Article
Chemistry, Multidisciplinary
Qiumeng Qin, Jianfeng Chen, Hao Lin, Chaoqun Peng, Zhi-Yuan Li
Summary: We propose and realize a new configuration of a photonic Chern topological insulator (PCTI) in which five distinct types of edges allow the propagation of truly one-way edge states. We design topological transmission lines with sharp turns using this special PCTI, leading to topological resistance-free one-way transport.
Article
Physics, Multidisciplinary
Chaoqun Peng, Jianfeng Chen, Qiumeng Qin, Zhi-Yuan Li
Summary: This paper presents a theoretical and numerical demonstration of topological one-way edge states in an air-hole honeycomb gyromagnetic photonic crystal. These states, localized to the edge and confined vertically by parallel metallic plates, exhibit robust one-way propagation characteristics. They are resistant to defects and imperfections, and can even propagate unidirectionally along irregular edges of arbitrary geometries.
FRONTIERS IN PHYSICS
(2022)
Article
Physics, Multidisciplinary
Yu Wang, Hao Lin, Jianfeng Chen, Yidong Zheng, Zitao Ji, Zhi-Yuan Li
Summary: This paper proposes a novel method to construct unidirectional 2D waveguides with larger area of energy transmission in 3D space. A 2D one-way interface transmission channel is designed and the topological phase transition between Weyl phase and 3D Chern insulator phase is studied, providing more possibilities for topological regulation of the surface states.
SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
(2023)
Article
Physics, Multidisciplinary
Jianfeng Chen, Zhi-Yuan Li
Summary: We report a two-dimensional heterogeneous Haldane model and predict the emergence of robust one-way bulk states by theoretical calculation. Through numerical simulations and experimental measurements, we confirm the existence of these robust states in a two-dimensional microwave gyromagnetic photonic crystal.
PHYSICAL REVIEW LETTERS
(2022)
Review
Physics, Multidisciplinary
Jianfeng Chen, Zhi-Yuan Li
Summary: This paper reviews the fundamental physics, novel properties, and practical applications of topological photonic states (TPSs) based on gyromagnetic photonic crystals (GPCs). Various types of TPSs are examined, and the coupling effect between TPSs is discussed. Future development trends are also analyzed.
Article
Materials Science, Multidisciplinary
Yongqi Chen, Nan Gao, Guodong Zhu, Yurui Fang
Summary: This study explores a hexagonal cavity that supports chiral topological whispering gallery (CTWG) modes formed by a gyromagnetic photonic crystal. Simulation results demonstrate the presence of discrete edge states within the topological band gap, showcasing the cavity's immunity to interference and its effectiveness in maintaining CTWG modes under various perturbations.
Article
Biophysics
Kevin Li, Liliya A. Yatsunyk, Stephen Neidle
Summary: Left-handed G quadruplexes (LHG4) have been discovered as a new type of G quadruplexes. Our study demonstrates that specific backbone torsion angles can differentiate between right-handed and left-handed G quadruplexes as well as other DNA structures. This analysis provides insights into the conditions of formation for LHG4s and their potential biological relevance.
BIOPHYSICAL JOURNAL
(2022)
Article
Materials Science, Multidisciplinary
Ye Tian, Qian Shen, Yun You, Linfang Shen
Summary: The study investigates a photonic crystal with a large band gap and nontrivial topological property, which can achieve different one-way modes immune to backscattering by interfacing with cladding materials with different topological properties. Numerical analysis demonstrates that these one-way modes allow for flexible and effective manipulation of waves in the photonic crystal system with minimal power loss.
OPTICAL MATERIALS EXPRESS
(2021)
Article
Optics
Suna Zhuang, Jianfeng Chen, Wenyao Liang, Zhi-Yuan Li
Summary: The coupling effect of topological photonic states in a double-channel magneto-optical photonic crystal waveguide was studied, revealing both fast and slow light modes with strong robustness against perfect electric conductor defects and close to 100% one-way transmittance.
Article
Robotics
Mingxing Cheng, Qingwei Li
Summary: This study focuses on the formation mechanism of helical actuators, discovering that the anisotropic expansion and Young's modulus of the active layer are crucial for helical curling. These key factors may interact or compete with each other, with the dominant factor determining the chirality.
Article
Chemistry, Multidisciplinary
Sayed Elshahat, Israa Abood, Mohamed Saleh M. Esmail, Zhengbiao Ouyang, Cuicui Lu
Summary: The study introduces a novel photonic crystal mirror heterostructure with high-quality factor (Q) and strong sensing ability and performance. It shows a defect mode at the interface with high Q-factor and enhancement of light-matter interaction, suitable for optical sensing, filtering, and switching applications. The introduction of an electro-optical polymer layer at the interface can further tune the defect mode for higher spatial pulse compression and electro-optical sensitivity.
