• Korean Journal of Materials Research
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• v.21 no.11
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• pp.596-603
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• 2011

The very high temperature gas reactor (VHTR) is one of the next generation nuclear reactors for its safety, long-term stability, and proliferation-resistance. The high operating temperature of over 800$^{\circ}C$ enables various applications with high energy efficiency. Heat is transferred from the primary helium loop to the secondary helium loop through the intermediate heat exchanger (IHX). The IHX material requires creep resistance, oxidation resistance, and corrosion resistance in a helium environment at high operating temperatures. A Ni-based superalloy such as Alloy 617 is considered as a primary candidate material for the intermediate heat exchanger. In this study, the microstructures of Alloy 617 crept in pure helium and air environments at 950$^{\circ}C$ were observed. The rupture time in helium was shorter than that in air under small applied stresses. As the exposure time increased, the thickness of outer oxide layer of the specimens clearly increased but delaminated after a long creep time. The depth of the carbide-depleted zone was rather high in the specimens under high applied stress. The reason was elucidated by the comparison between the ruptured region and grip region of the samples. It is considered that decarburization caused by minor gas impurities in a helium environment caused the reduction in creep rupture time.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.4
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• pp.223-229
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• 2004

The effects of the cooling and annealing conditions on the microstructures and corrosion properties were investigated for the Cu-contained Zr-Nb alloy (Zr-1.1Nb-0.07Cu). After annealing at $1050^{\circ}C$ for 15 min, the specimens were cooled by three methods of water quenching, air cooling, and furnace cooling. Widmanstatten structures were developed in both air- and furnace-cooled specimens, and the Widmanstatten plate width of the furnace-cooled specimens was wider than that of the air-cooled ones. The weight gain in the furnace-cooling case was higher than that in the air-cooling case. This could be the reason why the diffusion time was more enough during the furnace cooling than the air cooling. The oxide of the furnace-cooled specimen was nonunformly formed just beneath the Widmanstatten plate boundaries, where ${\beta}_{Zr}$ phases were exised concentrately. Compared with the $640^{\circ}C$ annealing after the water quenching, the $570^{\circ}C$ annealing could make the ${\beta}_{Nb}$ phases and a concomitant reduction of the Nb in the matrix, and then it could improve the corrosion resistance with the increase of the annealing time. It would be concluded that the corrosion resistance of the Zr-1.1Nb-0.07Cu was good when the Nb concentration in the matrix was reached at an equilibrium level and then the ${\beta}_{Nb}$ phase was formed.

• Bulletin of the Korean Chemical Society
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• v.8 no.2
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• pp.69-72
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• 1987

The structures of dehydrated $Ag_9Cs_3$-A treated with hydrogen gas at three different temperatures have been determined by single-crystal X-ray diffraction techniques. Their structures were solved and refined in the cubic space group Pm3m at 23(1) $^{\circ}C$. All crystals were ion exchanged in flowing streams of aqueous $AgNO_3$/$CsNO_3$ with a mole ratio 1:3.0 to achieve the desired crystal composition. The structures treated with hydrogen at $23^{\circ}C(a=12.288(1)\;{\AA})\;and\;310^{\circ}C(a=12.291(2)\;{\AA})$ refined to the final error indices R1 = 0.091 and R2 = 0.079, and 0.065 and 0.073, respectively, using the 216 and 227 reflections, respectively, for which I >3${\sigma}$(I). In both of these structures, eight $Ag^+$ ions are found nearly at 6-ring centers, and three $Cs^+$ ions lie at the centers of the 8-rings at sites of $D_{4h}$ symmetry. One $Ag^{\circ}atom$, presumably formed from the reduction of a $Ag^+$ ion by an oxide ion of a residual water molecule or of the zeolite framework during the dehydration process, is retained within the zeolite, perhaps in a cluster. In these two structures hydrogen gas could not enter the zeolite to reduce the $Ag^+$ ions because the large $Cs^+$ ions blocked all the 8-windows. However, hydrogen could slowly diffuse into the zeolite and was able to reach and to reduce about half of the $Ag^+$ ions in the structure only at high temperature ($470^{\circ}C$). The silver atoms produced migrated out of the zeolite framework, and the protons generated led to substantial crystal damage.

