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Highly Cis-1,4 Selective Polymerization of Conjugated Dienes Catalyzed by ^-heterocyclic Carbene-ligated Neodymium Complexes

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Chinese Journal of Polymer Science 2020年第12期38卷 1305-1312页

作者： Shu Zhang na wu Yi-Xian wu State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China

Neodymium complexes containing N heterocyclic carbene(NHC)ligands,NdCl5[1,3,R(NCH=)2C]-THF,(Nd1:R=2,6-Pr2C6H3,x=0;Nd2:R=2,6-Et2C6H3,x=1;Nd3:R=2.4,6-Me3C6H2,x=1)were synthesized and employed as precatalysts for the coordination polymerization of conjugated dienes(butadiene and isoprene).In combination with trisobutylaluminium(TIBA),Nd1 promoted butadiene polymerization to produce extremely high cis-1,4(up to 99.0%)polybutadienes with high molecular weight(Mw=250-780 kg·mol 1).The Nd1/TIBA catalytic system also exhibited both high catalytic activity and cis-1,4 selectivity(up to 97.8%)for isoprene *** catalytic activity,molecular weight and molecular weight distribution of resulting polydienes were directly influenced by Al/Nd molar ratio,aging method,and polymerization *** interestingly,the high cis-1,4 selectivity of the catalyst towards butadiene and isoprene kept almost unchanged under different reaction *** cis-1,4 polyisoprenes with high molecular weight(Mw=210-530 kg·mol 1)and narrow molecular weight distribution (Mw/Mn=1.9-2.7)as well as high cis-1.4 selectivity(-~97%)could be synthesized by using the aged Nd1/TIBA catalytic system in the presence of isoprene(100 equivalent to Nd)at low AlNd molar ratios of *** with low molecular weights(Mw=12-76 kg·mol-7)and narrow molecular weight distributions (Mw/Mn=1.7-2.6)were obtained by using Nd2 and Nd3 as precatalysts,indicating that the molecular weight of resulting polyisoprenes can be adjusted by changing the substitutes of ligand in Nd complex.

关键词： Neodymium complex N heterocydic carbene igand Coordination polymerization Cis-14 sletivity Aging method

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VARIABILITY SETS AND HAMILTON SEQUENCES

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Chinese Annals of Mathematics,Series B 2005年第4期26卷 543-550页

作者： SUN na wu SHENGJIAN Key Laboratory of Pure and Applied Mathematics School of Mathematical Sciences Peking University Beijing 100871 China.

This paper studies extremal quasiconformal mappings. Some properties of the variability set are obtained and the Hamilton sequences which are induced by point shift differentials are also discussed.

关键词： Quasiconformal mapping Point shift differentials Hamilton sequence Extremal mapping

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Dna nanostructures as Drug Carriers for Cellular Delivery

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Chemical Research in Chinese Universities 2020年第2期36卷 177-184页

作者： wu na ZHAO Yongxi Key Laboratory of Biomedical Information Engineering of Ministry of Education School of Life Science and TechnologyXi’an Jiaotong UniversityXi’an 710049P R.China

Drug delivery systems have been widely developed for enhancing target activity and improving drug ***,high-molecular polymer,gold nanoparticles and carbon nanomaterials,etc.,are all the candidates of drug ***,immunotoxicity,heterogeneity and low solubility generally exist and hamper their *** a kind of biological materials,Dna has its unique advantages in biomedical applications,including excellent biological compatibility and *** nanostructures have been proved to possess high cellular uptake efficiency,which sheds new light on Dna-based drug delivery *** this review,we summarize the influence factors of Dna nanostructure internalization efficiency,including cell lines,and the size and the shape of Dna *** of Dna nanostructures in appearance and properties ensures the stability in research,which makes Dna carriers stand out from other ***,we focus on the functionalization of Dna carriers,which endows Dna nanostructures with the potential to construct integrated drug delivery *** also discuss the internalization pathways of Dna nanostructures and their fate in *** deeply understanding about the endocytic pathways provides new sight for the further design strategy on changing the transportation routes of Dna carriers in ***,the challenges in further applications are discussed,and suggestions are proposed.

关键词： Dna nanostructure Drug delivery Cellular uptake Internalization pathway Dna-based drug carrier

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Structural dynamic responses of a stripped solar sail subjected to solar radiation pressure

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Chinese Journal of Aeronautics 2020年第8期33卷 2204-2211页

作者： Junhui ZHANG na wu An TONG Yinghua LIU School of Civil Engineering North China University of TechnologyBeijing 100144China School of Aerospace Engineering Tsinghua UniversityBeijing 100144China

The stripped solar sail whose membrane is divided into separate narrow membrane strips is believed to have the best structural *** this paper,the stripped solar sail structure is regarded as an assembly made by connecting a number of boom-strip components in *** the coupling effects between booms and membrane strips,an exact and semianalytical method to calculate structural dynamic responses of the stripped solar sail subjected to solar radiation pressure is *** case study of a 100 m stripped solar sail shows that the stripped architecture helps to reduce the static deflections and amplitudes of the steady-state dynamic *** prestress of the membrane strips will decrease stiffness of the sail and increase amplitudes of the steady-state dynamic *** thickness of the boom will benefit to stability of the sail and reduce the resonant *** proposed semi-analytical method provides an efficient analysis tool for structure design and attitude control of the stripped solar sail.

