• Food Science and Preservation
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• v.31 no.1
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• pp.126-137
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• 2024

In this study, zinc oxide nanoparticles (ZnONPs) were synthesized using three distinct zinc salts: zinc acetate, zinc chloride, and zinc nitrate. These ZnONPs were subsequently utilized in the fabrication of carrageenan-ZnONPs (Car-ZnONPs) composite films. The study assessed influence of the various ZnONPs on the morphological, water vapor barrier, color, optical, and antimicrobial properties of the Car-ZnONPs composite films. The surface morphology and UV-blocking attributes of the composite films were affected by the type of ZnONPs used, but their surface color, transparency, and chemical structure remained unaltered. The composite film's thickness and elongation at break (EB) significantly increased, while the tensile strength significantly decreased. In contrast, film's elastic modulus (EM) and water vapor permeability coefficient (WVP) showed no significant difference. All the composite films with added ZnONPs demonstrated potent antibacterial activity against Escherichia coli O157:H7 and Listeria monocytogenes . Among the carrageenan-based composite films, Car-ZnONPs^ZC showed the highest antibacterial and UV-blocking properties, and its elongation at break was significantly higher than that of the pure carrageenan films. This suggests that ZnONPs composite films have the potential to be used as an active packaging film, preserve the safety of the packaged food and extend shelf life.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.263-271
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• 2009

This study evaluated the flocs forming characteristics in the mixing zone to increase the coagulation effect in the drinking water plant. As a measuring tool of formed flocs, on-line particle dispersion analyzer (iPDA) was used in Y drinking water plant. To evaluate the forming flocs, many parameters such as poly amine, coagulant dosing amount, raw water turbidity, and pH was applied in this study. During the periods of field test, poly aluminium chloride (PACl) as a coagulant was used. With the increase of the raw water turbidities, poly amine was also added as one of aids for increasing in coagulation efficiency. The turbidity and pH of raw water was ranged from 7 to 9 and from 25 to 140 NTU, respectively. The increasing of raw water turbidity brought the bigger floc sizes accordingly. From a regression analysis, $R^2$ value was 0.8040 as a function of T, raw water turbidity. Floc size index (FSI) was obtained from a correlation equation as follows; FSI = 0.9388logT - 0.3214 Also, polyamine gave the bigger flocs the moment it is added to the coagulated water in the rapid mixing zone. One of parameters influencing the floc sizes was the addition of powdered active carbon(PAC) in the mixing zone. In case of higher turbidity of raw water, $R^2$ value was 0.9050 in the parameters of [PACl] and [PAC]; FSI = $0.0407[T]^{0.324}[PACI]^{0.769}[PAC]^{0.178}$ On-line floc monitor was beneficial to evaluate the flocs sizes depending on the many parameters consisting raw water properties, bring the profitable basic data to control the mixing zone more effectively.

• (The)Study of the Eastern Classic
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• no.73
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• pp.385-414
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• 2018

In this article, the women as the subject of the family management in the 19th century cataclysm, In particular, I tried to reconstruct the specific life course of a woman who has a status as a jongbu(종부) in the Korean language through the Hangul letter. The Haenam Yoon's the 8th jongbu(종부) Gwangju Lee attempted to find her own unique identity, not the male-centered social order she had learned. Because she had to live a life outside the traditional environment of traditional society because her husband died at the beginning of her marriage. She perceived herself as an independent subject that she had to find and maintain. When Gwangju Lee married and came to the family of Haenam Yun, the economic power of jong-ga(종가) was much inclined. This economic difficulty was caused by the conflict with the slaves and the decrease of tallage(地代) to the change of the slavery system which was the social flow at that time. And uncles of her husband's intervention made the economic situation of the family more difficult. She established her position as a jongbu(종부) and used the right of Adoption option(입후권) of the jongbu(종부) to establish the impoverished family. She chose adoption from distant relatives who were not children of her husband's uncles. Therefore, I was free from her husband uncle's interests. She also believed that it was most important to take control of the economic interests of her family in order to secure her authority as a jongbu(종부). She believed that she had to exercise her economic rights in order to bring slave labor, which is the most important means of sustaining the domestic economy at the time, In the absence of her husband, she established her family in the social upheaval of the nineteenth century, and took her place as a master of a family, not just a family name.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.3
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• pp.32-40
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• 2017