Article
Chemistry, Multidisciplinary
Giovanni Pierri, Rosaria Schettini, Francesco F. Summa, Francesco De Riccardis, Guglielmo Monaco, Irene Izzo, Consiglia Tedesco
Summary: Enantiomorphic right- and left-handed polyproline type I helices have been observed for the first time in four cyclic dodecapeptoids with methoxyethyl and propargyl side chains using single crystal X-ray diffraction. The absence of NH hydrogen bonds in peptoids reveals the role of intramolecular backbone-to-backbone interactions and CH hydrogen bonds in stabilizing the macrocycle conformation. Additionally, intramolecular backbone-side chain C5 CH hydrogen bonds emerge as a stabilizing factor.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Xinyue Yu, Suna Zhuang, Jianfeng Chen, Zhi-Yuan Li, Wenyao Liang
Summary: The transmission properties of odd/even one-way modes and their reversible conversion in a double-channel waveguide were studied. It was found that the M4 mode supports dispersionless slow-light propagation and the other three modes have strong robustness against defects.
Article
Biochemistry & Molecular Biology
Poulomi Das, Khac Huy Ngo, Fernaldo Richtia Winnerdy, Arijit Maity, Blaz Bakalar, Yves Mechulam, Emmanuelle Schmitt, Anh Tuan Phan
Summary: This study investigates the adaptability of left-handed G4 structures towards the presence of bulges, presenting the structural characteristics of left-handed G4s accommodating varying numbers of bulges. Bulges in left-handed G4s exhibit distinct features compared to those in right-handed G4s, and elucidation of the intricate structural details may enhance understanding of the potential roles and limitations of these unique structures.
NUCLEIC ACIDS RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
Sofyan A. Taya, Malek G. Daher, Abdulkarem H. M. Almawgani, Ayman Taher Hindi, Ilhami Colak, Shobhit K. Patel, Amrindra Pal
Summary: The absorption properties of a photonic crystal (PhC) consisting of high- and low-index dielectric materials and a metamaterial defect layer are investigated in this study. The effects of metamaterial negative permittivity and permeability on the tunable absorption properties of the PhC are analyzed theoretically and numerically in the gigahertz region. The findings show that the number of absorbance peaks increases with the number of unit cells, the absorbance peaks dramatically decay with increasing graphene chemical potential (GCP), and the absorbance peaks exhibit a significant enhancement with increasing graphene phenomenological scattering rate (GPSR).
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Minghui Lu, Soham Dutta, Brian Johnson
Summary: In this article, a decentralized communication-free control strategy is introduced for synchronizing and controlling inverters in an islanded load system. The proposed approach reduces wiring complexity and improves system performance.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Physics, Multidisciplinary
Chu-Hao Xia, Hua-Shan Lai, Xiao-Chen Sun, Cheng He, Yan-Feng Chen
Summary: In this study, higher-order hinge states in an acoustic topological Dirac semimetal were experimentally investigated, revealing the existence of robust nontrivial hinge arcs in addition to removable trivial surface states. The work also showed that a pair of hinges possess arcs located in complementary momentum regions.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Ji-Qian Wang, Zi-Dong Zhang, Si-Yuan Yu, Hao Ge, Kang-Fu Liu, Tao Wu, Xiao-Chen Sun, Le Liu, Hua-Yang Chen, Cheng He, Ming-Hui Lu, Yan-Feng Chen
Summary: The authors provide experimental evidence for extended topological valley-locked states and propose their application in acoustics devices. By combining Dirac semimetals and topological insulators, they demonstrate reduced backscattering and improved matching of surface acoustic waves (SAWs) with interdigital transducers. Through the design and manufacturing of miniaturized phononic crystals on a semi-infinite substrate, they successfully realize valley-locked edge transport for SAWs. This work has important implications for future acoustic information processing, sensing, and manipulation.
NATURE COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Minghui Lu
Summary: In this article, the authors systematically model and study a grid-forming inverter controller, exploring its synchronization dynamics and stability. The controller is able to autonomously regulate system voltages and frequency while exhibiting nonlinear droop-like behavior. Small-signal models are used to analyze the stability and synchronization of both individual inverters and interconnected systems. Numerical simulations and experimental results validate the analytical developments.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Minghui Lu, Sairaj Dhople, Brian Johnson
Summary: This article discusses the time-domain strategy of virtual oscillator control (VOC) and the use of nonlinear oscillator circuits for synchronizing and regulating grid-forming inverters. It focuses on a class of second-order circuits composed of harmonic oscillators and nonlinear damping, and presents analytical methods for deriving performance metrics related to their harmonic and dynamic properties.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Physics, Multidisciplinary
Fei Liang, Cheng He, Dazhi Lu, Qiannan Fang, Yu Fu, Haohai Yu, Huaijin Zhang, Yan-Feng Chen
Summary: In this study, lasers far beyond the fluorescence spectrum were realized in Yb-doped YCa4O(BO3)(3) crystals. Selective amplification of three- to eight-phonon processes and suppression of fewer-phonon ones resulted in an overall spectral tunability of 1,110-1,465 nm. The enhancement of the weak electron-phonon-photon interaction holds significance and opens up new possibilities for on-demand lasers operating outside the fluorescence spectrum.
