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激光旁轴送丝熔覆堆积成形焊缝特征拟合及最佳搭接率模型验证

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应用激光 2024年第6期44卷 53-59页

作者：李松钊朱加雷赵晓鑫黄钰连朱昱颖宋旷达李桂新黄钰珊北京石油化工学院机械工程学院北京102617 上海民办圣华紫竹双语学校上海200241

在激光旁轴送丝熔覆成形中,表面平整度是影响其成形质量的关键因素。为获得理想的表面平整度,选取ER-2209焊丝,基于激光旁轴送丝单层单道熔覆焊缝形貌,使用MATLAB软件对其进行图像处理、焊缝特征提取及数学拟合。试验结果表明,传统焊缝... 详细信息

在激光旁轴送丝熔覆成形中,表面平整度是影响其成形质量的关键因素。为获得理想的表面平整度,选取ER-2209焊丝,基于激光旁轴送丝单层单道熔覆焊缝形貌,使用MATLAB软件对其进行图像处理、焊缝特征提取及数学拟合。试验结果表明,传统焊缝的抛物线模型与实际熔覆焊缝特征差异较大,为保证误差可控,同时避免不利因素的产生,经过多组不同阶数的拟合结果对比发现,使用6阶函数对试验对象的拟合效果更好。由焊缝曲线的拟合结果可得出最优拟合函数,进而利用微分的思想建立最佳平整度的数学模型,可求解出最佳理论搭接率,并通过5组单因素激光旁轴送丝搭接试验对所提出的表面平整度模型进行验证。结果表明,焊缝表面平整度是焊缝特征和层间偏移量的函数;该模型的理论最佳搭接率是30.45%,试验验证的理想搭接率在30%~35%之间,在试验误差允许范围内理论最佳搭接率成立。在实际的激光旁轴送丝熔覆成形过程中,可以根据实际情况,在理论最优搭接率基础上小范围灵活调整。

关键词：激光旁轴送丝熔覆成形技术图像处理焊缝轮廓拟合搭接率模型单因素试验

Thermal energy dependent transient permittivity of epsilon-near-zero material

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Science China(Physics,Mechanics & Astronomy) 2022年第8期65卷 96-101页

作者： Heng Wang lixun Sun Kang Du Wending Zhang SooJin Chua guixin li Ting Mei MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information TechnologySchool of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an710129China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen518055China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen518055China Department of Electrical and Computer Engineering National University of SingaporeSingapore117583Singapore LEES Program Singapore-MIT Alliance for Research&Technology(SMART)Singapore138602Singapore

Transparent conductive oxides exhibit attractive optical nonlinearity with ultrafast response and giant refractive index change near the epsilon-near-zero(ENZ) wavelength, originating from the intraband dynamics of conduction electrons. The optical nonlinearity of ENZ materials has been explained by using the overall-effective-mass and the overall-scattering-time of electrons in the extended Drude model. However, their response to optical excitation is yet the last building block to complete the theory. In this paper, the concept of thermal energy is theoretically proposed to account for the total energy of conduction electrons exceeding their thermal equilibrium value. The time-varying thermal energy is adopted to describe the transient optical response of indium-tin-oxide(ITO), a typical ENZ material. A spectrally-resolved femtosecond pump-probe experiment was conducted to verify our theory. By correlating the thermal energy with the pumping density, both the giant change and the transient response of the permittivity of ITO can be predicted. The results in this work provide a new methodology to describe the transient permittivities of ENZ materials, which will benefit the design of ENZ-based nonlinear photonic devices.

关键词： epsilon-near-zero optical nonlinearity transient response thermal energy hot electron indium tin oxide

A Global Seamless Hybrid Constellation Design Approach with Restricted Ground Supporting for Space Information Network

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Journal of Systems Science and Information 2019年第3期10卷 257-269页

作者： Wei ZHANG Tao WU Hong MA guixin li Department of Electronic and Optical Engineering Space Engineering University

In space information networks, satellites are generally in high speed orbit motion. In order to obtain better spacial and temporal coverage performance, satellites should cooperate with each other as a constellation. Previous works on constellations mainly focus on global seamless coverage using fewer satellites. However, like most countries, it is hard for China to build ground stations in overseas, and the geostationary Earth orbit position resource is scarce. In this paper, we investigate the constellation design problem with restricted ground supporting. We first proposes a 'backbone network + enhanced network' hybrid constellation design approach. Then a hybrid '4GEO+5IGSO' constellation is designed using the proposed approach, and the coverage performance of this constellation is analyzed in detail. Simulation results show the proposed approach can realize global seamless coverage only using a small number of satellites. Furthermore, the proposed hybrid constellation meets the coverage demand only relies on ground stations inside China.

