• Journal of Food Hygiene and Safety
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• v.33 no.6
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• pp.466-473
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• 2018

An analytical method of sodium polyacrylate in processed food products was developed and monitored by using size-exclusion chromatography. GF-7M HQ column and UV/VIS detector were selected based on peak shape and linearity. Flow rate, column oven temperature, and mobile phase were selected as 0.6 mL/min, $45^{\circ}C$, and 50 mM sodium phosphate buffer of pH 9.0, respectively. Samples for analysis of sodium polyacrylate were extracted with 50 mM sodium phosphate buffer of pH 7.0 for 3 hr at $20^{\circ}C$ and 150 rpm. Analytical method validation revealed proper selectivity and calibration curve was selected in the range of 50-500 mg/L, and correlation coefficient of calibration curve was more than 0.9985. Limit of detection of sodium polyacrylate was 10.95 mg/kg and limit of quantification was 33.19 mg/kg. Accuracy and coefficient of variation for sodium polyacrylate analysis was 99.6-127.6%, 3.0-8.3% for intra-day and 94.3-121.9%, 1.3-2.6% for inter-day, respectively. Sodium polyacrylate was detected in 40 samples among monitored 125 processed food products. Detected contents were less than 0.2%, limited by the Food Additives Code. Results suggest the established size-exclusion chromatography method could be used to analyze sodium polyacrylate in processed food products.

• Korean Journal of Heritage: History & Science
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• v.47 no.4
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• pp.224-243
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• 2014

This study examined the materials and casting technology(cast, alloy, etc.) used in the manufacturing of bronze artifacts based on old literature such as Yongjae Chonghwa, Cheongong Geamul, and The Korea Review. In the casting experiment for restoration of Sangpyong Tongbo, a bronze and brass mother coin mold was made using the sand mold casting method described in The Korea Review. The cast was comprised of the original mold plate frame, wooden frame, and molding sand. Depending on the material of the outer frame, which contains the molding sand, the original mold plate frame can be either a wooden frame or steel frame. For the molding sand, light yellow-colored sand of the Jeonbuk Iri region was used. Next, the composition of the mother alloy used in the restoration of Sangpyong Tongbo was studied. In consideration of the evaporation of tin and lead during actual restoration, the composition of Cu 60%, Zn 30%, and Pb 10% for brass as stated in The Korea Review was modified to Cu 60%, Zn 35%, and Pb 15%. For bronze, based on the composition of Cu 80%, Sn 6%, and Pb 14% used for Haedong Tongbo, the composition was set as Cu 80%, Sn 11%, and Pb 19%. The mother coin mold was restored by first creating a wooden father coin, making a cast from the wooden frame and basic steel frame, alloying, casting, and making a mother coin. Component analysis was conducted on the mother alloy of the restored Sangpyong Tongbo, and its primary and secondary casts. The bronze mother alloy saw a 5% increase in copper and 4% reduction in lead. The brass parent alloy had a 5% increase in copper, but a 4% and 12% decrease in lead and tin respectively. Analysis of the primary and secondary mother coin molds using an energy dispersive spectrometer showed that the bronze mother coin mold had a reduced amount of lead, while the brass mother coin mold had less tin. This can be explained by the evaporation of lead and tin in the melting of the primary mother coin mold. In addition, the ${\alpha}$-phase and lead particles were found in the mother alloy of bronze and brass, as well as the microstructure of the primary and secondary coin molds. Impurities such as Al and Si were observed only in the brass mother coin mold.

• Journal of Environmental Impact Assessment
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• v.30 no.2
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• pp.117-131
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• 2021

Urban development is continuously being carried out to stabilize housing supply. The importance of ecosystem services assessments considering the various urban spatial structures is emerging as land use change in the wake of urban development has impact on the provision of ecosystem services. However, few studies are available as to the effects of land use transition in agricultural land due to urban development on ecosystem services. The purpose of this study is to examine the applicability of decision-making in the urban planning process by analyzing the impact of land use change on ecosystem services due to urban development. Therefore, the scenario was set on before and after the city development, targeting Namyangju Wangsuk Zone 1 and InVEST model was used to compare and analyze changes in value of ecosystem services. Analysis results of ecosystem services before the urban development, it turned out that habitat quality and water yield increased overtime but carbon storage and crop production decreased. Analysis results of ecosystem services after the urban development indicated that all items in ecosystem services by scenario decreased more than in 2018. Among the scenarios of urban development, compact city had the lowest value of water resource supply but had the highest value in terms of habitat quality, carbon storage amount, and crop production. The study results demonstrate that the compact city has positive effects on ecosystem services and is expected to be used as the basic data for supporting policy decision-making in the establishment of future urban development and management plans.

