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A New Flavonoid Ketohexofuranoside from Leaves of Crataegus pinnatifida ***. major ***.

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Chinese Chemical Letters 2000年第10期11卷 895-896页

作者： pei Cheng ZHANG Sui xu xu Institute of Materia Medica Chinese Academy of Medical Science and Peking Union Medical CollegeBeijing 100050 Department of Phytochemistry Shenyang Pharmaceutical UniversityShenyang 110015

A new flavonoid, namely pinnatifine I (1), was isolated from the leaves of Crataegus pinnatifida Bge. var. major ***.. Its structure was elucidated by spectroscopic analysis and chemical evidence.

关键词： Crataegus pinnatifida Bge.var.major NEBr. Rosaceae pinnatifine I flavonoid Ketohexofuranoside

The simple synthesis of quinazoline-2,4-dione derivatives using Boc strategy

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Chinese Chemical Letters 2009年第10期20卷 1201-1203页

作者： xu qin Li School of Applied Science University of Science and Technology Beijing Beijing 100083 China

Quinazolinediones are particularly attractivc pharrnacophores because of theix wide range of bioactivities. A convenient synthetic pathway to three-substituted quinazolinc-2,4-dionc derivatives was developed from substituted anthranilamide via carbonylation with Boc anhydride and then cyclization in the presence of the base sodium mcthoxidc. Good to cxceUcnt yields have bccn achieved.

关键词： Quinazolinediones Carbonylation Cyclization Boc strategy

The Number of Rooted Circuit Boundary Maps

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Acta Mathematica Sinica,English Series 2010年第9期26卷 1653-1666页

作者： Yan xu Yan pei LIU School of Science Tianjin Polytechnic University Tianjin 300160 P. R. China Department of Mathematics Beijing Jiaotong University Beijing 100044 P. R. China

In this article, the authors discuss two kinds of new planar maps： pan-fan maps and circuit boundary maps, and provide explicit expressions about their enumerating functions with different parameters. Meanwhile, two explicit counting formulas for circuit cubic boundary maps with two parameters; the size and the valency of the root-face, are also extracted.

关键词： Rooted map enumerating function enumeration circuit boundary maps

Harmonic Amplification Analysis of Cable Lines with Distributed Parameters Based on Kalman Filter and Convolution Inversion

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Journal of Modern Power Systems and Clean Energy 2023年第6期11卷 1804-1813页

作者： Yang Pu qin Shu Fangwei xu College of Electrical Engineering Sichuan UniversityChengdu 610065China IEEE

Harmonic amplification phenomena could appear at the point of common connection(PCC) of the cable line terminal. However, the distributed parameter model of the cable line contains hyperbolic functions with plural variables, which makes it challenging to obtain the harmonic amplification factor(HAF). Hence, a time-domain method combining the Kalman filter and convolution inversion(KFCI) methods is proposed to address this problem. First, the Kalman filter method optimizes the square wave pulse response(SWPR) with measurement error. Then, the optimized SWPR data are used to get the HAF by the convolution inversion method. Next, the harmonic amplification characteristics of cable lines are explored. Finally, an experimental simulation model is built on the PSCAD software, verifying the optimization effectiveness of Kalman filter for the SWPR with error and the accuracy of the HAF calculated by the proposed method. The analysis rationality of harmonic amplification properties is also demonstrated.

关键词： Cable line distributed parameter Kalman filter convolution inversion harmonic amplification

A Census of Petal Bundles by Genus

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Acta Mathematica Sinica,English Series 2008年第6期24卷 937-946页

作者： Yan xu Yan pei LIU School of Science Tianjin Polytechnic University Tianjin 300160 P. R. China Department of Mathematics Beijing Jiaotong University Beijing 100044 P. R. China

This paper provides the uniform enumerative functional equation of orientable （nonori-entable） rooted petal bundles with more parameters, and deduces two recursion formulas for calculation. Accordingly, an explicit ... 详细信息

关键词： rooted map enumerating function enumeration petal bundles

Visualization and analysis of local and distant population flows on the qinghai-Tibet Plateau using crowd-sourced data

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Journal of Geographical Sciences 2021年第2期31卷 231-244页

作者： xu Jun LIU Ju xu Yang pei Tao State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China

Human migration between cities is one important aspect of spatial interaction that not only reflects urban attractiveness but also denotes interactions amongst *** therefore implemented a web-based visualization system to analyze and interactively explore local and distant population flow patterns between cities on the qinghai-Tibet Plateau(QTP).We utilized 2017 Tencent population flow data from which we initially constructed inbound and outbound vectors for cities on the *** then used multidimensional scaling to examine and visualize migration patterns and similarities between *** reveal the presence of six local and three distant human mobility patterns on the QTP as well as average summer monthly migrations more than twice the level of those in the winter.

