• Journal of Wetlands Research
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• v.14 no.2
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• pp.243-254
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• 2012

Recently, the use of radar rainfall data that can help tracking of the development and movement of rainfall's spatial distribution is drawing much attention in hydrology. The reliability of existing radar rainfall compared to gauge rainfall data on the ground has not yet been confirmed and so we have difficulties to apply the radar rainfall in hydrology. The radar rainfall for the applications in hydrology are adjusted merging method derived from gage. This study uses the Mean-Field Bias (MFB) and Statistical Objective Analysis (SOA) as correction methods to create adjusted grid-based radar rainfall data which can represent the temporal and spatial distribution of rainfall. This study used a storm event occurred in August 2010 for the adjustment of radar rainfall. In addition, the grid-based distributed rainfall-runoff model (Vflo), which enables more detailed examinations of spatial flux changes in the basin rather than the lumped hydrological models, has been applied to Gamcheon river basin which is a tributary of Nakdong River located in south-eastern part of the Korean peninsular and the basin area is $1005km^2$. The simulated runoff was compared with the observed runoff in an attempt to evaluate the usability of radar rainfall data and the reliability of the correction methods. The error range of peak discharge using each correction method was within 20 percent and the efficiency of the model was between 60 and 80 percent. In particular, the SOA method showed better results than MFB method. Therefore, the SOA method could be used for the adjustment of grid-based radar rainfall and the adjusted radar rainfall can be used as an input data of rainfall-runoff models.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.343-351
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• 2016

Cryogenic spray characteristics of a nitrogen swirl injector operating in supercritical environment have been numerically investigated. By comparing the equation of states(EOS) used for supercritical condition, SRK EOS was applied to predict the nitrogen thermodynamic property under supercritical environment. A Chung's method was implemented for the calculation of viscosity and conductivity and Takahashi's correlation based on Fuller's Theorem was implemented for the calculation of diffusion coefficient. By injecting the nitrogen with 5 bar differential pressure into 50 bar chamber filled with nitrogen, numerical simulation has been conducted. The dynamic Smagorinsky sub-grid scale (SGS) model has been compared with the algebraic Smagorinsky SGS model using FFT frequency analysis. The instability at the liquid film and gas core inside injector and the propagation of pressure oscillation into the injector has been investigated. The spreading angle of swirl injector obtained by numerical calculation has been validated with experimental result.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2002.03b
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• pp.127-141
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• 2002

GIS환경에서 도시모형(urban model)의 적용을 목적으로 사회·경제적 데이터(socio-economic data)를 활용하는 과정은 도시현상이 갖는 복잡성과 변동성으로 인해 하나의 특정시간에서의 상황을 그대로 저장한 형태인 스냅샷 모형(snapshot model)만으로는 효율적인 공간분석의 실행이 불가능하다. 또한 도시모형을 적용하는 과정에서 GIS의 대상이 되는 공간, 속성, 시간의 정의는 분석목적에 따라 다르게 정의되어질 수 있으며 이에 따라 상이한 결과가 도출될 수 있다. 본 연구는 30년 간의 부산시 인구분포의 동적 변화과정 관측을 위해 시간개념을 결합한 Temporal GIS를 구축하고 이를 활용하여 인구밀도모형 및 접근성모형을 적용하는 과정을 통해 보다 효율적이고 다양한 결과를 제시할 수 있는 GIS 활용방안을 제시하고자 하였다. 흔히 공간현상의 계량화와 통계적 기법의 적용을 위한 데이터 처리과정은 많은 오차와 오류를 유발할 수 있다. 이러한 문제의 해결을 위해서는 우선적으로 분석목적에 맞는 데이터의 정의(Data Definition), 적용하고자 하는 모형(Model)의 유용성 검증, 적절한 분석단위의 설정, 결과해석의 객관적 접근 등이 요구된다. 이와 더불어 변동성 파악을 위한 시계열 자료의 효율적 처리를 위한 방법론이 마련되어져야 한다. 즉, GIS환경에서의 도시모형의 적용에 따른 효율성과 효과성의 극대화를 위해서는 분석목적에 맞는 데이터모델의 설정과 공간DB의 구축방법이 이루어져야 하며 분석가능한 데이터의 유형에 대한 충분한 고려와 적용과정에서 분석결과에 중대한 영향을 미칠 수 있는 요소들을 미리 검증하여 결정하는 순환적 의사결정과정이 필요하다., 표준패턴을 음표와 비음표의 두개의 그룹으로 나누어 인식함으로써 DP 매칭의 처리 속도를 개선시켰고, 국소적인 변형이 있는 패턴과 특징의 수가 다른 패턴의 경우에도 좋은 인식률을 얻었다.r interferon alfa concentrated solution can be established according to the monograph of EP suggesting the revision of Minimum requirements for biological productss of e-procurement, e-placement, e-payment are also investigated.. monocytogenes, E. coli 및 S. enteritidis에 대한 키토산의 최소저해농도는 각각 0.1461 mg/mL, 0.2419 mg/mL, 0.0980 mg/mL 및 0.0490 mg/mL로 측정되었다. 또한 2%(v/v) 초산 자체의 최소저해농도를 측정한 결과, B. cereus, L. mosocytogenes, E. eoli에 대해서는 control과 비교시 유의적인 항균효과는 나타나지 않았다. 반면에 S. enteritidis의 경우는 배양시간 4시간까지는 항균활성을 나타내었지만, 8시간 이후부터는 S. enteritidis의 성장이 control 보다 높아져 배양시간 20시간에서는 control 보다 약 2배 이상 균주의 성장을 촉진시켰다.차에 따른 개별화 학습을 가능하게 할 뿐만 아니라 능동적인 참여를 유도하여 학습효율을 높일 수 있을 것으로 기대된다.향은 패션마케팅의 정의와 적용범위를 축소시킬 수 있는 위험을 내재한 것으로 보여진다. 그런가 하면, 많이 다루어진 주제라

