Edge-Limited Valley-Preserved Transport in Quasi-1D Constriction of Bilayer Graphene

Lee, Hyunwoo,Park, Geon-Hyoung,Park, Jinho,Lee, Gil-Ho,Watanabe, Kenji,Taniguchi, Takashi,Lee, Hu-Jong American Chemical Society 2018 NANO LETTERS Vol.18 No.9

<P>We investigated the quantization of the conductance of quasi-one-dimensional (quasi-1D) constrictions in high-mobility bilayer graphene (BLG) with different geometrical aspect ratios. Ultrashort (a few tens of nanometers long) constrictions were fabricated by applying an under-cut etching technique. Conductance was quantized in steps of ∼4<I>e</I><SUP>2</SUP>/<I>h</I> (∼2<I>e</I><SUP>2</SUP>/<I>h</I>) in devices with aspect ratios smaller (larger) than 1. We argue that scattering at the edges of a quasi-1D BLG constriction limits the intervalley scattering length, which causes valley-preserved (valley-broken) quantum transport in devices with aspect ratios smaller (larger) than 1. The subband energy levels, analyzed in terms of the bias-voltage and temperature dependences of the quantized conductance, indicated that they corresponded well to the effective channel width of a physically defined conducting channel with a hard-wall confining potential. Our study in ultrashort high-mobility BLG nano constrictions with physically tailored edges clearly confirms that physical edges are the major source of intervalley scattering in graphene in the ballistic limit.</P> [FIG OMISSION]</BR>

Surveillance of Mosquitoes Associated with Vector Born Disease

Hyunwoo Kim,Su-Bum Lee,Wook-Gyo Lee,Kyu Sik Chang,Jong Yul Roh,Hyung-Woo Lim,Sung Chan Yang,Seong Yoon Kim,Hak Seon Lee,Hye mi Yu,Young-Ran Ju,E-Hyun Shin 한국응용곤충학회 2015 한국응용곤충학회 학술대회논문집 Vol.2015 No.10

There are over 3,000 different species of mosquitoes throughout the world; currently 56 species are reported in Korea. Mosquitoes can act as vectors for many disease-causing viruses and parasites during blood sucking. Various species of mosquitoes are estimated to transmit various types of disease to more than 700 million people annually in Africa, South America, Central America, Mexico, Russia, and much of Asia, with millions of resultant deaths. At least two million people annually die of these diseases, and the morbidity rates are many times higher still. To prevent the spread of diseases, KNIH (Korea National Institute of Health) used three categorized methods; identifying or taxonomic analysis of mosquitoes, detecting virus caring mosquitoes, and detecting malaria from Anopheline mosquitoes. We have proved that taxonomic analysis using DNA barcording method (COI gene) is useful to complement identification of mosquito species. In detecting virus, we have reported Cx. orientalis as a new potential Japanese encephalitis virus (JEV) vector. We also reported that the Anopheline mosquito species composition and Plasmodium vivax infection rates in malaria hot spot in Korea.

Proinsulin Shares a Motif with Interleukin-1α (IL-1α) and Induces Inflammatory Cytokine via Interleukin-1 Receptor 1

Lee, Siyoung,Kim, Eunsom,Jhun, Hyunjhung,Hong, Jaewoo,Kwak, Areum,Jo, Seunghyun,Bae, Suyoung,Lee, Jongho,Kim, Busun,Lee, Jungmin,Youn, Sulah,Kim, Somi,Kim, Miyeon,Kim, Hyunwoo,Lee, Youngmin,Choi, Dong American Society for Biochemistry and Molecular Bi 2016 The Journal of biological chemistry Vol.291 No.28

<P>Although it has been established that diabetes increases susceptibility to infections, the role of insulin (INS) in the immune response is unknown. Here, we investigated the immunological function of INS. Proinsulin dimer (pINSd) was a potent immune stimulus that induced inflammatory cytokines, but mature INS was unable to induce an immune response. An affinity-purified rabbit polyclonal antibody raised against mature IL-1α recognized IL-1α and pINS but failed to detect mature INS and IL-1β. Analysis of the pINS sequence revealed the existence of an INS/IL-1α motif in the C-peptide of pINS. Surprisingly, the INS/IL-1α motif was recognized by monoclonal antibody raised against IL-1α. Deleting the INS/IL-1α motif in pINSd and IL-1α changed their activities. To investigate the pINSd receptor, the reconstitution of IL-1 receptor 1 (IL-1R1) in Wish cells restored pINSd activity that was reversed by an IL-1R antagonist. These data suggested that pINSd needs IL-1R1 for inflammatory cytokine induction. Mouse embryo fibroblast cells of IL-1R1-deficient mice further confirmed that pINSd promotes immune responses through IL-1R1.</P>

Atomic layer deposition growth of SnS₂ films on diluted buffered oxide etchant solution-treated substrate

Lee, Namgue,Lee, Gunwoo,Choi, Hyeongsu,Park, Hyunwoo,Choi, Yeonsik,Kim, Keunsik,Choi, Yeongtae,Kim, Jong-Woo,Yuk, Hyunwoo,Sul, Onejae,Lee, Seung-Beck,Jeon, Hyeongtag Elsevier BV * North-Holland 2019 Applied Surface Science Vol.496 No.-

