• Korean Journal of Materials Research
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• v.20 no.3
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• pp.142-147
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• 2010

Nano-sized $BaNd_2Ti_5O_{14}$ powders were prepared by the spray pyrolysis process. Sucrose used as the organic additive enabled the formation of nano-sized $BaNd_2Ti_5O_{14}$ powders. The powders prepared from the spray solution without sucrose had a spherical shape, dense structure and micron size before and after calcination. However, the precursor powders prepared from the spray solution with sucrose had a large size, and hollow and porous morphology. The precursor powders had an amorphous crystal structure because of the short residence time of the powders inside the hot wall reactor. The complete decomposition of sucrose did not occur inside the hot wall reactor. Therefore, the precursor powders obtained from the spray solution with sucrose of 0.5M had a carbon content of 39.2wt.%. The powders obtained from the spray solution with sucrose of 0.5M had a slightly aggregated structure of nano-sized primary powders of $BaNd_2Ti_5O_{14}$ crystalline phase after calcination at $1000^{\circ}C$. The calcined powders turned into nano-sized $BaNd_2Ti_5O_{14}$ powders after milling. The mean size of the $BaNd_2Ti_5O_{14}$ powders was 125 nm.

• Fire Science and Engineering
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• v.26 no.4
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• pp.42-47
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• 2012

In the study, fire extinguishing concentration of $K_2CO_3$-Zeolite composite was measured. Zeolite composite is a porous adsorbent which has small particle size, low density and anti-catalytic effect. Scanning Electron Microscopy, X-Ray diffraction and thermal analysis were also conducted to investigate the structural properties of composite. The result showed that despite of weight ratio, the extinguishing concentration of the composite was lower than pure $K_2CO_3$. The extinguishing concentration of $K_2CO_3$-Zeolite composite which has weight ratio of 7 : 3 was 5.72 times lower than that of pure $K_2CO_3$ and 1.1 times lower than that of ABC powder. The SEM and XRD patterns showed that $K_2CO_3$ was adsorbed on the Zeolite properly, and through the thermal analysis, it was founded that the composite is more effective extinguishing agent than pure $K_2CO_3$.

• Korean Journal of Metals and Materials
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• v.50 no.3
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• pp.201-205
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• 2012

The effects of various manganese precursors for the low-temperature selective catalytic reduction (SCR) of $NO_x$ were investigated in terms of structural, morphological, and physico-chemical analyses. $MnO_x/TiO_2$ catalysts were prepared from three different precursors, manganese nitrate, manganese acetate(II), and manganese acetate(III), by the sol-gel method. The manganese acetate(III)-$MnO_x/TiO_2$ catalyst tended to suppress the phase transition from the anatase structure to the rutile or the brookite after calcination at $500^{\circ}C$ for 2 h. It also had a high specific surface area, which was caused by a smaller particle size and more uniform distribution than the others. The change of catalytic acid sites was confirmed by Raman and FT-IR spectroscopy and the manganese acetate(III)-$MnO_x/TiO_2$ had the strongest Lewis acid sites among them. The highest de-NOx efficiency and structural stability were achieved by using the manganese cetate(III) as a precursor, because of its high specific surface area, a large amount of anatase $TiO_2$, and the strong catalytic acidity.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.69-69
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• 2019

The distillation of liquid cathode is necessary to separate cadmium from the actinide elements in the pyroprocessing since the actinide deposits are dissolved or precipitated in a liquid cathode. It is very important to avoid a splattering of cadmium during evaporation due to the high vapor pressure. Several methods have been proposed to lower the splattering of cadmium during distillation. One of the important methods is an installation of crucible cover on the distillation crucible. A multi-layer porous round cover was proposed to avoid a cadmium splattering in our previous study. In this study, the effect of crucible cover on the cadmium distillation was examined to develop a splatter shield. Various surrogates were used for the actinides in the cadmium. The surrogates such as bismuth, zirconia, and tungsten don't evaporate at the operational temperature of the Cd distiller due to their low vapor pressures. The distillation experiments were carried out in a crucible equipped with cover and in a crucible without cover. About 40 grams of Cd was distilled at a reduced pressure for two hours at various temperatures. The mixture of the cadmium and the surrogate was heated at $470{\sim}620^{\circ}C$. Most of the bismuth remained in the crucible equipped with cover after distillation under $580^{\circ}C$ for two hours, whereas small amount of bismuth decreased in the crucible without cover above $580^{\circ}C$. The liquid bismuth escaped with liquid cadmium drop from the crucible without cover. It seems that the crucible cover played a role to prevent the splash of the liquid cadmium drop. The effect of the cover was not clear for the tungsten or zirconia surrogate since the surrogates remained as a solid powder at the experimental temperature. From the results of this work, it can be concluded that the crucible cover can be used to minimize the deposit loss by prevention of escape of liquid drop from the crucible during distillation of liquid cathode.

