• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.98-98
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• 1999

Highly transparent and conducting tin-doped indium oxide (ITO) films were deposited on polycarbonate substrate by ion-assited deposition. Low substrate temperature (<10$0^{\circ}C$) was maintained during deposition to prevent the polycarbonate substrate from be deformed. The influence of ion beam energy, ion current density, and tin doping, on the structural, electrical and optical properties of deposited films was investigated. Indium oxide and tin-doped indium oxide (9 wt% SnO2) sources were evaporated with assisting ionized oxygen in high vacuum chamber at a pressure of 2$\times$10-5 torr and deposition temperature was varied from room temperature to 10$0^{\circ}C$. Oxygen gas was ionized and accelerated by cold hallow-cathode type ion gun at oxygen flow rate of 1 sccm(ml/min). Ion bea potential and ion current of oxygen ions was changed from 0 to 700 V and from 0.54 to 1.62 $\mu$A. The change of microstructure of deposited films was examined by XRD and SEM. The electrical resistivity and optical transmittance were measured by four-point porbe and conventional spectrophotometer. From the results of spectrophotometer, both the refractive index and the extinction coefficient were derived.

• Korean Journal of Medicinal Crop Science
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• v.9 no.1
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• pp.21-25
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• 2001

Major saponins in ginseng were analysed using reverse phase high performance liquid chromatography with binary mobile phase gradient control system instead of normal phase column. The optimum condition were as following : reverse phase column; ${\mu}{\beta}ondapak\;C_{18}$ column (Waters, $3.9mm{\times}300\;mm,\;5{\mu}m$), methyl cyanaide/water binary mobile phase gradient control system, solvent flow rate; 1.5 ml/min, and UV($203{\mu}m$ ) detector. The complete separation of ginsenoside $Rb_1,\;Rb_2,\;Rc,\;Rd,\;Re,\;Rf\;and\;Rg_1$ was achieved within 55 min. The Regression coefficients of the calibration curves for seven ginsenosides were 0.99.

• Journal of the Korean institute of surface engineering
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• v.38 no.5
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• pp.188-192
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• 2005

Indium zinc oxide (IZO) thin films were deposited on glass substrate by dc magnetron sputtering. The effects of oxygen flow rate and deposition temperature on electrical and optical properties of the films were investigated. With addition of small amount of oxygen gas, the characteristic properties of amorphous IZO films were improved and the specific resistivity was about $4.8{\times}10^{-4}\Omega{\cdot}cm$. Change of structural properties according to the deposition temperature was observed with XRD, SEM, and AFM. Films deposited above $300^{\circ}C$ were found to be polycrystalline. Surface roughness of the films was increased due to the formation of grains on the surface. Electrical conductivity became deteriorated for polycrystalline IZO films. Consequently, high quality IZO films could be prepared by do sputtering with $O_{2}/Ar{\simeq}0.03$ and deposition temperature in range of $150\~200^{\circ}C$; a specific resistivity of $3.4{\times}10^{-4}{\Omega}{\cdot}cm$, an optical transmission over $90\%$ at wavelength of 550 nm, and a rms value of surface roughness about $3{\AA}$.

• The Journal of Korean Medicine
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• v.25 no.3
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• pp.45-54
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• 2004

Objectives : This study was aimed to evaluate marker substances in Gami-Honghwa-Tang (KH-19) by high performance liquid chromatography-photodiode array detector (HPLC-DAD). Gami-Honghwa-Tang is composed of nine crude herbs, Rehmanniae Radix Preparata, Angelicae Gigantis Radix, Cnidii Rhizoma, Paeoniae Radix, Corni Fructus, Moutan Cortex Radicis, Lycii Fructus, Carthami Flos and Glycyrrhizae Radix. Methods : The separation was performed on an Aquasil C18 (4.6×250mm) column by gradient elution with 0.05% TFA in H2O - 0.05% TFA in acetonitrile (0 min 100:0, 20 min 90:10, 40 min 70:30, 60 min 50:50, 80 min 0:100, 90 min 100:0) as the mobile phase at a flow-rate of 1.0 ml/min with detection at 190-800nm. Also we examined the contents for bacteria, pesticide residue and harmful heavy metals. Results : HPLC-DAD was employed to determine the quantities and the qualities of several marker substances such as 5­hydroxymethyl-2-furaldehyde (5-HMF), paeonol, loganin, paeoniflorin, glycyrrhizin, and decursin in the KH-19. There were no bacterial contents, pesticide residues, or harmful heavy metals. Conclusions : We suggest these results could be a useful evidence for quality control of KH-19. This method permits fingerprints of selected individual marker substances from herbal prescriptions without derivatization, multiple purification steps, or lengthy separation times.

