• Food Science and Preservation
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• v.24 no.6
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• pp.795-801
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• 2017

Aralia elata Seemann (AE) has long been used as a folk medicine for the treatment of various diseases including diabetes mellitus, anti-arthritic, and anti-gastric ulcer agent in Korea, Japan, and China. This study was performed to establish a simple and reliable HPLC/UV analytical method for determination of most active anti-hypertensive compound, a 3-O-${\alpha}$-L-rhamnopyranosyl($1{\rightarrow}$2)-${\alpha}$-L-arabinopyranosyl hederagenin 28-O-${\beta}$-D-xylopyranosyl($1{\rightarrow}6$)-${\beta}$-D-glucopyranosylester (HE) for the standardization of the shoot extract of AE as a health functional food ingredient. The quantitative analytical method of HE was optimized by HPLC analysis using reverse-phase C18 column at $40^{\circ}C$ with $H_2O$ and acetonitrile (70:30, v/v) as an isocratic mobile phase at a flow rate of 1.0 mL/min and detection wavelength of UV 205 nm. This HPLC/UV analytical method showed good specificity and high linearity in the tested range of 0.03125-2.0mg/ml with excellent coefficient of determination ($R^2$) of 0.9999. The limit of detection and limit of quantification were $12.0{\mu}g/mL$ and $36.5{\mu}g/mL$, respectively. Relative standard deviation (RSD) values of data from intra- and inter-day precision were less than 0.2% and 0.1%, respectively. These results indicate that the established HPLC/UV analytical method is very simple, specific, precise, accurate, and reproducible and thus can be useful for the quantitative analysis of HE as a functional anti-hypertensive compound in AE extract.

• YAKHAK HOEJI
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• v.51 no.2
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• pp.133-139
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• 2007

A simple and sensitive HPLC-MS method for quantitation of 10${\alpha}$-methoxy-9,10-dihydrolysergol (MDL), the main metabolite of nicergoline, in human plasma was developed and the bioavailability parameters of MDL was assessed in Korean healthy male volunteers. Clomipramine was used as an internal standard. MDL and internal standard in plasma sample were extracted using ethyl acetate. A centrifuged upper layer was then evaporated and reconstituted with mobile phase of 10 mM ammonium acetate-acetonitrile (10 : 90, v/v). The reconstituted samples were injected into a Zorbax SB-C8 column (2.1${\times}$150 mm,5 ${\mu}$m) at a flow-rate of 0.3 ml/min. Using MS with selected ion monitoring (SIM) mode, MDL and clomipramine were detected without severe interference from human plasma matrix. MDL produced a protonated molecular ion ([M+H]$^+$) at m/z 287. Internal standard produced a protonated molecular ion ([M+H]$^+$) at m/z 315. A linear relationship for MDL was found in the range of 2.5${\sim}$100 ng/ml. The lower limit of quantitation (LLOQ) was 2.5 ng/ml with acceptable precision and accuracy. The intra- and inter-day validation for all coefficients of variation (R.S.D.%) were found less than 15%. Main pharmacokinetic parameters of 30 mg of nicergoline were revealed as follows: AUC$_t$ 321.1${\pm}$64.5 ng${\cdot}$hr/ml, C$_{max}$, 51.2${\pm}$25.3 ng/ml, T$_{max}$ 3.6${\pm}$1.5 hr, K$_{el}$ 0.12${\pm}$0.07 hr$^{-1}$ and t$_{1/2}$ 7.6${\pm}$3.4 hr. Inter subject variations and race differences were shown in comparison with the published data in the literature.

