• Title/Summary/Keyword: Origins

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Dynamic Heterogeneity in Spin Facilitated Model of Supercooled Liquid: Crossover from Fragile to Strong Liquid Behavior

  • Choi, Seo Woo;Kim, Soree;Jung, YounJoon
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.183-195
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    • 2014
  • Kinetically constrained models (KCM) have attracted interest as models that assign dynamic origins to the interesting dynamic properties of supercooled liquid. Signs of dynamic heterogeneity in the crossover model that linearly interpolates between the FA-like symmetric constraint and the East model constraint by asymmetric parameter b were investigated using Monte Carlo technique. When the asymmetry parameter was decreased sufficiently, smooth fragile-to-strong dynamic transition was observed in terms of the relaxation time, diffusion constant, Stokes-Einstein violation, and dynamic length scale. Competition between energetically favored symmetric relaxation mechanism and entropically favored asymmetric relaxation mechanism is behind such transition.

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Reduction of Electromagnetic Torque Ripple in High-Speed, High-Load Brushless DC Motors used for Automobile Parts (자동차 부품용 고속, 고부하 BLDC 모터내의 전자기적 토크 맥동 저감)

  • 황상문
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.4
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    • pp.39-46
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    • 1998
  • For permanent magnet brushless DC motors used for high speed fuel pumps, torque ripple is an important origin of vibration, acoustic noise and speed fluctuation. In this paper, the output torque profile of a PM motor with one phase energized is decomposed into the commutation torque, the reluctance torque and the armature reaction torque according to their source origins. It verifies that the output torque profile is qualitatively equivalent to the BEMF profile for low reluctance motors. This paper discusses the effect of magnet pole shaping and magnet arc length on the output torque and torque ripple. A magnet edge shaping is proposed to design a trapezoidal BEMF motor without torque ripple, with minimal sacrifice of the maximum output torque.

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Perspectives on Embryo Biotechnology: Its Origins, Current Uses and Future Prospects

  • Betteridge, Keith J.
    • Proceedings of the KSAR Conference
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    • 2001.10a
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    • pp.5-5
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    • 2001
  • This lecture will begin by tracing some of the history behind techniques that we nowadays take for granted in the practice of embryo transfer, and in the application of the technique to various animal biotechnologies. It will be argued that an appreciation of such history can teach us a great deal about how we need to study and teach the subject, and about the best ways to conduct and finance the research that is essential to further progress. Examples in support of this argument will be taken from the changes that have occurred in the way embryos, particularly bovine embryos, have been collected, maintained in vitro, subjected to a variety of manipulations (sexing, division to produce identical animals, combination into chimeras, transfection with foreign genes), frozen and thawed, and transferred over the past 50 years. (omitted)

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Electrodermal Activity as an Indicator of Emotional Processes

  • Boucsein, Wolfram
    • Science of Emotion and Sensibility
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    • v.2 no.1
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    • pp.1-25
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    • 1999
  • The differentiation of emotions by means of psychophysiological measures has been only moderately successful so far. A major reason for this dilemma may be the lack of appropriate neurophysiological modeling for the various autonomic nervous system based measures being used in emotion research. The aim of the present article is to provide such a neurophysiological background for electrodermal activity which has been frequently used as an indicator of emotional processes. First, the literature is reviewd with respect to the usability of electrodermal measures as an indicators of emotion. second, the neurophysilogical sources of electrodermal phenomena in general are described. Electrodermal activity has different origins in the central nervous system, a limbic-hypothalamic source that dominates during negative emotions as opposed to a premotor and basal ganglia source being predominantly active during positive emotions. Panksepp's model of four basic emotive systems is adopted for demonstrating subcortical structures and pathways possibly involved in the elicitation of both kinds of electrodermal activity in comparison with cardiovascular in dicators of emotional processes.

