• 전기화학회지
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• 제8권4호
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• pp.155-161
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• 2005

상용 CFD 프로그램인 FLUENT v5.3을 이용하여 용융탄산염 연료전지 스택의 수치 모사를 행하였다. FLUENT에 포함되어 있는 보존식들을 이용하면서, 사용자 정의함수를 이용하여 포함시킨 코드를 통해 전기화학적 반응과 부반응인 수성가스전이반응에 의한 질량과 가스 조성 변화 및 열이동을 고려하여 정확한 계산 결과를 얻고자 하였다. 모사에 사용된 스택은 6kW급과 25kW급 스택으로 각각 20개와 40개의 단위전지를 수직으로 적층한 형태이며 스택내로 주입되는 가스는 coflow형태로 각각의 채널을 흘러가게 설계되어 있다. 모사를 통해 알아본 스택 내 압력분포는 가스 흐름방향으로 압력강하가 일어나며 anode 채널보다 cathode 채널에서의 압력차가 더 크게 나타났다. 채널 내 속도분포는 전극 반응에 의한 질량 및 부피변화로 인해 anode 채널에서는 가스흐름 방향으로 속도가 증가하는 반면 cathode 채널에서는 속도가 감소하는 경향을 보였다. 스택 내 온도분포는 가스 흐름방향으로 증가하는 경향을 보였고, 계산결과와 실험결과가 대체로 일치함을 확인할 수 있었다. 수성가스전이반응을 포함한 모델과 그렇지 않은 모델을 비교한 결과 가스의 주입구 부분에서는 수성가스전이반응에 의해 흡열 반응이, 출구 부분에서는 발열반응이 일어나고, 이로 인해 입구와 출구의 온도차가 더 커짐을 확인하였다. 따라서 상용화 스택인 수백 kW급 이상의 대형 스택을 모사하기 위해서는 수성가스전이반응을 고려해야할 것으로 생각된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.143.2-143.2
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• 2016

The influence of electric field on CO adsorbed on Pt(111) was investigated with reflection-absorption infrared spectroscopy (RAIRS) in ultrahigh vacuum system. The ice film capacitor method was used to apply electric field to the amorphous ice film with CO on Pt(111). Two systems were compared by measuring the change of the CO stretching vibrational mode under applied electric field; one is CO on Pt(111), and the other is CO buried inside an ice film on Pt(111). By comparing them, we were able to calculate the additional effect of adsorption of CO on Pt(111) on peak shift. The CO adsorbed on Pt(111) has shown larger peak shift than CO adsorbed with H2O when we applied stronger electric field. Additionally, the differences were observable when the applied electric field exceeds $1{\times}10V/m^8$.

• 기본간호학회지
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• 제23권1호
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• pp.21-31
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• 2016

Purpose: This study is a qualitative research to identify new nurses' adaptation experience to sleep changes. Method: Grounded theory methodology was utilized. Participants were 10 new nurses from one university hospital. The information was collected and analyzed using the grounded theory of Corbin and Strauss'(2008). Results: Through constant comparative analysis, central phenomenon was identified as 'Shaky daily life due to the sleep change'. A core category emerged as 'In the shaky daily life, go grab my position', Causal conditions were 'Heaviness in shift work', 'Not released after getting off work', and 'Body and mind are exhausted'. Context were 'An environment that does not tolerate mistakes' and 'Clogged breathing due to worries'. Intervening factors were 'Support of colleagues', 'Recovery volition in restoration of altered relationships due to sleep'. Action/Interaction Strategies were 'To strive for a good sleep', 'Require a reasonable duty schedule' and 'Find a breakthrough'. Consequences were 'Become the master of shaky daily life' and 'Accepting the life of a nurse'. Conclusion: New nurses experience sleep patterns changes from the hospital shift system. but throughout the process of adaptation, came to accept sleep disorder as part of the life of a nurse.

• 한국전기전자재료학회논문지
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• 제21권11호
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• pp.1010-1018
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• 2008

In this report, we describe the use of gold nanoparticles (AuNPs) immobilized on pH. responsive, cross-linked poly(4-vinylpyridine) (P4VP) thin films, as a potential application for pH nanosensors. The methodology is based on the variation in surface plasmon resonance of immobilized AuNPs with changing the interparticle distances, caused by the swelling/deswelling of the pH responsive P4VP polymer films. The change in optical properties of the immobilized AuNPs in response to the pH of surrounding media was investigated by a simple yet powerful tool; UV-vis absorption spectroscopy. The swelling of the P4VP chains at pH 2 causes an increase in the interparticle distances of immobilized AUNPS ($\sim20nm$) and hence leads to a blue shift of 48 nm in their surface plasmon resonance band peak. On the other hand, when the surrounding media was altered from pH 2 to 10, a red shift of absorption maxima was observed. The changes were rapid, and the effect was reversible. This system could prove to be useful in fabricating nanosensors for detecting the pH or pH changes of surrounding aqueous medium.

• 센서학회지
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• 제14권3호
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• pp.186-190
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• 2005

This paper describes the development of a surface acoustic wave gas sensor that is designed to detect volatile gas by monitering phase change of output signal as a function of time. The sensor consists of SAW oscillators with a center frequency of 100 MHz fabricated on $128^{\circ}$ Y-Z $LiNbO_{3}$ substrates. Experimental results, which show the phase change of output signal under the absorption of volatile gas onto sensors, are presented. The proposed sensor has the properties of high sensitivity compare to the conventional SAW gas sensor and chemical selectivity. Thus, it is thought these results are applicable for use in sensor array of an high performance electronic nose system.

