• Korean Journal of Heritage: History & Science
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• v.47 no.1
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• pp.18-31
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• 2014

This study aims at identifying of characteristics and types of the pigments used for Dancheong(surface decorative and protective pigments) of Yaksajeon Hall in Gwallyoungsa Temple using a Micro-XRF, XRD, SEM-EDS and thereafter, comparing it with the pigments of the wall painting in the same building and with Dancheong pigments of Daeungjeon Hall. The results can be briefly summarized as two points. First, different types of pigments for red, green and white colours had been applied based on different parts of the building and more than two different pigments had been mixed to produce various colours in so me parts. Second, scientific analysis has confirmed that raw minerals for each colour groups are: Cinnabar, minium and Hematite for red; white clay and oyster shell white($Al_2O_3{\cdot}SiO_2{\cdot}4H_2O$) for white; Atacamite and Celadonite for green; carbon(C) for black; Yellow Ocher for yellow; and Lazulite for blue. Comparative analysis of such result with that of the wall paintings and of Dancheong of Daeungjeon Hall has revealed that similar minerals had been used in overall except that several different pigments had been added or removed for making green, white and yellow colour groups in some parts. In conclusion, the result has displayed that painters had used different ways of producing pigments by a type of painting or a building within the same period or for the buildings in the same buddhist temple compound.

• Journal of Life Science
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• v.31 no.2
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• pp.183-191
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• 2021

Euglena gracilis is a microalga of great biotechnological interest that can create high levels of bioactive compounds, such as tocopherol, paramylon, and folic acid. The objective of this study was to investigate the biological activities of extracts from E. gracilis, especially those focused on immunological activity. E. gracilis biomass was extracted with hot water (HWE) and the remaining pellet was continuously extracted with methanol (HWME). First, we examined the effect of two extracts from E. gracilis on the production of nitric oxide (NO) and the expression of pro-inflammation cytokines, including IL-1β, IL-6, and TNF-α in murine macrophage RAW 264.7 cells. HWE treatment dose-dependently increased the production of IL-1β and TNF-α. On the other hand, treatment with HWME significantly decreased the generation of NO and pro-inflammatory cytokines (IL-6 and TNF-α) in lipopolysaccharide (LPS)-stimulated macrophage cells. In addition, other biological activities of the extracts were further analyzed: α-glucosidase inhibition, protein tyrosine phosphatase (PTP1B) inhibition, tyrosinase inhibition, xanthine oxidase (XO) inhibition, and angiotensin-converting enzyme (ACE) inhibition. Analysis of these biological activities showed that HWE has more inhibitory effects than HWME against α-glucosidase, tyrosinase, and XO agents. However, the inhibition of PTP1B and ACE with HWME were higher than with HWE. Taken together, the results suggested that E. gracilis possesses various biological activities―especially immunological capabilities―through regulation of cytokine production. Therefore, E. gracilis extract may be potentially useful for food material with immune-regulating effects.

• Journal of Life Science
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• v.31 no.1
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• pp.1-9
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• 2021

Brown seaweeds have been shown to decrease blood glucose levels and improve insulin sensitivity previously. In this study, we investigated the effect of fucoidan, a complex polysaccharide derived from brown seaweeds, on glucose uptake to improve insulin resistance, and examined its mechanism of action in 3T3-L1 adipocytes. We observed that fucoidan significantly increased glucose uptake and it was related to an increased expression of plasma membrane-glucose transporter 4 (PM-GLUT4) in 3T3-L1 adipocytes. Fucoidan treatment increased the activation of phosphatidylinositol-3-kinase (PI3K) and the phosphorylation of insulin receptor substrate 1 (IRS1tyr) compared with that of the control cells. Fucoidan also promoted the phosphorylation of Akt and protein kinase C (PKC)-λ/ζ compared to that of the control cells. Moreover, fucoidan significantly upregulated acetyl-CoA-carboxylase (ACC) and adenosine monophosphate - activated protein kinase (AMPK) phosphorylation. As a result, translocation of GLUT4 was significantly enhanced in 3T3-L1 adipocytes, which significantly promoted glucose uptake via the PI3K/AMPK pathways. The elevation of glucose uptake by fucoidan was blocked by inhibitor of PI3K and inhibitor of AMPK in 3T3-L1 adipocytes. These findings indicate that fucoidan might ameliorate glucose uptake through GLUT4 translocation to the plasma membrane by activating the PI3K/Akt and AMPK pathways in 3T3-L1 adipocytes. Fucoidan is thought to be of high material value to diabetes treatments and functional foods.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.67-71
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• 2011

