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The relationship between interannual dry/wet changes and nomadic wars in the Hexi Corridor region of China during the period 241–1912 A.D.

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Science China Earth Sciences 2024年第6期67卷 1922-1931页

作者： Fei TANG Zhilin SHI Qinhua TIAN xiaogang DU Yong ZHANG Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Institute of Dunhuang Studies Lanzhou UniversityLanzhou 730020China National Climate Center China Meteorological AdministrationBeijing 100081China Longchanghe Station Gansu Qilian Mountain National Nature ReserveZhangye 734400China University of Chinese Academy of Sciences Beijing 100049China

The link between climate and war has long been a topic of great scientific and social *** this study,we investigate the influence of climate on warfare in China’s Hexi Corridor region since 241 *** the superposed epoch analysis of tree-ring data and historical war data,we observe a notable correlation between interannual dry-wet variations and wars instigated by nomadic groups in the Hexi ***,this relationship is dynamic and influenced by the region’s relative *** periods in which the Hexi Corridor was ruled by multiple regimes,wars tended to follow dry climatic conditions,which may be due to the fact that unusual drought during these periods likely heightened competition for resources and ***,during times of regional unity,wars were more likely to occur when climatic conditions were wet because the expansion of rangelands and the accumulation of resources helped fuel the nomads’outward *** findings underscore the complexity of the relationship between war and climate *** gain a more comprehensive understanding of this relationship,continuous,high-resolution historical temperature and humidity datasets with broader and more uniform coverage are needed across multiple *** addition,collecting and examining disaggregated historical war data for regions with distinct characteristics is essential.

关键词： Drought Interannual dry and wet variations War The Hexi Corridor Tree ring Nomadic groups

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Ligand-controlled electrochemiluminescence generation from CdSe/CdS/ZnS core/shell/shell quantum dots

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Nano Research 2024年第8期17卷 7776-7785页

作者： Hui Sun Zhiyuan Cao Haiyan Qin xiaogang Peng Bin Su Key Laboratory of Excited-State Materials of Zhejiang Province Department of ChemistryZhejiang UniversityHangzhou 310058China

The CdSe/CdS/ZnS core/shell/shell quantum dots(QDs)with strong exciton confinement have manifested themselves as competitive light-emitting materials in electrochemiluminescence(ECL).However,cathodic ECL generation by these QDs requires the injection of electron and hole from solid electrode and electrogenerated radicals(for example SO_(4)•^(−)),which is inevitably influenced by not only the inorganic structure of QDs but also the organic ligands on the *** this work we aimed at studying the impact of surface organic ligands on ECL performance of CdSe/CdS/ZnS *** changing the surface ligand from oleate to acetate,we phenomenologically observed the positive shift of ECL onset potential by ca.200 mV and the increase of ECL intensity by~100 times,suggesting that a short ligand is more favorable for ECL *** further comprehend the ligand effect,we measured the charge injection kinetics using potential-modulated,time-resolved photoluminescence,and thinlayer spectroelectrochemistry *** electron and hole injection into QDs were found to be accelerated by 2–20 times if shortening the ligand from oleate to acetate,confirming the significant impact of surface ligands on ECL performance of *** study is expected to provide guidance on how to design surface functionalized QDs for specific applications such as ECL immunodiagnosis,photocatalysis,and photovoltaics.

关键词： electrochemiluminescence quantum dots spectroelectrochemistry surface ligands charge injection charge transfer

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Monocular Distance Estimated Based on PTZ Camera

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Computers, Materials & Continua 2024年第5期79卷 3417-3433页

作者： Qirui Zhong xiaogang Cheng Yuxin Song Han Wang Bell Honors School Nanjing University of Posts and Telecommunications Nanjing210003China College of Telecommunications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing210003China College of Automation and College of Artificial Intelligence Nanjing University of Posts and TelecommunicationsNanjing210003China

This paper introduces an intelligent computational approach for extracting salient objects fromimages and estimatingtheir distance information with PTZ (Pan-Tilt-Zoom) cameras. PTZ cameras have found wide applications innumerous public places, serving various purposes such as public securitymanagement, natural disastermonitoring,and crisis alarms, particularly with the rapid development of Artificial Intelligence and global infrastructuralprojects. In this paper, we combine Gauss optical principles with the PTZ camera’s capabilities of horizontal andpitch rotation, as well as optical zoom, to estimate the distance of the *** present a novel monocular objectdistance estimation model based on the Focal Length-Target Pixel Size (FLTPS) relationship, achieving an accuracyrate of over 95% for objects within a 5 km range. The salient object extraction is achieved through a simplifiedconvolution kernel and the utilization of the object’s RGB features, which offer significantly faster computingspeeds compared to Convolutional Neural Networks (CNNs). Additionally, we introduce the dark channel beforethe fog removal algorithm, resulting in a 20 dB increase in image definition, which significantly benefits distanceestimation. Our system offers the advantages of stability and low device load, making it an asset for public securityaffairs and providing a reference point for future developments in surveillance hardware.

