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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

Prognostic implications of overt congestion in heart failure with preserved ejection fraction and the interaction with spironolactone:Insights from TOPCAT

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Chinese Medical Journal 2024年第10期137卷 1249-1251页

作者： Yingwen lin Hengli Zhao Dongtu Hu Jia Huang you Peng Juncong Li Dingli xu Qingchun Zeng State Key Laboratory of Organ Failure Research Department of CardiologyNanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China Guangdong Provincial Key Laboratory of Clinical Pharmacology Medical Research InstituteGuangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhouGuangdong 510515China Department of Radiology The Third Affiliated Hospital of Guangzhou Medical UniversityGuangzhouGuangdong 510150China Department of Obstetrics and Gynecology Nanfang HospitalSouthern Medical UniversityGuangzhouGuangdong 510515China

To the Editor:Heart failure with preserved ejection fraction(HFpEF)is a clinical entity characterized by impaired diastolic *** recently,there have been few studies directly evaluating how volume status impacts future cardiac events for patients with *** supporting the application of spironolactone in HFpEF is mainly derived from the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist(TOPCAT)*** though primary analysis of the trial reached a neutral result,subgroup and subsequent post hoc analyses have confirmed its efficacy in selected groups of patients,suggesting that identifying the potential subgroups of patients who would benefit from spironolactone treatment is important.[1]Data regarding the impact of congestion status on the efficacy of spironolactone in HFpEF are lacking.

关键词： function. fraction impaired

Automatic detection of breast lesions in automated 3D breast ultrasound with cross-organ transfer learning

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虚拟现实与智能硬件（中英文） 2024年第3期6卷 239-251页

作者： lingyun BAO Zhengrui HUANG Zehui lin Yue SUN Hui CHEN you LI Zhang LI Xiaochen YUAN lin xu Tao TAN Affiliated Hangzhou First People's Hospital School of MedicineWestlake UniversityHangzhou 330100China Faculty of Applied Sciences Macao Polytechnic UniversityMacao 999078China Pathology Department Changsha First HospitalChangsha 410073China Radiology Department Changsha First HospitalChangsha 410073China College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha 410073China School of Information Science and Technology Shanghaitech UniversityShanghai 201210China

Background Deep convolutional neural networks have garnered considerable attention in numerous machine learning applications,particularly in visual recognition tasks such as image and video *** is a growing interest in applying this technology to diverse applications in medical image *** three dimensional Breast Ultrasound is a vital tool for detecting breast cancer,and computer-assisted diagnosis software,developed based on deep learning,can effectively assist radiologists in ***,the network model is prone to overfitting during training,owing to challenges such as insufficient training *** study attempts to solve the problem caused by small datasets and improve model detection *** We propose a breast cancer detection framework based on deep learning(a transfer learning method based on cross-organ cancer detection)and a contrastive learning method based on breast imaging reporting and data systems(BI-RADS).Results When using cross organ transfer learning and BIRADS based contrastive learning,the average sensitivity of the model increased by a maximum of 16.05%.Conclusion Our experiments have demonstrated that the parameters and experiences of cross-organ cancer detection can be mutually referenced,and contrastive learning method based on BI-RADS can improve the detection performance of the model.

关键词： Breast ultrasound Automated 3D breast ultrasound Breast cancers Deep learning Transfer learning Convolutional neural networks Computer-aided diagnosis Cross organ learning

A novel rapid cooling assembly design in a high-pressure cubic press apparatus

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Matter and Radiation at Extremes 2024年第2期9卷 98-104页

作者： Peiyan Wu Yongjiang xu Yanhao lin Center for High Pressure Science and Technology Advanced Research Beijing 100193People’s Republic of China School of Earth Sciences and Resources China University of GeosciencesBeijing 100083People’s Republic of China

In traditional high-pressure–temperature assembly design, priority has been given to temperature insulation and retention at high *** limits the efficiency of cooling of samples at the end of experiments, with a negative impact on many studies in high-pressure Earth andplanetary science. Inefficient cooling of experiments containing molten phases at high temperature leads to the formation of quench textures,which makes it impossible to quantify key compositional parameters of the original molten phase, such as their volatile contents. Here,we present a new low-cost experimental assembly for rapid cooling in a six-anvil cubic press. This assembly not only retains high heatingefficiency and thermal insulation, but also enables a very high cooling rate (∼600 ℃/s from 1900 ℃ to the glass transition temperature).Without using expensive materials or external modification of the press, the cooling rate in an assembly (∼600 ℃/s) with cube lengths of38.5 mm is about ten times faster than that in the traditional assembly (∼60 ℃/s). Experiments yielding inhomogeneous quenched melttextures when the traditional assembly is used are shown to yield homogeneous silicate glass without quench textures when the rapid coolingassembly is used.