• The Korean Journal of Food And Nutrition
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• v.34 no.2
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• pp.196-206
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• 2021

The main purpose of this study was to examine the correlation between the consumption of red ginseng-based 'SSR' for 30 days and the reduction in human fatigue, blood component changes, and immune cell activity in 35 human subjects. 'SSR' is composed of zinc oxide, folic acid, and D-α-tocopherol with red ginseng as the main component. According to the protocol criteria of the study, 35 subjects who understood the purpose of the study and signed an informed consent form were selected. The fatigue survey was conducted through a questionnaire, and after taking 'SSR', a decreased tendency of physical, mental, and neurosensory fatigue was observed. In hematological analysis, no significant changes were observed in the levels of WBC, RBC, and hemoglobin; however, AST (SGOT) and ALT (SGPT) levels were statistically significantly decreased. In immunological analysis, it was observed that the proliferative effect of T cells (CD3+CD4+) was greater than that of NK cells (CD16+CD56+). The collected data were subjected to t-test analysis using the SPSS 25.0 statistical program. The result from this study proposes that 'SSR' can be used as a functional food material as it reduces human fatigue and enhances immune function.

• Journal of Physiology & Pathology in Korean Medicine
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• v.32 no.6
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• pp.396-402
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• 2018

Hataedock (HTD) treatment is a traditional preventive therapy for the fetal toxicosis- the acute allergic disease after childbirth, mainly manifested by a variety of skin allergies such as scab, phlegm. The aim of this study was to investigate the efficacy of HTD treatments for the alleviation of inflammation in Dermatophagoides farinae-induced obese NC/Nga mice. 20 mg/kg of Coptidis Rhizoma, Glycyrrhizae Radix (CRGR) extracts as a remedy of HTD treatments were orally administered to NC/Nga mice. We induced obesity in the mice by high-fat diet. To induce skin allergies, the extracts of Dermatophagoides farinae were topically applied on the NC/Nga mice at 4th-6th and 8th-10th weeks. Structural and molecular changes in the skin tissues were measured by immunohistochemical staining. HTD treatment decreased the atopic dermatitis (AD)-like symptoms including hemorrhage, erythema, erosion, edema, and dryness. HTD treatment suppressed the mast cell activation confirmed by reduction of $Fc{\varepsilon}RI$, substance P, and serotonin. The expression of several inflammatory mediators including nuclear factor-kappa B ($NF-{\kappa}B$) p65, inducible nitric oxide synthase (iNOS), vascular endothelial growth factors (VEGFs) was also decreased by HTD treatment. HTD treatment suppressed the allergic, inflammatory responses in the skin tissues of the NC/Nga mice by reducing mast cells and down-regulating several inflammatory mediators.

• Journal of the Korean Society of Food Culture
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• v.34 no.1
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• pp.84-92
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• 2019

Purpose: The objective of this study was conducted to investigate the effects of rutin, buckwheat components on cell growth and anti-inflammation in adipocyte 3T3-L1 and human colon cancer cell SW-480. Methods: We cultured 3T3-L1 adipocyte and SW-480 colon cancer cell to confluence, at which time starvation was induced with SFM for 1 day. Cells were then cultured in medium containing 0, 25, 50, or $100{\mu}mol/mL$ of rutin 3T3-L1 or 0, 10, 20, or $40{\mu}mol/mL$ SW-480. Cell viability was measured using a cell viability kit. In addition, we examined the expression of mRNA related to inflammation. RT-PCR was used to quantity tumor necrosis factor ($TNF-{\alpha}$), interleukin-$1{\beta}$ ($IL-1{\beta}$), IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) mRNA levels. Results: Rutin significantly inhibited 3T3-L1 and SW-480 cell proliferation in a dose and time dependent manner. Rutin also significantly reduced the mRNA expression of $IL-1{\beta}$, IL-6 and $TNF-{\alpha}$ at the highest dose. In addition, rutin treatment caused a significant reduction in COX-2 and iNOS mRNA levels compared to the control group. Conclusion: Overall, our results suggest that rutin has the potential to reduce inflammation, and that these effects are greater during tissue-damaging inflammatory conditions.

