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Glassy metallic plastics

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 409-414页

作者： LI JianFu, WANG JunQiang, LIU XiaoFeng, ZHAO Kun, ZHANG Bo, BAI HaiYang, PAN MingXiang & WANG WeiHua institute of physics, chinese academy of sciences, beijing 100190, china institute of physics Chinese Academy of Sciences Beijing China

This paper reports a class of bulk metallic glass including Ce-, LaCe-, CaLi-, Yb-, and Sr-based metallic glasses, which are regarded as glassy metallic plastics because they combine some unique properties of both plastics and metallic alloys. These glassy metallic plastics have very low glass transition temperature (Tg^25oC to 150oC) and low Young’s modulus (~20 GPa to 35 GPa). Similar to glassy plastics, these metallic plastics show excellent plastic-like deformability on macro-, micro- and even nano-scale in their supercooled liquid range and can be processed, such as elongated, compressed, bent, and imprinted at low temperatures, in hot water for instance. Under ambient conditions, they display such metallic properties as high thermal and electric conductivities and excellent mechanical properties and other unique properties. The metallic plastics have potential applications and are also a model system for studying issues in glass physics.

关键词： glassy metallic plastic synthesizing low Tg thermoplastic properties

A new approach to studying ENSO predictability:Conditional nonlinear optimal perturbation

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chinese Science Bulletin 2003年第10期48卷 1045-1047页

作者： MU Mu & DUAN Wansuo LASG, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

A new approach, the conditional nonlinear optimal perturbation (CNOP) is introduced to study the predictability of El Ni駉-Southern Oscillation (ENSO) using a theoretical coupled ocean-atmosphere model. The differences between CNOP and linear singular vector (LSV) are demonstrated. The results suggest that the nonlinear model and CNOP are superior in determining error growth for studying predictability of the ENSO. In particular, the CNOP approach is used to explore the nature of the 憇pring predictability barrier?in ENSO prediction.

关键词：研究方法非线性最优混乱条件天气预报 ENSO模型海洋大气模型

Forecasting the summer rainfall in North china using the year-to-year increment approach

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Science china Earth sciences 2009年第4期52卷 532-539页

作者： FAN Ke1, LIN MeiJing1,2 & GAO YuZhong3 1 Nansen-Zhu International Research Center, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china 2 Graduate University of the chinese academy of sciences, beijing 100049, china 3 Heilongjiang Meteorological Administration, Harbin 150030, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of the chinese academy of sciences Beijing China Heilongjiang Meteorological Administration Harbin China

A new approach to forecasting the year-to-year increment of rainfall in North china in July-August (JA) is proposed. DY is defined as the difference of a variable between the current year and the preceding year (year-to-year increment). NR denotes the seasonal mean precipitation rate over North china in JA. After analyzing the atmospheric circulation anomalies associated with the DY of NR, five key predictors for the DY of NR have been identified. The prediction model for the DY of NR is established by using multi-linear regression method and the NR is obtained (the current forecasted DY of NR added to the preceding observed NR). The prediction model shows a high correlation coefficient (0.8) between the simulated and the observed DY of NR throughout period 1965-1999, with an average relative root mean square error of 19% for the percentage of precipitation rate anomaly over North china. The prediction model makes a hindcast for 2000-2007, with an average relative root mean square error of 21% for the percentage of precipitation rate anomaly over North china. The model reproduces the downward trend of the percentage of precipitation rate anomaly over North china during 1965-2006. Because the current operational prediction models of the summer precipitation have average forecast scores of 60%-70%, it has been more difficult to forecast the summer rainfall over North china. Thus this new approach for predicting the year-to-year increment of the summer precipitation (and hence the summer precipitation itself) has the potential to significantly improve operational forecasting skill for summer precipitation.

关键词： annual increment North china precipitation prediction prediction skill

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

Evaluation of a 3dVAR system for the South china Sea

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Progress in Natural Science:Materials International 2008年第5期18卷 547-554页

作者： Xianjun Xiao a,b, Dongxiao Wang a, Changxiang Yan c, Jiang Zhu c a LED, South china Sea institute of Oceanology, chinese academy of sciences, Guangzhou 510301, china b NCC, china Meteorological Administration, beijing 100081, china c institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china LED South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China NCC China Meteorological Administration Beijing 100081 China institute of Atmospheric physics Chinese Academy of Sciences Beijing 100029 China

The authors evaluate a three-dimensional variational (3dVAR) system for the South china Sea (SCS) in this study. The assimilation method applied in the system takes into consideration error correlation along each ground track and uses recursive lter for optimiza- tion. Data from three R/V cruises during the spring and summer of 1998 and the summer of 2000 are used to evaluate the system. The root-mean-square error and bias are reduced signi cantly and when the altimeter data are assimilated, the distribution of the error is much closer to the Gaussian distribution. Precipitation and river discharge in the southwestern SCS are reproduced, and the variability of sea surface height is e ciently transferred to the subsurface. The 3dVAR system performs well for each of the three cruises, suggesting that it is steady for routine usage.

