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Direct observation of spreading precursor liquids in a corner

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National Science Review 2023年第7期10卷 196-202页

作者： Weining Miao Shihao Tian Quanzi Yuan Ye Tian Lei Jiang Key Laboratory of Bioinspired Smart Interfacial Science Technical Institute of Physics and Chemistry Chinese Academy of Sciences School of Future Technology University of Chinese Academy of Sciences State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences

Precursor liquid is a nanoscale liquid creeping ahead of the macroscopic edge of spreading liquids,whose behaviors tightly correlate with the three-phase reaction efficiency and patterning accuracy.However,the important spatial-temporal characteristic of the precursor liquid still remains obscure because its real-time spreading process has not been directly observed.Here,we report that the spreading ionic liquid precursors in a silicon corner can be directly captured on video using in situ scanning electron microscopy.In situ spreading videos show that the precursor liquid spreads linearly over time(ΔL～ΔT) rather than obeying the classic Lucas-Washburn law(l～t1/2) and possesses a characteristic width of ～250-310 nm.Theoretical analyses and molecular dynamics simulations demonstrate that the unique behaviors of precursor liquids originate from the competing effect of van der Waals force and surface energy.These findings provide avenues for directly observing liquid/solid interfacial phenomena on a microscopic level.

关键词： precursor liquid spreading spatial–temporal characteristic direct observation corner ionic liquids

Topological multipolar corner state in a supercell metasurface and its interplay with two-dimensional materials

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Photonics Research 2022年第4期10卷 855-869页

作者： Zhaojian Zhang Junbo Yang Te Du Xinpeng Jiang College of Liberal Arts and Sciences National University of Defense TechnologyChangsha 410073China Center of Material Science National University of Defense TechnologyChangsha 410073China

Second-order topological insulators(SOTIs) have recently attracted much attention due to their capability to support lower-dimensional topological states, namely, the corner states. Here, we demonstrate that properly designed supercell metasurfaces can support photonic corner states, meanwhile further serving as an ideal platform for the implementations of topological polaritons and dynamically reconfigurable corner states by assembling two-dimensional materials. Such metasurfaces consist of an array of finite-sized SOTIs mimicking the twodimensional Su–Schrieffer–Heeger model. We reveal that the topological transition happens in unit cells without the bandgap, and nondegenerate multipolar corner states emerge in the supercell metasurface due to the inter-and intrasupercell coupling effects. Especially since these corner states are above the light line of the metasurface, we realize the collective stimulation of the two dipolar corner states and their superposition state via far-field excitation. By stacking monolayer hexagonal boron nitride film onto the metasurface, we further achieve the topological phonon polaritons through the strong coupling between the corner state and the phonon, which is confirmed by the Rabi splitting as well as anticrossing behavior emerging in the transmission spectra.Furthermore, we reveal the robustness of the corner state and strong coupling by introducing defects into the metasurface. Finally, tunable corner state and strong coupling with on-demand control are realized by assembling monolayer graphene onto the metasurface. Our theoretical study proposes a unique hybrid-material platform for topological polaritonics and reconfigurable topological photonics, which can promote large-area topological applications in practice.

关键词： polar while corner

Experimental observation of multiple edge and corner states in photonic slabs heterostructures

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Photonics Research 2022年第1期10卷 197-204页

作者： MINGXING LI YUEKE WANG TIAN SANG HONGCHEN CHU YUN LAI GUOFENG YANG Optical Information Science and Technology Department Jiangnan UniversityWuxi 214122China Optoelectronic Engineering and Technology Research Center Jiangnan UniversityWuxi 214122China National Laboratory of Solid State Microstructures School of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

The photonic topological insulator has become an important research topic with a wide range of applications.Especially the higher-order topological insulator,which possesses gapped edge states and corner or hinge states in the gap,provides a new scheme for the control of light in a hierarchy of dimensions.In this paper,we propose a heterostructure composed of ordinary-topological-ordinary(OTO)photonic crystal slabs.Two coupled edge states(CESs)are generated due to the coupling between the topological edge states of the ordinary-topological interfaces,which opens up an effective way for high-capacity photonic transport.In addition,we obtain a new band gap between the CESs,and the two kinds of coupled corner states(CCSs)appear in the OTO bend structure.In addition,the topological corner state is also found,which arises from the filling anomaly of a lattice.Compared with the previous topological photonic crystal based on C-4 lattice,CESs,CCSs,and the topological corner state are all directly observed in experiment by using the near-field scanning technique,which makes the manipulation of the electromagnetic wave more flexible.We also verify that the three corner states are all robust to defects.Our work opens up a new way for guiding and trapping the light flow and provides a useful case for the coupling of topological photonic states.

