• Journal of Korea Water Resources Association
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• v.39 no.11 s.172
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• pp.905-914
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• 2006

For an accurate rainfall-runoff simulation in the river basin, not evaluation of runoff model but accurate runoff data are very important. In this study, SSARR model was applied to the Geum River basin and these results are compared with runoff data observed at the Gongju gauging station. The model results didn't good fit the discharge data determined from the rating curve at Gongju gauging station during normal and dry season, especially. For the reliability analysis for the existing rating curve, we observed new stream discharge set from 2003 to 2005. We also estimated long term runoff data from the base flow separation method and defined the hydraulic characteristics. The results show that the new observed stream discharge is similar to the rainfall-runoff model results but existing rating curve seems to be overestimated about 10-20% during normal and dry season. We found that the continuous monitoring and update for the existing rating curve at the gaging station are needed for accurate estimation of runoff data.

• Archives of Pharmacal Research
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• v.24 no.3
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• pp.207-210
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• 2001

A fully automated high performance liquid chromatography with column-switching was developed for the simultaneous determination of KR60436, a new reversible proton pump inhibitor, and its active metabolite O-Demethyl-KR60436 from rat plasma samples. Plasma sample (50$\mu$l) was directly introduced onto a Capcell Pak MF Ph-1 column ($10{\times}4$ mm I.D.) where primary separation was occurred to remove proteins and concentrate target Substances Using acetonitrile-Potassium Phosphate (PH 7, 0.1 M) (2 : 8, v/v). The drug molecules eluted from MF Ph-1 column were focused in an intermediate column ($10{\times}2$ I.D.) by the valve switching step. The substances enriched in intermediate column were eluted and separated on a Vydac 218MR53 column ($250{\times}3.2$ I.D.) using acetonitrilepotassium phosphate (pH 7, 0.02 M) (47:53, v/v) at a flow rate of 0.5 ml/min when the valve status was switched back to A position. The method showed excellent sensitivity (detection limit of 2 ng/ml) with small volume of samples ($50{\mu}$l), good precision and accuracy, and speed (total analysis time 24 min) without any loss in chromatographic efficiency. The response was linear ($r^2{\geq}0.797$) over the concentration range of 5-500 ng/ml.

• Membrane Journal
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• v.11 no.3
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• pp.124-132
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• 2001

Silica membranes were prepared on a porous ${\alpha}$-alumina tube with pore size of 150nm by sol-gel and chemical vapor deposition(CVD) method for hydrogen separation at high temperatures. Silica and ${\gamma}$-lumina membranes formed by the sol-gel method possessed a large amount of mesopores of a Knudsen diffusion regime. In order to improve the $H_2$ selectivity, silica was deposited in the sol-gel derived silica/${\gamma}$-alumina layer by thermal decomposition of tetraethyl orthosilicate(TEOS) at $600^{\circ}C$. The CVD with forced cross flow through the porous wall of the support was very effective in plugging mesopores that were left unplugged in the membranes. The CVD modified silica/alumina composite membrane completely rejected nitrogen permeation and thus showed a high $H_2$ selectivity by molecular sieve effect. the permeation of hydrogen was explained by activated diffusion and the activation energy was 9.52kJ/mol.

• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.95-101
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• 2016

For a natural gas steam reforming, comparative studies of the performance in a conventional packed-bed reactor and a membrane reactor, a new conceptual reactor consisting of a reactor with series of hydrogen separation membranes, have been performed. Based on experimental kinetics reported by Xu and Froment, a process simulation model was developed with Aspen $HYSYS^{(R)}$, a commercial process simulator, and effects of various operating conditions like temperature, $H_2$ permeance, and Ar sweep gas flow rate on the performance in a membrane reactor were investigated in terms of reactant conversion and $H_2$ yield enhancement showing improved $H_2$ yield and methane conversion in a membrane reactor. In addition, a preliminary cost estimation focusing on natural gas consumption to supply heat required for the system was carried out and feasibility of possible cost savings in a membrane reactor was assessed with a cost saving of 10.94% in a membrane reactor.

