• 한국대기환경학회지
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• 제25권6호
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• pp.481-492
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• 2009

The characteristic of cold water by upwelling in the southeast of the Korean Peninsula and the effect of sea breeze in this region are investigated. The coastal upwelling around the southeast coast of the Korea Peninsula is analyzed by using Coastal Oceanographic Data statistical analyses for 5 years were carried out. The period of an cold water event, on the average, was observed southwesterly wind events. The analysis suggests that strong and persistent southwesterly winds in period of an cold water play an important role of bring the moisture to the surface, generating persistent cyclone as jangma. In order to investigate the effect of cold water on sea breeze, we considered two case. First, Exp. 1 is not occurred coastal upwelling on sea breeze. Second, Exp. 2 is occurred cold water on sea breeze. Two experiments were completed separately to the effects of cold water by upwelling. The results show the sea breeze is stronger in Exp. 2, when the cold water occurs, and weaker in Exp. 1, when there is no cold water. In order to verify the effect of the sea breeze on the cold water by upwelling, on the intensification and change of direction of the prevailing wind, the sea breeze effectively intensify cold water condition.

• 한국해양학회지:바다
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• 제28권1호
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• pp.19-40
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• 2023

여름철 제주해협 물성 분포의 특성과 제주해협 수괴가 연안에 미치는 영향을 확인하기 위하여 2019년 6월, 7월, 8월에 완도와 제주도 사이에서 수온과 염분을 관측하였다. 여름철 계절 수온약층 아래에서 15℃의 저온수가 관측되었으며, 이 저온수는 관측시기에 따라 다르지만 수심이 깊은 제주해협 남쪽 골보다는 주로 제주해협 중앙의 중층과 북쪽 사면에 분포하였다. 이 저온수를 구성하는 근원 수괴를 알아보기 위하여 제주해협에서 관측된 해수를 구성하는 주변 근원 수괴들의 혼합비(mixing ratio)를 계산하였다. 여름철 제주해협 중앙 중층과 북쪽 사면에 나타나는 저온수는 평균적으로 쿠로시오 아표층수가 54% 그리고 황해저층냉수가 33% 비율로 혼합된 해수였다. 이 중층 저온수는 제주해협 전 수층에서 가장 낮은 수온을 갖는 해수임에도 상대적으로 고온고염인 쿠로시오아표층수가 큰 구성비율을 갖고 있다. 중층 저온수가 제주해협에서 가장 낮은 수온의 분포를 갖게 된 이유는 다른 제주해협 해수에 비해 황해저층냉수의 기여도가 높기 때문이다. 제주해협 중층 저온수의 기원을 살펴보기 위하여 황해, 동중국해, 대한해협에서 2019년 여름철에 관측한 광역 수온과 염분 자료를 분석하였다. 제주도 남서쪽 동중국해 계절 수온약층 아래에서 쿠로시오 기원의 해수와 황해저층냉수가 열염전선을 형성하였고, 이 열염전선을 가로지르는 수괴의 관입에 의해 해수의 혼합이 발생하였다. 동중국해에서 형성된 이 혼합수는 제주해협에서 관측된 중층 저온수와 거의 같은 혼합비율을 가졌다. 이런 결과들을 종합하였을 때 제주해협에서 여름철에 관측된 중층 저온수는 동중국해에서 쿠로시오 아표층수와 황해저층냉수의 혼합으로 만들어진 저온수가 해류를 따라 이동한 것이다. 제주해협 중앙과 북쪽 사면으로 이동한 중층 저온수는 제주해협 중앙의 중층에서 수온역전을 만들고, 한국 남해안 연안의 표층 수온 변동에도 큰 영향을 미친다.

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1296-1302
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• 2002

A mathematical model for cold rolling and temper rolling process of thin steel strip has been developed using the influence function method. By solving the equations describing roll gap phenomena in a unique procedure and considering more influence factors, the model offers significant improvements in accuracy, robustness and generality of the solution for the thin strip cold and temper rolling conditions. The relationship between the shape of the roll profile and the roll force is also discussed. Calculation results show that any change increasing the roll force may result in or enlarge the central flat region in the deformation zone. Applied to the temper rolling process, the model can well predict not only the rolling load but also the large forward slip. Therefore, the measured forward slip, together with the measured roll force, was used to calibrate the model. The model was installed in tile setup computer of a temper rolling mill to make parallel setup calculations. The calculation results show good agreement with the measured data and the validity and precision of the model are proven.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2001년도 춘계 학술발표논문집
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• pp.157-158
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• 2001

In 2001, extremely cold air covered Korean peninsula during mid-January, recording - 29.2$^{\circ}C$ in Cheolwon region in Kangwon province. As a result, 4 cities or department below -$25^{\circ}C$ and 10 cities or department between 20 to -24.9$^{\circ}C$ were under the anxiety of cold injury in peach and grape. This survey and investigation was carried out to elucidate the characteristic symptoms of cold injury in peach and to obtain the basic information about the phenomenon, which could be occur in low air temperature.(omitted)

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.238-239
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• 2006

Nozzle geometry influences gas dynamics making sprayed particle behavior one of the most important parameters in cold spray process. Gas flows at the entrance convergent section of the nozzle takes place at relatively high temperature and are subsonic. Thus, this region is a very suitable environment for heating spray particle. In this study, numerical simulation and experiments were conducted to investigate the effect of nozzle contour, entrance geometry of nozzle and powder injection position at nozzle on the cold spray process. The process changes were observed through numerical simulation studies and the results were used to find a correlation with coating properties.

