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Vertical differentiation of land cover in the central Himalayas

Journal of Geographical Sciences 2020年第6期30卷 969-987页

作者： ZHANG Yili WU xue zheng Du Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Re-sources ResearchCASBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Characterized by obvious altitudinal variation,habitat complexity,and diversity in land cover,the *** region within the central Himalayas is one of the most sensitive areas to climate change in the *** the same time,because the *** region possesses the most complete natural vertical spectrum in the world,it is also an ideal place to study the vertical structure of alpine land *** this study,land cover data for 2010 along with digital elevation model data were used to define three methods for dividing the northern and southern slopes in the *** region,i.e.,the ridgeline method,the sample transect method,and the sector *** altitudinal distributions of different land cover types were then investigated for both the northern and southern slopes of the *** region by using the above three division methods along with ArcGIS and MATLAB *** results indicate that the land cover in the study region was characterized by obviously vertical zonation with the south-six and north-four pattern of vertical spectrum that reflected both the natural vertical structure of vegetation and the effects of human *** low to high elevation,the main land cover types were forests,grasslands,sparse vegetation,bare land,and glacler/snow *** compositions and distributions of land cover types differed significantly between the northern and southern slopes;the southern slope exhibited more complex land cover distributions with wider elevation ranges than the northern *** area proportion of each land cover type also varied with ***,the vertical distribution patterns of different land cover types on the southern and northern slopes could be divided into four categories,with glaciers/snow cover,sparse vegetation,and grasslands conforming to unimodal *** distribution of bare land followed a unimodal pattern on the southern slope but a bimodal pattern on the northern ***,the use o

关键词： land cover altitudinal zonation central Himalayas Mt.Qomolangma Mt.Makalu Mt.Cho Oyu

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Microstructure and performance of WC-Co-Cr coating with ultrafine/nanocrystalline structures

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Rare Metals 2018年第11期37卷 968-975页

作者： xue-zheng Wang Hai-Bin Wang xue-Mei Liu Chao Hou Xiao-Yan Song College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials Education Ministry of ChinaBeijing University of Technology

The WC-lOCo-4Cr composite powder was synthesized firstly. Then the composite powder was agglomerated to prepare thermal spraying feedstock. The ultrafine/nanostructured WC-lOCo-4Cr coating was prepared by high velocity oxygen fuel thermal spraying. The phase constitution, elemental distribution and microstructure of the coating were characterized by X-ray diffraction and transmission electron microscopy, respectively. The wear resistance and corrosion resistance of the prepared composite coating were tested. The results show that the main phases of the coating include WC, binding phase with partial amorphous structure, with a little WC and Co(Cr)coexisting. The distributions of Co and Cr elements from the phase boundary to the eutectic area then to Co zone were analyzed quantitatively. The mechanisms for the formation of the microstructure and effects of Cr on the performance of the composite coating are proposed.

关键词： In situ synthesis High velocity oxygen fuel Ultrafine/nanostructure Composite coating Phase constitution

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Realization of Face Recognition System Based on Gabor Wavelet and Elastic Bunch Graph Matching

Realization of Face Recognition System Based on Gabor Wavele...

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第25届中国控制与决策会议

作者： lv xue-fang Ping Tao Shandong Foreign Trade Vocational College Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of Sciences

ISBN: (纸本)9781467355339

This paper studies the face recognition system based on the Gabor wavelet and elastic bunch graph matching, and gives the realization method of the system. In this system, a face is expressed by a set of feature points, each of these feature point can be described as a Gabor Jet. For the training images, feature points can be located manually, and then get Gabor. For the sample face image, the corresponding feature points are searched automatically, which coarse positions are located by the training face structure knowledge, and then we use elastic bunch graph to adjust the accurate positions. At last Gabor Jets are obtained from the sample face images. The similar degree of the sample images is expressed by the related measure function of Gabor jets. The experiments show that the face recognition system tested on the face FERET database is efficiency.

