• 제목/요약/키워드: Alternating Current

검색결과 391건 처리시간 0.028초

진동정렬 EPD YBCO 후막테이프의 초전도 특성 개선 (Superconducting Properties of Shaky-aligned EPD Thick Film of YBCO Tape)

  • 소대화;조용준;박성범;전용우
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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    • pp.111-114
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    • 2003
  • In order to improve the surface uniformity and the conduction properties of the fabricated YBCO thick films, a system that applies alternating field vertically to the EPD field has been developed for the first time and applied to the electrophoretic deposition process. The applied alternating electric field caused a force to be exerted on each YBCO particle and resulted in a shaking of the particle in the direction of applied electric field, accomplishing a uniform particle orientation. The usual commercial electrical power was used for the vertically applied alternating voltage and the induced electric field was 25-120 V/cm at 60Hz. The thick film fabricated by the method developed in this paper showed better surface uniformity without crack and porosity and improved film characteristics such as critical temperature ($T_{c,zero}$ : 90 K) and critical current density ($2354\;A/cm^2$). Therefore, it is expected that the shaky-aligned electrophoretic deposition method can be used to fabricate superconductor films through a simpler process and at less expense.

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제주도 발전 전략의 교호적 변화 (Alternating Development Strategies in Jeiu Island, Korea)

  • 권상철
    • 대한지리학회지
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    • 제43권2호
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    • pp.171-187
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    • 2008
  • 섬지역은 작은 규모와 고립된 특성으로 인해 취약한 경제기반으로 특징지워 진다. 여기에 오랜 고립에 따른 독특한 문화와 자연경관은 관광 중심의 개발로 이어지게 된다. 제주도도 세계 다른 섬지역과 마찬가지로 이러한 개발을 경험하는데, 이러한 지역변화는 섬지역의 취약성에 초점을 맞추어 대다수 중앙정부 주도로 이루어진 것으로 지역에서의 대응은 축소되어 이해되고 있다. 본 논문에서는 섬지역 주민들은 자신들의 취약성에 기초해 중앙정부의 정책을 수용하면서 자신들에게 유리하게 변용하는 교호적 전략을 구사해 왔다고 이해한다. 교호적 전략은 3가지 측면에 반영되고 있는데, 첫째 제주도는 국회의원 선거에서 무소속 후보를 선호해 오다 근래에는 여당 후보 그리고 야당 후보를 교대로 선출하는 모습을 보여준다. 둘째 중앙정부의 지역개발정책에 대한 반대운동을 통해 주민생활의 향상과 개선을 반영하는 수정을 요구하여 왔다. 셋째 중앙정부 주도의 개발정책이 효율성을 극대화하는 거점중심의 관광지 개발을 지역의 균형발전 요구로 대응하며 제주전역으로 개발을 확대시켰다. 이러한 개발 과정과 결과는 중앙정부의 관광개발 정책을 견제, 섬으로서의 제주지역의 취약함에서 찾아낸 교호적 전략의 결과로 볼 수 있을 것이다.

A Critical Note on the Electric Field in Direct and Alternating Current and Its Consciousness

