• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.52-60
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• 2005

The conceptual model of under-sampled study area will include a great amount of uncertainty. In this study, we investigate the applicability of Markov chain model in a spatial domain as a tool for minimizing the uncertainty arose from the lack of data. A new formulation is developed to generalize the previous two-dimensional coupled Markov chain model, which has more versatility to fit any computational sequence. Furthermore, the computational algorithm is improved to utilize more conditioning information and reduce the artifacts, such as the artificial parcel inclination, caused by sequential computation. A generalized 20 coupled Markov chain (GCMC) is tested through applying a hypothetical soil map to evaluate the appropriateness as a substituting model for conventional geostatistical models. Comparing to sequential indicator model (SIS), the simulation results from GCMC shows lower entropy at the boundaries of indicators which is closer to real soil maps. For under-sampled indicators, however, GCMC under-estimates the presence of the indicators, which is a common aspect of all other geostatistical models. To improve this under-estimation, further study on data fusion (or assimilation) inclusion in the GCMC is required.

• Journal of Soil and Groundwater Environment
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• v.19 no.4
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• pp.31-44
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• 2014

In the present study, a few of recently developed geostatistical models are comparatively studied. The models are two-point statistics based sequential indicator simulation (SISIM) and generalized coupled Markov chain (GCMC), multi-point statistics single normal equation simulation (SNESIM), and object based model of FLUVSIM (fluvial simulation) that predicts structures of target object from the provided geometric information. Out of the models, SNESIM and FLUVSIM require additional information other than conditioning data such as training map and geometry, respectively, which generally claim demanding additional resources. For the comparative studies, three-dimensional fluvial reservoir model is developed considering the genetic information and the samples, as input data for the models, are acquired by mimicking realistic sampling (i.e. random sampling). For SNESIM and FLUVSIM, additional training map and the geometry data are synthesized based on the same information used for the objective model. For the comparisons of the predictabilities of the models, two different measures are employed. In the first measure, the ensemble probability maps of the models are developed from multiple realizations, which are compared in depth to the objective model. In the second measure, the developed realizations are converted to hydrogeologic properties and the groundwater flow simulation results are compared to that of the objective model. From the comparisons, it is found that the predictability of GCMC outperforms the other models in terms of the first measure. On the other hand, in terms of the second measure, the both predictabilities of GCMC and SNESIM are outstanding out of the considered models. The excellences of GCMC model in the comparisons may attribute to the incorporations of directional non-stationarity and the non-linear prediction structure. From the results, it is concluded that the various geostatistical models need to be comprehensively considered and comparatively analyzed for appropriate characterizations.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.24-29
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• 1994

To examine whether the signal sequence of Bacillus endo-1, 4-glucanase can act functionally in a yeast, a lower eucaryote, two recombinant plasmids were constructed and introduced into Saccharomyces cerevisiae: recombinant plasmid pGCMC10 containing the complete signal sequence of Bacillus endoglucanase, and pGCMC11 without the signal sequence. Secretion of endoglucanase into culture medium was obtained with the yeast transformant containing plasmid pGCMC10. The secreted endoglucanase was glycosylated and was apparently processed to be about 36 kilodaltons (KDa) and 43KDa proteins. The glycosylated endoglucanase from yeast transformant was more thermostable than the nonglycosylated endoglucanase from Escherichia coli transformant.

• Analytical Science and Technology
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• v.18 no.4
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• pp.309-319
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• 2005

The adsorption characteristics of gaseous molecules on the carbonaceous adsorbent have been investigated at various temperature and pressure with different pore sizes using Grand Canonical Monte Carlo (GCMC) simulation method. The geometrical parameters and spectroscopic properties of adsorbates have been computed using density functional theory (DFT). At higher temperatures is the adsorption amount of adsorbates is decreased due to their vaporization. Considering the pore size effect, the adsorption characteristic depends on the adsorbate size, polarity and interaction between adsorbates, etc. At all cases employed in this study, the adsorption amount of adsorbates on the carbonaceous adsorbent is increased in the order $NH_3$ < $H_2S$ < $CH_3SH$, and this result is qualitatively in good agreement with the experimental observation.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1087-1094
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• 2008

This article presents a multi-scale simulation approach starting from the molecular level for the adsorption process development, specifically, in n-hexane adsorption on activated carbon. A grand canonical Monte-Carlo(GCMC) method is used for the prediction of adsorption isotherms of n-hexane on activated carbon at the molecular level. Geometric effects and hydrodynamic properties of the adsorption column are examined by means of the two dimensional CFD(computational fluid dynamics) simulation. The adsorption isotherms from the molecular simulation and the axial diffusivity from the CFD simulation are exploited for the process simulation where the elution curve of n-hexane is obtained. For the first moment(mean residence time) of the pulse-response with respect to temperature and flowrate, the process simulation results obtained from this three-steps multiscale simulation approach show a good agreement with experimental data within 20% of maximum difference. The multi-scale simulation approach addressed in this study will be useful to accelerate the adsorption process development, while reducing the number of experiments required.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.300-309
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• 2022

