• Title/Summary/Keyword: Direct current

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Perspective for Clinical Application and Research of Transcranial Direct Current Stimulation in Physical Therapy

  • Kim, Chung-Sun;Nam, Seok-Hyun
    • The Journal of Korean Physical Therapy
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    • v.22 no.6
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    • pp.91-98
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    • 2010
  • Neurostimulation approaches have been developed and explored to modulate neuroplastic changes of cortical function in human brain. As one of the most primary noninvasive tools, transcranial direct current stimulation (tDCS) was extensively studied in the field of neuroscience. The alternation of cortical neurons depending on the polarity of the tDCS has been used for improving cognitive processing including working memory, learning, and language in normal individuals, as well as in patients with neurological or psychiatric diseases. In addition, tDCS has great advantages: it is a non-invasive, painless, safe, and cost-effective approach to enhance brain function in normal subjects and patients with neurological disorders. Numerous previous studies have confirmed the efficacy of tDCS. However, tDCS has not been considered for clinical applications and research in the field of physical therapy. Therefore, this review will focus on the general principles of tDCS and its related application parameters, and provide consideration of motor behavioral research and clinical applications in physical therapy.

APPLICATION OF DIRECT LEAKAGE CURRENT METHOD FOR AGING DIAGNOSIS EVALUAT10N (열화 진단 평가를 위한 직류 누설법의 활용)

  • 이관우;박대희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.149-152
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    • 2001
  • In this paper, aging diagnosis method of CV cable was investigated. CV cable was designed for the sake of using during 30 years. Therefore it was important to evaluate the cable's remaining life because CV cable used for power transmission line since 1970's. CV cable was mainly installed at the underground owing to the environmental condition. If the cable accident occurred, it needs the much time for the accident recovery and the much damage at the industrial activity. therefore, this paper should study the direct leakage current method, a sort of the cables'aging test method.

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An IPM(Intelligent Power Module) performance evaluation system for the driving of a multi-pole BLDC motor (다극 BLDC 전동기 구동을 위한 IPM(Intelligent Power Module) 성능 평가 시스템)

  • Min, Bung-kil;Kunn, Young;Hwang, Min-kyu;Choi, Jung-keyng
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.05a
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    • pp.686-689
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    • 2014
  • This Paper is about the study that use the IPM(Intelligent Power Module) which is a integrated switching module to drive inverter gates for driving of a multi-pole BLDC(Brushless Direct Current) motors. When designing a inverter using the various manufacturers IPM, it suggests a electronic circuit system to evaluate the electrical and logical characteristics of the IPM with various brands.

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LOW DIRECT-PATH SHORT CIRCUIT CURRENT OF THE CMOS DIGITAL DRIVER CIRCUIT

  • Parnklang, Jirawath;Manasaprom, Ampaul;Laowanichpong, Nut
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.970-973
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    • 2003
  • Abstract An idea to redce the direct-path short circuit current of the CMOS digital integrated circuit is present. The sample circuit model of the CMOS digital circuit is the CMOS current-control digital output driver circuit, which are also suitable for the low voltage supply integrated circuits as the simple digital inverter, are present in this title. The circuit consists of active MOS load as the current control source, which construct from the saturated n-channel and p-channel MOSFET and the general CMOS inverter circuits. The saturated MOSFET bias can control the output current and the frequency response of the circuit. The experimental results show that lower short circuit current control can make the lower frequency response of the circuit.

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A Research for Novel Brushless Direct Current Motor Position Senseless Drive Using Single Current Sensor (단일전류센서를 이용한 브러시리스 직류 전동기의 새로운 센서리스 제어에 관한 연구)

  • Kim, Byung-Bok;Jang, Jae-Wan;Jang, Ki-Bong;Lee, Ju
    • Proceedings of the KIEE Conference
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    • 2003.10b
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    • pp.141-143
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    • 2003
  • This paper proposes a new sensorless drive system for the trapezoidal Brushless Direct Current (BLDC) motor requiring mechanical position or speed sensor. The proposed method is using only one current sensor For this an indirect rotor position sensing method from the periodically variation DC Link current waveform. DC Link current waveform change from high to low when BLDC commutate status. This algorithm was verified by simulations using MATLAB SIMULINK and experiment.

