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Global Solvability for a Predator-Prey Model with Prey-Taxis and Rotational Flux Terms

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 297-318页

作者： Guoqiang REN bin LIU School of Mathematics and Statistics Huazhong University of Science and Technology Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong Universityof Science and Technology

In this paper the author investigates the following predator-prey model with prey-taxis and rotational?ux terms■in a bounded domain with smooth *** presents the global existence of generalized solutions to the model... 详细信息

关键词： Predator-prey Prey-taxis Giopal existence Kotational flnux

Comprehensive Assessment of STGSA Generated Skeletal Mechanism for the Application in Flame-Wall Interaction and Flame-Flow Interaction

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Journal of Thermal Science 2024年第5期33卷 1946-1960页

作者： YU Chunkan YANG bin Institute of Technical Thermodynamics Karlsruhe Institute of TechnologyKarlsruhe 76131Germany Center for Combustion Energy Tsinghua UniversityBeijing 100084China

In this study,we conduct a thorough evaluation of the STGSA-generated skeletal mechanism for C_(2)H_4/*** STGSA-reduced mechanisms are taken into account,incorporating basic combustion models such as the homogeneous reactor model,one-dimensional flat premixed flame,and non-premixed counterflow ***,these models are applied to more complex combustion systems,considering factors like flame-flow interaction and flame-wall *** considerations take into account additional physical parameters and processes such as mixing frequency and *** results indicate that the skeletal mechanism adeptly captures the behavior of these complex combustion ***,it is suggested to incorporate strain rate considerations in generating the skeletal mechanism,especially when the combustion system operates under high turbulent intensity.

关键词： Species-Targeted Global Sensitivity Analysis(STGSA) mechanism reduction Partially Stirred Reactor(PaSR) spark ignition Head-on Quenching(HoQ)

A Real-Time Small Target Vehicle detection Algorithm with an Improved YOLOv5m Network Model

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Computers, Materials & Continua 2024年第1期78卷 303-327页

作者： Yaoyao du Xiangkui Jiang School of Automation Xi’an University of Posts and TelecommunicationsXi’an710121China

To address the challenges of high complexity,poor real-time performance,and low detection rates for small target vehicles in existing vehicle object detection algorithms,this paper proposes a real-time lightweight architecture based on You Only Look Once(YOLO)***,a lightweight upsampling operator called Content-Aware Reassembly of Features(CARAFE)is introduced in the feature fusion layer of the network to maximize the extraction of deep-level features for small target vehicles,reducing the missed detection rate and false detection ***,a new prediction layer for tiny targets is added,and the feature fusion network is redesigned to enhance the detection capability for small ***,this paper applies L1 regularization to train the improved network,followed by pruning and fine-tuning operations to remove redundant channels,reducing computational and parameter complexity and enhancing the detection efficiency of the *** is conducted on the VisDrone2019-deT *** experimental results show that the proposed algorithmreduces parameters and computation by 63.8% and 65.8%,*** average detection accuracy improves by 5.15%,and the detection speed reaches 47 images per second,satisfying real-time *** with existing approaches,including YOLOv5m and classical vehicle detection algorithms,our method achieves higher accuracy and faster speed for real-time detection of small target vehicles in edge computing.

关键词： Vehicle detection YOLOv5m small target channel pruning CARAFE

U-Net Models for Representing Wind Stress Anomalies over the Tropical Pacific and Their Integrations with an Intermediate Coupled Model for ENSO Studies

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Advances in Atmospheric Sciences 2024年第7期41卷 1403-1416页

作者： Shuangying du Rong-Hua Zhang Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao266071China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China Laosan Laboratory Qingdao266237China University of Chinese Academy of Sciences Beijing100049China

El Niño-Southern Oscillation(ENSO)is the strongest interannual climate mode influencing the coupled ocean-atmosphere system in the tropical Pacific,and numerous dynamical and statistical models have been developed to simulate and predict *** some simplified coupled ocean-atmosphere models,the relationship between sea surface temperature(SST)anomalies and wind stress(τ)anomalies can be constructed by statistical methods,such as singular value decomposition(SVD).In recent years,the applications of artificial intelligence(AI)to climate modeling have shown promising prospects,and the integrations of AI-based models with dynamical models are active areas of *** study constructs U-Net models for representing the relationship between SSTAs andτanomalies in the tropical Pacific;the UNet-derivedτmodel,denoted asτUNet,is then used to replace the original SVD-basedτmodel of an intermediate coupled model(ICM),forming a newly AI-integrated ICM,referred to as *** simulation results obtained from ICM-UNet demonstrate their ability to represent the spatiotemporal variability of oceanic and atmospheric anomaly fields in the equatorial *** the ocean-only case study,theτUNet-derived wind stress anomaly fields are used to force the ocean component of the ICM,the results of which also indicate reasonable simulations of typical ENSO *** results demonstrate the feasibility of integrating an AI-derived model with a physics-based dynamical model for ENSO modeling ***,the successful integration of the dynamical ocean models with the AI-based atmospheric wind model provides a novel approach to ocean-atmosphere interaction modeling studies.

