- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Gas Sensing Characterization of Single-Nanowire Sensor Array Systems Based on Non-Functionalized and Pt-Functionalized Tungsten Oxide
摘要： Here we present the gas sensing characterization of single-nanowire sensor array systems based on either non-functionalized or Pt-functionalized single tungsten oxide nanowires towards various concentrations of nitrogen dioxide and ethanol. The sensor systems demonstrate stable and reproducible responses to the tested analytes, showing consistency with previous systems based on multiple-nanowire based films and validating the fabrication process of these devices.
关键词： sensor array,single-nanowire,tungsten oxide,gas sensing
更新于2025-09-09 09:28:46
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Single Nanostructured Gold Amalgam Microelectrode Electrochemiluminescence: From Arrays to a Single Point
摘要： Here we show a technique to prepare an array of Au nanostructured electrodes by selective co-deposition of AuxHgy with subsequent electrochemical dealloying of Hg resulting in branched microstructures with Hg free surface ≈824×greater with respect to the original area defined by lithography. We studied the kinetics of the electrochemoluminescence reaction using the Ru(bpy)3 2+ based system. The microstructured nontoxic AuxHgy can also find numerous applications in electrochemistry, especially for DNA and proteins.
关键词： array of microelectrodes,electrochemiluminescence,dealloying,single-spot observation,gold amalgam
更新于2025-09-09 09:28:46
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An Electronically Mode Reconfigurable Orbital Angular Momentum Array Antenna
摘要： In this paper, an array antenna for generating multi-mode orbital angular momentum (OAM) vortex waves and having electrically controlled mode reconfigurable function is proposed. The proposed antenna is based on a reconfigurable feed network (RFN) consisting of multiple PIN diodes as reconfigurable switches, a direct current (dc) control board and a 2 × 4 radial uniform circular array. By controlling the coding sequence of the corresponding PIN diode dc bias voltage on the RFN using a programmable microcontroller, the OAM modes generated by the proposed antenna can be dynamically reconfigured between l = 0, ±1, and ±2. Moreover, the OAM beams can be generated in a wide frequency band of 5.5–6.1 GHz and 5.65–6.1GHz for l = ± 1, ±2 modes and l = 0 mode, respectively. The prototype of the proposed antenna is simulated and fabricated to validate the proposed design. Both far-field and near-field experiments were performed to verify the feasibility of the proposed design. The results of the numerical simulation and measurement have good agreement with each other.
关键词： orbital angular momentum (OAM),array antenna,Reconfigurable,PIN diodes
更新于2025-09-09 09:28:46
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Effect of CsI(Tl) micro-conical-frustums on the performance of the pixelated CsI(Tl) scintillation screen in X-ray imaging
摘要： The pixelated CsI(Tl) scintillation screen based on oxidized silicon micro-pore array template with CsI(Tl) micro-conical-frustums (CMCF) was proposed. The effect of the CMCF on the performance of the pixelated CsI(Tl) scintillation screen in X-ray imaging was studied by using Geant4 Monte Carlo simulation code. The variations of the light output (LO), modulation transfer function (MTF) and detective quantum efficiency (DQE) for the screen with the cone angle β of the CMCF in X-ray imaging were revealed. The results show that the LO of the pixelated scintillation screen with CMCF is superior to that of the screens with CsI(Tl) micro-cylinders (CMC) or with reversed CsI(Tl) micro-conical-frustums (RCMCF), but the spatial resolution of the X-ray imaging system by using the pixelated scintillation screen with RCMCF is better than that by using the screens with CMCF or with CMC. At low frequency, the cone angle β corresponding to DQEs from good to bad are 2.40°, 0.00° and -2.40°. But at high frequency, the cone angle β corresponding to DQEs from good to bad change to 2.40°, -2.40° and 0.00°. The reason is that, for a pixelated scintillation screen, the DQE for the screen not only depends on the efficiency of X-ray absorption, but also depends on the number of scintillation photons exiting the bottom the screen per interacting X-ray photon and its Poisson excess, and MTF. The simulated results of DQEs show that the comprehensive performance of the pixelated CsI(Tl) screen with CMCF in X-ray imaging is better than that of the screens with CMC or with CRMCF.
关键词： Shape of CsI(Tl) micro-conical-frustum,Performance in X-ray imaging,Oxidized silicon micro-pore array template,Pixelated CsI(Tl) scintillation screen
更新于2025-09-09 09:28:46
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Study of Horizontally Polarized Omnidirectional Microstrip Antenna Arrays
摘要： This paper presents two microstrip antenna arrays for horizontally polarized (HP) omnidirectional application, namely rectangular patch antenna array and H-shaped patch antenna array. There are eight patch elements placed with back-to-back structure, four patch elements on each side. Antenna arrays are fed by a split eight power divider. The H-shaped patch antenna array has better omnidirectional performance than rectangular patch antenna array. The H-shaped antenna array is fabricated and measured. Both simulated and measured results show that the bandwidth of the designed H-shaped antenna array is 36 MHz with a center frequency 2.35 GHz. Horizontally polarized gains are greater than 7 dBi over the resonant band (S11 < ?10 dB), while the cross-polarization level is less than ?25 dB. The proposed H-shaped antenna array has high directivity (half-power beam-width is only 20 deg) and good omnidirectional performance (gain variation less than 1.5 dBi) at the center frequency.