关键词： Distributed transfer function method Frequency response Solar radiation pressure Solar sail Structural dynamic response

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Real-time vehicle tracking for traffic monitoring systems

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High Technology Letters 2016年第3期22卷 248-255页

作者：胡硕 Zhang Xuguang wu na Key Laboratory of Industrial Computer Control Engineering of Hebei Province Institute of Electrical EngineeringYanshan University Key Laboratory of Measurement Technology & Instrumentation of Hebei Province Institute of Electrical EngineeringYanshan University

A real-time vehicle tracking method is proposed for trattlC monitoring system at roau mte^cc- tions, and the vehicle tracking module consists of an initialization stage and a tracking stage. Li- cense plate location based on edge density and color analysis is used to detect the license plate re- gion for tracking initialization. In the tracking stage, covariance matching is employed to track the license plate. Genetic algorithm is used to reduce the computational cost. Real-time image tracking of multi-lane vehicles is achieved. In the experiment, test videos are recorded in advance by record- ers of actual E-police systems erage false detection rate and at several different city intersections. In the tracking module, the av- missed plates rate are 1.19%, and 1.72%, respectively.

关键词： traffic monitoring system covariance matching genetic algorithms vehicle tracking

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Biopolymer-Based Aerogels for Electromagnetic Wave Shielding and Absorbing

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Chinese Journal of Chemistry 2023年第3期41卷 322-334页

作者： Mingrui Han Runa Zhang Qilei wu na wu Jiurong Liu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education and School of Materials Science and EngineeringShandong UniversityJinanShandong250061 China Science and Technology on Electromagnetic Compatibility Laboratory China Ship Development and Design CentreWuhanHubei430064 China Department of Chemistry and Applied Biosciences ETH ZurichCH-8093 ZurichSwitzerland

The rapid development of communication technology and electronic industry has brought unprecedented serious electromagnetic interference(EMI)and electromagnetic wave(EMW)*** EMI shields and EMW absorbers based on metal or magnetic materials were used to solve these problems,they have long been criticized for their high price,high density and easy *** order to achieve low density and efficient dissipation of electromagnetic energy,aerogels stand out among manifold ***,constructing aerogels with good EMI shielding or EMW absorption performance and acceptable mechanical properties is not an easy *** biopolymers,such as cellulose,lignin,chitin/chitosan and alginate,breathe new life into aerogels for high-efficiency EMW shielding and ***,we reviewed the contributions of biopolymers in the fields of aerogels for EMW shielding and *** the same time,some challenges and outlook were also pointed out,aiming to promote the advance of aerogel-based EMI shields and EMW absorbers as well as the rational utilization of biopolymers.

关键词： Polymers Sustainable chemistry Electromagnetic interference(EMI)shielding Electromagnetic wave(EMW)absorbing Biomass Aerogels Biopolymers

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Hydrogel-based composites beyond the porous architectures for electromagnetic interference shielding

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nano Research 2022年第10期15卷 9614-9630页

作者： Yunfei Yang Mingrui Han Wei Liu na wu Jiurong Liu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials School of Materials Science and EngineeringShandong UniversityJinan 250061China State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China Shenzhen research institute of Shandong University Shenzhen 518052China Department of Chemistry and Applied Biosciences ETH ZurichZurich CH-8093Switzerland

With the rapid development of the electronic industry and wireless communication technology,electromagnetic interference(EMI)or pollution has been increasingly *** not only severely endangers the normal operation of electronic equipment but also threatens human ***,it is urgent to develop high-performance EMI shielding *** advent of hydrogel-based materials has given EMI shields a novel *** combined with conductive functional materials have good mechanical flexibility,fatigue durability,and even high stretchability,which are beneficial for a wide range of applications,especially in EMI shielding and some flexible functional ***,the current progress of hydrogel-based EMI shields was reviewed,in the meanwhile,some novel studies about pore structure design that we believe will help advance the development of hydrogel-based EMI shielding materials were also *** the outlook,we suggested some promising development directions for the hydrogel-based EMI shields,by which we hope to provide a reference for designing hydrogels with excellent EMI shielding performance and multifunctionalities.

