• Journal of the Korean Society of Earth Science Education
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• v.16 no.1
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• pp.72-86
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• 2023

The purpose of this study is to examine what epistemological beliefs pre-service teachers have about science depending on the situation, and to explore in-depth changes in epistemological beliefs through disciplinary reading. For this purpose, 77 essays written by pre-service elementary school teachers after reading Feynman's 'the meaning of it all' were analyzed using an inductive analysis method. As a result of the study, the epistemological beliefs of pre-service teachers were divided into two situations: 'science in subject learning' and 'science in daily life', and the epistemological beliefs formed in the 'science handled by scientists' situation were analyzed after reading the book. Each situation was divided into sub-categories of 'Impression of Knowledge', 'Source of Knowledge', 'Justification of Knowledge', 'Variability of Knowledge', 'Structure of Knowledge', and 'Value of Knowledge Acquisition' to reveal differences in sophisticated beliefs and naive belief levels. As a result, it was derived that Feynman's science lecture influenced pre-service teachers in terms of establishing new perspectives and recontextualizing existing epistemological beliefs. This study is meaningful in that pre-service teachers' scientific epistemological beliefs may vary depending on the situation, and that the scope and depth of epistemological beliefs may be expanded to include scientists' beliefs in science through disciplinary reading.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.127-142
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• 2024

This study aimed to understand the interrelationships between tree species in plant communities through Plant Social Network (PSN) analysis using a large amount of vegetation data surveyed in an island area belonging to a warm-temperate boreal forest. The Machilus thunbergii, Castanopsis sieboldii, and Ligustrum japonicum, which belong to the canopy layer, Pittosporum tobira and Ardisia japonica, which belong to the shrub layer and Trachelospermum asiaticum and Stauntonia hexaphylla, which belong to the vines, appearing in evergreen broad-leaved climax forest community, showed strong positive association(+) with each other. These tree species had a negative association or no friendly relationship with deciduous broad-leaved species due to the large difference in location environments. Divided into 4 group modularizations in the PSN sociogram, evergreen broad-leaved tree species in Group I and deciduous broad-leaved tree species in Group II showed high centrality and connectivity. It was analyzed that the arrangement of tree species (nodes) and the degree of connection (grouping) of the sociogram can indirectly estimate environmental factors and characteristics of plant communities like DCA. Tree species with high centrality and influence in the PSN included T. asiaticum, Eurya japonica, Lindera obtusiloba, and Styrax japonicus. These tree species are common with a wide range of ecological niches and appear to have the characteristics and survival strategies of opportunistic species that commonly appear in forest gaps and damaged areas. They will play a major role in inter-species interactions and structural and functional changes in plant communities. In the future, long-term research and in-depth discussions are needed to determine how these species actually influence plant community changes through interactions

• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.121-127
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• 2024

In this study, the applicability of replacing DG(Desulfurized Gypsum) from oil refinery with CCCMs(Carbon dioxide Conversion Capture Materials) as an ALC(Auto-claved LIghtweight Concrete) raw material was examined, and basic properties of ALC was measured. The main chemical components of DG and CCCMs were CaO and SO₃, and an increase in LOI(Loss of ignition) due to mineral carbonation reaction was verified. The crystalline phases of CCCMs were CaCO₃, CaSO₄, Ca(OH)₂, and CaSO₄·2H₂O. When DG, a raw material for ALC production, was replaced with CCCMs, foaming height, pore shape, absolute dry gravity, and compressive strength results measured similar for all binders. In addition, the formation of tobermorite which is main crystalline phase of ALC was shown for all specimens in microstructural analysis.

• Journal of the Korean Geotechnical Society
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• v.36 no.11
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• pp.97-106
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• 2020

Swelling properties and shear strength behavior of MgO-Sand mixtures with hydration procese of MgO are compared according to different MgO contents (W_MgO/W_Total=0, 30, 50, 70, 100%) in this study. The specimens are prepared by mixing with crushed MgO refractory bricks and silica sand. After hydration, the particle size and the specific gravity of MgO were decreases. Through microstructure observation and X-ray diffraction analysis, it is confirmed that MgO changes from the cubic structure of Periclase to the hexagonal cubic structure of Brucite after hydration. As the MgO content increases, both swelling rate and swelling pressure of the mixtures increase. W_MgO/W_Total=30% specimen shows relatively low swelling pressure and swelling rate because produced Mg(OH)₂ mainly fills the pores between sand particles. However, in the case of MgO more than 50%, swelling pressure and swelling rate increase significantly because Mg(OH)₂ fills the pores of sand particles at first and then either pushes out sand particles or Mg(OH)₂ particles after filling the pores. As a result of the direct shear test, before hydration, the mixtures show a dilative behavior on high MgO contents and a contractive behavior on low MgO contents. However, after hydration, the behavior of all mixtures changes to contractive behavior. The threshold fraction of fine (i.e., Mg(OH)₂) contents of the hydrated MgO-Sand mixtures reveals approximately 60% compared with normalized shear strength.

