• 공업화학
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• 제9권4호
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• pp.475-480
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• 1998

본 연구에서는 고밀집 glassy carbon (GC) 섬유 다발체 전극 전해계를 사용하여 우라늄 (VI)를 함유한 유기상과 질산 수용상의 혼합상에서 전해 역추출시 우라늄 (VI) 환원 전해특성 연구가 수행되었고, 이에 관한 전해 역추출 모델을 제시하였다 우라늄 (VI) 전해환원 반응은 혼합상 내의 수용상에서 보다 혼합상 내의 유기상에서 빨리 일어났다. 유기상의 유속이 증가하는 경우 역추출 과정에서 유기상 내 우라늄 이온의 확산 저항 증가에 의해서 수용상으로의 역추출은 증가하다 일정하게 되었으며, 수용상 유속 변화는 총 우라늄 (VI) 환원전류에는 영향을 주지 않았다. 전해반응이 없는 경우보다 전해 반응이 동반되는 경우 우라늄 역추출이 보다 효과적으로 이루어 짐을 알 수 있었다.

• Journal of Pharmaceutical Investigation
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• 제34권6호
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• pp.471-475
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• 2004

Tamsulosin has been frequently used for the treatment of benign prostatic hyperplasia. To avoid dose-dependent side effects of tamsulosin upon oral administration, the development of sustained-release delivery system is required, that can maintain therapeutic drug levels for a longer period of time. The aim of this study was therefore to formulate sustained-release tamsulosin matrix tablets and assess their formulation variables. We designed enteric coated sustained-release tamsulosin matrices to fulfill above statement. Aqueous microchannels in the enteric film need to be formed in order to obtain tamsulosin release even in an acidic environment such as gastric region. In the sustained-release tamsulosin matrix, low viscosity hydroxypropylmethylcellulose was used as a rate controller. Povidone K30 was also added to the matrices to facilitate water uptake so that a decrease in the release rate of tamsulosin as time elapses was prevented, possibly leading to pseudo zero-order release of the drug. The matrices were enteric-coated with hydroxypropylmethylcellulose phthalate (HPMCP), along with povidone K30 as an aqueous microchannel former. With the aqueous microchannels formed within the enteric film, tamsulosin could be released in an acidic condition. The release of tamsulosin decreased with increasing thickness of HPMCP membrane while the release rates of tamsulosin from those having different HPMCP thickness in pH 7.2 aqueous media were not considerably different, indicating that the enteric film was promptly dissolved at pH 7.2. These results clearly suggest that the sustained-release oral delivery system for tamsulosin could be designed with satisfying drug release profile approved by the KFDA.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.875-883
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• 2015

The use of subcritical aqueous homogenous reactors driven by accelerators presents an attractive alternative for producing $^{99}Mo$. In this method, the medical isotope production system itself is used to extract $^{99}Mo$ or other radioisotopes so that there is no need to irradiate common targets. In addition, it can operate at much lower power compared to a traditional reactor to produce the same amount of $^{99}Mo$ by irradiating targets. In this study, the neutronic performance and $^{99}Mo$, $^{89}Sr$, and $^{131}I$ production capacity of a subcritical aqueous homogenous reactor fueled with low-enriched uranyl nitrate was evaluated using the MCNPX code. A proton accelerator with a maximum 30-MeV accelerating power was used to run the subcritical core. The computational results indicate a good potential for the modeled system to produce the radioisotopes under completely safe conditions because of the high negative reactivity coefficients of the modeled core. The results show that application of an optimized beam window material can increase the fission power of the aqueous nitrate fuel up to 80%. This accelerator-based procedure using low enriched uranium nitrate fuel to produce radioisotopes presents a potentially competitive alternative in comparison with the reactor-based or other accelerator-based methods. This system produces ~1,500 Ci/wk (~325 6-day Ci) of $^{99}Mo$ at the end of a cycle.

• 대한의용생체공학회:의공학회지
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• 제14권3호
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• pp.227-234
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• 1993

Hemofilter was optimally designed and manufactured using polysulfone hollow fiber mem- brane with surface area of 0.6mE Molecular weight cut-off of the hemofilter was measured with polyethylene glycol and dextran aqueous solutions of various molecular weights and it was ranged from 9,500 to 38,900. Ultrafiltration rates were measured with pure water in a static system and flowing system. The clearance of urea, creatinlne, and vitamine BIB were measured using aqueous solutions.

• 한국염색가공학회지
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• 제17권3호
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• pp.34-42
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• 2005

In this work, a practical separation performance was investigated on aqueous alcohol solutions, especially for iso-propyl alcohol (IPA), which is usually used during the semi- conductor rinsing process. The removal of various substances from waste aqueous IPA solutions was carried out by microfiltration with $0.1\~1{\mu}$m pore size of mean diameter as a pre-filter. Permeability and molecular weight cut-off of the functional polysulfone(PSf) ultrafiltration membrane to purify waste aqueous IPA solutions were measured through the ultrafiltration test. The solute rejection of PSf membrane had $92\%$ in 1,000ppm aqueous PEG solution with PEG molecular weight 10,000, the molecular weight cut-off had 10,000. The IPA concentration on the $CMPA-K^+$ membrane performance using pervaporation module system could be increased from $95.04 wt\%$ to more than $98.50wt\%$ in about 9hr at operation temperature of $70^{\circ}C$ using the pervaporation module system.

