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- 2019
- Distributed optical fiber sensing
- Optical frequency domain reflection
- Polynomial regression algorithm
- Nonlinear tuning compensation
- Optoelectronic Information Science and Engineering
- Hebei University of Technology
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Broadband high-efficiency cross-polarization conversion and multi-functional wavefront manipulation based on chiral structure metasurface for terahertz wave
摘要： In this paper, a broadband and high-efficient tri-layered chiral structure metasurface (CSM) for linear polarization conversion and multi-functional wavefront manipulation was proposed and investigated numerically in terahertz region. The unit-cell of the proposed CSM consist of two orthogonal metal wires sandwiched with square split-ring resonator (SRR) structure, which can manipulate the polarization and wavefront of the transmitted wave simultaneously. Based on the Fabry-Perot-like cavity-enhanced effect of proposed CSM, broadband and high-efficiency cross-polarization conversion can be achieved. Numerical simulation results indicate that the cross-polarization transmission coefficient is higher than 0.9 from 0.4 THz to 1.0 THz, with a fractional bandwidth of 85.7%. The proposed CSM can achieve complete 2π phase coverage by adjusting the geometric parameters of the unit-cell structure. As a proof of multi-functional wavefront manipulation, anomalous refraction with a wide angle, two kinds of focusing metalenses and vortex beam generation are investigated to verify the multi-functional wavefront manipulation performance of the proposed CSM. Our work provides an effective method of enhancing the performance of transmission-type metasurface and the proposed devices show endless potential in wavefront control and communication applications in terahertz region.
关键词： chiral structure metasurface,linear polarization conversion,terahertz,wavefront manipulation
更新于2025-09-23 15:19:57
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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) - Efficient light management in narrow-bandgap perovskite solar cells
摘要： We develop a theory of algebraic operations over linear and context-free grammars that makes it possible to combine simple “atomic” grammars operating on single sequences into complex, multi-dimensional grammars. We demonstrate the utility of this framework by constructing the search spaces of complex alignment problems on multiple input sequences explicitly as algebraic expressions of very simple one-dimensional grammars. In particular, we provide a fully worked frameshift-aware, semiglobal DNA-protein alignment algorithm whose grammar is composed of products of small, atomic grammars. The compiler accompanying our theory makes it easy to experiment with the combination of multiple grammars and different operations. Composite grammars can be written out in LATEX for documentation and as a guide to implementation of dynamic programming algorithms. An embedding in Haskell as a domain-speci?c language makes the theory directly accessible to writing and using grammar products without the detour of an external compiler. Software and supplemental ?les available here: http://www.bioinf.uni-leipzig.de/Software/gramprod/
关键词： multiple alignment,context free grammar,product structure,linear grammar,Haskell
更新于2025-09-23 15:19:57
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The dispersion behaviors of the tripod-type four-level cylindrical quantum dot under phenomenon of electromagnetically induced transparency
摘要： In this paper, linear and 3rd-order nonlinear group velocities of the probe laser field are investigated in a tripod-type four-level cylindrical quantum dot (TTFLCQD) with parabolic potential in electromagnetically induced transparency. The control lasers at z-polarization are applied to the system and the results are investigated. Also, linear and 3rd-order nonlinear group velocities in z-polarization are compared. The effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed. The linear and 3rd-order nonlinear group velocities are compared at z-polarization. Furthermore, the effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed. The linear and 3rd-order nonlinear group velocities are compared at z-polarization. Furthermore, the effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed.
关键词： Electromagnetically induced transparency,Tripod-type four-level cylindrical quantum dot,Nonlinear group velocity,Linear group velocity,Slow light
更新于2025-09-23 15:19:57
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - VIS-NIR GeSi Photodetector with Voltage Tunable Spectral Response
摘要： An innovative double-sided tubular linear induction motor is presented, and its optimal design in terms of thrust force is discussed. A dedicated semi-analytical model of the device is developed allowing for fast and accurate evaluation of all the electromechanic quantities in the device, including the thrust force, back-electromotive force, distribution of the induced current, and average magnetic flux density in the teeth. This provides a basis for the design optimization, which has been performed by a novel evolutionary algorithm based on the self-organizing maps. Using the semi-analytical formulation, the characterization of the machine is greatly facilitated, thus allowing a fast evaluation of the cost function and design constraints. Finally, the obtained optimal design is validated by comparison with finite elements method analysis.