关键词： U-Net models wind stress anomalies ICM integration of AI and physical components

Effects of Bisphenol A and Its Substitute, Bisphenol F, on the Gut Microbiota in Mice

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Biomedical and Environmental Sciences 2024年第1期37卷 19-30页

作者： MENG Li Ying TAO Wen Fu LI Jing ZHU Min ZHONG de bin ZHOU Jing QIN Xue WEI Rong Guo department of Clinical Laboratory The First Affiliated Hospital of Guangxi Medical UniversityNanning 530021GuangxiChina department of Clinical Laboratory The Fifth Affiliated Hospital of Guangxi Medical UniversityNanning 530021GuangxiChina Jiangsu Key Laboratory of Environmental Engineering Jiangsu Academy of Environmental SciencesNanjing 210000JiangsuChina

Objective The aim of this study was to assess the impact of bisphenol A(BPA)and its substitute,bisphenol F(BPF),on the colonic fecal community structure and function of *** We exposed 6–8-week-old male C57BL/6 mice to 5 mg/(kg∙day)and 50μg/(kg∙day)of BPA or BPF for 14 *** samples from the colon were analyzed using 16S rRNA *** Gut microbiome community richness and diversity,species composition,and function were significantly altered in mice exposed to BPA or *** change was characterized by elevated levels of Ruminococcaceae UCG-010 and Oscillibacter and decreased levels of Prevotella 9 and ***,pathways related to carbohydrate and amino acid metabolism showed substantial *** Mice exposed to different BP analogs exhibited distinct gut bacterial community richness,composition,and related metabolic *** the essential role of gut bacteria in maintaining intestinal homeostasis,our study highlights the intestinal toxicity of BPs in vertebrates.

关键词： Bisphenol A(BPA) Bisphenol F(BPF) 16S rRNA Microbiota

跨国公司研发全球化的空间等级体系研究--基于因子分析的结果

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世界地理研究 2008年第1期17卷 85-93页

作者：祝影杜德斌上海大学国际工商与管理学院公共管理系上海201800 华东师范大学城市与区域经济系上海200062

在公司区位选择研究的基础上探索跨国公司研发全球化的空间等级体系,是地理学对跨国公司研发全球化研究的有益尝试。跨国公司研发全球化是多种因素协同互动的结果,为了相对科学直观地构建跨国公司全球研发空间等级体系,本文运用因子分... 详细信息

在公司区位选择研究的基础上探索跨国公司研发全球化的空间等级体系,是地理学对跨国公司研发全球化研究的有益尝试。跨国公司研发全球化是多种因素协同互动的结果,为了相对科学直观地构建跨国公司全球研发空间等级体系,本文运用因子分析方法对84个样本进行研究表明,跨国公司全球研发网络是多种因素协同互动的结果,综合实力、研发环境、市场规模是其中最重要的区位因子。根据因子分析的综合得分,将跨国公司研发全球化的空间等级分为五个层次,即核心区域、高密区域、中密区域、低密区域和弱势区域,发达国家明显占据全球研发空间体系的主导地位,掌控着科技发展前沿和关键核心技术,但个别发展中国家和地区也已进入较高层次。根据各主因子的得分情况,按照在全球位势强弱和要素空间流向的不同,把全球国家(地区)分为全面发展型、环境优势型和市场潜力型三种类型。其中,中国位列跨国公司研发全球化的高密区域,但仍属市场潜力型国家,处于接受扩散的境地,基础研究和创新能力薄弱以及内外向流动的不均衡,阻碍了跨国公司全球研发空间体系节点区域的创建。

关键词：空间等级体系研发全球化跨国公司因子分析

Study on the tribological properties of metal rolling bearing under lubrication with diketone lubricants

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Science China(Technological Sciences) 2024年第7期67卷 2003-2017页

作者： du ShaoNan ZHANG ChenHui LUO Zhi State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Beijing National Laboratory of Molecular Sciences CAS Key Laboratory of Engineering PlasticsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