<P><B>Abstract</B></P> <P>In this report, two types of substrates were prepared for deposition of few-layer tin disulfide (SnS<SUB>2</SUB>) via atomic layer deposition (ALD). The first substrate was prepared using a conventional cleaning method, while the second substrate was rinsed with buffered oxide etcher (BOE) solution after conventional cleaning. Changes in the substrate were confirmed by X-ray photoelectron spectroscopy, contact angle measurements, and electron spin resonance. Characteristics of the SnS<SUB>2</SUB> thin films were determined by X-ray diffraction, Raman analysis, Fourier transform-infrared spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. To investigate growth rate, thickness was measured as a function of ALD cycle number by atomic force microscopy, and 2D layered structure was confirmed by transmission electron microscopy. Findings confirmed that surface treatment using BOE solution was related to an increased growth rate during the initial ALD process. Finally, back-gate field effect transistors based on ALD-grown SnS<SUB>2</SUB> film prepared on substrate that received diluted-BOE surface treatment showed marginal improvement in current on/off ratio from 2.9 × 10<SUP>5</SUP> to 6.5 × 10<SUP>5</SUP> and mobility from 0.22 cm<SUP>2</SUP>/Vs to 0.31 cm<SUP>2</SUP>/Vs compared to ALD-grown SnS<SUB>2</SUB> film prepared on bare substrate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SnS<SUB>2</SUB> thin films were grown by atomic layer deposition. </LI> <LI> Bare and surface treated substrates were used to deposit SnS<SUB>2</SUB>. </LI> <LI> Buffered oxide etchant solution was used to surface treatment. </LI> <LI> Hydrophilicity of two different substrates was investigated. </LI> <LI> Growth rate and transport properties of SnS<SUB>2</SUB> thin films were investigated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Traveling-wave antenna for the current drive using the fast wave in the lower hybrid-frequency range in the Versatile Experiment Spherical Torus (VEST)

Lee, Hyunwoo,Kim, Sunho,Jung, Seungho,Jo, Jonggab,Lee, Hyunyoung,Hwang, Yongseok,Lee, Byungje Elsevier 2018 Fusion engineering and design Vol.136 No.2

<P><B>Abstract</B></P> <P>An antenna using the fast wave in the lower hybrid-resonance frequency range is proposed for the significant attainment of the heating and current-drive efficiencies. For the operational stability regarding the change of the plasma load, the proposed antenna is designed as the combline-structure traveling-wave antenna. It consists of two tapered coaxial cables, two exciting straps of the folded-monopole structure, 12 radiating straps, 11 field isolators, and the Faraday shield. Regarding the vacuum load, the simulated and measured results show the wide impedance bandwidth (45 MHz, VSWR < 2) of the proposed antenna in conjunction with the traveling-wave-antenna structure and the folded-monopole exciting strap. Regarding the plasma load, the simulated results show that the proposed antenna provides the impedance bandwidth (35 MHz, VSWR < 2), and the fast wave is coupled with an input power from 51.5 − 90%. The measured and simulated coupling efficiencies are highly compatible in the Versatile Experiment Spherical Torus (VEST). According to the frequency-range changes, the simulated-variable range of the parallel refractive index (n<SUB>||</SUB>) is from 3 − 4.5 in the operational frequency band of 475–510 MHz.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The development of an efficient external-current-drive device is required. </LI> <LI> The Lower Hybrid Fast Wave can propagate into central region in higher-density plasma. </LI> <LI> The combline-type traveling-wave antenna (TWA) is proposed for the heating and current-drive efficiencies. </LI> <LI> The coupling research between the antenna and simulated plasma model is carried out. </LI> <LI> The simulation and experiment results are compared regarding the coupling efficiency. </LI> </UL> </P>

UWB 기반 실내 내비게이션 앱 개발

유현우 ( Hyunwoo You ),이정균 ( Jungkyun Lee ),남소미 ( Somi Nam ),이주연 ( Juyeon Lee ),이윤서 ( Yoonseo Lee ),김민성 ( Minsung Kim ),이영찬 ( Youngchan Lee ),민홍 ( Hong Min ) 한국정보처리학회 2023 한국정보처리학회 학술대회논문집 Vol.30 No.2

실내 내비게이션 기술은 시설물 구조에 익숙하지 않은 방문자의 길 안내뿐만 아니라 무인 이동체들의 위치를 파악하는 데 중요한 역할을 한다. 본 논문에서는 UWB 기술을 활용하여 타깃 영역 안에서의 좌표를 추출하고 이를 활용하여 길 안내를 해주는 앱을 개발하였다. 개발된 앱은 보정 기법을 통해 사용자의 실제 위치와 지도 위에 표시되는 위치 사이의 오차를 최소화하였다.

