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기후변화에 따른 한반도 사스레피나무의 생육지 예측과 영향 평가
윤종학,박정수,최종윤,나카오 카츠히로,Yun, Jong-Hak,Park, Jeong Soo,Choi, Jong-Yun,Nakao, Katsuhiro 한국환경영향평가학회 2017 환경영향평가 Vol.26 No.5
본 연구는 사스레피나무의 분포를 규정하는 기후요인과 종분포 모델을 이용하여 현재기후와 미래기후에서의 잠재생육지를 분석하기 위해 수행되었다. 4개 기후요인(온량지수, 최한월최저기온, 하계강수량, 동계강수량)은 모델에서 독립변수로 사용하였다. 17개 전지구 기후모델(GCMs; General Circulation Models)에 의한 RCP(대표농도경로) 8.5 시나리오를 2050년(2040~2069)과 2080년(2070~2099)의 미래기후로 사용하였다. 사스레피나무(Eurya japonica)에 대한 종분포 모델은 높은 분포예측 모델로 구축되었다. 사스레피나무의 분포모델에서 최한월최저기온이 사스레피나무 분포를 규정하는 주요 기후요인으로 분석되었다. 최한월최저기온 $-5.7^{\circ}C$이상 지역은 사스레피나무의 높은 출현확률을 나타내었다. 사스레피나무의 잠재 생육지는 2050년과 2080년에서 현재기후에서 보다 각각 2.5배, 3.4배 증가되었으며, 기후변화에 의해 점점 확대될 것으로 판단되었다. 사스레피나무는 한반도에서 기후변화 지표종으로 가능하며, 잠재 생육지를 모니터링 할 필요가 있다. The research was carried out in order to find climate factors which determine the distribution of Eurya japonica, and the potential habitats (PHs) under the current climate and climate change scenario by using species distribution models (SDMs). Four climate factors; the warmth index (WI), the minimum temperature of the coldest month (TMC), summer precipitation (PRS), and winter precipitaion (PRW) : were used as independent variables for the model. Seventeen general circulation models under RCP (Representative concentration pathway) 8.5 scenarios were used as future climate scenarios for the 2050s (2040~2069) and 2080s (2070~2099). Highly accurate SDMs were obtained for E. japonica. The model of distribution for E. japonica constructed by SDMs showed that minimum temperature of the coldest month (TMC) is a major climate factor in determining the distribution of E. japonica. The area above the $-5.7^{\circ}C$ of TMC revealed high occurrence probability of the E. japonica. Future PHs for E. japonica were projected to increase respectively by 2.5 times, 3.4 times of current PHs under 2050s and 2080s. It is expected that the potential of E. japonica habitats is expanded gradually. E. japonica is applicable as indicator species for monitoring in the Korean Peninsula. E. japonica is necessary to be monitored of potential habitats.
머시닝센터에서 볼 엔드밀가공으로 고능률, 고정밀도 제고를 위한 표면가공 조건
윤종학,이종원,정기영,정문섭 한국공작기계학회 1998 한국생산제조학회지 Vol.7 No.3
The curved surface machined by plate end mill causes a excess non-cutting volume, in these cases ball end mill is used for the curved surfaces. This study is aimed to obtain the optimum cutting condition by measuring the surface roughness on the conditions of various cutting speed, table speed, tool diameter, radius of curvature when machining the curved surface using the ball end mill. After designing curve rates, obtaining NC data by CAD/CAM system through CC-Cartesian method and transferred the data through DNC system, we machined the specimens by the CNC machining center. The surface roughness of specimens was measured by surface roughness tester and CNC 3D coordinate measuring machine. The cutting condition were the same as follow, velocity ; 15, 20, 25, 30m/min, feed rate ; 40, 60, 80, 100m/min amd redius of curvature ; 30, 40, 50, 60mm, tool diameters ; Φ8, Φ12, Φ16, Φ20mm. Analizing the working results, we can acquire the acquire the optimum cutting condition of curved specimen at the cutting velocity of 20∼25m/min and the feed rate of 80mm/min. As the same cutting condition, the best surface roughness was showed at Φ16mm of the tool diameter. But the tool diameter was smaller than Φ8mm, we could improve for the surface roughness by controlling the cusp.
