• 제목/요약/키워드: The second half

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조선조대의 고차방정식의 허실

  • 유인영
    • 한국수학사학회지
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    • 제14권2호
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    • pp.1-12
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    • 2001
  • Considering the four arithmetical operations, the operations over some problems in the second half periods of Chosun Dynasty were dealt in the different dimensions were not reasonable and tile units of the dimensions were neglected. This paper aims to introduce some questionable solved problems related to tile equations higher than tile second degree.

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Half Bridge 인버터에 의한 자동차 헤드라이트용 전자식 안정기 개발 (Development of Electronic Ballast for Automotive Headlight Lamp using Half Bridge Inverter)

  • 조계현;박종연;박재일
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제52권3호
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    • pp.140-146
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    • 2003
  • In this paper, we suggested electronic ballast with the half bridge inverter for the automotive HID lamp. The electronic ballast for the automotive HID lamp should be supplied by the low-frequency square wave avoiding the acoustic resonance. When the HID lamp is hot state, the electronic ballast should supply the sufficient current to the take over to the lamp at the re-strike ignition state for a few milli-second. We have introduced the new take-over current control method that could have control operating frequency and minimize circuits to the take over current circuits.

낙동강 본류에 분포하는 표층 퇴적물의 지화학적 특성 변화 (Change in Geochemical Characteristics of Surface Sediments in the Nakdong River Main Stream)

  • 김신;이권철;김주언;정강영;안정민;김형근;이인정;신동석;양득석
    • 한국환경과학회지
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    • 제26권3호
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    • pp.311-324
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    • 2017
  • To certificate change in the geochemical characteristics of surface sediments in the main stream of the Nakdong River, surface sediments from 12 sampling sites during the first and second half year (total 24 sampling sites) were collected and analyzed for grain size, ignition loss, total organic carbon and heavy metal content. Surface sediments mainly composed of sand (coarse and medium sand) and fining changed from the first half to the second half of the year. Ignition loss, total organic carbon and heavy metals content increased in the second half of the year. Some heavy metals (Zn, Ni and Cu) were found to be at the lowest effect levels according to Ontario sediment quality guidelines. Additionally, most heavy metals were found to be at the non polluted level and level I according to USEPA sediment quality standards and National Institute of Environmental Research sediment pollution evaluation standard, respectively. The enrichment factor (< 1) and index of geoaccmulation (< 0) were non polluted in the study area. The correlation analysis results showed that ignition loss, total organic carbon and heavy metal content were highly correlated with grain size. Regarding changes in geochemical characteristics of surface sediments in the study area, grain size fine and organic matter and heavy metal content increased in the second half year. Nonetheless these results indicated pollution levels that did not adversely affect the benthos.

직교이방성 층과 반무한체 사이의 계면균열에 대한 좌굴 (Buckling for an Interface Crack Between an Orthotropic Layer and a Half-Space)

  • 정경문;범현규
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.815-818
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    • 2001
  • The buckling of an orthotropic layer bonded to an isotropic half-space with an interface crack subjected to compressive load under plane strain is considered. Basic stability equations derived from the mathematical theory of elasticity are applied to describe the buckling behavior. A system of homogeneous Cauchy-type singular integral equations of the second kind is solved numerically by utilizing Gauss-Chebyshev integral formulae. Numerical results for the buckling load are presented for various delamination geometries and material properties of both the layer and half-space.

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윤동주의 시 "별헤는 밤"의 비유구조 (The Figurative Structure of 'One Night, Counting the Stars")

