• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.393-402
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• 1993

Redox flow secondary battery have been studied actively as one of the most promising electrochemical energy storage devices for a wide range of applications, such as electric vehicles, photovoltaic arrays, and excess power generated by electric power plants. In all-vanadium redox flow battery using solution of vanadium-sulfuric acid as a active material, the difficulty in developing an efficient ion selective membrane can still be identified. The asymmetric cation exchange membrane(M-30) as a separator of all-vanadium redox flow battery which were obtained by the reaction of chlorosulfonation for 30 minutes under the irradiation of UV, showed its superiority in the transport number of 0.94 and electrical resistivity of $0.5{\Omega}{\cdot}cm^2$. The base membrane were prepared by lamination a low density polyethlene film of $10{\mu}m$ thickness on polyolefin membrane(HIPORE 120). The electrical resistivity of M-30 membrane in real solution of vanadium-sulfuric acid was $3.79{\Omega}{\cdot}cm^2$ and it was similar to that of Nafion 117 membrane. Also the cell resistivity was $6.6{\Omega}{\cdot}cm^2$and lower than that of Nafion 117. In considertion of electrochemical properties and costs of membranes, M-30 membrane was better than that of Nafion 117 and CMV of Asahi glass Co. as a separator of all-vanadium redox flow battery.

• Clean Technology
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• v.23 no.2
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• pp.196-204
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• 2017

CdZnS/ZnO composite was prepared through low-temperature precipitation and drying method. The property of CdZnS/ZnO as a recyclable photocatalyst for the degradation of rhodamine B (RhB) under visible light irradiation was examined. The sample was characterized by XRD, FE-SEM, XPS, UV-vis DRS and photoluminescence techniques before and after repeated reaction to investigate the change of properties during the photocatalytic reaction. During repeated reaction, the CdZnS/ZnO showed an improved photocatalytic activity and recycle stability. Among two feasible reaction pathways for photocatalytic degradation of RhB, the cleavage of conjugated chromophore was found to predominate over N-dealkylation of chromophore skeleton in the present work. The results indicate that the CdZnS/ZnO, prepared by a simple precipitation method, can be used as a visible-light driven photocatalyst with enhanced cycle stability and activity.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.137-142
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• 2007

For the production of natural pigments with microbe, the strains which produced monascus pigment were isolated, and then culture condition and extraction condition were investigated. These results are summarized as follows; The strain which ran produce monascus natural pigment was isolated from natural microbial sources and we made mutant of this strain with UV($235_{nm}$, 30 second) irradiation. The mutant was identified as Monascus sp. MK2-2. The optimal culture conditions were investigated optimal medium containing 0.3% rice powder, 0.2% yeast extract, 0.3% $NH_4H_2PO_4$ and $30^{\circ}C$ in a rotary shaker (120 rpm) for 5 days (initial pH 5.0), while the pigment production was determined at 24 hr intervals. The effective carbon sources were wheat flour > rice powder > fructose, and effective nitrogen sources were sodium nitrate > $KNO_3$ for production of the monascus natural pigment. The pigment capacity is good from 17 to 22 in C/N ratio. The production amount of monascus natural pigment was 0.38 g per 1 kg of rice. Also, extract of red yeast rice had anti-thrombosis activity like a degree of aspirin.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3312-3318
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• 2014

For the sunscreen development from natural resources, a possible usage of microalgal extracts or mycosporine-like amino acids (MAAs) was investigated. Sunscreens containing 7% of microalgal extracts or MAAs derived from microalgae, Chlamydomonas hedleyi, were prepared and they were applied to human research. Through this clinical research, the values of Sun Protection Factors, Sun Protector Factor (SPF) and Protection Factor of UVA (PFA), of sunscreen containing microalgal extracts or MAAs were determined: SPF values of microalgal extracts and MAAs indicated 9.07 and 9.42, respectively, while PFA ones did 2.43 and 2.41. Due to more than 2 of PFA value in both sunscreens, they can be classified into [PA+]. Taken together, although sunscreen containing microalgae-derived extracts or MAAs does not effectively protect UV irradiation, its capacity can be satisfied if inorganic UV-protecting compounds are added.

