• 한국전산구조공학회논문집
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• 제22권6호
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• pp.565-572
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• 2009

본 연구에서는 EGW공정 적용에 따른 고강도 극후판 EH36-TMCP강 용접부의 역학적 거동 및 파괴인성 $K_{IC}$ 특성을 고찰하기 위해 먼저 자체 개발한 열분포, 열탄소성 프로그램을 이용한 유한요소해석을 통하여 용접부의 역학적 거동(용접잔류응력, 소성변형율 등의 크기, 분포, 발생기구)을 규명하였다. 그리고 이때 얻어진 잔류응력을 초기응력으로 하여 상용프로그램 ANSYS에서 노치가공으로 인한 응력 재분포 특성 및 잔류응력과 외력의 복합하중에 대한 파괴인성 KIC를 계산하였다. 균열이 존재하는 EGW용접부의 파괴기준$K_{IC}$를 살펴보면, 중첩된 경우가 순수 외부하중(굽힘하중)만 작용하는 경우 보다 파괴 인성치가 다소 감소하는 경향을 보였다. a/W가 작을 경우 중첩의 경우가 순수 외부하중(굽힘하중)만의 경우보다 파괴인성치 차이가 크나, a/W가 증가함에 따라 그 차이가 점차 없어지는 것으로 나타났다.

• 한국농공학회논문집
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• 제62권6호
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• pp.11-20
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• 2020

We estimated the spatio-temporally distributed soil moisture using Sentinel-1A/B SAR (Synthetic Aperture Radar) sensor images and soil moisture data assimilation technique in South Korea. Soil moisture data assimilation technique can extract the hydraulic parameters of soils using observed soil moisture and GA (Genetic Algorithm). The SWAP (Soil Water Atmosphere Plant) model associated with a soil moisture assimilation technique simulates the soil moisture using the soil hydraulic parameters and meteorological data as input data. The soil moisture based on Sentinel-1A/B was validated and evaluated using the pearson correlation and RMSE (Root Mean Square Error) analysis between estimated soil moisture and TDR soil moisture. The soil moisture data assimilation technique derived the soil hydraulic parameters using Sentinel-1A/B based soil moisture images, ASOS (Automated Synoptic Observing System) weather data and TRMM (Tropical Rainfall Measuring Mission)/GPM (Global Precipitation Measurement) rainfall data. The derived soil hydrological parameters as the input data to SWAP were used to simulate the daily soil moisture values at the spatial domain from 2001 to 2018 using the TRMM/GPM satellite rainfall data. Overall, the simulated soil moisture estimates matched well with the TDR measurements and Sentinel-1A/B based soil moisture under various land surface conditions (bare soil, crop, forest, and urban).

• Journal of Welding and Joining
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• 제27권6호
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• pp.31-35
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• 2009

When conducting CTOD test, especially in thick welded steel plate, fatigue pre-cracking occasionally failed to satisfy the requirements of standards thus making the test result invalid. Internally accumulated residual stress of test piece has been thought as one of the main reasons. The propagation of fatigue crack, started from the tip of machined notch, which might have propagated irregularly due to residual stress field. To overcome this kind of difficulty three methods to modify the residual stress are suggested in standard i.e. local compression, reverse bending and stepwise high-R ratio method. In this paper not only multi pass welding but also local pre-compressing process of thick steel plate has been simulated using finite element method for clarifying variation of internal welding residual stress. The simulated results show that welding residual stress is compressive in the middle section of the model and it is predominantly increased after machining the specimen. Comparing as-welded state all component of the welding residual stress changing to compressive in the tip of machine notch whereas residual stress of the outer area remain as tensile condition relatively. Analysis results also show that this irregular residual stress distribution is improved to be more uniformly by applying local compression.

• Journal of Ginseng Research
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• 제46권3호
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• pp.435-443
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• 2022

