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Current patterns of plant diversity and phylogenetic structure on the Kunlun Mountains

Plant Diversity 2022年第1期44卷 30-38页

作者： Wei-bo du Peng Jia Guo-Zhen du State Key Laboratory of Grassland and Agro-Ecosystems School of Life SciencesLanzhou UniversityLanzhouGansu Province730000P.R.China

Large-scale patterns of biodiversity and the underlying mechanisms that regulate these patterns are central topics in biogeography and *** Qinghai-Tibet Plateau serves as a natural laboratory for studying these ***,most previous studies have focused on the entire Qinghai-Tibet Plateau,leaving independent physical geographic subunits in the region less well *** studied the current plant diversity of the Kunlun Mountains,an independent physical geographic subunit located in northwestern China on the northern edge of the Qinghai-Tibet *** integrated measures of species distribution,geological history,and phylogeography,and analyzed the taxonomic richness,phylogenetic diversity,and community phylogenetic structure of the current plant diversity in the *** distribution patterns of 1911 seed plants showed that species were distributed mainly in the eastern regions of the Kunlun *** taxonomic richness,phylogenetic diversity,and genera richness showed that the eastern regions of the Kunlun Mountains should be the priority area of biodiversity conservation,particularly the southeastern *** proportion of Chinese endemic species inhabiting the Kunlun Mountains and their floristic similarity may indicate that the current patterns of species diversity were favored via species *** Hengduan Mountains,a biodiversity hotspot,is likely the largest source of species colonization of the Kunlun Mountains after the *** net relatedness index indicated that 20 of the 28 communities examined were phylo-genetically dispersed,while the remaining communities were phylogenetically *** nearest taxon index indicated that 27 of the 28 communities were phylogenetically *** results suggest that species colonization and habitat filtering may have contributed to the current plant diversity of the Kunlun Mountains via ecological and evolutionary processes,and habitat filtering may play an impor

关键词： Biodiversity Plant community Kunlun mountains Phylogenetic structure Seed plants

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Review of high thermal conductivity polymer dielectrics for electrical insulation

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High Voltage 2016年第1期1卷 34-42页

作者： Meng Xiao bo Xue du School of Electrical Engineering and Automation Tianjin UniversityTianjin 300072People’s Republic of China Economic and Technical Research Laboratory Jinan Power-supply CompanyJinan 250012ShandongPeople’s Republic of China

Traditional insulation material is thermally insulating and has a low thermal *** miniaturisation and higher power of electrical devices would generate lots of heat,which have created new challenges to safe and stable operation of the *** development of insulating materials with high thermal conductivity provides a new method to solve these *** improvement of thermal conductivity would increase the ability to conduct heat and greatly reduce the operating temperature of the electrical equipment,which could reduce the equipment size and extend service *** the other hand,inorganic thermally conductive particles and the improved thermal conductivity may have great effect on thermal *** this study,the factors affecting the thermal conductivity of dielectric polymer composites were *** thermal conductive polymer and particle-filled thermal conductive composites were *** of thermal conductivity,shape,size,surface treatment of the particle and prepare process on thermal properties of the composites were *** study focused on the electrical and thermal properties of thermally conductive epoxy,polyimide and polyethylene *** failure caused by thermal accumulation is a typical thermal breakdown *** performance of the resistance to tracking failure was studied for these *** results showed that thermal conductive particles improved the resistance to tracking ***,application of thermally conductive epoxy in electrical equipment was discussed.

关键词： composites conductivity electrical

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Recent advances in hyperspectral image processing

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Geo-Spatial Information Science 2012年第3期15卷 143-156页

作者： ZHANG Liangpei du bo State Key Laboratory of Information Engineering in Surveying Mappingand Remote SensingWuhan University129 Luoyu RoadWuhan 430079China School of Computer Science Wuhan University129 Luoyu RoadWuhan 430079China

Hyperspectral images(HSI)provide a new way to exploit the internal physical composition of the land *** basic platform for acquiring HSI data-sets are airborne or spaceborne spectral *** useful information from hyperspectral images can be grouped into four categories.(1)Classification:Hyperspectral images provide so much spectral and spatial information that remotely sensed image classification has become a complex task.(2)Endmember extraction and spectral unmixing:Among images,only HSI have a complete model to represent the internal structure of each pixel where the endmembers are the *** of endmembers from HSI thus becomes the foremost step in interpretation of each *** proper endmembers,the corresponding abundances can also be exactly calculated.(3)Target detection:Another practical problem is how to determine the existence of certain resolved or full pixel objects from a complex *** a reliable rule for separating target signals from all the other background signals,even in the case of low target occurrence and high spectral variation,comprises the key to this problem.(4)Change detection:Although change detection is not a new problem,detecting changes from hyperspectral images has brought new challenges,since the spectral bands are so many,accurate band-to-band correspondences and minor changes in subclass land objects can be depicted in *** this paper,the basic theory and the most canonical works are discussed,along with the most recent advances in each aspect of hyperspectral image processing.

