• 한국광물학회:학술대회논문집
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• 한국광물학회.한국암석학회 2001년도 공동학술발표회 논문집
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• pp.95-95
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• 2001

The Yeongdong basin is one of the pull-apart basins in the southwestern part of the Korean Peninsula that has developed during Cretaceous sinistal fault movement. The bimodal igneous activities (basalts and rhyolites) in the basin appear to be closely associated with the basin development. Here, we discuss the origin of the igneous rocks using chemical and radiogenic isotope data. Basaltic (48.4-52.7 wt% SiO$_2$) and rhyolitic (70.3-70.8 wt% SiO$_2$) rocks are slightly alkalic in a total alkali-silica diagram. The rhyolitic rocks with have unusually high K$_2$O contents (5.2-6.0 wt%). The basaltic rocks show an overall pattern of within-plate basalt in a MORB-normalized spider diagram, but have distinct negative anomaly of Nb, which indicates a significant amount of crustal component in the magma. The basaltic rocks plot within the calc-alkaline basalt field in the Hf/3-Th-Ta and Y/l5-La/10-Nb/8 discrimination diagrams. The eNd(T) values of the basaltic rocks (-13.6 to 14.3) are slightly higher than those of the rhyolitic rocks (-14.1 to 15.2), and the initial Sr isotopic ratios of the former (0.7085-0.7093) are much lower than those of the latter (0.7140-0.7149). However, the initial Nd and Sr isotope ratios of the igneous rocks in the Yeongdong basin are similar to those of the nearby Cretaceous igneous rocks in the Okcheon belt. The Pb isotope ratios plot within the field of Mesozoic granitoids outside of the Gyeongsang basin in Pb-Pb correlation diagrams. Since a basaltic magma requires the mantle source, the enriched isotopic signatures and negative Nb anomaly of the basaltic rocks suggest two possibilities for their origin: enriched mantle lithospheric source, or depleted mantle source with significant amount of crustal contamination. However, we prefer the first possibility since it would be difficult for a basaltic magma to maintain its bulk composition when it is significantly contaminated with granitic crustal material. The slightly more enriched isotopic signatures of rhyolitic rocks also suggest two possibilities: differentiate of the basaltlc magma with some crustal contamination, or direct partial melting of the lower crust. Much larger exposed volume of the rhyolitic rocks, compared with the basaltic rocks, indicates the latter possibility more favorable.

• 한국재난정보학회 논문집
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• 제19권1호
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• pp.161-172
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• 2023

건설근로자에게 강의식으로 전달하는 안전교육은 집중도와 몰입도에 한계가 있으므로 전달력과 흥미가 떨어진다. 교육을 통하여 불안전한 행동을 개선하고, 안전사고를 예방하기 위해서는 체험식 교육으로 패러다임을 전환할 필요가 있다. 연구목적: 체험식 안전교육은 건설근로자가 위험을 더 빠르게 인지하고, 응급대처 능력향상과 사전·사후 학습전이 효과성을 검증하므로 건설근로자 사고 예방에 기여하고, 체험교육이 건설근로자 안전한 행동 유도에 미치는 영향 연구가 목적이다. 연구방법:실제 건설 현장과 동일 작업환경으로 구성된 체험시설을 경험한 종사자들의 설문으로 안전체험교육 사전·사후에 대한 의견조사와 학습전이 성과에 대해서 조작적 정의와 변수측정도구를 계획하고, 연구가설을 설정하였다. 연구결과: 구조방정식 모형을 통하여 경로분석 하였으며, 베이지안 이론과 MC 시뮬레이션 분석법으로 척도목표 기술통계량 및 척도입력 기술통계량에서 의도된 안전(A), 불안전(B)의 하위영역 비(非) 체험 교육, 체험식 교육의 평균, 표준편차, 최소·최대 값을 통해서 건설근로자 행동 변화를 확인하고 가설을 증명하였다. 결론: 건설근로자들에게 참여동기가 유발되어야 교육의 효과와 산업재해가 감소된다.

