• Mass Spectrometry Letters
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• 제6권4호
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• pp.105-111
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• 2015

Sixteen compounds of Neobalanocarpus heimii were successfully identified directly from their plant extract using a triple quadrupole LC-MS/MS system. In order to fulfil the objectives of this work, a series of stilbene oligomers of various degrees of condensation were isolated and their structure are characterized. Out of these, four are resveratrol dimers, three trimers, and nine tetramers. The isolation process was done on a fully automated semi-preparative HPLC system. Their structures were elucidated on the basis of 1D- and 2D-NMR as well as MS data. The mass fragmentation patterns of the compounds were recorded and a retrievable in-house library was built to keep the data. In order to demonstrate the potential of this approach, the polyphenolic crude extract was analysed with the LC-MS/MS system and the MS/MS spectra extracted for each chromatographic peak of interest. The fragmentation patterns were compared with those of anticipated pure compounds that were previously recorded. All compounds were successfully identified. It is therefore believed that the LC-MS/MS potential for dereplication of structurally similar compounds in a crude mixture was thus firmly established.

• 대한전자공학회논문지
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• 제23권2호
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• pp.236-242
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• 1986

The dependence of the current-voltage characteristics of hydrogenated amorphous silicon pin solar cells on the illumimination light intensity has been investigated. The open circuit voltage increases linearly with increasing the logarithm of light intensity up to AM 1, and nearly saturates above AM 1, indicating the open circuit voltage approaching the built-in potential of the pin solar cell above AM 1. The short circuit current density increase with light intensity in proportion to I**0.85 before and I**0.97 after light exposure. Since the series resistance devreses and shunt resistance increases with light intensily, the fill factor increases with light illumination. To increase the fill factor at high illumination in large area solar cells, t6he grid pattern on the ITO substrates should be made. Long light exposure on the solar cells gives rise to the increase of bulk resistance and defect states, resulting in the decrease of the fil factor and short circuit current density. The potential drop in the bulk of the a-Si:H pin solar cells at short circuit condition increases with decreasing temperature, and increases after long light exposure.

• 한국해양공학회지
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• 제32권4호
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• pp.228-236
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• 2018

The performance of a porous swash bulkhead for the reduction of the resonant liquid motion in a swaying rectangular tank was investigated based on the assumption of linear potential theory. The Galerkin method (Porter and Evans, 1995) was used to solve the potential flow model by adding a viscous frictional damping term to the free-surface condition. By comparing the experimental results and the analytical solutions, we verified that the frictional damping coefficient was 0.4. Darcy's law was used to consider the energy dissipation at a porous bulkhead. The tool that was developed with a built-in frictional damping coefficient of 0.4 was confirmed by small-scale experiments. Using this tool, the free-surface elevation, hydrodynamic force (added mass, damping coefficient) on a wall, and the horizontal load on a bulkhead were assessed for various combinations of porosity and submergence depth. It was found that the vertical porous bulkhead can suppress sloshing motions significantly when properly designed and by selecting the appropriate porosity(${\approx}0.1$) and submergence depth.

• International Journal of Computer Science & Network Security
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• 제22권6호
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• pp.400-407
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• 2022

Innovations significantly affect the efficiency of the socioeconomic systems of the regions, acting as a system-forming element of their development. Modern models of economic development also consider innovation activity, intellectual potential, knowledge as the basic factors for stimulating the economic growth of the region. The purpose of the study is to develop methodological foundations for evaluating the effectiveness of a regional innovation system based on a multidimensional analysis of its effects. To further study the effectiveness of RIS, we have used one of the methods of multidimensional statistical analysis - canonical analysis. The next approach allows adding another important requirement to the methodological provision of evaluation of the level of innovation development of industries and regions, namely - the time factor, the formalization of which is realized in autoregressive dynamic economic and mathematical models and can be used in our research. Multidimensional Statistical Analysis for RIS effectiveness estimation was used to model RIS by typological regression. Based on it, multiple regression models were built in groups of regions with low and relatively high innovation potential. To solve the methodological problem of RIS research, we can also use the approach to the system as a "box" with inputs and outputs.

