• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.349-356
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• 2018

In this study, material properties of steel fiber reinforced high strength concrete (FRHSC) with the compressive strength of about 120MPa were modeled. Steel fiber content of 1.0%, 1.5%, and 2.0% was considered as experimental variable. First of all, compressive strength tests were carried out to determine compressive characteristics of concrete, and compressive stress-strain curves were modeled. For conventional concrete with moderate compressive strength, the stress-strain curves are in the form of parabolic curves, but in the case of high strength concrete reinforced with steel fiber, the curves increase linearly in the form of the straight line. In addition, to understand the tensile properties of FRHSC, the crack mouth opening displacement (CMOD) test was performed, and the tensile stress-CMOD curve was calculated through inverse analysis. When the steel fiber content increased from 1.0% to 1.5%, there was a significant difference of tensile strength. However, when the amount of steel fiber was increased from 1.5% to 2.0%, there was no significant difference of tensile strength, which might result from the poor dispersion and arrangement of steel fiber in concrete.

• Korean Journal of Metals and Materials
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• v.46 no.6
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• pp.351-356
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• 2008

Thermally sprayed tungsten carbide-based powder coatings are being widely used for a variety of wear resistance applications. The coating deposited by high velocity processes such as high velocity oxy-fuel (HVOF) thermal spraying is known to provide improved wear resistant property. In this study, optimal coating process (OCP) is obtained by the study of coating properties such as surface hardness, porosity, surface roughness and microstructure of 9 coatings prepared by Taguchi program for 3 levels of four spray parameters. The Friction and wear behaviors of HVOF WC-CoCr coating prepared by OCP, electrolytic hard chrome (EHC) plating and Inconel718 (In718) are investigated by reciprocating sliding wear test at $25^{\circ}C$, $450^{\circ}C$. Friction coefficients (FC) of all of the 3 samples are decreased as increasing sliding surface temperature from $25^{\circ}C$ to $450^{\circ}C$. FC of WC-CoCr decreases as increasing the surface temperature from $0.33{\pm}0.02$ at $25^{\circ}C$ to $0.26{\pm}0.02$ at $450^{\circ}C$, showing the lowest FC among the 3 samples. Wear trace (WT) and wear depth (WD) of WC-CoCr are smaller than those of EHC and In718 both at $25^{\circ}C$ and $450^{\circ}C$. These show that WC-CoCr is highly recommendable for protective coating on In718 and other metal components.

• Journal of the Korea Convergence Society
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• v.12 no.2
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• pp.347-356
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• 2021

The purpose of this study was to investigate the correlation between menopausal symptoms, perceived awareness of menopausal symptom, menopausal attitude and of menopausal management in middle aged women and to identify factors affecting menopausal symptoms. The subjects of study were 242 middle aged women who are living in G, J, K city and understood the research items and agreed to participate in the research. Data were collected from April 10 to May 30, 2019. Data were analyzed using t-test, ANOVA, Pearson's Correlation Coefficient and Stepwise Multiple Regression with SPSS/WIN 25.0. In this study, it was founded that perceived awareness of menopausal symptom(β=. 51, p<.001), menstruation status(β=. 23, p<.001), perceived health status(β=. 19, p=. 002), satisfaction of life(β=. 14, p=. 019) and religion(β=. 10, p=. 045) were found to be influential factors affecting menopausal symptoms in middle aged women. The most influential factor was perceived awareness of menopausal symptom. A nursing intervention program is needed to change positively the awareness of menopausal symptom.

• Korean Journal of School Psychology
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• v.17 no.3
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• pp.333-356
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• 2020

This study examined the mediating effects of fear of negative evaluation(FNE), fear of positive evaluation(FPE) and disqualification of positive social outcomes(DPSO) on the relationship between public self-consciousness(PSC) and social anxiety(SA) among college students. In this study, SA was divided into social interaction anxiety(SIA) and performance anxiety(PA). Participants included 316 undergraduates who completed a survey. There were three major results. First, PSC, SIA, PA, FNE, FPE and DPSO were positively correlated with each other. Second, FNE, FPE and DPSO had significant mediating effects on the relationship between PSC and SA. Third, when FNE, FPE and DPSO mediated the relationship between PSC and SA, the effect on PA was significantly greater than the effect on SIA, and in the path mediated by FNE, the effect on SIA was greater than the effect on PA. This paper discusses the findings and implications of this study.

• Journal of the Korea Convergence Society
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• v.13 no.2
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• pp.349-356
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• 2022

This study aims to identify factors related to suicide within one year of schizophrenia diagnosis based on data from National Health Information Database. We obtained data of 102,540 patients diagnosed with schizophrenia between 2007 to 2010 from customized database, which was checked using the National Statistics Organization database and schizophrenia cohort was built. The number of suicide within one year of schizophrenia diagnosis was 615(0.60%), and the risk of suicide within one year was high among patients within age group of 25-34 and patients with medium-low to high economic status. The risk of suicide within one year among male patients was high within age group of 45-54 and patients with medium-low to high economic status. The risk of suicide within one year among female patients was high within patients with high economic status. Age and economic status need to be considered during suicide prevention intervention of schizophrenia patients diagnosed within one year and suicide related factors by sex need to be especially considered.