关键词： Face Recognition Elastic bunch graph matching Gabor wavelets

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Hole surface strengthening mechanism and riveting fatigue life of CFRP/aluminum stacks in robotic rotary ultrasonic drilling

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Chinese Journal of Aeronautics 2023年第10期36卷 471-484页

作者： Song DONG Wenhe LIAO Kan zheng Feng xue Lianjun SUN School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Carbon fiber reinforced plastic(CFRP)and aluminum stacks are widely used in aviation industry due to light weight and high *** of rivet holes need to be drilled on body materials,and more than 80%of fatigue cracks occur at the connection holes,so the damage and residual stress of hole surface have crucial effect on the riveting fatigue life of CFRP/aluminum stacks and the flight ***,robotic rotary ultrasonic drilling(RRUD)technology is a promising method to machine the ***,the hole surface strengthening mechanism in RRUD and the service performance of the riveting joint are not ***,in this paper,the hole surface strengthening mechanism of RRUD for CFRP/aluminum stacks is investigated,a theoretical residual stress model is established,and the fatigue life experiment of riveted joints is ***,analysis on residual stress in RRUD is carried out with consideration of strengthening force and cutting *** stress model is established based on the calculation of elastic stress,plastic stress and stress *** experiment results show that ultrasonic vibration changes residual stress from tensile stress to compressive *** the same time,comparative damage analysis of CFRP hole exit and hole surface in robotic conventional drilling(RCD)and RRUD is ***,fatigue strength experiments of riveted joints are conducted for performance *** results indicate that fatigue life of single-hole riveted joints is increased by 68%with ultrasonic vibration,and four-hole riveted joint arranged according to aerospace design standards is increased by more than 86%.

关键词： CFRP/aluminum stacks Drilling damage Residual stress Riveting fatigue life Robotic rotary ultrasonic drilling

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A highly alkaline-stable metal oxide@metal–organic framework composite for high-performance electrochemical energy storage

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National Science Review 2020年第2期7卷 305-314页

作者： Shasha zheng Qing Li Huaiguo xue Huan Pang Qiang Xu School of Chemistry and Chemical Engineering and Institute for Innovative Materials and Energy Yangzhou University AIST-Kyoto University Chemical Energy Materials Open Innovation Laboratory National Institute of Advanced Industrial Science and Technology

Most metal-organic frameworks(MOFs) hardly maintain their physical and chemical properties after exposure to alkaline aqueous solutions,thus precluding their use as potential electrode materials for electrochemical energy storage ***,we present the design and synthesis of a highly alkaline-stable metal oxide@MOF composite,CoOnanocube@Co-MOF(CoO@Co-MOF),via a controllable and facile one-pot hydrothermal method under highly alkaline *** obtained composite possesses exceptional alkaline stability,retaining its original structure in 3.0 M KOH for at least 15 *** from the exceptional alkaline stability,unique structure,and larger surface area,the CoO@Co-MOF composite shows a specific capacitance as high as 1020 F gat 0.5 A gand a high cycling stability with only 3.3% decay after 5000 cycles at 5 A *** as-constructed solid-state flexible device exhibits a maximum energy density of 21.6 mWh cm.

关键词： metal–organic framework metal oxide composite electrochemical energy storage flexible supercapacitor

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Hierarchical Ni-plated melamine sponge and MXene film synergistically supported phase change materials towards integrated shape stability,thermal management and electromagnetic interference shielding

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Journal of Materials Science & Technology 2023年第1期132卷 132-143页

作者： Ziling Cheng Guojun Chang Bai xue Lan Xie Qiang zheng State Key Laboratory of Public Big Data Guizhou UniversityGuiyang 550025China Department of Polymer Materials and Engineering College of Materials and MetallurgyGuizhou UniversityGuiyang 550025China National Engineering Research Center for Compounding and Modification of Polymer Materials National and Local Joint Engineering Research Center for Functional Polymer Membrane Materials and Membrane ProcessesGuiyang 550014China College of Polymer Science and Engineering Zhejiang UniversityHangzhou 310000China

