• Title/Summary/Keyword: 미분체

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Study on the Characteristic of Non Cement Matrix using Blast Furnace Slag (고로슬래그를 사용한 무시멘트 경화체의 특성 연구)

  • Park, Sun-Gyu
    • Proceedings of the Korea Contents Association Conference
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    • 2013.05a
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    • pp.101-102
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    • 2013
  • 시멘트 및 건설산업은 그 제조과정에서 다량의 이산화탄소를 배출하기 때문에 지구온난화 문제를 가속화시키고 있는 것으로 알려져 있다. 따라서 이러한 시멘트를 대체할 수 있는 재료 개발에 많은 연구가 이루어지고 있으며, 철강산업 부산물인 고로슬래그 미분말은 그 중 하나의 재료라 할 수 있다. 고로슬래그 미분말은 물과 직접 반응하지 않으나 알칼리 환경하에서는 물과 반응하여 CSH 수화물을 생성하게 된다. 본 연구에서는 알칼리 자극제를 첨가한 경우의 무시멘트 경화체에 대한 강도 및 수화 특성에 대하여 분석하고자 하였다.

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Survey on electrocoagulation to purify contaminated water (전기응고법을 이용한 오염 수 정화)

  • Kim, W.Y.;Park, K.S.;Oh, C.S.
    • Journal of Energy Engineering
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    • v.23 no.3
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    • pp.17-20
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    • 2014
  • A magnetic fluid separation technology was confirmed to be very effective to remove the suspended solids from contaminated water. We have surveyed on the effects of operating variables on the characteristics of suspended solids(SS) removal investigated through the test runs using magnetic powder. Magnetic flocculation here formed by adsorbing fine magnetites on the surface of suspended solid was observed. The strength of magnet was of significance in determining the SS removal efficiency.

Self-Diagnosis Property of Fracture in Carbon Fiber Composite Mortar (탄소섬유 분말 혼입 모르타르 복합 구조체의 파괴예측 자가진단 특성)

  • Park, Seok-Kyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.1
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    • pp.113-120
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    • 2007
  • A new material was tested and its applicability was investigated so as to give the capability of self-diagnosis of fracture in composite mortar. In the research for giving self-diagnosis capability, conductive mortar intermixed with cokes and carbon fiber powder(milled carbon fiber) was developed and its using for self-diagnosis material was proposed. Then after examining change in the value of electric resistance and AE characteristics before and after the occurrence of cracks at each weight-stage, the relationships of each factors were analyzed. As the results, it can be recognized that a new composite material with cokes and carbon fiber powder(milled carbon fiber) can be applied for self-diagnosis of fracture in mortar specimen.

Closed-form Expressions of Magnetic Field and Magnetic Gradient Tensor due to a Circular Disk (원판형 이상체에 의한 자력 및 자력 변화율 텐서 반응식)

  • Rim, Hyoungrea
    • Geophysics and Geophysical Exploration
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    • v.25 no.1
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    • pp.38-43
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    • 2022
  • In case axial symmetrical bodies with varying cross sections such as volcanic conduits and unexploded ordnance (UXO), it is efficient to approximate them by adding the response of thin disks perpendicular to the axis of symmetry. To compute the vector magnetic and magnetic gradient tensor respones by such bodies, it is necessary to derive an analytical expression of the circular disk. Therefore, in this study, we drive closed-form expressions of the vector magnetic and magnetic gradient tensor due to a circular disk. First, the vector magnetic field is obtained from the existing gravity gradient tensor using Poisson's relation where the gravity gradient tensor due to the same disk with a constant density can be transformed into a magnetic field. Then, the magnetic gradient tensor is derived by differentiating the vector magnetic field with respect to the cylindrical coordinates converted from the Cartesian coordinate system. Finally, both the vector magnetic and magnetic gradient tensors are derived using Lipschitz-Hankel type integrals based on the axial symmetry of the circular disk.

Closed-form Expressions of Vector Gravity and Gravity Gradient Tensor due to a Line Segment (선형 이상체에 의한 중력 및 중력 변화율 텐서 반응식)

  • Rim, Hyoungrea
    • Geophysics and Geophysical Exploration
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    • v.25 no.1
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    • pp.44-49
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    • 2022
  • Closed-form expressions of vector gravity and gravity gradient tensor based on a line segment are derived. If a cylindrical object with axial symmetry is observed from a distance, it is possible to approximate it as a line segment; therefore, it is necessary to compute the gravity and the gravity gradient tensor due to a line source by using closed-form expressions. The gravitational potential for a line segment is defined as a one-dimensional integral, and this integral is differentiated with respect to the Cartesian coordinate system to derive the vector gravity. The expressions of the gravity gradient tensor are derived by differentiating the vector gravity once more in the same coordinate system.

Effects of Glass Particle Size on the Electrical Properties of Thick Film Resistors (후막저항체의 전기적 특성에 미치는 유리입자 크기의 영향)

  • 허행진
    • Journal of the Microelectronics and Packaging Society
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    • v.1 no.1
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    • pp.51-60
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    • 1994
  • RuO2 계 후막저항체에 사용된 유리의 입도 및 연화점이 후막저항체의 전기적 특성 에 미치는 영향을 시험하기 위하여 연화점이 서로 다른 두 종류의 유리를 제조하고 이들을 미분쇄하여 각각 세 조류의 평균입도로 분급하였다. 이 유리분말들을 이용하여 여섯 종류의 후막저항체를 제조하고 그 저항체들의 전기적 특성을 평가하고 고찰하였다. 연화점이 높은 유리로 만든 후막저항체들보다 높은 쉬트 저항을 나타냈다. 또한 후막저항체들의 쉬트 저항 및 저항온도계수는 저항체들의 미세조직과 밀접한 관계가 있음을 확인하였다.