• Journal of the Korean GEO-environmental Society
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• v.14 no.8
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• pp.23-27
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• 2013

In this study, efficiency of pre-treatment of turbid seawater was measured where micro-air bubbles were used to remove particles in seawater after input of natural coagulant PGA. Artificial seawater was prepared having the intended trubidity using marine sediments and microalgae. 73.7% of turbidity removal was achieved when 0.5g/L of $AlCl_3{\cdot}6H_2O$ was added in the artificial seawater, but 92.4% of turbidity removal was observed when 0.05g/L of PGA was added in the artificial seawater containing microalgae. In addition, much greater turbidity removal was achieved for microalage than sediments. For both cases, input of 0.1g/L PGA and following additional input of micro-air bubbles for 5 seconds resulted in the maximum removal efficiency where reaction time of coagulation was 1 min and flotation by micro-air bubbles was 10 min. From this study, we concluded that micro-air floation after coagulation could be a possible economical pre-treatment method for highly turbid seawater.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.151-151
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• 2012

A new plasma process, i.e., the combination of PIII&D and HIPIMS, was developed to implant non-gaseous ions into materials surface. HIPIMS is a special mode of operation of pulsed-DC magnetron sputtering, in which high pulsed DC power exceeding ~1 kW/$cm^2$ of its peak power density is applied to the magnetron sputtering target while the average power density remains manageable to the cooling capacity of the equipment by using a very small duty ratio of operation. Due to the high peak power density applied to the sputtering target, a large fraction of sputtered atoms is ionized. If the negative high voltage pulse applied to the sample stage in PIII&D system is synchronized with the pulsed plasma of sputtered target material by HIPIMS operation, the implantation of non-gaseous ions can be successfully accomplished. The new process has great advantage that thin film deposition and non-gaseous ion implantation along with in-situ film modification can be achieved in a single plasma chamber. Even broader application areas of PIII&D technology are believed to be envisaged by this newly developed process. In one application of non-gaseous plasma immersion ion implantation, Ge ions were implanted into SiO2 thin film at 60 keV to form Ge quantum dots embedded in SiO2 dielectric material. The crystalline Ge quantum dots were shown to be 5~10 nm in size and well dispersed in SiO2 matrix. In another application, Ag ions were implanted into SS-304 substrate to endow the anti-microbial property of the surface. Yet another bio-application was Mg ion implantation into Ti to improve its osteointegration property for bone implants. Catalyst is another promising application field of nongaseous plasma immersion ion implantation because ion implantation results in atomically dispersed catalytic agents with high surface to volume ratio. Pt ions were implanted into the surface of Al2O3 catalytic supporter and its H2 generation property was measured for DME reforming catalyst. In this talk, a newly developed, non-gaseous plasma immersion ion implantation technique and its applications would be shown and discussed.

• Journal of Life Science
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• v.22 no.7
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• pp.863-870
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• 2012

Rhodopsin, a dim light photoreceptor, has been regarded as one of the model systems for the structural and functional study of G protein-coupled receptors (GPCRs). Constitutively active mutant GPCRs leading to the activation of heterotrimeric GDP/GTP-binding protein signaling in the absence of ligand binding are of interest for the study of the activation mechanism in GPCRs. The present study focused on the opsin mutant E134Q/M257Y, which showed a moderate level of constitutive activity and the formation of two distinct rhodopsin chromophores with absorption maxima of 500 nm and 380 nm, depending on the presence of an inverse agonist, 11-cis-retinal, and an agonist, all-trans-retinal, respectively. Reconstitution of the mutant rhodopsin upon incubation with different ratios of 11-cis-retinal and the all-trans-retinal, as well as upon sequential binding of the two retinals, indicated its preferential binding to 11-cis-retinal. The thermal stability of the 11-cis-retinal-bound form of the E134Q/M257Y mutant was lower than that of the mutants containing a single replacement but higher than that of the all-trans-retinal-bound forms. The mutant also showed a lower stability in its opsin state as compared with that of the wild-type opsin but had little effects on the binding affinity to 11-cis-retinal. Information obtained in this study will be helpful for analyzing the structural changes associated with the activation of rhodopsin and GPCRs.