关键词： cubic insulation apparatus

Boundary Behaviors for a Continuous-state Nonlinear Neveu’s Branching Process

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Acta Mathematica Sinica,English Series 2024年第8期40卷 2005-2016页

作者： lin Yu BAI xu YANG School of Mathematics and Information Science North Minzu UniversityYinchuan 750021P.R.China

By generalizing a criterion of Mufa Chen for Markov jump processes,we establish the necessary and sufficient conditions for the extinction,explosion and coming down from infinity of a continuous-state nonlinear Neveu... 详细信息

关键词： Continuous-state branching process nonlinear branching Neveu’s branching extinction explosion coming down from infinity

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建筑用钢筋优化刍议

钢铁钒钛 2001年第1期22卷 7-15页

作者：徐有邻中国建筑科学研究院北京100013

我国钢筋种类繁多 ,强度偏低 ,部分钢筋延性太差 ,已难以适应混凝土结构发展的需要。基于混凝土结构对受力钢筋的要求 ,从强度、延性、质量稳定性、锚固性能、施工适应性及经济等方面对现有钢筋进行了分析比较。根据我国国情及建筑市场... 详细信息

我国钢筋种类繁多 ,强度偏低 ,部分钢筋延性太差 ,已难以适应混凝土结构发展的需要。基于混凝土结构对受力钢筋的要求 ,从强度、延性、质量稳定性、锚固性能、施工适应性及经济等方面对现有钢筋进行了分析比较。根据我国国情及建筑市场的变化 ,提出了大力推广Ⅲ级钢筋及中高强钢丝钢绞线 ,发展小直径Ⅱ、Ⅲ级钢筋 ,优化或淘汰冷加工钢筋 ,发展与钢筋有关的配套技术等建议。

关键词：混凝土结构钢筋优化建筑材料强度延性质量稳定性锚固性能施工适应性

Effect of hot isostatic pressure on the microstructure and tensile properties of γ'-strengthened superalloy fabricated through induction-assisted directed energy deposition

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1089-1097页

作者： Jianjun xu Hanlin Ding Xin lin Feng Liu Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core *** HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly *** further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained *** comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ ***,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.

关键词： directed energy deposition Ni-based superalloys high-temperature preheating hot isostatic pressing microstructure tensile properties

Thermal Decomposition and Oxidative Decomposition Mechanism of HFC-134a by Experimental and DFT Method

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Journal of Thermal Science 2024年第5期33卷 1990-2003页

作者： xu Yunting ZHANG Kai DAI Xiaoye SHI lin Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

In response to the Kigali Amendment to the Montreal Protocol and global low-carbon emission environmental requirements,the phase-out and decomposition of numerous HFC refrigerants have become urgent,necessitating efficient and mild decomposition *** study investigates the thermal decomposition and oxidative thermal decomposition pathways of the typical hydrofluorocarbon refrigerant HFC-134a,employing a combination of experimental and quantum chemical DFT simulation *** chemical simulations reveal that the initial reaction bond cleavage serves as the rate-determining step during the thermal decomposition process,with the most easily detectable closed-shell products including CF_(2)=CHF,HF,CH_(3)F,CHF_(3),CH_(2)F_(2),and CF_(4).Reactive oxygen species can significantly reduce the Gibbs free energy barrier for HFC-134a *** achieve efficient degradation of HFC-134a,appropriate catalysts should be developed and selected to increase the level of reactive oxygen species in the reaction *** studies further corroborate that HFC-134a may undergo degradation through distinct reaction pathways under varying temperature(240℃to360℃)and pressure(0.1 MPa to 4.5 MPa)conditions,in agreement with simulation predictions.

关键词： HFC-134a pyrolysis oxidative thermal decomposition DFT refrigerant

Transverse mode-coupling instability with longitudinal impedance

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Nuclear Science and Techniques 2024年第6期35卷 40-53页

作者： Hai-Sheng xu Chun-Tao lin Na Wang Jing-Ye xu Yuan Zhang Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Institute of Advanced Science Facilities Shenzhen 518107GuangdongChina

Transverse mode-coupling instability(TMCI)is a dangerous transverse single-bunch instability that can lead to severe par-ticle *** mechanism of TMCI can be explained by the coupling of transverse coherent oscillation modes owing to the transverse short-range wakefield(i.e.,the transverse broadband impedance).Recent studies on future circular colliders,e.g.,FCC-ee,showed that the threshold of TMCI decreased significantly when both longitudinal and transverse impedances were *** performed computations for the circular electron-positron collider(CEPC)and observed a similar *** studies on the influence of longitudinal impedance on the TMCI threshold were *** concluded that the imaginary part of the longitudinal impedance,which caused a reduction in the incoherent synchrotron tune,was the primary reason for the reduction in the TMCI ***,the real part of the longitudinal impedance assists in increasing the TMCI threshold.

关键词： Transverse mode-coupling instability Longitudinal impedance

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