• 한국재료학회지
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• 제15권3호
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• pp.149-154
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• 2005

Teflon like fluorocarbon thin films have been deposited on silicon and oxide molds as an antistiction layer for the hot embossing process by an inductively coupled plasma (ICP) chemical vapor deposition (CVD) method. The process was performed at $C_4F_8$ gas flow rate of 2 sccm and 30 W of plasma power as a function of substrate temperature. The thickness of film was measured by a spectroscopic ellipsometry. These films were left in a vacuum oven of 100, 200 and $300^{\circ}C$ for a week. The change of film thickness, contact angle and adhesion and friction force was measured before and after the thermal test. No degradation of film was observed when films were treated at $100^{\circ}C$. The heat treatment of films at 200 and $300^{\circ}C$ caused the reduction of contact angles and film thickness in both silicon and oxide samples. Higher adhesion and friction forces of films were also measured on films treated at higher temperatures than $100^{\circ}C$. No differences on film properties were found when films were deposited on either silicon or oxide. A 100 nm silicon template with 1 to $500\;{\mu}m$ patterns was used for the hot embossing process on $4.5\;{\mu}m$ thick PMMA spun coated silicon wafers. The antistiction layer of 10 nm was deposited on the silicon mold. No stiction or damages were found on PMMA surfaces even after 30 times of hot embossing at $200^{\circ}C$ and 10 kN.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3275-3279
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• 2014

A mass balance method for purity assessment of thermolabile organic reference materials was established by combining several techniques, including liquid chromatography with UV/VIS detector (LC-UV), Karl-Fischer (K-F) Coulometry, and thermal gravimetric analysis (TGA). This method was applied to three fluoroquinolones like enrofloxacin, norfloxacin and ciprofloxacin. LC-UV was used to analyze structurally related organic impurities based on UV/VIS absorbance spectra obtained in combination with LC separation. For all three organic reference materials, the UV/VIS spectra of the separated impurities were similar to that of the major component of the corresponding materials. This indicates that the impurities are structurally related to the respective reference material sharing common chromophores. Impurities could be quantified by comparing their absorbances at the wavelength of maximum absorbance (${\lambda}_{max}$). The water contents of the reference materials were measured by K-F Coulometry by an oven-drying method. The total inorganic impurities contents were assayed from ash residues in TGA analysis with using air as a reagent gas. The final purities estimated from results of those analytical techniques were assigned as ($99.91{\pm}0.06$), ($97.09{\pm}0.17$) and ($91.85{\pm}0.17$)% (kg/kg) for enrofloxacin, norfloxacin and ciprofloxacin, respectively. The assigned final purities would be applied to the reference materials which will be used as calibrators for the certification of those compounds in matrix CRMs as starting points for the traceability of their certified values to SI units.

• 한국관광식음료학회:학술대회논문집
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• 한국관광식음료학회 2002년도 학술논문발표회
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• pp.112-122
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• 2002

본 연구는 Egg yolk을 저온 세균(62.5$^{\circ}C$에서 4분)과 고온 세균(95$^{\circ}C$에서 30초) 하여 7$0^{\circ}C$-75$^{\circ}C$ Double bath pen에서 Hot sabayon cream으로 하여 Hot Clarified Olive oil을 서서히 첨가하며 Emulsify하여 유화한 다음 Extract spices 첨가하여 유화제품의 색도 차이를 분석하여 품질을 평가하였으며, 제조된 유화난황의 관능검사를 실시하였다. Extract spices는 A군과 B.군으로 하였으며, A.군은 Garlic을 제외한 Extract였고 B.군은 Garlic을 첨가하였다. 결과는 Figure 1-5.과 같이 나타났다. \circled1 Sabayon Cream 관능검사 결과는 노랑자위 향이 감소 되었다. \circled2 Clarified Olive 관능검사 결과는 olive oily 향이 감소되고 고소한 맛이 났다. \circled3 Sabayon과 Clarified olive oil과의 Emulsified 관능검사 결과는 부드러워 졌다. \circled4 Extract Spices A.시료의 Hot Emulsified 관능검사 결과는 oily 하였다. \circled5 Extract Spices B.시료의 Hot Emulsified 관능검사 결과는 마늘의 향이 전체적 향을 부드럽게 하였으며, 전체적인 맛은 결정적으로 우수하였다. 즉 마늘 향이 첨가된 B시료가 효과와 특성이 있었다.