Background: Post-traumatic stress disorder (PTSD) is a psychiatric disease that develops following exposure to a traumatic event and is a stress-associated mental disorder characterized by an imbalance of neuroinflammation. Korean Red Ginseng (KRG) is the herbal supplement that is known to be involved in a variety of pharmacological activities. We aimed to investigate the effects of KRG on neuroinflammation as a potential mechanism involved in single prolonged stress (SPS) that negatively influences memory formation and consolidation and leads to cognitive and spatial impairment by regulating BDNF signaling, synaptic proteins, and the activation of NF-κB. Methods: We analyzed the cognitive and spatial memory, and inflammatory cytokine levels during the SPS procedure. SPS model rats were injected intraperitoneally with 20, 50, or 100 mg/kg/day KRG for 14 days. Results: KRG administration significantly attenuated the cognitive and spatial memory deficits, as well as the inflammatory reaction in the hippocampus associated with activation of NF-κB in the hippocampus induced by SPS. Moreover, the effects of KRG were equivalent to those exerted by paroxetine. In addition, KRG improved the expression of BDNF mRNA and the synaptic protein PSD-95 in the hippocampus. Taken together, these findings demonstrate that KRG exerts memory-improving actions by regulating anti-inflammatory activities and the NF-κB and neurotrophic pathway. Conclusion: Our findings suggest that KRG is a potential functional ingredient for protecting against memory deficits in mental diseases, such as PTSD.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3409-3416
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• 2023

Licensing the next-generation of nuclear reactor designs requires extensive use of Modeling and Simulation (M&S) to investigate system response to many operational conditions, identify possible accidental scenarios and predict their evolution to undesirable consequences that are to be prevented or mitigated via the deployment of adequate safety barriers. Deep Learning (DL) and Artificial Intelligence (AI) can support M&S computationally by providing surrogates of the complex multi-physics high-fidelity models used for design. However, DL and AI are, generally, low-fidelity 'black-box' models that do not assure any structure based on physical laws and constraints, and may, thus, lack interpretability and accuracy of the results. This poses limitations on their credibility and doubts about their adoption for the safety assessment and licensing of novel reactor designs. In this regard, Physics Informed Neural Networks (PINNs) are receiving growing attention for their ability to integrate fundamental physics laws and domain knowledge in the neural networks, thus assuring credible generalization capabilities and credible predictions. This paper presents the use of PINNs as surrogate models for accidental scenarios simulation in Nuclear Power Plants (NPPs). A case study of a Loss of Heat Sink (LOHS) accidental scenario in a Nuclear Battery (NB), a unique class of transportable, plug-and-play microreactors, is considered. A PINN is developed and compared with a Deep Neural Network (DNN). The results show the advantages of PINNs in providing accurate solutions, avoiding overfitting, underfitting and intrinsically ensuring physics-consistent results.

• 대한조선학회논문집
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• 제38권1호
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• pp.99-107
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• 2001

어선 제작시 어선의 고속화 및 어로작업 등에 의한 내구성을 향상시키기 위해 선각재질이 가볍고, 강도, 화재 및 해수의 부식 등에 뛰어난 재료의 사용이 요구되어지고 있다. 이러한 어선으로서는 크게 FRP어선과 Al어선으로 대별할 수 있다. 그러나 FRP어선은 가볍고 강도는 우수하나 인화성이 높아서 열에 매우 약하고 선박 제작 과정에 있어 인체에 해로운 유해성분이 발생할 뿐만 아니라, 폐선의 경우 산업폐기물로써 환경 오염에 큰 영향을 미치고 있다. 그런 반면에, Al어선은 FRP어선의 단점을 보완할 수 있는 재료로써, 고강도 및 경량화의 효과를 낼 수 있고, FRP어선보다 인화성이 낮아서 열에 강하고, 내구성이 높아 해수의 부식방지에 뛰어나므로 Al 어선의 개발이 시급한 실정이다. 그러나, 알루미늄 합금은 용접성이 좋지 않고 용접변형 및 균열이 발생하고, 건조 비용이 비싸다는 단점이 있다. 따라서, 본 연구에서는 Al 합금 접합시의 문제점 해결방안으로 용접이음부의 새로운 형상을 개발하고 개발한 신형상에 대한 역학적 거동을 규명하고자 하였다. 이를 위해, 먼저 평판 이론을 이용하여 구조부재를 단순화하여 평판, 보강판, 신형상에 대하여 해석함으로써 강도를 비교 검토하고, 이러한 결과를 토대로 자체 개발된 용접열전도 및 용접열응력 수치해석 프로그램을 사용하여 평판과 신형상의 온도분포, 용접잔류응력, 인장, 압축시의 강도를 수치시뮬레이션을 통하여 비교, 검토하였다. 또한, 인장 시험편을 제작하여 실험을 통하여 강도를 비교함으로써 신형상에 대한 적용 가능성 및 역학적 우수성을 입증하고자 하였다.