• 비교문화연구
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• 제39권
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• pp.355-380
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• 2015

China has been experiencing a series of changes after gradually opening up its society. Such changes have now seeped into almost every sector of the society, leading to overall change. While the political system has been maintained without much change, the structure of life for Chinese has undergone a shift, especially in the sectors related to industry or the economy. The Chinese have adopted capitalism in their own way, leading to fast growth in their industries. Those who were born in the 1980s amidst such change (so-called the post-80s generation) are now playing a major role in Chinese society. Understanding this generation can help understand some of the most important phenomena in today's China. Therefore the language used by this generation is in particular meaningful as language often reflects the society it is used in. This study focuses on the newly created words arising from the lifestyles of the post-80s generation to better understand how the China's move towards a more open society over the past three decades have brought about changes. The work culture and consumption styles of the post-80s generation are also showing some collective characteristics. As such, a review of newly created Chinese words related to this generation is expected to increase understanding of the overall Chinese society and Chinese culture of today.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.515-515
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• 2022

Climate change is strongly threatening the performance of agricultural reservoirs, which are instrumental in ensuring uninterrupted water supplies for rice cultivation in Korea. In this study, various performance indices were derived and overall sustainability of the 400 agricultural reservoirs was evaluated in the context of climate change trends during 1973-2017. Rice crop evapotranspiration, irrigation water requirements, runoff generation in the upstream watershed, and volumetric evaporation losses were plugged into a water balance model to simulate the reservoir operation during the study period. Resilience, reliability, and vulnerability are the three main indicators of reservoir performance, and these were combined into a single sustainability metric to define the overall system credibility. Historical climate data analysis confirmed that the country is facing a gradual warming shift, particularly in the central and southern agricultural regions. Although annual cumulative rainfall increased over the last 45 years, uneven monthly rainfall distribution during the dry and wet seasons also exacerbated the severity and frequency of droughts/floods. For approximately 85% of the selected reservoirs, the sustainability ranged between 0.35 to 0.77, and this range narrowed sharply with time, particularly for the reservoirs located in the western and southern coast regions. The study outcomes could help in developing the acceptable ranges of the performance indices and implementing appropriate policy and technical interventions for improving the sustainability of reservoirs with unacceptable ranges of the performance indices.

• 농촌지도와개발
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• 제19권4호
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• pp.1041-1066
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• 2012

농촌정책의 중요한 과제는 농촌 지역경제 활성화인데, 대다수 연구와 정책은 농업인과 농업을 중심으로 전개되고 있다. 그러나 지역경제 활성화는 지역 내의 다양한 산업이 얽혀 내외부의 변화에 반응하는 것으로 어느 한 부분의 성장만으로 농촌 지역경제 활성화는 달성되기 어렵다. 본 연구는 이러한 문제점을 바탕으로 충청남도 5개 군을 대상으로 농촌지역에서 농업부문의 위치를 살펴보고, 농촌에 위치한 산업별 변화요인을 살펴보았다. 분석결과 5개 군에서 농림어업은 수위산업으로서 역할을 담당하고 있으며, 지역 내부요인인 지역산업효과, 지역경쟁효과가 매우 취약함을 보여 5개 군에서 지역경제 활성화를 위해서는 위와 관련한 요인들의 성장을 위한 노력이 필요한 것으로 분석되었다. 또한 농림어업부분은 지역 외부효과에 의해 영향을 많이 받고 있었으며, 도소매업, 숙박 및 음식점업 등 농촌 지역에 기초수요를 제공하는 산업부문의 감소가 두드러지게 나타나고 있었다. 이러한 연구결과가 농촌지역에 주는 시사점은 다음과 같다. 우선 농림어업 내 생산물의 지역내 소비와 연결시키는 노력을 통해 지역산업과 연결시키는 개선이 필요할 것이며, 농촌지역 주민의 기초서비스를 제공하는 업종의 보호를 위한 정책적 수단마련을 위해 읍면소재지 개발 등의 사업내용에 소상공인 지원을 위한 사업내용의 고려가 필요하다.

• 산업경영시스템학회지
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• 제31권4호
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• pp.114-120
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• 2008

The control chart is widely used statistical process control(SPC) tool that searches for assignable cause of variation and detects any change of process. Generally, ${\bar{X}}-R$ control chart and ${\bar{X}}-S$ are most frequently used. When the production run is short and process parameter changes frequently, it is difficult to monitor the process using traditional control charts. In such a case, the coefficient of variation (CV) is very useful for monitoring the process variability. The CV control chart is an effective tool to control the mean and variability of process simultaneously. The CV control chart, however, is not sensitive at small shift in the magnitude of CV. In this paper, we propose an CV-EWMA (exponentially weighted moving average) control chart which is effective in detecting a small shift of CV. Since the CV-EWMA control chart scheme can be viewed as a weighted average of all past and current CV values, it is very sensitive to small change of mean and variability of the process. We suggest the values of design parameters and show the results of the performance study of CV-EWMA control chart by the use of average run length (ARL). When we compared the performance of CV-EWMA control chart with that of the CV control chart, we found that the CV-EWMA control chart gives longer in-control ARL and much shorter out-of-control ARL.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2007년도 한국지능정보시스템학회
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• pp.208-217
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• 2007

The media industry influenced by digital convergence is developing in the direction which the media consumers change their passive attitudes for positive participation on the base of the interactivity of convergence media of telecommunication and broadcasting. And content is progressing toward on-demand service which is customer-oriented and open. In light of these findings, interactivity is the most important feature which is able to shift the paradigm of the media industry and critical success factors which should be considered in order to plan the media strategy. This study is aimed at shedding light on the effects of interactivity factors, which are main factors of ubiquitous environment, on consumer's acceptance intention and describing the role of perceived interactivity and awareness of media substitution in the process of formation of acceptance intention..