• 제목/요약/키워드: external field

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방전프라즈마내 자계에 의한 마이크로파 반사특성 (A Study on the Microwave Reflection of Plasma in a Magnetic Field)

  • 김봉열;김정기
    • 대한전자공학회논문지
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    • 제6권1호
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    • pp.12-18
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    • 1969
  • 도피관내 프라즈마상태를 발생시켜 외부자계를 마이크로파 전계에 수평 및 수직되게 가하여 그 때 일어나는 마이크로파 반사전력 및 투과전계를 측정하였다. 마이크로파 전계와 외부자계가 수평인 경우 외부자속밀도가 증가할 수록 감쇠만 일어났으나 서로 수직인 경우에는 3120가우스에서 반사전력이 최대로 되어 공진현상이 일어났다.

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고온초전도 선재의 접합 및 인덱스손실 평가 (Estimation of joint and index dissipation in HTS tape)

  • 김정호;임준형;장석헌;김규태;주진호;최세용;나완수;강형구;고태국
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2003년도 추계학술대회 논문집
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    • pp.59-62
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    • 2003
  • We fabricated two HTS closed coils by using resistive-joint method and the joint resistance of the coil was estimated by field decay technique at 77 K. In addition, we used the Runge-kutta method for the numerical analysis to estimate the decay properties. The joint resistances were evaluated as a function of critical current of HTS closed coil and external field strength of excitation coil. It was observed that joint resistance was independent of critical current and external field strength. It was estimated that joint resistance was 8.0$\times$10$^{-9}$ $\Omega$ to 11.9$\times$10$^{-9}$ $\Omega$ for coils of contact length for 7 cm.

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Capping Material & External Field Intensity에 따른 자기 저항 특성 연구 (Magnetic Properties of MTJ by Capping Material & External Field Intensity)

  • 이계남;장인우;박영진;박상용;이재형;전경인;신경호
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2002년도 동계연구발표회 논문개요집
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    • pp.50-51
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    • 2002
  • 최근 실온에서 약 40% 이상의 높은 자기저항(magnetoresistance, MR)을 나타내는 자기 터널 접합(magnetic tunnel junction, MTJ)이 보고되면서 비휘발성 자기메모리로의 응용을 눈앞에 두고 있다.[1]. 이에 본 실험에서는 Substrate / Ta (base electrode) / NiFe / PtMn (AF pinning layer) / CoFe (pinned) / Ru / CoFe (fixed) / Al-O/ CoFe (free) / NiFe (free) / Ta & Ru (Capping Layer)과 같은 MTJ 증착 구조를 사용하여, MTJ의 보다 향상된 특성을 확보하기 위한 노력으로서 Al-O 두께, 어닐링 조건(Field Intensity & Sequence)변화 등을 시도하였다. (중략)

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YBCO CC와 BSCCO Tape의 적층에 따른 자화손실 특성비교 (Comparison Magnetization Losses of the multi-stacked YBCO Coated conductor and the BSCCO tapes)

  • 임형우;이희준;차귀수;이지광
    • 한국초전도ㆍ저온공학회논문지
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    • 제7권3호
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    • pp.13-16
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    • 2005
  • Multi-stacked HTS tapes are needed to conduct large current in the power application. In this paper magnetization losses of the multi-stacked YBCO coated conductor and the BSCCO tape have been measured and compared. Magnetization losses of single tape, 2-stacked, 3-stacked and 4-stacked HTS tapes have been presented in this paper. Multi-stacked tapes have been fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various stacked of external magnetic field to consider the anisotropic characteristics of HTS tapes. Test results show that loss density per unit volume decreased for both YBCO coated conductors and BSCCO tapes when the stacking number of tapes is increased. As the external magnetic field decreased, the ratio of decrement has risen because the full penetration magnetic field(Bp) of the multi-stacked tape is larger than that of the single tape.

고분자내 케리아의 트랍핑 현상에 관한 연구 (The Study on Trapping Phenomena of Charge Carrier in Polymer)

  • 이덕출
    • 전기의세계
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    • 제26권4호
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    • pp.68-72
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    • 1977
  • The main purpose of this paper is to study on the nature of the traps in polymer. The polyethlene is typical of polymer material as to be selected for a sample. The current I$_{th}$ are obtained with an small external bias voltage from high density polyethylene which have been treated by the high-field application. Two peaks, P$_{1}$ and P$_{2}$ with maxima near 85.deg. C, respectively, appeared on the current I$_{th}$ spectrum. From the results of experiment, It is clear that The current I$_{th}$ arises from the drift, under the external field, of carriers released from the trap sites by the heating and the trap is surrounded by a potential barrier and trapping proceeds during the high-field treatment. The obtained results can suggest that polyethylene contains trap sites which have an important role in the electrical conduction and breakdown of polymeric materials.rials.

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Co계 아몰퍼스리본을 이용하여 제작한 마안더패턴의 고주파 임피던스특성 (High Frequency Impedance of Meander Pattern Fabricated by Co-base Amorphous Ribbon)

  • 신광호;박경일;사공건;송재연;김영학
    • 한국자기학회지
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    • 제13권4호
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    • pp.160-164
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    • 2003
  • 연자성이 우수한 Co계 아몰퍼스리본을 리소그래피와 에칭을 통하여 미안더타입(meande, type)의 미소패턴으로 가공하고 표피효과가 현저하게 나타나는 300 KHz∼l ㎓의 주파수영역에서 고주파임피던스, 저항, 인덕턴스에 미치는 외부자기장의 영향을 조사하였다. 제작한 아몰퍼스리본의 미안더패턴은 자기장중 열처리를 통하여 폭방향으로 자기용이축이 유도되어 있었으며 패턴의 길이방향으로 인가된 외부자기장에 대하여 민감한 임피던스의 변화를 나타내었다. 임피던스는 약 13 Oe부근의 인가자기장에서 최대값을 나타내었으며 50 MHz에서 11 Oe의 인가 자기장에 대하여 약 210%의 임피던스 변화율을 나타내었다.

