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1990-2017年通榆县土地沙漠化的时空变化及其驱动因素

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贵州农业科学 2020年第6期48卷 125-130,I0001,F0003页

作者：商贝贝李晓燕杨黎敏康应东吉林大学地球科学学院吉林长春130012 中国科学院东北地理与农业生态研究所吉林长春130102

为通榆县土地沙漠化防治及生态环境治理提供技术支撑,选择吉林省西部典型半干旱区通榆县为研究区,以Landsat TM/OLI影像为主要数据源,提取研究区1990-2017年不同程度沙漠化土地信息,采用沙漠化指数及方差分析等方法,研究通榆县土地沙漠... 详细信息

为通榆县土地沙漠化防治及生态环境治理提供技术支撑,选择吉林省西部典型半干旱区通榆县为研究区,以Landsat TM/OLI影像为主要数据源,提取研究区1990-2017年不同程度沙漠化土地信息,采用沙漠化指数及方差分析等方法,研究通榆县土地沙漠化的时空变化及其驱动因素。结果表明:1990-2017年,通榆县沙漠化土地类型以农田沙漠化和灌丛沙漠化为主,其面积从1990年的25.78万hm^2减至2017年的25.10万hm^2,总体呈先增后减趋势,2000年时沙漠化面积达最大,为30.85万hm^2;土地沙漠化程度,轻度面积呈先增后减趋势,中度面积呈持续增加趋势,但重度和严重沙漠化土地面积呈减少趋势。1990年、2000年、2010年和2017年沙漠化指数分别为0.62,0.70,0.66和0.53,2000年以后总体沙漠化程度有所减缓;土壤类型、高程、坡度、气温和归一化植被指数(NDVI)、耕地面积、载畜量及政策是影响通榆县土地沙漠化空间差异的主要因素。

关键词：土地沙漠化时空演变驱动因素通榆吉林

Geometric positioning integrating optical satellite stereo imagery and a global database of ICESat-2 laser control points:A framework and key technologies

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Geo-Spatial Information Science 2023年第2期26卷 206-217页

作者： Mi Wang Yu Wei yingdong Pi State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina School of Resource and Environmental Sciences Wuhan UniversityWuhanChina

Block Adjustment(BA)is one of the essential techniques for producing high-precision geospatial 3D data products with optical stereo satellite *** block adjustment with few ground-control points or without ground control,the vertical error of the model is the decisive factor that constrains the accuracy of 3D data *** elevation data obtained by spaceborne laser altimeter have the advantages of short update periods,high positioning precision,and low acquisition cost,providing sufficient data support for improving the elevation accuracy of stereo models through the combined *** paper proposes a geometric positioning model based on the integration of Optical Satellite Stereo Imagery(OSSI)and spaceborne laser altimeter ***,we elaborate the principle and necessity of this work through a literature review of existing ***,the framework of our geo-positioning ***,four key technologies of the proposed model are expounded in order,including the acquisition and management of global Laser Control Points,the association of LCPs and OSSI,the block adjustment model combining LCPs with OSSI,and the accuracy estimation and quality control of the combined ***,the combined BA experiment using Ziyuan-3(ZY-3)OSSI and ICESat-2 laser data was carried out at the testing site in Shandong Province,*** results prove that our method can automatically select LCPs with high *** elevation deviation of the combined BA eventually achieved the Mean Error(ME)of 0.06 m and the Root Mean Square Error(RMSE)of 1.18 m,much lower than the ME of 13.20 m and the RMSE of 3.88 m before the block adjustment.A further research direction will be how to perform more adequate accuracy analysis and quality control using massive laser points as checkpoints.

关键词： Spaceborne laser altimeter ICESat-2 optical stereo imagery ZY-3 combined block adjustment block adjustment without ground control geometric positioning stereo mapping

On proactive eavesdropping using anti-relay-selection jamming in multi-relay communication systems

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Science China(Information Sciences) 2019年第4期62卷 157-166页

作者： yingdong HU Ruifeng GAO Ye LI Shibing ZHANG School of Electronic and Information Nantong University

This paper considers a multi-relay legitimate surveillance system, where a suspicious link may transmit illegal information with the help of relays and a legitimate monitor aims at intercepting the information. We assume that the relay selection method is adopted by the suspicious link to improve the efficiency of the information transmission. We propose anti-relay-selection(ARS) jamming strategies for two different information transmission scenarios, namely the event-based information and content-based information. Beamforming vector of jamming is optimized and the iterative algorithms are used to improve the jamming efficiency. We demonstrate the effectiveness and the superiority of the ARS jamming strategies through numerical results and simulations.

