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Co-influence of the start of thermal growing season and precipitation on vegetation spring green-up on the Tibetan Plateau

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Advances in Climate Change Research 2024年第2期15卷 327-337页

作者： Chen-Peng WANG meng-tian huang Pan-Mao ZHAI State Key Laboratory of Severe Weather and Institute of Global Change and Polar Meteorology Chinese Academy of Meteorological SciencesBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China

The climate in the Tibetan Plateau(TP)has undergone significant change in recent decades,mainly in thermal and water conditions,which plays a crucial role in phenological changes in vegetation spring ***,how the start of the thermal growing season(SOS-T)and the start of the rainy season(SORS)as key climatic factors affect vegetation green-up remains *** that these factors characterize thermal and water conditions required for vegetation green-up,this study investigated changes in the SOS-T and SORS from 1961 to 2022,using observation-based datasets with long time *** found that the SOS-T and SORS have advanced across the TP in 1961-2022 and have shown a spatial pattern of advancement in the east and delay in the west in ***,the co-effect of temperature and precipitation change on the start of vegetation growing season(SOS-V)in 2000-2022 was *** across TP,the SOS-V had an early onset of 1.3 d per decade during 2000-2022,corresponding to advanced SOS-T and ***,the SOS-V generally occurred nearly at the same time as the SOS-T in the high-altitude meadow region.A substantial delay in the SOS-V relative to the SOS-T was observed in the desert,shrub,grassland and forest regions and generally kept pace with the ***,for 50%of the vegetated regions on the TP,inter-annual variation in the delay in the SOS-V relative to the SOS-T was dominated by precipitation change,which was profound in warm-climate *** study highlights the co-regulation of precipitation and temperature change in the SOS-V in different vegetation cover regions in the TP,offering a scientific foundation for comprehending the impact of climate change and prospects for vegetation phenology on the TP.

关键词： Tibetan Plateau Start of growing season Temperature Precipitation Climate change

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Transient Stability Analysis of Converter-based Islanded Microgrids Based on Iterative Equal Area Criterion Considering Reactive Power Loop Dynamics and Varying Damping

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1170-1182页

作者： Xilin Li Jingyi Zhang Zhen tian Xiaoming Zha Wei Wang meng huang Chong Shao Hubei Key Laboratory of Power Equipment&System Security for Integrated Energy School of Electrical Engineering and AutomationWuhan UniversityWuhanChina NARI Technology Co. Ltd.NanjingChina State Grid Gansu Electric Power Company LanzhouChina

With the rapid increase in the installed capacity of renewable energy in modern power systems,the stable operation of power systems with considerable power electronic equipment requires further *** converter-based islanded mi-crogrid(CIM)systems equipped with grid-following(GFL)and grid-forming(GFM)voltage-source converters(VSCs),it is chal-lenging to maintain stability due to the mutual coupling effects between different VSCs and the loss of voltage and frequency sup-port from the power *** previous studies,quantitative transient stability analysis was primarily used to assess the active power loop of ***,frequency and voltage dy-namics are found to be strongly coupled,which strongly affects the estimation result of stability *** addition,the vary-ing damping terms have not been fully *** bridge these gaps,this paper investigates the transient stability of CIM consid-ering reactive power loop dynamics and varying ***,an accuracy-enhanced nonlinear model of the CIM is derived based on the effects of reactive power loop and post-disturbance frequency jump *** these effects will elimi-nates the risk of *** reactive power loop dynamics make the model coefficients be no longer constant and thus vary with the power *** evaluate quantitatively the effects of re-active power loop and varying damping on the transient stability of CIM,an iterative criterion based on the equal area criterion theory is *** addition,the effects of parameters on the stable boundary of power system are analyzed,and the dynamic interaction mechanisms are *** and experiment results verify the merits of the proposed method.

