- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Self-powered, all-solution processed, trilayer heterojunction perovskite-based photodetectors
摘要： Heterostructures composed of nano-/micro-junctions, combining the excellent photon harvesting properties of nano-system and ultrafast carrier transfer of micro-system, have shown promising role in high-performance photodetectors. Here, in this paper a highly-sensitive trilayer in which the CdS nanorods (NRs) layer is sandwiched between ZnO/CsPbBr3 interface to reduce self-powered perovskite-based photodetector ITO/ZnO(70nm)/CdS(150nm)/CsPbBr3(200nm)/Au, ratio of 106 with a responsivity of 86 mA/W and a specific detectivity of 6.2×1011 Jones was obtained at zero bias under 85 μW/cm2 405 nm illumination, and its rise/decay time at zero bias is to the strong built-in potential and the internal driving electric-field, an ultra-high On/Off current 0.3/0.25 s. Therefore, the enhanced device performance strongly suggest the great potential of such the interfacial charge carriers’ recombination and the charge transport resistance, is presented. Due a kind of trilayer heterojunction devices for high-performance perovskite photodetectors.
关键词： On/Off current ratio,CdS nanorods (NRs) layer,trilayer heterojunction,specific detectivity,gradient energy alignment,Self-powered photodetector,high-performance
更新于2025-09-19 17:13:59
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[IEEE ESSDERC 2019 - 49th European Solid-State Device Research Conference (ESSDERC) - Cracow, Poland (2019.9.23-2019.9.26)] ESSDERC 2019 - 49th European Solid-State Device Research Conference (ESSDERC) - Suspended Antenna-Coupled Nanothermocouple Array for Long-Wave Infrared Detection
摘要： Heat-assisted magnetic recording (HAMR) allows for data writing in hard disks beyond 1 Tb/in2 areal density, by temporarily heating the area of a single bit to its Curie temperature. The metallic optical antenna or near-field transducer (NFT), used to apply the nanoscale heating to the media, may self-heat by several hundreds of degrees. With the NFT reaching such extreme temperatures, demonstrations of HAMR technology experience write-head lifetimes that are orders of magnitude less than that required for a commercial product. Hence, heating of the NFT is of upmost importance. In this paper, we first derive fundamental limits on the temperature ratio NFT/Media to drive NFT design choices for low-temperature operation. Next, we employ inverse electromagnetic design software, which solves for unexpected geometries of the NFT and waveguide. We present computationally generated designs for the waveguide feeding the NFT that offer a 50% reduction in NFT self-heating (～220 °C) compared with typical industry designs.
关键词： optical antenna,Adjoint method,computational electromagnetics,heat-assisted magnetic recording,near-field transducer (NFT),management,thermal,nanophotonics,plasmonics,gradient methods,inverse problem,optimization,hard disks
更新于2025-09-19 17:13:59
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A Non-Isolated Buck-Boost DC-DC Converter with Continuous Input Current for Photovoltaic Applications
摘要： High-power grinding mills are used in the cement and mining industries to crush clinker or copper ore and grind these materials to fine powder. The multi-megawatt speed-controlled mill drives operate at a very low angular speed. Synchronous motors with a high number of pole pairs are used as the prime movers. They are traditionally fed by load-commutated thyristorized cycloconverters. These are prone to failure modes that can lead to excessive torque pulsations and high overcurrents. The huge stator, which was built as a separate ring-shaped structure around the tubular mill, may then get mechanically displaced, and the operation of the plant is interrupted. A novel and reliable direct drive uses a voltage source inverter that operates at the unity power factor for increased efficiency. Synchronous optimal pulsewidth modulation ensures a low harmonic current distortion and reduced switching losses at a very low switching frequency. The optimization of the pulse patterns takes the anisotropic magnetic properties of a separately excited synchronous motor into account. The implementation in a 23-MW semiautonomous grinding mill installed in a Zambian copper mine is intended.
关键词： Alternators,pulse width modulation inverters,gradient methods,ball milling,software algorithms,variable speed drives,Fourier transform
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Hydrogel-Mediated Semiconductor Bonding for Photovoltaic Applications
摘要： The application of fractional calculus to signal processing and adaptive learning is an emerging area of research. A novel fractional adaptive learning approach that utilizes fractional calculus is presented in this paper. In particular, a fractional steepest descent approach is proposed. A fractional quadratic energy norm is studied, and the stability and convergence of our proposed method are analyzed in detail. The fractional steepest descent approach is implemented numerically and its stability is analyzed experimentally.
关键词： Fractional calculus,fractional extreme point,fractional steepest descent gradient,fractional energy norm,fractional differential
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - 1,55 mkm fiber laser with electronic controlled mode-locking
摘要： Signal processing in light-microscopy and cell imaging is concerned with reconstructing latent ground truth from imperfect images. This typically requires assuming prior knowledge about the latent ground truth. While this assumption regularizes the problem to an extent where it can be solved, it also biases the result toward the expected. It thus often remains unclear what prior to use for a given practical problem. We argue here that the gradient distribution of natural-scene images may provide a versatile and well-founded prior for light-microscopy images that does not impose assumptions about the geometry of the ground-truth signal, but only about its gradient spectrum. We provide motivation for this choice from different points of view, and we illustrate the resulting regularizer for use on light-microscopy images. We provide a simple parametric model for the resulting prior, leading to ef?ciently solvable variational problems. We demonstrate the use of these models and solvers in a variety of common image-processing tasks, including contrast enhancement, noise-level estimation, denoising, blind deconvolution, and dehazing. We conclude by discussing the limitations and possible interpretations of the prior.
