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Broadband high-efficiency plasmonic metalens with negative dispersion characteristic

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Photonics Research 2024年第4期12卷 813-820页

作者： YONG-QIANG LIU YONG ZHU HONGCHENG YIN JINHAI SUN YAN WANG YONGXING CHE national Key laboratory of Scattering and Radiation Beijing 100854China

Controlling the dispersion characteristic of metasurfaces(or metalenses) along a broad bandwidth is of great importance to develop high-performance broadband metadevices. Different from traditional lenses that rely on the material refractive index along the light trajectory, metasurfaces or metalenses provide a new regime of dispersion control via a sub-wavelength metastructure, which is known as negative chromatic ***, broadband metalenses design with high-performance focusing especially with a reduced device dimension is a significant challenge in society. Here, we design, fabricate, and demonstrate a broadband highperformance diffractive-type plasmonic metalens based on a circular split-ring resonator metasurface with a relative working bandwidth of 28.6%. The metalens thickness is only 0.09λ0(λ0is at the central wavelength),which is much thinner than previous broadband all-dielectric metalenses. The full-wave simulation results show that both high transmissive efficiency above 80%(the maximum is even above 90%) and high average focusing efficiency above 45%(the maximum is 56%) are achieved within the entire working bandwidth of 9–12 ***, an average high numerical aperture of 0.7(NA = 0.7) of high-efficiency microwave metalens is obtained in the simulations. The broadband high-performance metalens is also fabricated and experimental measurements verify its much higher average focusing efficiency of 55%(the maximum is above 65% within the broad bandwidth) and a moderate high NA of 0.6. The proposed plasmonic metalens can facilitate the development of wavelength-dependent broadband diffractive devices and is also meaningful to further studies on arbitrary dispersion control in diffractive optics based on plasmonic metasurfaces.

关键词： resonator dispersion high

Functional genomics of Brassica napus:Progresses,challenges,and perspectives

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Journal of Integrative Plant Biology 2024年第3期66卷 484-509页

作者： Zengdong Tan Xu Han Cheng Dai Shaoping Lu Hanzi He Xuan Yao Peng Chen Chao Yang Lun Zhao Qing-Yong Yang Jun Zou Jing Wen Dengfeng Hong Chao Liu Xianhong Ge Chuchuan Fan Bing Yi Chunyu Zhang Chaozhi Ma Kede Liu Jinxiong Shen Jinxing Tu Guangsheng Yang Tingdong Fu Liang Guo Hu Zhao national Key laboratory of Crop Genetic Improvement Hubei Hongshan LaboratoryHuazhong Agricultural UniversityWuhan 430070China Yazhouwan national laboratory Sanya 572025China

Brassica napus,commonly known as rapeseed or canola,is a major oil crop contributing over 13%to the stable supply of edible vegetable oil *** and understanding the gene functions in the *** genome is crucial for genomic breeding.A group of genes controlling agronomic traits have been successfully cloned through functional genomics studies in *** this review,we present an overview of the progress made in the functional genomics of ***,including the availability of germplasm resources,omics databases and cloned functional *** on the current progress,we also highlight the main challenges and perspectives in this *** advances in the functional genomics of *** contribute to a better understanding of the genetic basis underlying the complex agronomic traits in *** and will expedite the breeding of high quality,high resistance and high yield in *** varieties.

关键词： accelerate breeding Brassica napus functional genomics high resistance high yield

High-frequency microwave cavity design for high-mass dark matter axion searches

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Chinese Physics B 2024年第5期33卷 87-94页

作者：张驰王佳李春光陈石广程航孙亮吴云 Beijing national laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Songshan Lake Materials laboratory Dongguan 523808China Hefei national laboratory Hefei 230088China

The haloscope based on the TM_(010)mode cavity is a well-established technique for detecting QCD ***,the method has limitations in detecting high-mass axion due to significant volume loss in the high-frequency *** a higher-order mode cavity can effectively reduce the volume loss of the high-frequency *** rotatable dielectric pieces as a tuning mechanism can compensate for the degradation of the form factor of the higher-order ***,the introduction of dielectric causes additional volume *** address these issues,this paper proposes a novel design scheme by adding a central metal rod to the higher-order mode cavity tuned by dielectrics,which improves the performance of the haloscope due to the increased effective volume of the cavity *** superiority of the novel design is demonstrated by comparing its simulated performance with previous ***,the feasibility of the scheme is verified by the full-wave simulation results of the mechanical design model.

