• Korean Journal of Materials Research
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• v.26 no.5
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• pp.258-265
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• 2016

Fluorine-doped tin oxide (FTO) nanoparticles have been successfully synthesized using ultrasonic spray pyrolysis. The morphologies, crystal structures, chemical bonding states, and electrochemical properties of the nanoparticles are investigated. The FTO nanoparticles show uniform morphology and size distribution in the range of 6-10 nm. The FTO nanoparticles exhibit excellent electrochemical performance with high discharge specific capacity and good cycling stability ($620mAhg^{-1}$ capacity retention up to 50 cycles), as well as excellent high-rate performance ($250mAhg^{-1}$ at $700mAg^{-1}$) compared to that of commercial $SnO_2$. The improved electrochemical performance can be explained by two main effects. First, the excellent cycling stability with high discharge capacity is attributed to the nano-sized FTO particles, which are related to the increased electrochemical active area between the electrode and electrolyte. Second, the superb high-rate performance and the excellent cycling stability are ascribed to the increased electrical conductivity, which results from the introduction of fluorine doping in $SnO_2$. This noble electrode structure can provide powerful potential anode materials for high-performance lithiumion batteries.

• Journal of the Korean Magnetic Resonance Society
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• v.3 no.1
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• pp.52-59
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• 1999

Authors synthesized common intermediates which are applicable for potential antibiotics. Their complete 13C and 1H NMR chemical shift data as well as carbon-and proton-fluorine coupling constants are reported. The knowledge of proton and carbon-fluorine coupling constants may help one assign the NMR data of the fluorinated quinolone derivatives. These results agree with the data published previously.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11b
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• pp.506-511
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• 1996

Research on the dry etching of UO$_2$ by using fluorine containing gas plasma is carried out for DUPIC (Direct Use of spent PWR fuel In CANDU) process which is taken into consideration for potential future fuel cycle in Korea. CF$_4$/O$_2$ gas mixture is chosen for the reactant gas and the etching rates of UO$_2$ by the gas plasma are investigated as functions of substrate temperature, plasma gas pressure, CF$_4$/O$_2$ ratio, and plasma power, It is tentatively found that the etching rate can reach 1000 monolayers/min. and the optimum CF$_4$/O$_2$ ratio is around 4:1.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.195-201
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• 2017

To study the effect of oxyfluorination on water dispersion of phthalocyanine blue(C.I. pigment blue 15:3), the pigment was oxyfluorinated using various oxygen to fluorine ratio of the reactant gas. After the oxyfluorination of the phthalocyanine blue pigment, no significant change in FT-IR spectra was observed, whereas XPS spectra showed the introduction of oxygen and fluorine containing functional groups. This suggests that the oxyfluorination of the pigment only occurred on the surface of the pigment particle and resulted in no significant change in UV-Vis spectra of the pigment. However, the oxyflurinated pigments showed improved water dispersion, compared to the non-treated pigment. Especially, when the oxygen to fluorine ratio was 47:3, the water dispersion of the oxyfluorinated pigments significantly increased, compared to the non-treated pigments. This suggests that the oxyfluorination of the phthalocyanine blue pigment has a potential to be used as a water dispersion improving method.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.617-621
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• 2009

Zinc oxide (ZnO) nanorods were grown on the pre-oxidized silicon substrate with the assistance of Au and the fluorine-doped tin oxide (FTO) based on the catalysts by vapor-liquid-solid (VLS) synthesis. Two types of ZnO powder particle size, 20nm, $20{\mu}m$, were used as a source material, respectively The properties of the nanorods such as morphological characteristics, chemical composition and crystalline properties were examined by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field-emission scanning electron microscope (FE-SEM). The particle size of ZnO source strongly affected the growth of ZnO nanostructures as well as the crystallographic structure. All the ZnO nanostructures are hexagonal and single crystal in nature. It is found that $1030^{\circ}C$ is a suitable optimum growth temperature and 20 nm is a optimum ZnO powder particle size. Nanorods were fabricated on the FTO deposition with large electronegativity and we found that the electric potential of nanorods rises as the ratio of current rises, there is direct relationship with the catalysts, Therefore, it was considered that Sn can be the alternative material of Au in the formation of ZnO nanostructures.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.234-239
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• 2015

Various leaching tests were applied to the soil affected by accidental leakage of HF in an industrial area in Korea. Three different leaching methods including pH-stat, continuous batch leaching, and column tests were adopted to assess leaching characteristics and mobility of fluorine(F) in soil and the potential risks to ecosystem. Both natural and spiked samples were used for the leaching tests. F concentrations in the batch tests increased by leaching rapidly in the early stage of leaching and then maintained rather constant levels. Column leaching test also show similar result to that of the batch test. pH also controlled the leaching behavior of the soil. With increasing pH, more F was released in the pH-stat test. This is mainly due to the competition and exchange with hydroxyl ions, as pH increase to the alkaline range. Most of the F released by the accident seem to have removed in the very early stage of leaching, whereas some natural proportion from soil minerals are thought to have been released very slowly. Therefore, little F released during the accident remained, based on the results of this study on the samples after two years of the accident. We could conclude that soil contaminated by external effects such as chemical accidents should be managed immediately, especially with F.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.3
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• pp.387-394
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• 2009

