• Korean Journal of Clinical Pharmacy
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• v.12 no.2
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• pp.71-75
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• 2002

This study was carried out to compare the bioavailability of $Ceclex^{(R)}$ (test drug, cefaclor 250 mg/capsule) with that of $Ceclor^{(R)}$ (reference drug) and to estimate the pharmacokinetic parameters of cefaclor in healthy Korean adult. The bioavailability was examined on 20 healthy volunteers who received a single dose (250 mg) of each drug in the fasting state in a randomized balanced 2-way crossover design. After dosing, blood samples were collected for a period of 6hours. Plasma concentrations of cefaclor were determined using HPLC with UV detection. The pharmacokinetic parameters $(AUC_{0-6hr},\;C_{max},\;T_{max},\;AUC_{int},\;K_e,\;t_{1/2},\;Vd)$ F, and CL/F) were calculated with non-compartmental pharmacokinetic analysis. The ANOVA test was utilized for the statistical analysis of the $T_{max},\;log-transformed\;AUC_{0-6hr}\;log-transformed\;C_{max},\;t_{l/2},\;V_d/F$, and CL/F. The ratios of geometric means of AUC0-6hr and $C_{max}$ between test drug and reference drug were $103.2\%\;(6.74\;{\mu}g{\cdot}hr/ml\;vs\;6.53{\pm}g{\cdot}hr/ml)\;and\;100.4\%\;(4.85\;{\mu}g\ml\;vs\;4.82\;{\mu}g/ml)$, respectively. The $T_{max}$ of test drug and reference drug were $0.9\pm0.38\;hr\;and\;0.83\pm0.34$ hrs, respectively. The $90\%$ confidence intervals of mean difference of logarithmic transformed $AUC_{0-6h},\;and\;C_{max}$ were log $0.98{\sim}log$ 1.08 and log $0.88{\sim}log1.15$, respectively. It shows that the bioavailability of test drug is equivalent with that of reference drug. The estimated half-life of this study was longer $(1.21\pm0.27\;hrs\;vs\;0.5-1\;hr)$, the Vd/F was larger $(68.89\pm25.72L$ vs 24.9L), and the CL/F was higher $(38.62\pm7.09\;L/hr$ vs 24.9 L/hr) than the previously reported values.

• Microbiology and Biotechnology Letters
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• v.32 no.2
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• pp.184-189
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• 2004

Rice wine cake (RWC) is the solid waste obtained after rice wine fermentation. For the mass production of the spores of yeast Saccharomyces from RWC, the optimum pretreatment condition of RWC, the optimum composition of culture medium, and the optimum culture condition were examined. For sporulation, yeast cells were grown in the pre sporulation medium (PSM), transferred into sporulation medium (SM) containing 1 % potassium acetate, and incubated in a rotary shaking incubator at $25^{\circ}C$ for 4 days. The supernatant of the mixture of RWC and water was used as the presporulation medium (PSM). The optimum temperature and time for the pre-incubation of the mixture of RWC and water (1:2) to obtain maximum sporulation yield were $V^{\circ}C$ and 24 hr, respectively, and optimum culture time in PSM was 48 hr. Using these optimum conditions, the asci number obtained was 0.72$ 1.06${\times}$10^{8}$$m\ell$. The addition of wheat coat koji into SM increased the final number of asci to beTEX>$10^{8}$ $m\ell$. Spores were formed in the SM with the initial pH of 7-11, but no spores were formed in the SM with the initial pH of 5. To save the time and effort to pretreat the RWC, 2% and 0.5% RWC without any pretreatment were directly added into PSM containing 1 % brown sugar and SM, respectively, and the maximum asci number of $1.27${\times}$10^{8}$ /$m\ell$ was obtained.

