• Journal of the Korean Ceramic Society
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• v.54 no.5
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• pp.388-394
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• 2017

Here, utilizing rhodamine B (RhB) as standard color dye, we examined the photo degradation proficiency of $Ag_2Se-Graphene-TiO_2$ nanocomposites under visible light irradiation; samples were prepared by ultrasonication techniques and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopic investigation and UV-Vis absorbance spectra examination. Our outcomes demonstrate that the $Ag_2Se-G-TiO_2$ nanocomposite showed significant photodegradation efficiency as compared with those of $TiO_2-G$ and $Ag_2Se-G$, with around 85.2% of Rhodamine B (RhB) degraded after 180 min. It is concluded that the $Ag_2Se-G-TiO_2$ nanocomposite is a competent candidate for dye pollutants.

• Journal of the Korean Ceramic Society
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• v.54 no.3
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• pp.205-210
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• 2017

In this study, we examined the photo-degradation efficiency of $CoSe_2$-Graphene-$TiO_2$ ($CoSe_2-G-TiO_2$) nanocomposites under visible light irradiation using rhodamine B (RhB) as standard dye. $CoSe_2-G-TiO_2$ nanocomposites were synthesized by ultrasonication and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopic analysis and UV-Vis absorbance spectra analysis. Our results show that the $CoSe_2-G-TiO_2$ nanocomposite exhibited significant photo degradation efficiency compared to pure $TiO_2$ and $CoSe_2-G$, approximately 85.2% of the rhodamine (Rh B) degraded after 2.5 h. It is concluded that the $CoSe_2-G-TiO_2$ nanocomposite is a promising candidate for use in dye pollutants.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.308-313
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• 2017

In this study we examined the photo-degradation efficiency of $CoS_2-G-TiO_2$ nanocomposites under visible light irritation using Reactive Black B (RBB) as standard dye, $CoS_2-G-TiO_2$ nanocomposites synthesized by facial microwave assist technique, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopic analysis. Our results show the efficiency of the $CoS_2-G-TiO_2$ ternary nanocomposite is better than $CoS_2-G$ and $TiO_2-G$ nanocomposite. The degradation efficiency of $CoS_2-G-TiO_2$ nanocomposite was found approximately 89% of Reactive Black B (RBB) degraded after 180 min. Our results will open new way for the development of a new ternary nanocomposite photocatalytic application.

• Journal of the Korean Ceramic Society
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• v.29 no.12
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• pp.942-948
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• 1992

Ultrafine iron oxide powder, {{{{ gamma }}-Fe2O3 and $\alpha$-Fe2O3, were prepared by the thermal decomposition of organometallic compounds. The formation process of powder includes the thermal decomposition and oxidation of the organometallic precursors, Fe(N2H3COO)2(N2H4)2 (A) and N2H5Fe(N2H3COO)3.H2O (B). The organometallic precursors, A and B, were synthesized by the reaction of ferrous ion with hydrazinocarboxylic acid, and characterized by quantitative analysis and infrared spectroscopy. The mechanistic study for the thermal decomposition was performed by DAT-TG. The iron oxide powder was obtained by the heat treatment of the precursors at 20$0^{\circ}C$ and $600^{\circ}C$ for half an hour in air. The phases of the resulting product were proved {{{{ gamma }}-Fe2O3 and $\alpha$-Fe2O3 respectively. The particle shape was equiaxial and the particle size was less than 0.1 ${\mu}{\textrm}{m}$. Magnetic properties of the {{{{ gamma }}-Fe2O3 powder obtained from A and B was 234 Oe of coercivity, 64.26 emu/g of saturation magnetization, 23.59 emu/g of remanent magnetization and 24.1 Oe, 47.27 emu/g, 3.118 emu/g respectively. The value of $\alpha$-Fe2O3 powder was 1.494 Oe, 0.4862 emu/g, 0.1832 emu/g and 1,276 Oe, 0.4854 emu/g, 0.1856 emu/g respectively.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.264-265
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• 2014