关键词： Public security location information PTZ camera image processing

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浙江地名“金华”并非源于“金星与婺女争华”

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中国历史地理论丛 2023年第4期38卷 155-159页

作者：金晓刚浙江师范大学人文学院浙江金华321004

浙江金华的得名,并非源于《玉台新咏·序》中的“金星与婺女争华”。南宋祝穆《方舆胜览》最早将二者相联系,是出于此书备载诗文以供览胜的需要。因《方舆胜览》的广泛影响,以及这一解释的美好寓意,遂广为后人接受。金华地名,实得名于... 详细信息

浙江金华的得名,并非源于《玉台新咏·序》中的“金星与婺女争华”。南宋祝穆《方舆胜览》最早将二者相联系,是出于此书备载诗文以供览胜的需要。因《方舆胜览》的广泛影响,以及这一解释的美好寓意,遂广为后人接受。金华地名,实得名于当地的金华山。而金华山之得名,则与道教有着密切渊源。

关键词：金华金华山 “金星与婺女争华” 道教

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Enhancing electrochemical capacity and interfacial stability of lithium-ion batteries through side reaction modulation with ultrathin carbon nanotube film and optimized lithium cobalt oxide particle size

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Nano Research 2024年第8期17卷 7230-7241页

作者： Wei Xi xiaogang Xia Jiacheng Zhu Dehua Yang Sishen Xie Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Advanced Passivation Technology Lab College of Physics Science and TechnologyHebei UniversityBaoding 071002China

Lithium cobalt oxide(LCO),the first commercialized cathode active material for lithium-ion batteries,is known for high voltage and ***,its application has been limited by relatively low capacity and stability at high *** particle size is considered one of the most straightforward and effective strategies to enhance ion transfer,thus increasing the rate ***,side reactions are simultaneously enhanced as the specific surface area ***,we investigate the impact of LCO particles with varying size distributions and optimize the particle *** modulate the side reactions associated with particle size reduction,an ultrathin carbon nanotube film(UCNF)is introduced to coat the cathode *** this simple process and optimized particle size,the rate performance improves significantly,normal commercial LCO achieves 118 mA·h·g^(−1)at 3.0–4.3 V and 20 C(0.72 mA·h·cm^(−2)),corresponding to power density of 8732 W·kg^(−1).This method is applied to high voltage as well,152 mA·h·g^(−1)at 3.0–4.6 V and 20 C(0.99 mA·h·cm^(−2))was achieved with high-voltage LCO(HVLCO),corresponding to power density of 11,552 W·kg^(−1).The cycling stability is also enhanced,with the capacity retention maintaining more than 96%after 100 cycles at 0.1 *** the first time,UCNF is demonstrated to suppress the excessive decomposition of the electrolytes and solvents by blocking electron injection/extraction between LCO and electrolyte *** findings provide a simple method for improving LCO rate performance,especially at high C-rates.

关键词： lithium-ion batteries lithium cobalt oxides carbon nanomaterials side reactions

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Special issue on electrochemical conversion and utilization of hydrogen energy

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Frontiers in Energy 2024年第3期18卷 263-264页

作者： Yun ZHENG Bo YU xiaogang FU Jiujun ZHANG Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China State Key Laboratory of Solidification Processing Atomic Control&Catalysis Engineering LaboratorySchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China

The concerns over energy crisis and climate change caused by the excessive consumption of fossil fuels and the associated emission of greenhouse gases, have driven many countries to develop policies for an energy transition into zero-carbon energy sources, essentially aiming at decarbonizing their energy systems. Among various renewable sources, hydrogen has been hailed as an ideal alternative to provide secure, cost-effective, and non-polluting energy. In recent years, there has been noteworthy progress in hydrogen electrochemical conversion and utilization techniques and devices, including water electrolyzers, proton-exchange membrane fuel cells (PEMFCs), solid oxide fuel cells (SOFCs), etc. Each of these technologies has yielded a series of encouraging advances. To showcase these recent advances, Frontiers in Energy is launching a special issue titled “electrochemical conversion and utilization of hydrogen energy”.

