• Korean Journal of Remote Sensing
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• v.22 no.6
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• pp.507-518
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• 2006

The radiation at $11{\mu}m$ absorbed more than at $12{\mu}m$ when aerosols is loaded in the atmosphere, whereas it will be the other way around when cloud is present. The difference of the two channels provides an opportunity to detect aerosols such as Yellow Sand even with the presence of clouds and at night. However problems associated with this approach arise because the difference can be affected by various atmospheric and surface conditions. In this paper, we has analyzed how the threshold and sensitivity of the brightness temperature difference between two channel (BTD) vary with respect to the conditions in detail. The important finding is that the threshold value for the BTD distinguishing between aerosols and cloud is $0.8^{\circ}K$ with the US standard atmosphere, which is greater than the typical value of $0^{\circ}K$. The threshold and sensitivity studies for the BTD show that solar zenith angle, aerosols altitude, surface reflectivity, and atmospheric temperature profile marginally affect the BTD. However, satellite zenith angle, surface temperature along with emissivity, and vertical profile of water vapor are strongly influencing on the BTD, which is as much as of about 50%. These results strongly suggest that the aerosol retrieval with the BTD method must be cautious and the outcomes must be carefully calibrated with respect to the sources of the error.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.634-639
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• 2021

This study investigated the effects of cold plasma (CP) treatment on the properties of biopolymer films prepared with defatted mustard meal (DMM films). CP treatments using N₂, O₂, He, Ar, and dry air did not affect the tensile properties, water vapor permeability, color, and morphology of DMM films, whereas the treatments using He and Ar improved their printability. The tensile strength (TS) of O₂- or air-CP-treated DMM films and the elastic modulus (EM) of O₂-, He-, Ar-, or air-CP-treated films were lower than those of the untreated films. An increase in the power of Ar-CP treatment resulted in an increase in EM. The optimum treatment power and time for minimizing yellowness changes by Ar-CP treatment were 420 W and 40 min, respectively. The results demonstrated the potential application of CP treatment to improve the film properties of DMM films and possibly other agricultural by-product-based biopolymer films, making the films more applicable to food packaging.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.1
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• pp.1-7
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• 2019

In this study, we estimated the tropospheric delay of GNSS (Global Navigation Satellite System) signals during passing through the atmosphere in relation to weather and seasonal factors. For this purpose, we chose four CORS (Continuously Operating Reference Station) stations from inland (CCHJ and PYCH) and on the coast (GEOM and CHJU). A total of 48 days for each station (one set of data for each week) were downloaded from the NGII (National Geographic Information Institute) and processed it using the scientific GNSS software. The average tropospheric delays in winter are less than 2,400 mm, which is about 200 mm less than those in summer. The estimated tropospheric delay shows a similar pattern from all stations except the absolute bias in magnitude, while a large delay was observed for the station located on the coast. In addition, the delay during the day was relatively stable in winter, and the average tropospheric delay was strongly related to the orthometric height. The inland stations have tropospheric delays by the precipitation rather than humidity due to dry weather and difference in temperature. On the contrary, it was primarily caused by the humidity on the sea. The correlation between temperature and water vapor pressure is 0.9 or larger for all stations, and the tropospheric delay showed a high linear relationship with temperature. It is necessary to analyze the GNSS data with higher temporal resolution (e.g. all RINEX data of the year) to improve the stability and reliability of the correlation results.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.981-996
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• 2018

In agriculture, remote sensing data using earth observation satellites have many advantages over other methods in terms of time, space, and efficiency. This study analyzed the changes of reflectance and vegetation index according to atmospheric correction of images before using satellite images in agriculture. Top OF Atmosphere (TOA) reflectance and surface reflectance through atmospheric correction were calculated to compare the reflectance of each band and Normalized Vegetation difference Index (NDVI). As a result, the NDVI observed from field measurement sensors and satellites showed a higher agreement and correlation than the TOA reflectance calculated from surface reflectance using atmospheric correction. Comparing NDVI before and after atmospheric correction for multi-temporal images, NDVI increased after atmospheric corrected in all images. garlic and onion cultivation area and forest where the vegetation health was high area NDVI increased more 0.1. Because the NIR images are included in the water vapor band, atmospheric correction is greatly affected. Therefore, atmospheric correction is a very important process for NDVI time-series analysis in applying image to agricultural field.

• Korean Journal of Heritage: History & Science
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• v.42 no.4
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• pp.4-19
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• 2009

Though admitting that, in light of the recent archaeological trend, the excavation on relics of Sam-gama (a sort of kiln steaming the hemp) is increasingly reported, little efforts by far have been made not only to restore its traditional structure design but also to research hardly the change of hemp-steaming technologies in ages. In this regard, this paper shows the exploration of structural method and design as well as operability with regard to Sam-gut, traditional hemp-processing equipment that was recently reconstructed in Jungsun, Kangwon Province. Samgut, generally positioned at the waterside area, is an traditional device for steaming hemp to get bast fibers from the raw material of hemp, principally consisting of HWA-JIP(fire-place) to obtain steams by feeding fire ad Mong-got(boiling chamber) to make the hemp steamed after stacking. More specifically, thick round-logs were piled at the bottom of Hwajip prior to stacking stones around its circumferential area. When the timber positioned below gets burned with high temperature to heat stones existing in the upper side, waters then poured onto it after laying a bundle of grass and soil up to the boiled stones. If so, there generates hot vapor, which is conveyed to Monggot to steam the hemp. Functionally, it is of outstanding importance that Samgut is capable of producing high-temperature water vapors instantaneously under the intensive manpower, thus being constructed achievable for those purposes. The Samgut made by digging the ground is an instant facility that is closed after use. The remains, which were used to generate higher thermal power for steaming hemp, make it hard to excavate the historic traits because there left little vestiges in the soil, which means keen attention must be paid to find out the trace of Smgama relics. Future research stall be focused on collection of broader data regarding Samgut including technological review in extracting bas fibers from the hemp.

