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A novel stacking-based ensemble learning model for drilling efficiency prediction in earth-rock excavation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第12期23卷 1027-1046页

作者： fei lv Jia YU Jun ZHANG Peng YU Da-wei TONG Bin-ping WU State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300350China

Accurate prediction of drilling efficiency is critical for developing the earth-rock excavation schedule.The single machine learning(ML)prediction models usually suffer from problems including parameter sensitivity and overfitting.In addition,the influence of environmental and operational factors is often ignored.In response,a novel stacking-based ensemble learning method taking into account the combined effects of those factors is proposed.Through multiple comparison tests,four models,e Xtreme gradient boosting(XGBoost),random forest(RF),back propagation neural network(BPNN)as the base learners,and support vector regression(SVR)as the meta-learner,are selected for stacking.Furthermore,an improved cuckoo search optimization(ICSO)algorithm is developed for hyper-parameter optimization of the ensemble model.The application to a real-world project demonstrates that the proposed method outperforms the popular single ML method XGBoost and the ensemble model optimized by particle swarm optimization(PSO),with 16.43%and 4.88%improvements of mean absolute percentage error(MAPE),respectively.

关键词： Drilling efficiency Prediction Earth-rock excavation Stacking-based ensemble learning Improved cuckoo search optimization(ICSO)algorithm Comprehensive effects of various factors Hyper-parameter optimization

Recent advances in direct dehydrogenative biphenyl couplings

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Science China Chemistry 2017年第6期60卷 701-720页

作者： fei lv Zhu-Jun Yao State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringCollaborative Innovation Center of Chemistry for Life ScieneesNanjing UniversityNanjing 210023China

Biphenyl moiety represents a unique structural motif of many natural and unnatural products with biological interests, and dehydrogenative couplings of two aryl C–H bonds under oxidative conditions is unambiguously the most efficient and direct preparation of these compounds. However, higher oxidation potential of benzene derivatives makes such oxidative couplings much more difficult than other arenes. Only very limited advances have been achieved on direct formation of the crucial C–C bond between two phenyl derivatives by dehydrogenative phenyl coupling in the last two decades. This article briefly summarized and commented a number of representative recent achievements in this attractive field, including homo-, cross-and intramolecular rearrangement and couplings, as well as their applications in organic synthesis.

关键词：联苯结构脱氢联轴器氧化条件分子内重排耦合比衍生物制备方法

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浅析全国城市照明发展情况

城市照明 2024年第2期28卷 26-27,38页

作者：吕飞常州市城市照明管理处 213022

城市照明逐渐发展成为城市市政基础设施的重要组成部分。本文就近几年全国城市照明基本情况、推动城市照明发展的良好做法、城市照明目前存在的问题和提出的建议进行了多方面的阐述,以期对全国城市照明的发展提供参考价值。

关键词：城市照明行业监管绿色低碳

Efficient Access to Inverse Bicontinuous Mesophases via Polymerization-Induced Cooperative Assembly

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CCS Chemistry 2021年第8期3卷 2214-2225页

作者： fei lv Zesheng An Peiyi Wu State Key Laboratory of Supramolecular Structure and Materials College of ChemistryKey Laboratory for Molecular Enzymology and Engineering of Ministry of EducationSchool of Life SciencesJilin UniversityChangchun 130012 State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceLaboratory of Advanced MaterialsFudan UniversityShanghai 200433 State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of ChemistryChemical Engineering and BiotechnologyCenter for Advanced Low-Dimension MaterialsDonghua UniversityShanghai 201620

Polymerization-induced cooperative assembly(PICA)is reported to efficiently access inverse bicontinuous mesophases within particles consisting of amphiphilic block copolymers(BCPs)and solvophobic copolymers.Reversible addition-fragmentation chain transfer(RAFT)dispersion alternating copolymerization of styrene and pentafluorostyrene is conducted in 2%v/v toluene/ethanol by simultaneously using poly(N,N-dimethylacrylamide)(PDMA29)as a macromolecular chain transfer agent(macro-CTA)and small molecule CTA.

