• Title/Summary/Keyword: 미분저항

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A Study on Freezing and Trawing Resistance of Concrete with the Ratio of Ground Granulated Blast-Furnace Slag Replacement (고로슬로그 미분말의 치환율에 따른 콘크리트의 동결융해 저항성에 관한 연구)

  • 최세규;김생빈
    • Magazine of the Korea Concrete Institute
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    • v.9 no.5
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    • pp.149-155
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    • 1997
  • 고로슬래그 미분말을 사용한 콘크리트\ulcorner 수화속도가 느려 어린 재령시 동해의 영향을받기 쉽다. 본 연구에서는 고로슬래그 미분말을 사용한 콘크리트의 동결융해 저항성을 알아보기 위해 고로슬래그 미분말의 치환율과 물-결합재비를 변화시켜 제조한 콘크리트에 대해 동결융해시험을 실시하였다. 또한 동일한 치환율, 물-결합재비의 콘크리트에 AE제를 첨가시켜 동결융해 저항성의 개선효과를 알아보았다. 시험결과 고로슬래그 미분말의 치환율이 증가할수록 동결융해 저항성은 작게 나왔다. 또한 non-AE 콘크리트의 경우 물-결합재비가 51%, 45%일 때 내구성지수는 각각 2.4%, 40.0%이하로 매우 나쁘게 나타났으나, AE콘크리트의 경우 물 -결합재비가 45%와 51%인 콘크리트의 내구성지수는 각각 90.2% 80.9%이상으로 동결융해 저항성이 매우 우수하게 나타났다.

Strength and Durability Properties of Concretes Using Ground Granulated Blast-Furnace Slag According to Steam Curing Types (고로(高爐)슬래그 미분말(微分末)을 사용한 콘크리트의 증기양생(蒸氣養生)에 따른 강도(强度) 및 내구특성(耐久特性))

  • Hong, Chang-Woo;Jang, Ho-Sung;Jeong, Won-Kyong
    • Resources Recycling
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    • v.15 no.4 s.72
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    • pp.52-59
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    • 2006
  • The purpose of this study was to evaluate the effects of ground granulated blast-furnace slag on strength development and durability of ordinary portland cement concrete (OPC) with steam curing types. Main experimental variables were slag contents(0%, 10%, 30%, 50%, 70%) and curing types (standard, accelerated curing). It were performed to check the basic properties of concretes that compressive strength, rapid chloride ion permeability and chemical resistance. From the result, we have found that increasing the amount of blast-furnace slag produced concrete with increased compressive strength and permeability resistance. Rapid freezing-thawing test showed that they were good enough to protect the concrete structures and to carry out cyclic freezing and thawing. The freeze-thaw resistance of blast-furnace slag produced concretes maintained above 90% of relative dynamic modulus after 300 freezing-thawing cycles. Increasing the amount of blast-furnace slag produced concretes with increased chemical resistance.

Temperature Characteristic and Writing Quality Improvement of Blu-ray Laser Diode for Optical Disc Recording (광학 디스크 기록을 위한 Blu-ray Laser Diode의 온도특성 및 기록품질 개선)

  • Lee, Do-Han;Kim, Young-Kil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.7
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    • pp.1687-1692
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    • 2010
  • In this paper, we research the method for write quality improvement by temperature characteristic of Laser diode for optical recording. Differential Resistance of Blu-ray laser diode is changed by temperature. We analyze the effect of the change of the differential resistance in low temperature and propose the method for the write quality improvement.

Compressive Strength and Resistance to Freezing and Thawing of Recycled Aggregate Concrete Containing Ground Granulated Blast Furnace Slag (고로슬래그 미분말을 혼입한 순환골재 콘크리트의 압축강도 및 동결융해 저항성)

  • Bae, Suho;Jeon, Juntai
    • Journal of the Society of Disaster Information
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    • v.9 no.4
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    • pp.469-475
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    • 2013
  • The purpose of this experimental research is to estimate compressive strength and resistance to freezing and thawing of recycled aggregate concrete containing ground granulated blast furnace slag. For this purpose, concrete specimens according to substitution ratio of recycled aggregate were made for different replacement ratio of ground granulated blast furnace slag(GGBFS), and then compressive strength and resistance to freezing and thawing were evaluated for those. It was observed from the test results that compressive strength at 28 days of recycled aggregate concrete containing GGBFS of 20% was much more excellent than plain concrete and when air content of concrete was maintained 4 to 6%, influence of substitution ratio of recycled aggregate and replacement ratio of GGBFS on resistance to freezing and thawing was little up to 300 cycles of freezing and thawing.

Study of Fundamental Properties of Latex-Modified Concrete Using Blast-furnace Slag (고로(高爐)슬래그 미분말(微粉末)을 사용(使用)한 라텍스개질(改質) 콘크리트의 기초물성(基礎物性) 연구(硏究))

  • Hong, Chang-Woo;Jeong, Won-Kyong;Kim, Kyeong-Jin
    • Resources Recycling
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    • v.15 no.2 s.70
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    • pp.10-17
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    • 2006
  • The purpose of this study was to evaluate the effects of blast-furnace slag on strength development and durability of latex-modified concrete (LMC) and ordinary portland cement concrete as slag contents. Main experimental variables were performed latex contents (0%, 10%, 15%) and slag contents (0%, 30%). The compressive and flexural strengths, chloride-ion rapid permeability and chemical attacks resistance were measured to analyze the characteristic of the developed LMC and BS-LMC(latex-modified concrete added blast-furnace slag) on hardened concrete. The test results showed that compressive and flexural strength of BS-LMC increased as the slag contents increased from 0% to 30% at the long term of curing. It considers blast furnace slag used when latex content was up to 10%. The permeability resistance of BS-LMC(latex 10%, blast 30%) was extremely good at the curing time 90 days. Also. the effects of added blast furnace slag on OPC and LMC were increased on the permeability and chemical attacks resistance.

