• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.28-34
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• 2006

Laboratory column tests using $Cl^-$ tracer were conducted to study the correlation of soil particle distribution and hydrodynamic dispersion mechanism with three kinds of ununiformed soil samples, in which the ratio of gravel and sand versus silt and clay is 24.5 for S-1 soil, 4.48 for S-2 soil, and 0.4 for S-3 soil. Chloride breakthrough curves with time were fitted with gaussian functions. The relative concentrations of chloride were converged to 1.0 after 0.7 hours for S-1, 6.3 hours for S-2, and 389 hours for S-3. Average linear velocity, longitudinal dispersion coefficient, and longitudinal dispersivity were calculated by chloride breakthrough curves. Longitudinal dispersion coefficients were $1.20{\times}10^{-4}\;m^2/sec$ for S-1, $8.87{\times}10^{-7}\;m^2/sec$ for S-2, and $1.94{\times}10^{-9}\;m^2/sec$ for S-3. Peclet numbers calculated by the molecular diffusion coefficient of chloride and the mean grain diameters of soils were $2.59{\times}10^2$ for S-1, $6.27{\times}10^0$ for S-2, and $1.35{\times}10^{-4}$ for S-3. Mechanical dispersion was dominant for the hydrodynamic dispersion mechanism of S-1. Both mechanical dispersion and molecular diffusion were dominant for the hydrodynamic dispersion mechanism of S-2, but mechanical dispersion was ascendant over molecular diffusion. Hydrodynamic dispersion in S-3 was occurred mainly by molecular diffusion. When plotting three soils on the graph of $D_L/D_m$ versus Peclet number produced by Bijeljic and Blunt (2006), the values of $D_L/D_m$ for S-1 and S-2 were more than 2.0 order compared to their graph. S-3 was not plotted on their graph because the Peclet number was as small as $1.35{\times}10^{-4}$.

• Korean journal of food and cookery science
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• v.25 no.4
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• pp.395-405
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• 2009

In this study, a survey was conducted to determine consumer perceptions and satisfaction for onion hot-water extracts. Among the study subjects, females (53.3%) were in greater number than males, and individuals in their 40s (35.1%) made up the largest group. Cocerning the detailed efficacy of onion hot-water extracts, most respondents (84.5%) were aware of their efficacy and females recognized this more than males (p<0.001). Most consumers (67.3%) purchased onion hot-water extracts from 'health food stores prepared using a double boiler', and many consumers (47.4%) received information on the extracts from families and relatives. Of the respondents, 51.8% said they purchased 'quantities for $1{\sim}3$ months' at one time, and 33.1% stated that the price of onion hot-water extracts was expensive. They considered 'health' the most important aspect when purchasing, and preferred 'pouch packs' (60.3%) and considered 'easiness to open convenience to drink, and safety' (42.0%) the most important product features. Also, 62.8% of the respondents consumed onion hot-water extracts, and many drank them $1{\sim}3$ times a week, with '70 mL' as one dose, and drank them 'regardless of time'. The consumers were satisfied with the listing of health effects, but were not satisfied with the 'taste', 'smell', or 'color' of products. Concerning advertisements for the efficacy of onion hot-water extracts, 72.5% replied 'I trust them a little'. And concerning the expanding onion hot-water extract market, many respondents said it is difficult to choose an onion hot-water extract due to many similar products at the market. They also requested improvements of taste and flavor.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.254-265
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• 2021

