Encapsulation of a Monolayer WSe₂ Phototransistor with Hydrothermally Grown ZnO Nanorods

Lee, Kang-Nyeoung,Bang, Seungho,Duong, Ngoc Thanh,Yun, Seok Joon,Park, Dae Young,Lee, Juchan,Choi, Young Chul,Jeong, Mun Seok American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.22

<P>Transition metal dichalcogenides (TMDCs) are promising two-dimensional (2D) materials for realizing next-generation electronics and optoelectronics with attractive physical properties. However, monolayer TMDCs (<SUP>1L</SUP>TMDCs) have various serious issues, such as instability under ambient conditions and low optical quantum yield from their extremely thin thickness of ∼0.7 nm. To overcome these issues, we constructed a hybrid structure (HS) by growing zinc oxide nanorods (ZnO NRs) on a monolayer tungsten diselenide (<SUP>1L</SUP>WSe<SUB>2</SUB>) using the hydrothermal method. Consequently, we confirmed not only enhanced photoluminescence of <SUP>1L</SUP>WSe<SUB>2</SUB> but also improved optoelectronic properties by fabricating the HS phototransistor. Through various investigations, we found that these phenomena were due to the antenna and p-type doping effects attributed to the ZnO NRs. In addition, we verified that the optoelectronic properties of <SUP>1L</SUP>TMDCs are maintained for 2 weeks in ambient condition through the sustainable encapsulation effect induced by our HS. This encapsulation method with inorganic materials is expected to be applied to improve the stability and performance of various emerging 2D material-based devices.</P> [FIG OMISSION]</BR>

대한민국 지역간 항공교통 (RAM) 운영을 위한 시장 경쟁력 분석

이주찬(Juchan Lee),김슬기(Seulki Kim),김정현(Junghyun Kim) 항공우주시스템공학회 2023 항공우주시스템공학회 학술대회 발표집 Vol.2023 No.10

투과도 조절기능이 포함 된 PDLC 전원 공급 장치 개발

이주찬(Juchan Lee),이진우(Jin-woo Lee),목형수(Hyung soo Mok) 전력전자학회 2018 전력전자학술대회 논문집 Vol.2018 No.11

전압가변에 의한 PDLC 필름 투과도에 대한 연구

이주찬(Juchan Lee),목형수(Hyung soo Mok),이진우(Jin-woo Lee) 전력전자학회 2018 전력전자학술대회 논문집 Vol.2018 No.7

전류 패턴의 설계가 가능한 SOA Dimming Driver에 관한 연구

이주찬(Juchan Lee),엄진섭(Jinseob Eom) 한국조명·전기설비학회 2013 조명·전기설비학회논문지 Vol.27 No.2

In this paper, the low cost SOA Dimming Driver which consisted of LabVIEW programming part capable of current pattern design, DAQ module for analog voltage output, and voltage to current converter has realized. The output current(possible to 3A) from the Driver was clearly constant without ripple and also showed no variance until 1mA unit for a long time operation. The proposed low cost Driver can replace the previous high cost SOA Drivers for wavelength swept lasers fully and provide the convenience and safety of auto-supplying a designed current pattern.

NiFe₂O₄/MXene Nanoparticle via High Energy Ball Milling for Anion Exchange Membrane Seawater Water Electrolyzer

Kyung-Bok Lee,Yeongdae Lee,Ki-Yong Yoon,Jae-Yeop Jeong,Hyun-Kon Song,Juchan Yang 한국표면공학회 2023 한국표면공학회 학술발표회 초록집 Vol.2023 No.11-1

Conductivity‐Dependent Completion of Oxygen Reduction on Oxide Catalysts

Lee, Dong‐,Gyu,Gwon, Ohhun,Park, Han‐,Saem,Kim, Su Hwan,Yang, Juchan,Kwak, Sang Kyu,Kim, Guntae,Song, Hyun‐,Kon WILEY‐VCH Verlag 2015 Angewandte Chemie Vol.54 No.52

