The Experts below are selected from a list of 687 Experts worldwide ranked by ideXlab platform
Vladimi Elenkiy - One of the best experts on this subject based on the ideXlab platform.
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signal emitted from plasma during electron beam welding with Deflection oscillations of the beam
Journal of Materials Processing Technology, 2014Co-Authors: E Koleva, Georgi Mladenov, D N Trushnikov, Vladimi ElenkiyAbstract:Abstract The oscillations of a signal, collected by a ring electrode with +50 V potential, situated in the plasma over the welding zone during electron beam welding (EBW) with local beam Deflection oscillations were studied. Samples of chrome-molybdenum steel were processed. The frequencies of the beam oscillations varied between 150 and 1400 Hz and their trajectories were the simplest: along and across the joint. The position of the beam focus was changed. Fluctuations of the emitted plasma current by coherent accumulation of the signal amplitudes were analysed and the probability for instability excitations in the keyhole was estimated. This method allows the study of the random instability processes at the interaction of the beam with the keyhole wall and bottom. A time shift between the maxima of the function derived from the coherent accumulation and the extremes of the Deflection Coil current was found. This shift depends on the beam focus position. In addition, at longitudinal beam oscillations, and at variations of the focus position a difference of the extreme values of the studied signal was observed. At the lowest values of the current of the focusing electromagnetic lens, the differences between the maxima of the probabilities for excitation of the plasma signal oscillations in the moments at beam bombardment on the front and trailing walls of the keyhole in the molten pool were about 30%, while the beam over-focusing decreased these differences. For beams situated at the central part of the keyhole, the collected signal was minimal. From the observations of spikes in the weld root, at EBW with Deflection oscillations, it was concluded that self-focusing of the beam in the bottom part of the keyhole in the cases of the most focusing positions was occurring.
Takahashi Norio - One of the best experts on this subject based on the ideXlab platform.
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Effect of eddy current in shielding plate and electron gun on flux distribution in CRT
'Institute of Electrical and Electronics Engineers (IEEE)', 2002Co-Authors: Takahashi Norio, Ochi Yoshiyuki, Nakano Katsumi, Shimada Koji, Wakasono HiromiAbstract:The eddy current induced in an inner magnetic shield (IMS) and an electron gun affect the flux distribution of a cathode ray tube, causing a possible degrade of picture quality. In this paper, the effect of the distance between an IMS and a Deflection Coil on the eddy-current distribution is examined. The eddy current induced in the electron gun, when the Coils for velocity modulation (VM) are set near the electron gun, is also analyzed. It is found that the variation of flux distribution is mainly affected by the shape of VM Coil.
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Effect of eddy current in shielding plate and electron gun on flux distribution in CRT
'Institute of Electrical and Electronics Engineers (IEEE)', 2002Co-Authors: Takahashi Norio, Shimada Koji, Wakasono H.Abstract:Summary form only given. An inner magnetic shield (IMS) is set inside a cathode ray tube (CRT) to reduce the disturbance from outside of the CRT, such as geomagnetism. The eddy current induced in the IMS due to the changing current in the Deflection Coil may affect the flux distribution in the CRT. The eddy current is also induced in the electron gun when Coils for velocity modulation (VM) are set near the gun. Although the effect of the eddy current is important, reports about the analysis of this phenomenon are few. In this paper, the effect of the eddy current in the IMS and electron gun on flux distribution in the CRT is analyzed by using the 3-D finite element method.
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Effective optimal design of 3-D magnetic device having complicated Coil using edge element and Biot-Savart method
'Institute of Electrical and Electronics Engineers (IEEE)', 2002Co-Authors: Ohnishi Takuma, Takahashi NorioAbstract:It is troublesome and time consuming to treat a Coil of complicated shape with optimization methods using edge elements, because the current vector potential in the Coil of changed shape (changed mesh) should be calculated at each iteration of the optimization. In this paper, an effective optimal design method using the Biot-Savart method (As method) and the evolution strategy is investigated. As it is not necessary to generate a mesh for the Coil by using the As method, the mesh becomes simple and, moreover, it is not necessary to calculate the current vector potential in the changed Coil at each iteration in order to give the current vector potential in the Coil. The usefulness of the proposed method is illustrated by applying it to the optimal design of a Deflection Coil for a cathode-ray tube
E Koleva - One of the best experts on this subject based on the ideXlab platform.