关键词： block copolymers bicontinuous mesophases cubosomes hexasomes polymerizationinduced self-assembly polymerization-induced cooperative assembly reversible additionfragmentation chain transfer

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高地应力隧道岩爆施工风险评估及管控措施

价值工程 2024年第6期43卷 33-35页

作者：吕飞李荣西安长安大学工程设计研究院有限公司西安710061

依托某隧道项目,通过收集项目的设计文件、地勘报告,分析项目的地应力背景、岩体的物理力学特性、对岩爆进行了预测与综合评价。并建立了高地应力隧道岩爆施工风险评估指标体系,提出了相应的控制措施。

关键词：高地应力岩爆风险评估管控措施

Influence of Island Scanning Strategy on Microstructures and Mechanical Properties of Direct Laser-Deposited Ti–6Al–4V Structures

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Acta Metallurgica Sinica(English Letters) 2019年第9期32卷 1173-1180页

作者： Xiao Wang fei lv Li-Da Shen Hui-Xin Liang De-Qiao Xie Zong-Jun Tian College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

To investigate the influence of island scanning on the microstructures and mechanical properties of direct laser-deposited Ti–6 Al–4 V structures,two samples are prepared using island scanning and orthogonal successive scanning,respectively.The microstructures,relative density,and mechanical properties of the samples prepared using these two scanning strategies are compared.Each sample exhibits columnarβ-grain morphology and basket-weave microstructure characterization.The grains of the sample prepared using island scanning are significantly finer than that prepared by orthogonal successive scanning due to faster cooling during deposition.However,the relative density of the sample prepared using island scanning was slightly smaller due to the concentration of lack-of-fusion pores at the overlap zone of the island.Tensile testing at room temperature indicates that the ultimate tensile strength and yield strength of the sample prepared using island scanning is enhanced due to finer grains,while the ductility of the sample is weakened due to defects.

关键词： Direct laser deposition Ti-6A1W Scanning strategies Microstructure Defects Mechanical property

A Review on Distortion and Residual Stress in Additive Manufacturing

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Chinese Journal of Mechanical Engineering(Additive Manufacturing Frontiers) 2022年第3期1卷 58-68页

作者： Deqiao Xie fei lv Youwen Yang Lida Shen Zongjun Tian Cijun Shuai Bo Chen Jianfeng Zhao College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing210016China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing210016China Institute of Bioadditive Manufacturing Jiangxi University of Science and TechnologyNanchang330044China School of Engineering University of LeicesterLeicesterLE17RHUK

Additive manufacturing(AM)has gained extensive attention and tremendous research due to its advantages of fabricating complex-shaped parts without the need of casting mold.However,distortion is a known issue for many AM technologies,which decreases the precision of as-built parts.Like fusion welding,the local high-energy input generates residual stresses,which can adversely affect the fatigue performance of AM parts.To the best of the authors’knowledge,a comprehensive review does not exist regarding the distortion and residual stresses dedicated for AM,despite some work has explored the interrelationship between the two.The present review is aimed to fill in the identified knowledge gap,by first describing the evolution of distortion and residual stresses for a range of AM processes,and second assessing their influencing factors.This allows us to elucidate their formation mechanisms from both the micro-and macro-scales.Moreover,approaches which have been successfully adopted to mitigate both the distortion and residual stresses are reviewed.It is anticipated that this review paper opens many opportunities to increase the success rate of AM parts by improving the dimension precision and fatigue life.

关键词： Additive manufacturing Distortion Residual stress Selective laser melting Laser melting deposition

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基于PFC控制的船舶充电装置设计

船电技术 2024年第4期44卷 90-93页

作者：王冕吕飞赵丰刚海军蚌埠士官学校安徽蚌埠233012

根据某船舶充电需求,本文提出一种基于PFC控制的高功率因数、隔离性的充电装置设计方案。详细介绍了Pfc-boost拓扑结构电路、隔离斩波拓扑电路及DSP芯片的外围硬件电路。通过实验仿真验证,该方案能够满足设计目标,实现稳定输出。

关键词：船舶充电 PFC-Boost 高功率因数

A case of a successful post-transcatheter aortic valve replacement His bundle pacing

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World Journal of Emergency Medicine 2021年第2期12卷 157-159页

作者： fei lv Xiao-hong Pan Jia-qi Fan Li-han Wang Dan-dan Yang Xin-ping Lin Hua-jun Li Qi-feng Zhu Xian-baoLiu Jian-an Wang Department of Cardiology the Second Affi liated HospitalZhejiang University School of MedicineHangzhou 310009China

Dear editor,Transcatheter aortic valve replacement (TAVR) is a safe and effective treatment for severe aortic valve stenosis and aortic regurgitation. Multiple randomized trials have proved its therapeutic advantages ... 详细信息

关键词： aortic stenosis bundle