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- 2018
- arbitrary coupling coefficients
- Dielectric resonator
- filtering
- coupler
- filtering balun
- dual-band
- dual-mode dielectric resonator (DR)
- Electronic Science and Technology
- Nantong University
- Sun Yat-Sen University
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Numerical Investigation on the Transient Evolution Mechanisms of Nonlinear Phenomena in a Helium Dielectric Barrier Discharge at Atmospheric Pressure
摘要： In this paper, the evolution and transition mechanisms of typical nonlinear phenomena in an atmospheric pressure helium dielectric barrier discharge (DBD) are investigated from the perspective of transient evolution properties through fluid modeling. By gradually up-regulating the interelectrode gap width, the discharge (steady state) evolves from symmetric single-period (SP1), through asymmetric single-period (AP1), into Period-2 (P2) state. Similar evolution trace can also be obtained when increasing the driving frequency. Right after the initial breakdown, the discharge goes through several transient periods featuring unstable asymmetric current pulses before the establishment of steady-state discharge. As the bifurcation parameter increases in excess of the critical value, the discrepancy between the seed electron level of positive and negative discharges accumulates over the transient periods, switching the discharge into AP1 state. After then, a further elevation in the gas gap width (or driving frequency) leads to the generation of a “moderate intensity” positive pulse. With the “moderate intensity” positive pulse and a stronger positive pulse emerging alternatively in the temporal waveform sequence, the discharge evolves into P2 state. Finally, based on the transient evolution mechanisms, a preliminary state-controlling method regarding the use of a first-peak-leveled applied voltage is proposed, which may shed light on the modification of nonlinear states in some practical DBD application scenarios.
关键词： Dielectric barrier discharge (DBD),nonlinear states,mode transition,transient evolution,state-controlling method
更新于2025-09-04 15:30:14
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Fabrication of FP-cavity-based monolithic full-color filter arrays using a template-confined micro-reflow process
摘要： Fabry-Perot (FP) resonators are of great interest for various applications due to their high stability, environmental friendliness and chemical inertia. However, it is still technically challenging to obtain compact monolithic MDM-based color filter array (CFA) because of the difficulty in achieving microscale-pixelated stepwise dielectric films with designed thickness. In this work, we proposed a template-confined thermal reflow approach to fabricate monolithic CFA based on silver-polymethyl methacrylate-silver (Ag-PMMA-Ag) sandwich configuration. Via template-confined thermal reflow of periodic PMMA nanogratings with different filling density, the thickness of PMMA dielectric layer in each pixel can be independently controlled, enabling the spectral tunability across the whole visible light region with high transmission efficiency and narrow linewidth. Compared to conventional multiple deposition technique, the approach we proposed is able to control the thickness of dielectric film via a single exposure step and can be potentially applied in high-throughput production by combining nanoimprint lithography.
关键词： micro-reflow,monolithic stepwise dielectric layer,PMMA,color filter array,Fabry-Perot resonator
更新于2025-09-04 15:30:14
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ANALYSIS OF SCATTERING FROM COMPOSITE CONDUCTOR AND DIELECTRIC OBJECTS USING SINGLE INTEGRAL EQUATION METHOD AND MLFMA BASED ON JMCFIE
摘要： A highly e?cient hybrid method of single integral equation (SIE) and electric/magnetic current combined ?eld integral equation (JMCFIE) is presented, named as SJMCFIE, for analysing scattering from composite conductor and dielectric objects, in which, SIE can reduce one half unknowns in dielectric region. The resultant matrix equation of SJMCFIE can be represented in the iteration form, which makes the computation complexity reduced further, and coupling mechanism of composite model becomes more explicit. For accelerating matrix-vector multiplications (MVMs), Multilevel Fast Multipole Algorithm (MLFMA) is employed to combine SJMCFIE to formulate SJMCFIE-MLFMA at last, which is the extension of SIE-MLFMA in the proposed reference. Finally, some examples verify the new hybrid method on accuracy, memory storage, computation e?ciency compared to SIE-MLFMA and JMCFIE-MLFMA. Besides, SJMCFIE-MLFMA can also be used to analyse the complete coated model’s scattering.
