정밀 광학 부품의 복굴절 측정 방법에 관한 연구

민인기,고영배,권창오,윤경환,Min, In Ki,Ko, Young Bae,Kwon, Chang Oh,Yoon, Kyung Hwan 한국금형공학회 2012 한국금형공학회지 Vol.6 No.1

Recently, injection molding process became more popular than ever to produce large quantities of high precision products. Extensive studies have been conducted for reducing the residual stresses and birefringence in injection-molded optical products. Flow-induced and thermally-induced stresses and birefringence have been found as two main sources during injection molding process. Generally, quantitative value of birefringence can be measured with polarizing microscope using the compensator. However, it is difficult to measure low order retardation with microscope, so developing a measurement system for low order optical path difference is in need. In the present paper, a system using Photo Elastic Modulator (PEM) is demonstrated to measure low phase retardation in injection-molded products.

해상관측부이의 현장 안정성 및 성능 예측을 위한 수치해석 : 정적해석

전인식(Insik Chun),민용침(Yongchim Min),민인기(In-Ki Min) 한국연안방재학회 2020 한국연안방재학회지 Vol.7 No.4

It is very important to predict the in-situ stability and performance of ocean surface buoys prior to the their installations in order to prevent their damages and to achieve high quality observation data. In the present study, a numerical method was set up to predict the static behaviors of the single point moored observation buoys subject to stationary loads by wind and/or currents. The numerical analysis was applied to the condition of an existing hydraulic experiment, and it appeared that both numerical and experimental results agreed well within an appropriate range of the drag coefficient of buoy. In addition, through the numerical analysis, the possibility of total submersion of buoy at very high current velocities was demonstrated together with a suggestion of its counter-action.

파랑관측부이의 성능예측을 위한 수치해석:동적해석(규칙파)

전인식(Insik Chun),민인기(In-Ki Min),민용침(Yongchim Min),오병철(Byungcheol Oh),심재설(Jaeseol Shim) 한국연안방재학회 2021 한국연안방재학회지 Vol.8 No.3

The prediction of the performance of a wave observation buoy is very important to acquire both in-situ security and good observation quality. In the present study, a numerical method was set up to analyze the dynamic interaction of a spherical buoy with its single point mooring line subject to regular wave conditions. The method was applied to the condition of an existing hydraulic experiment, producing results that are well compatible with experimental results within the limited accuracy of the available data. It was argued that some discrepancies between the numerical and experimental results might be due to the uncertainties of the wave exciting forces acting on the buoy and the experimental conditions of mooring line. The method was finally applied to demonstrate two practical issues related to in-situ wave height measurements; the effect of buoy size on resulting heave motion and the aspect of the numerical integration of heave acceleration to get wave profile.

합성형 사장교의 3차원 공기역학적 특성에 대한 실험적 연구

민인기,채영석,Min, In Ki,Chae, Young Suk 한국강구조학회 2008 韓國鋼構造學會 論文集 Vol.20 No.6

The aim of this study was to analyze the aerodynamic properties of the composite cable-stayed bridge by conducting three-dimensional wind tunnel tests. Focusing on the improved section of the bridge in the two-dimensional wind tunnel tests, the bridge's aerodynamic stability was estimated based on the angles of attack and the wind angles. The aerodynamic properties of vertical galloping, torsion galloping,and torsion flutter were also estimated based on the design wind velocity, and because much of the cable-stayed bridge was constructed using FCM, it was not sufficiently stiff during the bridge's construction. Therefore,the experience progressed by stages: from the full stage to the tow stage, and until the bridge became a single tower. Since the original plane was designed to be a steel box girder, the aerodynamic properties of the steel-box-type and composite-type girder could be compared. The results of this study can be utilized as basic data regarding the aerodynamic properties of medium-length and short composite cable-stayed bridges. 본 연구의 목적은 3차원 풍동실험을 이용하여 합성형 사장교의 공기역학적 특성을 분석하는데 있다. 2차원 풍동실험에서 선정된 내풍개선 단면을 가지고 영각, 풍각에 대하여 3차원 모형의 내풍안정성을 평가한다. 설계풍속에서 수직, 비틀림 와류진동, 비틀림 플로터 등의 공기 역학적 특성을 규명하였다. 또한 사장교는 FCM으로 대부분 가설하므로 가설단계에서 강성이 부족하다. 따라서 실험은 완성계, 2개의 가설단계, 독립주탑의 단계별로 나누어 진행되었다. 원설계가 강상형교로 설계되었기 때문에 강상형교와 합성형교의 내풍특성을 비교하였다. 이 논문은 중소형 합성형 사장교의 내풍특성의 기초 자료로 활용될 수 있을 것이다