In this article, 1-(4-ethylphenyl)-nonane-1,3-dione(0206) was prepared by Claisen condensation. By mixing 0206, chelate, and base oil in a ratio of 3.2:4.8:2, a diketone lubricant(PAO=14(20%)) that can achieve superlubricity was prepared and applied to bearing lubrication experiments. The experimental results show that when the bearing was lubricated by base oil, the friction coefficient(COF) and temperature rise decreased with the decrease of the viscosity of PAO. When PAO=14(20%) was used as the lubricant, the COF of the bearing was the lowest(0.001), and the wear morphology was comparable to that of the bearing lubricated with commercial lubricant. Compared with the base oil with the same viscosity, it is found that the COF and temperature rise of the bearing lubricated by PAO=14(20%) were lower under any experimental conditions. And when the amount of lubricant added was 10 μL, the COF of the bearing lubricated by PAO=14(20%) reached a very low value(0.0004).Bearing ball surface analysis identified the formation of diketone adsorption films. Combined with the previous PAO=14(20%)superlubricity mechanism, it was considered that the occurrence of tribochemical reaction and the bearing effect of chelates were the main reasons for the existence of ultra-low friction coefficient and low wear. In addition, when there were polar molecules in the lubricant, they were adsorbed on the metal surface through tribochemical reactions, resulting in many irregular pits on the surface.

关键词： superlubricity diketone chelate tribochemical recations bearing lubrication

Visible-frequency nonvolatile reconfigurable Janus metasurfaces for dual-wavelength-switched and spin-asymmetric holograms

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Photonics Research 2024年第2期12卷 356-368页

作者： HUAN YUAN ZHEQIANG ZHONG bin ZHANG College of Electronics and Information Engineering Sichuan UniversityChengdu 610064China Big Data Analysis and Fusion Application Technology Engineering Laboratory of Sichuan Province Chengdu 610065China

Janus metasurface holography with asymmetric transmission characteristics provides new degrees of freedom for multiplexing ***,earlier metasurfaces with asymmetrical transmission faced limitations in terms of tunability and *** this study,we propose a metasurface color holographic encryption scheme with dynamic switching and asymmetric transmission at visible frequencies using a low-loss nonvolatile optical phase-change material,Sb_(2)S_(3).Using a modified holographic optimization strategy,we achieved highfidelity asymmetric holographic imaging of a nanostructured *** controlling the incident direction and wavelength of visible light,as well as the level of crystallization of Sb_(2)S_(3),this reconfigurable metasurface enables the precise manipulation of tunable color holographic image *** particular,in the semi-crystalline state of Sb_(2)S_(3),the encoded information can be securely encrypted using a two-channel color-holographic image,whereas only a preset camouflaged image is displayed in the crystalline or amorphous state of Sb_(2)S_(3).The proposed multiencrypted Janus metasurface provides a potential approach for dynamic holographic displays with ultrahigh capacity,holographic encryption,and information storage.

关键词： holographic asymmetric visible

Repair tolerance assessment for aircraft composite structures using Bayesian updating

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Chinese Journal of Aeronautics 2024年第6期37卷 360-391页

作者： Xin LI Hongfu ZUO bin YANG School of Automotive and Rail Transit Nanjing Institute of TechnologyNanjing 211167China Civil Aviation Key Laboratory of Aircraft Health Monitoring and Intelligent Maintenance College of Civil AviationNanjing University of Aeronautics and AstronauticsNanjing 211106China

detection and repair of composite damage is crucial to ensure the safety and reliability of aircraft structures.A novel approach to quantitatively evaluate the repair tolerance of composite structures in civil aircraft based on Bayesian updating is *** method incorporates historical damage inspection data to determine the prior distribution of damage size,which is then updated with newly collected damage size data using Bayesian *** Carlo simulation is employed to investigate the probability of failure and estimate maintenance costs,considering various factors such as the frequency and timing of damage events,damage detection,structural strength,gust loads,and maintenance expenses throughout the lifecycle of composite *** and economic factors are considered to establish a lower threshold for repairs and an upper threshold for maintenance based on the occurrence of accidental impact *** of the effectiveness and feasibility of a quantitative assessment method for repair tolerance is conducted using damage statistics data from civil aircraft routes utilizing the structural skin panels of composite outer *** results demonstrate that the method proposed in conjunction with extensive simulations and full utilization of field damage inspection data can effectively simulate unexpected impact damage situations that may occur during civil aircraft service and evaluate the reliability and economic feasibility of the repair of *** research findings hold significant theoretical and practical value for the preparation of documents for continued airworthiness of composite structures,including structural repair manuals and maintenance programs.

关键词： Composite structures Repair tolerance Maintenance Bayesian updating Probability of failure