• The Journal of the Petrological Society of Korea
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• v.15 no.1 s.43
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• pp.25-38
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• 2006

Metamophic rocks of Samcheog area, northeastern Yeongnam massif, was studied petrochemically. This area includes Precambrian Hosanri Formation (schists and gneisses) and granitoid (Icheon granitic gneiss, leucocratic granite and Hongjesa granite), Cambrian sedimentary rocks, and Cretaceous sedimentary and acidic volcanic rocks. Hosanri formation is composed of quartz+plagioclase+K-feldspar+biotite+muscovite+granet${\pm}$cordierite${\pm}$sillimanite. Mineral assemblage of biotite granitic gneiss, which is massive granodioritic rock with weak foliation, is similar to Hosanri formation. According to mineral assemblages, metamorphic rocks of studied area can be divided into two metamorphic zones (garnet and sillimanite zones). From Icheonri area, major, trace and rare earth element data of biotite granitic gneiss and luecocratic granite suggest that source rock is politic rocks of Hosanri formation and source magma was formed by anatexis and experienced fractionation of plagioclase. Trace element diagram show collisional environment such as syn-collisional, volcanic arc granite. Orientation of faults in study area have three maximum concentrations, $N54^{\circ}\;W/77^{\circ}\;SW,\;N49^{\circ}\;W/81^{\circ}\;NE\;and\;N10^{\circ}\;W/38^{\circ}\;NE$. Structure analysis suggests that faults in study area ware formed by uplift and compression. Faulting age is guessed after Tertiary because some shear joints is developed in dikes to intrusive Cretaceous acidic volcanic rock. Hosanri formation and Icheon granitic gneiss had experienced similar deformation history because they have maximum concentration to foliations, $N89^{\circ}\;E/55^{\circ}\;SE\;and\;N80^{\circ}\;E/45^{\circ}\;SE$, respectively.

• The Journal of the Petrological Society of Korea
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• v.20 no.4
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• pp.173-189
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• 2011

Basic to acidic dykes and systematic joints are observed pervasively in the Jukbyeon-Bugu area, Uljin, east Korea. In order to classify the dykes and joints and to determine the relative chronology, their geometries, kinematics, and cross-cutting relationships, and the petrography and geochemistry of dykes are synthetically analyzed. Based on the orientations and cross-cutting relationships of 144 dykes (137 basic and 7 acidic dykes) and 370 systematic joints, three basic dike swarms (M-10, M-80, and M-100), one acidic dyke group (AD), and four joint sets (J-10, J-40, J-80, and J-150) are classified. Some of the J-150 joints reactivated as dextral strike-slip fault are recognized in the field and named as F-340R. According to petrographic, geochemical, and occurrence features in the field, M-80 and M-100 dykes have originated from a co-magma and intruded under the same stress field, even though they have intruded through different passages, preexisting fractures and new fractures created by magmatic pressure, respectively. And the relative chronology of dyke swarms and joint sets in the study area is determined as follows : ${\rightarrow}$ ${\rightarrow}$ ${\rightarrow}$ ${\rightarrow}$ ${\rightarrow}$ . And the M-80 (M-100) and M-10 dyke swarms intruded under NNE-SSW and NW-SE trending horizontal minimum stress fields, respectively. According to a synthesis of the results of the previous and this studies, the M-80, M-10, and F-340R are interpreted to have been formed about 64-52 Ma, Eocene~Oligocene, and Miocene, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.138-147
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• 2007

An emergy concept was used to evaluate the environment and economy of the Han River basin in Korea and to suggest policy perspectives far the sustainable utilization of its environment and associated estuarine ecosystem. The economy of the basin used $5.19{\times}10^{23}\;sej/yr$ of emergy in 2005. The economy of the Han River basin was heavily dependent on outside energy sources from foreign countries and other parts of Korea, with internal sources, renewable and nonrenewable, contributing only 15.6% to the total emergy use. The basin's trade balance in terms of emergy showed trade surplus, whereas there was a deficit in monetary terms. The population of the Han River basin was far greater than the carrying capacity calculated using the emergy flow, with renewable carrying capacity only at 1.8% of the basin's population and developed carrying capacity at 14.3%. The economy of the basin imposed a substantial stress on its environment, with an environmental loading ratio of 54.8. Overall, the economy of the Han River basin was not sustainable with an emergy sustainability of 0.02. These are reflected in lower quality of living expressed in the emergy term than the national average. Deconcentration of population and economic activities is needed to reduce environmental stress on the environment of the basin and its valuable estuarine ecosystem. Policies to restore ecosystem productivity of the basin are also needed to ensure the sustainability of the basin's economic activities and the sustainable utilization of the Han River estuary. In this regard, it is urgently needed for the Korean government to implement sustainable management measures for the Han River estuary, a well-preserved, productive natural estuarine ecosystem in Korea.

