- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Polarization and acoustic properties of barium-modified lead-free potassium–sodium niobate ceramics
摘要： Results of polarization and polarization switching in samples prepared by solid phase synthesis of the (1-х)(K0.5Na0.5)(Nb0.93Sb0.07)O3–xBaTiO3 + 0.5mol%MnO2 system at x = 0.01, 0.02, and 0.04 (KNNS7–xBT) studied over a wide range of temperatures are reported. The observed features of the dielectric nonlinearity at the ferroelectric and structural phase transitions in the materials are described. The dielectric response data of the samples of different contents of the admixture in the KNNS7–xВT ceramics are compared with the behaviour of their elastic properties.
关键词： dielectric permittivity,polarization,solid solutions,elastic properties,relaxors,ferroelectrics,ceramics
更新于2025-09-23 15:23:52
-
Enhanced performance of porous silicone-based dielectric elastomeric composites by low filler content of Ag@SiO <sub/>2</sub> Core-Shell nanoparticles
摘要： In the present work, micropores and a low filler content of Ag@SiO2 nanoparticles (NPs) are synchronously introduced into polydimethylsiloxane (PDMS) film to obtain porous dielectric elastomeric composites. The morphology and dielectric and mechanical properties of the composites are investigated. The resulting composites possess high dielectric permittivity, low dielectric loss and low Young’s modulus, which is beneficial to the requirements of a dielectric elastomer actuator. This study provides an effective method to prepare high-performance PDMS-based dielectric porous dielectric elastomeric composites filled with low filler contents of Ag@SiO2 NPs.
关键词： core-shell particles,dielectric loss,Young’s modulus,dielectric permittivity,elastomer,Porous materials
更新于2025-09-23 15:22:29
-
ELECTRODELESS MEASUREMENT TECHNIQUE OF COMPLEX DIELECTRIC PERMITTIVITY OF HIGH-K DIELECTRIC FILMS IN THE MILLIMETER WAVELENGTH RANGE
摘要： An electrodeless measurement technique of complex dielectric permittivity of high-K dielectric ?lms is described. The technique is based on a quasi-optic Fabry-Perot resonator and modi?ed for investigation of two-layer dielectric structures — substrate/K-?lm. This procedure is destined to be used for providing a simple intermediate control of parameters of high-K ?lms before the following technological process. Regimes of measurements providing the most sensitive conditions for de?nition of ?lm parameters are considered. The proposed method is tested on two-layer structures with well-known parameters and is used for characterization of ferroelectric (Ba,Sr)TiO3 ?lms in the millimeter wavelength range (～ 50 GHz).
关键词： Fabry-Perot resonator,complex dielectric permittivity,electrodeless measurement,millimeter wavelength range,high-K dielectric films
更新于2025-09-23 15:21:21
-
Electrical response in poled (Bi <sub/>0.5</sub> Na <sub/>0.5</sub> ) <sub/>0.935</sub> Ba <sub/>0.065</sub> TiO <sub/>3</sub> ceramics
摘要： A ferroelectric material (Bi0.5Na0.5)0.935Ba0.065TiO3 (BNBT) with a perovskite structure was poled and characterized by electrical impedance spectroscopy as a function of temperature, X-ray diffraction, and Rietveld refinement. The ac conductivity showed a low-frequency dispersion, supporting the idea of heterogeneous potential wells favored by Bi3+, Na+, and Ba2+ on the A site of the perovskite type of structure. The activation energies for ac conduction depend on the studied frequency. The permittivity and electrical modulus showed a distribution of the relaxation time associated with the delay in the orientation of the dipoles and an important contribution to the short-range conductivity.
关键词： electrical behavior,Rietveld refinement,Phase change,dielectric permittivity,BNBT
更新于2025-09-23 15:21:01
-
Broad-band measurements of dielectric permittivity in coaxial line using partially filled circular waveguide
摘要： The full-wave analysis was applied for a coaxial line (i.e., transmission line) that has a “short-circuited” discontinuity. The discontinuity has a radius less than or equal to the inner radius of the coaxial line. The “sample region” can be considered as a partially filled circular waveguide. Such a structure is very practical and is of particular interest for the dielectric spectroscopy applications. It takes into account the inhomogeneous field distribution, which is the limiting factor for the determination of high dielectric permittivity values at microwave frequencies. The direct problem was solved by using the mode-matching technique, and the relationship between the complex reflection coefficient and the dielectric permittivity of the cylindrical sample was obtained. By solving the inverse problem, it is possible to obtain the complex dielectric permittivity from the experimental values of the scattering matrix. The results were verified by the finite element modeling of the system and applied for particular materials. The correspondence between these approaches is excellent. This method is very suitable for the determination of permittivity, which exceeds several thousands (it is applicable for any type of material). It extends the frequency range where the permittivity can be determined reliably. There is no necessity to prepare samples with different geometries (i.e., surface area and thickness).