• Journal of Pharmaceutical Investigation
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• v.38 no.1
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• pp.57-61
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• 2008

A HPLC-ELSD method was developed to determine saikosaponin derivatives from Bupleuri Radix. Eight saikosaponins, saikosaponin c, i, h, a, $b_2$, g, $b_1$ and d, were analyzed under optimized HPLC conditions [column: Eclipse XDB $C_{18}$ ($150{\times}4.6mm$ i.d., $5{\mu}m$; mobile phase: $H_2O$ with 0.1% $CH_3$COOH (v/v) for solvent A and AcCN with 0.1% $CH_3$COOH (v/v) for solvent B, gradient elution; flow rate: 1mL/min; injection volume: $20{\mu}L$]. Good linearity was achieved in the range from 62.5 to $250{\mu}g/mL$ for each compound, and intra-day precision and accuracy at each concentration level varied between 0.05 and 5.45% and between 93.9 and 109.6%, respectively, whereas those for inter-day variations were between 0.91 to 2.73% and 94.3 to 106.1%. This HPLC-ELSD method was applied for the determination of sakosaponins from Bupleuri Radix samples, and saikosaponin a $(0.79{\pm}0.20mg/g)$, c $(0.33{\pm}0.06mg/g)$ and d $(0.48{\pm}0.15mg/g)$ were observed as major compounds. The other saikosaponins were shown under limit of quantification level thus couldn't be quantified. The present study suggested that the introduced HPLC-ELSD method is selective and reliable, and not only saikosaponin a, but also saikosaponin c and d should be employed as the standard markers for Bupleuri Radix.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.2
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• pp.35-39
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• 2014

One-way degassing valves are designed to allow pressure to be released from an air-tight package while preventing air from getting back into the package. Air, especially the oxygen ($O_2$) portion of air, can have negative effects on the package contents and its freshness. The most common application of the one-way degassing valve is for fresh roasted coffee. Demands of one-way degassing valves have been increasing with the high growth of global coffee market. In this study, we have developed one-way degassing valves for coffee and food packaging using ring type rubber disk, named SP valve. Its quality and performance was verified with test results to be equal with that of global top maker's product, Goglio valve. SP valves showed 820~1200 Pa of opening pressure, 10~50 Pa of closing pressure, 1.2~1.6 L/ min of flow rate. And, the SP valve applicable to ferment food packaging is expected to contribute to globalize Korean traditional food.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.1
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• pp.85-90
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• 2010

Several studies have demonstrated that ginseng-berry extract has several beneficial properties, including anti-inflammatory, antioxidant, and vasodilation properties. Ginseng-berry extract has also been shown to have the great potential against skin aging. Its beneficial mechanism against skin aging, however, has not been examined in detail. Also, the effects of ginseng-berry extract on microcirculation and skin cellular responses have not been investigated. Inhibition of skin microcirculation is the primary cause of many adverse biological effects, which is responsible for the skin aging and darkening. We investigated the beneficial effects of ginseng-berry extract on blood circulation, transcutaneous oxygen pressure in vivo model and also on skin microcirculation, cellular response and skin brightening effect in clinical trial. We found that oral administration of ginseng-berry extract markedly increased blood flow rate and transcutaneous $O_2$ pressure, but decreased transcutaneous $CO_2$ pressure. Also, it improved skin tone on cheeks, as is skin brighteness. These results suggest that ginseng-berry extract is a potent candidate for the treatment of skin aging and brightening by improving skin microcirculation.