• 한국연극학
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• 제40호
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• pp.239-275
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• 2010

Cette ${\acute{e}}tude$ a pour but de proposer une $m{\acute{e}}thodologie$ de critique avec la $s{\acute{e}}miotique$ ouverte. La critique de $th{\acute{e}}{\hat{a}}tre$ commence ${\grave{a}}$ lire le $th{\acute{e}}{\hat{a}}tre$, l'analyse et juge son valeur. Il arrive souvent qu'on juge avec intutition. On dit que c'est une critique d'impressionnisme. Cette critique est subjective, mais pas objective. La $s{\acute{e}}miotique$ de Saussure offre la $m{\acute{e}}thodologie$ scientifique ${\grave{a}}$ la critique. A $c{\hat{o}}t{\acute{e}}$ de la critique d'impressionnisme qui est subjective, la $s{\acute{e}}miotique$ peut expliciter la raison objective. On ${\acute{e}}tait$ admiratif devant sa scientisme, pourtant $apr{\grave{e}}s$ quoi on critique sa non-$subjectivit{\acute{e}}$ et sa non-$historicit{\acute{e}}$. Dans l'opposition de $l^{\prime}objectivit{\acute{e}}$ et de la $subjectivit{\acute{e}}$, on tente de rechercher un model $int{\acute{e}}gr{\acute{e}}$ dialectiquement entre l'impressionisme(subjective) et la scientisme(objective). Pour cela, on doit aux Ecrits de linguistique $g{\acute{e}}n{\acute{e}}rale$ ($publi{\acute{e}}$ en 2002 chez Gallimard). Ces Ecrits nous aident ${\grave{a}}$ amener la $s{\acute{e}}miotique$ $ferm{\acute{e}}e$ sur la $s{\acute{e}}miotique$ ouverte et ${\grave{a}}$ $red{\acute{e}}couvrir$ la $pens{\acute{e}}e$ de Saussure. Ils nous font ouvrir un nouveau champ de recherche pour la $s{\acute{e}}miotique$ ouverte. L'essentiel de la $th{\acute{e}}orie$ saussurienne du signe $d{\acute{e}}pend$ de l'arbitraire et du circulaire du signe. On $red{\acute{e}}couvre$ la notion ${\acute{e}}largie$ du signe, dans Ecrits de linguistique $g{\acute{e}}n{\acute{e}}rale$, contre le courant majeur de linguistique et de structuralisme. Cette notion s'y focalise, ${\grave{a}}$ la valeur, ${\grave{a}}$ la $relativit{\acute{e}}$, ${\grave{a}}$ la $diff{\acute{e}}rence$ et au $syst{\grave{e}}me$. Avec elle, on tente d'adopter la $s{\acute{e}}miotique$ ouverte pour rechercher une $m{\acute{e}}thodologie$ de critique qui se veut objective et ${\grave{a}}$ la fois subjective. Il s'agit d'une difficile combinaison de l'impressionisme et de la scienticisme. Pour cela, la $m{\acute{e}}thodologie$ se $d{\acute{e}}veloppera$ en trois ${\acute{e}}tapes$. $1{\grave{e}}re$ ${\acute{e}}tape$: c'est lire le $th{\acute{e}}{\hat{a}}tre$ comme un signe total pour 1er jugement d'impressionnisme. $2{\grave{e}}me$ ${\acute{e}}tape$: c'est retrouver sa structure invisible dans la $relativit{\acute{e}}$ des signes. $3{\grave{e}}me$ ${\acute{e}}tape$: c'est juger, dans leur $relativit{\acute{e}}$, comment les $d{\acute{e}}tails$ de signes se fonctionnent. C'est lire les $d{\acute{e}}tails$ de signes et puis $r{\acute{e}}affirmer$ le jugement en $1{\grave{e}}re$ ${\acute{e}}tape$. Selon les $derni{\grave{e}}res$ deux ${\acute{e}}tapes$, on pourra comparer le premier jugement (impressif) et le dernier jugement (objectif), et enfin s'assumer comme critique. Selon la $m{\acute{e}}thodologie$ $propos{\acute{e}}e$, on pratique la critique sur ${\acute{e}}crit$ par Jean Genet, et mise en $sc{\grave{e}}ne$ par Lee Youn-Taek et par Park Jung-Hee. Pour la critique intertextuelle, on la fera en comparant les deux spectacles avec la $pi{\grave{e}}ce$ de Jean Genet. $D^{\prime}apr{\grave{e}}s$ la comparaison, Lee Youn-Taek met en $sc{\grave{e}}ne$ avec $fid{\acute{e}}lit{\acute{e}}$ la structre et les signes de $d{\acute{e}}tail$ de l'auteur, Park Jung-Hee change sa structre et ses signes pour mettre en $sc{\grave{e}}ne$ la $pi{\grave{e}}ce$ de Genet. Ils se $diff{\grave{e}}rent$ l'un et l'autre: Lee incite le discours de la classe sociale dans le spectacle, et Park y incite le discours du $d{\acute{e}}sir$. La $diff{\acute{e}}rence$ des signes dans la $relativit{\acute{e}}$ apporte la $diff{\acute{e}}rence$ de la signification de discours $th{\acute{e}}{\hat{a}}tral$, et enfin se font changer les significations de deux spectacles.

