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Modeling Near-Field Impulsive Waves Generated by Deformable Landslide Using the HBP Model Based on the SPH Method
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作者 WANG Wei WEI Weicheng +4 位作者 CHAI Bo XIA Hao WANG Yang DU Juan LIU Jizhixian 《Journal of Ocean University of China》 CAS CSCD 2024年第2期328-344,共17页
Landslide-generated impulsive waves(LGWs)in reservoir areas can seriously threaten waterway safety as well as hu-man life and properties around the two side slopes.The risk reduction and mitigation of such a hazard re... Landslide-generated impulsive waves(LGWs)in reservoir areas can seriously threaten waterway safety as well as hu-man life and properties around the two side slopes.The risk reduction and mitigation of such a hazard require the accurate prediction of near-field wave characteristics,such as wave amplitude and run-up.However,near-field LGW involves complicated fluid-solid interactions.Furthermore,the wave characteristics are closely related to various aspects,including the geometry and physical features of the slide,river,and body of water.However,the empirical or analytical methods used for rough estimation cannot derive accurate results,especially for deformable landslides,due to their significant geometry changes during the sliding process.In this study,the near-field waves generated by deformable landslides were simulated by smoothed particle hydrodynamics(SPH)based on multi-phase flow.The deformable landslides were generalized as a kind of viscous flow by adopting the Herschel-Bulkley-Papanastasiou(HBP)-based nonNewtonian rheology model.The HBP model is capable of producing deformable landslide dynamics even though the high-speed sliding process is involved.In this study,an idealized experiment case originating from Lituya LGW and a practical case of Gongjiafang LGW were reproduced for verification and demonstration.The simulation results of both cases show satisfactory consistency with the experiment/investigation data in terms of landslide movement and near-field impulsive wave characteristics,thus indicating the applicability and accuracy of the proposed method.Finally,the effects of the HBP model’s rheological parameters on the landslide dynamics and near-field wave characteristics are discussed,providing a parameter calibration method along with sug-gestions for further applications. 展开更多
关键词 deformable landslide impulsive waves near-field SPH nonNewtonian fluids
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A historical overview of nano-optics:From near-field optics to plasmonics
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作者 邓妙怡 朱星 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期134-145,共12页
Nano-optics is an emergent research field in physics that appeared in the 1980s,which deals with light–matter optical interactions at the nanometer scale.In early studies of nano-optics,the main concern focus is to o... Nano-optics is an emergent research field in physics that appeared in the 1980s,which deals with light–matter optical interactions at the nanometer scale.In early studies of nano-optics,the main concern focus is to obtain higher optical resolution over the diffraction limit.The researches of near-field imaging and spectroscopy based on scanning near-field optical microscopy(SNOM)are developed.The exploration of improving SNOM probe for near-field detection leads to the emergence of surface plasmons.In the sense of resolution and wider application,there has been a significant transition from seeking higher resolution microscopy to plasmonic near-field modulations in the nano-optics community during the nano-optic development.Nowadays,studies of nano-optics prefer the investigation of plasmonics in different material systems.In this article,the history of the development of near-field optics is briefly reviewed.The difficulties of conventional SNOM to achieve higher resolution are discussed.As an alternative solution,surface plasmons have shown the advantages of higher resolution,wider application,and flexible nano-optical modulation for new devices.The typical studies in different periods are introduced and characteristics of nano-optics in each stage are analyzed.In this way,the evolution progress from near-field optics to plasmonics of nano-optics research is presented.The future development of nano-optics is discussed then. 展开更多
关键词 NANO-OPTICS near-field optics surface plasmon plasmonic modulation
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Influence of substrate effect on near-field radiative modulator based on biaxial hyperbolic materials
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作者 刘睿一 刘皓佗 +2 位作者 胡杨 崔峥 吴小虎 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期56-64,共9页