关键词： linear motors,Electromagnetic analysis,induction motors,induction accelerators,optimization methods
更新于2025-09-23 15:19:57
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Magnetic Layer-by-Layer Assembly: From Linear Plasmonic Polymers to Oligomers
摘要： One-dimensional (1D) nanostructures with controllable aspect ratios are essential for a wide range of applications. An approach for magnetic superparticle (SP) assembly over large areas (55 mm × 25 mm) is introduced via co-assistance of electrostatic and magnetic fields, so-called magnetic layer-by-layer (MLBL) assembly, on an arbitrary hydrophilic substrate within minutes. The SP structures (diameter (d.) = 120-350 nm) of Fe3O4 or Ag@Fe3O4 composites composed of hundreds of magnetite nanocrystals (d. 10–20 nm) are used as colloidal monomers to fabricate arrays of high-aspect-ratio (up to 102) linear nanochains, viz. colloidal polymers, where thermal disturbances were minimized. The arrays of colloidal polymers exhibit strong optical polarization effects owing to their geometrical anisotropy, which can be used as a simple optical filter. Furthermore, by using the binary colloidal mixture of different magnetic colloids including different-sized Fe3O4 and magnetoplasmonic Ag@Fe3O4, low-aspect-ratio (2~15) colloidal chains, viz. magnetic/plasmonic oligomers, with tunable lengths were fabricated, affording a facile but effective approach to modulate the optical properties of the chains. The scalable fabrication of well-aligned, linear colloidal polymers and oligomers opens up appealing opportunities for the development of sensors, sub-wavelength waveguides, optical tweezers, and enhanced solar harvesting devices.
关键词： nanochain array,layer-by-layer,linear nanochain,colloidal oligomer,plasmonic oligomer,magnetic field induced assembly
更新于2025-09-23 15:19:57
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Impact of fourth order dispersion on modulational instabilities in asymmetrical three-core optical fiber
摘要： In this paper we investigate the impact of linear coupling coefficient and coupling coefficient dispersion on modulational instability (MI) in the presence of fourth order dispersion (FOD) in an asymmetric three core optical fiber under normal and anomalous dispersion regime. In addition, we also considered the impact of symmetric and asymmetric power ratio on MI characteristics. It is found that there is significant influence by linear coupling coefficient and frequencies is highly controlled by FOD, but the amplitude of MI gain found to be reduced with increasing FOD under each dispersion regimes. In case of CCD, the impact of FOD found to be quite insensitive and found no MI gain in the absence of CCD under symmetric power ratio under coupling coefficient dispersion (CCD) on MI under different dispersion regimes. In anomalous dispersion regime, at β4 < 0 the generation of smaller MI secondary side bands were observed at higher frequencies while at normal dispersion the effect of FOD leads to breaking of MI gain at different values of coupling coefficient. Though the appearance of the MI gain at different frequencies is highly controlled by FOD, but the amplitude of MI gain found to be reduced with increasing FOD under each dispersion regimes.
关键词： modulational instability,asymmetrical three-core optical fiber,fourth order dispersion,linear coupling coefficient,coupling coefficient dispersion
更新于2025-09-23 15:19:57
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A high throughput, linear molecular beam epitaxy system for reduced cost manufacturing of GaAs photovoltaic cells: will GaAs ever be inexpensive enough?
