• 한국자기공명학회논문지
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• 제12권1호
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• pp.60-64
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• 2008

Cross-polarization (CP) signals were observed even from liquid samples such as neat toluene. Therefore, CP signals of liquid molecules in the presence of high surface materials do not necessarily mean the molecules are adsorbed on solid surface, especially when no signal from the tertiary observing nuclei such as carbons of the molecules is detected.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.222-222
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• 2012

Metal oxide gas sensors based on semiconductor type have attracted a great deal of attention due to their low cost, flexible production and simple usability. However, most works have been focused on n-type oxides, while the characteristics of p-type oxide gas sensors have been barely studied. An investigation on p-type oxides is very important in that the use of them makes possible the novel sensors such as p-n diode and tandem devices. Monoclinic cupric oxide (CuO) is p-type semiconductor with narrow band gap (~1.2 eV). This is composed of abundant, nontoxic elements on earth, and thus low-cost, environment-friendly devices can be realized. However, gas sensing properties of neat CuO were rarely explored and the mechanism still remains unclear. In this work, the neat CuO layers with highly ordered mesoporous structures were prepared by a template-free, one-pot solution-based method using novel ink solutions, formulated with copper formate tetrahydrate, hexylamine and ethyl cellulose. The shear viscosity of the formulated solutions was 5.79 Pa s at a shear rate of 1 s-1. The solutions were coated on SiO2/Si substrates by spin-coating (ink) and calcined for 1 h at the temperature of $200{\sim}600^{\circ}C$ in air. The surface and cross-sectional morphologies of the formed CuO layers were observed by a focused ion beam scanning electron microscopy (FIB-SEM) and porosity was determined by image analysis using simple computer-programming. XRD analysis showed phase evolutions of the layers, depending on the calcination temperature, and thermal decompositions of the neat precursor and the formulated ink were investigated by TGA and DSC. As a result, the formation of the porous structures was attributed to the vaporization of ethyl cellulose contained in the solutions. Mesoporous CuO, formed with the ink solution, consisted of grains and pores with nano-meter size. All of them were strongly dependent on calcination temperature. Sensing properties toward H2 and C2H5OH gases were examined as a function of operating temperature. High and fast responses toward H2 and C2H5OH gases were discussed in terms of crystallinity, nonstoichiometry and morphological factors such as porosity, grain size and surface-to-volume ratio. To our knowledge, the responses toward H2 and C2H5OH gases of these CuO gas sensors are comparable to previously reported values.

• 한국건축시공학회지
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• 제17권5호
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• pp.465-471
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• 2017

본 연구에서는 그래핀 나노플레이트릿(Graphene nanoplatelet ; GNP)의 분산에 대한 문제를 해결하고자 질산으로 이를 산화시켜 GO를 제조하였다. 이렇게 제조한 GO를 에폭시 도료에 혼입하기 전, 푸리에변환적외선분광법(Fourier transform infrared spectroscopy; FT-IR)을 이용한 화학조성 분석과 용매에서의 분산안정성을 확인하였다. 그 후, GNP, GO를 에폭시 도료에 0.1, 0.3, 0.5, 1.0wt.% 혼입하여 GNP/Epoxy, GO/Epoxy 도료를 제조하고 역학적 특성을 평가하였다. 실험 결과, FT-IR 분석을 통해 GO에서 하이드록시기, 에폭시기, 카르복시기 기능기가 생성된 것을 확인할 수 있었다. 또한, GO는 GNP보다 증류수와 에탄올에서 분산안정성이 향상되는 것을 확인하였다. 한편, GO/Epoxy 도료는 Neat Epoxy, GNP/Epoxy에 비해 역학적 특성이 향상되었으며, 특히 0.3wt.% 혼입률에서 높은 역학적 특성을 나타내었다. 따라서 GO를 에폭시 수지에 강화제로써 혼입할 경우 에폭시 도료의 역학적 특성을 향상시키는데 효과적인 것으로 판단된다.

