• Computers and Concrete
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• 제8권2호
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• pp.177-192
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• 2011

This research paper aims at computer based modeling of carbonation induced corrosion under extreme conditions and its experimental verification by incorporating enhanced electrochemical and mass balance equations based on thermo-hygro physics with strong coupling of mass transport and equilibrium in micro-pore structure of carbonated concrete for which the previous research data is limited. In this paper the carbonation induced electrochemical corrosion model is developed and coupled with carbon dioxide transport computational model by the use of a concrete durability computer based model DuCOM developed by our research group at concrete laboratory in the University of Tokyo and its reliability is checked in the light of experiment results of carbonation induced corrosion mass loss obtained in this research. The comparison of model analysis and experiment results shows a fair agreement. The carbonation induced corrosion model computation reasonably predicts the quantitative behavior of corrosion rate for normal air dry relative humidity conditions. The computational model developed also shows fair qualitative corrosion rate simulation and analysis for various pH levels and coupled environmental actions of chloride and carbonation. Detailed verification of the model for the quantitative carbonation induced corrosion rate computation under varying relative conditions, different pH levels and combined effects of carbonation and chloride attack remain as scope for future research.

• 한국건설순환자원학회논문집
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• 제2권4호
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• pp.297-306
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• 2014

Recently nano-materials are gaining more importance in the construction industry due to its enhanced energy efficiency, durability, economy, and sustainability. Nano-silica addition to cement based materials can control the degradation of the fundamental calcium-silicate-hydrate reaction of concrete caused by calcium leaching in water as well as block water penetration and therefore lead to improvements in durability. In this paper, the influence of synthesized nano silica from locally available rice husk on the mechanical properties and corrosion resistant properties of OPC (Ordinary Portland Cement) has been studied by conducting various experimental investigations. Micro structural properties have been assessed by conducting Scanning Electron Microscopy, Thermo gravimetry and Differential Thermal Analysis, X-Ray Diffraction analysis, and FTIR studies. The experimental results revealed that NS reacted with calcium hydroxide crystals in the cement paste and produces Calcium Silicate Hydrate gel which enhanced the strength and acts as a filler which filled the nano pores present in concrete. Hence the strength and corrosion resistant properties were enhanced than the control.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.156-156
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• 2017

Plants are grown under constitutive changing of environmental conditions and response to external conditions at both protein and transcription level. The effects of heat on plant growth are broad and influence the yield directly. Heat stresses could be classified depend on intensity and duration. Fundamental changes of growth condition by climate change maybe or maybe not classified as a stress on plant growth. The effects of a short and unanticipated impact of elevated heat on plant could be different with those of under longer extension of ambient heat. To examine differently expressed gene sets by ambient heat stress of soybean, we grow the soybean in normal condition for three weeks. After that, soybean plants move to growth chamber. The temperature of growth chamber increase up to $9^{\circ}C$ for four days. We have extracted mRNA and micro RNA every 24 hours and carried RNA sequence analysis. We found major metabolic pathways affected by ambient heat stress. Mainly carbon metabolism, translation machinery and amino acid synthesis are affected. We discussed the expression patterns of genes of heat sensing and hormone responses.

• Human Ecology Research
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• 제55권6호
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• pp.567-580
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• 2017

This study explored the influence of adolescent depression on adult media addiction by examining Bronfenbrenner's ecological perspective. The ecological perspective is a useful framework to identify the link between youths' interacting subjects in the ecological environment. It can also be used to understand adolescent problems and addiction behaviors. The current study examined the influence of parents, peers, and teachers on adult media addiction and depression with a focus on micro-systems that have the greatest influence on adolescents among various environmental systems. We analyzed 568 participants who reported exposure to adult media. SPSS 20.0 was used to conduct a descriptive analysis of the data; AMOS 19.0 was used to conduct a confirmatory factor analysis and structural equation model. The results of study are as follows. First, parental abuse and peer alienation significantly increases depression. Second, peer communication significantly decreases depression. Third, parental monitoring and parental affection significantly decreased adult media addiction. Fourth, parental abuse, peer alienation, and depression significantly increased adult media addiction. This study is meaningful in that it examines the influence of parent, peer, and teacher relationships among adolescents on adult media addiction and depression. This study can be helpful to understand adult media addiction and depression among Korean adolescents.

