• Applied Chemistry for Engineering
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• 제9권5호
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• pp.619-623
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• 1998

The influences of reaction temperature, HF/DCM mole ratio, contact time and catalyst type on activity and selectivity of difluoromethane synthesis via hydrofluoriation of dichloromethane over fluorinated catalyst have been studied. It has been found that fluorinated $Cr/Al_2O_3$ catalysts, show better performance compared to pure fluorinated $Al_2O_3$ catalyst and then, non-treated catalysts demonstrate better than catalysts pretreated with hydrogen and air. The results show that the optimum reaction conditions are found as follows : reaction temperature at $340^{\circ}C$, mole ratio of HF/DCM 5 or above and contact time 20 sec. or above. With these conditions the maximum attainable yield of difluoromethane has been found to be greater than 80%. In particular, the activity and the selectivity of difluoromethane do not change with the reaction time on stream up to 8 hours.

• Journal of the Society of Cosmetic Scientists of Korea
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• 제23권3호
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• pp.75-81
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• 1997

It has been used that fluorinated compounds could be applied to cosmetic products. It is that fluorinated conpounds are hydrophobicity and lipophobicity. These fluorinated compounds are reported to form a highly protective and effective film against most aggressive chemical and physical agents. PerfluropolymethyoisopropylEther has homophobicity and are colorless, odorless, tasteless and non-greasy. In this we made a success to formulate the new type of hand care cream using PFPE. PFPE are suitable thickness and chemical inertness to skin. The reason that we select PFPE for this investigation. We developed the new type hand care cream by adsorption and dispersion of PFPE. There are very stable dispersion and highly moisture diffusion control. And these characteristics were verified by actual consumer test.

• Journal of the Society of Cosmetic Scientists of Korea
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• 제23권3호
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• pp.152-160
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• 1997

It has been used that fluorinated compounds could be applied to Make-up products. It is that fluorinated compounds are hydrophobicity, lipophobicity and homophobicity. These fluorinated compounds are reported to form a highly protective and effective film against most aggressive chemical and physical agents. In this study we maed a success to formulate the new type of lipstic using perfluoropolymethylisopropylether with low molecular weight which is long wearing and comfortable to use. This PPIE was adsorbed more than 90% in this experiment and formed the well-balanced gel networks even if the selected PPIE is 100% volatile at room temperature. On the basis of the adsorption of PPIE, we developed the new type lipstick, which was highly-lip feeling and had long wearing and non coloration. And these characteristics were verified by actual consumer test.

• Carbon letters
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• 제26권
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• pp.25-30
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• 2018

The dielectric medium used in electrophoretic displays (EPDs) is required to be an environmentally friendly solvent with high density, low viscosity, and a large electric constant. Hydrofluoroether, a highly fluorinated solvent with eco-friendly characteristics, is regarded as a viable alternative medium for EPDs, owing to the similarity of its physical properties to those of the conventional EPD medium. Surface modification of particles is required, however, in order for it to disperse in the charged solvent. Also, positive/negative charges should be present on the particle surface to enable electrophoretic behavior. In this study, carbon black particles wrapped with positively charged nitrogen (N-CBs) were fabricated by a simple hydrothermal process using a poly(diallyldimethylammonium chloride) solution as a black coloring agent for the EPD. The dispersion behavior of N-CBs was investigated in various solvents.

• Nuclear Engineering and Technology
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• 제44권1호
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• pp.21-32
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• 2012

Fluorinated compounds mainly used in the semiconductor industry are potent greenhouse gases. Recently, thermal plasma gas scrubbers have been gradually replacing conventional burn-wet type gas scrubbers which are based on the combustion of fossil fuels because high conversion efficiency and control of byproduct generation are achievable in chemically reactive high temperature thermal plasma. Chemical equilibrium composition at high temperature and numerical analysis on a complex thermal flow in the thermal plasma decomposition system are used to predict the process of thermal decomposition of fluorinated gas. In order to increase economic feasibility of the thermal plasma decomposition process, increase of thermal efficiency of the plasma torch and enhancement of gas mixing between the thermal plasma jet and waste gas are discussed. In addition, noble thermal plasma systems to be applied in the thermal plasma gas treatment are introduced in the present paper.