Article
Energy & Fuels
Olaoluwapo Ajala, Minghui Lu, Brian Johnson, Sairaj Dhople, Alejandro Dominguez-Garcia
Summary: This paper presents reduced-order models for grid-forming virtual-oscillator-controlled inverters with nested control loops and over-current protection. The models take into account the impact of current-reference limiting and are tailored for networks with resistive and inductive interconnecting lines. Computational benefits and accuracy of the models are validated through numerical simulations.
IEEE TRANSACTIONS ON ENERGY CONVERSION
(2022)
Article
Engineering, Electrical & Electronic
Minghui Lu, Sairaj Dhople, Donny Zimmanck, Brian Johnson
Summary: This article investigates the feasibility of using interconnected single-phase droop-controlled grid-forming inverters to build balanced three-phase systems. Through modeling, analysis, and experimentation, it is shown that these inverters are capable of self-organizing into balanced three-phase systems and can operate robustly under voltage and load imbalances.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2022)
Article
Physics, Applied
Bo-Wen Li, Xiao-Chen Sun, Cheng He, Yan-Feng Chen
Summary: This study proposes a method to realize acoustic graphyne by introducing negative coupling to simulate the carbon-carbon triple bond, resulting in the transition from trivial to higher-order topological phases characterized by real Chern numbers. These topologically protected corner states are achieved in a finite-size sample, and the conditions for their existence are discussed. This research extends the concept of real Chern insulators and provides a platform for studying the topological properties of graphene-like structural compounds.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Energy & Fuels
Minghui Lu
Summary: This study focuses on virtual oscillator controlled inverters and proposes an inrush current limiting strategy applicable to inverters in electric power systems where voltages and frequencies are unknown. Experimental results demonstrate that this method can effectively mitigate inverter inrush currents.
IEEE TRANSACTIONS ON ENERGY CONVERSION
(2023)
Article
Materials Science, Multidisciplinary
Yan-Chen Zhou, Hua-Shan Lai, Jian-Lan Xie, Xiao-Chen Sun, Cheng He, Yan-Feng Chen
Summary: Recently, higher-order states have been discovered, enriching the study of topological phases. These states allow for manipulation of wave propagation or localization in dimensions lower than the bulk. In a two-dimensional honeycomb lattice gyromagnetic photonic crystal, magnetic corner states have been realized by breaking time-reversal and parity symmetries. These states arise from the hybridization of two Wannier centers and can be controlled solely by adding or removing magnetic fields at the corner sites.
Proceedings Paper
Green & Sustainable Science & Technology
Soham Dutta, Minghui Lu, Branko Majmunovic, Rahul Mallik, Gab-Su Seo, Dragan Maksimovic, Brian Johnson
Summary: This paper introduces a virtual oscillator controller for bidirectional power transfer in cascaded inverter systems, addressing the limitations of existing decentralized controllers.
2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)
(2021)
Proceedings Paper
Green & Sustainable Science & Technology
Soham Dutta, Minghui Lu, Brian Johnson
Summary: This paper presents a decentralized control technique for minimizing current ripple in parallel connected dc-dc converters, addressing two key issues and proposing a controller that effectively reduces current ripple. The proposed method demonstrates significant reductions in both net current ripple and undesired fundamental harmonic under various operating conditions.
2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)
(2021)
Proceedings Paper
Green & Sustainable Science & Technology
Minghui Lu, Rahul Mallik, Brian Johnson, Sairaj Dhople
Summary: This paper proposes a control framework for photovoltaic inverters integrating DC-side control for peak power harvest and AC-side virtual oscillator controller for grid synchronization. The framework uses multiple control loops to achieve maximum PV power tracking and grid synchronization, and is validated through simulations and experiments.
2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)
(2021)
Proceedings Paper
Engineering, Electrical & Electronic
Ryan Billmeyer, Minghui Lu, Brian Johnson, Sairaj Dhople
Summary: This paper demonstrates the realization of equivalent-circuit representations of grid-following power-electronic inverters within a SPICE-based development environment, which allows computationally lean simulations of inverter networks. The approach is validated through time-domain simulations of a modified IEEE standard 118-bus system in Virtuoso, showing a significant decrease in simulation time with comparable signal resolution compared to a commonly used power-electronics simulation package.
2021 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS)
(2021)
