• The Journal of Engineering Geology
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• v.29 no.3
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• pp.279-288
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• 2019

The groundwater drawdown at each monitoring well near a radial collector well along Anseong Stream, Korea, was measured and compared with the calculated drawdown using the mirror well concept. The drawdown calculation is performed by treating the collector well as a large vertical well in a homogeneous isotropic aquifer. The measured drawdown at each monitoring well is slightly different from the calculated value due to anisotropy in the hydraulic conductivity and aquifer thickness. The difference between the measured and calculated values at Well OW-7 is large, reaching approximately 48 cm, because a horizontal well is not installed along this direction. Sensitivity analysis of the hydraulic conductivity and aquifer thickness indicates that the hydraulic conductivity is more sensitive to groundwater level changes. Groundwater level changes become a concern when a radial collector well with a large pumping rate capacity is installed, which highlights the need to thoroughly investigate the aquifer characteristics in the surrounding area.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.229-238
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• 2021

The selective permeate transport characteristics of iodine ion at follicle cell membrane model in thyroid which irradiated by high energy x-ray(linac 6 MV) was investigated. The follicle cell membrane model used in this experiment was a polysulfonated copolymerized membrane of poly(4-vinylpyridine-co-acrylonitrile:VP-AN). The difference of membrane thickness [2 mole AN%(w/w)], fixed carrier concentration[VP-AN%(w/w)], OH- concentration were occurred at difference of I- concentration and quantity of thyroid hormone, respectively. The tensile strength in fixed carrier concentration[VP-AN% (w/w): 0-62 %] of irradiated membrane was found to be decreased about 1.2-1.8 times than non-irradiated membrane. The I- selective permeate initial flux with increase of membrane thickness [2mole AN%(w/w)], fixed carrier concentration[VP-AN%(w/ w)], OH- concentration in irradiated membrane were found to be decreased about 2.1-4.5 times, about 2.2-2.5 times, about 2.1-2.67 times than non-irradiated membrane, respectively. As a result, the quantity of thyroid hormone was decreased at irradiated membrane than non-irradiated membrane. The decrease of thyroid hormone was occurred at hypothyroidism and hyperthyroidism, thyroid cancer, and so on. As the thyroid hormone in cell membrane model were abnormal, cell damages were appeared at cell.

• Food Engineering Progress
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• v.15 no.4
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• pp.370-375
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• 2011

In this study the polymerase chain reaction (PCR) combined with denaturing gradient gel electrophoresis (DGGE) was evaluated as a method permitting the rapid detection of pathogens in fresh originally grown vegetables. A universal primer (341GCf/534r) was selected for its ability to amplify the V3 region of 16S-rRNA genes in their target pathogens (Salmonella typhimurium, Pseudomonas fluorescens, Bacillus cereus, Listeria monoytogenes, Staphyloocus aureus, E. coli). The 194 bp fragments in PCR were successfully duplicated as expected. The amplified fragments of the same size from six different pathogens also showed good separation upon DGGE. The detection limit of PCR-DGGE for six pathogens in fresh-cut lettuces were over $10^{5}$ CFU/g when sampled by stomaching. However, when the sampling method was changed from stomaching to shaking, the detection limit of six pathogens in organic vegetables was shown to increase by over $10^{1}$ CFU/g, but only those of B. cereus were over $10^{3}$ CFU/g. Therefore, PCR-DGGE was shown to be a reliable method for the detection of pathogens in fresh-cut vegetables.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.105-113
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• 2018

In this study, the engineering properties including bearing capacity of subgrades stabilized with a binder are analyzed by laboratory and field experiments. The main components of the binder are CaO and $SO_3$. After the binder was mixed with a low plasticity clay, the passing rates were relatively decreased as the sieve mesh size increased. Not only did the soil type change to silty sand, but engineering properties, such as the plasticity index and modified California bearing ratio (CBR), were improved for the subgrade. A comparison of the compaction curves of the stabilized subgrade and field soil compacted with the same energy demonstrated an increase of approximately 6% in the maximum dry unit weight, slight decrease in optimum moisture content, and considerable increase improvement in grain size. In the modified CBR test, the effect of unit weight and strength increase of the modified soil (with a specific amount of binder) was remarkably improved. As the proportion of granulated material increased after the addition of binder, the swelling was reduced by 3.3 times or more during initial compaction and 6.5 times by final compaction. The unconfined compressive strength of the specimens was maintained at the homogeneous value with a constant design strength. The stabilized subgrade was validated by applying it in the field under the same conditions; this test demonstrated that the bearing capacity coefficients at all six sites after one day of compaction exceeded the target value and exhibited good variability.

• Korean Journal of Remote Sensing
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• v.34 no.6_2
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• pp.1251-1260
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• 2018

High-quality sea-ice surface models generated from aerial images can be used effectively as field data for developing satellite-based remote sensing methods but also as analysis data for understanding geometric variations of Arctic sea-ice. However, the lack of texture information on sea-ice surfaces can reduce the accuracy of image matching. In this paper, we analyze the performance of matching cost functions for homogeneous sea-ice surfaces as a part of high-quality sea-ice surface model generation. The matching cost functions include sum of squared differences (SSD), normalized cross-correlation (NCC), and zero-mean normalized cross-correlation (ZNCC) in image domain and phase correlation (PC), orientation correlation (OC), and gradient correlation (GC) in frequency domain. In order to analyze the matching performance for texture changes clearly and objectively, a new evaluation methodology based on the principle of object-space matching technique was introduced. Experimental results showed that it is possible to secure reliability and accuracy of image matching only when optimal search windows are variably applied to each matching point in textureless regions such as sea-ice surfaces. Among the matching cost functions, NCC and ZNCC showed the best performance for texture changes.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.4
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• pp.154-159
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• 2019

