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Prediction of contact resistance of electrical contact wear using different machine learning algorithms

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Friction 2024年第6期12卷 1250-1271页

作者： zhen-bing cai Chun-lin LI Lei YOU Xu-dong CHEN Li-ping HE Zhong-qing CAO Zhi-nan ZHANG Tribology Research Institute Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China

H62 brass material is one of the important materials in the process of electrical energy transmission and signal transmission,and has excellent performance in all *** the wear behavior of electrical contact pairs is particularly complex when they are in service,we evaluated the effects of load,sliding velocity,displacement amplitude,current intensity,and surface roughness on the changes in contact *** learning(ML)algorithms were used to predict the electrical contact performance of different factors after wear to determine the correlation between different factors and contact *** forest(RF),support vector regression(SVR)and BP neural network(BPNN)algorithms were used to establish RF,SVR and BPNN models,respectively,and the experimental data were trained and *** was proved that BP neural network model could better predict the stable mean resistance of H62 brass alloy after *** analysis shows that the load and current have great influence on the predicted electrical contact *** wear behavior of electrical contacts is influenced by factors such as load,sliding speed,displacement amplitude,current intensity,and surface roughness during *** learning algorithms can predict the electrical contact performance after wear caused by these *** results indicate that an increase in load,current,and surface roughness leads to a decrease in stable mean resistance,while an increase in displacement amplitude and frequency results in an increase in stable mean resistance,leading to a decline in electrical contact *** reduce testing time and costs and quickly obtain the electrical contact performance of H62 brass alloy after wear caused by different factors,three algorithms(random forest(RF),support vector regression(SVR),and BP neural network(BPNN))were used to train and test experimental results,resulting in a machine learning model suitable for predicting the stable mean

关键词： electrical contact wear contact resistance machine learning(ML) neural network

Dielectric Constant Calculation of Poly(vinylidene fluoride)Based on Finite Field and Density Functional Theory

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Chinese Journal of Polymer Science 2024年第5期42卷 655-662,I0009页

作者： Yong-Zhi Lin Lu-Kun Feng Ya-Dong Li Chao-Fan Chang cai-zhen Zhu Ming-Liang Wang Jian Xu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen518055China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu610041China

In this study,we proposed a novel method that integrates density functional theory(DFT)with the finite field method to accurately estimate the polarizability and dielectric constant of *** approach effectively accounts for the influence of electronic and geometric conformation changed on the dielectric *** validated our method using polyethylene(PE)and polytetrafluoroethylene(PTFE)as benchmark materials,and found that it reliably predicted their dielectric ***,we explored the impact of conformation variations in poly(vinylidene fluoride)(PVDF)on its dielectric constant and *** resulting dielectric constants ofα-andγ-PVDF(3.0)showed excellent agreement with crystalline PVDF in *** findings illuminate the relationship between PVDF’s structural properties and its electrical behavior,offering valuable insights for material design and applications.

关键词： Dielectric constant PVDF Finite field DFT

High-Performance Recyclable Furan-based Epoxy Resin and Its Carbon Fiber Composites with Dense Hydrogen Bonding

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Chinese Journal of Polymer Science 2024年第1期42卷 73-86,I0008页

作者： Chang-Bo Zhao Lu-Kun Feng Hui Xie Ming-Liang Wang Bing Guo Zhi-Yong Xue cai-zhen Zhu Jian Xu Advanced Materials Research Institute North China Electric Power UniversityBejing 102206China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China School of Science and Shenzhen Key Laboratory of Flexible Printed Electronics Technology and Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive ApplicationHarbin Institute of TechnologyShenzhen 518055China

The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of *** the existence of dynamic chemical bonds in vitrimers often reduces both the thermal and mechanical properties of epoxy resins, it is challenging to produce recyclable epoxy vitrimers with both excellent mechanical properties and good thermal stability. Herein, a monomer 4-(((5-(hydroxymethyl)furan-2-yl)methylene)amino)phenol(FCN) containing furan ring with potential to form high density of hydrogen bonding among repeating units is designed and copolymerized with glycerol triglycidyl ether to yield epoxy resin(FCN-GTE), which intrinsically has dual hydrogen bond networks, dynamic imine structure and resultant high performance. Importantly, as compared to the BPA-GTE, the FCN-GTE exhibits significantly improved mechanical properties owing to the increased density of hydrogen bond network and physical crosslinking interaction. Furthermore, density functional theory(DFT) calculation and in situ FTIR analysis is conducted to decipher the formation mechanism of hydrogen bond network. In addition, the FCN-GTE possesses superior UV shielding, chemical degradation, and recyclability because of the existence of abundant imine bonds. Notably, the FCN-GTE-based carbon fiber composites could be completely recycled in an amine *** study provides a facile strategy for synthesizing recyclable biomass-based high-performance epoxy vitrimers and carbon fiber composites.