• 자원리싸이클링
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• 제8권3호
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• pp.3-8
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• 1999

농업용 폐비닐 재활용을 위하여 공기를 이용한 세척기를 개발하였으며, 이를 이용하여 농업용 폐비닐을 세척하였다. 세척된 폐비닐에 남아있는 잔류 흙의 양을 TGA로 그리고 구성 성분은 DSC로 분석하였다. 재활용 비닐의 물성은 인장 시험으로 측정하였으며, 구맹된 수지와 비교하였다. 재활용 비닐의 주요 구성성분은 PE로 HDPE, LLDPE, LDPE, EVA가 10:6:3:1비로 나타났다. 공기세척지로 30분 세척된 폐비닐은 2.1%의 잔류량을 보였으며, 한국자원재생공사에서 물로 세척된 폐닐은 1.5%의 잔류량을 보였다. 세척된 비닐의 물성은 구매된 수지를 같은 비율로 혼합한 시료와 비슷한 값을 보였다.

• Transactions on Electrical and Electronic Materials
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• 제14권4호
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• pp.221-224
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• 2013

Effects of ambient temperature on the ac electrical treeing and breakdown behaviors in an epoxy/layered silicate (1 wt%) were carried out in needle-plate electrode geometry. A layered silicate was exfoliated in an epoxy base resin,, using our ac electric field apparatus. To measure the treeing initiation and propagation, and the breakdown rate, constant alternating current (ac) of 10 kV (60 Hz) was applied to the specimen in a needle-plate electrode arrangement, at $30^{\circ}C$, $90^{\circ}C$ or $130^{\circ}C$ of insulating oil bath. At $30^{\circ}C$, the treeing initiation time and the breakdown time in the epoxy/layered silicate (1 wt%) system were 1.4 times higher than those of the neat epoxy resin. At $90^{\circ}C$ (lower than Tg), electrical treeing was initiated in 55 min, and propagated until 1,390 min at the speed of $0.35{\times}10^{-3}mm/min$, which was 4.4 times higher than that at $30^{\circ}C$; however, there was almost no further treeing propagation after 1,390 min. At $130^{\circ}C$ (higher than Tg), electrical treeing was initiated in 44 min, and propagated until 2,000 min at the speed of $0.96{\times}10^{-3}mm/min$. Typical branch type electrical treeing was obtained from the neat epoxy and epoxy/layered silicate at $30^{\circ}C$, while bush type treeing was observed out from the needle tip at $90^{\circ}C$ and $130^{\circ}C$.

• 복식문화연구
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• 제1권2호
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• pp.199-219
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• 1993

This paper analyzes how a social status is symbolized by clothing in Charles Dickens' novel 「The Tale of Two Cities」. The result shows that clothing symbols of he upper class people are splendid, perfect, good material, beautiful, younger looking, and fashionable. Meanwhile, those on the middle class people are neat, unpretentious, simple, practical, following fashion, and graceful. Finally, those on the lower class people are unfitted, disordered, careless, worn and shabby, unclean, disharmonious, coarse, and uniform.

• 한국막학회:학술대회논문집
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• 한국막학회 1995년도 추계 총회 및 학술발표회
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• pp.22-28
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• 1995

Since the discovery of liquid crystallinity by Reinitzer [1] in 1988 as he studied the melting behavior of cholesteryl benzoate, anisotropic structural ordering in fluid phases has been of considerable interest to chemists, physicists and other scientists. Polymers which exhibit liquid crystallinity either in solution (lyotropic) or in the neat state upon heating (thermotropic) have both theoretical and practical importance [2]. Du Pont's Kevlar, a high modulus polyamide fiber spun from a lyotropic solution, is a prime example of such an application.

