• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.92-98
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• 2015

In this study, phenol-based activated carbons (ACs) were fluorinated at various fluorine partial pressures (0.01~0.03 MPa) and the $Cr^{6+}$ ion adsorption of fluorinated ACs was investigated. According to BET and XPS results, the specific surface area and total pore volume of fluorinated ACs increased by 24.7 and 55.8%, respectively, and fluorine functional groups were introduced to AC surface. The most optimized condition of $Cr^{6+}$ ion adsorption was confirmed at the fluorine partial pressure of 0.02 MPa. And also the removal efficiency of $Cr^{6+}$ ion was up to 98% at 300 mg/L of the initial concentration, and these results showed an approximately three-fold increase compared to that of using untreated ACs. Furthermore, the $Cr^{6+}$ ion adsorption of fluorinated ACs was completed in less than 30 min in contrast with untreated ACs, which was expected to be an increase of the affinity between $Cr^{6+}$ ions and ACs surfaces by fluorination.

• The Korean Journal of Pharmacology
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• v.26 no.1
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• pp.91-100
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• 1990

The benzylacycoluridines (BAU and BBAU) are potent and specific inhibitors of uridine phosphorylase (UrdPase). In contrast to the report that benzylacyclouridines potentiated 5-fluoro-2'-deoxyuridine (FdUrd) cytotoxicity against human solid tumor cells (Cancer Res., 44:1852, 1984), continuous exposure of mouse lymphoma L5178Y cells, to FdURd, 5-fluorouridine (FUrd), 5'-deoxy-5-fluorouridine (5'-dFUrd), or 5-fluorouracil (FUra) showed no potentiation of cytotoxicity by benzylacyclouridines. In fact, under the conditions employed, benzylacycoluridines protected the cells from the cytotoxicity of FdUrd, FUrd, or 5'-dFUrd, but not FUra in a dose dependent manner. Intraperitoneal coadministration of BAU or BBAU and a 5-fluorinated pyrimidine (i.e., FdUrd, FUrd, or FUra), to mice bearing L5178Y cells also did not significantly increase the life span compared to those treated with the antimetabolites alone. Anabolism of these nucleosides through the sequential action of UrdPase and orotate phosphoribosyltransferase (OPRTase), inhibition of nucleoside transport by benzylacyclouridines, or both could be responsible for the ineffectiveness of UrdPase inhibitors to potentiate the antineoplastic activity of fluoropvrimidines in L5178Y cells.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.387-393
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• 2016

Fluorinated polyurethane coating solutions were synthesized from perfluoroalkyl alcohol, toluene diisocyanate, and polycarbonate diol as starting materials. Next, coating films were prepared by spin-coating the fluorinated polyurethane coating solutions on the PC substrates, followed by thermal curing at $120^{\circ}C$. The obtained fluorinated polyurethane coating films were characterized by FT-IR spectroscopy, UV-Vis spectrometer, contact angle tester and pencil hardness tester. Contact angle measurements of water on the coating films showed that the addition of perfluoroalkyl alcohol improved the water repellency and increased the contact angle from $81^{\circ}C$ to $111^{\circ}C$. However, the pencil hardness of coating films exhibited a constant grade of H, irrespective of the addition of perfluoroalkyl alcohol.

• BMB Reports
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• v.37 no.5
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• pp.586-596
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• 2004

The folding of ervatamin C was investigated in the presence of various fluorinated and non-fluorinated organic solvents. The differences in the unfolding of the protein in the presence of various organic solvents and the stabilities of O-states were interpreted. At pH 2.0, non-fluorinated alkyl alcohols induced a switch from the native $\alpha$-helix to a $\beta$-sheet, contrary to the $\beta$-sheet to $\alpha$-helix conversion observed for many proteins. The magnitude of ellipticity at 215 nm, used as a measure of $\beta$-content, was found to be dependent on the concentration of the alcohol. Under similar conditions of pH, fluorinated alcohol enhanced the intrinsic a-helicity of the protein molecule, whereas the addition of acetonitrile reduced the helical content. Ervatamin C exhibited high stability towards GuHCl induced unfolding in different O-states. Whereas the thermal unfolding of O-states was non-cooperative, contrary to the cooperativity seen in the absence of the organic solvents under similar conditions. Moreover, the differential scanning calorimetry endotherms of the protein acquired at pH 2.0 were deconvoluted into two distinct peaks, suggesting two cooperative transitions. With increase in pH, the shape of the thermogram changed markedly to exhibit a major and a minor transition. The appearance of two distinct peaks in the DSC together with the non-cooperative thermal transition of the protein in O-states indicates that the molecular structure of ervatamin C consists of two domains with different stabilities.

