• Korean Membrane Journal
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• 제8권1호
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• pp.21-30
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• 2006

A faujasite NaY zeolite membrane was prepared on a tubular ${\alpha}-Al_2O_3$ support by the secondary growth process, and effects of permeation test conditions on the $CO_2/N_2$ separation were investigated. A NaY zeolite membrane with good $CO_2/N_2$ separation was successfully synthesized by using the hydrothermal solution ($Al_2O_3:SiO_2:Na_2O:H_2O$ = 1:6:14:840 in a molar base): at a permeation temperature of $30^{\circ}C$, its $CO_2$ permeance and $CO_2/N_2$ separation factor were $2.5{\times}10^{-7}mol/m^2secPa$ and 34, respectively. The $CO_2$ and $N_2$ permeations were highly dependent on permeation test conditions (feed composition, feeding rate, feed pressure, He sweeping rate and permeation temperature). The results indicated that (i) $CO_2$ and $N_2$ permeations through NaY zeolite membrane are governed by surface and micropore diffusions, respectively, (ii) the preparation of NaY zeolite membrane with a large permeating area is one of the most difficult hurdles for its real applications, and (iii) the retardation of $N_2$ permeation is an effective key to improve $CO_2/N_2$ separation factor in NaY zeolite membrane.

• 한국환경보건학회지
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• 제43권1호
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• pp.77-86
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• 2017

Objectives: The purpose of this study was to compare permeation characteristics in three skin types using oil-soluble benzoic acid and water-soluble caffeine after method condition optimization based on OECD guideline 428. Methods: A Franz diffusion cell, a reliable alternative method for skin permeation, was used. One-milliliter samples were taken and immediately replaced with fresh solution in the receptor chamber at regular time intervals (1, 2, 4, 7, 10 and 24 hr). The amount of test substances was measured by LC-MS/MS. Results: The permeation rate increased dose-dependently, and the permeation orders were $KeraSkin^{TM}$ > hairless mouse full skin > human cadaver epidermis for skin types, and benzoic acid solution > caffeine solution > benzoic acid cream > caffeine cream for type of test materials. Conclusion: According to the definitions of Marzulli, benzoic acid and caffeine would be classified as 'fast' and 'moderate' compared with the permeation of other chemical species. The setting conditions and permeation characteristics performed in this study are expected to contribute to future permeation studies.

• Journal of Pharmaceutical Investigation
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• 제30권1호
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• pp.27-32
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• 2000

Various release test methods have been applied for the evaluation of nicotine release in vitro from commercial patches. However, whether and how the release data reflect the permeation of nicotine across the skin, is not fully elucidated. To predict in vivo bioavailability from in vitro release tests, correlation between in vitro release and in vitro skin permeation was assessed in the present study. Release of nicotine from three commercial patches was measured for 24 hours under nine experimental conditions which were classified depending on the apparatus (i.e., paddle over disk, cylinder and reciprocating holder) and dissolution media (i.e., phosphate buffer pH 7.4, water and the 1 % phosphoric acid pH 1.5). In vitro permeation of nicotine from the patches across the human cadaver skin was also measured using a diffusion cell. The release of nicotine was better explained by the Higuchi's equation rather than by the first order rate equation. Correlation between the release rate and the in vitro skin permeation differed among the patches. However, in general, the cylinder method, in which water is used as a dissolution medium, showed the highest correlation among the nine release test conditions.

