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Research on the slope spectrum of the Loess Plateau

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Science China(Technological Sciences) 2008年第S1期51卷 175-185页

作者： TANG GuoAn,LI FaYuan,LIU XueJun,LONG Yi & YANG Xin Key Laboratory of Virtual Geographic Environment,nanjing Normal University,Ministry of Education,nanjing 210046,China nanjing Normal Univ Key Lab Virtual Geog Environm Minist Educ Nanjing 210046 Peoples R China

A new concept dealing with digital analysis of loess terrain,slope spectrum,is presented and discussed in this paper,by introducing its characteristic,represen-tation and extracting method from DEMs. Using 48 geomorphological units in dif-ferent parts of the loess as test areas and 5 m-resolution DEMs as original test data,the quantitative depiction and spatial distribution of slope spectrum in China's Loess Plateau have been studied on the basis of a series of carefully-designed experiments. In addition,initial experiment indicates a strong relationship between the slope spectrum and the loess landform types,displaying a potential importance of the slope spectrum in geomorphological studies. Based on the slope spectrums derived from the 25 m-resolution DEM data in whole loess terrain in northern part of Shaanxi,13 slope spectrum indices were extracted and integrated into a compre-hensive layer with image integration method. Based on that,a series of unsuper-vised classifications was applied in order to make a landform classification in northern Shaanxi Loess Plateau. Experimental results show that the slope spec-trum analysis is an effective method in revealing the macro landform features. A continuous change of slope spectrum from south to north in northern Shaanxi Loess Plateau shows an obvious spatial distribution of different loess landforms. This also proves the great significance of the slope spectrum method in describing the terrain roughness and landform evolution as well as a further understanding on landform genesis and spatial distribution rule of different landforms in the Loess Plateau.

关键词： Loess Plateau slope spectrum slope DEM loess landform

A new pteridinedione from Whitmania pigra

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Chinese Chemical Letters 2010年第5期21卷 603-605页

作者： Yun Feng Zheng,Cun Yu Li,Guo Ping Peng,Hong Yang Li College of Pharmacy,nanjing University of Chinese Medicine,nanjing 210046,China [a] College of Pharmacy Nanjing University of Chinese Medicine Nanjing 210046 China

A new compound,6-methylsulfinylthieno[3,2-g]-2,4(1H,3H)-pteridinedione,was isolated from the water extract of Whitmania pigra *** structure was elucidated on the basis of NMR and ESIMS spectra.

关键词： Whitmania pigra Heterocycle 6-Methylsulfinylthieno[3,2-g]-2,4(1H,3H)-pteridinedione

Triazatruxene-containing hyperbranched polymers:Microwave-assisted synthesis and optoelectronic properties

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Science China Chemistry 2010年第12期53卷 2472-2480页

作者： LAI WenYong,LIU Dong & HUANG Wei Key Laboratory for Organic Electronics & Information Displays (KLOEID) Institute of Advanced Materials (IAM),nanjing University of Posts & Telecommunications,nanjing 210046,China 1. Key Laboratory for Organic Electronics & Information Displays (KLOEID) Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications Nanjing 210046 China

Hyperbranched polymer structures represent a class of high-functionality building blocks with excellent three-dimensional topology for the construction of highly substituted conjugated *** this contribution,an efficient microwave synthesis protocol toward the synthesis of conjugated hyperbranched polymers is presented.A novel series of soluble hyperbranched polyfluorenes (PTF1-PTF3) incorporating triazatruxene moiety as the branch units with various branching degrees have thus been successfully constructed with good yields and high molecular weight via a facile "A2+B2+C3" *** structures of the hyperbranched polymers were confirmed by NMR and *** thermal,optical,and electrochemical properties of the hyperbranched polymers were also *** results showed that introduction of triazatruxene units into the hyperbranched structure endowed the polymer with good thermal stability and highly amorphous *** investigation of PTFx revealed strong blue emission in both solution and solid *** polymers with higher degree of branching and proper content of linear fluorene units exhibited better photophysical properties in terms of narrow emission spectra and relatively high quantum efficiency as well as improved thermal spectral *** triazatruxene branching unit also played a role in raising the HOMO energy levels relative to those of polyfluorenes that would help to improve the charge injection and transport *** incorporation of triazatruxene unit into hyperbranched polymers has thus explored an effective avenue for constructing optoelectronic polymers with improved functional characteristics.

