계면활성제가 함유된 O/W 에멀젼의 정밀여과막 흡착특성에 관한 연구

유종훈 수원대학교 산업기술연구소 2002 산업기술연구소논문집 Vol.17 No.-

In the present study the effect of the adsorption of an oil-in-water emulsion on the filtration performance of various microfiltration membranes with sponge-type pores was investigated. A commercially available cutting oil of emulsion type was employed as a test solution and four kinds of hydrophilic and hydrophobic membranes were used to study the variation in the permeate flux with their mean pore sizes and hydrophilicity. The experimental data obtained for all the membranes showed that the effect of the mean pore size on the emulsion adsorption is not very significant. For hydrophilic membranes, the effect of oil-in-water emulsion treatment on the permeate flux of pure water was found to be negligible. On the contrary, the effect of emulsion treatment on the permeate flux was observed to be significant for hydrophobic membranes: The adsorption of surfactant molecules in the oil-in-water emulsion on the pore walls resulted in a significant improvement in the permeate flux of pure water. However, higher transmembrane pressures were required for hydrophobic membranes compared those needed for hydrophilic membranes. Therefore, it is much more advantageous to employ hydrophilic membranes for the treatment of aqueous solutions oil-in-water emulsions.

다양한 유기용매를 이용한 보리순 내 천연 항산화제 및 색소 추출

유종훈 水原大學校 2015 論文集 Vol.29 No.-

Young green barley leaves are known to contain a significant amount of antioxidant flavonoids such as isovitexin and saponarin as well as natural pigments such as chlorophyll and beta-carotene. One of the most widely used methods to extract bioactive substances from plant materials is the organic solvent extraction. The main purpose of this study was to investigate the optimal conditions for maximizing the extraction efficiency of antioxidants and chlorophylls from young barley leaves. Using various organic solvents, soxhlet experiments were performed to select organic solvents suitable for the extraction of natural pigments and/or antioxidants. Ethanol was found to be very effective for pigment extraction, while methanol was most effective for antioxidant extraction.

평형 다분산계의 통계역학 이론

柳宗勳 수원대학교 산업기술연구소 1999 산업기술연구소논문집 Vol.14 No.-

A lattice model is employed to describe the thermodynamic properties of polydisperse systems in equilibrium such as solutions of polymer chains or flexible cylindrical micelles obtained from equilibrium processes. Two approaches are used to solve the lattice model. The mean-field solution of the n→0 vector spin model is compared to the results of a recursive lattice theory. The recursive lattice theory is obtained not by approximating the form of the energy and the entropy but by approximating the underlying lattice by the simplest recursive lattice known as a Bethe lattice. In the limit q→∞ the recursive lattice theory reduces to the mean-field solution of the n→0 vector spin model. The n→0 vector spin model cannot be applied to either monodisperse systems or polydisperse systems with intermolecular interactions. On the other hand, the recursive lattice approach does not have such limitations. Furthermore, systematic improvement of the theory can be made by using a more realistic recursive lattice than the Bethe lattice.

초임계 유체를 이용한 미세조류 바이오디젤의 직접 생산

유종훈,문성식 水原大學校 2014 論文集 Vol.28 No.-

In this study, we attempted to evaluate the feasibility of a supercritical methanol process for direct production of biodiesel from microalgae. The effects of various factors such as temperature, reaction time, water content and pretreatment on the efficiency of biodiesel conversion were investigated. The conversion efficiency increased with both temperature and extraction/conversion time. The supercritical methanol process produced a fatty acid methyl ester (FAME) yield of around 88% within 20 minutes. The optimal conditions for this process were found to be a microalgae/methanol ratio of around 1:9, a reaction temperature of about 270℃, and a reaction time of approximately 20 minutes. The effect of water content in microalgae samples on the FAME conversion was also evaluated. The supercritical methanol process was not affected by the water content up to 250 wt%. Our experiments demonstrated that the supercritical methanol process is more effective compared with conventional in situ transesterification processes.

초임계 유체를 이용한 두 종류의 항암제가 함유된 고분자 미립자 제조

유종훈 水原大學校 2012 論文集 Vol.26 No.-

Doxorubicin (DOX) is an anthracycline drug commonly used in the treatment of a large spectrum of tumors. It works by interfering with the growth of cancer cells. It binds and intercalates into the DNA strand, thus inhibiting further DNA and RNA biosynthesis, eventually causing cell death. Gemcitabine (GEM) is a synthetic pyrimidine nucleoside analogue with a high antitumor efficacy for ovarian, breast, bladder, and pancreatic cancer. It replaces one of the building blocks of nucleic acids, in this case cytidine, during DNA replication. The process arrests tumor growth, as new nucleosides cannot be attached to the faulty nucleoside, resulting in apoptosis. The purpose of this study is to prepare biodegradable poly(L-lactic acid) microparticles containing two different drugs by a supercritical aerosol solvent extraction system (ASES) process. The effects of operating parameters such as temperature, pressure, and drug composition on the morphology and characteristics of microparticles were studied in detail. The entrapment efficiency and in vitro release profiles of two anticancer drugs from the microparticles were also determined using HPLC. The entrapment efficiency increased with decreasing temperature. The entrapment efficiency of DOX was found to be higher than that of GEM, mainly due to larger molecular weight of DOX. On the other hand, GEM showed higher solubility in aqueous solution, thereby resulting in a faster release compared with DOX.