Along with the integrated and miniaturized development of advanced electronic devices,phase change materials(PCMs)simultaneously with efficient thermal management and high electromag-netic interference(EMI)shielding effectiveness(SE)are ungently ***,the shape-stabilized MXene/Ni-platted melamine sponge/Regenerated cellulose/Graphene nanoplate/Polyethylene glycol(MX/Ni@MS/RCG/PEG)composite PCMs comprising hierarchical Ni@MS/RCG and MXene film were fabricated via a facile encapsulation *** Ni@MS/RCG hybrid aerogel was prepared by electroless plating and sol-gel methods,and MXene film was obtained using vacuum-assisted filtra-tion *** synergistic effect of conductive Ni@MS/RCG networks and tight MXene film endows MX/Ni@MS/RCG/PEG composite PCMs with good shape stability,high cyclic reliability,large latent heat of phase change(154.3 J g^(–1)),excellent thermal conductivity(TC,0.47 W m^(–1)K^(–1))and favorable EMI shield-ing performance(32.7 dB).The TC of acceptable 0.47 W m^(–1)K^(–1)is observed for MX/Ni@MS/RCG-5/PEG at a rather low GNP content of merely 0.39 wt%.In addition,the temperature variation of MX/Ni@MS/RCG-5/PEG is a lot faster than that of pure PEG in the heating/cooling process,revealing the remarkable energy storage and release efficiency for the composite *** investigation has taken an important step to-wards shape-stabilized composite PCMs with both effective thermal management and high EMI SE for promising applications in electronic packaging and advanced energy.

关键词： Phase change material Thermal management Electromagnetic interference shielding Shape stability Encapsulation

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Multi-heterointerfaces for selective and efficient urea production

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National Science Review 2023年第2期10卷 212-223页

作者： Danyan Zhang Yurui xue Xuchen zheng Chao Zhang Yuliang Li Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences Shandong Provincial Key Laboratory for Science of Material Creation and Energy Conversion Science Center for Material Creation and Energy Conversion School of Chemistry and Chemical EngineeringShandong University

A major impediment to industrial urea synthesis is the lack of catalysts with high selectivity and activity,which inhibits the efficient industrial production of ***,we report a new catalyst system suitable for the highly selective synthesis of industrial urea by in situ growth of graphdiyne on the surface of cobalt-nickel mixed *** a catalyst is a multi-heterojunction interfacial structure resulting in the obvious incomplete charge-transfer phenomenon between a graphdiyne and metal oxide interface and multiple intermolecular *** intrinsic characteristics are the origin of the high performance of the *** on the me chanism reve al that the catalyst could effectively optimize the adsorption/desorption capacities of the intermediate and promote direct C-N coupling by significantly suppressing by-product reactions toward the formation of H2,CO,N2and *** catalyst can selectively synthesize urea directly from nitrite and carbon dioxide in water at room temperature and pressure,and exhibits a record-high Faradaic efficiency of 64.3%,nitrogen selectivity(Nurea-selectivity) of86.0%,carbon selectivity(Curea-selectivity) of ～100%,as well as urea yield rates of 913.2 μg h-1mgcat-1and remarkable long-term stability.

关键词： porous materials carbon materials multi-heterointerfaces urea synthesis high-performance conversion

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Correspondence between the large volcanic eruptions and ENSO events over AD 1525-2000

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Journal of Geographical Sciences 2020年第1期30卷 103-118页

作者： FANG Xiuqi zheng xue ZHANG Xing Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster Ministry of EducationBeijing Normal UniversityBeijing 100875China

ENSO is an interannual mode which may be affected by external forcing, such as volcanic eruptions. Based on the reconstructed volcanic eruptions chronology and ENSO sequences, both 195 large volcanic eruptions (VEI≥4) and 398 ENSO (El Niño and La Niña) events were extracted from 1525 to 2000. An analysis of the correspondence between the large volcanic eruptions and ENSO events was performed by matching the large volcanic eruptions with the types and magnitudes of ENSO events present in the 0-2 years after the eruptions. The results show the following: (1) The percentages of ENSO events within the 3 years after the large eruptions had increased to 68.3% from 31.7% compared with those with no-eruptions in the previous 0-2 years. In addition, the ratio of El Niño to La Niña events turned from 2:3 to 1:1, and more El Niño events occurred in the 0 year after eruptions in the low-latitudes of the Northern Hemisphere and in the tropics but more La Niña events occurred in the 0 year after in the high-latitudes of the Northern Hemisphere and the Southern Hemisphere. (2) After the eruptions, the weak (W) El Niño events had increased by 8 percentage points and the very strong (VS) El Niño events had decreased by 10 percentage points; conversely, there was a decrease by 15 percentage points of the weak La Niña events and an increase by 11.4 percentage points of the very strong La Niña events. Specifically, the percentages of strong La Niña events increased to a peak at 1 (+1) year after the eruptions. (3) The percentage of eruptions followed by single-year ENSO was the greatest. The percentage of ENSO events that occurred in the consecutive 2 years following an eruption was approximately equal to the percentage of events that occurred consecutively 3 years following an eruption, and both sets of ENSO magnitudes showed a decreasing trend.