摘要： Solar cells based on GaAs and related compounds provide the highest reported efficiency single junction and multijunction solar cells. However, the cost of the cells is prohibitive when compared with Si and other thin film solar technologies. One significant differentiator is the high cost required to grow the epitaxial layers. Here, we propose a molecular beam epitaxy (MBE) system design that has the potential to increase the epitaxial layer growth throughput, thereby significantly reducing production costs. A rack-and-pinion based linear transfer system sequentially transfers multiple substrate platens between interconnected growth positions within the chamber, thereby synchronously growing layers on many wafers in the desired order and at the required thicknesses. The proposed linear MBE platform is the basis for a realistic analysis of GaAs single junction photovoltaic cell production cost. Our model projects a nearly 55% cost reduction in epitaxial growth via linear MBE when compared to conventional MBE, and a 85% reduction when further process optimization is assumed and combined with non-destructive lift off. Even when considering all of these factors in an optimistic light, the cost of epitaxial unconcentrated GaAs solar cells using any existing growth process is unlikely to drop below $3 per Wp in the foreseeable future.
关键词： photovoltaic cells,GaAs,molecular beam epitaxy,linear MBE,cost reduction
更新于2025-09-23 15:19:57
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[IEEE 2019 11th Electrical Engineering Faculty Conference (BulEF) - Varna, Bulgaria (2019.9.11-2019.9.14)] 2019 11th Electrical Engineering Faculty Conference (BulEF) - Spectral luminance modeling of a LED luminaire, made by the Tunable White techology
摘要： We develop a theory of algebraic operations over linear and context-free grammars that makes it possible to combine simple “atomic” grammars operating on single sequences into complex, multi-dimensional grammars. We demonstrate the utility of this framework by constructing the search spaces of complex alignment problems on multiple input sequences explicitly as algebraic expressions of very simple one-dimensional grammars. In particular, we provide a fully worked frameshift-aware, semiglobal DNA-protein alignment algorithm whose grammar is composed of products of small, atomic grammars. The compiler accompanying our theory makes it easy to experiment with the combination of multiple grammars and different operations. Composite grammars can be written out in LATEX for documentation and as a guide to implementation of dynamic programming algorithms. An embedding in Haskell as a domain-speci?c language makes the theory directly accessible to writing and using grammar products without the detour of an external compiler. Software and supplemental ?les available here: http://www.bioinf.uni-leipzig.de/Software/gramprod/
关键词： Haskell,context free grammar,multiple alignment,product structure,linear grammar
更新于2025-09-23 15:19:57
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[IEEE IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - Yokohama, Japan (2019.7.28-2019.8.2)] IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium - Results of Vibrational and Thermal Test for MOLI Laser Transmitter
摘要： Currently, self-healing is one of the most important functions in the smart grid. Meanwhile, fault detection, isolation, and restoration of feeder automation systems dominate the self-healing function in power distribution systems. The steps of the aforementioned function depend on the fault ?ag status of the feeder terminal unit. The conditions for setting this ?ag are judged by the feeder terminal unit overcurrent detecting curve. This paper found an ef?cient approach to calculate this curve via a half-interval method. Versatile application software with the curve plotting capability was also developed and deployed on the web server of the information-management department of Taiwan Power Company and is running successfully.
关键词： piecewise linear approximation,power distribution protection,IEEE standards,fault currents,Computer aided analysis
更新于2025-09-23 15:19:57
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An Experimental Study on Mixed-dimensional 1D-2D van der Waals Single-Walled Carbon Nanotube-WSe2 Hetero-Junction
摘要： Parking in major cities, particularly with dense traffic, directly effects the traffic flow and people’s life. In this paper, we introduce a new smart parking system that is based on intelligent resource allocation, reservation, and pricing. The proposed system solves the current parking problems by offering guaranteed parking reservations with the lowest possible cost and searching time for drivers and the highest revenue and resource utilization for parking managers. New fair pricing policies are also proposed that can be implemented in practice. The new system is based on mathematical modeling using mixed-integer linear programming (MILP) with the objective of minimizing the total monetary cost for the drivers and maximizing the utilization of parking resources.
关键词： dynamic resource allocation,smart car parking,mixed integer linear programming (MILP),reservation,Dynamic pricing
更新于2025-09-23 15:19:57