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Coupled effects of climate change and human activities on vegetation dynamics in the Southwestern Alpine Canyon Region of China

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Journal of Mountain Science 2024年第10期21卷 3234-3248页

作者： LAI Jinlin qi shi School of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083China

The driving effects of climate change and human activities on vegetation change have always been a focal point of ***,the coupling mechanisms of these driving factors across different temporal and spatial scales remain *** Southwestern Alpine Canyon Region of China(SACR),as an ecologically fragile area,is highly sensitive to the impacts of climate change and human *** study constructed a vegetation cover dataset for the SACR based on the Enhanced Vegetation Index(EVI)from 2000 to *** autocorrelation,Theil-Sen trend,and Mann-Kendall tests were used to analyze the spatiotemporal characteristics of vegetation cover *** main drivers of spatial heterogeneity in vegetation cover were identified using the optimal parameter geographic detector,and an improved residual analysis model was employed to quantify the relative contributions of climate change and human activities to interannual vegetation cover *** main findings are as follows:Spatially,vegetation cover exceeds 60%in most areas,especially in the southern part of the study ***,the border area between Linzhi and Changdu exhibits lower vegetation *** factors are the primary drivers of spatial heterogeneity in vegetation cover,with temperature having the most significant influence,as indicated by its q-value,which far exceeds that of other ***,the interaction q-value between the two factors significantly increases,showing a relationship of bivariate enhancement and nonlinear *** terms of temporal changes,vegetation cover shows an overall improving trend from 2000 to 2020,with significant increases observed in 68.93%of the study *** these,human activities are the main factors driving vegetation cover change,with a relative contribution rate of 41.31%,while climate change and residual factors contribute 35.66%and 23.53%,*** thoroughly exploring the coupled mechanisms of vegetation change,this

关键词： Enhanced vegetation index Climate change Human activities Spatial heterogeneity Coupled mechanisms

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Network selection based on multiple attribute decision making and group decision making for heterogeneous wireless networks

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 92-98,114页

作者： shi Zheng ZHU qi Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Laboratory on Wideband Wireless Communications and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing 210003 China

One of the key issues for radio resources management is network selection strategy in heterogeneous scenarios. In order to provide ubiquitous service, the paper puts forward a network selection algorithm based on multiple attribute decision making （MADM） and group decision making （GDM）. Firstly, the proposed algorithm acquires attribute weights＇ vectors of the subjective and objective decision makers based on MADM, and then the two attribute weights＇ vectors are synthesized to be a new attribute weights＇ vector by using GDM. Considering that the results of GDM should be reasonable and convincible, the criterion of consistency is adopted for judging the compatibility of group judgments. More specit]cally, the algorithm takes into account not only objective attributes of networks but also the preference of subscribers and traft]c class Hence it guarantees that the subscribers can not select the networks with poor performance depending on their preference. The simulation results show that the proposed algorithm can effectively reduce the handoff number and provide subscribers with satisfactory quality of service （QoS）.

关键词： heterogeneous wireless networks group decision making compatibility criterion analytic hierarchy process entropy method

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Folded or nonfolded fluorophores incorporating naphthalene:Their fluorescent quenching driven by charge transfer or co-aggregation in the aqueous-organic binary solvent

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Chinese Chemical Letters 2010年第2期21卷 221-224页

作者： Zhou, qi Zhong Liu, shi Yong Zhao, Shu min Jiang, Huang Jiang Taizhou Univ Dept Chem Taizhou 317000 Peoples R China Zhejiang Univ Dept Chem Hangzhou 310027 Peoples R China

Folded or nonfolded fluorophores incorporating naphthalene were synthesized and characterized by steady state fluorescence *** as an excellent quenching reagent quenched the fluorescence of Nel6 or nDs(n = 1-4) driven by charge *** aggregation of nDs,α-CD did not quench the fluorescence of *** lower concentration,the quenching tendency ofα-CD against nDs is 2D>3D>4D,while at higher concentration,the tendency is 2D<3D<4D.α-CD showed the selective recognition on its flu...

关键词： Fluorophore Fluorescent quenching Charge transfer Co-aggregation Selective recognition

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基于多比例尺地形图的SPOT5影像几何纠正方法

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上海师范大学学报（自然科学版） 2011年第4期40卷 421-426页

作者：施敏琦林文鹏温家洪宗玮李厚增上海师范大学旅游学院上海200234

几何纠正是遥感信息处理中的重要环节,它直接关系到信息提取的精度与实用程度.而现实中,由于地形图绘制年代久远,且保密性较高,往往会出现缺失而不能满足纠正精度的情况.据此本研究在上海地区1∶25 000大比例尺地形图缺失,1∶100 000地... 详细信息

几何纠正是遥感信息处理中的重要环节,它直接关系到信息提取的精度与实用程度.而现实中,由于地形图绘制年代久远,且保密性较高,往往会出现缺失而不能满足纠正精度的情况.据此本研究在上海地区1∶25 000大比例尺地形图缺失,1∶100 000地形图不能满足SPOT5影像纠正精度的情况下,结合ArcGIS、ENVI软件采用多种例尺地形图对SPOT5影像进行几何纠正,并对纠正精度进行了对比分析.结果表明:将多比例尺地形图综合纠正能使精度控制在1个像元之内,由此确立了现有条件下的最佳方案,为地形图缺失情况下平原地区的几何纠正提供了思路.