关键词： population flow visualization Tencent location big data spatiotemporal pattern qinghai-Tibet Plateau

Computing Streamfunction and Velocity Potential in a Limited Domain of Arbitrary *** I:Theory and Integral Formulae

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Advances in Atmospheric Sciences 2011年第6期28卷 1433-1444页

作者： qin xu 高守亭曹洁 NOAA/National Severe Storms Laboratory Norman Oklahoma USA Cooperative Institute for Mesoscale Meteorological Studies University of Oklahoma USA Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 （Received 15 October 2010 revised 9 March 2011）

The non-uniqueness of solution and compatibility between the coupled boundary conditions in computing velocity potential and streamfunction from horizontal velocity in a limited domain of arbitrary shape are revisited theoretically with rigorous mathematic *** integral formulas and their variants are used to formulate solutions for the coupled *** the absence of data holes,the total solution is the sum of two integral *** is the internally induced solution produced purely and uniquely by the domain internal divergence and vorticity,and its two components（velocity potential and streamfunction） can be constructed by applying Green＇s function for Poisson equation in unbounded domain to the divergence and vorticity inside the *** other is the externally induced solution produced purely but non-uniquely by the domain external divergence and vorticity,and the non-uniqueness is caused by the harmonic nature of the solution and the unknown divergence and vorticity distributions outside the *** setting either the velocity potential（or streamfunction） component to zero,the other component of the externally induced solution can be expressed by the imaginary（or real） part of the Cauchy integral constructed using the coupled boundary conditions and solvability conditions that exclude the internally induced *** streamfunction（or velocity potential） for the externally induced solution can also be expressed by the boundary integral of a double-layer（or singlelayer） density *** the presence of data holes,the total solution includes a data-hole-induced solution in addition to the above internally and externally induced solutions.

关键词： integral formulae streamfunction velocity potential domain of arbitrary shape

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Development and characterization of monoclonal antibodies against human aryl hydrocarbon receptor

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Journal of Environmental Sciences 2016年第1期28卷 165-174页

作者： Wenjing Tian Xinhui pei Heidi Qunhui Xie Sherry Li xu Jijing Tian qin Hu Haiming xu Yangsheng Chen Hualing Fu Zhengyu Cao Bin Zhao Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing I00085 China China Pharmaceutical University Nanjing 211198 China

Aryl hydrocarbon receptor（Ah R）, a ligand-dependent nuclear receptor, is involved in a diverse spectrum of biological and toxicological effects. Due to the lack of three dimensional（3D）crystal or nuclear magnetic resonance structure, the mechanisms of these complex effects of AhR remain to be unclear. Also, commercial monoclonal antibodies（mA bs） against human AhR protein（h Ah R）, as alternative immunological tools, are very limited. Thus, in order to provide more tools for further studies on h Ah R, we prepared two m Abs（1D6 and 4A6） against h Ah R. The two newly generated m Abs specifically bound to amino acids 484–508（located in transcription activation domain） and amino acids 201–215（located in Per-ARNT-Sim domain）of h Ah R, respectively. These epitopes were new as compared with those of commercial m *** m Abs were also characterized by enzyme-linked immunosorbent assay, western blot,immunoprecipitation and indirect immunofluorescence assay in different cell lines. The results showed that the two m Abs could recognize the linearized AhR s in six different human cell lines and a rat hepatoma cell line, as well as the h Ah R with native conformations. We concluded that the newly generated m Abs could be employed in AhR-based bioassays for analysis of environmental contaminants, and held great potential for further revealing the spatial structure of AhR and its biological functions in future studies.

关键词： Aryl hydrocarbon receptor Monoclonal antibody Western blot Immunoprecipitation Indirect immunofluorescence assay

A novel shape memory alloy actuated soft gripper imitated hand behavior

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Frontiers of Mechanical Engineering 2022年第4期17卷 261-272页

作者： Jie PAN Jingjun YU xu pei School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China

The limited length shrinkage of shape memory alloy(SMA)wire seriously limits the motion range of SMA-based *** this paper,a new soft finger without silicone gel was designed based on pre bent SMA wire,and the finger was back to its original shape by heating SMA wire,rather than relying only on heat exchange with the *** imitating palm movement,a structure with adjustable spacing between fingers was made using SMA spring and rigid *** hook structure design at the fingertip can form self-locking to further improve the load capacity of *** the long thin rod model,the relationship of the initial pre bent angle on the bending angle and output force of the finger was *** stress-strain model of SMA spring was established for the selection of rigid *** grasping modes were proposed to adapt to the weight of the *** the test of the gripper,it was proved that the gripper had large bending amplitude,bending force,and response *** design provides a new idea for the lightweight design and convenient design of soft gripper based on SMA.

关键词： shape memory alloy(SMA) pre bent wire gripper grasping mode lightweight