• Journal of Aerospace System Engineering
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• v.17 no.1
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• pp.51-58
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• 2023

Hypergolic propellants, which can ignite themselves without an ignition source, are difficult to handle due to their corrosiveness and toxicity. Therefore, it is necessary to develop green hypergolic propellants with little or no toxicity. In this study, basic research on green hypergolic ignition propellants was conducted. With 95% hydrogen peroxide as an oxidizer and CNU_HGFv1 as a fuel, ignition and combustion characteristics of propellants were evaluated through a drop test, an ignition test, and a combustion test. As a result of the drop test, the ignition delay time was 9.7 ms. It was 27 ms in the ignition test, which was fast enough to be used as a propellant. As a result of the combustion test, a combustion efficiency of 95.4~98.1% was achieved at about 11.7 bar. It was confirmed that fast and stable combustion was possible without hard start or combustion instability.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.155-163
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• 2014

BACKGROUND: Recent studies for heavy metal stabilization in soil were mainly focused on finding out new materials and its efficiency. But, such a stabilization method can cause disturbance to soil, leading improper environment for agriculture. The object of this study was to demonstrate the effect of the incorporation of green manure crops on heavy metal-contaminated soil. METHODS AND RESULTS: Soil contaminated with heavy metals was collected from the agricultural soils affected by the abandoned mine. Lime stone was selected and treated to contaminated soil. Three kinds of legume green manure crops; Alfalfa (Medicago sativa), Hairy vetch (Vicia villosa), Red clover (Trifolium pratense) were subsequently cultivated in greenhouse condition. It was found that lime stone increased soil pH and decreased the amount of heavy metal absorption by green manure. The application of green manure residues on soil increased soil pH and inorganic nitrogen. CONCLUSION: The C/N ratio of three green manures was low, indicating fast decomposition rate, resulting in nitrogen supplement, consequently. Considering the point that the soil was used for agricultural purpose, it was recommended that hairy vetch and red clover were preferred. Nevertheless, the heavy metal availability was also increased. Thus, it seemed that further study was needed to confirm that how long maintain a phenomenon.

• Korean Journal of Community Nutrition
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• v.13 no.6
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• pp.829-839
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• 2008

The purpose of this study was to investigate the relation of the fast food and beverage intake on sociality and anger expression of adolescents. Questionnaires were distributed to the adolescents of 599 middle and high school students in Busan. According to the results, the preference-intake frequency analysis (PEA) on fast food grid, high preference and high intake frequency were 'dukbokki', 'chicken' and 'mandu' and low preference and high intake frequency were 'ramyon', 'gimbab. PEA on beverage grid, high preference and high intake frequency were 'milk-dairy product', 'fruit juice', 'isotonic beverage' and low preference and high intake frequency were 'carbonate drink'. The intake frequency of 'pizza', 'sandwich', 'udong', and 'dukbokki' had a positive relationship with sociality. 'Hamburger', 'chicken', 'french fry', 'gimbab', 'mandu', and 'ramyon' showed a positive relationship with anger-out. The intake frequency of 'carbonated drink' had a negative relationship with anger-control, but 'green tea' showed a positive relation with it. 'Carbonate drink', 'isotonic beverage', 'coffee', and 'milkshake' had a negative relationship with anger-out. The explanation power ($R^2$) of intake of fast food and beverage on sociality was $0.019{\sim}0.038$, and 'carbonated drink' and 'coffee' had a negative influence on sociality. The explanation power ($R^2$) of intake of fast food and beverage on anger expression was $0.011{\sim}0.041$, and 'carbonated drink' had a negative influence on angercontrol. 'Hamburger', 'carbonated drink', and 'coffee' showed a positive influence on anger-out. From these results, it was necessary to develop the practical eating-out habits program on proper fast food and beverage choice for adolescents.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.3
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• pp.178-183
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• 2014

Recently, various type of nanomaterials such as nanorod, nanowire, nanotube and their core/shell nanostructures have attracted much attention in photocatalyst due to their unique properties. Among them, Type-II core/shell heterostructures have extensively studied because it has exhibited improved electrical and optical properties against their single-component nanostructure. Such structures are expected to offer high absorption efficiency and fast charge transport due to their stepwised energetic combination and large internal surface area. Thus, it has been considered as potential candidates for high efficient photocatalytic activity. In this work, we introduce a novel chemical conversion process to synthesize Type-II ZnO/ZnSe core/shell heterostructures. A plausible conversion mechanism to ZnO/ZnSe core/shell heterostructres was proposed based on SEM, XRD, TEM and XPS analysis. The ZnO/ZnSe heterostructures exhibited excellent photocatalytic activity toward the decomposition of RhB dye compared to the ZnO nanorod arrays due to enhanced light absorption and the type-II cascade band structure.

• International Journal of Costume and Fashion
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• v.10 no.2
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• pp.61-71
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• 2010

The purpose of this study was first, to examine the causes for the recent acceleration in the increase of textile/apparel waste and the current practices for reducing waste in the global textile and apparel industry; and second, to explore the influence of sustainability and social responsibility on fashion trends. Extensive literature on sustainable apparel and sustainable and socially responsible practices by global textile and apparel firms was reviewed in conducting this research. First, an accelerated fashion diffosion speed due to fast fashion was focused on as a cause for the increase in textile/apparel waste whereas mass customization was focused on as a potential solution for reducing waste. Then, the influence of the social trend toward sustainability and social responsibility on fashion trends was discussed, particularly the trends toward green products and recycled fashion, the trend against using real for or leather, and minimum-fabric-waste fashion in design and product development. This study furthers consumers' understanding of sustainability and social responsibility related to fashion trends and hopefully increases their consciousness in becoming socially responsible consumers. This study will also contribute to better decision-making in apparel and textile firms to produce sustainable fashion products.

