• 제목/요약/키워드: barrier well

검색결과 760건 처리시간 0.031초

Multi Quantum Well 구조를 이용한 Red에서 Green으로의 energy transfer mechanism의 이해

  • 김강훈;박원혁
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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    • pp.145-145
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    • 2015
  • 처음 유기물의 인광 발견 이후 Host-dopant 시스템을 이용하여 Emission layer(EML)을 Co-deopsition 하는 방법으로 주로 인광 유기 발광 다이오드를 제작 하였다. [1] co-deposition을 이용해 만든 유기 발광 다이오드에 많은 장점이 있지만, 반대로 소자를 제작하는데 있어서는 많은 문제점을 가지고 있다. [2-4] 이러한 문제점을 개선하기 위하여 co-deposition 대신 non-doped Multi Quantum Well(MQW) 구조를 사용하여 doping 하지 않는 방법을 이용하는 논문들이 보고 되고 있다. Hole, electron, exciton이 MQW 구조를 지나면서, dopant well 안에 갇히게 되고, 그 안에서 다른 layer 간에 energy transfer와, hole-electron leakage가 줄어 들어, 더 효율적인 유기 발광 다이오드를 만들 수 있게 된다. [5-7] 이 연구에서는 CBP를 Potential Barrier로 사용하고, Ir(ppy)3 (Green dopant), Ir(btp)2 (Red dopant) 를 각각 Potential Well로 사용하였고, 두께는 CBP 9nm, dopant 1nm로 하였다. 이러한 소자를 만들고 dopant를 3개의 well에 적당히 배치하여, 각 well에서의 실험적인 발광 량 과, EML 안에서의 발광 mechanism 그리고 각 potential barrier를 줄여가며 dexter, forster에 의한 energy transfer에 대하여 알 수 있었다.

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백호탕 추출물의 지방장벽 손상 개선을 통한 상피 내 Th2 분화 조절 효과 (The Effects of Baekho-tang Extracts on Regulating Th2 Differentiation through Improving Skin Fat Barrier Damage)

  • 안상현;김기봉;정아람
    • 대한한방소아과학회지
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    • 제35권4호
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    • pp.156-166
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    • 2021
  • Objectives The purpose of this study is to confirm the regulate effect of T helper (Th) 2 differentiation that Baekho-tang extract may produce to improves skin lipid barrier damages. Methods Four-weeks-old NC/Nga mice were divided into four groups: control group (Ctrl, n=10), lipid barrier eliminated group (LBE, n=10), Dexamethasone treatment after lipid barrier elimination group (DxT, n=10), and Baekho-tang extract treatment group after lipid barrier elimination group (BHTT, n=10). Baeko-tang extract was administered for 3 days after removal of the skin fat barrier in BHTT group. Then, we identified changes in external symptoms of the skin, factors affecting skin barrier such as potential of hydrogen (pH), filaggrin (FLG), transepidermal water loss (TEWL) and Th2 differentiation factors like Interleukin (IL)-4, Kallikrein Related Peptidase 7 (KLK7) and protease activated receptor 2 (PAR-2) through our immunohistochemistry. Results After lipid barrier elimination, the reduction of morphological skin inflammations was less in BHTT group than in LBE group and DxT group. Also, pH and TEWL were significantly decreased with BHTT group. However, FLG was significantly increased in BHTT group compared to LBE, DxT, and Ctrl group. All kinds of Th2 differentiation factors (IL-4, KLK7 and PAR-2) were also decreased in BHTT compared to the LBE and DxT. Conclusions As a result of this study, BHT administration decreased pH, TEWL, and increased FLG, thus participating in recovering damaged skin barrier. Since Th2 differentiation factors were decreased as well, BHT's regulatory effect in sequential immune reactions may be a possible explanation of how it enhances recovery of the damaged lipid barrier.

Analysis of Schottky Barrier Height in Small Contacts Using a Thermionic-Field Emission Model

  • Jang, Moon-Gyu;Lee, Jung-Hwan
    • ETRI Journal
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    • 제24권6호
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    • pp.455-461
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    • 2002
  • This paper reports on estimating the Schottky barrier height of small contacts using a thermionic-field emission model. Our results indicate that the logarithmic plot of the current as a function of bias voltage across the Schottky diode gives a linear relationship, while the plot as a function of the total applied voltage across a metal-silicon contact gives a parabolic relationship. The Schottky barrier height is extracted from the slope of the linear line resulting from the logarithmic plot of current versus bias voltage across the Schottky diode. The result reveals that the barrier height decreases from 0.6 eV to 0.49 eV when the thickness of the barrier metal is increased from 500 ${\AA}$ to 900 ${\AA}$. The extracted impurity concentration at the contact interface changes slightly with different Ti thicknesses with its maximum value at about $2.9{\times}10^{20}\;cm^{-3}$, which agrees well with the results from secondary ion mass spectroscopy (SIMS) measurements.

