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Science china Chemistry 2010年第3期53卷 519-527页

作者： ZHANG Yu1,2,SUN PeiJian1,2 & GAN ZhiHua1 1CAS Key Laboratory of Engineering Plastics,Institute of Chemistry,chinese academy of sciences,beijing 100190,china 2graduate university of chinese academy of sciences,beijing 100039,china CAS Key Laboratory of Engineering Plastics Institute of Chemistry Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

A series of controllable amphiphilic block copolymers composed of poly(ethylene oxide)(PEO) as the hydrophilic block and poly(ε-caprolactone)(PCL) as the hydrophobic block with the amino terminal group at the end of the PEO chain(PCL-b-PEO-NH2) were *** on the further reaction of reactive amino groups,diblock copolymers with functional carboxyl groups(PCL-b-PEO-COOH) and functional compounds RGD(PCL-b-PEO-RGD) as well as the triblock copolymers with thermosensitive PNIPAAm blocks(PCL-b-PEO-b-PNIPAAM) were *** well-controlled structures of these copolymers with functional groups and blocks were characterized by gel permeation chromatography(GPC) and 1H NMR *** copolymers with functionalized hydrophilic blocks were fabricated into microspheres for the examination of biofunctions via cell culture experiments and in vitro drug *** results indicated the significance of introducing functional groups(e.g.,NH2,COOH and RGD) into the end of the hydrophilic block of amphiphilic block copolymers for biomedical potentials in tissue engineering and controlled drug release.

关键词： amphiphilic block copolymers biodegradable polymers functional terminal group cell growth drug release

Estimating forest aboveground biomass using HJ-1 Satellite CCD and ICESat GLAS waveform data

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Science china Earth sciences 2010年第S1期53卷 16-25页

作者： GUO ZhiFeng1,CHI Hong1,2 & SUN GuoQing1,3 1State Key Laboratory of Remote Sensing Science,Jointly Sponsored by the Institute of Remote Sensing Applications of chinese academy of sciences and beijing Normal university,Institute of Remote Sensing Applications,chinese academy of sciences,beijing 100101,china 2graduate university of chinese academy of sciences,beijing 100049,china 3Department of Geography university of Maryland,College Park,MD 20742,USA State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Institute of Remote Sensing Applications Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China Department of Geography university of Maryland College Park USA

The ecosystem in northeastern china and the Russian Far East is a hotspot of scientific research into the global carbon *** aboveground biomass(AGB) is an important component in the land surface carbon *** this study,using forest inventory data and forest distribution data,the AGB was estimated for forest in Daxinganlin in northeastern china by combining charge-coupled device(CCD) data from the Small Satellite for Disaster and Environment Monitoring and Forecast(HJ-1) and Geoscience Laser Altimeter System(GLAS) waveform data from the Ice,Cloud and land Elevation Satellite(ICESat).The forest AGB prediction models were separately developed for different forest types in the research area at GLAS footprint level from GLAS waveform parameters and field survey plot biomass in the Changqing(CQ) Forest Center,which was calculated from forest inventory *** resulted statistical regression models have a R2=0.68 for conifer and R2=0.71 for broadleaf *** models were used to estimate biomass for all GLAS footprints of forest located in the study *** GLAS footprint biomass coupled with various spectral reflectivity parameters and vegetation indices derived from HJ-1 satellite CCD data were used in multiple regression analyses to establish biomass prediction models(R2=0.55 and R2=0.52 for needle and broadleaf respectively).Then the models were used to produce a forest AGB map for the whole study area using the HJ-1 *** data obtained from forest inventory data of the Zhuanglin(ZL) Forest Center were used as independent field measurements to validate the AGB estimated from HJ-1 CCD data(R2=0.71).About 80% of biomass samples had an error less than 20 t ha-1,and the mean error of all validation samples is 5.74 t *** pixel-level biomass map was then stratified into different biomass levels to illustrate the AGB spatial distribution pattern in this *** was found that HJ-1 wide-swath data and GLAS waveform data can be combined to estim

关键词： Disaster and Environment Monitoring and Forecast Satellite ICESat GLAS waveform boreal forest forest aboveground biomass multiple linear regression

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

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

An ID-based authenticated dynamic group key agreement with optimal round

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Science china(Information sciences) 2012年第11期55卷 2542-2554页

作者： TENG JiKai1,2,WU ChuanKun1 & TANG ChunMing3 1State Key Laboratory of Information Security,Institute of Software of chinese academy of sciences,beijing 100090,china 2graduate university of chinese academy of sciences,beijing 100049,china 3Faculty of Mathematic and Information Science,Guangzhou university,Guangzhou 510006,china State Key Laboratory of Information Security Institute of Software of Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China Faculty of Mathematic and Information Science Guangzhou University Guangzhou China

Group key agreement protocols are crucial for achieving secure group *** are designed to provide a set of users with a shared secret key to achieve cryptographic goal over a public *** group membership changes,the session key should be refreshed efficiently and *** previous group key agreement protocols need at least two rounds to establish or refresh session *** this paper,a dynamic authenticated group key agreement(DAGKA) protocol based on identity-based cryptography is *** making use of the members' values stored in previous sessions,our Join and Leave algorithms reduce the computation and communication costs of *** the proposed protocol,Setup and Join algorithms need one *** session key can be refreshed without message exchange among remaining users in Leave algorithm,which makes the protocol more *** security is proved under decisional bilinear Diffie-Hellman(DBDH) assumption in random oracle model.

