• Economic and Environmental Geology
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• v.52 no.5
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• pp.347-356
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• 2019

Various studies regarding the sedimentary environment, depositional age, provenance, and metamorphic history have been carried out on the Taean Formation in the western part of Gyeonggi Massif, since the unique detrital zircon age pattern was revealed. This review paper introduces the previous researches on the Taean Formation and discusses the depositional age and provenance. The Taean Formation was traditionally regarded as a Precambrian stratigraphic unit, but recently it is interpreted to be a middle or upper Paleozoic formation due to the occurrence of large amounts of Early to Middle Paleozoic detrital zircons. The Taean Formation consists of metasandstone, argillaceous schist, and phyllite which are mainly made up of quartz and mica. The protoliths are interpreted as turbidites deposited in deep sea fan environment. The Taean Formation has been interpreted to be deposited between the Devonian to Triassic ages given the age differences between detrital zircons and intrusive rocks. There are two opinions that the deposition age is close to the Devonian or the Permian period. The provenance of this formation is supposed to be South China block, Chinese collisional belt, or Gyeonggi Massif. Given the available detrital zircon ages of the Taean Formation and other Korean (meta)sedimentary rocks, the Taean Formation shares major source rocks with Yeoncheon Group and Pibanryeong Unit of the Okcheon Supergroup, but their source regions are not entirely consistent. Considering the existing hypotheses about the depositional timing and provenance, we put weight on the possibility that the Taean Formation was deposited between Permian and Early Triassic periods. However, further studies on the stratigraphy and sedimentary petrology are needed to clarify its definition and to elucidate the provenance.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.5
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• pp.107-114
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• 2019

In many military aircraft, s-shaped diffusers are used to prevent the fan blades of the turbofan engine from being exposed to the outside. The inlet configurations of the air intakes for military aircraft vary, such as the rectangular intake of the F-22, the crescent-like intake of the F-16, elliptical intake of the MQ-25. In this study, the aerodynamic performance of s-shaped diffusers with various inlet configurations was evaluated using numerical analysis. In addition, the configuration of the middle section of an s-shape duct was changed to the crescent shape, and the effects on its aerodynamic performance were investigated. As a result, there was a slight difference in total pressure recovery according to various inlet configurations with ellipse-shaped middle sections. Also, the total pressure distortion was the lowest in the rectangular inlet shape. When the configuration of the middle section was changed from an ellipse to a crescent shape, the total pressure recovery remained at a high level, except for the ellipse-shaped inlet configuration. In terms of total pressure distortion, the duct with the crescent-shaped middle section showed a significantly more uniform pressure distribution than that with the ellipse-shaped middle section.

• Elastomers and Composites
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• v.40 no.4
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• pp.266-271
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• 2005

In this work, the thermal stability factors, such as the thermal decomposition temperature, decomposition activation energy ($E_d$), and char yield, were measured to investigate the effect of silicone rubber (SR) content on the thermal stabilities of EPDM/SR blends. As a result, the thermal decomposition curve of EPDM/SR blends was similar to the neat EPDM rubber at 10 wt% SR and the thermal decomposition temperature increased above this content. The $E_d$ value of EPDM rubber initially decreased and then was constant above 20 wt% weight losses. The $E_d$ of EPDM/SR blends was higher than that of the neat EPDM rubber and then decreased with increasing the weight loss when the SR content was in the range of 10-20 wt%. Whereas the $E_d$ of the blends was lower than that of the EPDM rubber and then decreased with increasing the weight loss when 30 wt% SR was added. The char yield at $800^{\circ}C$ increased with increasing the SR content, because the decomposition of silane groups in the backbone was capable of forming a silane-rich residue after the initial stage of thermal degradation, which finally prevents further heat transfer and diffusion in the blends.