关键词： hyperspectral images classification spectral unmixing endmembers extraction target detection hyperspectral change detection

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A Hybrid Cellular Swarm Optimization Method for Traffic-Light Scheduling

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Chinese Journal of Electronics 2018年第3期27卷 611-616页

作者： HU Wenbin WANG Huan YAN Liping du bo School of Computer Wuhan University

With increasing traffic every day, most cities in the world are facing serious traffic problems, such as traffic accidents, congestion and air pollution. Despite the recent improvement of urban infrastructure, reasonable traffic light scheduling still plays an important role in alleviating these traffic problems. It is a great challenge to schedule a huge number of traffic lights efficiently. To solve this problem, we propose a Hybrid cellular swarm optimization method(HCSO) to optimize the scheduling of urban traffic lights. HCSO achieves an efficient and flexible scheduling, which includes the phase timing scheduling and the phase shifting scheduling. To formulate effective solutions for various traffic problems and achieve a globally dynamic scheduling, flexible and concise transition rules based on Cellular automaton(CA) are *** the Dynamic cellular particle swarm optimization algorithm(DCPSO) is proposed to find the optimal phase timing scheduling efficiently. Moreover, compared with the differential search algorithm method, the genetic algorithm method, the particle swarm optimization method, the comprehensive learning particle swarm optimization method and the random method in real cases, extensive experiments reveal that HCSO achieves obvious improvements under different traffic conditions.

关键词： Transition rules Phase timing scheduling Phase shifting scheduling

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Precipitation behavior of 14H-LPSO structure in Mg–12Gd–2Er–1Zn–0.6Zr Alloy

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Rare Metals 2016年第5期35卷 367-373页

作者： Kai Wen Wen-bo du Ke Liu Zhao-Hui Wang Shu-bo Li College of Materials Science and Engineering Beijing University of Technology

The microstructures of as-cast and as-solution Mg–12Gd–2Er–1Zn–0.6Zr alloys were investigated by optical microscopy（OM）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, highresolution transmission electron microscopy（HRTEM）X-ray diffraction（XRD） and selected-area electron diffraction（SAED） in the present investigation. The results show that the primary eutectic phase Mg5（Gd, Er, Zn） and some flocculent features are found in the as-cast alloy; the SAED pattern indicates that these flocculent features are the dense areas of stacking faults. The 14H-LPSO structure precipitates in the temperature range of 673–793 K, and the volume fraction of 14H-LPSO structure increases with the extension of heating time; however, there is no precipitation of 14H-LPSO structure when the temperature reaches up to 803 K. In addition, the Mg5（Gd, Er, Zn） phase dissolves gradually along with the precipitation of 14H-LPSO structure.

关键词： Mg–Gd–Er–Zn–Zr alloy Dense stacking faults area Heat treatment Microstructure

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Microstructures and mechanical properties of homogenization and isothermal aging Mg–Gd–Er–Zn–Zr alloy

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Rare Metals 2016年第6期35卷 443-449页

作者： Kai Wen Wen-bo du Ke Liu Zhao-Hui Wang Shu-bo Li College of Materials Science and Engineering Beijing University of Technology

The effects of homogenization and isothermal aging treatment on the mechanical properties of Mg-12Gd- 2Er-1Zn-0.6Zr （wt%） alloy were investigated. The precipitated long-period stacking order （LPSO） structure and the aging precipitation sequence of the conditioned alloys were observed and analyzed, respectively. The results indicate that the 14H-LPSO structure occurs after the homogenization treatment and the 131 phase forms after the isothermal aging process. These two independent processes could be controlled by the precipitation temperature range. The significant increase in the elongation of the as-cast alloy after homogenization treatment is attributed to the disappearance of the coarse primary Mgs（Gd, Er, Zn） phase and the presence of the 14H-LPSO structure. The precipitation sequence of the investigated alloy is α-Mg（SSS）/β″（D019）/β′（cbco）/β. Furthermore, the yield tensile strength （YTS） and ultimate tensile strength （UTS） values of the isothermal aging alloy have a great improvement, which could be attributed to the high density of the precipitated β′ phase.