• Korean Journal of Materials Research
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• v.8 no.8
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• pp.751-756
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• 1998

Effects of remote hydrogen plasma cleaning process parameters on the removal of Fe impurities on Si surfaces and the Fe removal mechanism were investigated. Fe removal efficiency is enhanced with decreasing the plasma exposure time and increasing the rf-power. The optimum plasma exposure time and rf-power are 1 min and 100W. respectively, in the range below 10 min and 100W. Fe removal efficiency is better under lower pressures than higher pressures, and the optimum $\textrm{H}_2$ flow rate was found to be 20 and 60sccm, respectively, under a low and a high pressure. The post-RHP(remote hydrogen plasma) annealing enhanced metallic contaminants removal efficiency, and the highest efficiency was achieved at $600^{\circ}C$. According to the AFM analysis results Si surface roughness was improved by 30-50%, which seems to be due to the removal of particles by the plasma cleaning. Also. Fe impurities removal mechanisms by remote hydrogen plasma are discussed.

• KSBB Journal
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• v.19 no.6 s.89
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• pp.427-432
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• 2004

The purpose of this study is to investigate the feasibility of a cosolvent-modified supercritical $CO_2\;(scCO_2)$ extraction technique for the production of licorice extracts with high levels of glabridin. The effects of various parameters such as the type and amount of modifiers, extraction temperature ($40{\sim}80^{\circ}C$) and pressure ($10{\sim}50.0\;MPa$) on the extraction efficiency were examined at a fixed flow rate of 1 mL/min. The organic solvent extraction with pure methanol was also conducted for a quantitative comparison with the $scCO_2$ extraction. The recovery of glabridin from licorice was found to be extremely small for pure $scCO_2$. However, the addition of modifiers such as ethanol and acetone to $scCO_2$ resulted in a significant improvement in the recovery of glabridin. The recovery of glabridin was observed to increase with pressure at a constant temperature. Furthermore, the purity of the glabridin obtained from the $scCO_2$ extraction was higher compared with the organic solvent extraction.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.249-257
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• 2007

The periodic square wave (PSW) model was successfully applied to the optimal design of a batch-storage network. The network structure can cover any type of batch production, distribution and inventory system, including recycle streams. Here we extend the coverage of the PSW model to multitasking semi-continuous processes as well as pure continuous and batch processes. In previous solutions obtained using the PSW model, the feedstock composition and product yield were treated as known constants. This constraint is relaxed in the present work, which treats the feedstock composition and product yield as free variables to be optimized. This modification makes it possible to deal with the pooling problem commonly encountered in oil refinery processes. Despite the greater complexity that arises when the feedstock composition and product yield are free variables, the PSW model still gives analytic lot sizing equations. The ability of the proposed method to determine the optimal plant design is demonstrated through the example of a high density polyethylene (HDPE) plant. Based on the analytical optimality results, we propose a practical process optimality measure that can be used for any kind of process. This measure facilitates direct comparison of the performance of multiple processes, and hence is a useful tool for diagnosing the status of process systems. The result that the cost of a process is proportional to the square root of average flow rate is similar to the well-known six-tenths factor rule in plant design.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.407-410
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• 2013

The chlorination of a metallurgical-grade silicon was carried out in a fluidized bed reactor, 25 mm in diameter. The flow rate of the chlorine admitted into the reactor was 0.2 L/min and that of the carrier nitrogen was 0.8~1.0 L/min. The reactor temperature was maintained at $450^{\circ}C$ and the temperature of the coolant at the $SiCl_4$ condenser was at $-5^{\circ}C$. The $SiCl_4$ yield increased with increasing the mole fraction of chlorine in the feed gas, exhibiting 28% at the mole fraction of 0.2. Further increase of the chlorine mole fraction was not attempted in a worry that the reactor might be failed due to the high exothermicity of the reaction. The production of $SiCl_4$ from silicon by fluidized bed chlorination was demonstrated on a laboratory scale, which is a stepping stone for future studies under more severe conditions toward industrial application.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.19-24
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• 2009