关键词： Transient stability converter iterative criterion reactive power loop post-disturbance frequency jump

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First wetland mapping at 10-m spatial resolution in South America using multi-source and multi-feature remote sensing data

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Science China Earth Sciences 2024年第10期67卷 3252-3269页

作者： Weiwei SUN Gang YANG Yuling huang Dehua MAO Ke huang Lin ZHU Xiangchao meng tian FENG Chao CHEN Yong GE Department of Geography and Spatial Information Techniques Ningbo UniversityNingbo 315211China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences&Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Natural Resources and Planning Bureau Shanghai Pudong New DistrictShanghai 200100China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China Faculty of Electrical Engineering and Computer Science Ningbo UniversityNingbo 315211China School of Geography Science and Geomatics Engineering Suzhou University of Science and TechnologySuzhou 215009China

Wetland degradation has been accelerating in recent years globally. Accurate information on the geographic distribution and categories of wetlands is essential for their conservation and management. Despite being the world′s fourth largest continent, South America has limited research on wetland mapping, and there is currently no available map that provides comprehensive information on wetland distribution and categories in the region. To address this issue, we used Sentinel-1, Sentinel-2 and SRTM data, developed a sample collection method and a wetland mapping method with a collection of multi-source features such as optical features, polarization features and shape features for South American wetlands. We produced a 10-m resolution wetland map based on the Google Earth Engine(GEE) platform. Our Level-1 wetland cover map accurately captured six wetland sub-categories with an overall accuracy of 96.24% and a kappa coefficient of 0.8649, while our Level-2 water cover map included five sub-categories with an overall accuracy of 97.23% and a kappa coefficient of0.9368. The results show that the total area of existing wetlands in South America is approximately 1,737,000 km~2, which is6.8% of the total land area. Among the ten wetland categories, shallow sea had the largest area(960,527.4 km~2), while aquaculture ponds had the smallest area 1513.6 km~2. Swamp had the second largest area(306,240.1 km~2). Brazil, Argentina,Venezuela, Bolivia, and Colombia were found to have the largest wetland areas, with Brazil and Colombia having the most diverse wetland categories. This product can serve as baseline data for subsequent monitoring, management, and conservation of South American wetlands.

关键词： Wetland mapping Google Earth Engine Sentinel imagery South America

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Recent progress in side chain engineering of Y-series non-fullerene molecule and polymer acceptors

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Science China Chemistry 2024年第3期67卷 788-805页

作者： Li tian Chunchen Liu Fei huang School of Materials Science and Engineering Henan University of TechnologyZhengzhou 450001China Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and DevicesSouth China University of TechnologyGuangzhou 510640China

Organic solar cells(OSCs) have drawn considerable attention in the last decade due to the great potential of light weight,flexibility, and low-cost solution processing. Particularly, Y-series non-fullerene acceptors(NFAs) including small molecular acceptors(SMAs) and polymerized small molecular acceptors(PSMAs) have become research hot spots due to their excellent power conversion efficiency. Side chain engineering is crucial to adjust the solubility and crystallinity of NFAs, which will significantly affect the morphology of active layers and the efficiency of OSCs. However, the understanding of side chain engineering on NFAs is still limited and lacks a systematic review. This review aims to provide a brief summary of the recent developments in side chain engineering of NFAs, with a special focus on the design and application of Y-series SMAs and PSMAs for high-efficiency non-fullerene organic solar cells(NF-OSCs). In addition, the review also points out challenges and provides useful guidance regarding side chain regulation for Y-series NFAs.

关键词： organic solar cell Y-series non-fullerene acceptors side chain engineering

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Stable multi-electron reaction stimulated by W doping VS_(4)for enhancing magnesium storage performance

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Journal of Energy Chemistry 2024年第2期89卷 89-98,I0004页

作者： Yuxin tian Jiankang Chen Guofeng Wang Bing Sun Alan meng Lei Wang Guicun Li Jianfeng huang Shiqi Ding Zhenjiang Li College of Materials Science and Engineering Qingdao University of Science and TechnologyQingdao 266042ShandongChina Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science MOEShandong Key Laboratory of Biochemical AnalysisCollege of Chemistry and Molecular EngineeringQingdao University of Science and TechnologyQingdao 266042ShandongChina School of Material Science and Engineering International S&T Cooperation Foundation of Shaanxi ProvinceXi’an Key Laboratory of Green Manufacture of Ceramic MaterialsShaanxi University of Science and TechnologyXi’an 710021ShaanxiChina