Considerations for Web of Object Service Architecture on IoT Environment

NamKyung Lee,HyunWoo Lee,Won Ryu 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.1

The internet is an optimal place to human as a producer or a consumer for sharing information until now. In the future, not only the human-generated information but also things will be connected into internet and these will evolve into internet of things(IoT) which can share the information thing-in-itself and its environment. Firstly, this paper proposes a service architecture which includes various devices for providing web base IoT services. Secondly, this paper also proposes a service platform which supports service orchestration and composition with device objectification and finally describes structure and functionalities of web of object gateway.

신뢰성분석 기법을 이용한 고속철도 검측시스템의 수명예측

이현우(Hyunwoo Lee),이병곤(Byeong-Gon Lee),이충한(Chunghan Lee) 한국신뢰성학회 2014 신뢰성응용연구 Vol.14 No.3

The importance of railway safety has become increasingly significant domestically as well as internationally, as a series of high speed railway accidents and other major accidents have occurred recently. Especially for the domestic railway, the Korean Railway Safety Law has been revised recently, mandates all the domestic railway operation authorities to render the performance of RAMS and RCM. This study inspects and analyzes the current status of the sensing technology of the electric detection system to tell the status of railway facilities in the highway railway in a real time through a sensor. It also performs the reliability analysis of the electric detection system that is being progressed as a study assignment and suggests the system construction for the higher reliability.

목표 힘 수준에 따른 양손 힘 조절 능력의 변화

이형우 ( Lee Hyunwoo ),염승혁 ( Yeom Seunghyeok ),정형도 ( Jung Hyeongdo ),조혜민 ( Cho Hyemin ),박기웅 ( Park Kiwoong ),박신영 ( Park Shinyoung ),이한얼 ( Lee Hanall ),이태리 ( Lee Talee ),윤희정 ( Yoon Heejeong ),지민제 ( Ji Min 인천대학교 스포츠과학연구소 2021 스포츠科學硏究誌 Vol.34 No.0

본 연구는 서로 다른 목표 힘 수준에 따른 양손 힘 조절 과제 시 힘 조절 능력의 변화 패턴을 시도 내 분석과 시도 간 분석을 통해 평가하고자 하였다. 건강한 성인 11명이 연구에 참여하였으며, 이들은 개인의 최대 자발적 수축의 10% 및 60%의 힘 조절목표를 제시받아 20초 동안 목표 힘 수준에 최대한 머무르는 과제를 실시하였다. 본 연구에서 분석한 시도 내 분석의 변인은 힘의 오차, 가변성, 규칙성, 협응력이고, 시도 간 분석 변인으로는 비제어 다양체 분석을 사용하여 시도 간의 양손 협응력을 평가하였다. 변인의 측정과 분석을 위해 등척성 잡기 힘 조절 장비를 사용하였다. 본 연구의 통계처리는 대응 표본 t-검정을 통해 분석하였으며, 시도 내의 변인과 시도 간 변인의 관계성을 분석하기 위해 피어슨 선형 상관관계 분석을 수행하였다. 연구 결과, 목표 힘 수준이 높아졌을 때 힘의 오차, 가변성 및 규칙성은 증가하였다. 양손 힘 협응력은 반대 위상에서 동일 위상 협응 패턴으로 전환되었고 시도 간 운동 시너지가 감소되었다. 상관 관계분석에서 양측 운동 시너지 와 힘의 오차 및 가변성이 유의한 음의 상관관계가 나타났다. This study aimed to evaluate the pattern of change in the force control capability during bimanual force control task with different targeted force levels through within and between-trial analysis. 11 healthy adults who had no disorders in musculoskeletal and nervous system were recruited to perform bimanual force control task. Subjects measured maximal voluntary contraction(MVC), and perfomed tasks of sustaining at targeted force level at 10% and 60% of individual MVC. Variables in the within a trial analysis were force error, variability, regularity, and coordination. Additionally, our study examined bilateral motor synergies by conducting uncontrolled manifold(UCM) analysis. Isometric grip force control device was used to measure force outputs. The data analysis was performed using the Matlab program (Math Works TM Inc., Natick, USA). For the statistical analysis, the paired t-test and Pearson's linear correlation analysis were performed to analyze the relationship between variables from within and between trials by using SPSS 25.0 for Windows. The findings revealed that force error, variability and regularity was increased when the higher targeted force level was provided. Additionally, bilateral force coordination showed that force exertions between two hands were shifted anti-phase to in-phase force pattern. In the correlation analysis, decreased bilateral motor synergy was significantly related to greater values in force error and variability.

국내ㆍ외 자동차 실내공기질 관련 연구 동향

이현우(Hyunwoo Lee),최영태(Youngtae Choi),이광범(Kwangbum Lee),이정기(Jeongki Lee),김광일(Kwangil Kim),이정화(Jeongwha Lee),임종순(Jongsoon Lim),신영복(Youngbok Sin) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

All across our nation, people live, work, and learn in indoor environments and especially, many people spend more time than ever before inside of cars. Recent years have been increasing attention focused on the air contamination inside auto-cabin. The sources of air contamination inside auto-cabin are roughly divided into internal sources(ex. chemical compounds from interior material) and external sources(ex. tail-pipe emission etc.). The Purpose of this research is to examine the status of worldwide auto-cabin air quality study, and to give the information when research is intended to develop methods to mitigate indoor air problem from auto-cabin.