• Title/Summary/Keyword: Yook Kyoung

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Analysis of Coupling Effects in Transmission Lines Using the BLT Equation and Numerical Methods (BLT 방정식과 수치해석 기법을 이용한 전송 선로의 커플링 효과 분석)

  • Du, Jin-Kyoung;Ahn, Jae-Woon;Hwang, Sun-Mook;Yook, Jong-Gwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.1
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    • pp.99-103
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    • 2012
  • The electromagnetic topology and the BLT equation has been used as useful techniques to analyze coupling effects of huge devices. But in the case of systems including complex parts, applying the BLT equation can be difficult to manifest the complex parts with analytic solutions. To resolve this problem, a numerical method can be used to parts of the whole system in advance. In this paper, a microstrip line filter is analyzed using the BLT equation combined with numerical solutions. Consequently, achieved graphs from the BLT equation show good agreements with graphs obtained using a numerical method only.

Cross-linked Hole-Transporting Materials for Organic Light Emitting Devices (유기발광소자를 위한 가교형 정공 수송 재료)

  • Kim, Jung Kyu;Yook, Kyoung Soo
    • Prospectives of Industrial Chemistry
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    • v.22 no.3
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    • pp.1-5
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    • 2019
  • 차세대 디스플레이 소자로서 상용화된 유기발광소자(OLED)는 현재 진공기반의 증착공정을 통해서 제작되므로 제조공정 비용이 높다. 진공 증착공정을 용액공정으로 교체하면 공정 비용을 크게 절감할 수 있지만, 용액공정으로 다층 박막 구조를 형성하기 어렵다는 문제점이 있다. 다층 구조를 제작할 때 이미 형성된 하부 박막 위에 새로 형성되는 박막이 하부 박막에 영향을 주기 때문이다. 이를 해결하기 위한 방법으로서 용액 공정용 잉크 용매의 내용제성을 증가시켜 상부 박막을 코팅할 때 하부 박막이 용해되거나 손상을 입지 않도록 하는 가교형 소재를 이용한 방법이 있다. 본 원고에서는 OLED 소자를 용액공정으로 제작하기 위한 가교형 정공 수송 재료의 특징과 개발 현황에 대해 소개하고자 한다.

The Effects of Modified Constraint-Induced Movement Therapy and Bilateral Arm Training on the Upper Extremity Performance of Individuals with Chronic Hemiparetic Stroke (수정된 강제-유도운동치료와 양측성 상지훈련이 만성 뇌졸중 환자의 상지 수행 능력에 미치는 영향)

  • Yang, Sung-Hwa;Lee, Wan-Hee;Lee, Kyoung-Suk
    • The Journal of Korean Physical Therapy
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    • v.23 no.5
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    • pp.65-72
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    • 2011
  • Purpose: The intention of this study was to investigate the effects of modified constraint-induced movement therapy (mCIMT) with bilateral arm training (BAT) on the motor performance and daily activity performance of individuals with chronic hemiparetic stroke. Methods: Sixteen subjects one year after stroke participated in this study with a control group; the pretest-posttest method was used. The subjects were randomly allocated into two groups: combination of bilateral arm training and modified constraint-induced movement therapy (n=8), and modified constraint-induced movement therapy (n=8). The mCIMT group received therapy for 90 minutes in 3 sessions per week over a period of 4 weeks. The patients receiving a combination of mCIMT and BAT were treated for the same period and frequency. The results were evaluated using the Fugl-Meyer Assessment, Action Research Arm Test (ARAT), and Motor Activity Log-Amount of Use, and Quality of Movement (MAL-AOU, QOM) assessment tools. Results: The Fugl-Meyer Assessment showed that hand and wrist performance improved significantly more in the mCIMT group than in the Combination group (p<0.05). Result from the ARAT assessment showed greater scores for gross movement in the combined group than in the mCIMT group (p<0.05). The MAL-AOU showed that there was greater improvement in the combined group than in the mCIMT group (p<0.05). Conclusion: The forced use of the more affected side can be important for the enhancement of upper extremity performance for chronic hemiparetic stroke patients during their daily activities.

$CsN_3$ as an air stable and low temperature evaporable novel n doping material for high efficiency and low driving voltage in organic light-emitting diodes

  • Lee, Jun-Yeob;Yook, Kyoung-Soo;Jeon, Soon-Ok;Joo, Chul-Woong;Lee, Tae-Woo;Noh, Tae-Yong;Yang, Haa-Jin;Kang, Sung-Kee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.1319-1322
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    • 2008
  • $CsN_3$ was developed as a novel n doping material with air stability and low deposition temperature. Evaporation temperature of $CsN_3$ was similar to that of common hole injection material and it worked well as a n dopant in electron transport layer. Driving voltage was lowered and high power efficiency was obtained in green phosphorescent devices by using $CsN_3$ as a dopant in electron transport layer. It could also be used as a charge generation layer in combination with $MoO_3$. In addition, n doping mechanism study revealed that $CsN_3$ is decomposed into Cs and $N_2$ during evaporation. This is the first work reporting air stable and low temperature evaporable n dopant in organic light-emitting diodes.