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.214-214
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• 1999

다이아몬드를 반도체용 열방산용기판 등으로 사용하기 위해서는 수백 $\mu\textrm{m}$ 두께의 대면적 웨이퍼가 요구된다. 이를 위해서 DC are jet CVD, MW PACVD, DC PACVD 등이 개발되어, 현재 4"에서 8"까지의 많은 문제를 일으키고 있다. 본 연구에서는 multi-cathode DC PACVD법에 의한 4" 다이아몬드 웨이퍼의 합성과 합성된 막의 특성변화에 대한 연구를 수행하였다. 또한, 웨이퍼의 휨과 crack 발생거동과 대한 고찰을 통래 휨과 crack이 없는 웨이퍼의 제작방법을 고안하였다. 사용된 음극의 수는 일곱 개이며, 투입된 power는 각 음극 당 약 2.5kW(4.1 A-600V)이었다. 사용된 기판의 크기는 직경 4"이었다. 합성압력은 100Torr, 가스유량은 150sccm, 증착온도는 125$0^{\circ}C$~131$0^{\circ}C$, 수소가스네 메탄조성은 5%~8%이었다. 합성 중 막에 인가되는 응력은 합성 중 증착온도의 변화에 의해 제어하였다. 막의 결정도는 Raman spectroscopy 및 열전도도를 측정을 통해 분석하였다. 성장속도 및 다이아몬드 peak의 반가폭은 메탄조성 증가(5%~8%)에 따라 증가하여 각각 6.6~10.5$\mu\textrm{m}$/h 및 3.8~5.2 cm-1의 분포를 보였다. 6%CH4 및 7%CH4에서 합성된 웨이퍼에서 측정된 막의 열전도도는 11W/cmK~13W/cmK 정도로 높게 나타났다. 막두께의 uniformity는 최대 3.5%로 매우 균일하였다. 막에 인가되는 응력의 제어로 직경 4"k 합성면적에서 두께 1mm 이상의 균열 및 휨이 없는 다이아몬드 자유막 웨이퍼를 합성할 수 있었다.다이아몬드 자유막 웨이퍼를 합성할 수 있었다.active ion에 의해 sputtering 이 된다. 이때 plasma 처리기의 polymer 기판 후면에 magnet를 설치하여 높은 ionization을 발생시켜 처리 효과를 한층 높여 주었다. 이 plasma 처리는 표면 청정화, 표면 etching 이 동시에 행하는 것과 함께 장시간 처리에 의해 표면에서는 미세한 과, C=C기, -C-O-의 극성기의 도입에 의한 표면 개량이 된다는 것을 관찰할 수 있다. OPP polymer 표면을 Ar 100%로 plasma 처리한 경우 C-O, C=O 등의 carbonyl가 발생됨을 알 수 있었다. C-O, C=O 등의 carbynyl polor group이 도입됨에 따라 sputter된 Al의 접착력이 향상됨을 알 수 있으며, TEM 관찰 결과 grain size도 상당히 작아짐을 알 수 있었다.onte-Carlo 방법으로 처리하였다. 정지기장해석의 경우 상용 S/W인 Vector Fields를 사용하였다. 이를 통해 sputter 내 플라즈마 특성, target으로 입사하는 이온에너지 및 각 분포, 이들이 target erosion 형상에 미치는 영향을 살펴보았다. 또한 이들 결과로부터 간단한 sputtering 모델을 사용하여 target으로부터 sputter된 입자들이 substrate에 부착되는 현상을 Monte-Carlo 방법으로 추적하여 성막특성도 살펴보았다.다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상

