• Title/Summary/Keyword: Free play

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Forced vibration of an embedded single-walled carbon nanotube traversed by a moving load using nonlocal Timoshenko beam theory

  • Simsek, Mesut
    • Steel and Composite Structures
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    • v.11 no.1
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    • pp.59-76
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    • 2011
  • Dynamic analysis of an embedded single-walled carbon nanotube (SWCNT) traversed by a moving nanoparticle, which is modeled as a moving load, is investigated in this study based on the nonlocal Timoshenko beam theory, including transverse shear deformation and rotary inertia. The governing equations and boundary conditions are derived by using the principle of virtual displacement. The Galerkin method and the direct integration method of Newmark are employed to find the dynamic response of the SWCNT. A detailed parametric study is conducted to study the influences of the nonlocal parameter, aspect ratio of the SWCNT, elastic medium constant and the moving load velocity on the dynamic responses of SWCNT. For comparison purpose, free vibration frequencies of the SWCNT are obtained and compared with a previously published study. Good agreement is observed. The results show that the above mentioned effects play an important role on the dynamic behaviour of the SWCNT.

A study on the advanced mirror mold for automobile (첨단 자동차용 거울의 금형에 관한 연구)

  • 홍민성;백철승
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1999.05a
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    • pp.134-140
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    • 1999
  • The side mirrors play an important role in driver's safety and convenience. People drive safely based on the side mirrors and room mirror through observation of environment. However, the drivers can not completely confront environments because of the dead angle of the side mirrors. In this research, based on geometric optics and geometric modeling, aspheric surfaces of the side mirror mold with dead angle free has been designed and machined in CNC machining center, Surface roughness of the mold was evaluated by using surface shaping system. The analysis on the shape of formed mirrors shows the mirrors have been reduced the dead angle comparing with the original mold.

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The Principle of Facticity: Outline for a Theory of Evidence in Arbitration

  • de Barros, Octavio Fragata Martins
    • Journal of Arbitration Studies
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    • v.23 no.4
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    • pp.77-96
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    • 2013
  • International Arbitration has distinguished itself as a method for dispute resolution that pleases both common and civil law practitioners. It, however, is not free of criticism, especially when fact-finding and evidentiary issues are at play. Perhaps because fact-finding is very closely linked to the culture in which they lie, perhaps because of the lack of a clear evidentiary rules governing international arbitration, a theory of evidence in international arbitration is still far fetched. Through the analysis of the distinctions between dispute resolution systems and the search for truth paradigm, this paper aims to develop and present an outline for the development of a theory of evidence in international arbitration.

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Temperament, Parenting, and Behavioral Inhibition of Korean Toddlers (걸음마기 아동의 행동억제 : 아동의 기질 및 어머니의 양육행동과의 관계)

  • Chung, Ock Boon;Rubin, Kenneth;Park, Seong Yeon;Yoon, Chong Hee;Doh, Hyun Sim
    • Korean Journal of Child Studies
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    • v.23 no.4
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    • pp.71-88
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    • 2002
  • Mothers of 113 Korean toddlers completed Toddler Behavior Assessment Questionnaire(TBAQ) and Child Rearing Practice Report(CRPR). Observations of mother-child dyads in novel situations involving unfamiliar settings and adults assessed child's behavioral inhibition. Nonsocial inhibition were measured by the amount of time each child spent in physical contact with his/her mother in free-play episodes. Adult-social inhibition was based on child's behavior when an unfamiliar adult requested that the child approach her as she presented them with toys or activities. Results showed that TBAQ Social Fearfulness was positively associated with nonsocial and adult-social inhibition. TBAQ Pleasure was correlated negatively and TBAQ Anger Proneness positively correlated with adult-social inhibition. An interaction effect showed that child's social fearfulness and mother's overprotective behaviors affected adult-social inhibition. The regression model explained 31% of the variance.

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Relationship Between Problem Solving Ability and Emotional Stability in Preschool Children (유아기 아동의 문제해결능력과 정서적 안정과의 관계)

  • Park, Kyung Mee;Woo, Nam Hee
    • Korean Journal of Child Studies
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    • v.18 no.2
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    • pp.267-282
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    • 1997
  • The purpose of this study was to examine (1) problem solving processes, and (2) the relationship between problem solving abilities and emotional stability in preschool children. Sixty children, 4, 5, and 6 years of age were selected as subjects from 2 kindergartens. Their problem solving abilities were assessed with the Sink and Float activity and their emotional stability was measured with the House-Tree-Person test. General abilities for problem solving developed with increase in children's age. That is, age differences were found in all 3 problem solving processes of generating, testing, and applying hypotheses. No differences between sexes or kindergarten program were found. Children's emotional stability was significantly related to problem solving ability. While the relationship between emotional stability and processes of generating and applying hypotheses was not significant, emotionally stable children performed better in free play.

