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Using coupling slabs to tailor surface-acoustic-wave band structures in phononic crystals consisting of pillars attached to elastic substrates

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Science China(Physics,Mechanics & Astronomy) 2017年第4期60卷 45-50页

作者： Heng Zhang SiYuan Yu fukang liu Zhen Wang MingHui Lu XiaoBo Hu YanFeng Chen XianGang Xu State Key Laboratory of Crystal Materials Shandong University National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering Nanjing University

The propagation of surface acoustic waves(SAWs) in two-dimensional phononic crystals(PnCs) with and without coupling-enhancement slabs was theoretically investigated using a three-dimensional finite element *** piezoelectric substrates,for example,lithium niobate(LiNbO_3),gallium nitride(GaN),and aluminium nitride(A1N),were taken into *** to the PnCs without coupling-enhancement slabs,the coupling between each pillar and its nearest neighbor was largely enhanced in the presence of *** bandwidth of the first directional band gap increased markedly compared with its initial value for the PnCs without a slab(within square symmetry).In addition,with increasing thicknesses of the slabs bonded between neighboring pillars,the first directional band-gap and second directional band gap of the PnCs tend to ***,the structure with coupling-enhancement slabs can be used as an excellent electrical band elimination filter for most electro-SAW devices,offering a new strategy to realize chip-scale applications in electroacoustic signal processing,optoacoustic modulation,and even SAW microfluidic devices.

关键词： surface acoustic waves(SAWs) phononic crystals(PnCs) tailored band structure

Stable,intense supercontinuum light generation at 1 kHz by electric field assisted femtosecond laser filamentation in air

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Light(Science & Applications) 2024年第2期13卷 354-365页

作者： Yaoxiang liu fukang Yin Tie-Jun Wang Yuxin Leng Ruxin Li Zhizhan Xu See Leang Chin State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics and CAS Center for Excellence in Ultra-intense Laser ScienceChinese Academy of SciencesShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Centre d’Optique Photonique et Laser(COPL)and Département de physiquede génie physique et d’optiqueUniversitéLavalQuébecQuébecCanada

Supercontinuum(SC)light source has advanced ultrafast laser spectroscopy in condensed matter science,biology,physics,and *** to the frequently used photonic crystal fibers and bulk materials,femtosecond laser filamentation in gases is damage-immune for supercontinuum generation.A bottleneck problem is the strong jitters from filament induced self-heating at kHz repetition rate *** demonstrated stable kHz supercontinuum generation directly in air with multiple mJ level pulse *** was achieved by applying an external DC electric field to the air plasma *** pointing jitters of the 1 kHz air filament induced SC light were reduced by more than 2 *** stabilized high repetition rate laser filament offers the opportunity for stable intense SC generation and its applications in air.

关键词： intense repetition light

Moderate Fields, Maximum Potential: Achieving High Records with Temperature‑Stable Energy Storage in Lead‑Free BNT‑Based Ceramics

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Nano-Micro Letters 2024年第5期16卷 184-200页

作者： Wenjing Shi Leiyang Zhang Ruiyi Jing Yunyao Huang fukang Chen Vladimir Shur Xiaoyong Wei Gang liu Hongliang Du Li Jin Electronic Materials Research Laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China School of Materials and Energy Southwest UniversityChongqing 400715People’s Republic of China School of Natural Sciences and Mathematics Ural Federal UniversityEkaterinburg 620000Russia Multifunctional Electronic Ceramics Laboratory College of EngineeringXi’an International UniversityXi’an 710077People’s Republic of China