The cathodic active material of $Li/SO_2Cl_2$ battery is $SO_2Cl_2$, which is the solvent of an electrolyte. It is referred to as a catholyte, a compound word of cathode and electrolyte. As the battery discharges, the catholyte burns out. And thus, the characteristics of the $SO_2Cl_2$ in the battery determine the capacity. In addition, the transition minimum voltage (TMV) and the voltage delay deviation of $Li/SO_2Cl_2$ battery are due to the passivation film formed by the reaction between an electrolyte and Li. Impurities in the electrolyte, such as moisture or heavy metal ions, will accelerate the growth of the passivation film. Therefore, a technology must be established to purify an electrolyte and to ensure the effectiveness of the purification method. In this research, $LiAlCl_4/SO_2Cl_2$ was manufactured using $AlCl_3$ and LiCl. Its concentration, the amount of moisture, and the metal amount were evaluated using an ionic conductivity meter, a colorimeter, and FT-IR.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.119-125
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• 2020

Transition metal dichalcogenides (TMDCs), two-dimensional atomic layered materials with direct bandgap in the range of 1.1-2.1 eV, have attracted a lot of research interest due to their high response to light and capability to build new types of artificial heterostructures. However, the large-area synthesis of high-quality and uniform TMDC films with vertical-stacked heterostructure still remains challenge. In this study, we have developed a metal-organic chemical vapor deposition (MOCVD) system for TMDCs and conducted a systematic study on the growth of single-layer TMDCs and their heterostructures. In particular, using a bubbler-type organometallic compound sources, the concentration and flow rate of each source can be precisely controlled to obtain uniformly single-layered MoS2 and WS2 films over the centimeter scale. In addition, the MoS2/WS2 vertical heterostructure was achieved by growing WS2 film directly on the MoS2 film, as confirmed by electron microscopy, UV-visible spectrophotometer, Raman spectroscopy, and photoluminescence spectroscopy.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.393-400
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• 2022

Postharvest quality of sweet pepper fruits was mainly defined as external appearance, i.e., shape, fruit weight and surface color. These quality traits tend to involve esthetic appeal, it disregards gustatory properties and nutritional value. However, comparative studies according to the marketability of sweet pepper fruits are insufficient. This study was carried out to compare the physicochemical components, antioxidant activity and carotenoid contents of marketable and unmarketable sweet pepper fruits (Capsicum annuum L.). Physicochemical components (proximate composition, minerals and total phenolic contents) and antioxidant activities using various methods were investigated. The proximate composition values (%) of marketable and unmarketable fruits were: moisture (90.28 and 90.29), ash (0.74 and 0.26), crude protein (0.67 and 0.72), crude lipid (0.38 and 0.32). There were no significant differences in antioxidant activity, while total phenolic content was higher in marketable fruit. Carotenoids contents were 29.3 ± 2.6 and 31.9 ± 2.9 ㎍·g^-1 in marketable and unmarketable fruits respectively, and identified β-carotene, violaxanthin, neoxanthin, and zeaxanthin. Lutein and capsaicin were not detected. In this study, potential value of unmarketable sweet pepper fruit could be identified to be applied as a food ingredient and functional food material.

• Journal of Mushroom
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• v.20 no.4
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• pp.218-226
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• 2022

Flammulina velutipes, known as winter mushroom in the family of Physalacriaceae, is the main edible and export mushroom with the third highest production after oyster and king oyster mushroom in Korea. However, as normal consumers regard F. velutipes as a simple subsidiary material, there is a limitation to increasing mushroom demand. In order to overcome the consumption limit and increase the differentiation of new varieties, it is necessary to breed varieties with enhanced functionality in consideration of consumer preferences. Therefore, the study was performed to analyze nutrient components and several useful functional substances with 26 genetic resources of F. velutipes. Analyses of inorganic compound(Ca, K, Mg) and 15 amino acids revealed that Strain 4148 had the highest content among the 26 strains. Beta-glucan, which increases immune activity and polyphenol, which exert antioxidant effects were higher in non-white strains than in white strains with a small number of exceptions. Among the five fatty acids, linoleic acid(an omega-6 fatty acid) and α-linolenic acid(an omega-3 fatty acid), were detected in six mushroom strains. α-linolenic acid, which was not found in five major mushrooms including oyster mushrooms, was identified in F. velutipes. The results of HPLC analysis showed that 'Auram' (Strain 4232) and 'Baekseung'(Strain 4230) had the highest content of the stabilizing neurotransmitter GABA(15.38 ㎍/ml and 20.56 ㎍/ml, respectively) among non-white and white strains, respectively. Our findings provide useful information for breeding F. velutipes to obtain strains with enhanced functionality.