• Carbon letters
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• v.10 no.2
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• pp.123-130
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• 2009

Multi-elements doped $TiO_2$ was prepared as a new photocatalyst in order to decrease the band gap of $TiO_2$ by sol-gel process which can provide the large active sites of $TiO_2$. Multi-elements were doped by using a single precursor, tetraethylammonium tetrafluoroborate (TEATFB). By the benefit of large specific surface area of $TiO_2$ prepared by sol-gel process, catalysts showed initial fast removal of dye. The photoactivity showed that the doped catalysts significantly promote the light reactivity than undoped $TiO_2$. The commendable photoactivity of prepared catalysts is predominantly attributable to the doping of anions which may reduce the band gap.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.7
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• pp.486-489
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• 2018

Solution-processed organic light-emitting diodes (OLEDs) have the advantages of low cost, fast fabrication, and large-area devices. However, most studies on solution-processed OLEDs have mainly focused on solution-processable hole transporting materials or emissive materials. Here, we report fully solution-processed green OLEDs including hole/electron transport layers and emissive layers. The electrical and optical properties of OLEDs based on solution-processed TPBi (2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)) as the electron transport layer were investigated with respect to the spin speed and the number of layers. The performance of OLEDs with solution-processed TPBi exhibits a power efficiency of 9.4 lm/W. We believe that the solution-processed electron transport layers can contribute to the development of efficient fully solution-processed multilayered OLEDs.

• Korean Journal of Optics and Photonics
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• v.8 no.3
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• pp.199-203
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• 1997

Fine displacement of spherical suface was detected and analyzed by Twyman-Green interferometer and the interferogram analysis using Fourier transform method. The surface profile was obtained from single interferogram by introducing the carrier freguency to the interferogram. The interferogram was processed in the spatial frequency domain by fast Fourier transform, and the phase distribution was obtained by inverse Fourier transform. The 3-dimensional distribution for the surface displacement was obtained. It was compared with the calculated surface displacement and the error was less than λ/10.

• Journal of Mushroom
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• v.12 no.2
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• pp.132-137
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• 2014

Green mold disease caused by Trichoderma species has recently caused considerable damage to oyster mushroom industries in Korea. This disease Trichoderma, Penicillium, Aspergillus, such as in (genus) to be included in a disease caused by a species that collectively the largest incidence and damage is caused by the pathogen Trichoderma genus. T. longibrachiatum, Trichoderma koningii, Trichoderma virens, T. hazianum, T. atroviride, and T. pseudokoningii were detected on oyster mushroom beds and, of them, T. virens, T. hazianum, T. longibrachiatum was the most frequently detected. The knowledge concerning physiological and ecological properties of Trichoderma spp. was essential for their effective control. T. longibrachiatum hyphal growth is very fast, spore formation, and, particularly well-chlamydospore formation characteristics, and reviews are dark green discoloration. T. koningii, fast mycelial growth, aerial hyphae and spores in aerial hyphae formation is concentrated. T. virens, especially if the color change caused by spore-forming, slow, late in infection, the more severe the damage is discovered. T. hazianum fast mycelial growth, white aerial hyphae and late turns dark green. After spore formation hyphae glob of white pustules or tufts on the top of the formation. T. atroviride. aerial hyphae usually the mycelial growth and spore formation in the unlikely event of the formation and smells similar to the smell of coconut is that. Fast T. pseudokoningii mycelial growth, spore formation is formed around the inoculation site, discoloration of the medium color and well formed chlamydospores.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.2
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• pp.425-431
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• 2007

The purpose of this study was to observe the effects of Achyranthes Radix(AR) and electroacupuncture(EA) in rats with rheumatoid arthritis induced by type II collagen for 28 days. Control group was daily administered 0.9% NaCl 0.5 $m{\ell}$, Group I was daily administered 0.9% NaCl 0.5 $m{\ell}$ to arthritic rats, Group II was orally administered with Achyranthes Radix 500 mg/kg 0.5 $m{\ell}$ to arthritic rats. Group III was given 2 Hz EA of chok samni acupoint(ST36) in the test group for 30 min/days to arthritic rats. Group IV was daily orally administered with Achyranthes Radix 500 mg/kg 0.5 $m{\ell}$ and 2 Hz EA of chok samni acupoint(ST36) in the test group for 30 min/days to arthritic rats. This studies have been designed to evaluate the hind paw edema, assessment of arthritis indices, analgetic effects by analysis of blood chemistry(WBC, CRP, ALP, AST). In each group, histologic observations, Safranin O-fast green stain were observed and analyzed. The following results were obtained. Group II, III, IV were significantly decreased arthritis indices and the rate of paw edema compared with Group I . Especially group IV was the most significantly decreased. The WBC, CRP, AST, ALT was that Group II, III, IV were significantly decreased compared with Group I . In conclusion, Achyranthes Radix and Ea contribute to the improvement of blood chemistry and change in safranin O-fast green by knee joint of arthritic rats.