The glass-ceramic of $Li_2O-Al_2O_3-SiO_2$ system was fabricated by using yttrium oxide and iron oxide that it can reduce the melting temperature and affect the homogenization. Zirconium sulfate was used as a nucleation agent. Calcium phosphate was used to improve the flow the glass so as reduce the viscosity of the glass. The glass-ceramics met a thermal shock test of more than $750^{\circ}C$ and the temperature at which the coefficient of thermal expansion rapidly increased at over $800^{\circ}C$ was shifted by about the above $30^{\circ}C$. Therefore, it is concluded that the glass-ceramic of $Li_2O-Al_2O_3-SiO_2$ system with yttrium oxide and iron oxide was founded to have good melting conditions and excellent thermal expansion resistance at high temperature such as special field for kitchen utensils.

• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.4
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• pp.141-150
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• 2022

To abate the environmental burden derived from the massive generation of cattle manure (CM), pyrolysis of CM was suggested as one of the methods for manure treatment. In respect of carbon utilization, pyrolysis has an advantage in that it can produce usable carbon-based chemicals. This study was conducted to investigate a syngas production from pyrolysis of CM in CO₂ condition. In addition, mechanistic functionality of CO₂ in CM pyrolysis was investigated. It was found that the formation of CO was enhanced at ≥ 600 ℃ in CO2 environment, which was attribute to the homogeneous reactions between CO₂ and volatile matters (VMs). To expedite reaction kinetics for syngas production during CM pyrolysis, Catalytic pyrolysis was carried out using Co/SiO2 as a catalyst. The synergistic effects of CO₂ and catalyst accelerate the formation of H₂ and CO at entire temperature range. Thus, this result offers that CO₂ could be a viable option for syngas production with the mitigation of greenhouse gas.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.247-258
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• 2020

In this paper, based on a stochastic parallel gradient descent (SPGD) algorithm we study phase control of a coherent-beam-combining system under turbulent atmospheric conditions. Based on the statistical theory of atmospheric turbulence, we carry out the analysis of the phase and wavefront distortion of a laser beam propagating through a turbulent atmospheric medium. We also conduct numerical simulations of a coherent-beam-combining system with 7- and 19-channel laser beams distorted by atmospheric turbulence. Through numerical simulations, we characterize the phase-control characteristics and efficiency of the coherent-beam-combining system under various degrees of atmospheric turbulence. It is verified that the SPGD algorithm is capable of realizing 7-channel coherent beam combining with a beam-combining efficiency of more than 90%, even under the turbulent atmospheric conditions up to cn2 of 10-13 m-2/3. In the case of 19-channel coherent beam combining, it is shown that the same turbulent atmospheric conditions result in a drastic reduction of the beam-combining efficiency down to 60%, due to the elevated impact of the corresponding refractive-index inhomogeneity. In addition, by putting together the number of iterations of the SPGD algorithm required for phase locking under atmospheric turbulence and the time intervals of atmospheric phenomena, which typically are of the order of ㎲, it is estimated that hundreds of MHz to a few GHz of computing bandwidth of SPGD-based phase control may be required for a coherent-beam-combining system to confront such turbulent atmospheric conditions. We expect the results of this paper to be useful for quantitatively analyzing and predicting the effects of atmospheric turbulence on the SPGD-based phase-control performance of a coherent-beam-combining system.

• Journal of the Korean Geotechnical Society
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• v.36 no.12
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• pp.45-56
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• 2020

In this paper, intelligent compaction (IC) technology and the earthwork quality control specifications based on IC were analyzed, and the field study was conducted to investigate the relationship between the representative IC value CMV (Compaction Meter Value) and spot test results (plate bearing test and field density test). As the number of roller passes increased, both the CMV and spot test results increased. However, point-by-point comparison between CMV and spot test results yielded poor quality correlations; this is because the ununiform stiffness of the underlying layer and the moisture content of the lift layer affected the CMV and spot test results, respectively. Most international specifications related to IC requires knowledge of the IC values and their relationships with the soil properties obtained by the traditional spot tests. Therefore, for the successful implementation of intelligent compaction technology into earthwork construction practice, the number of roller passes as well as the lift thickness and the moisture content of the soil should be carefully considered.

• Journal of Environmental Impact Assessment
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• v.30 no.1
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• pp.1-12
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• 2021

This study focused on verifying the identification of freshwater fish species in Korea using Environmental DNA (eDNA) technique. The research of DNA is increasing in the field of ecology, since this is more sensitive of identify rather than traditional investigation method. Which is difficult to detect species hidden in water and be easily influenced by diverse factors (sites, bad weather, researchers and so on). We applied the pilot test in aquarium (Freshwater Fish Ecological Learning Center in Yangpyeong, Gyeonggi Do), where freshwater fish species are inhabits. We conducted to sampling and analyzing the sixteen water samples (50 species from 7 orders and 13 families) using MiFish primer set. The results showed that 45 species (90%) was investigated by eDNA. It highlight that eDNA with universal primer is possible to detect freshwater fish species of Korean. However, the errors on species identification seems to be caused by the primer that be not suited perfectly and the pollution such as aquarium, sampling collectors.