• Korean Journal of Microbiology
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• v.48 no.3
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• pp.187-191
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• 2012

Two-component system (TCS)-based bacterial zinc and copper biosensors, in which green fluorescent protein (GFP) is expressed under the control of zraP and cusC promoter in ZraS/R and CusS/R TCS, were evaluated in artificial wastewater. Bacterial biosensors developed in this study efficiently expressed GFP by the recognition of $Zn^{2+}$ and $Cu^{2+}$ in artificial wastewater. Secondly, TCS-based zinc and copper removing bacteria with the peptide displayed on cell surface were examined in artificial wastewater. Zinc and copper removing bacteria expressed the peptide as a fusion protein such as OmpC-ZBP (zinc binding peptide) and OmpC-CBP (copper binding peptide) on the cell surface when sensing exogenous $Zn^{2+}$ and $Cu^{2+}$ through ZraS/R and CusS/R TCS. The recombinant cell expressing metal-adsorbing peptide could efficiently remove copper and zinc (15 and 18 mg/g dry cell weight, respectively) in artificial wastewater. Therefore, it was demonstrated that the TCS-based recombinant cell for the recognition or removal of heavy metal functions well in artificial wastewater environment.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1296-1299
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• 2013

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.131-132
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• 2005

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1703-1706
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• 2004

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.3
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• pp.183-188
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• 2001

The deposition behavior and photoelectric response characteristics of chlorophyll a(Chl a) monolayers and multilayers were investigated under various film fabrication conditions. Chl a LB films were deposited onto quartz and pretreated ITO glass substrates under several fabrication conditions, including surface pressure and number of layers. The absorption spectra of Chl a in a solution state and solid-like state (LB films) were fairly consistent with each other, and two absorption peaks were found at 678 and 438nm, respectively. The prepared Chl a LB films were set into an electrochemistry cell equipped with a Pt plate as the counter electrode, and the photoelectric response characteristics were obtained and analyzed relative to the light illumination. By considering the resulting photocurrents, the optimal fabrication conditions for Chl a LB films were determined as 20mN/m of surface pressure and 20 layers. The action spectrum of the Chl a LB films was obtained in the visible region, and was found to be in good agreement with the absorption spectrum. The possible application of the proposed system as a constituent of an artificial color recognition device was suggested based on combining with the photoelectric conversion property of another light-sensitive biological pigment.

• Journal of the Korean Ceramic Society
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• v.51 no.2
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• pp.57-63
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• 2014

Bottom ash can be used as pelletizing seeds in unsintered artificial lightweight aggregates, so it can be called as 'cold-bonded aggregates'. In the present study, the mechanical and chemical characteristics of bottom ash aggregates cold-bonded with fly ash were investigated. The crushing strength and the water transfer characteristic of the aggregates, which may affect the strength gain of the concrete, were evaluated. Moreover, the degree of hydration and the hydration products of the aggregates were analyzed to verify the chemical stability of the aggregates. Compared to commercialized artificial lightweight aggregates manufactured by sintering process, cold-bonded fly/bottom ash aggregates had similar levels of water transfer characteristics, while having lower strengths. The calcium hydroxide in the aggregates was almost completely consumed after 28 days moist curing.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.4
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• pp.309-320
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• 2007

Purpose: This study was to evaluate the removal effect on artificial plaque from RBM treated implant surfaces that are exposed due to peri-implantitis. Materials and methods: Artificial plaque with Streptococcus mutans and acquired pellicle adhered to RBM treated implant discs. Study materials divided into one control and six test groups. In test groups, physical and chemical methods used to remove plaques. Prophyflex, Professional Mechanical Tooth Cleaning (PMTC) and interdental brush as mechanical treatments and 0.1% Chlorhexidine, Citric acid, HCl tetracycline as a chemical treatment were used. To analyses the study, disc weight was measured for remaining plaque quantities and SEM(Scanning Electronic Microscope) findings was taken for evaluation of surfaces. Results: 1. In weight changes, there was significant difference between each treatment group and the control group (p<0.05). Therefore all treatment methods using this study have good ability for remove plaques. 2. In weight changes, there was no significant difference between mechanical and chemical group, and there were no significant differences between each groups (p>0.05). 3. SEM findings after mechanical treatment disclosed as follows; Prophyflex group looked like sound implant surface, and there were some paste on implant surface at PMTC group, and there were some artificial plaque at interdental brush group. 4. SEM findings after chemical treatment disclosed as follows; there were some dark lesions which were supposed as the product from Streptococcus mutans at Chlorhexidine, Citric acid and HCl tetracycline groups. Conclusion: All six methods using in this study have good ability to remove artificial plaque on RBM treated implant. According to SEM findings, prophyflex is a superior method for removing of dental plaque among test groups.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.542-549
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• 2023