• Steel and Composite Structures
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• 제22권6호
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• pp.1239-1259
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• 2016

The modified couple stress-based third-order shear deformation theory is presented for sigmoid functionally graded materials (S-FGM) plates. The advantage of the modified couple stress theory is the involvement of only one material length scale parameter which causes to create symmetric couple stress tensor and to use it more easily. Analytical solution for dynamic instability analysis of S-FGM plates on elastic medium is investigated. The present models contain two-constituent material variation through the plate thickness. The equations of motion are derived from Hamilton's energy principle. The governing equations are then written in the form of Mathieu-Hill equations and then Bolotin's method is employed to determine the instability regions. The boundaries of the instability regions are represented in the dynamic load and excitation frequency plane. It is assumed that the elastic medium is modeled as Pasternak elastic medium. The effects of static and dynamic load, power law index, material length scale parameter, side-to-thickness ratio, and elastic medium parameter have been discussed. The width of the instability region for an S-FGM plate decreases with the decrease of material length scale parameter. The study is relevant to the dynamic simulation of micro structures embedded in elastic medium subjected to intense compression and tension.

• Toxicological Research
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• 제35권4호
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• pp.319-330
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• 2019

Adverse drug reactions (ADRs) constitute key factors in determining successful medication therapy in clinical situations. Integrative analysis of electronic medical record (EMR) data and use of proper analytical tools are requisite to conduct retrospective surveillance of clinical decisions on medications. Thus, we suggest that electronic medical recording and human genetic databases are considered together in future directions of pharmacovigilance. We analyzed EMR-based ADR studies indexed on PubMed during the period from 2005 to 2017 and retrospectively acquired 1161 (29.6%) articles describing drug-induced adverse reactions (e.g., liver, kidney, nervous system, immune system, and inflammatory responses). Of them, only 102 (8.79%) articles contained useful information to detect or predict ADRs in the context of clinical medication alerts. Since insufficiency of EMR datasets and their improper analyses may provide false warnings on clinical decision, efforts should be made to overcome possible problems on data-mining, analysis, statistics, and standardization. Thus, we address the characteristics and limitations on retrospective EMR database studies in hospital settings. Since gene expression and genetic variations among individuals impact ADRs, pharmacokinetics, and pharmacodynamics, appropriate paths for pharmacovigilance may be optimized using suitable databases available in public domain (e.g., genome-wide association studies (GWAS), non-coding RNAs, microRNAs, proteomics, and genetic variations), novel targets, and biomarkers. These efforts with new validated biomarker analyses would be of help to repurpose clinical and translational research infrastructure and ultimately future personalized therapy considering ADRs.

• 한국지형학회지
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• 제25권4호
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• pp.103-116
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• 2018

The purposes of this research are as follows: First, to reconstruct the optimal locational environment of the Bronze Age settlement in Cheonan Baekseok-dong (hereinafter referred to as the study settlement). Second, to identify the priority ranking of the topographical factors that influenced the Bronze Age people when selecting their the settlement location. For these reasons, the topographical factors of the 200 Bronze Age dwellings (hereinafter referred to as dwellings) confirmed in the survey area were analyzed through the ridge's environmental perspective. The results are asfollows: First, the optimal ridge environment of the Bronze Age settlement is largely a sub-ridge in N-S direction (for example, NNW-SSE, N-S, NNESSW), especially at the top (Crest slope, Crest flat) of the south-facing aspect of the ridge. Second, when the Bronze Age dwellers selected a residential location, they carefully considered topographical factors in the following order: (1) the slope direction of the ridge surface, (2) the micro-landform of the ridge, (3) the ridge scale, (4) the ridge direction, and (5) the surface relief. The results of this study could be used as basic data in related fields such as archaeology, quaternary research, and traditional architecture and so on.