• 한국재료학회지
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• 제23권4호
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• pp.246-249
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• 2013

Nano-sized ${\beta}$-SiC nanoparticles were synthesized combined with a sol-gel process and a carbothermal process. TEOS and carbon black were used as starting materials for the silicon source and carbon source, respectively. $SiO_2$ nanoparticles were synthesized using a sol-gel technique (Stober process) combined with hydrolysis and condensation. The size of the particles could be controlled by manipulating the relative rates of the hydrolysis and condensation reactions of tetraethyl orthosilicate (TEOS) within the micro-emulsion. The average particle size and morphology of synthesized silicon dioxide was about 100nm and spherical, respectively. The average particles size and morphology of the used carbon black powders was about 20nm and spherical, respectively. The molar ratio of silicon dioxide and carbon black was fixed to 1:3 in the preparation of each combination. $SiO_2$ and carbon black powders were mixed in ethanol and ball-milled for 12 h. After mixing, the slurries were dried at $80^{\circ}C$ in an oven. The dried powder mixtures were placed in alumina crucibles and synthesized in a tube furnace at $1400{\sim}1500^{\circ}C$ for 4 h with a heating rate of $10^{\circ}C$/min under flowing Ar gas (160 cc/min) and furnace cooling down to room temperature. SiC nanoparticles were characterized by XRD, TEM, and SAED. The XRD results showed that high purity beta silicon carbide with excellent crystallinity was synthesized. TEM revealed that the powders are spherical shape nanoparticles with diameters ranging from 15 to 30 nm with a narrow distribution.

• Journal of the Korean Wood Science and Technology
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• 제43권4호
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• pp.429-437
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• 2015

아세틸화처리는 목재의 치수안정성을 높이는 방법으로 알려졌다. 기상처리보다는 액상처리가 중량증가율이 높기 때문에 더 많이 사용된다. 국내산 소나무재와 잣나무재를 액상 아세틸화처리하여 밀도, 휨강도, 치수안정성 등 물리적 성질에 미치는 효과를 조사하였다. 아세틸화처리에 의한 소나무와 잣나무 시편의 중량은 각각 평균 10.4%와 9.2% 증가하였으며, 전건밀도는 각각 평균 6.9%와 4.6% 증가하였다. 소나무와 잣나무 모두 휨파괴계수(MOR)와 휨탄성계수(MOE), 동탄성계수(DMOE)의 변화는 없었다. 아세틸화처리 후 목재시료의 평균 항흡습률(PRH)은 소나무와 잣나무가 각각 20.6%와 13.8% 이었다. 평균 항흡수율(PRA)은 소나무와 잣나무가 각각 20.0%와 8.5%였다. 따라서 아세틸화처리에 의해 소나무의 치수안정성이 향상된 결과를 얻었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.423-423
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• 2011

Zinc oxide is metal oxide semiconductor with the 3.37 eV bandgap energy. Zinc oxide is very attractive materials for many application fields. Zinc Oxide has many advantages such as high conductivity and good transmittance in visible region. Also it is cheaper than other semiconductor materials such as indium tin oxide (ITO). Therefore, ZnO is alternative material for ITO. ZnO is attracting attention for its application to transparent conductive oxide (TCO) films, surface acoustic wave (SAW), films bulk acoustic resonator (FBAR), piezoelectric materials, gas-sensing, solar cells and photocatalyst. In this study, we synthesized ZnO nanoparticles and defined their physical and chemical properties. Also we studied about the application of ZnO nanoparticles as a photocatalyst and try to find a enhancement photocatalytic activity of ZnO nanorticles.. We synthesized ZnO nanoparticles using spray-pyrolysis method and defined the physical and optical properties of ZnO nanoparticles in experiment I. When the ZnO are exposed to UV light, reduction and oxidation (REDOX) reaction will occur on the ZnO surface and generate O2- and OH radicals. These powerful oxidizing agents are proven to be effective in decomposition of the harmful organic materials and convert them into CO2 and H2O. Therefore, we investigated that the photocatalytic activity was increased through the surface modification of synthesized ZnO nanoparticles. In experiment II, we studied on the stability of ZnO nanoparticles in water. It is well known that ZnO is unstable in water in comparison with TiO2. Zn(OH)2 was formed at the ZnO surface and ZnO become inactive as a photocatalyst when ZnO is present in the solution. Therefore, we prepared synthesized ZnO nanoparticles that were immersed in the water and dried in the oven. After that, we measured photocatalytic activities of prepared samples and find the cause of their photocatalytic activity changes.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.531-538
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• 2013

A mass balance method established in this laboratory was applied to determine the purity of an endosulfan-II pure substance. Gas chromatography-flame ionization detector (GC-FID) was used to measure organic impurities. Total of 10 structurally related organic impurities were detected by GC-FID in the material. Water content was determined to be 0.187% by Karl-Fischer (K-F) coulometry with an oven-drying method. Non-volatile residual impurities was not detected by Thermal gravimetric analysis (TGA) within the detection limit of 0.04% (0.7 ${\mu}g$ in absolute amount). Residual solvents within the substance were determined to be 0.007% in the Endosulfan-II pure substance by running GC-FID after dissolving it with two solvents. The purity of the endosulfan-II was finally assigned to be ($99.17{\pm}0.14$)%. Details of the mass balance method including interpretation and evaluating uncertainties of results from each individual methods and the finally assayed purity were also described.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.54-54
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• 2010

