• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2613-2616
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• 2009

FeOOH/$TiO_2$, a heterojunction structure between FeOOH and $TiO_2$, was prepared by covering the surface of the $\sim$100-nm-sized FeOOH particles with Degussa P25 by applying maleic acid as an organic linker. Under visible light irradiation (${\lambda}{\geq}$ 420 nm), FeOOH/$TiO_2$ showed a notable photocatalytic activity in removal of gaseous 2-propanol and evolution of $CO_2$. It was found that FeOOH reveals a profound absorption in the spectral range of 400 - 550 nm, and its valence band (VB) level is located relatively lower than that of $TiO_2$. The considerable photocatalytic efficiency of the FeOOH/$TiO_2$ under visible light irradiation was therefore deduced to be caused by the hole transfer between the VB of FeOOH and $TiO_2$.

• Journal of Powder Materials
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• v.20 no.3
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• pp.210-214
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• 2013

This manuscript reports on compared color evolution about phase transformation of ${\alpha}-FeOOH@SiO_2$ and ${\beta}-FeOOH@SiO_2$ pigments. Prepared ${\alpha}$-FeOOH and ${\beta}$-FeOOH were coated with silica for enhancing thermal properties and coloration of both samples. To study phase and color of ${\alpha}$-FeOOH and ${\beta}$-FeOOH, we prepared nano sized iron oxide hydroxide pigments which were coated with $SiO_2$ using tetraethylorthosilicate and cetyltrimethyl-ammonium bromide as a surface modifier. The silica-coated both samples were calcined at high temperatures (300, 700 and $1000^{\circ}C$) and characterized by scanning electron microscopy, CIE $L^*a^*b^*$ color parameter measurements, transmission electron microscopy and UV-vis spectroscopy. The yellow ${\alpha}$-FeOOH and ${\beta}$-FeOOH was transformed to ${\alpha}-Fe_2O_3$ with red, brown at 300, $700^{\circ}C$, respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.10-15
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• 2020

This study is about the changes in mechanical and combustion properties after the production of the combustion catalysts FeOOH and Fe₂O₃ having the same manufacturing method and application to the solid propellant. In order to make the FeOOH and Fe₂O₃ having the same manufacturing method, FeOOH was calcined at 200, 300, 400, 500℃ for 2 h, and the XRD results were confirmed. In addition, after applying the prepared catalyst to a solid propellant, it exhibited change in mechanical and combustion properties. As result of XRD, FeOOH was confirmed to change the crystal phase from Geothtie to Hematite between 200 and 300℃. The stress of the propellant hardly changed as the calcination temperature of the combustion catalyst incredsed, but the elongation increased when catalyst was calcined. the maximum value at 300℃. The burning rate confirmed that FeOOH without calcination was about 3~5% faster than other catalysts.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.3
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• pp.292-296
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• 2024

In this study, Iron (III) oxide-hydroxide (δ-FeOOH) was successfully synthesized using hydrogen peroxide (H₂O₂) as an oxidizing agent. The synthesis of δ-FeOOH was carried out by controlling the amount of H₂O₂, and pure δ-FeOOH was successfully synthesized in ranges from 0.2 mL to 0.6 mL of H₂O₂. The size of the synthesized δ-FeOOH particles was compared by controlling the amount of oxidant H₂O₂. The average particle size of the synthesized pure δ-FeOOH particles increased from 875.1 nm to 897.2 nm as the amount of H₂O₂ was increased. The optical properties of δ-FeOOH synthesized under these specific conditions were investigated. All δ-FeOOH showed a similar trend of increasing and decreasing light absorption from 800 nm to 400 nm, although there was a slight difference in the amount of light absorption, with the largest amount of light absorption at 410 nm. The band gap energy of δ-FeOOH through the Tauc plot method was about 2.1~2.2 eV when H₂O₂ was 0.2~1.4mL. With a sufficient small particle size, simple control of that particle size, and a small band gap energy enough to absorb light in the visible spectrum, δ-FeOOH could be useful in a variety of applications, including photoelectrochemistry and battery electrodes.