关键词： Furan Hydrogen bond network Dynamic Schiff base Carbon fiber composites Recycling

Molecular Chain Flexibility and Dielectric Loss at High-Frequency:Impact of Ester Bond Arrangement in Poly(ester imide)s

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Chinese Journal of Polymer Science 2024年第8期42卷 1122-1133页

作者： Ya-Dong Li Hong Li Lu-Kun Feng Feng Bao Ming-Liang Wang cai-zhen Zhu Zhao-Hui zheng Xiao-Bin Ding Jian Xu Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100081China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China

The evolution of high-frequency communication has accentuated the significance of controlling dielectric properties in polymer ***,it has been theorized that rigid molecular chains lead to lower dielectric ***,the validity of this proposition at high frequencies remains *** scrutinize the correlation between chain flexibility and dielectric properties,we synthesized six poly(ester imide)s(PEIs)with systematically varied molecular chain flexibilities by modifying the ester's substitution on the aromatic *** introduction of ester bonds bestowed all PEI films with a low dielectric dissipation factor(D_(f)),ranging from 0.0021 to 0.0038 at 10 GHz in dry *** dry D_(f)displayed a pattern consistent with volume polarizability(P/V).Unexpectedly,PI-mmm-T,featu ring the most flexible molecular chain,exhibited the lowest dielectric loss under both dry(0.0021@10 GHz)and hygroscopic(0.0029@10 GHz)***,the observed increase in D_(f)after humidity absorption suggests that the high dielectric loss of PEI in applications may be attributed to its hygroscopic *** simulations and characterization of the aggregation structure revealed that the smaller cavities within flexible molecular chains,after close stacking,impede the entry of water *** sacrificing high-temperature resistance,the precursor exhibited enhanced solubility properties and could be processed into high-quality *** research unveils new insights into the relationship between flexibility and highfrequency dielectric loss,offering innovative perspectives on synthesizing aromatic polymers with exceptional dielectric properties.

关键词： 5G communications Poly(ester imide)s Molecular chain flexibility Dielectric properties Humidity absorption

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神经科学启示下的共情与道德

自然辩证法通讯 2024年第5期46卷 41-48页

作者：蔡蓁华东师范大学哲学系上海200241

在共情的跨学科研究日益深入的背景下,对共情的道德作用的讨论受到了来自于神经科学的诸多启发。首先,神经科学的研究揭示出情绪要素和认知要素是如何通过既彼此独立又相互交叉的神经网络,在我们的大脑中产生出对他人的共情反应。进而,... 详细信息

在共情的跨学科研究日益深入的背景下,对共情的道德作用的讨论受到了来自于神经科学的诸多启发。首先,神经科学的研究揭示出情绪要素和认知要素是如何通过既彼此独立又相互交叉的神经网络,在我们的大脑中产生出对他人的共情反应。进而,神经科学对同时具有道德缺陷和共情缺陷的心理变态者的研究表明,一种动态的、情绪与认知相互作用的共情能力对正常的道德能力来说是必不可少的,这也构成了对以共情为基础的情感主义立场的有益补充。

关键词：共情道德能力神经科学心理变态

公众参与与政府响应视角下的环境治理机制及效果

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经济学动态 2024年第5期 72-88页

作者：蔡真万兆中国社会科学院金融研究所中国社会科学院大学 100710 东南大学经济管理学院东南大学国家发展与政策研究院 211189

国家环境治理体系的完善对实现“人与自然和谐共生的现代化”具有重要意义。本文基于中国A股上市企业、各省、地级市、省直辖县数据,从中国公众参与与政府响应相结合的视角切入,实证分析了中国公众参与环境治理的有效途径与环境治理效... 详细信息

国家环境治理体系的完善对实现“人与自然和谐共生的现代化”具有重要意义。本文基于中国A股上市企业、各省、地级市、省直辖县数据,从中国公众参与与政府响应相结合的视角切入,实证分析了中国公众参与环境治理的有效途径与环境治理效应。研究发现:公众环境问题关切可以促进企业增加环保投资;公众有效的环保行动与政府积极的环境治理响应,是公众促进企业增加环保投资的主要作用机制;公众环境问题关切可以同时显著促进企业增加末端治理与源头控制类环保投资;公众不同类型的环境问题关切对企业环保投资的促进作用存在差异;企业特征方面,国有、低融资约束、高盈利能力企业受公众环境问题关切的促进作用更加显著;地区特征方面,工业企业经济贡献小、政府经济业绩压力小的地区,公众环境问题关切的促进作用更加显著。本文的研究为中国环境治理机制及效果提供了直接、系统的研究证据,总结了既往制度在公众参与环境治理过程中的不足,为完善多元共治环境治理体系、促进企业实施环保投资提供了一定经验证据与政策启示。

