• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.19-22
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• 2001

The effects of pH on the sequential sorption/desorption of chlorinated phenols (2-chlorophenol, 2.4-dichlorophenol and 2,4,5-trichlorophenol) in HDTMA-montmorillonite were investigated by maintaining pH 4.85 or 9.15 in the sequential batch sorption and desorption experiments. The chlorinated phenols are hydrophobic ionizable orginic compounds; they can exist as either neutral (pH << pKa) or anionic (pH >> pKa) forms. Among the tested chlorinated phenols, 2,4,5-trichlorophenol showed the highest sorption affinity at pH 4.85 as expected by the $K_{ow}$ . Neutral speciation at pH 4.85 exhibited higher sorption affinity than anionic speciation at pH 9.15. Our results indicates that desorption of chlorinated phenols is strongly dependent on pH of the aqueous phase. Freundlich model was used to analyze the single-solute sorption/desorption results. The ideal adsorbed solution theory(IAST) was employed to predict the hi-solute sorption/desorption equilibria.

• 대한기계학회논문집A
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• 제31권1호
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• pp.129-138
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• 2007

In this paper, a modified sensitivity control for the semi-active suspension system with a magneto-rheological (MR) damper is investigated. A 2-d.o.f quarter-car model together with a 6th order polynomial model for the MR damper is considered. For the purpose of suppressing the vertical acceleration of the sprung mass, the square of the vertical acceleration is defined as a cost function and a modified sensitivity control that updates the current input in the negative gradient of the cost function is proposed. The implementation of the proposed algorithm requires only the measurement of the relative displacement of the suspension deflection. The local stability of equilibria of the closed loop nonlinear system is proved by investigating the eigenvalues of the linearized ones. Through simulations, the passive suspension, the skyhook control, and the proposed modified sensitivity control are compared.

• 공업화학
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• 제8권4호
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• pp.653-659
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• 1997

에너지 비용의 상승에 따라 추출의 기본원리를 둔 새로운 분리공정에 대한 연구가 많이 진행되고 있으며, 이에 따라 액-액평형 조성의 계산 및 예측에 대한 필요성이 매우 증가하고 있다. 본 연구에서는 공비혼합물을 형성하는 2-propanol 수용액에 용매로서 methyl ethyl ketone, methyl isobutyl ketone, ethylacetate, butylacetate, toluene 및 o-xylene을 첨가한 삼성분계에 대하여 $25^{\circ}C$에서 용해도곡선, tie line, plait point, 분배계수와 선택도를 실험을 통해 구하였다. Tie line 데이터의열역학적 건전성을 확인하였으며 실험값을 NRTL 및 UNIQUAC 모델식으로 구한 계산값과 비교하였다.

• 대한화학회지
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• 제7권1호
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• pp.65-68
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• 1963

The solubility of ethyl bromide in nitrobenzene and in 1,2,4-trichlorobenzene has been measured at $19^{\circ}$ in the presence and absence of gallium bromide. When gallium bromide does not exist in the system, the solubility of ethyl bromide in nitrobenzene is greater than in 1,2,4-trichlorobenzene, indicating the stronger interaction of ethyl bromide with nitrobenzene than with 1,2,4-trichlorobenzene. When there exists gallium bromide in the system, an unstable 1: 1 complex, C2H5Br·GaBr3, of gallium bromide with ethyl bromide is formed in the solution. The 1: 1 complex in solution dissociates into the components to a large extent according to one of the following equilibria or both: $C_2H_5Br{\cdot}GaBr_3{\rightleftarrows}C_2H_5Br+GaBr_3$C_2H_5Br{\cdot}GaBr_3{\rightleftarrows}C_2H_5Br+1}2GaBr_3$$ The stability of the 1: 1 complex of ethyl bromide with gallium bromide is compared with that of the corresponding complex of methyl bromide.

• 에너지공학
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• 제2권2호
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• pp.225-230
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• 1993

n-dodecane-1-decanol, n-dodecane-1-dodecanol 및 1-decanol-1-dodecanol계 의 14$0^{\circ}C$ 등온 기액평형 데이타를 static method로써 Head Space Gas Chromatography (H.S.G.C)를 이용하여 측정하였다. 액상의 비이상성을 고려하여 계산된 활동도계수는 Margules, Van Laar, Wilson, NRTL g$^{E}$ 모델을 이용하여 상관관계를 구하였으며, Redlich-Kister의 열역학적 일치성 시험을 통해 데이타의 신빙성을 확인하였다. 측정한 이성분계중 n-dodecane-1-decanol계는 최소 공비점을 가짐을 알 수 있었다.