• Journal of the Korean Ceramic Society
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• v.31 no.12
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• pp.1501-1506
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• 1994

The precipitate of FeCl2.4H2O and NaOH, Fe(OH)2 was rapidly made to oxidize by H2O2 to prepare $\delta$-FeOOH. The particle size, surface and morphology of $\delta$-FeOOH, and the shape and structure of thermally decomposed $\delta$-FeOOH were investigated by the use of high resolution STEM. $\delta$-FeOOH prepared under the condition of reaction temperature of Fe(OH)2 at 4$0^{\circ}C$, [OH-][Fe2+]=5 and aging time of 2 hr Fe(OH)2, had 630$\AA$ mean particle size, 4~5 aspect ratio, 20.8 emu/g saturation magnetization and 210 Oe coercivity. The edges of $\delta$-FeOOH were inclined to (001) about 41$^{\circ}$, 60$^{\circ}$ and coincident with (102), (101) respectively. When $\delta$-FeOOH was thermally decomposed at 25$0^{\circ}C$ for 2 hr in vacuo, which had micropores of 0.9 nm thickness and crystallites of 2.4 nm thickness. (001)hex, [10]hex. of $\delta$-FeOOH parallel with (001)hex, [100]hex. of $\alpha$-Fe2O3 respectively. This showed three dimensional topotaxial structure transition, which was investigated by SADP (Selected Area Diffraction Pattern) of STEM.

• Korean Journal of Materials Research
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• v.10 no.1
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• pp.55-61
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• 2000

The sintering characteristics of PVA-Al(III) complex added $UO_2$ pellet and AlOOH added $UO_2$pellet were compared. The major phase of PVA-Al(III) complex and AlOOH decomposed at $1000^{\circ}C$ in $H_2$atmosphere was $\theta-Al_2O_3$. Compared with the apparent density of pure $UO_2$, that of AlOOH added $UO_2$ powder was higher but that of PVA-Al(III) complex was lower. the densification of AlOOH added $UO_2$ pellet was initiated at about $800^{\circ}C$, the densification of PVA-Al(III) complex added $UO_2$ pellet was initiated at about $900^{\circ}C$ respectively. In a view of pore size distribution, the PVA-Al(III) complex added $UO_2$ pellet appeared as monomodal type, whereas the AlOOH added $UO_2$ pellet appeared as bimodal type. The grain size of AlOOH added $UO_2$ pellet was about $13\mu\textrm{m}$ but the grain size of PVA-Al(III) complex added $UO_2$ pellet was increased up to about $36\mu\textrm{m}$.

• BMB Reports
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• v.32 no.3
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• pp.226-231
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• 1999

In vitro effects of acetone on cytochrome P450 (P450)-dependent benzo(a)pyrene (B(a)P) hydroxylation supported by cumene hydroperoxide (CuOOH) or NADPH/$O_2 $ systems were studied using 3-methylcholanthrene-pretreated rat liver microsomes. The maximal rate of B(a)P hydroxylation at constant concentration ($80\;{\mu}M)$ of the substrate was observed in the presence of $30\;{\mu}M$ CuOOH. However, at concentrations higher than $30\;{\mu}M$ CuOOH the hydroxylation rates were rapidly decreased. In contrast to CuOOH, at a concentration of $200\;{\mu}M$ NADPH, B(a)P hydroxylation rate reached a plateau. At concentrations higher than $200\;{\mu}M$ NADPH, the rates of substrate hydroxylation were maintained at the maximal rate with no inhibition. Acetone at 1% (v/v) enhanced both CuOOH- and NADPH/$O_2$-supported B(a)P hydroxylation at the optimal concentrations of the cofactors. At concentrations higher than 1% (v/v) acetone, substrate hydroxylation was sterero specific under the support of these two cofactors; it was strongly enhanced with $30\;{\mu}M$ CuOOH, but rather inhibited in the $200\;{\mu}M$> NADPH/$0_2 $ system. The lipid peroxidation rate induced during CuOOH-supported P450-dependent B(a)P hydroxylation was increased as CuOOH concentrations were increased. Acetone in the concentration range of 2.5~7.5%(v/v) inhibited lipid peroxidation during CuOOH supported B(a)P hydroxylation. The finding that CuOOH-supported B(a)P hydroxylation is greatly enhanced by acetone suggests that acetone may contribute more to the activation of oxygen (for the insertion of oxygen into the substrate) in the presence of CuOOH than with NADPH/$O_2$. Acetone may also contribute to the partial inhibition of destruction of microsomal membranes by lipid peroxidation.

