Highly efficient and low voltage silver nanowire-based OLEDs employing a n-type hole injection layer.

Lee, Hyungjin,Lee, Donghwa,Ahn, Yumi,Lee, Eun-Woo,Park, Lee Soon,Lee, Youngu RSC Pub 2014 Nanoscale Vol.6 No.15

<P>Highly flexible and efficient silver nanowire-based organic light-emitting diodes (OLEDs) have been successfully fabricated by employing a n-type hole injection layer (HIL). The silver nanowire-based OLEDs without light outcoupling structures exhibited excellent device characteristics such as extremely low turn-on voltage (3.6 V) and high current and power efficiencies (44.5 cd A(-1) and 35.8 lm W(-1)). In addition, flexible OLEDs with the silver nanowire transparent conducting electrode (TCE) and n-type HIL fabricated on plastic substrates showed remarkable mechanical flexibility as well as device performance.</P>

Highly stable and flexible silver nanowire-graphene hybrid transparent conducting electrodes for emerging optoelectronic devices.

Lee, Donghwa,Lee, Hyungjin,Ahn, Yumi,Jeong, Youngjun,Lee, Dae-Young,Lee, Youngu RSC Pub 2013 Nanoscale Vol.5 No.17

<P>A new AgNW-graphene hybrid transparent conducting electrode (TCE) was prepared by dry-transferring a chemical vapor deposition (CVD)-grown monolayer graphene onto a pristine AgNW TCE. The AgNW-graphene hybrid TCE exhibited excellent optical and electrical properties as well as mechanical flexibility. The AgNW-graphene hybrid TCE showed highly enhanced thermal oxidation and chemical stabilities because of the superior gas-barrier property of the graphene protection layer. Furthermore, the organic solar cells with the AgNW-graphene hybrid TCE showed excellent photovoltaic performance as well as superior long-term stability under ambient conditions.</P>

교통네트워크를 이용한 국가행정기능 이전에 따른 행정중심지 접근성 평가

이형진 ( Hyungjin Lee ),서교 ( Kyo Suh ),이지민 ( Jimin Lee ),김태곤 ( Taegon Kim ),이정재 ( Jeong Jae Lee ) 한국농공학회 2013 한국농공학회 학술대회초록집 Vol.2013 No.-

정부 주요 부처의 세종시 이전이 본격화되면서 과천정부청사와 비교해 세종정부청사의 지리적 이점이 주목받고 있다. 그러나 인구 및 주요 공공기관이 밀집되어있는 서울, 경기권에서 멀어짐에 따라 불만여론이 발생하는 등 접근성 변화에 대해서 살펴볼 필요가 있다. 따라서 본 연구에서는 전국 15개 시ㆍ도 지방행정중심지에서 과거와 현재의 행정중심지로의(과천정부청사, 세종정부청사로의) 지리적 접근성을 비교, 분석하고자 하였다. 본 연구에서는 기존의 일차원적인 접근성 분석과 달리 도로 및 철도 등의 교통망 네트워크와 15개 시도의 사회ㆍ경제적 변수를 적용하여 다각적으로 두 정부청사의 접근성을 분석하였다. 분석 결과, 세종정부청사는 과천정부청사와 비교해 지리적인 이점을 가지는 것이 분명하지만 다양한 변수를 적용하였을 때 접근성은 오히려 낮은 것으로 나타났다. 15개 시도의 인구, GDP 등을 가중치로 적용하여 교통망 네트워크를 기반으로 분석할 경우 행정 수도 이전에 따른 접근성의 이점은 크지 않은 것으로 나타났다. 특히 가장 큰 경제 규모를 가진 서울, 경기도에서 세종정부청사로의 접근성이 과천정부청사와 비교해서 크게 낮아지는 것으로 나타났다. 따라서 향후 현재 수도권을 중심으로 형성된 경제, 사회, 문화적인 요소들과 다양한 국가 기관의 지방 분산이 진행되면 세종정부청사의 접근성은 보다 개선될 수 있을 것으로 판단된다.