关键词： ordinary has corner

An air cavity method for increasing the underwater acoustic targets strength of corner reflector

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Defence Technology（防务技术） 2020年第2期16卷 493-501页

作者： Yi Luo Xin Chen Da-wei Xiao Wu-di Wen Tao-tao Xie Dept.of Weaponry Eng Naval University of EngineeringWuhan 430033China

In order to improve the underwater acoustic target strength of comer reflectors,according to the principle of acoustic impedance mismatch of the boundary layer,the method of using air cavity to increase the underwater acoustic target strength of corner reflectors is proposed.The acoustic reflection coefficients of underwater air layer and single layer metal sheet are calculated and compared.The results show that the reflection coefficient of single layer metal sheet is greatly affected by frequency and incidence angle,and the reflection coefficient of air layer in water is large and little affected by frequency and incidence angle.On this basis,a new kind of airfilled cavity corner reflector is designed.The acoustic scattering characteristics of underwater airfilled cavity comer reflector are calculated cumulatively,and the results are compared with the monolayer metal sheet corner reflector.The simulation results show that the acoustic reflection effect of the airfilled cavity corner reflector is better.In order to verify the correctness of the method,the test was carried out in the silencing tank.The experimental results show that the simulation results are in good agreement with the experimental results,and the airfilled cavity can improve on acoustic reflection performance of the underwater corner reflector.

关键词： Underwater corner reflector Acoustic target strength Air cavity Acoustic impedance mismatch

In-Plane Magnetization-Induced corner States in Bismuthene

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Chinese Physics Letters 2022年第1期39卷 27-30页

作者：韩彬曾俊杰乔振华 ICQD Hefei National Laboratory for Physical Sciences at MicroscaleUniversity of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Strongly Coupled Quantum Matter Physics and Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China

We theoretically demonstrate that the electronic second-order topological insulator with robust corner states,having a buckled honeycomb lattice, can be realized in bismuthene by inducing in-plane magnetization. Based on the sp^(3) Slater–Koster tight-binding model with parameters extracted from first-principles results, we show that spin-helical edge states along zigzag boundaries are gapped out by the in-plane magnetization whereas four robust in-gap electronic corner states at the intersection between two zigzag boundaries arise. By regulating the orientation of in-plane magnetization, we show different position distribution of four corner states with different energies. Nevertheless, it respects some spatial symmetries and thus can protect the higher-order topological phase. Combined with the Kane–Mele model, we discuss the influence of the magnetization orientation on the position distribution of corner states.

关键词： magnetization zigzag corner

Control mechanism and technique of floor heave with reinforcing solid coal side and floor corner in gob-side coal entry retaining

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International Journal of Mining Science and Technology 2012年第6期22卷 832-836页

作者： Chen Yong Bai Jianbiao Yan Shuai Xu Ying Wang Xiangyu Ma Shuqi State Key Laboratory of Coal Resources and Mine Safety School of MinesChina University of Mining & Technology Faculty of Engineering University of Wollongong

Floor heave is the most common convergence in gob-side entry retaining.The paper analyzes the form,process and characteristics of gob-side entry retaining with the comprehensive methods of theoretical analysis,numerical simulation and the field trial.Research results present that bending and folding floor heave is the main factor in the stage of the first panel mining;squeezing and fluidity floor heave plays a great role in the stable stage of gob-side entry retaining;the combination of the former two factors affects mainly the stage of the second mining ahead;abutment pressure is a fundamental contribution to the serious floor heave of gob-side entry retaining,and sides corners of solid coal body are key part in the case of floor heave controlling of gob-side entry retaining.Floor heave of gob-side entry retaining can be significantly controlled by reinforcing sides and corners of solid coal body,and influence rules on the floor heave of gob side entry retaining of sides supporting strength and the bottom bolt orientation in solid coal side are obtained.Research results have been successfully applied in gob-side entry retaining of G20-F23070 face haulage roadway in #2 coal mine of Pingmei Group,and the field observation shows that the proposed technique is an effective way in controlling the floor heave of gob-side entry retaining.