关键词： Magnesium alloys Isothermal aging Mechanical properties Mg-Gd-Er-Zn(Zr) Microstructures

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Real-time visual tracking using complementary kernel support correlation filters

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Frontiers of Computer Science 2020年第2期14卷 417-429页

作者： Zhenyang SU Jing LI Jun CHANG bo du Yafu XIAO School of Computer Science Wuhan UniversityWuhan 430072China Department of Digital Media Technology Huanggang Normal UniversityHuangzhou 438000China

Despite demonstrated success of SVM based trackers,their performance remains a boosting room if carefully considering the following factors:first,the tradeoff between sampling and budgeting samples affects tracking accuracy and efficiency much;second,how to effectively fuse different types of features to learn a robust target representation plays a key role in tracking *** this paper,we propose a novel SVM based tracking method that handles the first factor with the help of the circulant structures of the samples and the second one by a multi-kernel learning ***,we formulate an SVM classification model for visual tracking that incorporates two types of kernels whose matrices are circulant,fully taking advantage of the complementary traits of the color and HOG features to learn a robust target ***,it is fortunate that the SVM model has a closed-form solution in terms of both the classifier weights and the kernel weights,and both can be efficiently computed via fast Fourier transforms(FFTs).Extensive evaluations on OTB100 and VOT2016 visual tracking benchmarks demonstrate that the proposed method achieves a favorable performance against various state-of-the-art trackers with a speed of 50 fps on a single CPU.

关键词： visual tracking SVM correlation filter multikernel learning

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Microstructural control and hardening response of Mg–6Zn–0.5Er–0.5Ca alloy

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Rare Metals 2016年第7期35卷 526-531页

作者： Xiao-Bing Zheng Ke Liu Zhao-Hui Wang Shu-bo Li Wen-bo du School of Material Science and Engineering Beijing University of Technology

The effects of heat treatment on microstructures and hardening response of Mg-6Zn4）.5Er4）.5Ca （wt%） alloy were investigated by optical microscope （OM）, scanning elec- tron microscope （SEM）, and transmission electron microscope （TEM） in this paper. The results show that the Mg（Zn4）.5Er- 0.5Ca alloy contains Mg3Zn6Erx quasicrystalline phase （I- phase） and Ca2Mg6Zn3 phase under as-cast condition. Most of the Ca2Mg6Zn3 phases and I-phases dissolve into matrix during heat treatment at 475 ℃ for 5 h. After the as-solution alloy was aged at 175 ℃ for 36 h, a large amount of MgZn2 precipitate with several nanometers precipitate. It is suggested that the trace addition of Ca results in refining the size of the precipitate, and the presence of the nanoscale MgZn2 phase is the main factor to improve the peak-aged hardness greatly to 87 HV, which in- creases about 40 % compared with that of as-cast alloy.

关键词： Mg-6Zn-0.5Er-0.5Ca alloy Heat treatment Aging hardening

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Microstructure and mechanical properties of AZ31 magnesium alloy reinforced by I-phase

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Rare Metals 2019年第8期38卷 733-738页

作者： Hai-Rong Wu Wen-bo du Shu-bo Li Ke Liu Zhao-Hui Wang School of Materials Science and Engineering Beijing University of Technology

The particles of Mg-Zn-Gd icosahedral quasicrystal master alloy were added into the AZ31 alloy by the repeated plastic working(RPW)process in order to improve the mechanical properties of the AZ31 alloy at room *** microstructure and tensile properties of composites were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and tensile testing machine at room *** results suggest that the RPW process can effectively refine the matrix and make the I-phase particles distribute *** ultimate tensile strength and the yield strength of the composites reach their maximum values of 362.3 and 330.5 MPa,respectively,when the amount of I-phase particles added is10 %.Meanwhile,the elongation of the composites decreases sharply.

关键词： I-phase Reinforced composite Repeated plastic working Mechanical property

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Obtaining Ultra-High Strength and ductility in a Mg–Gd–Er–Zn–Zr Alloy via Extrusion,Pre-deformation and Two-Stage Aging

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Acta Metallurgica Sinica(English Letters) 2021年第1期34卷 39-44页

作者： Lin-Yue Jia Wen-bo du Jin-Long Fu Zhao-Hui Wang Ke Liu Shu-bo Li Xian du College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

The Mg–12Gd–1Er–1Zn–0.9 Zr(wt%)alloy with ultra-high strength and ductility was developed via hot extrusion combined with pre-deformation and two-stage aging *** age-hardening behavior and microstructure evolution were ***-deformation introduced a large number of dislocations,resulting in strain hardening and higher precipitation strengthening in the subsequent two-stage *** a result,the alloy showed a superior strength–ductility balance with a yield strength of 506 MPa,an ultimate tensile strength of 549 MPa and an elongation of 8.2%at room *** finer and denserβ’precipitates significantly enhanced the strength,and the bimodal structure,smallβ-Mg5RE phase as well as denseγ’precipitates ensured the good ductility of the *** is suggested that the combination of pre-deformation and two-stage aging treatment is an eff ective method to further improve the mechanical properties of wrought Mg alloys.

关键词： Magnesium alloys Pre-deformation Two-stage aging Precipitation strengthening Mechanical properties

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