关键词： hyperbranched polymers microwave synthesis triazatruxene polyfluorene blue emission

Organic thin-film solar cells:Devices and materials

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Science China Chemistry 2012年第4期55卷 553-578页

作者： LI ZhiGang1, ZHAO XinYan2, LI Xin1,2, GAO ZhiQiang1, MI BaoXiu1 & HUANG Wei2 1Jiangsu Engineering Centre for Flat-Panel Displays & Solid-state Lighting and School of Materials Science & Engineering, nanjing University of Posts & Telecommunications, nanjing 210046, China 2Key Laboratory for Organic Electronics & Information Displays (KLOEID) Institute of Advanced Materials (IAM), nanjing University of Posts & Telecommunications, nanjing 210046, China 1. Jiangsu Engineering Centre for Flat-Panel Displays & Solid-state Lighting and School of Materials Science & Engineering Nanjing University of Posts & Telecommunications Nanjing 210046 China2. Key Laboratory for Organic Electronics & Information Displays (KLOEID) Institute of Advanced Materials (IAM) Nanjing University of Posts & Telecommunications Nanjing 210046 China

In recent years, the performance of organic thinfilm solar cells has gained rapid progress, of which the power conversion efficiencies （r/p） of 3%-5% are commonly achieved, which were difficult to obtain years ago and are improving steadily now. The r/p of 7.4% was achieved in the year 2010, and r/p of 9.2% was disclosed and confirmed at website of Mitsubishi Chemical in April, 2011. The promising future is that the r/p of 10% is achievable according to simulation results. Apparently, these are attributed to material innovations, new device structures, and also the better understanding of device physics. This article summarizes recent progress in organic thinfilm solar cells related to materials, device structures and working principles. In the device functioning part, after each brief summary of the working principle, the methods for improvements, such as absorption increment, organic/electrode interface engineering, morphological issues, are addressed and summarized accordingly. In addition, for the purpose of increasing exciton diffusion efficiency, the benefit from triplet exciton, which has been proposed in recent years, is highlighted. In the active material parts, the chemical nature of materials and its impact on device performance are discussed. Particularly, emphasis is given toward the insight for better understanding device physics as well as improvements in device performance either by development of new materials or by new device architecture.

关键词： organic – solar cell – photovoltaic – devices – materials

A three level linearized compact difference scheme for the Cahn-Hilliard equation

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Science China Mathematics 2012年第4期55卷 805-826页

作者： LI Juan 1,2 ,SUN ZhiZhong 1,& ZHAO Xuan 1 1 Department of Mathematics,Southeast University,nanjing 210096,China 2 Yingtian College,nanjing 210046,China 1. Department of Mathematics Southeast University Nanjing 210096 China2. Yingtian College Nanjing 210046 China

This article is devoted to the study of high order accuracy difference methods tor the Cahn-rnmara equation. A three level linearized compact difference scheme is derived. The u^ique solvability and uaconditional convergence of the difference solution are proved. The convergence order is O（T2＋h4） in the maximum norm. The mass conservation and the non-increase of the total energy are also verified. Some numerical examples are given to demonstrate the theoretical results.

关键词： Cahn-Hilliard equation compact difference scheme convergence solvability conservation energynon-increase

AN EQUIVALENCY CONDITION OF NONSINGULARITY IN NONLINEAR SEMIDEFINITE PROGRAMMING

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Journal of Systems Science & Complexity 2010年第4期23卷 822-829页

作者： Chengjin LI Wenyu SUN Raimundo J. B. de SAMPAIO School of Mathematical Sciences Nanjing Normal and Computer Science Fujian Normal University Wenyu SUN University Nanjing 210046 China School of Mathematics Fuzhou 350007 China School of Mathematical Sciences Nanjing Normal University Nanjing 210046 China Pontifical Catholic University of Parana ( PUCPR) Graduate Program in Production and Systems Engineering (PPGEPS) CEP 81611-970 Curitiba Parana Brazil

In this paper,an equivalency condition of nonsingularity in nonlinear semidefinite programming,which can be viewed as a generalization of the equivalency condition of nonsingularity for linearsemidefinite programming,... 详细信息

关键词： Equivalency condition of nonsingularity nonlinear semidefinite programming semidefinite programming.

ENSO signals and their spatial-temporal variation characteristics recorded by the sea-level changes in the northwest Pacific margin during 1965-2005

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Science China Earth Sciences 2009年第5期52卷 869-882页

作者： YUAN LinWang,YU ZhaoYuan,XIE ZhiRen,SONG ZhiYao & Lü GuoNian School of Geographical Science,nanjing Normal University,nanjing 210046,China School of Geographical Science Nanjing Normal University Nanjing 210046 China