关键词： identity-based cryptography dynamic group key agreement provably secure admissible pairing

Vortex genesis over the Bay of Bengal in spring and its role in the onset of the Asian Summer Monsoon

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Science china Earth sciences 2011年第1期54卷 1-9页

作者： WU GuoXiong1, GUAN Yue1,2, WANG TongMei3, LIU YiMin1, YAN JingHui4 & MAO JiangYu1 1 State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics (LASG), Institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, china 2graduate university of chinese academy of sciences, beijing 100049, china 3Department of Atmospheric Science, Sun Yat-Sen university, Guangzhou 510275, china 4National Climate Center, china Meteorological Administration, beijing 100080, china State Key Laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Department of Atmospheric Science Sun Yat-Sen University Guangzhou 510275 China National Climate Center China Meteorological Administration Beijing 100080 China

Physical processes associated with onset of the 1998 Asian summer monsoon were examined in detail using multi-source datasets. We demonstrated that strong ocean-atmosphere-land interaction in the northern Indian Ocean and tropical Asian area during spring is a fundamental factor that induces the genesis and development of a monsoon onset vortex over the Bay of Bengal (BOB), with the vortex in turn triggering onset of the Asian summer monsoon. In spring, strong surface sensible heating over India and the Indochina Peninsula is transferred to the atmosphere, forming prominent in situ cyclonic circulation, with anticyclonic circulations over the Arabian Sea and northern BOB where the ocean receives abundant solar radiation. The corresponding surface winds along the North Indian Ocean coastal areas cause the ocean to produce the in situ offshore currents and upwelling, resulting in sea surface temperature (SST) cooling. With precipitation on the Indochina Peninsula increasing from late April to early May, the offshore current disappears in the eastern BOB or develops into an onshore current, leading to SST increasing. A southwest-northeast oriented spring BOB warm pool with SST >31°C forms in a band from the southeastern Arabian Sea to the eastern BOB. In early May, the Somali cross-equatorial flow forms due to the meridional SST gradient between the two hemispheres, and surface sensible heat over the African land surface. The Somali flow overlaps in phase with the anticyclone over the northern Arabian Sea in the course of its inertial fluctuation along the equator. The convergent cold northerlies on the eastern side of the anticyclone cause the westerly in the inertial trough to increase rapidly, so that enhanced sensible heat is released from the sea surface into the atmosphere. The cyclonic vorticity forced by such sensible heating is superimposed on the inertial trough, leading to its further increase in vorticity strength. Since atmospheric inertial motion is destr

关键词： air-sea interaction spring BOB warm pool monsoon onset vortex inertial oscillation Asian summer monsoon onset

Studies on MB-SAR 3D imaging algorithm using Yule-Walker method

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Science china(Information sciences) 2010年第9期53卷 1848-1859页

作者： WANG Bin1,2*,WANG YanPing1,HONG Wen1,TAN WeiXian1,2 & WU YiRong1 1National Key Laboratory of Microwave Imaging Technology,Institute of Electronics,chinese academy of sciences,beijing 100190,china 2graduate university of chinese academy of sciences,beijing 100049,china National Key Laboratory of Microwave Imaging Technology Institute of Electronics Chinese Academy of Sciences graduate university of chinese academy of sciences

Multibaseline synthetic aperture radar(MB-SAR) can form a synthetic aperture in the height direction with multiple parallel observations,so it has the resolving capability in the height direction and can realize three-dimensional(3D) imaging for the *** analytic model of MB-SAR based on spectrum estimation is analyzed in this *** on the more general geometric model,we derive the signal model for MB-SAR 3D *** then Yule-Walker algorithm is proposed to realize MB-SAR 3D imaging meanwhile the principle is analyzed and the steps of Yule-Walker algorithm are *** algorithm can get the 3D image of the target with high resolution using fewer ***,the experimental results of MB-SAR 3D imaging using Yule-Walker algorithm are presented,which are generated with the simulated data and the data collected in anechoic chamber.