It has been observed that coated steel structures are rapidly deteriorated than designed lifetime due to acid rain caused by air pollution etc.. Therefore improvement of corrosion resistance of anti-corrosive paint is very important in terms of safety and economic point of view. In this study corrosion resistance for five kinds of anti-corrosive paints including acryl, fluorine and epoxy resin series were investigated with electrochemical methods such as corrosion potential, polarization curves, impedance and cyclic voltammogram measurements etc.. There were somewhat good relationships between values measured by electrochemical methods such as corrosion current density obtained by cathodic and anodic polarization curves, value of impedance estimated with AC impedance, and polarization resistance on the cyclic voltammogram, for example, corrosion current density was decreased with increasing of values of impedance and polarization resistance on the cyclic voltammogram. However their relationships between corrosion current density and corrosion potential were not well coincided each other. Consequently it is considered that although a corrosion potential of F101 of fuoric resin series shifted to negative direction than other anti-corrosive paints, its corrosion resistance, indicating on the cathodic and anodic polarization curves, AC impedance curves and cyclic voltammogram, was the most superior to other paints, whereas A100 containing arcylic resin showed a relatively poor corrosion resistance compared to other paints.

• Membrane Journal
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• v.23 no.3
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• pp.189-203
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• 2013

F-gases, gases containing fluorine such as perfluorocarbons (PFCs), sulfurhexafluoride ($SF_6$), nitrogen trifluoride ($NF_3$) are known to have green house effects. Although the net emission rates of gases containing fluorine are much lower than those of $CO_2$, their contribution to global warming cannot be ignored because of their extremely high global warming potential (GWP). F-gases mainly have been used for a variaty of applications in the semiconductor/LCD processes and in the electric power distribution industry of the national key industry. One of practical solutions of controlling the emission rates of F-gases is to reuse by separation and recovery of F-gases of low concentration from the gases mixtures with nitrogen or air. This work investigates some methods for F-gases recovery and separation around the membrane-based process.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.328-329
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• 2012

$SF_6$ gas는 반도체 및 디스플레이 제조공정 중 Dry etch과정에서 널리 사용되는 gas로 자연적으로 존재하는 것이 아닌 사용 목적에 맞춰 인위적으로 제조된 gas이다. 디스플레이 산업에서 $SF_6$ gas가 사용되는 Dry etch 공정은 주로 ${\alpha}$-Si, $Si_3N_4$ 등 Si계열의 박막을 etch하는데 사용된다. 이러한 Si 계열의 박막을 식각하기 위해서는 fluorine, Chlorine 등이 사용된다. fluorine계열의 gas로는 $SF_6$ gas가 대표적이다. 하지만 $SF_6$ gas는 대표적인 온실가스로 지구 온난화의 주범으로 주목받고 있다. 세계적으로 온실가스의 규제에 대한 움직임이 활발하고, 대한민국은 2020년까지 온실가스 감축목표를 '배출전망치(BAU)대비 30% 감축으로' 발표하였다. 따라서 디스플레이 및 반도체 공정에는 GWP (Global warming Potential)에 적용 가능한 대체 가스의 연구가 필요한 상황이다. 온실가스인 $SF_6$를 대체하기 위한 방법으로 GWP가 낮은 $C_3F_6$가스를 이용하여 $Si_3N_4$를 Dry etching 방법인 RIE (Reactive Ion Etching)공정을 한 후 배출되는 가스를 측정하였다. 4인치 P-type 웨이퍼 위에 PECVD (Plasma Enhanced Chemical Vapor Deposition)장비를 이용하여 $Si_3N_4$를 200 nm 증착하였고, Photolithography공정을 통해 Patterning을 한 후 RIE공정을 수행하였다. RIE는 Power : 300 W, Flow rate : 30 sccm, Time : 15 min, Temperature : $15^{\circ}C$, Pressure : Open과 같은 조건으로 공정을 수행하였다. 그리고 SEM (Scanning Electron Microscope)장비를 이용하여 Etching된 단면을 관찰하여 단차를 확인하였다. 또한 Etching 전후 배출가스를 포집하여 GC-MS (Gas Chromatograph-Mass Spectrophotometry)를 측정 및 비교하였다. Etching 전의 경우에는 $N_2$, $O_2$ 등의 가스가 검출되었고, $C_3F_6$ 가스를 이용해 etching 한 후의 경우에는 $C_3F_6$ 계열의 가스가 검출되었다.

• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1749-1754
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• 2009

Solubilities of carbon dioxide (C$O_2$) in a series of fluorine-free room temperature ionic liquids (RTILs), dialkylimidazolium dialkylphosphates and dialkylimidazolium alkylphosphites, were measured at 313∼333 K and pressures up to 5 MPa. Henry’s law coefficients as the solubility parameter of C$O_2$ in RTILs were derived from the isotherm of fugacity versus C$O_2$ mole fraction. The C$O_2$ solubility in a phosphorus-containing RTIL was found to increase with the increasing molar volume of the RTIL. In general, dialkylimidazolium dialkylphosphate exhibited higher absorption capacity than dialkylimidazolium alkylphosphite as long as the RTILs possess an identical cation. Among RTILs tested, 1-butyl-3-methylimidazolium dibutylphosphate [BMIM][B$u_2PO_4$] and 1-butyl-3-methylimidazolium butylphosphite [BMIM][BuHP$O_3$] exhibited similar Henry’s law coefficients to 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([BMIM][T$f_2$N]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][B$F_4$]), respectively. The Krichevsky-Kasarnovsky equation was employed to derive the C$O_2$ solubility parameter (Henry’s law coefficient) from the solubility data measured at elevated pressures.