Relative rotation between the emitter and receiver could effectively modulate the near-field radiative heat transfer(NFRHT)in anisotropic media.Due to the strong in-plane anisotropy,natural hyperbolic materials can be... Relative rotation between the emitter and receiver could effectively modulate the near-field radiative heat transfer(NFRHT)in anisotropic media.Due to the strong in-plane anisotropy,natural hyperbolic materials can be used to construct near-field radiative modulators with excellent modulation effects.However,in practical applications,natural hyperbolic materials need to be deposited on the substrate,and the influence of substrate on modulation effect has not been studied yet.In this work,we investigate the influence of substrate effect on near-field radiative modulator based onα-MoO_(3).The results show that compared to the situation without a substrate,the presence of both lossless and lossy substrate will reduce the modulation contrast(MC)for different film thicknesses.When the real or imaginary component of the substrate permittivity increases,the mismatch of hyperbolic phonon polaritons(HPPs)weakens,resulting in a reduction in MC.By reducing the real and imaginary components of substrate permittivity,the MC can be significantly improved,reaching 4.64 forε_(s)=3 at t=10 nm.This work indicates that choosing a substrate with a smaller permittivity helps to achieve a better modulation effect,and provides guidance for the application of natural hyperbolic materials in the near-field radiative modulator. 展开更多
关键词 near-field radiative modulator substrate effect hyperbolic material modulation contrast
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Near-field radiative heat transfer between nanoporous GaN films
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作者 韩晓政 张纪红 +2 位作者 刘皓佗 吴小虎 冷惠文 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期109-120,共12页
Photon tunneling effects give rise to surface waves,amplifying radiative heat transfer in the near-field regime.Recent research has highlighted that the introduction of nanopores into materials creates additional path... Photon tunneling effects give rise to surface waves,amplifying radiative heat transfer in the near-field regime.Recent research has highlighted that the introduction of nanopores into materials creates additional pathways for heat transfer,leading to a substantial enhancement of near-field radiative heat transfer(NFRHT).Being a direct bandgap semiconductor,GaN has high thermal conductivity and stable resistance at high temperatures,and holds significant potential for applications in optoelectronic devices.Indeed,study of NFRHT between nanoporous GaN films is currently lacking,hence the physical mechanism for adding nanopores to GaN films remains to be discussed in the field of NFRHT.In this work,we delve into the NFRHT of GaN nanoporous films in terms of gap distance,GaN film thickness and the vacuum filling ratio.The results demonstrate a 27.2%increase in heat flux for a 10 nm gap when the nanoporous filling ratio is 0.5.Moreover,the spectral heat flux exhibits redshift with increase in the vacuum filling ratio.To be more precise,the peak of spectral heat flux moves fromω=1.31×10^(14)rad·s^(-1)toω=1.23×10^(14)rad·s^(-1)when the vacuum filling ratio changes from f=0.1 to f=0.5;this can be attributed to the excitation of surface phonon polaritons.The introduction of graphene into these configurations can highly enhance the NFRHT,and the spectral heat flux exhibits a blueshift with increase in the vacuum filling ratio,which can be explained by the excitation of surface plasmon polaritons.These findings offer theoretical insights that can guide the extensive utilization of porous structures in thermal control,management and thermal modulation. 展开更多
关键词 near-field radiative heat transfer nanoporous GaN film surface phonon polaritons surface plasmon polaritons
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Localization for mixed near-field and far-field sources under impulsive noise
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作者 GAO Hongyuan ZHANG Yuze +2 位作者 DU Ya’nan CHENG Jianhua CHEN Menghan 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期302-315,共14页
