• Title/Summary/Keyword: formation age

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Gas dynamics and star formation in dwarf galaxies: the case of DDO 210

  • Oh, Se-Heon;Zheng, Yun;Wang, Jing
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.75.4-75.4
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    • 2019
  • We present a quantitative analysis of the relationship between the gas dynamics and star formation history of DDO 210 which is an irregular dwarf galaxy in the local Universe. We perform profile analysis of an high-resolution neutral hydrogen (HI) data cube of the galaxy taken with the large Very Large Array (VLA) survey, LITTLE THINGS using newly developed algorithm based on a Bayesian Markov Chain Monte Carlo (MCMC) technique. The complex HI structure and kinematics of the galaxy are decomposed into multiple kinematic components in a quantitative way like 1) bulk motions which are most likely to follow the underlying circular rotation of the disk, 2) non-circular motions deviating from the bulk motions, and 3) kinematically cold and warm components with narrower and wider velocity dispersion. The decomposed kinematic components are then spatially correlated with the distribution of stellar populations obtained from the color-magnitude diagram (CMD) fitting method. The cold and warm gas components show negative and positive correlations between their velocity dispersions and the surface star formation rates of the populations with ages of < 40 Myr and 100~400 Myr, respectively. The cold gas is most likely to be associated with the young stellar populations. Then the stellar feedback of the young populations could influence the warm gas. The age difference between the populations which show the correlations indicates the time delay of the stellar feedback.

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The Effect of Role Ply by Animation on Young Children's Self-Concept (동화를 이용한 역할놀이가 유아의 자아개념 형성에 미치는 영향)

  • 이정숙
    • Journal of Families and Better Life
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    • v.14 no.4
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    • pp.163-174
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    • 1996
  • The purpose of this study was to examine the effects of children's role play by animatino on self-concept formation, The subjects of this study were 20 children of a kindergarten located in Gunpo City. the mean age were 5.5 years. Children were assigned to the study group and the control group. The children in the study group had role play of which the main themes were positive self-comcept formation but the children in control group did not have any role play by animation. The result showed 1. Role play by animation influenced on children's positive self-concept. 2. There was a difference in self-concept test score: The self-image attitude to the kindergatrten and attitude to the group of peer. Role play by animation influenced on the self-image and attitude to the group of peer. But attitude to the Kindergarten score was not increased significantly. 3. Role play by animation influenced on chikren's catharsis of emotion.

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Modulation of Neural Circuit Actvity by Ethanol in Basolateral Amygdala

  • Chung, Leeyup
    • Development and Reproduction
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    • v.16 no.4
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    • pp.265-270
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    • 2012
  • Ethanol actions in the amygdala formation may underlie in part the reinforcing effects of ethanol consumption. Previously a physiological phenomenon in the basolateral amygdala (BLA) that is dependent on neuronal network activity, compound postsynaptic potentials (cPSPs) were characterized. Effects of acute ethanol application on the frequency of cPSPs were subsequently investigated. Whole cell patch clamp recordings were performed from identified projection neurons in a rat brain slice preparation containing the amygdala formation. Acute ethanol exposure had complex effects on cPSP frequency, with both increases and decreases dependent on concentration, duration of exposure and age of the animal. Ethanol produces complex biphasic effects on synaptically-driven network activity in the BLA. These findings may relate to subjective effects of ethanol on arousal and anxiolysis in humans.

Modeling of Setting Behavior in Fresh Concrete considering Microstructure Formation

  • Cho, Ho-Jin;Song, Ha-Won;Byun, Keun-Joo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.490-493
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    • 2004
  • In the analysis of early-age concrete behavior, the fresh concrete is considered as a structural element immediately after mixing. But for the activation of real structural behavior in the fresh concrete, the so-called setting time is necessary a few hours after the beginning of hydration reaction. In this paper, analysis on the setting behavior is carried out by proposing an analytical model based on the percolation theory as well as the expanding cluster model by defining the setting as a microstructure formation in fresh concrete. An experimental investigation is also carried out to show the influences of curing temperature, mineral admixtures and chemical admixture on setting behavior of fresh concrete. Finally, the analytical results using proposed model are compared with the experimental results for the sake of verification.

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Discussion on the Quaternary fault movement at Yugye-ri area in the northern part of Yangsan Fault (양산단층 북부 유리계 일대의 신기 단층운동 소고)

  • 경재복
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.04a
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    • pp.66-73
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    • 2001
  • Yangsan fault in the southeastern part of Korean peninsula has been locally reactivated along a prexisted fault during the late Pleistocene time. Geomorphological evidence of the reactivation is revealed at the northern segment(Yugye-ri, Tosung-ri areas) of the Yangsan fault. The reactivation is distinctively characterized by fault gouge and fracture zone with high frequency in the Yugye-ri area. Obique slip separation of the area is about three meters of the middle terrace. The cumulative vertical displacement is recognized after the formation of the middle terrace. Age of the reactivated faulting is constrained to during the formation of dissected valley deposits. Average vertical slip based on paleo-event is inferred to about 0.5-0.7 meter in this area.