关键词：几何纠正 SPOT5影像多比例尺地形图精度平原地区

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湿地表层底泥溶解性有机质荧光组分特征及与真菌群落相关性

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光谱学与光谱分析 2025年第1期45卷 191-196页

作者：史传奇李艳孟令波胡钰金梁哈尔滨学院黑龙江省寒区湿地生态与环境研究重点实验室黑龙江哈尔滨150086 北京市农林科学院植物营养与资源环境研究所北京100097 东北农业大学资源与环境学院黑龙江哈尔滨150038

溶解性有机质(DOM)和微生物群落间具有紧密联系,DOM为微生物提供营养,微生物代谢可转化DOM,两者间相互作用共同影响着生态系统的物质循环与能量流动。采集北方寒区天然湿地(河流湿地,HL;湖泊湿地,HP)和人工湿地(水田,ST;鱼塘,YT)表层(0~... 详细信息

溶解性有机质(DOM)和微生物群落间具有紧密联系,DOM为微生物提供营养,微生物代谢可转化DOM,两者间相互作用共同影响着生态系统的物质循环与能量流动。采集北方寒区天然湿地(河流湿地,HL;湖泊湿地,HP)和人工湿地(水田,ST;鱼塘,YT)表层(0~15 cm)底泥样品,采用三维荧光光谱法和高通量测序技术,揭示不同类型湿地表层底泥DOM荧光光谱及真菌群落特征,并进一步分析其相关性。结果表明:表层底泥DOM荧光光谱共识别出4种荧光组分,包括类富里酸(C1)、类胡敏酸(C2)和类蛋白质(类色氨酸C3和类酪氨酸C4)。C1和C2成显著正相关,而与类蛋白质间相关性不显著。C1的相对浓度高于C2,C3和C4的相对浓度接近。YT中DOM浓度相对高于其余样品,HL和HP中C2和类蛋白质相对浓度具有显著差异,ST和YT中C1、C2和C3的相对浓度均具有显著差异。湿地表层底泥真菌群落优势门(除未分类类群)为子囊菌门(Ascomycota)、担子菌门(Basidiomycota)、罗兹菌门(Rozellomycota)。YT中真菌群落Chao1丰富度指数、Shannon多样性指数显著较低,而Simpson优势度指数显著较高,HP中Shannon多样性指数显著高于其余样品。C1、C2与真菌群落多样性显著相关,C2与真菌群落组成显著相关,而类蛋白质与真菌群落无显著相关性。C1、C2与子囊菌门均成显著正相关,C1与壶菌门(Chytridiomycota)和单毛壶菌门(Monoblepharomycota)成显著负相关,C2与担子菌门、罗兹菌门、壶菌门、单毛壶菌门均成显著负相关。因此,真菌群落对DOM相对大分子量荧光组分的相对浓度具有显著影响。针对北方寒区典型湿地表层底泥DOM荧光光谱特征及与真菌群落相关性进行分析,为湿地环境监测与评价提供基础数据,并为湿地合理利用提供理论参考。

关键词：三维荧光光谱溶解性有机质荧光组分真菌

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FEM Simulation of the Hydrogen Diffusion in X80 Pipeline Steel During Stacking for Slow Cooling

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Acta Metallurgica Sinica(English Letters) 2014年第3期27卷 416-421页

作者： Zhenyi Huang qi shi Fuqiang Chen Yunfeng shi School of Metallurgical Engineering Anhui University of Technology Heavy Plate Mill Baoshan Iron and Steel Co. Ltd

The influence of temperature on the hydrogen diffusion behavior in X80 pipeline steel during stacking for slow cooling was studied using electrochemical penetration method, the temperature field and the hydrogen diffusion in this pipeline steel during stacking for slow cooling were simulated by ABAQUS finite element method （FEM） software. The results show that in this process there is a reciprocal relationship between the natural logarithm of hydrogen diffusion coefficient and temperature. The cooling rate decreases gradually with the increase of steel plate thickness. The hydrogen content is higher at high temperature （500-400 ℃） than that in low temperature region （300-100 ℃）. The FEM simulation results are consistent with the experimental ones, and the model can be used to predict the hydrogen diffusion behavior in industrial production of X80 pipeline steel.