In order to solve the problem that the performance of traditional localization methods for mixed near-field sources(NFSs)and far-field sources(FFSs)degrades under impulsive noise,a robust and novel localization method... In order to solve the problem that the performance of traditional localization methods for mixed near-field sources(NFSs)and far-field sources(FFSs)degrades under impulsive noise,a robust and novel localization method is proposed.After eliminating the impacts of impulsive noise by the weighted out-lier filter,the direction of arrivals(DOAs)of FFSs can be estimated by multiple signal classification(MUSIC)spectral peaks search.Based on the DOAs information of FFSs,the separation of mixed sources can be performed.Finally,the estimation of localizing parameters of NFSs can avoid two-dimension spectral peaks search by decomposing steering vectors.The Cramer-Rao bounds(CRB)for the unbiased estimations of DOA and range under impulsive noise have been drawn.Simulation experiments verify that the proposed method has advantages in probability of successful estimation(PSE)and root mean square error(RMSE)compared with existing localization methods.It can be concluded that the proposed method is effective and reliable in the environment with low generalized signal to noise ratio(GSNR),few snapshots,and strong impulse. 展开更多
关键词 source localization far-field source(NFS) near-field source(FFS) impulsive noise Cramer-Rao bound(CRB)
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Towards Near-Field Communications for 6G:Challenges and Opportunities
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作者 LIU Mengyu ZHANG Yang +2 位作者 JIN Yasheng ZHI Kangda PAN Cunhua 《ZTE Communications》 2024年第1期3-15,共13页
Extremely large-scale multiple-input multiple-output(XL-MIMO)and terahertz(THz)communications are pivotal candidate technologies for supporting the development of 6G mobile networks.However,these techniques invalidate... Extremely large-scale multiple-input multiple-output(XL-MIMO)and terahertz(THz)communications are pivotal candidate technologies for supporting the development of 6G mobile networks.However,these techniques invalidate the common assumptions of far-field plane waves and introduce many new properties.To accurately understand the performance of these new techniques,spherical wave modeling of near-field communications needs to be applied for future research.Hence,the investigation of near-field communication holds significant importance for the advancement of 6G,which brings many new and open research challenges in contrast to conventional far-field communication.In this paper,we first formulate a general model of the near-field channel and discuss the influence of spatial nonstationary properties on the near-field channel modeling.Subsequently,we discuss the challenges encountered in the near field in terms of beam training,localization,and transmission scheme design,respectively.Finally,we point out some promising research directions for near-field communications. 展开更多
关键词 near-field communications extremely large-scale antenna arrays spatial non-stationarity beam training LOCALIZATION
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Near-Field Wireless Power Transfer, Sensing and Communication with Bessel Beams
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作者 CAO Xinghan YIN Huarui YOU Changsheng 《ZTE Communications》 2024年第1期53-61,共9页
The Bessel beam,characterized by its unique non-diffracting properties,holds promising applications.In this paper,we provide a detailed introduction and investigation into the theory and research of the Bessel beam,wi... The Bessel beam,characterized by its unique non-diffracting properties,holds promising applications.In this paper,we provide a detailed introduction and investigation into the theory and research of the Bessel beam,with a special focus on its generation and applications in the near-field region.We provide an introduction to the concepts,properties,and foundational theories of the Bessel beam.Additionally,the current study on generating Bessel beams and their applications is categorized and discussed,and potential research challenges are proposed in this paper.This review serves as a solid foundation for researchers to understand the concept of the Bessel beam and explore its potential applications. 展开更多
关键词 Bessel beams near-field non-diffractive beams beam synthesis technology
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Near-Field Beam Training for Holographic MIMO Communications: Typical Methods, Challenges and Future Directions
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作者 SHEN Jiayu YANG Jun +2 位作者 ZHU Chen DENG Zhiji HUANG Chongwen 《ZTE Communications》 2024年第1期41-52,共12页
Holographic multiple-input multiple-output(HMIMO)has become an emerging technology for achieving ultra-high frequency spectral efficiency and spatial resolution in future wireless systems.The increasing antenna apertu... Holographic multiple-input multiple-output(HMIMO)has become an emerging technology for achieving ultra-high frequency spectral efficiency and spatial resolution in future wireless systems.The increasing antenna aperture leads to a more significant characterization of the spherical wavefront in near-field communications in HMIMO scenarios.Beam training as a key technique for wireless communication is worth exploring in this near-field scenario.Compared with the widely researched far-field beam training,the increased dimensionality of the search space for near-field beam training poses a challenge to the complexity and accuracy of the proposed algorithm.In this paper,we introduce several typical near-field beam training methods:exhaustive beam training,hierarchical beam training,and multi-beam training that includes equal interval multi-beam training and hash multi-beam training.The performances of these methods are compared through simulation analysis,and their effectiveness is verified on the hardware testbed as well.Additionally,we provide application scenarios,research challenges,and potential future research directions for near-field beam training. 展开更多
