• 제목/요약/키워드: electrical field

검색결과 8,637건 처리시간 0.039초

불평등 전계 하 액체유동 내 입자 운동 해석 (Analysis of Particles Motion in Liquid Flow in Non-uniform Electric Field)

  • 정한백;서경식;최찬영;박일한
    • 전기학회논문지P
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    • 제66권3호
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    • pp.139-143
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    • 2017
  • In this paper, we propose a separation method of the dielectric particles in the liquid flow. Since particles are dielectric in most cases, they experience dielectrophoretic(DEP) force under non-uniform electric field. The field characteristics in the electromagnetic and fluid dynamic systems are solved by using the finite element method. The motional equation of the particles is calculated by the Runge-Kutta method. The field analysis shows the feasibility of the proposed method. The particle separation model with large DEP force exerting on particles is designed by analyzing field characteristics.

부극성 직류 코로나 방전에 미치는 자계의 영향 (Effect of Magnetic Field on Negative DC Corona Discharge)

  • 박재윤;김익균;정장근;김건호;김정달;고희석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 E
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    • pp.2308-2310
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    • 1999
  • The effect of magnetic field on NOx removal characteristics from a combustion flue gas has been experimentally investigated for a DC corona discharge reactor with a multipoint plate geometry in our Lab. Combustion flue gas removal efficiency of this type was much higher than that of the other types. In this paper, needle-plate geometry discharge system with applied magnetic field at a right angle to the electric field was made. Input power source was used negative DC. The corona discharge characteristics for this system was investigated and compared with the corona characteristics for the corona discharge system without magnetic field.

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자기 공명 영상을 이용한 불균일 자계 측정 알고리즘 (Magnetic field Inhomogeneity measurement algorithm using magnetic resonance)

  • 강휴정;김치영;한수영;윤종호;안창범
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 G
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    • pp.2809-2811
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    • 1999
  • In this paper, we develope an algorithm to calculate field inhomogeneity in MR imaging using a dual fast spin echo pulse sequence. Because phase modulation time can be easily modified with this pulse sequence, high resolution image can be obtained and acquisition time can be reduced compared to gradient echo technique. In the case of phase wrapping in field map, phase corrected using image processing technique. We assume the field pattern to be second order polynomial and apply Pseudo-Inverse equation to calculate second order polynomial coefficients. These coefficients can be used for the shimming of the magnetic field.

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Development of magnetic field measurement system for AMS cyclotron

  • Ho Namgoong;Hyojeong Choi;Mitra Ghergherehchi;Donghyup Ha;Mustafa Mumyapan;Jong-Seo Chai;Jongchul Lee;Hoseung Song
    • Nuclear Engineering and Technology
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    • 제55권8호
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    • pp.3114-3120
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    • 2023
  • A high-accuracy magnetic field measurement device based on a cyclotron is being developed for accelerator mass spectrometry (AMS). In this study, a magnetic field measurement device consisting of a Hall probe sensor, piezo-motor, and step motor was developed to measure the magnetic field of the AMS cyclotron magnet. The Hall probe sensor was calibrated to achieve positional accuracy by using polar coordinates. The measurement results between the ratchet gear and piezo-motor, which are the instruments used for driving the measurement device, were analyzed. The measurement result of the device with a piezo-motor exhibits a difference of 5 Gauss (0.04%) as compared with the simulation result.

경사진 Field Plate 구조 GaAs 쇼트키 다이오드 (GaAs Schottky Diode with Taper Field Plate)

  • 김성룡;양희윤;최연익
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 C
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    • pp.1618-1620
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    • 1997
  • A GaAs schottky diode with taper field plate is proposed to increase breakdown voltage. Breakdown voltage is calculated by device simulator MEDICI. The GaAs schottky diode with taper gate which has $5.7^{\circ}$ taper angle have shown 45% increase in the breakdown voltage compared with conventional field plate GaAs schottky diode.