• The Korean Journal of Ceramics
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• v.4 no.2
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• pp.95-98
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• 1998

We have developed new type of superconducting-superionic conducting nanohybrids, $Ag_xI_wBi_2Sr_2Ca_{n-1}Cu_nO_y$ (n=1 and 2) by applying the chimie douce reaction to the superconducting Bi-based cuprates. These nanohybrids can be achieved by the stepwise intercalation whereby the $Ag^+$ ion is thermally diffused into the pre-intercalated iodine sublattice of $IBi_2Sr_2Ca_{n-1}Cu_nO_y$. According to the X-ray diffraction analysis, the Ag-I intercalates are found to have an unique heterostructure in which the superionic conducting Ag-I layer and the superconducting $IBi_2Sr_2Ca_{n-1}Cu_nO_y$ layer are regularly interstratified with a remarkable basal increment of ~7.3$\AA$. The systematic XAS studies demonstrate that the intercalation of Ag-I accompanies the charge transfer between host and guest, giving rise to a change in hole concentration of $CuO_2$ layer and to a slight $T_c$ change. The Ag K-edge EXAFS result reveals that the intercalated Ag-I has a $\beta$-AgI-like local structure with distorted tetrahedral symmetry, suggesting a mobile environment for the intercalated $Ag^+$ ion. In fact, from ac impedance analyses, we have found that the Ag-I intercalates possess a fast ionic conductivity ($\sigma_i=10^{-1.4}\sim 10^{-2.6}\Omega^{-1}\textrm{cm}^{-1}\;at\;270^{\circ}C$ with an uniform activation energy ($\DeltaE_a=0.22\pm 0.02$ eV). More interesting finding is that these intercalates exhibit high electronic conducting as well as ionic ones ($t_i$=0.02~0.60) due to their interstratified structure consisting of superionic conducting and superconducting layers. In this respect, these new intercalates are expected to be useful as an electrode material in various electrochemical devices.

• Food Engineering Progress
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• v.21 no.3
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• pp.225-232
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• 2017

Most of the red ginseng (RG) products contain active substances derived from hot water or alcohol extraction. Since active substances of RG are divided into two types - water-soluble and liposoluble - water or alcohol is needed as an extraction solvent and this leads the different extraction yields and components of the active substances. To overcome the limit, whole red ginseng powder can be used and consumed by consumers. In this study, the physicochemical properties and extractable active substance contents of variable-sized RG powder ($158.00{\mu}m$, $8.45{\mu}m$, and $6.33{\mu}m$) were analyzed, and dispersion stability was measured to investigate the suitable size of RG powder for industrial processing. In the results, no significant difference was found from the changes in color intensity and thiobarbutric acid tests at $4^{\circ}C$, $25^{\circ}C$, and $40^{\circ}C$ for 4 weeks. There was no significant difference on the production of antioxidants and ginsenoside among the samples (p>0.05). In dispersion stability, $RG-158.00{\mu}m$ was precipitated immediately, and the dispersion stabilities between $RG-8.45{\mu}m$ and $RG-6.33{\mu}m$ showed no significant difference. It implies that fine RG is suitable for the production process. With further study, it seemed that the physicochemical effects of RG particle sizes can be clearly revealed.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.12
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• pp.1754-1760
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• 2007

To improve poor dye uptake of safflower yellow colorants, cellulose fibers were pretreated with chitosan. The effect of chitosan pretreatment on the dyeability of safflower yellow colorants to cotton, ramie, and rayon was investigated in terms of dye uptake, color, and colorfastness. Irrespective of fiber types, dye uptake increased continuously with increase in chitosan concentration. Chitosan pretreatment improved dye uptake up to 5.6 times for cotton, 7.2 times for ramie, and 3.7 times for rayon. For cotton and ramie, the shade of dyed fabric changed YR color to Y color with increase in chitosan concentration. Dyed rayon fabrics showed Y color irrespective of chitosan concentration. Shades got darker and deeper with increasing chitosan concentration. Shades of chitosan pretreated fabrics were shifted differently depending on dyeing temperature within same fabrics. In common, the color of all dyed fabrics changed to YR at 50 and $70^{\circ}C$ while Y color at 30 and $90^{\circ}C$. V and C value decreased with increase in dyeing temperature and resulted in darker and duller color, in general. Light fastness was fair while washing fastness was poor. It was confirmed that ultrasonic dyeing method enhanced dye uptake more than 30% for cotton and ramie fabrics compared to the conventional automatic machine dyeing method. However, no difference in dye uptake between two dyeing methods was found for rayon.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.163-163
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• 2011