关键词 holographic multiple-input multiple-output(HMIMO) beam training near-field equal interval multi-beam(EIMB)training hash multi-beam(HMB)training
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Modular Extremely Large-Scale Array Communication:Near-Field Modelling and Performance Analysis 被引量:2
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作者 Xinrui Li Haiquan Lu +2 位作者 Yong Zeng Shi Jin Rui Zhang 《China Communications》 SCIE CSCD 2023年第4期132-152,共21页
This paper investigates the wireless communication with a novel architecture of antenna arrays,termed modular extremely large-scale array(XLarray),where array elements of an extremely large number/size are regularly m... This paper investigates the wireless communication with a novel architecture of antenna arrays,termed modular extremely large-scale array(XLarray),where array elements of an extremely large number/size are regularly mounted on a shared platform with both horizontally and vertically interlaced modules.Each module consists of a moderate/flexible number of array elements with the inter-element distance typically in the order of the signal wavelength,while different modules are separated by the relatively large inter-module distance for convenience of practical deployment.By accurately modelling the signal amplitudes and phases,as well as projected apertures across all modular elements,we analyse the near-field signal-to-noise ratio(SNR)performance for modular XL-array communications.Based on the non-uniform spherical wave(NUSW)modelling,the closed-form SNR expression is derived in terms of key system parameters,such as the overall modular array size,distances of adjacent modules along all dimensions,and the user's three-dimensional(3D)location.In addition,with the number of modules in different dimensions increasing infinitely,the asymptotic SNR scaling laws are revealed.Furthermore,we show that our proposed near-field modelling and performance analysis include the results for existing array architectures/modelling as special cases,e.g.,the collocated XL-array architecture,the uniform plane wave(UPW)based far-field modelling,and the modular extremely large-scale uniform linear array(XL-ULA)of onedimension.Extensive simulation results are presented to validate our findings. 展开更多
关键词 modular extremely large-scale array practical deployment projected apertures non-uniform spherical wave near-field modelling
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The simulation of far-field wavelets using frequency- domain air-gun array near-field wavelets 被引量:1
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作者 宋建国 邓勇 同昕鑫 《Applied Geophysics》 SCIE CSCD 2013年第4期461-468,512,共9页
Air-gun arrays are used in marine-seismic exploration. Far-field wavelets in subsurface media represent the stacking of single air-gun ideal wavelets. We derived single air-gun ideal wavelets using near-field wavelets... Air-gun arrays are used in marine-seismic exploration. Far-field wavelets in subsurface media represent the stacking of single air-gun ideal wavelets. We derived single air-gun ideal wavelets using near-field wavelets recorded from near-field geophones and then synthesized them into far-field wavelets. This is critical for processing wavelets in marine- seismic exploration. For this purpose, several algorithms are currently used to decompose and synthesize wavelets in the time domain. If the traveltime of single air-gun wavelets is not an integral multiple of the sampling interval, the complex and error-prone resampling of the seismic signals using the time-domain method is necessary. Based on the relation between the frequency-domain phase and the time-domain time delay, we propose a method that first transforms the real near-field wavelet to the frequency domain via Fourier transforms; then, it decomposes it and composes the wavelet spectrum in the frequency domain, and then back transforms it to the time domain. Thus, the resampling problem is avoided and single air-gun wavelets and far-field wavelets can be reliably derived. The effect of ghost reflections is also considered, while decomposing the wavelet and removing the ghost reflections. Modeling and real data processing were used to demonstrate the feasibility of the proposed method. 展开更多
