Application of Dielectric Spectroscopy in ZnO Varistor Ceramics

2011 ◽  
Vol 393-395 ◽  
pp. 24-27 ◽  
Author(s):  
Peng Fei Cheng ◽  
Sheng Tao Li ◽  
Jian Ying Li
Keyword(s):  
Electric Field ◽  
Temperature Region ◽  
Dielectric Spectroscopy ◽  
Low Frequency ◽  
Dielectric Materials ◽  
The Other ◽  
Zno Varistor ◽  
Ac Electric Field ◽  
Wide Range ◽  
Dc Electric Field

There are two kinds of charges in dielectric materials, one is bound charge, and the other is free charge. Bound charge will introduce dielectric relaxation under applied AC electric field, which will be detected with dielectric spectroscopy. Free carrier will introduce DC conduction through the sample from one electrode to the other under DC electric field. But what can we do to obtain AC and DC properties of dielectric materials at the same time? In this paper, dielectric characteristics of ZnO varistor ceramics in a wide range of frequency and temperature are reported. DC conductivity is observed at low frequency and high temperature region and grainboundary Schottky barrier is obtained further. Dielectric loss peaks are observed at high frequency and low temperature region and single grainboundary electric breakdown voltage is calculated. At the end of the paper, the advancing trend of dielectric spectroscopy is discussed.

Electrostatic Dispensing of Dry Dielectric Materials

2001 ◽  
Vol 700 ◽  
Author(s):  
Malinda M. Tupper ◽  
Marjorie E. Chopinaud ◽  
Takamichi Ogawa ◽  
Michael J. Cima
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Dielectric Materials ◽  
Nonuniform Electric Field ◽  
Sodium Fluorescein ◽  
Silica Spheres ◽  
Electrode Geometry ◽  
Wide Range ◽  
Silica Beads

AbstractDispensing micron-scale dielectric materials can be achieved through the use of dielectrophoresis. Electrodes are designed to create a nonuniform electric field. This method is expected to be applicable for transfer of a wide range of dielectric powders as well as small, shaped components. Small, 150 μm diameter silica spheres, as well as sodium fluorescein powder have been dispensed by this method. Selecting the appropriate electrode geometry and electric field intensity controls the amount collected. As little as 1.0 μg of sodium fluorescein powder, and as much as 16 mg of silica beads have been collected, and repeatability within 10 % of the total amount dispensed has been achieved.

Dynamic Response of an Electrospun PVDF-Fe3O4 Piezoelectric Composite Microfiber

2019 ◽  
Author(s):  
Krishna Chytanya Chinnam ◽  
Arnaldo Casalotti ◽  
Giulia Lanzara
Keyword(s):  
Electric Field ◽  
Dynamic Response ◽  
Resonance Frequency ◽  
Piezoelectric Composite ◽  
Test Results ◽  
Ac Electric Field ◽  
Wide Range ◽  
Pvdf Matrix ◽  
Fine Tune

Abstract In this paper the dynamic response of an electrospun nanocomposite piezoelectric microfiber is investigated. The microfiber is formed by magnetic nanoparticles dispersed in Polyvinylidene (PVDF) matrix. Focus is given on the influence of an AC electric field on the dynamic response of the microfiber. In particular, the resonance frequency of the fiber was assessed under an increasing AC electric field at a wide range of frequencies. The electromechanical test results show that the resonance frequency of the fiber is influenced by the applied voltage and, for this case study, it decreases with increasing voltage. The results reported in this paper suggest that, once the mechanism behind such response is fully understood, composite piezoelectric microfibers can be used to fine-tune the resonance frequency of hosting devices.

The Distinguishing Quality of Water Droplets on Insulating Surface under AC and DC Electric Field Stress

2014 ◽  
Vol 1025-1026 ◽  
pp. 803-808
Author(s):  
Sackthavy Chandavong ◽  
Kittipong Tonmitr ◽  
Arkom Kaewrawang
Keyword(s):  
Electric Field ◽  
Water Droplets ◽  
Insulating Material ◽  
Field Stress ◽  
Ac Electric Field ◽  
Quality Of Water ◽  
Electric Field Direction ◽  
Surface Breakdown ◽  
Dc Electric Field

This paper presents the comparison of water droplets on insulating surface under alternating current (AC) and direct current (DC) electric field. Besides that, it is demonstrated about the insulator deterioration under both electric field stressed due to an ageing and partial discharge (PD) phenomenon. The vital parameters factors are water droplets conductivity, droplet volume, surface roughness and droplet positioning that they cause to occur the electric field intensification. The field is intensified at the interface between the droplet, air and insulating material. Thus, the PD occurred due to electric field intensification increases with the deformed droplet. The deformation of water droplet under AC electric field stress is more intense than DC field. The electrostatic forces change the droplet shapes and spread them along the electric field direction. The local electric field intensification provokes the PD giving way to reduction of hydrophobicity of insulator surfaces. In addition, the PD activity could appear as a trigger for a surface breakdown. And the localized arcs cause damage to insulating material then finally leads to deterioration of insulation materials and the pollutant contamination.