• Journal of Intelligence and Information Systems
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• v.28 no.2
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• pp.191-206
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• 2022

Recently, it is a de-facto approach to utilize a pre-trained language model(PLM) to achieve the state-of-the-art performance for various natural language tasks(called downstream tasks) such as sentiment analysis and question answering. However, similar to any other machine learning method, PLM tends to depend on the data distribution seen during the training phase and shows worse performance on the unseen (Out-of-Distribution) domain. Due to the aforementioned reason, there have been many efforts to develop domain-specified PLM for various fields such as medical and legal industries. In this paper, we discuss the training of a finance domain-specified PLM for the Korean language and its applications. Our finance domain-specified PLM, KB-BERT, is trained on a carefully curated financial corpus that includes domain-specific documents such as financial reports. We provide extensive performance evaluation results on three natural language tasks, topic classification, sentiment analysis, and question answering. Compared to the state-of-the-art Korean PLM models such as KoELECTRA and KLUE-RoBERTa, KB-BERT shows comparable performance on general datasets based on common corpora like Wikipedia and news articles. Moreover, KB-BERT outperforms compared models on finance domain datasets that require finance-specific knowledge to solve given problems.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.319-331
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• 2023

Aminoglycoside antibiotics, also known as aminoglycosides (AGs), are veterinary drugs effective against a wide range of gram-negative and gram-positive bacteria. Owing to their recent use in cultured meats, it has become essential to establish an analytical method for safety management. AGs are highly polar compounds, and ion-pair reagents (IPRs) are used to ensure component separation. Owing to the high possibility of potential mechanical problems resulting from IPR addition to the mobile phase, an analytical method in which IPRs are added directly to the vial was explored. In this study, methods for analyzing 10 AGs via liquid chromatography-tandem mass spectrometry (LC-MS/MS) with the addition of two IPRs were validated for selectivity, detection limit, quantitation limit, recovery, and precision. The detection limit was 0.0001-0.0038 mg/kg, the quantification limit was 0.004-0.011 mg/kg, and the linearity (R²) within the concentration range of 0.01-0.5 mg/kg was over 0.99. Recovery and precision (expressed as relative standard deviation) evaluated in the two matrices (beef and cell culture media) ranged from 70.7% to 120.6% and 0.2% to 24.7%, respectively. The validated AG analytical method was then applied to 15 meats prepared from chicken, beef, and pork, and 6 culture media and additives used in cultured meat. No AGs were detected in any of the 15 meats distributed in Korea; however, streptomycin and dihydrostreptomycin were detected at levels ranging from 695.85 to 1152.71 mg/kg and 6.35 to 11.11 mg/kg, respectively, in the culture media additives. The LC-MS/MS method coupled with direct addition of IPRs to the vial can provide useful basic data for AG analysis and safety evaluation of meats as well as culture media and additives for cultured meats.

• The Korean Journal of Nuclear Medicine
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• v.32 no.1
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• pp.71-80
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• 1998

This study examines the levels of carbohydrate antigen 19-9(CA19-9) and cancer antigen 125(CA125) in serum and its related factors in healthy Korean population. Although CA19-9 and CA125 have been widely used tumor markers for gastroenteric cancers and ovarian cancer in Western countries, there are no information available on the serum levels of CA19-9 and CA125 in healthy population and the factors affecting the levels of these tumor markers in Korea. A cross-sectional study was performed to measure CA19-9 and CA125 among 76 healthy males and 95 healthy females in Korea. CA19-9 and CA125 were quantitated using solid-phase radioimmunoassay kits. Informations on the factors which might be related to the levels of these markers were collected by questionnaire(e.g., smoking, alcohol consumption, menstruation, oral pill use, breast-feeding history, etc.). There was no statistically significant difference in the mean of CA19-9 concentration between men(10.4 u/ml) and women(10.1 u/ml), whereas the mean of CA125 levels(11.2 u/ml) was higher in women than that(2.5 u/ml) in men. Although there was a statistically significant association between CA19-9 and average number of cigarette consumed per day(r=0.59, p=0.026) and total number of cigarettes consumed in women(r=0.74, p=0.003), the significance disappeared by multiple regression analysis after adjusting age and body mass index. Later age of menopause(p=0.035) and longer duration of breast-feeding(p=0.050) were significant predictors for CA125 levels in women by multiple regression analysis after adjusting age and body mass index. In conclusion, CA19-9 can be used as a stable tumor marker in clinical practices, however, menstruation and breast-feeding should be considered when CA125 is used in women.