• 멤브레인
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• 제14권3호
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• pp.207-217
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• 2004

본 연구에서는 복합막의 제조공법으로 가장 광범위하게 쓰이는 계면중합법을 이용하여 나노복합막을 제조하였다. Monomer의 농도 및 조성, curing 조건, 후처리 조건과 같은 복합막 제조조건과, 운전압력, 공급액의 농도와 같은 운전인자에 의한 막성능 변화를 조사하였고, 계면중합 과정중에 첨가제를 사용하여 막의 유효면적을 확대하여 투과유속을 증가시키고자 하였다. Monomer의 농도가 증가함에 따라 배제능은 일정하였지만 투과유속이 감소하였고, curing 온도가 증가함에 따라서는 오히려 안정적인 박막층의 형성이 저해되어서 배제능과 투과유속이 모두 감소하였고, curing 시간에 따른 막성능의 변화는 나타나지 않았다. Test solution의 농도가 올라감에 따라서 투과유속과 배제능 모두 감소하였으며, 운전압력이 증가함에 따라서는 배제능과 투과유속 모두 향상하는 경향을 보였다. 계면중합과정중에 사용하는 아민단량체(amine monomer) 중 방향족 다이아민(aromatic amine)인 MPD의 함량을 높임에 따라서 배제능은 증가하였지만 투과유속은 현저하게 떨어졌다. 첨가제의 농도에 따른 표면 거칠기 증가 경향은 MPD가 포함된 amine 조성일 때가 더 높았지만 투과유속은 piperazine만 단독으로 사용하였을 때보다 떨어졌다.

• Bulletin of the Korean Chemical Society
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• 제28권1호
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• pp.99-102
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• 2007

To prepare freeze-dried ascorbyl palmitate (AsP)-containing liposome which can protect the drug from moisture attack and be used instantly by mixing with water for anti-aging and skin whitening therapy, AsP was encapsulated into liposomes and freeze-dried with trehalose. The freeze-dried liposome formulations were characterized by measuring water contents, particle size, time required for complete reconstitution. With the freeze-dried liposomes, we performed the stability test under accelerated conditions, skin permeation and localization test. The measurement of the time to perfect reconstitution showed that the freeze-dried liposomes can be changed to their initial state rapidly and short term stability test of AsP in reconstituted liposomes under accelerated conditions confirmed that the stability of AsP was considerably enhanced as compared to freshly prepared liposomes. The skin permeation and localization properties of AsP in reconstituted liposomes were not significantly different, indicating that the liposomal structures were maintained before and after freezedrying. In conclusion, the freeze-drying method provided a possible way to overcome the instability issue of AsP induced by the moisture and reproduced similar skin permeation and localization properties as shown by freshly prepared liposomes.

• 한국진공학회지
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• 제19권6호
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• pp.495-500
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• 2010

원자층 증착법(ALD: atomic layer deposition)을 이용하여 PES (poly (ether sulfon)) 기판위에 증착 온도, 플라즈마 파워에 따라 $Al_2O_3$와 $TiO_2$ 박막을 증착했다. 공정 조건에 따라 $Al_2O_3$와 $TiO_2$ 박막의 밀도, 탄소의 함유량이 달라지는 것을 알 수 있었으며, 공정 조건을 변화시켜 고밀도의 박막을 얻을 수 있었다. 플라즈마에 의한 PES 기판 손상을 막기 위해 buffer layer를 도입했으며, 또한 박막 내부 결함에 의한 수분 투과를 지연 또는 막기 위해 다층 구조를 증착했다. 이를 분석하기 위해 MOCON test를 이용해 투습률을 조사하였다. 플라스틱 기판에 다층 구조의 무기물 보호막을 적용했을 시 플라스틱 기판의 투습률 특성이 개선되었으며, 수분 투과에 대한 activation energy 또한 증가하는 것을 알 수 있었다.

• Corrosion Science and Technology
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• 제18권6호
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• pp.267-276
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• 2019

The purpose of this study was to examine the influence of conditions for quenching and/or tempering on the corrosion and hydrogen diffusion behavior of ultra-strong automotive steel in terms of the localized plastic strain related to the dislocation density, and the precipitation of iron carbide. In this study, a range of analytical and experimental methods were deployed, such as field emission-scanning electron microscopy, electron back scatter diffraction, electrochemical permeation technique, slow-strain rate test (SSRT), and electrochemical polarization test. The results showed that the hydrogen diffusion parameters involving the diffusion kinetics and hydrogen solubility, obtained from the permeation experiment, could not be directly indicative of the resistance to hydrogen embrittlement (HE) occurring under the condition with low hydrogen concentration. The SSRT results showed that the partitioning process, leading to decrease in localized plastic strain and dislocation density in the sample, results in a high resistance to HE-induced by aqueous corrosion. Conversely, coarse iron carbide, precipitated during heat treatment, weakened the long-term corrosion resistance. This can also be a controlling factor for the development of ultra-strong steel with superior corrosion and HE resistance.