  • 유재천
    • 인문언어
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    • 제1권1호
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    • pp.185-194
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    • 2001
  • In this paper, I propose that the figurative structure of Tongjoo Yoon′s "One Night, Counting the Stars" reflects the poet′s anguish over the colonial reality of Korea in the later stages of the Japanese occupation, especially regarding the forced adoption of Japanese names in 1939. The poet Yoon himself registered at Yonhi College with an adopted Japanese name. In the second half of the poem, the speaker alludes to this historical fact when he confesses that "On a hill lit by myriads of stars / I spelled my name / And covered it over with dirt," and that he "laments (his) shameful name." In the simile of the last stanza, the speaker continues to allude to the "buried" name: "But past winter, come spring to my star, / As green grass sprouts on a grave mound, / So will it spread with pride / On the hill where my name is buried." The longing and the yearning, expressed so simply and in child-like manner in the first half of the poem, become in the second half an urgent need for something that should have been but cannot be, and yet will be in the future-for a world that should be, now lost but to be regained. The poem contains the poet′s earnest belief that the inherited Korean names that were then so shamefully taken away will one day be recovered. It is almost impossible to find any other work written in Korean (despite the most suppressive measures against the use of the Korean language) that also alludes to the adoption of Japanese names. In this respect, "One Night, Counting the Stars" has a unique value in the history of modem Korean literature.

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"유네스코 지속가능발전교육 세계회의"의 성과와 시사점 (Outcomes and Implications of UNESCO ESD World Conference)

  • 이선경;강상규
    • 한국환경교육학회지:환경교육
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    • 제22권3호
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    • pp.1-14
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    • 2009
  • The UNESCO World Conference on "Education for Sustainable Development - Moving into the Second Half of the United Nations Decade" was held in Bonn, Germany, from 31 March to 2 April 2009, as the DESD approaches it's mid-point. It brought 900 participants including 47 ministers and deputy-ministers of education from 147 countries. The objectives of the conference were to: (1) highlight the essential contribution of Education for Sustainable Development (ESD) to all of education and to achieving quality education ("Why is ESD relevant?"); (2) promote international exchange on ESD ("What can we learn from each other?"); (3) carry out a stock-taking of DESD implementation ("What have we achieved so far, what are the lessons learnt?"); (4) develop strategies for the way ahead ("Where do we want to go from here ?"). The conference provided opportunities for all participants to recognize the importance of ESD as the way to meet challenges of the present unsustainable world and discuss outcomes of first-half of DESD and action plans for second-half of DESD. In particular, one plenary session was focused on the DESD Monitoring and Evaluation process, with a presentation of the key findings of the draft global report on the context and structures of ESD, as well as regional perspectives. As a result of the conference, participants adopted the Bonn Declaration which would serve as the backbone for the further development of the post-Bonn process within the framework of the DESD.

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ON THE INVERSE PROBLEM FOR STURM-LIOUVILLE OPERATOR WITH A NONLINEAR SPECTRAL PARAMETER IN THE BOUNDARY CONDITION

  • Mamedov, Khanlar R.
    • 대한수학회지
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    • 제46권6호
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    • pp.1243-1254
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    • 2009
  • The inverse scattering problem is investigated for some second order differential equation with a nonlinear spectral parameter in the boundary condition on the half line [0, $\infty$). In the present paper the coefficient of spectral parameter is not a pure imaginary number and the boundary value problem is not selfadjoint. We define the scattering data of the problem, derive the main integral equation and show that the potential is uniquely recovered.

코팅부 균열의 충격특성 해석 (An Analysis on the Impact Characteristics in a Layered Half-Space with a Cathing Region)

  • 이강요;권순만
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1995년도 추계학술대회 논문집
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    • pp.664-667
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    • 1995
  • The purpose of this paper is to consider the disk failure phenomenon based on the second kind Fredholm integral equation and numerical inversion of Laplace transform when the head hit disk asperities at HDI under antiplane impact loading. The model for analysis is a two layeered half-space with a circumferential surface edge crack. The optimum design parameters to reduce the disk failure due to impact are presented

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Birefringence measurements of lmol%Mg:LiNbO3 with Noncollinea­rphase­matching cone

  • Lee, Jong-Soo;Rhee, Bum-Ku;Joo, Gi-Tae
    • Journal of the Optical Society of Korea
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    • 제2권2호
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    • pp.54-57
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    • 1998
  • A noncollinear-phase-matching cone of second harmonic generation(SHG) was observed in a LiNbO3 crystal doped with l mol% MgO. Birefringence refractive indices can be accurately evaluated by analysing the temperature phase matching characteristic for SHG combined with the measurement of the half cone angle. The electro-optic coefficient can also be determined form the observed change of the half cone angle when a DC electric field is applied along the optic axis.