This Paper reports the photocatalytic activity of $g-C_3N_4/NaTaO_3$ hybrid composite photocatalysts synthesized by ball-mill method. The $g-C_3N_4$ and $NaTaO_3$ were individually prepared by Solid state reaction and microwave hydrothermal process, respectively. The $g-C_3N_4/NaTaO_3$ composite showed the enhanced photocatalytic activity for degradation of rhodamine B dye (Rh. B) under simulated solar light irradiation. The results revealed that the band-gap energy absorption edge of hybrid composite samples was shifted to a longer wavelength as compared to $NaTaO_3$ and the 50 wt% $g-C_3N_4/NaTaO_3$ hybrid composite exhibited the highest percentage (99.6 %) of degradation of Rh. B and the highest reaction rate constant ($0.013min^{-1}$) in 4 h which could be attributed to the enhanced absorption of the hybrid composite photocatalyst in the UV-Vis region. Hence, these results suggest that the $g-C_3N_4/NaTaO_3$ hybrid composite exhibits enhanced photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation in comparison to the commercial $NaTaO_3$.

• ALGAE
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• v.28 no.4
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• pp.343-354
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• 2013

To explore the interactions between the mixotrophic dinoflagellate Biecheleria cincta (previously Woloszynskia cincta) and heterotrophic protists, we investigated whether the common heterotrophic dinoflagellates Gyrodinium dominans, Gyrodinium moestrupii, Gyrodinium spirale, Oxyrrhis marina, and Polykrikos kofoidii, and the ciliate Strobilidium sp. were able to feed on B. cincta. We also measured growth and ingestion rates of O. marina and Strobilidium sp. on B. cincta as a function of prey concentration. In addition, these rates were measured for other predators at single prey concentrations at which the growth and ingestion rates of O. marina and Strobilidium sp. were saturated. All grazers tested in the present study were able to feed on B. cincta. B. cincta clearly supported positive growth of O. marina, G. dominans, and Strobilidium sp., but it did not support that of G. moestrupii, G. spirale, and P. kofoidii. The maximum growth rates of Strobilidium sp. and O. marina on B. cincta (0.91 and 0.49 $d^{-1}$, respectively) were much higher than that of G. dominans (0.07 $d^{-1}$). With increasing the mean prey concentration, the specific growth rates of O. marina and Strobilidium sp. on B. cincta increased, but either became saturated or slowly increased. The maximum ingestion rate of Strobilidium sp. (1.60 ng C $predator^{-1}\;d^{-1}$) was much higher than that of P. kofoidii and O. marina (0.55 and 0.34 ng C $predator^{-1}\;d^{-1}$) on B. cincta. The results of the present study suggest that O. marina and Strobilidium sp. are effective protistan grazers of B. cincta.

• Analytical Science and Technology
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• v.17 no.3
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• pp.282-288
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• 2004

Inclusion selectivities of the cyanocadmate host complexes with ammonium oniums, $[Cd_x(CN)_{2x}][onium{\cdot}zG]$ (onium = $NMe_3Et^+$, $NMeEt{_3}^+$ and $NEt{_4}^+$, G = guest), have been investigated for $C_6H_6$ (B), PhMe (T), PhEt (E), ortho (O), meta (M), and para (P) isomers of $C_6H_4Me_2$ as the aromatic guest molecules. From the binary, ternary, quaternary and quinary mixed guests of B, T, E, O, M and P, the order of preference in the $NMe_3Et+$-host is $B{\gg}$T>P${\fallingdotseq}O{\fallingdotseq}M$ and E>O${\gg}P{\fallingdotseq}M$; in the $NMeEt{_3}^+$-host is T>B>P${\gg}O{\fallingdotseq}M$ and E>P${\gg}$M>O; in the $NEt{_4}^+$-host is $B{\gg}T{\fallingdotseq}O{\fallingdotseq}M{\fallingdotseq}P$. However, the $NEt{_4}^+$-host complexes of E, O, M and P mixed-guests were not obtained. These inclusion selectivities were compared to our previous results of the $NMe{_4}^+$-host; T>B>P${\gg}$M>O and E>P${\gg}$M>O.