국가직무능력표준(NCS) 기반 인쇄분야 국가기술자격 설계 방안
윤종학,김재해,소기호,박계영 한국인쇄학회 2017 한국인쇄학회지 Vol.32 No.1
This study is briefed the national competency standards(NCS) which developed through occupational map analysis in printing fields and the national technical qualifications which were Engineer Printing, Industrial Engineer Printing and Craftsman Printing. And the question for skill test of printing fields was developed by comparing NCS and guideline for question-making. Finally the new system of technical qualification based on printing NCS was designed.
윤종학,이호영,이종원 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.2
This study was focused on the prediction of the appropriate tool life by clarifying the correlation between progressive drill wear and AE signal, on drilling SM45C. the following results have been obtained : RMS_AE , AE CUM-HITS and CUM-CNTS had a tendency to increase slowly according to wear size, at 1000rpm, 150mm/min. However, these increased suddenly in the range of 0.20~0.22mm wear, about 102 holes and had a tendency to go up and down until the drilling was impossible. The sudden increase of AE signal shows that something is wrong and it is closely connected with drill wear and chipping. It also makes the working surface bad. From the above results, AE signal could be sued to monitor the drill's condition and to determine the right time to change tools.
윤종학,여만구,김상헌 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.3
This study is focused on the prediction of appropriate tool life by clarifying the correlation between progressive tool wear and AE(Acoustic Emission) signals, while cutting stainless steel by end mill on te machining center. The results of this study were that RMSAE tends to increase linearly along with the incrase of the cutting speed, and it was more sensitive to depth of cut than to the variation of feed rate at the same cutting conditions, and RMSAE increases around 0.21mm flank wear hereby AE-HIT also increases. AE signals depend upon tool wear and fracture from the above results. Therefore, the AE signals can be utilized in order to monitor the tool condition.
Al합금의 고속 원통가공에서 발생하는 치수오차와 진원도의 영향 고찰
윤종학,서성원,이헌철 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.5
Recently, the requirements for high precision and efficiency machining are gradually increased to raise international competitiveness at the industrial fields of die and molds. This trend had made effects on the industrial fields in Korea and which needs for studying of high precision and efficiency machining. This study is to investigate the effects of the run-out of end mill in the external cylindrical machining operated by solid carbide end mills with Al-alloy in high speed machining center relating to high spindle revolution and fast feed per minute on the dimensional precision, roundness of workpiece. From the results of experimentation followings are obtained; when Al-alloy is processed by the external cylindrical cutting of end milling through the high speed revolution, if the spindle revolution is higher relating to radial depth of cut, feed per tooth in very lower situation, finally, productivity can be raised because high precision and quality products are machined high efficiently.
工具壽命을 判定하기 위한 Acoustic Emission(AE) 검출방법의 활용성 연구
윤종학 서울産業大學校 1987 논문집 Vol.26 No.1
Acoustic Emission (AE) is ued to detect the cutting tool failure in the automated machining system, and to detect the micro-scopic processes of the material deformation and failure during the up-set forging. AS the result, we got the following conclusions; 1. It was observed that amplitude level of AE signal was affected by cutting velocity only, and amplitude level of AE signal was directly proportional to flank wear width and the increasing rate was velated to cutting velocity. So, the relation between amplitude level of AE signal and tool life was represented as follow, ?? where, n=0.35, ?? 2.?? is not much affected by feed rate, but drop 10-15% of it's value by lubricating. 3. Also in the plastic deformation on the same forming ratio, the plastic tensile instability point was reached more rapidly on the lubricated condition than non-lubricated and was appeared rapid increase of AE generation by crack and breakage.