• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.55.1-55.1
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• 2010

Cost efficient and large area deposition of superior quality $Al_2O_3$ doped zinc oxide (AZO) films is instrumental in many of its applications including solar cell fabrication due to its numerous advantages over ITO films. In this study, AZO films were prepared by a highly efficient rotating cylindrical dc magnetron sputtering system using AZO target, which has a target material utilization above 80%, on glass substrates in argon ambient. A detailed analysis on the electrical, optical and structural characteristics of AZO thin films was carried out for solar cell application. The properties of films were found to critically depend on deposition parameters such as sputtering power, substrate temperature, working pressure, and thickness of the films. A low resistivity of ${\sim}5.5{\times}10-4{\Omega}-cm$ was obtained for films deposited at 2kW, keeping the pressure and substrate temperature constant at 3 mtorr and $230^{\circ}C$ respectively, mainly due to an increase in carrier mobility and large grain size which would reduce the grain boundary scattering. The increase in carrier mobility with power can be attributed to the columnar growth of AZO film with (002) preferred orientation as revealed by XRD analysis. The AZO films showed a high transparency of>87% in the visible wavelength region irrespective of deposition conditions. Our results offers a cost-efficient AZO film deposition method which can fabricate films with significant low resistivity and high transmittance that can find application in thin-film solar cells.

• Communications of Mathematical Education
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• v.28 no.1
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• pp.97-130
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• 2014

The purpose of the study was to investigate the aspects of analogy of high school student's thinking process revealed in the inquiry activity with synthetic division. The case study method of qualitative research was conducted with two high school 10th grade students. Structure-mapping model(SMM) of Gentner and similarity frames which were proposed by other researchers were utilized to analyze the data. Two students used analogy as a tool and they could discover synthetic division of more than 2 degrees, but they revealed different levels of mathematics discovery depending on the different degree of analogical thinking. Surface similarity in the process of inquiry activity played a vital role in analogical thinking. We asked students to explore and discover analogy based on structure similarity. Analogy based on the systematic approach made it possible to predict upper domain. Analogy based on the procedure similarity induced internalization. We could conclude that analogy has instrumental, heuristic and reflective characteristics.

• Food Science of Animal Resources
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• v.35 no.4
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• pp.557-563
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• 2015

The present study was carried out to investigate the effects of soy protein hydrolysates (SPHs) addition on the quality characteristics of pork patties. The SPHs was prepared by subcritical water process (SWP) at 180℃ without holding time and mixed with the pork patty components at varying concentrations (0-3%), and the patties were stored at 4℃ for 14 d. As quality parameters, instrumental color, thiobarbituric acid-reactive substances (TBARS), pH, water holding capacity (WHC) and shear force were measured at the end of storage. Regardless of SPHs concentration, the addition of SPHs significantly manifested low L* and high a* values compared to those of untreated control (p<0.05). For b* value, addition of SPHs in the 0.5-1.5% was unaffected, while >2.0% of SPHs caused significantly lower b* than control (p<0.05). The color changes in pork patties with and without SPHs were also identified in visual appearance where the pork patties containing 0.5-2.0% showed bright red color which was comparable to brownish color of control and patties containing >2.5% SPHs. Lipid oxidation was delayed by the addition of 0.5-1.5% SPHs, while it was accelerated by the addition of 3% SPHs. The pH of patties increased with increasing concentration of SPHs, whereas there were no significant differences in WHC and shear force of patties. Consequently, the results indicated that the addition of 0.5-1.5% SPHs had a potential advantage in suppressing oxidative deterioration of fat-containing meat products during chilled storage.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.95.2-96
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• 2003