Rechargeable magnesium batteries(RMBs)hold promise for offering higher volumetric energy density and safety features,attracting increasing research interest as the next post lithium-ion *** high performance cathode material by inducing multi-electron reaction process as well as maintaining structural stability is the key to the development and application of ***,multielectron reaction occurred in VS_(4)by simple W doping strategy.W doping induces valence of partial V as V^(2+)and V^(3+)in VS_(4)structure,and then stimulates electrochemical reaction involving multi-electrons in 0.5%*** flower-like microsphere morphology as well as rich S vacancies is also modulated by W doping to neutralize structure change in such multi-electron reaction *** fabricated 0.5%W-V-S delivers higher specific capacity(149.3 m A h g^(-1)at 50 m A g^(-1),which is 1.6 times higher than that of VS_(4)),superior rate capability(76 mA h g^(-1)at 1000 mA g^(-1)),and stable cycling performance(1500cycles with capacity retention ratio of 93.8%).Besides that,pesudocapaticance-like contribution analysis as well as galvanostatic intermittent titration technique(GITT)further confirms the enhanced Mg^(2+)storage kinetics during such multi-electron involved electrochemical reaction *** discovery provides new insights into the designing of multi-electron reaction process in cathode as well as neutralizing structural change during such reaction for realizing superior electrochemical performance in energy storage devices.

关键词： Multi-electron reaction W doping Stable structure Cathode Rechargeable magnesium batteries

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3D printing in space:from mechanical structures to living tissues

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International Journal of Extreme Manufacturing 2024年第2期6卷 378-387页

作者： Mao Mao Zijie meng Xinxin huang Hui Zhu Lei Wang Xiaoyong tian Jiankang He Dichen Li Bingheng Lu State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China National Medical Products Administration(NMPA)Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China National Innovation Platform(Center)for Industry-Education Integration of Medical Technology Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China Frontier Institute of Science and Technology Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China National Innovation Institute of Additive Manufacturing Xi’an 710000People’s Republic of China

3D printing stands at the forefront of transforming space exploration,offering unprecedented on-demand and rapid manufacturing *** adeptly addresses challenges such as mass reduction,intricate component fabrication,and resource *** the obstacles posed by microgravity and extreme environments,continual advancements underscore the pivotal role of 3D printing in aerospace *** its primary function of producing space structures,3D printing contributes significantly to progress in electronics,biomedicine,and resource *** perspective delves into the technological advantages,environmental challenges,development status,and opportunities of 3D printing in *** its crucial impact,we anticipate that 3D printing will unlock innovative solutions,reshape manufacturing practices,and foster self-sufficiency in future space endeavors.

关键词： 3D printing in space space manufacturing microgravity

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Modeling and analysis for material removal and surface roughness in fluid jet polishing of optical glass

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Friction 2024年第7期12卷 1548-1563页

作者： Zhongchen CAO Ming WANG Haitao LIU tian huang Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China School of Engineering The University of WarwickCoventry CV47ALUK

luid jet polishing(FJP)is a non-contact polishing technology that can fabricate free-form optical surfaces with sub-micron-level form accuracy and nano-level surface roughness,especially for hard and brittle *** surface generation model of FJP can be used to guide the determination and optimization of process parameters and is of great significance for understanding the evolution mechanism of surface ***,predictive models for the microscopic topography of polished surfaces are still *** study established a macroscopic surface profile model for predicting 3D material removal characteristics and surface texture by combining the 3D computer fluid dynamics(CFD)simulation model and single-particle erosion mechanism.A fractal theory-based erosion model has been built to calculate the material removal caused by the erosion of a single abrasive particle on the rough surface;thus,it predicts the micro-topography and surface roughness of the polished samples.A series of polishing experiments were conducted to analyze the feasibility and accuracy of the model quantitatively and study the influence mechanism of process parameters on the material removal characteristics and surface *** indicated that the models could well predict material removal and surface *** prediction accuracy of the surface roughness Ra and maximum removal depth is better than 91.6%and 90%,*** is also found that the material removal rate of FJP could reach 0.517 mm3/min,and the surface roughness convergence rate could reach 62.9%.

关键词： fluid jet polishing(FJP) computational fluid dynamics(CFD) material removal mechanism surface roughness theoretical model

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Integrating Neighborhood Geographic Distribution and Social Structure Influence for Social Media User Geolocation

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2513-2532页

作者： meng Zhang Xiangyang Luo Ningbo huang Key Laboratory of Cyberspace Situation Awareness of Henan Province Zhengzhou450001China State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou450001China