• Polymer(Korea)
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• v.36 no.1
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• pp.71-75
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• 2012

In this study, silver nanoparticles (AgNPs) have been prepared by using aqueous $AgNO_3$ solution in the poly(vinyl alcohol) (PVA) hydrogels. PVA powders were dissolved in deionized water, and then irradiated by gamma-ray with a radiation dose of 50 kGy to make hydrogels. PVA hydrogels were dipped into 0.01 and 0.05 M $AgNO_3$ solution for 1 h respectively. After that, the swollen hydrogels were irradiated by gamma-ray at various doses to form AgNPs. UV-vis analysis indicated that the concentration of Ag NPs was enhanced by increasing absorbed dose and the concentration of $AgNO_3$. FE-SEM measurements provided further evidence for the successful formation of Ag NPs in PVA hydrogels. Also, the antibacterial effect of PVA hydrogels stabilized AgNPs against Gram-negative bacteria (S.aureus and E.coli) in liquid as well as on solid growth media has been investigated. The AgNPs consolidated in PVA hydrogel networks have an excellent antibacterial effect.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.351-359
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• 2015

Acute and chronic ultraviolet (UV) irradiation triggers severe skin photoaging processes, which directly disrupt the normal three-dimensional integrity of skin. UV light stimulates the expression of matrix metalloproteinases (MMPs) which degrade constituents of extracellular matrix (ECM) proteins. These MMPs reduce collagen synthesis and decrease skin elasticity and integrity, resulting in wrinkle formation. In this study, we identified Rosa multiflora hip extract (RME) as an effective anti-photoaging ingredient. First, cell proliferation activity of RME was verified using Hs68 human dermal fibroblast cell line. RME downregulated MMPs expression through the inhibition of activator protein (AP)-1. In addition, type I and IV collagen expressions were increased with RME treatment and UVB-induced inflammatory responses were also reduced after RME treatment. In conclusion, R. multiflora hip extract may effectively improve UVB-induced skin aging and wrinkle formation which may provide as an anti-aging, anti-wrinkle, and anti-inflammation ingredient in cosmetic industry.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.107-112
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• 2011

In this study, photocatalytic degradation and mineralization of bisphenol A (BPA), which has been listed as one of endocrine disruptors, were carried out in the CPC system using $Tio_2$ slurry and UVA irradiation. The degradation efficiency has been investigated under the controlled parameters including initial concentration (5, 10, 20 mg/L), dosage of $Tio_2$ (0.1, 0.5, 1.0 g/L), UVA power (0, 80, 120 W) and temperature (0, 20, 30). At 10mg/L of initial concentration, BPA was degraded above 80% after 10min, BPA were degraded 97% and 49% at 20 mg/L and 30 mg/L, respectively. At $Tio_2$ dosage was 0.1 and 0.5 g/L, the degradations of BPA showed similar trend and were about 70% after 1 hr, and the degradation of BPA was above 80% after 30 min at 1 g/L of $Tio_2$ dosage. The increase of degradation seem to be due to the increase in the total surface area, namely number of active sites, available for the photocatalytic reaction as the dosage of photocatalyst increased. When the UVA power was 120 W, BPA was degraded rapidly above 60% after 10min of reaction time. To investigate the effect of temperature, carried out experiment controlled temperature, there were no significant differences depending on the temperature. After 1hr, the degradation of BPA were 46%, 67%, and 69% at 10, 20 and $30^{\circ}C$.