• 접착 및 계면
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• 제17권1호
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• pp.7-14
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• 2016

에폭시 수지는 취성(brittleness)으로 인한 기계적 강도의 저하가 발생하고 금속 등과 같이 열팽창 계수가 다른 재료와 결합하여 함께 사용하는 경우에 열변형 차이 때문에 부품의 박리나 부분 손상 등이 일어나는 단점이 있다. 본 연구에서는 복합재료의 기계적 강도 및 열안정성을 높이기 위하여 아민기를 가진 실란 커플링제를 이용하여 표면 처리한 실리카 입자를 에폭시 수지에 첨가하여 강화된 복합재료 시편을 제조한 에폭시 복합재료 시편을 대상으로 분산의 적절성을 확인하고 기계적 특성과 열적 물성을 평가하고자 하였다. 함량 변화에 따른 기계적 특성 변화를 UTM으로 인장강도를 측정한 결과 30-50 MPa의 인장강도 값을 보였다. 실리카 입자가 에폭시 수지 내에 함량에 따라 분산된 정도를 비교하기 위해 SEM 및 EDS 분석을 수행하였다. TMA 분석을 통하여 열팽창계수 및 유리전이온도를 확인하였으며 열충격 실험을 통하여 에폭시 복합소재의 내열안정성을 평가하였다.

• 간호행정학회지
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• 제5권2호
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• pp.369-388
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• 1999

This study is a descriptive research to establish a positioning strategy of nursing service image, making a perception map on each hospital's nursing service image and ranking construct factors of nursing service image. The results in this study were as follows; 1. The rank of construct factors of nursing service image which were thought important by subjects was the first 'Kindness', the second 'Reliability', the third 'Professional Knowledge', the fourth 'Responsibility', and the fifth 'Advanced Nursing Skill'. 2. The perception map for nursing service image on each hospital showed a hierarchial structure and positioned the first B hospital, the second C hospital, the third D hospital, the fourth A hospital, and the fifth E hospital. The perception map for construct factors of nursing service image and hospitals showed the first dimension : 'Reliability', the second dimension : Kindness', the third dimension : 'Mission', 'Accuracy', 'Neat Appearance', and 'Ethical Aspect', and the fourth dimension : 'Client Advocate', 'Humanistic Consideration', 'Professional Knowledge', 'Responsibility', and 'Advanced Nursing Skill'. 3. The findings of subject's characteristics which affected degree of likeness on each hospital nursing service image to make a marketing strategy were as follows : In A hospital D hospital, and E hospital, the subject group whose hospital dates were under 1 week, education level was upper graduate university, and age was between 40's and 50's, were appeared to have low nursing service image on following construct factors : 'Kindness', 'Reliability', 'Responsibility', 'Mission', 'Neat Appearance', and 'Humanistic Consideration'. In B hospital and C hospital the subject group whose hospital dates were under 1 week or over 5 weeks, sex was woman, and age was 20' s or 40's, having a admission experience on subject hospitals, were appeared to have low nursing service image on following construct factors : 'Professional Knowledge', 'Advanced Nursing Skill', 'Ethical Aspect', and 'Humanistic Consideration'. As the based on above results, nursing managers can use positioning method to develope a marketing strategy for nursing service image.

• 한국의류학회지
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• 제33권1호
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• pp.1-10
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• 2009

The purpose of this study was to investigate the effects of the types and the colors of men's casual wear, hairstyles, and the methods of stimulus manufacture on men's image perception. The subjects were 360 women from the metropolitan area of Seoul. The clothing types used for the study were a sweater and a jumper(casual jacket) with jean pants. The clothing colors were beige, indigo, and red. Two hairstyles, the short and the medium length hairs, were compared. Two types of stimuli, the photograph and the computer simulation picture, were used. The results of the factor analysis disclosed five dimensions on men's image: neatness, individuality, ability, activity, and sociability. In general, the photograph stimuli were evaluated more positively in activity, individuality, and sociability than the picture stimuli. The sweaters were perceived higher in ability, activity, and sociability than the jumpers. The Indigo color was evaluated as neat. The medium length hairstyles were perceived as neat and the short hairstyles were perceived as sociable. The jumpers were evaluated lower in individuality in the picture stimuli than in the photograph stimuli. The beige and indigo colors were evaluated to be neater in the picture stimuli than in the photograph. When using the picture stimuli, the men's image wearing the sweaters with the medium length hairstyles were evaluated lower in individuality. When using the photograph stimuli, the men's image wearing the sweater with the short hairstyles were evaluated higher in activity. Men's image wearing the indigo jumper and the beige sweater with medium length hairs were evaluated as high in neatness.