• Journal of Korean Society of Steel Construction
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• v.26 no.1
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• pp.43-53
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• 2014

A single plate connection(SPC) consists of a plate welded to the columns and bolts connected to the beam web. The SPC is widely used for a simple shear connection of steel structure because it is easy-to-fabricated, easy-to-installed and economical. The conventional SPC is used for 2 to 12 bolts in a single vertical row. It is designed to limit the plate thickness by bolt diameter to obtain flexible and ductile connections. The design strength for eccentric shear shall be the lesser of the shear strength of bolts or bearing strength of plate and when the design strength is decided by edge distance failure, the results can be very conservative. Although the research on special solution for 'weak-plate/strong-bolt' model with 2 to 4 bolts has been conducted by L. S. Muir, and W. A. Thonton, 2004, study on generalized design procedures did not conduct. This study proposed design procedure for evaluation of the design strength of eccentric shear bolt groups on a single plate connection based on the actual edge distance and the direction of bolt reaction forces by using elastic vector method(EVM) and instantaneous center of rotation method(ICM).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.505-513
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• 2010

This study investigate the characteristics of tidal constituents, and long-term mean sea level oscillations at Incheon bay. For this, the conditions of three tide stations around Incheon bay have examined, and carried out harmonic analysis on water level data for periods of about 40 years(1960~2007). Four major tidal constituents($M_2$, $S_2$, $K_1$, $O_1$) of each tide station showed tendency that change over the 18.61year lunar node cycle, and the type of tide at three stations is mainly semi-diurnal tides. And also, the past monthly tidal modulations are especially sensitive to the cumulative year of water level data in accuracy of tidal prediction. In case that regard the detached data at three tide stations as a single time series data of 40 years, the results of analysis on a single time series, long-term mean sea level oscillations and modulations of tidal datum at tide stations appears with a range of about 10cm, respectively. In addition, the predicted tides at the Inchcon harbor by global and regional tide models of OSU(Oregon State University) based on various satellite altimetric(Topex Poseidon, Topex Tandem, ERS, GFO) data are compared with the observed tides by KHOA(the Korea Hydrographic and Oceanographic Administration). The results show that the high resolution regional model is a quite good agreement at coastal shallow water region.

• Journal of the Korean Institute of Gas
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• v.7 no.4 s.21
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• pp.44-52
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• 2003

In this work dynamic heat transfer in a CPFS (cable penetration fire stop) system built in the firewall of nuclear power plants is three-dimensionally investigated to develop a test-simulator that can be used to verify effectiveness of the sealant. Dynamic heat transfer in the fire stop system is formulated in a parabolic PDE (partial differential equation) subjected to a set of initial and boundary conditions. First, the PDE model is divided into two parts; one corresponding to heat transfer in the axial direction and the other corresponding to heat transfer on the vertical planes. The first PDE is converted to a series of ODEs (ordinary differential equations) at finite discrete axial points for applying the numerical method of SOR (successive over-relaxation) to the problem. The ODEs are solved by using an ODE solver In such manner, the axial heat flux can be calculated at least at the finite discrete points. After that, all the planes are separated into finite elements, where the time and spatial functions are assumed to be of orthogonal collocation state at each element. The initial condition of each finite element can be obtained from the above solution. The heat fluxes on the vertical planes are calculated by the Galerkin FEM (finite element method). The CPFS system was modeled, simulated, and analyzed here. The simulation results were illustrated in three-dimensional graphics. Through simulation, it was shown clearly that the temperature distribution was influenced very much by the number, position, and temperature of the cable stream, and that dynamic heat transfer through the cable stream was one of the most dominant factors, and that the feature of heat conduction could be understood as an unsteady-state process.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.283-289
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• 2021

