- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Topological and Geometrical Effects in the Bulk Hall Response of Driven-Dissipative Photonic Lattices
摘要： In the advanced manufacturing industry, planar switched reluctance motors (PSRMs) have proved to be a promising candidate due to their advantages of high precision, low cost, low heat loss, and ease of manufacture. However, their inverse force function, which provides vital phase current command for precise motion, is highly nonlinear and hard to be accurately modeled. This paper proposes a novel inverse force function using sparse least squares support vector machines (LS-SVMs) to achieve nonlinear modeling for precise motion of a PSRM. The required training and testing sets of sparse LS-SVMs are ?rst obtained from experimental measurement. A sparse LS-SVMs regression is further developed using training set to accurately model the inverse force function. Accordingly, the function is tested via the testing set to assess its feasibility. Finally, the proposed approach is applied to the PSRM system with dSPACE controller for trajectory tracking, and its effectiveness and superior performance are veri?ed through experimental results.
关键词： Inverse force function,least squares support vector machines (LS-SVMs),phase current estimation,nonlinear modeling,planar switched reluctance motors (PSRMs)
更新于2025-09-19 17:13:59
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Coherence Properties of Multi-Section Semiconductor Frequency Swept Lasers
摘要： A novel planar ultrathin electronically steerable parasitic array radiator (ESPAR) is presented in this paper. Through theoretical analysis of the electric fields of orthogonally crossed dipoles in phase quadrature, it is found that the crossed dipoles radiate linearly polarized wave with a rotational electric field in the azimuth plane. This characteristic is then utilized to design a planar crossed dipole ESPAR, termed as “CD-ESPAR.” Furthermore, a simple but effective impedance matching method is also proposed and analyzed. To verify these concepts, a prototype with compact size and very low profile (0.42 λ0 × 0.42 λ0 × 0.006 λ0) resonating at 2.3 GHz is designed, fabricated, and measured. The measured results indicate that the proposed antenna achieves more than 17.8% impedance bandwidth and can produce four directional beams, covering the whole azimuth plane. Owing to its planar ultrathin structure, compact size, electronically beam-switching ability, low power, and low cost characteristics, it is promising for applications in wireless communications.
关键词： crossed dipoles,planar antenna,smart antenna,Beam-switching,electronically steerable parasitic array radiator (ESAPR)
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Measured dc Arc-flash Risk in a Photovoltaic System
摘要： In this paper, the energy recovery in microstrip passive circuits from the power losses into heat is studied. For this purpose, a thermoelectric generator (TEG) based on the Seebeck effect principle is used, which converts part of the power dissipated into heat to dc electrical power. A solution integrating the TEG with the microstrip circuit is proposed, and design guidelines in order to optimize the recovered power keeping a good isolation between the RF signal and the TEG system are provided. As will be shown, under moderate applied signal powers of just 1–5 W, the levels of recovered power in microstrip passive circuits can be notable. As a demonstrator circuit, an integration device formed by an embedded microstrip bandpass filter for WiMAX applications and a TEG is designed, fabricated, and characterized (thermal and electrically). Different scenarios are considered, depending on frequency and thermal loads. For an applied in-band CW input signal power of 2 W at 3.48 GHz, a recovered power of around 250 μW has been continuously supplied to the electrical load. Several aspects, such as efficiency and future improvements, are also discussed.
关键词： power applications,Average power handling capability (APHC),microwave devices,planar circuits,energy recovery,electro-thermal analysis,energy harvesting
更新于2025-09-19 17:13:59
-
Silicon Nitride and Carbonitride Films for Waveguide Structures Based on Strained Silicon
摘要： Waveguide microstructures based on strained silicon with the use of silicon carbonitride and silicon nitride ?lms as cladding layers are created. A plasma-enhanced chemical vapor deposition technique is developed, which allows obtaining high values of intrinsic mechanical stresses in ?lms (about 700 MPa). The strained waveguide structures are characterized by micro-Raman spectroscopy during a scanning procedure. It is demonstrated that deposition of silicon carbonitride and silicon nitride ?lms induces compressive stresses in the silicon waveguide, which is proved by the shift of the maximum of the main peak of scattering on LO-phonons of silicon toward higher wave numbers. The compressive stresses in the silicon waveguide clad with silicon nitride and carbonitride layers are estimated as 350 and 250 MPa, respectively, which is su?cient for the emergence of nonlinear optical properties of silicon (Pockels e?ect).
