• Journal of the Mineralogical Society of Korea
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• v.24 no.1
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• pp.19-29
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• 2011

Clay mineral assemblages of core PC25A collected from the northern part of the Aleutian Basin in the Bering Sea were examined in order to investigate changes in sediment provenances and transport pathways. Ages of core PC25A were determined by both Last Appearance Datum of radiolaria (L. nipponica sakaii; $48.6{\pm}2\; ka$) and age control points obtained by the correlations of $a^{\ast},\; b^{\ast}$, and laminated sediment layers with the adjacent core PC23A, whose ages are well constrained. The corebottom age of core PC25A was calculated to be about 57,600 yr ago and core-top might be missing during coring execution. Average contents of smectite, illite, kaolinite, and chlorite during the last glacial period are 11% (5~24%), 47% (36~58%), 13% (9~19%), and 29% (21~40%), respectively. Clay mineral assemblages of the last glacial period are characterized by higher illite and lower smectite contents than those of core MC24 representing the modern values. Illite-rich clay sediments during the warm Early Holocene were transported from the northern part of Alaska continent (Province 1) through the ice-melt waters. During the deglacial period (B${\phi}$lling-All${\phi}$rod) of MIS 2, clay-sized particles seemed to be also transported by ice-melt waters mainly from Province 2 and Province 3 located farther south than Province 1. Higher smectite content during the Last Glacial Maximum is attributed to increased amounts of clay particles from the adjacent Alaska Peninsula (Province 4). From the early to the middle MIS 3, illite and smectite contents decreased, whereas chlorite content increased. With the low sea level standing during MIS 3 the supply of clay sediments from Province 2 and Province 3 was most likely intensified. Changes in clay mineral assemblages of core PC25A located in the northern part of the Aleutian Basin in the Bering Sea are closely related to the change of surface current system caused by sea level variation during the last glacial period.

• The Journal of the Petrological Society of Korea
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• v.1 no.1
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• pp.49-57
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• 1992

Whole rock and mineral ages for the Jecheon Granite distributed in the Ogcheon Fold Belt were dated by three radiometric methods, and its thermal history was elucidated as follows, on the basis of isotopic age data. Rb and Sr isotopic compositions of three whole rock and seven mineral concentrates made an isochron of 202.7${\pm}$ 1.9 Ma with a strontium initial ratio of 0.7140. Different age data of twelve mineral concentrates agree closely with the retention temperature of each mineral in K-Ar and Fission Track methods. The Jecheon granitic magma was generated by partial melting of crustal materials (S-type), or by mixins between mantle and crustal materials, intruded into the katazone or mesozone (7∼9 km) of the Ogcheon Fold Belt, at least in the Early Jurassic (about 203 Ma), and then crystallized and cooled down rapidly from about 600$^{\circ}C$ to 300$^{\circ}C$ (more than 20$^{\circ}C$/Ma), owing to thermal differences between the magma and the wall-rock. During the Middle to Late Jurassic (190∼140 Ma), the cooling of the granite was likely to stop and keep thermal equilibrium with the wall-rock. The severe tectonism associated with igneous activities and active weathering on the surface in Early to Late Cretaceous time (140∼70 Ma) might have accelerated the granite pluton to uplift rapidly (40∼60 m/Ma in average) up to 3∼4 km and cooled down from 300$^{\circ}C$ to 200$^{\circ}C$ (1.4 $^{\circ}C$/Ma). The granite pluton was likely to keep different uplifting and cooling rate of about 120 m/Ma and 5$^{\circ}C$/Ma in average from the Late Cretaceous to Early Tertiary (70∼50 Ma), and about 60 m/Ma and 2$^{\circ}C$/Ma in average from about 50 Ma up to the present, respectively.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.427-448
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• 2019

This study reconstructed the paleoenvironments and paleogeography of the Taebaeksan Basin, through a review of the previous researches on sedimentology, paleontology and stratigraphy. This study also carried out a sequence stratigraphic analysis on regional tectonism and sea-level fluctuations on the basin during the Early Paleozoic. The basin broadly occur in the Taebaek, Yeongweol-Jecheon, Jeongseon-Pyeongchang, and Mungyeong areas, Gangwon province, South Korea. The basin-fills are composed mainly of mixed carbonates and siliciclastics, divided into the Taebaek, Yeongweol, Yongtan, Pyeongchang and Mungyeong groups according to lithologies and stratigraphic characteristics. Recently, there are a lot of studies on the provenance and depositional ages of the siliciclastic sequences of the basin. The detrital sediments of the basin would be derived from two separated provenances of the core-Gondwana and Sino-Korean cratons. In the Early Cambrian, the Taebaek and Jeongseon-Pyeongchang platforms have most likely received detrital sediments from the provenance of the Sino-Korean craton. On the other hand, the detrital sediments of the Yeongweol-Jecheon platform was probably sourced by those of the core-Gondwana craton. This separation of provenance can be interpreted as the result of the paleogeographic and paleotopographic separation of the Yeongweol-Jecheon platform from the Taebaek and Jeongseon-Pyeongchang platforms. The analyses on detrital zircons additionally reveal that the separation of provenance was ceased by the eustatic rise of sea-level during the Middle Cambrian, and the detrital sediments of the Taebaeksan Basin were entirely supplied from those of the core-Gondwana craton. During that period, sediment supply from the Sino-Korean craton would be restricted due to inundation of the provenance area of the craton. On the other hand, the Jeongseon-Pyeongchang platform sequences show the unconformable relationship between the Early Cambrian siliciclastic and the Early Ordovician carbonate strata. It is indicative of presence of regional uplift movements around the platform which would be to the extent offset of the effects of the Middle to Late Cambrian eustatic sealevel rise. These movements expanded and were reinforced across the basin in the latest Cambrian and earliest Ordovician. After the earliest Ordovician, the basin was tectonically stabilized, and the shallow marine carbonate environments were developed on the whole-platform by the Early Ordovician global eustatic sea-level rise, forming very thick carbonate strata in the basin. In the Late Ordovician, the Early Paleozoic sedimentation on the basin was terminated by the large-scale tectonic uplift across the Sino-Korean platform including the Taebaeksan Basin.