• 동의생리병리학회지
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• 제21권5호
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• pp.1081-1086
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• 2007

This study was performed to investigate the medicinal effects of the herbal combination extracts-2 (HCE-2), consisting of Artemisia capillaris Thunb., Lonicera japonica Thunb., Prunella vulgaris var. lilacina, and Hovenia dulcis Thunb. on the alcohol-induced liver injury in rats. The rats were randomly divided into four groups: normal group (n =6), non-treated control group (n =6), saline-treated group (n =6) and the herbal combination extract (HCE-2)-treated group (n =6). The rats in the alcohol-loaded groups were orally administered with ethanol at a daily dose of 4 g/kg-body weight for 5 weeks. Thirty minutes before the ethanol injection, saline or herbal combination extracts was administered by using a gastrogavage. Blood and liver tissue samples were taken out from the hearts and livers of the rats, respectively, on 15th and 38th days. The activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured using an enzyme-linked immunosorbent assay (ELISA). We also investigated the protective effect of the herbal combination extracts by Hematoxylin-Eosin staining on histological sections of rat liver. In this study, the oral administration of the herbal combination extracts significantly reduced the serum levels of AST and ALT, which had been raised by alcohol-induced liver injury. Histological analysis and apparent observation of liver also showed the preventive effect of the herbal combination extracts in a chronic alcohol-induced rat model. Theses results revealed that the herbal combination extracts effectively prevented hepatic damage consequent to the chronic exposure to repetitive administration of ethanol and could be used as a primary resource of a health beverage or herbal medicine, alleviating the alcohol-induced hepatic injury and hangover symptoms.

• 대한원격탐사학회지
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• 제39권5_4호
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• pp.1135-1144
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• 2023

국내 농업용 저수지는 1970년 이전에 축조되어 준공 년도가 50년 이상 된 노후화된 시설이 대다수이며, 소규모 저수지는 기본 제원 및 수위 등을 파악할 수 있는 계측시스템이 없는 미계측 저수지이다. 준공 이후 호우발생 시 퇴적된 토사 유입, 퇴사량 증가에 따른 저수지 용량 감소 및 산업 고도화에 따른 수질악화 등은 저수지의 용수공급능력을 저하시키고 형상 변화를 야기한다. 따라서, 디지털 정보 및 원격탐사 정보를 결합한 계측 기술을 활용하여 미계측 저수지 수체 모니터링을 위한 공간정보 구축 방안이 필요하다. 본 연구에서는 지표면의 고도정보와 형태를 파악할 수 있는 Light Detection And Ranging (LiDAR) 센서를 활용하여 저수지 시설물의 고해상도 Digital Surface Model (DSM), Digital Elevation Model (DEM) 자료를 구축하고, 멀티빔(MultiBeam) 음향 측심기 기반 수심측량 정보의 융합을 통해 디지털 공간정보 융합 방안을 제시하고자 한다. 드론용 LiDAR를 활용하여 공간해상도 50 cm의 DSM 및 DEM 자료를 구축하여, 저수지 제방, 여수로, 용수로 등의 수리시설물의 디지털 공간정보를 구축하였다. 다분광 영상을 활용하여 수체를 탐지하기 위해 정규식생지수(Normalized Difference Vegetation Index, NDVI), 정규수분지수(Normalized Difference Water Index, NDWI)를 산정하여, 저수지의 수표면을 산정하였다. 또한, 고해상도 DEM 자료는 수심측량 자료와 융합하여 수심도를 작성하였으며, Triangulated Irregular Network (TIN)로부터 저수지 만수면적 및 체적을 산정하였다. LiDAR 센서 및 멀티빔 기반의 수심측량, 광학위성자료 영상 및 다중분광 드론영상을 활용한 수체 탐지 기술 등의 공간정보 융합은 미계측 저수지의 디지털 인프라를 구축하여 저수지의 가용용수공급능력을 모니터링 하기 위한 기초자료로서 활용성이 높을 것으로 사료된다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 1998년도 가을 학술발표회 프로그램
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• pp.2-4
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• 1998