• 한국작물학회지
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• 제42권2호
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• pp.228-235
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• 1997

알팔파 종자와 재배지 토양의 추출물이 알팔파 및 무우의 발아 및 생육에 미치는 영향과 이들 물질을 구명코자 수행한 결과를 요약하면 다음과 같다. 1) 알팔파 종자 추출물의 무우생육에는 Luna, Sparta, Magnum, Husky, Milkmaker, Challenger, Anchor의 7개 품종에서 60∼80％ 생육억제 효과를 보였다. 2) 알팔파 재배지 토양잔류추출물을 이용한 무우생육조사는 추출물의 농도가 증가하면서 발아억제 및 줄기, 뿌리 등의 생장억제에 관여하는 것으로 나타났다. 3) 알팔파 재배토양으로 알팔파와 무우 생육실험시에는 80％의 발아억제를 보이면서 줄기와 뿌리의 길이 및 생체중에서도 큰 차이를 보여 allelopathy와 autotoxicity가 관여하는 것으로 사료된다. 4) 위 실험을 통해 관여하는 물질의 활성을 분석하기 위해 조사한 결과 표준 phenol compounds와 식물부위별 추출물을 비교 분석하였더니 salicylic acid, p-hydroxybenzoic acid, vanillic acid, syringic acid, p-cou-maric acid, ferulic acid 등의 7가지 acids를 분리동정 할 수 있었다.

• Computers and Concrete
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• 제31권4호
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• pp.337-348
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• 2023

Shear wall is commonly used as a lateral force resisting system of concrete mid-rise and high-rise buildings, but it brings challenges in providing relatively large space throughout the building height. For this reason, the structure system where the upper structure with bearing, non-bearing and/or shear walls that sits on top of a transfer plate system supported by widely spaced columns at the lower stories is preferred in some regions, particularly in low to moderate seismic regions in Asia. A thick reinforced concrete (RC) plate has often been used as a transfer system, along with RC transfer girders; however, the RC plate becomes very thick for tall buildings. Applying the post-tensioning (PT) technique to RC plates can effectively reduce the thickness and reinforcement as an economical design method. Currently, a simplified model is used for numerical modeling of PT transfer plate, which does not consider the interaction of the plate and the upper structure. To observe the actual behavior of PT transfer plate under seismic loads, it is necessary to model whole parts of the structure and tendons to precisely include the interaction and the secondary effect of PT tendons in the results. This research evaluated the seismic behavior of shear wall-type residential buildings with PT transfer plates for the condition that PT tendons are included or excluded in the modeling. Three-dimensional finite element models were developed, which includes prestressing tendon elements, and response spectrum analyses were carried out to evaluate seismic forces. Two buildings with flat-shape and L-shape plans were considered, and design forces of shear walls and transfer columns for a system with and without PT tendons were compared. The results showed that, in some cases, excluding PT tendons from the model leads to an unrealistic estimation of the demands for shear walls sit on transfer plate and transfer columns due to excluding the secondary effect of PT tendons. Based on the results, generally, the secondary effect reduces shear force demand and axial-flexural demands of transfer columns but increases the shear force demand of shear walls. The results of this study suggested that, in addition to the effect of PT on the resistance of transfer plate, it is necessary to include PT tendons in the modeling to consider its effect on force demand.

• 한국조경학회지
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• 제51권4호
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• pp.16-30
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• 2023

메타버스의 개념이 주목받게 됨에 따라 조경 분야에서 메타버스 활용에 대한 관심도 커졌다. 본 연구의 목적은 메타버스 플랫폼의 조경 가상공간의 이용자 경험을 분석하여 메타버스의 조경적 활용 가능성과 과제를 밝히는 데 있다. 본 연구는 현재 가상현실로 구현된 국내의 조경 공간 중 가장 이용도가 높은 로불록스 기반으로 만들어진 메타-에버랜드를 대상으로 메타버스의 연구를 진행하였다. 에버랜드 이용 경험이 있는 30명을 대상으로 메타-에버랜드 체험 후 실제 에버랜드를 추천할 의향이 있는지를 NPS 지수로 평가하여 메타버스의 효용성을 평가한 후 인터뷰를 진행하였다. 메타버스 체험 전의 NPS는 -16이었고 체험 후는 -24로 나타나 오히려 메타버스 체험 후 실제 공간에 대한 추천 의사는 더 낮아진 것으로 나타났다. 추천 의사가 낮아진 이유는 이용자의 부족, 낮은 그래픽 수준과 조작성, 콘텐츠의 부족으로 분석되었다. 이 중 이용자 부족은 다른 두 문제 원인의 결과로 볼 수 있으며 낮은 그래픽 수준과 조작성은 기술적인 문제로 단기간의 구조적 해결은 어렵다. 따라서 현실적으로 조경 공간 메타버스의 활용성을 높이기 위해서는 메타버스 콘텐츠에 대한 개발이 중심적 과제로 판단되었다. 메타버스의 콘텐츠는 현실과의 정합성을 높이기보다 현실과 연계된 메타버스 고유 콘텐츠의 개발이 더 바람직하다고 판단되었으며 AR, VR 기기의 결합, SNS적 성격의 소통 기능 강화, 시뮬레이션 검증 장치로서의 가능성을 고려할 필요가 있었다.

