- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[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) - Measurement of Electromagnetic Characteristics Materials in a Rectangular Waveguide
摘要： A waveguide method for measuring the relative complex dielectric constant of ?at samples of insulating materials that is invariant to the position of the sample over a waveguide section is discussed. The exclusion of the e?ect of coaxial-waveguide transitions on the measurement results is performed by the LR method. The measured parameters are determined in the frequency range by minimizing the objective function.
关键词： frequency range,LR method,waveguide method,complex dielectric constant,insulating materials
更新于2025-09-19 17:13:59
-
[IEEE 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Aswan City, Egypt (2019.10.23-2019.10.25)] 2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE) - Integrated Single Output Sensor Distributed MPPT for Photovoltaic Systems: A Novel Per-Cell Approach
摘要： The temporal variations (diurnal and annual) in arboreal (εTree) and bare soil (εSoil) dielectric constants and their correlation with precipitation were examined for several trees in Japan. A significant (1 σ (standard deviation) and 2 σ) εTree increase is observed after rainfall at 89.8% and 90.5% probability. However, rainfall does not always induce significant εTree increases. Rainfall of more than 5 mm/day can induce 1 σ εTree increase at a 59.6% probability. In order to examine whether the increase in εTree affects the L-band σ0 variation in a forest, the four-year temporal variation of the L-band backscattering coefficient (σ0) was estimated from observations by the Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar. Observed maximum absolute deviations from the mean over the forest area were 1.0 and 1.2 dB for σ0 HV, respectively, and 4.0 and 3.0 dB over open land. σ0 and σ0 and rainfall correlations show that εTree and σ0 Forest are proportional to precipitation integrated over seven or eight days; εSoil and σ0 Open land are proportional to precipitation integrated over three days. This finding indicates that εTree variations influence σ0 Forest areas. A stronger correlation between σ0 HV and precipitation is observed in several sites with low σ0 HV, where less biomass is expected, and several sites with high σ0 HV, where more biomass is expected. A weaker correlation between σ0 HV and precipitation is observed for several sites with high σ0 HV. These differences may be explained by the different contributions of double bounce scattering and potential transpiration, which is a measure of the ability of the atmosphere to remove water from the surface through the processes of transpiration. The two other results were as follows: 1) The functional relation between aboveground biomass and σ0 showed dependence on precipitation data, this being an effect connected with seasonal changes of the εTree. This experiment reinforces the fact that the dry season is preferable for retrieval of woody biomass from inversion of the functional dependence of SAR backscatter and for avoiding the influence of rainfall. 2) The complex dielectric constant for a tree trunk, which is measured between 0.2 and 6 GHz, indicates that free water is dominant in the measured tree.
关键词： forest,temporal variation,dielectric constant,Biomass,Phased Array type L-band Synthetic Aperture Radar (PALSAR)
更新于2025-09-19 17:13:59
-
Insights from Device Modeling of Perovskite Solar Cells
摘要： In this perspective, we explore the insights into the device physics of perovskite solar cells gained from modeling and simulation of these devices. We discuss a range of factors that influence the modeling of perovskite solar cells, including the role of ions, dielectric constant, density of states, and spatial distribution of recombination losses. By focusing on the effect of non-ideal energetic alignment in perovskite photovoltaic devices, we demonstrate a unique feature in low recombination perovskite materials – the formation of an interfacial, primarily electronic, self-induced dipole that results in a significant increase in the built-in potential and device open-circuit voltage. Finally, we discuss the future directions of device modeling in the field of perovskite photovoltaics, describing some of the outstanding open questions in which device simulations can serve as a particularly powerful tool for future advancements in the field.
关键词： device physics,density of states,simulation,device modeling,recombination losses,dielectric constant,perovskite solar cells,energetic alignment
更新于2025-09-19 17:13:59
-
Da??A Polymer with a Donor Backbone a?? Acceptora??sidea??chain Structure for Organic Solar Cells
摘要： We report the design, synthesis, and properties of a novel type of donor (D)-acceptor (A) polymer, poly(3-(([2,2':5',2''-terthiophen]-3-yl-5,5"-diyl)methylene)-1-(2-octyldodecyl)indolin-2-one) (PTIBT), with a donor backbone and acceptor side chains (Type II D-A polymer) as donor for organic solar cells (OSCs) as opposed to the conventional D-A polymers having both donor and acceptor units on backbone (Type I D-A polymers). PTIBT having a backbone consisting of thiophene donor units and side chains containing indolin-2-one acceptor units was synthesized very conveniently in three steps. This polymer has a high dielectric constant of 7.70, which is beneficial for the exciton diffusion and dissociation in the active blend layer in an OSC. In addition, PTIBT was found to have a low-lying HOMO energy level of -5.41 eV and a wide band gap of 1.80 eV in comparison to its counterpart Type I D-A polymer. In organic thin film transistors (OTFTs), PTIBT showed typical p-type semiconductor performance with hole mobilities of up to 1.81 × 10-2 cm2V-1s-1. When PTIBT and ITIC were used as donor and acceptor to form a blend active layer, the best OSC device showed a JSC of 15.19 mAcm-2, a VOC of 0.66 V, and a fill factor of 0.57, resulting in a power conversion efficiency (PCE) of up to 5.72%.
