• Title/Summary/Keyword: 재접착

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Study on the Debonding Detection Techniques of Liner/Propellant Interface of Rocket Motor (추진기관의 라이너/추진제 미접착 검출 기법 연구)

  • Kim, Dong-Ryun;Ryoo, Baek-Neung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.2
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    • pp.40-47
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    • 2008
  • It is known that the adhesive interface testing of the rocket motor using the ultrasonic wave is superior to the other testing methods about the ability to economical detect the defects. But, the signal analysis of the ultrasonic wave takes a lot of time and efforts because the time interval of the transmitted pulse and the received pulse is too short to separate the reflected signals due to the multi-layers of the rocket motor. The ultrasonic testing of rocket motor have only applied to the automatic system about extremely limited areas like the debond in adhesive interface between the motor case and the insulator. In this study the new technique to detect the debond between the liner and the propellant using the property of the resonance and the lamb waves instead of the existing ultrasonic testing was described.

Study on the Debonding Detection Techniques of Liner/Propellant Interface of Rocket Motor (추진기관의 라이너/추진제 미접착 검출 기법 연구)

  • Kim, Dong-Ryun;Ryoo, Baek-Neung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.55-59
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    • 2007
  • It is known that the adhesive interface testing of the rocket motor which using the ultrasonic wave iS superior to the other testing methods about the economically detectable abiliη of the defects. But, the signal analysis of the ultrasonic wave takes too much time and effort that the time interval of the transmitted pulse and the received pulse is too short to be separated the reflected signals because the structure of the rocket motor is multi-layers. The ultrasonic testing of rocket motor have been only applied with automatic system about extremely limited area like the debond in adhesive interface between the motor case and insulator. In this study the new technique to detect the debond between the liner and the propellant using the property of the resonance and Lamb waves was described as comparing the existence ultrasonic testing.

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Comparative Analysis of Fire Resistance in Glued Laminated Timber: The Impact of Adhesives and Surface Direction (구조용 집성재의 접착제 종류 및 접착면 방향성에 따른 내화성능 비교 분석)

  • Choi, Yun-Jeong;An, Jae-Hong;Baik, Kwon-hyuk
    • Journal of the Korea Institute of Building Construction
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    • v.23 no.6
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    • pp.761-772
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    • 2023
  • The fire resistance design of timber structures involves calculating the residual section based on charring depth, which is then utilized in structural design. Charring depth is determined from fire-resistance test results in Korea, which currently do not account for the charring properties of the adhesive used in Glued Laminated Timber(GLT) production. This study fabricated GLT using various adhesives employed in domestic GLT production, comparing the charring properties by adhesive type and the fire resistance performance relative to the directionality of the laminated surface. Melamine demonstrated the most advantageous fire resistance performance, followed by resorcinol and polyurethane. Furthermore, it was established that the laminated section exhibited a higher charring rate, influenced by the adhesive, compared to the laminated surface, which significantly impacts the fire resistance performance.

Strength Properties of Polymer-Modified Repair Mortars According to Curing Conditions and Repair Methods (양생조건 및 보수방법에 따른 폴리머시멘트모르타르의 강도 성상)

  • Kim, Wan-Ki;Jo, Young-Kug
    • Journal of the Korea Concrete Institute
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    • v.19 no.4
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    • pp.457-465
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    • 2007
  • In this paper, polymer-modified repair materials using polymer dispersions with six repair methods are prepared with various polymer-cement ratios, and tested for compressive and flexural strengths through each curing condition such as dry cure, water cure, and freezing and thawing cyclic action. And, the adhesive interface between the polymer-modified mortar and mortar substrate is observed by a scanning electron microscope. From the test results, the compressive and flexural strengths of cement mortar repaired by polymer-modified mortar are improved with a rise in the polymer-cement ratio regardless of the type of polymer and curing conditions. Such an improvement in the strengths of polymer-modified repair materials to ordinary cement mortar is explained by the high adhesion of polymer-modified mortar. Strength reduction of polymer-modified repair materials after freezing and thawing cyclic actions is recognized, but it is lower than that of unmodified mortar. Especially, cement mortar repaired by polymer-modified mortar with a St/BA emulsion has good strength properties compared with those of SBR latex and PA emulsion. Accordingly, it is judged that polymer-modified mortars with a St/BA emulsion are possible to use as repair materials to ordinary cement mortar and concrete.

The Protective Effect of Prostaglandin E1 Against Ischemia-reperfusion Injury of Musculocutaneous Flaps (백서 복직근피판에 있어 허혈-재혈류 손상에 미치는 Prostaglandin E1의 예방효과)

  • Hong, Joon Pio;Chung, Yoon Kyu;Chung, Soon-Hee
    • Archives of Reconstructive Microsurgery
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    • v.9 no.2
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    • pp.190-198
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    • 2000
  • 본 연구는 백서 복직근피판에 있어 허혈-재혈류 손상에 미치는 prostaglandin E1(PGE-1)의 예방효과를 분석 실험하였으며, 그 기전으로 내피세포의 intercellular adhesion molecule-1(ICAM-1)이 down regulation 됨을 확인하였다. 기존의 PGE-1은 혈관 확장 및 혈소판 응고 저하 등의 기전으로 피판 이식술 후 주로 사용하였으나, 허혈-재혈류 손상 시에 PGE-1 역할에 대한 연구는 잘 알려진바 없다. 허혈-재혈류 손상에 대한 기전은 현재 여러 가설로 설명되고 있으나, 최근 내피 세포와 백혈구의 역할이 주목을 받고 있다. 장시간 허혈 상태의 피판은 재혈류시 백혈구가 내피세포에 접착함으로써 직간접적인 경로로 독소를 생성하며, 결국 내피세포 및 주변조직의 괴사로 이어진다. 본 연구는 면역조직학 염색을 통한 내피세포의 ICAM-1 발현 억제와 그로 인한 백혈구의 내피세포 접착 억제를 그 기전으로 볼 수 있었으며, PGE-1을 술 중 투여함으로써 피판의 생존율을 향상시킬 수 있었다.

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