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A modeling study of relation between cloud amount and SST over Western Tropical Pacific cloudy regions during TOGA COARE

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Progress in Natural science:Materials International 2009年第2期19卷 187-193页

作者： Shouting Gaoa,Xiaopeng Cui a,Xiaofan Li b a Laboratory of Cloud-Precipitation physics and Severe Storms (LACS),Institute of Atmospheric physics,chinese academy of sciences,beijing 100029,china b Joint center for Satellite Data Assimilation and NOAA/NESDIS/center for Satellite Applications and Research,Camp Springs,MD,USA [a]Laboratory of Cloud-Precipitation physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China [b]Joint Center for Satellite Data Assimilation and NOAA/NESDIS/Center for Satellite Applications and Research Camp Springs MD USA

The relationship between cloud amount and sea surface temperature (SST) over Western Tropical Pacific cloudy regions during TOGA COARE is investigated based on hourly grid simulation data from a two-dimensional coupled ocean-cloud resolving atmosphere model. The model is forced by the large-scale vertical velocity and zonal wind observed and derived from TOGA COARE for a 50-day period. The cloud amount becomes smaller when the ocean surface gets warmer,which is similar to previous relations obtained from observational analyses. As SST increases,the atmospheric temperature increases whereas the surface sensible heat flux decreases. The atmospheric water vapor is not sensitive to SST whereas the surface evaporation flux decreases as SST increases. These indicate that the oceanic effects do not play an important role in determining atmospheric heat and water vapor budgets. The cold atmosphere pro-duces a larger amount of ice clouds that cover a larger area than the warm atmosphere does. The large amounts of ice clouds lead to cooling of the ocean surface through reflecting large amount of solar radiation back to the space. Thus,the negative correlation between the cloud amount and SST only accounts for the important atmospheric effects on the ocean.

关键词： Cloud amount Sea surface temperature Coupled ocean-cloud resolving atmosphere model TOGA COARE

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Shape phase transitions in nuclei:Effective order parameters and trajectories

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science china(physics,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 physics 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

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The guanidine hydrochloride-induced denaturation of CP43 and CP47 studied by terahertz time-domain spectroscopy

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science china(Life sciences) 2007年第3期50卷 350-355页

作者： QU YuanGang1,3, CHEN Hua2, QIN XiaoChun1, WANG Li2, LI LiangBi1 & KUANG TingYun1 1 Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, chinese academy of sciences, beijing 100093, china 2 Laboratory of Optical physics, Institute of physics and center for Condensed Matter physics, chinese academy of sciences, beijing 100080, china 3 Graduate University of chinese academy of sciences, beijing 100049, china 1. Key Laboratory of Photosynthesis and Environmental Molecular Physiology Institute of Botany Chinese Academy of Sciences Beijing 100093 China 3. Graduate University of chinese academy of sciences Beijing 100049 China 2. Laboratory of Optical physics Institute of Physics and Center for Condensed Matter Physics Chinese Academy of Sciences Beijing 100080 China

Terahertz time-domain spectroscopy (THz-TDS) is a new technique in studying the conformational state of a molecule in recent years. In this work, we reported the first use of THz-TDS to examine the dena- turation of two photosynthesis membrane proteins: CP43 and CP47. THz-TDS was proven to be useful in discriminating the different conformational states of given proteins with similar structure and in monitoring the denaturation process of proteins. Upon treatment with guanidine hydrochloride (GuHCl), a 1.8 THz peak appeared for CP47 and free chlorophyll a (Chl a). This peak was deemed to originate from the interaction between Chl a and GuHCl molecules. The Chl a molecules in CP47 interacted with GuHCl more easily than those in CP43.

关键词： CP The guanidine hydrochloride-induced denaturation of CP43 and CP47 studied by terahertz time-domain spectroscopy THz time

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Morphologies of Fe-66.7 at.%Si alloy solidified in a drop tube

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science china(physics,Mechanics & Astronomy) 2005年第6期48卷 658-666页

作者： WANG Haiyan1,2, LIU Riping1, MA Mingzhen1, JING Qin1, LI Gong1, SUN Liling2 & WANG Wenkui1,2 1. Key Laboratory of Metastable Materials science & Technology, Yanshan University, Qinhuangdao 066004, china 2. Institute of physics, chinese academy of sciences, beijing 100080, china 1. Key Laboratory of Metastable Materials science & Technology Yanshan University 066004 Qinhuangdao China 2. Institute of physics Chinese Academy of Sciences 100080 Beijing China

Solidification of 0.1―1.0 mm diameter droplets of Fe-66.7 at.%Si alloy was achieved in a 3 m drop tube. The XRD, EDS, and SEM measurements reveal that all the droplets are composed of the primary phase α and the α+ε eutectic. With decreasing droplet diameter, the growth mode of the primary phase α changes from faceted to nonfaceted growth and the eutectic changes from needle-like to anomalous eutectic. In addition, the width of the primary phase α decreases with decreasing droplet size. The different cooling rates and undercooling levels corresponding to the samples with different sizes are responsible for the morphology changes. The cooling rates of the samples with different diameters during free fall were calculated and their effects on the microstructure formation were discussed. This kind of transition is also found inside the same sample, which is due to the larger cooling rate on the surface than at the center.