• 한국재난정보학회 논문집
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• 제19권3호
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• pp.519-531
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• 2023

건설 사업장에서 발생하는 안전사고 예방을 목표로 건설 현장의 불안전한 행동이라는 고질적 어려움과 고충을 해소하기 위해서 스마트 안전보건활동이라는 변수를 통하여 의도된 안전한 행동을 만들고, 이러한 행동 변화로 산업재해 감소에 도움이 되고자 한다. 연구목적: 스마트 안전보건활동이 불안전한 행동으로 발생하는 사고와 근본 원인인 근로자 행동 변화에 어떤 영향을 미치는지 분석하고, 이 활동은 근로자의 안전 경험치가 향상되고, 불안전한 행동을 의도된 안전한 행동으로 변화되며, 작업중에 나타나는 불안전 행동이 줄어들므로 안전사고 예방과 근로자 생명 보호에 도움이 된다는 가설을 검증한다. 연구방법: 스마트 안전보건활동을 독립변수(X)로 선정하였고, 근로자 행동 의도인 의도된 안전과 불안전을 종속변수(Y), 태도와 주관적 규범, 계획된 행동 통제를 매개변수(M)로 정하였다. 척도의 신뢰성과 타당도 분석은 안전보건활동에 관한 탐색적 요인분석과 판별타당도분석, 집중타당도를 분석했으며, 행동 변화의 가설검증을 위해서 주요 변수의 경로분석과 근로자 행동 변화의 실증분석으로는 베이지안모델 분석과 MC시뮬레이션의 확률밀도 분포를 통해 연구를 검증했다. 연구결과:건설 현장의 스마트 안전보건활동을 경험한 근로자는 불안전한 행동이 줄고, 의도된 안전 행동을 한다는 분석이 가장 높게 나타남을 알 수 있었다. 이는 근로자 행동변화에 영향을 미칠것이라는 연구가설이 입증되었고, 연구분석의 구조방정식과 경로분석에서 변수간의 상관관계 확인, 실증분석을 통해 스마트 안전보건활동이 근로자 불안전한 행동을 통제하고, 감소시킬 수 있다는 점을 확인하였다. 결론:건설 현장에서 사고를 예방하고 근로자의 행동을 변화시키기 위해서는 스마트 안전 보건활동이 매우 중요한 항목이란 것을 알 수 있었다.

• 현장농수산연구지
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• 제12권1호
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• pp.137-150
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• 2010

1. Lwang은 해발 1,200m 정도의 산악지역으로 일교차가 크고 햇볕의 양이 많은 지역으로 토양산도는 차재배에 이상적인 pH(H₂O)가 평균 5.60이다. 2. pH(KCL) 4.26으로 이상적이다. 그러나 두 pH 차이가 1.34으로 심한 양분 부족 현상을 보이며 토양 EC가 0.05 mS/cm로 심각한 토양 수탈현상을 보이고 있다. 3. 토양의 산화환원전위(ORP)는 393mV로 아주 이상적인 토양을 보이고 있다. 토양산도와 함께 산화환원전위(ORP)는 좋은 유기농 차를 만드는데 큰 역할을 하고 있다. 4. 차는 연중 양분(養分)을 흡수하고 있는데, 측정 결과는 전 항목에서 심한 양분의 부족현상을 보여 향후 유기물의 투입이 요구되고 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.174-174
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• 2000

A strong antiferromagnetic coupling in Fe/Si multilayered films (MLF) had been recently discovered and much consideration has been given to whether the coupling in the Fe/Si MLF system has the same origin as the metal/metal MLF. Nevertheless, the nature of the interfacial ron silicide is still controversial. On one hand, a metal/ semiconductor structure was suggested with a narrow band-gap semiconducting $\varepsilon$-FeSi spacer that mediates the coupling. However, some features show that the nature of coupling can be well understood in terms of the conventional metal/metal multilayered system. It is well known that both magneto-optical (MO) and optical properties of a metal depend strongly on their electronic structure that is also correlated with the atomic and chemical ordering. In this study, the nature of the interfacial regions is the Fe/Si multilayers has been investigated by the experimental and computer-simulated MO and optical spectroscopies. The Fe/Si MLF were prepared by rf-sputtering onto glass substrates at room temperature with the number of repetition N=50. The thickness of Fe sublayer was fixed at 3.0nm while the Si sublayer thickness was varied from 1.0 to 2.0 nm. The topmost layer of all the Fe/Si MLF is Fe. In order to carry out the computer simulations, the information on the MO and optical parameters of the materials that may constitute a real multilayered structure should be known in advance. For this purpose, we also prepared Fe, Si, FeSi2 and FeSi samples. The structural characterization of Fe/Si MLF was performed by low- and high -angle x-ray diffraction with a Cu-K$\alpha$ radiation and by transmission electron microscopy. A bulk $\varepsilon$-FeSi was also investigated. The MO and optical properties were measured at room temperature in the 1.0-4.7 eV energy range. The theoretical simulations of MO and optical properties for the Fe/Si MLF were performed by solving exactly a multireflection problem using the scattering matrix approach assuming various stoichiometries of a nonmagnetic spacer separating the antiferromagnetically coupled Fe layers. The simulated spectra of a model structure of FeSi2 or $\varepsilon$-FeSi as the spacer turned out to fail in explaining the experimental spectra of the Fe/Si MLF in both intensity and shape. Thus, the decisive disagreement between experimental and simulated MO and optical properties ruled out the hypothesis of FeSi2 and $\varepsilon$-FeSi as the nonmagnetic spacer. By supposing the spontaneous formation of a metallic ζ-FeSi, a reasonable agreement between experimental and simulated MO and optical spectra was obtained.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.107-107
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• 1997