• Korean Journal of Oriental Medicine
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• v.16 no.1
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• pp.173-178
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• 2010

The purpose of this study was investigation of quantitative analysis of marker substances in solid fermented Angelicae Gigantis Radix by High performance liquid chromatography(HPLC). HPLC was performed for determination of nodakenin and decursin in solid fermented Angelicae Gigantis Radix extract, the separation method was performed on C18 column ($250\;mm\;{\times}\;4.6\;mm$, $5\;{\mu}m$, RS tech) using gradient solvent mixtures of water-acetonitrile with photodiode array detector (330 nm). The flow rate was 1.0 ml/min. Retention time of nodakenin and decursin was about 11.47, 46.79 min and linearity of calibration was showed good result(r2=0.9999, 0.9999), respectively. Content of nodakenin was $0.76\;{\pm}\;0.02%$ in control, $0.31\;{\pm}\;0.00%$ in Angelicae Gigantis Radix extract fermented with Paecilomyces japonica(SDT)(p<0.01), $0.51\;{\pm}\;0.02%$ in Angelicae Gigantis Radix extract fermented with Ganoderma lucidum(SYT)(p<0.01), $0.82\;{\pm}\;0.03%$ in Angelicae Gigantis Radix extract fermented with honey(SST)(p<0.05) and $0.88\;{\pm}\;0.01%$ in Angelicae Gigantis Radix extract fermented with Nuruk(SNT)(p<0.01). Content of decursin was $4.50\;{\pm}\;0.08%$ in control, $2.90\;{\pm}\;0.05%$ in Angelicae Gigantis Radix extract fermented with Paecilomyces japonica(SDT)(p<0.01), $2.65\;{\pm}\;0.08%$ in Angelicae Gigantis Radix extract fermented with Ganoderma lucidum(SYT)(p<0.01), $4.46\;{\pm}\;0.11%$ in Angelicae Gigantis Radix extract fermented with honey(SST) and $4.73\;{\pm}\;0.04%$ in Angelicae Gigantis Radix extract fermented with Nuruk(SNT)(p<0.05), respectively.

• The Korean Journal of Food & Health Convergence
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• v.6 no.5
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• pp.19-25
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• 2020

The purpose of this study was to research and develop a step-type chemical liquid deodorizer including a liquid catalyst that can prevent civil complaints due to odor due to its excellent deodorizing performance. The main composition of chemical liquid deodorizer including liquid catalyst is cleaning deodorization, catalyst deodorization, chemical deodorization, water film plate, deodorization water circulation device, deodorization water injection device, catalyst management system, gas-liquid separation device, chemical supply device, deodorizer control panel, etc. It consists of a device. The air flow of the step-type liquid catalyst chemical liquid deodorizer is a technology that firstly removes basic odor substances, and the liquid catalyst installed in the subsequent process stably removes sulfur compounds, which are acidic odor substances, to discharge clean air. The efficiency of treating the complex odor of the prototype was 98.5% for the first and 99.6% for the second, achieving the target of 95%. The hydrogen sulfide treatment efficiency of the prototype was 100% for the first and 99.9% for the second, which achieved 95%, which was the target of the project. As a result, ammonia was removed by the reaction of ammonia and hydrogen sulfide.

• Natural Product Sciences
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• v.22 no.2
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• pp.93-101
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• 2016