In order to develop a new microbial fungicide for the control of vegetable diseases using endophytic bacteria, a total of 260 bacterial strains were isolated from fresh tissues of 5 plant species. After they were cultured in broth media, their antifungal activities were screened by in vivo bioassays against Botrytis cinerea(tomato gray mold), Pythium ultimum(cucumber damping-off), Phytopkhora infestans(tomato late blight), Colletotrichum orbiculare(cucumber anthracnose), and Blumeria graminis f. sp. hordei(barley powdery mildew). As the results of screening, 38 bacterial strains showed potent antifungal activities against at least one of 5 plant pathogens. A bacterial strain EB072 displayed potent disease control activities against 3 plant diseases. Among the bacterial strains with a potent antifungal activity against cucunlber anthracnose, three bacterial strains, EB054, EB151 and EB215, also displayed a potent in vitro antifungal activity against C. acutatum, a fungal agent causing pepper anthracnose. A bacterial strain EB215 obtained from roots of cucumber was identified as Burkholderia cepacia based on its physiological and biochemical characteristics and 165 rRNA gene sequence. An antifungal substance was isolated from the liquid cultures of B. cepacia EB215 strain by ethyl acetate partitioning, repeated silica gel column chromatography, and invitro bioassay, Its structural determination is in progress by various instrumental analyses.

• Analytical Science and Technology
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• v.9 no.1
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• pp.20-25
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• 1996

Trace levels of uranium and thorium in geologic samples are determined rapidly by a direct wavelength-dispersive X-ray fluorescence method. Relative intensity of scattered tube radiation was used as an internal standard to compensate for variations in instrumental operating characteristics. U and Th can be determined within a precision of ${\pm}10%$ and accuracy of ${\pm}15%$ or less with measuring times of 50 seconds for Th and 400 seconds for U, respectively. The results of XRF analysis were in good agreement with those of other methods such as nutron activation analysis and inductively coupled plasma atomic emission spectrometry.

• Journal of Food Hygiene and Safety
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• v.10 no.2
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• pp.111-131
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• 1995

Quality changes of sausages in refrierated storage for 60 days were investigated. Nine types of sausages produced in Korea were stored at 4$^{\circ}C$(3~5$^{\circ}C$), and then chemical, microbiological, and sensory characteristics were evaluated on every 10 days. The proximate analysis showed considerable variation in fat (23.97%, 17.10~30.20%) with less variation in moisture (51.96%, 48.10~56.30%) and protein (12.96%, 11.40~13.95%), pH value decreased over time averaging from 6.31 to 6.22 with no significant difference. Water activity was consistent over refrigerated storage averaging 0.95. Volatile basic nitrogen (VBN) values were still within 20 mg% though VBN for all types significantly increased over time (p<0.05). Thiobarbituric acid (TBA) values were well below 1.0 though TBA showed significant differences among storage periods (p<0.05). Standard plate counts (SPCs) significantly increased during storage (p<0.05) while coliform group was not counted in all cases. SPCs reached 104 CFU/g in two types after 50 days' storage and were below 105 CFU/g in all types after 60 days' storage. Instrumental texture analysis showed that springiness, adhesiveness, and hardness signficantly decreased over time (p<0.05) while no change was observed in external color. significantly decreased over time the 60-day storage period (p<0.05) while cohesiveness, chewiness and gumminess did not change. Lightness, redness and yellowness of the internal Hunter color significantly decreased over time (p<0.05) while no change was observed in external color. Sensory profile showed that flavor, taste, texture and overall acceptable after 60 days' storage at 4$^{\circ}C$. However, the shelf-life of the samples should be decided in the consideration of the growth rate other spoilage flora coupled with the bacterial growth after 50 days' storage.

• Food Science of Animal Resources
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• v.34 no.1
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• pp.99-105
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• 2014

The aim of this study is to evaluate the availability of salted and fermented fish (SFF) including salted and fermented anchovy (SFA) and shrimp (SFS) as a marinade of beef jerky. In curing solutions, half (SFA 1 and SFS 1) or whole (SFA 2 and SFS 2) salt-water was replaced with SFF juices. Higher water activity ($a_w$) was found in the beef jerky cured with SFFs than the control (C) (p<0.05). The SFFs had the effect of causing a decrease in hardness and an increase in cohesiveness (p<0.05). Among the treatment samples, springiness was the highest in SFA2 and SFS2 (p<0.05) and the lowest values of Warner-Bratzler shear force were found in SFA1 and SFA2 (p<0.05). The SFFs also had the effect of increasing the flavor of the sensory properties; however, color measurements from both the instrumental surface color ($L^*$, $a^*$, $b^*$, chroma, and hue angle) and color of sensory evaluation were decreased by addition of SFFs (p<0.05). Therefore, we conclude the SFFs can improve the texture and sensory properties of the beef jerky. In particular, the SFS is a good ingredient for the curing solution. However, studies are still needed on improving the $a_w$, pH, and surface color of the beef jerky to apply the SFFs for making beef jerky.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.251-258
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• 2018