关键词 Air-gun array frequency domain near-field wavelet ghost removal far-field wavelet
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Codebook Design and Beam Training for Extremely Large-Scale RIS:Far-Field or Near-Field? 被引量:11
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作者 Xiuhong Wei Linglong Dai +2 位作者 Yajun Zhao Guanghui Yu Xiangyang Duan 《China Communications》 SCIE CSCD 2022年第6期193-204,共12页
Reconfigurable intelligent surface(RIS)is more likely to develop into extremely large-scale RIS(XL-RIS)to efficiently boost the system capacity for future 6 G communications.Beam training is an effective way to acquir... Reconfigurable intelligent surface(RIS)is more likely to develop into extremely large-scale RIS(XL-RIS)to efficiently boost the system capacity for future 6 G communications.Beam training is an effective way to acquire channel state information(CSI)for XL-RIS.Existing beam training schemes rely on the far-field codebook.However,due to the large aperture of XL-RIS,the scatters are more likely to be in the near-field region of XL-RIS.The far-field codebook mismatches the near-field channel model.Thus,the existing far-field beam training scheme will cause severe performance loss in the XL-RIS assisted nearfield communications.To solve this problem,we propose the efficient near-field beam training schemes by designing the near-field codebook to match the nearfield channel model.Specifically,we firstly design the near-field codebook by considering the near-field cascaded array steering vector of XL-RIS.Then,the optimal codeword for XL-RIS is obtained by the exhausted training procedure.To reduce the beam training overhead,we further design a hierarchical nearfield codebook and propose the corresponding hierarchical near-field beam training scheme,where different levels of sub-codebooks are searched in turn with reduced codebook size.Simulation results show the proposed near-field beam training schemes outperform the existing far-field beam training scheme. 展开更多
关键词 extremely large-scale RIS near-field codebook design beam training
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Polymer nanofibers prepared by low-voltage near-field electrospinning 被引量:6
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作者 郑杰 龙云泽 +5 位作者 孙彬 张志华 邵峰 张红娣 张志明 黄家寅 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第4期20-25,共6页
Elcctrospiiming is a straightforward method to produce micro/nanoscale fibers from polymer solutions typically using an operating voltage of 10 kV 30 kV and spinning distance of 10 cm 20 cm. In this paper, polyvinyl p... Elcctrospiiming is a straightforward method to produce micro/nanoscale fibers from polymer solutions typically using an operating voltage of 10 kV 30 kV and spinning distance of 10 cm 20 cm. In this paper, polyvinyl pyrrolidone (PVP) non-woven nanofibers with diameters of 200 nm 900 nm were prepared by low-voltage near-field electrospinning with a working voltage of less than 2.8 kV and a spinning distance of less than 10 mm. Besides the uniform fibers, beaded-fibers were also fabricated and the formation mechanism was discussed. Particularly, a series of experiments were carried out to explore the influence of processing variables on the formation of near-field electrospun PVP nanofibers, including concentration, humidity, collecting position, and spinning distance. 展开更多
关键词 NANOFIBERS near-field electrospinning beaded-fibers
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The 2018 M_S 5.9 Mojiang Earthquake:Source model and intensity based on near-field seismic recordings 被引量:4
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作者 Xu Zhang Zhen Fu +2 位作者 LiSheng Xu ChunLai Li Hong Fu 《Earth and Planetary Physics》 CSCD 2019年第3期268-281,共14页
On September 8, 2018, an M_S 5.9 earthquake struck Mojiang, a county in Yunnan Province, China. We collect near-field seismic recordings(epicentral distances less than 200 km) to relocate the mainshock and the aftersh... On September 8, 2018, an M_S 5.9 earthquake struck Mojiang, a county in Yunnan Province, China. We collect near-field seismic recordings(epicentral distances less than 200 km) to relocate the mainshock and the aftershocks within the first 60 hours to determine the focal mechanism solutions of the mainshock and some of the aftershocks and to invert for the finite-fault model of the mainshock.The focal mechanism solution of the mainshock and the relocation results of the aftershocks constrain the mainshock on a nearly vertical fault plane striking northeast and dipping to the southeast. The inversion of the finite-fault model reveals only a single slip asperity on the fault plane. The major slip is distributed above the initiation point, ~14 km wide along the down-dip direction and ~14 km long