Formation of an adhesion/barrier layer and a seed layer by sputtering techniques followed by electroplating has been one of the most widely used methods for the filling of through-Si via (TSV) with high aspect ratio for 3-D packaging. In this research, the adhesion and diffusion-barrier properties of the $TaN_x$ film deposited by reactive sputtering were investigated. The adhesion strength between Cu film and $SiO_2$/Si substrate was quantitatively measured by $180^{\circ}$ peel test and topple test as a function of the composition of the adhesive $TaN_x$ film. As the nitrogen content increased in the adhesive $TaN_x$ film, the adhesion strength between Cu and $SiO_2$/Si substrate increased, which was attributed to the increased formation of interfacial compound layer with the nitrogen flow rate. We also examined the diffusion-barrier properties of the $TaN_x$ films against Cu diffusion and found that it was improved with increasing nitrogen content in the $TaN_x$ film up to N/Ta ratio of 1.4.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.62-73
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• 2014

This research was focused to apply response surface methodology for optimization of bio-methane production by biogas upgrading process. Methane concentration(Y1) and methane efficiency(Y2) on biogas upgrading process were mathematically described as being modeled by the use of the Box-Behnken design on response surface methodology. The results of ANOVA(analysis of variance) about models, the probability value of the methane concentration and methane recovery response surface model are 0.0001 and 0.0001, respectively and coefficient of determination($R^2$) are 0.9788 and 0.9710, respectively. The response surface model is proved of high reliability and suitability. The operation pressure had the greatest influence to methane concentration than other operation parameters and the PSA rotary valve velocity had the greatest influence to methane recovery than other operation parameters. Optimal condition of biogas upgrading process for production of $100Nm^3/hr$ bio-methane were operation pressure 8.0bar and outlet flow rate 31.55RPM, respectively. At that operation condition the methane concentration of bio-methane was 97.13% and methane recovery in biogas upgrading process was 75.89%.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.11
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• pp.89-92
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• 1993

In this article, we present and analyze the results of the three consecutive in vivo experiments of the LVAD to evaluate the function of the LVAD and the adverse effects on living animals. We applied the LVAD consecutively to three mongrel dogs and the circulation of the blood was assisted under the anesthesia. We used in general both the asynchronous mode and the synchronous mode to drive the LVAD. During the experiments we monitored the dogs with a polygraph to evaluate the function of the LVAD and the additional effects on the natural hearts. We also examined several clinical pathologic tests in order to see the effects of the LVAD to the red blood cells and the other internal organs. The dogs survived for two to there days. The LVAD assisted the circulatory system at the maximum assist flow rate of 3.0 1/min. Although the red blood cells of the dogs had mechanical damages by the LVAD to result in the hemolysis, the degree of the hemolysis was not so high and the damages caused by the hemolysis on the dogs were not serious. The myocardium of the first dog was gradually worsened and eventually failed. The damage of the myocardium was due to the asynchronous driving mode of the LVAD. The other organs did not have serious damages due to the application of the LVAD. The main purpose of this paper is to evaluate the results of the in vivo experiments of the LVAD and to find better ways to the application of the LVAD to human beings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.390-397
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• 2017

The introduction of exotic fish species may reduce the number of native fish species and disturb the aquatic ecosystem. Therefore, measures to block and manage fish species are required. Accordingly, a fish species blocking system using bubbles was developed in this study to block exotic fish species. An experimental channel was produced and the possibility of blocking such exotic fish species was evaluated. The bubble generator is a system that produces a bubble curtain by generating air with an air compressor that blocks fish species. Bluegill, which is an exotic fish species in the country, was tested with this generator. The size of bluegill was between 0.10 m and 0.15 m and the depth of water was maintained at 0.70 m. The flow velocity of the experiment channel was classified into 3 levels (0.20 m/s, 0.10 m/s, and 0.05 m/s) considering the natatorial ability of the fish species. The results revealed that 70.07% of bluegill showed movements to swim upstream before applying the bubble, but it is considered that the ascending rate would be higher given that the fish species thinks downstream is a habitat and showed almost no movement. However, when the blocking facility was installed, most fish species showed movements to return to the downstream again by the bubble curtain, indicating a very high blocking effect. In particular, when the generating bubble was terminated, the fish species swam back to the upstream area very soon, so the fish species blocking effect using the bubble was excellent.