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激光与光电子学进展 2024年第11期 60-66页

作者： Su Yawen Chen Haiwei Zhao Mengwei Niu Yunfei li Chen Zhang Yong Yang Shaoguang Zhu Shining Hu xiaopeng National Laboratory of Solid State Microstructures School of Physics College of Engineering and Applied Sciences Nanjing University Zhejiang Laboratory

Conductive ferroelectric domain walls have attracted increasing research interest in the field of nanoelectronics, and the fabrication technique for such domain walls is vital. In this study, we investigated in detail the fabrication of conductive domain walls in x-cut congruent thin-film lithium niobate(TFLN) using an electrical-field poling technique. The ferroelectric domain structures can be controlled through the applied electrical field and applied pulse numbers, and the domain inversion process is related to the conduction characteristics of the domain walls. The domain structures in TFLN are revealed using confocal second-harmonic microscopy and piezoresponse force microscopy. The results provide further directions for the development and application of conductive domain walls in TFLN.

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A machine learning method to quantitatively predict alpha phase morphology in additively manufactured Ti-6Al-4V

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npj Computational Materials 2023年第1期9卷 338-352页

作者： Zhuohan Cao Qian liu Qianchu liu Xiaobo Yu Jamie J.Kruzic xiaopeng li School of Mechanical and Manufacturing Engineering University of New South Wales(UNSW Sydney)SydneyNSW 2052Australia Platforms Division Defence Science and Technology GroupMelbourneVIC 3207Australia

Quantitatively defining the relationship between laser powder bed fusion(LPBF)process parameters and the resultant microstructures for LPBF fabricated alloys is one of main research challenges.To date,achieving the desired microstructures and mechanical properties for LPBF alloys is generally done by time-consuming and costly trial-and-error experiments that are guided by human experience.Here,we develop an approach whereby an image-driven conditional generative adversarial network(cGAN)machine learning model is used to reconstruct and quantitatively predict the key microstructural features(e.g.,the morphology of martensite and the size of primary and secondary martensite)for LPBF fabricated Ti-6Al-4V.The results demonstrate that the developed image-driven machine learning model can effectively and efficiently reconstruct micrographs of the microstructures within the training dataset and predict the microstructural features beyond the training dataset fabricated by different LPBF parameters(i.e.,laser power and laser scan speed).This study opens an opportunity to establish and quantify the relationship between processing parameters and microstructure in LPBF Ti-6Al-4V using a GAN machine learning-based model,which can be readily extended to other metal alloy systems,thus offering great potential in applications related to process optimisation,material design,and microstructure control in the additive manufacturing field.

关键词： martensite microstructure alloy

Longitudinal control for person-following robots

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Journal of Intelligent and Connected Vehicles

Journal of Intelligent and Connected Vehicles 2022年第2期5卷 88-98页

作者： liang Wang Jiaming Wu xiaopeng li Zhaohui Wu lin Zhu China Academy of Transportation Sciences BeijingChina Department of Architecture and Civil Engineering Chalmers University of TechnologyGothenburgSweden University of South Florida TampaFloridaUSA

Purpose–This paper aims to address the longitudinal control problem for person-following robots(PFRs)for the implementation of this technology.Design/methodology/approach–Nine representative car-following models are analyzed from PFRs application and the linear model and optimal velocity model/full velocity difference model are qualified and selected in the PFR control.Findings–A lab PFR with the bar-laser-perception device is developed and tested in the field,and the results indicate that the proposed models perform well in normal person-following scenarios.Originality/value–This study fills a gap in the research on PRFs longitudinal control and provides a useful and practical reference on PFRs longitudinal control for the related research.