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Electromigration Characteristics in PSG/SiO$_2$ Passivated Al-l%Si Thin Film Interconnections

  • Kim, Jin-Young
    • Journal of Korean Vacuum Science & Technology
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    • v.7 no.2
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    • pp.39-44
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    • 2003
  • Recent ULSI and multilevel structure trends in microelectronic devices minimize the line width down to a quarter micron and below, which results in the high current densities in thin film interconnections. Under high current densities, an EM(electromigration) induced failure becomes one of the critical problems in a microelectronic device. This study is to improve thin film interconnection materials by investigating the EM characteristics in PSG(phosphosilicate glass)/SiO$_2$ passivated Al-l%Si thin film interconnections. Straight line patterns, wide and narrow link type patterns, and meander type patterns, etc. were fabricated by a standard photholithography process. The main results are as follows. The current crowding effects result in the decrease of the lifetime in thin film interconnections. The electric field effects accelerate the decrease of lifetime in the double-layered thin film interconnections. The lifetime of interconnections also depends upon the current conditions of P.D.C.(pulsed direct current) frequencies applied at the same duty factor.

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Study on Electrically Assisted Pressure Solid State Joining Between Aluminum Alloys (통전압접을 활용한 알루미늄 소재 간 고상접합에 관한 연구)

  • Choi, H.;Lee, S.;Kim, Y.;Hong, S.T;Han, H.N.
    • Transactions of Materials Processing
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    • v.31 no.6
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    • pp.337-343
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    • 2022
  • Electrically assisted pressure joining (EAPJ) utilizes electric current-induced kinetic enhancement to achieve solid state diffusion bonding within a short time. In this study, aluminum alloy specimens, which are known as a hard-to-weld metal, were successfully solid-state joined through EAPJ. The bonding process was performed in two ways: continuous direct current (CDC), which applies relatively low current density, and pulsed direct current (PDC), which applies high current density. It was observed that the bonding strength was higher in PDC than in CDC. The microstructure of the joint was characterized using 3D X-ray microscopy (XRM) and electron backscatter diffraction (EBSD).

Implantation of DC Optical Current Sensor Based on Faraday Effect for HVDC (페러데이 효과를 이용한 특고압 직류전송용 광전류 센서 구현)

  • Kim, Kwang Taek;Chung, Dae Won;Kim, Young Soo
    • Journal of Sensor Science and Technology
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    • v.28 no.3
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    • pp.187-190
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    • 2019
  • We proposed and demonstrated DC(direct current) optical current sensor based on Faraday effect for HVDC(high voltage direct current). The RIG((Bi1.3Gd0.43Y1.27)Fe5O12) was adopted as Faraday device because of its high Verdet constant and good thermal stability. The differential amplification scheme for signal processing was present. The sensor showed high linear response for the input current. Measurement range of the sensor was 0~200A and measurement error was less than 1%.

A Study on DC Interruption Technology using a Transformer Type Superconducting Fault Current Limiter to Improve DC Grid Stability (DC 그리드 안정성 향상을 위해 변압기형 초전도 한류기가 적용된 직류 차단 기술에 관한 연구)

  • Hwang, Seon-Ho;Choi, Hye-won;Jeong, In-Sung;Choi, Hyo-Sang
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.4
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    • pp.595-599
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    • 2018
  • Interruption system with the transformer type superconducting fault current limiter(TSFCL) is proposed in this paper. The interruption system with a TSFCL is a technology that it maximizes the interruption function of a mechanical DC circuit breaker using a transformer and a superconducting fault current limiter. By a TSFCL, the system limits the fault current till the breakable current range in the fault state. Therefore, the fault current could be cut off by a mechanical DC circuit breaker. The Interruption system with a TSFCL were designed using PSCAD/EMTDC. In addition, the Interruption system with a TSFCL was applied to the DC test circuit to analyze characteristics of a current-limiting and a interruption operation. The simulation results showed that the Interruption system with a TSFCL interrupted the fault current in a stable when a fault occurred. Also, The current-limiting rate of the Interruption system with a TSFCL was approximately 69.55%, and the interruption time was less than 8 ms.

Technology trends in direct conversion receivers

  • Lee, Sang-Gug;Vladimir Krizhanovskii
    • The Magazine of the IEIE
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    • v.29 no.9
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    • pp.48-67
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    • 2002
  • Basic introduction to direct conversion architecture was given in comparison with heterodyne one. Principal difficulties in implementation of direct conversion receiver were presented, current state of research in this field and classified, on the basis of extensive analysis of published materials.

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