• 한국초등과학교육학회지:초등과학교육
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• 제33권2호
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• pp.273-285
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• 2014

Purpose of this study is to analyze eye movements of pre-service teachers and elementary students about a visual material of the change on the lunar phases. Eye-Tracker was used for analysis for eye-fixation time and eye movement at the structure, behavior, function question on the visual material. The Results were as follows. First, the pre-service teacher checked the visual materials from a holistic perspective depending on the function questions and fixed eye-fixation on the moon of the behavior question concerned. On the contrary, elementary school student only checked function of the moon located in the upper part and eye-fixation focus was spread here and there regardless of the questions. Second, the pre-service teacher gazed at the sun, earth and moon in a consecutive order depending on the questions to identify their spatial relations and checked location of the moon related to the question. On the contrary, the elementary school student did not view relations between earth, sun and moon from a spatial perspective. These findings indicate that the pre-service teacher conjures up the mechanism of the change on the lunar phases and confirms it in visual materials by visualizing change on the lunar phase model from earth's point of view while the elementary school student fails to take advantage of visual materials to visualize it from earth's point of view.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.216-218
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• 2003

The Judd-Ofelt theory is becoming basis that induced of ligand field of electric dipole transitions of between 4f electic states. It is developed for the rare earth ions through judd and of ofelt. This theory be applicate success to the raer earth ions in solid, liquid and gas state. This paper reports a optical characteristices of Nd:glass by using the Judd-Ofelt Method.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.651-658
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• 2002

A series of experimental study are performed to evaluate the shear strength and friction properties of fiber-mixed soil as backfill material in reinforced earth wall. In order to evaluate the properties of shear strength the big-size direct shear tests are carried out and on the friction properties, the shear friction tests and the pull-out tests are performed. In the results, when the mixed ratio of the net type fiber is 0.2%, the reinforcement effect was better than the others. Also the reinforcement effect of the net type fiber was larger than that of the line type fiber.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.93-96
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• 2000

In this study, we investigated the electromagnetic properties of Mn-Zn ferrite doped with rare earth oxide (Dy$_2$O$_3$, Er$_2$O$_3$). The main composition is 52mo1% ${\alpha}$-Fe$_2$O$_3$, 25mol% Mn$_3$O$_4$ 23mo1% ZnO and doped with them(0.05wt% ∼ 0.25wt%, step:0.05wt%). An experimental process has advanced by conventional ferrimagnetism manufacturing that was prepared by standard ceramic techniques. The XRD pattern of all doped sample were observed spinel and secondary phase. The density of sample were measured nearly constant value. As increased the additive, resistivity, initial permeability and real component of the series complex permeability increased with setting limits each other. In case of Mn-Zn ferrite excess doped with them, resistivity, initial permeability and real component of the series complex permeability decreased and magnetic loss increased in proportion to increasing the additive.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.478-479
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• 2007

Many electrical fires are occurred by leakage currents and sparks generated by a short circuit. Earth leakage circuit breakers (ELCBs) should be tripped at the moment of the faults mentioned above. In this paper, we described the tripping characteristics of ELCBs against parallel arcing faults. A diesel engine generator with the capacity of 375 kVA source was adopted to provide enough large current when a parallel arcing occurred. The experimental results showed that most ELCBs we experimented were not tripped against short-duration pulse currents produced by parallel arcing because the ELCBs are designed to be tripped by a large current with long duration similar to power frequency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.37-40
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• 2002

Ground connection began by experimenting lightning with the use of a kite and it means electric appliances, communication equipments, measuring instruments and so on connecting the Earth in order to flow away overcharged electricity. There are two kinds of earth connection: Power Ground and Signal Ground. Power Ground is for preventing an electric shock and in general there's no current in the connector. However in an accident, there's a quick flow of electricity out to the Earth. Signal Ground is not only for the safety of appliances but also for the safety of equipment operation. This paper is about connection for noise and interference reduce in order to prevent wrong operation and distortion of signal in the electrical appliances which can take place in cable TV.