Cytochrome P450 enzymes have been intensively investigated in hepatic tissues and several mammalian cell lines. Compared to most studies about cytochrome P450 isozymes in liver in vivo and hepatic, cell lines in vitro, the study of cytochrome P450IA1 in human breast cancer cells could be very important to understand the mechanism of the regulation of CYPIA1 gene expression and cell growth. MCF-7 human breast cancer cells are well characterized to study estrogen and antiestrogen action due to the fact that they contain high level of estrogen receptor and have biological markers characterized. And also MCF-7 cells express high level of arylhydrocarbon hydroxylase activity and human cytochrome P450IA1 cDNA was cloned from MCF-7 cells. Ah receptor was characterized in many breast cancer cell lines and polycyclic aromatic hydrocarbon such as 3-MC induced the expression of CYPIA1 gene and cytochrome P450- dependent monooxygenase activity. We undertook a study to examine the effect of estrogens and other chemicals on the regulation of human CYPIA1 gene expression in MCF-7 cells via RTPCR analysis, that might help us to understand the mechanism of the regulation of CYPIA1 gene expression and MCF-7 cell growth. Expression vector containing the functional 5'-regulatory region of human CYPIA1 fused to the CAT reporter gene was transfected into estrogen receptor positive MCF-T cells or estrogen receptor negative MDA-MB-231 cells. After these cells were treated with various chemicals, RTPCR was carried out to measure both CYPIA1 mRNA and CAT mRNA levels. 1nM 3-MC increased in both P450 and CAT mRNA levels over those of control by two folds in MCF-7 cells but does not in MDA-MB-231 cells. Estrogen or tamoxifen or retinoic acid or chrysin decreased in both P450 and CAT mRNA levels that were induced by 3-MC in MCF-7 when each chemical was administered with 3-MC concomitantly. These results suggested that the level of CYPIA1 gene expression is modulated with estrogen-related molecules and make it possible to speculate that ER is related to CYPIA1 gene expression and cell growth in breast cancer cells. [Supported by grants from the Korean Ministry of Education ]

• 한국지진공학회논문집
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• 제27권1호
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• pp.25-35
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• 2023

Considering the non-linear behavior of structure and soil when evaluating a nuclear power plant's seismic safety under a beyond-design basis earthquake is essential. In order to obtain the nonlinear response of a nuclear power plant structure, a time-domain SSI analysis method that considers the nonlinearity of soil and structure and the nonlinear Soil-Structure Interaction (SSI) effect is necessary. The Boundary Reaction Method (BRM) is a time-domain SSI analysis method. The BRM can be applied effectively with a Perfectly Matched Layer (PML), which is an effective energy absorbing boundary condition. The BRM has a characteristic that the magnitude of the response in far-field soil increases as the boundary interface of the effective seismic load moves outward. In addition, the PML has poor absorption performance of low-frequency waves. For this reason, the accuracy of the low-frequency response may be degraded when analyzing the combination of the BRM and the PML. In this study, the accuracy of the analysis response was improved by adjusting the PML input parameters to improve this problem. The accuracy of the response was evaluated by using the analysis response using KIESSI-3D, a frequency domain SSI analysis program, as a reference solution. As a result of the analysis applying the optimal PML parameter, the average error rate of the acceleration response spectrum for 9 degrees of freedom of the structure was 3.40%, which was highly similar to the reference result. In addition, time-domain nonlinear SSI analysis was performed with the soil's nonlinearity to show this study's applicability. As a result of nonlinear SSI analysis, plastic deformation was concentrated in the soil around the foundation. The analysis results found that the analysis method combining BRM and PML can be effectively applied to the seismic response analysis of nuclear power plant structures.