• 에너지공학
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• 제24권4호
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• pp.105-116
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• 2015

본 연구에서는 절곡 깊이(1.4 mm)와 절곡 핏치(5.5 mm)가 같은 둥근 웨이브와 각진 웨이브 핀-관 열교환기에 대한 실험을 통하여 절곡 형상이 전열성능에 미치는 영향을 검토하였다. j 인자의 경우 둥근 웨이브 핀이 모든 열수에서 1.2~22% 크고 f 인자는 3열의 경우 8.3~23% 크고 1, 2열의 경우는 -1.0~29% 작다. 둥근 웨이브 핀이 우수한 성능을 보이는 이유로 둥근 웨이브 핀의 경우 각진 웨이브 핀 보다 유동이 핀의 곡면을 잘 따라갈 수 있으므로 골에 존재하는 재순환 영역의 크기가 줄어들기 때문으로 판단된다. 둥근 웨이브 핀의 경우 핀 핏치가 j와 f 인자에 미치는 영향은 크지 않다. 또한 j 인자는 튜브 열수가 증가할수록 감소하는 반면 f 인자는 튜브 열수와 무관하다. 실험 데이터로부터 새로운 상관식을 도출하였다.

• 설비공학논문집
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• 제21권6호
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• pp.347-354
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• 2009

Experimental study on a cross-flow air-cooled plate heat exchanger (PHE) was performed. Two types of PHEs were manufactured either with single-wave plates or with double-wave plates in parallel. Cooling air flows through the PHEs in a crosswise direction against internal hot water. The heat exchanger aims to substitute open-loop cooling towers with closed-loop water circulation, which guarantees cleanliness and compactness. In this study, prototype single-wave and double-wave PHEs were designed and tested in a laboratory scale experiments. From the tests, the double-wave PHE shows approximately 50% enhanced heat transfer performance compared to the single-wave PHE. However, the double-wave PHE costs 30% additional pressure drop. For the commercialization, a wide channel design for air flow would be essential for performance and reliability.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.37-38
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• 2005

Although the law of classical fourier heat conduction predicts the heat conduction phenomena occurred in most engineering fields with a good accuracy, it is also well-known that the conventional fourier law of a heat conduction has an application limit when the heating and cooling are periodic for a short duration or when the heat conduction is analyzed in the extremely low temperature region. This application limit of classical fourier law results from the fact that it assumed the infinite speed of a heat wave. In this study, we investigated the feasibility of whether the molecular dynamics could be used to calculate the speed of a heat wave through a solid. The calculated sound velocity showed a good agrement with the theoretical prediction qualitatively. From the calculated results, we confirmed that the same methodology can be applied the evaluation of the speed of a heat wave.

• 한국지리정보학회지
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• 제26권1호
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• pp.89-113
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• 2023

본 연구는 폭염 취약지역을 도출하고, 폭염 피해와의 공간적 일치성 분석을 통해 공간 유형화 및 정책적 방향성에 대해 논의하고자 한다. 연구 방법은 IPCC의 기후변화 취약성 평가와 공간통계 비교분석을 활용하였으며, 폭염이 가장 극심했던 2018년을 포함하는 5개년(2015~2019)의 전국 시군구를 대상으로 하였다. 폭염 취약성은 다양한 요소 중 폭염 영향을 나타내는 폭염일수(노출)가 가장 큰 영향을 미치고 있었으며, 폭염에 대한 민감도와 적응 능력은 지역의 특성에 따라 경향성이 나타나는 것으로 확인되었다. 폭염 취약성과 피해의 관계는 공간적 일치성을 통해 4개 유형으로 구분하였으며, 취약성과 피해가 정의 관계를 가지는 Hot to Hot, Cold to Cold 유형과 역의 관계를 가지는 Hot to Cold, Cold to Hot 유형을 도출하였다. 이는 유형별로 지역의 특성과 현황이 상이하므로 유형에 따라 개선을 위한 정책과 연구의 방향성을 달리 설정해야 한다는 시사점을 남긴다. 해당 연구는 폭염 취약성과 피해를 함께 고려하여 지역을 유형화하고, 유형별 대응 방향성에 대해 살펴본 점에서 추후 폭염 관련 정책 수립에 기초자료로 활용되기를 기대한다.

