• Journal of the Microelectronics and Packaging Society
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• v.15 no.3
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• pp.41-46
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• 2008

Etching kinetics of $EAGLE^{2000TM}$ LCD glass was investigated using 2.5MHF-xMHCl$(x:0\sim8)$ acid mixtures. It was concluded that the reaction of HF-containing solutions with the glass was the rate-determining step for the dissolution process when considering following observations; the value of the activation energy $35\sim45$ kJ/mol and insensitivity of the dissolution rate to the etching time and the moving velocity of the glass into the solution. The etching rate linearly increased with increasing the HCl concentration in the etchant. It was also observed that the etched surface was as smooth as the original surface by addition of HCl and increase in etching temperature. This is due to the catalytic role of the $H_{3}O^{+]$ ions in the dissolution process.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.568-575
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• 1999

Two different digestion procedures for the simultaneous determination of major and platinum-group element(PGE) in spent automobile catalysts containing PGE and silicates by inductively coupled plasma atomic emission spectrometry(ICP-AES) are compared. Combinations of mixed aids using HF, $HNO_3$, HCl, $HClO_4$, $H_2O_2$, and $H_3BO_3$ are utilized for the hot plate dissolution method and the closed-vessel microwave digestion method, The latter method has been shown to be relatively superior in terms of recovery, analysis time, and amount of aqua regia (3 parts HCl + part $HNO_3$ required to dissolve PGE in comparison with conventional open vessel hot-plate dissolution. The best results were drawn from the following conditions: In closed Teflon PFA vessels under microwave heating with temperature/pressure regulation, a 0.25 g portion of sample was digested in 2 mL of HF, 2 mL of $HNO_3$ and 6mL of HCl under the pressure of 200 psi(13.79 bar) at $180^{\circ}C$ for 1hr, followed by a second digestion stage with 16 mL of 5%(w/v) boric acid under the pressure of 20 psi(1.38 bar) at $100^{\circ}C$ for 10 min. After the microwave heating, the sample was post-treated with 10 mL of aqua regia twice by hot-plate heating. This condition gives the PGE recovery within 85~110% and the relative standard deviations within 2%. The method developed can therefore be regarded as an alternative method for routine analysis of spent automobile catalysts.

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1067-1072
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• 2002

A new polystyrene-divinylbenzene resin containing 2-(2-thiazolylazo)-5-dimethylamino-phenol (TAM) functional groups has been synthesized and its sorption behavior for nineteen metal ions, including Zr(Ⅳ),Hf(Ⅳ) and U(Ⅵ) has been investigated by batch and column methods. The chelating resin showed high sorption affinity for Zr(Ⅳ) at pH 1-5 and U(Ⅵ) at pH 4. Some parameters affecting the sorption of the metal ions have been detailed. The breakthrough and overall capacities were measured under optimized conditions. The overall capacities of Zr(Ⅳ), Th(Ⅳ) and U(Ⅵ), which showed higher than the other metal ions, were 0.90,0.84 and 0.80 mmol/g, respectively. The elution order of metal ions at pH 4 was evaluated as Zr(Ⅳ) > Th(Ⅳ) > U(Ⅵ) > Cu(Ⅱ) > Hf(Ⅳ) > W(Ⅵ) > Mo(Ⅵ) > In(Ⅲ) > Sn(Ⅳ) > Cr(Ⅲ) > V(Ⅴ) > Fe(Ⅲ). Quantitative recovery of most metal ions except Zr(Ⅳ) was achieved using 2M HNO3. Desorption and recovery of Zr(Ⅳ) was successfully performed with 2 M HClO4 and 2 M HCl.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.319.1-319.1
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• 2016

Recently, the Al-doped ZnO (ZnO:Al) films are intensively used in thin film a-Si solar cell applications due to their high transmittance and good conductivity. The textured ZnO:Al films are used to enhance the light trapping in thin film solar cells. The wet etch process is used to texture ZnO:Al films by dipping in diluted acidic solutions like HCl or HF. During that process the glass substrate could be damaged by the acidic solution and it may be difficult to apply it for the inline mass production process since it has to be done outside the chamber. In this paper we report a new technique to control the surface morphology of RF-sputtered ZnO:Al films. The ZnO:Al films are textured with vaporized HF formed by the mixture of HF and H2SiO3 solution. Even though the surface of textured ZnO:Al films by vapor etching process showed smaller and sharper surface structures compared to that of the films textured by wet etching, the haze value was dramatically improved. We achieved the high haze value of 78% at the wavelength of 540 nm by increasing etching time and HF concentration. The haze value of about 58% was achieved at the wavelength of 800 nm when vapor texturing was used. The ZnO:Al film texture by HCl had haze ratio of about 9.5 % at 800 nm and less than 40 % at 540 nm. In addition to low haze ratio, the texturing by HCl was very difficult to control etching and to keep reproducibility due to its very fast etching speed.