직무분석을 통한 전문대학 건설 교육과정 개발과 적용

민인기(Min, In Ki),조성호(Cho, Sung Ho),민관식(Min, Kwan Sik) 한국지적정보학회 2013 한국지적정보학회지 Vol.15 No.1

최근 건설 사업들의 대형화와 복잡화 추세에 따라 건설 전문 인력에게 요구되는 역량과 역할이 점점 더 다양해지고 있기 때문에, 전문대학을 졸업하고 건설 산업에 종사하게 될 미래의 전문 인력들에게 다양한 분야의 역할이 요구되어지고 있다. 그러나 현행 교육과정으로는 건설 산업체에서 요구하는 교육과정을 충족시키지 못하고 있는 실정이다. 본 연구에서는 직무분석법을 이용하여 건설 분야 산학협력 맞춤교육을 위한 교육과정 개발하고 이를 적용함으로써 건설 분야의 우수한 전문 직업인을 양성하고자 하였다. 직문분석법은 위원회 구성원들의 자유로운 생각을 공유하고 다른 사람들의 의견을 취함으로써 보다 객관성을 확보하고 교육을 목적으로 교육목표와 교육내용을 비교적 단시간 내에 추출하여 교육과정을 개발하는데 효과적인 방법인 데이컴 기법을 활용하였으며. 본 교육과정을 이수한 학생은 사용자측에 요구에 부합된 전문 직업인으로 고용되는 결과를 얻을 수 있었다. Recent businesses in the field of construction tend to be large-scale as well as complicated so that various special skills are required to people who are supposed to work in the construction industry after they graduate from a college. With the outdated curriculum in the college, however, they have not been qualified for this requirements. In this study, using job analysis method Construction Sector Cooperation for customized training and curriculum development were trained by the superior professionalism in the field of construction. DACUM Method used of job analysis objectivity allows you to share the free thinking of the members of the Committee, and to collect the opinions of others. In addition, the educational goals and educational content within a relatively short period of time to develop and extract is the most effective way. The students who took an educational process developed in this study have been hired as qualified professionals according to demand of industry.

장기 계측 데이터를 이용한 가거초 해양과학기지의 동특성 평가

김원술(Wonsul Kim),이진학(Jin-Hak Yi),민인기(In Ki Min),심재설(Jae Seol Shim) 한국연안방재학회 2017 한국연안방재학회지 Vol.4 No.5

In order to study ocean and meteorological changes related to the global climate change and global warming, Korea is operating several ocean research stations (ORS) including Ieodo ORS, Gageocho ORS and Sochengcho ORS in remote ocean area. In 2011, the Gageocho ORS was attacked by Typhoon Muifa and was damaged to its structural members and various observation equipments. After that, the Gageocho ORS was reconstructed with increased height by 5m and then dynamic response measurement system has been built to assess the structural integrity of Gageocho ORS whether it is healthy or not. Using the measured dynamic response data including acceleration and tilt, the structural dynamic characteristics of the Gageocho ORS were investigated. As a result, three natural frequencies of the first two bending modes and the first torsional mode were estimated as 1.79 Hz, 1.82 Hz and 2.65 Hz, respectively, and the difference between natural frequencies for two bending modes is not significant because is almost symmetrical shape. It is also found that, when the acceleration response is larger, the damping ratios in first mode can be obtained more consistently with lower irregular fluctuations. The averaged damping ratio was about 0.7%. The present results and those obtained from long term monitoring can be used to identify and to assess the structural integrity of the Gageocho ORS, and can be useful in preliminary design of offshore structures.

성형 안정성을 고려한 바이오 칩 금형 설계 및 제작

민인기(In Ki Min),유재원(Jae Won Yu),김종선(Jong Sun Kim),고영배(Young Bae Ko),황철진(Chul Jin Hwang),김종덕(Jong Deok Kim),김경민(Kyung Min Kim),김병일(Byung Il Kim),이성호(Sung Ho Lee),윤경환(Kyung Hwan Yoon) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

Recently, many types of micro-chip have been developed with the help of lab-on-a-chip technology. One of the chips is a bio-chip, which should be made at low price and needs mass production for commercial use. Currently, micro-pattern of a bio-chip is fabricated in many ways (PDMS casting, etching, hot embossing, injection molding, etc). Among those the injection molding is the most adequate method for mass production. In the present study, the mold for injection molding was designed and fabricated for specific bio-chip. Two types of runner(curved type, straight type) were applied for flow stability. Also, a sliding mechanism was applied for a new ejection process in moving part of the mold. As a result, no ejector pins were required in demolding. Also, CAE results were used for the optimal processing condition.

