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Science china chemistry 2010年第8期53卷 1641-1645页

作者： LIU DongTao1,2,CUI DongMei1 & GAO Wei3 1State Key Laboratory of Polymer Physics and chemistry changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2graduate university of chinese academy of sciences,beijing 100039,china 3School of chemistry,Jilin university,changchun 130012,china State Key Laboratory of Polymer Physics and chemistry changchun institute of applied chemistry Chinese Academy of Sciences Changchun China graduate university of chinese academy of sciences Beijing China School of chemistry Jilin University Changchun China

The aryldiimine NCN-pincer stabilized neodymium dichloride combined with aluminum alkyls established a new type of homogeneous binary neutral Ziegler-Natta catalyst *** system exhibited high activity and high cis-1,4 selectivity for the polymerization of isoprene (Tp=20 °C,98.2%;Tp=-20 °C,> 99%).Such catalytic performances remained under a broad range of polymerization temperatures and monomer-to-neodymium ratios (from 500 to 8000),reaching high number-average molecular weight (Mn=1582 kg/mol) and relatively narrow molecular weight distribution (PDI=1.68),which was,however,influenced by the amount and bulkiness of aluminum *** investigation of the polymerization was performed,which showed the number-average molecular weight of the resultant polyisoprene had an almost linear correlation with the conversion,suggesting,in some degree,the polymerization with this catalytic system was controllable.

关键词： neodymium cis-1 4 selectivity NCN-pincer complex polyisoprene

Seed-mediated growth method for high-quality noble metal nanocrystals

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中国科学:化学 2012年第11期42卷 1646-1646页

作者： NIU WenXin 1,2,ZHANG Ling 1,2 & XU GuoBao 1 1 State Key Laboratory of Electroanalytical chemistry changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2 graduate university of the chinese academy of sciences,beijing 100039,china State Key Laboratory of Electroanalytical chemistry changchun institute of applied chemistry chinese academy of sciences changchun 130022 china graduate university of the chinese academy of sciences beijing 100039 china

This review highlights work from the authors' laboratory on the recent development of seed-mediated growth method for noble metal *** seed-mediated growth method has become one of the most efficient and versatile methods for synthesizing high-quality noble metal *** seed-mediated growth method can separate the nucleation and growth stages of metal nanocrystals,and thus provide better control over the size,size distribution,and crystallographic evolution of metal *** of its high controllability,the seed-mediated growth method is especially promising in providing mechanistic insights into the growth mechanisms of noble metal *** this review,the thermodynamic and kinetic parameters for the nucleation and growth of noble metal nanocrystals are systematically *** understanding of these parameters is *** studies provide useful guidelines for the rational design and synthesis of novel noble metal nanocrystals with high quality.

关键词： crystal growth nanocrystal noble metal shape control seed-mediated growth method

Kumada chain-growth polycondensation as a universal method for synthesis of well-defined conjugated polymers

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Science china chemistry 2010年第8期53卷 1620-1633页

作者： GENG YanHou1,HUANG Li1,2,WU ShuPeng1,2 & WANG FoSong1 1State Key Laboratory of Polymer Physics and chemistry changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2graduate university of chinese academy of sciences,beijing 100049,china State Key Laboratory of Polymer Physics and chemistry changchun institute of applied chemistry Chinese Academy of Sciences Changchun China graduate university of chinese academy of sciences Beijing China

Kumada chain-growth polycondensation (KCGP) is a novel method for the synthesis of well-defined conjugated *** the Ni-catalyst can transfer in an intramolecular process to the propagating chain end,the polymerization follows chain-growth *** this newly developed method,various conjugated polymers,such as polythiophenes,poly(p-phenylene) (PPP),polypyrrole (PPy),and polyfluorene with controlled molecular weights and relatively narrow polydispersities (PDIs),have been ***,the polymerizations for poly(3-alkylthiophene)s (P3ATs),PPP,and PPy exhibited quasi-living characteristics,which allows preparing polymer brushes,fully-conjugated block copolymers,and macroinitiators and macro-reactants for the synthesis of rod-coil block *** the current review,the progress in this new area is summarized.

关键词： chain growth polycondensation conjugated polymers Kumada reaction block copolymers polymer brush

Synthesis and characterization of a pH-sensitive shielding system for polycation gene carriers

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Science china chemistry 2010年第3期53卷 502-507页

作者： XIA JiaLiang1,2,CHEN Jie1,TIAN HuaYu1 & CHEN XueSi1 1Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2graduate university of chinese academy of sciences,beijing 100049,china Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry Chinese Academy of Sciences Changchun China graduate university of chinese academy of sciences Beijing China

To increase the in vivo stability of polycation gene carriers,a pH-sensitive shielding system,γ-benzyl L-glutamate-co-glutamate acid polymer(PGA(60)(60 refers to the molar ratio of glutamate acid in the polymer)),was synthesized and ***(60) showed pH sensitivity at about pH ***(60) shielded the positive charge of DNA/PEI(1:1) *** retardation assay showed that no DNA-strand exchange with PGA(60) occurred after PGA(60) was added to DNA/PEI complexes at different *** cytotoxicity tests demonstrated that neither PGA(60) nor DNA/PEI/PGA(60) ternary complexes had cytotoxicity at the test *** transfection efficiency was improved when the positive charge was partly shielded by PGA(60).Because of the charge repulsion between the surface of cells and ternary complex particles,there was almost no transfection efficiency when the zeta potential of ternary complexes turned to *** of the suitable pH sensitive range,PGA(60) may be a potential shielding system for polycation gene carriers to be used in vivo.