Zinc oxide is metal oxide semiconductor with the 3.37 eV bandgap energy. Zinc oxide is very attractive materials for many application fields. Zinc Oxide has many advantages such as high conductivity and good transmittance in visible region. Also it is cheaper than other semiconductor materials such as indium tin oxide (ITO). Therefore, ZnO is alternative material for ITO. ZnO is attracting attention for its application to transparent conductive oxide (TCO) films, surface acoustic wave (SAW), films bulk acoustic resonator (FBAR), piezoelectric materials, gas-sensing, solar cells and photocatalyst. In this study, we synthesized ZnO nanoparticles and defined their physical and chemical properties. Also we studied about the application of ZnO nanoparticles as a photocatalyst and try to find a enhancement photocatalytic activity of ZnO nanorticles.. We synthesized ZnO nanoparticles using spray-pyrolysis method and defined the physical and optical properties of ZnO nanoparticles in experiment I. When the ZnO are exposed to UV light, reduction and oxidation(REDOX) reaction will occur on the ZnO surface and generate ${O_2}^-$ and OH radicals. These powerful oxidizing agents are proven to be effective in decomposition of the harmful organic materials and convert them into $CO_2$ and $H_2O$. Therefore, we investigated that the photocatalytic activity was increased through the surface modification of synthesized ZnO nanoparticles. In experiment II, we studied on the stability of ZnO nanoparticles in water. It is well known that ZnO is unstable in water in comparison with $TiO_2$. $Zn(OH)_2$ was formed at the ZnO surface and ZnO become inactive as a photocatalyst when ZnO is present in the solution. Therefore, we prepared synthesized ZnO nanoparticles that were immersed in the water and dried in the oven. After that, we measured photocatalytic activities of prepared samples and find the cause of their photocatalytic activity changes.

• 한국약용작물학회지
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• 제25권2호
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• pp.89-94
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• 2017

Background: The purpose of improving the quality of oriental medicinal herbs is to contribute to the improvement of the income of farm. The present study investigated the effect of reasonable drying methods, different storage conditions and packageing materials on quality and stability of Scutellaria baicalensis Georgi and for developing GAP (good agricultural practice) guide book. Methods and Results: Three methods of drying Scutellaria baicalensis roots produced over two years were used to estimate loss rate owing to drying, storage, and packaging. The methods of drying were categorized into natural drying (36 - 60 h by sunshine), drying with heat dryer (2 - 10 h), or drying with gas bulk dryer (2 - 10 h). After cleaning, and initial drying for a few days under controlled temperature conditions, the second phase of drying was carried out at 35, 45 and $55^{\circ}C$. Changes in hunter color values and quality under the two studied storage treatments (at $20^{\circ}C$ indoors and at $4^{\circ}C$ in a refigerator) were evaluated. Storage period for 60, 120, and 180 days in three packaging materials, PE (polyethylene package), PP (polypropylene gunnysack), and WP (watertight packing paper) were studied. Conclusions: Initial cleaning, reasonable gas drying and hot air drying, and drying in an oven at 35 and $45^{\circ}C$ after cutting the roots resulted in the lowest loss rates in S. Baicalensis root. Hunter color valuse indicated that stroage of dry roots at room temperature was better than PP packaging, and that cold stroage was better than PE packaging for long-term stability.

• 분석과학
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• 제11권5호
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• pp.321-331
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• 1998

기체크로마토그래피/질량분석법(GC/MS)을 이용하여 물시료 중에 미량으로 함유된 19종의 여러고리방향족탄화수소류에 대한 액체-액체 추출법, disk추출법 및 고체상 추출법을 이용한 시료 매트릭스로부터 분리, 추출하는 방법을 조사하였다. GC/MS의 오븐온도프로그램을 $80{\sim}310^{\circ}C$까지 단계적으로 변화시킨 결과 19종의 PAH류를 분리할 수 있었다. 액체-액체 추출법에 의한 물시료 중 PAH류의 회수율은 71.3~109.5% 범위로 나타났고, filtration에 의한 $C_{18}$ disk추출법의 회수율은 80.7~94.9% 범위로 높게 나타났다. 그러나 $C_{18}$ Sep-Pak을 사용한 고체상 추출법의 회수율은 51.8~77.9%범위이었다. 이상의 추출법에 대한 추출 회수율, 재현성 및 실험의 편리성 등 장단점을 비교한 결과, $C_{18}$ disk를 사용한 거르기법이 PAH류의 추출에 가장 적합한 방법임을 확인하였다. 각 추출법의 검출한계(S/N=5)는 액체-액체 추출법 및 고체상 추출법의 경우 0.25~6.25 ppb, disk추출법은 0.05~1.25 ppb 범위이었다.