• 패션비즈니스
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• 제12권6호
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• pp.11-22
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• 2008

The goal of this study is to provide beauticians with the fundamental material to use effectively heat permanent wave in beauty industry as well as their customer's satisfaction. It carried out an experiment with damaged hair of a woman in her late twenties to investigate the change of physical and morphological characteristics by its water content when performing heat permanent wave. After spreading 0g, 1g, 2g, 3g, and 4g of water on damaged hair respectively, heat permanent wave was treated and the change of hair was observed. The change of physical characteristic was compared through permanent wave form of hair, tensile strength and elongation. The change of morphological characteristic was observed through Scanning Electron Microscope(SEM) and Transmission Electron Microscope(TEM). The result of experiment on the physical specificity revealed that permanent wave form was the most ideal when the water content was 2g, also 3g. Though the materials with much moisture content formed the results were not satisfied. The material with 0g of water content didn't make the wave. In terms of tensile strength and elongation, tensile strength was generally reduced as per the damaged degree of hair. On the contrary, elongation was increased. It observed the changes of morphological characteristic that the damage on hair cuticle was deepen, as its moisture content was decreased, and cuticle's surface was worn away. The observation of fine structure on hair section by transmission electronic microscope also certainly showed the result that damaged hair having experience with chemical treatment had got much damaged to hair cuticle as well as hair cortex. Generally chemical treatment makes hair damaged. Under consideration of this aspect, the ultimate goal of this thesis is to minimize the damage of hair caused by chemical treatment and get the satisfaction on the hair style. According to the result of experiment, the damaged hair whose moisture content was 3g showed the best permanent wave form.

• 한국의류산업학회지
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• 제10권3호
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• pp.389-393
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• 2008

The purpose of this study is to provide beauticians with the fundamental material for them to use effectively heat permanent wave and satisfy their customers. It carried out an experiment with hair of a woman in her late twenties to investigate the change of physical and morphologic characteristics by its water content when performing heat permanent wave. It evaluated the water content as 0g, 1g, 2g, 3g and 4g respectively when performing the heat permanent wave on hair, then it compared and observed the wave type, tensile strength and elongation for its physical change also observed the morphologic change by scanning electronic microscope and transmission electronic microscope. The result of experiment on the physical specificity revealed that the wave was the most ideal when the water content was 2 g. The material with much water content made wave but the result was not satisfied. In the case of hair with water content of nearly 0g didn't make wave. In terms of tensile strength and elongation, the tensile strength was generally reduced as hair was damaged, on the contrary, the elongation was increased. It observed the change of morphologic characteristic and got the result that the damage on hair cuticle was deepen as its water content was decreased. It also showed the result that damage happened on hair cuticle more than hair cortex with the observation of fine structure on hair section by transmission electronic microscope. Generally chemical treatment damaged hair. Under consideration of this aspect, the ultimate goal of this thesis is to minimize the damage of hair caused by chemical treatment and get the satisfaction on the hair style. The result of experiment presented that the hair showed the best result when its water content was 2 g.

• 대기
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• 제30권3호
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• pp.237-248
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• 2020

In order to effectively prepare for damage caused by weather events, it is important to proactively identify the possible impacts of weather phenomena on the domestic society and economy. Text mining and Network analysis are used in this paper to build a database of damage types and levels caused by heat wave. We collect news articles about heat wave from the SBS news website and determine the primary and secondary effects of that through network analysis. In addition to that, based on the frequency with which each impact keyword is mentioned, we estimate how much influence each factor has. As a result, the types of impacts caused by heat wave are efficiently derived. Among these types of impacts, we find that people in South Korea are mainly interested in algae and heat-related illness. Since this technique of analysis can be applied not only to news articles but also to social media contents, such as Twitter and Facebook, it is expected to be used as a useful tool for building weather impact databases.