• Journal of Food Hygiene and Safety
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• v.32 no.1
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• pp.57-63
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• 2017

Foreign materials with a variety of types and sizes are found in food; thus, extraordinary efforts and various analytical methods are required to identify the types of foreign materials and to find out accurate causes of how they unintentionally enter food. In this study, human, cow, pig, mouse, duck, goose, dog, and cat were chosen as various types of animal hairs because they can be frequently incorporated into food during its production or consumption step. We morphologically analyzed them using stereoscopic, optical, SUMP method, and scanning electron microscopes, showing differences in each type. In addition, X-ray fluorescence spectrometer (XRF) was used to analysis chemical compositions ($^{11}Na{\sim}^{92}U$, Mass%) of samples. As a result, we observed that mammalian hairs were mainly composed of sulfur. Organic compounds of samples were further analyzed by fourier transform infrared spectroscopy (FT-IR) that can compare spectra of given materials; however, this method did not show significant differences in each sample. In this study, we suggest a rapid method for the identification of the causes and types of foreign materials in food.

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.28-36
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• 1996

The pentanuclear complexes have been obtained by the reactions of molybdenum(VI) and tungsten(VI) polynuclear complexes with molybdenum(O) and tungsten(O) dinitrosyl mononuclear complexes, and methylthioamidoxime. The prepared complexes (n-Bu4N)2[Mo4O12Mo(NO)2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2](1), (n-Bu4N)2[W4O12Mo(NO)2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2](2), (n-Bu4N)2[Mo4O12W (NO)2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2] (3) have been characterized by elemental analysis, infrared, UV-visible and 1H NMR spectra. The complexes are elucidated the cis-{M(NO)2}2+(M = Mo, W) unit and a slight delocalization by spectroscopy. The structure of (n-Bu4N)2[W4O12Mo(NO) 2{CH3SCH2C(NH2)NHO}2{CH3SCH2C(NH)NO}2] was determined by X-ray single crystal diffraction. Crystal data are follows: Monoclinic, $P21}a$, a = 22.14(2) $\AA$, b = 14.93(1) $\AA$, c = 23.20(1) $\AA$, $\beta$ = 111.08(6) $\AA$, V = 7155(9) $\AA$, Z = 4, final R = 0.072 for 6191(I > $3\sigma(I)).$ The structure of complex forms two dinuclear [W2O5{CH3SCH2C(NH2)NHO}{CH3SCH2C(NH)NO}] and a central {Mo(NO)2} 2+ core. The geometric structure of the {Mo(NO)2} 2+unit is the formally cistype and C2v symmetry.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.129-138
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• 2006

Helicopter-borne aeromagnetic surveys at two different times separated by three years were conducted to better understand the shallow subsurface structure of the Vulcano and Lipari volcanic complex, Aeolian Islands, southern Italy, and also to monitor the volcanic activity of the area. As there was no meaningful difference between the two magnetic datasets to imply an apparent change of the volcanic activity, the datasets were merged to produce an aeromagnetic map with wider coverage than was given by a single dataset. Apparent magnetisation intensity mapping was applied to terrain-corrected magnetic anomalies, and showed local magnetisation highs in and around Fossa Cone, suggesting heterogeneity of the cone. Magnetic modelling was conducted for three of those magnetisation highs. Each model implied the presence of concealed volcanic products overlain by pyroclastic rocks from the Fossa crater. The model for the Fossa crater area suggests a buried trachytic lava flow on the southern edge of the present crater. The magnetic model at Forgia Vecchia suggests that phreatic cones can be interpreted as resulting from a concealed eruptive centre, with thick latitic lavas that fill up Fossa Caldera. However, the distribution of lavas seems to be limited to a smaller area than was expected from drilling results. This can be explained partly by alteration of the lavas by intense hydrothermal activity, as seen at geothermal areas close to Porto Levante. The magnetic model at the north-eastern Fossa Cone implies that thick lavas accumulated as another eruption centre in the early stage of the activity of Fossa. Recent geoelectric surveys showed high-resistivity zones in the areas of the last two magnetic models.