자장감쇠법을 이용한 $(Bi,Pb)_2Sr_2Ca_2Cu_3O_x$/Ag 초전도선재의 접합저항 측정 (Measurement of Joint Resistance of $(Bi,Pb)_2Sr_2Ca_2Cu_3O_x$/Ag Superconducting Tape by Field decay Technique)

  • 김정호;이승묵;주진호
    • Progress in Superconductivity
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    • 제14권1호
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    • pp.1-10
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    • 2012
  • We fabricated a closed coils by using resistive-joint method and the joint resistance of the coils were estimated by field decay technique in liquid nitrogen. We used the Runge-kutta method for the numerical analysis to calculate the decay properties. The closed coil was wound by $(Bi,Pb)_2Sr_2Ca_2Cu_3O_x$/Ag tape. Both ends the tape were overlapped and soldered to each other. The current was induced in a closed coils by external magnetic flux density. Its decay characteristic was observed by means of measuring the magnetic flux density generated by induced current at the center of the closed coil with hall sensor. The joint resistance was calculated as the ratio of the inductance of the loop to the time constants. The joint resistances were evaluated as a function of critical current of loop, contact length, sweep time, and external magnetic flux density in a contact length of 7 cm. It was observed that joint resistance was dependent on contact length of a closed coil, but independent of critical current, sweep time, and external magnetic flux density. The joint resistance was measured to be higher for a standard four-probe method, compared with that for the field decay technique. This implies that noise of measurement in a standard four-probe method is larger than that of field decay technique. It was estimated that joint resistance was $8.0{\times}10^{-9}{\Omega}$ to $11.4{\times}10^{-9}{\Omega}$ for coils of contact length for 7 cm. It was found that 40Pb/60Sn solder are unsuitable for persistent mode.

CLT 건축물의 외벽 및 지붕 구조체 레이어 구성 유형 분석 (Analysis of the Types of External Wall and Roof Structure Layer Composition of CLT Building)

  • 유동완;이태구
    • 한국농촌건축학회논문집
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    • 제22권4호
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    • pp.71-78
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    • 2020
  • Today, the whole world is going through a big chaos due to the COVID-19, but paradoxically, the emergence of COVID-19 has been leading to the need for sustainable development, such as Green New Deal that can improve global warming and carbon emissions, and the need for sustainable architecture is growing bigger and bigger in the architectural field as well. The level of CLT buildings in Korea is at a very rudimentary stage, while CLT buildings remedying existing wooden buildings are getting the spotlight among European countries for sustainable architecture. This study was conducted to categorize structure layer compositions of overseas CLT buildings and analyze architectural techniques and materials applied by collecting and analyzing information about CLT structure layer compositions of overseas CLT building-related institutions, companies and cases. When classifying structure layer compositions of foreign CLT buildings depending on the roles of layers. it was revealed that exterior wall structure layers were combined and organized within a sequence of external finishing, ventilation, waterproof, board, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing, sloped roof structure layers were external finishing, ventilation, waterproof, board, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing, flat roof structure layers were external finishing, ventilation, waterproof, planking wood, external insulation, waterproof, external insulation, airtightness, structure, airtightness, interior insulation, interior finishing.

실증 적용을 통한 외부 전동블라인드의 성능 평가 및 개선 방안 (Evaluation and improvement of external electric blinds through field application)

  • 강민우;이희동;오양기
    • 한국음향학회지
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    • 제42권3호
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    • pp.181-188
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    • 2023
  • 일반적인 거주 공간에서 창호는 외부소음에 직접적으로 노출된다. 외부소음을 가장 효과적으로 저감할 수 있는 방법은 내부가 아닌 외부에서 바로 소음을 차단하는 방법이다. 태양 빛 차단을 위한 외부 블라인드는 다양하게 제품화되어 있지만, 우리나라에서는 아직 적극적으로 활용되지 못하고 있다. 앞선 연구에서는 차광용으로 제작된 외부 전동블라인드의 차음성능을 검증하기 위해 공인 실험실에서 실험하였다. 그 결과 일반창호 저감 성능 대비 6 dBA의 추가 차음성능을 검증하였다. 이 연구에서는 외부 전동블라인드의 차음성능을 실제 거주 공간 창호에 실증 적용하여 저감성능을 확인하고자 하였으며, 효과적인 소음저감 성능 추가확보를 위해 개선방안을 모색하고자 하였다. 실험결과, 외부 전동블라인드 자체의 저감 성능은 기본 창호 대비 1 dBA ~ 3 dBA 수준으로 미미했다. 하지만 블라인드 슬릿 사이의 틈새 충진을 통해 2 dBA 수준의 추가 저감성능을 확인하였다.

RELATIONSHIP BETWEEN STATIC AND DYNAMIC MAGNETORESISTANCE BEHAVIOR OF METALLIC ARTIFICIAL SUPERLATTICES

  • Song, Yong-Jin;Joo, Seung-Ki
    • 한국자기학회지
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    • 제5권5호
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    • pp.567-569
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    • 1995
  • By using the ac field source which can change the applied field magnitude, frequency and dc offset field, the dynamic magnetoresistance characteristics of permalloy based multilayers which have different R-H(resistance-magnetic field) curves were monitored and compared with static magnetoresistance curves that were measured with electromagnet of VSM. Output of each sample according to the external field strength was identified and optimum bias position could be obtained.

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