This study aimed to evaluate the effects of two ginsenoside Rb1 (G-Rb1) loaded films on oral wound healing. Two types of G-Rb1 films, G-Rb1 loaded carboxymethyl cellulose (GCMC) film and G-Rb1 loaded hyaluronic acid (GHA) film, were developed. A total of 36 Sprague-Dawley rats were divided into 3 groups: control, GCMC, and GHA. After wound formation on midpalate, the control group was left without treatment, whereas the experimental groups had films attached. The specimen was analyzed clinically and histologically after 7 and 21 days. For clinical analysis, the area of incompletely re-epithelialized wound was measured. For histological analysis, the distance between the margins of the wound (soft tissue gap) was measured and the percentage of the collagen-stained area on the specimen was calculated. In clinical and soft tissue gap analysis, the GCMC group presented improved healing compared to the GHA group and the control at day 7 (p < 0.05). And, both GCMC (9.74 ± 10.12%) and GHA groups (19.50 ± 14.47%) presented greater collagen-positive pixels compared to control (0.89 ± 1.60%) at day 7 (p < 0.05). However, there were no differences in these parameters among the groups on day 21. Therefore, G-Rb1 loaded films improved oral wound healing.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.747-754
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• 2009

In this study, adsorption isotherms of o-DCB(ortho-dichlorobenzene) on an activated carbon heated at $1000^{\circ}C$ for 24 hours were obtained by experiment and were predicted by using molecular simulation. The initial molecular structure of the activated carbon was designed on the basis of its molecular formula and functional groups ratio measured experimentally. Then, the molecular structure was optimized using the COMPASS(condensed-phase optimized molecular potentials for atomistic simulation studies) force field. The particle porosity, specific surface area, and particle density obtained from the optimized molecular structure of activated carbon were compared with those experimental data. The errors between experimental data and simulation results of the particle porosity, specific surface area, and particle density were shown as 7.6, 3.8, and 2.8%, respectively. Adsorption isotherms constants of o-DCB are calculated by the GCMC(grand canonical Monte Carlo) method in the optimized molecular structure of activated carbon. The simulation result of the adsorption isotherms showed an error of under 3%, compared to that of experimental data. Adsorption isotherms, adsorption heat and pore diffusivity of 2,3,7,8-TCDD(tetrachlorodibenzo-p-dioxin) was finally obtained in the same molecular structure of the activated carbon as used for o-DCB. Thus, adsorption characteristics of persistent organic pollutants on activated carbon, which are not easy to experimentally evaluate, are predicted by the molecular simulation.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.80-85
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• 2016

본 연구에서는 Grand-Canonical Monte Carlo 시뮬레이션(GCMC)을 이용하여 서로 반대의 전하를 띤 고분자 전해질의 정전기적 특징을 이해하고, 고분자 전해질 다이오드의 메커니즘을 연구하였다. 고분자 전해질과 서로 반대의 전하를 띤 이온들의 모델은 전하를 띤 free-jointed hard chain과 hard sphere을 이용하였다. 본 연구진은 위와 같은 시뮬레이션을 통해, 평형 상태일 때의 고분자 전해질과 이온의 분포를 연구하였으며, 이 시스템에 전압을 걸어줌에 따라 이온의 이동 모습을 관찰하였다. 또한 전압의 효과와 더불어 고분자 전해질의 농도와 이온들의 크기 변화에 대해서도 연구를 진행하였다.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.484-491
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• 2019

An efficient propylene/propane separation technology is needed to obtain high-purity propylene, which is a raw material for polypropylene synthesis. Since conventional cryogenic distillation is an energy-intensive process due to the similar physicochemical properties of propylene and propane, adsorptive separation has gained considerable interest. In this study, we have computationally investigated the changes in adsorption separation performances by arbitrarily controlling the adsorption strength of open metal sites in two different types of metal-organic frameworks (MOFs). Through the evaluation of adsorptive separation performances in terms of working capacity, selectivity, and Adsorption Figure of Merit (AFM), we have suggested proper density and strength of adsorption sites as well as appropriate temperature condition to obtain optimal propylene/propane adsorptive separation performances.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.1
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• pp.59-69
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• 2003

The adsorption characteristics of H$_2$S, NH$_3$and $CH_3$SH on the graphite carbon have been investigated using Grand Canonical Monte Carlo(GCMC) method with universal force field (UFF) and dreiding force field. Most of the activated carbons used in vapor phase adsorption have the micropore of 6$\AA$ to 20$\AA$ and the specific surface area of ca. 1000 m$^2$/g, as the result of $N_2$ adsorption by BET method. For the more efficient comparison, the activated carbons have been manipulated with different pore sizes. The adsorption characteristics of H$_2$S, NH$_3$and $CH_3$SH have been considered at various temperatures and pressures. The adsorption amount using Dreiding force field is predicted to be lower than that using UFF. As the temperature is going to high, the adsorption amount of adsorbates is decreased due to their vaporization. Considering the pore size effect, the adsorption characteristic depends on the adsorbate size, polarity and interaction between adsorbates, etc. At all cases employed in this study, NH$_3$ is barely adsorbed and $CH_3$SH is preferentially adsorbed on the graphite carbon. Our theoretical result is qualitatively good agreement with the experimental observation. However, there are some quantitative discrepancies depending on the functional groups and pore size distribution on the real activated carbons used in experiment.