• 한국분무공학회지
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• 제10권2호
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• pp.1-9
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• 2005

An experimental study was carried out to obtain the fundamental data about the effects of radical ignition on premixture combustion. A CVC(constant volume combustor) divided into the sub-chamber and the main chamber was used. Numerous narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in tile sub-chamber derives the simultaneous multi-point ignition in the main chamber. We have examined the effects of the sub-chamber volume, the diameter and number of passage holes, and the equivalence $ratio({\Phi})$ on the combustion characteristics by means of burning pressure measurement and flame visualization. In a CVC, the overall burning time including the ignition delay became very short and the maximum burning pressure was slightly increased by the radical ignition(RI) method in comparison with those by the conventional spark ignition(SI) method. Combustible lean limit by RI method is extended by ${\Phi}=0.25$ compared with that by SI method. Also, In cases of charging the number and the diameter for the fixed total cross section of the passage holes, combustion period increased significantly at a sub-chamber with a single hole, but those of the other conditions had almost a similar tendency in the sub-chamber with 4 or more holes. regardless of equivalence ratio. Therefore, it was Proved that a critical cross section exists with the number of passage holes.

• 복식문화연구
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• 제19권4호
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• pp.723-739
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• 2011

This research seeks to analyze western men's costume in the Baroque era in relation to men's physical beauty from its most detailed and interesting perspective to fomulate a plausible reasoning related to the aesthetic sense of body as expressed in men's costume. This research used national and international books, theses and internet data upon which to base a literature review for a correct understanding of Baroque style and at the same time empirical research to analyze the body image expressed in men's costume. The Baroque style expressed in the 17th century costume offered a dynamic feeling through wavy curves, and its brilliant and colorful decorations created a passionate and charming mood resembling a flame. Accordingly, this research studied the body image as it appeared in the form of 17th century western men's costume by dividing it into the contact beauty of the human body and the manner of hiding the architectural beauty of the human body. First, the exposed silhouette by clothing coming into contact with the human body could be found mainly in upper-class men's costume in the first half of the 17th century. The shorter and tighter doublets and knee breeches could be analyzed in terms of erotic imagery that emphasized masculinity, aristocratic imagery that stressed a distinctive status, and geometric imagery that expressed a triangular pattern. Second, the constructive expression by hiding the human body could be found in upper-class men's costume starting in the mid-17 century. The wearing of the justaucorps could be studied in terms of how it came into contact with the beauty of the human body but also how this clothing style the hid the architectural beauty of human body.

• 한국대기환경학회지
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• 제27권4호
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• pp.454-459
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• 2011

In this study, the recovery rate of Tedlar bag (T) sampler was investigated in comparison to polyester aluminum bag (P) sampler. To derive the comparative data sets for the relative performance between different samplers, a series of calibration experiments were performed by using 1 ppb standard of four offensive reduced sulfur compounds (RSC) odorants ($H_2S$, $CH_3SH$, DMS, and DMDS) along with $SO_2$ and $CS_2$. All the analysis was made by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server/thermal desorber (AS/TD). The measurement data were obtained by loading gaseous standards (1 ppb) at 3 injection volumes (250, 500 and 1,000 mL) at three intervals (0, 24 and 72 hrs). The recovery rates (RR) of P sampler were computed against the slope values of T sampler. According to our analysis, P sampler exhibits slightly enhanced loss relative to T, especially with light RSCs ($H_2S$ and $CH_3SH$). At day 0, RR for the two were 88 and 85%, respectively. Such reduction proceeded rather rapidly in the case of $H_2S$ through time. However, P sampler was more stable to store $SO_2$ unlike others. Despite slightly reduced recovery, P sampler appears as a good replacement of T sampler.

• 한국토양환경학회지
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• 제3권1호
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• pp.3-9
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• 1998

본 연구는 휘발성 유기 화합물로 오염된 가솔린 지역에서 soil-gas의 분석결과로부터 오염도를 유추하는 기법에 대하여 서술 하였다. Soil-gas의 채취방법으로는 펌프를 이용한 1)grab sampling법과 흡착제 trap을 사용한 2)passive sampling법이 있다. Grab sampling법은 특정시간에 특정장소에서의 오염도를 보여주며, 반면에 passive sampling법은 특정위치에서 시간에 따른 오염도의 변화를 보여 준다. Soil-gas의 분석은 1)PID나 FID와 같은 작은 검지기에 의해서 총괄 탄화수소량을 측정할수도 있고 2)기체농도에 따라서 색깔이 변하는 지시약이 채워진 기체검지기 튜브를 사용할수도 있으며 3)여러가지 화합물을 한 번에 분석할수 있는 이동형 GC를 사용할수도 있다. Soil-gas를 이용한 측정법은 매우 값싸며 세밀한 정밀조사를 하기 위한 전단계에서 사용할 수 있는 유용한 방법으로 추천할만하다 하겠다.

