Reflective Colored Organic Light-Emitting Diodes for Light-Adaptable Display

Lim, Jong Tae,Ahn, Joon Tae,Lee, Jonghee,Moon, Jaehyun,Cho, Seong M.,Ah, Chil Seong,Lim, Seong Chu,Lee, Jeong-Ik American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.11

<P>A new light-adaptable display (LAD), consisting of reflective, colored, organic light-emitting diodes (RCOLEDs) and an optical shutter (OS), was fabricated. The RCOLED is composed of a color-selective reflective filter (CSRF) functioning in reflective mode under bright conditions, and a transparent OLED (TOLED) working in emissive mode under relatively dark conditions. The OS functions to pass or shield the light generated in the TOLED or from the outer environment. In this RCOLED, the CSRF was designed based on the concept of Fabry-Perot interferometry to represent a specific color of red, blue, and green. The TOLED was designed using a low-reflective multi-layered graphene as an top electrode to suppress the distorted optical interference from reflective mirrors in the RCOLED. The color reproduction range calculated from RCOLEDs with a graphene top electrode was dramatically improved (35.0%), compared to that computed from RCOLEDs with a semi-transparent thin-silver top electrode (2.4%). Finally, we demonstrate that the new dual-mode LAD works well.</P>

A strategy for forming robust adhesion with the substrate in a carbon-nanotube field-emission array

Lim, Seong Chu,Choi, Ha Kyu,Jeong, Hee Jin,Song, Young Il,Kim, Gil Yong,Jung, Kyung Taek,Lee, Young Hee Elsevier 2006 Carbon Vol.44 No.13

<P><B>Abstract</B></P><P>A method of how to form a strong adhesion of carbon nanotubes (CNTs) to substrate by introducing an intermediate metal layer in fabricating spray-based field emitters and its effect to the field-emission properties were addressed. An Indium or tin layer was deposited on an indium-tin-oxide glass substrate and thermally annealed to hold the CNTs tightly. This underlying metal layer forms a strong bond to CNTs by wetting while melting without any detectable evaporation of metal atoms. This gave rise to a stable field-emission current at high voltage, which was confirmed by a mass spectrometer. The tube density and field-emission characteristics strongly depend on the annealing temperature of metal layers.</P>

Fluidic Properties of Carbon Nanotube Inks and Field Emission Properties of Ink Jet-Printed Emitters

Lim, Seong Chu,Lee, Dae Sik,Kim, Ki Kang,Choi, Young Chul,Kim, Hun Soo,Lee, Jin Hyon,Paik, Ungyu,Lee, Young Hee IOP Publishing 2009 Japanese journal of applied physics Vol.48 No.11

Effect of Gas Exposures on Field Emission Properties of Carbon Nanotube Arrays

Lim, Seong-Chu,Choi, Young-Chul,Jung, Hee-Jin,Shin, Young-Min,Bae, Dong Jae,Lee, N. S.,Kim, J. M.,Lee, Young Hee 선문대학교 첨단과학기술연구소 2001 첨단과학기술연구소 논문집 Vol.5 No.-

We have investigated the field emission properties from the CNT-FEA by exposing various gases, We find that gas adsorbates played a crucial role in the formation of saturation currents at high field. The existence of the hysteresis loop during the rise and fall sweeps originates from the presence of the gas adsorbates. Oxygen and nitrogen gases show different trends in the change of the emission properties from hydrogen gases. The changes of the slopes. turn-on voltages, and saturation currents at high field are strongly correlated to the electronegativity of the individual Species and nature of the adsorption. We conclude that oxygen gases dominate the filed emission properties upon adsorption and even degrade the surface morphologies with possible oxidative etching process, whereas hydrogen gases give the least effects to the field emission properties, by simply cleaning up the surface of the CNT-FEA.

Extracting independently the work function and field enhancement factor from thermal-field emission of multi-walled carbon nanotube tips

Lim, Seong Chu,Jeong, Hee Jin,Kim, Keun Soo,Lee, Im Bok,Bae, Dong Jae,Lee, Young Hee Elsevier 2005 Carbon Vol.43 No.13

<P><B>Abstract</B></P><P>We have characterized the emission properties of multi-walled carbon nanotubes (MWCNTs) grown by thermal chemical vapor deposition (CVD). Our characterizations have been conducted in the thermal-field (T-F) zone, a narrow transition zone between field emission and thermionic emission. The characteristic <I>I</I>–<I>V</I> curve in T-F zone, designated to Christov plot, is advantageous to extract independently the field enhancement factor and work function at the emitting site. Our approach is more reliable than Fowler–Nordheim (F–N) plot whose linear region provides the solution with two unknowns. On the other hand, the Christov plot in the T-F zone provides the solution with only the field enhancement factor. Using the general theory of electron emission, we find that the work function and field enhancement factor of the CVD-grown MWCNTs are 4.7±0.4eV and 3300±200, respectively.</P>

