• 대기
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• 제29권4호
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• pp.429-438
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• 2019

Organic carbon (OC) and elemental carbon (EC) in PM_2.5 were measured with Sunset Laboratory Model-5 Semi-Continuous OC/EC Field Analyzer by NIOSH/TOT method at Anmyeondo Global Atmosphere Watch (GAW) Regional Station (37°32'N, 127°19'E) in July and August, 2017. The mean values of OC and EC were 3.7 ㎍ m^-3 and 0.7 ㎍ m^-3, respectively. During the study period, the concentrations of reactive gases and aerosol compositions were evidently lower than those of other seasons. It is mostly due to meteorological setting of the northeast Asia, where the influence of continental outflow is at its minimum during this season under southwesterly wind. While the diurnal variation of OC and EC were not clear, the concentrations of O₃, CO, NOx, EC, and OC were evidently enhanced under easterly wind at night from 20:00 to 8:00. However, the high concentration of EC was observed concurrently with CO and NOx under northerly wind during 20:00~24:00. It indicates the influence of thermal power plant and industrial facilities, which was recognized as a major emission source during KORUS-AQ campaign. The diurnal variations of pollutants clearly showed the influence of land-sea breeze, in which OC showed good correlation between EC and O₃ in seabreeze. It is estimated to be the recirculation of pollutants in land-sea breeze cycle. This study suggests that in general, Anmyeondo station serves well as a background monitoring station. However, the variation in meteorological condition is so dynamic that it is primary factor to determine the concentrations of secondary species as well as primary pollutants at Anmyeondo station.

• 방재기술
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• 통권15호
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• pp.22-27
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• 1993

The classification of hazardous area is a method of analysing and classifying the environment where explosive gas or vapour atmosphere may be expected to be present. The object of area classification is to enable the proper selection and installation of electical apparatus and other equipments. This report is intended to serve a general reference about the classification procedure of hazardous area with explanations of related Korean Standard.

• 대한지역사회영양학회지
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• 제5권2호
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• pp.225-235
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• 2000

Service quality has become an important factor to meet customer satisfaction in the food service industry where competition is getting severe. Organizations are focused upon strengthening customer loyalty through customer satisfaction. Therefore, this study, taking customers as subjects, is intended to analyze factors affecting customer loyalty, on the basis of service quality satisfaction. In doing. so, the analysis has been done with 232 customers who are purchasing service from the food services industry, for general information, and service quality expectation, service quality satisfaction and overall satisfaction. The results of the study are as below. 1) From a factor analysis, the service quality expectation level of customer has been categorized into 4 factors, which are named General ′General management ′, ′Food′, ′Reliability′and ′Reputation′. 2) From the factor analysis, the service quality satisfaction level of customer has been categorized into 6 factors, which are named ′Employee attitude′, ′Food′, ′Reliability′, ′Atmosphere′, ′Reputation′ and ′Price′. 3) After classifying customers into 3 groups according to two criteria-"will buy the service again" and "will suggest to others", a comparison has been done for the service quality expectation dimension of customers by each customer group. The result shows that the group having both the "will buy the service again" and "will buy the service again "and "will suggest to others" criteria, that is, with higher customer loyalty, tend to have higher point than other group in factors of ′Food′, ′Reliability′, ′Reputation′(p〈.05). 4) As per the dimension of customer\`s service quality satisfaction level, factors like ′Employee attitude′, ′Food′, ′Reliability′, ′Atmosphere′, ′Reputation′, and ′Price′have shown differences according to each loyalty group(P〈.001). 5) Customers′overall satisfaction level according to each customer loyalty group has been found to be more important for the group having a higher loyalty level(p〈.001) 6) From the discriminant analysis with employing judging variables, such as the customer′s service quality expectation level, service quality satisfaction level and general satisfaction level, customer loyalty groups have been identified as accurately as 68.9% of the explanatory power.

