Cu+-incorporated TiO2 overlayer on Cu2O nanowire photocathodes for enhanced photoelectrochemical conversion of CO2 to methanol

Lee, Kangha,Lee, Seokwon,Cho, Hyunjin,Jeong, Sunil,Kim, Whi Dong,Lee, Sooho,Lee, Doh C. Elsevier Inc 2018 Journal of Energy Chemistry Vol.27 No.1

Highly Efficient and Highly Conductive Phosphor-in-Glass Materials for Use in LD-Driven White-Light Lamp

Lee, Dong-Ho,Kim, Sunil,Kim, Hyungsun,Lee, Sun-Kyu SPRINGER 2019 INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND Vol. No.

Robust Video Fingerprinting Based on Symmetric Pairwise Boosting

Sunil Lee,Yoo, C.D.,Kalker, T. IEEE 2009 IEEE transactions on circuits and systems for vide Vol.19 No.9

<P>This paper proposes a video fingerprinting method based on a novel binary fingerprint obtained using a feature selection algorithm called the symmetric pairwise boosting (SPB). The binary fingerprints are obtained by filtering and quantizing perceptually significant features extracted from an input video clip. The SPB algorithm, which is a generalization of the conventional asymmetric pairwise boosting (APB), selects appropriate filters and quantizers from a class of candidate filters and quantizers in such a way that perceptually similar and dissimilar pairs of video clips are correctly classified as matching and non-matching pairs, respectively. The binary form of the novel fingerprint makes it conducive to an efficient database search, and the experimental results show that the proposed method outperforms the APB-based video fingerprinting methods in terms of both robustness and discriminability.</P>

Selective CO adsorption using sulfur-doped Ni supported by petroleum-based activated carbon

Sunil Kwon,Youngwoo You,Hyungseob Lim,Jinhee Lee,Tae-Sun Chang,Yejin Kim,Hyunjoo Lee,Beom-Sik Kim 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.83 No.-

Carbon monoxide (CO) is an important platform compound that can be transformed into variousfinechemicals. However, CO manufactured by the conventional methods contains many other gases such ashydrogen, methane, nitrogen and carbon dioxide, and additional separation processes are required toutilize CO as a raw material. The current state-of-the-art techniques for separating CO have problems ofhigh energy consumptions. There are needs for an alternate separation process. In this work, wedeveloped a Ni-based adsorbent supported by petroleum-based activated carbon (PAC, BET > 1300 m2/g). The affinity and capacity for CO were evaluated by CO isotherm and CO temperature-programmeddesorption. The selectivity to CO was evaluated by the breakthrough test of multicomponent gases (10%H2, 10% CO, 1% CH4, and 1% CO2 with He balance). Ni/PAC was doped with sulfur to increase the COadsorption activity, and the sulfur-doped Ni/PAC (Ni/PACS) showed outstanding CO adsorption capacity,which is 9 times higher than that of the sulfur-free Ni/carbon adsorbent (Ni/PAC). The Ni/PACS couldrecover the CO to over 99% purity from the multicomponent gases. The sulfur-doped Ni/carbon adsorbentshowed high affinity, high capacity, and high selectivity for CO separation.

Reversible Image Watermarking Based on Integer-to-Integer Wavelet Transform

Sunil Lee,Yoo, C.D.,Kalker, T. IEEE 2007 IEEE transactions on information forensics and sec Vol.2 No.3

<P>This paper proposes a high capacity reversible image watermarking scheme based on integer-to-integer wavelet transforms. The proposed scheme divides an input image into nonoverlapping blocks and embeds a watermark into the high-frequency wavelet coefficients of each block. The conditions to avoid both underflow and overflow in the spatial domain are derived for an arbitrary wavelet and block size. The payload to be embedded includes not only messages but also side information used to reconstruct the exact original image. To minimize the mean-squared distortion between the original and the watermarked images given a payload, the watermark is adaptively embedded into the image. The experimental results show that the proposed scheme achieves higher embedding capacity while maintaining distortion at a lower level than the existing reversible watermarking schemes.</P>