关键词： physical layer security proactive eavesdropping anti-relay-selection jamming multi-relay beamforming

Design and modeling of a free-piston engine generator

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Frontiers in Energy 2023年第6期17卷 811-821页

作者： Jinlong WANG Jin XIAO yingdong CHENG Zhen HUANG Key Laboratory for Power Machinery and Engineering(Ministry of Education) Shanghai Jiao Tong UniversityShanghai 200240China

Free-piston engine generators (FPEGs) can be applied as decarbonized range extenders for electric vehicles because of their high thermal efficiency, low friction loss, and ultimate fuel flexibility. In this paper, a parameter-decoupling approach is proposed to model the design of an FPEG. The parameter-decoupling approach first divides the FPEG into three parts: a two-stroke engine, an integrated scavenging pump, and a linear permanent magnet synchronous machine (LPMSM). Then, each of these is designed according to predefined specifications and performance targets. Using this decoupling approach, a numerical model of the FPEG, including the three aforementioned parts, was developed. Empirical equations were adopted to design the engine and scavenging pump, while special considerations were applied for the LPMSM. A finite element model with a multi-objective genetic algorithm was adopted for its design. The finite element model results were fed back to the numerical model to update the LPMSM with increased fidelity. The designed FPEG produced 10.2 kW of electric power with an overall system efficiency of 38.5% in a stable manner. The model provides a solid foundation for the manufacturing of related FPEG prototypes.

关键词： free-piston engine generator linear permanent magnet synchronous machine system design numerical model finite element method

A novel compilation method of comprehensive mission spectrum of aero-engine maneuvering load based on use-related mission segment

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Chinese Journal of Aeronautics 2023年第3期36卷 161-170页

作者： Xuming NIU Qi LU Zhigang SUN yingdong SONG Jiangsu Province Key Laboratory of Aerospace Power System and College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Laboratory of Aero-Engine Thermal Environment and Structure Ministry of Industry and Information Technology College of Energy and Power EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China College of Energy and Power Engineering and State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Comprehensive Mission Spectrum(CMS)of an aero-engine can reflect the usage characteristics of the *** can provide load input for engine life prediction and accelerated mission *** this paper,a novel compilation method of CMS of aero-engine maneuvering load based on mission segment is ***,the use-related Typical Mission Segment(TMS)of maneuvering load is divided and identified according to spectral ***,the mathematical model of different kinds of TMS are established based on stochastic process ***,the CMS of maneuvering load is compiled based on *** proposed method can accurately quantify the compilation of *** compiled CMS shows good agreement with the original load *** to damage consistency inspection,the compiled CMS is consistent with the damage caused by the original load spectrum in terms of low cycle fatigue.

关键词： Aero-engine Comprehensive mission spectrum Maneuvering load Spectrum compilation Typical mission segment

Lyapunov Stability Analysis for Incommensurate Nabla Fractional Order Systems

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Journal of Systems Science & Complexity 2023年第2期36卷 555-576页

作者： WEI Yiheng ZHAO Xuan WEI yingdong CHEN Yangquan School of Mathematics Southeast UniversityNanjing 211189China Department of Automation University of Science and Technology of ChinaHefei 230026China School of Engineering University of CaliforniaMercedUSA

This paper investigates the problem of stability analysis for a class of incommensurate nabla fractional order *** particular,both Caputo definition and Riemann-Liouville definition are under *** the convex assumption,several elementary fractional difference inequalities on Lyapunov functions are *** to the essential features of nabla fractional calculus,the sufficient conditions are given first to guarantee the asymptotic stability for the incommensurate system by using the direct Lyapunov *** substantiate the efficacy and effectiveness of the theoretical results,four examples are elaborated.

关键词： Asymptotic stability attractiveness convex functions difference inequality incommensurate nabla fractional order systems Lyapunov method

Distribution and differentiation of bone marrow-derived mesenchymal stem cells in vivo after intraperitoneal and tail vein injection into rats in the recovery phase of stroke: Which path is better?

