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Theoretical study of broadband near-field optical spectrum of twisted bilayer graphene

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Frontiers of physics 2022年第4期17卷 67-74页

作者： Lu Wen Yijun Liu Guoyu Luo xinyu lv Kaiyuan Wang Wang Zhu Lei Wang Zhiqiang Li College of Physics Sichuan UniversityChengdu 610064China National Laboratory of Solid-State Microstructures School of PhysicsNanjing UniversityNanjing 210093China

We theoretically study the broadband near-field optical spectrum of twisted bilayer graphene(TBG)at various twist angles near the magic angle using two different models.The spectrum at low Fermi energy is characterized by a series of peaks that are almost at the same energies as the peaks in the far-field optical conductivity of TBG.When the Fermi energy is near a van Hove singularity,an additional strong peak appears at finite energy in the near-field spectrum,which has no counterpart in the optical conductivity.Based on a detailed calculation of the plasmon dispersion,we show that these spectroscopic features are associated with interband and intraband plasmons,which can provide critical information about the local band structure and plasmonic excitations in TBG.The near-field peaks evolve systematically with the twist angle,so they can serve as fingerprints for identifying the spatial dependent twist angle in TBG samples.Our findings pave the way for future experimental studies of the novel optical properties of TBG in the nanoscale.

关键词： twisted bilayer graphene SNOM broadband near-field optical spectrum,optical conductivity magic angle

Strain induced topological transitions in twisted double bilayer graphene

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Frontiers of physics 2022年第2期17卷 89-97页

作者： Guoyu Luo xinyu lv Lu Wen Zhiqiang Li Zhenbing Dai College of Physics Sichuan UniversityChengdu 610064China Department of Physics Sichuan Normal UniversityChengdu 610066China

We theoretically study the band structures and the valley Chern numbers of the AB-AB and AB-BA stacked twisted double bilayer graphene under heterostrain effect.In the absence of heterostrain,due to the constrains by the spatial symmetries,the central two flat bands of the AB-AB are topological trivial bands,while in the AB-BA they have a finite Chern number.The heterostrain breaks all the point group symmetries and the constrains are lifted,hence the topological properties of the two arrangements can be tuned by different strain magnitudesεand directionsφ.The heterostrain has dissimilar impacts on the Chern numbers of the AB-AB and AB-BA,owing to their different band gaps,and these gaps can be modified by a vertical electric field.Our results show that the topological transitions for both arrangements occur in theεrange of 0.1%-0.4%,which can be realized in the graphene-based sample.

关键词： valley Chern number twisted double bilayer graphene flat bands heterostrain

Near-field infrared response of graphene on copper substrate

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Frontiers of physics 2022年第4期17卷 75-81页

作者： Zhen-Bing Dai Gui Cen Zhibin Zhang xinyu lv Kaihui Liu Zhiqiang Li College of Physics Sichuan UniversityChengdu 610065China School of Physics Peking UniversityBeijing 100871China Department of Physics Sichuan Normal UniversityChengdu 610066China

The electronic properties of graphene are very sensitive to its dielectric environment.The coupling to a metal substrate can give rise to many novel quantum effects in graphene,such as band renormalization and plasmons with unusual properties,which are of high technological interest.Infrared nanoimaging are very suitable for exploring these effects considering their energy and length scales.Here,we report near-field infrared nanoimaging studies of graphene on copper synthesized by chemical vapor deposition.Remarkably,our measurements reveal three different types of near-field optical responses of graphene,which are very distinct from the near-field edge fringes observed in the substrate.These results can be understood from the modification of optical conductivity of graphene due to its coupling with the substrate.Our work provides a framework for identifying the near-field response of graphene in graphene/metal systems and paves the way for studying their novel physics and potential applications.