• Journal of Ginseng Research
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• v.45 no.5
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• pp.539-545
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• 2021

Background: Red ginseng polysaccharides (RGPs) have been acknowledged for their outstanding immunomodulation and anti-tumor activities. However, their studies are still limited by the complexity of their structural features, the absence of purification and enrichment methods, and the rarity of the analytical instruments that apply to the analysis of such macromolecules. Thus, this study is an attempt to establish a new mass spectrometry (MS)-based analysis procedure for RGPs. Methods: Saponin pre-excluded powder of RG (RG-SPEP, 10 mg) was treated with 200 µL of distilled water and centrifuged for 5 h at 1000 rpm and 85 ℃. Ethanol-based precipitation and centrifugation were applied to obtain RGPs from the heated extracts. Further, endo-carbohydrase treatments were performed to produce specific saccharide fragments. Solid-phase extraction (SPE) processes were implemented to purify and enrich the enzyme-treated RGPs, while matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) MS was employed for the partial structural analysis of the obtained RGPs. Results: Utilizing cellulase, porous graphitized carbon (PGC), hydrophilic interaction chromatography (HILIC), and MALDI-TOF/TOF MS, the neutral and acidic RGPs were qualitatively analyzed. Hex_n and Hex_n-18 (cellulose analogs) were determined to be novel neutral RGPs. Additionally, the [Unknown + Hex_n] species were also determined as new acidic RGPs. Furthermore, HexA_n (H) was determined as another form of the acidic RGPs. Conclusion: Compared to the previous methods of analysis, these unprecedented applications of HILIC-SPE and MALDI-TOF/TOF MS to analyze RGPs proved to be fairly effective for fractionating and detecting neutral and acidic components. This new procedure exhibits great potential as a specific tool for searching and determining various polysaccharides in many herbal medicines.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.463-471
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• 2019

Tapes are usually used in violent crimes and may contain important evidence. Separating adhesive side should be preceded to collect these evidence. In this study, we researched a novel dual-purpose reagent that can separate the tape without damaging and develop the fingerprints on porous surface when the tape is attached to A4 paper. As a result, the reagent of 1:2 ratio of 1,2-IND stock solution and HFE-7100 can separate without damaging the adhesive surface and develop fingerprints on separated A4 paper.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.2
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• pp.55-62
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• 2021

This study aims to reduce the rancid odor generated during the fermentation process of kimchi by inserting zinc oxide (ZnO) into an inorganic porous material with a high surface area to decompose or adsorb the fermentation odor. ZnO activated by the presence of moisture exhibits decomposition of rancid odors. Mixed with Titanium dioxide (TiO₂), a photocatalyst. To manufacture the packaging liner used in this study, NaOH, ZnCl₂, and TiO₂ powder were placed in a tank with diatomite and water. The sludge obtained via a hydrothermal ultrasonication synthesis was sintered in an oven. After being pin-milled and melt-blended, the powders were mixed with linear low-density polyethylene (L-LDPE) to make a masterbatch (M/B), which was further used to manufacture liners. A gas detector (GasTiger 2000) was used to investigate the total amount of sulfur compounds during fermentation and determine the reduction rate of the odor-causing compounds. The packaging liner cross-section and surface were investigated using a scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDS) to observe the adsorption of sulfur compounds. A variety of sulfur compounds associated with the perceived unpleasant odor of kimchi were analyzed using gas chromatography-mass spectrometry (GC-MS). For the analyses, kimchi was homogenized at room temperature and divided into several sample dishes. The performance of the liner was evaluated by comparing the total area of the GC-MS signals of major off-flavor sulfur compounds during the five days of fermentation at 20℃. As a result, Nano-grade inorganic compound liners reduced the sulfur content by 67 % on average, compared to ordinary polyethylene (PE) foam liners. Afterwards SEM-EDS was used to analyze the sulfur content adsorbed by the liners. The findings of this study strongly suggest that decomposition and adsorption of the odor-generating compounds occur more effectively in the newly-developed inorganic nanocomposite liners.

