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Evolution of desertification in a two-dimensional energy balance model coupled with thermodynamics and dynamics

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Science china Earth sciences 2010年第11期53卷 1726-1733页

作者： CHAO JiPing1,2 & LI YaoKun3,4 1national Marine Environmental Forecasting Center, beijing 100081, china 2First institute of Oceanography, State Oceanic Administration, Qingdao 266061, china 3State Key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china 4Graduate University of chinese academy of sciences, beijing 100049, china national Marine Environmental Forecasting Center Beijing China First institute of Oceanography State Oceanic Administration Qingdao China State Key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

The relationship between desert evolution and change in albedo has been investigated quasi-analytically using a zonal mean two-dimensional energy balance model which considers the radiation transmission process due to thermodynamics and bound- ary layer movement caused by kinetics. A climate state including temperature, zonal wind, meridional wind and vertical wind can be simulated according to the current zonal distribution of albedo. Given desert distribution, characterized by the value and distribution of albedo, the response of climate on albedo has been studied to analyze the evolution of desert climate. One significant result is that the simple model can reproduce mean meridional circulation. Another result indicates that climate corresponds to two equilibria. This happens when the junction temperature between vegetation and desert is higher than a certain critical value. As for the first equilibrium, the desert belt is predicted to move southward in the northern hemisphere with the increasing values of albedo, which corresponds to the current trend of climate change. For the second equilibrium, vegetation will expand northward with increasing values of albedo, which would indicate a narrowing of the desert belt. In order to determine if the two equilibria exist, new physical models are needed.

关键词： two-dimensional energy balance model desertification two equilibria

Growth of Pb S nanoclusters on specific sites of programmed oligodeoxynucleotides

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chinese physics B 2015年第1期24卷 398-403页

作者：陆颖滕翠娟李颖王惠徐春华胡书新李明 beijing national laboratory for condensed matter physics and Key laboratory of Soft matter physics Institute of PhysicsChinese Academy of Sciences

We develope a method to synthesize Pb S nanoclusters（NCs） using guanine-containing oligodeoxynucleotides（ODNs）as templates. The NCs on the ODNs are ultra small（ranging from ～ 0.5 nm to 2.1 nm） and luminescent in the visible region. They are characterized by photoluminescence（PL） spectra, transmission electron microscopy（TEM）, and X-ray powder diffraction（XRD）. The ODN–NC complexes can be used as customer-designed fluorophores which do not have the problem of multiple conjugations. The same method enables us to fabricate Pb S quantum dot molecules and connect them into nanowires, expanding their potential applications in molecule electronics and quantum computing.

关键词： Pb S nanoclusters quantum dot molecules oligodeoxynucleotides photoluminescence

Response synchronization: New progress in brain-visual information processing

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chinese Science Bulletin 1999年第16期44卷 1447-1458页

作者： ZHAO Songnian, XIONG Xiaoyun, YAO Guozheng and GUO Aike1. State Key laboratory of Atmospheric Boundary Layer physics and Atmospheric Chemistry , institute of Atmospheric physics , chinese academy of sciences , beijing 100029, china 2. Commission of the national Natural Science Foundation of china , beijing 100083, china 3. The Center of Information Science , Peking University, beijing 100871, china 4. Open laboratory of Visual Information Processing , institute of Biophysics , chinese academy of sciences , beijing 100101, china State Key laboratory of Atmospheric Boundary Layer physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Commission of the national Natural Science Foundation of china Beijing China The Center of Information Science Peking University Beijing China Open laboratory of Visual Information Processing Institute of Biophysics Chinese Academy of Sciences Beijing China

Studies on brain-vision have entered a new stage, after the stimulus-induced y synchronized oscillation of neuron group activities have been discovered in cat primary visual cortex. Naturally, how to understand the visual system became a very important methodological problem. From aspects such as information processing, nonlinear dynamics and neuronal network, some primary problems in vision studies have been deeply discussed, which are

关键词： neuron group (neural population) synchro-oscillation computational theory of vision response synchroniza-tion.