• Korean Journal of Childcare and Education
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• v.11 no.1
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• pp.305-327
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• 2015

The purpose of this study was to investigate the tendencies and general distributive features of creativity elements on activities in the Nuri curriculum teachers' guidebooks for the ages of 3-5. This was done by analysis of 1,883 activities related to creativity in the teachers' guidebooks. In order to analyze the data, the frequency and percentage of creativity elements were calculated. The results can be summarized as follows: First, the ratio of activities related to creativity was 95.1% for the age of three, 93.1% for the age of four, and 78.6% for the age of five. Second, the most common creativity element was cognitive element and the next was motivational element, and the least was dispositional element. Third, regarding themes, the frequency of creativity elements was highest in 'tools for living', and lowest in 'countries of the world'. Fourth, the creativity elements were more frequently found in group activities rather than free choice activities. Last, the frequency of creativity elements was highest in nature exploration, and was followed by social relations. The results of this study could be used as basic data for practicing activities related to creativity in the field of early childhood education.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.15-24
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• 2007

The purpose of this study was to evaluate the presence and differential expression of connexin isoforms in the efferent ductules (ED) of male rat reproductive tract during postnatal development. Total RNA was isolated from the ED collected from rats at 1 week, 2 weeks, 1 month, 3 months, and 6 months of ages. Expression of six connexin mRNAs of 14 isoforms tested was detected by semi-quantitative RT-PCR. Fluctuation of mRNA levels of connexins 26 and 30 was found according to ages. A significant decrease of connexin 31.1 mRNA level was observed in the ED at 1 month of age. The highest levels of connexin 37 and 45 mRNAs were detected in the ED of early developmental period, while the expression of connexin 43 was the lowest at 1 week of age. The present study demonstrates differential regulation on expression of connexin isoforms in the rat ED in age-dependent manner.

• The Journal of Engineering Geology
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• v.8 no.2
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• pp.175-188
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• 1998

This paper describes the internal structures and K-Ar ages of fault gouges collected from the Dongnae fault zone. This fault zone is internally zoned and occurs in the multiple fault cores. A fault core consists of thin gouge and narrow cataclastic zones that are bounded by a much thicker damage zone. Intensity of deformation and alteration increases from damage zone through cataclastic zone to gouge zone. It is thought that cataclasis of brittle deformation was the dominant strain-accomodation mechanism in the early stage of deformation to form the gouge zone and that crushed materials in the regions of maximum localization of fault slip subsequently moved by cataclastic flow. Deformation mechanism drastically changed from brittle processes to fluid-assisted flow along the gouge zone as the high porosity and permeability of pulverzied materials during faulting facilitated the influx of the hydrothermal fluids. Subsequently, the fluids reacted with gouge materials to form clay minerals. Fracturing and alteration could have repeatedly taken place in the gouge zone by elevated fluid pressures generated from the reduction of pore volume due to the formation of clay minerals and precipitation of other materials. XRD analysis revealed that the most common clay minerals of the gouge zones are illite and smectite with minor zeolite and kaolinite. Most of illites are composed of 1Md polytype, indicating the products of hydrothermal alteration. The major activities of the Dongnae fault can be divided into two periods based upon K-Ar age data of the fault gouges : 51.4∼57.5Ma and 40.3∼43.6Ma. Judging from the enviromental condition of clay mineral formation, it is inferred that the hydrothermal alteration of older period occured at higher temperature than that of younger period.