Sea-level is closely linked to the Earth's climate and its change is important as a metric for global and regional climate change. Identifying, extracting, and revealing such information through detailed analysis is the prerequisite for understanding the mechanisms of sea-level change. The monthlyaverage tide-change records reported and examined in this paper are from 10 tide gauge stations distributed in the northwest margin of the Pacific Ocean, registered during the period 1965-2005. In particular, we have utilized the Second Order Blind Identification (SOBI) method to identify and the Empirical Mode Decomposition (EMD) method to extract the El Nio-Southern Oscillation (ENSO) signals imprinted in those tide gauge records; and subsequently, we have investigated the spa-tial-temporal characteristics of the extracted ENSO signals using wavelet analysis methods. The following results are obtained: (1) the ENSO events recorded by each tide gauge series are of different types and intensity, which show considerable temporal-spatial variation characteristics, with sea-level responses to ENSO signals remarkably stronger in low latitude areas than in medium-high latitude areas; (2) due to the influences of ocean currents, topographical conditions, and other factors, there exist variations in the type of relationship between the sea-level changes and the recorded ENSO events at different latitudes; (3) sea-level changes can also denote scale-variation characteristics of ENSO events, and particularly, since 1980s, all the tide gauges located south of Kanmen show intense responses to ENSO and the timescale of ENSO events extended gradually from around 4 years to 2-8 years, reflecting variations in the intensity and frequency of ENSO events; and (4) reverse changes of certain scale were noted before and after strong ENSO events recorded by sea-level changes, supporting the research findings about the interaction (mutual coupling and superimposition) between the probability of

关键词： sea level change ENSO SOBI cross wavelet spectrum wavelet coherence

同方期刊数据库

A relative local variational principle for topological pressure

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Science China Mathematics 2010年第6期53卷 1491-1506页

作者： MA XianFeng1,CHEN ErCai2,3,& ZHANG AiHua2,4 1Department of Mathematics,East China University of Science and Technology,Shanghai 200237,China 2School of Mathematics and Computer Science,nanjing Normal University,nanjing 210097,China 3Center of Nonlinear Science,nanjing University,nanjing 210093,China 4College of Mathematics and Physics,nanjing University of Posts and Telecommunications,nanjing 210046,China 1. Department of Mathematics East China University of Science and Technology Shanghai 200237 China2. School of Mathematics and Computer Science Nanjing Normal University Nanjing 210097 China3. Center of Nonlinear Science Nanjing University Nanjing 210093 China4. College of Mathematics and Physics Nanjing University of Posts and Telecommunications Nanjing 210046 China

We define the relative local topological pressure for any given factor map and open cover,and prove the relative local variational principle of this *** precisely,for a given factor map π:(X,T)→(Y,S) between two topological dynamical systems,an open cover U of X,a continuous,real-valued function f on X and an S-invariant measure ν on Y,we show that the corresponding relative local pressure P(T,f,U,y) satisfies sup μ∈M(X,T){ hμ(T,U|Y)+∫X f(x)dμ(x) :πμ=ν}=∫Y P(T,f,U,y)dν(y),where M(X,T) denotes the family of all T-invariant measures on ***,the supremum can be attained by a T-invariant measure.

关键词： pressure conditional entropy relative local variational principle

Estimation of suspended sediment concentration based on bio-optical mechanism and HJ-1 image in Chaohu Lake

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Science China Earth Sciences 2010年第S1期53卷 58-66页

作者： WANG Qiao1,2,JIN Xin2,LI YunMei2,WU ChuanQing1,Lü Heng2,WANG YanFei2,ZHANG Hong2,YIN Bin2 & ZHU Li1 1Satellite Environment Center,Ministry of Environmental Protection,Beijing 100029,China 2Key Laboratory of Virtual Geographic Environment of Education Ministry,nanjing Normal University,nanjing 210046,China 1. Satellite Environment Center Ministry of Environmental Protection Beijing 100029 China2. Key Laboratory of Virtual Geographic Environment of Education Ministry Nanjing Normal University Nanjing 210046 China

Synchronization experiment was conducted in June,2009 to get Inherent Optical Properties(IOP) of water component in Chaohu *** bio-optical mechanism was studied combined with multispectral data of Environmental Satellite 1(CCD),and then inversion models of total suspended matter(TSM),inorganic suspended matter(ISM) and organic suspended matter(OSM) concentration were *** data indicated that:the absorption ratio of suspended particulate matter and CDOM to total were almost no change from band 1 to band 2 with about 85% and 9%,*** ratio of pure water to total increased from 0.4% to 5.6%.Water reflectance in these two bands were influenced by absorption of three kinds of components:algae particles absorption surpassed non-algal particles in band 3,and so played an important role in total absorption with about 35.7%;the proportion of pure water absorption and particles matter backscattering both were 99% in band 4,so these two components decided the main inherent optical properties in band *** models of TSM and ISM concentration inversion based on band combination(band 3 + band 4)/(band 1 + band 2) were built,while OSM concentration was estimated by band 4/(band 1 + band 2) *** by image data,RE of TSM concentration between modeled and measured was 33.4%,and RMSE was 18.68 mg/*** of ISM and OSM concentration were 39.9% and 35.2% *** inversion was more accurate when satellite-ground data were just in the same *** this situation,RE of ISM concentration dropped to 25.4%,and that of TSM and OSM reduced to 26.5% and 26.8% as well.

关键词： HJ-1 Satellite bio-optical property Chaohu Lake suspended matter