Direct Integration of Polycrystalline Graphene into Light Emitting Diodes by Plasma-Assisted Metal-Catalyst-Free Synthesis

Kim, Yong Seung,Joo, Kisu,Jerng, Sahng-Kyoon,Lee, Jae Hong,Moon, Daeyoung,Kim, Jonghak,Yoon, Euijoon,Chun, Seung-Hyun American Chemical Society 2014 ACS NANO Vol.8 No.3

<P>The integration of graphene into devices is a challenging task because the preparation of a graphene-based device usually includes graphene growth on a metal surface at elevated temperatures (∼1000 °C) and a complicated postgrowth transfer process of graphene from the metal catalyst. Here we report a direct integration approach for incorporating polycrystalline graphene into light emitting diodes (LEDs) at low temperature by plasma-assisted metal-catalyst-free synthesis. Thermal degradation of the active layer in LEDs is negligible at our growth temperature, and LEDs could be fabricated without a transfer process. Moreover, <I>in situ</I> ohmic contact formation is observed between DG and p-GaN resulting from carbon diffusion into the p-GaN surface during the growth process. As a result, the contact resistance is reduced and the electrical properties of directly integrated LEDs outperform those of LEDs with transferred graphene electrodes. This relatively simple method of graphene integration will be easily adoptable in the industrialization of graphene-based devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2014/ancac3.2014.8.issue-3/nn405477f/production/images/medium/nn-2013-05477f_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn405477f'>ACS Electronic Supporting Info</A></P>

Hollow fiber membrane process for SO₂ removal from flue gas

Kim, KeeHong,Kim, JongHak,Lee, HyungKeun John WileySons, Ltd 2015 Journal of chemical technology and biotechnology Vol.90 No.3

<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>In this study, a polymeric membrane process was investigated to avoid the poisoning of CO<SUB>2</SUB> sorbents with SO<SUB>2</SUB> during the carbon capture and separation (CCS) process. Two types of hollow fiber composite membranes were prepared using poly(ether‐<I>b</I>‐amide) (PEBAX) and cellulose acetate (CA) as composite materials.</P><P><B>RESULTS</B></P><P>Both of the composite membranes exhibit a trade‐off between the pure gas permeance and the ideal selectivity. The PEBAX1657/PEI exhibited higher permeance than CA/PES due to the morphology of the substrate and the effects of the coating material. A mixed‐gas separation experiment investigated the SO<SUB>2</SUB> removal efficiency and the CO<SUB>2</SUB> loss ratio. The SO<SUB>2</SUB> removal efficiency and CO<SUB>2</SUB> loss ratio were found to be positively correlated with the permeance of the gas components. A multi‐stage membrane process was designed to reduce the CO<SUB>2</SUB> loss ratio with a 90% removal efficiency of SO<SUB>2</SUB>. Compared with a single‐stage process, the CO<SUB>2</SUB> loss ratio was decreased by up to 16.1%, and the membrane area was estimated at 18.1 m<SUP>2</SUP> for the multi‐stage process.</P><P><B>CONCLUSION</B></P><P>A multi‐stage membrane process was designed using different types of membrane modules to decrease CO<SUB>2</SUB> loss ratio without sacrificing SO<SUB>2</SUB> removal efficiency. © 2014 Society of Chemical Industry</P>

Water vapor removal using CA/PEG blending materials coated hollow fiber membrane

Kim, KeeHong,Ingole, Pravin G.,Yun, SangHee,Choi, WonKil,Kim, JongHak,Lee, HyungKeun John WileySons, Ltd 2015 Journal of chemical technology and biotechnology Vol.90 No.6

<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P>In this study, a polyethersulfone composite hollow fiber membrane was used for the separation of water vapor from mixed gas. For improvement of the separation properties, the fabricated membrane was coated with cellulose acetate (CA) and polyethylene glycol (PEG).</P><P><B>RESULTS</B></P><P>Experiments on the permeation of water vapor and N<SUB>2</SUB> gas mixture were performed to observe membrane behavior as a function of the coating conditions, such as the composition and molecular weight of PEG. The water vapor permeance and selectivity of water vapor/N<SUB>2</SUB> improved from 68.5 GPU to 444.1 GPU and from 76.1 to 175.5, respectively, using 5 wt% PEG 2000 blended coating solution.</P><P><B>CONCLUSION</B></P><P>An increase in the PEG content and molecular weight of the coating solution affected the permeance and selectivity due to the hydrophilicity of PEG and the structural changes of the coating layer. © 2014 Society of Chemical Industry</P>

Ex-post Evaluation of Korea Expressway(7ⅹ9): Focus on Direct and Indirect Effect

Jonghak, Kim,Yongseok, Ko 한국도로학회 2018 한국도로학회 학술대회 발표논문 초록집 Vol.2018 No.05

This case study explained the korea expressway’s ex-post evaluation that focused on the direct and indirect effects of expressway, constructed for 40years. Expressway has been the foundation of South Korean economy and society since 1970. But there was a few research of the various effect of expressway. This case study tried to qualitatively analyze the direct and indirect effects of expressway. This case study suggested the expressway’s various effects separated by a 10year from 1970 to 2010 and calculated the monetary value of expressway network by transport network analysis. Also, it suggested the SA(Service area) of express network from 1970 to 2010 by ArcGis’s IDW methodology. Especially, the regional and industry development effect of expressway was calculated in this study by adapting the function of Cobb-Douglas production.