关键词： hydrogen energy. electrochemical

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特殊服装面料渲染算法

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计算机辅助设计与图形学学报 2023年第6期35卷 830-838页

作者：朱浩栋刘郴金小刚浙江大学CAD&CG国家重点实验室杭州310058

服装数字化是近年来服装行业发展的方向之一.服装面料的材质极其多样,然而常用的基于物理的渲染存在较大的局限性.基于此,提出对于多种不同特殊光学特性的面料渲染算法.其中,特殊面料是内嵌金属丝面料、侧光织物面料、镭射面料和闪粉面... 详细信息

服装数字化是近年来服装行业发展的方向之一.服装面料的材质极其多样,然而常用的基于物理的渲染存在较大的局限性.基于此,提出对于多种不同特殊光学特性的面料渲染算法.其中,特殊面料是内嵌金属丝面料、侧光织物面料、镭射面料和闪粉面料4种面料.针对内嵌金属丝面料,使用额外的纹理数据来记录并模拟金属丝的形状;针对侧光织物面料,根据视线方向以及入射方向与法线的夹角修正散射光的强度,使得面料拥有更加真实的侧面光感;针对镭射面料,将观察角与一种额外的镭射颜色相关联,并将其与原有的纹理颜色融合;针对闪粉面料,提出一种计算模型用于随机生成闪粉的位置,通过网格划分的方式达到实时的计算效率.将所提算法渲染结果与实际拍摄结果进行对比的结果表明,该算法的结果接近于真实;侧光织物面料和镭射面料已经被商业应用于国产三维服装设计软件Style3D中.

关键词：实时渲染特殊材质渲染各向异性渲染面料渲染

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三次B样条曲线骨架卷积曲面造型

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计算机辅助设计与图形学学报 2006年第9期18卷 1300-1305页

作者：张海林金小刚冯结青浙江大学CAD&CG国家重点实验室杭州310027

提出一种基于B样条曲线降阶的三次B样条曲线骨架卷积曲面造型方法.首先通过顶点扰动降阶方法把三次B样条曲线骨架(C1连续)降阶为C1连续的二次B样条,然后应用二次B样条曲线骨架的卷积曲面势函数计算方法得到三次B样条曲线骨架的势函数.

关键词：卷积曲面隐式曲面降阶几何造型

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A Residual Frequency Offset Estimation Method Based on Range Migration Fitting

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Journal of Beijing Institute of Technology 2024年第2期33卷 103-110页

作者： Liting Zhang Hao Huan Ran Tao xiaogang Tang School of Information and Electronics Beijing Institute of Technology School of Aerospace Information Space Engineering University

Recently, researchers have proposed an emitter localization method based on passive synthetic aperture. However, the unknown residual frequency offset(RFO) between the transmitter and the receiver causes the received Doppler signal to shift, which affects the localization accuracy. To solve this issue, this paper proposes a RFO estimation method based on range migration fitting. Due to the high frequency modulation slope of the linear frequency modulation(LFM)-modulation radar signal, it is not affected by RFO in range compression. Therefore, the azimuth time can be estimated by fitting the peak value position of the pulse compression in range ***, the matched filters are designed under different RFOs. When the zero-Doppler time obtained by the matched filters is consistent with the estimated azimuth time, the given RFO is the real RFO between the transceivers. The simulation results show that the estimation error of azimuth distance does not exceed 20 m when the received signal duration is not less than 3 s, the pulse repetition frequency(PRF) of the transmitter radar signal is not less than 1 k Hz, the range detection is not larger than 1 000 km, and the signal noise ratio(SNR) is not less than –5 d B.

关键词： range migration fitting (RMF) passive localization residual frequency offset (RFO)

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Enhancing Tropical Cyclone Intensity Estimation from Satellite Imagery through Deep Learning Techniques

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Journal of Meteorological Research 2024年第4期38卷 652-663页

作者： Wen YANG Jianfang FEI xiaogang HUANG Juli DING Xiaoping CHENG College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410008 Beijing Institute of Applied Meteorology Beijing 100029

This study first utilizes four well-performing pre-trained convolutional neural networks(CNNs) to gauge the intensity of tropical cyclones(TCs) using geostationary satellite infrared(IR) *** models are trained and tested on TC cases spanning from 2004 to 2022 over the western North Pacific *** enhance the models performance,various techniques are employed,including fine-tuning the original CNN models,introducing rotation augmentation to the initial dataset,temporal enhancement via sequential imagery,integrating auxiliary physical information,and adjusting *** optimized CNN model,i.e.,visual geometry group network(VGGNet),for TC intensity estimation is ultimately *** applied to the test data,the model achieves a relatively low mean absolute error(MAE) of 4.05 m s~(-1).To improve the interpretability of the model,the SmoothGrad combined with the Integrated Gradients approach is *** analyses reveal that the VGGNet model places significant emphasis on the distinct inner core region of a TC when estimating its ***,it partly takes into account the configuration of cloud systems as input features for the model,aligning well with meteorological *** several improvements made to this model's performance offer valuable insights for enhancing TC intensity forecasts through deep learning.

关键词： tropical cyclone intensity deep learning satellite imagery

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