关键词： South china Sea Three-dimensional variational data assimilation Recursive lter

Interannual variability of Antarctic Oscillation and its influence on East Asian climate during boreal winter and spring

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Science china Earth sciences 2006年第5期49卷 554-560页

作者： FAN Ke1,2,3 & WANG Huijun2 1. Nansen-Zhu International Research Center, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china 2. Department of Atmospheric Science, Yunnan University, Kunming 650091, china 3. Graduate University of the chinese academy of sciences, beijing 100049, china Nansen-Zhu International Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Department of Atmospheric Science Yunnan University Kunming China Graduate University of the chinese academy of sciences Beijing China

The interannual variability of Antarctic Oscillation (AAO) and its influence on East Asian climate during both boreal winter and spring are addressed. The results show that the positive AAO anomaly decreases the cold activity over East Asia during both boreal winter and spring. AAO-related barotropic meridional teleconnection from Antarctic to Arctic is found through analysis of mean me- ridional circulations. This meridional teleconnection is remarkable over Eurasia during boreal winter and over the Pacific Ocean during boreal spring. The results also show that zonal mean zonal wind at high latitudes in Southern Hemisphere has well positive correlation with that of Eurasia during boreal winter and has negative correlation with Pacific North American teleconnection (PNA) during boreal spring, which again display the meridional teleconnection. Thus, local meridional teleconnection is a possible linkage for interaction of circulations at mid-high latitudes between both hemispheres.

关键词： Antarctic Oscillation, Eurasian west wind, meridional teleconnection, mean meridional circulation.

Two possible mechanisms for vortex self-organization

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Science china Earth sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2, ZHOU Xiuji1 & GAO Shouting3 1. chinese academy of Meteorological sciences, beijing 100081, china 2. Department of Space Information Science, Nanjing University of Information Science and Technology, Nanjing 210044, china 3. institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china Department of Environmental Science Nanjing University of Information Science and Technology Nanjing China chinese academy of Meteorological sciences Beijing China institute of Atmospheric physics Chinese Academy of Sciences Beijing China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

Construction and numerical tests of the multi-conservation difference scheme

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chinese Science Bulletin 2003年第10期48卷 1016-1020页

作者： WANG Bin & JI Zhongzhen LASG, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

A difference scheme with four conservation properties for solving the spherical barotropic shallow water equations is constructed, based on a proper formulae of the equations and a skillful correction on the spatial difference parts of the semi-discrete equations with which the number of the conservation properties of these equations is increased from three to four. Numerical tests are included, and good results are achieved in this study.

关键词：多态守恒差分图解法动力系统正压浅水波方程大气系统数字模型

The influence of moderate ENSO on summer rainfall in eastern china and its comparison with strong ENSO

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chinese Science Bulletin 2008年第5期53卷 791-800页

作者： XUE Feng1 & LIU ChangZheng1,2 1 institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china 2 Graduate University of chinese academy of sciences, beijing 100049, china institute of Atmospheric physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

The 6 major ENSO events since 1979 are classified into the strong and moderate ENSO based on in-tensity. The composite analysis is performed to reveal the influence of ENSO on East Asian summer monsoon (EASM) and summer rainfall in eastern china. It is shown that the influence is changed with the seasonal cycle in summer, with a weaker influence in June and a stronger influence in August, in-dicating a long lagged effect of ENSO on EASM. Besides, the circulation and rainfall anomalies caused by the strong ENSO are also stronger with an earlier starting time, while the influence of the moderate ENSO is evident in August. The composite summer rainfall in eastern china for the moderate ENSO exhibits a northern rainfall pattern, which is totally different from the classical ENSO-type rainfall pat-tern. Based on the composite analysis, two moderate ENSO years with a similar intensity (i.e., 1995 and 2003) are compared. The result shows that, the response of EASM to the moderate ENSO during June and July is, to a certain degree, modulated by the circulation systems in mid-high latitudes of Eurasia and in the Southern Hemisphere, thereby inducing a different rainfall distribution in eastern china. In comparison with the strong ENSO in 1983, it is further revealed that, the strong ENSO plays a dominant role in summer rainfall anomalies in eastern china as well as in controlling the influence of the other factors on EASM. The strong ENSO is therefore different with the moderate ENSO.

关键词：中国东部海洋气象学厄尔尼诺现象东亚季风降雨