关键词： dielectric permittivity,coaxial line,circular waveguide,mode-matching technique,finite element modeling
更新于2025-09-23 15:21:01
-
[IEEE 2018 International Conference on Information and Telecommunication Technologies and Radio Electronics (UkrMiCo) - Odessa, Ukraine (2018.9.10-2018.9.14)] 2018 International Conference on Information and Telecommunication Technologies and Radio Electronics (UkrMiCo) - Micromechanical Tuning of Coplanar Waveguide Based Resonator
摘要： The paper extends idea of micromechanical tuning principle on coplanar waveguide based resonators. Finite elements and finite integral methods were used for electromagnetic problem solution. Presented simulation of signal electrode lift above substrate and dielectric body hover above the line surface demonstrates good tunability accompanied with low loss. Resonator based on tunable coplanar waveguide reaches tuning range up to 50% with displacement under 100 micrometres. Equivalent circuit of tunable CPW based band-stop stub filter is proposed.
关键词： frequency tuning,stub resonator,CPW,effective dielectric permittivity
更新于2025-09-23 15:21:01
-
Investigations of nano-crystalline Sr0.5Ba0.5Nb2O6 and bulk ceramics synthesized by a polymerization method using PEG400
摘要： Nano-crystalline Sr0.5Ba0.5Nb2O6 was synthesized by a one-pot method using PEG400 and citric acid. Calcination of the (Sr,Ba,Nb)-gel at 600 °C leads to Sr0.5Ba0.5Nb2O6 with a crystallite size of 24(2) nm and a specific surface area of 38.5(10) m2 g?1. Sintering up to 1325 °C leads to ceramics with globular or irregular-shaped grains and average grain sizes between 1.3 and 2.4 μm, whereas higher temperatures lead to a rod-like microstructure. The indirect allowed optical band gap varies between 3.70(5) and 3.29(5) eV. Dielectric measurements show a diffuse phase transition and weak relaxor properties. The maximum of the permittivity occurs between 116 and 147 °C. The frequency dependence of the impedance can be well described by one or two RC-circuits depending on sintering temperature. The melting temperature is determined as 1506(7) °C with ΔHf = 140(20) kJ mol?1. The average linear thermal expansion coefficient is found to be 10.5(5)?10?6 K?1.
关键词： Nano-particle,Strontium barium niobate,Band-gap,Dielectric permittivity,Tungsten bronze
更新于2025-09-23 15:21:01
-
Terahertz shielding properties of aero-GaN
摘要： The electrodynamic properties of the first aero-material based on compound semiconductor, namely of Aero-GaN, in the terahertz frequency region are experimentally investigated. Spectra of complex dielectric permittivity, refractive index, surface impedance are measured at frequencies 4-100 cm-1 and in the temperature interval 4 – 300 K. The shielding properties are found based on experimental data. The aero-material shows excellent shielding effectiveness in the frequency range from 0.1 THz to 1.3 THz, exceeding 40 dB in a huge frequency bandwidth, which is of high interest for industrial applications. These results place the aero-GaN among the best THz shielding materials known today.
关键词： Complex dielectric permittivity,THz shielding,Aero-GaN
更新于2025-09-23 15:19:57
-
An eye on molecular interaction studies of non-aqueous binary liquid mixtures with reference to dielectric, refractive properties and spectral characteristics
摘要： This review article presents an overview of the various molecular interactions (inter/intra) that exist between different non aqueous binary mixtures. The content of this article briefly summarizes the scope of scrutinizing and analysing the various intermolecular interactions through dielectric studies, refractive measurements and spectroscopic investigations. The feasible associations between solute-solvent and solvent-solvent molecules demonstrate the advent of this novel phenomenon, which is completely absent in pure state. With the aid of excess values, the deviations from ideal behaviour are articulated by different parameters (dielectric constant and refractive index). Different literatures are cited that focus the aforementioned features. The theme of this article is illustrated in the sketch given above.
关键词： Refractive Index,Dielectric permittivity,Spectroscopic Analysis,Binary Mixture.
更新于2025-09-19 17:15:36
-
Research on epoxy-based nanocomposites with high energy density and charge-discharge efficiency filled with Ti0 <sub/>2</sub> nanofibers
摘要： Capacitor films with high energy density are critical to energy storage. However, the energy density of state-of-the-art commercial capacitor films are limited by their low dielectric permittivity. In this study, epoxy-based nanocomposite films are prepared by filling with TiO2 nanofibers. Results show that nanocomposite films have larger discharge energy density because of the significant increase in dielectric permittivity, which caused by the additional interface polarization and space charge polarization. And a superior charge-discharge efficiency is achieved in the composite films at the same time due to the low dielectric loss. In addition, the composites also keep a high breakdown strength because of the dispersion of the nanofibers. The discharge energy density of 5.19 J/cm3 with the efficiency of 80% is achieved at 470 MV/m in the nanocomposites containing 2wt% nanofibers. The excellent energy density and charge-discharge efficiency of epoxy-based nanocomposites offer a promising opportunity for future researches and industrial application.
关键词： dielectric permittivity,energy density,epoxy-based nanocomposites,charge-discharge efficiency,TiO2 nanofibers
更新于2025-09-16 10:30:52