检索结果-南通市图书馆

Impacts of central-Pacific El Niño and physical drivers on eastern Pacific bigeye tuna

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2024年第3期42卷 972-987页

Bigeye tuna Thunnus obesus is an important migratory species that forages deeply,and El Niño events highly influence its distribution in the eastern Pacific *** sea surface temperature is widely recognized as the main factor affecting bigeye tuna(BET)distribution during El Niño events,the roles of different types of El Niño and subsurface oceanic signals,such as ocean heat content and mixed layer depth,remain *** conducted A spatial-temporal analysis to investigate the relationship among BET distribution,El Niño events,and the underlying oceanic signals to address this knowledge *** used monthly purse seine fisheries data of BET in the eastern tropical Pacific Ocean(ETPO)from 1994 to 2012 and extracted the central-Pacific El Niño(CPEN)indices based on Niño 3 and Niño ***,we employed Explainable Artificial Intelligence(XAI)models to identify the main patterns and feature importance of the six environmental variables and used information flow analysis to determine the causality between the selected factors and BET ***,we analyzed Argo datasets to calculate the vertical,horizontal,and zonal mean temperature differences during CPEN and normal years to clarify the oceanic thermodynamic structure differences between the two types of *** findings reveal that BET distribution during the CPEN years is mainly driven by advection feedback of subsurface warmer thermal signals and vertically warmer habitats in the CPEN domain area,especially in high-yield fishing *** high frequency of CPEN events will likely lead to the westward shift of fisheries centers.

关键词： bigeye tuna central-Pacific El Niño(CPEN) ocean heat content Argo explainable artificial intelligence(XAI) information flow

Comparisons of Wave Force Model Effects on the Structural Responses and Fatigue Loads of a Semi-Submersible Floating Wind Turbine

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean university of China 2024年第1期23卷 69-79页

作者： HAN Yanqing le Conghuan ZHANG Puyang Xu Shengnan State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China School of Hydraulic Engineering Ludong UniversityYantai 264025China School of Civil Engineering Tianjin UniversityTianjin 300072China Shandong Marine Aerospace Equipment Technological Innovation Center Yantai 264004China

The selection of wave force models will significantly impact the structural responses of floating wind *** this study,comparisons of wave force model effects on the structural responses and fatigue loads of a semi-submersible floating wind turbine(SFWT)were *** were performed by employing the Morison equation(ME)with linear or second-order wave kinematics and potential flow theory(PFT)with first-or second-order wave forces.A comparison of regular waves,irregular waves,and coupled wind/waves analyses with the experimental data showed that many of the simulation results and experimental data are relatively ***,notable discrepancies are found in the response amplitude operators for platform heave,tower base bending moment,and tension in mooring *** models give more satisfactory results of heave but more significant discrepan-cies in tower base bending moment than the ME *** irregular wave analyses,low-frequency resonances were captured by PFT models with second-order difference-frequency terms,and high-frequency resonances were captured by the ME models or PFT models with second-order sum-frequency *** force models capture the response frequencies but do not reasonably predict the response *** coupled wind/waves analyses showed more satisfactory results than the wave-only ***,an important detail to note is that this satisfactory result is based on the overprediction of wind-induced responses.

关键词： floating wind turbine wave force model potential flow theory Morison equation second-order wave forces

Self-actuating protection mechanisms for safer lithium-ion batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第7期94卷 181-198页

作者： Yang Luo Chunchun Sang Kehan le Hao Chen Hui Li Xinping Ai Hubei Key Lab of Electrochemical Power Sources College of Chemistry&Molecular ScienceWuhan UniversityWuhan 430072HubeiChina state Key Laboratory of New Textile Materials&Advanced Processing Technologies Wuhan Textile UniversityWuhan 430200HubeiChina

Safety issue is still a problem nowadays for the large-scale application of lithium-ion batteries(LIBs)in electric vehicles and energy storage *** unsafe behaviors of LIBs arise from the thermal run-away,which is intrinsically triggered by the overcharging and *** improve the safety of LIBs,various protection strategies based on self-actuating reaction control mechanisms(SRCMs)have been proposed,including redox shuttle,polymerizable monomer additive,potential-sensitive separator,thermal shutdown separator,positive-temperature-coefficient electrode,thermally polymerizable addi-tive,and reversible thermal phase transition *** build-in protection mechanisms,these meth-ods can sensitively detect either the temperature change inside battery or the potential change of the electrode,and spontaneously shut down the electrode reaction at risky conditions,thus preventing the battery from going into thermal *** their advantages in enhancing the intrinsic safety of LIBs,this paper overviews the research progresses of SRCMs after a brief introduction of thermal runaway mechanism and limitations of conventional thermal runaway mitigating *** importantly,the current states and issues,key challenges,and future developing trends of SRCTs are also discussed and outlined from the viewpoint of practical application,aiming at providing insights and guidance for developing more effective SRCMs for LIBs.