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의료방사선 차폐 고무시트의 제작과 성능 비교 (Comparison on the Performance Medical Radiation Shielding Made of Rubber Sheet)

  • 김선칠
    • 대한디지털의료영상학회논문지
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    • 제12권1호
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    • pp.15-18
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    • 2010
  • Main component of radiography barrier aprons is lead. To manufacture a lead-free barrier sheath, barium sulfate and organic iodine-based chemicals should be mixed with rubber. Barrier capacity was tested in the medical field. To improve adaptation of rubber with the mixture, raw materials went through milling, agitation, and extruding processes. Three sheaths were manufactured with 30%, 80%, and 120% sulfate barium, respectively. This study found 10% lower barrier capacity of lead-free barrier than the traditional lead-containing rubber sheath. Problems, however, were confronted during the agitation and extruding processes. Mixing with rubber was a technically demanding job. Inconsistent depth, problems with thermal processing and dissipation were encountered as well.

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방음벽 안전을 위한 기준 조사 및 분석 (Investigation and Analysis of Regulations for the Safety of the Noise Barrier)

  • 허영;김흥식
    • 한국소음진동공학회논문집
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    • 제13권9호
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    • pp.730-734
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    • 2003
  • For the noise reduction measures in a construction field or near the traffic line receiver is often the most economic measure in order to exclude the propagated sound. The dimension of the barrier is decided by the noise and construction design, and the constructive quality of a soundproof panel shall be secured in accordance with KS F4770 to guarantee the safety of sound barriers. In this paper the problems included in the KS F4770-1 that is the regulation for the metallic sound barrier of the absorption type are identified and it is suggested what to be corrected or improved. Through a series of the analyses, conclusions were reached that it is required to improve test methods in KS F4770-1 as well as to break down test loads for building more cost-effective sound barrier.

방음벽 안전을 위한 기준 조사 및 분석 (Investigation and Analysis of Regulations for the Safety of the Sound Barrier)

  • 허영;김홍식
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.219-223
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    • 2003
  • For the noise reduction measures in a construction field or near the traffic line receiver is often the most economic measure in order to exclude the propagated sound. The dimension of the barrier is decided by the noise and construction design, and the constructive quality of a soundproof panel shall be secured in accordance with KS F4770 to guarantee the safety of sound barriers. In this paper the problems included in the KS F4770-1 that is the regulation for the metallic sound barrier of the absorption type are identified and it is suggested what to be corrected or improved. Through a series of the analyses, conclusions were reached that it is required to improve test methods in KS F4770-1 as well as to break down test loads for building more cost-effective sound barrier.

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피부장벽회복에 영향을 미치는 인자에 관한 연구 (The study on the factors which improve skin barrier recovery)

  • 차재훈;김윤범
    • 한방안이비인후피부과학회지
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    • 제21권2호
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    • pp.39-45
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    • 2008
  • Objective : Skin barrier protects skin against harmful environment. Its function includes antimicrobial barrier as well as physical barrier. But there are few studies about the factors which improve skin barrier recovery after injury. The aim of this study is to investigate the factors which improve skin barrier recovery. Method : Nine hairless mice was anesthetized by inhalation and we tape stripped them. We used thermometer to know temperature one day ago, before anesthesia, before tape stripping, and after tape stripping. Vapometer was used to know transepidermal water loss before tape stripping, after tape stripping. And we used doppler flowmeter to measure blood flow before tape stripping, after tape stripping. Result : After analyzed data, we concluded that temperature was lower after anesthesia than before anesthesia and after tape stripping than before tape stripping. We could know that transepidermal water loss was lower after tape stripping than before tape stripping and more blood flowed after tape stripping. Conclusion : In our study, it was observed that temperature, transepidermal water loss, blood flow changed after tape stripping. But we thought lowered temperature was pathologic situation, more blood flow was to recover after injury. In traditional korean medicine, cold(寒) and imbalance of blood flow(血行) don't only make many skin diseases, but cold(寒) also obstructs blood flow. So we need to study how to warm cold(寒) and improve blood flow.