Proliferation of Nocardia amarae cells in activated sludge has often been associated with the generation of nuisance foams. Despite intense research activities in recent years to examine the causes and control of Nocardia foaming in activated sludge, the foaming continued to persist throughout the activated sludge treatment plants in United States. In addition to causing various operational problems to treatment processes, the presence of Nocardia may have secondary effects on the fate of heavy metals that are not well known. For example, for treatment plants facing more stringent metal removal requirements, potential metal removal by Nocardia cells in foaming activated sludge would be a welcome secondary effect. In contrast, with new viosolid disposal regulations in place (Code o( Federal Regulation No. 503), higher concentration of metals in biosolids from foaming activated sludge could create management problems. The goal of this research was to investigate the metal sorption property of Nocardia amarae cells grown in batch reactors and in chemostat reactors. Specific surface area and metal sorption characteristics of N. amarae cells harvested at various growth stages were compared. Three metals examined in this study were copper, cadmium and nickel. Nocardia amarae strain (SRWTP isolate) used in this study was obtained from the University of California at Berkeley. The pure culture was grown in 4L batch reactor containing mineral salt medium with sodium acetate as the sole carbon source. In order to quantify the sorption of heavy metal ions to N amarae cell surfaces, cells from the batch reactor were harvested, washed, and suspended in 30mL centrifuge tubes. Metal sorption studies were conducted at pH 7.0 and ionlc strength of 10-2M. The sorption Isotherm showed that the cells harvested from the stationary and endogenous growth phase exhibited significantly higher metal sorption capacity than the cells from the exponential phase. The sequence of preferential uptake of metals by N. amarae cells was Cu>Cd>Ni. The specific surFace area of Nocardia cells was determined by a dye adsorption method. N.amarae cells growing at ewponential phase had significantly less specific surface area than that of stationary phase, indicating that the lower metal sorption capacity of Nocardia cells growing at exponential phase may be due to the lower specific surface area. The growth conditions of Nocardia cells in continuous culture affect their cell surface properties, thereby governing the adsorption capacity of heavy metal. The comparison of dye sorption isotherms for Nocardia cells growing at various growth rates revealed that the cell surface area increased with increasing sludge age, indicating that the cell surface area is highly dependent on the steady-state growth rate. The highest specific surface area of 199m21g was obtained from N.amarae cell harvested at 0.33 day-1 of growth rate. This result suggests that growth condition not only alters the structure of Nocardia cell wall but also affects the surface area, thus yielding more binding sites of metal removal. After reaching the steady-state condition at dilution rate, metal adsorption isotherms were used to determine the equilibrium distributions of metals between aqueous and Nocardia cell surfaces. The metal sorption capacity of Nocardia biomass harvested from 0.33 day-1 of growth rate was significantly higher than that of cells harvested from 0.5- and 1-day-1 operation, indicatng that N.amarae cells with a lower growth rate have higher sorpion capacity. This result was in close agreement with the trend observed from the batch study. To evaluate the effect of Nocardia cells on the metal binding capacity of activated sludge, specific surface area and metal sorption capacity of the mixture of Nocardia pure cultures and activated sludge biomass were determined by a series of batch experiments. The higher levels of Nocardia cells in the Nocardia-activated sludge samples resulted in the higher specific surface area, explaining the higher metal sorption sites by the mixed luquor samples containing greater amounts on Nocardia cells. The effect of Nocardia cells on the metal sorption capacity of activated sludge was evaluated by spiking an activated sludge sample with various amounts of pre culture Nocardia cells. The results of the Langmuir isotherm model fitted to the metal sorption by various mixtures of Nocardia and activated sludge indicated that the mixture containing higher Nocardia levels had higher metal adsorption capacity than the mixture containing lower Nocardia levels. At Nocardia levels above 100mg/g VSS, the metal sorption capacity of activate sludge increased proportionally with the amount of Noeardia cells present in the mixed liquor, indicating that the presence of Nocardia may increase the viosorption capacity of activated sludge.