• 한국전기전자재료학회논문지
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• 제35권2호
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• pp.149-154
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• 2022

In this paper, laser-induced fluorescence properties of four plastics were characterized through spectrometer analysis for real-time microplastic counting. Recently, environmental problems related to microplastics have emerged. In order to detect microplastics, analysis methods such as FT-IR and Raman are used. However, they have the disadvantages of being time-consuming and requiring a pretreatment process. In most plastic products on the market, 10% to 30% of plasticizers and reinforcing agents are added. Therefore, most microplastics present in seawater and freshwater emit fluorescence signals by 270 nm UV light source regardless of their type due to their molecular structure due to additives. Real-time microplastics counting is possible more easily by using the proposed laser-induced fluorescence detection method because of the fluorescence expression characteristic of 340 nm that appears due to the plasticizer of plastics.

• Environmental Analysis Health and Toxicology
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• 제28권
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• pp.7.1-7.9
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• 2013

Objectives We investigated the particle mass size distribution and chemical properties of air pollution particulate matter (PM) in the urban area and its capacity to induce cytotoxicity in human bronchial epithelial (BEAS-2B) cells. Methods To characterize the mass size distributions and chemical concentrations associated with urban PM, PM samples were collected by a 10-stage Micro-Orifice Uniform Deposit Impactor close to nearby traffic in an urban area from December 2007 to December 2009. PM samples for in vitro cytotoxicity testing were collected by a mini-volume air sampler with $PM_{10}$ and $PM_{2.5}$ inlets. Results The PM size distributions were bi-modal, peaking at 0.18 to 0.32 and 1.8 to $3.2{\mu}m$. The mass concentrations of the metals in fine particles (0.1 to $1.8{\mu}m$) accounted for 45.6 to 80.4% of the mass concentrations of metals in $PM_{10}$. The mass proportions of fine particles of the pollutants related to traffic emission, lead (80.4%), cadmium (69.0%), and chromium (63.8%) were higher than those of other metals. Iron was the dominant transition metal in the particles, accounting for 64.3% of the $PM_{10}$ mass in all the samples. We observed PM concentration-dependent cytotoxic effects on BEAS-2B cells. Conclusions We found that exposure to $PM_{2.5}$ and $PM_{10}$ from a nearby traffic area induced significant increases in protein expression of inflammatory cytokines (IL-6 and IL-8). The cell death rate and release of cytokines in response to the $PM_{2.5}$ treatment were higher than those with $PM_{10}$. The combined results support the hypothesis that ultrafine particles from vehicular sources can induce inflammatory responses related to environmental respiratory injury.

• 한국전통조경학회지
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• 제34권2호
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• pp.55-62
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• 2016

본 연구는 풍수이론으로 은평뉴타운을 분석하였다. 우선 주거지를 분석하기 위한 틀(천지인합일, 인지제의, 대환경상지분석, 소환경상지분석, 동선상지분석, 주거지조향분석)을 구성하였다. 그 틀로 은평뉴타운을 분석하였으며 결과를 보면 다음과 같다. 광역적으로 분석한 대환경상지분석에서 은평구는 서북향에 산세가 열려 있으므로 겨울 서북풍에 노출되어 불리한 풍수형국으로 나타났다. 소환경상지분석은 사신수형국 기준으로 1지구와 2지구를 구분하여 분석하였다. 분석한 결과 1지구는 배수임산으로 흉지(凶地), 2지구는 비보풍수인 실개천의 복원으로 배산임수의 길지(吉地)로 나타났다. 마지막으로 분석한 결과에 따라 비보풍수 방식을 적용하여 대상지를 길지로 보완하기 위한 대안을 제시하였다.