• 한국환경생태학회지
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• 제31권2호
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• pp.252-265
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• 2017

본 연구에서는 고밀 시가화지역 내 녹지들의 경관생태학적 특성과 연결성을 분석함으로써 잠재적인 녹지패치들의 활용가능성을 평가하고, 이를 통해 생활권 내 녹지 네트워크를 형성하기 위한 도시정원의 도입 방안을 제시하고자 한다. 이를 위해, 서울시에서 공원 서비스 소외지역 및 중점녹화지구로 분류된 역삼동 일대를 대상지로 선정하였다. 우선, 대상지 일대 고밀 시가화지역 내 녹지의 현황을 가로녹지, 개인정원, 자투리공지, 공원, 옥상정원의 5개 항목으로 분류하여 파악하고, 녹지 네트워크 분석 및 잠재적 녹지의 가치를 평가하기 위하여 FRAGSTATS를 통한 경관지수 분석 및 다중버퍼생성분석을 통한 연결성평가를 실시하였다. 연구결과, 대상지 내 녹지면적은 가로녹지, 개인정원, 자투리공지, 공원, 옥상정원의 순으로 분포되어 있었다. 녹지의 유형별 특징으로는 가로녹지의 경우 핵심지역면적(TCA)이 $1,618m^2$로 가장 높은 값을 보여 선형 연결 녹지임에도 공원($1,128m^2$)에 상응하는 크기를 보였고, 개인정원의 경우 패치의 모양이 불규칙하면서도(ED=78.1m/ha), 최근린 평균거리가 33.9m로 낮아 사유지내에서의 자유로운 정원조성을 통해 고밀 시가화지역의 녹지군을 형성할 수 있음을 나타내었다. 자투리공지의 경우 대상지 내 가장 고루 분포하는(LPI=5.7%, SHEI=0.9) 녹지유형이나 외부교란에 노출되어 있어($TCA=66m^2$), 이를 고려한 정원으로의 활용방안을 시사하였다. 대상지 내 녹지네트워크 형성에 있어서도 50m의 버퍼 범위를 연결녹지로 상정한 경우 전체 대상지의 84%가 소규모 녹지네트워크에 의해 커버되는 것으로 나타났으며, 자투리공지의 연결만으로도(27%) 가로녹지(26%) 조성에 상응하는 네트워크 구축효과가 기대되었다. 이에, 주택지역을 중심으로 다양한 활동이 가능한 자투리 공공녹지에 지역기반의 커뮤니티 가든 등 도시정원 조성을 장려하고, 가로녹지, 개인정원, 옥상정원도 동시에 적극 활용함으로써 고밀 시가화지역 내에 녹지네트워크를 효과적으로 구축할 수 있다고 판단되었다.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2487-2495
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• 2018

Inspired by the specific amino acid sequence Asn-Pro-Ala (NPA) of water channel aquaporins (AQPs), we fabricated polyamide (PA) nanofiltration (NF) membranes by introducing reduced glutathione (GSH) in interfacial polymerization (IP) method. Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometry (XPS), scanning electron microscope (SEM), atomic force microscopy (AFM), zeta potential and static water contact angle measurement were employed to characterize the chemical composition, morphology, electronegativity and hydrophilicity of the NF membranes. The water flux of GSH/PIP-TMC NF membrane reached $32.00L\;m^{-2}h^{-1}$ at 0.2 MPa, which was approximately twice than that of pristine PIP-TMC NF membrane when the ratio of GHS to piperazidine (PIP) was 40% during IP process. More water channels were built as GSH was embedded into PA layer. The fabricated NF membranes also took on potent rejection for dyes and $Na_2SO_4$. This study presents a simple and facile method to simulate water channels-based biological materials which may find potential application in water treatment.

• Structural Engineering and Mechanics
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• 제76권6호
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• pp.687-708
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• 2020

Openings in steel plate shear walls (SPSWs) are usually used for decorative designs, crossing locations of multiple utilities and/or structural objectives. However, earlier studies showed that generating an opening in an SPSW has a negative effect on the cyclic performance of the SPSW. Therefore, this study proposes tripling or doubling the steel-sheet-plate (SSP) layer and stiffening the opening of the SPSW to provide a solution to undesirable opening effects, improve the SPSW performance and provide the infill option of potential strengthening measures after the construction stage. The study aims to investigate the impact of SSP doubling with a stiffened opening on the cyclic behaviour, expand the essential data required by structural designers and quantify the SPSW performance factors. Validated numerical models were adopted to identify the influence of the chosen parameters on the cyclic capacity, energy dissipation, ductility, seismic performance factors (SPF) and stiffness of the suggested method. A finite Element (FE) analysis was performed via Abaqus/CAE software on half-scale single-story models of SPSWs exposed to cyclic loading. The key parameters included the number of SSP layers, the opening size ratios corresponding to the net width of the SSP, and the opening shape. The findings showed that the proposed assembly method found a negligible influence in the shear capacity with opening sizes of 10, 15, 20%. However, a deterioration in the wall strength was observed for openings with sizes of 25% and 30%. The circular opening is preferable compared with the square opening. Moreover, for all the models, the average value of the obtained ductility did not show substantial changes and the ultimate shear resistance was achieved after reaching a drift ratio of 4.36%. Additionally, the equivalent sectional area of the SSP in the twin and triple configuration of the SPSWs demonstrated approximately similar results. Compared with the single SSP layer, the proposed configuration of the twin SSP layer with a stiffened opening suggest to more sufficiency create SSP openings in the SPSW compared to that of other configurations. Finally, a tabular SPF quantification is exhibited for SPSWs with openings.