关键词： axion haloscope microwave cavity

Transient long-range distance measurement by a Vernier spectral interferometry

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Photonics Research 2024年第6期12卷 1107-1114页

作者： LIANG XU KUN WANG CHEN LIU WENYING CHEN CHI ZHANG XINLIANG ZHANG Wuhan national laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Optics Valley laboratory Wuhan 430074China

Rapid and long-range distance measurements are essential in various industrial and scientific applications,and among them,the dual-comb ranging system attracts great attention due to its high ***,the tem-poral asynchronous sampling results in the tradeoff between frame rate and ranging precision,and the non-ambiguity range(NAR)is also limited by the comb cycle,which hinders the further advancement of the dual-comb ranging *** this constraint,we introduce a Vernier spectral interferometry to improve the frame rate and NAR of the ranging ***,leveraging the dispersive time-stretch technology,the dual-comb interferometry becomes spectral ***,the asynchronous time step is unlimited,and the frame rate is improved to 100 ***,dual-wavelength bands are introduced to implement a Vernier spectral interferometry,whose NAR is enlarged from 1.5 m to 1.5 ***,this fast and long-range system also demonstrated high precision,with a 22.91-nm Allan deviation over 10-ms averaging *** a result,the proposed Vernier spectral interferometry ranging system is promising for diverse applications that necessitate rapid and extensive distance measurement.

关键词： interferometry spectral system

Pressure transient characteristics of non-uniform conductivity fractured wells in viscoelasticity polymer flooding based on oil-water two-phase flow

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Petroleum Science 2024年第1期21卷 343-351页

作者： Yang Wang Jia Zhang Shi-Long Yang Ze-Xuan Xu Shi-Qing Cheng national Key laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China

Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil *** contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinning and shear thickening,polymer convection,diffusion,adsorption retention,inaccessible pore volume and reduced effective ***,the flux density and fracture conductivity along the hydraulic fracture are generally non-uniform due to the effects of pressure distribution,formation damage,and proppant *** this paper,we present an oil-water two-phase flow model that captures these complex non-Newtonian and nonlinear behavior,and non-uniform fracture characteristics in fractured polymer *** hydraulic fracture is firstly divided into two parts:high-conductivity fracture near the wellbore and low-conductivity fracture in the far-wellbore section.A hybrid grid system,including perpendicular bisection(PEBI)and Cartesian grid,is applied to discrete the partial differential flow equations,and the local grid refinement method is applied in the near-wellbore region to accurately calculate the pressure distribution and shear rate of polymer *** combination of polymer behavior characterizations and numerical flow simulations are applied,resulting in the calculation for the distribution of water saturation,polymer concentration and reservoir *** with the polymer flooding well with uniform fracture conductivity,this non-uniform fracture conductivity model exhibits the larger pressure difference,and the shorter bilinear flow period due to the decrease of fracture flow ability in the far-wellbore *** field case of the fall-off test demonstrates that the proposed method characterizes fracture characteristics more accurately,and yields fracture half-lengths that better match engineering reality,enabling a quantitative segmented characterization of the near-wellbore section with high fracture conductivity and th

关键词： Polymer flooding Non-Newtonian fluid Non-uniform fracture conductivity Two-phase flow Pressure transient analysis

A redundant subspace weighting procedure for clock ensemble

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Chinese Physics B 2024年第4期33卷 435-442页

作者：徐海陈煜刘默驰王玉琢 national Institute of Metrology Beijing 100029China Key laboratory of State Administration for Market Regulation Beijing 100029China china national Intellectual Property Administration Beijing 100088China

A redundant-subspace-weighting(RSW)-based approach is proposed to enhance the frequency stability on a time scale of a clock *** this method,multiple overlapping subspaces are constructed in the clock ensemble,and the weight of each clock in this ensemble is defined by using the spatial covariance *** superimposition average of covariances in different subspaces reduces the correlations between clocks in the same laboratory to some *** optimizing the parameters of this weighting procedure,the frequency stabilities of virtual clock ensembles are significantly improved in most cases.

关键词： weighting method redundant subspace clock ensemble time scale

Adaptive learning-based optimal tracking control system design and analysis of a disturbed nonlinear hypersonic vehicle model

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Science china(Technological Sciences) 2024年第6期67卷 1893-1906页

作者： AN Kai WANG ZhenGuo HUANG Wei Hypersonic Technology laboratory National University of Defense TechnologyChangsha410073China

We propose an adaptive learning-based optimal control scheme for height-velocity control models considering model uncertainties and external disturbances of hypersonic winged-cone *** longitudinal nonlinear model is first established and transformed into the control-oriented error equations,and the control scheme is organized by a steady-compensation *** overcome and eliminate the impact of model uncertainties and external disturbances,an adaptive radial basis function neural network(RBFNN)is designed by a q-gradient *** the height-velocity error system with estimated uncertainties into account,the adaptive learning-based optimal tracking control(ALOTC)scheme is proposed by combining the critic-only adaptive dynamic programming(ADP)framework and parameter optimization of system settling ***,a novel weight update law is proposed to satisfy the online iteration requirements,and the algorithm convergence and closedloop stability are discussed by the Lyapunov ***,four simulation cases are provided to prove the effectiveness,accuracy,and robustness of the proposed scheme for the hypersonic longitudinal control system.