• Food Science and Preservation
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• v.24 no.3
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• pp.374-380
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• 2017

The quality characteristics of 'Xiangshui' pears (Pyrus ussuriensis) treated with different concentrations of biomass pyrolysis liquid (BPL) during storage at $25^{\circ}C$ were investigated. The weight of 'Xiangshui' pears treated with BPL declined at a slower rate than that of the control. The rot index of BPL-treated 'Xiangshui' pears decreased with increasing storage times, and treatment with 20-fold-diluted BPL resulted in the lowest rot index after storage for 12 days. The total acid content of 'Xiangshui' pears treated with 20-fold-diluted BPL was 0.19%, and was the highest after storage for 12 days. After storage for 12 days, the total sugar content of 'Xiangshui' pears treated with 20-fold-diluted BPL was 7.19%; this was significantly higher than that of the control, but not significantly different from that of pears treated with other BPL dilutions. The vitamin C content of 'Xiangshui' pears showed a decreased trend, and pears treated with 20-fold-diluted BPL had a vitamin C content of 2.21 mg/100 g after storage for 12 days and showed the least decline compared to other treatments. In addition, respiration in 'Xiangshui' pears was effectively inhibited by treatment with BPL. In conclusion, BPL treatment exerts a protective effect on the quality of 'Xiangshui' pears during storage, with 20-fold-diluted BPL being the most effective.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.595-603
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• 2021

Sand layer distribution, which is the main target of river and land aggregate resources, mainly belongs to alluvial and river sedimentary environments among the Quaternary sedimentary environments. The distribution of aggregate resources in the area of Geumsan-gun, Chungcheongnam-do is characteristically developed around a sedimentation environment in which intrusive meandering river dominate. Although the area around Bonhwangcheon Stream and the area near the confluence of small streams are small, the river floodplain develops and corresponds to the aggregate distribution area. The sedimentary layer formed in the sedimentary environment such as colluvial deposits or alluvial fan deposits has a relatively low distribution rate of aggregate resources. The vertical distribution of the Quaternary sedimentary layers in the Geumsan-gun region ranges from about 5 to 12 m and has an average Quaternary sedimentary thickness of 8 m. The aggregate-bearing section has an average thickness of 3.6 m, and the average grain size is about 21% clay-silt, 67% sand, and 12% gravel. The main characteristics of the aggregate-bearing section are that coarse-grained sand predominates, and gravel is sub-angular or sub-rounded, and the sorting is generally poor and has a massive form of deposits, and the soil colour ranges from dark grey to yellowish-brown. In Geumsan-gun, the most likely distribution area for aggregate development is the alluvial sedimentary and river sedimentary layers distributed along the current and former riverbeds of the main Geumgang River, Bonhwangcheon and small River tributaries.

• Journal of Conservation Science
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• v.37 no.5
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• pp.505-515
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• 2021

In this study, we evaluated the slope stability of the Pohang Daljeon-ri columnar joint (Natural Monuments # 415) and calculated the maximum energy, jumping height and moving distance of rockfalls using a simulation. Based on the results, we established the range of rockfall risk. The slopes of the Pohang Daljeon-ri columnar joint have dip directions of 93.79°, 131.99°, 165.54° and 259.84° from left (SW) to right (NE). Furthermore, they have a fan-like shape. The Pohang Daljeon-ri columnar joints are divided into four sections depending on the dip direction. The measurement results of the discontinuous face show that zone 1 is 125, zone 2 is 261, zone 3 is 262, zone 4 is 43. The results of slope stability analyses for each section using a stereographic projection method correspond to the range of planar and toppling failure. Although it is difficult to diagnose the type of failure, risk evaluation of currently falling rocks requires further focus. The maximum movement distance of a rockfall in the simulation was approximately 66 m and the rockfall risk range was the entire area under slope. In addition, it is difficult to forecast where a rock will fall as it rolls in various directions due to topographic factors. Thus, the installation of measures to prevent falling is suggested to secure the stability based on the results of the rockfall simulations and its probabilistic analysis.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.9
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• pp.721-736
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• 2019

In this paper, the behavior of the fire smoke due to the operation of the ventilation systems when the fire occurred in the underground station (6 basement floors) and the tunnel at the great depth was measured. Fire smoke was generated by using a smoke generator which realized heat buoyancy effect by using hot air blower. The two locations of the fire were selected on the platform and on the platform of the tunnel located outside the screen door. A ventilation mode is generally used in which smoke is exhausted through a vent hole provided in a platform when a platform fire occurs. The tests were performed by operating the exhaust through the ventilation holes of the tunnel part located at both ends of the platform. The smoke density and the wind speed/velocity were measured at various positions, and the videos were taken to analyze the movement and smoke of the smoke. In both cases for fire inside the platform and in the railway tunnel, due to the ventilation mode operation of the fan for the platform and the exhaust of the fans in the tunnel smoke were well exhausted and the smoke propagation to the area near the smoke zone was suppressed. The smoke-control mode, which is applied to both fans for the platform and fans for in the tunnel at both ends of the platform, can provide a safer evacuation environment to the passengers from the fire smoke when the platform fire or fire train stops.