  • Oh, Hung-Kuk
    • 한국감성과학회:학술대회논문집
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    • 한국감성과학회 2000년도 추계학술대회 논문집
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    • pp.98-104
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    • 2000
  • The conventional model did not take momentum conservation into consideration when the electron absorbs and emits the photons. II-ray provides momentum conservations on any directions of the entering photons, and also the electrons have radial momentum conservations and fully elastic bouncing between two atoms, in the new atom model. Conventional atom model must be criticized on the following four points. (1) Natural motions between positive and negative entities are not circular motions but linear going and returning ones, for examples sexual motion, tidal motion, day and night etc. Because the radius of hydrogen atom's electron orbit is the order of 10$^{-11}$ m and the radia of the nucleons in the nucleus are the order of 10$^{-14}$ m and then the converging $\pi$-gamma rays to the nucleus have so great circular momentum, the electron can not have a circular motion. We can say without doubt that any elementary mass particle can have only linear motion, because of the $\pi$-rays'hindrances, nearthenucleus. (2) Potential energy generation was neglected when electron changes its orbit from outer one to inner one. The h v is the kinetic energy of the photo-electron. The total energy difference between orbits comprises kinetic and potential energies. (3) The structure of the space must be taken into consideration because the properties of the electron do not change during the transition from outer orbit to inner one even though it produces photon. (4) Total energy conservation law applies to the energy flow between mind and matter because we daily experiences a interconnection between mind and body. Conventional Concept of Electric Field must be extended in the case of the direct and alternating current. Conventional concept is based on coulomb's force while the electric potential in the direct and alternating current is from Gibb's free energy. And also conventional concept has not any consciousness with human being but the latters has a conscious sensibility. The cell emf is from the kinetic energy of the open $\pi$-rays flow through the conducting wire. The electric potential in alternating current is from that the trans-orbital moving of the induced change of magnetic field in the wire produces flows of open $\pi$-rays, which push the rotating electrons on the orbital and then make the current flow. Human consciousness can induce a resonance with the sensibility of the open $\pi$-rays in the electric measuring equipment. Specially treated acupunctures with Nasucon is for sending an acupunctural effect from one place to another via space by someone's will power.

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신체 성분 분석을 위한 다 주파수 생체전기 임피던스 분석 시스템 구현 (Implementation of Multiple Frequency Bioelectrical Impedance Analysis System for Body Composition Analysis)

  • 김성철;조병남;이석원
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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    • pp.331-333
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    • 2004
  • In this study, we implement the multiple frequency bioelectrical impedance analysis system for body composition analysis. Overall system consists of : 1) conductivity electrodes to contact with hands and foots, 2) multiple frequency alternating current signal generator for generating 5, 50, 250kHz frequency and 800uA contained alternating current signal, 3) voltage signal detector, 4) phase signal detector, 5) key-pad to input individual information, 6) micro controller for data processing, 7) LCD for processed data to display, 8) system power, We explain the architecture of the system and required theory to implement the system. Finally, experimental results are illustrated to show the performance of the system.

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Development of New Cancer Therapy and Its Physics

  • Oh, Hung-Kuk;Jeong, Jin-Ha
    • 한국감성과학회:학술대회논문집
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    • 한국감성과학회 2001년도 춘계학술대회 논문집
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    • pp.147-155
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    • 2001
  • Nasucon lamp and Russian ones, which are coated with some special materials on the glass bulb, gave good clinical results for a cancer therapy. They are experimentally studied with Automatic Bioelectric Response Recorder on the six placements of the electrodes (two feet, two hands and two foreheads). They reduced the current rather than the control (natural) state. However infrared lamp and Chinese God light did not reduced the value current. Hemoglobin in blood. Brown gas, Ti$_3$SiC$_2$ and Nasucon have planar crystallizing $\pi$-bonding bonding layer and covalent bonding one in sequence commonly and thus the alternating magnetic fields are protected. Nasucon lamp and Russian ones utilized electric bulbs in order to generate alternating magnetic fields and to produce absorbing force.

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Spatiotemporal Behavior of the Excited Xe Atom Density in the $1s_5$ Metastable State According to the Hoof-type Electrode Structure in an Alternating-current Plasma Display Pane

  • Kim, Yong-Hee;Hong, Young-June;Choi, Joon-Ho;Cho, Byeong-Seong;Uhm, Han-Sub;Choi, Eun-Ha
    • Journal of Information Display
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    • 제11권4호
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    • pp.149-153
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    • 2010
  • To improve the luminescence characteristics of high-efficiency alternating-current plasma display panels (AC-PDPs), we developed a new hoof-type electrode structure, and we studied the spatiotemporal behavior of the density of the excited Xenon atom in the $1s_5$ metastable state via laser absorption spectroscopy. Using this structure, the maximum density of the excited Xenon atom per cell was improved by 2.4 times that when the conventional electrode structure was used.

