워터젯을 이용한 블라스팅 유리 마이크로 채널의 표면거칠기 개선

손성균(Sung-Gyun Son),한솔이(Sol-Yi Han),성인하(In-Ha Sung),김욱배(Wook-Bae Kim) 대한기계학회 2013 大韓機械學會論文集B Vol.37 No.12

파우더 블라스팅은 미세 유리가공법으로서 가공속도가 빠르고 저비용의 장점이 있지만 유리를 취성파괴 시키기 때문에 표면거칠기가 좋지않다. 블라스팅된 표면에 저압의 워터젯을 분사하여 표면에서의 연마 슬러리의 흐름을 통해 표면거칠기를 저감할 수 있다. 본 연구에서는 소다라임 유리에 블라스팅으로 마이크로 채널을 가공한 후 워터젯을 연속 적용하고, 마이크로 채널의 표면거칠기 및 단면 형상의 변화의 과정을 관찰하였다. 워터젯의 적용결과, 초기단계에서는 블라스팅에 의한 미세 요철이 제거되었고, 이후 표면하부의 크랙이 제거되어 평균 표면거칠기 50 nm 근방의 매끈한 표면을 얻을 수 있었다. 표면거칠기 저감에 동반하여 채널단면의 확장 과정도 함께 관측하였다. 마지막으로 제안한 방법에 의해 미세유체칩의 가공 결과를 제시하였다. Powder blasting, which is an efficient micromachining method for glass, silicon, and ceramics, has a critical disadvantage in that the surface finish is poor owing to the brittle fracture of materials. Low-pressure waterjet machining can be applied to smoothen the rough surface inside the blasted structure. In this study, the surface roughness and sectional dimension of micro-channels are observed during the repetitive application of a waterjet to blasted micro-channels. The asperities and subsurface cracks created by blasting are removed by waterjet machining. Along with the surface roughness, it is found that the sectional dimension increases and the edges of the finished microchannel become slightly round. Finally, a microfluidic chip is machined by the blasting-waterjet process and a transparent microfluidic channel is obtained efficiently.

스키 점프 선수의 공력 성능 및 자세 제어

이한솔(Hansol Yi),김우진(Woojin Kim),최해천(Haecheon Choi),이정일(Jungil Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

Control of the ski jumper’s posture is essential to achieve a longer flight distance. For this purpose, we conduct a large eddy simulation (LES) of turbulent flow past a model of a ski jumper which is obtained by 3D scanning the ski jumper’s body (Mr. Chil-Ku Kang, a member of the Korean national ski jump team). The angle of attack of the jump ski is 30° and the Reynolds number based on the length of the jump ski and the flight velocity is 540,000. The flow statistics including the drag and lift coefficients during the flight are in good agreements with our own experimental data. We investigate the flow characteristics such as the stagnation region, flow separation, and three-dimensional vortical structures and their effects on the drag, lift, and lift/drag. To find the optimal posture of the ski jumper, we build a simple geometric model of a ski jumper based on the result of LES where each part of the ski jumper’s body is modeled as a canonical bluff body such as a sphere, cylinder and flat plate. The drag and lift obtained from this approach are in good agreements with those from LES. Also, using this approach, the optimal posture for the best aerodynamic performance is to be found.

목표물 신호 모니터링 및 SPGD 알고리즘 기반 3 채널 타일형 결맞음 빔결합 시스템 연구

김영찬,윤영선,김한솔,장한별,박재덕,최윤진,나정균,이주한,강현구,여민수,최규홍,노영철,정윤찬,이혁재,유봉안,염동일,전창수,Kim, Youngchan,Yun, Youngsun,Kim, Hansol,Chang, Hanbyul,Park, Jaedeok,Choe, Yunjin,Na, Jeongkyun,Yi, Joohan,Kang, Hyungu,Yeo, Minsu 한국광학회 2021 한국광학회지 Vol.32 No.1

단일 레이저의 출력 한계를 뛰어넘기 위한 빔결합 방법으로서, 보강간섭 원리를 이용한 타일형 결맞음 빔결합 시스템에 대해 연구하였다. 와트급 출력의 3 채널 결맞음 광섬유 레이저 및 삼각형 배치의 팁-틸트(tip-tilt) 기능을 갖춘 3 채널 출력단을 자체제작 하였다. 모니터링 시스템, 위상제어기, 3 채널 위상변조기 간의 궤환 제어 시스템(closed-loop system)을 구성하고 SPGD 알고리즘을 적용하여, 위상잠금 속도 5~67 kHz, 이상적인 계산값 대비 중심부 광세기 효율 53.3%의 성공적인 3 채널 위상잠금을 구현하였다. 빔결합 소자가 필요 없고, 가장 고출력 가능성을 가진 타일형 결맞음 빔결합을 위한 요소기술 개발이 완료되어, 향후 다채널, 고출력, 고속 제어 연구로 이어질 수 있을 것으로 기대된다. We have studied a tiled-aperture coherent-beam-combining system based on constructive interference, as a way to overcome the power limitation of a single laser. A 1-watt-level, 3-channel coherent fiber laser and a 3-channel fiber array of triangular tiling with tip-tilt function were developed. A monitoring system, phase controller, and 3-channel phase modulator formed a closed-loop control system, and the SPGD algorithm was applied. Eventually, phase-locking with a rate of 5-67 kHz and peak-intensity efficiency comparable to the ideal case of 53.3% was successfully realized. We were able to develop the essential elements for a tiled-aperture coherent-beam-combining system that had the potential for highest output power without any beam-combining components, and a multichannel coherent-beam-combining system with higher output power and high speed is anticipated in the future.