关键词： space information network constellation design hybrid constellation GEO satellite IGSO satellite

Giant enhancement of second-harmonic generation from a nanocavity metasurface

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Science China(Physics,Mechanics & Astronomy) 2021年第9期64卷 75-81页

作者： Xuecai Zhang Junhong Deng Mingke Jin Yang li Ningbin Mao Yutao Tang Xuan liu Wenfeng Cai Yao Wang Kingfai li Yanjun liu guixin li Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China Materials Characterization and Preparation Center Southern University of Science and TechnologyShenzhen 518055China

Nonlinear plasmonic metasurfaces are compatible with complementary metal oxide semiconductor technology and highly promising for on-chip optical switching and modulations and nanoscale frequency ***,the low nonlinearoptical response of metasurface devices limits their practical *** circumvent this constraint,we propose the design of a nanocavity plasmonic metasurface,in which the strong light localization in the nanocavity can be used to boost the efficiency of second-harmonic *** with the single-layer counterpart,experimental results show that the intensity of the second-harmonic waves in the nanocavity metasurface is enhanced by~790 *** proposed nanocavity plasmonic metasurfaces in this work may open new routes for developing highly efficient nonlinear metacrystals for on-chip nonlinear sources,nonlinear image encryption,information processing,and so on.

关键词： metamaterials nonlinear optics nanostructures

Influence of Mass Ratio of Resin and Stabilizer on Mechanical Properties of Mo Fiber-reinforced Granite Polymer Composite

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 912-920页

作者：张超任秀华 BA Dongzhe ZHANG Jianhua li Jianyong GUO Mengnan GAO Yinghao WANG guixin li Jiayang School of Mechanical and Electronic Engineering Shandong Jianzhu UniversityJinan 250101China Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of Education of ChinaSchool of Mechanical EngineeringShandong UniversityJinan 250061China

Because inferior mechanical strength of granite polymer composite(GPC)has become the main drawback limiting its application and popularization,Mo fibers were added into(GPC)to improve its mechanical *** properties of matrix materials with different mass ratio of resin and stabilizer(MRRS)were investigated *** influences of MRRS on interface bonding strength of Mo fiber-matrix,wettability and mechanical strength of GPC were discussed,respectively,and the theoretical calculation result of MRRS k was obtained,with the optimal value of k=*** k=4,tensile strength,tensile strain and fracture stress of the cured resin achieve the maximum *** for k=7,the corresponding values reach the *** the increase of MRRS k,surface free energy of the cured resin first increases and then decreases,while contact angles between Mo sample and matrix have displayed the opposite *** of resin to Mo fiber is the best at k=*** load of Mo fiber and interface bonding strength appear the maximum at k=4,followed by k=5,k=3 the third,and k=7 the *** k=4,mechanical properties of Mo fiber-reinforced GPC are optimal,which is consistent with the result of theoretical *** study is of great significance to get better component formulas of Mo fiber reinforced GPC and to improve its application in machine tools.

关键词： polymer composite fiber mechanical strength interface bonding

Optical Orbital Angular Momentum: Thirty Years and Counting

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Advanced Photonics 2023年第3期5卷 22-22页

作者： guixin li Junsuk Rho Xiao-Cong Yuan Southern University of Science and Technology Shenzhen China Pohang University of Science and Technology(POSTECH)POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics Pohang Republic of Korea Shenzhen University College of Optoelectronics Nanophotonics Research Center ShenzhenChina

In 1992,Professor Allen’s paper published in Physical Review A indi-cated that laser light with a Laguerre-Gaussian amplitude distribution has an orbital angular momentum(OAM).Since then,conceptual stud-ies on OAM of photons have been attracting continual attention in physics and optics *** recent years,we have witnessed the birth and fast development of many break-through technologies driven by the concept of OAM,from advanced light-field manipulation to super-resolution imaging,classical and quantum optical communi-cations,and many others.