• Analytical Science and Technology
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• v.17 no.6
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• pp.454-463
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• 2004

The sorption behavior of some metal ions on XAD-16-CTA chelating resin was investigated by batch method. The sorption of chelating resin was highly selective for Hf(IV), Zr(IV) and Th(IV) at pH 3.0 ~ 6.0 and the maximum sorption capacity of Zr(IV) ion was 0.81 mmol/g. It was successfully applied to the separation of several rare metal ions from mixed metal solutions by using CDTA, EDTA, NTA and $NH_4F$ as masking agent. The elution order of metal ions obtained from breakthrough capacity and the overall capacity at pH 4.0 was Zr(IV)>Th(IV)>Hf(IV)>U(VI)>Cu(II)>In(III)>Pb(II). Desorption characteristics for metal ions was investigated with desorption agents such as HCl, $HNO_3$, $HClO_4$. 2 M HCl showed high desorption efficiency. Th(IV) ion can be successfully separated from mixed metal ions by using XAD-16-CTA cheating resin.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.209-215
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• 2015

Following the semiconductor industry's growing, various types of toxic gases and caustic chemicals, HF(Hydrofluoric acid), HCI (Hydochloric acid), $H_2O_2$ (Hydrogen peroxide), $H_2SO_4$ (Sulfuric acid), and Piranha, were using on the semiconductor manufacturing process. Therefore many gas leakage accidents that produce huge losses of lives were caused by the processes. This research deeply considers two basic solutions that the necessity of MSDS education on university for reducing damage of lives and protecting life from chemical leak accidents such as a HF accident in Gumi, Korea and the use of GHS, REACH and the comprehension of propriety about using MSDS for keeping safety from conflagrations by released poison chemical materials.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1953-1961
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• 2005

We have performed high-level quantum mechanical calculation for multiple proton transfer in HOCl + HCl and $H_2O$ + $ClONO_2$ on water clusters, which can be used as a model of the reactions on ice surface in stratospheric clouds. Multiple proton transfer on ice surface plays crucial role in these reactions. The structures of the clusters with 0-3 water molecules and the transition state structures for the multiple proton transfer have been calculated. The energies and barrier heights of the proton transfer were calculated at various levels of theory including multi-coefficient correlated quantum mechanical methods (MCCM) that have recently been developed. The transition state structures and the predicted reaction mechanism depend very much on the level of theory. In particular, the HF level can not correctly predict the TS structure and barrier heights, so the electron correlation should be considered appropriately.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.681-692
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• 2013

We aimed to evaluate the effectiveness of the Giggenbach bottle method and develop the related pretreatment and analytical methods using artificial fumarolic gases. The artificial fumarolic gases were generated by mixing $CO_2$, CO, $H_2S$, $SO_2$, $H_2$, and $CH_4$ gas streams with a $N_2$ stream sparged through an acidic medium containing HCl and HF, with their compositions varied by adjusting the gas flow rates. The resultant fumarolic gases were collected into an evacuated bottle partially filled with a NaOH absorption solution. While non-condensible gases such as CO, $H_2S$, and $CH_4$ accumulated in the headspace of the bottle, acidic components including $CO_2$, $SO_2$, HCl, and HF that were dissolved into the alkaline solution. Like other acidic components, $H_2S$ also dissolved into the solution, but it reacted with dissolved $Cd^{2+}$ to precipitate as CdS when $Cd(CH_3COO)_2$ was added. The non-condensible gases were analyzed on a gas chromatography. Then, CdS precipitates were separated from the alkaline solution by filtration, and they were pretreated with $H_2O_2$ to oxidize CdS-bound sulfide into sulfate. In addition, a portion of the solution was also pretreated with $H_2O_2$ to oxidize sulfite to sulfate. Following the pretreatment, the resultant samples were analyzed for $SO_4^{2-}$, $Cl^-$ and $F^-$ on an ion chromatography. In the meanwhile, dissolved $CO_2$ was analyzed on a total organic carbon-inorganic carbon analyzer without such pretreatment. According to our experimental results, the measured concentrations of the fumarolic gases were shown to be proportional to the gas flow rates, indicating that the Giggenbach bottle method is adequate for monitoring volcanic gas. The pretreatment and analytical methods employed in this study may also enhance the accuracy and reproducibility of the Giggenbach bottle method.

• Analytical Science and Technology
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• v.12 no.6
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• pp.484-489
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• 1999

The extraction of trace amounts of Se in volcanic rock was investigated using the hydride generation method and atomic absorption spectrophotometry. The powdered rock, 1.0 g, was decomposed with the mixture of $HClO_4$, $HNO_3$ and HF in an acid digestion bomb at $140^{\circ}C$ for 2 hours. For the reduction of Se(VI) to Se(IV) in the solution, 10 mL of 6 M HCl and 0.2 mL of 1 M KBr were added to the solution and the mixture was heated for 30~45 minutes. $H_2Se$ was produced by adding 3% $NaBH_4$ as a strong reducing agent, extracted by nitrogen gas, and was absorbed twice into $KMnO_4$solution. The contents of Se in the solution were determined by generation/AAS. According to the proposed method, 1.0 ng or more of Se was quantitatively extracted and Se levels of 2.5 ng/g or more in rock samples could be determined. For example, Se in a rhyolite was determined with the precision of $19.5{\pm}1.3ng/g$(95% confidence, n=6).

• Analytical Science and Technology
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• v.14 no.4
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• pp.317-323
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• 2001

Dissolution procedures of Monsanto catalyst which has been used to produce acrylronitrile by ammoxidation of propylene have been studied. Optimum dissolution condition of the catalyst supported on silica was obtained by microwave digestion system with mixed of HCl, HF and $H_2O_2$. When a safety device was activated by increased pressure in microwave vessel, Bi, Fe, Mo, Sb and U were not volatilized even though silica was volatilized as $SiF_4$. Quantification results by this method were $SiO_2$ $50.5{\pm}0.4%$, $Sb_2O_3$ $29.6{\pm}0.6%$, $UO_2$ $10.2{\pm}0.1%$, $Fe_2O_3$ $6.1{\pm}0.1%$, $MoO_3$ $0.73{\pm}0.01%$ and $Bi_2O_3$ $0.49{\pm}0.01%$ by ICP-AES and the relative error was within ${\pm}10%$ except bismuth.