• 동아시아식생활학회지
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• 제20권5호
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• pp.812-822
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• 2010

This study explored choice attributes in specially coffee shops and examined the relations between choice attributes and positive emotions customers felt in specially coffee shops. The study also attempted to find differences in choice attributes and positive emotions according to general characteristics of customers and coffee-drinking behavior. Measured items were derived from preliminary interviews and a literature review. Questionnaires were distributed to customers in Seoul who had visited a specially coffee shop in the last 3 months. The derived factors of choice attributes were 'taste of coffee and atmosphere', 'brand', 'price benefit', 'pleasant space', and 'coffee itself. Among those, the two factors 'taste of coffee and atmosphere', and 'brand' had a statistically significant influence on positive emotions of customers. This implies that specially coffee shop customers have primarily emotional rather than utilitarian motivations. Therefore, to better satisfy customers' desires, more effort is needed to improve the physical environment in coffee shops. Female and younger customers showed higher perception of price benefits than others did. The perception of price benefits and pleasant space mainly varied by the location of coffee-drinking and frequency of visiting specially coffee shops. Further differences in positive emotion according to general characteristics and behaviors of having coffee also discussed.

• 한국가스학회지
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• 제1권1호
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• pp.1-6
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• 1997

가연성 가스가 존재하는 위험 분위기에서 전기기기를 사용할 경우 전기 스파크에 의한 폭발위험성이 존재하기 때문에 점화원을 격리시키거나 고립시키는 것이 필요하지만 현실적으로 점화원의 고립이 불가능하므로 폭발을 방지하기 위한 일반적인 방법으로 내압 방폭형전기기기를 사용하고 있다. 따라서 내압방폭기기의 내부에 침투한 가연성 가스가 폭발하여도 화염이나 열이 틈새를 통과하여 외부의 가연성 분위기를 점화시킬 수 없는 최대 틈새크기를 찾아야 할 필요가 있다. 본 논문에서는 수소-공기 혼합기와 메탄-공기 혼합기에 대하여 실험적 최대틈새크기(MESG)를 찾아내어 기존의 결과와 비교하고, MESG에 영향을 미치는 요인들을 찾아내고자 하였다. 실험장치는 내용적 8${\iota}$의 구형용기를 사용하였으며 실험 변수들로는 전화위치, 혼합기의 농도, 초기압력 등이었다. 실험결과 각각의 변수들에 의해 영향을 받으며 특히 농도와 초기압력에 크게 영향을 받는 것을 알 수 있었으며, 당량 농도 가까이에서 최소값을 나타내었으며 초기압력의 상승과 함께 MESG는 감소하였다.

• 한국항공우주학회지
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• 제50권10호
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• pp.739-745
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• 2022

전투기의 여러 가지 환경 요구도 중 폭발성 대기는 항공기 체계와 승무원의 안전을 위해 군수품의 점화 여부를 확인하는 시험이다. 시험은 한국생산기술연구원(KITECH)에서 보유하고 있는 폭발성 대기 시험장비를 활용하였고, 보수적으로 시험을 수행하기 위해 일반 연료보다 점화 특성이 민감한 n-hexane을 사용하였다. 미 군용 환경시험 규격서인 MIL-STD-810G w/Change 1, Method 511.6, Procedure I을 바탕으로 적용 범위와 테일러링(Tailoring) 가이드, 세부 시험절차를 확인하고 전투기의 각 계통에 대한 본 시험의 필요성을 고찰한다. 본 연구를 통해 전투기에 장착되는 구성품에 대한 폭발성 대기 시험 결과를 분석하고, 도출한 주안점을 공유하여 올바른 테일러링 방안을 제시한다.

