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Atropoenantioselective synthesis of heterobiaryl N-oxides via dynamic kinetic resolution

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Science China Chemistry 2022年第12期65卷 2512-2516页

作者： xi Yuan jian Wang College of Chemistry and Materials Science Anhui Normal UniversityWuhu241002China School of Pharmaceutical Sciences Tsinghua UniversityBeijing100084China

A highly efficient enantioselective construction of heterobiaryl N-oxides was developed.A series of axially chiral heterobiaryl N-oxides were generated via the cascade reaction of aminobenzamides with heterobiaryl aldehydes in the presence of chiral phosphoric acids.A number of atropisomers were afforded in moderate to good yields with excellent enantioselectivities and *** results demonstrate that the heterobiaryl N-oxides can be utilized as efficient chiral ligands in asymmetric catalysis.

关键词： heterobiaryl N-oxides dynamic kinetic resolution chiral phosphoric acids atroposelectivity organocatalysis

Enhancement effect of cumulative second-harmonic generation by closed propagation feature of circumferential guided waves

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Chinese Physics B 2020年第2期29卷 301-308页

作者： Guang-jian gao Ming-xi Deng Ning Hu Yan-Xun xiang Department of Physics Army Logistics UniversityChongqing 401331China College of Aerospace Engineering Chongqing UniversityChongqing 400044China School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China

On the basis of second-order perturbation approximate and modal expansion approach,we investigate the enhancement effect of cumulative second-harmonic generation(SHG)of circumferential guided waves(CGWs)in a circular tube,which is inherently induced by the closed propagation feature of *** appropriate mode pair of primary-and double-frequency CGWs satisfying the phase velocity matching and nonzero energy flux is selected to ensure that the second harmonic generated by primary CGW propagation can accumulate along the *** a coherent superposition of multi-waves,a model of unidirectional CGW propagation is established for analyzing the enhancement effect of cumulative SHG of primary CGW mode *** theoretical analyses and numerical simulations performed directly demonstrate that the second harmonic generated does have a cumulative effect along the circumferential direction and the closed propagation feature of CGWs does enhance the magnitude of cumulative second harmonic *** applications of the enhancement effect of cumulative SHG of CGWs are considered and *** theoretical analysis and numerical simulation perspective presented here yield an insight previously unavailable into the physical mechanism of the enhancement effect of cumulative SHG by closed propagation feature of CGWs in a circular tube.

关键词： circumferential guided wave second-harmonic generation(SHG) enhancement effect of cumulative SHG closed propagation feature

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基于出租车上下客点的城市人口流动分析

测绘与空间地理信息 2016年第7期39卷 31-33页

作者：相恒茂姜伟高浠舰杨浚王艳东山东省国土测绘院山东济南250102 武汉大学测绘遥感信息工程国家重点实验室湖北武汉430079

掌握城市人口流动动态有利于进行交通预测、应急快速响应,以及合理的城市规划。出租车作为城市主要的交通运输工具之一,可以反映城市中人口的流动。本文以出租车上下客点数据为例,对比在工作日以及休息日的人口流动差异,分析出租车数据... 详细信息

掌握城市人口流动动态有利于进行交通预测、应急快速响应,以及合理的城市规划。出租车作为城市主要的交通运输工具之一,可以反映城市中人口的流动。本文以出租车上下客点数据为例,对比在工作日以及休息日的人口流动差异,分析出租车数据的空间分布及其动态变化,揭示城市人口流动模式。

关键词：出租车上下客点人口流动

Control of Heterometallic Three-Dimensional Macrocycles with Aromatic Stacks in Tunable Host Cavities

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Chinese Journal of Chemistry 2018年第7期36卷 594-598页

作者： Wen-xi gao Qi-Jia Fan Yue-jian Lin Guo-xin Jin Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials State Key Laboratory of Molecular Engineering of Polymers Collaborative Innovation Center of Chemistry for Energy Materials Department of ChemistryFudan University Shanghai 200433 China

Using coinage metal （Cu（Ⅱ）, Ag（Ⅰ）） hinges, two sets of heterometallic molecular capsules with analogous open-ended cavities were prepared based on the half-sandwich rhodium fragments. In the case of [Rh4Cu4] cages, up to six-fold-stacked host-guest structures were formed by varying the cavity＇s dimensions. Moreover, the series of capsules were demonstrated to self-fine-tune to form multi-heteroguest arrays via favourable donor-acceptor interactions and Ag-π interactions, as evidenced from single-crystal X-ray analysis.

关键词： host-guest chemistry open-ended cavity heterometallic capsule half-sandwich rhodium fragments

A New Disaccharide from the Fern Macrothelypteris digophlebia

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Chinese Chemical Letters 2000年第12期11卷 1063-1064页

作者： Ming Hua QIU Jin Ming gao Hu Qi LIU jian xi FU Kunming Institute of Botany The Chinese Academy of SciencesKunming 650204 Northwest Sci.&Tech.University of Agriculture and Forestry YanglingShaanxi 712100

A new disaccharide, digobiose 1, was isolated from the rhizomes of Macrothelypteris digophlebia (Bak.) Ching var. elegans (koidz.). Its structure which is very similar with that of sucrose was identified as alpha -D-g... 详细信息

关键词： Digobiose Disaccharide Macrothelypteris digophlebia

Study on Robust H_∞ Filtering in Networked Environments

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International Journal of Automation and computing 2011年第4期8卷 465-471页