• Radiation Oncology Journal
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• v.16 no.2
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• pp.99-106
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• 1998

Purpose : We conducted clonogenic assay using human cancer cell lines (MKN-45, PC-14, Y-79, HeLa) to investigate a correlation between the parameters of radiosensitivity. Materials and Methods : Human cancer cell lines were irradiated with single doses of 1, 2, 3, 5, 7 and 10Gy for the study of radiosensitivity and subrethal damage repair capacity was assessed with two fractions of 5Gy separated with a time interval of 0, 1, 2, 3, 4, 6 and 24 hours. Surviving fraction was assessed with clonogenic assay using $Sperman-H\"{a}rbor$ method and mathematical analysis of survival curves was done with linear-quadratic (LQ) , multitarget-single hit(MS) model and mean inactivation dose$(\v{D})$. Results : Surviving fractions at 2Gy(SF2) were variable among the cell lines, ranged from 0.174 to 0.85 The SF2 of Y-79 was lowest and that of PC-14 was highest(p<0.05, t-test). LQ model analysis showed that the values of $\alpha$ for Y-79, MKN-45, HeLa and PC-14 were 0.603, 0.356, 0.275 and 0.102 respectively, and those of $\beta$ were 0.005, 0.016, 0.025 and 0.027 respectively. Fitting to MS model showed that the values of Do for Y-79. MKN-45, HeLa and PC-14 were 1.59. 1.84. 1.88 and 2.52 respectively, and those of n were 0.97, 1.46, 1.52 and 1 69 respectively. The $\v{D}s$ calculated by Gauss-Laguerre method were 1.62, 2.37, 2,01 and 3.95 respectively So the SF2 was significantly correlated with $\alpha$, Do and $\v{D}$. Their Pearson correlation coefficiencics were -0.953 and 0,993. 0.999 respectively(p<0.05). Sublethal damage repair was saturated around 4 hours and recovery ratios (RR) at plateau phase ranged from 2 to 3.79. But RR was not correlated with SF2, ${\alpha}$, ${\beta}$, Do, $\v{D}$. Conclusion : The intrinsic radiosensitivity was very different among the tested human cell lines. Y-79 was the most sensitive and PC-l4 was the least sensitive. SF2 was well correlated with ${\alpha}$, Do, and $\v{D}$. RR was high for MKN-45 and HeLa but had nothing to do with radiosensitivity parameters. These basic parameters can be used as baseline data for various in vitro radiobiological experiments.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.137-147
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• 2014