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Kinetics and Mechanism of the Pyridinolysis of Dimethyl Isothiocyanophosphate in Acetonitrile

  • Adhikary, Keshab Kumar;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • v.33 no.7
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    • pp.2260-2264
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    • 2012
  • The kinetics and mechanism of the pyridinolysis ($XC_5H_4N$) of dimethyl isothiocyanophosphate are investigated in acetonitrile at $55.0^{\circ}C$. The Hammett and Br$\ddot{o}$nsted plots for substituent X variations in the nucleophiles exhibit two discrete slopes with a break region between X = 3-Ac and 4-Ac. These are interpreted to indicate a mechanistic change at the break region from a concerted to a stepwise mechanism with a rate-limiting expulsion of the isothiocyanate leaving group from the intermediate. The relatively large ${\beta}x$ values imply much greater fraction of frontside nucleophilic attack TSf than that of backside attack TSb. The steric effects of the two ligands play an important role to determine the pyridinolysis rates of isothiocyanophosphates.

Characteristics of $[^3H]$-Choline Uptake into Synaptosomes from Rat Hippocampus

  • Lee, Se-Eun;Hong, Seong-Gil;Choe, Rim-Sun
    • Animal cells and systems
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    • v.2 no.2
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    • pp.233-238
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    • 1998
  • Certain basic characteristics of choline uptake in nerve terminals were studied with synaptosomes from rat hippocampus. Synaptosomal $[^3H]$-choline uptake was clarified as specific and high affinity by low Km value(2.2 uM), Na+-dependency and high sensitivity to hemicholinium-3, a competitive inhibitor of choline uptake. Choline uptake into synaptosomes was linearlys related to Na+ concentration and membrane potential. Extracellular Ca2+ modulated the choline uptake, but probably not through increase of intracellular $Ca^{2+}$, because this modulation was not affected the by high $K^+$-depolarization. EGTA (2mM) added for $Ca^{2+}$-free condition had a peculiar effect of decreasing choline uptake. These results suggest that Ca2+ may play an important role in regulating the metabolism of acetylcholine in the nerve terminals directly through the increase of acetylcholine release.

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Electromagnetic Resonant Tunneling System: Double-Magnetic Barriers

  • Kim, Nammee
    • Applied Science and Convergence Technology
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    • v.23 no.3
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    • pp.128-133
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    • 2014
  • We study the ballistic spin transport properties in a two-dimensional electron gas system in the presence of magnetic barriers using a transfer matrix method. We concentrate on the size-effect of the magnetic barriers parallel to a two-dimensional electron gas plane. We calculate the transmission probability of the ballistic spin transport in the magnetic barrier structure while varying the width of the magnetic barriers. It is shown that resonant tunneling oscillation is affected by the width and height of the magnetic barriers sensitively as well as by the inter-spacing of the barriers. We also consider the effect of additional electrostatic modulation on the top of the magnetic barriers, which could enhance the current spin polarization. Because all-semiconductor-based devices are free from the resistance mismatch problem, a resonant tunneling structure using the two-dimensional electron gas system with electric-magnetic modulation would play an important role in future spintronics applications. From the results here, we provide information on the physical parameters of a device to produce well-defined spin-polarized current.

Future Directions for Health Promotion Programs in the Public Sector (공공부문 건강증진사업의 발전방향)

  • Lee, Ju-Yul
    • Korean Journal of Health Education and Promotion
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    • v.29 no.4
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    • pp.29-38
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    • 2012
  • Objectives: This paper aims to suggest some ways we could improve the efficiency and equity in health promotion programs in the public sector. Methods: Reports published by the Minister of Health and Welfare and web-site information were reviewed. And, the empirical results and theoretical considerations provided in this study could be used in making future direction for health promotion programs in the public sector. Results and conclusion: The public sector should play a leading role in health promotion programs. The role of public sector in health promotion program is to establish the health promotion plan based on the health survey, to develop the scientific programs, to provide the free health services, and to maintain a cooperative relationship with the private sector. In order to activate the health promotion programs in the public sector, establishing the role of the public sector, changing the operation of health promotion fund, block grants for health promotion, local health promotion fund, and integration of health statistics were suggested.

Magnetopause Waves Controlling the Dynamics of Earth's Magnetosphere

  • Hwang, Kyoung-Joo
    • Journal of Astronomy and Space Sciences
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    • v.32 no.1
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    • pp.1-11
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    • 2015
  • Earth's magnetopause separating the fast and often turbulent magnetosheath and the relatively stagnant magnetosphere provides various forms of free energy that generate low-frequency surface waves. The source mechanism of this energy includes current-driven kinetic physical processes such as magnetic reconnection on the dayside magnetopause and flux transfer events drifting along the magnetopause, and velocity shear-driven (Kelvin-Helmholtz instability) or density/pressure gradient-driven (Rayleigh-Taylor instability) magnetohydro-dynamics (MHD) instabilities. The solar wind external perturbations (impulsive transient pressure pulses or quasi-periodic dynamic pressure variations) act as seed fluctuations for the magnetopause waves and trigger ULF pulsations inside the magnetosphere via global modes or mode conversion at the magnetopause. The magnetopause waves thus play an important role in the solar wind-magnetosphere coupling, which is the key to space weather. This paper presents recent findings regarding the generation of surface waves (e.g., Kelvin-Helmholtz waves) at the Earth's magnetopause and analytic and observational studies accountable for the linking of the magnetopause waves and inner magnetospheric ULF pulsations, and the impacts of magnetopause waves on the dynamics of the magnetopause and on the inner magnetosphere.