• 한국화예디자인학연구
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• 제42호
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• pp.37-62
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• 2020

흙은 그 자체로 자연치유력을 가진 동시에 친환경적이며, 정서적, 심리적인 안정감을 주는 천연 재료이다. 이 논문에서는 치유공간으로서의 기능을 확대하기 위한 방안의 하나로 한의원인테리어의 건축에 흙의 효과성을 적극적으로 활용한 설계와 시공방식을 구체화하였다. 특히 바이오필릭(Biopillic) 디자인 개념을 치유환경 디자인으로 활용하여 자연을 상징하는 색채, 빛, 식물, 꽃, 자연재료인 흙, 목재 등을 치유공간인 한의원인테리어로 연출하였다. 이 가운데 환자들의 동선에 따른 공간을 구획하고 공간별 특성에 따른 흙건축 공법을 적용하였다. 이때 흙은 첨가재를 넣지 않은 친환경 건축자재 인증등급 HB(Healthy Building)의 최우수 등급에 준하는 재료와 마감재인 흙으로 시공하여 인테리어와 치료개념을 동시에 연출가능 하도록 하였다. 본 연구결과는 향후 치유공간을 구성하는 데 바이오필릭((Biophilic) 디자인을 활용한 치유공간요소의 대입으로 시공의 설계와 흙건축 공법의 활용에 필요한 토대로 작용할 수 있을 것이다. 또한, 미래지향적 대안으로 건축디자인에 흙의 활용 영역을 확장시킬 수 계기가 될 수 있을 것이다.

• 한국지구과학회지
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• 제38권6호
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• pp.427-441
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• 2017

Theory of Earth's free oscillation is revisited. Firstly, we summarized the underlying formulations, such as the equation of motion and its conversion into numerically integrable form and then explained computational procedures including the treatment of inner core-outer core boundary and core-mantle boundary, while the latter information has not been explicitly given in most publications. Secondly, we re-calculated the periods of Earth's free oscillation modes (period >200 s) for PREM model. In doing so we acquired the values of modes missing in Dziewonski and Anderson (1981). As a case observation, one seismogram after 2011 Tohoku earthquake recorded at Daejeon, Korea (KIGAM seismic station) was briefly analyzed to identify free oscillation mode excitations on its spectra. The material in this article will be most clear guide for those on calculating the Earth's free oscillation mode.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.411-418
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• 2001

The last 30 years have been significant worldwide growth in the use of EPS as a lightweight fill material. This paper analyzes the compressible inclusion function of EPS which can results in reduction of static earth pressure by accomodating the movement of retained soil. A series of model tests was conducted to evaluate the reduction of static earth pressure using EPS inclusion and determine the optimum stiffness of EPS, Also, field test was conducted to evaluate the reduction of static earth pressure using EPS inclusion. Based on field test it is found that the magnitude of static earth pressure was reduced about 20% compared with theoretical active earth pressure.

• 한국지반공학회논문집
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• 제20권1호
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• pp.101-108
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• 2004

최근 30년간 EPS 블록은 전 세계적으로 그 사용량이 증가하고 있으며, 국내$.$외적으로 EPS 블록의 적용 분야가 확장되고 있는 추세에 있다. 그 대표적인 사례로 EPS 블록의 압축성에 따른 아칭효과를 이용한 옹벽, 교대, 매설관등 지반구조물에 작용하는 토압 저감 분야를 들 수 있다. EPS 블록은 경량성에 기인한 우수한 시공성과 밀도 변화에 따른 균질한 공학적 특성을 가지고 있으며, 또한 압축재로서 최적의 재료적 특성을 갖추고 있다. 일반적으로 EPS 블록은 밀도가 낮은 경우 동일한 하중 아래에서 보다 압축성이 우수한 경향을 보이나, 밀도가 10kg/$\textrm{m}^3$ 이하인 경우 발포 비드간 결합력이 약하여 쉽게 파괴되는 성질이 있으므로 지반공학적으로 이용할 때에는 10kg/$\textrm{m}^3$ 이상의 제품을 이용하는 것이 바람직한 것으로 알려져 있다. 본 연구에서는 지반구조물의 하중 저감을 위한 아칭재로서의 EPS 블록의 현장 적용성 평가를 위하여 콘크리트 옹벽과 콘크리트 박스 암거를 대상으로 현장시험시공을 수행하였으며, 현장시험시공 결과 아칭재인 EPS 블록을 사용할 경우 기존의 이론적인 토압에 비하여 콘크리트 옹벽의 경우 약 20% 정도, 콘크리트 박스 암거의 경우 약 45∼53% 정도인 것으로 평가되었다.