• Journal of Life Science
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• v.22 no.7
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• pp.958-963
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• 2012

The antioxidant activities of 6 solvent extracts of Artemisia capillaris were evaluated in a dintroflurobenzen (DNFB)-induced allergic mouse model. In vitro antioxidant activities were determined using DPPH and the FRAP test. Methanol (DPPH: 85.87%, FRAP: 1.772) and $dH_2O$ (DPPH: 60.69%, FRAP: 3.185) extracts showed the highest antioxidant activities compared with other solvents (ethyl acetate 41.81%, 0.407, hexane 8.37%, 0.328, etc.). In addition, we tested atopic dermatitis (AD)-like skin lesions in mice treated with DNFB. The methanol extract of A. capillaris on the AD-like skin lesions in DNFB-induced atopy inhibited ear thickness increases (47%) and the skin lesions (45%) compared with a positive control (methanol). The results suggest that they have potential as natural antioxidants and allergy-improving substances and that they may be valuable materials in the functional food or cosmeceutical industry.

• Journal of the Korean Wood Science and Technology
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• v.40 no.3
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• pp.177-185
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• 2012

The interest to develop adhesives from renewable resources is growing to substitute petroleum-based adhesive resins in the manufacture of wood based panels. In our study, rapeseed flour (RSF), which is the by-product of bio-diesel produced from rapeseed, were hydrolyzed with acid and alkali. As a crosslinking agents of the RSF hydrolyzates, phenol-formaldehyde prepolymers (PF) were prepared. The RSF hydrolyzates and PF were mixed to complete the formulation of RSF-based adhesive resins, and the resins were applied to make the medium density fiberboard (MDF). The physical and mechanical properties of the MDF were measured to examine whether RSF can be used as raw materials of adhesive resins for the manufacture of MDF or not. The average moisture content and density of the MDF made with RSF-based adhesive resins satisfied the minimum requirement of KS standard, but the thickness swelling was not. The bending strengths of the MDF made with RSF-based adhesive resins were lower than that of the MDF made with commercial UF resins, but the internal bonding strengths of tested MDF in some make-up conditions of RSF-based adhesive resins were higher than that of MDF made with commercial UF resins. These results showed the potential of RSF as a raw material of adhesives for the production of MDF. Future works on the optimal manufacturing process conditions of MDF made with RSF-based adhesive resins are required to improve the performance of MDF made with RSF-based resins.

• Clean Technology
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• v.19 no.2
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• pp.148-155
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• 2013

Volatile fatty acids (VFAs) production from marine brown algae, Saccharina japonica, was investigated in anaerobic dark fermentation. In order to evaluate the VFAs productivity, various experimental parameters (i.e., physicochemical pre-treatment, microorganism inoculation ratio, substrate concentration, and pH) were evaluated. According to the physicochemical pre-treatment methods, the maximum concentrations of VFAs were obtained in the order of sulfuric acid, subcritical water and subcritical water with lipid-extraction. Also, we investigated the operating parameters such as microorganism inoculation ratio (MV/M = 10 to 30), the substrate concentration (18.0 to 72.0 g/L) and pH (6.0 to 7.0) in sulfuric acid pre-treatment method. When the substrate concentrations were 18.0, 36.0, 54.0 and 72.0 g/L at $35^{\circ}C$, microorganism inoculation ratio 15, pH 7.0 for 372 hours, the maximum concentrations of VFAs were respectively 9.8, 13.9, 18.6 and 22.3 g/L. The change in VFAs concentrations was detected that acetic- and propionic acids increased according to increasing pH, while the butyric acid increased with decreasing pH. The VFAs obtained from concentration and separation process may be used as basic chemistry materials and bio-fuel, and they will expect to produce alternative energy of fossil fuel.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.504-510
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• 2016

This study was investigated to find the effects of sowing time on growth and yields of cowpea grown in a southern region of South Korea. Experiments were carried out in Naju, Jeonnam Province (Latitude 35° 04' N, Longitude 126° 54' E) during 2013 and 2014. The intermediate-erect type strains used in this study were Jeonnam1 and Jeonnam2 (Okdang). Sowing time was performed between middle-April and middle-August at intervals of one month. The days from sowing to emergence was significantly higher in the middle-April sowing (12 days) time but there was no significant differences other sowing dates (5 to 3 days). The days from sowing to first flowering were shorter for sowing dates between middle-April and middle-July because sowing time was delayed and then were lengthened again at middle-August sowing; the days were longest at middle-April sowing (around 62 days) and were shortest at middle-July sowing (35 days). The days from first flowering to harvesting were short for the sowing dates between middle-April and middle-July (17 to 15 days) but were relatively long for middle-August sowing date (24 days). Stem length was relatively long for the middle-May and middle-June sowing dates. Peduncle length was relatively long for the middle-April sowing date. Main-stem node number was highest for the middle-July sowing. Branch number per plant was highest in the middle-April sowing. Seed yields were highest for the middle-April sown Jeonnam1 and the Jeonnam2 (Okdang) strains showing, 199 and 211 kg/10a, respectively, and then followed by sowing in middle-July, 191 and 195 kg/10a, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.418-424
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• 2017

