• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.53-69
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• 2024

The solubility of Cloxacillin sodium in ethanol, 1-propanol, isopropanol, and acetone solutions was measured at different temperatures. The melting property was also tested by using a differential scanning calorimeter (DSC). Then, the solubility data were fitted using Apelblat equation and λh equation, respectively. The Wilson model and NRTL model were not utilized to correlate the test data, since Cloxacillin sodium will decompose directly after melting. For comparison purposes, the four empirical models, i.e., Apelblat equation, λh equation, Wilson model and NRTL Model, were evaluated by using 1155 solubility curves of 103 solutes tested under different monosolvents and temperatures. The comparison results indicate that the Apelblat equation is superior to the others. Furthermore, a new method (named the calculation method) for determining the Apelblat equation using only three data points was proposed to solve the problem that there may not be enough solute in the determination of solubility. The log-logistic distribution function was used to further capture the trend of the correlation and to make better quantitative comparison between predicted data and the experimental ones for the Apelblat equation determined by different methods (fitting method or calculation method). It is found that the proposed calculation method not only greatly reduces the number of test data points, but also has satisfactory prediction accuracy.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.58.2-58.2
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• 2012

Wilson and Bappu (1957), for the first time, and other precedent studies (Lutz & Kelker 1975; Pasquini et al. 1988; Dupree & Smith 1995; Wallerwstein et al. 1999; Pace et al. 2003) found a tight correlation (called Wilson-Bappu relationship - WBR) between stellar absolute visual magnitude and the width of the Ca II K line emission feature for late type stars. Here we re-visit WBR to claim that WBR can be an excellent indicator of stellar surface gravity of late type stars as well as a good indicator of distance. We have analyzed 103 high-resolution spectra of G, K and M type stars obtained by UVES and BOES by following the method by Pace et al. (2003) for measuring the widths of Ca II K lines(W). WBR found in our samples is Mv=33.26-17.79logW and the correlation is very tight. In this study, the stellar gravity(log g) has been derived using Kurucz ALAS9 model grid and MOOG code, which can determine $T_{eff}$ and [M/H] too.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.59.2-59.2
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• 2013

Wilson and Bappu found a tight correlation between the stellar absolute visual magnitude (MV) and the width of the Ca II K emission line for late-type stars in 1957. Here, we revisit the Wilson-Bappu relationship (hereafter, WBR) to claim that WBR can be an excellent indicator of stellar surface gravity of late-type stars as well as a distance indicator. We have measured the width (W) of the Ca II K emission line in high resolution spectra of 125 late-type stars, which were obtained with Bohyunsan Optical Echelle Spectrograph (BOES) and adopted from the UVES archive. Based on our measurement of the emission line width (W), we have obtained a WBR of $M_V=33.76-18.00{\log}W$. In order to extend the WBR to be a surface gravity indicator, the stellar atmospheric parameters such as effective temperature ($T_{eff}$), surface gravity (logg), metallicity ([Fe/H]), and micro-turbulence (${\xi}_{tur}$) have been derived from the self-consistent detailed analysis using the Kurucz stellar atmospheric model and the abundance analysis code, MOOG. Using these stellar parameters and logW, we found that ${\log}g=-5.85\;{\log}W+9.97\;{\log}T_{eff}-23.48$ for late-type stars.

• Journal of the Korean Institute of Gas
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• v.13 no.5
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• pp.20-25
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• 2009

Low explosion limits of flammable liquid mixtures can be calculated with the appropriate use of the fundamental laws of Raoult, Dalton, Le Chatelier and activity coefficient models. In this paper, Raoult's law, van Laar equation and Wilson equation are shown to be applicable for the prediction of the lower explosion limits for ethylacetate+ethanol and ethanol+toluene systems. The calculated values based on Raoult's law were found to be better than those based on van Laar and Wilson equations.

• Journal of Korean Society of Transportation
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• v.1 no.1
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• pp.43-47
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• 1983

Within the conventional transportation planning process, "trip distribution" has a significant role to play. The most widely applied trip distribution model is the gravity model, for which Wilson provided the theoretical basis in 1967. The concept of the gravity model, however, still remains ambiguous if we analyze the "trip distribution" with a disaggregate data set. Thus, this paper hypothesizes that the gravity technique is still valid even with the disaggregate data set, by proving that the estimated coefficients of the gravity model, which is derived under the principle of entropy maximization, are identical with those of the multinomial logit model, which is derived under the principle of individual utility maximization.tility maximization.