关键词： dielectric constant,novel D-A polymer donor,polythiophene,organic solar cells,nonfullerene acceptor
更新于2025-09-19 17:13:59
-
Electrons in Solids (Mesoscopics, Photonics, Quantum Computing, Correlations, Topology) || 4. Correlated electrons in complex transition metal oxides
摘要： In the previous chapters of this book, we have discussed the consequences of quantum mechanics on the properties of solid state electrons mostly on the single or two particle level. This revealed the important influence of the phase of the electronic wave functions in mesoscopic electronic transport and a general understanding of the optical properties of solids, where the interaction between the electrons led only to relatively simple modifications such as the excitonic binding energy ERyd,X or the dielectric constant of the material ε. In addition, we have learned how to gain an unprecedented control of the quantum mechanical properties, including the dynamics, for single-electron and two-electron systems in spin qubits or in many-particle states in superconducting qubits. There, the electron-electron interaction was mostly used as an exchange coupling or as a classical repulsive energy for read-out.
关键词： spin qubits,electron-electron interaction,mesoscopic electronic transport,excitonic binding energy,superconducting qubits,dielectric constant,solid state electrons,quantum mechanics,optical properties of solids
更新于2025-09-16 10:30:52
-
Dielectric Anisotropy Sensor Using Coupled Resonators
摘要： In this article, a new approach is proposed for the measurement of the uniaxial anisotropic dielectric constant of different planar samples by means of a single sensor. The sensor is based on a couple of straight-line coupled resonators in microstrip technology that can be excited in odd and even propagation modes. This sensor is designed on an isotropic substrate at the design frequency. Due to the electric field configuration specific for each mode, it is possible to relate these modes to the dielectric constant in two different directions (parallel and perpendicular) of a dielectric material placed on top of the sensor. This technique is used for the successful characterization of the dielectric constant anisotropic of anisotropic dielectrics (FR4, Rogers 4350B, and Arlon Diclad 880), and the isotropic material PTFE.
关键词： FR4,Anisotropic,dielectric constant,printed circuit board (PCB),uniaxial,anisotropy,sample under test (SUT)
更新于2025-09-16 10:30:52
-
Response Properties of Gold- and Aluminum-deposited SPR-based Glass Rod Sensors Using Light-emitting Diodes with Various Wavelengths; 各種波長の発光ダイオードを用いる金とアルミニウムを蒸着したガラス棒SPRセンサーの応答特性;
摘要： The response curves of gold (Au)- and aluminum (Al)-deposited surface plasmon resonance (SPR)-based glass rod sensors with various light-emitting diodes (LEDs) of visible and near-infrared emission as the light sources were measured. Au films with thicknesses of 30, 45, and 70 nm, and Al films with thicknesses of 15, 30, and 45 nm were deposited on half of the surfaces of glass rods of 2 mm in diameter with a deposition length of 100 mm. The LEDs of blue (464 nm), green (533 nm), yellow (591 nm), red (654 nm), and near-infrared (934 nm) emissions for Au films, and those of violet (402 nm), blue, green, yellow, red emissions for Al were used. The response curves of these sensors, calculated using a multi-layer Fresnel equation using various dielectric constants for the emission wavelengths reported in literatures, were compared with those obtained in the measurements. The important parameters for the calculations were the LED intensity distribution, the range of the angle of incidence of light into the sensor element, and the thickness distributions of the metal films deposited on the glass rods. Native oxide layers with a thickness of 3.0 nm were considered for Al films. The minimum positions of the experimental response curves agreed well with those of the theoretical response curves within the limits of the experimental uncertainties, though those of the experimental response curves using the LED of near-infrared emission shifted to higher refractivity values, mainly due to the wide wavelength distribution to longer wavelengths of the LED. The agreements between the experimental and theoretical response curves indicate both the potential and the usefulness of the sensor performance estimation process based on the multi-layer Fresnel equation. It was also found that the value of the ratio of the real and imaginary part of the dielectric constant is an easy and useful estimation for SPR.
