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Boundary Regularity of Isometries Between Infinitely Flat Complex Domains

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1375-1387页

作者： Jin song LIU Fei tao Hong Yu wang Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190P.R.China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049P.R.China Beijing International Center for Mathematical Research Peking UniversityBeijing 100871P.R.China School of Science Beijing University of Posts and TelecommunicationsBeijing 100876P.R.China Key Laboratory of Mathematics and Information Networks(Beijing University of Posts and Telecommunications) Ministry of EducationBeijing 100876P.R.China

In this paper we prove that isometries with respect to the Kobayashi metric between certain domains having boundary points at which the boundary is infinitely flat extend continuously to the *** strategy is to reestab... 详细信息

关键词： Boundary extension Kobayashi metric isometries

Multi-locomotion transition of tensegrity mobile robot under different terrains

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Science China(Technological Sciences) 2024年第2期67卷 536-557页

作者： YANG Qi LIU XinYu wang PanFeng song YiMin SUN tao Key Laboratory of Mechanism Theory and Equipment Design(Tianjin University) Ministry of EducationTianjin UniversityTianjin 300350China

Knowing how to make a multi-locomotion robot achieve locomotion transition under different terrains is a challenging problem,especially for tensegrity robots with multi-locomotion *** this study,a motion planning method for the transition of a multi-locomotion tensegrity robot(hereafter TJUBot)under different terrains is *** robot can achieve four locomotion modes:earthworm-like,inchworm-like,tumbling,and sliding locomotion with only two *** models of the four locomotion modes under five typical terrains,including flat ground,confined space,obstacle,gap,and descending slope,are established using the energy ***,the kinematic characteristics(driving law and initial position)of the robot under these terrains are *** this basis,motion planning for the locomotion transition of TJUBot is conducted,which includes a perception strategy based on three laser sensors and a transition strategy under different *** driving laws of the two motors that can ensure the effective locomotion transition of TJUBot under different terrains are naturally ***,experiments are *** demonstrate that the robot can achieve effective locomotion transition when the motion planning method is used.

关键词： multi-locomotion robot tensegrity kinematic modeling locomotion transition

S-scheme regulated Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S hetero-homojunctions for efficient photocatalytic H_(2)evolution

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Journal of Materials Science & Technology 2024年第2期169卷 148-157页

作者： Qiqi Zhang Zhen wang Yuhang song Jun Fan tao Sun Enzhou Liu School of Chemical Engineering/Xi’an Key Laboratory of Special Energy Materials Northwest UniversityXi’an 710069China

Effective bulk phase and surface charge separation is critical for charge utilization during the photo-catalytic energy conversion *** this work,the ternary Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S(T-MCS)nanohybrids were successfully constructed via combining Ni_(2)P-NiS with T-MCS solid solution for visible light photocatalytic H_(2)evolution.T-MCS is composed of zinc blende Mn_(0.5)Cd_(0.5)S(ZB-MCS)and wurtzite Mn_(0.5)Cd_(0.5)S(WZ-MCS)and those two alternatively arranged crystal phases endow T-MCS with excellent bulk phase charge separation performance for the slight energy level difference between ZB-MCS and WZ-MCS.S-scheme carriers transfer route between NiS and T-MCS can accelerate the interfacial charge separation and retain the active electrons and holes,meanwhile,co-catalyst Ni_(2)P as electron receiver and proton reduction center can further optimize the H_(2)evolution reaction kinetics based on the surface Schottky barrier *** above-formed homo-heterojunctions can establish multiple charge transfer channels in the bulk phase of T-MCS and interface of T-MCS and Ni_(2)*** the synergistic effect of twinned homojunction,S-scheme heterojunction,and Schottky barrier,the ternary Ni_(2)P-NiS/T-MCS com-posite manifested an H_(2)production rate of 122.5 mmol h^(-1)g^(-1),which was 1.33,1.24,and 2.58 times higher than those of the NiS/T-MCS(92.4 mmol h^(-1)g^(-1)),Ni_(2)P/T-MCS(98.4 mmol h^(-1)g^(-1)),and T-MCS(47.5 mmol h^(-1)g^(-1)),*** work demonstrates a promising strategy to develop efficient sul-fides photocatalyst toward targeted solar-driven H_(2)evolution through homo-heterojunction engineering.