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데모그라피의 역사적 배경과 한국인구의 지역적 편향분포의 지니 계수적 해석

  • 구자흥;이성철
    • Journal for History of Mathematics
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    • v.16 no.2
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    • pp.103-116
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    • 2003
  • Now we have faced to two fundamental population problems: The one is over-population problem in proportion to the nation's total area, 99,434 $km^2$, and the other is unbalanced population distributions in the provincial districts of administration (16th local governments). For example, the population density of Seoul city is 16,335 persons, and the nations population density of South Korea is 464 persons for 1 km$^2$. At the first part of this study, we introduced the origins and historical back grounds of Formal Demorgraphy. And the second part, we suggest some useful indicators of urbanization of rural populations in terms of Gini's Coefficients of Concentration. As the result, we can show that the ecological Gini's Coefficients of Concentration, during the periods covered by this study, have been increasing extraordinary: 0.349, 0.433, 0.532, 0.581, 0.633 and 0.626 in 1970, 1980, 1985, 1990, 1995, 2000 A.D. respectively. However, the trend of urbanization (concentration of population) of Korean population has been the relative equilibrium state of 0.63 from 1995 to 2000 A.D.

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유기용매 내에서 중쇄지방질의 합성

  • Gwon, Dae-Yeong
    • Bulletin of Food Technology
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    • v.7 no.2
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    • pp.64-73
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    • 1994
  • Using 20 lipases from various microbial origins medium chain glycerides, namely, mono-, di-, and tri-carproyl glycerols from glycerol and acid were synthesized in isooctane. Enzyme reaction was performed at 0.35 M of capric acid, 0.025M of glycerol and the same mass of silica gel to remove water in 5ml of isooctane with 30mg of lyophilized lipase. Among 20 lipases, eleven lipases showed good synthetic activities, especially lipase from Pseudomonas aeruginosa (Lipase PS), Rhizomucor miehei origined lipase and Chromobacterium viscosum lipase (Lipase CV) showed good activities for production of tricaproylglycerol, while Lipase OF-360 (origined from Candida rugosa) and Lipase D (Rhizopus delemar) were good for production of dicaprolyglycerol. The lipases, especially Lipase PS, have high thermal stability at $ 60^{circ}C$, and optimum pH of lyophilization for dehydrating the lipase was pH 6.5.

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The interaction between gut microbiome and nutrients on development of human disease through epigenetic mechanisms

  • Lee, Ho-Sun
    • Genomics & Informatics
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    • v.17 no.3
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    • pp.24.1-24.8
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    • 2019
  • Early environmental exposure is recognized as a key factor for long-term health based on the Developmental Origins of Health and Disease hypothesis. It considers that early-life nutrition is now being recognized as a major contributor that may permanently program change of organ structure and function toward the development of diseases, in which epigenetic mechanisms are involved. Recent researches indicate early-life environmental factors modulate the microbiome development and the microbiome might be mediate diet-epigenetic interaction. This review aims to define which nutrients involve microbiome development during the critical window of susceptibility to disease, and how microbiome modulation regulates epigenetic changes and influences human health and future prevention strategies.

Thermal Electret of the ZnO varistor (ZnO 바리스터의 열 일렉트렛트)

  • Ahn, Y.M.;Lee, S.S.;Park, S.H.;Hong, J.W.;Lee, S.P.;Lee, J.U.
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.817-820
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    • 1988
  • Thermal Electet of the Zinc Oxide varistor has been studied in the temperature range of -130${\sim}200[^{\circ}C]$ and the electric field of 6[kV/m]. It appears that there are four peaks of thermally stimulated current; ${\alpha},\;{\beta},\;{\gamma}$ and ${\delta}$ spectra appearing at the temperature range of 160, 130, 20 and $-30[^{\circ}C]$, respectively. It seems that the origins of ${\alpha},\;{\beta},\;{\gamma}$ and ${\delta}$ peaks are associated with the depolarization of donor ions in the depletion layer, the detrapping of trapped electron in the surface, the detrapping of trapped electron in the donor level and the detrapping of trapped electron between grain and intergranular, respectively.

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