关键词： Fe-Si alloy, solidification, drop tube, undercooling.

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Anomalous boundary deformation induced by enclosed active particles

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chinese physics B 2017年第10期26卷 82-88页

作者：田文得顾燕郭永坤陈康 center for Soft Condensed Matter physics & Interdisciplinary Research College of Physics Optoelectronics and EnergySoochow University Kavli Institute for theoretical physics china Chinese Academy of Sciences

We simulate a two-dimensional model of a round soft boundary enclosed with self-propelled particles. Persistent motion drives these particles to accumulate near the boundary, thereby dramatically deforming the boundary shape through collisions. Quantitative analyses of the boundary shape and the particle distribution show that there are two typical regimes in the variation of the morphology with the increase of self-propulsion of particles. One is under small forces, characterized by the radially inhomogeneous distribution of particles and the suppression of local fluctuations of the almost round boundary, and the other is under large forces, featured by the angularly inhomogeneous distribution of particles and the global shape deformation of the boundary. These two features are strongly cooperative. We also find different mechanisms in the particle relocation at low and high particle concentrations.

关键词： self-propelled particles boundary active matter confinement

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XMM-Newton observation of the eclipsing binary Algol

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Research in Astronomy and Astrophysics 2011年第4期11卷 457-470页

作者： Xue-Juan Yang Fang-Jun Lu Bemd Aschenbach Li Chen Faculty of Materials Optoelectronics and Physics Xiangtan University Xiangtan 411105China Particle Astrophysics center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Max-Planck-Institut fur Extraterrestrische Physik 85741 Garching Germany Department of Astronomy Beijing Normal University Beijing 100875 China

We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary. The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star. The XMM-Newton European Photon Imaging Camera and Reflection Grating Spectrometer spectra of Algol in its quiescent state are described by a two-temperature plasma model. The cool component has a temperature around 6.4× 106 K while that of the hot component ranges from 2 to 4.0× 107 K. Coronal abundances of C, N, O, Ne, Mg, Si and Fe were obtained for each component for both the quiescent and the flare phases, generally with upper limits for S and Ar, and upper limits for C, N, and O from the hot component. F-tests show that the abundances do not need to be different between the cool and the hot component and between the quiescent and the flare phase with the exception of Fe. Although the Fe abundance of the cool component remains constant at -0.14, the hot component shows an Fe abundance of -0.28, which increases to -0.44 during the flare. This increase is expected from the chromospheric evaporation model. The absorbing column density NH of the quiescent emission is 2.5 - 1020 cm-2, while that of the flare-only emission is significantly lower and consistent with the column density of the interstellar medium. This observation substantiates earlier suggestions of the presence of X-ray absorbing material in the Algol system.

关键词： stars abundance -- star binaries eclipsing -- stars flare -- stars indi-vidual Algol

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theoretical study of the interaction mechanism of single-electron halogen bond complexes H_3C…Br-Y(Y=H,CN,NC,CCH,C_2H_3)

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science china Chemistry 2010年第1期53卷 216-225页

作者： LI ZhiFeng1,SHI XiaoNing1,TANG HuiAn1 & ZHANG JunYan2 1College of Life science and Chemistry,Tianshui Normal University,Tianshui 741001,china 2Lanzhou Institute of Chemical physics,chinese academy of sciences,Lanzhou 730000,china 1. College of Life science and Chemistry Tianshui Normal University Tianshui 741001 China2. Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China

The characteristics and structures of single-electron halogen bond complexes H3C…Br-Y(Y = H,CCH,CN,NC,C2H3) have been investigated by theoretical calculation *** geometries were optimized and frequencies calculated at the B3LYP/6-311++G *** interaction energies were corrected for basis set superposition error(BSSE) and the wavefunctions obtained by the natural bond orbital(NBO) and atom in molecule(AIM) analyses at the MP2/6-311++G *** each H3C…Br-Y complex,a single-electron Br bond is formed between the unpaired electron of the CH3(electron donor) radical and the Br atom of Br-Y(electron acceptor);this kind of single-electron bromine bond also possesses the character of a"three-electron bond".Due to the formation of the single-electron Br bond,the C-H bonds of the CH3 radical bend away from the Br-Y moiety and the Br-Y bond elongates,giving red-shifted single-electron Br bond *** effects of substituents,hybridization of the carbon atom,and solvent on the properties of the complexes have been *** strengths of single-electron hydrogen bonds,single-electron halogen bonds and single-electron lithium bonds have been *** addition,the single-electron halogen bond system is discussed in the light of the first three criteria for hydrogen bonding proposed by Popelier.

