• 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 Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.4
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• pp.79-87
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• 2011

In this paper, the best conditions for the deposition of the high quality diamond thin-film from N-hexane as a carbon source in the microwave plasma process was carried out. Major parameters are the deposition time, flow rates of oxygen and hexane. The deposition time for the steady state thin-film was required more than 4[h], and the suitable flow rates of hexane and oxygen for the high-quality thin-film are 0.4[sccm] and 0.1~0.2[sccm], respectively. In addition, amorphous carbons such as DLC and graphite were grown by increasing the flow rate of hexane, and it decreased by increasing the flow rate of oxygen. Specifically, the growth rate is about 1.5[${\mu}mh-1$] under no addition of oxygen and it decreased about 60[%] as ca. 1.0[${\mu}mh-1$] with oxygen.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.983-989
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• 2012

The purpose of this paper is to decide the optimum synthesis conditions of polycrystalline diamond films according to the ratio of gas mixture. Diamond films were deposited with cyclo-hexane as a carbon precursor by the microwave plasma enhanced chemical vapor deposition process. The optimum oxygen ratio to cyclo-hexane was reached about 125 % under the fixed 0.3% c-hexane in hydrogen. Oxygen plays a role in etching the graphitic components of carbon sp2 bond effectively. By OES measurement, the best synthesis conditions found out about 12.5 % and 15.75 %, which is the emission intensity ratios of CH(B-X) and $H{\beta}$ on $H{\alpha}$, respectively. Also, the electron temperature was similar about 5,000 to 5,200 K in this work.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.305-308
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• 2012

In this study, we evaluated antifungal and antioxidant activities of condensed liquid of volatile organic compounds generated during the drying process of Chamaecyparis obtuse. Condensed liquid of volatile organic compounds were extracted with hexane and ethyl acetate, respectively. The extracts were used for antifungal activity at range from 100 to 500 mg/L Antifungal activity of extracts increased as the extracts concentration increased, the activity against tested dermatophytes was high at 500 mg/L. Among extract solvents, antifungal activity was higher at hexane extract than the ethyl acetate. Especially, the antifungal activity against Trichophyton rubrum was higher than other tested dermatophytes. Antioxidant activity was 90% above 25 mg/L regardless of the extractive solvents, while the hexane extract showed high antioxidant activity below 25 mg/L. Major compounds of hexane extract were torreyol, alpha-cadinol, and tau-cadinol. However, major compounds of ethyl acetate extract were alpha-amorphene, alpha-cadinol, and gamma-cadinene.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.169-174
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• 2022

In this study, a tandem water and hexane washing process was developed to improve the recovery efficiency of paclitaxel derived from Taxus chinensis. The polar impurities contained in the sample were effectively removed by washing with water at a sample/water ratio of 1:40 (w/v) for 10 min. In addition, the non-polar impurities were effectively removed by washing with hexane at a sample/hexane ratio of 1:160 (w/v) for 20 min. A high purity of paclitaxel (>30.0%) was obtained in a short operating time (~30 min) by sequential washing with water and hexane.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.41-50
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• 2005

For the removal of residual pesticides in ginseng extracts, we estabilished the removal process using pilot plant system, the characteristic components of ginseng maintains only. According to the agricultural chemical removal process, we monitored residual pesticides of 155 species, compraing the characteristic components of ginseng. The process of 4 types of agricultural chemical removal process compared to the control test was appeared that the residual pesticides were eliminated. As results above, the most efficient method of the possibility of raising the removal ratio of the agricultural chemical construction process was dried process of hexane after dipping and also remaining quality of the hexane appeared lowly. Besides, the removal process had an effected on the ginsenocide os ginseng, only the residual pesticides will be able to remove.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.413-417
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• 2003

The last few decades have seen drastic growth in the use of brominated flame retardants(BFRs). There is the problems of polybrominated dibenzo-p-dioxins(PBDDS) and polybrominated dibenzofurans(PBDFs) generation as by-products in combustion process of BFRs. PBDDs/PBDFs are highlighted the new pollutants of environmental contamination, recently. In this study, the 10 kinds of PBDDs/PBDFs standards were used to perform the experiments of recoveries. The analysis of PBDDs/PBDFs in soil environmental samples. was carried out. In silica gel column cleanup, PBDDs/PBDFs eluted until 80mL of n-hexane, and the recovery was obtained 73∼105%. In multi-layer silica gel column cleanup, the recovery was obtained 56∼125% with various elution solvents. In alumina clean process, the standard mixture(PBDES, PBDDs/PBDFs) eluted the first fraction of 2% dichloromethane with n-hexane in the range of 0∼100mL, PBDEs compounds eluted in the second fraction of 50% dichloromethane with n-hexane. In activated carbon column cleanup, the PBBEs eluted to the first fraction(n-hexane) and second fraction(toluene), but PBDDs/PBDFs only eluted to the second fraction. The analytical methods of PBDDs/PBDFs for soil was established based on the experimental results of the environmental samples.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.383-389
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• 2010

The vapor concentration of hexane in a liquid spray jet in crossflow was qualitatively measured on the basis of the infrared (IR) extinction techniques. The objectives of the present study are to understand the whole evaporation process from droplet breakup to vapor and to confirm the usefulness of IR emission method in a lab-scale ramjet combustor. From the experimental results, we concluded that hexane vapor mole fraction increased with temperature rise and kept nearly constant during the variation of fuel to air momentum ratio.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.25-31
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• 2010

The vapor concentration of hexane in a liquid spray jet in crossflow was qualitatively measured on the basis of the infrared (IR) extinction techniques. The objectives of the present study are to understand the whole evaporation process from droplet breakup to vapor and to confirm the usefulness of IR emission method in a lab-scale ramjet combustor. From the experimental results, we concluded that hexane vapor mole fraction increased with temperature rise and kept nearly constant during the variation of fuel to air momentum ratio.

• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.61-67
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• 2009

A non-discharged system of sequentially physico-chemical water treatment was used to treat the contaminated water produced from washing system of soils according to full-scale soil washing. After washing the TPH contaminated soils, the remaining concentrations of COD$_{Mn}$, SS, and n-hexane were analyzed for each compartment to estimate the treatment efficiencies of non-discharged system. Three times of sampling events were conducted for 4 different compartments (sediment tank, flocculation tank, oil/water separator, and process-water tank). In addition, soil washing efficiencies and concentrations of each parameter (COD$_{Mn}$, SS, and n-hexane) for process-water tank were analyzed for about 8 months. As results, the average efficiency of soil washing was high to have 95.9%, regardless of the condition of TPH contamination level for soils, as well as the concentrations of COD$_{Mn}$, SS, and n-hexane in the process-water tank were below the regulation limits of the Water Environmental Conserveation Act. Accordingly, the full-scale washing treatment system in this study could make the washing water 100% recycled which lead the system to be environmentally-friendly and economical.