|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Ultrathin Acoustic Parity-Time Symmetric Metasurface Cloak显示文摘Invisibility or unhearability cloaks have been made possible by using metamaterials enabling light or sound to fow around obstacle without the trace of refections or shadows.Metamaterials are known for being fexible building units that can mimic a host of unusual and extreme material responses,which are essential when engineering artifcial material properties to realize a coordinate transforming cloak.Bending and stretching the coordinate grid in space require stringent material parameters;therefore,small inaccuracies and inevitable material losses become sources for unwanted scattering that are decremental to the desired efect.Tese obstacles further limit the possibility of achieving a robust concealment of sizeable objects from either radar or sonar detection.By using an elaborate arrangement of gain and lossy acoustic media respecting parity-time symmetry,we built a one-way unhearability cloak able to hide objects seven times larger than the acoustic wavelength.Generally speaking,our approach has no limits in terms of working frequency,shape,or size,specifcally though we demonstrate how,in principle,an object of the size of a human can be hidden from audible sound. | Hao-xiang Li Mar-a Rosendo-López Yi-fan Zhu Xu-dong Fan Daniel Torrent Bin Liang Jian-chun Cheng Johan Christensen | 2019 | Research2019，，1： | 4 |
| 2 | Hierarchicalzeolites: enhanced utilisation of microporous crystals in catalysis by advances in materialsdesign 显示文摘 | Perez - Ramirez Javier Christensen Claus H Groen Johan C | 2008 | Chemical Society Reviews2008，37，25： | 1 |
| 3 | Retreatment with peg-interferon and ribavirin in patients with chronic hepatitis C virus genotype 2 or 3 infection with prior relapse显示文摘 | Martin Lagging Karolina Rembeck Mads Rauning Buhl Peer Christensen Olav Dalgard Martti F?rkkil? Kristoffer Hellstrand Nina Langeland Magnus Lindh Johan Westin Gunnar Norkrans | 2013 | Scandinavian Journal of Gastroenterology2013，，7： | 1 |
| 4 | Subwavelength Acoustic Valley-Hall Topological Insulators Using Soda Cans Honeycomb Lattices显示文摘Topological valley-contrasting physics has attracted great attention in exploring the use of the valley degree of freedom as a promising carrier of information.Recently,this concept has been extended to acoustic systems to obtain nonbackscattering sound propagations.However,previous demonstrations are limited by the cut-of frequency of 2D waveguides and lattice-scale size restrictions since the topological edge states originate from Bragg interference.Here we engineer topologically valley-projected edge states in the form of spoof surface acoustic waves that confne along the surface of a subwavelength honeycomb lattice composed of 330-mL soda cans.Te inversion symmetry is broken through injecting a certain amount of water into one of the two cans in each unit cell,which gaps the Dirac cone and ultimately leads to the topological valley-Hall phase transition.Dual-frequency ranges of the valley-projected edge states below the sound line are observed,which originate from the frst-order and second-order resonances,respectively.Tese results have the potential to enable promising routes to design integrated acoustic devices based on valley-contrasting physics. | Zhiwang Zhang Ye Gu Houyou Long Ying Cheng Xiaojun Liu Johan Christensen | 2019 | Research2019，，1： | 0 |
| 5 | Theory of non-Hermitian topological whispering gallery显示文摘Topological insulators have taken the condensed matter physics scenery by storm and captivated the interest among scientists and materials engineers alike.Surprisingly,this arena which was initially established and profoundly studied in electronic systems and crystals,has sparked a drive among classical physicists to pursue a wave-based analogy for sound,light and vibrations.In the latest efforts combining valley-contrasting topological sound with non-Hermitian ingredients,B.Hu et al.[Nature 597,655(2021)]employed thermoacoustic coupling in sonic lattices whose elementary building blocks are coated with electrically biased carbon nanotube films.In this contribution,we take a theoretical and numerical route towards understanding the complex acoustic interplay between geometry and added acoustic gain as inspired by the aforesaid publication.Besides complex bulk and edge states predictions and computations of mode-split resonances using whispering gallery configurations,we also predict an acoustic amplitude saturation in dependence on the activated coated elements.We foresee that our computational advances may assist future efforts in exploring thermoacoustic topological properties. | RenéPernas-Salomón Li-Yang Zheng Zhiwang Zhang Penglin Gao Xiaojun Liu Ying Cheng Johan Christensen | 2022 | npj Computational Materials2022，，1： | 0 |
| 6 | 基于合成维度空间中深亚波长拓扑角态的声彩虹捕获显示文摘近年来,拓扑声学相关研究发展迅猛,其理论最初源于凝聚态物理中所发现的拓扑特性.其中,声学高阶拓扑绝缘体支持能量高度局域在拐角处的低维拓扑角态,且本征频率简并.然而,如何打破拓扑角态的多重简并,实现可调控的频率分布并设计新型声学多功能拓扑器件,是亟待解决的关键问题.在该研究中,通过对二维声子晶体中的单元施加平移形变,与真实空间自由度相结合构建四维合成空间.研究发现,随着平移形变自由度的调制,Zak相位连续变化,而合成空间的非零拓扑不变量确保了系统的非平庸拓扑特性,拓扑角态的频率简并被打破.基于此结论,进一步设计了基于合成维度的声学高阶拓扑绝缘体阵列,以实现局域在深亚波长拐角上的双通道声彩虹捕获.实验结果表明,不同通道上声彩虹拓扑角态的本征频率增加方向相反,在空间选择性能量捕获等领域具有潜在的应用前景. | 廖丹薇 刘翊贤 张志旺 程营 刘晓峻 Johan Christensen | 2023 | Science Bulletin2023，68，16： | 0 |
| 7 | 法罗群岛教育中心显示文摘格拉西尔坐落于法罗群岛起伏的峡湾上,坐拥大海和青翠的海湾景观,首都托尔斯港的景色一览无余。格拉西尔旨在把法罗群岛体育学校、托尔斯港技术学院和法罗群岛商学院合并在一起,提高整体效率,惠及1 750名师生和员工。通过创新孵化器的形式,不同于传统学校,格拉西尔既保留了三所学校的自主权,又为学校之间合作学习的蓬勃发展创造了理想条件。根据学生和教师的内部需求. | H■gni Laksáfoss Alberte Danvig Alejandro Mata Gonzales Alessio Valmori Alexandre Carpentier Annette Birthe Jensen Armen Menendian Athena Morella Baptiste Blot Boris Peianov Camille Crepin Claudio Moretti Dag Pr■stegaard Daniel Pihl David Zahle Edouard Boisse Elisha Nathoo Enea Michelesio Eskild Nordbud Ewelina Moszczynska Frederik Lyng Goda Luksaite Henrik Kania H■gni Laksáfoss Jakob Lange Jakob Teglg■rd Hansen Jan Besikov Jan Kudlicka Jan Magasanik Jeppe Ecklon Jesper Boye Andersen Ji-Young Yoon Johan Cool Kari-Ann Petersen Kim Christensen Kristoffer Negendahl Long Zuo Martin Cajade Michael Sch■nemann Jensen Mikkel Marcker Stubgaard Niklas Rausch Norbert Nadudvari Oana Simionescu Richard Howis Sabine Kokina Simonas Petrakas Sofia Sofianou Takumi Iwasawam Tobias Hjortdal Tommy Bj■rnstrup Victor Bejenaru Xiao Xuan Lu Rasmus Hjortshoj 曲鸿 | 2019 | 城市环境设计2019，0，2： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员