关键词： composite conductor and dielectric objects,Multilevel Fast Multipole Algorithm,electric/magnetic current combined ?eld integral equation,single integral equation,scattering
更新于2025-09-04 15:30:14
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[Smart Innovation, Systems and Technologies] Information and Communication Technology for Intelligent Systems Volume 107 (Proceedings of ICTIS 2018, Volume 2) || Performance Booster Electrical Drain SiGe Nanowire TFET (EDD-SiGe-NW-TFET) with DC Analysis and Optimization
摘要： In this paper, new concept for TFET nanowire is proposed to eliminate the issues aroused in MOSFET due to continuous scaling the device dimensions. Proposed device uses the concept of electrically doping as well as physically doping. Other than that low band gap material, silicon germanium (SiGe), is used at source region and high k dielectric is used at source–channel interface to improve the performance of the proposed structure. Simulation is done using 3D TCAD ATLAS simulator, and result validates that the proposed device is suitable for low power application. Furthermore, simulation is done for the different diameters and channel lengths for optimization.
关键词： Electrical drain,Nanowire TFET,Low band gap,Hetero dielectric
更新于2025-09-04 15:30:14
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Effect of doping Gd2O3 on dielectric and piezoelectric properties of BaZr0.1Ti0.9O3 ceramics by sol–gel method
摘要： The effects of sintering temperature and doping amount of gadolinium ions on the microstructures and electrical properties of sol gel derived Ba (Zr0.1Ti0.9) O3 + xGd ceramics were investigated in this manuscript. XRD analysis showed that the main crystalline phase of BZT-xGd ceramic samples exhibit a perovskite structure without significantly change. The sample sintered at 1350 °C and doped with gadolinium ions of 0.5 mol% has uniform grain size and compact morphology. And the sample(1350 °C—0.5 mol%) also has a high piezoelectric charge coefficient of 131.33 pC/N, large plane electromechanical coupling coefficient of 0.22, high dielectric constant of 10504, and small dielectric loss of 0.01. The correlation of dielectric and piezoelectric properties of BZT-xGd ceramics with doping amount of Gd3+ ion has been explained by the lattice theory.
关键词： BZT-xGd ceramics,dielectric properties,sol–gel method,gadolinium doping,piezoelectric properties
更新于2025-09-04 15:30:14
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Illusion Optics: Disguising with Ordinary Dielectric Materials
摘要： Illusion devices are usually designed using transformation optics. Here, a new method is proposed to achieve optical illusions without external devices by elaborately manipulating the scattering potential of an object. In contrast to the conventional transformation optics method, which completely replaces one object by the image of another object using complementary\restoring media and a superlens, the method described here is more of a cosmetic operation for an object, which modifies the scattering pattern of the object to mimic another object by exchanging their scattering potentials in two symmetrical areas in the wave vector domain. Only positive isotropic non-magnetic materials are introduced in the present method, which is impossible using the conventional method because superlenses require negative-index materials. Both numerical simulations and experimental demonstrations are used to verify the performance of the illusion devices of this method.
关键词： scattering potential,wave vector domains,illusion optics,isotropic dielectric materials
更新于2025-09-04 15:30:14
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Multi-electron reduction of Wells–Dawson polyoxometalate films onto metallic, semiconducting and dielectric substrates
摘要： The investigation of conditions allowing multi-electron reduction and reoxidation of polyoxometalate (POM) films onto solid substrates is considered an issue of critical importance for their successful incorporation in electronic devices, different types of sensors and catalytic systems. In the present paper, the rich multi-electron redox chemistry of films of Wells–Dawson ammonium salts, namely (NH4)6P2Mo18O62 and (NH4)6P2W18O62, on top of metallic (Al), semiconducting (ITO) and dielectric (SiO2) substrates under ambient conditions is investigated. The respective Keggin heteropolyacids, H3PMo12O40 and H3PW12O40, are also investigated for comparison. On Al substrates, the Wells–Dawson ammonium salts are found to be significantly more reduced (4–6e?) compared to the respective Keggin heteropolyacids (≤2e?), in accordance with their deeper lying lowest unoccupied molecular orbital (LUMO) level. Subsequent thermal treatment in air results in reoxidation of the initially highly reduced POM films. Similar behavior is found on ITO substrates, but in initially less reduced (2–4e?) Wells–Dawson POM films. On the other hand, on SiO2 substrates, the thermal reduction of (NH4)6P2Mo18O62 film is observed and attributed to the thermal oxidation of ammonium counterions by [P2Mo18O62]6? anions. Overall, the multi-electron reduction of Wells–Dawson ammonium salts onto metallic and semiconducting substrates (Al, ITO) is determined by the relative position of the LUMO level of POMs in relation to the Fermi level of the substrate (i.e. substrate work function) and affected in a synergistic way by the presence of ammonium counterions. In contrast, on dielectric substrates (SiO2) the reduction of Wells–Dawson POMs ((NH4)6P2Mo18O62) is attributed only to the oxidation of ammonium counterions.