• Journal of Photoscience
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• 제9권1호
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• pp.23-28
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• 2002

In order to obtain thermal-stable, low birefringent, and low optical loss waveguiding materials, we synthesized several fluorinated poly (maleimide-co-glycidylmethacrylate)s using a pentafluorophenylmaleimide (PEM) and two kinds of methacrylate derivatives as comonomers and glycidylmethacrylate as a crosslinker. One comonomer is a linear fluorinated methacrylate (HFBM) and another is a bulky norbornane-derived methacrylate (NMMA). These copolymers could be self-crosslinked by heating due to epoxy groups of glycidylmethacrylates. As a maleimide contents increased to 50 mol%, these copolymers showed high decomposition temperatures of above 300$^{\circ}C$. The refractive index could be precisely controlled by the variation of PFM/HFBA or PFM/NMMA feed ratio in the range of 1.410∼1.508 at 643 nm. The copolymers had very low birefringence in the range of 1∼5${\times}$10$\^$-4/.

• Journal of Information Display
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• 제10권4호
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• pp.180-183
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• 2009

A stamping-assisted rubbing technique for generating bidirectional alignment in the fabrication of wide-viewing twistednematic (TN) liquid crystal displays (LCDs) was developed. A patterned layer of a fluorinated acrylate polymer was transferred onto the first rubbed alignment layer prepared on a substrate by stamping. The fluorinated acrylate polymer provides a protective layer that covers the first alignment layer during the second rubbing process to facilitate the bidirectional alignment of the LC molecules. The LC cell in the twisted geometry with two bidirectional-alignment layers showed stable electro-optic properties and wide-viewing characteristics. The stamping-assisted rubbing technique serves as a mask-free alignment method of producing multidomains for wide-viewing LCDs.

• Korean Journal of Clinical Laboratory Science
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• 제39권1호
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• pp.25-30
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• 2007

In this study, the two sampling methods for blood glucose measurement were evaluated in order to reduce pre-analytical error. For this purpose, glucose levels of Li-heparinized plasma (LHP) and Na-fluorinated plasma (NFP) in blood collected from healthy volunteers were determined by using routine hexokinase procedures. The percentage range of pre-analytical error was quantitated by comparing LHP glucose values with NFP glucose values according to delaying analytical time (0, 60, and 120 min). LHP glucose values were decreased by 6.6% in 60 min., 17.7% in 120 min, whereas NFP glucose values decreased by 1.1% in 60 min, 2.0% in 120 min. Therefore it may be recommended that the NFP sampling method should be used for routine blood glucose determination in diabetes mellitus diagnosis.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 한국반도체및디스플레이장비학회 2005년도 춘계 학술대회
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• pp.67-72
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• 2005

The bonding structure of organic materials such as fluorinated amorphous carbon films was classified into two types due to the chemical shifts. The electrical properties of fluorinated amorphous carbon films also showed very different effect of two types notwithstanding a very little difference. Fluorinated amorphous carbon films with the cross-link breakage structure existed large leakage current resulting from effect of the electron tunneling. Increasing the cation due to the electron-deficient group increased the barrier height of the films with the cross-link amorphous structure, therefore the electric characteristic of the final materials with low dielectric constant was also improved. The lowest dielectric constant is 2.3 at the sample with the cross-link amorphous structure.

• Elastomers and Composites
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• 제50권3호
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• pp.175-183
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• 2015

A series of fluorinated aromatic poly(hydroxyamide)s (PHAs) were synthesized by direct polycondensation of diacides containing 2,6-dimethylphenoxy group and quinoxaline ring in the main chain with 2,2-bis-(3-amino-4-hydroxyphenyl) hexafluoropropane. The PHAs had relatively low inherent viscosities in the range of 0.35~0.43 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs exhibited excellent solubility in aprotic solvents such as NMP, DMAc, DMF and DMSO as well as in common organic solvents such as pyridine, THF, and m-cresol at room temperature. However, the poly(benzoxazole)s (PBOs) were quite insoluble in all organic solvents except partially soluble in concentrated sulfuric acid. The PBOs showed glass transition temperatures between 233 and $284^{\circ}C$ by DSC and maximum weight loss temperatures in the range of $536-546^{\circ}C$ by TGA.