• Journal of the Korean Magnetic Resonance Society
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• v.12 no.1
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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.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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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.

• Journal of the Korea Institute of Building Construction
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• v.17 no.5
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• pp.465-471
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• 2017

In this study, oxidized graphene nanoplatelet(GO) was prepared by oxidizing graphene nanoplatelet(GNP) with nitric acid in order to solve the problem of dispersion of GNP, one of nano materials. The surface chemical composition of the prepared GO was analyzed by fourier transform infrared spectroscopy(FT-IR) before incorporation into the epoxy paint, and the dispersibility in the solvent was confirmed. Meanwhile, GNP/Epoxy and GO/Epoxy paint were prepared by mixing GNP, GO with 0.1, 0.3, 0.5 and 1.0wt.% in epoxy paint and the mechanical properties were evaluated. As a result, GNP/Epoxy and GO/Epoxy paints showed better mechanical properties than Neat Epoxy which did not incorporate GNP, GO. Especially, when 0.3wt.% of GO was incorporated into epoxy resin, it showed higher tensile strength than Neat Epoxy. It was confirmed that acid treatment of GNP was effective in improving the mechanical properties of epoxy paint.

• Resources Recycling
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• v.8 no.3
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• pp.3-8
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• 1999

An air-washer was developed in order to remove the soil on the films collected from agricultural use, The washed films were subjected to TGA analysis to measure the residual soil content and DSC analysis to evaluate composition as well as compositional ratro, Mechanical properties of washed films were measured via tensile test ,md the properties of washed films were compared with those of neat resin blend. Major component of air washed films was polyethylene, and compositional ratio was 10:6:3:1 (HDPE:LLDPE:LDPE:EVA). 30 min air-washed films showed 2.1 % of residual soil content, while the water washed films had 1.5%. Tensile properties of washed (air and water) films were almost same as those of neat resin mixture.

• Transactions on Electrical and Electronic Materials
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• v.14 no.4
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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 $130^{\circ}C$.

• The Research Journal of the Costume Culture
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• v.1 no.2
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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.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.10a
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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.

• Journal of Adhesion and Interface
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• v.17 no.1
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• pp.7-14
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• 2016

Epoxy composites with concentrations of 5-70 wt% of silica particles were prepared in order to improve mechanical property and poor thermal stability. The mechanical and thermal properties were investigated and compared to the corresponding properties of neat epoxy composite. Furthermore, the effects of silane compound treatment on silica particles were observed by the experimental results of the tensile strength, glass transition temperature, and thermal stability of epoxy composite. Tensile strength of epoxy composites was measured by universal testing machine (UTM) and after that, the structure and morphology analysis of epoxy nanocomposites were analyzed by field emission scanning electron microscope (FE-SEM) and energy dispersive spectroscopy (EDS). The increased solid content of CA0030 particle improved the tensile strength of epoxy/ modified composites to give 30-50 MPa. The thermal expansion coefficients (CTE) of neat epoxy resin and epoxy/silica composites measured with a thermomechanical analyzer (TMA) showed that the incorporation of silica particles was helpful to reduce the CTE of neat epoxy resin.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.2
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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.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.1
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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.