• The Journal of the Petrological Society of Korea
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• v.13 no.4
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• pp.179-190
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• 2004

Precambrian metamorphic rocks of Yeongyang-Uljin area, which is located in the eastern part of Sobaegsan Massif, Korea, are composed of Pyeonghae, Giseong, Wonnam Formations and Hada leuco granite gneisses. These show a zonal distribution of WNW-ESE trend, and are intruded by Mesozoic igneous rocks and are unconformably overlain by Mesozoic sedimentary rocks. This study clarifies the deformation history of Precambrian metamorphic rocks after the formation of gneissosity or schistosity on the basis of the geometric and kinematic features and the forming sequence of multi-deformed rock structures, and suggests that the geological structures of this area experienced at least four phases of deformation i.e. ductile shear deformation, one deformation before that, at least two deformations after that. (1) The first phase of deformation formed regional foliations and WNW-trending isoclinal folds with subhorizontal axes and steep axial planes dipping to the north. (2) The second phase of deformation occurred by dextral ductile shear deformation of top-to-the east movement, forming stretching lineations of E-W trend, S-C mylonitic structure foliations, and Z-shaped asymmetric folds. (3) The third phase deformation formed I-W trending open- or kink-type recumbent folds with subhorizontal axes and gently dipping axial planes. (4) The fourth phase deformation took place under compression of NNW-SSE direction, forming ENE-WSW trending symmetric open upright folds and asymmetric conjugate kink folds with subhorizontal axes, and conjugate faults thrusting to the both NNW and SSE with drag folds related to it. These four phases of deformation are closely connected with the orientation of regional foliation in the Yeongyang-Uljin area. 1st deformation produced regional foliation striking WNW and steeply dipping to the north, 2nd deformation locally change the strike of regional foliation into N-S direction, and 3rd and 4th deformations locally change dip-angle and dip-direction of regional foliation.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.345-351
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• 1996

Studies on extraction and color characteristics of purple sweet potato (PSP) pigment were performed to provide the basic information for the utilization of PSP as a new source of natural food colorant. PSP pigment was extracted well with the polar solvents such as distilled water, ethanol, and methanol. but hardly extracted with the non-polar solvents. Among the tested solvents, 20% ethanol solution containing 0.1% citric acid was found to be the most efficient for extraction of the pigment from PSP. PSP contained high amount of pigment not only in the epidermis but also in the flesh of the potato. The PSP pigment was heat stable even under pretreatments such as autoclaving and blanching of the potato before extraction. The optimum temperature of the extraction for the PSP Pigment was decided to be $30^{\circ}C$ by considering the stability and the rate of extraction. The pigment was markedly influenced by the change of pH. The color of the pigment solution was red at the pH range of $1.0{\sim}3.0$, became blue at $7.0{\sim}8.0$, then turned green at $9.0{\sim}10.0$. A characteristic batho-chromic shift of the pigment solution was observed as the pH of the solution increased.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.329-337
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• 2001

