• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.403-408
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• 2012

Gelatin/Ag nanoparticle (AgNP) biocomposite was synthesized using the solution plasma process (SPP) that has been recently introduced as an effective method for synthesis of nanoparticles. In this study, gelatin/AgNP biocomposite was synthesized using various concentrations of Ag precursor ($AgNO_3$) and gelatin in the range of 1-5 mM and 1-3% (w/w), respectively, without using any chemical reducing agent. Physical properties of the gelatin/AgNP biocomposites were analyzed using EDS, FE-SEM, and TEM. The results indicated that spherical AgNPs with approximately 12~20 nm in diameter were synthesized successfully in the gelatin matrix by SPP. As the concentration of gelatin was increased (3%, w/w), disperse stability of AgNP was improved and micro-pores of gelatin became smaller and denser in the 3D scaffold. Bactericidal activity of the AgNPs was examined against Staphylococcus aureus and Escherichia coli by measuring zone of growth inhibition and decrease in colony forming unit (CFU). CFUs of S. aureus and E. coli were decreased approximately to 56% and 0%, respectively, by the gelatin/AgNP biocomposite, Ag5G3.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.18-23
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• 2006

Foaming of slag is a thermodynamically unstable phenomenon and has significant effects in iron and steelmaking processes. For better recycling method of pulp sludge, the application as an defoaming agent during steelmaking process was adopted and tested. The forming machine has been modified in order to produce the briquettes, which are made of pulp sludge and slag with different weight ratio. Influencing factors on the foaming phenomena have been studied and tested for better understanding of foaming phenomena. Experiments were carried out with $CaO-FeO-SiO_2$ based slags with Ar gas injection and addition of coke particles. The slag basicity and (%FeO) contents adapted as major factors to treasure foaming tendency of the slag system. It was found that foam index (${\Sigma}$) gradually decreased as both the basicity and the (FeO) content increase. Four kinds of antifoaming agent such as aluminium dross, cokes, rice bran and pulp sludge with steelmaking slag have been tested in actual process. Aluminium dross was the most effective, and pulp sludge with steelmaking slag also showed the desired results.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.3 s.58
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• pp.201-208
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• 2006

Propionibacterium acnes have been recognized as pus-forming bacteria triggering an inflammation in acne. The present study was conducted to evaluate antimicrobial activities of Dryopteris crassirhizoma Nakai against these etiologic agents of acne vulgaris and application possibility as a cosmetic resource. D. crassirhizoma crude extract and hexane fraction was prepared and its anti-acne effect against Propionibacterium acnes was investigated with minimum inhibitory concentration (MIC) and paper disk diffusion method. The MIC of D. crassirhizoma crude extract and hexane fraction was 0.008 mg/mL and 0.001 mg/mL, respectively. This implies that D. crassirhizoma extract may be an efficient anti-acne ingredient for cosmetics, as a crude extract. The paper disk diffusion assay showed that its anti-acne effect was similar to that of triclosan. The cytotoxic effect of D. crassirhizoma extract was determined by a colorimetric MTT assay using HaCaT cell line and D. crassirhizoma extract exhibited lower cytotoxic effects. Finally, we examine the stability of D. crassirhizoma extract to temperature and pH. The D. crassirhizoma extract was very stable to high temperatures ($25{\sim}121^{\circ}C$) and to wide pH range ($pH\; 2{\sim}11$), suggesting its utilization for cosmetics.

• Journal of the Korean Vacuum Society
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• v.21 no.1
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• pp.12-16
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• 2012

Although silver is used for T-OLED (Top emitting organic Light-Emitting Diode) as reflective anode, it is not an ideal material due to its low work function. Thus, we study the effect of annealing and atmospheric pressure plasma treatment on Ag film that increases its work function by forming the thin silver oxide layer on its surface. In this study, we deposited silver on glass substrate using RF sputtering. Then we treated the Ag samples annealing at $300^{\circ}C$ for 30 minutes in atmosphere or treating the atmospheric plasma treatment for 30, 60, 90, 120s, respectively. We measured the change of the mechanical properties and the potential value of surface with each one at a different treatment type and time. We used nano-indenter system and KPFM (Kelvin Probe Force Microscopy). KPFM method can be measured the change of surface potential. The nanoindenter results showed that the plasma treatment samples for 30s, 120s had very low elastic modulus, hardness and Weibull modulus. However, annealed sample and plasma treated samples for 60s and 90s had better mechanical properties. Therefore, plasma treatment increases the uniformity thin film and the surface potential that is very effective for the performace of T-OLED.

• Food Science and Preservation
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• v.16 no.3
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• pp.321-326
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• 2009

We assessed quality changes in and washing effects (time and method) on lettuce (Lactuca sativa L.) treated with micro-bubbles. Samples were treated with micro-bubbling for 1, 3, or 5 min, and the 5-min treatment yielded the best results in terms of reduced total microorganism counts, sensory aspects, and degree of washing. Total microorganism counts were 4.30 log colony-forming units (CFU)/g in unwashed lettuce(CT), 4.10 log CFU/g in hand-washed lettuce (HW), 3.98 log CFU/g in conventional, bubble-washed lettuce (BW) and 3.25 log CFU/g in micro-bubble-washed lettuce (MW). In comparison, total counts of samples examined after 10 days of storage were 7.00 log CFU/g for CT, 6.19 log CFU/g for HW, 6.02 log CFU/g for BW, and 5.89 log CFU/g for MW. The lowest counts were seen after micro-bubble treatment. BW and MW samples showed significantly higher counts than did CT and HW samples. In general, BW and MW samples did not vary significantly in count numbers. MW showed a 2.3-fold lower residual pesticide level compared with CT, and also had the lowest level of impurities. HW and BW samples were not well washed.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.313-321
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• 2014

