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Merging bound states in the continuum by harnessing higher-order topological charges

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Light(Science & Applications) 2022年第9期11卷 2098-2106页

作者： Meng Kang Li Mao Shunping Zhang Meng Xiao Hongxing Xu che ting chan School of Physics and Technology and Key Laboratory of Artificial Micro-and Nano-structures of Ministry of EducationWuhan UniversityWuhan 430072China Department of Physics The Hong Kong University of Science and TechnologyHong KongChina Wuhan Institute of Quantum Technology Wuhan 430206China School of Microelectronics Wuhan UniversityWuhan 430072China

Bound states in the continuum(BICs)can confine light with a theoretically infinite Q ***,in practical on-chip resonators,scattering loss caused by inevitable fabrication imperfection leads to finite Q factors due to the coupling of BICs with nearby radiative *** multiple BICs can improve the robustness of BICs against fabrication imperfection by improving the Q factors of nearby states over a broad wavevector *** date,the studies of merging BICs have been limited to fundamental BICs with topological charges±*** we show the unique advantages of higher-order BICs(those with higher-order topological charges)in constructing merging *** multiple BICs with a higher-order BIC can further improve the Q factors compared with those involving only fundamental *** addition,higher-order BICs offer great flexibility in realizing steerable off-T merging BICs.A higher-order BIC at F can split into a few off-T fundamental BICs by reducing the system *** split BICs can then be tuned to merge with another BIC,e.g.,an accidental BIC,at an off-Γ*** the in-plane mirror symmetry is further broken,merging BICs become steerable in the reciprocal *** BICs provide a paradigm to achieve robust ultrahigh-Q resonances,which are important in enhancing nonlinear and quantum effects and improving the performance of optoelectronic devices.

关键词： topological charges states

Momentum-space polarization fields in two-dimensional photonic-crystal slabs:Physics and applications

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Chinese Physics B 2022年第10期31卷 23-33页

作者： Wen-Zhe Liu Lei Shi che-ting chan Jian Zi Department of Physics The Hong Kong University of Science and TechnologyHong Kong 999077China State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education)and Department of PhysicsFudan UniversityShanghai 200433China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

In addition to non-radiative guided modes, two-dimensional photonic-crystal slabs support guided resonant ones which can radiate into free space. From the polarization states of these guided resonances, a polarization field on a photonic band can be constructed in momentum space. Momentum-space polarization fields display complicated configurations and patterns with different types of polarization singularities inside, shedding new light on the manipulations of light *** this review, we summarize the recent research progress on momentum-space polarization fields and singularities in two-dimensional photonic-crystal slabs, focusing on their unique optical properties and potential applications as well.

关键词： photonic crystal polarization field polarization singularity

Experimental realization of chiral Landau levels in two-dimensional Dirac cone systems with inhomogeneous effective mass

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Light(Science & Applications) 2023年第8期12卷 1616-1622页

作者： Hongwei Jia Mudi Wang Shaojie Ma Ruo-Yang Zhang Jing Hu Dongyang Wang che ting chan Department of Physics the Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Institute for Advanced Study the Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Department of Physics University of Hong KongHong KongChina

Chiral zeroth Landau levels are topologically protected bulk *** particle physics and condensed matter physics,the chiral zeroth Landau level plays a significant role in breaking chiral symmetry and gives rise to the chiral *** experimental works on such chiral Landau levels are mainly based on three-dimensional Weyl degeneracies coupled with axial magnetic *** realizations using two-dimensional Dirac point systems,being more promising for future applications,were never experimentally realized *** we propose an experimental scheme for realizing chiral Landau levels in a two-dimensional photonic *** introducing an inhomogeneous effective mass through breaking local parity-inversion symmetries,a synthetic in-plane magnetic field is generated and coupled with the Dirac ***,the zeroth-order chiral Landau levels can be induced,and the one-way propagation characteristics are experimentally *** addition,the robust transport of the chiral zeroth mode against defects in the system is also experimentally *** system provides a new pathway for the realization of chiral Landau levels in two-dimensional Dirac cone systems,and may potentially be applied in device designs utilizing the chiral response and transport robustness.

关键词： chiral Landau realization

Acoustic metamaterials with negative and zero refractive indices

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Acoustic metamaterials with negative and zero refractive ind...

Human endogenous retrovirus type-W and multiple sclerosis–related smoldering neuroinflammation

2011年全国压电和声波理论及器件应用研讨会

作者： che ting chan Hong Kong University of Science and Technology,Clear Water Bay.Hong Kong

＜正＞Acoustic metamaterials are composite materials in which the effective density and bulk modulus can be tuned by using resonating units embedded inside a host,and the effective values of density and bulk modulus are discussed in the sense of an effective medium *** the technique of transformation optics,we will show that acoustic metamaterials can achieve novel wave manipulation effects such as invisible *** cloaking effect can be achieved using acoustic metamaterials that either enclose or do not enclose the object to be cloaked. In particular,if acoustic metamaterials with negative modulus and negative density are available,we can do "remote cloaking",in the sense that we can make an object undetectable without touching it.

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Neural Regeneration Research 2025年第3期20卷 813-814页

作者： Joel Gruchot Laura Reiche Andrew chan Robert Hoepner Patrick Küry Department of Neurology Medical Faculty and University Hospital DüsseldorfHeinrich Heine University DüsseldorfDüsseldorfGermany Department of Neurology InselspitalBern University Hospital and University of BernBernSwitzerland

Introduction to human endogenous retrovirus type-W(HERV-W): Genomic inheritance from the past includes retroviral sequences that have been stably incorporated into our genomes and account for up to 8% of human DNA.