• The Korea Journal of Herbology
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• v.29 no.3
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• pp.35-42
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• 2014

Objectives : Since single extract powders was released at 1987, the insurance fee has not been changed, but the price of raw material has been increasing. According to this, Pharmaceutical company couldn't invest on quality of the product, so, the quality of single extracts went down and lost the consumer's trust. We checked the contents of marker ingredients in single extract thereby to recover the reliability of insurance-covered herbal preparations. Methods : we bought total twelve products of eight different single extracts of two main pharmaceutical companies among total 65 kinds of single extract powder stipulated in KHP (The Korean Herbal Pharmacopoeia) monograph III at Jan. 2013. Assays of selected single extract powders are performed by KHP regulation. And we surveyed price fluctuation of relevant herb raw materials from 2005 to 2012. Results : Among twelve products, eight single extract powders were suitable by the KHP regulation. But four products didn't reach the content amount of KHP. Marker contents in the single extracts product of Pueraria Root, Licorice, Peony root and Scutellaria Root of A company were 70%, 1%, 23.7% and 75.1%, respectively. Conclusions : We can acertain whether there's a quality problem in the insurance-covered single extract powders. But, A company is no longer producing these improper single extract powders. As a medicine, single extract powders needs to be strictly quality controlled by the company, and regularly monitored by the KFDA.

• Korean Journal of Materials Research
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• v.34 no.4
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• pp.208-214
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• 2024

To fabricate intermetallic nanoparticles with high oxygen reduction reaction activity, a high-temperature heat treatment of 700 to 1,000 ℃ is required. This heat treatment provides energy sufficient to induce an atomic rearrangement inside the alloy nanoparticles, increasing the mobility of particles, making them structurally unstable and causing a sintering phenomenon where they agglomerate together naturally. These problems cannot be avoided using a typical heat treatment process that only controls the gas atmosphere and temperature. In this study, as a strategy to overcome the limitations of the existing heat treatment process for the fabrication of intermetallic nanoparticles, we propose an interesting approach, to design a catalyst material structure for heat treatment rather than the process itself. In particular, we introduce a technology that first creates an intermetallic compound structure through a primary high-temperature heat treatment using random alloy particles coated with a carbon shell, and then establishes catalytic active sites by etching the carbon shell using a secondary heat treatment process. By using a carbon shell as a template, nanoparticles with an intermetallic structure can be kept very small while effectively controlling the catalytically active area, thereby creating an optimal alloy catalyst structure for fuel cells.

• Journal of the Korean Electrochemical Society
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• v.8 no.4
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• pp.172-176
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• 2005

Recently, many researches on the high-voltage 5 V class cathode material have focused on $LiNi_{0.5}Mn_{1.5}O_4$, where $Mn^{3+}$ in the existing $LiMn_2O_4 (Li[Mn^{3+}][Mn^{4+}]O_4)$ is replaced by $Ni^{2+}(Li[Ni^{2+}]_{0.5}[Mn^{4+}]_{1.5}O_4)$ in order to utilize $Ni^{2+}/Ni^{4+}$ redox reaction in the 5V region. The partial substitution of Mn in $LiMn_2O_4$ for other transition metal element, $LiM_yMn_{1-y}O_4$(M=Cr, Al, Ni, Fe, Co, Cu, Ga etc) is known as a good solution to overcome the problems associated with $LiMn_2O_4$ like the gradual capacity fading. In this study, we synthesized $LiNi_{0.5}Mn_{1.5}O_4$ through a mechanochemical process and investigated its morphological, crystallographic and electrochemical characteristics. The results showed that 4 V peaks had been found in the cyclic volammograms of the synthesized powders due to the existence of $Mn^{3+}$ from the incomplete substitution of $Ni^{2+}$ for $Mn^{3+}$ implying that the mechanochemical activation alone was not good enough to synthesize an exact stoichiometric compound of $LiNi_{0.5}Mn_{1.5}O_4$. The synthetic condition of mechanochemical process, such as type of starting materials, ball-mill and calcination condition was optimized for the best electrochemical performance.