임계압력 근처에서 오일 에멀젼의 정밀여과 특성에 관한 실험 연구

유종훈,임교빈 수원대학교 산업기술연구소 2003 산업기술연구소논문집 Vol.18 No.-

In the present study the membrane filtration mechanism of an oil-in-water (O/W) emulsion through two kinds of straight-pore microfiltration membranes with average pore sizes of 0.2㎛ and 0.4 ㎛, respectively, has been investigated. An emulsion-type metalworking fluid has been permeated through these two membranes using a specially designed microfiltration apparatus. The theory on the critical pressure proposed by Nazzal and Wiesner railed to account for the experimental results obtained in this work. Our results revealed that O/W emulsions undergo a phase inversion to W/O emulsions above a certain concentration as the concentration of oil in the O/W emulsion increases near and on the membrane surface. A further increase in the transmembrane pressure resulted in the breakdown of the oil film formed on the membrane surface and, consequently, an abrupt increase in the permeate flux. Therefore, it has been suggested that the critical pressure should be redefined as the transmembrane pressure at which the oil film formed on the membrane surface starts to break down.

Self-Avoiding Random Walk의 연속체 및 격자 이론

柳宗勳 수원대학교 산업기술연구소 2000 산업기술연구소논문집 Vol.15 No.-

본 논문에서는 평형상태에서 중합된 고분자 용액의 배타부피 영향을 효과적으로 기술할 수 있는 self-avoiding random walk model의 grand canonical partition function과 강자성체의 거동을 기술하는 대표적인 모델 중의 하나인 vector spin model의 canonical partition function간의 상관관계를 필드이론과 격자이론의 관점에서 설명하였다. n → 0의 극한에서 고분자 또는 공중합 고분자와 강자성체간의 정확한 상관관계가 성립하며, 이 상관관계를 이용하면 강자성체계에 대해 이미 잘 정립된 다양한 이론을 사용해 다분간 고분자 용액의 거동을 해석할 수 있게 된다. 또한 n → 0 vector spin model의 고유한 성질인 평형 다분산성을 이용하면 평형 자기조합 과정을 매우 정확하게 기술할 수 있기 때문에 실린더형 미셀의 형성과 같은 여러 응용분야에 적용할 수 있을 것으로 기대된다.

미생물을 함유한 수용성 금속가공유의 여과 특성

柳宗勳 수원대학교 산업기술연구소 1998 산업기술연구소논문집 Vol.13 No.-

Separation characteristics of water-based semi-synthetic and synthetic cutting fluids containing microorganisms were studied by using various kinds of flat-type microfiltration and ultrafiltration membranes. It has been shown that microfiltration is not a sufficiently tight membrane to provide adequate separation of microorganisms, whereas very high rejection of microorganisms can be obtained when ultrafiltration membranes are used. Among those membranes used in this study YM100 seems to be best suited for the continuous reuse of water-based synthetic cutting fluids. It has also been shown that the application of membrane filtration technique for the regeneration of semi-synthetic cutting fluids is not very successful.

Gemcitabine-PLLA 컨쥬게이트의 합성과 초임계 유체를 이용한 Gem-PLLA 미립자 제조

유종훈 水原大學校 2013 論文集 Vol.27 No.-

Nano- and microparticulate drug delivery systems have widely been studied to achieve selective targeting of tumor cells through the enhanced permeability and retention effect. Conventional methods used to prepare drug-loaded polymeric nano- and microparticles include dialysis, emulsion/solvent evaporation and micelle technique. However, these methods generally have some limitations such as low drug loading efficiency, low drug distribution, and broad particle size distribution. In this study, to increase the loading efficiency of gemcitabine, an anti-tumor agent, gemcitabine-poly(L-lactic acid) (PLLA) conjugates were synthesized through an amide linkage reaction of N-hydroxysuccinimide with triethylamine. Then, gemcitabine-PLLA conjugate particles were prepared using a supercritical fluid process, called aerosol solvent extraction system (ASES) and their mean particle size and distribution as well as drug release profiles were investigated in detail. The FT-IR and 1H-NMR spectra confirmed that gemcitabine-PLLA conjugates were prepared successfully. The conjugation yield of Gem-PLLA varied significantly with the PLLA molecular weight. The Gem-PLLA particles obtained from ASES process showed a non-spherical shape and their mean size was varied from nano- to micro-scale depending on the PLLA molecular weight. No significant amount of gemcitabine was released in a phosphoric acid buffer solution of pH 7.4 up to 120 h at 37oC.

Itraconazole/HP-β-CD 포접복합체 제조를 위한 ASES 공정에 관한 연구

유종훈 수원대학교 산업기술연구소 2005 산업기술연구소논문집 Vol.20 No.-

In this work, solid-state inclusion complex powders of itraconazole and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) were produced by an aerosol solvent extraction system (ASES) process. In order to evaluate the properties of complexes, differential scanning calorimetry (DSC), x-ray diffraction (XRD) and solubility test in a buffer solution of pH 1.2 were carried out. The particle size of the ASES-processed inclusion complexes was dramatically reduced ( < 0.l~0.5㎛) compared with untreated itraconazole (30~50㎛) and HP-β-CD (50~100㎛). The aqueous solubility of the itraconazole complexed with HP-β-CD was significantly increased. At a constant temperature the aqueous solubility was increased with pressure and enhanced up to ca. 758.6 ㎍/mL in an aqueous medium of pH 1.2.