셀레늄(Selenium: Se) cracker cell을 이용하여 셀렌화한 $CuInSe_2$ (CIS)박막에 대해 연구한 결과를 발표하고자 한다. 화석연료의 과도한 사용으로 지구온난화라는 환경문제가 대두되면서 영구적이고 무상의 태양에너지 이용에 대한 필요성이 점차 높아지고 있다. 빛에너지를 전기에너지로 변화시키기 위한 태양전지는 재료에 따라 다양하게 개발되고 있으며 그 중 가장 주목을 받고 있는 것 중의 하나가 $CuInSe_2$을 광흡수층으로 하는 CIS 박막 태양전지이다. CIS 박막은 태양전지의 광흡수층으로 사용되는데 직접천이형 밴드구조를 가지고 있고, 약 $10^5$ $cm^{-1}$의 높은 광흡수계수를 가지고 있어 태양전지 광흡수층으로 적합한 물질로 각광받고 있다. CIS는 에너지 밴드갭이 ~1 eV로 실리콘과 유사한 밴드갭을 가지고 있으나 이는 Ga, Al을 In 대신 치환함으로 조절할 할 수 있다. 무엇보다도 sodalime 유리와 같은 저가의 기판위에 스퍼터와 같은 장치로 대면적 CIS 박막태양전지를 만들 수 있다는 것이 산업적인 면에서 장점으로 알려져 있다. 본 연구에서는 sodalime 유리기판 위에 스퍼터 방법으로 CIS 박막을 증착하고 Se cracker cell로 셀렌화하여 CIS 박막을 제조하는 것을 조사연구 하였다. 스퍼터를 이용하여 유리기판위에 Mo (Molybdenum)을 증착하고 그 위에 Cu-In-Se박막을 증착하였다. Cu-In-Se/Mo/유리기판 시료는 동일 챔버에서 Se cracker cell을 이용하여 셀렌화 처리 하였다. 물성비교를 위하여 Knudson-cell을 이용한 셀렌화도 시행하였다. Se cracker cell은 고체 Se를 가열하는 부분(R-zone)과 Se flux를 cracking 하는 부분(C-zone)으로 나누어져 있으며 C-zone은 700$^{\circ}C$로 고정하였다. 셀렌화 기판 온도는 425$^{\circ}C$로 고정하였고 Se cracker 온도는 330~375$^{\circ}C$까지 변화시켜 가며 CIS 박막을 제조하였다. 제조된 CIS 박막의 물성 조사는 사진, 현미경, SEM, EDX, XRD, Hall effects를 이용하였다. Se cracker cell로 셀렌화한 CIS 박막은 island 구조를 하고 있음을 알 수 있었다. CIS 박막의 island의 크기와 모양은 셀렌화시 R-zone 온도(Cu-In-Se 박막에 조사되는 셀레늄의 량)에 큰 영향을 받았다. 셀렌화시 셀레늄량이 적을 때는 island가 커지며 불균일해지고 셀레늄량이 많을 때 island가 작고 균일해지는 경향을 SEM을 통해 관찰할 수 있었다. X-ray 회절을 통해 셀레늄량이 적을 경우 CIS 결정이외의 결정이 박막내에 형성됨을 알 수 있었다. 학술회의에서 Se cracker cell을 이용한 셀렌화에 관한 보다 깊은 연구결과를 발표하고자 한다.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.407-412
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• 2008

As an activation procedure, in this study, the oxidation treatment of needle cokes with a dilute nitric acid and sodium chlorate $(NaClO_3)$, combined with heat treatment, was attempted. The structures of acid-treated and pyrolyzed coke were examined with XRD, FESEM, elemental analyzer, BET, and Raman spectroscopy. The behavior of double layer capacitance was investigated with the analysis of charge and discharge. The structure of needle coke treated with acid was revealed to a single phase of (001) diffraction peak after 24 h. On the other hand, thecoke oxidized by heat treatment was reduced to a graphite structure of (002) at $300^{\circ}C$. The distorted graphene layer structure, derived from the process of oxidation and reduction of the inter-layer, makes the pores by the electric field activation at the first charge, and generates the double layer capacitance from the second charge. The cell using pyrolyzed coke with 24 h acid treatment and $300^{\circ}C$ heat treatment exhibited the maximum capacitance per weight and volume of 33 F/g and 30 F/mL at the two-electrode system in the potential range of 0~2.5 V.