关键词： single-electron halogen bond single-electron hydrogen bond single-electron lithium bond MP2 DFT NBO AIM

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A facile and efficient dry transfer technique for two-dimensional Van der Waals heterostructure

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chinese physics B 2017年第8期26卷 417-422页

作者：谢立杜罗军卢晓波杨蓉时东霞张广宇 beijing National Laboratory for Condensed Matter physics and Institute of physics Chinese Academy of Sciences(CAS)Beijing 100190China School of Physical science University of Chinese Academy of SciencesBeijing 100190China Collaborative Innovation center of Quantum Matter Beijing 100190China beijing Key Laboratory for Nanomaterials and Nanodevices Beijing 100190China

Two-dimensional （2D） Van der Waals heterostructures have aroused extensive concerns in recent years. Their fabrica- tion calls for facile and efficient transfer techniques for achieving well-defined structures. In this work, we report a simple and effective dry transfer method to fabricate 2D heterostructures with a clean interface. Using Propylene Carbonate （PC） films as stamps, we are able to pick up various 2D materials flakes from the substrates and unload them to the receiving substrates at an elevated temperature. Various multilayer heterostructures with ultra-clean interfaces were fabricated by this technique. Furthermore, the 2D materials can be pre-pattemed before transfer so as to fabricate desired device structures, demonstrating a facile way to promote the development of 2D heterostructures.

关键词： two-dimensional materials Van der Waals heterostructure Propylene Carbonate transfer

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Identifying heavy hitters in high-speed network monitoring

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science china(Information sciences) 2010年第3期53卷 659-676页

作者： ZHANG Yu1, FANG BinXing1,2 & ZHANG YongZheng2 1Research center of Computer Network and Information Security Technology, Harbin Institute of Technology, Harbin 150001, china 2Research center of Information Security, Institute of Computing Technology, chinese academy of sciences, beijing 100190, china 1. Research center of Computer Network and Information Security Technology Harbin Institute of Technology Harbin 150001 China2. Research Center of Information Security Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China

Identifying heavy hitters in a network traffic stream is important for a variety of network applications ranging from traffic engineering to anomaly detection such as detection of denial-of-service attacks. Existing methods generally examine newly arriving items in the stream, perform a small number of operations using a small amount of memory, and still provide guarantees on the identifying accuracy. In high-speed network monitoring, the update speed per item is extremely critical. However, so far as we know, there are no identifying algorithms which can provide constant update time (O(1)) in a weighted data stream. In this paper, we present an algorithm named Weighted Lossy Counting (WLC) which is able to identify heavy hitters in a high-speed weighted data stream with constant update time. WLC employs a novel efficient partially ordered data structure which is able to provide a fast per-item update speed while keeping the memory cost relatively low. We compare WLC with state-of-the-art algorithms for finding heavy hitters in real traffic traces. The experimental results show that WLC performs well in accuracy (recall, precision and average relative error) as other algorithms; moreover it has a much higher update speed at the cost of relatively larger memory space used. A theoretical worst-case memory bound of WLC is also derived in this paper; however, experiments with long real traffic traces show that WLC requires much less space than the theoretical bound in practice.

关键词： network traffic monitoring heavy hitter weighted data streams

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Use of the advanced microwave sounding unit data to improve typhoon prediction

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Progress in Natural science:Materials International 2009年第3期19卷 369-376页

作者： Guo Deng a,*, Dalin Zhang b, Tong Zhu c, Angsheng Wang d a National Meteorological center, beijing 100081, china b Department of Atmospheric and Oceanic science, University of Maryland, Maryland 20742, USA c Cooperative Institute for Research in the Atmosphere, Colorado State University, Colorado 80523, USA d Institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china [a]National Meteorological center Beijing 100081 China [b]Department of Atmospheric and Oceanic Science University of Maryland Maryland 20742 USA [c]Cooperative Institute for Research in the Atmosphere Colorado State University Colorado 80523 USA [d]Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The effects of incorporating the advanced microwave sounding unit (AMSU-A) data with a modified Zhu-Zhang-Weng vortex- bogussing algorithm on typhoon prediction are examined through the use of the PSU/NCAR Mesoscale Model version 5 (MM5). The AMSU-A data contain the vertical distribution of the retrieved temperature from satellite brightness temperature, with the geopo- tential height and wind fields derived through a series of statistical and diagnostic calculations. The advantages of the modified vortex- bogussing algorithm include the incorporation of realistic asymmetric typhoon structures, the balanced dynamics with the background field, the easiness to implement and the effcient computations. To test the effciency of this vortex-bogussing algorithm, the Typhoon Dan event in 1999 is simulated by incorporating the derived AMSU-A fields into the initial conditions of the MM5 modeling system. Results show significant improvements in the track and intensity of the storm, as compared to the simulation without the AMSU-A data. Therefore, this modified vortex-bogussing algorithm can be easily implemented on any typhoon modeling system, which will improve the real-time forecast of tropical cyclones.

关键词： AMSU Satellite retrieval Typhoon prediction

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