关键词： MB-SAR 3D SAR imaging algorithm SAR spectrum estimation Yule-Walker method

Properties of the 3/2^-[521] band in the odd-N rare-earth nuclei

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Science china(Physics,Mechanics & Astronomy) 2011年第S1期54卷 37-43页

作者： CHEN Liang1,2, ZHOU XiaoHong1,2, ZHANG YuHu1, ZHANG ShuangQuan3 & ZHU LiHua4 1Institute of Modern Physics, chinese academy of sciences, Lanzhou 730000, china 2graduate university of chinese academy of sciences, beijing 100049, china 3State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking university, beijing 100871, china 4china Institute of Atomic Energy, beijing 102413, china Institute of Modern Physics Chinese Academy of Sciences Lanzhou China graduate university of chinese academy of sciences Beijing China State Key Laboratory of Nuclear Physics and Technology School of Physics Peking University Beijing China china Institute of Atomic Energy Beijing China

High-spin states in 161Er have been studied experimentally via the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. Three rotational bands built on the 5/2+[642], 3/2-[521], and 11/2-[505] configurations have been extended up to high-spin states, and particularly, the α = -1/2 branch of the ground state 3/2-[521] band has been revised significantly. It is found that signature inversion occurs in the 3/2-[521] band after the band crossing in 161Er. The systematics of the signature inversion associated with the 3/2-[521] configuration in the rare-earth region is discussed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and a triaxial deformation is proposed to the 3/2-[521] band.

关键词： high-spin states signature inversion triaxial particle-rotor model

Hypocrellin B doped and pH-responsive silica nanoparticles for photodynamic therapy

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Science china Chemistry 2010年第9期53卷 1994-1999页

作者： LI ZhaoBo1,2,WANG JianGuang1,2,CHEN JingRong1,LEI WanHua1,WANG XueSong1 & ZHANG BaoWen1 1Key Laboratory of Photochemical Conversion and Optoelectronic Materials,Technical Institute of Physics and Chemistry,chinese academy of sciences,beijing 100190,china 2graduate university of chinese academy of sciences,beijing 100049,china Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing China graduate university of chinese academy of sciences Beijing China

pH-responsive 1O2 photosensitizing systems may serve as selective photodynamic therapy(PDT) agents by targeting the acidic interstitial fluid of many kinds of *** this work,a natural and clinically used photosensitizer(Hypocrellin B,HB) and a pH indicator(Bromocresol Purple,BCP) were co-encapsulated in organically modified silica *** successfully regulated the 1O2 generation efficiency of HB through the "inner filter" effect,which shows much stronger 1O2 generation ability in an acidic than in a basic *** vitro experiments also demonstrated that HB-doped nanoparticles are effective in killing tumor cells by PDT.

关键词： photodynamic therapy pH responsive bromocresol purple hypocrellin b silica nanoparticles

Effect of Nitrate on Root Development and Nitrogen Uptake of Suaeda physophora Under NaCl Salinity

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Pedosphere 2010年第4期20卷 536-544页

作者： YUAN Jun-Feng FENG Gu MA Hai-Yan TIAN Chang-Yan Key Laboratory of Oasis Ecology and Desert Environment Xinjiang Institute of Ecology and Geography ChineseAcademy of Sciences Urumqi 830011 （China） graduate-university of chinese academy of sciences Beijing 100039 （China） College of Resources and Environmental sciences China Agricultural University Beijing 100094 （China）

The effects of NaCl salinity and NO^-3 on growth, root morphology, and nitrogen uptake of a halophyte Suaeda physophora were evaluated in a factorial experiment with four concentrations of NaCl （1, 150, 300, and 450 mmol L^-1） and three NO^-3 levels （0.05, 5, and 10 mmol L^-1） in solution culture for 30 d. Addition of NO^-3 at 10 mmol L^-1 significantly improved the shoot （P 〈 0.001） and root （P 〈 0.001） growth and the promotive effect of NO^-3 was more pronounced on root dry weight despite the high NaCl concentration in the culture solution, leading to a significant increase in the root：shoot ratio （P 〈 0.01）. Lateral root length, but not primary root length, considerably increased with increasing NaCl salinity and NO^-3 levels （P 〈 0.001）, implying that Na^＋ and NO3^- in the culture solution simultaneously stimulated lateral root growth. Concentrations of Na^＋ in plant tissues were also significantly increased by higher NaCl treatments （P 〈 0.001）. At 10 mmol L^-1 NO^-3, the concentrations of NO^-3 and total nitrogen and nitrate reductase activities in the roots were remarkably reduced by increasing salinity （P 〈 0.001）, but were unaffected in the shoots. The results indicated that the fine lateral root development and effective nitrogen uptake of the shoots might contribute to high salt tolerance of S. physophora under adequate NO^-3 supply.

关键词： halophyte lateral roots nitrate reductase activity root morphology