Purpose : The purpose of this study is to verify the accuracy of dose delivery according to the patient's breathing cycle in Gated Volumetric Modulated Arc Therapy Materials and Methods : TrueBeam STxTM(Varian Medical System, Palo Alto, CA) was used in this experiment. The Computed tomography(CT) images that were acquired with RANDO Phantom(Alderson Research Laboratories Inc. Stamford. CT, USA), using Computerized treatment planning system(Eclipse 10.0, Varian, USA), were used to create VMAT plans using 10MV FFF with 1500 cGy/fx (case 1, 2, 3) and 220 cGy/fx(case 4, 5, 6) of doserate of 1200 MU/min. The regular respiratory period of 1.5, 2.5, 3.5 and 4.5 sec and the patients respiratory period of 2.2 and 3.5 sec were reproduced with the $QUASAR^{TM}$ Respiratory Motion Phantom(Modus Medical Devices Inc), and it was set up to deliver radiation at the phase mode between the ranges of 30 to 70%. The results were measured at respective respiratory conditions by a 2-Dimensional ion chamber array detector(I'mRT Matrixx, IBA Dosimetry, Germany) and a MultiCube Phantom(IBA Dosimetry, Germany), and the Gamma pass rate(3 mm, 3%) were compared by the IMRT analysis program(OmniPro I'mRT system software Version 1.7b, IBA Dosimetry, Germany) Results : The gamma pass rates of Case 1, 2, 3, 4, 5 and 6 were the results of 100.0, 97.6, 98.1, 96.3, 93.0, 94.8% at a regular respiratory period of 1.5 sec and 98.8, 99.5, 97.5, 99.5, 98.3, 99.6% at 2.5 sec, 99.6, 96.6, 97.5, 99.2, 97.8, 99.1% at 3.5 sec and 99.4, 96.3, 97.2, 99.0, 98.0, 99.3% at 4.5 sec, respectively. When a patient's respiration was reproduced, 97.7, 95.4, 96.2, 98.9, 96.2, 98.4% at average respiratory period of 2.2 sec, and 97.3, 97.5, 96.8, 100.0, 99.3, 99.8% at 3.5 sec, respectively. Conclusion : The experiment showed clinically reliable results of a Gamma pass rate of 95% or more when 2.5 sec or more of a regular breathing period and the patient's breathing were reproduced. While it showed the results of 93.0% and 94.8% at a regular breathing period of 1.5 sec of Case 5 and 6, it could be confirmed that the accurate dose delivery could be possible on the most respiratory conditions because based on the results of 100 patients's respiratory period analysis as no one sustained a respiration of 1.5 sec. But, pretreatment dose verification should be precede because we can't exclude the possibility of error occurrence due to extremely short respiratory period, also a training at the simulation and careful monitoring are necessary for a patient to maintain stable breathing. Consequently, more reliable and accurate treatments can be administered.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.895-905
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• 1994

The solid phase crystallization behavior of undoped amorphous $Si_{1-x}Ge_{x}$ (X=O to 0.53) alloyfilms was studied by X-ray diffractometry(XRD) and transmission electron microscopy(TEM). Thefilms were deposited on thermally oxidized 5" (100) Si wafer by MBE(Mo1ecular Beam Epitaxy) at 300'C and annealed in the temperature range of $500^{\circ}C$ ~ $625^{\circ}C$. From XRD results, it was found that the thermal budget for full crystallization of the film is significantly reduced as the Ge concentration in thefilm is increased. In addition, the results also shows that pure amorphous Si film crystallizes with astrong (111) texture while the $Si_{1-x}Ge_{x}$ alloy film crystallzes with a (311) texture suggesting that the solidphase crystallization mechanism is changed by the incorporation of Ge. TEM analysis of the crystallized filmshow that the grain morphology of the pure Si is an elliptical and/or a dendrite shape with high density ofcrystalline defects in the grains while that of the $Si_{0.47}Ge_{0.53}$ alloy is more or less equiaxed shape with muchlower density of defects. From these results, we conclude that the crystallization mechanism changes fromtwin-assisted growth mode to random growth mode as the Ge cocentration is increased.ocentration is increased.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.396-404
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• 2011

An investigation on the removals of PAH-quinone compounds, which are commonly produced from the biological and/or chemical treatments of PAH-contaminated soils, from the aqueous phase via birnessite (${\delta}-MnO_2$)-mediated oxidative transformation is described. It was demonstrated that acenaphthenequinone (APQ), p-PAH quinone can be removed via birnessite-mediated oxidative-coupling reactions, and anthraquinone (AQ) and 1,4-naphthoquinone (1,4-NPQ), o-PAH quinones were efficiently removed by birnessite-mediated cross-coupling reactions in the presence of catechol (CAT) as a reactive mediator. The removals of PAH-quinone compounds followed pseudo-first-order reactions, and the rate constant (k, $hr^{-1}$) for the removals of 1,4-NPQ under the experiment conditions (1,4-NPQ = 10 mg/L, CAT = 50 mg/L, ${\delta}-MnO_2$ = 1.0 g/L, pH 5, Reaction time = 6~96 hr) was 0.0426, which was about 4 times lower than that of APQ (0.173). With the observed pseudo-first order rate constants with respect to birnessite loadings under the same experimental conditions, the surface-normalized specific rate constant, $K_{surf}$, for 1,4-NPQ was determined to be $8.5{\times}10^{-4}L/m^2{\cdot}hr$. The analysis of the kinetic data with respect to birnessite loading indicated that the cross-coupling reactions of 1,4-NPQ consist of two different reaction steps over time and the results have also been discussed in terms of the reaction mechanisms.