The Response to Transarterial Chemoembolization According to the Post-Operative Recurrence Patterns in Combined Hepatocellular-Cholangiocarcinoma

( Seong Kyun Na ),( Han Chu Lee ),( Gwang Hyeon Choi ),( Jihyun An ),( Dan Bi Lee ),( Ju Hyun Shim ),( Kang Mo Kim ),( Young-suk Lim ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: Combined HCC-CC (cHCC-CC) is presented as hypervascular tumor or peripheral enhancing tumor in dynamic CT scan. We evaluated the effect of transarterial chemoembolization (TACE) and prognosis according to the post-operative recurrence imaging patterns of cHCC-CC. Methods: We retrospectively analyzed 43 cHCC-CC patients who were treated with TACE for 1^st post-operative recurrence after curative surgical resection between January 2000 and May 2016 and 59 hepatocellular carcinoma (HCC) patients between January 2008 and June 2008 at Asan Medical Center in Korea. Tumor with arterial enhancement more than 50% of tumor volume in CT was classified as hypervascular tumor, in contrast, tumor with peripheral enhancement were classified as peripheral enhancing tumor. Tumor responses were evaluated according to RECIST 1.1 criteria. Results: The median follow up duration was 53.5 months (interquartile range: 23.2 - 101.8 months). In cHCC-CC group, primary hypervascular and peripheral enhancing tumor were in 19 patients and 24 patients. Hypervascular recurred tumor and peripheral enhancement recurred tumor were in 26 patients and 17 patients. Agreement of imaging patterns between primary tumor and recurred tumor was 78.9% in hypervascular tumor, and 54.2% in peripheral enhancement tumor. After TACE, disease control rate was 84.7% in HCC, 88.5% in hypervascular recurred tumor, and 58.8% in peripheral enhancing recurred tumor (P-value = 0.034). The median survival time after recurrence for HCC was 67.5 months (95% CI 34.5 - 100.6 months) and 52.8 months (95% CI 6.4 - 99.2 months) for hypervascular recurred tumor and 12.4 months (95% CI 8.5 - 16.3 months) for peripheral enhancement recurred tumor (P-value < 0.001). In multivariable Cox regression, peripheral enhancing recurred tumor (HR 3.827, 95% CI 1.544 - 9.489, P-value = 0.004), progressive disease after TACE (HR 3.099, 95% CI 1.208 - 7.950, P-value = 0.019), and recurred tumor size > 2 cm (HR 2.882, 95% CI 1.250 - 2.644, P-value = 0.013) were significant prognostic factors. Conclusions: Recurred cHCC-CC with peripheral enhancement showed poor tumor response for TACE and poor prognosis after recurrence than hypervascular recurred tumor.

소아중증 독사 교상 환자의 치험 1례

임치영,이정한,문태일,추용식,고대이,손석우,최성욱,김옥준 대한응급의학회 2004 大韓應急醫學會誌 Vol.15 No.2

Effects of the Loading Rate and Humidity in the Fracture Toughness Testing of Alumina

Cho, Seong-Jai,Kim, Jai-Chun,Yoon, Kyung-Jin,Chu, Min-Cheol,Lee, Yoon-Cheol,Quinn George,Lee, Hong-Lim The Korean Ceramic Society 2006 한국세라믹학회지 Vol.43 No.1

To test the fracture toughness of alumina; a Surface-Crack-in-Flexure (SCF) method, a Single-Edge-Precracked-Beam (SEPB) method and a Single-Edge-V-Notched-Beam (SEVNB) method were used at crosshead rates ranging from 0.005 mm/min to 2 mm/ min and relative humidity ranging from $15\%\;to\;80\%$. The results show that the fracture toughness tested by the SCF method increases with either an increasing loading rate or decreasing relative humidity; in contrast, the toughness by the SEPB method and the SEVNB method does not depend on the loading rate or the relative humidity. Theoretical analysis of the way slow crack growth affects the apparent fracture toughness indicates that the three testing methods have different effects with respect to the loading rate and the relative humidity; moreover, these differences are attributable to differences in the size of the cracks or notches.

Near-ultraviolet light-emitting diodes with transparent conducting layer of gold-doped multi-layer graphene

Cho, Chu-Young,Choe, Minhyeok,Lee, Sang-Jun,Hong, Sang-Hyun,Lee, Takhee,Lim, Wantae,Kim, Sung-Tae,Park, Seong-Ju American Institute of Physics 2013 JOURNAL OF APPLIED PHYSICS - Vol.113 No.11

태블릿PC 어플리케이션을 이용한 인지훈련이 뇌졸중 환자의 인지 기능과 우울 및 불안에 미치는 영향

임이원 ( Lim Lee-won ),김윤성 ( Kim Yoon-seong ),김예지 ( Kim Ye-ji ),윤혜영 ( Yun Hye-young ),추선경 ( Chu Sun-kyoung ),최혜림 ( Choi Hye-rim ) 대한인지재활학회 2019 대한인지재활학회지 Vol.8 No.2