along the strike direction, with a maximal slip of ~22 cm at a depth of ~6 km. The focal mechanism solutions of the aftershocks show that most of the aftershocks are of the strike-slip type, a number of them are of the normal-slip type, and only a few of them are of the thrust-slip type.On average, strike-slip is dominant on the fault plane of the mainshock, as the focal mechanism solution of the mainshock suggests, but when examined in detail, slight thrust-slip appears on the southwest of the fault plane while an obvious part of normal-slip appears on the northeast, which is consistent with what the focal mechanism solutions of the aftershocks display. The multiple types of aftershock focal mechanism solutions and the slip details of the mainshock both suggest a complex tectonic setting, stress setting, or both. The intensity contours predicted exhibit a longer axis trending from northeast to southwest and a maximal intensity of Ⅷ around the epicenter and in the northwest. 展开更多
关键词 2018 MS 5.9 Mojiang EARTHQUAKE near-field SEISMIC RECORDING finite-fault model INTENSITY prediction FOCAL mechanism solution
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NEAR-FIELD SOURCE LOCALIZATION METHOD AND APPLICATION USING THE TIME REVERSAL MIRROR TECHNIQUE 被引量:4
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作者 Fu Yongqing Jiang Yulei Liu Zhanya 《Journal of Electronics(China)》 2011年第4期531-538,共8页
In order to develop the acoustic keyboard for Personal Computer(PC),it is necessary to seek high-precision near-field source localization algorithm for identifying the keyboard characters.First of all,the focusing pro... In order to develop the acoustic keyboard for Personal Computer(PC),it is necessary to seek high-precision near-field source localization algorithm for identifying the keyboard characters.First of all,the focusing property of Time Reversal Mirror(TRM) is introduced,and then a mathe-matical model of microphone array receiving typing sound is established according to the realization of acoustic keyboard from which the TRM localization algorithm is carried out.The results through computer simulation show that the localization Root Mean Square Error(RMSE) performance of the algorithm can reach 10-3,which demonstrates that the algorithm possesses a high accuracy for the actual near-field acoustic source localization,with potential of developing the computer acoustic keyboard.Furthermore,for the purpose of testing its effect on actual near-field source localization,we organize three experiments for acoustic keyboard characters localization.The experiment results show that the positioning error of TRM algorithm is less than 1 cm within a provided acoustic keyboard region.This will provide theoretical guidance for the further research of computer acoustic keyboard. 展开更多
关键词 Time reversal near-field source LOCATION Acoustic keyboard
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Near-field surface deformation during the April 20,2013,Ms7.0 Lushan earthquake measured by 1-Hz GNSS 被引量:3
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作者 Liu Gang Zhao Bin +5 位作者 Zhang Rui Huang Yong Wang Jun Nie Zhaosheng Qiao Xuejun Tan Kai 《Geodesy and Geodynamics》 2013年第2期1-5,共5页
The April 20, 2013, Ms7.0 Lushan earthquake was successfully recorded by closely spaced Continuous Global Positioning System (CGPS) stations owned by the Crustal Movement Observation Network of Chi- na (CMONC). Th... The April 20, 2013, Ms7.0 Lushan earthquake was successfully recorded by closely spaced Continuous Global Positioning System (CGPS) stations owned by the Crustal Movement Observation Network of Chi- na (CMONC). The 1-Hz GNSS data from eight CGPS stations, which are located between 30 km and 200 km from the hypocenter, were processed within quasi-real-time. The near-field surface deformation indicated the following characteristics : the near-field movements were limited to several centimeters ; the peak of the deformation wave was significantly larger than the static permanent offset; at the beginning of the event, the north wall of the fault moved to the southeast as the south wall moved to the southwest ; station SCTQ, which was the closest station to the hypocenter at 30 km, had the largest static permanent displacement of 2 cm; the peaks of the deformation waves were 1.5 cm, 5 cm and 3 cm, to the east, the south and vertically upward, respectively ; and the peaks of velocity and acceleration, derived from the deformation, were 3.4 cm/s and 5.3 cm/s^2,respectively. 展开更多
关键词 Ms7.0 Lushan earthquake CMONC 1-Hz GNSS near-field surface deformation
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The September 16, 2015 Mw 8.3 Illapel, Chile Earthquake: characteristics of tsunami wave from near-field to far-field 被引量:2