关键词： electromagnetic interference(EMI)shielding porous hydrogels structural design composites

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A hydrophobic artificial solid-interphase-protective layer with fast self-healable capability for stable lithium metal anodes

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Science China Chemistry 2022年第9期65卷 1817-1821页

作者： Lu Zhou Mengfan Zhao Xinyu Chen Jinming Zhou Mingxing wu na wu Key Laboratory of Inorganic nanomaterials of Hebei Province College of Chemistry and Material ScienceHebei Normal UniversityShijiazhuang 050024China

Lithium(Li)metal has been considered as one of the most promising anodes for high-energy-density ***,the hyperactivity of metallic Li and its dendrite growth are the major hurdles to its practical ***,a multi-functional solid-interphase-protective layer with excellent waterproof performance and fast self-healing properties was modified on the surface of Li metal to address the above *** the protection of this interface,the metallic Li(denoted as P-Li)exhibited superior electrochemical stability in both Li/Li symmetric cells and full ***,even after being exposed to humid air for 3 h,the LiFePO_(4)||Li full battery with P-Li anodes still showed long-term stability with a transcendental capacity retention of~100% after 100 cycles,revealing a significant advantage to the non-working LiFePO_(4)||Li battery with air-exposed bare Li anodes.

关键词： Li metal anode solid interphase protective layer stable Li plating/stripping self-healable hydrophobic property

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Effect of Deficit Irrigation on the Growth, Water Use Characteristics and Yield of Cotton in Arid Northwest China

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Pedosphere 2015年第6期25卷 910-924页

作者： YANG Chuanjie LUO Yi SUN Lin wu na Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences University of Chinese Academy of Sciences Farmland Irrigation Research Institute Chinese Academy of Agricultural Sciences

Water shortage is a key constraint to sustainable agricultural production in Xinjiang, Northwest China. To enhance the use efficiency of valuable irrigation water resources, a 2-year experiment(2010–2011) was conducted to quantify the response of cotton(Gossypium hirsutum L.) growth and yield to different degrees of deficit irrigation(DI) regimes; to determine the effects of DI on the characteristics of water use for cotton, seasonal water use, available soil water in the root zone, soil water depletion, evapotranspiration(ET)-based water use efficiency and irrigation-based water use efficiency, and to determine the best DI regime for optimal water-saving and yield output. The plots were irrigated at 100%(100ET), 85%(85ET), 70%(70ET), 55%(55ET) and 45%(45ET) of the regional ET of cotton in northern Xinjiang. The effect of DI irrigation on water use characteristics was evaluated by analyzing available soil water and soil water depletion in the root zone along with water use efficiencies of cotton. The study showed that the growth, water use characteristics and yield of cotton varied with irrigation regime. Seasonal ET and seed cotton yield were linearly correlated with irrigation amount. The second-order polynomial equation best approximated water-yield relationship of cotton in the study *** yield response factor was 0.65, suggesting limited water conditions were suitable for cotton cultivation. Economic evaluation of DI treatments confirmed that the yield loss was less than 10% under 70 ET and 85 ET, which was acceptable for greater *** results suggested that proper DI schemes were necessary for sustainable cotton production in the region. While irrigation at 85 ET was safe for high cotton yield, irrigation at 70 ET was a viable alternative under limited irrigation water availability.

关键词： available soil water evapotranspiration soil water dynamics water use efficiencies water-yield relationship

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Small G Rac1 is involved in replication cycle of dengue serotype 2 virus in EAhy926 cells via the regulation of actin cytoskeleton

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Science China(Life Sciences) 2016年第5期59卷 487-494页

作者： Jing Zhang na wu na Gao Wenli Yan Ziyang Sheng Dongying Fan Jing An Department of Microbiology School of Basic Medical Sciences Capital Medical University Beijing 100069 China Center of Epilepsy Beijing Institute for Brain Disorders Beijing 100069 China

Bleeding is a clinical characteristic of severe dengue and may be due to increased vascular permeability. However, the patho- genesis of severe dengue remains unclear. In this study, we showed that the Racl-microfilament signal pathway was involved in the process of DENV serotype 2 （DENV2） infection in EAhy926 cells. DENV2 infection induced dynamic changes in actin organization, and treatment with Cytochalasin D or Jasplakinolide disrupted microfilament dynamics, reduced DENV2 entry, and inhibited DENV2 assembly and maturation. Racl activities decreased during the early phase and gradually increased by the late phase of infection. Expression of the dominant-negative form of Racl promoted DENV2 entry but inhibited viral as- sembly, maturation and release. Our findings demonstrated that Racl plays an important role in the DENV2 life cycle by reg- ulating actin reorganization in EAhy926 cells. This finding provides further insight into the pathogenesis of severe dengue.

关键词： dengue virus small Rho GTPase Racl actin vascular endothelial cells

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