• 한국식품과학회지
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• 제28권1호
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• pp.197-202
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• 1996

콜레스테롤을 함유하는 수용성 모형계에서 erythrosine의 첨가농도, 광도, tocopherol과 ${\beta}-carotene$의 첨가에 따른 headspace내의 산소량의 변화와 콜레스테롤 산화물의 생성량의 변화를 연구하였다. Erythrosine의 첨가량이 증가할수록 headspace내 산소량의 감소가 컸고, 각종 COP 생성량은 증가하였다. 형광등의 조도가 증가할수록 headspace내 산소량의 감소가 컸고, 이에 비례하여 콜레스테롤은 감소하였고 총 COP의 생성량은 증가하였다. 일중항 산소 소거제로 tocopherol과 ${\beta}-carotene$을 첨가하였을 때 headspace내의 산소량은 완만하게 감소하였으며, 이에 비례하여 콜레스테롤의 감소가 완만하였고 총 COP의 생성량 또한 감소하였다.

• 전자통신동향분석
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• 제39권1호
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• pp.83-94
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• 2024

There have been continuous requirements for developing more reliable energy storage systems that could address unsolved problems in conventional lithium-ion batteries (LIBs) and thus be a proper option for large-scale applications like energy storage system (ESS). As a promising solution, aqueous metal-ion batteries (AMIBs) where water is used as a primary electrolyte solvent, have been emerging owing to excellent safety, cost-effectiveness, and eco-friendly feature. Particularly, AMIBs adopting mutivalence metal ions (Ca²⁺, Mg²⁺, Zn²⁺, and Al³⁺) as mobile charge carriers has been paid much attention because of their abundance on globe and high volumetric capacity. In this research trend review, one of the most popular AMIBs, zinc-ion batteries (ZIBs), will be discussed. Since it is well-known that ZIBs suffer from various (electro) chemical/physical side reactions, we introduce the challenges and recent advances in the study of ZIBs mainly focusing on widening the electrochemical window of aqueous electrolytes as well as improving electrochemical properties of cathode, and anode materials.

• 한국염색가공학회지
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• 제15권5호
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• pp.327-332
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• 2003

In this study, the polyurethane microcapsules for non-aqueous dyeing containing iron oxide and disperse dyes were prepared by in-situ polymerization method using hexamethylene diisocyanate(HDI) with ethylene glycol(EG). And the size, shape, and particle size distribution of microcapsules prepared were investigated. The size and shape of microcapsule were observed by optical microscope and scanning elecron microscope. The particle size distribution was analyzed by particle size analyzer. The microcapsule size and its distribution were largely effected by the existance of surface active agent in the system. When a surfactant did not exist in the system, the size distribution of microcapsules prepared was much uneven. By adding a surfactant, this phenomenon was disappeared. And the size of microcapsule was also effeced by the hydrophobicity of core material(disperse dye). It was considered due to the difference of dispersity of core materials. And the size of microcapsule prepared was inversely proportional to the stirring speed.

• 전기화학회지
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• 제5권4호
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• pp.216-220
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• 2002

The effects of electrolytes on electrochemical behavior from an oil thin layer interposed between a graphite electrode and an aqueous solution phase were examined. A hydrophobic electroactive species, tetrachloro-1,4-benzoquinone (TCQ), in a benzonitrile (EN) layer was employed to study ion transfer properties across the BN-water interface. Experimental results showed that hydrophobic cations as well as anions could be successfully used as ionic charge carriers. The addition of various salts into either the oil layers or the aqueous solutions offers deeper insight for the electrochemistry of the liquid thin layer system. When aqueous perchloric acid is interfaced with the BN films, the perchlorate ion of tetrahexylammonium perchlorate (THAP) substantially suppresses the dissociated proton concentration in the layer by the common ion effect while there is only a little change in the total acid concentration. Further approach by theoretical calculation makes it possible to quantitatively understand the effect of the electrolytes to the electrochemical responses of TCQ, which were previously reported (Anal. Chem. 73, 337 (2001)).

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.99-108
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• 2018

An oil-tolerant and salt-resistant aqueous foam system was screened out as a possible lubricant to enable cold heavy oil transportation. The microstructures and viscoelasticity and effects of heavy oil, salt and temperature on the foam stability were investigated and new rheological and drainage models were established. The results indicate the foam with multilayered shells belongs to a special microcellular foam. The viscoelasticity could be neglected due to its low relaxation time. The drainage process can be divided into three stages. The foam with quality of 67.9% maintains great stability at high oil and salt concentrations and appropriate elevated temperature.