Study of the effect of atorvastatin on the interaction between ICAM-1 and CD11b by live-cell single-molecule force spectroscopy

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Science china Chemistry 2010年第4期53卷 752-758页

作者： LI Yi1, SHI XiaoLi2, LIU HuiLiang1, YI ShaoQiong3, ZHANG XueJie2 & FANG XiaoHong2 1Department of Cardiology, the General Hospital of chinese People’s Armed Police Forces, beijing 100039, china 2beijing national laboratory for Molecular sciences institute of Chemistry, chinese academy of sciences, beijing 100190, china 3State Key laboratory of Pathogen and Biosecurity beijing institute of Microbiology and Epidemiology, beijing 100071, china Department of Cardiology the General Hospital of Chinese People’s Armed Police Forces Beijing China beijing national laboratory for Molecular sciences Chinese Academy of Sciences Beijing China institute of Chemistry Chinese Academy of Sciences Beijing China State Key laboratory of Pathogen and Biosecurity Beijing China beijing institute of Microbiology and Epidemiology Beijing China

The interaction between the cell adhesion molecule CD11b and its ligand ICAM-1 plays an important role in inflammatory responses in the disease of atherosclerosis. Atorvastatin is a commonly prescribed statin drug which has been considered as one of the most potent therapeutic agents for atherosclerosis due to its lipid-lowering effect. Recently, there is a growing body of evidence that atorvastatin has anti-inflammatory effect. We have applied the advanced method of live-cell single-molecule force spectroscopy to investigate the effect of atorvastatin on adhesion force between ICAM-1 and CD11b. Our result showed that single-molecule binding force of ICAM-1 and CD11b detected by AFM in the living cells was about 40 pN, and atorvastatin did not affect this force by blocking ICAM-1 or CD11b. This was different from the ICAM-1 monoclonal antibody, which could directly reduce the binding force of ICAM-1 and CD11b. Flow cytometry results revealed that atorvastatin pretreatment decreased the ICAM-1 expression in TNF-α activated HUVECs, which may contribute to its anti-inflammatory effect. The study provides a new approach to study anti-inflammatory mechanism for clinic drugs.

关键词： atherosclerosis atorvastatin atomic force microscopy single-molecule force spectroscopy protein-protein interaction

A novel function for the cellulose binding module of cellobiohydrolase I

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Science china(Life sciences) 2008年第7期51卷 620-629页

作者： WANG LuShan 1,2 ,ZHANG YuZhong 1 &GAO PeiJi 1 1State Key laboratory of Microbial Technology,Shandong University,Jinan 250100,china 2beijing laboratory of Nanoscale physics&Devices,chinese academy of sciences,beijing 100080,china State Key laboratory of Microbial Technology Shandong University Jinan China beijing laboratory of Nanoscale physics & Devices Chinese Academy of Sciences Beijing China

A homogeneous cellulose-binding module(CBM)of cellobiohydrolase I(CBHI)from Trichoderma pseudokoningii S-38 was obtained by the limited proteolysis with papain and a series of chromatographs *** of FT-IR spectra demonstrated that the structural changes result from a weakening and splitting of the hydrogen bond network in cellulose by the action of CBMCBHI at 40℃for 24 *** results of molecular dynamic simulations are consistent with the experimental conclusions, and provide a nanoscopic view of the mechanism that strong and medium H-bonds decreased dramatically when CBM was bound to the cellulose *** function of CBMCBHI is not only limited to locating intact CBHI in close proximity with cellulose fibrils,but also is involved in the structural disruption at the fibre *** present studies provided considerable evidence for the model of the intramolecular synergy between the catalytic domain and their CBMs.

关键词： cellulose cellulase cellobiohydrolase cellulose binding module hydrogen bonds molecular dynamics simulation

PARALLEL CHAOTIC MULTISPLITTING ITERATIVE METHODS FOR THE LARGE SPARSE LINEAR COMPLEMENTARITY PROBLEM

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Journal of Computational Mathematics 2001年第3期19卷 281-292页

作者： Zhong-zhi Bai (State Key laboratory of Scientific/Engineering Competing institute of Computational Mathematics and Scientific/Engineering Computing, academy of Mathematics and Systems sciences, chinese academy of sciences, beijing 100080, china) 中科院计算数学与工程计算数学所科学与工程计算国家重点实验室北京 100080

Focuses on a study which presented a parallel chaotic multisplitting method for solving the large sparse linear complementarity problem. Preliminaries of the study; Equations of the parallel chaotic multisplitting met... 详细信息

关键词： linear complementarity problem matrix multisplitting chaotic iteration relaxed method convergence property

Numerical exploration of new features on three-dimensional transition of a cylinder wake