关键词： Raman spectroscopy,strained silicon,silicon carbonitride,silicon nitride,planar optical waveguides
更新于2025-09-19 17:13:59
-
Solvation Controlled Excited-State Planarization in a Pusha??Pull Pyrene Dye
摘要： The excited state deactivation pathway of the push–pull pyrene derivative (EPP), a molecule emitting bright red fluorescence, has been studied in several solvents using quantum chemical calculations, femtosecond time-resolved fluorescence up-conversion spectroscopy and femtosecond transient absorption spectra (fs-TA). From the steady-state spectra, EPP has shown a strong negatively solvatochromic behavior of the absorption spectra and a non-solvatochromic emission spectra, revealing the decreased dipole moment upon excitation. Femtosecond up-conversion measurements have shown interesting rise-decay kinetics at red emission side and fs-TA spectra also feature the SE (Stimulated emission) formed and new ESA (Excited State Absorption) developed in all investigated solvents. The careful analysis of the data gathered from fluorescence up-conversion and fs-TA spectra, supported by DFT quantum chemical calculations and temperature-dependent fluorescence measurements, unambiguously pointed out the excited state relaxation pathway of EPP is controlled by solvent stabilized planar intramolecular charge transfer (PICT) dynamics. This finding confirms the surrounding solvents as a significant factor that affects the rate of excited state conformation changes.
关键词： solvation controlled,push–pull pyrene derivative,excited state deactivation,planar intramolecular charge transfer,femtosecond spectroscopy
更新于2025-09-19 17:13:59
-
Room-temperature processed ZrO2 interlayer towards efficient planar perovskite solar cells
摘要： The Sn-doped In2O3 transparent conductive (ITO) electrode in planar perovskite solar cells (PSCs) is modified by zirconia (ZrO2) interlayer with low-temperature process. Here the ZrO2 film is prepared by ultraviolet (UV) treatment at room temperature. The effects of the inserted ZrO2 interlayer on the performance of CH3NH3PbI3-xClx-based PSCs have been systemically studied. After optimizing the process, the champion efficiency of PSC with UV-treated ZrO2 interlayer is 19.48%, which is larger than that of the reference PSC (15.56%). The improved performance in the modified devices is primarily ascribed to the reduced trap states and the suppressed carrier recombination at the ITO/SnO2 interface. Our work provides a facile route to boost the photovoltaic performance of PSCs by modifying the surface of transparent conductive electrode at room temperature.
关键词： Photoelectric properties,ITO/SnO2 interface modification,Ultraviolet (UV) treatment,Planar perovskite solar cell,Room-temperature processed ZrO2 interlayer
更新于2025-09-19 17:13:59
-
On the contribution of fullerene to the current of planar heterojunction organic solar cells.
摘要： Recently, significant progress in the field of organic photovoltaic cells was obtained by substituting new electron acceptor molecules to the fullerene, which was attributed to the fact that the fullerene absorption is quite small. Nevertheless, we demonstrate in the present work that, in the case of inverted cells, i.e. when the transparent bottom electrode is used as cathode, the contribution of fullerene to the Jsc short-circuit current of the cells, if not dominant, is not negligible; and that mainly in the short wavelength spectral range. The experimental results are confirmed by an optical simulation. Due to this significant contribution to Jsc, the light transmission of the transparent electrode towards the UV-part of the spectrum is crucial for inverse cell performances. When a transparent conductive electrode based on an alternative dielectric/metal/dielectric structure is substituted to ITO, such as ZnS/Ag/TiO2, the study allows to obtain promising results, although there is a loss of performance due to the decrease of transmission of TiO2 below 400 nm in wavelength.