• Membrane Journal
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• v.30 no.5
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• pp.326-332
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• 2020

In this study, polymer-fluorinated silica composite hollow fiber membranes were fabricated and applied to a membrane contactor for the recovery of methane dissolved in the anaerobic effluent. To prepare the composite membranes, porous hollow fiber substrates were fabricated with Ultem^®, a commercial polyetherimide (PEI). Subsequently, fluorinated silica particles were synthesized and coated on the surface via strong covalent bonding. Due to the high porosity, our membrane showed a CH₄ flux of 8.25 × 10^-5 ㎤ (STP)/㎠·s at the liquid velocity of 0.03 m/s which is much higher that that of commercial polypropylene membrane designed for degassing processes. This is attributed to our membrane's high porosity as well as a superior surface hydrophobicity (120~122°) resulted from the coating with fluorinated silica nanoparticles.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.556-560
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• 2013

Recently, there are many efforts focused on development of more economical non-fluorinated membranes for use in PEMFCs (Proton Exchange Membrane Fuel Cells). In this study, characteristics of poly(arylene ether sulfone)(PAES) were compared with fluorinated membrane at PEMFC operation condition. I-V polarization curve, hydrogen crossover, electrochemical surface area, membrane resistance and charge transfer resistance were measured. PAES membrane showed similar performance compared with fluorinated membrane at 100% relative humidity, but the performance of PAES membrane decreased largely due to low ionic conductivity at low relative humidity.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.639-643
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• 2021

In this study, fluorinated ethylene propylene (FEP) nanoparticle as an adhesive for fabricating a three-dimensional multilayered microfluidic device was studied. The formation of evenly distributed FEP nanoparticles layer with 3 ㎛ in thickness on substrates was achieved by simple spin coating of FEP dispersion solution at 1500 rpm for 30 s. It is confirmed that FEP nanoparticles transformed into a hydrophobic thin film after thermal treatment at 300 ℃ for 1 hour, and fabricated polyimide film-based microfluidic device using FEP nanoparticle was endured pressure up to 2250 psi. Finally, a three-dimensional multilayered microfluidic device composed of 16 microreactors, which are difficult to fabricate with conventional photolithography, was successfully realized by simple one-step alignment of FEP coated nine polyimide films. The developed three-dimensional multilayered microfluidic device has the potential to be a powerful tool such as high-throughput screening, mass production, parallelization, and large-scale microfluidic integration for various applications in chemistry and biology.

• Korean Journal of Optics and Photonics
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• v.32 no.4
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• pp.180-186
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• 2021

Fluorinated polyimide has excellent light transmittance and a high optical refractive index, and is useful for producing optical-waveguide phase modulators with low optical loss and low electric power consumption. In this work, an optical-waveguide phase modulator is designed and fabricated based on a high-refractive-index fluorinated polyimide, and its characteristics are measured. An efficient protocol for characterizing the loss components of the optical waveguide is proposed, and the propagation loss of the fabricated polyimide optical waveguide is confirmed to be 0.9 dB/cm. The phase modulator requires 9.1 mW of power for phase change of π, and the response time is 290 μs, which is improved by tenfold compared to a previous demonstration of polymeric phase modulators.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.59-64
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• 2010

The synthesis of a series of fluorinated thiadiazoles 3, triazoles 4 and oxadiazoles 5 are synthesized from thiosemicarbazides 2 containing (2-(6-methyl-2-p-tolyl-lH-imidazo[1,2-a]pyridin-3-yl nucleus. These reactions were carried out by conventional method as well as ultra sound irradiation method. All products have been characterized by IR, 1H NMR, MS study and screened for their antimicrobial activity.

• Polymer(Korea)
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• v.39 no.3
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• pp.403-411
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• 2015

A series of hydrophobically associating fluorinated amphiphilic polyacrylamide copolymers with remarkably high heat resistance and salt tolerance were synthesized by free radical micellar copolymerization, using acrylamide (AM) and sodium 2-acrylamido-tetradecane sulfonate ($AMC_{14}S$) as amphiphilic monomers, and 2-(perfluorooctyl) ethyl acrylate (PFHEA) as hydrophobic monomer. The structure of the terpolymer was characterized by FTIR, $^1H$ NMR and $^{19}F$ NMR. The solution properties of the terpolymers were investigated in details, and the results showed that the terpolymer solution had strong intermolecular hydrophobic association as the concentration exceeded the critical association concentration 1.5 g/L. The terpolymer solution possessed high surface activity, viscoelasticity, excellent heat resistance, salt tolerance and shearing resistance. The viscosity retention rate of copolymer solution was as high as 59.9% under the condition of fresh wastewater, $85^{\circ}C$ and a 60-days aging test.