The introduction of neo-Confucianism as the ideological foundation of Joseon, and its root Confucianism have become the origin of the life, scholarship and ideology of the Korean people. Additionally, it was considered the best to follow the teachings of the discipline's advocates including Confucius (孔子), Mencius (孟子), Zisi (子思), ZhuXi (朱子). Among these teachers, ZhuXi was the one who overtly presented the way of self-discipline, of which goal lies in attaining the character by the manifestation of vitality (氣 ki) and rationality (理 i) and contemplating on them. As he regarded natural places with mountains and waters as stages and tools for practicing toward the enlightenment, Confucian scholars in Joseon also followed his example in the spirit of honoring and studying ZhuXi (尊朱子, 學朱子), which became the basic thoughts and practical philosophy among them. Ryu, Junggyo, the neo-Confucian dogmatist, was no exception to applaud the nature, as he designated and ruled Okgye Gugok. On the basis of these backgrounds, this study aims to estimate the geographic places of Okgye Gugok, which was set by Ryu, Junggyo, a Confucian scholar in late-Joseon period, by collecting and analyzing the basic data, starting from Gareung-gun Okgye Sansugi(嘉陵郡玉溪山水記) which is the primary text authored by Seongjae Ryu, Junggyo. The literature study is followed by ten field trips to the estimated locations of Okgye Gugok, and verification of the estimations by three locals who were born and raised in Okgye Gugok. Coordinates and photographs were obtained as spatial data for each location of nine Gok(曲) estimated through this study. They will serve as a primary and critical data for story-telling and tourism resource in Okgye Gugok. The significance of this study is that it provides the primary data for designating the locations of Gok(曲) in Okgyeo Gugok.

• Journal of Adhesion and Interface
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• v.11 no.4
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• pp.149-154
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• 2010

Interfacial evaluation was investigated for single-carbon fiber/phenolic and carbon nanotube (CNT)-phenolic composites by micromechanical technique and electrical resistance measurement combined with wettability test. Compressive strength of pure phenol and CNT-phenolic composites were compared using Broutman specimen. The contact resistance of CNT-phenolic composites was obtained using a gradient specimen by two and four-point methods. Surface energies and wettability by dynamic contact angle measurement were measured using Wilhelmy plate technique. Since hydrophobic domains are formed as heterogeneous microstructure of CNT in the surface, the dynamic contact angle exhibited more than $90^{\circ}$. CNT-phenolic composites exhibited a higher apparent modulus than neat phenolic case due to better stress transferring effect. Work of adhesion, $W_a$ between single-carbon fiber and CNT-phenolic composites exhibited higher than neat phenolic resin due to the enhanced viscosity by CNT addition. It was consistent with micro-failure patterns in microdroplet test.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.43-52
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• 2011

Unnecessary transportation of resources are one of the major causes that adversely affect construction site work productivity. Therefore, layout related studies have been conducted with efforts to develop management technologies and techniques to minimize the resource transportation made at site-level. However, although the necessity for floor-level layout planning studies has been increasing as buildings have become larger and floors have become more complicated, studies to optimize the transportation of materials inside buildings are currently not being actively conducted. Therefore, in this study, a model was developed using genetic algorithms(GA) that will enable the optimization of the locations of finishing materials on the work-floor. With the established model, the arrangement of diverse materials on complicated floors can be planned and the optimized material layout planning derived from the model can minimize the total material transportation time spent by laborers during their working day. In addition, to calculate travel distances between work sites and materials realistically, the concept of actual travel distances was applied. To identify the applicability of the developed model and compare it with existing methodologies and analyze it, the model was applied to actual high-rise residential complexes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1288-1293
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• 2012