Study on the Effect of Pressurizer Cutting Scenario

Hakyun Lee,Sunil Kim,Minho Lee,Jongsoon Song 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1

When a permanently-closed nuclear power plant is to be decommissioned, large structures targeted to be cut in the process include a steam generator, reactor, and reactor coolant pump (RCP). Although there are sufficient preliminary studies being done on these structures to assess the radiation exposure dose, relatively fewer studies are underway regarding pressurizers. Therefore, preliminary evaluations are required to prevent workers from being overexposed to radiation coming from a pressurizer and to avoid an unnecessary increase in the decommissioning cost. This study created a cutting scenario based on disposal drums for solid radioactive wastes. The cutting scenario was based on 200-liter and 320-liter drums for solid wastes and on the assumption that all cutting operations were done 100 centimeters away from the structure to be cut. When are cutting process of a Pressurizer is carried out per scenario, the 200-liter drum produces 272 pieces, whereas the 320-liter counterpart generates 234 pieces. Given that South Korea allocates 75,550 KRW per liter (based on 200 L) for the disposal cost, an increase in the number of drums leads to an exponential growth of the decommissioning cost, which fuels the need to establish more organized cutting strategies. Meanwhile, in terms of radiation dose, plasma, laser, and flame cutting techniques were estimated to record 0.232 mSv, 0.299 mSv, and 0.213 mSv respectively for 200 L, and 0.195 mSv, 0.251 mSv, and 0.179 mSv respectively for 320 L (based on DF-90). When compared with the annual dose limit of 100 mSv (0.0057 mSv·hr?1), the above numbers registered for both 200 L and 320 L were estimated to satisfy the dose limit, with only a negligible difference in the dose between the two capacities. The results generated from this study are expected to be utilized as a meaningful basis to identify applicable cutting techniques of a pressurizer as part of the decommissioning operation and to establish its cutting plans in compliance with ALARA.

개방수조형 연구용 원자로의 노심 열출력에 관한 연구

이선일(Sunil Lee),서경우(Kyoung-Woo Seo) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.5

가압 경수로용 종합 효과 시험 장치를 위한 이차 계통의 개념 설계

이선일(Sunil Lee),류성욱(Sung Uk Ryu),박현식(Hyun Sik Park) 대한기계학회 2019 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.7 No.2

국내에서 연구 중인 표준 원전은 안전성 및 성능을 검증해야 하며, 이를 위해 기기 및 계통 기반의 시험인 개발 효과 시험(SET: Separate Effect Test)을 포함하여 모든 계통을 포함하는 종합 효과 시험(IET: Integral Effect Test)이 수행되고 있다. IET 장치의 경우, 시험의 용이성을 고려해 원자로를 포함하는 일차 계통, 터빈을 포함하는 이차 계통, 안전을 위한 다양한 안전 계통, 그리고 여러 보조 계통들을 모두 축소 모형하여 구성된다. 실제 전기 생산을 위한 이차 계통은 발전 사이클(랭킨 사이클, Rankine Cycle)을 열역학적 기초로 두고 있으며, IET에서는 발전 사이클을 구성하지 않고 일차 계통의 경계 조건만을 만족시키는 역할을 수행하게 설계되고 있다. 이런 IET의 이차 계통은 크게 열린계 방식(open system type)과 닫힌계 방식(closed system type)으로 나누어진다. 두 가지 방식 중 본 논문에서는 일반적으로 사용되는 가압 경수로용 IET 장치의 이차 계통인 열린계 방식의 설계 과정에 대해서 설계 요건, 설계 개요, 주요 기능, 기술 사양으로 나누어 자세히 소개하고자 한다. Standard nuclear power plants under studying in Korea should verify the safety and performance of the systems and components. For this purpose, integral effect tests including all systems in power plant are being conducted, including the separate effect tests, which are a component or a system-based tests. In the case of the IET, the primary system including the reactor, the secondary system including the turbine, the various safety systems, and various auxiliary systems are scaled down for ease of testing. The secondary system for the actual electricity production is based on the thermodynamic basis of the power generation cycle (Rankin cycle), and IET is designed to fulfill the boundary conditions of the primary system without consisting the power generation cycle. This secondary system for IET is largely divided into open-system type and closed-system type. In this paper, the design process for the open-system type, which is the secondary system of commonly used in IET for the pressurized water reactor, is described in detail by dividing into design overview, design requirements, main functions, and technical specifications.

