• Clean Technology
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• v.18 no.4
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• pp.331-340
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• 2012

Synthetic methods of colloids have been significantly developed in industry due to their significant demand for preparation of functional particles. Recently, dynamic/static microfluidic system has emerged as a promising route to the synthesis of the particles, providing precise control of physical and chemical properties such as size, shape, porosity, surface roughness, and surface functionality. These formed particles can be potentially used in various applications including medical diagnostics, photonic device, and biological industry. In addition, these particles provide a novel route to create new materials via their directed self-assembly, and it enable to study and predict the natural phenomenon by mimicking of the nature. Therefore, we describe recent progress for functional colloid particles and its applications.

• Korean Journal of Plant Resources
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• v.25 no.4
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• pp.372-378
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• 2012

Xanthium sibiricum using extracts antioxidant activity and antimicrobial activity were analyzed and the following results were obtained. Antioxidant activity using DPPH as a VLC column fractionation experiments XS-5 (water fraction of Xanthium sibiricum) concentration in the 500 ${\mu}g/ml$ to 87.53 percent in the highest antioxidant activity was found, VLC fractionation in XS-3-2 (eluted with chloroform/methanol 7~10%) concentration of 500 ${\mu}g/ml$, showed the antioxidant activity of 78.72%. The antioxidant activity measured by PCL XS-1 (n-hexane fraction of Xanthium sibiricum) XS-5 (water fraction of Xanthium sibiricum) and 13.32 nmol open column XS-3-2 (eluted with chloroform/methanol 7~10%) showed antioxidant activity with 14.34 nmol. The antimicrobial activity against Candida albicans XS-2 (methlene chloride fraction fo Xanthium sibiricum) is the concentration of 500 ${\mu}g$/disc 1 mm of the clean zone was formed. XS-3 (ethanol fraction fo Xanthium sibiricum) in the antioxidant activity using DPPH and PCL had higher antibacterial activity was low.

• Journal of the Korean Institute of Gas
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• v.19 no.5
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• pp.7-12
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• 2015

Hydrogen is usually produced by using syngas generated by the fuel reforming for natural gas so far. The further process is needed for increasing the hydrogen yield of syngas. However, the process for upgrading the hydrogen yield is accompanied by additional energy sources and economic costs. Thus related studies on the method for using as a mixture in itself have been conducted in order to utilize more efficiently syngas. The effect on the engine performance for methane/syngas mixture of 30kW spark ignition gas engine for power generation has been investigated in this study. As a result, it was found that the combustion phenomena such as the maximum in-cylinder pressure and crank angle at that time have been improved by methane/syngas mixture. Through these, fuel conversion efficiency could be enhanced by about 98% of methane/hydrogen mixture and $NO_x$ emissions could be reduced by about 12% of methane-hydrogen mixture.

• Clean Technology
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• v.28 no.2
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• pp.97-102
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• 2022

Lithium sulfur (Li-S) batteries have attracted considerable attention as a promising candidate for next-generation power sources due to their high theoretical energy density, low cost, and eco-friendliness. However, the poor electrical conductivity of sulfur and its insoluble discharging products (Li₂S₂/Li₂S), large volume changes, severe self-discharge, and dissolution of lithium polysulfide intermediates result in rapid capacity fading, low Coulombic efficiency, and safety risks, hindering Li-S battery commercial development. In this study, a three-dimensionally (3D) connected hierarchical porous carbon framework (HPCF) derived from waste sunflower seed shells was synthesized as a sulfur host for Li-S batteries via a chemical activation method. The natural 3D connected structure of the HPCF, originating from the raw material, can effectively enhance the conductivity and accessibility of the electrolyte, accelerating the Li⁺/electron transfer. Additionally, the generated micropores of the HPCF, originated from the chemical activation process, can prevent polysulfide dissolution due to the limited space, thereby improving the electrochemical performance and cycling stability. The HPCF/S cell shows a superior capacity retention of 540 mA h g^-1 after 70 cycles at 0.1 C, and an excellent cycling stability at 2 C for 700 cycles. This study provides a potential biomass-derived material for low-cost long-life Li-S batteries.