본 연구는 태블릿PC 어플리케이션을 이용한 인지훈련이 뇌졸중 환자의 인지와 우울 및 불안에 미치는 효과에 대해 알아보고자 하였다. 재활치료를 받는 뇌졸중 환자 5명을 대상으로 태블릿PC 어플리케이션은 6주간, 주 3회, 1일 30분 동안 실시하였으며, 연구자 1인의 진행 하에 초기 평가 이후 6주 후에 재평가가 이루어졌으며, 본 연구의 모든 평가는 연구자 1인이 단독으로 실시하여 일관성을 유지하도록 하였다. 태블릿 PC를 이용한 인지훈련 실시 전과 후의 한국형간이 정신 상태 검사(MMSE-K)의 점수를 비교한 결과 실시 전 22.40±0.55점에서 실시 후 24.40±0.55점으로 통계적으로 유의미한 증가를 보였다(p= 0.04, p<.05). 한국판 노인형 기호잇기검사(Korean Trail Making Test for the Elderly A; K-TMT-e A)의 점수를 비교한 결과 실시 전 64.63±11.62초에서 실시 후 52.80±11.91초로 통계적으로 유의미한 감소를 보였다(p= 0.04, p<.05). 한국판 노인형 기호잇기검사(Korean Trail Making Test for the Elderly B; K-TMT-e B)의 점수를 비교한 결과 실시 전 136.06±17.65초에서 실시 후 120.65±17.13초로 통계적으로 유의미한 감소를 보였다(p= 0.04, p< .05). 숫자 외우기 검사(Digit Span; DS)의 점수를 비교한 결과 실시 전 3.40±0.55점에서 실시 후 3.80±0.45점으로 점수의 변화는 있었으나 통계적으로 유의미하지 않았다(p= 0.16, p >.05). 벡의 우울 척도 검사(Beck Depression Inventory; BDI) 점수를 비교한 결과 실시 전 21.80±12.19점에서 실시후 20.00±11.33점으로 통계적으로 유의한 감소를 보였다(p= 0.04, p<.05). 벡 불안 척도(Beck Anxiety Inventory; BAI)의 점수를 비교한 결과 실시 전 34.40±13.96점에서 실시 후 29.20±12.97점으로 통계적으로 유의한 감소를 보였다 (p= 0.04, p<.05). 따라서 스마트 기기를 활용한 어플리케이션 기반의 인지훈련이 인지 기능을 향상시킨다는 선행연구에 추가적인 증거를 제공하였을 뿐만 아니라 나아가 뇌졸중 환자의 우울 및 불안과 같은 정서적인 문제에 태블릿 PC가 효과적으로 사용될 수 있을 것으로 사료된다. This study aimed to investigate the effects of cognitive training using a tablet PC application on cognition, depression and anxiety in patients with stroke. In this study, five patients with stroke undergoing rehabilitation received cognitive training using a tablet PC application for 30 minutes per session, three times per week during 6 weeks. An initial evaluation was conducted by one researcher, and then a reevaluation was made six weeks later. All evaluations in this study were conducted by one single researcher to ensure consistency in the evaluation. The results of comparing the MMSE-K scores before and after the cognitive training using a tablet PC application showed that there was a statistically significant increase in the MMSE-K score from 22.40 ± 0.55 points before the intervention to 24.40 ± 0.55 points after the intervention (p=0.04, p <.05). The results of comparing the scores of the Korean version of the Trail Marking Test-A for elderly persons before and after the intervention showed that there was a statistically significant decrease in from 64.63±11.62 seconds before the intervention to 52.80±11.91 seconds after the intervention (p=0.04, p<.05). The results of comparing the scores of the Korean version of the Trail Marking Test-B for elderly persons before and after the intervention showed that there was a statistically significant decrease in from 136.06±17.65 seconds before the intervention to 120.65±17.13 seconds after the intervention (p=0.04, p< .05). The results of comparing the Digit Span (DS) scores before and after the intervention showed that there was a change in score from 3.40 ± 0.55 point before the intervention to 3.80 ± 0.45 point after the intervention, but it was not statistically significant (p=0.16, p >.05). The results of comparing the Beck Depression Inventory (BDI) scores before and after the intervention showed that there was a statistically significant decrease in BDI score from 21.80 ± 12.19 points before the intervention to 20.00 ± 11.33 points after the intervention (p= 0.04, p<.05). The results of comparing of comparing Beck Anxiety Inventory (BAI) before and after the intervention showed that there was a statistically significant decrease in BAI score from 34.40±13.96 to 29.20±12.97 (p= 0.04, p<.05). Therefore, the results of this study provided additional evidence to previous studies revealing that smart device application-based cognitive training improved cognitive function. Furthermore, it is thought that tablet PCs can be effectively used for emotional problems such as depression and anxiety in stroke patients.