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作者 REN Zhiyuan YUAN Ye +3 位作者 WANG Peitao FAN Tingting WANG Juncheng HOU Jingming 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第5期73-82,共10页
On September 16, 2015, an earthquake with magnitude ofMw 8.3 occurred 46 km offshore from Illapel, Chile, generating a 4.4-m local tsunami measured at Coquimbo. In this study, the characteristics of tsunami are presen... On September 16, 2015, an earthquake with magnitude ofMw 8.3 occurred 46 km offshore from Illapel, Chile, generating a 4.4-m local tsunami measured at Coquimbo. In this study, the characteristics of tsunami are presented by a combination of analysis of observations and numerical simulation based on sources of USGS and NOAA. The records of 16 DART buoys in deep water, ten tidal gauges along coasts of near-field, and ten coastal gauges in the far-field are studied by applying Fourier analyses. The numerical simulation based on nonlinear shallow water equations and nested grids is carried out to provide overall tsunami propagation scenarios, and the results match well with the observations in deep water and but not well in coasts closed to the epicenter. Due to the short distance to the epicenter and the shelf resonance of southern Peru and Chile, the maximum amplitude ranged from 0.1 m to 2 m, except for Coquimbo. In deep water, the maximum amplitude of buoys decayed from 9.8 cm to 0.8 cm, suggesting a centimeter-scale Pacific-wide tsunami, while the governing period was 13-17 min and 32 min. Whereas in the far-field coastal region, the tsunami wave amplified to be around 0.2 m to 0.8 m, mostly as a result of run-up effect and resonance from coast reflection. Although the tsunami was relatively moderate in deep water, it still produced non-negligible tsunami hazards in local region and the coasts of farfield. 展开更多
关键词 2015 Illapel earthquake tsunami observation numerical modeling FAR-FIELD near-field
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Decoupling technique of patch antenna arrays with shared substrate by suppressing near-field magnetic coupling using magnetic metamaterials 被引量:2
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作者 柳兆堂 王甲富 +4 位作者 屈绍波 张介秋 马华 徐卓 张安学 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第4期398-403,共6页
In this paper,we propose the decoupling technique of patch antenna array by suppressing near-field magnetic coupling(NFMC) using magnetic metamaterials.To this end,a highly-integrated magnetic metamaterials,the subs... In this paper,we propose the decoupling technique of patch antenna array by suppressing near-field magnetic coupling(NFMC) using magnetic metamaterials.To this end,a highly-integrated magnetic metamaterials,the substrate-integrated split-ring resonator(SI-SRR),is firstly proposed to achieve negative permeability at the antenna operating frequency.By integrating SI-SRR in between two closely spaced antennas,magnetic fields are blocked in the shared substrate due to negative permeability of SI-SRR,reducing NFMC between the two antennas.To verify the technique,a prototype was fabricated and measured.The measured results demonstrated that the isolation can be enhanced by more than 17 dB even when the gap between the two patch antennas is only about 0.067 A.Due to high integration,this technique provides an effective alternative to high-isolation antenna array. 展开更多
关键词 antenna isolation antenna array near-field magnetic coupling magnetic metamaterials negative permeability
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Near-field radiative heat transfer in hyperbolic materials 被引量:3
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作者 Ruiyi Liu Chenglong Zhou +3 位作者 Yong Zhang Zheng Cui Xiaohu Wu Hongliang Yi 《International Journal of Extreme Manufacturing》 SCIE EI CAS 2022年第3期26-47,共22页
In the post-Moore era, as the energy consumption of micro-nano electronic devices rapidly increases, near-field radiative heat transfer(NFRHT) with super-Planckian phenomena has gradually shown great potential for app... In the post-Moore era, as the energy consumption of micro-nano electronic devices rapidly increases, near-field radiative heat transfer(NFRHT) with super-Planckian phenomena has gradually shown great potential for applications in efficient and ultrafast thermal modulation and energy conversion. Recently, hyperbolic materials, an important class of anisotropic materials with hyperbolic isofrequency contours, have been intensively investigated. As an exotic optical platform, hyperbolic materials bring tremendous new opportunities for NFRHT from theoretical advances to experimental designs. To date, there have been considerable achievements in NFRHT for hyperbolic materials, which range from the establishment of different unprecedented heat transport phenomena to various potential applications. This review concisely introduces the basic physics of NFRHT for hyperbolic materials, lays out the theoretical methods to address NFRHT for hyperbolic materials, and highlights unique behaviors as realized in different hyperbolic materials and the resulting applications. Finally, key challenges and opportunities of the NFRHT for hyperbolic materials in terms of fundamental physics, experimental validations, and potential applications are outlined and discussed. 展开更多
