- 标题
- 摘要
- 关键词
- 实验方案
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Enhanced photocatalytic performance of TiO2 NTs decorated with chrysanthemum-like BiOI nanoflowers
摘要： The BiOI nanosheets/chrysanthemum-like nanoflowers were successfully deposited on the surface of TiO2 nanotube arrays (TiO2 NTs) by the successive ionic layer adsorption and reaction (SILAR) method, and the morphology and visible light response of samples with different SILAR deposition cycles were investigated in detail. The as-prepared BiOI/TiO2 NTs significantly enhanced photoelectrocatalytic (PEC) activity for the removal of Methyl orange (MO), Rhodamine B (RhB), Methylene blue (MB) and Cr(VI). The as-prepared Sample-7 with chrysanthemum-like nanostructures showed the high visible light photocurrent density of 120.06 μA/cm2, photovoltage of ?203.61 mV/cm2, PEC efficiencies of 45%, 62%, 79% and 77% for the removal of MO, RhB, MB and Cr(VI), respectively. The high PEC performances could be ascribed to the excellent visible light response and charge carrier transportation in chrysanthemum-like BiOI nanoflowers. By further probing the charge separation and transportation behaviors, the experiments of the energy band structure and active species trapping were carried out. A possible p-n heterojunction photocatalytic mechanism was proposed, which not only benefited the efficient separation of photogenerated electrons but also demonstrated the advanced capacity for the PEC removal of organic dyes and heavy metal ions.
关键词： BiOI,Photoelectrochemical performance,TiO2 nanotube arrays,Nanoflowers
更新于2025-11-19 16:56:35
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Two-Dimensional Angle Estimation of Two-Parallel Nested Arrays Based on Sparse Bayesian Estimation
摘要： To increase the number of estimable signal sources, two-parallel nested arrays are proposed, which consist of two subarrays with M sensors, and can estimate the two-dimensional (2-D) direction of arrival (DOA) of M2 signal sources. To solve the problem of direction finding with two-parallel nested arrays, a 2-D DOA estimation algorithm based on sparse Bayesian estimation is proposed. Through a vectorization matrix, smoothing reconstruction matrix and singular value decomposition (SVD), the algorithm reduces the size of the sparse dictionary and data noise. A sparse Bayesian learning algorithm is used to estimate one dimension angle. By a joint covariance matrix, another dimension angle is estimated, and the estimated angles from two dimensions can be automatically paired. The simulation results show that the number of DOA signals that can be estimated by the proposed two-parallel nested arrays is much larger than the number of sensors. The proposed two-dimensional DOA estimation algorithm has excellent estimation performance.
关键词： decoupled estimation,direction of arrival estimation,degrees of freedom,sparse Bayesian learning,sparse arrays
更新于2025-09-23 15:23:52
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Lattice Zenneck Modes on Subwavelength Antennas
摘要： Optical resonances in isolated nanoparticles made out of commonly occurring materials with high optical losses, such as transition metal dichalcogenides, germanium, carbide, and others, are weak and not sufficient for field enhancement and competing with plasmonic resonances in noble metal nanoparticles. This work presents a novel approach to achieve strong resonances in the arrays of such nanoparticles with large optical losses and points to their potential for efficient light control in ultra-thin optical elements, sensing, and photovoltaic applications. Materials with large imaginary part of permittivity (LIPP) are studied and nanostructures of these materials are shown to support not only surfaces modes, known as Zenneck waves, but also modes localized on the subwavelength particle. This approach opens up the possibility of exciting strong localized nanoparticle resonances without involving plasmonic or high-refractive-index materials. Arranging LIPP particles in a periodic array plays a crucial role allowing for collective array resonances, which are shown to be much stronger in particle array than in single particle. The collective lattice resonances can be excited at the wavelength defined mainly by the array period and thus easily tuned in a broad spectral range not being limited by particle permittivity, size, or shape.
关键词： transition metal dichalcogenides,lattice resonance,Kerker effect,molybdenum diselenide,directional scattering,nanoparticle arrays
更新于2025-09-23 15:23:52
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Two-Dimensional Imaging Based on Near-Field Focused Array Antenna
摘要： In this letter, a near-field focused array antenna is applied to two-dimensional (2-D) microwave imaging, which steers its focus on the designed focal plane by changing the operating frequency and by phase control in two directions, respectively. The imaging system is composed of this array and two microstrip antennas, as receiver and transmitters, respectively. Simulations and measurements have proved the feasibility of the image reconstruction approach. The proposed method has a high imaging speed due to fast electrical beam scan, and thanks to the frequency scan performance of the array in one dimension, it also shows low-cost property against the fully phased method.
关键词： near-field focused beams,Microwave imaging,phased arrays,reconstruction algorithm
更新于2025-09-23 15:23:52
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Seed Free Growth of Aligned ZnO Nanowire Arrays on AZO Substrate
摘要： In the absence of commonly used seed layer, we can still successfully synthesized aligned ZnO nanowire arrays by the hydrothermal method. By using aluminum-doped zinc oxide (AZO) glass as a substrate, high-density and vertically aligned ZnO nanowires were synthesized directly on the substrate in the absence of the ZnO seed layer. The current-voltage curve indicated that the sample grown on AZO glass substrate in the absence of seed layer possesses better conductivity than that synthesized on FTO glass substrate with ZnO seed layer. Thus, a simplified, seed-free and low-cost experimental protocol was reported here for large-scale production of high quality ZnO nanowire arrays with promoted conductivity.
