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Adaptive sampling for corrugated plate digitization using a laser displacement sensor

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Science China(Technological Sciences) 2024年第5期67卷 1510-1523页

作者： WU ChengXing QI Qi CHEN BaiJin YANG JiXiang DING Han State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical apparatus.Traditional detection methods are impractical for real-world production,being slow and destructive.In contrast,the point laser displacement sensor,employing the optical triangle method,emerges as a promising device for assessing parts with variable curvature and highly reflective surfaces.Despite its benefits,high-density sampling by an innate frequency introduces challenges such as data redundancy and a poor signal-to-noise ratio,potentially affecting the efficiency and precision of subsequent data processing.To address these challenges,adjustable frequency data sampling has been developed for this sensor,allowing adaptive sampling for corrugated plate digitization.The process begins with surface digitization to extract discrete points,which are transformed into intersection curves using the B-spline fitting technique.Subsequently,dominant points are identified,considering multigeometric constraints for curvature and arch height.Finally,the sampling signal is adjusted based on the distribution information of dominant points.Comparative results indicate that the proposed method effectively minimizes redundant sampling without compromising the accurate capture of essential geometric features.

关键词： corrugated plate laser displacement sensor adaptive sampling dominant point curvature arch height

Layer-Valley Hall Effect under Inversion and Time-Reversal Symmetries

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Chinese Physics Letters 2024年第6期41卷 88-97页

作者：赵交交刘贵斌陈鹏姚裕贵张广宇杜罗军 Beijing National Laboratory for Condensed Matter Physics and Key Laboratory for Nanoscale Physics and DevicesInstitute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE)School of PhysicsBeijing Institute of TechnologyBeijing 100081China Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of TechnologyBeijing 100081China Schoolof Microelectronics Southern University of Science and TechnologyShenzhen 518055China Songshan Lake Materials Laboratory Dongguan 523808China

Hall effects have been the central paradigms in modern physics,materials science and practical applications,and have led to many exciting breakthroughs,including the discovery of topological Chern invariants and the revolution of metrological resistance standard.To date,the Hall effects have mainly focused on a single degree of freedom(Do F),and most of them require the breaking of spatial-inversion and/or time-reversal symmetries.Here we demonstrate a new type of Hall effect,i.e.,layer-valley Hall effect,based on a combined layer-valley Do F characterized by the product of layer and valley indices.The layer-valley Hall effect has a quantum origin arising from the layer-valley contrasting Berry curvature,and can occur in nonmagnetic centrosymmetric crystals with both spatial-inversion and time-reversal symmetries,transcending the symmetry constraints of single Do F Hall effect based on the constituent layer or valley index.Moreover,the layer-valley Hall effect is highly tunable and shows a W-shaped pattern in response to the out-of-plane electric fields.Additionally,we discuss the potential detection approaches and material-specific design principles of layer-valley Hall effect.Our results demonstrate novel Hall physics and open up exotic paradigms for new research direction of layer-valleytronics that exploits the quantum nature of the coupled layer-valley DoF.

关键词： quantum Inversion curvature

A Dual Yamabe Flow and Related Integral Flows

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 319-348页

作者： Jingang XIONG School of Mathematical Sciences Laboratory of Mathematics and Complex Systems Ministry of Edu-cation Beijing Normal University

The author studies a family of nonlinear integral flows that involve Riesz potentials on Riemannian manifolds. In the Hardy-Littlewood-Sobolev (HLS for short)subcritical regime, he presents a precise blow-up profile exhibited by the flows. In the HLS critical regime, by introducing a dual Q curvature he demonstrates the concentrationcompactness phenomenon. If, in addition, the integral kernel matches with the Green’s function of a conformally invariant elliptic operator, this critical flow can be considered as a dual Yamabe flow. Convergence is then established on the unit spheres, which is also valid on certain locally conformally flat manifolds.

关键词： Hardy-Littlewood-Sobolev functional Dual Q curvature Integral flow 45K05 35B33

curvature flow learning: algorithm and analysis

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Science China(Information Sciences) 2022年第9期65卷 113-126页

作者： Yangyang LI Ruqian LU Key Lab of MADIS Academy of Mathematics and Systems Science Chinese Academy of Sciences

In order to describe the nonlinear distribution of the image dataset, researchers propose a manifold assumption, called manifold learning(MAL). The geometry information based on a manifold is measured by the Riemannian metric, such as the geodesic distance. Thus, owing to mining the intrinsic geometric structure of the dataset, we need to learn the real Riemannian metric of the embedded manifold. By the Taylor expansion equation of the Riemannian metric, it clearly indicates that the Riemannian metric is relative to the Riemannian curvature. Based on it, we propose a new algorithm to learn the Riemannian metric by adding the curvature information into metric learning. By optimizing the objective function, we obtain a set of iterative equations. We call this model curvature flow. By employing this curvature flow, we obtain a Mahalanobis metric that approaches the Riemannian metric infinitely and can well uncover the intrinsic structure of the embedded manifold. In theory, we analyze several properties of our proposed method, e.g.,the boundedness of the metric and the convergence of curvature flow. To show the effectiveness of our proposed method, we compare our algorithm with several traditional MAL algorithms on three real world datasets. The corresponding results indicate that our proposed method outperforms the other algorithms.