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signal emitted from plasma during electron beam welding with Deflection oscillations of the beam
Journal of Materials Processing Technology, 2014Co-Authors: E Koleva, Georgi Mladenov, D N Trushnikov, Vladimi ElenkiyAbstract:Abstract The oscillations of a signal, collected by a ring electrode with +50 V potential, situated in the plasma over the welding zone during electron beam welding (EBW) with local beam Deflection oscillations were studied. Samples of chrome-molybdenum steel were processed. The frequencies of the beam oscillations varied between 150 and 1400 Hz and their trajectories were the simplest: along and across the joint. The position of the beam focus was changed. Fluctuations of the emitted plasma current by coherent accumulation of the signal amplitudes were analysed and the probability for instability excitations in the keyhole was estimated. This method allows the study of the random instability processes at the interaction of the beam with the keyhole wall and bottom. A time shift between the maxima of the function derived from the coherent accumulation and the extremes of the Deflection Coil current was found. This shift depends on the beam focus position. In addition, at longitudinal beam oscillations, and at variations of the focus position a difference of the extreme values of the studied signal was observed. At the lowest values of the current of the focusing electromagnetic lens, the differences between the maxima of the probabilities for excitation of the plasma signal oscillations in the moments at beam bombardment on the front and trailing walls of the keyhole in the molten pool were about 30%, while the beam over-focusing decreased these differences. For beams situated at the central part of the keyhole, the collected signal was minimal. From the observations of spikes in the weld root, at EBW with Deflection oscillations, it was concluded that self-focusing of the beam in the bottom part of the keyhole in the cases of the most focusing positions was occurring.
Wakasono Hiromi - One of the best experts on this subject based on the ideXlab platform.
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Effect of eddy current in shielding plate and electron gun on flux distribution in CRT
'Institute of Electrical and Electronics Engineers (IEEE)', 2002Co-Authors: Takahashi Norio, Ochi Yoshiyuki, Nakano Katsumi, Shimada Koji, Wakasono HiromiAbstract:The eddy current induced in an inner magnetic shield (IMS) and an electron gun affect the flux distribution of a cathode ray tube, causing a possible degrade of picture quality. In this paper, the effect of the distance between an IMS and a Deflection Coil on the eddy-current distribution is examined. The eddy current induced in the electron gun, when the Coils for velocity modulation (VM) are set near the electron gun, is also analyzed. It is found that the variation of flux distribution is mainly affected by the shape of VM Coil.
D N Trushnikov - One of the best experts on this subject based on the ideXlab platform.
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signal emitted from plasma during electron beam welding with Deflection oscillations of the beam
Journal of Materials Processing Technology, 2014Co-Authors: E Koleva, Georgi Mladenov, D N Trushnikov, Vladimi ElenkiyAbstract:Abstract The oscillations of a signal, collected by a ring electrode with +50 V potential, situated in the plasma over the welding zone during electron beam welding (EBW) with local beam Deflection oscillations were studied. Samples of chrome-molybdenum steel were processed. The frequencies of the beam oscillations varied between 150 and 1400 Hz and their trajectories were the simplest: along and across the joint. The position of the beam focus was changed. Fluctuations of the emitted plasma current by coherent accumulation of the signal amplitudes were analysed and the probability for instability excitations in the keyhole was estimated. This method allows the study of the random instability processes at the interaction of the beam with the keyhole wall and bottom. A time shift between the maxima of the function derived from the coherent accumulation and the extremes of the Deflection Coil current was found. This shift depends on the beam focus position. In addition, at longitudinal beam oscillations, and at variations of the focus position a difference of the extreme values of the studied signal was observed. At the lowest values of the current of the focusing electromagnetic lens, the differences between the maxima of the probabilities for excitation of the plasma signal oscillations in the moments at beam bombardment on the front and trailing walls of the keyhole in the molten pool were about 30%, while the beam over-focusing decreased these differences. For beams situated at the central part of the keyhole, the collected signal was minimal. From the observations of spikes in the weld root, at EBW with Deflection oscillations, it was concluded that self-focusing of the beam in the bottom part of the keyhole in the cases of the most focusing positions was occurring.