A Long-Term Comparative Study on Macrolepidoptera Diversity in Three Types of Vegetations from Worak-san [Mt.] in 2009

Eunsol Lee,Hyungjin Park,Seongkyun Lee,Seulki Kim,Jung Min Han,Taeho Kim,Chang gi Hong,Soowon Cho 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.05

With the help of KLTER/ME and KLPS in Woraksan, we have surveyed monthly diversity and seasonal prevalence of Macrolepidoptera in Wol-ak-san [Mt.] for the period of five months from May to September since 2005. Since 2007, to reduce variation, we chose two monitoring points, instead of one, for each of the three representative vegetations: Quercus mongolica-, Quercus variabilis- and Pinus densiflora-formations, abbreviated as QM, QV and PD, respectively, and collected exclusively larger moths with bucket-type of light traps for quantified survey. In 2009, as a result, QV showed higher species diversity and specimen number than QM or PD although the differences between QV and QM are subtle. The number of individuals collected may not be a good indicator, e.g., Idaea biselata collected in QM in June was over 200 in 2007, which is more than twice the number of specimens in all other sites per month, while the number in 2008 was dropped to only 10 specimens. In 2009, they became a dominant species again, showing biennial dominancy trend. It also seems that we are experiencing major decline of specimen numbers: 651 specimens collected in 2009 while 874 specimens collected in 2008, which was already a big reduction compared to over 2500 specimens in 2007

라즈베리파이를 이용한 학내 유동인구 측정

이형진(Hyungjin Lee),이정현(Jeonghyeon Lee),김민성(Minsung Kim),남현규(Hyungyu Nam),문현수(Hyunsu Mun),이영석(Youngseok Lee) 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.12

가이드라인의 변화에 따른 농업부문 온실가스 배출량 분석

이형진 ( Hyungjin Lee ),서교 ( Kyo Suh ),김태곤 ( Taegon Kim ),배연정 ( Yeon Joung Bae ),김건엽 ( Gun Yeup Kim ),이지민 ( Jimin Lee ),이정재 ( Jeongjae Lee ) 한국농공학회 2013 한국농공학회 학술대회초록집 Vol.2013 No.-

최근 기후변화 및 지구온난화에 대한 전세계적으로 관심이 증대되면서 지구온난화의 주요원인인 온실가스 배출규제를 위해 다양한 노력이 진행되고 있다. 각 국가는 국가별 다양한 부문의 온실가스 관련 정보들을 작성하여 온실가스 배출량 조절을 위해 온실가스 배출량의 정량적 목표제시 등에 활용하고 있다. 현재 UNCCC에 포함된 41개국이 국가온실가스 보고서(NIR)를 제출하고 있으며 우리나라도 곧 의무적으로 보고해야할 것으로 보인다. 하지만 각 부문별로 활동자료 및 배출계수의 자료 수급이 어려워 산정되지 못하거나 국가 통계에 의존하여 작성되는 부분이 많은 등 정확한 국가 온실가스 보고서 작성에 난항이 예상되는 상황이다. 특히 2006년 변화된 IPCC 가이드라인에 의하면 농업부문이 배출원이면서 동시에 흡수원으로 정의되므로 농업부문에서 배출되는 온실가스에 대한 이해와 배출량을 정확히 산정할 수 있는 연구가 필요하다. 또한 기후변화에 가장 많은 영향을 받는 산업이며 배출원에 대한 활동자료 구축이 타부문에 비해서 미비한 상황이다. 본 연구에서는 농업부문의 정확한 온실가스 배출량 산정을 위해 IPCC에서 제시하는 온실가스배출정보 가이드라인에 적합한 활동자료와 배출계수에 대해 분석하고, 변화된 가이드라인에 따른 배출량 산정 및 개선방안을 제시하고자 한다.

관개수로에서의 표면유속 보정기술 개발

신형진(Shin, Hyungjin),이기원(Lee, Ki Won),이재남(Lee, Jaenam),이현석(Lee, Hyun Seok),최은혁(Choi Eunhyuk),이규상(Lee, Gyusang) 대한토목학회 2021 대한토목학회 학술대회 Vol.2021 No.10

A Long-Term Comparative Study on Macrolepidoptera Diversity in Three Types of Vegetations from Worak-san [Mt.] in 2010

So-Young Lee,Eunsol Lee,Seongkyun Lee,Seulki Kim,Taeho Kim,Chang gi Hong,Hyungjin Park,Soowon Cho 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.05