• 한국안전학회지
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• 제21권3호
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• pp.53-58
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• 2006

Following a Mediterranean fruit fly outbreak in South Australia, a bait spray program involving the pesticides like malathion(MAL) was carried out. During the application, dermal exposure was considered for the pest controllers wearing PVC gloves. However there is a lack of information about PVC glove performance like break through times and permeation rates with MAL, therefore, a new analytical method for HPLC-UV was developed. A standard permeation test cell was used in this study. From the results of this study, more than 96% solubility of MAL was provided at 30% isopropyl alcohol in distilled water as a collecting media. However, there was significant decomposition of MAL when the solutions were kept at over $50^{\circ}C$ for 2-3 hours. As a mobile phase, 50% acetonitrile water solution (pH 6.0) gave the greater sensitivity compared with other compositions of acetonitrile solution. The arm section of the gloves had shorter breakthrough times and higher permeation rates compared with the palm. There was no malathion solution breakthrough up to 24 hours using the 1% MAL working strength solution. When the temperature was changed from $22{\pm}1^{\circ}C\;to\;37{\pm}1^{\circ}C$, the breakthrough times were decreased by 14.5% on palm and 37.5% on arm, and permeation rates were increased significantly. The findings of this study indicate that further investigations on used gloves, periods of use and varying working conditions like tasks and seasons should be carried out to assess potential worst case scenarios.

• Journal of Pharmaceutical Investigation
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• 제35권2호
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• pp.71-74
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• 2005

The aim of this study was to analyze characteristics of the barrier function of excised porcine buccal mucosa to the test compounds, estradiol, propranolol HCI, melatonin, and mannitol with a wide range of partition coefficient values. The permeability of melatonin was measured through frozen, stored, and fresh porcine buccal mucosa to examine the impact of storage conditions on the permeability of porcine buccal mucosa. The results demonstrated that the ex vivo permeability of the porcine buccal mucosa was greater for more lipophilic solutes, which was consistent with a series of molecules transported by passive transepithelial diffusion. The melatonin permeation profiles through frozen, stored, and fresh mucosa illustrated that damage was incurred by the freezing process of the mucosal tissue, leading to loss of the barrier function and thereby an increased permeation coefficient. It can be observed that the influence of compound lipophilicity on the association of the compounds with buccal mucosa was clear. The relationship between permeation coefficient and Log P values for the four compounds investigated demonstrated a proportional relationship, further confirming the importance of the lipophilicity of a compound to permeate the buccal mucosa. These results showed that the ex vivo porcine buccal mucosa model is a suitable tool to screen oral mucosal permeability.

• Korean Membrane Journal
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• 제8권1호
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• pp.36-42
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• 2006

We have prepared new water-swollen chitosan-$Ag^+$ complex membranes and studied their permeation and separation behavior for propylene and propane gases. The $Ag^+$ containing chitosan complex membranes were prepared from chitosan and $AgNO_3$ aqueous solution. The $AgNO_3$ and water content in the membrane were controlled by adjusting $AgNO_3$ concentration of casting solution. The permeation properties of propylene and propane were investigated as a function of $AgNO_3$ concentration, and various operation conditions. High permeability of above 17 barrer and high selectivity of above 170 could be obtained with the membranes prepared from 3 M $AgNO_3$ aqueous solution. Periodic regeneration test confirmed these membranes could be very useful for the separation of propylene/propane and other olefin/paraffin separation.