检索结果-南通市图书馆

Terahertz wide-angle metalens with nearly ideal object-image relation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第1期22卷 147-152页

作者：王宇程洁嵘冀允允范飞常胜江 Institute of Modern Optics Nankai UniversityTianjin 300350China tianjin key laboratory of Micro-scale Optical information Science and Technology Tianjin 300350China tianjin key laboratory of Optoelectronic Sensor and sensing Network Technology Tianjin 300350China

Metalenses are essential components in terahertz imaging ***,without careful design,they show limited field of view and their practical applications are ***,a wide-angle metalens is proposed whose structure is optimized for focusing within the incident angles of±25°.Simulation and experiment results show that the focusing efficiency,spot size,and modulation transfer function of this lens are not sensitive to the incident *** importantly,this wide-angle metalens follows the ideal Gaussian formula for the object-image relation,which ensures a wider field of view and better contrast in the imaging experiment.

关键词： terahertz metalens wide-angle Gaussian formula

Coexisting fast–slow dendritic traveling waves in a 3D-array electric field coupled neuronal network

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第6期33卷 614-626页

作者：魏熙乐任泽宇卢梅丽樊亚琴常思远 The tianjin key laboratory of Process Measurement and control School of Electrical and Information EngineeringTianjin UniversityTianjin 300072China School of information Technology Engineering Tianjin University of Technology and EducationTianjin 300074China

Coexistence of fast and slow traveling waves without synaptic transmission has been found in hhhippocampal tissues,which is closely related to both normal brain activity and abnormal neural activity such as epileptic discharge. However, the propagation mechanism behind this coexistence phenomenon remains unclear. In this paper, a three-dimensional electric field coupled hippocampal neural network is established to investigate generation of coexisting spontaneous fast and slow traveling waves. This model captures two types of dendritic traveling waves propagating in both transverse and longitude directions: the N-methyl-D-aspartate(NMDA)-dependent wave with a speed of about 0.1 m/s and the Ca-dependent wave with a speed of about 0.009 m/s. These traveling waves are synaptic-independent and could be conducted only by the electric fields generated by neighboring neurons, which are basically consistent with the in vitro data measured experiments. It is also found that the slow Ca wave could trigger generation of fast NMDA waves in the propagation path of slow waves whereas fast NMDA waves cannot affect the propagation of slow Ca waves. These results suggest that dendritic Ca waves could acted as the source of the coexistence fast and slow waves. Furthermore, we also confirm the impact of cellular spacing heterogeneity on the onset of coexisting fast and slow waves. The local region with decreasing distances among neighbor neurons is more liable to promote the onset of spontaneous slow waves which, as sources, excite propagation of fast waves. These modeling studies provide possible biophysical mechanisms underlying the neural dynamics of spontaneous traveling waves in brain tissues.

关键词： hippocampal network epileptiform dendritic oscillation traveling wave electric field coupling

Effect of applied electric fields on supralinear dendritic integration of interneuron

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第2期33卷 84-95页

作者：樊亚琴魏熙乐卢梅丽伊国胜 tianjin key laboratory of Process Measurement and control School of Electrical and Information EngineeringTianjin UniversityTianjin 300072China School of information Technology Engineering Tianjin University of Technology and EducationTianjin 300222China

Evidences show that electric fields(EFs)induced by the magnetic stimulation could modulates brain activities by regulating the excitability of GABAergic ***,it is still unclear how and why the EF-induced polarization affects the interneuron response as the interneuron receives NMDA synaptic *** the key role of NMDA receptor-mediated supralinear dendritic integration in neuronal computations,we suppose that the applied EFs could functionally modulate interneurons’response via regulating dendritic *** first,we build a simplified multi-dendritic circuit model with inhomogeneous extracellular potentials,which characterizes the relationship among EF-induced spatial polarizations,dendritic integration,and somatic *** performing model-based singular perturbation analysis,it is found that the equilibrium point of fast subsystem can be used to asymptotically depict the subthreshold input–output(sI/O)relationship of dendritic *** predicted that EF-induced strong depolarizations on the distal dendrites reduce the dendritic saturation output by reducing driving force of synaptic input,and it shifts the steep change of sI/O curve left by reducing stimulation threshold of triggering NMDA ***,the EF modulation prefers the global dendritic integration with asymmetric scatter distribution of NMDA ***,we identify the respective contribution of EF-regulated dendritic integration and EF-induced somatic polarization to an action potential generation and find that they have an antagonistic effect on AP generation due to the varied NMDA spike threshold under EF stimulation.