Characterization of interactive force acting on colloidal particles near an electrode in presence of a high-frequency (>10 kHz) AC electric field using particle diffusometry

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Kshitiz Gupta ◽  
Dong Hoon Lee ◽  
Steven T. Wereley ◽  
Stuart J. Williams
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Particle Motion ◽  
Electrode Surface ◽  
High Frequency ◽  
Colloidal Particles ◽  
Low Frequency ◽  
Double Layers ◽  
Average Height ◽  
Ac Electric Field

Colloidal particles like polystyrene beads and metallic micro and nanoparticles are known to assemble in crystal-like structures near an electrode surface under both DC and AC electric fields. Various studies have shown that this self-assembly is governed by a balance between an attractive electrohydrodynamic (EHD) force and an induced dipole-dipole repulsion (Trau et al., 1997). The EHD force originates from electrolyte flow caused by interaction between the electric field and the polarized double layers of both the particles and the electrode surface. The particles are found to either aggregate or repel from each other on application of electric field depending on the mobility of the ions in the electrolyte (Woehl et al., 2014). The particle motion in the electrode plane is studied well under various conditions however, not as many references are available in the literature that discuss the effects of the AC electric field on their out-of-plane motion, especially at high frequencies (>10 kHz). Haughey and Earnshaw (1998), and Fagan et al. (2005) have studied the particle motion perpendicular to the electrode plane and their average height from the electrode mostly in presence of DC or low frequency AC (<1 kHz) electric field. However, these studies do not provide enough insight towards the effects of high frequency (>10 kHz) electric field on the particles’ motion perpendicular to the electrode plane.  

Ionic Conductivity Induced Loss of Birefringence of Banana-Shaped Liquid Crystal

2010 ◽  
Vol 428-429 ◽  
pp. 220-223
Author(s):  
Yuan Ming Huang ◽  
Bao Gai Zhai
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Ionic Conductivity ◽  
Electric Field ◽  
Optical Microscopy ◽  
Dielectric Spectroscopy ◽  
Low Frequency ◽  
Triangular Waveform ◽  
Clearing Temperature

The effects of ionic conductivity on the electro-optical properties of a chiral banana-shaped liquid crystal 1,3-phenylene bis{4-[3-chloro-4-(3,7-dimethyloctyloxyl)] phenyliminomethyl} benzoate were investigated with the techniques of polarizing optical microscopy and dielectric spectroscopy. When the banana-shaped liquid crystal was experienced a low-frequency (1 Hz) triangular waveform electric field, its polarizing optical microscopic textures were first turned into gray and then into black at about 95oC, a few degrees lower than the clearing temperature of the banana-shaped liquid crystal. Detailed dielectric spectroscopic characterizations showed that ionic conductivity increased exponentially as the temperature increased from 72 to 110oC. Our results suggested that dominant ionic conductivity near its clearing temperature is responsible for the electric-field induced loss in the birefringence of the banana-shaped liquid crystal.

Characteristic Electrical Actuation of Plasticized Poly(vinyl chloride): Various Electrical Functions in Relation with the Dielectric Plasticizers

2012 ◽  
Vol 79 ◽  
pp. 1-6 ◽  
Author(s):  
Toshihiro Hirai ◽  
Mohammad Ali ◽  
Takafumi Ogiwara ◽  
Daijiro Tsurumi ◽  
Keiichi Yamamoto ◽  
...  
Keyword(s):  
Electric Field ◽  
Vinyl Chloride ◽  
Creep Deformation ◽  
Low Frequency ◽  
Field Application ◽  
Anode Surface ◽  
Electrical Actuation ◽  
Poly Vinyl Chloride ◽  
Bending Actuator ◽  
Dc Electric Field