关键词： Person following robot Longitudinal control model Parameter optimization

混合级联特高压直流输电线路纵联差动保护适应性分析

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电网技术 2024年第5期48卷 2170-2178,I0105-I0107页

作者：牟大林林圣李小鹏西南交通大学电气工程学院四川省成都市611756 国网四川省电力公司电力科学研究院四川省成都市610041

为探究现有高压直流输电线路纵联差动保护对混合级联特高压直流输电系统的适应性,结合混合级联特高压直流输电系统的运行方式,理论分析和仿真分析3种特殊运行方式下直流系统不同位置故障的故障特性和保护适应性。理论分析发现纵联差动... 详细信息

为探究现有高压直流输电线路纵联差动保护对混合级联特高压直流输电系统的适应性,结合混合级联特高压直流输电系统的运行方式,理论分析和仿真分析3种特殊运行方式下直流系统不同位置故障的故障特性和保护适应性。理论分析发现纵联差动保护适应性较好。仿真分析发现直流线路分布电容和逆变侧模块化多电平型换流器(modular multilevelconverter,MMC)控制特性影响在直流线路故障时直流线路电流延时自减值长时间处于波动状态,导致纵联差动保护长时间处于闭锁状态,此时,系统长时间承受MMC超大故障电流冲击。直流线路区外故障时整流侧与逆变侧直流电流差值的绝对值数值较大且长时间处于波动变化状态,纵联差动保护存在误动的风险。

关键词：混合级联特高压直流输电系统纵联差动保护适应性分析运行方式保护误动

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Weighted EP of Block Operator Matrices

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Journal of Mathematical Research with Applications 2022年第3期42卷 230-242页

作者： xiaopeng li Junjie HUANG Alatancang CHEN School of Mathematical Sciences Inner Mongolia University Inner Mongolia Normal University

In this paper, we introduce and study the weighted Moore-Penrose invertible and weighted-EP of block operator matrices in the context of Hilbert spaces, based on the weighted generalized Schur complement. Furthermore,... 详细信息

关键词： EP operator weighted-EP operator operator matrix weighted generalized inverse

Two-dimensional atomically thin Pt layers on MXenes: The role of electronic effects during catalytic dehydrogenation of ethane and propane

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Nano Research 2024年第3期17卷 1251-1258页

作者： Zhe li Tobias K.Misicko Fan Yang xiaopeng liu Zhenwei Wu Xiaoyang Gao Tao Ma Jeffrey T.Miller Daniela S.Mainardi Collin D.Wick Zhenhua Zeng Yang Xiao Yue Wu Department of Chemical and Biological Engineering Iowa State University618 Bissell RoadAmesIA 50011USA Institute for Micromanufacturing Louisiana Tech University505 Tech DriveRustonLA 71272USA Davidson School of Chemical Engineering Purdue University480 Stadium Mall DriveWest LafayetteIN 47907USA Michigan Center for Materials Characterization University of Michigan2800 Plymouth RdAnn Arbor MI 48109USA College of Engineering and Science Louisiana Tech UniversityRustonLA 71272USA

Atomically thin Pt nanolayers were synthesized on the surface of Mo2TiC2 MXenes and used for the catalytic dehydrogenation of ethane and propane into ethylene and propylene,two important chemicals for the petrochemical industry.As compared with Pt nanoparticles,the atomically thin Pt nanolayer catalyst showed superior coke-resistance(no deactivation for 24 h),high activity(turnover frequencies(TOFs)of 0.4–1.2 s^(-1)),and selectivity(>95%)toward ethylene and propylene.The unique Pt nanolayer has a similar geometric surface to Pt nanoparticles,enabling the investigations of the electronic effect on the catalytic performance,where the geometric effect is negligible.It is found that the electronic effect plays a critical role in dehydrogenative product selectivity and catalyst stability.The metal–support interaction is found dependent on the substrate and metal components,providing wide opportunities to explore high-performance MXene-supported metallic catalysts.