• Korean Journal of Metals and Materials
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• v.49 no.8
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• pp.596-600
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• 2011

Thermal degradation behavior of a $WO_3-TiO_2$ monolithic catalyst was investigated in terms of structural, morphological, and physico-chemical analyses. The catalyst with 4 wt.% $WO_3$ contents were prepared by a wet-impregnation method, and a durability test of the catalysts were performed in a temperature range between $400^{\circ}C$ and $800^{\circ}C$ for 3 h. An increase of thermal stress decreased the specific surface area, which was caused by grain growth and agglomeration of the catalyst particles. The phase transition from anatase to rutile occurred at around $800^{\circ}C$ and a decrease in the Brønsted acid sites was confirmed by structural analysis and physico-chemical analysis. A change in Brønsted acidity can affect to the catalytic efficiency; therefore, the thermal degradation behavior of the $WO_3-TiO_2$ catalyst could be explained by the transition to a stable rutile phase of $TiO_2$ and the decrease of specific surface area in the SCR catalyst.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.1
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• pp.5-9
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• 2008

Cordierite has a very low thermal expansion coefficient, but has problem that it has a weak mechanical strength and is apt to be attacked by acid such as sulfur for using as a diesel particulate filter support. The physical properties of $ZrTiO_4$ modified with $SiO_2,\;Al_2O_3$, MoOx, $Cr_2O_3\;and\;Nb_2O_5$ were investigated with XRD, SEM, UTM and thermal expansion, etc. in this paper. $ZrTiO_4$ powder was synthesized as a monoclinic structure with processes that starting materials of $TiO_2\;and\;ZrO_2$ were mixed with ball mill and calcined above $1240^{\circ}C$ for 3 hr. Additive modified $ZrTiO_4$ specimens for flexural strength and thermal expansion measurement were obtained by mixing $ZrTiO_4$ powder with additives, pressing and firing at $1300^{\circ}C$ for 3 hr. The porosity of additive modified $ZrTiO_4$ decreased monotonically with increasing additive content by 5 wt% regardless of additive types and saturated for further increase of additive by 10wt. The flexural strength of $Al_2O_3$ (5, 10 wt%) modified $ZrTiO_4$ shows a large increase, but that of other additives modified $ZrTiO_4$ decreased. The thermal expansion coefficient of additive modified $ZrTiO_4$ except $Nb_2O_5$ decreased continuously with the content of additive. In particular, the lowest thermal expansion coefficient of $ZrTiO_4$ was obtained for the additive of $SiO_2$.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.382-390
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• 2021

In this study, solubilized yuzu pulp powder (EYP) was produced using enzyme treated yuzu pulp powder (YP) and used to manufacture yuzu granules (0-20% EYP content). The physicochemical, product stability, and functional properties of Yuzu granules were compared among five enzyme treatments. Among the five treatments, CL had the highest YP solubilization yield (48.68%). Microstructural observation of EYP using FE-SEM revealed that its surface became irregular and porous after enzymatic treatment. Compared to YP, EYP had 2 times lower insoluble dietary fibers and 3 times lower hemicellulose and cellulose content. Among the yuzu granules, IV (yuzu granules with 15% EYP) had an excellent water and oil holding capacity and flowability. IV granule had the highest narirutin and hesperidin content of 3.4 mg and 2.2 mg/g DW, respectively and the highest antioxidant (68.4%) and tyrosinase inhibitory activities (82.5%). Therefore, EYP or granule with EYP can be used as a functional component in food industry or pharmaceutical field.