Geolocating social media users aims to discover the real geographical locations of users from their publicly available data,which can support online location-based applications such as disaster alerts and local content *** relationship-based methods represent a classical approach for geolocating social ***,geographically proximate relationships are sparse and challenging to discern within social networks,thereby affecting the accuracy of user *** address this challenge,we propose user geolocation methods that integrate neighborhood geographical distribution and social structure influence(NGSI)to improve geolocation ***,we propose a method for evaluating the homophily of locations based on the k-order neighbor-hood geographic distribution(k-NGD)similarity among *** are notable differences in the distribution of k-NGD similarity between location-proximate and non-location-proximate *** this distinction,we filter out non-location-proximate social relationships to enhance location homophily in the social *** better utilize the location-proximate relationships in social networks,we propose a graph neural network algorithm based on the social structure *** algorithm enables us to perform a weighted aggregation of the information of users’multi-hop neighborhood,thereby mitigating the over-smoothing problem of user features and improving user geolocation *** results on real social media dataset demonstrate that the neighborhood geographical distribution similarity metric can effectively filter out non-location-proximate social ***,compared with 7 existing social relationship-based user positioning methods,our proposed method can achieve multi-granularity user geolocation and improve the accuracy by 4.84%to 13.28%.

关键词： User geolocation social media neighborhood geographic distribution structure influence

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A Study on Enhancing Chip Detection Efficiency Using the Lightweight Van-YOLOv8 Network

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Computers, Materials & Continua 2024年第4期79卷 531-547页

作者： meng huang Honglei Wei Xianyi Zhai School of Mechanical Engineering and Automation Dalian Polytechnic UniversityDalian116034China

In pursuit of cost-effective manufacturing,enterprises are increasingly adopting the practice of utilizing recycled semiconductor *** ensure consistent chip orientation during packaging,a circular marker on the front side is employed for pin alignment following successful functional ***,recycled chips often exhibit substantial surface wear,and the identification of the relatively small marker proves ***,the complexity of generic target detection algorithms hampers seamless *** these issues,this paper introduces a lightweight YOLOv8s-based network tailored for detecting markings on recycled chips,termed ***,to alleviate the influence of diminutive,low-resolution markings on the precision of deep learning models,we utilize an upscaling approach for enhanced *** technique relies on the Super-Resolution Generative Adversarial Network with Extended Training(SRGANext)network,facilitating the reconstruction of high-fidelity images that align with input ***,we replace the original YOLOv8smodel’s backbone feature extraction network with the lightweight VanillaNetwork(VanillaNet),simplifying the branch structure to reduce network ***,a Hybrid Attention Mechanism(HAM)is implemented to capture essential details from input images,improving feature representation while concurrently expediting model inference *** results demonstrate that the Van-YOLOv8 network outperforms the original YOLOv8s on a recycled chip dataset in various ***,it demonstrates superiority in parameter count,computational intricacy,precision in identifying targets,and speed when compared to certain prevalent algorithms in the current *** proposed approach proves promising for real-time detection of recycled chips in practical factory settings.

关键词： Lightweight neural networks attention mechanisms image super-resolution enhancement feature extraction small object detection

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In situ direct reprogramming of astrocytes to neurons via polypyrimidine tract-binding protein 1 knockdown in a mouse model of ischemic stroke

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Neural Regeneration Research 2024年第10期19卷 2240-2248页

作者： meng Yuan Yao Tang tianwen huang Lining Ke En huang Key Laboratory of Brain Aging and Neurodegenerative Diseases of Fujian Province Fujian Medical UniversityFuzhouFujian ProvinceChina Department of Human Anatomy School of Basic Medical SciencesFujian Medical UniversityFuzhouFujian ProvinceChina Scientific Research Center School of Basic Medical SciencesFujian Medical UniversityFuzhouFujian ProvinceChina Department of Neurology Fujian Medical University Union HospitalFuzhouFujian ProvinceChina Fujian Key Laboratory of Vascular Aging Fujian Medical UniversityFuzhouFujian ProvinceChina

In situ direct reprogramming technology can directly convert endogenous glial cells into functional neurons in vivo for central nervous system repair. Polypyrimidine tract-binding protein 1(PTB) knockdown has been shown to reprogram astrocytes to functional neurons in situ. In this study, we used AAV-PHP.e B-GFAP-sh PTB to knockdown PTB in a mouse model of ischemic stroke induced by endothelin-1, and investigated the effects of GFAP-sh PTB-mediated direct reprogramming to neurons. Our results showed that in the mouse model of ischemic stroke, PTB knockdown effectively reprogrammed GFAP-positive cells to neurons in ischemic foci, restored neural tissue structure, reduced inflammatory response, and improved behavioral function. These findings validate the effectiveness of in situ transdifferentiation of astrocytes, and suggest that the approach may be a promising strategy for stroke treatment.

关键词： astrocyte in situ direct reprogramming ischemic stroke miR-30 based shRNA neuron polypyrimidine tract-binding protein 1 transdifferentiation

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