• Korean journal of applied entomology
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• v.61 no.2
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• pp.349-356
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• 2022

Fall armyworm, Spodoptera frugiperda, is a invasive migratory pest of native to the tropical and sub-tropical regions that has recently invaded Korea with damage to cornfield. The study was conducted to investigate the development periods of S. frugiperda on artificial diet at six different temperatures. The developmental period from eggs to adult at 18, 21, 24, 27, 30 and 32℃ was 79.8, 54.2, 34.3, 28.4, 24.6 and 24.0 days, respectivery and decreased with increasing temperature. The pupal periods of females were shorter than males. Most of the larvae developed through six instar, but the ratio of 7 or more instar increased at low temperatures. The relationship between the development rate and temperature was fitted with by linear regression analysis. The lower development threshold for egg and larva development was 12.9℃ and 11.3℃, respectively, 12.6℃ for pupae and 11.8℃ for egg-to-adult development. The effective accumulative temperature for the development of the respective life cycle stages were 37.0 DD for eggs, 286.3 DD for larvae, 132.2 DD for pupae and 456.8 DD egg-to-adult development.

• Journal of Life Science
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• v.33 no.4
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• pp.349-356
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• 2023

Gout, a chronic inflammatory arthritic disease, is characterized by hyperuricemia. Gout can be induced by an inflammatory response to monosodium urate (MSU) crystals mediated by pro-inflammatory cytokine release following activation of the NOD-like receptor protein 3 (NLRP3) inflammasome. Many sulfur-containing phytochemical compounds in garlic (Allium sativum L.) are considered active ingredients because of their potential pharmacological benefits for various diseases, but their efficacy in NLRP3 inflammasome activation-mediated gout has not been demonstrated. In this study, we investigated whether diallyl disulfide (DADS) and diallyl trisulfide (DATS), representative garlic-derived sulfur compounds, have an inhibitory effect on MSU-induced NLRP3 inflammasome activation. Our results showed that under non-cytotoxic conditions, DADS and DATS significantly blocked nitric oxide production and interleukin (IL)-1β release in response to MSU in lipopolysaccharide (LPS)-primed RAW 264.7 macrophages. DADS and DATS also attenuated enhanced expression of NLRP3 and its adapter protein, apoptosis-associated speck-like protein, which was associated with downregulation of and caspase-1 p20 and IL-1β expression, suggesting that MSU-induced LRP3 inflammasome activation was counteracted by DADS and DATS. Furthermore, DADS and DATS blocked oxidative stress, an upstream event for NLRP3 inflammasome activation, as evidenced by the fact that they scavenged reactive oxygen species (ROS) production. Taken together, our findings demonstrate that DADS and DATS suppressed NLRP3 inflammasome activation by inhibiting the ROS/NLRP3 pathway and that they have potential as treatments for NLRP3-dependent gouty arthritis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4B
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• pp.347-356
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• 2009

This study simulates the dam break situation by a probable maximum precipitation of Soyang-River Dam using HEC-HMS model and HEC-RAS model and compares the simulated results. The probable maximum precipitation was calculated using the flood event of the typhoon Rusa occurred in 2002 and using the mean areal precipitation of the Gangreung region and the moisture maximization method. The estimated probable maximum precipitations were compared for the duration of 6, 12, 18, and 24 hrs and were used as input data for the HEC-HMS model. Moreover, the inflow data calculated by HEC-HMS were utilized as ones for HEC-RAS, and then unsteady flow analysis was conducted. The two models were used for the dam break analysis with the same conditions and the peak flow estimated by HEC-HMS was larger than that of the HEC-RAS model. The applicability of two models was performed from the dam break analysis then we found that we could simulate more realistic peak flow by HEC-RAS than HEC-HMS. However, when we need more fast simulation results we could use HEC-HMS. Therefore, we may need the guidelines for the different utilizations with different purposes of two models. Furthermore, since the two models still include uncertainties, it is important to establish more detailed topographical factors and data reflecting actual rivers.