• Journal of Korean Society of Transportation
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• v.12 no.4
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• pp.53-63
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• 1994

도시확산과 지방분권화의 시대적 추세는 도시경제 및 교통-토지이용모형의 구조에 도 영향을 미치고 있다. 첫째, 도시의 공간적 확산과 고밀도화로 인한 도시내 제반 경제.사 회활동이 이전보다는 훨씬 다양해지고 복잡해지고 있다. 둘째, 지방분권화로 인해 대도시내 작은 지역단위별 주민들이 자신의 지역문제에 대한 관심과 요구들이 증가하고 있다. 또한 대부분의 도시계획 및 정책은 대도시내 공간적으로 뿐만 아니라 서로 다른 이익집단에 상이 한 영향을 미치는 것으로 파악되고 있다. 이러한 요인으로 인해 대도시 모형은 1) 도시내 제반활동의 흐름을 체계적으로 분석할 수 있어야 하며, 2) 도시계획 및 정책의 효과를 도시 내 세분화된 공간별, 업종별로 분석할 수 있어야 한다. 본 연구는 Wilson의 모형에 도시내 중요한 경제활동인 통근과 shopping변수를 추가하여 Wilson의 모형이 대도시모형으로 이용 될 때 발생하는 문제를 해결하였다. 또한 모형을 구성함에 있어 Matrix Inversion과 Non-linear Programming Model의 두 가지 방법을 도입하고 그 장단점을 비교하였다. Matrix Inversion의 경우 해 (Solution)을 찾기가 쉬워 실질적이고 승수계산과정에서 각 Round마다 승수의 크기를 알 수 있는 반면 Programming을 통한 모형의 경우 제약식의 도 입이 용이하고 목적함수의 형태를 바꾸는 것이 가능하므로 이론적 기틀을 세우는데 유리한 접근방법으로 분석되었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3764-3773
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• 2012

In this study, modeling and optimization works were completed for the separation of 99.9 mol% of methyl ethyl ketone from water through a pressure-swing distillation process since the azeotropic composition varies very sensitively with the change of system pressure. PRO/II with PROVISION release 9.1 was used for the computer simulation and Wilson activity coefficient model was chosen as a modeling equation. A pressure-swing distillation process can be classified into a low-high pressure columns configuration and a high-low pressure columns configuration. In this work, each configurations were optimized for the minimization of steam consumptions, respectively and were compared.

• Journal of Korea Port Economic Association
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• v.37 no.3
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• pp.75-91
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• 2021

Due to increased competition in supply side to reduce operational costs, port professionals have experienced extreme pressure, which demanded academicians to develop the model for efficient port operations from the industry perspective. Among many ports in the world, U.S. ports are our primary interest to analyze in our study for its high volume of cargoes transacted in the U.S. ports. We primarily employed DEA (Data Envelopment Analysis) technique to research the productivity of U.S. ports and applied the algorithm of double bootstrapped DEA proposed by Simar & Wilson (2007) to further investigate the driving forces of the performance of U.S. port operations. The external variables employed in our study comprise onDock Rail, Channel Depth, Location, Area, Acres, ForeignCargoRatio, and TEUChange, out of which onDock Rail, Acres, ForeignCargoRatio, and TEUChange were significant. In order to evaluate the effects of methodology selection, we conducted the same analysis applying the Censored model (Tobit) and contrasted the outcomes drawn from the two different techniques. Based on the findings from this work we proposed managerial implications and concluded.

• Journal of Astronomy and Space Sciences
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• v.18 no.1
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• pp.55-62
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• 2001

We present VRI CCD photometry of W UMa type binary TY UMa. The light curves show that the secondary minimum is deeper than the primary minimum and the maximum I ($0.^{p}25$)is $0.^{m}023$ brighter than the maximum II ($0.^{p}75$). The V light curve has been analyzed and the photometric solutions have been determined by the method of Wilson & Devinney differential correction. We adopted the spot model to explain the asymetric light curve.

• Korean Journal of Cognitive Science
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• v.3 no.1
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• pp.113-137
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• 1991

Coherence and relevaned concern the ways in which discouse is interpreted.In this inversigation, the notions of coherence and relevance are discussed with examples in which they account for discourse interpretation and Charolles's(1983)procedural model of coherence is compared and combined with Sperber & Wilson's(1986a)Principle of Relevance. It is shown that the notion of coherence is not adeqiately established, but that the procedural approach will be a bridge between the prinxiples of coherence and relevance, each of which still remainas to be enriched and completed.