• 한국수자원학회논문집
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• 제54권9호
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• pp.693-704
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• 2021

본 연구는 폭염과 하천수질과의 상관성을 평가하기 위한 것이다. 기상청 91개의 기상관측소의 일 최고기온 과 환경부 수질관측망 918개에 대한 13개의 하천수질인자(DO, BOD, COD, TOC, TN, DTN, NH4-N, NO2-N, NO3-N, TP, DTP, PO4-P, Chl-a)를 대상으로 분석하였다. 최고기온과 수질인자에 대한 상관성 분석을 수행하였으며, DO, Chl-a, T-N의 상관계수(R²)가 0.782, 0.609, 0.691로 가장 높은 상관성을 나타내었다. 폭염과 수질인자 간의 공간적 영향 분석을 위해, 일 최고기온을 이용하여 폭염강도(heat wave intensity, HWI)와 폭염지속시간(heat wave duration, HWD)를 산정하였다. 공간적 영향 평가는 핫스팟 분석과 공간통계분석을 실시하였다. 핫스팟 분석결과 폭염지수(HWD, HWI)는 낙동강 하류유역에 대해 높은 공간상관성을 나타내었으며 수질인자 중 Chl-a, TN이 동일한 결과를 나타내었다. 폭염에 따른 수질 영향 지역 공간 통계분석 결과 공간적인 변동성이 가장 뚜렷하게 나타나는 수질인자는 DO인 것으로 분석되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.155-161
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• 2000

In this paper, we studied the relation between heat-treatment temperature of ferrite and electromagnetic wave absorbing properties of ferrite-rubber composite. The heat-treatment temperatures of ferrite are 1200 and $1300^{\circ}C$, 2 hr. As s result. it has been shown that the optimum heat-treatment temperature of ferrite for electromagnetic wave absorber are related to the chemical composition. And, we can control electromagnetic wave absorbing properties of ferrite-rubber composite by the control of heat-treatment temperature of ferrite.

• 대한한의정보학회지
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• 제14권1호
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• pp.81-106
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• 2008

The ECG which used for this paper, is analysis result from alogrisms of arrythmia, and we have studied that how we could certain Cold(寒 )type or Heat(熱) type and that Deficiency(虛) type or Excess(實)type of organs from various special diseases, and we obtained like these results. 1. we depend on our examination about Pulse(脈) because we can't discriminate arrythmia using EKG analysis instruments. 2. We obtained that Cold(寒) type diseases had wave that prolonged above normal baseline and ST wave which had downward aptitude. 3. We obtained that Heat(熱) type diseases had the fibrillation which had shortend wave that compare to normal and had downward aptitude or negative aptitude. 4. We obtained that Respiratory system (肺) diseases had wave that is within normal or is short of normal range and had much fluctuation in potential difference or trans on P wave. 5. The character of EKG which presented about diseases of gastric systems is prolonged above narmal range of wave, and the EKG had represented mixed wave with Heat(熱) type when accompany inflammatory in gastric system. 6. The wave of Blood Stasis(瘀血) type had upward aptitude of QRS wave, and the wave of anemia or blood loss type(少血 ) had downward aptitude of QRS wave, the wave which had both Cold(寒) and Heat (熱) represented mixed waves. 7. The Knotted Pulse(結脈) and Intermittent Pulse(代脈) is corresponded with sinus brady cardia, and the Swift Pulsle(疾脈) is corresponded with fibrillation. 8. We pay attention to the relations of formations about pressures pulse from formations of EMD( electromechanical dissociation ). From these results, we will have to study about EKG which using in tests of change of Parkinsons disease.