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Interface delamination of the thermal barrier coating subjected to local heating

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Science china(Technological sciences) 2010年第12期53卷 3168-3174页

作者： WU ChenWu, HUANG ChenGuang & CHEN GuangNan institute of Mechanics, chinese academy of sciences, beijing 100190, china institute of Mechanics Chinese Academy of Sciences

To investigate the possible failure modes of the thermal barrier coating (TBC) used to protect the scramjet combustion chamber, the local heating via laser beam irradiation was utilized to simulate the service condition of high thermal flux and high temperature gradient. Firstly, the experimental method and process were described and the typical fracture morphology of the TBC under test were provided. Then, the theoretical and finite element modeling were carried out to study the temperature, deformation and stresses of the specimen when the top ceramic coat was subjected to local heating, and to demonstrate the mechanism on the failure of the TBC. It is revealed that the interface delamination shall appear and ultimately lead to the failure of the TBC under such thermal loading of local quick heating. According to the outcome of this study, the driving force of the interface delamination is influenced greatly by the key structural parameters and performance matching. Moreover, by utilizing the rules of the effects of these parameters on the fracture driving force, there is some possibility for the designer to optimize the performances of the TBC.

关键词： TBC local heating interface delamination FE modeling

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

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 chinese academy of sciences Institute of High Energy Physics Beijing China (GRID:grid.9227.e) (ISNI:***)

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

The lepton flavor violating signal of the extra gauge boson Z′in photon-photon collision at the ILC

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Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 1992-1997页

作者： LIU GuoLi 1,2 1 physics Department,Zhengzhou University,Zhengzhou 450001,china 2 Kavli institute for Theoretical physics china,chinese academy of sciences,beijing 100190,china Zhengzhou University Physics Department Zhengzhou China (GRID:grid.207374.5) (ISNI:***) chinese academy of sciences Kavli Institute for Theoretical Physics China Beijing China (GRID:grid.9227.e) (ISNI:***)

The hitherto unconstrained lepton flavor mixings,induced by the new gauge boson Z ,which are the prediction of many new physics models,such as topcolor-assisted technicolor (TC2) models and flavor-universal TC2 models,may lead to the lepton flavor violating productions of τμˉ,τeˉ and μeˉ in photon-photon collision at the proposed International Linear Collider (ILC).Through a comparative analysis of these processes,we find that the better channel to probe the new physics models is the production of τμˉ or τeˉ which occurs at a much higher rate than μeˉ production due to the large mixing angle and the large flavor changing coupling,and may reach the detectable level of the ILC for a large part of the parameter *** the rates predicted by the Standard Model are far below the detectable level,these processes may serve as a sensitive probe for such new physics models.

关键词： new gauge boson Z lepton flavor violating processes photon-photon

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

Anti-saturation block adaptive quantization algorithm for SAR raw data compression over the whole set of saturation degrees

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Progress in Natural Science:Materials International 2009年第8期19卷 1003-1009页

作者： Haiming Qi , Weidong Yu institute of Electronics, chinese academy of sciences, beijing 100190, china institute of Electronics Chinese Academy of Sciences Beijing 100190 China

In order to improve the performance of block adaptive quantization (BAQ) when the output of the analog to digital converter (ADC) is saturated, this paper proposes an anti-saturation BAQ algorithm. First, the concept of the standard deviation of the output signal (SDOS) of the ADC is proposed. Also, unlike traditional normalization processing, SDOS is used and the mapping between SDOS and the average signal magnitude is deduced. Second, the saturation term is introduced to the Lloyd–Max quantizer and an optimal non-uniform scalar quantizer for saturated SAR raw data quantization is proposed. After this, the implementation scheme for the proposed algorithm using an FPGA is analyzed in detail. Third, the relationships among the saturation degree of the signal, the peak-topeak value of the ADC, standard deviation of the input and output signal of the ADC and the average signal magnitude are deduced. Based on these relationships, a power compensation decoder is designed for encoding. Numerical experiment results based on ERS-1 and the simulated data show that the performance of the proposed algorithm is better than that of BAQ.

关键词： Synthetic aperture radar (SAR) Raw data compression Block adaptive quantization (BAQ) Anti-saturation

A 3.9 V polyanion-type cathode material for Li-ion batteries

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Progress in Natural Science:Materials International 2011年第3期21卷 211-215页

作者： Lei LIU,Bin ZHANG,Xue-jie HUANG beijing National Laboratory for Condensed Matter physics, institute of physics,chinese academy of sciences,beijing,100190,china beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences

Monoclinic phase LiFeSO4F was synthesized by a simple fast solid state reaction from the mixture of FeSO4·7H2O and LiF pulverized by high energy ball milling.m-LiFeSO4F was confirmed by GITT measurement to be a 3.9 V polyanion-type cathode materials for Li-ion *** electrochemical activity can be enhanced by addition of carbon.A discharge capacity of 105 mA·h/g (70%of theoretical value) was achieved for a m-LiFeSO4F/CNT *** separation behavior during lithium extraction and insertion was observed by ex-situ XRD test.

关键词： LiFeSO4F polyanion cathode Li-ion battery

Investigation on the skewness for independent component analysis

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Science china(Information sciences) 2011年第4期54卷 849-860页

作者： LIU ZhiYong & QIAO Hong institute of Automation,chinese academy of sciences,beijing 100190,china institute of Automation Chinese Academy of Sciences

Skewness has received much less attention than kurtosis in the independent component analysis (ICA).In particular,the skewness seems to become a useless statistics after the kurtosis related one-bit-matching theorem was ***,as the non-Gaussianity of one signal comes mainly from skewness,it is intuitively understandable that its recovery should not rely on *** this paper we discuss the skewness based ICA,and show that any probability density function (pdf) with non-zero skewness can be employed by ICA for the recovery of the source with non-zero skewness,without needing to consider the skewness *** observation together with the one-bit-matching theorem provides a basic guideline for the model pdf design in ICA algorithm.

关键词： independent component analysis skewness kurtosis one-bit-matching theorem

Effects of cosmological constant on motion of UHECR particles

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Science china(physics,Mechanics & Astronomy) 2005年第1期48卷 44-56页

作者： CHEN Shaoxia & CHANG Zhe institute of High Energy physics, chinese academy of sciences, beijing 100039, china Graduate School of chinese academy of sciences, beijing 100039, china institute of High Energy physics Chinese Academy of Sciences Beijing 100039 China Graduate School Chinese Academy of Sciences Beijing 100039 China

Recent astronomical observations manifest that about two-thirds of the whole energy in the Universe is contributed by a small positive cosmological constant A (> 0). Then, an asymptotically de Sitter spacetime is premised naturally. However, physics in the de Sitter spacetime is very different from that in the Minkowski spacetime. As the first step, a covariant formalism of the kinematics in the de Sitter spacetime is presented here. By solving exactly the equations of motion for a field, we obtain the dispersion relation of a free particle. It is noticed that the dispersion relation is dependent on the degree of freedom of angular momentum of the particle. We show the threshold anomaly of the ultra high energy cosmic ray disappears naturally in the framework of the de Sitter kinematics.

关键词： ultrahigh energy cosmic ray, cosmological constant, curved spacetime.