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Quality Characteristics of Cookie with Burdock (Arctium lappa L.) Powder (우엉분말을 첨가한 쿠키의 품질특성)

  • Kim, Hyun-Yong;Kim, Kyoung-Hee;Yook, Hong-Sun
    • Korean journal of food and cookery science
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    • v.33 no.3
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    • pp.325-332
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    • 2017
  • Purpose: The study investigated the quality characteristics of cookies prepared 0, 10, 20 and 30% burdock (Arctium lappa L.) powder. Methods: Cookies were manufactured with 0%, 10%, 20%, and 30% wheat flour substituted for burdock powder. Results: Density of the dough showed no significant differences with increasing amount of burdock powder, whereas pH of the dough decreased with increasing burdock powder content. The pH of cookies decreased with increasing burdock powder content, whereas $^{\circ}brix$ of cookies increased with burdock powder content. The moisture contents of cookies increased with increasing burdock powder content. The spreadability of cookies decreased with increasing burdock powder content. The L-value of cookies decreased, a-value increased, and b-value decreased with increasing burdock powder content. The hardness of cookies decreased with increasing burdock powder content. Total polyphenol contents and DPPH radical scavenging activity increased with increasing burdock powder content (p<0.05). In the sensory evaluation, appearance, color, flavor, and texture were highest in the control group, whereas sweet taste and savory taste were highest in the added group. For overall acceptance of cookies, 10% burdock powder cookies showed higher values than the control and other samples. Conclusion: Results suggest that cookies manufactured with 10% burdock powder are the most optimal product.

A Spirobenzofluorene Type Phosphine Oxide Molecule as A Triplet Host and An Electron Transport Material for High Efficiency in Phosphorescent Organic Light-Emitting Diodes

  • Jang, Sang-Eok;Jeon, Soon-Ok;Yook, Kyoung-Soo;Joo, Chul-Woong;Son, Hyo-Suk;Lee, Jun-Yeob
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.767-770
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    • 2009
  • We synthesized a spirobenzofluorene type phosphine oxide (SPPO2) as a new triplet host and an universal electron transport material for phosphorescent organic light-emitting diodes(PHOLEDs). Red PHOLEDs with the SPPO2 host material showed a high quantum efficiency of 14.3 % with a current efficiency of 20.4 cd/A. In addition, the SPPO2 could be applied as an electron transport material which can be matched with any host material due to the lowest unoccupied molecular orbital of 2.4 eV. Electron injection from a cathode to the SPPO2 electron transport layer was better than common electron transport materials. In particular, the SPPO2 was effective as the electron transport material in blue PHOLEDs and the quantum efficiency was more than doubled and driving voltage was lowered by more than 3 V using the SPPO2 instead of common electron transport material.

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High efficiency deep blue and pure white phosphorescent organic light emitting diodes

  • Yook, Kyoung-Soo;Jeon, Soon-Ok;Joo, Chul-Woong;Kim, Myung-Seop;Choi, Hong-Seok;Lee, Seok-Jong;Han, Chang-Wook;Tak, Yoon-Heung;Lee, Nam-Yang;Lee, Jun-Yeob
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.486-488
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    • 2009
  • High efficiency deep blue and pure white phosphorescent organic light emitting diodes were developed using a new deep blue phosphorescent dopant, tris((3,5-difluoro-4-cyanophenyl)pyridine) iridium (FCNIr). A high quantum efficiency of 9.1 % with a color coordinate of (0.15, 0.16) at 1,000 cd/$m^2$ was obtained in the deep blue device and a high quantum efficiency of 15.2 % with a color coordinate (0.30, 0.32) was obtained in the pure white organic light-emitting diodes. The quantum efficiency of the pure white device is the best quantum efficiency value reported in the pure white device up to now.

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Quality Characteristics of Cookies Added with Ginseng Leaf (인삼 잎을 첨가한 쿠키의 품질 특성)

  • Kim, Dam;Kim, Kyoung-Hee;Yook, Hong-Sun
    • Korean journal of food and cookery science
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    • v.30 no.6
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    • pp.679-686
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    • 2014
  • This study was carried out to evaluate the quality characteristics of cookies added with various concentrations (0, 1, 3 and 5%) of ginseng leaf powder. The pH of the cookies significantly decreased with increased ginseng leaf powder concentrations (p<0.05), but the density of cookies showed no significant differences. Spread factor, loss rate, and leaving rate of cookies decreased according to the amount of added ginseng leaf powder. The lightness and yellowness of cookies decreased as the concentration of the ginseng leaf powder increased whereas no significant difference in the redness was found with increased ginseng leaf concentration. In the texture analysis, the hardness of the cookies increased according to the concentration of ginseng leaf. DPPH free radical scavenging activity of the cookies significantly increased with increased ginseng leaf concentration (p<0.05). In the sensory evaluation, sensory scores for color, taste and overall acceptability were highest in the 3% ginseng leaf cookies. Thus, our results suggested that the optimum amount of ginseng leaf powder to add to cookies was 3%.

The study on the BTEX Concentration of Soil in Gas Station (국내 주유소 토양의 BTEX 오염에 관한 연구)

  • Shin, Joung-Nam;Roh, Sung-Hyeuk;Jung, Sang-Rak;Oh, Gil-Rok;Kim, Mi-Kyoung;Yook, Woon-Soo
    • Journal of Soil and Groundwater Environment
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    • v.19 no.6
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    • pp.18-23
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    • 2014
  • The BTEX contamination of soil around gas station in Korea was investigated in 53 gas stations in 2013 by official test method on soil pollution. Each gas station was divided into oil tank area, line area, and surrounding area. The concentration of BTEX in 1066 sites of 53 gas stations was N.D.~ 3437.36 mg/kg. The order of average concentration for area was as follows: line area ($20.91{\pm}144.79mg/kg$) > tank area ($15.11{\pm}110.08mg/kg$) > surrounding area ($10.79{\pm}111.40mg/kg$). It was the number of sampling site exceeding regulatory levels at surrounding area the most at all. The average concentration of xylene was the highest, while that of ethylbenzene was the lowest.