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ABSTRACT: Space Charge behavior in polyimide film under dc stress with visible light irradiation was carried out using a newly developed measurement system of the pulsed electro-acoustic (PEA) method. The PEA method has been widely used to observe a space charge distribution in various solid dielectric materials. We applied the method to investigate the interaction of visible light irradiation on space charge formation in dielectric materials under DC stress. It is well known that a property of the conduction in dielectric materials is affected by the irradiation of light. However the relationship between the space charge and the irradiation of light haven't been clear yet. To observe the effect of the light irradiation on the space charge distribution in polyimide film, we measured the time dependent space charge distribution under the irradiation of the visible light using three kind of LED. From the results, it is found that the space charge formation in the polyimide film under DC stress with irradiation of visible light is affected by the energy of the irradiated light.
Solid Dielectrics, 2007. ICSD '07. IEEE International Conference on; 08/2007
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ABSTRACT: Nano-composite technology makes it possible to improve dielectric properties, such as resistivity, breakdown strength and so on, under high DC stress. However, the mechanism of the improvement in MgO nano-composite LDPE (LDPE/MgO) has not been clear, yet. We attempted to clarify the mechanism of the improvement on the electrical properties focused on the space charge formation. To investigate the influence of MgO nano-filler on space charge profiles, we measured the space charge distributions using PEA system under DC electric field of 50 to 250 kV/mm. In the case of LDPE without nano-filler, a positive packet-like charge injection with peak charge density of more than several hundred C/m<sup>3</sup> were measured under more than 150 kV/mm. In the case of LDPE/MgO with MgO content of 0.2 phr, an oscillating behavior of packet-like charge was observed when the DC electric field of more than 200 kV/mm was applied to it. On the other hand, in the case of LDPE/MgO with MgO content of more than 0.5 phr, there is no remarkable charge injection. It is thought that space charge behavior is drastically changed by adding only more than 0.5 phr of MgO to LDPE. The nano-composite including more than 0.5 phr shows a superior property to prevent the injection of space charge into bulk
Properties and applications of Dielectric Materials, 2006. 8th International Conference on; 07/2006
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ABSTRACT: A three-dimensional space-charge measurement system using the acoustic lens and PWP method has been developed. The resolutions on the x-y plane and in the z direction of this system are about and m respectively. It takes about 3 s for each sample position and 130 min for positions on the x-y plane for a mm specimen. This speed is much higher than that of the three-dimensional space-charge measurement system using the PEA method. Although the resolutions of this system on the x-y plane and along the z direction are not high, the three-dimensional charge profile of an electron-beam-irradiated PMMA specimen is successfully constructed.
Journal of Physics D Applied Physics 12/1998; 32(2):157. · 2.54 Impact Factor
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ABSTRACT: The pulsed electroacoustic (PEA) method and the piezoelectrically induced pressure wave propagation (PIPWP) method are compared. While the PEA method has been widely used as a measurement technique to observe space charge distributions in solid dielectric materials, the PIPWP method has not been widely used because of its relatively lower spatial resolution as compared to that of the PEA method. Therefore, in this research, an attempt has been made to improve the resolution of the PIPWP method. In this paper, principles of the generation and the detection of pressure waves in both PEA and PIPWP methods are summarized. Furthermore, the two methods are compared through observations of the generation, drift, and trapping of carriers in an organic photoconductor (OPC). © 1997 Scripta Technica, Inc. Electr Eng Jpn, 121(2): 1–7, 1997
Electrical Engineering in Japan 12/1998; 121(2):1 - 7. · 0.09 Impact Factor
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ABSTRACT: The new application of pulsed electroacoustic (PEA) method to measure space charge profiles in several millimeters thick polymers such as power transmission cable was proposed. In this method, space charge profiles are detected as acoustic wave signals that are generated by the space charge profiles existing in the sample under stimulation of an electric pulse. In most polymer samples, such as cross‐linked polyethylene (XLPE) widely used in XLPE cable (CV cable), however, the acoustic wave form is obviously distorted as it propagates through the thick polymer. The acoustic wave distortion cannot be negligible when applying this method directly to very thick samples (several millimeters thick). To recover the wave form and obtain the accurate space charge profiles, it is necessary to study the attenuation and dispersion characteristics of the sample and remove their effects to the propagating acoustic wave. So‐called ‘‘deconvolution processing’’ using ‘‘Jacobi method’’ was employed in this report to obtain the undistorted wave form. The principle of the data processing method is introduced and some examples for recovering the wave form are given to verify the effectiveness of the data processing method. © 1995 American Institute of Physics.
Review of Scientific Instruments 08/1995; · 1.37 Impact Factor
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ABSTRACT: The pulsed electro-acoustic (PEA) method has been widely used to observe
space charge phenomena in dielectric materials. There have been awaited
demands for monitoring space charge phenomena under electron beam or
radioactive rays irradiations, or during plasma processing. Therefore we
have developed a new PEA space charge measurement system that can
observe space charge distributions under such severe conditions. This
system uses an open upper electrode that can measure surface and
internal space charge profiles at the same time. This paper introduces
the 'Open-PEA system' with experimental results obtained during electron
irradiation in vacuum.
IEEJ Transactions on Fundamentals and Materials 126:191-196.