关键词： Absorption,Optical Modeling,External Quantum Efficiency,Organic solar cells,Planar heterojunction
更新于2025-09-19 17:13:59
-
Infrared subwavelength focusing metasurfaces for harvesting heat from the Eartha??s back radiation
摘要： In this paper, we introduce two different metasurfaces that can achieve subwavelength focusing of the electromagnetic radiation in the infrared range with transmission ef?ciencies reaching 46% and 74.33% in silicon and thus they can be integrated in heat harvesting applications. We made our designs at the wavelength of 10 μm which is the peak of the back radiation of the Earth. In designing our metasurfaces in the infrared range, we used the phase modulation techniques that proved to be useful in the visible domain. The best focusing resolution achieved in our metasurfaces is 0.26λ (super-focusing). In addition to heat harvesting, the two proposed metasurfaces can be useful in other compact applications that require manipulating the mid-infrared radiation on a very small scale. We used copper and silicon in our metasurfaces which are speci?cally suitable for the mid-infrared range besides being CMOS compatible. In this paper, we also explained how heat can be harvested from the introduced metasurfaces using the Seebeck effect.
关键词： plasmonics,subwavelength focusing,planar lens,phase modulation,heat harvesting,metasurface,mid-infrared focusing
更新于2025-09-19 17:13:59
-
Investigation of Dilution Effect on CH4/Air Premixed Turbulent Flame Using OH and CH2O Planar Laser-Induced Fluorescence
摘要： Diluting the combustion mixtures is one of the advanced approaches to reduce the NOx emission of methane/air premixed turbulent ?ame, especially with high diluents to create a distributed reaction zone and mild combustion, which can lower the temperature of reaction zone and reduce the formation of NOx. The e?ect of N2/CO2 dilution on the combustion characteristics of methane/air premixed turbulent ?ame with di?erent dilution ratio and di?erent exit Reynolds number was conducted by OH-PLIF and CH2O-PLIF. Results show that the increase of dilution ratio can sharply reduce the concentration of OH and CH2O, and postpone the burning of fuel. Compared with the ultra-lean combustion, the dilution weakens the combustion more obviously. For di?erent dilution gases, the concentration of OH in the combustion zone varies greatly, while the concentration of CH2O in the unburned zone is less a?ected by di?erent dilution gas. The CO2 dilution has a more signi?cant e?ect on OH concentration than N2 with the given dilution ratio, but a similar e?ect on the concentration of CH2O in the preheat zone of ?ame. However, dilution does not have much in?uence on the ?ame structure with the given turbulent intensity.
关键词： turbulent ?ame,planar laser-induced ?uorescence,OH,premixed,CH2O,dilution
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Monolithic CZTS/Si tandem cells: development of multilayer structures for the intermediate contact
摘要： A novel planar ultrathin electronically steerable parasitic array radiator (ESPAR) is presented in this paper. Through theoretical analysis of the electric ?elds of orthogonally crossed dipoles in phase quadrature, it is found that the crossed dipoles radiate linearly polarized wave with a rotational electric ?eld in the azimuth plane. This characteristic is then utilized to design a planar crossed dipole ESPAR, termed as “CD-ESPAR.” Furthermore, a simple but effective impedance matching method is also proposed and analyzed. To verify these concepts, a prototype with compact size and very low pro?le (0.42 λ0 × 0.42 λ0 × 0.006 λ0) resonating at 2.3 GHz is designed, fabricated, and measured. The measured results indicate that the proposed antenna achieves more than 17.8% impedance bandwidth and can produce four directional beams, covering the whole azimuth plane. Owing to its planar ultrathin structure, compact size, electronically beam-switching ability, low power, and low cost characteristics, it is promising for applications in wireless communications.
关键词： crossed dipoles,planar antenna,smart antenna,Beam-switching,electronically steerable parasitic array radiator (ESAPR)
更新于2025-09-19 17:13:59