배경: 승포판 전엽이나 교련 또는 여러 판엽에 걸쳐 광범위한 병변으로 인한 승모판 역류의 경우 수술수기에 대한 뚜렷한 정립이 되어 있지 않은 실정이다. 최근 이러한 병변의 승모판 역류의 경우 PTEE(Polytetrafluro-ethylene)을 이용한 신건삭 형성술의 시행이 점차 늘고 있다. 이에 저자들은 PTEE를 이용한 신건삭 형성술이 승모판 성형술에 어떠한 영향을 미치는지 알아보고자 하였다. 대상 및 방법: 1994년 1월부터 1999년 12월까지 승모판막 성형술을 시행 받은 322명의 환자 중에서 신건삭 형성술을 이용하여 승모판 성형술을 시행한 144례(I군)과 신건삭 형성술 이외의 방법으로 승모판 성형술을 시행한 178례(II군)를 대상으로 하였다. 두 군에서 수술 직후ㅘ 수술 후 6개월, 1년 및 1년 단위로 주기적인 심초음파를 시행하였고 이를 통계적 검정하였다. 결과: 같은 기간 승모판 성형술은 승모판막 폐쇄 부전증으로 내원한 환자의 95%(306)에서 추적 관찰이 가능하였다. 두 구난에 수술 전 혈류 역학적인 차이를 보이지 않았고, 수술 전 평균 승모판막 폐쇄 부전의 정도는 I군이 3.8$\pm$0.4, II군이 3.6$\pm$0.3였으나 수술 후 추적 관찰에서 각각 1.3$\pm$0.9와 1.1$\pm$0.7 정도의 양호한 판막 성형술의 결과를 보였고 승모판막 면적의변화나 승모판막에서의 평균 압력차이 등 혈류 역학적인 결과에도 차이를 보이고 있지 않았다. 술 후 3명(0.9%)의 조기 사망과 4명 (1.2%)의 후기 사망이 있었으나 두 군간의 차이는 보이지 않았다. 만기 생존율( 93.7$\pm$3.3 vs 88.0$\pm$1.95) 및 판막살패가 발생하기 않을 확률( 93.7$\pm$3.6 vs 93.3$\pm$3.4%) 과 재수술이 필요치 않을 활률(99.3$\pm$0.7 vs 96.0$\pm$1.9%), 색전증, 감염성 심내막염, 판막과 관련된 합병증 발생률 등에서 두 군간에 의미 있는 차이는 없었다. 전엽과 후엽에서 신건삭 형성술을 시행한 환자에서는 통계학적인 차이가 없었다(p=0.29) 결론: 신건삭 형성술을 이용한 승모판 성형술은 승모판 성형술의 증가(r=0.98, p<0.01)를 가져 왔을 뿐만 아니라 내구성과 안정성에 있어 기존의 안전화된 수술 수기와 견줄만하다. 특히 이러한 신건삭 형성술은 승모판 전엽에 병변이 있는 경우와 교련부 및 여러 엽에 광범위한 병변으로 인하여 재건술이 어려운 경우에도 승모판 재건을 가능하게 하는 우수한 수술 수리가 사료된다.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.670-691
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• 2018

This study presents the research results of the BMT(Benchmark Model Test) simulations of the DECOVALEX-2019 project Task B. Task B named 'Fault slip modelling' is aiming at developing a numerical method to predict fault reactivation and the coupled hydro-mechanical behavior of fault. BMT scenario simulations of Task B were conducted to improve each numerical model of participating group by demonstrating the feasibility of reproducing the fault behavior induced by water injection. The BMT simulations consist of seven different conditions depending on injection pressure, fault properties and the hydro-mechanical coupling relations. TOUGH-FLAC simulator was used to reproduce the coupled hydro-mechanical process of fault slip. A coupling module to update the changes in hydrological properties and geometric features of the numerical mesh in the present study. We made modifications to the numerical model developed in Task B Step 1 to consider the changes in compressibility, Permeability and geometric features with hydraulic aperture of fault due to mechanical deformation. The effects of the storativity and transmissivity of the fault on the hydro-mechanical behavior such as the pressure distribution, injection rate, displacement and stress of the fault were examined, and the results of the previous step 1 simulation were updated using the modified numerical model. The simulation results indicate that the developed model can provide a reasonable prediction of the hydro-mechanical behavior related to fault reactivation. The numerical model will be enhanced by continuing interaction and collaboration with other research teams of DECOVALEX-2019 Task B and validated using the field experiment data in a further study.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.191-197
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• 2019