• Land and Housing Review
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• v.14 no.4
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• pp.17-37
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• 2023

The rental housing market in South Korea, specifically monthly rent with deposit, has been expanding over the last three decades (8.2% in 1990 to 21.0% in 2020), partly replacing the traditional Jeonse market. The distribution of rent has changed due to public rental subsidies and the emergence of luxury rental housing, while the distribution of rental household income has been polarized because of the emergence of rich renters. This study attempts to measure the structural changes in the rental market by developing a new indicator of income-rent mismatch. Using the seven series of the Korea Housing Survey, this study analyzed the changes in rent (reflecting the conversion rate) and income levels of rental households in 2006 (base year) and 10-15 years later (the analysis year) at the national level and at the spatial unit of 16 metropolitan cities and provinces (excluding Sejong), respectively, by dividing them into quartile data. The result reveals that rental housing was undersupplied in middle- and high-income rental housing due to the decline in the highest quartile (25%→18%) and the third quartile groups (25%→20%), while the supply of public rental housing expanded for the second quartile (25%→28%) and the lowest quartile (25%→35) groups. On the demand side, the highest income quartile shrank (25%→21%), while the lowest income quartile grew (25%→31%). Comparing the 16 metropolitan cities and provinces, there were significant regional differences in the direction and intensity of changes in rent and renter household income. In particular, the rental market in Seoul was characterized by supply polarization, which led to an imbalance in the income distribution of rental households. The structural changes in the apartment rental market were different from those in the non-apartment rental market. The findings of this study can be used as a basis for future regional rental housing markets. The findings can support securing affordable rental housing stock for each income quartile group on monthly rent and developing housing stability measures for a balance between income and rent distribution in each region.

• Sijohaknonchong
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• v.30
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• pp.263-300
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• 2009

Adoration for nature constitutes one of the primary subjects that literature has tackled since the origin of human history. Nature expressed through a poet's subjective imagination is the internalized and reorganized nature. This study examines the view on nature enacted in Ch'o-Jung's three-verse poems (sijo) in light of the traditional views on nature implicated in the ancient three-verse poems (koshijo), which is in line with the long-established Oriental view on nature. To dignitaris(sadaebu) in the Chosun Dynasty, nature appeared as the idealistic subject for moral culture ($shims{\breve{o}}ngsuyang$), which also becomes the literary space where the purity and justice of the world view of Neo-Confucianism(Sungrihak) is contained in the form of the three-verse poem, the lyrical poetic space where the "I" is united with nature by way of "enjoying of wind and moon"($umpungnongw{\breve{o}}i$) and "living in quiet retiremen"($yuyuchaj{\breve{o}}k$), and the object for the poetical perception of the surrounding world. Ch'o-Jung' s three-verse odes are found in Reed pipe ($Ch'oj{\breve{o}}k$), Sixty Five Pieces of Three-Verse Odes (Samhaengshi-$yukshipopy{\breve{o}}n$), Autumn Fragrance ($Hyangginam{\check{u}}n-ga{\check{u}}l$), and The Words of Zelko va Tree ($N{\check{u}}tinamu{\check{u}}i-mal$). This study analyzes 212 pieces of Ch'o-Jung' s three-verse poems chosen from theses books. In Ch'o-Jung's poems, the traditional view on nature expressed in the ancient three-verse poems is rendered in such a way that metaphysical understanding of nature is indirectly transmitted through the objective correlatives found nature. Nature is no longer the object of straightforward utterance, but transformed, displaced, and removed: that way, nature gets objectified to form a complicated and multi-layered structure. In conclusion, the view on nature manifested in Ch'o-Jung's three-verse poems is based on traditional metaphysics. Second, nature is the object of lyrical nostalgia and adoration. Third, nature is imbued with the fundamental affection for parents. Fourth, nature is associated with organic life. Fifth, the nature in Ch'o-Jung's poems reveals the beauty of stillness endorsed in Lao-tse's and Chung-tze's philosophy. And last, nature is the agent for self-realization and meditation.

• 한국지구물리탐사학회:학술대회논문집
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• 2002.09a
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• pp.139-162
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• 2002

Since weak zones or geological lineaments are likely to be eroded, weak zones may develop beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. Dc resistivity surveys, however, have seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of case histories, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing at the water bottom, since the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the dc resistivity method can provide the fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio data as well as the high resolving power. The method installing electrodes at the water bottom is suitable to the detailed survey because of much higher resolving power, whereas the method floating them, especially streamer dc resistivity survey, is to the reconnaissance survey owing of very high speed of field work.