关键词： GABAergic interneuron electrical field supralinear dendritic integration action potential generation

Multi-sensor multispectral reconstruction framework based on projection and reconstruction

在线全文

学校读者我要写书评

暂无评论

Science China(information Sciences) 2024年第3期67卷 246-262页

作者： Tianshuai LI Tianzhu LIU Xian LI Yanfeng GU Yukun WANG Yushi CHEN School of Electronics and information Engineering Harbin Institute of Technology Heilongjiang Province key laboratory of Space-Air-Ground Integrated intelligent Remote sensing

The scarcity and low spatial resolution of hyperspectral images(HSIs) have become a major problem limiting the application of the images. In recent years, spectral reconstruction(SR) has been applied to convert multispectral images(MSIs) with abundant quantities and high spatial resolution into HSIs. With the launch of several new multispectral(MS) satellites with a short repeat period, the simultaneous acquisition of images from multiple MS sensors in the same area is gradually becoming feasible. Unfortunately, existing SR methods only consider the reconstruction of the MSIs of a single sensor without considering using MSIs from different MS sensors to obtain a better construction effect through their complementary bands. However,multi-sensor SR is characterized by two problems: inconsistency in the amplitude information of real multisensor imaging and difficulty in the extraction of the complex correlations of bands from different *** solve these problems, this paper proposes a multi-sensor SR framework based on a two-step approach in which the problems of amplitude inconsistency and band information extraction are solved using an ideal projection network and an ideal multi-sensor SR network, respectively. The effectiveness of the proposed method is verified by experiments on three datasets.

关键词： spectral reconstruction spectral superresolution hyperspectral image multispectral image neural networks multi-sensor

A column-shared histogramming TDC with pixel-to-pixel coincidence detection and compact analog counters for Flash LiDAR sensor

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(information Sciences) 2024年第8期67卷 345-346页

作者： Haoran WU Kaiming NIE Jiangtao XU Qinglong LIN Yingying JIAO School of Microelectronics Tianjin University tianjin key laboratory of Imaging and sensing Microelectronic Technology

In recent years, Flash LiDAR sensors based on direct timeof-flight(DToF) have been playing an increasingly important role in various 3D imaging fields. In order to perform a histogram on the chip to reduce the data rate, it is inevitable to use a large-size histogramming time-to-digital converter(hTDC) in a Flash LiDAR sensor. However, a large-size hTDC limits the spatial resolution of the sensor.

关键词： Pixels

Mutual aid instead of mutual restraint:interactive probing for topological charge and phase of a vortex beam of large aberrations

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2024年第1期12卷 172-182页

作者： SHENGYANG WU BENLI YU LEI ZHANG key laboratory of Opto-electronic information Acquisition and Manipulation Ministry of EducationAnhui UniversityHefei 230601China information Materials and intelligent sensing laboratory of Anhui Province Anhui UniversityHefei 230601China

An imperfect propagation environment or optical system would introduce wavefront aberrations to vortex *** phase aberrations and orbital angular momentum in a vortex beam are proved to be mutually restrictive in parameter *** make traditional topological charge(TC)probing methods ineffective while the phase singularity makes phase retrieval difficult due to the aliasing between the wrapped phase jump and the vortex phase *** interactive probing method is proposed to make measurements of the aberrated phase and orbital angular momentum in a vortex beam assist rather than hinder each *** phase unwrapping is liberated from the phase singularity by an annular shearing interference technique while the TC value is determined by a Moirétechnique immune to *** and experimental results proving the method effective are *** is of great significance to judge the characteristics of vortex beams passing through nonideal environments and optical systems.

关键词： vortex topological beam

State estimation for delayed switched positive systems: delayed radius approach

在线全文

学校读者我要写书评

暂无评论

Science China(information Sciences) 2024年第8期67卷 190-205页

作者： Weizhong CHEN Zhongyang FEI Xudong ZHAO Zheng-Guang WU School of Electronics and information Xi'an Polytechnic University Research Institute of intelligent control and Systems Harbin Institute of Technology key laboratory of intelligent control and Optimization for Industrial Equipment of Ministry of Education Dalian University of Technology School of control Science and Engineering Dalian University of Technology State key laboratory of Industrial control Technology Institute of Cyber-Systems and ControlZhejiang University