Production of Functional Peptide with Anti-obesity Effect from Defatted Tenebrio molitor Larvae Using Proteolytic Enzyme

Youngju Song,구한솔,Jae Min Jo,Miran Shin,Song Yi Kim,감다혜,Sayaka Imamura,김진우 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.3

This study was conducted to investigate the antiobesity effect of peptides derived from defatted mealworm (Tenebrio molitor larvae) and to determine the expression level of obesity-related membrane-associated proteins in the rat muscle. The production of functional peptide was produced by hydrolysis of mealworm protein using commercial enzymes. To evaluate anti-obesity effects through animal feeding experiments, a total of thirty-two rats were randomly divided into control diet (CD), 5% mealworm peptide supplemented control diet (CT), highfat diet (HD), and 5% mealworm peptide supplemented high-fat diet group (HT). The weight loss of HT was confirmed by mealworm peptides feeding. The weights of fat tissues (perirenal and epididymal) of HT were significantly decreased, however, soleus muscle weight of HT was significantly increased compared to those of the HD, respectively. The expression levels of obesity-related membrane-associated proteins (FABPpm, PGC-1α, and PPAR) in HT group involved in fatty acid transport and utilization were significantly higher than that of the HD. From these results, mealworm peptide supplement showed an anti-obesity effect by stimulation of FABPpm, PGC-1α, and PPAR-δ in skeletal muscle and then showed an increase in muscle weight along with body weight loss in HT group.

스포츠 스타의 학교폭력 논란 보도에 대한 기호학적 분석

전상완(Jeon, Sang-Wan),이은석(Yi, Eun-Surk),박한솔(Park, Han-Sol) 한국스포츠사회학회 2023 한국스포츠사회학회지 Vol.36 No.2

본 연구는 스포츠계 학교폭력 논란의 언론 보도를 Saussure와 Barthes의 이론으로 기호학적 분석하여 언론 속이데올로기를 규명하고, 시사점을 제공하는 데 목적을 두었다. 전국종합일간지 언론에 명시된 언론사인 ‘세계일보’를 비롯해 ‘조선일보’, ‘경향신문’, ‘국민일보’, ‘내일신문’으로 선정하였고, 분석 대상 기간은 2021년 2월부터 2023년 2월 28일까지로 설정하였다. 통합체 분석을 통해 전개 과정을 시간적 흐름으로 분석함으로써 서사구조를 규명하고자 하였다. 다음으로, 계열체 분석을 통해 주체 간의 대립적 관계와 그 의미를 분석하고자 하였다. 끝으로, 분석된 결과물을 토대로 신화 분석을 통해 함축적 의미를 도출하였다. 연구 결과는 첫째, 서사구조는 발단 및 전개를 시작으로 절정, 결말의 단계로, ‘사건 논란’을 시작으로 ‘징계 및 처벌’, ‘은퇴 및 복귀’ 순으로 나타났다. 둘째, ‘가해자와 피해자 간의 대립구조’, ‘제3의 구단과 여론 간의 대립구조’, ‘가해 선수를 바라보는 옹호 입장과 반대 입장 간의 대립구조’로 나타났다. 셋째, ‘스포츠 속 피해자의 아나키즘’, ‘스포츠와 일반사회의 윤리적 상대주의’로 나타났다. 본 연구가 스포츠의 고질적인 문화와 풍토를 변화하는 데 촉매제가 되기를 바라며, 스포츠 폭력 문제의 패러다임을 구축하는 데 기여하고자 한다. The purpose of this study is to identify the ideology in the media and provide implications by semiotically analyzing media reports of school violence controversy in the sports world with the theory of Saussure and Barthes. We selected Segye Ilbo, a media company specified in the national daily newspaper press, Chosun Ilbo, Kyunghyang Shinmun, Kookmin Ilbo, and Naeil Shinmun, and the period of analysis was from February 2021 to February 2023 It was set up to 28 days. I tried to identify the narrative structure by analyzing the development process as a time flow through the integrated body analysis. Next, I tried to analyze the antagonistic relationship between subjects and its meaning through phylogenetic analysis. Finally, based on the analyzed results, the implications were derived through myth analysis. The results of the study are as follows: First, the narrative structure is in the order of initiation and development, climax, and ending, starting with incident controversy, followed by discipline and punishment, and retirement and return. Second, confrontational structure between the perpetrator and victim, confrontation structure between the third club and public opinion, and confrontation structure between the opposing position and the advocating position looking at the perpetrator were found. Third, anarchism of victims in sports and ethical relativism in sports and general society appeared. It is hoped that this study will serve as a catalyst for changing the endemic culture and climate of sports, and contribute to establishing a paradigm for the problem of violence in sports.

3D 모델링을 위하여 드론 라이다 및 광학 센서에서 생성된 포인트 클라우드의 품질 검증

이도훈(Lee, DoHoon),김창재(Kim, ChangJae),이한솔(Yi, HanSol),길성진(Kil, Seongjin),김혁찬(Kim, HyukChan) 대한토목학회 2023 대한토목학회 학술대회 Vol.2023 No.10

가시광 통신 기반의 실내 측위 및 안내 시스템 연구

경예지(Ye-Ji Kyeong),김민지(Min-Ji Kim),윤채원(Chae-Won Yun),이한솔(Han-Sol Yi),김철민(Cheol-Min Kim),정민우(Min-Woo Jung),고석주(Seok-Joo Koh) 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.12