폴리머수지와 폴리이소부틸렌을 복합한 자착식시트의 방수성능평가를 위한 역학적 실험연구

민인기 ( In Ki Min ),태기호 ( Ghi Ho Tae ) 한국안전학회(구 한국산업안전학회) 2012 한국안전학회지 Vol.27 No.5

The purpose of this study is to investigate waterproofing performance of self adhesive sheet combined polymer resin and poly-iso butylene. For the performance estimation of external waterproofing of concrete underground structures, there can be required various properties such as adhesion strength, hair crack resistance, repeat low and high temperature test, and so on. In this study, there engineering properties of composite system using polymer resin and poly-iso butylene were examined and could be confirmed to satisfy the guidelines of KS. Especially, it was turn out that the adhesion properties was excellent and high crack-resistance up to 1.49mm will be perform.

소청초 종합해양과학기지 원격제어·관측시스템 구현

민인기(Min, In Ki),정진용(Jeong Jin Yong),정종민(Jeong, Jong Min),민용침(Min, Yong Chim),심재설(Shim, Jae Seol) 한국연안방재학회 2015 한국연안방재학회 학술발표대회 논문집 Vol.2015 No.-

세 번째 해양과학기지인 소청초 종합해양과학기지가 건설되어 시범 운영중에 있다. 소청초 기지에는 기상, 해양, 환경 등의 관측장비, 등대, 디젤발전기와 복합 발전기, 침입자 감시장비 등이 설치되어 운영되고 있다. 이들 장비 및 설비는 원격 관측 및 제어가 가능하도록 설계와 시스템 구축이 이루어져 있으며 이를 통해 얻어지는 데이터는 위성통신망을 통해 육상 운영사무실과 송·수신이 가능하도록 시스템이 구현되어 있다. 육상에는 전송된 데이터가 안정적으로 저장, 활용될 수 있도록 서버가 설치되어 운영되고 있으며, 실시간 기반으로 기지의 모든 설비 및 장비상태를 감시하고 필요 시 원격제어할 수 있도록 기능이 갖추어져 있다.

석재(石材) 가공(加工)시 발생한 석분(石粉)이 혼합된 콘크리트의 압축강도(壓縮强度) 특성(特性)에 관한 연구

채영석,민인기,송갑용,Chae, Young-Suk,Min, In-Ki,Song, Gab-Young 한국자원리싸이클링학회 2009 資源 리싸이클링 Vol.18 No.6

석재 가공 시 발생되는 석분은 산업폐기물로 되어있다. 현재 이 석분은 지하에 매립하거나 지상에 야적되어 방치되고 있어 폐기물로 처리하는 데 많은 비용이 요구되고 있고, 토질과 지하수 등의 환경오염의 원인이 되고 있다. 또한 콘크리트의 주재료인 골재의 공급이 부족한 현실을 고려하여 본 연구에서는 폐석분을 콘크리트 혼화재료로 재활용할 수 있는 가능성을 연구하고자 한다. 석분함유량에 대한 시멘트비를 조정한 결과, $20{\sim}30\;N/mm^2$의 콘크리트의 압축강도가 나타났고 이는 석분의 함유에 따라 압축강도가 감소되지 않음을 알 수 있었다. 석재 가공 시 발생되는 석분을 콘크리트 혼화재료로 재순환하여 사용하여도 콘크리트의 압축강도에는 전혀 문제가 없음을 알 수 있었다. The stone dusts produced during the manufacturing process of stone blocks are considered as one of industrial waste materials. This stone dusts are managed to either burying under the ground or stacking in the yard, but this disposal process is required an extra costs. The stone dust disposal like burying or stacking also cause environmental pollution such as ground pollution and subterranean water pollution. Thus, this study was conducted to explore the possibility of recycling stone dusts as a concrete mixing material in order to extend recycling methods. Based on the experiment results on various ratios of cement to stone dust content, the compressive strengths of concrete were recorded in the range of $20{\sim}30\;N/mm^2$. The results did not show any decrease in compressive strength due to the stone dust content. It can be concluded that the stone dusts produced by stone block manufacturing can be sufficiently recycled as one of concrete mixing materials in the aspect of compressive strength.