• Korean Journal of Materials Research
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• v.20 no.10
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• pp.501-507
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• 2010

Changes in surface morphology and roughness of dc sputtered ZnO:Al/Ag back reflectors by varying the deposition temperature and their influence on the performance of flexible silicon thin film solar cells were systematically investigated. By increasing the deposition temperature from $25^{\circ}C$ to $500^{\circ}C$, the grain size of Ag thin films increased from 100 nm to 1000 nm and the grain size distribution became irregular, which resulted in an increment of surface roughness from 6.6 nm to 46.6 nm. Even after the 100 nm thick ZnO:Al film deposition, the surface morphology and roughness of the ZnO:Al/Ag double structured back reflectors were the same as those of the Ag layers, meaning that the ZnO:Al films were deposited conformally on the Ag films without unnecessary changes in the surfacefeatures. The diffused reflectance of the back reflectors improved significantly with the increasing grain size and surface roughness of the Ag films, and in particular, an enhanced diffused reflectance in the long wavelength over 800 nm was observed in the Ag back reflectors deposited at $500^{\circ}C$, which had an irregular grain size distribution of 200-1000 nm and large surface roughness. The improved light scattering properties on the rough ZnO:Al/Ag back reflector surfaces led to an increase of light trapping in the solar cells, and this resulted in a noticeable improvement in the $J_{sc}$ values from 9.94 mA/$cm^2$ for the flat Ag back reflector at $25^{\circ}C$ to 13.36 mA/$cm^2$ for the rough one at $500^{\circ}C$. A conversion efficiency of 7.60% ($V_{oc}$ = 0.93, $J_{sc}$ = 13.36 mA/$cm^2$, FF = 61%) was achieved in the flexible silicon thin film solar cells at this moment.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.107-107
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• 2000

최근 반도체 소자의 고집적화 및 대용량화의 경향에 다라 MOSFET 소자 제작에 이동되는 게이트 산화막의 두께가 수 nm 정도까지 점점 얇아지는 추세이고 Giga-DRAM급 차세대 UNSI소자를 제작하기 위해 5nm이하의 게이트 절연막이 요구된다. 이런 절연막의 두께감소는 게이트 정전용량을 증가시켜 트랜지스터의 속도를 빠르게 하며, 동시에 저전압동작을 가능하게 하기 때문에 게이트 산화막의 두께는 MOS공정세대가 진행되어감에 따라 계속 감소할 것이다. 따라서 절연막 두께는 소자의 동작 특성을 결정하는 중요한 요소이므로 이에 대한 정확한 평가 방법의 확보는 공정 control 측면에서 필수적이다. 그러나, 절연막의 두께가 작아지면서 게이트 산화막과 crystalline siliconrksm이 계면효과가 박막의 두께에 심각한 영향을 주기 때문에 정확한 두께 계측이 어렵고 계측방법에 따라서 두께 계측의 차이가 난다. 따라서 차세대 반도체 소자의 개발 및 양산 체계를 확립하기 위해서는 산화막의 두께가 10nm보다 작은 1nm-5nm 수준의 박막 시료에 대한 두께 계측 방법이 확립이 되어야 한다. 따라서, 본 연구에서는 습식 산화 공정으로 제작된 3nm-7nm 의 게이트 절연막을 현재까지 알려진 다양한 두께 평가방법을 비교 연구하였다. 절연막을 MEIS (Medim Energy Ion Scattering), 0.015nm의 고감도를 가지는 SE (Spectroscopic Ellipsometry), XPS, 고분해능 전자현미경 (TEM)을 이용하여 측정 비교하였다. 또한 polysilicon gate를 가지는 MOS capacitor를 제작하여 소자의 Capacitance-Voltage 및 Current-Voltage를 측정하여 절연막 두께를 계산하여 가장 좋은 두께 계측 방법을 찾고자 한다.다. 마이크로스트립 링 공진기는 링의 원주길이가 전자기파 파장길이의 정수배가 되면 공진이 일어나는 구조이다. Fused quartz를 기판으로 하여 증착압력을 변수로 하여 TiO2 박막을 증착하였다. 그리고 그 위에 은 (silver)을 사용하여 링 패턴을 형성하였다. 이와 같이 공진기를 제작하여 network analyzer (HP 8510C)로 마이크로파 대역에서의 공진특서을 측정하였다. 공진특성으로부터 전체 품질계수와 유효유전율, 그리고 TiO2 박막의 품질계수를 얻어내었다. 측정결과 rutile에서 anatase로 박막의 상이 변할수록 유전율은 감소하고 유전손실은 증가하는 결과를 나타내었다.의 성장률이 둔화됨을 볼 수 있다. 또한 Silane 가스량이 적어지는 영역에서는 가스량의 감소에 의해 성장속도가 둔화됨을 볼 수 있다. 또한 Silane 가스량이 적어지는 영역에서는 가스량의 감소에 의해 성장속도가 줄어들어 성장률이 Silane가스량에 의해 지배됨을 볼 수 있다. UV-VIS spectrophotometer에 의한 비정질 SiC 박막의 투과도와 파장과의 관계에 있어 유리를 기판으로 사용했으므로 유리의투과도를 감안했으며, 유리에 대한 상대적인 비율 관계로 투과도를 나타냈었다. 또한 비저질 SiC 박막의 흡수계수는 Ellipsometry에 의해 측정된 Δ과 Ψ값을 이용하여 시뮬레이션한 결과로 비정질 SiC 박막의 두께를 이용하여 구하였다. 또한 Tauc Plot을 통해 박막의 optical band gap을 2.6~3.7eV로 조절할 수 있었다. 20$0^{\circ}C$이상으로 증가시켜도 광투과율은 큰 변화를 나타내지 않았다.부터 전분-지질복합제의 형성 촉진이 시사되었다.이것으로 인하여 호화억제에 의한 노화 방지효과가 기대되었지만 실제로 빵의 노화는 현저히 진행되었다

