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Electrochemical properties and interfacial reactions of LiNi0.5Mn1.5O4-δ nanorods

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Progress in Natural Science:Materials International 2012年第3期22卷 207-212页

作者： Liping Wang, Hong Li, Xuejie Huang institute of physics, chinese academy of sciences, beijing 100190, china institute of physics Chinese Academy of Sciences Beijing 100190 China

LiNi0.5Mn1.5O4-δ which possesses a high voltage of 4.7 V vs. Lit/Li and stable structure has been considered as a promising cathode material for high energy Li-ion batteries. In this study, well-crystallized LiNi0.5Mn1.5O4-δ nanorods with diameter of ～50 nm and length of ～500 nm were synthesized by a hydrothermal-solid state process followed by a lithiation reaction. It delivers ～120 mA h-g 1 discharge capacity under 30 mA g-1 at 3.5-4.9 V, and 90 mA h g-1 at 150 mA g-1. An unstable solid electrolyte interphase (SEI) film with thickness 2-10 nm was observed by transmission electron microscopy. The thick and unstable SEI layers are responsible for its low rate performance and low coulombic efficiency during cycling.

关键词： Lithium ion battery High voltage spinel Nanorods Surface reaction

From quantum spectra to classical orbits: Varying rectangular billiards

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Progress in Natural Science:Materials International 2008年第8期18卷 927-930页

作者： Jun Lu * Department of Foundational Science, beijing Union University, beijing 100101, china institute of theoretical physics, chinese academy of sciences, beijing 100080, china Department of Foundational Science Beijing Union University Beijing 100101 China institute of theoretical physics Chinese Academy of Sciences Beijing 100080 China

The quantum-spectrum function is introduced by means of the eigenvalues and the eigenfunctions in the system of varying rectangular billiards. It is found that the Fourier transform of the quantum-spectrum function corresponds with the classical orbits in the system. These results give new evidence about the classical-quantum correspondence.

关键词： Quantum spectrum Classical-quantum correspondence Semiclassical physics

The solid lubricating material experiment device for Shenzhou-7 Spaceship

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Science china(Technological sciences) 2010年第9期53卷 2521-2527页

作者： WANG Ke1,2,REN WeiJia1,WANG ShiDa1 & WENG LiJun3 1 academy of Opto-Electronics,chinese academy of sciences,beijing 100190,china 2 Graduate University of chinese academy of sciences,beijing 100049,china 3 Lanzhou institute of Chemical physics,chinese academy of sciences,Lanzhou 730000,china academy of Opto-Electronics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Lanzhou institute of Chemical physics Chinese Academy of Sciences Lanzhou China

A solid lubricating material exposure experiment in space is one of the missions during the seventh manned spaceflight of china,and the key is to develop a device which can be fixed reliably outside of the orbital module and can be fetched conveniently by an astronaut during space *** solid lubricating material experiment device needs to be locked reliably in a vibrating and impacting environment during the launch phase,and should meet the requirement that it can be unlocked and fetched reliably by the astronaut wearing an extravehicular spacesuit via simple operations in orbit in an environment of high and low *** for the device we developed,the environmental characteristic of the mission was analyzed,the mechanical analysis and thermal analysis were carried out,and then a mechanism with functions of mechanical locking,structural self-locking and manual unlocking was *** device was verified by a sequence of experiments and was fetched by the astronaut during the flight of the Shenzhou-7 Spaceship.

关键词： manned spaceflight exposure experiment mechanism unlock

Onset of cavitation by the strong tension spike from a tube-arrest apparatus

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 301-305页

作者： YING ChongFu & LI Chao institute of Acoustics,chinese academy of sciences,beijing 100190,china institute of Acoustics Chinese Academy of Sciences Beijing China

Our earlier paper has identified a wave of Type 1 that is the pressure wave generated in the liquid-filled glass tube through the tube-arrest method by pulling and arresting the tube,when cavitation is prohibited. If cavitation is produced,a wave of Type 2 generally appears. The present paper takes the transition between wave types as indication of cavitation onset,and looks for a liquid parameter which controls the onset. One such an attempt shows the concentration of a dissolved gas in the liquid is the controlling factor with the result that the threshold of cavitation onset decreases with the increase of the concentration. Then a specially designed experiment reveals that possibly the mobility of the gas molecules (and also that of the liquid molecules) transiently affects the threshold so as to induce a large rise and fall in time of hours. The threshold finally settles down to some stable value under atmospheric pressure.

关键词： tube-arrest method cavitation onset controlling parameter concentration of dissolved gas mobile gas molecules liq-uid tensile strength

Effect of internal bubbly flow on pipe vibrations

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Science china(Technological sciences) 2010年第2期53卷 423-428页

作者： ZHANG MingMing & XU JianZhong institute of Engineering Thermophysics, chinese academy of sciences, beijing 100190, china institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China

This paper presents an experimental investigation on wall vibrations of a pipe due to injection of a uniform bubble cloud into the pipe flow. For different bubble void fractions and averaged bubble sizes, the vibrations were measured using accelerometers. To understand the underlying physics, the evolution of the vibration spectra along the streamwise direction was examined. Results showed that wall vibrations were greatly enhanced up to 25 dB, compared with no bubble case. The characteristics of the vibration were mainly dependent on void fraction. These vibrations were believed to be caused by two mechanisms: acoustic resonance and normal modes of the bubble cloud. The former, originating from the interaction between the first mode of the bubble cloud and the first acoustic mode of the pipe, persisted along the entire pipe to enhance the vibration over a broad band frequency range, while the later, due to the process of bubble formation, successively decayed in the streamwise direction.