关键词： gene delivery shielding system pH-sensitive polyglutamate

Bioreducible crosslinked low molecular weight branched PEI-PBLG as an efficient gene carrier

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Science china chemistry 2010年第12期53卷 2490-2496页

作者： GUO ZhaoPei 1,TIAN HuaYu 1,XIA JiaLiang 1,2,CHEN Jie 1,LIN Lin 1 & CHEN XueSi 1 1 Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry,chinese academy of sciences,changchun 130022,china 2 graduate university of chinese academy of sciences,beijing 100049,china Key Laboratory of Polymer Ecomaterials changchun institute of applied chemistry Chinese Academy of Sciences Changchun China graduate university of chinese academy of sciences Beijing China

Low molecular weight polyethylenimine-poly(gamma-benzyl L-glutamate) (PEI-PBLG) was crosslinked by N,N'-cystaminebisacrylamide (CBA) to get the polymer named as CBA-PEI-PBLG (CPP).CPP not only inherits PEI-PBLG's amphiphilic advantages,but also possesses reducible *** can complex with DNA to form ***/DNA complex particles were characterized by particle size and zeta potential *** result showed that the complex particles have suitable size and surface charges for gene *** gel retardation assay also prove CBA-PEI-PBLG has proper condensing ability for *** has good reducible property,and also has good biocompatibility because of introducing PBLG *** cytotoxicity of CPP was evaluated using MTT assay,and the results showed CPP has lower cytotoxicity compared with PEI 25 *** transfection properties were characterized in different cells by using plasmid DNA as a *** showed higher transfection efficiencies and lower cytotoxicity in HeLa *** was attributed to bioreducible and biocompatibility properties of the *** results suggested that CPP is a promising low-toxic,highly effective non-viral gene carrier.

关键词： gene carrier transfection cytotoxicity crosslinked

NEW OPTICALLY ACTIVE AROMATIC POLYIMIDES Ⅱ: SYNTHESIS AND PROPERTIES OF OPTICALLY ACTIVE AROMATIC POLYIMIDE BASED ON (R)-(+)-2, 2′-BIS (2-TRIFLUORO-4-AMINOPHENOXY)-1, 1′-BINAPHTHYL

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chinese Journal of Polymer Science 1999年第1期17卷 87-90页

作者： Qi-ding Mi Yu Ma Lian-xun Gao Meng-xian Ding changchun institute of applied chemistry, chinese academy of sciences changchun 130022, china Department of chemistry, Peking university, beijing 100871 中科院长春应用化学所吉林长春 130022 中科院长春应用化学所吉林长春

Optically active (R)-(+)-2, 2' -bis(2 -trifluoro-4 -aminophenoxy)- 1, 1' -binaphthyl was prepared from1, 1'-bi-2-naphthol. The optically active aromatic polyimide was also successfully synthesized. This newpolymer has good solubility, thermal stability etc. Its specific rotation was found to be +174°, and itschiroptical property was also studied.

关键词： Optical activity 1, 1′-Bi-2-naphthol, Polyimide

Modeling diameter distribution of the broadleaved-Korean pine mixed forest on Changbai Mountains of china

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Science china(Technological sciences) 2006年第Z1期49卷 177-188页

作者： WANG Shunzhong, DAI Limin, LIU Guohua, YUAN Jianqiong, ZHANG Hengmin & WANG Qingli institute of applied Ecology, chinese academy of sciences, Shenyang 110016, china graduate university of chinese academy of sciences, beijing 100039, china State Key Lab of Systems Ecology, Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china institute of applied Ecology Chinese Academy of Sciences Shenyang China graduate university of chinese academy of sciences Beijing China State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing China

The broadleaved-Korean pine mixed forest is a native vegetation in the Changbai Mountains, northeast china. The probability density functions including the normal, negative exponential, Weibull and finite mixture distribution, were used to describe the diameter distributions of the species groups and entire forest stand. There is a strong correlation between parameters and mean DBH except the shape parameters in the mixture distribution. The diameter classes of species and entire forest stand showed not negative exponential but normal and "S" distribution. The mixture function was better than normal and Weibull to describe the model distribution. The location parameter had an effect on the estimated frequency in the first diameter class, when the estimated location parameter was bigger than the lower limit of the first diameter class.

关键词： broadleaved-Korean pine mixed forest, diameter distribution, finite mixture distribution.