A Study of Temperature Characteristic and Recording Quality Improvement of Blu-ray Laser Diode for Optical Media Recording (광학 디스크 기록을 위한 Blu-ray Laser Diode의 온도특성 및 기록품질 개선에 관한 연구)

  • Lee, Do-Han;Kim, Young-Kil
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.10a
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    • pp.503-505
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    • 2009
  • In this paper, we research the method for write quality improvement by temperature characteristic of Laser diode for optical recording. Differential Resistance of Blu-ray laser diode is changed by temperature. We analyze the effect of the change of the differential resistance and propose the method for the write quality improvement.

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The Microstructure and Durable Properties of the Composites with the Ground Granulated Blast Furnace Slag (고로슬래그 미분말을 사용한 몰탈의 미세구조와 내구특성)

  • Kim, Won-Ki;Soh, Jung-Sub;Kim, Dong-In;Kim, Hoon-Sang;Kim, Hong-Joo
    • Proceedings of the Korean Institute of Resources Recycling Conference
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    • 2004.05a
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    • pp.143-148
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    • 2004
  • 고로슬래그 미분말과 플라이 애쉬와 같은 재료들이 콘크리트의 내구성과 장기강도 증진을 목적으로 혼합재로서 사용되고 있다. 본 연구에서는 고로슬래그 사용 몰탈의 내구성 증진 특성을 활용하기 위하여 고로슬래그 미분말에 알칼리 자극제를 첨가한 알칼리 활성화 슬래그계 무기결합재 사용 몰탈의 내구성과 물리적 특성을 평가하였다. 실험결과, 몰탈의 초기 압축강도 발현에 알칼리 자극제가 큰 영향을 미치는 것을 확인하였다. 또한 알칼리 자극제가 첨가된 몰탈의 화학적 저항성을 평가하기 위하여 공시체를 재령 28 일 후, 5% 황산($H_2SO_4$) 용액에 침지하여 압축강도 및 질량 변화를 관찰하였다. 그 결과, 보통포틀랜드 시멘트로 제조한 몰탈의 경우, 황산용액 침지 후 압축강도가 54% 감소하였다. 반면 고로슬래그 미분말을 첨가한 몰탈의 경우, 약 10% 강도가 감소하였다. 질량변화의 경우, 보통포틀랜드 시멘트로 제조한 공시체는 17%, 고로슬래그 미분말을 첨가한 몰탈은 3%의 질량변화를 보였다. 이 결과로서 고로슬래그 미분말을 첨가한 몰탈의 경우, 화학적 저항성과 물리적 특성이 우수한 것을 확인하였다.

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Non-Contact Sensing Method using PT Symmetric Circuit with Cross-Coupled NDR Circuits (크로스-결합구조의 부성 미분 저항 회로를 이용한 페리티-시간 대칭 구조의 비접촉 센서 구동 회로에 대한 연구)

  • Hong, Jong-Kyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.4
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    • pp.10-16
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    • 2021
  • This paper proposes a model that considers the parity-time symmetric structure as a state detection circuit for sensor applications using a stretchable inductor. In particular, to obtain a more practical computer simulation result, the stretchable inductor model was applied to this study model by referring to previously reported experimental results. The resistance component and phase component were controlled through the negative differential resistance circuit used in this study. In addition, the imbalance of the circuit caused by a change in the characteristics of the stretchable inductor could be compensated for using a negative differential resistance circuit. In particular, an analysis of the frequency characteristics of the sensor driving circuit of the parity-time symmetric structure proposed in this study confirmed that the Q-factor could be increased up to 20 times compared to the conventional resonant circuit.

Evaluation of Chloride Penetration in Concrete with Ground Granulated Blast Furnace Slag considering Fineness and Replacement Ratio (고로슬래그 미분말 콘크리트의 분말도 및 치환율에 따른 염해 저항성 평가)

  • Lee, Hyun-Ho;Kwon, Seung-Jun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.1 no.1
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    • pp.26-34
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    • 2013
  • Durability performance in RC structures varies significantly with changes in cover depth and mix proportions. GGBFS (Ground Granulated Blast Furnace Slag) is very effective mineral admixture and widely used for an improved resistance to chloride attack. In this paper, characteristics such as porosity, compressive strength, and diffusion coefficient are evaluated in GGBFS concrete with 30~70% of replacement ratio and $4,000{\sim}8,000cm^2/g$ of fineness. Through the tests, more dense pore structure, higher compressive strength, and lower diffusion coefficient are obtained in GGBFS concrete, which are evaluated to be more dependent on replacement ratio than fineness. With increasing curing period from 3 to 91 days, porosity decreases to 77.47% and strength increases to 373% in GGBFS concrete. Chloride diffusion coefficient in GGBFS concrete decreases to 64.4% compared with that in OPC concrete, which shows significant improvement of durability performance.

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.