关键词： pipe vibration bubbly flow acoustic resonance normal mode decay rate

Finding Signals for Plant Promoters

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Genomics, Proteomics & Bioinformatics 2003年第1期1卷 68-73页

作者： Weimou Zhenginstitute of theoretical physics, chinese academy of sciences, beijing 100080, china beijing Genomicsinstitute, chinese academy of sciences, beijing 101300, china institute of theoretical physics Chinese Academy of Sciences Beijing 100080 China beijing Genomics institute Chinese Academy of Sciences Beijing 101300 China

The strongest signal of plant promoter is searched with the model of single motif with two types. It turns out that the dominant type is the TATA-box. The other type may be called TATA-less signal, and may be used in gene finders for promoter recognition. While the TATA signals are very close for the monocot and the dicot, their TATA-less signals are significantly different. A general and flexible multi-motif model is also proposed for promoter analysis based on dynamic programming. By extending the Gibbs sampler to the dynamic programming and introducing temperature, an efficient algorithm is developed for searching signals in plant promoters.

关键词： for on is as et Pro Finding Signals for Plant Promoters been of into

Studies on BEPC upgrade from pretzel to double-ring

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Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 2084-2089页

作者： ZHANG Chuang institute of High Energy physics,chinese academy of sciences,beijing 100049,china institute of High Energy physics Chinese Academy of Sciences Beijing China

physics opportunity in the charm and τ energy region calls for higher luminosity of the beijing Electron-Positron Collider (BEPC).The BEPC has experienced continuous improvement since its completion in ***,as a major upgrading project of the BEPC,aims at enhancing its luminosity of factor 30–100,following the principle of "one machine,two purposes" as adopted in BEPC,so that both high energy physics and synchrotron radiation experiments can be carried out with *** the BEPC to BEPCII,the double-ring scheme with multi-bunch e +-e-collision in the large crossing angle was studied in comparison with the single-ring pretzel *** the dedicated synchrotron radiation operation,artful "bridges" are designed to connect two halves of the outer ring in both the southern and the northern crossing *** paper reviews the studies on the BEPC upgrade from pretzel to double-ring structure of BEPCII.

关键词： collider storage ring high energy physics synchrotron radiation

Recent beijing Spectroscopy (BES) results

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Science china(physics,Mechanics & Astronomy) 2008年第6期51卷 567-576页

作者： LI WeiGuo institute of High Energy physics, chinese academy of sciences, beijing 100049, china institute of High Energy physics Chinese Academy of Sciences Beijing China

Recent experimental results from beijing Spectroscopy (BES) are reviewed, including the hadron spectroscopy from J/ψ decays, and a number of new states are found or confirmed, including σ, κ, X(1835), ωφ threshold enhancement in J/ψ→γωφ, a broad resonance in J/ψ→K + K ? π 0, decay studies of ψ(2S) and χ CJ , as well as the results of ψ(3770) non-D $ \bar D $ decays. The current status of BEPCII/BESIII, the major upgrade of BEPC/BESII, is also reported.

关键词： beijing Spectroscopy hadron spectroscopy charm physics BEPCII

The mechanism of the effects of the upwelling mean on the ENSO event mature phase locking

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Science china Earth sciences 2007年第8期50卷 1266-1272页

作者： YAN BangLiang CMSR, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china CMSR Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The mechanism of the effects of the upwelling mean on the ENSO event mature phase locking is ex-amined by using a mixed-mode model. The results show that the positive feedback process of the ef-fects of the seasonal variation of the upwelling mean on the Kelvin wave is the mechanism of the locking of the event mature phase to the end of the calendar year. The memory of the Rossby waves for the sign-shifting of the sea surface temperature anomaly from positive to negative 6 months before the cold peak time is the other mechanism of the locking of the La Nia event mature phase to the end of the calendar year. The results here are different from previous ones which suggest that the balance between cold and warm trends of sea surface temperature anomaly is the mechanism involved. The cold trend is caused by the upwelling Kelvin wave from upwelling Rossby wave reflected at the western boundary, excited by the westerly anomaly stress over the central Pacific and amplified by the seasonal variation of the coupled strength in its way propagating westward. The warm trend is caused by the Kelvin wave forced by the western wind stress over the middle and eastern equatorial Pacific. The cause of the differences is due to the opposite phase of the seasonal variation of the upwelling mean to that in the observation and an improper parameterization scheme for the effects of the seasonal varia-tion of the upwelling mean on the ENSO cycle in previous studies.

关键词： Kelvin wave Rossby wave interaction between atmosphere and sea positive feedback