Estimation of forest volumes by integrating Landsat TM imagery and forest inventory data

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Science china(Technological sciences) 2006年第Z1期49卷 54-62页

作者： GU Huiyan, DAI Limin, WU Gang, XU Dong, WANG Shunzhong &WANG Hui institute of applied Ecology, chinese academy of sciences, Shenyang 110016, china School of Forestry, Northeast Forestry university, Harbin 150040, china State Key Lab of Systems Ecology, Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china graduate university of chinese academy of sciences, beijing 100039, china institute of applied Ecology Chinese Academy of Sciences Shenyang China School of Forestry Northeast Forestry University Harbin China State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

Accurate information about forest volumes is essential for forest management planning. The survey interval of the Forest Resource Inventory of china (FRIC) is too long to meet the demand for timely decision-making required for forest protection, management, and utilization. Analysis of satellite imagery provides good potential for more frequent reporting of forest parameters. In this study, we describe an application of the k-nearest neighbors (kNN) method to Landsat TM imagery for improving estimation of forest volumes. Several spectral features were tested and compared in forest volume estimations, including normalized difference vegetation index, environmental vegetation index, and the combination of the spectral features. The combined index resulted in the most accurate volume estimations. The kNN estimator and the combined index were then used in forest volume estimation. The estimation error (RMSE) of the total volume was44.2%, much lower than those for Larix forest (the RMSE was 51.7%) and those for the Korean pine and broadleaved forests (the estimation errors were over 71.7% and 88.19%,respectively). This preliminary study demonstrates the potential of forest volume estimations with remote sensing data to provide useful information for forest management if only limited ground information is available.

关键词： forest inventory, landsat TM, k-nearest neighbors, spectral extraction.

Effects of the grain size distribution on the temperature-dependent magnetic susceptibility of magnetite nanoparticles

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Science china Earth sciences 2010年第7期53卷 1071-1078页

作者： ZHAO XiangYu1,2 & LIU QingSong1 1 Paleomagnetism and Geochronology Laboratory (SKL-LE), institute of Geology and Geophysics, chinese academy of sciences, beijing 100029, china 2 graduate university of chinese academy of sciences, beijing 100049, china Paleomagnetism and Geochronology Laboratory (SKL-LE) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

Magnetite is an important magnetic remanence carrier in natural samples and therefore is of great interest in paleo-, rock-, and environmental magnetism. The magnetic properties of magnetite depend on many factors, e.g., concentration and grain size distribution (GSD). In this study, we theoretically investigated the temperature-dependent susceptibility (TDS) of magnetite nanoparticles with a lognormal GSD. Results show that the TDS is affected highly by the GSD mainly in three aspects. Firstly, the unblocking process becomes smoother with the increase of distribution width, characterizing as a wider Hopkinson peak on the TDS curve. Secondly, the blocking temperature increases with the increase of the median diameter or/and the distribution width. Thirdly, the maximum susceptibility decreases with the increase of distribution width, and has a logarithmic function relation with the standard deviation of the distribution. As a case study, this model was further applied to the thermal products of the chinese loess/paleosol samples to determine the granulometry of newly-formed magnetite upon heating based on TDS curves. The results demonstrate the fidelity and feasibility of this method to determine the GSD of nano-sized magnetic particles.

关键词： Néel theory temperature dependence of susceptibility grain size distribution

The roles of a decision support system in applying forest ecosystem management in Northeast china

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Science china(Technological sciences) 2006年第Z1期49卷 9-18页

作者： DAI Limin, ZHENG Bofu, Guofan Shao & ZHOU Li State Key Lab of Systems Ecology, Research Center for Eco-Environmental sciences, chinese academy of sciences, beijing 100085, china institute of applied Ecology, chinese academy of sciences, Shenyang 110016, china Department of Forestry and Natural Resources, Purdue university, West Lafayette, IN 47907, USA graduate university of chinese academy of sciences, beijing 100101, china State Key Lab of Systems Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing China institute of applied Ecology Chinese Academy of Sciences Shenyang China Department of Forestry and Natural Resources Purdue University West Lafayette USA graduate university of chinese academy of sciences Beijing China

Forest ecosystems provide a variety of services and forest ecosystem management (FEM) is an effective approach to maximize the services. Because of the complexity of forest ecosystems, the applications of FEM can be facilitated with decision support systems (DSS) that recognize and incorporate ecological and socio-economic variables. With the rapid development of computation and information technologies, DSS have been advanced in many ways. Traditional forest management within a forestry unit in china is planned on a yearly basis. The planning itself remains primarily a verbal concept as there are no quantitative decision-support tools available to translate the concept into forest management actions. For the purposes of FEM at the management level, a forest management DFF, FORESTAR, has been developed under a framework of geographic information system (GIS) and forest models. The paper explained the intelligent modeling mechanisms and demonstrated how the applications of FEM can be strengthened with the applications of FORESTAR.

关键词： forest functions, forested landscapes, forest services, forest models, geographic information systems.