作者： Yun-Ze Cai Li Xu jian-xi gao xiao-Ming Xu Department of Automation Shanghai Jiao Tong University Shanghai 200240 PRC Shanghai Academy of Systems Science Shanghai 200093 PRC Department of Electronics and Information Systems Akita Prefectural University Yuri-Honjo Akita 015 0055 Japan University of Shanghai for Science and Technology Shanghai 200093 PRC

This paper is concerned with the robust H ∞ filter problem for networked environments, which are subject to both transmission delay and packet dropouts randomly. By employing random series which have Bernoulli distributions taking value of 0 or 1, the data transmission model is obtained. Based on state augmentation and stochastic theory, the sufficient condition for robust stability with H ∞ constraints is derived for the filtering error system. The robust filter is designed in terms of feasibility of one certain linear matrix inequality （LMI）, which is formed by adopting matrix congruence transformations. A numerical example is given to show the effectiveness of the proposed filtering method.

关键词： Robust filtering networked environments transmission delay packet dropouts linear matrix inequality (LMI).

Alternating deposition films of a polymer and dendrimers bearing diphenylanthracene

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Chinese Science Bulletin 2005年第3期50卷 208-212页

作者： SUN Jing WANG Liyan gao jian YU xi WANG Zhiqiang Key Laboratory of Supramolecular Structure and Materials Jilin University Changchun 130012 China Key Laboratory of Organic Optoelectronics and Molecular Engineering Tsinghua University Bejjng 100084. China

Two generations of carboxyl-terminated poly (aryl ether) dendrimers bearing 9,10-diphenylanthracene cores are designed and synthesized. Alternating deposition of two dendrimers and poly(4-vinylpyridine) is studied with UV-Vis spectroscopy, FT-IR spectroscopy and atomic force microscopy. Experimental results indicate that this method to introduce chromophore into multilayer film can effectively prevent desorption of dye molecule. Moreover, it is found that dendrimer can inhibit the aggregation of fluorophore in film using fluorescence spectroscopy. Increase of dendrimer’s generation can enhance fluorescence intensity of each fluorophore. This provides a new approach to design lumi- nescent thin film.

关键词：交互沉积薄膜聚合物联苯蒽模树石化学结构

Recent Advances on Surface-modified Biomaterials Promoting Selective Adhesion and Directional Migration of Cells

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Chinese Journal of Polymer Science 2021年第7期39卷 815-823页

作者： Chen-xi Tu Chang-You gao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

The surfaces and interfaces of biomaterials interact with the biological systems in multi-scale levels,and thereby influence the biological functions and comprehensive performance in vitro and in *** particular,a surface promoting the selective adhesion and directional migration of desired types of cells in complex environment is extremely important in the repair and regeneration of tissues such as peripheral nerve and blood vessel,and long-term application of intracorporal devices such as intravascular ***,surface modification of biomaterials is a facile and effective method to achieve the desired cell-biomaterials *** this short review,recent advances on the surface modification of biomaterials to regulate selective cell adhesion and migration are briefly *** particular,the surface properties of biomaterials are manipulated via the convenient introduction of amino groups to the ester-based polymers,the formation of polyelectrolyte multilayers,and the fabrication of topology and gradient cues,etc.,followed by the association of chemical and biological signals such as collagen,heparin,hyaluronic acid,peptides and cell growth *** selective adhesion and directional migration of various types of cells such as endothelial cells(ECs),smooth muscle cells(SMCs),hepatocytes and Schwann cells(SCs)are achieved over the competitive counterpart cells by the use of cell-resisting substances and cell-selective motifs on gradient substrates in most *** advances on cell behaviors in three-dimensional(3D)ceH-extracellular matrix(ECM)-mimicking substrates are also reviewed.

关键词： Biomaterials Surface modification Gradient Cell migration Cell selectivity

Tuning coordination environment of iron ions to ensure ultra-high pseudocapacitive capability in iron oxide

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Nano Research 2023年第5期16卷 6914-6921页

作者： Wubin Du Chenhui Yan Mingxi gao jian Chen Panyu gao Xuebin Yu Yinzhu jiang Wenping Sun Yongfeng Liu Mingxia gao Shibo xi Hongge Pan State Key Laboratory of Silicon Materials and School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Institute of Science and Technology for New Energy Xi'an Technological UniversityXi'an 710021China Department of Materials Science Fudan UniversityShanghai 200433China Institute of Chemical and Engineering Sciences Agency for ScienceTechnology and ResearchSingapore 138632Singapore

The mechanism governing the pseudocapacitive lithium storage behavior is one of the most critical unsolved issues in conversion-type anodes for lithium-ion *** this work,we,for the first time,demonstrate that the pseudocapacitive capability of iron oxide-based anodes is closely associated with the electronic structures of iron *** proof of concept,the introduction of amorphization,nitrogen doping,oxygen vacancies reduces the coordination of iron ions and contributes significantly to the pseudocapacitive lithium storage capability of iron oxide,reaching up to 96%of the specific capacity at 1 mV·s^(−1).Due to the significantly modulated coordination environment,the 3d electrons of Fe(II)are delocalized with increased spin state and the energy band gap is narrowed,accompanied by an upshift of Fermi *** redox activity and carrier mobility of iron oxides are substantially increased,which substantially enhance the exchange current density and thereby improve the pseudocapacitive capability of iron oxide.

关键词： coordination environment electronic structure exchange current density pseudocapacitive capability lithium-ion batteries