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Multiferroic materials represent a very attractive class of materials due to the coupling between their electric and magnetic orders. A recent paper has demonstrated that a thin film of BDFO shows a good magnetoelectric coupling. Based on such a peculiarity, multiferroic composites can be successfully used to realize sensors of both electric and magnetic fields. This work reports two different ways...
Experimental results leading to breakdown voltage (BDV) measurements conducted with blade-blade, hemisphere-hemisphere and needle-plane electrode configuration in air at STP have been reported in this paper. The applied voltage was 50Hz AC, the electrode material effect on the BDV's was studied in the needle-plane configuration by changing the plane electrode material. Electric field plots for various...
Recently, we have experimentally demonstrated a bipolar RRAM selector based on punch-through diode using an NPN stack by Si epitaxy (NPN selector). Historically, Metal-Insulator-Metal (MIM) selector has been a promising candidate as a bipolar RRAM selector due to low processing temperature which may enable back-end compatible stacked RRAM. In this report, we present an electrical performance comparison...
Real-time three dimensional simulations of the electrical tree initiation process in needle-plane geometry under DC field with practical parameters were conducted. The evolution of physical parameters in this dynamic process was presented. Three governing equations: the continuity equation, the transport equation and the Poisson equation, were used to describe charge injection and motion, and an iteration...
It is needed for the insulation system of inverter-fed motors used for industrial motors and electric vehicle to have high partial discharge inception voltage (PDIV). In this paper PDIV test was performed on twisted pair specimens of enameled wires consisting of polyamide-imide resin and polyester-imide resin alternately-layered. PDIV characteristics of the twisted pair specimens were measured by...
This paper provides an introduction to high-power electromagnetics. For the nuclear electromagnetic pulse, lightning, high-power microwave coupling, and some of the more energetic forms of electromagnetic compatibility problems, the fields are often high enough to produce nonlinear response in the scattering and coupling materials — often air. At lower fields, circuits and some magnetic materials...
This paper focuses on analyzing the electric field and temperature distribution in a typical stress grading system used in medium voltage rotating machines under pulse width modulation voltage source conditions. Two analysis models for electric field and heat transfer processes are developed to take into account the nonlinear relationship between the electric field and the electrical conductivity...
In this paper, we report the simulation of electrical field distribution and growth of gradient arrayed TiO2 nanotubes by electrochemical anodization. A rectangle electrochemical electrode configuration, in which the end of cathode (Pt wire) is perpendicularly pointed to anode surface (Ti foil), is applied in NH4F glycol electrolyte. Electric field distribution on the surface of the titanium foil...
Materials properties of nitride semiconductors make them superior candidates for power electronics applications. Materials quality, strongly non-uniform field distribution, variations of parameters from device to device, and reliability problems have to be improved or resolved. New designs, especially suitable to nitride devices, include the use of Low Conducting Layers, “composite channel structures,...
The feasibility of a core-shell particle to mimic the behavior of an RLC circuit is examined. In particular, under the quasi-static limit, the conditions are derived that allow for this type of particle to exhibit a high-impedance and a high-admittance response. These conditions dictate that the core and the shell are comprised of material characterized by positive and negative permittivity, respectively...
Charge packet under high electric dc fields has been observed in polyethylene and its formation has been closely associated with ageing and breakdown of the insulating material. To understand the mechanisms several models have been proposed. In this paper, two models originated from completely different approaches have been reviewed. The first model proposed is based on bipolar charge injection together...
Valve side outlet device, which consists of bushing terminal and surrounding barrier system, is the insulation structure located in the connection part between valve winding lead and bushing. The insulation structure of outlet device is made up of oil and paperboard. It is the most complicated and the most important insulation part in converter transformer, and it not only withstands AC voltage, but...
In extra high voltage transmission systems, the accumulation of space charges in polymeric materials have an important influence on the aging and breakdown of power equipments. It has been reported that space charges are mainly determined by trap distribution. Therefore, it is important to understand the influence of trap depths on space charges accumulation in insulating material. In this paper,...
It is well known that amorphous ice can be used to cryopreserve biomaterials for transplantation. The main issue in this process is that liquid-solid phase transition of water. Due to the polarization of water, amorphous ice may be induced by AC electric filed. In this paper, AC electric field was applied to cryopreserve red blood cells (RBCs) to improve their viability. First, an electro-controlling...
Effect of electron beam irradiation on dielectric properties in various insulating materials for spacecraft is investigated using PEA (Pulsed Electro-Acoustic) method. In space environment, spacecraft is exposed to plasma or radioactive-rays. In such condition, multilayer insulating materials covering the spacecraft are charged up. Sometimes the charge accumulation causes to the serious damage to...
One of the major issues to be considered for the development of polymeric-type DC cable systems is the accumulation of space charges and the consequent distortion of the electric field. These phenomena occur both in the cable and in the accessories, especially at interfaces between different materials. In this respect, accessories, like joints and terminations are key points for the reliability of...
The lifetime of insulators for Ultra High Voltage Overhead Transmission Lines (UHV OHTL) for voltages of 765 kV or 1100 kV is currently restricted to limited years due to unknown effects regarding the onset of streamer discharge. To overcome this limit special insulators are developed that incorporate a microvaristor layer thus restricting the peak field strength to 0.5 kV/mm (according to the switching...
This paper concerns several epoxy resin nanocomposites. A DER 332 epoxy resin was chosen as matrix and nanosilica and/or Boron Nitride were chosen as fillers. Conduction currents results obtained using Polarization and Depolarization Current (PDC) tests at room temperature are presented and discussed. Different conduction phenomena were observed following the analysis of the variation of the current...
Systems emitting High-Power Microwave Ultra-Wideband (HPM/UWB) pulses are developed for both military and civilian applications. The knowledge of the biological effects of this type of radiation is crucial for the protection of the staffs involved in the development of UWB systems but also with respect to their future applications. The French-German Research Institute of Saint-Louis has initiated...
A good quality graphene is transferred onto honeycomb-like CNTs arrays with inner supporting CNTs. The efficient field emission is demonstrated due to a high aspect ratio protrusions and graphene crack edges. A high efficient current density about 1.2 mA/cm2 at threshold electric field of 7.8 V/μm with a turn-on electric field of 1.8 V/μm at the current density of 10 μA/cm2 is observed due to high...
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