关键词： variational method,naturalization,gradient distribution,dehazing,parametric prior,noise-level estimation,denoising,Deconvolution
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - A Novel Coding Phase Gradient Metasurface for Wideband RCS Reduction
摘要： In this letter, a new design of metasurface based on coding phase gradient metasurface for wideband radar cross section (RCS) reduction is proposed. The unit cell of the metasurface is composed of a Jerusalem structure and a central circular ring. In order to reduce the burden of the computation time and to optimize design procedure, we use the genetic algorithm and nonlinear fitting method to determine the unit cell geometer. By changing and selecting the parameter of each unit, it is found that the reflection phase of the unit can achieve a stable distribution of phase gradient of the cell among the frequency range of 7.5–26 GHz. In our design, both the random coding sequences and gradient phases in the coding elements are combined to manipulate the EM waves. Four kinds of super-cells with different gradient directions are obtained according to the generalized Snell’s Law, serving as the coding element. A coding metasurface composed of 6 × 6 supercells with random arrangement is designed to improve its RCS reduction. By coding four types of linear-phase gradients in a random pattern, reflected wave can be uniformly diffused. Moreover, the manipulation of waves will be more flexible compared with other designs. The simulated results show that a 10 dB RCS reduction is realized over broadband ranging from 7.5 to 26 GHz.
关键词： nonlinear fitting,coding phase gradient,metasurface,genetic algorithm,RCS reduction
更新于2025-09-19 17:13:59
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Building safety monitoring based on extreme gradient boosting in distributed optical fiber sensing
摘要： Aiming at the problem of the safety monitoring of the surrounding environment of the glass window on the building, a scheme of distributed optical fiber acoustic sensors based on the phase sensitive time-domain reflection is proposed. Firstly, Wigner bispectrum is used to analyze the time–frequency energy distribution of vibration signal, then the axially integrated bispectrum algorithm is used to extract the time–frequency characteristic components, and the method of sub-band division is used to avoid information loss and decrease the cost of computing. The eigenvectors of different vibration events are recognized by extreme gradient boosting tree algorithm. Based on the diversity of acoustic signal types in the environment, there are eight kinds of events including wind blowing, knocking, window opening, watering, hammering, dog barking, aircraft sound and no disturbance to be selected for vibration experiments. The experimental results show that the scheme can get better recognition effect, and the average recognition rate of eight kinds of events reaches 93.3%.
关键词： Building safety monitoring,Distributed acoustic sensor,Wigner bispectrum,Gradient boosting tree
更新于2025-09-19 17:13:59
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Investigating the Dynamics of Intense Pulses Propagating in a Photon Crystal Optical Fiber with a Group Velocity Dispersion Gradient
摘要： The dynamics of soliton-like pulses propagating in a fiber with a group velocity dispersion gradient is studied analytically in the tunnel ionization mode and with forced Raman self-scattering. The these effects are shown to mutually compensate for each other under certain conditions, resulting in signal stabilization.
关键词： group velocity dispersion gradient,signal stabilization,soliton-like pulses,forced Raman self-scattering,tunnel ionization
更新于2025-09-19 17:13:59
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The role of side-branching in microstructure development in laser powder-bed fusion
摘要： In-depth understanding of microstructure development is required to fabricate high quality products by additive manufacturing (for example, 3D printing). Here we report the governing role of side-branching in the microstructure development of alloys by laser powder bed fusion. We show that perturbations on the sides of cells (or dendrites) facilitate crystals to change growth direction by side-branching along orthogonal directions in response to changes in local heat flux. While the continuous epitaxial growth is responsible for slender columnar grains confined to the centreline of melt pools, side-branching frequently happening on the sides of melt pools enables crystals to follow drastic changes in thermal gradient across adjacent melt pools, resulting in substantial broadening of grains. The variation of scan pattern can interrupt the vertical columnar microstructure, but promotes both in-layer and out-of-layer side-branching, in particular resulting in the helical growth of microstructure in a chessboard strategy with 67° rotation between layers.
关键词： microstructure development,additive manufacturing,thermal gradient,side-branching,epitaxial growth,laser powder bed fusion,3D printing
更新于2025-09-19 17:13:59
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Strain Improving the Performance of a Flexible Monolayer MoS <sub/>2</sub> Photodetector
摘要： Electromagnetic wave absorbing foamed ceramics (FCs) with high closed porosity and gradient SiC distribution were prepared from the powder blend containing quartz, talc, CaCO3, Si3N4 and SiC by sintering at 1200 °C for 1 h in air. The retention in the temperature holding process of the continuous and gradual SiC distribution arising from the inward oxidation of SiC in the temperature rising process is the formation mechanism of the gradient SiC distribution in FCs. As to the FC prepared from the powder blend with 3 wt% of SiC, it shows the best comprehensive performance with low bulk density of 0.48 g/cm3 and relatively high compressive strength of 9.6 MPa, good thermal insulation performance for its high total porosity of 82%, good water resistance performance for its high closed porosity of 80%, and excellent electromagnetic wave absorption performance for its low mean re?ectivity of ?11.9 dB in the frequency range of 8.0–18.0 GHz and especially low minimum re?ectivity of ?14.2 dB at 12.7 GHz. More importantly, it is also an excellent high temperature electromagnetic wave absorbing material for its little increased mean re?ectivity of ?11.3 dB after heat treating at 1000 °C for 20 h in air.
关键词： Electromagnetic wave re?ectivity,High closed porosity,Electromagnetic wave absorption performance,Foamed ceramics,Gradient distribution
更新于2025-09-19 17:13:59