关键词： Li-ion battery Safety Thermal runaway Thermal protection Overcharge protection

Sensitivity impacts owing to the variations in the type of zero-range pairing forces on the fission properties using the density functional theory

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第3期35卷 198-207页

作者： Yang Su Ze-Yu Li Li-le Liu Guo-Xiang Dong Xiao-Bao Wang Yong-Jing Chen China Nuclear Data Center China Institute of Atomic EnergyBeijing 102413China School of Science Huzhou UniversityHuzhou 313000China

using the Skyrme density functional theory,potential energy surfaces of^(240)Pu with constraints on the axial quadrupole and octupole deformations(q_(20)and q_(30))were *** volume-like and surface-like pairing forces,as well as a combination of these two forces,were used for the Hartree–Fock–Bogoliubov *** in the least-energy fission path,fission barrier,pairing energy,total kinetic energy,scission line,and mass distribution of the fission fragments based on the different forms of the pairing forces were analyzed and *** fission dynamics were studied based on the timedependent generator coordinate method plus the Gaussian overlap *** results demonstrated a sensitivity of the mass and charge distributions of the fission fragments on the form of the pairing *** on the investigation of the neutron-induced fission of^(239)Pu,among the volume,mixed,and surface pairing forces,the mixed pairing force presented a good reproduction of the experimental data.

关键词： Nuclear fission Density functional theory Pairing force Potential energy surfaces Fission fragment distribution

understanding and improving fairness in cognitive diagnosis

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第5期67卷 99-114页

作者： Zheng ZHANG le Wu Qi LIu Jiayu LIu Zhenya HuANG Yu YIN Yan ZHuANG Weibo GAO Enhong CHEN Anhui Province Key Laboratory of Big Data Analysis and Application School of Computer Science and Technology& School of Data Science University of Science and Technology of China State Key Laboratory of Cognitive Intelligence School of Computer Science and Information Engineering Hefei University of Technology

Intelligent education is a significant application of artificial intelligence. One of the key research topics in intelligence education is cognitive diagnosis, which aims to gauge the level of proficiency among students on specific knowledge concepts(e.g., Geometry). To the best of our knowledge, most of the existing cognitive models primarily focus on improving diagnostic accuracy while rarely considering fairness issues; for instance, the diagnosis of students may be affected by various sensitive attributes(e.g., region). In this paper,we aim to explore fairness in cognitive diagnosis and answer two questions:(1) Are the results of existing cognitive diagnosis models affected by sensitive attributes?(2) If yes, how can we mitigate the impact of sensitive attributes to ensure fair diagnosis results? To this end, we first empirically reveal that several wellknown cognitive diagnosis methods usually lead to unfair performances, and the trend of unfairness varies among different cognitive diagnosis models. Then, we make a theoretical analysis to explain the reasons behind this phenomenon. To resolve the unfairness problem in existing cognitive diagnosis models, we propose a general fairness-aware cognitive diagnosis framework, FairCD. Our fundamental principle involves eliminating the effect of sensitive attributes on student proficiency. To achieve this, we divide student proficiency in existing cognitive diagnosis models into two components: bias proficiency and fair *** design two orthogonal tasks for each of them to ensure that fairness in proficiency remains independent of sensitive attributes and take it as the final diagnosed result. Extensive experiments on the Program for International Student Assessment(PISA) dataset clearly show the effectiveness of our framework.

关键词： fairness intelligent education cognitive diagnosis psychometrics adversarial learning

An Analysis of the Fragmentation of Observing Time At the Muztagh-Ata Site

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第3期24卷 29-33页

作者： Wen-Bo Gu Jing Xu Guo-Jie Feng Xuan Zhang le-Tian Wang Xin-Liang Wang Ali Esamdin Li-Xian Shen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 83001lChina School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

Cloud cover plays a pivotal role in assessing observational conditions for astronomical *** for the fraction of observing time,its fragmentation also wields a significant influence on the quality of nighttime sky *** this article,we introduce the functionΓ∈[0,1],designed to comprehensively capture both the fraction of available observing time and its *** in situ measurement data gathered at the Muztagh-Ata site between 2017 and 2021,we showcase the effectiveness of our *** statistical result illustrates that the Muztagh-Ata site affords approximately 122 nights that were absolutely clear and 205 very good nights annually,corresponding toΓ≥0.9 andΓ≥0.36 respectively.