• Ecology and Resilient Infrastructure
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• v.4 no.3
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• pp.149-155
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• 2017

Willow plants are representative biomaterials used in river restoration and main target trees in stream managements. In order to understand the changes in the growth of Salix subfragilis and S. chaenomeloides with their stand ages, we investigated the density, height and basal area of stems and biomass at their different aged stands of the riparian zone of the sand-bed stream, the Nakdong River, Korea. We also developed allometric equations for estimating the biomass of these two species by establishing the relationship between diameter at breadth height and tree height with above-ground biomass. The stem density showed a sharp decrease for 3 years after germination for S. subfragilis and 6 years for S. chaenomeloides, resulting in strong self-thinning. The stem height of the two species increased to 7.5 m in 15 years for S. subfragilis, and to 14 m in 13 years for S. chaenomeloides. Aboveground biomass also increased rapidly at the early stage of growth. The biomass increased to 17 ton DM/ha in 13 years for S. subfragilis and to 1,110 ton DM / ha in 13 years for S. chaenomeloides. It is expected that the allometric equations of two Salix species derived from this study will be applied to the objectively estimating the biomass of willow plants for the management of floodplain trees in streams.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.170-180
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• 2011

The purposes of this study are to find out the effectiveness of the tutoring program and the level of self-regulated learning ability in tutoring program attending students. This study has been performed for team-tutoring program attending students(n=183) who are in 15 department, D college in Daegu. Following results were drawn thought correlation analyses of variables obtained during the survey period. The results were as follows; There was statistically significant difference among perception controlling ability, purpose controlling ability, and action controlling ability. In over 20 ages, organization, meta-perception stratagem, arrangement, self-effectiveness, controlling learning time ability were higher than of lower 20 ages(p<0.05). In tutors, demonstration, organization, meta-perception stratagem, arrangement, checking, purpose intentions, self- effectiveness, achievement, controlling action, help requirement ability were higher than tutees(p<0.05). As results, the tutoring program was effective for both tutors and tutees in college students. Further studies in an education program for students in all years should be implemented to examine tutoring effects. Implementation of tutoring should address the frustrations and difficulties encountered by the students to facilitate better outcomes.

• Journal of Chest Surgery
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• v.31 no.12
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• pp.1217-1221
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• 1998

Background: The advent of EEA stapler has lowered the leakage rate of esophagogastric anastomoses and thereby contributed to a decrease in the operative mortality of the easophageal resection. Recent surgical reports, however, have documented 10% to 20% prevalence of benign anastomotic stricture formation after the use of EEA stapler to construct an esophagogastric anastomosis. We analyzed the cases of anastomotic strictures to reduce the incidence of anastomotic strictures with EEA stapled esophagogastrostomy. Material and Method: EEA stapled esophagogastrostomy was performed in 195 parients during the period of over 11 years from Jan. 1986 to Dec. 1996 in Kosin Medical Center. Ten patients of them died in the early postoperative days. In the remaining 185 patients, we studied the incidence and the onset time of anastomotic strictures, relationship between the patients' ages, the anastomotic sites, and the size of the cartridges with incidence of anastomotic stricture. We also studied the method of treatment and its effect in the anastomotic strictures. Result: Benign anastomotic strictures occurred in 39 cases among 185 patients(21%), 25 cases(64.1%) of the 39 cases developed in one to three months postoperatively. The patients' ages and the anastomotic sites did not effect with the incidence of anastomotic stricture, but high incidence of anastomotic stricture in EEA stapled esophagogastrostomy(p=0.04)was observed in small cartridge sizes. One or two balloon dilatation(89%) relieved the anastomotic strictures. Conclusion: We conclude that a larger size cartridge is recommended in EEA stapled esophagogastrostomy to reduce the incidence of anastomotic stricture if possible, and one or two balloon dilatation would seem to be a safe and reliable method in treating anastomotic stricture when the anastomotic stricture was occurrs.

• Korea journal of population studies
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• v.18 no.2
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• pp.115-168
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• 1995

It is a common wisdom that the long-term economic development of Korea chiefly depends not only on the steady increase of the capital formation but also on the stable increase of the national saving. And also it is a widely accepted opinion that household saving plays a significant role for the smooth supply of investment funds. For the empirical analysis on the determining factors of household saving, consumption function of the household of Korea was utilized indirectly. The reason is that consumption function is regarded as a stable function whereas saving function is considered to be an unstable function of the relevant independent variables. In order to carry out the regression process of the consumption functions, data on the family income and expenditure survey and the farm household economy survey was used. The regression result could be summarized as follows : Firstly, household income and the number of the employed in the household have the negative effect in determining the consumption ratio of the Korean households. On the other hand, ages and the educational attainment of the household heads as well as the number of the household members have the positive effect. During the early part of 21st century, the consumption ratio of the Korean households is expected to be decreased because of the increasing trend of household income, and the ever increasing number of the employed member of the household based on the increasing trend of the labor force participation rate of women and the decrease of the average size of the number of household members owing to widespread nuclear family system. On the other hand, the consumption ratio of the household of Korea is expected to be increased because of the continuous increase of the average ages of the household heads caused by the population aging phenomena and improvement of the educational attainment of the household heads. But on the whole, household saving ratio is expected to be increased owing to the secular downward trend of the consumption and therefore no significant difficulties are anticipated for the smooth provision of investment resources needed to have long-term economic progress of Korea.