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Science china Mathematics 2004年第Z1期47卷 69-80页

作者： LING Guocan, XIONG Jun & ZHU KeqinState Key laboratory of Nonlinear Mechanics, institute of Mechanics, chinese academy of sciences, beijing 100080, china Department of Engineering Mechanics, Tsinghua University, beijing 100084, china State Key laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing China Department of Engineering Mechanics Tsinghua University Beijing China

The three-dimensional transition of the wake flow behind a circular cylinder is studied in detail by direct numerical simulations using 3D incompressible N-S equations for Reynolds number ranging from 200 to 300. New features and vortex dynamics of the 3D transition of the wake are found and investigated. At Re = 200, the flow pattern is characterized by mode A instability. However, the spanwise characteristic length of the cylinder determines the transition features. Particularly for the specific spanwise characteristic length linear stable mode may dominate the wake in place of mode A and determine the spanwise phase difference of the primary vortices shedding. At Re = 250 and 300 it is found that the streamwise vortices evolve into a new type of mode "dual vortex pair mode" downstream. The streamwise vortex structures switch among mode A, mode B and dual vortex pair mode from near wake to downstream wake. At Re = 250, an independent low frequency fm in addition to the vortex shedding frequency fs is identified. Frequency coupling between fm and fs occurs. These result in the irregularity of the temporal signals and become a key feature in the transition of the wake. Based on the formation analysis of the streamwise vorticity in the vicinity of cylinder, it is suggested that mode A is caused by the emergence of the spanwise velocity due to three dimensionality of the incoming flow past the cylinder. Energy distribution on various wave numbers and the frequency variation in the wake are also described.

关键词： cylinder, wake, 3D transition, Fourier-spectral-spectral-element method, direct numerical simulation (DNS).

Markov chain approach to identifying Wiener systems

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Science china(Information sciences) 2012年第5期55卷 1201-1217页

作者： ZHAO WenXiao 1,2 & CHEN HanFu 1,2 1 Key laboratory of Systems and Control,institute of Systems Science,AMSS,chinese academy of sciences,beijing 100190,china 2 national Center for Mathematics and Interdisciplinary sciences,chinese academy of sciences,beijing 100190,china Key laboratory of Systems and Control Institute of Systems Science AMSS Chinese Academy of Sciences Beijing China national Center for Mathematics and Interdisciplinary sciences Chinese Academy of Sciences Beijing China

Identification of the Wiener system composed of an infinite impulse response (IIR) linear subsystem followed by a static nonlinearity is *** recursive estimates for unknown coefficients of the linear subsystem and for the values of the nonlinear function at any fixed points are given by the stochastic approx-imation algorithms with expanding truncations (SAAWET).With the help of properties of the Markov chain connected with the linear subsystem,all estimates derived in the paper are proved to be strongly *** comparison with the existing results on the topic,the method presented in the paper simplifies the convergence analysis and requires weaker conditions.A numerical example is given,and the simulation results are consistent with the theoretical analysis.

关键词： Wiener system recursive identification stochastic approximation Markov chain strong consis-tency

Systematic study of survival probability of excited superheavy nuclei

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Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 109-113页

作者： XIA ChengJun1, SUN BaoXi1, ZHAO EnGuang2,3 & ZHOU ShanGui2,3 1College of Applied sciences, beijing University of Technology, beijing 100124, china 2institute of Theoretical physics, chinese academy of sciences, beijing 100190, china 3Center of Theoretical Nuclear physics, national laboratory of Heavy Ion Accelerator, Lanzhou 730000, china College of Applied sciences Beijing University of Technology Beijing China institute of Theoretical physics Chinese Academy of Sciences Beijing China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou China

The stability of excited superheavy nuclei (SHN) with 100 Z 134 against neutron emission and fission is investigated by using a statistical model. In particular, a systematic study of the survival probability against fission in the 1n-channel of these SHN is made. The present calculations consistently take the neutron separation energies and shell correction energies from the calculated results of the finite range droplet model which predicts an island of stability of SHN around Z = 115 and N = 179. It turns out that this island of stability persists for excited SHN in the sense that the calculated survival probabilities in the 1n-channel of excited SHN at the optimal excitation energy are maximized around Z = 115 and N = 179. This indicates that the survival probability in the 1n-channel is mainly determined by the nuclear shell effects.

关键词： survival probability superheavy elements island of stability neutron emission fission