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Geology and Ore Deposits of Yeonhwa Mine (연화광산(蓮花鑛山)의 지질광상(地質鑛床))

  • Han, Kap Soo
    • Economic and Environmental Geology
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    • v.2 no.3
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    • pp.47-57
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    • 1969
  • The Yeonhwa Lead and Zinc Mine is located in northern part of Kyeongsang-Buk-Do, Korea, and is economically most important mine because it produces most part of the output of lead and zinc minerals in the country. Ore deposits of the mine are localized in the Pungchon Formation and several limestone seams of upper Myobong Formation in Cambrian Age. Ore solution ascended along the fractures of N-S, NE-SW or NW-SE trends and along slate and limestone boundary, and then replaced selectively limestone to make ore bodies. Skarn minerals are consisted of hedenbergite, diopside, and main sulfide mineral orebodies are composed of galena, zincblende, pyrrhotite, pyrite and a minor amounts of arsenopyrite and chalcopyrite. Metal ratio, ${\rho}_{Pb}={\frac{Pb(%)}{Pb(%)+Zn(%)}}{\times}100$, illustrates the zona I arrangements of some ore bodies. It will be inferred the flow trending of ore solution and the process reaction with adjacent country rocks. The sub-divided formations of the Pungchon limestone and Myobong slate are very useful as a criteria for detecting probable ore location. Rhodochrosite veins are good evidence for searching of ore location, especially on Pb-rich ore bodies.

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A Study on the Process of Forming Peer Relations between Students with Disabilities and Non-disabled Students

  • Cho, Woo-Hong;Joo, Young-Shin
    • Journal of the Korea Society of Computer and Information
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    • v.22 no.10
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    • pp.189-194
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    • 2017
  • The purpose of this study was to find out the necessary conditions and factors what effect as a society member through the students with disabilities to have a positive and mutual peer relationship with their classmates in the school and by them analyzed formation process and elucidate signification. The research method focused on the data summarized and enumerated through the investigation methods such as two in-depth interviews and two observation activities part, and the data which are commonly stated or observed in the data. The results of this study start that the factors of peer relationship formation between children with disabilities and their with non-disabled children are caused by lack of prejudice or lack of awareness. However, continuous cognizance improvement program, teacher's education guidance, the age have presence sense and subject about friend equating idea was mainly shown of school education or local community.

Histological and Morphological Characteristics of New and Latent Bud Formation in Panax ginseng C.A. Meyer (인삼의 신아 및 잠아발생의 조직 형태적 특성)

  • 정찬문;정열영
    • Journal of Ginseng Research
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    • v.19 no.3
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    • pp.281-286
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    • 1995
  • This experiment was conducted to obtain the basic information on new- and latent-bud formation, and stem vestige arrangement on the rhizome of Panax ginseng C.A. Meyer. Latent buds emerged from meristematic region between shoot and root of the embryo, and new buds for the next year were distributed both at the bottom portion of the stem and the rhizome. In the new buds, organs such as leaf, stem, and flower bud were already completely differentiated, while the latent bud had an undifferentiated meristematic tissue arranged linearly in a vertical line, indicating that each year new- and latent-buds are formed successively. This result suggests that the number of stem vestige may be used for the determination of ginseng age. Key words Rhizome, new-bud, latent-bud, histology, morphology, stem vestige, vestige arrangement.

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Age and Growth of Flathead Grey Mullet Mugil cephalus Collected by a Two-side Fyke Net in the Coastal Water off Taean, Korea (태안 연안에서 이각망에 의해 채집된 숭어의 연령과 성장)

  • Hong, Jimin;Yoon, Jae Seon;Lee, Tae Won
    • Korean Journal of Ichthyology
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    • v.26 no.3
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    • pp.194-201
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    • 2014
  • Age and growth of flathead grey mullet Mugil cephalus were estimated using samples collected by a two-side fyke net in the coastal water off Taean in 2008. Age was determined by examination of annuli in otoliths and total lengths at ages were back-calculated from otolth-body size relationship. Total length ranged from 239 to 605 mm and mainly between 400 and 550 mm. Observed ages ranged from 1 to 7 years old and mainly between 3 and 5 years old. Total length (L, mm) was linearly related to otolith radius (R, mm); L=15.3+87.9 R. Total lengths at the annulus formation in otolith were back-calculated by Frazer-Lee method. Estimated length at the age 1 was $316{\pm}40.6mm$ ($mean{\pm}SD$) showing a fast growth rate during the early growth stage. Total length at each age (t) showed a wide range indicating the big difference in growth rate among individuals. Growth in total length can be expressed by a Von Bertalanffy growth curve as $L_t=542[1-{\exp}\{-0.493 (t+0.769)\}]$.

Phase Transformation and Mechanical Properties of 14 K White Gold Alloys by Heat Treatments

  • Yun, Don-Gyu;Seo, Jin-Gyo;An, Yong-Gil;Sin, So-Ra;Han, Dong-Seok;Park, Jong-Wan
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.283-283
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    • 2013
  • Because of beautiful glossy and color, the value of gold leverage is very high in Europe. To improve the quality of gold alloys, we performed heat treatment on 14 K white gold alloys by variously changing age-hardening conditions. Age-hardening behavior and the related phase transformation changes were studied to elucidate the hardening mechanism of 14 K white gold alloy. For solid solution treatment [ST], casted gold alloy specimens were treated at high temperature ($750^{\circ}C$) for 30 minutes, and the specimens dropped to water to quench them. For Age-hardening treatment [AT], the specimens were treated at various temperatures ($250{\sim}300^{\circ}C$). After the heat treatment, we observed the phenomenon to increase hardness from 126 Hv to 166 Hv by Vicker's hardness tester. Through electron probe micro-analysis (EPMA) mapping analysis, we investigated that irregular particles were changed uniformly. In the SEM and OM images, two phases of matrix and particle-likestructures were observed, and the precipitation of these elements from the matrix progressed during age-hardening. By transmission electron microscope and X-ray diffraction observation, it was revealed that the formation of the Au3Cu superstructure contributed to the age-hardening at $270^{\circ}C$ in the gold alloy. After the heat treatment, this analysis shows that casted gold alloys were to improve hardness and to moderate surface defects at specific temperatures and duration.

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