The increasing awareness of environmental concerns has prompted a surge in the exploration of leadfree,high-power ceramic *** efforts to develop leadfree dielectric ceramics with exceptional energystorage performance(ESP)have predominantly relied on multicomponent composite strategies,often accomplished under ultrahigh electric ***,this approach poses challenges in insulation and system downsizing due to the necessary working voltage under such *** extensive study,bulk ceramics of(Bi_(0.5)Na_(0.5))TiO_(3)(BNT),a prominent lead-free dielectric ceramic family,have seldom achieved a recoverable energy-storage(ES)density(Wrec)exceeding 7 J cm^(−3).This study introduces a novel approach to attain ceramic capacitors with high ESP under moderate electric fields by regulating permittivity based on a linear dielectric model,enhancing insulation quality,and engineering domain structures through chemical formula *** incorporation of SrTiO_(3)(ST)into the BNT matrix is revealed to reduce the dielectric constant,while the addition of Bi(Mg_(2/3)Nb_(1/3))O_(3)(BMN)aids in maintaining ***,the study elucidates the methodology to achieve high ESP at moderate electric fields ranging from 300 to 500 kV cm^(−1).In our optimized composition,0.5(Bi_(0.5)Na_(0.4)K_(0.1))TiO_(3)–0.5(2/3ST-1/3BMN)(B-0.5SB)ceramics,we achieved a Wrec of 7.19 J cm^(−3) with an efficiency of 93.8%at 460 kV cm^(−1).Impressively,the B-0.5SB ceramics exhibit remarkable thermal stability between 30 and 140℃ under 365 kV cm^(−1),maintaining a Wrec exceeding 5 J cm^(−3).This study not only establishes the B-0.5SB ceramics as promising candidates for ES materials but also demonstrates the feasibility of optimizing ESP by modifying the dielectric constant under specific electric field ***,it provides valuable insights for the future design of ceramic capacitors with high ESP under constraints of limited electric field.

关键词： BNT Energy storage Lead-free Relaxor ferroelectrics Capacitors

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皮秒激光铝合金黑色标刻实验与理论建模分析

激光与光电子学进展 2023年第23期60卷 211-217页

作者：刘福康李建美山东大学机械工程学院高效洁净机械制造教育部重点实验室山东济南250061

使用皮秒激光时,通过改变激光标刻参数,可以在铝合金表面得到不同对比度的黑色图案。通过激光扫描显微镜对实验标刻样本表面进行测量,并通过电磁波理论建模对皮秒激光打黑机理进行分析。研究发现,激光标刻样本宏观基体表面存在微纳尺度... 详细信息

使用皮秒激光时,通过改变激光标刻参数,可以在铝合金表面得到不同对比度的黑色图案。通过激光扫描显微镜对实验标刻样本表面进行测量,并通过电磁波理论建模对皮秒激光打黑机理进行分析。研究发现,激光标刻样本宏观基体表面存在微纳尺度的最大高度值不同的密集峰谷形貌。样本表面微纳峰谷形貌的最大高度值越大,表面反射率越低,从而形成对比度较大的黑色图案。通过样本灰度值得到的对比度与理论建模得到的对比度几乎一致,这证实上述机理是激光打黑铝合金的主要原因。

关键词：皮秒激光标刻黑色图案反射率对比度电磁波

Construction of Photoresponsive 3D Structures Based on Triphenylethylene Photochromic Building Blocks

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Research 2022年第4期2022卷 87-96页

作者： Xiayu Zhang fukang liu Beibei Du Rongjuan Huang Simin Zhang Yunfei He Hailan Wang Jingjing Cui Biao Zhang Tao Yu Wei Huang Frontiers Science Center for Flexible Electronics Shaanxi Institute of Flexible Electronics Shaanxi Institute of Biomedical Materials and EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi'an 710072China Key Laboratory of Flexible Electronics e Institute of Advanced Materials Nanjing Tech University30 South Puzhu RoadNanjing211816China State Key Laboratory of Organic Electronics and Information Displays e Institute of Advanced Materials(IAM) Nanjing University of Posts Telecommunications9 Wenyuan RoadNanjing 210023China