Yacon (Smallanthus sonchifolius) contains high amounts of fructooligosaccharides and has been known to promote health of the intestinal tract and to have anti-oxidative and anti-cancer activities. Yacon concentrates were added to make five different pan breads, each with the addition 0% (YE 0), 25% (YE 25), 50% (YE 50), 75% (YE 75), and 100% (YE 100) of yacon concentrates instead of sugar. The higher the yacon concentration in the dough, the more time was needed for the dough to rise. Higher yacon concentration also affected the color of the bread by lowering the L-value and raising the a and b values. The hardness and chewiness of the bread significantly decreased with increasing yacon concentration, while cohesiveness increased. In the bread sensory evaluation, the intensity of crust color, crumb color, yacon flavor, sweetness, yacon taste, moistness, and residual mouth feel were increased with increasing yacon concentrates, while the uniformity of crumb pores slightly decreased. The consumer acceptance of taste, flavor, texture, and overall acceptance were increased with increasing yacon concentrations. As a conclusion, the substitution of yacon concentrates for sugar improved bread quality and increased consumer acceptance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.965-970
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• 2005

In this paper, SPDT Tx/Rx MMIC switch applicable to IEEE 802.11a WLAN systems is designed and fabricated using a specific designed epitaxial layered pHEMT wafer and ETRI's $0.5{\mu}m$ pHEMT switch process. The SPDT switch exhibits a low insertion loss of 0.68dB, high isolation of 35.64dB, return loss of 13.4dB, power transfer capability of 25dBm, and 3rd order intercept point of 42dBm at frequency of 5.8GHz and control voltage of 0/-3V. The comparison of the measured performances with commercial products based on the GaAs pHEMT technology for low voltage operating at ${\pm}$ 3V/0V shows that the return loss is somewhat inferior to the commercial products and insertion loss is compatible with each other however, isolation characteristics are much better than in conventional chips. Based on these performances, we can conclude that the developed SPDT switch MMIC has an enough potential for IEEE802.11a standard 5 GHz-band wireless LAN applications.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.5
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• pp.15-27
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• 2016

This paper examined the effects of youth entrepreneurship on entrepreneurial intention. Especially, we considered scholastic performance as a moderator on the relationship between youth entrepreneurship and their entrepreneurial intention. An empirical analysis on 251 students attending their third year of Suncheon High School revealed the following results. First, the youth entrepreneurship(risk taking, innovativeness and proactiveness) significantly positive affected entrepreneurial intention. The result corresponds to what many preceding studies emphasize, implying that when risk taking, which enables perseverance through uncertain situations, increases; innovativeness, which enables breaking away from existing frameworks, increases; and proactiveness, which creates new opportunities through future-oriented behavior, increase, the entrepreneurial intention of teenagers also increases. Second, a review of the interaction effect of scholastic performance discovered evidence that scholastic performance moderates the relationship between proactiveness and entrepreneurial intention of youth toward a negative(-) direction. In other words, proactiveness positively effects on entrepreneurial intention, but higher scholastic performance imply that such positive tendencies become weakened. The results of the present study will be able to provide significant theoretical and practical implications in carrying out follow-up studies on the youth entrepreneurship, which has been, up to now, relatively neglected.

• Composites Research
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• v.24 no.1
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• pp.45-50
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• 2011

Transparent and conductive carbon nanotube on polyethylene terephthalate (PET) were prepared by dip-coating method for self-sensing multi-functional nanocomposites. The changes in the electrical and optical properties of CNT coating mainly depended on the number of dip-coating, concentration of CNT solution. Consequently, the surface resistance and transmittance of CNT coating were sensitively controlled by the processing parameters. Surface resistance of CNT coating was measured using four-point method, and surface resistance of coated CNT could be better calculated by using the dual configuration method. Optical transmittance of PET film with CNT coating was evaluated using UV spectrum. Surface properties of coated CNT investigated by wettability test via static and dynamic contact angle measurement were consistent with each other. As dip-coating number increased, surface resistance of coated CNT decreased seriously, whereas the transmittance exhibited little lower due to the thicker CNT networks layer. Interfacial microfailure properties were investigated for CNT and indium tin oxide (ITO) coatings on PET substrates by electrical resistance measurement under cyclic loading fatigue test. CNT with high aspect ratio exhibited no change in surface resistance up to 2000 cyclic loading, whereas ITO with brittle nature showed a linear increase of surface resistance up to 1000 cyclic loading and then exhibited the level-off due to reduced electrical contact points based on occurrence of many micro-cracks.