关键词： Polyoxometalates,Semiconducting substrates,Ammonium counterions,Wells–Dawson ammonium salts,Redox chemistry,Keggin heteropolyacids,Metallic substrates,Dielectric substrates,Thermal treatment,Multi-electron reduction
更新于2025-09-04 15:30:14
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Square superlattice pattern with discharge holes due to direction-selective surface discharges in dielectric barrier discharge
摘要： We report a square superlattice pattern with discharge holes due to direction-selective surface discharges (SDs) in a dielectric barrier discharge system for the ?rst time. The instantaneous images with an exposure time of 10 ls (half cycle of voltage) taken using a high-speed video camera show that the directions of surface discharges (SDs) of the small spots are selective, which are different from the directions of SDs of the large spots diffused in all directions. In each positive half cycle of voltage, the graphs captured using an intensi?ed charge-coupled device show that the large spot discharges after the small spots and locates at the center of the square formed by the SDs induced by small spots but not their cross point. In each negative half cycle of voltage, the large spots discharge before the small spot and press the SD of the small spot to stretch along the midperpendicular of two adjacent large spots. In a word, the direction-selective surface discharges play a crucial role for the formation of the pattern with the discharge holes in the dielectric barrier discharge system.
关键词： direction-selective surface discharges,square superlattice pattern,dielectric barrier discharge,discharge holes
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Kuah (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Simulating the Annual Energy Yield of a Rotationally Asymmetrical Optical Concentrator
摘要： This paper simulates the annual energy yield of a concentrator called the rotationally asymmetrical dielectric totally internally reflective concentrator (RADTIRC). One specific design of the RADTIRC is assumed to be installed in Berlin/Brandenburg, Germany. Simulation and experimental work have been carried out to determine the optical concentration gain under direct and diffuse radiations. Based on the analysis, it was found that the yearly energy yield was increased by a factor of 2.29 when the RADTIRC-PV module was used when compared with the non-concentrating PV module.
关键词： annual output,Berlin,solar photovoltaic,rotationally asymmetrical dielectric totally internally reflecting concentrator,building integrated photovoltaic systems
更新于2025-09-04 15:30:14
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Fast gas heating of nanosecond pulsed surface dielectric barrier discharge: Spatial distribution and fractional contribution from kinetics
摘要： The effect of heat release in reaction with charged and electronically excited species, or so-called fast gas heating (FGH) in nanosecond surface dielectric barrier discharge (nSDBD) in atmospheric pressure air is studied. 2D numerical simulations based on PASSKEy code (PArallel Streamer Solver with KinEtics code) are conducted. The code is based on the direct coupling of a self-consistent fluid model with detailed kinetics, an efficient photo-ionization model and Euler equations. The choice of local field approximation for nSDBD modeling with simplified kinetics is discussed. The reduced electric field and the electron density are examined at both polarities for the identical high-voltage pulses 24 kV in amplitude on the high voltage electrode and 20 ns FWHM. The distribution of the fast gas heating energy and the resulting gas temperature field are studied and compared with existing references. The input of different reactions to appearing hydrodynamic perturbations is analyzed.
关键词： nanosecond surface dielectric barrier discharge,plasma modeling,fast gas heating,nSDBD
更新于2025-09-04 15:30:14