Photoresponsive materials have been widely used in sensing,bioimaging,molecular switches,information storage,and encryption *** a large amount of photoresponsive materials have been reported,the construction of these smart materials into precisely prescribed complex 3D geometries is rarely *** we designed a novel photoresponsive material methyl methacrylate containing triphenylethylene(TrPEF_(2)-MA)that can be directly used for digital light processing(DLP)3D *** on TrPEF_(2)-MA,a series of photoresponsive 3D structures with reversible color switching under ultraviolet/visible light irradiations were *** complex photoresponsive 3D structures show high resolutions(50μm),excellent repeatability(25 cycles without fatigue),and tunable saturate color *** DLP 3D printing processes were also carried out to demonstrate their great properties in information hiding and information-carrying *** design strategy for constructing photoresponsive 3D structures is attractive in the area of adaptive camouflage,information hiding,information storage,and flexible electronics.

关键词： properties prescribed attractive

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对宝石光学效果的研究及评价

中国宝玉石 2020年第1期 44-51页

作者：刘富康中国地质大学(北京)珠宝学院北京100083

宝石的光学效果主要包括颜色、亮度、火彩、闪烁等,除了宝石本身的性质,观察的位置、光线的明暗、背景的图案等也会对宝石的光学效果产生影响.在评价宝石颜色过程中,可使用比色石或者GemSet、GemDialogue以及Munsell色卡与宝石比色,对... 详细信息

宝石的光学效果主要包括颜色、亮度、火彩、闪烁等,除了宝石本身的性质,观察的位置、光线的明暗、背景的图案等也会对宝石的光学效果产生影响.在评价宝石颜色过程中,可使用比色石或者GemSet、GemDialogue以及Munsell色卡与宝石比色,对其质量做出半定量评价;可使用Color i5测色仪、X-riteI5分光光度仪、Color Eye7000A测色仪、USB2000光纤光谱仪测量宝石的明度、色相、饱和度、彩度、色纯度、色度坐标、主波长等颜色参数,通过比较各个参数之间的关系对其颜色质量进行评价,还可以利用色差公式展开进一步的讨论.为最大限度展现宝石的美,宝石学家发明了一系列不同类型的切割方式,传统的圆明亮型切割的切割比例可以达到较好的光学表现效果,但是根据不同的需求,可对宝石的比例做出轻微调整.对宝石光学效果的研究方法主要有两种,一种是通过光线追踪,另一种是通过摄影技术,对宝石的图像特征进行研究.测量宝石光学效果的仪器主要有Fire Scope、ASET instrument、Brilliance Scope、Diamond Integrator、钻石光学效果观察仪等.

关键词：光学效果宝石光线追踪评价方法

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大型仪器在彩色钻石颜色成因研究中的应用

中国宝玉石 2021年第S1期 54-60页

作者：刘富康中国地质大学(北京)珠宝学院

彩色钻石通常含有杂质或结构上的缺陷,每种杂质和缺陷选择性吸收不同波长的光,从而产生不同的肉眼可见的颜色。目前,对彩色钻石的颜色成因进行探测的大型仪器主要包括傅里叶变换红外光谱仪、紫外—可见分光光度计、紫外荧光灯和光纤光... 详细信息

彩色钻石通常含有杂质或结构上的缺陷,每种杂质和缺陷选择性吸收不同波长的光,从而产生不同的肉眼可见的颜色。目前,对彩色钻石的颜色成因进行探测的大型仪器主要包括傅里叶变换红外光谱仪、紫外—可见分光光度计、紫外荧光灯和光纤光谱仪等。红外光谱可以检测到A型氮、B型氮、孤立氮、硼以及氢;紫外—可见分光光度计可以测量到N3中心、N2中心、H3中心以及与氮空位或者氢相关的吸收;钻石的荧光颜色为白垩蓝色、绿色,极少数是红色或橘红色;使用GEM 3000型光纤光谱仪在近液氮温度下可测试N3中心、H4中心、H3中心、NV;中心、NV;中心、GR1中心以及H2中心等处的PL峰。大型仪器的测试结果可以为探究钻石颜色成因提供理论依据。

关键词：彩色钻石红外光谱仪紫外—可见分光光度计紫外荧光灯光纤光谱仪