FaceCAPTCHA: a CAPTCHA that identifies the gender of face images unrecognized by existing gender classifiers

Kim, Jonghak,Kim, Sangtae,Yang, Joonhyuk,Ryu, Jung-hee,Wohn, KwangYun Springer-Verlag 2014 MULTIMEDIA TOOLS AND APPLICATIONS Vol.72 No.2

AgeCAPTCHA: an Image-based CAPTCHA that Annotates Images of Human Faces with their Age Groups

( Jonghak Kim ),( Joonhyuk Yang ),( Kwangyun Wohn ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.3

Annotating images with tags that describe the content of the images facilitates image retrieval. However, this task is challenging for both humans and computers. In response, a new approach has been proposed that converts the manual image annotation task into CAPTCHA challenges. However, this approach has not been widely used because of its weak security and the fact that it can be applied only to annotate for a specific type of attribute clearly separated into mutually exclusive categories (e.g., gender). In this paper, we propose a novel image annotation CAPTCHA scheme, which can successfully differentiate between humans and computers, annotate image content difficult to separate into mutually exclusive categories, and generate verified test images difficult for computers to identify but easy for humans. To test its feasibility, we applied our scheme to annotate images of human faces with their age groups and conducted user studies. The results showed that our proposed system, called AgeCAPTCHA, annotated images of human faces with high reliability, yet the process was completed by the subjects quickly and accurately enough for practical use. As a result, we have not only verified the effectiveness of our scheme but also increased the applicability of image annotation CAPTCHAs.

일본의 근대 실증사학의 에토스(ethos)와 다보하시 기요시(田保橋潔)의 조선사 연구

김종학 ( Kim Jonghak ) 이화여자대학교 한국문화연구원 2018 한국문화연구 Vol.34 No.-

이 글의 목적은 일본의 근대 실증사학이 형성된 역사적 배경을 살펴보고, 그 맥락에서 다보하시 기요시(田保橋潔)의 조선사 연구의 특징과 한계를 고찰하는 데 있다. 모든 역사학은 기본적으로 실증을 추구한다는 점에서 실증사학이라는 말은 동어반복에 지나지 않는다. 이 글은 일본의 근대 실증사학의 본질은 사료의 수집과 해석에 관한 합리적 방법론이 아니라, 역사가의 존재와 목소리를 감추는 것을 미덕으로 여기는 역사학계의 에토스에 있었다고 주장한다. 랑케사학의 권위는 역사가들이 그 역할을 방대한 1차 문헌의 수집과 정리로 제한하는 것을 정당화했지만, 그 전유(專有) 과정에서 본연의 역사신학적 전제나 독일 역사주의 전통이 사상(捨象)된 것 또한 불가피한 귀결이었다. 다보하시 기요시의 조선사 연구, 특히 『근대 일선관계의 연구(近代日鮮關係の硏究)』(1940)는 근대 일본 실증사학의 전범(典範)이었다. 그러나 역사가가 주관을 배제하고 1차 문헌에 기록된 대로만 역사를 서술하면 객관적 진리에 도달할 수 있다는 근대 실증사학의 전망은 끝내 실현되지 않았다. 다보하시의 조선사 연구에서 나타난 불편한 진실에 대한 침묵이나 역사인식의 범용함과 같은 문제점은 상당부분 근대 일본 실증사학의 에토스로부터 유래한 병증(病症)이었다. This article examines the historical background in which the modern Japanese positive history was formed, and in that context, considers the features and fundamental problems of Tabohashi Kiyoshi’s study on Joseon history. The word “positive history” is no more than a tautology that historians basically try to base their works on concrete grounds. I argue, therefore, that we should find the essence of modern Japanese positive history from the ethos of the academia that regards hiding the voice and existence of a historian as a virtue, rather than a rational methodology concerning the collection or interpretation of historical documents. Obviously the unchallengeable authority of Ranke justified the practice of limiting the role of a historian to mere collection and compilation of massive primary literatures, but in the course of an appropriation, the hidden premises of historical theology or the tradition of the German Historicism inherent in Ranke’s historical study were inevitably missed. Tabohashi Kiyoshi’s studies on Joseon history, especially his book Kindai Nichi-sen Kankei no Genkyu(A Study on the Modern Japan-Joseon Relations) has been regarded as a canon of the modern Japanese positive history. Nevertheless, the prospect that a historian could reach the objective truth if only he rewrites the history as recorded in historical documents has never been realized. The intentional silence about inconvenient truths and the mediocrity of historical perception of Tabohashi’s works were consequences stemmed from the ethos of the modern Japanese positive history.