개방수조형 연구용 원자로에서 일차냉각계통의 설계

이선일(Sunil Lee),서경우(Kyoung Woo Seo) 대한기계학회 2018 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.6 No.2

고온 고압조건을 가진 발전용 상업로와는 달리 저온 저압조건에서 작동되는 연구용 원자로는 일반적으로 핵반응이 발생하는 노심이 개방된 수조수에 담겨 있는 개방수조형 방식으로 설계된다. 이 수조수의 냉각 및 정화를 위해 일차냉각계통을 포함한 다양한 유체계통이 필요하다. 특히 일차냉각계통은 정상출력운전 중 노심에서 발생되는 열을 일차냉각계통 펌프와 열교환기를 이용하여 제거하는 역할을 한다. 일차냉각계통 펌프가 정지되면 일차냉각계통 펌프의 관성바퀴에 의한 관성서행 유량을 통해 노심냉각을 유지하고, 안전잔열제거계통 펌프를 정지하면 플랩밸브를 통한 수조수의 자연순환에 의해 노심붕괴열이 제거된다. 본 논문에서는 개방수조형 연구용 원자로의 노심 냉각을 위한 일차냉각계통에 대해서 설계요건, 계통설명, 계통 운전(기동, 출력운전, 원자로 정지), 설계평가, 검사 및 시험의 항목으로 나누어 자세히 기술하였다. Unlike the nuclear power reactor, the research reactor for the multi-purpose neutron application has been designed with the open-pool type reactor the core is submerged in. The research reactor has several fluid systems such as primary cooling system (PCS), secondary cooling system, pool water management system, and hot water layer system. The primary cooling system removes the fission heat from the core in the normal operation. When the PCS pumps are not in operation after the reactor shutdown or trip, PCS removes the core decay heat by natural circulation through the flap valve. In this paper, the design bases, system description, system operation, design evaluation, inspection and testing for the primary cooling system are specified in detail.

PTK7⁺ Mononuclear Cells Express VEGFR2 and Contribute to Vascular Stabilization by Upregulating Angiopoietin-1

Chauhan, Sunil K.,Lee, Hyung Keun,Lee, Hyun Soo,Park, Eun Young,Jeong, Eunae,Dana, Reza American Heart Association, Inc. 2015 Arteriosclerosis, thrombosis, and vascular biology Vol.35 No.7

<P><B>Objective—</B></P><P>In angiogenesis, circulating mononuclear cells are recruited to vascular lesions; however, the underlying mechanisms are poorly understood.</P><P><B>Approach and Results—</B></P><P>Here, we characterize the functional role of protein tyrosine kinase 7 (PTK7)–expressing CD11b<SUP>+</SUP> mononuclear cells in vitro and in vivo using a mouse model of angiogenesis. Although the frequencies of PTK7<SUP>+</SUP>CD11b<SUP>+</SUP> cells in the bone marrow remained similar after vascular endothelial growth factor-A–induced neovascularization, we observed an 11-fold increase in the cornea. Importantly, vascular endothelial growth factor-A–induced chemotaxis of PTK7<SUP>+</SUP> cells was mediated by vascular endothelial growth factor receptor 2. In a coculture with endothelial cells, PTK7<SUP>+</SUP>CD11b<SUP>+</SUP> cells stabilized the vascular network for 2 weeks by expressing high levels of angiopoietin-1. The enhanced vascular stability was abolished by knockdown of angiopoietin-1 in PTK7<SUP>+</SUP>CD11b<SUP>+</SUP> cells and could be restored by angiopoietin-1 treatment.</P><P><B>Conclusions—</B></P><P>We conclude that PTK7 expression in perivascular mononuclear cells induces vascular endothelial growth factor receptor 2 and angiopoietin-1 expression and thus contributes to vascular stabilization in angiogenesis.</P>