关键词： ENSO large volcanic eruptions(VEI≥4) regional volcanoes relationship

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A universal elliptical disc(UED)model to represent natural rock fractures

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International Journal of Mining Science and Technology 2022年第2期32卷 261-270页

作者： Jun zheng Jichao Guo Jiongchao Wang Honglei Sun Jianhui Deng Qing lv Department of Civil Engineering Zhejiang UniversityHangzhou 310058China Center for Balance Architecture Zhejiang UniversityHangzhou 310007China College of Civil Engineering Zhejiang University of TechnologyHangzhou 310023China State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource&HydropowerSichuan UniversityChengdu 610065China

Since natural fractures are often non-equidimensional,the circular disc model still has great *** contrast,the elliptical disc model is more applicable to representing natural fractures,especially for slender *** paper developed a universal elliptical disc(UED)model by incorporating the center point,size,and azimuth of fractures as ***,with respect to the azimuth of elliptical fractures in three-dimensional(3D)space,we proposed a paradigm to construct its probability density function(PDF)by coupling the orientation and rotation angle of long axis based on three coordinate *** illustrate the construction process of the PDF of the fracture azimuth,we took the orientation following the Fisher distribution and the rotation angle following Von Mises distribution as an example.A rock slope is used to show the use of the developed UED model,and the 3D DFNs for the slope rock mass are generated by Monte Carlo *** addition,the DFNs for the rock mass are also generated based on the existing circular disc model and non-universal elliptical disc *** comparison results from the three models clearly illustrate the superiority of the UED model over the existing circular and non-universal elliptical disc models.

关键词： Discrete fracture networks Rock mass Discontinuity Elliptical disc model Fisher distribution Monte Carlo simulation

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Flotation behaviors of chalcopyrite and galena using ferrate(Ⅵ) as a depressant

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International Journal of Mining Science and Technology 2023年第1期33卷 93-103页

作者： Yongxing zheng Yusong Huang Panjin Hu Xianhui Qiu Jinfang lv Lingyun Bao State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and TechnologyKunming 650093China Faculty of Land Resource Engineering Kunming University of Science and TechnologyKunming 650093China Faculty of Resource and Environmental Engineering Jiangxi University of Science and TechnologyGanzhou 341000China

This paper investigated the effects of potassium ferrate(PF)on the flotation performances of chalcopyrite and *** flotation results showed that PF obviously depressed galena,but had little effects on the floatability of chalcopyrite within pH range of 4.0–*** potential tests showed that the addition of PF induced the formation of more amounts of hydrophilic species on the surface of galena under an alkaline *** grade O-isopropyl-N-ethyl thionocarbamate(IPETC)chemically adsorbed on the surface of the PF-treated chalcopyrite and galena after its *** angle measurements showed that with the addition of PF,the contact angle of the galena surface significantly decreased compared with the chalcopyrite *** electrochemical impedance spectroscopy(LEIS)tests showed that the addition of PF increased the impedance of the galena surface.X-ray photoelectron spectroscopy(XPS)analyses revealed that the formation of hydrophilic species,namely lead sulfite,lead hydroxide and ferric hydroxide,on the galena surface,decreased its floatability in the presence of PF,while the formation of hydrophobic species,namely copper disulfide and elemental sulfur,on the chalcopyrite surface,maintained its ***,a descriptive model for the reaction of PF with chalcopyrite and galena was proposed.

关键词： Flotation Chalcopyrite Galena Potassium ferrate

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