关键词： site testing-atmospheric effects-methods statistical

在线全文

学校读者我要写书评

暂无评论

改进多目标蜂群算法优化洗出运动及仿真实验

系统仿真学报 2024年第2期36卷 436-448页

作者：王辉彭乐中国民航大学航空工程学院天津300300

针对经典洗出算法参数选择不当导致信号缺失,引起失真,影响洗出效果等问题,提出一种改进的多目标人工蜂群算法,利用该算法对经典洗出算法中的滤波器参数进行优化来改善洗出算法的洗出效果。针对传统蜂群算法初始化和局部优化中存在的问... 详细信息

针对经典洗出算法参数选择不当导致信号缺失,引起失真,影响洗出效果等问题,提出一种改进的多目标人工蜂群算法,利用该算法对经典洗出算法中的滤波器参数进行优化来改善洗出算法的洗出效果。针对传统蜂群算法初始化和局部优化中存在的问题,引入Circle映射和Pareto局部优化算法;建立人体感知误差模型、加速度差值模型、位移模型,将模型函数作为目标函数,用改进后的多目标人工蜂群算法对经典洗出算法进行参数优化;建立仿真模型对优化后的洗出算法进行仿真验证,应用飞行模拟器运动实验平台进行实验验证。结果表明:经优化后的洗出算法,洗出逼真度得到有效提升,降低了误差峰值,改善了相位延迟,节省了运动空间。

关键词：多目标优化人工蜂群算法洗出算法参数优化动感逼真度

维普期刊数据库博看期刊

Generation of orbital angular momentum hologram using a modified u-net

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第3期33卷 401-407页

作者：郑志刚韩菲菲王乐赵生妹 Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology (Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing 210003China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China

Orbital angular momentum(OAM)holography has become a promising technique in information encryption,data storage and opto-electronic computing,owing to the infinite topological charge of one single OAM mode and the orthogonality of different OAM *** this paper,we propose a novel OAM hologram generation method based on a densely connected u-net(DCu),where the densely connected convolution blocks(DCB)replace the convolution blocks of the ***,the reconstruction process of the OAM hologram is integrated into DCu as its output layer,so as to eliminate the requirement to prepare training data for the OAM hologram,which is required by conventional neural networks through an iterative *** experimental and simulation results show that the OAM hologram can rapidly be generated with the well-trained DCu,and the reconstructed image's quality from the generated OAM hologram is significantly improved in comparison with those from the Gerchberg-Saxton generation method,the Gerchberg-Saxton based generation method and the u-net *** addition,a 10-bit OAM multiplexing hologram scheme is numerically demonstrated to have a high capacity with OAM hologram.

关键词： orbital angular momentum(OAM) holography OAM holography deep learning

新型农业经营主体生存动态演化的时空格局及其影响因素

在线全文

学校读者我要写书评

暂无评论

地理科学进展 2024年第1期43卷 47-62页

作者：麦强盛李乐西南林业大学会计学院昆明650233 西南林业大学经济管理学院昆明650233

研判新型农业经营主体发展的外部环境、内生动力和演化趋势,增强农业农村发展新动能,是关系中国农业农村现代化的重大战略。论文基于2000—2022年农业农村部公布的农业产业化国家重点龙头企业、全国农民合作社和家庭农场典型案例名单以... 详细信息

研判新型农业经营主体发展的外部环境、内生动力和演化趋势,增强农业农村发展新动能,是关系中国农业农村现代化的重大战略。论文基于2000—2022年农业农村部公布的农业产业化国家重点龙头企业、全国农民合作社和家庭农场典型案例名单以及中国农业企业黄页中的新型农业经营主体相关数据,通过空间计量分析和生存分析,探究其生存的空间格局及其影响因素。研究发现:①新型农业经营主体进入和退出农业市场的数量呈现倒“u”型曲线,实存数量呈逐渐上升的状态。②新型农业经营主体的生存时间在区域间形成差异化格局,高—高集聚区主要集中在中东部地区。③“个体特征和创新能力”因素对新型农业经营主体生存时间有正向影响,“阶段演变”对其生存时间有负向影响。④随着成立阶段的推移,新型农业经营主体资产规模和关联经济组织数量对其生存时间的影响作用逐渐下降,地理区域因素影响作用也逐渐减弱。研究结论可为新型农业经营主体生存分析提供实证依据,为分析其发展演化的地理特征提供借鉴参考。

关键词：新型农业经营主体生存时间时序格局阶段演变