Poly(vinyl chloride) (PVC) has been found to be actuated by applying dc electric field, accompanying colossal strain on the anode surface, particularly when plasticized with large amount of plasticizer [1]. We call the plasticized PVC as PVC gel for convenience in this paper. The deformation has been explained only phenomenologically. However, impedance spectroscopy revealed recently the some fundamental mechanism of the actuation, that is, the deformation depends on the dielectric nature of the materials. The colossal increase of dielectric constant was induced in the gel in the low frequency range. The dependency is strongly depends on the nature of the plasticizer and its content. The phenomena observed as electrical actuation of the PVC gels were (1) Creep deformation on the anode surface, (2) Creep induced bending motion, (3) Tacking to the anode, (4) Contractile deformation, and (5) Vibrational motion by dc electric field application. Creep deformation and the excellent transparency of the gel can be utilized for focus controllable lens. Tacking force can be applied various in combination with bending deformation. Bending actuator has been successfully applied micro-finger actuator and passed for hundreds thousands times continuous operation. In this paper, we will introduce not only the various features of the actuation, but also will get into the some detailed mechanism of the deformation.

scholarly journals Polyaniline/Polystyrene Blends: In-Depth Analysis of the Effect of Sulfonic Acid Dopant Concentration on AC Conductivity Using Broadband Dielectric Spectroscopy

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Noora Al-Thani ◽  
Mohammad K. Hassan ◽  
Jolly Bhadra
Keyword(s):  
Dielectric Spectroscopy ◽  
Ac Conductivity ◽  
Sulfonic Acid ◽  
Low Frequency ◽  
Lone Pair ◽  
Interfacial Polarization ◽  
Low Frequencies ◽  
Broadband Dielectric Spectroscopy ◽  
Wide Range ◽  
Depth Analysis

This work presents an in-depth analysis of the alternating current (AC) conductivity of polyaniline-polystyrene (PANI-PS) blends doped with camphor sulfonic acid (CSA) and prepared using an in situ dispersion polymerization technique. We prepared the blends using fixed ratios of PS to PANI while varying the concentration of the CSA dopant. The AC conductivity of the blends was investigated using broadband dielectric spectroscopy. Increasing CSA resulted in a decrease in the AC conductivity of the blends. This behaviour was explained in terms of the availability of a lone pair of electrons of the NH groups in the polyaniline, which are typically attacked by the electron-withdrawing sulfonic acid groups of CSA. The conductivity is discussed in terms of changes in the dielectric permittivity storage (ε′), loss (ε′′), and modulus (M′′) of the blends over a wide range of temperatures. This is linked to the glass transition temperature of the PANI. Dielectric spectra at low frequencies indicated the presence of pronounced Maxwell-Wagner-Sillars (MWS) interfacial polarization, especially in samples with a low concentration of CSA. Electrical conduction activation energies for the blends were also calculated using the temperature dependence of the direct current (DC) conductivity at a low frequency (σdc), which exhibit an Arrhenius behaviour with respect to temperature. Scanning electron microscopy revealed a fibrous morphology for the pure PANI, while the blends showed agglomeration with increasing CSA concentrations.

scholarly journals A New Method for Immobilization of His-Tagged Proteins with the Application of Low-Frequency AC Electric Field

Sensors ◽  
2018 ◽  
Vol 18 (3) ◽  
pp. 784 ◽  
Author(s):  
Shunsuke Takahashi ◽  
Kazuki Kishi ◽  
Ryota Hiraga ◽  
Kazuki Hayashi ◽  
Youhei Mamada ◽  
...  
Keyword(s):  
Electric Field ◽  
Low Frequency ◽  
New Method ◽  
Ac Electric Field

Effects of AC/DC Electric Fields on Stretching DNA Molecules

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050065
Author(s):  
Ying Wang ◽  
Mingyan Gao ◽  
Yingmin Qu ◽  
Jun Hu ◽  
Ying Xie ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Dna Molecules ◽  
Dna Interactions ◽  
Biophysical Properties ◽  
Voltage Range ◽  
Atomic Force ◽  
Ac Electric Field ◽  
Dc Electric Field ◽  
Dc Electric Fields

The effects of AC/DC electric fields on stretching DNA molecules were discussed in this work. In the experiments of stretching DNA molecules with AC/DC electric fields, the voltage range was changed from 0[Formula: see text]V to 10[Formula: see text]V, and the frequency of AC electric field was kept at 50[Formula: see text]kHz. An atomic force microscope (AFM) was used to obtain DNA distributions under different electric fields. DNA molecules were curved and randomly distributed in solution if there was not any force applied to them. When an AC electric field was applied to the DNA sample, the curvature of DNA molecules was decreased gradually, and the stretching result was more obvious with the increase of voltage from 0.1[Formula: see text]V to 5[Formula: see text]V. The DNA molecules were broken when the voltage was increased to 6[Formula: see text]V. However, under the DC electric field, the stretching result of DNA molecules reached to their optimum state when the voltage was 2[Formula: see text]V, and they kept their steady state even though larger electric field intensities applied to the electrodes. The results can be used for the study of DNA–DNA, protein–DNA and quantum dot–DNA interactions and for the exploration of DNA biophysical properties.

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