<P><B>Abstract</B></P><P>The electric conductivity‐dependence of the number of electrons transferred during the oxygen reduction reaction is presented. Intensive properties, such as the number of electrons transferred, are difficult to be considered conductivity‐dependent. Four different perovskite oxide catalysts of different conductivities were investigated with varying carbon contents. More conductive environments surrounding active sites, achieved by more conductive catalysts (providing internal electric pathways) or higher carbon content (providing external electric pathways), resulted in higher number of electrons transferred toward more complete 4e reduction of oxygen, and also changed the rate‐determining steps from two‐step 2e process to a single‐step 1e process. Experimental evidence of the conductivity dependency was described by a microscopic ohmic polarization model based on effective potential localized nearby the active sites.</P>

의원입법에 대한 규제영향분석의 필요성 연구

이혁우(Lee, Hyukwoo),김주찬(Kim, Juchan),김태윤(Kim, Tae-Yun),여차민(Yuh, Cha-Min) 한국경제연구원 2011 규제연구 Vol.20 No.1

우리나라의 의원입법은 정부입법과는 달리 체계화된 규제영향분석 제도를 갖추고 있지 못하다. 더구나 본 논문에서 분석한 것처럼 기존 국회의 법안 검토 및 분석 제도는 정부의 규제영향분석만큼 정교하지 못하다. 의원입법으로 성립되는 규제 법안의 사회적 영향에 대한 체계적이고 깊이 있는 분석이 이루어지지 못하고 있어 규제품질관리에 허점이 존재하고 있는 것이다. 상임위원회 전문위원의 의안검토보고는 지침에서 제시된 내용과는 달리 표준화 수준이 매우 낮을 뿐만 아니라 형식적으로 운영되고 있으며 예산정책처의 비용추계는 체계성이 높지만 평가대상 및 분석항목이 재정소요에 대한 비용추계에 국한되고 있어 사회적 영향을 고려하는 규제영향분석을 적극적으로 실시하기에는 어려움이 있었다. 법제사법위원회의 체계 및 자구심사는 법안에 대한 형식적 분석에 치중하고 있었다. 그리고 입법조사처의 입법조사분석은 국회의원의 다양한 입법분석 수요에 부응하는 제도의 성격상 규제영향분석과 같이 체계화된 지표를 가지고 표준화된 분석을 시도하는 것이 어렵다. 이런 연구결과로부터 향후 의원입법의 품질을 제고하기 위해서는 의원입법에 대해서도 해당 입법안이 사회 전반에 미칠 편익과 비용을 포괄적으로 분석하는 규제영향분석 제도를 도입할 필요성이 있음을 알 수 있다. This study intends to insist on the necessity of Regulatory Impact Analysis to the Assembly-introduced Bills which have been exempted from a detailed social benefit/cost analysis in Korea. With the various monitoring systems of Korean National Assembly like Legislation and Judiciary Committee, NABO(national assembly budget office), NARS(national assembly research service), We could not judge sufficiently whether the Bills bring to benefits over the costs to the society. Because these existed monitoring institutions does not adopt the logics of regulatory impact analysis which is useful to analyze costs and benefits of Bills. So, The growing number of bills introduced by assembly which are exempt from the regulatory quality process could be remedied by a permanent monitoring tools like Regulatory Impact Analysis in the National Assembly to assure oversight of the quality of laws.