• Korean Journal of Veterinary Service
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• v.36 no.4
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• pp.303-309
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• 2013

This study was conducted to determine the content of 7 mycotoxins (aflatoxin $B_1$, $B_2$, $G_1$, $G_2$, $M_1$, ochratoxin A and zearalenone) using LC-MS/MS in pork available on the Korean markets. The analysis was carried out using following conditions; C18 column ($2.1{\times}100mm$, $1.7{\mu}m$), mobile phase composed of $H_2O$ (0.1 mM $NH_4Ac$ 0.01% HCOOH) : Methanol (0.1 mM $NH_4Ac$ 0.01% HCOOH), binary pump at a flow rate of 0.5 mL/min and $2{\mu}L$ of injection volume, MS/MS detector with ESI positive and negative mode. The quantication of mycotoxins was based on matrix-matched calibration curves with a correlation coefficient in excess of 0.99 for the 7 mycotoxins. The dectection limits were ranged 0.74~2.13 ng/g, with mean recoveries between 73.10~97.46% except aflatoxin $B_1$ (61.31%). We also monitored mycotoxin residues in 208 pork samples. The test results, mycotoxins were not found except one sample. Ochratoxin A in one sample of the test samples was detected below the quantification limit.

• Journal of Mushroom
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• v.11 no.2
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• pp.107-110
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• 2013

This study was carried out to optimize the conditions for a chemotaxonomic classification of Ganoderma species. The mycelia of Ganoderma species were extracted with 100% MeOH, and the concentrated extracts were further purified and partitioned with column chromatography (HP20) and n-BuOH, respectively. From the result of high-performance liquid chromatography (HPLC), the constituents of the samples were efficiently separated with a Chemco Pak $C_{18}$ column ($250mm{\times}4.6mm$) by linear gradient elution using water and acetonitrile as mobile phase components at a flow rate of 0.8 ml/min and detector wavelength at 210 nm. However, the samples without purification or partition were not detected the characteristic peaks. This profile could be used to classify and identify the various Ganoderma species.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.328-329
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• 2012

$SF_6$ gas는 반도체 및 디스플레이 제조공정 중 Dry etch과정에서 널리 사용되는 gas로 자연적으로 존재하는 것이 아닌 사용 목적에 맞춰 인위적으로 제조된 gas이다. 디스플레이 산업에서 $SF_6$ gas가 사용되는 Dry etch 공정은 주로 ${\alpha}$-Si, $Si_3N_4$ 등 Si계열의 박막을 etch하는데 사용된다. 이러한 Si 계열의 박막을 식각하기 위해서는 fluorine, Chlorine 등이 사용된다. fluorine계열의 gas로는 $SF_6$ gas가 대표적이다. 하지만 $SF_6$ gas는 대표적인 온실가스로 지구 온난화의 주범으로 주목받고 있다. 세계적으로 온실가스의 규제에 대한 움직임이 활발하고, 대한민국은 2020년까지 온실가스 감축목표를 '배출전망치(BAU)대비 30% 감축으로' 발표하였다. 따라서 디스플레이 및 반도체 공정에는 GWP (Global warming Potential)에 적용 가능한 대체 가스의 연구가 필요한 상황이다. 온실가스인 $SF_6$를 대체하기 위한 방법으로 GWP가 낮은 $C_3F_6$가스를 이용하여 $Si_3N_4$를 Dry etching 방법인 RIE (Reactive Ion Etching)공정을 한 후 배출되는 가스를 측정하였다. 4인치 P-type 웨이퍼 위에 PECVD (Plasma Enhanced Chemical Vapor Deposition)장비를 이용하여 $Si_3N_4$를 200 nm 증착하였고, Photolithography공정을 통해 Patterning을 한 후 RIE공정을 수행하였다. RIE는 Power : 300 W, Flow rate : 30 sccm, Time : 15 min, Temperature : $15^{\circ}C$, Pressure : Open과 같은 조건으로 공정을 수행하였다. 그리고 SEM (Scanning Electron Microscope)장비를 이용하여 Etching된 단면을 관찰하여 단차를 확인하였다. 또한 Etching 전후 배출가스를 포집하여 GC-MS (Gas Chromatograph-Mass Spectrophotometry)를 측정 및 비교하였다. Etching 전의 경우에는 $N_2$, $O_2$ 등의 가스가 검출되었고, $C_3F_6$ 가스를 이용해 etching 한 후의 경우에는 $C_3F_6$ 계열의 가스가 검출되었다.