关键词： near-field infrared response graphene copper graphene/metal

环境规制下我国绿色产学研推进路径研究——基于重污染企业的数据检验

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大庆师范学院学报 2024年第2期44卷 47-53页

作者：李博吕馨宇周建亚乐山师范学院国有资产管理处四川乐山614000 昆明理工大学城市学院云南昆明650000 江苏大学管理学院江苏镇江212013

产学研是推动我国科技创新的重要手段,而绿色产学研现已成为产学研发展的主流。环境规划是绿色产学研发展的重要驱动力量,重污染企业绿色产学研可以推进我国绿色产学研的发展。基于我国重污染企业产学研的样本数据,实证性检验揭示了命... 详细信息

产学研是推动我国科技创新的重要手段,而绿色产学研现已成为产学研发展的主流。环境规划是绿色产学研发展的重要驱动力量,重污染企业绿色产学研可以推进我国绿色产学研的发展。基于我国重污染企业产学研的样本数据,实证性检验揭示了命令控制型环境规制和市场激励型环境规制对绿色产学研的驱动机理,提出绿色产学研推进路径,为我国绿色产学研发展提供理论借鉴。研究表明,在我国当前的环境规制下,绿色产学研将在如下方向大力推进:充分发挥市场激励型环境规制对绿色产学研的促进作用;加大企业在绿色产学研中的绿色参与力度;高校和科研机构应积极发挥对企业绿色行为的引导和监督作用;不能过度依赖命令控制型环境规制对绿色产学研推进的短期效应。

关键词：绿色产学研环境规制重污染企业命令控制型企业方绿色参与

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Discussion on Reverse Design of Components with Complex Curved Surface and Computer Numerical Control Machining

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Journal of Electronic Research and Application 2018年第4期2卷 14-18页

作者： Dapeng Fu xinyu lv Shuangyang Jiang Northeast Electric Power University Jilin 132012China

With the continuous development and advancement of science and technology,the work of tool path planning has received extensive attention.Among them,curved surface generation and data processing are the focus of management and design,which necessitate the full application of reverse design of complex curved surface components to complete numerical control processing,effective optimization and upgrading,integration the tasks of point cloud data collection,and point cloud data processing to ensure that the corresponding computer numerical control machining model can exert its actual value.This paper briefly analyzes the basic principles of curved surface reconstruction as well as discusses the reverse design of complex curved components and the experimental processes and results that involved computer numerical control machining,which serves the purpose as reference only.

关键词： complex curved surface component reverse design computer numerical control machining

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燃气用具连接用软管的强制性国家标准解读

城市燃气 2024年第6期 20-26页

作者：张梦婷渠艳红李军王洪林吕昕宇中国市政工程华北设计研究总院有限公司

本文说明了燃气用具连接用软管的三项强制性国家标准GB41317-2024[1]《燃气用具连接用不锈钢波纹软管》、GB44017-2024[2]《燃气用具连接用金属包覆软管》与GB44023-2024[3]《燃气用具连接内用橡胶复合软管》的发布背景和目的,并分别对... 详细信息

本文说明了燃气用具连接用软管的三项强制性国家标准GB41317-2024[1]《燃气用具连接用不锈钢波纹软管》、GB44017-2024[2]《燃气用具连接用金属包覆软管》与GB44023-2024[3]《燃气用具连接内用橡胶复合软管》的发布背景和目的,并分别对比了GB41317-2024与GB/T41317-2022[4]、GB44017-2024与CJ/T490-2016[5]、GB44023-2024与CJ/T 491-2016[6]的技术内容差异及其解读。

关键词： GB41317-2024 GB44017-2024 GB44023-2024 标准解读

Research on microstructure in as-cast 7A55 aluminum alloy and its evolution during homogenization

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Rare Metals 2011年第6期30卷 664-668页

作者： lv xinyu GUO Erjun LI Zhihui WANG Guojun The School of Materials Science and Engineering Harbin University of Science and Technology Harbin 150080 China Northeast light alloy Co. Ltd. Harbin 150060 China State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous Metals Beijing 100088 China