• Journal of the Korean Ceramic Society
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• v.33 no.3
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• pp.327-331
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• 1996

$\delta$-FeOOH was prepared by rapid oxidation method of Fe(OH)2 using H2O2. The effects of reaction temperature and mole ratio ([OH-]/[Fe2+])의 몰비를 제조 변수로 하여 최종 생성된 $\delta$-FeOOH의 입자크기 입자형태, 자기특성을 조사하였다. Fe(OH)2 의 반응온도 및 [OH-]/[Fe2+] 비가 $\delta$-FeOOH의 입자크기 및 형상에 많은 영향을 미침을 알수 있었으며 입자 크기는 이 두인자에 비례하여 증가하였다 Fe(OH)2 의 반응온도가 4$0^{\circ}C$ [OH-]/[Fe2+]=5 Fe(OH)2 숙성 시간 2시간에서 제조된 $\delta$-FeOOH를 TEM, VSM으로 입자의 크기 및 자기특성을 조사한결과 평균 입경이 630$\AA$ 정도이고 입도 분포가 양호하였으며 포화자화 및 보자력은 각각 20.8emu/g 210 Oe였다.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.440-445
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• 1996

An attempt was made to study the relative composition of Monohydroperoxide isomers of methyl linoleate oxidized to different peroxide values at 60, 90, 120 and $150^{\circ}C$, respectively. HPLC was used to analyze and isolate the monohydroperoxide isomers fractionated by silica gel column after reduction with NaBH.. GC-MS was used to identify four monnhydroperoxide isomers as trimethylsilyl (TMS) in mixtures of oxidized methyl linoleate In the geometrical isomers, the proportions of 9/13-OOH-trans, trant-diene were higher than those of 9/13-OOH-cis, trans-diene at $60^{\circ}C$ and $90^{\circ}C$. However in the initial stage at $150^{\circ}C$, the proportions of 9/13-OOH-cis, trans-diene were slightly higher than those of 9/13-OOH-trans, trans-diene. In case of positional isomers, equal proportions of 9-OOH-10, 12-diene and 13-OOH-9, 11-diene were found in all samples of methyl linoleate oxidized at different temperatures and peroxide levels.

• Korean Journal of Clinical Pharmacy
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• v.32 no.2
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• pp.93-105
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• 2022

Objectives: This study aimed to identify the opinions of Gyeongsangbuk-do residents on out-of-hours (OOH) pharmacies and to examine the operating experiences of pharmacists who are operating OOH pharmacies in other areas. Methods: Cross-sectional survey was carried out for 1,000 Gyeongbuk residents employing a questionnaire via online or face-to-face, and 82 pharmacists who currently operate OOH pharmacies employing a postal questionnaire. Out of eighty-two, 46 pharmacists replied (response rate 56.1%). Results: As for the necessity of introducing OOH pharmacies in Gyeongsangbuk-do, 84.9% answered more than necessary. 86.1% favored the local government support for OOH pharmacies. The necessity of OOH pharmacies was highly evaluated among participants who experienced to be unable to use medicines or services in out of service hours, regardless of their characteristics or health condition. County residents consistently put a positive opinion for the necessity of OOH pharmacies if they have elderly family member(s), while city residents had significant differences across subgroups depending on their conditions (family members, household economics, health status, etc.). Almost all (95.7%) pharmacist participants highly evaluated the necessity of OOH pharmacies and the majority of them (63.0%) felt satisfied. However, 60.9% of participants have ever considered closing their OOH pharmacy business due to private, business management and professional reasons. Conclusion: This study made suggestions to address anticipated issues for the Gyeongbuk-style OOH pharmacy model.