关键词： X80 pipeline steel Stacking Slow cooling Hydrogen diffusion Finite element method (FEM) Electrochemical penetration

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Event-triggered robust MPC of nonlinear cyber-physical systems against DoS attacks

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Science China(Information Sciences) 2022年第1期65卷 22-38页

作者： qi SUN Jicheng CHEN Yang shi Department of Mechanical Engineering University of Victoria

This paper proposes an event-triggered robust nonlinear model predictive control(NMPC) framework for cyber-physical systems(CPS) in the presence of denial-of-service(Do S) attacks and additive disturbances. In the framework, a new robustness constraint is introduced to the NMPC optimization problem in order to deal with additive disturbances, and a packet transmission strategy is designed for NMPC such that Do S attacks can be tackled. Then, an event-triggered mechanism, which accommodates Do S attacks occurring in the communication network, is proposed to reduce the communication cost for resource-constrained CPSs. Besides, we prove that the NMPC algorithm is recursively feasible and the closed-loop system is input-to-state practical stable under some sufficient conditions. Simulation examples and comparisons are conducted to show the effectiveness of the proposed NMPC algorithm.

关键词： cyber-physical systems nonlinear model predictive control event-triggered mechanism robust control denial-of-service attacks

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Dynamics modeling and pressure control of composites tape winding system based on LQSMC

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Chinese Journal of Aeronautics 2020年第2期33卷 740-748页

作者： qi HONG Yaoyao shi Danni LU The Key Laboratory of Contemporary Design and Integrated Manufacturing Technology ministry of Education Northwestern Polytechnical UniversityXi’an 710072China

Pressure fluctuations during the composite fiber winding process seriously affect the produces compactness strength,fatigue resistance,stress uniformity,and resin *** accuracy of pressure control systems is affected by nonlinear disturbances,such as friction,parameter perturbation,and measurement noise.A robust control algorithm based on linear quadratic optimal control and sliding mode control(LQSMC)is proposed to overcome these *** method is based on the system state space expression and linear quadratic optimal *** state space model of the system is improved by using a Kalman filter and control input for state estimation,and a new sliding surface equation is *** ameliorated control algorithm exhibits good performance and can effectively suppress sliding mode control(SMC)*** and experimental results show that LQSMC offers high control precision,much stronger antiinterference,and robustness,which can effectively improve the positioning and tracking accuracy of a pressure control system compared with linear quadratic optimal control(LQC).The winding pressure control precision is improved by 45%to 50%.The results show that the porosity of composite fiber tape winding products decreased thanks to our method.

关键词： Composites tape winding Dynamics modeling Kalman filter LQSMC Pressure control

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Direct electrodeposition of ionic liquid-based template-free Sn Co alloy nanowires as an anode for Li-ion batteries

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International Journal of minerals,Metallurgy and Materials 2018年第9期25卷 1027-1034页

作者： Le-ping Wang Gang Chen qi-xin Shen Guo-min Li shi-you Guan Bing Li School of Materials science and Engineering East China University of Science and Technology Institute for Sustainable Energy Shanghai University

Sn Co alloy nanowires were successfully electrodeposited from Sn Cl2-Co Cl2-1-ethyl-3-methylimidazolium chloride(EMIC) ionic liquid without a template. The nanowires were obtained from the molar ratio of 5:40:60 for Sn Cl2(25)Co Cl2(25)EMIC at-0.55 V and showed a minimum diameter of about 50 nm and lengths of over 20 μm. The as-fabricated SnCo nanowires were about 70 nm in diameter and featured a Sn/Co weight ratio of 3.85:1, when used as an anode for a Li-ion battery, they presented respective specific capacities of 687 and 678 m Ah·g^(-1) after the first charge and discharge cycle and maintained capacities of about 654 m Ah·g^(-1) after 60 cycles and 539 m Ah·g^(-1) after 80 cycles at a current density of 300 m A·g^(-1). Both the nanowire structure and presence of elemental Co helped buffer large volume changes in the Sn anode during charging and discharging to a certain extent, thereby improving the cycling performance of the Sn anode.

关键词： SnCo alloy nanowires template electrodeposition ionic liquid

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Effects of Sm Co-doping on Luminescent Properties of Sr4Al14O25:M (M=Mn4+, Cr3+) Phosphors

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Chinese Journal of Chemical Physics 2015年第6期28卷 -页

作者： Yu-dong Xu Xu-dong Peng Lei Wang min shi Yuan Zhang Quan Wang San qi School of Materials Science and Engineering Hefei University of Technology Hefei 230009 China

The Sr4Al14O25:M and doped Sr4Al14O25:M+Sm3+ (M=Mn4+, Cr3+) phosphors were synthesized by a solid-state reaction method and their luminescent properties were investigated. The results showed that the co-doping of Sm ions did not change the positions of excitation band and emission band but significantly improved the luminescent properties of Sr4Al14O25:Cr3+phosphors; whereas, the emission intensity of Sr4Al14O25:Mn4+ was reduced remarkably when Sm ions were co-doped. In addtion, a radiative-form energy transfer from Sm3+ to Cr3+ was observed for the first time in the Cr, Sm co-doped Sr4Al14O25phosphors. The results indicated that Sm ions could significantly improve the emission intensity of Sr4Al14O25:Cr3+, making the Sm3+co-doped Sr4Al14O25:Cr3+phosphor a promising candidate for the applications in display and solid state lightening.

关键词： Phosphor Co-doping Strontium aluminates Energy transfer

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