关键词：多元共治环境治理体系公众环境问题关切政府积极响应

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郭沫若诗话(九)

郭沫若学刊 2024年第2期 63-68页

作者：蔡震中国社会科学院北京郭沫若纪念馆北京100007

百花拾遗1958年3月30日起,郭沫若用十天时间,连续创作了一百余首咏花的诗,辑成诗歌集《百花齐放》。这是独立成集的一部诗歌作品。事实上还在1956年,郭沫若就有了以百花为题材创作一组诗歌的想法。这应该与“百花齐放”文艺方针的提出... 详细信息

百花拾遗1958年3月30日起,郭沫若用十天时间,连续创作了一百余首咏花的诗,辑成诗歌集《百花齐放》。这是独立成集的一部诗歌作品。事实上还在1956年,郭沫若就有了以百花为题材创作一组诗歌的想法。这应该与“百花齐放”文艺方针的提出有关。1956年4月,中共中央将“百花齐放,百家争鸣”确定为繁荣和发展社会主义科学文化事业的指导方针。

关键词：郭沫若诗诗歌作品诗歌集科学文化事业文艺方针百花齐放指导方针百家争鸣

孪生数据驱动的大型矿井提升机主轴承随机振动系统的设计可靠性分析

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振动工程学报 2024年第6期37卷 915-927页

作者：曹爽卢昊朱真才张义民中国矿业大学机电工程学院江苏徐州221008 中国矿业大学江苏省矿山机电装备高校重点实验室江苏徐州221008 沈阳化工大学机械与动力工程学院辽宁沈阳110142

设计阶段的大型矿井提升机主轴承随机振动系统的设计可靠性分析因试验样本不足,无法获取振动加速度响应的完备概率信息。提出了概率信息不完备下大型矿井提升机主轴承设计可靠性分析的技术路线:滚动轴承多尺度耦合系统动力学模型-振动... 详细信息

设计阶段的大型矿井提升机主轴承随机振动系统的设计可靠性分析因试验样本不足,无法获取振动加速度响应的完备概率信息。提出了概率信息不完备下大型矿井提升机主轴承设计可靠性分析的技术路线:滚动轴承多尺度耦合系统动力学模型-振动加速度概率密度演化-概率密度演化路径随机过程建模-振动功率谱密度的概率分布-基于条件概率的设计可靠度计算。运用已采集的工况数据驱动建立滚动轴承多尺度耦合系统动力学模型,开展了振动加速度概率密度演化研究;基于概率密度演化和Karhunen-Loève展开,提出了滚动轴承振动加速度的非平稳随机过程建模方法,获得了滚动轴承振动加速度随机序列的孪生数据;研究了大型矿井提升机主轴承振动加速度功率谱密度的概率分布,并计算了大型矿井提升机主轴承在服役时间上的设计可靠度指标。

关键词：随机振动设计可靠性分析孪生数据大型矿井提升机主轴承概率信息不完备

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ChatGPT的法律人格认定与生成内容性质探讨

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新疆师范大学学报（哲学社会科学版） 2024年第3期45卷 96-103页

作者：蔡镇疆车宇璐新疆大学法学院新疆乌鲁木齐830046

随着ChatGPT的广泛运用,关于人工智能的法律问题探讨再次成为舆论焦点。根据ChatGPT系统与人类互动生成相应文字内容的特性,ChatGPT生成内容是否受《著作权法》保护问题备受争议。探讨该问题,有两个不可或缺的前提要件,即ChatGPT是否具... 详细信息

随着ChatGPT的广泛运用,关于人工智能的法律问题探讨再次成为舆论焦点。根据ChatGPT系统与人类互动生成相应文字内容的特性,ChatGPT生成内容是否受《著作权法》保护问题备受争议。探讨该问题,有两个不可或缺的前提要件,即ChatGPT是否具有法律人格及其生成内容能否被认定为作品,以此确定其是否应受《著作权法》保护。文本认为,ChatGPT尚不具备法律主体资格,在ChatGPT生成内容被认定为作品对其进行保护时,应明确ChatGPT使用者作为生成内容的著作权主体,通过加强对ChatGPT著作权主体的监管实现对其生成内容的规制,以此加快推进人工智能法治化进程。

关键词： ChatGPT 法律人格作品著作权