关键词： Gob-side entry retaining Abutment pressure Forms of floor heave Reinforcing sides of solid coal side Bolt in a floor corner

TEST METHOD FOR SINGLE INTERIOR RIGHT ANGLE IN A corner CUBE PRISM

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Geo-Spatial Information Science 2000年第3期3卷 73-75页

作者： Weng Xingtao He Ping'an Li Song Wang Jiyao School of Photoelectric Engineering WTUSM Wuhan China

A new test method for single interior right angle in a corner cube prism is presented. Some key points and parameters are analyzed and derived. The advantage of this method is concluded by comparing with some current ... 详细信息

关键词： corner cube prism right angle measurement autocollimation

corner-Based Image Alignment using Pyramid Structure with Gradient Vector Similarity

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Journal of Signal and Information Processing 2013年第3期4卷 114-119页

作者： Chin-Sheng Chen Kang-Yi Peng Chien-Liang Huang Chun-Wei Yeh Department of Electronic Electrical & Computer Engineering University of Birmingham UK. Graduate Institute of Automation Technology National Taipei University of Technology

This paper presents a corner-based image alignment algorithm based on the procedures of corner-based template matching and geometric parameter estimation. This algorithm consists of two stages: 1) training phase, and 2) matching phase. In the training phase, a corner detection algorithm is used to extract the corners. These corners are then used to build the pyramid images. In the matching phase, the corners are obtained using the same corner detection algorithm. The similarity measure is then determined by the differences of gradient vector between the corners obtained in the template image and the inspection image, respectively. A parabolic function is further applied to evaluate the geometric relationship between the template and the inspection images. Results show that the corner-based template matching outperforms the original edge-based template matching in efficiency, and both of them are robust against non-liner light changes. The accuracy and precision of the corner-based image alignment are competitive to that of edge-based image alignment under the same environment. In practice, the proposed algorithm demonstrates its precision, efficiency and robustness in image alignment for real world applications.

关键词： corner-Based Image Alignment corner Detection Edge-Based Template Matching Gradient Vector

Hydrodynamic Mixed Convection in a Lid-Driven Hexagonal Cavity with corner Heater

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American Journal of Computational Mathematics 2018年第3期8卷 245-258页

作者： M. Jahirul Haque Munshi Golam Mostafa A. B. S. Manik Munsi Md. Waliullah Department of Mathematics Hamdard University Bangladesh Munshiganj Bangladesh Department of Mathematics Jagannath University Dhaka Bangladesh

Hydrodynamic mixed convection in a lid-driven hexagonal cavity with corner heater is numerically simulated in this paper by employing finite element method. The working fluid is assigned as air with a Prandtl num-ber of 0.71 throughout the simulation. The left and right walls of the hex-agonal cavity are kept thermally insulated and the lid moves top to bottom at a constant speed U0. The top left and right walls of the enclosure are maintained at cold temperature Tc. The bottom right wall is considered with a corner heater whereas the bottom remaining part is adiabatic and inside the cavity a square shape heated block Th. The focus of the work is to investigate the effect of Hartmann number, Richardson number, Grashof number and Reynolds number on the fluid flow and heat transfer characteristics inside the enclosure. A set of graphical results is presented in terms of streamlines, isotherms, local Nusselt number, velocity profiles, temperature profiles and average Nusselt numbers. The results reveal that heat transfer rate increases with increasing Richardson number and Hartmann number. It is also observed that, Hartmann number is a good control parameter for heat transfer in fluid flow in hexagonal cavity.

关键词： Mixed Convection Lid-Driven Hexagonal Cavity Finite Element Method Square Block corner Heater