We have surveyed monthly diversity and seasonal prevalence of Macrolepidoptera in Wol-ak-san [Mt.] for the period of four months from May to August in 2010. Although it is not a part of KLTER/ME and KLPS study in Wol-ak-san conducted in recent few years, this year's data may be comparable with the previous ones as the collection sites and dates are very similar. The three representative vegetations are Quercus mongolica-, Quercus variabilis- and Pinus densiflora-formations, abbreviated as QM, QV and PD, respectively, and we collected exclusively larger moths with bucket-type of light traps for quantified survey. In 2010, as a result, QV showed higher species diversity and specimen number than QM or PD although the differences between QV and QM are very subtle. The result is very similar to the result in 2009. The only difference in 2010 over 2009 is that the number of species, not specimens, has been increased 1.5 times, and this may be caused by the inclusion of July records, which has been usually deleted due to heavy rainy season causing poor collection records. The number of species in Noctuidae was the highest in 2010, about twice more than that in 2009, but the dominant species in 2010 were either Pyralidae (Nacoleia commixta or Bradina geminalis) or Geometridae (Arichanna melanaria). We are still experiencing decline of specimen numbers: 567 specimens collected in 2010 while 651 in 2009 and 874 in 2008, which was already a huge reduction compared to over 2500 specimens in 2007.

Asset Growth and Analysts' Multi-Period Earnings Forecasts

( Hyungjin Cho ),( Sunhwa Choi ),( Lee-seok Hwang ),( Woo-jong Lee ) 한국회계학회 2018 會計學硏究 Vol.43 No.2

Using analysts' multi-period earnings forecasts, we examine whether analyst forecast bias is related to asset growth. We find that analyst forecasts are more optimistic for firms with higher asset growth. This relation is particularly noticeable for longer-term (e.g., two- and three-year-ahead) forecasts than for shorter-term (e.g., one-year-ahead) forecasts. Moreover, analyst optimism for high-growth firms is greater for 1) firms that have maintained similar levels of growth over recent periods, 2) firms with higher information uncertainty, and 3) forecasts with longer forecast horizons (e.g., forecasts issued far before the fiscal year-end). We examine to what extent analyst optimism for high-growth firms explains the asset growth effect (i.e., a negative association between asset growth and subsequent stock returns). Controlling for forecast bias in a growth-return regression substantially attenuates the asset growth effect, suggesting that forecast bias plays an important role in the asset growth effect. Path analysis further suggests that analysts' long-term (but not short-term) forecast bias is an important mediator through which biased expectations about asset growth are incorporated into stock prices. Overall, our findings are consistent with the extrapolation bias explanation for the asset growth effect.

CT Examinations for COVID-19: A Systematic Review of Protocols, Radiation Dose, and Numbers Needed to Diagnose and Predict

Lee Jong Hyuk,Hong Hyunsook,Kim Hyungjin,Lee Chang Hyun,Goo Jin Mo,Yoon Soon Ho 대한영상의학회 2021 대한영상의학회지 Vol.82 No.6

Purpose Although chest CT has been discussed as a first-line test for coronavirus disease 2019 (COVID-19), little research has explored the implications of CT exposure in the population. To review chest CT protocols and radiation doses in COVID-19 publications and explore the number needed to diagnose (NND) and the number needed to predict (NNP) if CT is used as a first-line test. Materials and Methods We searched nine highly cited radiology journals to identify studies discussing the CT-based diagnosis of COVID-19 pneumonia. Study-level information on the CT protocol and radiation dose was collected, and the doses were compared with each national diagnostic reference level (DRL). The NND and NNP, which depends on the test positive rate (TPR), were calculated, given a CT sensitivity of 94% (95% confidence interval [CI]: 91%–96%) and specificity of 37% (95% CI: 26%–50%), and applied to the early outbreak in Wuhan, New York, and Italy. Results From 86 studies, the CT protocol and radiation dose were reported in 81 (94.2%) and 17 studies (19.8%), respectively. Low-dose chest CT was used more than twice as often as standarddose chest CT (39.5% vs.18.6%), while the remaining studies (44.2%) did not provide relevant information. The radiation doses were lower than the national DRLs in 15 of the 17 studies (88.2%) that reported doses. The NND was 3.2 scans (95% CI: 2.2–6.0). The NNPs at TPRs of 50%, 25%, 10%, and 5% were 2.2, 3.6, 8.0, 15.5 scans, respectively. In Wuhan, 35418 (TPR, 58%; 95% CI: 27710–56755) to 44840 (TPR, 38%; 95% CI: 35161–68164) individuals were estimated to have undergone CT examinations to diagnose 17365 patients. During the early surge in New York and Italy, daily NNDs changed up to 5.4 and 10.9 times, respectively, within 10 weeks. Conclusion Low-dose CT protocols were described in less than half of COVID-19 publications, and radiation doses were frequently lacking. The number of populations involved in a first-line diagnostic CT test could vary dynamically according to daily TPR; therefore, caution is required in future planning.