• 한국어병학회지
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• 제13권2호
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• pp.147-151
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• 2000

저온 처리에 의한 버들치, Rhynchocypris oxycephalus에서의 척주 기형을 발견하였다. 외형적으로 기형의 기형 위치는 미병 부위이었다. 이런 기형에 대한 x-ray 사진 조사 및 조직학적 조사 결과 기형을 확인할 수 있었으며 특히, 조직학적 조사시 기형은 미네랄화된 조직의 내적작용에 기인되어 척주 관절의 광범위한 융합을 나타내었다. 본 연구 결과, 저온 처리가 버들치에서 내적으로 척주 융합을 일으킨다는 직접적인 증거를 보여주었다.

• 소성∙가공
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• 제28권4호
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• pp.190-196
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• 2019

The capability of accurately predicting the roll force profile across a strip in the bite zone in cold rolling process is vital for the calculation of strip profile. This paper presents a derivation of a precision mathematical model for predicting variations in the roll force across a strip in cold rolling. While the derivation is based on an approximate 3-D theory of rolling, this mathematical model also considers plastic deformation in the pre-deformation region which is located close to the roll entrance before the strip enters the bite zone. Finally, the mathematical model is expressed as a boundary value problem, and it predicts the roll force profile and tension profile in addition to lateral plastic strain profile.

• 한국초지조사료학회지
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• 제27권4호
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• pp.257-262
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• 2007

본 시험의 목적은 대구 경북에 자생하는 헤어리베치로 다수성 조생품종과 중만생품종을 개발하기 위하여 수행하였다. 경북 성주와 경남 사천에서 1998년부터 2006년까지 자료수집 및 순화, 생육이 왕성한 조생 및 중만생계통 선발, 상호교잡의 단순순환선발법으로 조생종인 콜드그린과 중만생종인 청파를 육성하였다. 육성종자는 2004년부터 2006년까지 경북성주와 경남사천에서 생육특성과 수량을 평가하였다. 줄기의 털은 콜드그린과 청파는 있었으나, 헤이메이커프러스와 라티고는 없었다. 잎의 모양은 콜드그린은 엽폭이 넓은 장타원형이고, 청파, 헤이메이커프러스, 라티고는 좁은 장타원형이었다. 꽃색은 콜드그린은 자주색이고 청파는 보라색이었다. 내한성은 성주에서 콜드그린, 청파, 라티고가 헤이메이커프러스 보다 높았으며 사천에서는 차이가 적었다. 개화기는 콜드그린과 헤이메이커프러스가 조생종으로 유사했고 중만생종인 청파는 라티고 보다 다소 빨랐다. 성주에서 건물수량은 콜드그린이 다른 품종 보다 높았으며 청파와 헤이메이커프러스는 라티고 보다 높았다(P<0.05). 2005년 사천에서는 콜드그린과 헤이메이커프러스는 다른 품종보다 높았으며, 청파는 라티고 보다 높았다(P<0.05). 베치의 조단백질 함량은 높고 ADF의 함량은 낮았다.

• Ocean and Polar Research
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• 제42권2호
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• pp.97-113
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• 2020

In-situ observations were carried out in April 2015 to investigate the occurrence of water temperature inversion in a region west of Jeju Island. Analysis of in-situ in the western part of Jeju island showed that cold water moved to the southeast from the surface to the middle layer and warm water moved from the middle to the lower layer of the northwest direction. The water temperature inversion occurred at 84 stations (63.1%) out of 133 stations. At the boundary of the water temperature inversion layer, it was formed in the middle layer and disappeared. In the strongly appearing, it started from the middle layer to the lower layer. The shape of the water temperature inversion layer was different. As a result of horizontal water temperature slope analysis of the water temperature inversion zone, maximum 0.23℃/km was obtained and the mean was 0.06℃/km. The role of water temperature inversion as an indicator to determine the formation of water front. As a result of the water mass analysis, Jeju Warm Current Water and Tsushima Warm Current Water of high temperature and high salt intruded from the middle to the bottom. In the middle layer occurred as the Yellow Sea Cold Water of low water temperature and low salinity expanded.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.796-801
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• 2001

During cold operation period, fuel injection system directly contributes the unburned hydrocarbon formation in spark ignition engines. The relationship between injection parameters and HC emission behavior was investigated through a series of experiments. Spray behavior of port fuel injectors was characterized through a quantitative evaluation of mass concentration of liquid fuel by a patternator and PDA. 6-hole injector was found to produce finer spray than single hole one. Using a purpose-built test rig, the wall wetting fuel was measured, which was mostly affected by wall temperature. Varying coolant temperature($20{\sim}80^{\circ}C$), HC emissions were measured in a production engine. With respect to the different types of injectors, HC emission was also measured. In the 6-hole injector application, the engine produced less HC emission in low coolant temperature region. Though it produces much more amount of wetting fuel, it has the advantages of finer atomization quality. In high coolant temperature region, there was little effect between different types of injectors. The control schemes to reduce HC emissions during cold start could be suggested from the findings that the amount of fuel supply and HC emission could be reduced by utilizing fine spray and high intake wall temperature.