关键词： metric learning Riemannian metric curvature flow learning manifold learning

curvature-controlled band alignment transition in 1D van der Waals heterostructures

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npj Computational Materials 2023年第1期9卷 1411-1419页

作者： Shu Zhao Chunxia Yang Ziye Zhu Xiaoping Yao Wenbin Li School of Materials Science and Engineering Zhejiang University310027 HangzhouChina Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province School of EngineeringWestlake University310030 HangzhouChina Institute of Advanced Technology Westlake Institute for Advanced Study310024 HangzhouChina

The effect of curvature on the band alignment of one-dimensional (1D) van der Waals (vdW) transition metal dichalcogenide(TMDC) heterostructures is studied by comprehensive first-principles calculations. We find that, as the diameter of a TMDCnanotube decreases, the combined effect of curvature-induced flexoelectricity and circumferential tensile strain causes a rapidlowering of the conduction band minimum, whereas the valence band maximum exhibits an initial lowering before rising. Asindividual TMDC nanotubes form coaxial heterostructures, the concerted effect of diameter-dependent band-edge levels andintertube coupling via flexovoltage can result in a transition of intertube band alignment from Type II to Type I in multipleheterostructural systems, including large-diameter MoSe_(2)@WS_(2), MoTe_(2)@MoSe_(2), and MoTe_(2)@WS_(2) heterostructures. These results laydown a foundation for the rational design of 1D vdW heterostructures.

关键词： alignment curvature band

Over-correction of curvature causes the non-surgical curvature loss in one- and two-level anterior cervical discectomy and fusion

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Chinese Medical Journal 2022年第13期135卷 1634-1636页

作者： Yingjun Guo Hao Liu Yang Meng Chen Ding Ying Hong Beiyu Wang Department of Orthopaedics West China HospitalSichuan UniversityChengduChina.

To the Editor:Cervical disc degenerative disease(CDDD)is a common clinical spinal disease,which has a great impact on the quality of life of middle-aged and elderly patients.[1,2]Although it is challenged by advanced surgical techniques,anterior cervical discectomy and fusion(ACDF)is still the best choice for most patients with CDDD.[3,4]In most cases,the focus of ACDF surgery is“decompression.”However,for patients with preoperatively poor curvature,in addition to the decompression of the nerve to relieve symptoms,it is also vital to improve the cervical curvature.

关键词： cervical surgical curvature

Small bending, big curvature^(FA)

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Journal of Integrative Plant Biology 2022年第1期64卷 3-4页

作者： Wenkun Zhou Xiaoyue Zhang State Key Laboratory of Plant Physiology and Biochemistry College of Biological SciencesChina Agricultural UniversityBeijing 100193China State Key Laboratory of Plant Genomics National Center for Plant Gene Research(Beijing)Institute of Genetics and Developmental BiologyInnovation Academy of Seed Designthe Chinese Academy of SciencesBeijing 100101China

The classical"Cholodny-Went theory"predicted that directional stimuli trigger the redistribution of auxin,which governs the differential growth of plant organs through potent effects on cell expansion,thereby establishing an"auxin-then-growth"paradigm;this theory has been validated for both gravitropism and phototropism in plants(reviewed in Muthert et al.,2020).

关键词： curvature thereby establishing

curvature Sensor Based on a Long-Period Grating in a Fiber Ring Resonator Interrogated by an OTDR

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Photonic Sensors 2020年第1期10卷 1-6页

作者： Regina MAGALHAES Susana SILVA Orlando FRAZAO INESC TEC and Department of Physics and Astronomy Faculty of Sciences of University of PortoPorto 4169-007Portugal

The proposed technique demonstrates a fiber ring resonator interrogated by an optical time domain reflectometer(OTDR),for intensity sensing.By using this methodology,a cavity round trip time of 2.85ms was obtained.For a proof of concept,a long-period grating was inserted in the resonant cavity operating as a curvature sensing device.A novel signal processing approach was outlined,regarding to the logarithmic behavior of the OTDR.Through analyzing the experimental results,an increase in the measured sensitivities was obtained by increasing applied bending.With curvatures performed from 1.8 m^(-1) to 4.5 m^(-1),the sensitivity values ranged from 2.94 dB·km^(-1) to 5.15 dB·km^(-1).In its turn,the sensitivities obtained presented a linear behavior when studied as a function of the applied curvature,following a slope of 0.86×10-3 dB.The advantages of applying this technique were also discussed,demonstrating two similar fiber rings multiplexed in a series of configurations.

关键词： Cavity ring-down curvature fiber ring resonator long period grating optical fiber sensors OTDR

curvature-induced lipid segregation

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Chinese Physics B 2015年第6期24卷 95-99页

作者：郑斌孟庆田 Robin L.B.Selinger Jonathan V.Selinger 叶方富 College of Physics and Electronics Shandong Normal University Beijing National Laboratory for Condensed Matter Physics and Key Laboratory of Soft Matter Physics of Chinese Academy of Sciences Institute of PhysicsChinese Academy of Sciences Liquid Crystal Institute Kent State University

We investigate how an externally imposed curvature influences lipid segregation on two-phase-coexistent membranes. We show that the bending-modulus contrast of the two phases and the curvature act together to yield a reduced effective line tension. On largely curved membranes, a state of multiple domains （or rafts） forms due to a mechanism analogous to that causing magnetic-vortex formation in type-II superconductors. We determine the criterion for such a multi-domain state to occur; we then calculate respectively the size of the domains formed on cylindrically and spherically curved membranes.

关键词： curvature phase separation lipid membrane rafts