자서전적 기억을 활용한 디지털 사진의 색인 및 검색에 대한 연구

김종학(Jonghak Kim),류중희(Jung-hee Ryu) 한국멀티미디어학회 2010 한국멀티미디어학회 학술발표논문집 Vol.2010 No.1

본 논문에서는 자서전적 기억이 기록하는 정보들 중 과거의 사건들을 회상하는데 가장 효과적인 정보가 무엇인지 도출하고, 이를 이용한 사진 색인 및 검색 시스템의 개발을 위해 수행되어야 할 연구 과제들을 제시하였다.

DDPG 알고리즘을 이용한 양팔 매니퓰레이터의 협동작업 경로상의 특이점 회피 경로 계획

이종학(Jonghak Lee),김경수(Kyeongsoo Kim),김윤재(Yunjae Kim),이장명(Jangmyung Lee) 한국로봇학회(논문지) 2021 로봇학회 논문지 Vol.16 No.2

진단방사선영역에서 방사선장치의 이용실태 및 환자피폭선량에 관한 조사연구

김유현,최종학,김성수,이창엽,조평곤,이영배,김철민,Kim Youhyun,Choi Jonghak,Kim Sungsoo,Lee Chanhyeup,Cho Pyongkon,Lee Youngbae,Kim Chelmin 한국의학물리학회 2005 의학물리 Vol.16 No.1

IAEA는 영상의 질에 영향을 주지 않는 범위에서 피부흡수선량의 기준선량을 제시하였다. 이러한 개념은 점차적으로 국제적인 기준으로 사용하게 되었다. 이 기준선량은 강제사항이 아니며 권고사항이지만 방사선촬영에서 아주 훌륭한 기준이 된다. 그러나 IAEA에서 제공한 선량기준은 서양 사람을 기준으로 개발된 것이어서 우리나라 사람에게는 맞지 않고, 상대적으로 우리나라의 환자선량은 적으리라 예상된다. 따라서 방사선촬영 시 촬영부위에 따른 환자 피폭선량에 대한 기준을 따로 개발해야 할 필요가 있다. 본 연구팀은 병원협회에 등록되어 있는 종합병원 278개를 대상으로 환자 피폭에 대한 설문조사를 실시하였다. 설문회수율은 57.9%였으며 각 병원에서 답한 촬영조건을 기초로 NDD법을 이용하여 환자 피폭선량을 계산하였고 방사선장치의 이용현황을 분석한 결과는 다음과 같다 1) 방사선장치의 현황은 일반촬영장치가 42.0%, 투시촬영장치가 29.4%, 치과장치가 13.2%, CT 장치가 8.1% 그리고 유방촬영장치가 7.2%로 나타났다. 2) 방사선장치의 정류방식에 따른 분류는 삼상장치가 29.9%, 인버터장치가 29.5%, 단상장치가 25.5%, 콘덴서방식이 9.0% 그리고 무응답이 6.0%였다. 3) 방사선장치의 수광방식에 따른 분류는 F/S 방식이 46.8%, CR 방식이 26.6%, DR 방식이 17.7% 그리고 무응답이 8.9%로 나타났다. 4) 방사선 촬영건수는 흉부가 49.2%, 척추가 16.8% 그리고 복부가 12.7%순으로 나타났다. 5) 환자 피폭선량은 두부 전후방향촬영 2.23 mGy, 복부 전후방향촬영 3.20 mGy 그리고 흉부 후전방향촬영 0.28 mGy로 나타났다. IAEA's guidance levels have been provided for western people to the end. Guidance levels lower than the IAEA'S will be necessary in view of Korean people's proportions. Therefore, we need to develope the standard doses for Korean people. And we conducted a nationwide survey of patient dose from x-ray examinations in Korea. In this study, the 278 institutions were selected from Members Book of Korean Hospital Association. The valid response rate was approximately 57.9%. Doses were calculated from the questionnaires by NDD method. We obtained the results were as follows; 1) General radiographic equipments were distributed for 42.0%, fluoroscopic equipments 29.4%, dental equipments 13.2%, CT units 8.1 % and mamographic units 7.2%. 2) According to classification by rectification, three-phase equipments were 29.9%, inverter-type generators 29.5%, single-phase equipments 25.5%, constant voltage units 9.0% and unknown units 6.0%. 3) According to classification by receptor system, film-screen types were 46.8%, CR types 26.8%, DR types 17.7% and unknown types 8.9%. 4) The number of examinations were chest 49.2%, spine 16.8% and abdomen 12.7%. 5) Patient doses were head AP 3.44 mGy, abdomen AP 4.25 mGy and chest PA 0.39 mGy.