• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.39-47
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• 2015

In this study, the properties of strength and drying shrinkage of alkali-activated slag cement (AASC) with magnesium oxide (MgO) contents between 0 and 16 wt% were investigated. The ground granulated furnace blast slag (GGBFS) was activated by potassium hydroxide (KOH) and dosage of activator was 2M and 4M. The MgO was replaced with 2% to 16% of GGBFS by weight. The water-binder ratio (w/b) was 0.5. In the result, the higher MgO content leads to a slightly higher degree of reaction and thus to a higher compressive strength at all ages. The compressive strength and ultra sonic velocity (UPV) increased with increases MgO contents. The drying shrinkage of AASC was decreased as the contents of MgO increases. The results from SEM confirmed that there were densified reaction product of higher MgO content specimens.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.302-309
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• 2019

This paper shows an experimental study for fundamental characteristics of alkali activated fly ash-slag cement paste exposed to seawater of 5℃. Fly ash and slag were blended in three different ratios; 6:4, 7:3, and 8:2. Activators (NaOH and Na2SiO3) used 5% of the binder weight. It was shown that as the fly ash substitution rate in creased, compressive strength and density decreased, and water absorption rate increased. The results of X-ray diffraction and thermogravimetry showed that hydration reactants formed in samples did not differ significantly, however, C-S-H gel increased as the slag substitution rate increased. It showed that mechanical properties of fly ash-slag cement pastes under 5℃ seawater condition were affected by the slag substitution rate rather than fly ash.

• The Journal of the Korea Contents Association
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• v.22 no.4
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• pp.468-478
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• 2022

'True education', which was the core ideology of 'the Korean Teachers & Educational Workers Union', is re-appropriated in the new media era. This word, which is actively used by young people, means 'punishment against the object of social condemnation'. One of the characteristics of 'true education contents' commonly seen on the Internet is that it shows a tendency to 'fragmentation'. True educational contents are short in length, and the contents are very local. This reflects the characteristics of a postmodern society where totality disappears and small stories are consumed. Second, the standard for dividing good and evil is extremely 'arbitrary'. Whereas the existing stories of rewarding virtue and punishing vice had universal values such as love, consideration, and peace, the content of true education distinguishes good and evil with an extremely narrow perspective. The way to justify arbitrary standard is to incite public outrage. Third, 'humour' is added. Here, humor is combined with the emotion of hatred, causing the problem of weakening people's critical consciousness.

• Korean Journal of Environmental Agriculture
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• v.41 no.4
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• pp.223-229
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• 2022

BACKGROUND: Mining activities, smelter discharges, and sludges are the major sources of heavy metal contamination to soils. The objective of this study was to determine the efficiency of magnetite and bottom ash derived from coal ash in remediating As-contaminated soil. METHODS AND RESULTS: An incubation experiment was conducted for 10 weeks. Magnetite and bottom ash at different rates and ratios were applied to each plastic bottle repacked with 1,000 g of dried As-contaminated soil. After 3-weeks of incubation, the concentrations of available As were measured by using Mehlich-3, SBET, and sequential extraction methods. All of the subjected soil amendments resulted in significant decreases in available As concentration compared to the controls. The addition of magnetite at the highest rate was the best to stabilize As in the soils; however, the values of As concentration varied with the extraction methods. CONCLUSION(S): To ensure the stabilization accuracy of heavy metals in soil, both single and sequential extractions are recommended. The magnetite derived from fly coal ash can also be applicable as a heavy metal stabilizer for the As-contaminated soil.

• Cross-Cultural Studies
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• v.47
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• pp.291-312
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• 2017

This paper examines how 'house' is meaningful in Chi Li's novel. Chi Li focuses on the house as a symbol of status, and the house as a place of gender performance. First, as a sign that symbolizes an individual's identity, 'house' is divided into intellectual and petit bourgeois, and constitutes binarism into civilization/non-civilization, knowledge/non-knowledge, spirit/anti-spirit and superior/inferior. In recognizing the irrationality and unfairness behind house symbolizing intellectual and petit bourgeois, Chi Li shatters the boundaries of the binaralized house as a sign of identity. Second, it dismantles the house as a place where gender is (re)produced. This is accomplished through two aspects. One is to re-define a private area house as a public area in which economic activity occurs. The house, as a public area in which economic activity occurs, becomes a place where women are reborn as economic entities. Passive, dependent femininity is reconstructed as independent and subjective. The other dismantles the definition of the house which is identified with masculinity. The house identified with masculinity is a place that symbolizes the socio-economic capacity of men. According to the socio-economic ability of males, the house is a place symbolizing the realization of masculinity, and it becomes a place to fix the gender order while reproducing masculinity. It may become a place to experience the weakening or defamation of masculinity. At that moment, the house becomes a place where the gender order of masculinity and femininity is overturned. Through this, Chi Li reconstructed, and in a sense revolutionized the definition of the house as a place where traditional gender is (re) produced by dismantling the definition of fixed femininity or masculinity.

