• 전기학회논문지
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• 제56권5호
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• pp.933-937
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• 2007

A point plate type nonthermal plasma reactor, with a grounded cylindrical third electrode which closely- encompasses the needle point, have been investigated with an emphasis on the role of the third electrode. It was found that the point plate airgap, with the grounded third electrode, had a switching characteristic on its I V characteristics for negative and positive discharges, which is very different from that of a conventional point plate airgap without a third electrode. The corona discharge and ozone generation characteristics of the plasma reactor with the grounded cylindrical third electrode, such as the corona onset voltage. the breakdown voltage. the corona current. and the amount of output ozone, were influenced significantly by the height of the third electrode. and these characteristics can be controlled by adjusting the height of the third electrode.

• 한국운동역학회지
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• 제30권1호
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• pp.103-109
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• 2020

Objective: The purpose of this study is to compare the muscle activity by electrode location in the biceps brachii during the arm curl isometric exercise and to provide the basic data needed to develop the proper electrode location of the biceps brachii based on the study results comparing the muscle activity by the angle of the elbow joint. Method: 17 adult males (Age: 21.50±4.63 yrs, height: 175.29±5.97 cm, weight: 63.79±15.31 kg, upper-arm length: 30.10±1.22 cm) participated in the study. In the arm curls isometric exercise, the experiment was divided into 1st and 2nd steps to compare muscle activity according to electrode location in the biceps brachii and muscle activity according to elbow angle change. In the first experiment, the surface electrode was attached at one-third point on the line from medial acromion to cubital fossa, according to the measurement method indicated by SENIAM. The elbow angle was set to 90°. In the second experiment, according to the proposed method of this study, the electrodes were separated at one finger's width in the left and right direction at one-third point on the line from medial acromion to cubital fossa, attached at the long head and short head. From the long head electrode, in about a width of two fingers in proximal direction, a total of three electrodes were attached at the myotendinal junction of the long head. The elbow angles were set as 70°, 90°, and 110°, and the isometric exercise (100% MVC) for 5 seconds was maintained with keeping the forearm and the rope to be 90° for the first and second experiments. Results: During the arm curl isometric exercise, there was no significant difference in SH and SENIAM proposition location proposed by this researcher. LH was shown to be lower than the muscle activity of the location proposed by SENIAM and there were significant (p<.01) differences. MJ appeared lower than the muscle activity of the location proposed by SENIAM and there were significant (p<.001) differences. The muscle activity by the elbow joint angle of SH in the biceps brachii was shown in large order of 70°<90°<110°, but there was no significant difference. The muscle activity by the elbow joint angle of LH was shown in large order of 90°<70°<110°, but there was no significant difference. The muscle activity by the elbow joint angle of MJ was shown in large order of 110°<90°<70°, but there was no significant difference. Conclusion: During the arm curl isometric exercise of the biceps brachii, it is judged appropriate to attach surface electrodes to the location proposed by SENIAM.

• Journal of Magnetics
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• 제7권3호
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• pp.63-71
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• 2002

Three fabrication techniques for forming thin barrier layer with uniform thickness and large barrier height in magnetic tunnel junction (MTJ) are discussed. First, the effect of immiscible element addition to Cu layer, a high conducting layer generally placed under the MTJ, is investigated in order to reduce the surface roughness of the bottom ferromagnetic layer, on which the barrier is formed. The Ag addition to the Cu layer successfully realizes the smooth surface of the ferromagnetic layer because of the suppression of the grain growth of Cu. Second, a new plasma source, characterized as low electron energy of 1 eV and high density of $10^{12}$ $cm^{-3}$, is introduced to the Al oxidation process in MTJ fabrication in order to reduce damages to the barrier layer by the ion-bombardment. The magnetotransport properties of the MTJs are investigated as a function of the annealing temperature. As a peculiar feature, the monotonous decrease of resistance area product (RA) is observed with increasing the annealing temperature. The decrease of the RA is due to the decrease of the effective barrier width. Third, the influence of the mixed inert gas species for plasma oxidization process of metallic Al layer on the tunnel magnetoresistance (TMR) was investigated. By the use of Kr-O$_2$ plasma for Al oxidation process, a 58.8 % of MR ratio was obtained at room temperature after annealing the junction at $300{^{\circ}C}$, while the achieved TMR ratio of the MTJ fabricated with usual Ar-$0_2$ plasma remained 48.4%. A faster oxidization rate of the Al layer by using Kr-O$_2$ plasma is a possible cause to prevent the over oxidization of Al layer and to realize a large magnetoresistance.