• 항공우주기술
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• 제2권1호
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• pp.190-196
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• 2003

2002년 7월부터 2003년 11월까지 항우연에서 직수신한 MODIS 자료를 이용하여 한반도 여러 지역의 top-of-atmosphere(TOA) radiance 및 그 계절변동을 분석하였다. MODIS의 공간분해능과 한반도 특성에 맞게 광범위하게 분포하는 동일한 특성을 갖는 지역을 선택하여 농경지역, 수림지역, 담수지역, 해수지역, 도시지역, 습지, 대기영역(구름)을 선택하였다. 한반도의 선택된 지역에 대해 TOA radiance값이 지표특성에 의존적임을 알 수 있었다. 또한 MOIDS 관측이 일반적으로 알려져 있는 지구복사특성을 잘 묘사하고 있음을 이해하게 되었다. 본 저자들은 이 연구가 초다중분광(hyperspectral) 자료해석에 기초정보를 제공하기를 기대한다.

• 천문학회보
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• 제35권1호
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• pp.26.1-26.1
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• 2010

In this talk we outline the current understanding of solar flares, mainly focusing on magnetohydrodynamic (MHD) processes. A flare causes plasma heating, mass ejection, and particle acceleration which generates high-energy particles. The key physical processes producing a flare are: the emergence of magnetic field from the solar interior to the solar atmosphere (flux emergence), formation of current-concentrated areas (current sheets) in the corona, and magnetic reconnection proceeding in a current sheet to cause shock heating, mass ejection, and particle acceleration. A flare starts with the dissipation of electric currents in the corona, followed by various dynamic processes that affect lower atmosphere such as the chromosphere and photosphere. In order to understand the physical mechanism for producing a flare, theoretical modeling has been develops, where numerical simulation is a strong tool in that it can reproduce the time-dependent, nonlinear evolution of a flare. In this talk we review various models of a flare proposed so far, explaining key features of individual models. We introduce the general properties of flares by referring observational results, then discuss the processes of energy build-up, release, and transport, all of which are responsible for a flare. We will come to a concluding viewpoint that flares are the manifestation of the recovering and ejecting processes of a global magnetic flux tube in the solar atmosphere, which has been disrupted via interaction with convective plasma while rising through the convection zone.

• 대한지역사회영양학회지
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• 제15권5호
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• pp.687-693
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• 2010

This study investigated difference of general eating habit and eating-out behavior between men and women of university students in Gyonggi area. The survey was conducted from 1 March to 1 April 2010, in Gyeonggi area. Self-administered questionnaires were collected from 250 students in Gyeonggi area. The research results show, first of all, that they eat twice a day, and they usually do not eat breakfast. The main reason why they do not eat breakfast is that they do not have enough time to eat. Between men and women, there is significant difference in eating amount and eating speed at 0.001 levels. Men's problems of eating behavior are irregular meal time and speed of eating time, and in case of women, they do not have a meal regularly and overeat at one time. Second, they usually eat out for a meal and gather with friends once to three times a week. Also, the lunch set-menu promotion is the most preferred one. Third, when men choose a restaurant, they consider in order of taste, convenience, amount, and service; women consider in order of atmosphere, taste, convenience, and service. Taste is the most important for men; atmosphere is the most important consideration for women. Taste (at 0.01 levels), sanitation (at 0.05 levels), and atmosphere (at 0.001 levels) are significantly different between men and women in choosing restaurant.

• 한국환경보건학회지
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• 제11권2호
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• pp.1-16
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• 1985

There are a large number or chemical compounds that are present in a polluted atmosphere and that alone or in combination are important to consider for their potential effect on the respiratory system and impact on athletic performance. A general categorization or description of the level of pollution in terms of the concentration of one or more compounds or by type such as oxidizing compounds is inadequate and misleading. A useful initial categorization of pollutant compounds according to their mechanism of production, primary or secondary, is often made. For health effects, consideraiions of the physical state, gaseous or particulate, and the solublity and reactivity of the pollutant is also important. Pollutant compounds or substances that are emitted directly from a source and that undergo little or no chemical change in the atmosphere from source to receptor are termed primary pollutants.