• Korean Journal of Materials Research
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• v.29 no.1
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• pp.1-6
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• 2019

Recent industrialization has led to a high demand for the use of fossil fuels. Therefore, the need for producing hydrogen and its utilization is essential for a sustainable society. For an eco-friendly future technology, photoelectrochemical water splitting using solar energy has proven promising amongst many other candidates. With this technique, semiconductors can be used as photocatalysts to generate electrons by light absorption, resulting in the reduction of hydrogen ions. The photocatalysts must be chemically stable, economically inexpensive and be able to utilize a wide range of light. From this perspective, cuprous oxide($Cu_2O$) is a promising p-type semiconductor because of its appropriate band gap. However, a major hindrance to the use of $Cu_2O$ is its instability at the potential in which hydrogen ion is reduced. In this study, gold is used as a bottom electrode during electrodeposition to obtain a preferential growth along the (111) plane of $Cu_2O$ while imperfections of the $Cu_2O$ thin films are removed. This study investigates the photoelectrochemical properties of $Cu_2O$. However, severe photo-induced corrosion impedes the use of $Cu_2O$ as a photoelectrode. Two candidates, $TiO_2$ and $SnO_2$, are selected for the passivation layer on $Cu_2O$ by by considering the Pourbaix-diagram. $TiO_2$ and $SnO_2$ passivation layers are deposited by atomic layer deposition(ALD) and a sputtering process, respectively. The investigation of the photoelectrochemical properties confirmed that $SnO_2$ is a good passivation layer for $Cu_2O$.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.136-146
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• 2019

A solid oxide fuel cell (SOFC) based hybrid desiccant cooling system model is developed to study the effect of fuel utilization rate of the SOFC on the reduction of energy consumption and $CO_2$ emission. The SOFC-based hybrid desiccant cooling system consists of an SOFC system and a Hybrid desiccant cooling system (HDCS). The SOFC system includes a stack and balance of plant (BOP), and HDCS. The HDCS consists of desiccant rotor, indirect evaporative cooler, electric heat pump (EHP), and heat exchangers. In this study, using energy load data of a commercial office building and SOFC-based HDCS model, the amount of ton of oil equivalent (TOE) and ton of $CO_2$ ($tCO_2$) are calculated and compared with the TOE and $tCO_2$ generation of the EHP using grid electricity.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.32 no.2
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• pp.1-10
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• 2019

Objectives : The objective of present study is to evaluate anti-inflammatory and anti-allergic effects of Perilla(Perilla frutescens; Labiatae, PF), the roots of Peucedanum praeruptorum(PP) and the root of Scutellaria baicalensis(SB) in vitro and anti-asthmatic effects of mixture of PF, PP and SB(PS) on ovalbumin (OVA)-induced asthma in BALB/c mice. Methods : Anti-inflammatory and anti-allergic effects were observed on the lipopolysaccharide(LPS) treated RAW 264.7 cells through Nitric Oxide(NO) production and RBL-2H3 cells through ${\beta}$-hexosaminidase. Anti-asthmatic effects were observed on the number of inflammatory cells in bronchoalveolar lavage fluid(BALF) and the level of IgE in serum on OVA-induced BALB/c mice. Results : The treatment of PF, PP and SB(12.5, 25, 50, $100{\mu}g/m{\ell}$) resulted in a significant inhibition of NO production in RAW 264.7 cells and mast cell degranulation in RBL-2H3 cells. Oral administration of PS(400mg/kg/day) resulted in a significant reduction in the numbers of eosinophils in BALF and level of IgE in serum. Conclusion : The oral administration of PS is effective in ameliorating the eosinophilic infiltration in vivo and thus can be a good therapeutic candidate for allergic asthma.

• Laboraroty Animal Research
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• v.33 no.1
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• pp.40-47
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• 2017

HemoHIM, herbal preparation has designed for immune system recovery. We investigated the anti-inflammatory effect of HemoHIM on cigarette smoke (CS) and lipopolysaccharide (LPS) induced chronic obstructive pulmonary disease (COPD) mouse model. To induce COPD, C57BL/6 mice were exposed to CS for 1 h per day (eight cigarettes per day) for 4 weeks and intranasally received LPS on day 26. HemoHIM was administrated to mice at a dose of 50 or 100 mg/kg 1h before CS exposure. HemoHIM reduced the inflammatory cell count and levels of tumor necrosis factor receptor (TNF)-${\alpha}$, interleukin (IL)-6 and IL-$1{\beta}$ in the broncho-alveolar lavage fluid (BALF) induced by CS+LPS exposure. HemoHIM decreased the inflammatory cell infiltration in the airway and inhibited the expression of iNOS and MMP-9 and phosphorylation of Erk in lung tissue exposed to CS+LPS. In summary, our results indicate that HemoHIM inhibited a reduction in the lung inflammatory response on CS and LPS induced lung inflammation via the Erk pathway. Therefore, we suggest that HemoHIM has the potential to treat pulmonary inflammatory disease such as COPD.