• Journal of the Korean earth science society
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• v.41 no.6
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• pp.684-694
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• 2020

In this study, we developed a rubric for assessing middle school students' conceptual understanding about dew point. For this purpose, we analyzed 9th grade students' responses collected by using a multi-tiers constructed-response item of National Assessment of Educational Achievement (NAEA) and classified the types of the responses according to their characteristics. In addition, we analyzed the distribution of student response types according to mean achievement scores and developed an assessment rubric of conceptual understanding about dew point. The findings are as follows: First, the analysis of student responses to finding dew point in the saturation curve showed that many students had no or lack understanding of the scientific concept of dew point. Second, as a result of analyzing the student response to the water vapor condensation process at dew point, the proportion of scientific conception types was very low, while the proportion of misconception types was relatively high and the types varied as well. Third, a four- level assessment rubric was developed based on the analysis of the distribution of student response types according to the mean achievement scores. Based on the findings, we suggested the development and utilization of assessment rubric in the field of Earth science education.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.3
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• pp.257-266
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• 2021

This study investigated the understanding of pre-service teachers in relation to the 'fog experiment' in the 5th grade 'Weather and Our Daily Life' unit of the 2009 and 2015 revised elementary school science textbooks. Pre-service teachers who participated in this study were 100 students, who are attending the university of education and taking courses in teaching research. After pre-learning about the 2009 and 2015 revised elementary school science textbooks and guide book, pre-service teachers conducted the experiment in groups. After that, the pre-service teachers individually presented answers to three questions, and the results of analyzing the answers are as follows. First, there were 24 (24%) preservice teachers who explained the difference in fog generation in the 2009 and 2015 revised curriculum with related scientific concepts such as condensation and water vapor, and only 1 (1%) of them explained the difference using the concept of saturation. Second, there were 48 (48%) pre-service teachers who found out the reason for the change in the fog experiment method according to the change in the curriculum. Third, pre-service teachers valued the reproduction and success of experiments rather than the importance of scientific knowledge, and such pre-service teachers suggested the use of alternative experiments or website.

• Korean Journal of Food Science and Technology
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• v.54 no.3
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• pp.327-333
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• 2022

An orally disintegrating film (ODF) based on hyaluronic acid (HA) containing vitamin D was developed. The vitamin D content in the ODF was set based on the adequate intake (AI) of vitamin D from 0 to 10 AI (0, 1, 4, 7, and 10AI). The control (0AI) had the highest thickness and showed the longest disintegration time among the samples. The moisture content of the ODFs was significantly lower in those with vitamin D compared to the control. As the amount of vitamin D increased, the water vapor permeability (WVP) of the ODFs decreased, and the opacity significantly increased. The tensile strength was higher in the films containing vitamin D compared to the control films. However, the elongation at the break showed no significant difference among the films. The vitamin D content in the film was reduced by 25.7-44.2% during processing compared to the amount that was originally added. Based on the above results, a new and convenient vitamin D delivery system, an ODF, could be successfully produced.

• Clean Technology
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• v.16 no.2
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• pp.132-139
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• 2010

The Cu-Mn mixed oxide catalysts with different molar ratios of Cu/(Cu+Mn) prepared by co-precipitation method have been investigated in CO oxidation at $30^{\circ}C$. The catalysts used in this study were characterized by X-ray Diffraction (XRD), $N_2$ sorption, X-ray photoelectron spectroscopy (XPS), and $H_2$-temperature programmed reduction $(H_2-TPR)$ to correlate with catalytic activities in CO oxidation. The $N_2$ adsorption-desorption isotherms of Cu-Mn mixed oxide catalysts showed a type 4 having pore range of 7-20 nm and BET surface area was increased from 17 to $205\;m^2{\cdot}g^{-1}$ with increasing of Mn content. The XPS analysis showed the surface oxidation state of Cu and Mn represented $Cu^{2+}$and the mixture of $Mn^{3+}$ and $Mn^{4+}$, respectively. Among the catalysts studied here, Cu/(Cu+Mn) = 0.5 catalyst showed the highest activity at $30^{\circ}C$ in CO oxidation and the catalytic activity showed a typical volcano-shape curve with respect to Cu/(Cu+Mn) molar ratios. The water vapor showed a prohibiting effect on the efficiency of the catalyst which is due to the competitive adsorption of carbon monoxide on the active sites of catalyst surface and finally the formation of hydroxyl group with active metals.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.91-101
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• 1993

To predict accurately the thermal hydraulic behavior of light water reactors during normal or abnormal operation, the accurate estimation of the void distribution is required. Up to date, many techniques for predicting void fraction of two-phase flow systems have been suggested. Among these techniques, the drift-flux model is widely used because of its exact calculation ability and simplicity. However, to get more accurate prediction of void fraction using drift-flux model, slip and flow regime effects must be considered more properly In the drift-flux method, these two effects are accounted for by two drift-flux parameters ; $C_{o}$ and (equation omitted). At earlier stage, $C_{o}$ is measured in a circular tube. In this study, $C_{o}$ is experimentally determined by measuring local void fraction and vapor velocity distribution in a rectangular subchannel having 4 heating rods which simulates nuclear subchannels. The measurements are peformed with two-electrical conductivity probes which are known to be adequate for measuring local parameters. The experiments are performed at low flow rate and the system pressure less than 3 atmo spheric pressure. In this experiment, (equation omitted), is not measured, but quoted from well-known empirical correlation to formulate $C_{o}$. Finally, $C_{o}$ is expressed as a function of channel averaged void fraction. fraction.