• Membrane Journal
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• v.31 no.3
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• pp.219-227
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• 2021

Molecularly imprinted membrane (MIM) is a porous polymer membrane incorporating with the molecular recognizing sites. In this study, the supporting P(AN-co-MA) asymmetric membrane was prepared by nonsolvent induced phase separation (NIPS) method. And then, MIM with lysozyme template sites was prepared using the surface imprinting method on the P(AN-co-MA) asymmetric membrane introducing a photoactive iniferter and then photo-grafting. The P(AN-co-MA) asymmetric membrane was modified with 3-chloropropyltrimethoxysilane and dithiocarbamate as a photoactive iniferter. To prepare a lysozyme imprinted membrane, the modified P(AN-co-MA) membrane was copolymerized with acrylamide as a functional momomer, N,N'-methylene bisacrylamide as a crosslinker and lysozyme as a template in the UV irradiation environment. The lysozyme imprinted MIM was analyzed by using SEM, FT-IR and EDS measurements. Its results confirm that all the P(AN-co-MA) membranes have an asymmetric structure and the iniferter group is successfully introduced on the membrane surface. The process parameters were adjusted to obtain MIM having the excellent lysozyme adsorption. The maximum lysozyme adsorption capacity reaches at 2.7 mg/g, which is 13 times higher than that of the non imprinted membrane (NIM). The permselective membrane filtration experiments of ovalbumin to lysozyme show that the P(AN-co-MA) MIM preferentially bounds a greater amount of lysozyme.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.118-125
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• 2021

In this study Orostachys japonica A. Berger used is a medicinal herb that has long been used as a folk remedy for cancer treatment. In this study, the antioxidant efficacy of the ethyl acetate fraction of Orostachys japonica A. Berger was confirmed. The results of the Orostachys japonica A. Berge ethyl acetate fraction of antioxidant activity assays showed Antioxidant effect of Orostachys japonica A. Berger EtOAc fraction extract at 0.10 mg/mL was showed a DPPH radical scavenging rate of 78.54% and ABTS+ radical scavenging rate of 73.48%. Also, the toxicity result of Orostachys japonica A. Berger EtOAc fraction extracts using alternative experimental animal model zebrafish, confirmed a 100% the survival of the zebrafish embryo was shown that there was no coagulation and no hatching delay at all concentrations. also ROS generation induced by UV-B irradiation was confirmed that the fluorescence intensity decreased as a whole in all larvae treated with Orostachys japonica A. Berger EtOAc fraction extracts. In particular, it was confirmed that ROS generation was effectively suppressed by showing a 35.7% reduction rate compared to the positive control at a concentration of 3 ㎍/mL. These results were confirmed that Orostachys japonica A. Berger EtOAc fraction extracts has the possibility of application in the cosmetics field as a natural antioxidant.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.69-75
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• 2006

Improper disposal of petroleum and spills from underground storage tanks have created large areas with highly toxic contamination of the soil and groundwater. Methyl tert-butyl ether (MTBE) is widely used as a fuel additive because of its advantageous properties of increasing the octane value and reducing carbon monoxide and hydrocarbon exhausts. However, MTBE is categorized as a possible human carcinogen. This research investigated the Modified Photo-Fenton system which is based on the Modified Fenton reaction and UV light irradiation. The Modified Fenton reaction is effective for MTBE degradation near a neutral pH, using the ferric ion complex composed of a ferric ion and environmentally friendly organic chelating agents. This research was intended to treat high concentrations of MTBE; thus, 1,000 mg/L MTBE was chosen. The objectives of this research are to find the optimal reaction conditions and to elucidate the kinetic and mechanism of MTBE degradation by the Modified Photo-Fenton reaction. Based on the results of experiments, citrate was chosen among eight chelating agents as the candidate for the Modified Photo-Fenton reaction because it has a relatively higher final pH and MTBE removal efficiency than the others, and it has a relatively low toxicity and is rapidly biodegradable. MTBE degradation was found to follow pseudo-first-order kinetics. Under the optimum conditions, [$Fe^{3+}$] : [Citrate] = 1 mM: 4 mM, 3% $H_2O_2$, 17.4 kWh/L UV dose, and initial pH 6.0, the 1000 ppm MTBE was degraded by 86.75% within 6 hours and 99.99% within 16 hours. The final pH value was 6.02. The degradation mechanism of MTBE by the Modified Photo-Fenton Reaction included two diverse pathways and tert-butyl formate (TBF) was identified to be the major degradation intermediate. Attributed to the high solubility, stability, and reactivity of the ferric-citrate complexes in the near neutral condition, this Modified Photo-Fenton reaction is a promising treatment process for high concentrations of MTBE under or near a neutral pH.