교류 구동형 박막 전계 발광 소자용 원추형 Si micro-tip 반사체 어래이의 제작 (Fabrication of Cone-shaped Si Micro-tip Reflector Array for Alternating Current Thin Film Electroluminescent Device Application)

  • 주병권;이윤희;오명환
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제48권9호
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    • pp.662-664
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    • 1999
  • We fabricated AC-TFEL device having cone-shaped Si micro-tip reflector array based on the process which have been conventionally employed for the Si-tip field emitter array in FED system. As a result, the AC-TFEL device having a new geometrical structure could generate well concentrated visible white-light from 3600 reflectors/pixel under bipolar pulse excitation mode only by edge-emission mechanism.

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$Ca(OH)_2$ 수용액에서 Zn과 Zn-Fe 합금의 부식 (Corrosion of Zn and Zn-Fe alloys in $Ca(OH)_2$ Solutions)

  • 이수선;강성군
    • 한국표면공학회지
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    • 제19권4호
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    • pp.133-139
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    • 1986
  • The effects of alternating voltage, $Cl^-$ ion and pH on the corrosion of Zn and Zn-Fe alloys have been investigated by using electrochemical techniques in $Ca(OH)_2$ solutions. The passive film $Zn(OH)_2$ was initially formed on the Zn surface and gradually transformed to $Ca(Zn(OH)_3)_2{\cdot}2H_2O$, which was identified with the X-ray diffraction method, SEM micrograph and EPMA. The passivity current increased with increasing alternating voltage and decrease AC frequency. ${\xi}$ phase in Zn-Fe alloys reduced the effects of AC. The effect of $Cl^-$ ion on the passivity current of Zn was similar to the AC effect, resulting in pits on Zn. It was also found that the passive region of Zn decreased rapidly below pH 10.3 of the solution.

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Electrochemical Parameters with unusual Alternating Current Phase-Angles

  • Rashwan Farouk;Mohran Hossnia
    • 전기화학회지
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    • 제7권2호
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    • pp.80-82
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    • 2004
  • The a.c. technique is employed to evaluate electrochemical characteristics of Naphthalie-1,4,5,8-tetracarboxylic acid bisanilide (NTB). The measurements were carried out in dry and pure propionitrle (PCN) and acetonitrile(CAN) at the hanging mercury drop electrode [HMDE). An A.C. phase sensitive detector using computer controlled lock-in amplifier was employed. Primary goal of this report, was to establish on a firm the rare behavior of the phase angle associated with a.c. polarograms of the compound. Although, not an initial goal of this study, the electron transfer rate parameters attending the electroreduction of the compound under investigation were determined. This because the results shed some light on the electrokinetics in aprotic solvent which until recently negligible data were available. Experimental Results and comparison of data obtained are reported. The good precision of the method makes it suitable for studying electrochemical data with unusual behavior at electrodes in non aqueous media.

Effect of open-core screw dislocation on axial conductivity in semiconductor crystals

  • Taira, Hisao;Sato, Motohiro
    • Advances in nano research
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    • 제1권3호
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    • pp.171-182
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    • 2013
  • The alternating current (AC) conductivity in semiconductor crystals with an open-core screw dislocation is studied in the current work. The screw dislocation in crystalline media results in an effective potential field which affects the electronic transport properties of the system. Therefore, from a technological view point, it is interesting to investigate properties of AC conductivity at frequencies of a few terahertz. To quantify the screw-induced potential effect, we calculated the AC conductivity of dislocated crystals using the Kubo formula. The conductivity showed peaks within the terahertz frequency region, where the amplitude of the AC conductivity was large enough to be measured in experiments. The measurable conductivity peaks did not arise in dislocation-free crystals threaded by a magnetic flux tube. These results imply different conductivity mechanisms in crystals with a screw dislocation than those threaded by a magnetic flux tube, despite the apparent similarity in their electronic eigenstates.