자기적합성선언제도 도입방안에 관한 연구

김주찬(Juchan Kim),이혜영(Hye Young Lee),최성락(Seong Rak Choi) 한국공공관리학회 2008 한국공공관리학보 Vol.22 No.2

우리나라에서는 2,300개 이상의 품목에 대하여 강제인증 제도가 시행되고 있는데, 시장의 자율성과 효율성을 증대하고 정책 품질을 제고하기 위하여 자기적합성 선언 제도를 도입하고자 하는 논의가 이루어지고 있다. 그런데 자기적합성 선언제도 도입과 관련하여 그 필요성을 주장하는 논의는 많이 이루어지고 있으나, 현재 강제인증제도가 시행되고 있는 품목들 중에서 어떤 품목들에 대하여 적합성 선언제도가 도입될 수 있는가에 대한 논의는 거의 이루어지고 있지 못하다. 따라서 본 연구에서는 73개 대표 품목에 대한 전문가 설문조사 및 그 결과의 유형화를 통하여, 어떠한 품목 유형에 대하여 적합성 선언제도 도입이 가능한가에 대한 시사점을 얻고자 하였다. 전문가 설문조사 및 그 결과에 대한 군집 분석 결과, 현재 적합성 선언제도가 시행되고 있는 품목과 같은 군집에 속하는 품목들은 적합성 선언제도 도입이 가능한 것으로 조사되었다. 또한 적합성 선언제도 도입과 관련하여 가장 중요한 요인은 위험 요인과 소비자의 지지로 조사되었다. 그리고 품목의 성질에 따라 공인 시험기관을 필요로 하지 않는 완전한 자율규제 형식의 적합성 선언제도 도입의 가능성도 유추될 수 있었다. 본 연구는 연구결과의 일반화에 어느 정도 한계가 있지만, 강제인증 대상 품목과 적합성 선언 제도 도입 품목을 구분하는 분류 기준과 방법론을 제시하였다는 점에서 연구의 시사점이 있다. Currently, Korea is practicing enforcement certification system on over 2,300 products and services. A discussion to adopt SDoC is taking place in order to increase the autonomy and efficiency of the market and to improve the quality of policy. While a discussion stressing the need of adopting SDoC is taking place actively, it hasn’t been discussed that to which method can be applied to adopt SDOC . Therefore, this article aims to draw some implications regarding to which types of items SDoC can be applied by categorizing the survey result. According to the survey and cluster analysis of the survey result, the most important factors regarding adopting SDoC were proved to be risk factor and support from consumers. Although this research shows a certain limitation in terms of generalization, the implications of this research are that it presented the criteria and method to adopt SDoC.

Comparison Between Thermal Analysis Results With FVM and Sub-channel Codes in a Single Assembly Heat Transfer Test

Doyun Kim,Juchan Lee,Seunghwan Yu 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

Dry storage is a predominantly used method as a spent nuclear fuel storage system after spent nuclear fuel is cooled in the spent fuel pool. Spent nuclear fuel is highly radioactive and it generates heat called decay heat originated by fission products and radiation. Therefore, temperature of spent nuclear fuel should be predicted whether its cladding temperature is maintained under 400°C, which is the allowable temperature limit of cladding in a dry storage. ANSYS Fluent and COBRA-SFS are predominantly used computational method to investigate the temperature of spent nuclear fuels in a dry storage. Herein, thermal analysis results with the methods were compared based on a Single Assembly Heat Transfer Test, which is a heat test with an electrically heated model of a single PWR fuel assembly in a dry cask performed at the Pacific Northwest Laboratory. Decay heat was 1kW and backfill gas was air. Fix temperature boundary condition is applied to inner shell according to measured temperature. In case of peak cladding temperature (PCT), Fluent predicted 240–284°C, while COBRA-SFS gave 243–292°C. The discrepancy between the codes is under 2.5%. The location where PCT took place was 3.65 m from the bottom of the assembly in both results. However, temperature difference between the upper and lower region of the assembly based on the Fluent was smaller than the temperature difference based on the COBRA-SFS. It means the heat was well transferred in an axial direction with Fluent compared to COBRA-SFS. In lower plenum region where air was naturally circulated, COBRASFS had disadvantages compared to Fluent because it modeled the lower plenum by single node, so it was hard to simulate convection heat transfer by natural circulation. natural circulation speed of air in a center region of the assembly was 0.07–0.1 m·s?1 in both cases.