In this paper, an interval estimation scheme is developed for delayed switched positive systems（DSPS） with mode-dependent average dwell time switching. A lossless zonotopic estimation approach is proposed for the delayed intersection zonotope with the positive generator matrix. First, considering the existence of asynchronism between the system mode and the correction matrix mode, the mismatched intersection zonotope is constructed for DSPS to verify the consistency between the system model and ***, by utilizing the introduced radius definitions, the ?∞performance is addressed to optimize the size of delayed intersection zonotopes. Subsequently, we present a joint-design approach of switching signals and the mode-dependent correction matrix by constructing positive generator matrix-based delayed radius functions. Furthermore, guaranteed nonnegative state bounds are derived for the considered DSPS based on the proposed lossless zonotopic estimation criteria. Finally, detailed simulations are conducted to validate the feasibility and superiority of the developed methods.

关键词： delayed switched positive systems interval estimation asynchronous correction matrix zonotopes mode-dependent average dwell time

Research on embedded locally resonant metamaterials used for vibration attenuation of thin-walled workpieces in mirror milling

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2024年第8期40卷 1-16页

作者： Bei Ding Wei Wang Juliang Xiao Zhiqiang Wu Cheng Liu School of Mechanical Engineering Tianjin UniversityTianjin300350China tianjin key laboratory of Nonlinear Dynamics and control Tianjin300350China key laboratory of Modern Mechanisms and Equipment Design of the State Ministry of Education Tianjin UniversityTianjin300350China

The shell composed of large-scale parts is the essential component of mechanical structures in the aerospace,shipping,and railway *** workpieces are characterized by thin walls and weak rigidity,thus requiring an effective technology for high-performance ***,an embedded locally resonant metamaterial with double resonators is proposed and combined with the magnetic follow-up support technology to attenuate the vibration of thin-walled parts for the first *** band structures and parametric adjustment laws are systematically investigated and validated by analytical calculation and finite element method,which proves the proposed model is broadband,lightweight,and flexible in low *** characteristics,as well as the relatively simple structure,are unique advantages for thin-walled structure ***,mirror milling experiments have been performed to assess the slave module with the proposed *** the results,the root mean square amplitude of the thin-walled workpiece with the combined device decreases by nearly 9%,which means that the performance has been improved by the combined ***,this work provides an integrated and efficient solution for vibration suppression in thin-walled parts milling,which extends locally resonant metamaterials to practical engineering fields and helps to improve the status quo of mirror milling from the perspective of metamaterials.

关键词： Local resonance Band gap Thin-walled workpieces Vibration suppression

Circularly polarized lasing from chiral metal-organic frameworks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2024年第08期12卷 1654-1664页

作者： DEXIANG ZHU ZHOUYUANHANG WANG XIANGYU XU WENYU DU WEI HUANG YAN KUAI BENLI YU JIANZHONG ZHENG ZHIJIA HU SIQI LI information Materials and intelligent sensing laboratory of Anhui Province School of Physics and Optoelectronic Engineering Anhui University key laboratory of Opto-Electronic information Acquisition and Manipulation of Ministry of Education School of Environmental Science and Engineering Nanjing Tech University

Circularly polarized lasers play a pivotal role in classical optics, nanophotonics, and quantum optical information processing, while their fabrication remains complex. This article begins with examining the interactions between stimulated emission and chiral matter, outlining a simple strategy for producing circularly polarized lasing from chiral metal-organic frameworks(MOFs), such as the zeolitic imidazolate framework(ZIF), embedded with achiral laser dyes(L∕D-ZIF?dyes). It is found that the stimulated emission threshold and intensity are influenced by the interplay between the chiral polarization of the pump light and the inherent chirality of the MOF nanoparticles. We further present the design of a chiral vertical-cavity surface-emitting laser(VCSEL), comprising an L∕D-ZIF?dyes solid-state film sandwiched between a high-reflectivity distributed Bragg reflector(DBR) mirror and a silver film. The cavity-based lasing exhibits higher asymmetry between emitting left-handed and right-handed polarized light compared to chiral spontaneous emission(SE) and amplified spontaneous emission(ASE), with an asymmetry value glum of approximately ±0.31. This value is nearly four-fold greater than that of SE and twice that of ASE. Our findings reveal a new approach to amplify chiral signals, promoting the comprehension and application of chiral–matter interactions, and offering a simple yet effective strategy to fabricate chiral lasers.

关键词： Bragg reflectors Circular polarization Green fluorescent protein Laser dyes Optical materials Vertical cavity surface emitting lasers