关键词： multi-layer Fresnel equation,dielectric constant,Au,metal-deposited SPR-based glass rod sensor,Al
更新于2025-09-16 10:30:52
-
New Conjugated Polymers Based on Dithieno[2,3‐e:3′,2′‐g]Isoindole‐7,9(8H)‐Dione Derivatives for Applications in Nonfullerene Polymer Solar Cells
摘要： We have designed two new wide bandgap A1-D1-A2-D1 conjugated polymers with same dithieno[2,3-e:3’,2’-g]isoindole-7,9(8H)-dione (DTID) acceptor (A1) and D1 (thiophene donor) and different A2 acceptor units i.e. benzothiadiazole (BT) and fluorinated benzothiadiazole (f-BT) denoted as P113 and P114 and investigated the effect of fluorination the benzothiadiazole acceptor unit on photovoltaic properties of polymer solar cells using non-fullerene acceptor. We found that the incorporation of fluorine atom into the benzothiadiazole acceptor unit increases the absorption coefficients and the relative dielectric constant. The increase in the photoluminescence quenching, reduction in charge recombination loss and improvement in the charge carrier life are observed for the P114. These all factors resulted in dramatically improved the power conversion efficiency of P114:ITIC-m based polymer solar cell to 10.42 % with small energy loss of 0.56 eV as compared to P113 counterpart (8.74 % with energy loss of 0.69 eV) under identical conditions. The low energy loss is beneficial to overcome the trade-off between open circuit voltage and short circuit current.
关键词： low energy loss,dielectric constant,Polymer solar cells,power conversion efficiency,fluorinated backbone
更新于2025-09-12 10:27:22
-
Nonlinear Fiber Optics || Pulse propagation in fibers
摘要： For an understanding of the nonlinear phenomena in optical ?bers, it is necessary to consider the theory of electromagnetic wave propagation in dispersive nonlinear media. The objective of this chapter is to obtain a basic equation that governs propagation of optical pulses in single-mode ?bers. Section 2.1 introduces Maxwell’s equations and important concepts such as the linear and nonlinear parts of the induced polarization and the frequency-dependent dielectric constant. The concept of ?ber modes is introduced in Section 2.2 where the single-mode condition is also discussed. Section 2.3 considers the theory of pulse propagation in nonlinear dispersive media in the slowly varying envelope approximation with the assumption that the spectral width of the pulse is much smaller than the frequency of the incident radiation. The numerical methods used to solve the resulting propagation equation are discussed in Section 2.4.
关键词： electromagnetic wave propagation,dispersive nonlinear media,numerical methods,nonlinear phenomena,optical fibers,single-mode fibers,fiber modes,pulse propagation,dielectric constant,induced polarization,Maxwell’s equations
更新于2025-09-12 10:27:22
-
Investigation of the optical properties of CuIn (Se,S)2 thin films for photovoltaic application
摘要： In this study, thin CuInSe2 and CuInS2 ternary films were successfully deposited on Indium ThinOxide (ITO) substrates by a low-cost electrochemical deposition technique.During the deposition of thin layers, the pH of the solution was maintained at 1.6, the applied potential at -0.750 V and the deposition time at 60 minutes, to control the ionic concentration of the solution; Sodium citrate has been used as a complexing agent.The morphology of the films was examined by optical microscopy, a homogeneous and without pin hole films were founded based on sulfur compared to those prepared with selenium precursor.Optical parameters such as absorbance (A), transmittance (T), band gap energy (Eg) and optical constants like refractive index (n), extinction coefficient (k) and dielectric constant (ε) were extracted using UV-Vis spectroscopy.It is remarkable that all films have a high absorption capacity and low transmittance. But there is a small difference in the results in terms of percentage (%) of the absorbance and transmittance of the films. The highest transmittance value is observed for selenium (12%) with band gap energy about 1.52 eV and for the deposited film with sulfur the lower transparency of 9% at 800 nm with band gap energy about 1.46 eV.The higher value of the refractive index (3.5) for films prepared using sulfur as a precursor is attributed to the thickness (1.99 μm) of the films andthe important value of the extinction coefficient (0.055) is observed for this precursor because of the strong absorption of this film.
关键词： Gap,Spectroscopy,Dielectric constant,CuInSe2,Refractive index,CuInS2,Thin films
更新于2025-09-12 10:27:22