We investigated microbial and quality changes in wrap-packaged dry-aged beef after completion of aging and subsequent storage in a refrigerator. After 28 days of dry aging (temperature, $4^{\circ}C$; RH, approximately 75%; air flow velocity, 2.5 m/s), sirloins were trimmed, wrap-packaged, and stored at $4^{\circ}C$ for 7 days. Analyses of microbial growth, pH, volatile basic nitrogen (VBN), 2-thiobarbituric acid-reactive substance (TABRS), and instrumental color, myoglobin, and sensory evaluation were conducted on days 0, 3, 5, and 7. The results show that the number of total aerobic bacteria (TAB), yeast, and lactic acid bacteria increased with an increase in storage days, whereas no change in the growth of mold was observed during 7 days of storage. Based on the legal standard for TAB count, the estimated shelf-life of wrap-packaged dry-aged beef was predicted to be less than 12.2 days. However, the shelflife should be less than 6.3 days, considering the result of sensory quality (odor, taste, and overall acceptance). No significant change in visible appearance was also observed during 7 days of storage. The results suggest that the present quality indicators for meat spoilage (pH, VBN, and TBARS) should be re-considered for dry-aged beef, as its characteristics are different from those of fresh and/or wet-aged beef.

• The Korean Journal of Community Living Science
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• v.18 no.1
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• pp.71-85
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• 2007

This study investigates differences by type of caregiving using data on three groups of caregivers, 177 from home stay situations, 189 from day care centers, and 138 from nursing homes. First, the result shows that characteristics of both caregivers and elders differ by type of caregiving. Second, caregivers in the home stay situation have the highest caregiving burden of the three groups. Third, from examination of the related variables, the caregiving burden of home stay caregivers is affected by family income, caregivers' health, type of job, and whether or not the elder has symptoms of dementia. Also, the study reveals that emotional services for elders reduce the aggravation of family relations and economic burden, but that instrumental services highly increase economic burden. It reveals that caregivers of elders in day care centers, especially those who are in bad health, are more likely to experience feelings of constriction, aggravation of family relations and economic burden. On the other hand, caregivers who receive more emotional services have better experiences in family relations, including relations with the elder. In case of the elders of nursing homes, if the main caregiver is a daughter-in-law, aggravation of family relations is higher than if the main caregiver is a spouse. Finally, the caregiver's burden is affected by their own health and income, and by whether the elder has symptoms of dementia or stroke.

• Journal of Korean Academy of Nursing Administration
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• v.2 no.2
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• pp.85-95
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• 1996

The purpose of this study was to investigate moral reasoning among 77 senior medical students. Data were collected through selfreported questionnaires in June, 1995. The short form of the DIT (Rest's Defining Issues Test) was adopted to measure the stage of moral development, which was classified with the stage 2(instrumental relativist orientation), the stage 3(interpersonal concordance), the stage 4(law and order), the stage 5A(societal consensus), and the stage 5B(intuitional humanism), stage 6(universal ethical practice). In particular, the level of principled thinking(P) was measured by summing those scores of the stages 5A, 5B, and 6. The possible range of P is O to 95. The data were analyzed by t-test, ANOVA. The results were as follows. 1. The mean score of P(%) was 44.67 (SD=12.82). And the mean score of the stage 5A was higher than the scores of other stages. The mean score of P was not significantly different by general characteristics of the students. 2. The mean score of the stage 5B revealed significant difference by religion (3.17, P=.019) ; The score was highest in buddhist (8.0), which was followed by protestant (6.1), catholic (5.6) and no religion (4.7). 3. The mean score of the stage 4 revealed significant difference by educational background of mother (3.24, P=.017) ; the Score was highest in graduate school (25.0), which was followed by high school (14.1), under-graduate school (13.9), elementary school (12.4), middle school (8.3).