• Economic and Environmental Geology
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• v.55 no.6
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• pp.583-596
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• 2022

The rock surface of Bangudae petroglyphs is mainly dark brown hornfelsified shales by contact metamorphism. The surface form a weathered layer of a invariable depth, and there is a difference with mineral and chemical composition between weathered and non-weathered layers. Surface of the petroglyphs has been discolored to light brown over the face due to biological and chemical weathering. As the measuring chromaticity based on the non-weathered layer, the whiteness and yellowness increased in the weathered layer, and the color difference (ΔE) was 5.54 to 36.89 (mean 17.26). In the weathered layer of the petroglyph surface, the CaO content was reduced by about 90% compared to the non-weathered layer, and Sr also showed the same trend. In particular, the mean porosity of the non-weathered layer was 0.4%, but it was estimated as 25.0% in the weathered layer. This is interpreted as the fact that calcite reacts with water, and forms a weathered layer from the surface as it is eluted. Based on the weathering depth modeling of the petroglyphs using the penetration characteristics of X-rays, the weathering depth of rock faces was found to be 1 to 2mm. However, the area classified as 2mm or more estimated to be a maximum of 3 to 4mm, considering the weathering depth around the petroglyphs surface.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.629-646
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• 2023

Host rock of Cheonjeon-ri petroglyph is shale belonging to the Daegu Formation of Cretaceous Gyeongsang Supergroup. The rocks were hornfelsified by thermal alteration, and shows high density and hardness. The petroglyph forms weathered zone with certain depth, and has difference in mineral and chemical composition from the unweathered zone. As the physical deterioration evaluations, most of cracks on the surface appear parallel to the bedding, and are concentrated in the upper part with relatively low density. Breakout parts are occurred in the upper and lower parts of the petroglyph, accounting for 6.0% of the total area and occurs to have been created by the wedging action of cracks crossing. The first exfoliation parts occupying the surface were 23.8% of the total area, the second exfoliations covered with 9.3%, and the exfoliation parts with three or more times were calculated as 3.4%. It is interpreted that this is not due to natural weathering, and the thermal shock caused by the cremation custom here in the past. As the ultrasonic properties, the petroglyph indicates highly strength in the horizontal direction parallel to bedding, and the area with little physical damage recorded mean of 4,684 m/s, but the area with severe cracks and exfoliations showed difference from 2,597 to 3,382 m/s on average. Physical deterioration to the Cheonjeon-ri petroglyph occurred to influence by repeated weathering, which caused the rock surface to become more severe than the inside and the binding force of minerals to weaken. Therefore, it can be understood that when greater stress occurs in the weathered zone than in the unweathered zone, the relatively weathered surface loses its support and exfoliation occurs.

• Korean Journal of Organic Agriculture
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• v.32 no.1
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• pp.75-90
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• 2024

Biochar is a solid substance with a high carbon content, as it is made out of biomass pyrolyzed under the condition of limited oxygen. This product has attracted attention as an environment-friendly soil amendment because it contributes to carbon neutrally and has improvement effects on the soil environment. This study conducted an experiment to evaluate soil physiochemical properties and microbial community changes in a melon greenhouse according to the applied amount of biochar to investigate the growth characteristics and yields of melons accordingly. In soil physical properties, an increase in the applied amount of biochar resulted in a decrease in bulk density and an increase in porosity of the soil, improving air permeability. In soil chemical properties, an increase in the applied amount of biochar led to a increasing of pH, organic matter and available phosphate content. In the growth characteristics of melons, there was a growing tendency of plant height, leaf length and leaf width according to the increasing application of biochar until 10,000 kg/ha. Moreover, melon yields also increased as the amount of biochar, 13~16% higher in 10,000 kg/ha biochar application than no treatment. Compared differences among microbial communities in the soil according to the application of biochar and found that plant beneficial bacteria dominated in biochar treatments. This study demonstrated the potential of biochar as an effective soil amendment in melon greenhouse by showing improvements in soil physicochemical properties and microbial communities.

• Cartoon and Animation Studies
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• s.33
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• pp.317-341
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• 2013

Found Footage Film has been increasingly addressed between film and visual art world in the age of rapid media change. With regards to this self-conscious found footage filmmaking, narrative structures are unraveled to relate new stories, images are removed from their original context only to reappear in a different context, new layers that alter the meaning are added, stereotypes from Hollywood movies are exposed, and new montages are used to destroy the illusion of the medium itself. The physical properties of the original material are also emphasized or altered in order to add a new meaning. The starting point of this study is the recognition of the origin of found footage film. It traces back to the found object from primitive impulse and found art from Dada and surrealism. Many found footage films have been at least partly inspired by Duchamp's ready-mades. These films use footages that the filmmakers did not shot, and even footage that was never intended as art. This essay deals with the found footage practices and interrogates the aesthetic implications by the concept of self-reflexivity. Self-reflexivity means consciousness turning back on itself, and found footage film is about films which call attention to themselves as cinematic constructs. It breaks with art as illusionism and exposes their own factitiousness as textual constructs. Furthermore, the inevitable mortality of celluloid and temporal reconstruction of original film will be treated. Recentely, many attention has been given to role of Found Footage Film. I hope to add the understanding of the artistic found footage film with this study.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.26-32
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• 2012

This study has been performed Thermal Shock test for analyze the cause of Power drop in PV(Photovoltaic) Module. Thermal Shock test condition was performed with temperature range from $-40^{\circ}C{\sim}85^{\circ}C$. One cycle time is 30min. which are consist of low and high temperature 15min. each other. The test was performed with total 500cycles. EL, I-V were conducted every 100cycle up to 500cycles. Mono Cell resulted in 8% Power drop rates in Bare Cell and 9% in Solar Cell. In the case of Multi Cell resulted in 6% Power drop rates in Bare Cell and 13% in Solar Cell. After Thermal Shock test, Solar Cell's Power drop resulted from surface damages, but in the case of Bare Cell's Power drop had no surface damages. Therefore, Bare Cell's Power drop was confirmed as according to leakage current increase by analysis of Fill Factor after Thermal Shock test. Also, Solar Cell's Power drop rates are higher than that of Bare Cell because of surface damages and consuming electric power increase. From now on, it should be considered that analyzed the reasons of Fill Factor decrease and irregular Power drop in PV module and Cell level using cross section, various conditions and test methods.