• Journal of the Korean Magnetics Society
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• v.13 no.1
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• pp.36-40
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• 2003

We have grown D $y_{x}$B $i_{3-x}$F $e_{5}$ $O_{12}$ (x = 0.5,1.0, 1.5,2.0) magnetic garnet thin films upon $Al_2$O3i and GGG substrate using Pechini process. The annealing temperature to get single phase D $y_{x}$B $i_{3-x}$F $e_{5}$ $O_{12}$ garnet is dependent on substrate, i.e. the annealing temperature for GGG substrate il 5$0^{\circ}C$ lower than that for $Al_2$ $O_3$ substrate. The grains of garnet thin film grown on GGG (111) plane align along [111] direction, and in this case the hysteresis curve does not saturate up to H : 5000 Oe. We attribute this phenomenon to rotation magnetization process. The maximum amount of Bi substitution in polycrystalline D $y_{x}$B $i_{3-x}$F $e_{5}$ $O_{12}$ thin film prepared by Pechini process is restricted to 2.0 Bi atom/unit cell, and this value is less than that in single garnet crystall grown by LPE method.own by LPE method.ethod.

• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.594-605
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• 2022

CaO was prepared by calcining for oyster shells using a microwave kiln. It was analyzed to Ca(OH)₂ synthed on hydration reaction from prepared CaO. The synthesized Ca(OH)₂ was formulated as an external water paint. Oyster shells (325 mesh, 43 ㎛) were decarbonized for (a) 950 ℃/1 hr and (b) 1,150 ℃/1 hr to prepare CaO. In the calcination condition of (a), CaO was 56.7 wt%, and in the calcination condition of (b), CaO was 100 wt%. To compare CaO by calcination of oyster shells with that of limestone, limestone (25~30 mm) was decarbonized at 950 ℃/1 hr to prepare CaO, and as a result of the analysis(XRD), it was analyzed as CaO 100 wt%. CaO was prepared under the calcining conditions of oyster shells (b) 1,150 ℃/1 hr, and Ca(OH)₂ was synthesized through hydration. Hydration conditions of the prepared CaO were (a) CaO : H₂O(100 g : 200 g) and (b) CaO : H₂O(100 g : 400 g). As a result of the hydration reaction, it was confirmed as low reactivity. 100 wt% of Ca(OH)₂ was synthesized. In particular, Ca(OH)₂ synthesized under the hydration condition of (a) was analyzed in a plate shape. An external water paint was formulated with Ca(OH)₂ synthesized from oyster shells as the main component. When 15 items of the external water paint standard specification (KS M 6010) were analyzed, it was confirmed that all other criteria were satisfied except for freezing stability.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.384-389
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• 2014

The objective of the present study was to investigate the chemical composition of anthocyanin-enriched extract of radiation-induced blackberry (Rubus fruticosus L.) mutant (${\gamma}$-B201) as well as the protective effect of ${\gamma}$-B201 against oxidative stress in vitro. The cytotoxicity, reactive oxygen species (ROS) scavenging capacity, and DNA damage were assessed by WST-1 assay, flow cytometry, and comet assay, respectively. Lactate dehydrogenase, superoxide dismutase, and catalase activities were determined by using a commercial kit. The in vitro results showed that ${\gamma}$-B201 increased the cell viability, reduction of lactate dehydrogenase release, and intracellular ROS scavenging capacity in hydrogen peroxide ($H_2O_2$)-treated HepG2 cells. Furthermore, treatment with ${\gamma}$-B201 attenuated DNA damage in $H_2O_2$-treated HepG2 cells and treatment with ${\gamma}$-B201 restored the activity of superoxide dismutase and catalase in $H_2O_2$-treated HepG2 cells. In conclusion, the present study suggests that ${\gamma}$-B201 blackberry extract can exert a significant cytoprotective effect against $H_2O_2$-induced cell damage.