关键词： endogenous inflammation Human

Convergence Rate for Galerkin Approximation of the Stochastic Allen–Cahn Equations on 2D Torus

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Acta Mathematica Sinica,English Series 2021年第3期37卷 471-490页

作者： ting MA Rong chan ZHU College of Mathematics Sichuan UniversityChengdu 610065P.R.China Department of Mathematics Beijing Institute of TechnologyBeijing 100081P.R.China Department of Mathematics University of BielefeldD-33615 BielefeldGermany

In this paper we discuss the convergence rate for Galerkin approximation of the stochastic Allen–Cahn equations driven by space-time white noise on T^(2). First we prove that the convergence rate for stochastic 2D heat equation is of order α-δ in Besov space C^(-α) for α∈(0, 1) and δ > 0 arbitrarily small. Then we obtain the convergence rate for Galerkin approximation of the stochastic Allen–Cahn equations of order α-δ in C^(-α) for α∈(0, 2/9) and δ > 0 arbitrarily small.

关键词： Stochastic Allen–Cahn equations convergence rate Galerkin projection Besov space white noise

Acrosome reaction in the cumulus oophorus revisited:involvement of a novel sperm-released factor NYD-SP8

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Protein & Cell 2011年第2期2卷 92-98页

作者： ting ting Sun Chin Man Chung Hsiao chang chan Epithelial Cell Biology Research Center School of Biomedical SciencesFaculty of MedicineThe Chinese University of Hong KongHong KongChina

Fertilization is a process involving multiple steps that lead to the final fusion of one sperm and the oocyte to form the *** of the steps,acrosome reaction(AR),is an exocytosis process,during which the outer acrosome membrane fuses with the inner sperm membrane,leading to the release of acrosome enzymes that facilitate sperm penetration of the egg *** AR has been investigated for decades,the initial steps of AR in vivo,however,remain largely unknown.A well elucidated model holds the view that AR occurs on the surface of the zona pellucida(ZP),which is triggered by binding of sperm with one of the ZP glycosylated protein,***,this model fails to explain the large number of‘falsely’acrosome-reacted sperms found within the cumulus layer in many species *** the emerging evidence of cross-talk between sperm and cumulus cells,the potential significance of AR in the cumulus oophorus,the outer layer of the egg,has been gradually *** we review the acrosome status within the cumulus layer,the cross-talk between sperm and cumulus cells with the involvement of a novel spermreleased factor,NYD-SP8,and re-evaluate the importance and physiological significance of the AR in the cumulus in fertilization.

关键词： sperm acrosome reaction cumulus NYP-SP8 progesterone

Toward haplotype studies in polyploid plants to assist breeding

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Molecular Plant 2021年第12期14卷 1969-1972页

作者： Yuxuan Yuan Armin Scheben David Edwards ting-Fung chan School of Life Sciences and State Key Laboratory of Agrobiotechnology The Chinese University of Hong KongHong Kong SARChina Simons Center for Quantitative Biology Cold Spring Harbor LaboratoryCold Spring HarborNYUSA School of Biological Sciences and Institute of Agriculture The University of Western AustraliaPerthAustralia

THE IMPORTANCE OF POLYPLOIDS Polyploids are typically classified as either autopolyploids or allo-polyploids(Figure 1).Autopolyploids result from whole-genome duplication within the same species,while allopolyploids derive from the hybridization of different species followed by chromo-some ***,plant allopolyploids are thought to be the most common polyploids,although autopolyploid plants and allopolyploid plants might be at parity in numbers(Barker et al.,2016).During speciation,polyploidization allows plants to adapt to different environments(Soltis et al.,2009).Mutation and hybridization increase the heterozygosity of the genome,while genome rearrangements during polyploidization lead to the formation of new chromosomes and new chromosome rearrangements,which complicate polyploid genomes and the following studies.

关键词： breeding Figure

Ion channels/transporters as epigenetic regulators?——a microRNA perspective

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Science China(Life Sciences) 2012年第9期55卷 753-760页

作者： JIANG XiaoHua ZHANG Jie ting chan Hsiao chang Epithelial Cell Biology Research Center School of Biomedical Sciences Faculty of Medicine The Chinese University of Hong Kong Shatin Hong Kong China Key Laboratory for Regenerative Medicine Jinan University-The Chinese University of Hong Kong Ministry of Education of China Guang- zhou 510632 China Sichuan University-The Chinese University of Hong Kong Joint Laboratory for Reproductive Medicine West China Women and Childern's Hospital Chengdu 610041 China

MicroRNA （miRNA） alterations in response to changes in an extracellular microenvironment have been observed and consid- ered as one of the major mechanisms for epigenetic modifications of the cell. While enormous efforts have been made in the understanding of the role of miRNAs in regulating cellular responses to the microenvironment, the mechanistic insight into how extracellular signals can be transduced into miRNA alterations in cells is still lacking. Interestingly, recent studies have shown that ion channels/transporters, which are known to conduct or transport ions across the cell membrane, also exhibit changes in levels of expression and activities in response to changes of extraceUular microenvironment. More importantly, al- terations in expression and function of ion channels/transporters have been shown to result in changes in miRNAs that are known to change in response to alteration of the microenvironment. In this review, we aim to summarize the recent data demonstrating the ability of ion channels/transporters to transduce extracellular signals into miRNA changes and propose a potential link between cells and their microenvironment through ion channels/transporters. At the same time, we hope to pro- vide new insights into epigenetic regulatory mechanisms underlying a number of physiological and pathological processes, in- eluding embryo development and cancer metastasis.

关键词： ion channel miRNAs epigenetic microenvironment