• Archives of Pharmacal Research
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• v.29 no.4
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• pp.328-332
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• 2006

The bioequivalence and pharmacokinetics of alendronate sodium tablets were examined by determining the plasma concentration of alendronate. Two groups, consisting of 24 healthy volunteers, each received a 70 mg reference alendronate sodium tablet and a test tablet in a $2{\times}2$ crossover study. There was a 6-day washout period between doses. The plasma alendronate concentration was monitored for 7 h after the dose, using HPLC-Fluorescence Detector (FD). The area under the plasma concentration-time curve from time 0 to the last sampling time at 7 h $(AUC_{0-7h})$ was calculated using the linear-log trapezoidal rule. The maximum plasma drug concentration $(C_{max})$ and the time to reach $C_{max}(T_{max})$ were derived from the plasma concentration-time data. Analysis of variance was performed using logarithmically transformed $AUC_{0-7h}\;and\;C_{max}$, and untransformed $T_{max}$. For the test medication versus the reference medication, the $AUC_{0-7h}\;were\;87.63{\pm}29.27\;vs.\;102.44{\pm}69.96ng\;h\;mL^{-1}$ and the $C_{max}$ values were $34.29{\pm}13.77\;vs.\;38.47{\pm}24.39ng\;mL^{-1}$ respectively. The $90\%$ confidence intervals of the mean differences of the logarithmic transformed $AUC_{0-7h}$ and $C_{max}$ values were log 0.8234-log 1.1597 and log 0.8222-log 1.1409, respectively, satisfying the bioequivalence criteria guidelines of both the US Food and Drug Administration and the Korea Food and Drug Administration. The other pharmacokinetic parameters for the test drug versus reference drug, respectively, were: $t_{1/2},\;1.87{\pm}0.62\;vs.\;1.77{\pm}0.54\;h;\;V/F,\;2061.30{\pm}986.49\;vs.\;2576.45{\pm}1826.05\;L;\;CL/F,\;835.32{\pm}357.35\;vs.\;889.48{\pm}485.87\;L\;h^{-1}; K_{el},\;0.42{\pm}0.14\;vs.\;0.40{\pm}0.18\;h^{-1};\;Ka,\;4.46{\pm}3.63\;vs.\;3.80{\pm}3.64\;h^{-1};\;and\;T_{lag},\;0.19{\pm}0.09\;vs.\;0.18{\pm}0.06\;h$. These results indicated that two alendronate formulations(70-mg alendronate sodium) were biologically equivalent and can be prescribed interchangeably.