As a result of measuring the polyphenol content of Humulus japonicus (HJ) extract according to the collection time and extraction solvent, bothhot water extract and 70% ethanol extract were collected and extracted in June, and the polyphenol content was high. When the harvesting time was the same, the polyphenol content of the ethanol extract was higher than that of the hot water extract. As a result of measuring the antioxidant activity of HJ extract by measuring electron-donating ability, SOD-like activity, and ABTS radical scavenging ability, HJ6E, which has the highest polyphenol content, showed the highest activity. In addition, in the case of the extract collected in August, the polyphenol content was similar. However, the antioxidant activity of the ethanol extract was high, sothe antioxidant activity remained high when extracted with 70% ethanol. As a result of measuring tyrosinase inhibitory activity for evaluating skin whitening activity, HJ6W did not show any activity. The activity at the highest concentration was 16.18% for HJ8W, 8.07% for HJ6E, and 14.7% for HJ8E. Therefore, the content of ingredients showing skin whitening activity was higher in August than in June. In the elastase inhibitory activity for evaluating the anti-wrinkle activityof the skin, the ethanol extract showed very little activity, and the hot water extract did not. In addition, since all extracts do not show astringent activity, it is judged that it is not appropriate to use HJ as a functional ingredient for preventing wrinkle formation. As a result of measuring the cell viability of HJ6E, which showed the highest polyphenol content and antioxidant activity, it showed a cell proliferation effect at low concentrationsbut strong cytotoxicity at concentrations above 50 ㎍/mL. In the case of the NO production inhibitory ability, as the concentration increased, the NO production of Raw 264.7 was suppressed. Theamount of NO production at 1,000 ㎍/mL decreased to 40.7%. However, whether these results are due to cytotoxicity or the extract's efficacy is a part that requires further research.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.440-447
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• 2020

The demand for large-scale horticultural complexes utilizing reclaimed lands is increasing, and one of the pending issues for the construction of large-scale facilities is to establish foundation design criteria. In this paper, we tried to review previous studies on the method of reinforcing the foundation of soft ground. Target construction methods are spiral piles, wood piles, crushed stone piles and PF (point foundation) method. In order to evaluate the performance according to the basic construction method, pull-out resistance, bearing capacity, and settlement amount were measured. At the same diameter, pull-out resistance increased with increasing penetration depth. Simplified comparison is difficult due to the difference in reinforcement method, diameter, and penetration depth, but it showed high bearing capacity in the order of crushed stone pile, PF method, and wood pile foundation. In the case of wood piles, the increase in uplift resistance was different depending on the slenderness ratio. Wood, crushed stone pile and PF construction methods, which are foundation reinforcement works with a bearing capacity of 105 kN/㎡ to 826 kN/㎡, are considered sufficient methods to be applied to the greenhouse foundation. There was a limitation in grasping the consistent trend of each foundation reinforcement method through existing studies. If these data are supplemented through additional empirical tests, it is judged that a basic design guideline that can satisfy the structure and economic efficiency of the greenhouse can be presented.

• The Korean Journal of Archival Studies
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• no.54
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• pp.179-210
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• 2017

By redefining the concept of history, my colleagues and I have reformed our department in terms of curriculum and faculty members. This paper is a report of some of the conclusions that we have obtained from this procedure. Despite a long relationship, two disciplines do not seem to match or complement each other in the Korean education system. We believe that this is due to the fact that the Department of Korean History has focused on "national history (NH)." By conferring a privilege on NH, persons, families, societies, regions, and others were removed from NH. To make matters worse, a biased view that history is just an interpretation has prevailed, and the empiricism of history was weakened, which brought about an indifference in keeping records and archives. In East Asia, "history" means both modern history and archives. The concern about the authenticity of records did not come from H. Jenkinson or L. Duranti, and not even from the electronic environment or the Public Records Act of 1998. Key concepts such as records, documents-archives, manuscripts, authenticity, compilation-appraisal, arrangement, and description are different from their signifiant but are same or similar to their $signifi{\acute{e}}$. In case of "provenance" and "original order," they are used in education and practice in the traditional archives. History includes the recording, archiving, and the story or historiography of an event. In this context, the Department of Korean History should contain a more archives-oriented curriculum and select an archival-trained faculty. On the other hand, the department has accumulated long-term experience with appraisal and description of records; thus, archival science should absorb the criticism of the material. History will be shaken without the help of archives, while archives will lose their root without history. We are at the point in which we need to be reminded why we want to be a historian or an archivist, and for this, the more colleagues, the better.