Since the growing interest in surrogate modeling, there has been continuous research aimed at simulating nonlinear chemical processes using data-driven machine learning. However, the opaque nature of machine learning models, which limits their interpretability, poses a challenge for their practical application in industry. Therefore, this study aims to analyze chemical processes using Explainable Artificial Intelligence (XAI), a concept that improves interpretability while ensuring model accuracy. While conventional sensitivity analysis of chemical processes has been limited to calculating and ranking the sensitivity indices of variables, we propose a methodology that utilizes XAI to not only perform global and local sensitivity analysis, but also examine the interactions among variables to gain physical insights from the data. For the ammonia synthesis process, which is the target process of the case study, we set the temperature of the preheater leading to the first reactor and the split ratio of the cold shot to the three reactors as process variables. By integrating Matlab and Aspen Plus, we obtained data on ammonia production and the maximum temperatures of the three reactors while systematically varying the process variables. We then trained tree-based models and performed sensitivity analysis using the SHAP technique, one of the XAI methods, on the most accurate model. The global sensitivity analysis showed that the preheater temperature had the greatest effect, and the local sensitivity analysis provided insights for defining the ranges of process variables to improve productivity and prevent overheating. By constructing alternative models for chemical processes and using XAI for sensitivity analysis, this work contributes to providing both quantitative and qualitative feedback for process optimization.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.5
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• pp.107-115
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• 2002

This study was carried out to compare artificial soil formulated by blending calcined clay and coconut peat with perlite, then to evaluate this soil as a perlite substitute for use as an artificial planting medium. To achieve this, a determination of the physico-chemical properties and it's effect on plant growth were conducted by comparing those with large perlite grains and small grains. The results are summarized as follows: 1) The bulk density was 0.41g/㎤. This density was lower than that of field soil, but higher than that of large perlite grain(0.23g/㎤) and small grain(0.25g/㎤). The porosity, field capacity, and saturated hydraulic conductivity were 71.3%, 49.2%, and 3.8$\times$10-2cm/s, respectively. The air-permeability, water holding capacity, and drainage were better than or equal to that both large and small perlite grain. 2) It was near-neutral in reaction(pH=6.6). It had a high organic carbon content(65.8g/kg) and a low available phosphoric acid content(84.7mg/kg). It was similar to crop soil in cation exchange capacity(11.4cmol/kg). It had a low exchangeable calcium content(0.71cmol/kg), a low exchangeable magnesium content(0.68cmol/kg), a high exchangeable potassium content(2.54cmol/kg), and a high exchangeable sodium content(1.12cmol/kg). Except for the exchangeable potassium and sodium content, the chemical properties were better than or equal to both large and small grain perlite. The excessive exchangeable potassium or sodium content will inhibit plant growth. 3) In Experiment 1, the plant growth tended to be higher compared to that of large and small perlite gains. But in Experiment 2, it tended to be lower. This might be linked to the excessive exchangeable potassium or sodium content. 4) It could be considered as a renewable perlite substitute for greening of artificial soil. But, it would be necessary to leach the excessive exchangeable potassium or sodium to avoid the risk of inhibiting plant growth.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.5
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• pp.59-69
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• 2000

Sludge is generated in the process of water and wastewater treatment, and it has been causing various environmental problems. From this point of view, recycling of sludge appears to be the best way. The firing technology in pottery industry is applied to the sludge treatment , and the final product is called artificial soil. The effect of mixed artificial soil with upland soil was investigated through the crop growth experiment and the physical & chemical characteristics of the mixed soils were analyses. After the growth experiment , mixed soil plots contained more CEC, OM, TN, TP than upland soil plots. This result shows that the artificial soil produced form sludge can be mixed with upland soil, and crop can be increased. From the growth analysis, growth of soybean and corn in the mixed soil plots was better than that in the original upland soil plots. Heavy metals contents in the mixed soil plots were within the quality standard. This is a promising result since in most cases heavy metals are the most concern in the application of sludge product to farmland.