For efficient quality control of the Samryeongbaekchul-san decoction, a powerful and accurate an ultra-performance liquid chromatography (UPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry (MS) method was developed for quantitative analysis of the thirteen constituents: allantoin (1), spinosin (2), liquiritin (3), ginsenoside Rg1 (4), liquiritigenin (5), platycodin D2 (6), platycodin D (7), ginsenoside Rb1 (8), glycyrrhizin (9), 6-gingerol (10), atractylenolide III (11), atractylenolide II (12), and atractylenolide I (13). Separation of the compounds 1 - 13 was performed on a UPLC BEH $C_{18}$ column ($2.1{\times}100mm$, $1.7{\mu}m$) at a column temperature of $40^{\circ}C$ with a gradient solvent system of 0.1% (v/v) formic acid aqueous-acetonitrile. The flow rate and injection volume were 0.3 mL/min and $2.0{\mu}L$. Calibration curves of all compounds were showed good linearity with values of the correlation coefficient ${\geq}0.9920$ within the test ranges. The values of limits of detection and quantification for all analytes were 0.04 - 4.53 ng/mL and 0.13 - 13.60 ng/mL. The result of an experiment, compounds 2, 6, 12, and 13 were not detected while compounds 1, 3 - 5, and 7 - 11 were detected with 1,570.42, 5,239.85, 299.35, 318.88, 562.27, 340.87, 12,253.69, 73.80, and $115.01{\mu}g/g$, respectively.

• Korean Journal of Pharmacognosy
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• v.45 no.3
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• pp.200-208
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• 2014

In this study, we performed quantification determination of four major components including aurantio-obtusin, emodin, chrysophanol, and physcion in the 70% ethanol extracts of non-processed Cassiae Semen and processed Cassiae Semen using a high-performance liquid chromatography coupled with photodiode array detector. The analytical column for separation of the 4 constituents used a Gemini $C_{18}$ column kept at $40^{\circ}C$ by the gradient elution with 1.0% (v/v) acetic acid in water and 1.0% (v/v) acetic acid in acetonitrile as mobile phase. The flow rate was 1.0 mL/min and the injection volume was $10{\mu}L$. The amount of aurantio-obtusin, emodin, chrysophanol, and physcion in non-processed Cassiae Semen were 0.07%, 0.02%, 0.25%, and 0.10%, respectively. The amount of aurantio-obtusin, emodin, chrysophanol, and physcion in processed Cassiae Semen were 0.04-0.14%, 0.01-0.03%, 0.02-0.42%, and 0.01-0.24%, respectively. Consequently, the optimal processing condition of Cassiae Semen for the improvements of amounts of four anthraquinone compounds was obtained by roasting at $240^{\circ}C$ for 15 min.

• Journal of the Korean Vacuum Society
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• v.9 no.3
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• pp.221-226
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• 2000

After manufacturing the electrochromic device (structure: ITO glass/$WO_3$/electrolyte/$V_2O_5$/ITO;glass) by using of sol-gel process and evaporation, optical properties and migration effect were investigated. The result shows that electrochromic device with heat treated (at water vapor ambient, $500^{\circ}C$, 1 hour) sol-gel coated $WO_3$ and $V_2O_5$ films had the highest transmittance variance. Electrochromic devices are based on the reversible insertion of guest atoms into structure of the host solid. But after cyclic operation, we find that the tungsten in $WO_3$ film and the indium in ITO film were migrated with each other. For the purpose of blocking migration, tungsten barrier film is inserted between ITO and $WO_3$ film. The result of cyclic voltamogram and the Auger depth profile show that the peak separation of cyclic voltamogram is reduced to below 1/10 and we could effectively block the indium and tungsten migration that is caused by flow of Li ions.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.577-582
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• 2012

In this work, vibrational circular dichroism (VCD) technique was applied for the determination of %EE of chiral compounds. It may provide an easy way to determine the %EE with a proper accuracy within 2% error ranges as well as the absolute configuration of enantiomers. We demonstrated herein a flow cell VCD (FT-VCD) technique for time-dependent %EE measurements. The simultaneous monitoring of the mole fraction and %EE for two chiral species (epichlorohydrin and glycidol mixture) in the mixture was shown to be successful without any further separation steps. Thus, we demonstrate that FT-VCD is an appropriate analytical tool to monitor the kinetics of reactions involving chiral molecules. FT-VCD also provides a convenient nondestructive approach for the time dependent determination of the optical purity of individual components in a reaction mixture containing chiral molecules.