• 천문학회보
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• 제35권2호
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• pp.48.2-48.2
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• 2010

Quiescent filaments are bigger, more stable, and longer lived than active region filaments. So, the shape of a quiescent filament changes little during its lifetime and a fast motion of plasma rarely occurs. But when it is dynamically influenced by external phenomena, a rapid motion of plasma may temporarily occur. By analyzing the motion of plasma we can infer some of the magnetic structure permeating such an excited quiescent filament. We analyzed the H$\alpha$ images of a quiescent filament in the northern hemisphere that was observed at Big Bear Solar Observatory on 2004 August 2, and found that: 1) the filament was excited by a flare that occurred in a remote active region located in the southern hemisphere, 2) By this excitation, a part of the filament moved vertically upward and horizontally out of main body, and then it stayed there without much motion. Then after it moved vertically downward and horizontally to the main body, 3) the final position of plasma, however, was not the same as the initial position, being about 14Mm above it. We suggest that the filament was initially in a more or less static equilibrium. The excitation of the filament broke the initial equilibrium, and then brought about a new one that is different from the original one. Since the filament should have magnetic field, it is likely that both the equilibria may have been maintained by diplike magnetic structures. Furthermore, the transition from one equilibrium to another as we inferred should have accompanied a permanent change of magnetic configuration as well.

• Journal of applied mathematics & informatics
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• 제29권3_4호
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• pp.529-546
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• 2011

A deterministic tuberculosis model for theoretically assessing the potential impact of the combined effects of case detection in the presence of treatment is formulated. The qualitative features of its equilibria are analyzed and it is found that the disease-free equilibrium may not be globally asymptotically stable when the reproduction number is less than unity. This disease threshold number is further used to assess the impact of active TB case finding alone and in conjunction with treatment. A critical threshold parameter ${\Theta}$ say for which case detection will have a positive impact is derived. Using the Centre Manifold theory, the model may exhibit the phenomenon of backward bifurcation (coexistence of a locally stable endemic equilibrium with a stable disease-free equilibrium) when the reproduction number is less than unity. It is shown that the possibility of backward bifurcation occurring decreases with increase case detection. Graphical representations suggest that increase in case finding accompanied by treatment of detected TB cases, result in a marked decrease of TB cases (both latent and active TB).

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2005년도 추계학술발표대회 및 정기총회
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• pp.1125-1128
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• 2005

최근 유비쿼터스 네트워크 환경을 구축하기 위해 많은 무선 통신 기술들이 등장하였다. 그 중 무선랜 기술은 쉬운 설치와 저렴한 비용 덕에 폭발적인 보급이 이루어 졌다. IEEE 802.11 표준을 기반으로 만들어진 무선랜은 여러 개의 전송속도를 지원한다. 대표적으로 802.11b 는 1, 2, 5.5, 11Mbps 의 4 가지 전송속도를 지원한다. 낮은 전송속도로 전송을 하면 패킷 전송시간은 증가하지만 비트 에러율은 감소된다. 각각의 전송속도에 따라 다른 패킷 전송 성공률을 갖게 된다. 한 무선랜 AP 에 연결된 노드들은 각자 자신의 처리율을 최대화할 수 있는 전송속도를 결정하여 사용하게 된다. 이러한 상황은 전체 시스템 성능에는 문제를 발생시킬 수 있다. 본 논문에서는 각자의 전송속도를 각자가 결정하는 것이 전체 시스템 성능에 문제를 발생시키는 경우를 보이고, 그것을 해결하기 위해 AP 가 각 노드의 전송속도 및 전송시간을 결정하는 기법을 제안한다. 나아가 무선랜에서의 문제점인 Performance Anomaly 현상을 해결하고, [3]에서 언급된 Inefficient Equilibria 현상도 막아본다.

• 대한화학회지
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• 제33권6호
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• pp.596-600
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• 1989

25${\circ}$C, 용액의 이온세기 ${\mu}$= 1.0($NaNO_3$) 및 pH 8.0인 조건하에서 카드뮴 -Oxalate-Citrate계의 단일 및 혼합 리간드 착물에 관한 연구를 미분펄스폴라로그라피적으로 수행하였다. DeFord-Hume 및 Schaap-McMasters의 도표법을 이용하여 단일 및 혼합 리간드 착물의 안정도상수 값을 구하였다. $log\beta_{11}$, $log\beta_{12}$ 및 $log\beta_{21}$값은 각각 4.91, 4.99와 5.18이었으며 이들 값으로부터 혼합 리간드 착물계의 여러 평형관계 등을 논의하였다.

• Management Science and Financial Engineering
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• 제19권2호
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• pp.31-36
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• 2013

We propose a war-game model that is appropriate for a raid-type warfare in which, a priori, the maneuver of the attacker is relatively certain. The model is based on a multi-weapon extention of the Lanchester's law. Instead of a continuous time dynamic game with the differential equations from the Lanchester's law, however, we adopt a multi-period model relying on a time-discretization of the Lanchester's law. Despite the obvious limitation that two players make a move only on the discrete time epochs, the pragmatic model has a manifold justification. The existence of an equilibrium is readily established by its equivalence to a finite zero-sum game, the existence of whose equilibrium is, in turn, well-known to be no other than the LP-duality. It implies then that the war-game model dictates optimal strategies for both players under the assumption that any strategy choice of each player will be responded by a best strategy of her opponent. The model, therefore, provides a sound ground for finding an efficient reinforcement of a defense system that guarantees peaceful equilibria.