climate data and the 3.-year (1970 -2001) extra-seasonal hindcast experiment data as reproduced by the nine-level Atmospheric General Circulation Model developed at the Institute of Atmospheric physics (IAP9L-AGCM). It is indicated that the correlation coefficient between the observed and predicted DWF reaches 0.93. in the model-I, suggesting a high prediction skill one season ahead. The corresponding value is high up to 0.948 for the subsequent model-II, which involves synchronous spring climate data reproduced by the IAP9L-AGCM relative to the model-I. The model-II can not only make more precise prediction but also can bring forward the lead time of real-time prediction from the model-I’s one season to half year. At last, the real-time predictability of the two models is evaluated. It follows that both the models display high prediction skill for both the interannual variation and linear trend of spring DWF in North china, and each is also featured by different advantages. As for the model-II, the prediction skill is much higher than that of original approach by use of the IAP9L-AGCM alone. Therefore, the prediction idea put forward here should be popularized in other regions in china where dust weather occurs frequently.

关键词： spring dust weather frequency prediction model iap9l-agcm hindcast experiment real-time prediction

VISCOELASTIC BEHAVIOR OF THE NON-HOOKE DEFORMATION BEFORE YIELDING IN UNIAXIAL DRAWING OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)

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chinese Journal of Polymer science 2001年第4期19卷 399-405页

作者： Zhen-hua Yuan De-yan Shen Ren-yuan Qian Polymer physics Laboratory center for Molecular science, Institute of Chemistry {3., beijing 100080 china 中科院化学所高分子物理及化学国家重点实验室北京

Viscoelastic behavior of the non-Hooke deformation of amorphous PET film before yield was investigated in the temperature region 74-80.5 degreesC around the glass transition temperature. The film specimen was drawn to yield point followed by unloading to zero stress, then the residual deformation was held constant; while the subsequent evolution of the stress was recorded. An induction period was found in the course of stress evolution followed by a stress step-increase. The induction period decreases with increasing drawing temperature with an activation energy of 1.10 MJ/mol.K, which is attributed to the time needed for the relaxation of rubbery deformation through cooperative internal rotations. At temperatures lower than 74 degreesC, there is no stress increase or the induction period becomes too long to be observed. Thus the nature of anelasticity in the non-Hooke region before yielding is attributed to stress induced rubbery deformation. The experimental results are interpreted in terms of Perez' theological model of a series connected Hooks spring and a Voigt element consisting of a parallel connected elastic spring and a dashpot.

关键词： pre-yield deformation PET uniaxial drawing non-Hooke deformation viscoelasticity stress induced rubbery deformation

Fluorescence dynamics of interactions between polyamide PyPyPyβDp and DNA

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science china Chemistry 2006年第1期49卷 75-80页

作者： ZHANG Huijuan1,2, WANG Jin3. WU Yishi1, YUAN Gu3. AI Xicheng1, WANG Li4 & ZHANG Jianping1 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, chinese academy of sciences, beijing 100080, china 2. School of Life {3. and Technology, beijing Institute of Technology, beijing 100081, china 3. College of Chemistry and Molecular Engineering, Peking University, beijing 100080, china 4. center for Condensed Matter physics, Institute of physics, chinese academy of sciences, beijing 100080, china Correspondence should be addressed to Ai Xicheng and Zhang Jianping State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing China School of Life science and Technology Beijing Institute of Technology Beijing China College of Chemistry and Molecular Engineering Peking University Beijing China center for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing China

The photophysical properties of the polyamide PyPyPyβDp (PPP) were investigated by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. It was found that the excited-state properties of PPP are very sensitive to solvents. In TKMC buffer PPP exhibited weak fluorescence with a decay time constant of 16 ps, while with the decrease of the solvent polarity PPP showed the blue-shifted peak position, increased inten-sity and lengthened life-time for its fluorescence behavior. In the presence of calf thymus DNA, it was observed that the fluorescence intensity was enhanced and the fluorescence lifetime increased from 16 to 3. ps for PPP, which verified that PPP bound into the minor groove of DNA duplex.

关键词： polyamide (PPP), calf thymus DNA (ctDNA), time-resolved fluorescence spectroscopy, recognition dynamics.

The red damping wing of Gunn-Peterson trough in the high redshift GRBs

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science china(physics,Mechanics & Astronomy) 2009年第9期52卷 1428-1433页

作者： XU Zhou1,2 & WEI DaMing1,3.1 Purple Mountain Observatory, chinese academy of sciences, Nanjing 210008, china 2 Graduate University of chinese academy of sciences, {3. 100012, china 3.Joint center for Particle Nuclear physics and Cosmology of Purple Mountain Observatory-Nanjing University, Nanjing 210008, china Purple Mountain Observatory Chinese Academy of Sciences Nanjing China Graduate University of chinese academy of sciences Beijing China Joint center for Particle Nuclear physics and Cosmology of Purple Mountain Observatory-Nanjing University Nanjing China

We calculate the red damping wing of Gunn-Peterson trough taking the evolution of the neutral fraction into consideration and take a clear look at the ionized region around the ionizing sources. We get the result that the damping wing flux feature is mainly determined by the neutral hydrogen outside the ionized bubble and the cut off in the damping wing would be useful to get the size of the ionized bubble. We also fit the red damping wing of the recently discovered high redshift GRB080913.and find that the ionized bubble is too small to create apparent cut off in the spectrum of this burst.

关键词： cosmology theory intergalactic medium gamma ray burst

Isospin-dependent relativistic microscopic optical potential in the Dirac Brueckner-Hartree-Fock method

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science china(physics,Mechanics & Astronomy) 2004年第2期47卷 189-198页

作者： RONG Jian1 & MA Zhongyu1,2,3.1. china Institute of Atomic Energy, beijing 102413. china 2. {3. of Nuclear theoretical physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lan-zhou 73.000, china 3. Institute of theoretical physics, chinese academy of sciences, beijing 100080, china Correspondence should be addressed to Rong Jian (email: jrong@***) china Institute of Atomic Energy Beijing China center of Nuclear theoretical physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China Institute of theoretical physics Chinese Academy of Sciences Beijing China

The relativistic microscopic optical potential in the asymmetric nuclear matter is studied in the framework of the Dirac Brueckner-Hartree-Fock method. A new decomposition of the Dirac structure of the nuclear self-energy in nuclear matter is adopted. The self-energy of a nucleon with E > 0 in nuclear matter is calculated with the G matrix in the Hartree-Fock approach. The optical potential of a nucleon in the nuclear medium is identified with the nucleon self-energy. The energy and asymmetric parameter dependence of the relativistic optical potentials for proton and neutron are discussed. The resulting Schroedinger equivalent potentials have reasonable behaviors of the energy dependence. The asymmetric parameter dependence of relativistic optical potentials and Schroedinger potentials are emphasized.

关键词： Dirac Brueckner Hartree-Fock, relativistic microscopic optical potential, asymmetric nuclear matter, isospin-dependence.