关键词： conductivity,ZnO nanowire arrays,seed layer free,AZO substrate
更新于2025-09-23 15:23:52
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Transparent, Flexible, Penetrating Microelectrode Arrays with Capabilities of Single-Unit Electrophysiology
摘要： Accurately mapping neuronal activity across brain networks is critical to understand behaviors, yet it is very challenging due to the need of tools with both high spatial and temporal resolutions. Here, penetrating arrays of flexible microelectrodes made of low-impedance nanomeshes are presented, which are capable of recording single-unit electrophysiological neuronal activity and at the same time, transparent, allowing to bridge electrical and optical brain mapping modalities. These 32 transparent penetrating electrodes with site area, 225 μm2, have a low impedance of ≈149 kΩ at 1 kHz, an adequate charge injection limit of ≈0.76 mC cm?2, and up to 100% yield. Mechanical bending tests reveal that the array is robust up to 1000 bending cycles, and its high transmittance of 67% at 550 nm makes it suitable for combining with various optical methods. A temporary stiffening using polyethylene glycol allows the penetrating nanomesh arrays to be inserted into the brain minimally invasively, with in vivo validation of recordings of spontaneous and evoked single-unit activity of neurons across layers of the mouse visual cortex. Together, these results establish a novel neurotechnology—transparent, flexible, penetrating microelectrode arrays—which possesses great potential for brain research.
关键词： transparent,spikes,microelectrode arrays,flexible,penetrating
更新于2025-09-23 15:23:52
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Bound states in the continuum in the double-period rectangular hole arrays perforated in one layer of photonic crystal slab in the visible wavelength region
摘要： We investigate optical bound states in the continuum (BICs) supported by a photonic crystal (PhC) slab penetrated with two periodic rectangular hole arrays embedded each other parallelly and vertically. It proves that the tunable off-Γ BICs can be found in the structure of both types, but the at-Γ BICs can only be obtained in the parallel structure. Quality factors (Q-factor) are obtained extremely high exceeding 105 for both types of structures. The tunable off-Γ BICs can be modulated by the structure parameters. Especially, the sensitivity of the resonant wavelength on the surrounding medium refractive index change is very large for the structure in both types, and tunable off-Γ BICs can be tuned by varying the environmental index. The results above accord well from the finite difference time domain method (FDTD) and the temporal coupled mode theory (CMT), which are beneficial to design practical resonance elements based on optical BICs in various new optical applications.
关键词： Double-periodic rectangular hole arrays,Photonic crystal,Fano resonance,Bound state in the continuum
更新于2025-09-23 15:23:52
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Direct Z-scheme MoSe2 decorating TiO2 nanotube arrays photocatalyst for water decontamination
摘要： Exploring a Z-scheme heterojunction photocatalyst with efficient charge separation and outstanding redox ability is necessary but very challenging. Herein, a novel direct Z-scheme MoSe2 decorating TiO2 nanotube arrays photocatalyst (denoted as MoSe2@TNTs) was prepared by a facile in situ hydrothermal method. Few-layer MoSe2 nanosheets distribute on the surface of the TNTs without shielding the tubular structure. Compared with individual TNTs and MoSe2, the as-prepared MoSe2@TNTs composite displays much better photocatalytic activity for eliminating pollutants (such as 4-nitrophenol and hexavalent chromium). Investigation results reveal that TNTs combined with appropriate amount of MoSe2 as co-catalyst has direct Z-scheme construction instead of traditional type-II heterojunction, which can offer abundant photo-generated active species with high redox capacity.
关键词： Photocatalysis,TiO2 nanotube arrays,Z-scheme,Molybdenum diselenide
更新于2025-09-23 15:23:52
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FPGA-Based Implementation of an Artificial Neural Network for Measurement Acceleration in BOTDA Sensors
摘要： In recent years, using distributed fiber-optic sensors based on Brillouin scattering, for monitoring pipelines, tunnels, and other constructional structures have gained huge popularity. However, these sensors have a low signal-to-noise ratio (SNR), which usually increases their measurement error. To alleviate this issue, ensemble averaging is used which improves the SNR but in return increases the measurement time. Reducing the noise by averaging requires hundreds or thousands of scans of the optical fiber; hence averaging is usually responsible for a large percent of the entire system latency. In this paper, we propose a novel method based on artificial neural network for SNR enhancement and measurement acceleration in distributed fiber-optic sensors based on the Brillouin scattering. Our method takes the noisy Brillouin spectrums and improves their SNR by 20 dB, which reduces the measurement time significantly. It also improves the accuracy of the Brillouin frequency shift estimation process and its latency by more than 50% in comparison with the state-of-the-art software and hardware solutions.
关键词： Artificial neural network (ANN),digital signal processing,optical fibers,curve fitting,field-programmable gate arrays (FPGAs)
更新于2025-09-23 15:23:52
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Hybrid Method for the Synthesis of Isophoric Phase-Shaped Beams
摘要： A novel hybrid approach to the power synthesis of mask-constrained shaped beams by means of concentric-ring isophoric arrays is presented. The basis of this procedure is to use the complex aperture distribution obtained by Elliott–Stern method as a starting point of an innovative algorithm that combines a classical density tapering method with a simulated annealing one. The proposed technique allows to outperform the previous procedures.
关键词： uniform distribution,shaped beams,Density tapering,sparse arrays
更新于2025-09-23 15:23:52