In current society, the digital era that makes enormous amount of data, and the diversified city, the smart space, which has characteristics of creating, collecting and representing data, is appeared. After 2012, in the social media environment called hyper-connected society with wide-spread smart phone, people started to get interested in public data and big data by generalized mobile device and SNS. At first, development of forming platform of data was focused, but now, many different idea from diverse area have been suggested about data analysis and usage to visualize the space intellectualization service. To focus on the visualization process to increase the usage of this public data for ordinary people more than specialized people, this research grasps the present condition of open data and public data service from the current public data portal and considers the applicability of them. As the result of research, the analysis and application of data to ordinary people decrease the use of paper documents, and this research will help to develop the application which is fast and accurate about individual behavior and demand to utilize public data service in intellectual space.

• Journal of the Korean Geographical Society
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• v.45 no.1
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• pp.95-118
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• 2010

This study aims to investigate the spatial distribution of major soil types in Korea, and to assess the ability to predict soil distribution using environmental variables. A classification tree method was used to assess soil predictability. While the great soil groups can give more intuitive understandings on their spatial distributions, its predictability using environmental factors is much lower than that of the great groups. The most important factor to determine the spatial distribution of major soil types is the geomorphological characteristic of Korea that shows distinctive morphological difference between mountains and plains. Spatial distribution of climatic variables and catenary soil sequence along slopes play additional roles in determining the distribution of soil types. The classification tree models resulted in 35-75% of prediction accuracy, depends on the combination of different environmental variables brought in the models. While geomorphological variables are the best predictors for the great groups, climatic variables perform better for the great soil groups.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.758-764
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• 2003

The cylindrical ${\gamma}$-alumina pellets were prepared by forming, hydration, drying and calcination after mixing amorphous alumina and pore generating agent with water. Concentration of Fe(NO$_3$)$_3$ㆍ9$H_2O$ that was catalyst precursor was fixed and made mixing solution that changed concentration of $CH_3$COOH in range of 2.5~20%, and here ${\gamma}$-alumina pellets were immerged and were hydrothermaly treated for 3 h at $200^{\circ}C$. And then we investigated creation and change of crystal, pore characteristics, $N_2$ adsorption and desorption isotherms, changes of acid site and mechanical strengths etc. According to the concentration of $CH_3$COOH, the crystals grew to acicular shape of 0.5~2${\mu}m$ length, and crystal structure showed the pseudo-boehmite structure. When hydrothermaly treated in 10% $CH_3$COOH solution, pore volume between 100~1000 $\AA$ was highest by 0.86 cc/g, and width of hysteresis curved line due to $N_2$ adsorption/desorption appeared as was smallest. When concentration of $CH_3$COOH was in range of 5~15%, new C-H functional groups were formed. Mechanical strength of pellets was highest by 1.35 MPa when $CH_3$COOH concentration was 2.5%.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.506-525
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• 2007

Incision into bedrock channel is the primary control of landform evolution, but research into bedrock incision process stagnated for long time. Due to the scaling problem of the application of results from flume studies to bedrock channel, there is a strong need to simulate the bedrock incision process with more realistic models. As a part of investigation into controls of bedrock channel incision, three-dimensional changes of rock surface with abrasion was investigated with physical modelling. 18 rock plates were abraded with various sediment particle size and sediment load and abraded surfaces of the plates were scanned with high resolution 3-D scanner. To identify the spatial pattern of erosion of the rock plates, various methods were used. There was no synthetic or holistic method that showed all features of bedrock plate produced by abrasion, so each plate was analyzed using some available methods. Contour maps, shaded relief maps and profiles show that abrasion concentrated on the centre of plate (cross profile) and upstream and downstream edges (longitudinal profile) and eroded area extended inwards. It also found that the cracks and boundaries of forming materials easily eroded than other parts. Changing patterns of surface roughness were investigated with profiles, regression analysis and spectral analysis. Majority of plates showed decrease in small-scale roughness, but it depends on microstructures of the plates rather than general hardness or other factors. SEM inspection results supported this idea.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.453-460
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• 2004

To prevent penetration of rainwater into the landfill site is the main purpose of the final cover in landfill sites. Conventional designs of landfill covers uses geotextiles such as geomembrane and GCL, and clay liners to lower the permeability of final covers of landfill sites. However, differential settlement and the variation of temperature in landfill sites cause the development of cracks or structural damage inside the final cover and it is also difficult to obtain clay - the main material of the compacted clay liner in Korea. Thus the former final cover system that suggests geomembrane and GCL or compacted clay liner has several limitations. Therefore, an alternative method is necessary and one of them is the application of SRSL(self-Recovering Sustainable Liner) material. SRSL is two different layers consist of individual materials that react with each other and form precipitates, and with this process lowers the permeability of the landfill final cover. SRSL generally is made up of two layers, so that when a internal crack occurs the reactants of the two layers migrate towards the crack and heal it by forming another liner. In this study the applicability of SRSL material for landfill final cover was examined by performing; (1) jar test to verify the formation of precipitate in the mixture of each reactants, (2) falling head test considering the field stress in order to confirm the decrease of permeability or prove that the hydraulic condctivity is lower than the regulations, (3) compression tests to judge weather if the strength satisfies the restricts for landfills, (4) freeze/thaw test to check the applicability of SRSL for domestic climate. In addition, the application of waste materials in the environmental and economical aspect was inspected, and finally the possibility of secondary contamination due to the waste materials was examined by performing elution tests.