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Width Control in the Photo patterning of PDP Barrier Ribs

  • Kim, Dong-Ju;Kim, Soon-Hak;Hur, Young-June;Kim, Duck-Gon;Lee, Sam-Jong;Jung, Sang-Kwon;Kim, Myeug-Chan;Park, Lee-Soon
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.910-912
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    • 2006
  • Barrier ribs in plasma display panels (PDPs) function to maintain the discharge space between the glass plates as well as to prevent optical cross-talking. The barrier ribs currently employed are typically $300{\mu}m$ pitch, $110{\sim}120{\mu}m$ in height, with upper and lower widths of $50{\mu}m$ and $80{\mu}m$, respectively. It has been reported that barrier ribs can be fabricated by screen-printing, sand blasting, etching and photolithographic processes. In this study, photosensitive barrier rib pastes were formulated and systematically evaluated in terms of photolithographic process variables such as printing, drying, UV exposure, development and sintering. It was found that the use of UV absorbent, polymerization inhibitor and surfactant were very effective in controlling the width uniformity of barrier ribs in the photolithographic method of barrier rib patterning.

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고체유전체의 장벽과 도전성 파티클이 섬락전압에 미치는 영향 (Influence of Flash-over Voltage on Conductive Particle-Initiated and Solid Dielectric Barrier)

  • 이용길;김동의;이세헌;김재호;김정달
    • 한국조명전기설비학회지:조명전기설비
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    • 제8권3호
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    • pp.54-63
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    • 1994
  • 본 연구에서는 판상스페이서 위에 침전극을 고정하고 gap간격 40[mm]에 평판전극을 설치한 gap 간에 10[mm]간격으로 나누어 각 구간내에 스페이서와 같은 재질의 Barrier를 설치하고 파티클을 두었을 때 AC 및 정극성 DC 전압에서의 방전로와 FOV에 대해 연구한 결과 다음과 같은 결론을 얻엇다. 1) Barrier가 고전위측에 위치한 경우와 파티클이 Barrier뒤에 은폐된 경우가 FOV가 높다. 2) 침전극 선단에 파티클 위치할 때 심한 FOV의 감소가 있다. 3) 파티클이 전극간에 게재되면 방전로는 파티클을 경유하므로 FOV는 감소한다.

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사백산 추출물의 지방장벽 생성을 통한 Th2 분화 조절 (Th2 Differentiation Control through Formation of Skin Fat Barrier of Sabaek-san extract)

  • 안상현;정아람;김기봉
    • 대한한방소아과학회지
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    • 제36권1호
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    • pp.57-64
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    • 2022
  • Objectives The purpose of this study is to confirm the regulate effect of T helper (Th) 2 differentiation that Sabaek-san extract may produce to improves skin lipid barrier damage. Methods Four-weeks-old NC/Nga mice were divided into four groups: control group (Ctrl, n=10), lipid barrier eliminated group (LBE, n=10), Dexamethasone treatment after lipid barrier elimination group (DXT, n=10), and Sabaek-san extract treatment group after lipid barrier elimination (SBT, n=10). Sabaek-san extract was administered for 3 d after removal of the skin fat barrier in SBT group. Then, we identified changes in external symptoms of the skin, factors affecting skin barrier such as potential of hydrogen (pH), filaggrin, transepidermal water loss (TEWL) and Th2 differentiation factors like Interleukin (IL)-4, Kallikrein Related Peptidase 7 (KLK7), and protease activated receptor 2 (PAR-2) through our immunohistochemistry. Results After lipid barrier elimination, the reduction of morphological skin inflammations was less in SBT group than in LBE and DXT group. Also, pH and TEWL were significantly decreased with SBT group. However, filaggrin was significantly increased in SBT group compared to LBE, DXT, and Ctrl group. All kinds of Th2 differentiation factors (IL-4, KLK7 and PAR-2) were also decreased in SBT compared to the LBE and DXT. Conclusions As a result of this study, SBT administration decreased pH, TEWL, and increased filaggrin, thus participating in recovering damaged skin barrier. Since Th2 differentiation factors were decreased as well, SBT's regulatory effect in sequential immune reactions may be a possible explanation of how it enhances recovery of the damaged lipid barrier.