关键词： Photocatalytic H_(2)evolution Twinned Mn_(0.5)Cd_(0.5)S Homojunction S-scheme heterojunction Schottky barrier

Preparation and characterization of Rb-doped TiO_(2) powders for photocatalytic applications

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Rare Metals 2024年第2期43卷 555-561页

作者： Lu Jia Li-Mei Yang Wei wang song-tao Huang Zheng Xu National Engineering Laboratory of Biohydrometallurgy General Research Institute for Nonferrous MetalsBeijing100088China

TiO_(2)nanoparticles doped with different concentrations of Rb were prepared by sol–gel *** crystal structures of samples were characterized by X-ray diffraction(XRD)and transmission electron microscopy(TEM).It was confirmed by the Rietveld refinement method that the as-prepared samples crystallize in anatase phase and Rb doping induces expansion and distortion of the crystal *** with the pure TiO_(2),the Rb-doped nanoparticles have smaller crystal size and better *** rate of methylene blue was used to evaluate the photocatalytic activity of Rb–TiO_(2).It indicated that doping Rb into TiO_(2)can effectively improve the photocatalytic activity of TiO_(2)and the mechanisms were discussed in *** using the sample doped with 0.20%Rb,methylene blue degraded with the fastest rate(97%within 60 min).

关键词： Rb doping TiO_(2) Photocatalysis Sol-gel

Heuristic Expanding Disconnected Graph:A Rapid Path Planning Method for Mobile Robots

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 68-82页

作者： Yong tao Lian Duan He Gao Yufan Zhang Yian song Tianmiao wang School of Mechanical Engineering&Automation Beihang UniversityBeijing 100191China Aero-Engine Research Institute Beihang UniversityBeijing 102206China School of Large Aircraft Engineering Beihang UniversityBeijing 100191China

Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational *** to the limitations of the neighborhood search strategy,the robots could hardly obtain the most optimal global path.A global path planning algorithm,denoted as EDG*,is proposed by expanding nodes using a well-designed expanding disconnected graph operator(EDG)in this ***,all obstacles are marked and their corners are located through the map ***,the EDG operator is designed to find points in non-obstruction areas to complete the rapid expansion of disconnected ***,the EDG*heuristic iterative algorithm is *** selects the candidate node through a specific valuation function and realizes the node expansion while avoiding collision with a minimum *** planning experiments were conducted in a typical indoor environment and on the public dataset *** result shows that the proposed EDG*reduced the planning time by more than 90%and total length of paths reduced by more than 4.6%.Compared to A*,Dijkstra and JPS,EDG*does not show an exponential explosion effect in map *** EDG*showed better performance in terms of path smoothness,and collision *** shows that the EDG*algorithm proposed in this paper can improve the efficiency of path planning and enhance path quality.

关键词： Global path planning Mobile robot Expanding disconnected graph Edge node Offset

Multispectral point cloud superpoint segmentation

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Science China(Technological Sciences) 2024年第4期67卷 1270-1281页

作者： wang Qingwang wang MingYe ZHANG ZiFeng song Jian ZENG Kai SHEN tao GU YanFeng Faculty of Information Engineering and Automation Kunming University of Science and TechnologyKunming 650500China Yunnan Key Laboratory of Computer Technologies Application Kunming 650500China School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China

The multitude of airborne point clouds limits the point cloud processing *** are grouped based on similar points,which can effectively alleviate the demand for computing resources and improve processing ***,existing superpoint segmentation methods focus only on local geometric structures,resulting in inconsistent spectral features of points within a *** feature inconsistencies degrade the performance of subsequent ***,this study proposes a novel Superpoint Segmentation method that jointly utilizes spatial Geometric and Spectral Information for multispectral point cloud superpoint segmentation(GSI-SS).Specifically,a similarity metric that combines spatial geometry and spectral information is proposed to facilitate the consistency of geometric structures and object attributes within segmented *** the formation of the primary superpoints,an intersuperpoint pointexchange mechanism that maximizes feature consistency within the final superpoints is *** are conducted on two real multispectral point cloud datasets,and the proposed method achieved higher recall,precision,F score,and lower global consistency and feature classification *** experimental results demonstrate the superiority of the proposed GSI-SS over several state-of-the-art methods.