The microstructure of the as-cast 7A55 aluminum alloy and its evolution during homogenization were investigated by means of optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC） analysis. The results indicate that the microstructure of the as-cast 7A55 aluminum alloy mainly consists of the dendritic network of aluminum solid solution, Al/AIZnMgCu eutectic phases, and intermetaUic compounds MgZn2, Al2CuMg, Al7Cu2Fe, and Al23CuFe4. After homogenization at 470℃ for 48 h, Al/AlZnMgCu eutectic phases are dissolved into the matrix, and a small amount of high melting-point secondary phases were formed, which results in an increasing of the starting melting temperature of 7A55 aluminum alloy The high melting-point secondary phases were eliminated mostly when the homogenization time achieved to 72 h. Therefore, the reasonable homogenization heat treatment process for 7A55 aluminum alloy ingots was chosen as 470℃/72 h.

关键词： 7A55 aluminum alloy as-cast constituents homogenization

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Utilizing dual-pathway energy transfer in upconversion nanoconjugates for reinforced photodynamic therapy

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Nano Research 2024年第4期17卷 2941-2948页

作者： Ruohao Zhang Yu Lu Yifei Zhou Kehong lv xinyu Fu Jitong Gong Shuang Yao Xiaozhen Wang Jing Feng Hongjie Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China College of Chemistry Jilin UniversityChangchun 130012China Department of Breast Surgery General Surgery Centerthe First Hospital of Jilin UniversityChangchun 130021China Department of Chemistry Tsinghua UniversityBeijing 100084China

Enhancing the therapeutic effect of existing treatments or developing new non-invasive treatments are important measures to achieve high-efficiency treatment of malignant tumors.Photodynamic therapy(PDT)is an emerging treatment modality,and the key for achieving high-efficiency PDT is to select light with strong tissue penetration depth and enhance the generation of reactive oxygen species(ROS).Although the upconversion nanoparticles(UCNPs)modified with the photosensitizers could achieve PDT with strong penetration depth under near-infrared light irradiation,the ROS generated by traditional single-pathway PDT is still insufficient.Herein,we developed a novel nanoconjugate(UCNP-Ce6/AIEgen)for dual-pathway reinforced PDT,in which the UCNPs were co-modified with chlorin e6(Ce6)and luminogen with aggregation-induced emission(AIEgen).Due to the presence of AIEgen,UCNP-Ce6/AIEgen could avoid aggregation-caused luminescence quenching in biological water environments and convert upconversion luminescence(UCL)of UCNPs to Ce6-activatable fluorescence.Therefore,under the irradiation of 808 nm laser,UCNP-Ce6/AIEgen can not only undergo direct lanthanide-triplet energy transfer to activate Ce6,but also convert the UCL of UCNPs to the light that can activate Ce6 through Fӧrster resonance energy transfer to generate more ROS,thus promoting tumor cell apoptosis.This work broadens the applications of nanoconjugates of lanthanide-based inorganic materials and organic dyes,and provides a conception for reinforced PDT of tumors.

关键词： upconversion nanoparticle aggregation-induced emission direct lanthanide-triplet energy transfer Förster resonance energy transfer photodynamic therapy

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聚合物平面光波导器件的研究进展

半导体光电 2022年第2期43卷 316-326页

作者：吕昕雨尹悦鑫李悦张大明吉林大学电子科学与工程学院集成光电子学国家重点实验室长春130012

聚合物平面光波导(PLC)器件以其低损耗、低成本、低功耗,以及制备工艺简单等优点,在光通信网络、微波光子学、传感监控等领域发挥着重要作用。文章梳理了近年来聚合物平面光波导器件的代表性工作,其中包括阵列波导光栅、可变光衰减器、... 详细信息

聚合物平面光波导(PLC)器件以其低损耗、低成本、低功耗,以及制备工艺简单等优点,在光通信网络、微波光子学、传感监控等领域发挥着重要作用。文章梳理了近年来聚合物平面光波导器件的代表性工作,其中包括阵列波导光栅、可变光衰减器、光开关及其集成器件,讨论了聚合物平面光波导未来的发展方向。

关键词：聚合物波导器件集成光学阵列波导光栅光开关

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