关键词 near-field radiative heat transfer hyperbolic materials photon tunneling hyperbolic phonon polaritons
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A novel phase-sensitive scanning near-field optical microscope 被引量:2
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作者 武晓宇 孙琳 +1 位作者 谭峭峰 王佳 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第5期346-351,共6页
Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and f... Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and further affects the intensity distribution. In recent years, the designs of surface plasmon polariton (SPP) devices have mostly been based on the phase modulation and manipulation. Here we demonstrate a phase sensitive multi-parameter heterodyne scanning near-field opti- cal microscope (SNOM) with an aperture probe in the visible range, with which the near field optical phase and amplitude distributions can be simultaneously obtained. A novel architecture combining a spatial optical path and a fiber optical path is employed for stability and flexibility. Two kinds of typical nano-photonic devices are tested with the system. With the phase-sensitive SNOM, the phase and amplitude distributions of any nano-optical field and localized field generated with any SPP nano-structures and irregular phase modulation surfaces can be investigated. The phase distribution and the interference pattern will help us to gain a better understanding of how light interacts with SPP structures and how SPP waves generate, localize, convert, and propagate on an SPP surface. This will be a significant guidance on SPP nano-structure design and optimization. 展开更多
关键词 phase detection scanning near-field optical microscope (SNOM) heterodyne interferometry surface plasmon polariton (SPP) devices
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Near-field 3D imaging approach combining MJSR and FGG-NUFFT 被引量:3
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作者 WANG Shuzhen FANG Yang +2 位作者 ZHANG Jin’gang LUO Mingshi LI Qing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第6期1096-1109,共14页
A near-field three-dimensional(3 D)imaging method combining multichannel joint sparse recovery(MJSR)and fast Gaussian gridding nonuniform fast Fourier transform(FGGNUFFT)is proposed,based on a perfect combination of t... A near-field three-dimensional(3 D)imaging method combining multichannel joint sparse recovery(MJSR)and fast Gaussian gridding nonuniform fast Fourier transform(FGGNUFFT)is proposed,based on a perfect combination of the compressed sensing(CS)theory and the matched filtering(MF)technique.The approach has the advantages of high precision and high efficiency:multichannel joint sparse constraint is adopted to improve the problem that the images recovered by the single channel imaging algorithms do not necessarily share the same positions of the scattering centers;the CS dictionary is constructed by combining MF and FGG-NUFFT,so as to improve the imaging efficiency and memory requirement.Firstly,a near-field 3 D imaging model of joint sparse recovery is constructed by combining the MF-based imaging method.Secondly,FGG-NUFFT and reverse FGG-NUFFT are used to replace the interpolation and Fourier transform in MF-based imaging methods,and a sensing matrix with high precision and high efficiency is constructed according to the traditional imaging process.Thirdly,a fast imaging recovery is performed by using the improved separable surrogate functionals(SSF)optimization algorithm,only with matrix and vector multiplication.Finally,a 3 D imagery of the near-field target is obtained by using both the horizontal and the pitching interferometric phase information.This paper contains two imaging models,the only difference is the sub-aperture method used in inverse synthetic aperture radar(ISAR)imaging.Compared to traditional CS-based imaging methods,the proposed method includes both forward transform and inverse transform in each iteration,which improves the quality of reconstruction.The experimental results show that,the proposed method improves the imaging accuracy by about O(10),accelerates the imaging speed by five times and reduces the memory usage by about O(10~2). 展开更多
关键词 interference imaging joint sparse recovery compressed sensing(CS) matching filtering(MF) fast Gaussian gridding nonuniform fast Fourier transform(NUFFT) near-field 3D imaging
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