关键词： MXene catalysis alkane dehydrogenation nanolayers

Boosting Hydrogen Evolution and Oxygen Reduction Performances of Pd/C upon Surface Phosphorization

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Journal of Harbin Institute of Technology(New Series) 2022年第6期29卷 74-88页

作者： Tongtong Zhu Haige Wang xiaopeng li Yaozu liao Meifang Zhu State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China

Simultaneous heterostructure and composition engineering is an effective route to construct electrocatalyst of high performance. Conjugated microporous polymer(CMP) is a new emerging platform material with designable porosity and functionality. Here, a facile CMP-guest chemistry method was presented to prepare PdP2@Pd/C heterostructure with bifunctional electrocatalytic activity. The formation of heterostructure relies on a CMP precursor consisting of nitrogen groups that allow binding Pd species and introducing phosphorus inclusion. The Pd-bound CMP precursor formed in-situ could be directly converted into nitrogen-and phosphide-doped porous carbon(NPC) during pyrolysis, while P diffused to the Pd/C interface results in shallow phosphorization. The as-prepared NPC consisting of PdP2@Pd/C(Pd content 4 wt%) heterostructure demonstrated significantly enhanced electrocatalytic performances including a promising HER activity(58mV @ 10 mA/cm2), and an ORR activity approaching commercial 20 wt% Pd/C together with excellent long-term stability. Our work illustrates the intriguing power of CMP-guest potential in heterostructure engineering.

关键词： Conjugated microporous polymers Palladium phosphide heterostructures Bifunctional electrocatalysts Hydrogen evolution reaction Oxygen reduction reaction Document Code

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Effect of grain refinement on cutting force of difficult-to-cut metals in ultra-precision machining

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Chinese Journal of Aeronautics 2022年第3期35卷 484-493页

作者： Renjie JI Qian ZHENG Yonghong liU Hui JIN Fan ZHANG Shenggui liU Baokun WANG Shuaichen LU Baoping CAI xiaopeng li College of Mechanical and Electronic Engineering China University of Petroleum(East China)Qingdao 266580China

The nickel-based superalloy Inconel 718 is treated with Coupled Ultrasonic and Electric Pulse Treatment(CUEPT),and the surface grain is refined from the average size of 9550.0 nm to287.9,216.3,150.5,126.3,25.8 nm by different effective treatment currents,respectively.The ultraprecision turning experiments are carried out on the processed workpiece after CUEPT.The experimental results show that the average cutting force increases with the decrease of surface grain size.Moreover,a mathematical model that can describe the relationship between grain size and cutting force is established,and the calculated results match the experimental results well.The calculated results also indicate that the variation of cutting force caused by the same variation of grain size decreases as the degree of grain refinement increases.Finally,the influence mechanism of grain refinement on cutting force is analyzed.The improvement of stability of grain boundaries and the increase of number of grain boundaries cause the increase of cutting force after grain refinement.

关键词： Grain size Cutting force Difficult-to-cut metals Grain refinement Ultra-precision machining Cou-pled ultrasonic and electric pulse treatment

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A telomere-to-telomere gap-free reference genome of watermelon and its mutation library provide important resources for gene discovery and breeding

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Molecular Plant 2022年第8期15卷 1268-1284页

作者： Yun Deng Shoucheng liu Yilin Zhang Jingsheng Tan xiaopeng li Xiao Chu Binghua Xu Yao Tian Yudong Sun Bosheng li YunbiXu Xing Wang Deng Hang He Xingping Zhang Peking University Institute of Advanced Agricultural Sciences Shandong Laboratory of Advanced Agricultural Sciences at WeifangWeifangShandong 261000China School of Advanced Agricultural Sciences and School of life Sciences State Key Laboratory of Protein and Plant Gene ResearchPeking UniversityBeijing 100871China Jiangsu Xuhuai Area Huaiyin Institute of Agricultural Science HuaianJiangsu 223300China