• 한국결정성장학회지
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• 제8권4호
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• pp.640-644
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• 1998

Sb/SiC(4H) 및 Ti/SiC(4H) 쇼트키 다이오드(SBD)를 제작하여 그 특성을 조사하였다. 용량-전압(C-V) 측정으로부터 얻은 n-형 SiC(4H)의 주개(donor) 농도는 약 $2.5{\times}10 ^{17}{\textrm}cm^{-3}$이었다. 순방향 전류-전압(I-V) 특성의 기울기로부터 얻은 Sb/SiC(4H) 쇼트키 다이오드의 이상계수는 1.31이었고, 역방향 항복전장(breakdown field)은 약 4.4$\times$102V/cm 이었다. 용량-전압(C-V) 측정으로부터 얻은 Sb/SiC(4H) SBD의 내부전위(built-in potential) 및 쇼트키 장벽 높이는 각각 1.70V 및 1.82V이었다. Sb/SiC(4H)의 장벽높이 1.82V는 Ti/SiC(4H)의 0.91V보다 높았다. 그러나 Sb/SiC(4H)의 전류밀도와 역방향 항복전장은 Ti/SiC(4H)의 것보다 낮았다. Ti/SiC(4H)는 물론 Sb/SiC(4H) 쇼트키 다이오드는 고전력 전자소자로서 유용하다.

• 한국물환경학회지
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• 제31권6호
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• pp.693-699
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• 2015

It has been known that torrential rainfall events have been occurring worldwide due to climate change. The accelerated soil erosion has caused negative impacts on water quality and ecosystem of receiving waterbodies. Since soil security issues have been arising in various areas of the world, intensive interests have been given to topsoil management in Korea. Thus in this study, Web GIS-based computing system of physical, chemical, and biological topsoil quality indices were developed. In this study, five soil quality maps at national scale and top soil erosion potential were prepared for evaluation of soil quality based on soil erosion potential. For this system, the open source Web GIS engine, OpenGeo, was used as core engine of the system. With this system, decision makers or related personnel in areas of soil erosion Best Management Practices (BMPs) would be able to find the most appropriate soil erosion BMPs based on soil erosion potential and soil quality at the area of interest. The Web GIS system would be efficiently used in decision making processes because of ease-of-use interface and scientific data used in this system. This Web GIS system would be efficiently used because this system could provide scientific knowledge to decision makers or stakeholders. Currently various BMP database are being built to be used as a decision support system in topsoil management and topsoil quality areas.

• 한국지능시스템학회논문지
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• 제7권1호
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• pp.34-44
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• 1997

The Belgian Nuclear Research Centre(SCK${\cdot}$CEN) has been a pioneer of the peaceful uses of nuclear energy after over forty years of existence. Recently, SCK${\cdot}$CEN's financial support of doctoral and postdoctoral research in close collaboration with universities has been a vital ingredient for securing a quality profile committed to the pursuit of execllence. FLINS, Fuzzy Logic and Intelligent technologies in Nuclear Science, was initially built within one of the postdoctoral research project at SCK${\cdot}$CEN. Among SCK${\cdot}$CEN's activities which will have an important impact on its scientific future, the application of fuzzy logic and intelligent technologies in nuclear science and engineering opens new domains in radiation protection, safety assessment, human reliability, nuclear reactor control, waste and disposal, etc. In this paper, we review the available literature on fuzzy logic in nuclear applications. We then present the initiative of R&D on fuzzy logic applications at SCK${\cdot}$CEN, namely, (1) safety control for a nuclear reactor, and (2) a safety evaluation model for nuclear transmission lines. By these two examples of nuclear applications, we illustrate the potential use of fuzzy logic in nuclear safety issues.