关键词： OAM Orbital attracting

Vectorial holography-mediated growth of plasmonic metasurfaces

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Science Bulletin 2021年第15期66卷 1518-1524,M0003页

作者： Zhen Yin Yue Shi Mengjia Cen Tun Cao Chunxiang Xu Dan Luo guixin li Yan-Jun liu Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China State Key Laboratory of Bioelectronics Southeast UniversityNanjing 210096China School of Optoelectronic Engineering and Instrumentation Science Dalian University of TechnologyDalian 116024China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Key Laboratory of Energy Conversion and Storage Technologies(Southern University of Science and Technology) Ministry of EducationShenzhen 518055China

Nowadays,the electromagnetic properties of artificial photonic materials can be well-tuned via designs over their composition and ***,engineering the properties of artificial materials at the nanoscale is challenging and *** we demonstrate a facile and low-cost method for fabricating large-area silver nanoparticle metasurfaces(AgNPMSs)by using the vectorial holography-mediated growth *** AgNPMS,which can be regarded as a hologram device,possesses excellent chiroptical *** vectorial holographic technique may open avenues for fabricating novel chiroptical metamaterials with large degrees of freedom,which can be further used for beam steering,photocatalysis,biosensing,etc.

关键词： Vectorial holography Plasmonics Metasurface Polarization Silver nanoparticle

Gigantic electric-field-induced second harmonic generation from an organic conjugated polymer enhanced by a band-edge effect

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light(Science & Applications) 2019年第1期8卷 1006-1011页

作者： Shumei Chen King Fai li guixin li Kok Wai Cheah Shuang Zhang School of Physics and Astronomy University of BirminghamBirmingham B152TTUK Department of Materials Science and Engineering Shenzhen Institute for Quantum Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China Department of Physics Hong Kong Baptist UniversityKowloon TongHong KongChina

Electric-field-induced second harmonic generation(EFISH),a third-order nonlinear process,arises from the interaction between the electric field of an external bias and that of two incident *** can be used to dynamically control the nonlinear optical response of materials and is therefore promising for active nonlinear ***,it has been challenging to achieve a strong modulation with EFISH in conventional nonlinear ***,we report a large tunability of an EFISH signal from a subwavelength-thick polymer film sandwiched between a transparent electrode and a metallic *** exploiting the band-edge-enhanced third-order nonlinear susceptibility of the organic conjugated polymer,we successfully demonstrate a gigantic EFISH effect with a modulation ratio up to 422%V^(−1) at a pumping wavelength of 840 *** band-edge-enhanced EFISH opens new avenues for modulating the intensity of SHG signals and for controlling nonlinear electro-optic interactions in nanophotonic devices.

关键词： nonlinear harmonic conjugated

Structural Engineering of Anode Materials for Low-Temperature lithium-Ion Batteries:Mechanisms,Strategies,and Prospects

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Nano-Micro Letters 2024年第8期16卷 169-195页

作者： Guan Wang guixin Wang linfeng Fei lina Zhao Haitao Zhang Beijing Key Laboratory of Ionic liquids Clean Process Institute of Process EngineeringChinese Academy of SciencesBeijing 100190People’s Republic of China School of Chemical Engineering Sichuan UniversityChengdu 610065People’s Republic of China School of Energy Materials and Chemical Engineering Hefei UniversityHefei 230601People’s Republic of China School of Materials Science and Engineering Nanchang UniversityNanchang 330031People’s Republic of China Key Laboratory of Polymer and Catalyst Synthesis Technology of liaoning Province School of Environmental and Chemical EngineeringShenyang University of TechnologyShenyang 110870People’s Republic of China

The severe degradation of electrochemical performance for lithium-ion batteries(liBs)at low temperatures poses a significant challenge to their practical ***,extensive efforts have been contributed to explore novel anode materials with high electronic conductivity and rapid li^(+)diffusion kinetics for achieving favorable low-temperature performance of ***,we try to review the recent reports on the synthesis and characterizations of low-temperature anode ***,we summarize the underlying mechanisms responsible for the performance degradation of anode materials at subzero ***,detailed discussions concerning the key pathways(boosting electronic conductivity,enhancing li^(+)diffusion kinetics,and inhibiting lithium dendrite)for improving the low-temperature performance of anode materials are ***,several commonly used low-temperature anode materials are briefly ***,recent progress in the engineering of these low-temperature anode materials is summarized in terms of structural design,morphology control,surface&interface modifications,and multiphase ***,the challenges that remain to be solved in the field of low-temperature anode materials are *** review was organized to offer valuable insights and guidance for next-generation liBs with excellent low-temperature electrochemical performance.

关键词： Low-temperature performance Anode materials Microstructural regulations Surface modifications