• Cross-Cultural Studies
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• v.40
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• pp.213-238
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• 2015

This article attempts to correct errors in five words related to Shiji (The Grand Scribe's Records) Liezhuan (A Series of Biographies), which are presented in the Great Chinese-Korean Dictionary. The author analyses the problems with meaning interpretations of three words and additional meaning interpretations of two words. The main points of the study are presented in the following. First, in relation to the error correction in meaning interpretation, this study finds out that the explanations of "jiayu," "jiaochi," and "guancai" in the Great Chinese-Korean Dictionary are incorrect. Most of the cases include plausible interpretations of the words that are likely to cause readers to be confused with the meanings. Each of the words should be interpreted as "lend${\rightarrow}$give," "arrangement${\rightarrow}$new decoration, ornamentation, or embellishment after removing old one," and "accept something carefully or accept something after inspection${\rightarrow}$look over carefully or search for something." Second, as for the supplementary correction, this study points out that the explanations of "xiaoshi" and "shennian" are not sufficient. The following meanings for each word should be added, including "display skills" and " be trapped inside one's own mind." Furthermore, when comparing with the different translation versions by scholars at home and abroad, we can come to a following conclusion. The interpretations made by Zheng, Fan-Zhen are the most accurate for the "jiayu" item. With respect to the "jiaochi" item, the interpretations given by Piao, Yi- Feng; Wang, Li-Qi; Yang, Zhong-Xian; and Hao, Zhi-Da are relatively appropriate. The "guancai" item is adequately interpreted by Piao, Yi-Feng and Wang, Li-Qi. In the meaning interpretation of the "xiaoshi," Jin, Yuan- Zhong gave correct explanations. In addition, it is considered that Wang, Zhong provided the most ideal translations for the item "shennian."

• The Korean Journal of Archival Studies
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• no.55
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• pp.73-96
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• 2018

Andy Warhol's "Time Capsule" is an individual's daily record, but it can also be evaluated as an artwork. Andy Warhol kept most of his items in boxes until his death in 1974. Warhol's personal records contained receipts, invitations, memos, letters, voice tapes, newspapers, magazines, fan letters, mails, and exhibit materials. Andy Warhol's act of collecting items was continuous and repetitive, giving others a deeper insight into the artist's life. Warhol constantly recorded daily repetitive behaviors such as the people he met, a list of books he bought, and movies he had watched as a record producer. In addition, occasionally, he was in the position of an archivist, collecting and organizing others' records. As such, he expressed his passion for recording his surroundings. His intentionally produced or collected records contain valuable information, not only of himself but also of the people surrounding him. His personal records show that it is the material that enables people to understand and appreciate his relationship with contemporary artists, as well as the artist's education and the conditions during his time.

• Journal of the Korean Institute of Gas
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• v.23 no.3
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• pp.1-6
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• 2019

The purpose of the present study is to elucidate flue gas recirculation device for reduction of nitrogen oxides using coanda nozzle without adopting additional power driving fan in a waste incinerator. The characteristics of the exhaust gas recirculation flow rate and the average temperature change at the outlet of the mixed gas were investigated according to the change of air supply nozzle gap and the position of air supply nozzle. When the gap of the air supply nozzle was changed to 3.22, 4.03, and 4.84 mm, the largest recirculation flow ratio, which is the ratio of exhaust gas recirculation flow rate and air supply flow rate, was 2.227 for the case with 3.22 mm and its mean temperature at outlet was $594.8^{\circ}C$. When the position of the air supply nozzle changes to the front position, neck position, and expansion position of the coanda nozzle neck, the recirculation flow ratios at the forward position and the neck position were nearly almost the same value, 1.843, and 1.696 at the expansion position, their mean temperatures were $559.8^{\circ}C$ and $544.3^{\circ}C$, respectively.