Magnesium has a higher specific strength than other metals and is widely used industry wide due to its excellent vibration absorption ability and electromagnetic wave shielding property.For example, it is used for automobile parts such as car seat frames and cylinder heads, and is widely used in electronic products such as notebook cases and mobile phone cases. In addition, it is in the spotlight as a bone-implant material used to assist in the treatment of damaged bones when the bones are cracked or broken. Currently, Ti alloy, stainless steel and Co-Cr-Mo alloy are used as the implant material, and the Mg alloy remains in research stage. The current problem with bone implant implants is that the patients must undergo reoperation to remove the implants after joint surgery. Magnesium, however, can achieve sufficient strength compared to current materials. In addition, since it is self-decomposed after the recovery, reoperation is not necessary. In this paper, Mg alloys were designed by adding harmless Ca and Zn to the human body. In order to improve the strength and corrosion resistance, the final alloy was designed by adding a small amount of Sr as a grain refiner. The radioactive elements of Sr are harmful to the human body, but other naturally occurring Sr elements are harmless. Microstructure analysis of the alloys was performed by optical microscopy and scanning electron microscopy. The mechanical properties and corrosion characteristics were evaluated by tensile test, potentiodynamic test and immersion test.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.620-625
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• 2015

In an effort to reduce the onset of global warming, the International Maritime Organization Marine Environment Protection Committee (IMO MEPC) proposed the reduction in ship speeds as a way of lowering the proportion of carbon dioxide ($CO_2$) in the Green House Gas emissions from ships. To minimize fuel costs, shipping companies have already been performing slow steaming for their own fleets. Specifically, the slow steaming approach has been adopted for most ocean-going container lines. In addition, because of the increased marine fuel cost that is required to enable increased capacity, there is an urgent need for more advanced fuel-saving technologies. Therefore, in this present study, we propose a fuel-cost reduction method that can improve the performance of diesel engines. We introduce a predetermined amount (0.025% of the amount of fuel used) of fuel additive (oil-soluble calcium-based organometallic compound). For improved experimental accuracy, as the test subjects, we utilize a large two-stroke diesel engine installed in land plants. The loads of the test engine were classified as low, medium, and high (50, 75, and 100%, respectively). We compare the engine performance parameters (power output, fuel consumption rate, p-max, and exhaust temperature) before and after the addition of fuel additives. Our experimental results, confirmed that we can realize fuel-cost savings of at least 2% by adding the fuel additive in low load conditions (50%). Likewise, the maximum combustion pressure was found to have increased. On the other hand, we observed that there was a reduction in the exhaust temperature.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.267-274
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• 2015

Biopharmaceuticals and the cell substrates used for their manufacture are currently tested for porcine adventitious viruses due to the widespread use of porcine trypsin in cell culture. Porcine transmissible gastroenteritis virus (PTGV) is one of the major adventitious porcine viruses causing contaminated during the manufacture of biopharmaceuticals. Therefore, rapid and sensitive detection of PTGV is essential in ensuring the safety of biopharmaceuticals. A TaqMan probe real-time RT-PCR method was developed for the quantitative detection of PTGV contamination in cell substrates, raw materials, manufacturing processes, and final products, as well as PTGV clearance validation. Specific primers for the amplification of PTGV RNA were selected, and PTGV RNA was quantified by use of a specific TaqMan probe. Specificity, limit of detection (LOD), and robustness of the method was validated according to international guidelines on the validation of nucleic acid amplification tests. The sensitivity of the assay was calculated to be 1.10 × 10⁰ TCID₅₀/ml. The real-time RT-PCR method was validated to be reproducible, very specific to PTGV, and robust. The established real-time RT-PCR assay was successfully applied to the validation of Chinese Hamster Ovary (CHO)-K1 cells artificially infected with PTGV.