Watermelon,Citrullus lanatus,is the world's third largest fruit crop.Reference genomes with gaps and a narrow genetic base hinder functional genomics and genetic improvement of watermelon.Here,we report the assembly of a telomere-to-telomere gap-free genome of the elite watermelon inbred line G42 by incorporating high-coverage and accurate long-read sequencing data with multiple assembly strategies.All 11 chromosomes have been assembled into single-contig pseudomolecules without gaps,representing the highest completeness and assembly quality to date.The G42 reference genome is 369321829 bp in length and contains 24205 predicted protein-coding genes,with all 22 telomeres and 11 centromeres characterized.Furthermore,we established a pollen-EMS mutagenesis protocol and obtained over 200000M1 seeds from G42.In a sampling pool,48 monogenic phenotypic mutations,selected from 223M1and 78 M2 mutants with morphological changes,were confirmed.The average mutation density was 1 SNP/1.69Mband1 indel/4.55 Mb per M1 plant and 1SNP/1.08Mb and 1 indel/6.25 Mb per M2 plant.Taking advantage of the gap-free G42 genome,8039 mutations from 32 plants sampled from M1 and M2 families were identified with 100%accuracy,whereas only 25% of the randomly selected mutations identified using the 97103v2 reference genome could be confirmed.Using this library and the gap-free genome,two genes responsible for elongated fruit shape and male sterility(CiMs1)were identified,both caused by a single basechange from G to A.The validated gap-free genome and its EMS mutation library provide invaluable resources for functional genomics and genetic improvement of watermelon.

关键词： watermelon gap-free genome EMS,mutation library gene discovery genome-wide sequencing genic male sterility

Exploring Antarctic subglacial lakes with RECoverable Autonomous Sonde(RECAS): Design and first field tests

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Science China Technological Sciences 2024年第6期67卷 1866-1878页

作者： SUN YouHong PAVEL Talalay li YuanSheng YU HaiBin WANG Dongliang li GuoPing XU liPing GONG Da WANG JiXin WANG JianHua WANG Ting ZHANG Nan WANG ZhiGang CHEN YanJi liU YunChen li YaZhou PENG Shilin SHI JianGuang AN ChunLei GE Qun XU Jing NI XiaoKang CUI QiFeng JIANG Qiang MIKHAIL Sysoev Yang Yang WANG RuSheng WEI XianZhe WANG Yu ZHU TianXin DENG ZhiPeng ALEXEY Markov li Bing FAN xiaopeng Polar Research Center Jilin University School of Engineering and Technology China University of Geosciences Polar Research Institute of China College of Electronics and Information Hangzhou Dianzi University Aerospace System Engineering Shanghai Nanjing Institute of Astronomical Optics & Technology National Astronomical ObservatoriesChinese Academy of Sciences National Ocean Technology Center

Conducting scientific drilling on subglacial lakes and obtaining samples of subglacial lake water holds great significance in unraveling the formation and evolution of Antarctic subglacial lakes and early Earth's life forms. Despite various approaches to access and directly sample subglacial water and sediments, clean access and exploration of subglacial lakes remain challenging.To address this concern, Jilin University has developed the RECoverable Autonomous Sonde(RECAS) prototype. This technology enables sampling and in-situ detection of subglacial lake water while being isolated from the surface, thus minimizing the risk of pollution. Laboratory tests, including downward and upward drilling, long-running, remote-control, and cold-environment assessments, were conducted to validate the sonde's principle and functionality. During the 38th Chinese National Antarctic Research Expedition, CHINARE(2021–2022 season), the RECAS prototype underwent testing on the flank region of D?lk glacier, 10 km from Zhongshan Station in Antarctica. Three boreholes with depths of 200.3, 183.2, and 133.5 m were successfully drilled, with the refrozen meltwater sealing the boreholes during the process. Approximately 600 mL of melted water samples were collected from each hole. Throughout the drilling tests, all systems of the RECAS prototype performed within the expected ranges.

关键词： subglacial lake thermal drilling water sampling Antarctic autonomous sonde