关键词： optimal tracking control adaptive dynamic programming RBFNN hypersonic vehicle

Analytical solution for the effective elastic properties of rocks with the tilted penny-shaped cracks in the transversely isotropic background

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Petroleum Science 2024年第1期21卷 221-243页

作者： Zheng-Qian Ma Xing-Yao Yin Zhao-Yun Zong Yuan-Yuan Tan Ya-Ming Yang national Key laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Pilot national laboratory for Marine Science and Technology(Qingdao) Qingdao266200ShandongChina

Seismic prediction of cracks is of great significance in many disciplines,for which the rock physics model is ***,up to now,multitudinous analytical models focus primarily on the cracked rock with the isotropic background,while the explicit model for the cracked rock with the anisotropic background is rarely investigated in spite of such case being often encountered in the ***,we first studied dependences of the crack opening displacement tensors on the crack dip angle in the coordinate systems formed by symmetry planes of the crack and the background anisotropy,respectively,by forty groups of numerical *** on the conclusion from the experiments,the analytical solution was derived for the effective elastic properties of the rock with the inclined penny-shaped cracks in the transversely isotropic ***,we comprehensively analyzed,according to the developed model,effects of the crack dip angle,background anisotropy,filling fluid and crack density on the effective elastic properties of the cracked *** analysis results indicate that the dip angle and background anisotropy can significantly either enhance or weaken the anisotropy degrees of the P-and SH-wave velocities,whereas they have relatively small effects on the SV-wave velocity ***,the filling fluid can increase the stiffness coefficients related to the compressional modulus by reducing crack compliance parameters,while its effects on shear coefficients depend on the crack dip *** increasing crack density reduces velocities of the dry rock,and decreasing rates of the velocities are affected by the crack dip *** comparing with exact numerical results and experimental data,it was demonstrated that the proposed model can achieve high-precision estimations of stiffness ***,the assumption of the weakly anisotropic background results in the consistency between the proposed model and Hudson's published theory for the or

关键词： Effective elastic property Tilted crack Transverse isotropy Analytical solution Crack opening displacement

Encoding innumerable charge density waves of FeGe into polymorphs of LiFe6Ge6

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Science china(Physics,Mechanics & Astronomy) 2024年第9期Mechanics & Astronomy) .卷 130-136页

作者： Yilin Wang School of Emerging Technology University of Science and Technology of China Hefei national laboratory University of Science and Technology of China New Cornerstone Science laboratory University of Science and Technology of China

Kagome metals exhibit rich quantum states by the intertwining of lattice,charge,orbital and spin degrees of ***,a novel charge density wave （CDW） ground state was discovered in kagome magnet FeGe and was revealed to be driven by lowering magnetic energy via large ***,based on DFTcalculations,we show that such mechanism will yield infinitely many metastable CDWs in FeGe due to different ways to arrange the Ge1-dimerization in enlarged ***,utilizing these metastable CDWs,innumerable polymorphs of kagome magnet LiFe6Ge6can be stabilized by filling Li atoms in the voids right above/below the dimerized Ge1-sites in the CDW *** polymorphs are very stable due to the presence of magnetic-energy-saving mechanism,in sharp contrast to the non-magnetic “166” kagome *** this way,a one-to-one mapping of the metastable CDWs of FeGe to stable polymorphs of LiFe6Ge6is *** one hand,the fingerprints of these metastable CDWs,i.e.,the induced in-plane atomic distortions and band gaps,are encoded into the corresponding stable polymorphs of LiFe6Ge6,such that further study of their properties becomes *** the other hand,such innumerable polymorphs of LiFe6Ge6offer great degrees of freedom to explore the rich physics of magnetic kagome *** thus reveal a novel connection between the unusually abundant CDWs and structural polymorphism in magnetic kagome materials,and establish a new route to obtain structural polymorphism on top of CDW states.

关键词： kagome magnet unconventional charge density wave structural polymorphism magnetic energy saving