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Fabrication and Characteristics of Superconducting Magnetometer

  • Lee, Sang-Heon
    • Transactions on Electrical and Electronic Materials
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    • 제6권2호
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    • pp.70-72
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    • 2005
  • The relation between electrical properties of YBaCuO ceramic superconductor and externally applied magnetic field was studied. Electrical characteristics of the superconductor with trapped magnetic fluxes are extremely sensitive to the external magnetic field and show the different responses which depend on the direction of the magnetic field. Considering these properties of the superconductor with trapped magnetic fluxes, a magnetic sensor is fabricated. This sensor is able to detect simultaneously both the intensity and the direction of the magnetic field. The sensitivity of the sensor is less than 10$^{-4} T.

오손물질에 따른 고분자 장간애자의 표면 전계분포 (Electric field distribution on the surface of polymer post insulator according to state of water drops)

  • 장동욱;한문섭;김형철
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.1418-1419
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    • 2007
  • In order to check the electric field distribution of polymer line post insulator, we performed electric field simulation according to state of water drops. Sea water is used to the contaminant. Electric field analysis is performed with change of contact angle, number and distance of water drops.

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Characterization of Lateral Type Field Emitters with Carbon-Based Surface Layer

  • Lee, Myoung-Bok;Lee, Jae-Hoon;Kwon, Ki-Rock;Lee, Hyung-Ju;Hahm, Sung-Ho;Lee, Jong-Hyun;Lee, Jung-Hee;Choi, Kyu-Man
    • Journal of Information Display
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    • 제2권3호
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    • pp.60-65
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    • 2001
  • Lateral type poly-silicon field emitters were fabricated by utilizing the LOCOS (Local Oxidation of Silicon) process. For the implementation 'of an ideal field emission device with quasi-zero tunneling barrier, a new and fundamental approach has used conducted by introducing an intelligent carbon-based thin layer on the cathode tip surface via a field-assisted self-aligning of carbon (FASAC) process. Fundamental lowering of the turn-on field for the electron emission was feasible through the control of both the tip shape and surface barrier height.

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초전도 자기 검출소자 (Magnetic Field Sensor by Using Superconductor)

  • 이상헌
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 하계학술대회 논문집
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    • pp.86-88
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    • 2002
  • The relationship between electrical properties of superconductor and externally allied magnetic field was studied to develop a magnetic field polarity sensor. The behavior was related to the magnetic flux trapped in the superconductor, which penetrates through the material by the external magnetic field. Electrical characteristics of the superconductor with trapped magnetic flux were extremely sensitive ta the external magnetic field and showed different responses depending on the direction of the magnetic field. Considering the observed properties of the superconductor with trapped magnetic flux, a magnetic sensor was fabricated to detect simultaneously both the intensity and the direction of the magnetic field.

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Effect of a Magnetic Field on Electrical Conductivity of a Partially Ionized Plasma

  • Yun, Hong-Sik
    • 천문학회지
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    • 제8권1호
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    • pp.29-34
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    • 1975
  • Solar electrical conductivity has been calculated, making use of Yun and Wyller's formulation. The computed results arc presented in a tabulated form as functions of temperature and pressure for given magnetic field strengths. The results of the calculation show that the magnetic field does not play any important role in characterizing the electrical conductivity of the ionized gas when the gas pressure is relatively high (e.g., $P{\geq}10^4\;dynes/cm^2$). However, when the gas pressure is low (e.g., $P{\leq}10\;dynes/cm^2$), the magnetic field becomes very effective even if its field strength is quite small (e.g., $B{\leq}0.01$ gauss). It is also found that, except for lower temperature region (e.g., $T{\leq}10^{4^{\circ}}K$), there is a certain linear relationship in a log- log graph between the pressure and the critical magnetic field strength, which is defined as a field strength capable of reducing the non-magnetic component of the electrical conductivity by 20%.

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