• Journal of Forest and Environmental Science
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• v.33 no.2
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• pp.113-121
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• 2017

In flight particulate matter particularly emissions generated by incomplete combustion processes has become a subject of global concern due to the health problems and environmental impacts associated with them. This has compelled most countries to set standards for coarse and fine particles due to their conspicuous impacts on environment and public health. This contribution therefore explores forest fire emissions and how its particulates affects air quality, damage to vegetation, water bodies and biological functions as architects for lung diseases and other degenerative illnesses such as oxidative stress and aging. Soot was collected from simulated forest fire using a clean glass surface and carefully transferred into amber vials for analysis. Volatile components of soot were collected over 10 mL dichloromethane and analyzed using a QTOF Premier-Water Corp Liquid Chromatography hyphenated to a mass selective detector (MSD), and Gas Chromatograph coupled to a mass spectrometer (GC-MS). To characterize the size and surface morphology of soot, a scanning electron microscope (SEM) was used. The characterization of molecular volatiles from simulated forest fire emissions revealed long chain compounds including octadec-9-enoic acid, octadec-6-enoic acid, cyclotetracosane, cyclotetradecane, and a few aromatic hydrocarbons (benzene and naphthalene). Special classes of organics (dibenzo-p-dioxin and 2H-benzopyran) were also detected as minor products. Dibenzo-p-dioxin for instance in chlorinated form is one of the deadliest environmental organic toxins. The average particulate size of emissions using SEM was found to be $11.51{\pm}4.91{\mu}m$. This study has shown that most of the emissions from simulated forest fire fall within $PM_{10}$ particulate size. The molecular by-products of forest fire and particulate emissions may be toxic to both human and natural ecosystems, and are possible precursors for various respiratory ailments and cancers. The burning of a forest by natural disasters or man-made fires results in the destruction of natural habitats and serious air pollution.

• Korean Journal of Environmental Agriculture
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• v.29 no.3
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• pp.257-265
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• 2010

In this study, the residual levels of four insecticidal compounds (lambda-cyhalothrin, lufenuron, thiamethoxam, and clothianidin) were monitored in the pomegranate, in order to assess the risk to consumers posed by the presence of such residues. The insecticides were applied at the recommended dose rates onto pomegranate trees. The samples were then collected at harvesting time after several treatments (two, three, and four treatments). After sample preparation progressed through the clean-up procedure, lufenuron, thiamethoxam, and clothianidin residues were analyzed via a HPCL-UVD, and the lambda-cyhalothrin residue was analyzed via a GC-${\mu}ECD$. The versatility of this method was evidenced by its excellent linearity (>0.9998 to 1) at broad concentration ranges. The mean recoveries evaluated from the untreated sample spiked with two different fortification levels ranged from 72.45 to 113.90%, and the repeatability (as a relative standard deviation) resulted from triplicate recovery tests was in a range from 0.80 to 11.75%. The residues of all insecticides determined from treated pomegranate samples and their LOD levels (lunfenuron, 0.01; lambda-cyhalothrin, 0.005; thiamethoxam, 0.01; clothianidin, 0.02 mg/kg) were much lower than their MRLs (0.5 mg/kg).

• Proceedings of the Microbiological Society of Korea Conference
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• 2002.10a
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• pp.100-105
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• 2002

The diversity of epiphytic bacterial communities on deciduous oak tree (Quercus dentate Thunb.) leaves was examined both in the natural forest area with a clean air and in the industrial estate to assess effects of acidic deposition to the phyllosphere using 16S rDNA sequence data. In addition, acid-tolerant epiphytic bacterial communities were compared. A total of 78 epiphytic and 444 acid-tolerant clones were obtained from clone libraries, resulting in 20 and 17 phylotypes by analysis of restriction fragment length polymorphism (RFLP) for PCR-amplified 16S rDNA products. A low bacterial diversity in both areas was found. As tree leaves grow older, bacterial diversities were slightly increased in the level of subphylum. The community structure of epiphytic bacteria in both areas in April consisted of only two subphyla, $\beta-and\;\gamma-Proteobacteria$. In August two additional subphyla in both areas were found, but the composition was a little different, Acidobacteria and Cytophaga-Flexibacter-Bacteroids (CFB) group in the industrial estate and a -Proteobacteria and CFB group in the natural area, respectively. Acidobacteria could be an indicator of epiphytic bacteria for acidic deposition on plant leaves, whereas a -Proteobacteria be one of epiphytic bacteria that naturally survive on leaves that are not affected by acidic deposition. The acid-tolerant bacterial communities in April were composed of two subphyla, $\gamma-Proteobacteria$ and Low G+C gram-positive bacteria in both areas, and in August a-Proteobacteria was added to the community just in the natural forest area. The direct influence of acidic deposition on the acid-tolerant bacterial phylogenetic composition could not be detected in higher taxonomic levels such as subphylum, but at narrower or finer levels it could be observed by a detection of Xanthomonadales group of $\gamma-Proteobacteria$ just in the industrial estate.