Adsorption characteristics of carbol fuchsin (CF) dye by coal-based activated carbon (CAC) were investigated using pH, initial concentration, temperature and contact time as adsorption variables. CF dissociates in water to have a cation, NH₂⁺, which is bonded to the negatively charged surface of the activated carbon in the basic region by electrostatic attraction. Under the optimum condition of pH 11, 96.6% of the initial concentration was adsorbed. Isothermal adsorption behavior was analyzed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models. Langmuir's equation was the best fit for the experimental results. Therefore, the adsorption mechanism was expected to be adsorbed as a monolayer on the surface of activated carbon with a uniform energy distribution. From the evaluated Langmuir's dimensionless separation coefficients (R_L = 0.503~0.672), it was found that CF can be effectively treated by activated carbon. The adsorption energies determined by Temkin and Dubinin-Radushkevich models were E = 15.31~7.12 J/mol and B = 0.223~0.365 kJ/mol, respectively. Therefore, the adsorption process was physical (E < 20 J/mol, B < 8 kJ/mol). The experimental result of adsorption kinetics fit better the pseudo second order model. In the adsorption reaction of CF dye to CAC, the negative free energy change increased as the temperature increased. It was found that the spontaneity also increased with increasing temperature. The positive enthalpy change (40.09 kJ/mol) indicated an endothermic reaction.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.760-769
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• 2023

A numerical simulations were performed to investigate the storm surge during the passage of Typhoon Maemi on the coast of Busan. The typhoon landed on the southern coasts of Korean Peninsula at 21:00, September 12, 2003 with a central pressure of 950 hPa, and the typhoon resulted on the worst coastal disaster on the coast of Busan in the last decades. Observed storm surges at Busan, Yeosu, Tongyoung, Masan, Jeju and Seogwipo harbors during the passage of the typhoon were compared with the computed data. The simulated storm surge time series were in good agreement with the observations. The simulated peak storm surges were estimated to be 230 cm at Masan harbor, 200 cm at Yeosu harbor and Tongyoung harbor, and 75 cm at Busan harbor. The computed storm surges along the east coast of Busan measure 52 to 55 cm, exhibiting a gradual reduction in surge height as one moves further from the coast of Busan. Therefore, coastal inundation due to the storm surge in the semi-enclosed bay can induce great disasters, and the simulated results can be used as the important data to reduce the impact of a typhoon-induced coastal disaster in the future.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.115-123
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• 2013

Stoker type incinerator is one of the most popular one used as municipal solid waste (MSW) incineration because, in general, it is quite suitable for large capacity and need no preprocessing facility. Nowadays, however, since the combustible portion of incoming MSW increases together with the decrease of the moisture content due to prohibition of directly burying food waste in landfill, the heating value of waste is remarkably increasing in comparison with the early stage of incinerator installation. Consequently, the increased heating value in incinerator operation causes a number of serious problems such as reduction of waste amount to be burned due to the boiler heat capacity together with the significant NO generation in high temperature environment. Therefore, in this study, a series of numerical simulation have been made as parameters of waste amount and the fraction of moisture in air stream in order to investigate optimal operating condition for the resolution of the problems associated with the high heating value of waste mentioned above. In specific, a detailed turbulent reaction flow field calculation with NO model was made for the full scale incinerator of D city. To this end, the injection method of moisturized air as oxidizer was intensively reviewed by the addition of moisture water amount from 10% and 20%. The calculation result, in general, showed that the reduction of maximum flame temperature appears consistently due to the combined effects of the increased specific heat of combustion air and vaporization heat by the addition of water moisture. As a consequence, the generation of NOx concentration was substantially reduced. Further, for the case of 20% moisture amount stream, the afterburner region is quite appropriate in temperature range for the operation of SNCR. This suggests the SNCR facility can be considered for reoperation. which is not in service at all due to the increased heating value of MSW.