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Neural Regeneration Research 2010年第13期5卷 965-969页

作者： Yan Liu yingdong Zhang Department of Neurology Nanjing Brain Hospital Nanjing 210029 Jiangsu Province China

BACKGROUND： Stereotactic injection （striatum or lateral ventricle） and vascular injection （ tail vein or carotid artery） are now often used in cellular therapy for cerebral infarction. Stereotactic injection can accurately deliver cells to the infarct area, but requires a stereotactic device and causes secondary trauma; vascular injection is easy and better for host neurological deficit recovery, but can cause thrombosis. OBJECTIVE： To compare the therapeutic potential of adult bone marrow-derived mesenchymal stem cells （BMSCs） transplantation by intraperitoneal versus intravenous administration to cerebral ischemic rats. DESIGN, TIME AND SE＇B＇ING： A randomized controlled animal experiment was performed at the Cell Room and Pathology Laboratory, Brain Hospital Affiliated to Nanjing Medical University from November 2007 to September 2008. MATERIALS： BMSCs were derived from 20 healthy Sprague-Dawley rats aged 4-6 weeks. METHODS： Forty-five adult middle cerebral artery occlusion （MCAO） rats were randomly divided into control, intravenous and intraperitoneal injection groups, with 15 rats in each group. At 21 days after modeling, rats in the control group received 1 mL of 0.01 mol/L phosphate buffered saline via tail vein injection and each experimental rat received 4 x 106 BMSCs labeled by bromodeoxyuridine （BrdU） via intravenous or intraperitoneal injection. MAIN OUTCOME MEASURES： Angiogenin expression and survival of transplanted cells were measured by immunohistochemical staining of brain tissue in infarction hemisphere at 7, 14 or 21 days after BMSC transplantation. Co-expression of BrdU/microtubule-associated protein 2 or BrdU/glial fibrillary acidic protein was observed by double-labeled immunofluorescence of cerebral cortex. Evaluation of nerve function adhesion-removal test was performed on the 14 or 21 days after BMSCs treatment. using the neurological injury severity score and the 1st and 21st day before and after MCAO, and at 3, 7 RESULTS： Angiogenin-positiv

关键词： bone marrow-derived mesenchymal stem cells brain ischemia functional recovery neural differentiation angiogenesis neural regeneration

A Novel ISSA–DELM Model for Predicting Rock Mass Permeability

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2825-2848页

作者： Chen Xing Leihua Yao yingdong Wang School of Engineering and Technology China University of Geosciences(Beijing)Beijing100083China Beijing Engineering Corporation Limited Beijing100024China

In pumped storage projects,the permeability of rock masses is a crucial parameter in engineering design and *** rock mass permeability coefficient(K)is influenced by various geological parameters,and previous studies aimed to establish an accurate relationship between K and geological *** study uses the improved sparrow search algorithm(ISSA)to optimize the parameter settings of the deep extreme learning machine(DELM),constructing a prediction model with flexible parameter selection and high ***,the Spearman method is applied to analyze the correlation between geological parameters.A sample database is built by comprehensively selecting four geological indexes:burial depth,rock quality designation(RQD),fracture density characteristic index(FD),and rock mass integrity designation(RID).Hence,the defects of the sparrow search algorithm(SSA)are enhanced using the improved strategy,and the initial input weights of the DELM are ***,the proposed ISSA–DELM model is employed to predict the permeability coefficient of rock mass in the entire study *** results showed that the predictive performance of the model is superior to that of the DELM and SSA–***,this model successfully provides insights into the distribution characteristics of rock mass permeability at engineering sites.

关键词： ISSA DELM rock mass permeability coefficient geological parameter correlation analysis

Research on failure criterion of composite based on unified macro- and micro-mechanical model

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Chinese Journal of Aeronautics 2013年第1期26卷 122-129页

作者： Sun Zhigang Zhao Long Chen Lei Song yingdong College of Energy and Power Engineering and State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics

A new unified macro- and micro-mechanics failure analysis method for composite structures was developed in order to take the effects of composite micro structure into consideration. In this method, the macro stress distribution of composite structure was calculated by commercial finite element analysis software. According to the macro stress distribution, the damage point was searched and the micro-stress distribution was calculated by reformulated finite-volume direct averaging micromechanics （FVDAM）, which was a multi-scale finite element method for composite. The micro structure failure modes were estimated with the failure strength of constituents. A unidirectional composite plate with a circular hole in the center under two kinds of loads was analyzed with the traditional macro-mechanical failure analysis method and the unified macro- and micro-mechanics failure analysis method. The results obtained by the two methods are consistent, which show this new method＇s accuracy and efficiency.

关键词： Composite Finite-volume direct averaging micromechanics Mechanics failure model Multi-scale finite element Unified macro and micro