• Architectural research
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• v.21 no.1
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• pp.21-29
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• 2019

Recent years in Korea, some new developed buildings are only using electricity as power for heating, cooling, bathing and even cooking which means except electricity, there is no natural gas or other kinds of energy used in such kind of building. In vehicle industry area, scientists already invented electric vehicle as an environment friendly vehicle; after that, in architecture design and construction field, buildings only using electricity appeared; the curiosity of the environment impact of energy consumption by such kind of building lead me to do this research. In general, electricity is known as a clean energy resource reasoned by it is noncombustible energy resource; however, although there is no environmental pollution by using electricity, electricity generation procedure in power plant may cause huge amount of environment pollution; especially, electricity generation from combusting coal in power plant could emit enormous air pollutants to the air. In this research, the yearly amount of air pollution by energy using under traditional way in research target building that is using natural gas for heating, bathing and cooking and electricity for lighting, equipment and cooling is compared with yearly amount of air pollution by only using electricity as power in the building; result shows that building that only uses electricity emits much more air pollutants than uses electricity and natural gas together in the building. According to the amount of air pollutants comparison result between two different energy application types in the building, residential SOFC (Solid oxide fuel cell) is simulated to apply in this building for decreasing environment pollution of the building; furthermore, high load factor could lead high efficiency of SOFC, in the scenario of simulating applying SOFC in the building, SOFC is shared by two or three households in spring and autumn to increase efficiency of the SOFC. In sum, this research is trying to demonstrate electricity is a conditioned environment friendly energy resource; in the meanwhile, SOFC is simulated efficiently applying in the building only using electricity as power to decrease the large amount of air pollutants by energy using in the building. Energy consumption of the building is analyzed by calibrated commercial software Design Builder; the calibrated mathematical model of SOFC is referred from other researcher's study.

• Clean Technology
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• v.28 no.2
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• pp.174-181
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• 2022

Biomass is a sustainable alternative resource for production of liquid fuels and organic compounds that are currently produced from fossil fuels including petroleum, natural gas, and coal. Because the use of fossil fuels can increase the production of greenhouse gases, the use of carbon-neutral biomass can contribute to the reduction of global warming. Although biological and chemical processes have been proposed to produce petroleum-replacing chemicals and fuels from biomass feedstocks, it is difficult to replace completely fossil fuels because of the high oxygen content of biomass. Production of petroleum-like fuels and chemicals from biomass requires the removal of oxygen atoms or conversion of the oxygen functionalities present in biomass derivatives, which can be achieved by catalytic hydrodeoxygenation. Hydrodeoxygenation has been used to convert raw biomass-derived materials, such as biomass pyrolysis oils and lignocellulose-derived chemicals and lipids, into deoxygenated fuels and chemicals. Multifunctional catalysts composed of noble metals and transition metals supported on high surface area metal oxides and carbons, usually selected as supports of heterogeneous catalysts, have been used as efficient hydrodeoxygenation catalysts. In this review, the catalysts proposed in the literature are surveyed and hydrodeoxygenation reaction systems using these catalysts are discussed. Based on the hydrodeoxygenation methods reported in the literature, an insight for feasible hydrodeoxygenation process development is also presented.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.291-301
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• 2023

The purpose of this study is to examine the perception of early childhood teachers on ecological art activities oriented to education for sustainable development. The research results are as follows. First, Early childhood teachers recognized the visual art of natural media, the pursuit of community values, and the participation and communication of social members as educational significance of ecological art activities. And difficulties in practicing ecological art were recognized as lack of educational environment, lack of ecological art teaching materials and specific examples, and teachers' lack of understanding of ecological art. Also, they recognized that ecological art activities foster core competencies in art experience area, such as nature-friendly communication skills, eco-friendly sensibility, and creative convergence skills. Second, regarding ecological art activities and sustainable development education, early childhood teachers considered the difficulties in practice as lack of awareness about sustainable development, lack of play meia and materials, lack of educational policies and support, and insufficient teacher training programs. Also, regarding the SDGs that can be practiced in ecological art activities, teachers were found to be highly aware of 'grow affordable and clean energy', 'improve clean water and sanitation', 'provide quality education' in the order. In the contents of education for sustainable development that can be practiced in ecological art activities, teachers are given the order of 'climate change response', 'clean energy', 'water and sanitation', 'quality education', 'health and well-being' and 'marine ecosystem'. was highly recognized. If an ecological art activity program is developed, the rate of responding that it will be used is high, so it is considered that the development of an ESD-oriented ecological art activity program is urgent.