关键词： horizontal polarization,omnidirectional radiation pattern,microstrip antenna,Antenna array
更新于2025-09-09 09:28:46
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A SIMPLE 2×3 BEAM-FORMING NETWORK WITH A 2-BIT PHASE SHIFTER FOR FOUR-BEAM RECONFIGURATION
摘要： A simple 2×3 recon?gurable beam-forming network (R-BFN) for four-beam recon?guration application is designed and implemented. The proposed R-BFN with two input ports and three output ports consists of a 2:1 power divider, a 90? hybrid, a 180? hybrid and a 2-bit phase shifter. The 2-bit phase shifter has two states: one is a 180? phase shifter (State 1); the other is a 0?/360? phase shifter (State 2). By introducing the 2-bit phase shifter, the constant phase di?erences of three output ports can be recon?gured. When the proposed R-BFN is connected to an antenna array, a four-beam recon?guration is obtained. Simulated and measured results show that good impedance matching, high port isolation, equal power division, and constant phase di?erence have been achieved simultaneously within the operation band of 2.4–2.6 GHz. The capability of the proposed R-BFN to recon?gure beams is also veri?ed experimentally by using a 2.5 GHz dipole array.
关键词： antenna array,phase shifter,recon?guration,beam-forming network
更新于2025-09-09 09:28:46
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Three-Dimensional Holographic Electromagnetic Imaging for Accessing Brain Stroke
摘要： The authors recently developed a two-dimensional (2D) holographic electromagnetic induction imaging (HEI) for biomedical imaging applications. However, this method was unable to detect small inclusions accurately. For example, only one of two inclusions can be detected in the reconstructed image if the two inclusions were located at the same XY plane but in different Z-directions. This paper provides a theoretical framework of three-dimensional (3D) HEI to accurately and effectively detect inclusions embedded in a biological object. A numerical system, including a realistic head phantom, a 16-element excitation sensor array, a 16-element receiving sensor array, and image processing model has been developed to evaluate the effectiveness of the proposed method for detecting small stroke. The achieved 3D HEI images have been compared with 2D HEI images. Simulation results show that the 3D HEI method can accurately and effectively identify small inclusions even when two inclusions are located at the same XY plane but in different Z-directions. This preliminary study shows that the proposed method has the potential to develop a useful imaging tool for the diagnosis of neurological diseases and injuries in the future.
关键词： brain stroke,sensor array,dielectric properties,electromagnetic induction imaging,magnetic induction tomography
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Towards a Framework for Offering Remote Sensing Data in an Analysis-Ready Format
摘要： Diverse storage formats, archive dispersal, and inconsistent naming make it difficult for researchers and the general public to find and access remote sensing data. To facilitate the use of remote sensing data, this paper provides an integrated framework for direct reading remote sensing data in a widely compatible and analysis-ready format, NumPy ndarray. The framework is composed of two main components. One is the raster data processing and storage model. All the operational gridded remote sensing data are split into tiles, and reorganized in n-dimensional array. Then the N-Dimensional data array is serialized into netCDF and stored into distributed file system. The other is the spatiotemporal filter to achieve parallel query, and it has been encapsulated into Internet-accessible application programming interfaces (APIs). The scenario of calculating NDVI of a specified spatiotemporal range given at last illustrate the efficiency and convenience of our platform provided for remote sensing data analysis.
关键词： remote sensing data,spatiotemporal retrieval,multi-dimensional array,analysis-ready format
更新于2025-09-09 09:28:46
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - An On-Board Differential Patch Array for 79 GHz Single-Channel Radar Applications
摘要： This paper demonstrates the design and characterization of an on-board 4x2 corporate-fed differential patch array at 79 GHz band to equip a fully differential millimeter-wave radar transceiver. The array is based on two single-ended 4x1 arrays and it has a measured peak gain of more than 14 dBi over the 77-81 GHz band with a simulated efficiency of more than 60%.
关键词： differential,antenna,array,radar,millimeter-wave
更新于2025-09-09 09:28:46
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MUTUAL COUPLING REDUCTION BETWEEN PRINTED DUAL-FREQUENCY ANTENNA ARRAYS
摘要： A new defected ground structure (DGS) is designed to reduce the mutual coupling of a dual-frequency printed monopole array. The designed dual-frequency DGS consists of two concentric split ring slots. Each split ring slot produces band rejection characteristics at one resonant frequency of the antennas. An e?ective equivalent circuit model of the DGS section is proposed with the circuit parameters successfully extracted. Good agreement exists among the circuit simulation, EM simulation and experimental results. With the inclusion of the DGS, the measured mutual coupling of the dual-band array has been e?ectively reduced by 10 dB and 20 dB at two resonant frequencies, respectively.
关键词： dual-frequency printed monopole array,equivalent circuit model,defected ground structure (DGS),mutual coupling reduction
更新于2025-09-09 09:28:46