• 한국정밀공학회지
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• 제33권5호
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• pp.393-400
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• 2016

High frequency induction heating (HFIH) is used in many industries and has a number of advantages, including reliability and repeatability. It is a non-contact method of providing energy-efficient heat in the minimum amount of time without using a flame. Recently, HFIH has been actively studied using the finite element method (FEM), however, these studies only focused on the accuracy of the analysis. In this paper, we can measure joule heat distributions by the electromagnetic analysis for HFIH and the temperature distribution from the heat transfer analysis by applying joule heat for a sprocket. The sprocket is heated over $850^{\circ}C$ due to joule heat and then cooled to under $200^{\circ}C$ by using cooling $20^{\circ}C$ water. These processes were used to calculate the FEM and then compared to our experimental results. The calculated outcome may be used to predict hardening depth in HFIH.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.137-142
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• 2008

액체로켓엔진 재생냉각 연소기에서 산화제 선공급 cyclogram시의 점화 특성에 대해 기술하였다. 연소기의 연소압력은 60 bar, 추진제 유량은 약 89 kg/s 그리고 노즐 팽창비는 12이다. 산화제 선공급 cyclogram을 위해 수행한 연소기로의 연료 및 산화제 수류시험, 산화제 선공급에 따른 점화기 작동성 확인을 위한 점화시험, 연소기의 주 점화 및 연소 확인을 위한 저압 연소시험 그리고 설계점에서 연소기 작동성/연소 안정성 및 연소성능/재생냉각 성능 확인을 위한 연소시험 등에 대해 기술하였다. 산화제 선공급 점화 및 연소시험은 성공적으로 이루어졌으며 연소기에 대한 안정적인 점화 cyclogram을 개발하였다.

• 한국전자통신학회논문지
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• 제13권6호
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• pp.1229-1234
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• 2018

본 논문에서는 풍력발전기 너셀 내부에서 발생 가능한 화재를 예방하거나 신속하게 대응하기 위하여 광대역 전력선통신시스템 기반 화재 예방시스템을 구현하고 실증실험을 수행한 결과를 제시한다. 이를 위하여 고속 전력선통신용 주파수 대역에서 우수한 손실 특성을 가지는 유도성 통신 연결장치도 제작하였다. 구현된 시스템은 터빈 너셀에 설치된 온도, 불꽃, 연기센서 등 다양한 센서 정보와 열화상 이미지를 전력선통신시스템을 통하여 지상관제소에 고속 전송함으로써 너셀 내부의 환경변화를 실시간으로 감시할 수 있음을 확인하였다. 따라서 구현된 시스템은 이미 설치된 기존 안전시스템과 연동하여 풍력발전기 화재감시 및 예방체계의 신뢰성을 크게 향상시킬 수 있을 것으로 기대된다.

• 공업화학
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• 제22권4호
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• pp.439-443
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• 2011

수산화마그네슘이 첨가된 저밀도 폴리에틸렌-에틸렌 비닐 아세테이트 혼합물의 연소성을 시험하였다. 저밀도 폴리에틸렌-에틸렌 비닐 아세테이트에 수산화마그네슘을 40~80 wt% 첨가하여 용융 혼합하고 성형 후 콘칼로리미터(ISO 5660-1)를 이용하여 그의 연소성을 시험하였다. 수산화마그네슘을 첨가한 시험편은 첨가하지 않은 시험편에 비하여 그의 연소성이 감소하였다. 이것은 순수한 저밀도 폴리에틸렌-에틸렌 비닐 아세테이트에 첨가한 수산화마그네슘의 흡열 분해 때문에 연소 억제성이 향상된 것으로 생각된다. 수산화마그네슘을 첨가한 시험편은 첨가하지 않은 시험편에 비해 낮은 최대열방출률과 낮은 유효연소열을 나타내었고, 수산화마그네슘 함량이 증가할수록 착화시간은 길어지고, 최대열방출률은 감소하였다.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.84-96
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• 2022

In the worst case, a temporary ignition source (also known as transient combustibles) between two electrical panels can damage both panels. Mitigation strategies for electrical panel fires were previously developed using fire modeling and risk analysis. However, since they do not comply with deterministic fire protection requirements, it is necessary to analyze the boundary values at which combustibles may damage targets depending on various factors. In the present study, a sensitivity analysis of input variables related to the damage threshold of two electrical panels was performed for dimensionless geometry using a Fire Dynamics Simulator (FDS). A new methodology using a damage evaluation map was developed to assess the damage of the electrical panel. The input variables were the distance between the electrical panels, the vertical height of the fuel, the size of the fire, the wind speed and the wind direction. The heat flux was determined to increase as the vertical distance between the fuel and the panel decreased, and the largest heat flux was predicted when the vertical separation distance divided by one half flame length was 0.3-0.5. As the distance between the panels increases, the heat flux decreases according to the power law, and damage can be avoided when the distance between the fuel and the panel is twice the length of the panel. When the wind direction is east and south, to avoid damage to the electrical panel the distance must be increased by 1.5 times compared to no wind. The present scale model can be applied to any configuration where combustibles are located between two electrical panels, and can provide useful guidance for the design of redundant electrical panels.

• 대한화상학회지
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• 제23권2호
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• pp.42-53
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• 2020

Purpose: It is important to consider both clinical factors and epidemiological factors in treating burn patients in emergency rooms. However, many emergency medical staffs happen to miss their chances of treating burns based on these considerations. This study is designed to find a better treatment for burn patients in emergency rooms along this approach. Methods: This study was conducted based on the data of the burn patients visiting the emergency room of a single general hospital from January 2015 to December 2019. The epidemiological and clinical factors were extracted out of the data, then the relationship between the prognosis and these factors were analyzed. Results: Most of burn accidents occurred at home, and were caused by hot water, soup, drinks, oil, etc. Especially, flame burns showed high hospitalization rate, surgical rate and mortality. In addition, their prognosis was poor when the affected area included facial, limb and perineal areas etc., or any inhalation burn co-existed. Also, the hospitalization rate and period increased when the treatment time was delayed or the pre-treatment was taken. There was a strong relationship between prognosis and the period of follow-up when patients were admitted during the period. Conclusion: It is difficult for medical staffs to evaluate prognosis of burns in emergency rooms due to progressive damages. Precise treatment and disposition are essential for patients' good prognosis. Therefore, medical staffs should establish treatment plans by identifying the patient's epidemiological and clinical factors, rather than giving prescriptions based on fragmentary and superficial symptoms.