• Korean Journal of Environmental Agriculture
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• v.41 no.4
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• pp.355-364
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• 2022

BACKGROUND: Pre-harvest interval and decline pattern of thiamethoxam were determined in kiwifruit using liquid chromatography-tandem mass spectrometry (LCMS/MS). The study was carried out to propose import tolerance using OECD maximum residue limit (MRL) calculator for the export promotion of kiwifruit to Taiwan. METHODS AND RESULTS: The thiamethoxam residue in kiwifruit was determined by using the LC-TriQ-MS/MS with the analytical process to set up the import tolerance under greenhouse conditions for Taiwan. Excellent linearity was observed for all of the analytes with a determination coefficient (R²)≥0.99. The limit of quantification was determined to be 0.01 mg/kg for both thiamethoxam and clothianidin in kiwifruit. Linearity was determined from the co-efficient of determinants (R²) obtained from the seven-point calibration curve. The standard calibration curve showed as follows; 1) Site 1 (Gimje): y = 944,406X + 1,583 (R²=0.9995), 2) Site 2 (Goheung): y = 1,356,205X + 934 (R²=0.9983), and 3) Site 3 (Jangheung): y = 1,239,937X - 3,090 (R²=0.9908). The residue of thiamethoxam in the kiwifruit for three decline trials showed the range of 0.35 to 0.56 mg/kg in site 1 (Gimje), 0.24 to 0.55 mg/kg in site 2 (Goheung), and 0.28 to 0.42 mg/kg in site 3 (Jangheung), respectively. However, clothianidin was not detected in all of the treatments. The maximum residual amounts (decline) in the samples, sprayed according to the safe-use standard for thiamethoxam 10% WG in kiwifruit (30 days before harvest, 3 sprays every 7 days) were 0.56 mg/kg in site 1, 0.55 mg/kg in site 2, and 0.42 mg/kg in site 3, respectively. CONCLUSION(S): The import tolerance (IT) of thiamethoxam for kiwifruit may be proposed to be 0.9 mg/kg by using the OECD MRL calculator.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.36-36
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• 2023

천마(天麻, Gastrodia elata Blume)는 난초과(蘭草科, Orchidaceae)에 속하는 식물로 잎과 뿌리가 없어 탄소동화능력이 없으며, 뽕나무버섯균과 공생하는 기생식물이다. 천마는 노지 재배에 따른 안정생산 문제가 지속적으로 발생하고 있다. 혹한, 폭우 등 기상환경에 따른 연차간 수량성 차가 673~1,175kg/10a로 크고, 연작에 따른 수량성이 연작 1회 시 29%, 연작 2회 시 68%가 감소하는 경향을 보이고 있다. 따라서, 본 연구는 천마의 연작에 따른 토양내 미생물상의 변화를 분석하기 위해 수행하였다. 본 실험은 초작지, 연작 1회지, 연작 2회지 및 자생지의 각각 3곳에 대한 토양을 Metagenome 분석법을 활용하여 미생물상을 분석하였다. metagenome 분석 결과, 초작지 3곳의 시료를 이용하여 확보한 총 read는 699,221개였으며, 이 중에서 Eukaryota로 분류되지 않은 read는 1,377개(0.2%), no hit, not assign된 read는 10,510개 (1.5%), Bacteria로 분류된 read는 342,916개(49.0%), Eukaryota로 분류된 read는 총 344,418개(49.3%)였다. 그리고 천마의 생육에 영향을 주는 Fusarium 속과 종은 3곳 포장에서 고르게 분포하고 있으며, 총 11,242 read로 전체의 3.3%를 차지하였다. 연작 1회지 3곳의 시료를 이용하여 확보한 총 read는 655,097개였으며, 이 중에서 Eukaryota로 분류되지 않은 read는 1,694개(0.3%), no hit, not assign된 read는 18,985개(2.9%), Bacteria로 분류된 read는 312,201개(47.7%), Eukaryota로 분류된 read는 총 322,217개 (49.2%)였다. 그리고 천마의 생육에 영향을 주는 Fusarium 속과 종은 3곳 포장에서 고르게 분포하고 있으며, 총 11,597 read로 전체의 3.6%를 차지하였다. 연작 2회지 3곳의 시료를 이용하여 확보한 총 read는 651,624개였으며, 이 중에서 Eukaryota로 분류되지 않은 read는 1,753개(0.3%), no hit, not assign된 read는 7,995개(1.2%), Bacteria로 분류된 read는 307,178개(47.1%), Eukaryota로 분류된 read는 총 334,698개(51.4%)였다. 그리고 천마의 생육에 영향을 주는 Fusarium 속과 종은 총 43,877 read로 전체의 13.1%를 차지하였다. 자생지 3곳의 시료를 이용하여 확보한 총 read는 731,719개였으며, 이 중에서 Eukaryota로 분류되지 않은 read는 2,828개(0.4%), no hit, not assign된 read는 585개(0.1%), Bacteria로 분류된 read는 356,690개(48.7%), Eukaryota로 분류된 read는 총 371,616개(50.8%)였다. 그리고 천마의 생육에 영향을 주는 Fusarium 속과 종은 MJH01 자생지에서만 전체의 0.2%(총 660 read)로 극히 일부가 분리되었다. 따라서, 천마의 생육에 영향을 미치는 Fusarium 속과 종은 초작지 3.3%, 연작 1회지 3.6%, 연작 2회지 13.1%, 자생지 0.2%로 나타났으며, 연작 2회 시 급격히 증가하는 것으로 판단되었다.