关键词： multispectral point cloud superpoint segmentation over-segmentation spatial-spectral joint metric

Feature extraction and learning approaches for cancellable biometrics:A survey

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CAAI Transactions on Intelligence Technology 2024年第1期9卷 4-25页

作者： Wencheng Yang song wang Jiankun Hu Xiaohui tao Yan Li School of Mathematics Physics and ComputingUniversity of Southern QueenslandToowoombaQueenslandAustralia School of Computing Engineering and Mathematical SciencesLa Trobe UniversityMelbourneVictoriaAustralia School of Engineering and Information Technology University of New South Wales at the Australian Defence Force Academy(UNSW@ADFA)CanberraAustralian Capital TerritoryAustralia

Biometric recognition is a widely used technology for user *** the application of this technology,biometric security and recognition accuracy are two important issues that should be *** terms of biometric security,cancellable biometrics is an effective technique for protecting biometric *** recognition accuracy,feature representation plays a significant role in the performance and reliability of cancellable biometric *** to design good feature representations for cancellable biometrics is a challenging topic that has attracted a great deal of attention from the computer vision community,especially from researchers of cancellable *** extraction and learning in cancellable biometrics is to find suitable feature representations with a view to achieving satisfactory recognition performance,while the privacy of biometric data is *** survey informs the progress,trend and challenges of feature extraction and learning for cancellable biometrics,thus shedding light on the latest developments and future research of this area.

关键词： biometrics feature extraction

Chemical vapor deposition for perovskite solar cells and modules

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Journal of Semiconductors 2024年第4期45卷 1-4页

作者： Zhihao tao Yuxuan song Baochang wang Guoqing Tong Liming Ding School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Metal halide perovskites are promising materials for solar cells because of high power conversion efficiency(PCE),tun-able bandgap,high defect tolerance,long carrier diffusion length,and low-cost fabrication[1-7].The PCE for perovskite solar cells(PSCs)reaches 26.14%for single-junction cells,29.1%for perovskite/perovskite tandem cells and 33.9%for perovskite/silicon tandem cells,being comparable to that for silicon and other thin-film solar cells[8-10].Perovskite solar cells have been made by solution methods including spin-coat-ing,blade coating and printing[11,12].

关键词： perovskite blade film

Variability and reduction of atmospheric pollutants in Beijing and its surrounding area during the Beijing 2008 Olympic Games

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Chinese Science Bulletin 2010年第18期55卷 1937-1944页

作者： XIN JinYuan wang YueSi TANG GuiQian wang LiLi SUN Yang wang YingHong HU Bo song tao JI DongSheng wang WeiFeng LI Liang LIU GuangRen State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy ofSciences Beijing 100029 China

The Beijing-Tianjin-Hebei Atmospheric Environment Monitoring Network was established by the Institute of Atmospheric Physics,Chinese Academy of *** goals of the network were to monitor and provide warnings of the atmospheric quality in Beijing and its surrounding area during the Beijing 2008 Olympic *** results showed that the atmospheric complex pollution exhibited high concentrations of ozone and fine particles and oxidation in summer,with a ubiquitous regional *** regional mean concentrations of SO2,PM2.5,NO2,and O3_8h max(the maximum daily 8 h mean) and Ox were 22±11,90±40,25±5,136±35 and 112±21 μg/m3 in summer,*** the Olympic Games,the mean concentration of SO2,PM2.5,NO2,O3_8h max,and Ox were 12.5±4,56±28,23±4,114±29,95±17 μg/m3 in the region,respectively,and fell by 51.0%,43.7%,13%,20.2%,and 18.9%,respectively,compared to the prophase mean before the Olympic *** concentration of atmospheric pollutants declined significantly and achieved the "Green Olympics" control goal of air *** the Olympic Games,SO2,PM2.5 and NOx increased significantly as the temporary atmospheric pollution control measures were terminated.

关键词：北京2008年奥运会大气污染物周边地区 2008年北京奥运会环境监测网络 PM2.5 平均浓度二氧化硫