Although auto-adjusting positive airway pressure (APAP) titration at home has several advantages over a CPAP titration in terms of convenience and time saving, there are still concerns as to whether it will show corresponding accuracy when compared to laboratory-based polysomnography (PSG) and CPAP titration. To obtain more evidence supporting home-based auto-titration, APAP titration was performed at home for patients who were presented with OSA on laboratory-based diagnostic PSG followed by CPAP titration. A total of 79 patients were included in the study. They all underwent split-night PSG with CPAP titration, and APAP titration for more than 7 days. The patients with successful titration at both situations were selected. The optimal pressure and apnea-hypopnea index (AHI) of CPAP and APAP titration were compared. The optimal pressure for CPAP and APAP titration were $7.0{\pm}1.8cmH_2O$ and $7.6{\pm}1.6cmH_2O$ (P<0.001), whereas the corresponding AHI were $1.3{\pm}1.5/h$ and $3.0{\pm}1.7/h$ (P<0.001). As a result, the achievement rates of optimal pressure for CPAP and APAP titration were 96.2% and 94.9% (r=-0.045, P=0.688), respectively. The results of this study did not differ with regard to the optimal pressure between CPAP and APAP titration. Overall, CPAP and APAP titrations should be chosen depending on a required situation.

• Journal of the Korean Geotechnical Society
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• v.37 no.3
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• pp.19-30
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• 2021

The presence of the hydrate-bearing sediments in Ulleung Basin of South Korea has been confirmed from previous studies. Researches on gas production methods from the hydrate-bearing sediments have been conducted worldwide. As production mechanism is a complex phenomenon in which thermal, hydraulic, and mechanical phenomena occur simultaneously, it is difficult to accurately conduct the productivity and stability analysis of hydrate bearing sediments through lab-scale experiments. Thus, the importance of numerical analysis in evaluating gas productivity and stability of hydrate-bearing sediments has been emphasized. In this study, the numerical parametric analysis was conducted to investigate the effects of the bottom hole pressure and the depressurization rate on the gas productivity and stability of hydrate-bearing sediments during the depressurization method. The numerical analysis results confirmed that as the bottom hole pressure decreases, the productivity increases and the stability of sediments deteriorates. Meanwhile, it was shown that the depressurization rate did not largely affect the productivity and stability of the hydrate-bearing sediments. In addition, sensitivity analysis for gas productivity and stability of the sediments were conducted according to the depressurization rate in order to establish a production strategy that prevents sand production during gas production. As a result of the analysis, it was confirmed that controlling the depressurization rate from a low value to a high value is effective in securing the stability. Moreover, during gas production, the subsidence of sediments occurred near the production well, and ground heave occurred at the bottom of the production well due to the pressure gradient. From these results, it was concluded that both the productivity and stability analyses should be conducted in order to determine the bottom hole pressure when producing gas using the depressurization method. Additionally, the stress analysis of the production well, which is induced by the vertical displacements of sediments, should be evaluated.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.201-223
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• 2022

Currently, species extinctions are increasing due to climate change and continued anthropogenic impact. We selected 300 species for conservation with emphasis on plants co-occurring in the Baekdudaegan area, which is a large ecological axis of Korea. We aimed to investigate the vegetation community and environmental characteristics of Zabelia tyaihyonii in the limestone habitat among the target plant species in the Baekdudaegan region to derive effective conservation strategies. In Danyang-gun, Yeongwol-gun, and Jecheon-si, we selected 36 investigation sites where Z. tyaihyonii was present. We investigated the vegetation, flora, soil and physical environment. We also found notable plants such as Thalictrum petaloideum, Sillaphyton podagraria, and Neillia uekii at the investigation sites. We classified forest vegetation community types into 4 vegetation units and 7 species group types. With canonical correspondence analysis (CCA) of the vegetation community and habitat factors, we determined the overall explanatory power to be 75.2%, and we classified the environmental characteristics of the habitat of Z. tyaihyonii into a grouping of three. Among these, we detected a relationship between the environmental factors elevation, slope, organic matter, rock ratio, pH, potassium, and sodium. We identified numerous rare and endemic plants, including Thalictrum petaloideum, in the investigation site, and determined that these groups needed to be preserved at the habitat level. In the classification of the vegetation units analyzed based on the emerging plants and the CCA, we reaffirmed the uniqueness and specificity of the vegetation community in the habitat of Z. tyaihyonii. We anticipate that our results will be used as scientific evidence for the empirical conservation of the native habitats of Z. tyaihyonii.