• 제목/요약/키워드: In-situ characterization

검색결과 252건 처리시간 0.024초

Nondestructive Characterization and In-situ Monitoring of Corrosion Degradation by Backward Radiated Ultrasound

  • Song, Sung-Jin;Kim, Young H.;Bae, Dong-Ho;Kwon, Sung D.
    • Corrosion Science and Technology
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    • 제4권3호
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    • pp.114-119
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    • 2005
  • Since the degradation caused by corrosion is restricted to the surface of materials, conventional ultrasonic nondestructive evaluation methods based on ultrasonic bulk waves are not applicable to characterization of the corrosion degradation. To take care of this difficulty, a new nondestructive evaluation method that uses ultrasonic backward radiation has been proposed recently. This paper explores the potential of this newly developed method for nondestructive characterization and in-situ monitoring of corrosion degradation. Specifically, backward radiated ultrasounds from aged thermo-mechanically controlled process (TMCP) steel specimens by corrosion fatigue were measured and their characteristics were correlated to those of the aged specimens. The excellent correlation observed in the present study demonstrates the high potential of the backward radiated ultrasound as an effective tool for nondestructive characterization of corrosion degradation. In addition, the potential of the backward radiated ultrasound to in-situ monitoring of corrosion degradation is under current investigation.

Engineering characterization of intermediate geomaterials - A review

  • T. Ashok Kumar;Ramanandan Saseendran;V. Sundaravel
    • Geomechanics and Engineering
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    • 제33권5호
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    • pp.453-462
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    • 2023
  • Intermediate Geomaterials (IGMs) are natural formation materials that exhibit the engineering behavior (strength and compressibility) between soils and rocks. The engineering behavior of such material is highly unpredictable as the IGMs are stiffer than soils and weaker/softer than rocks. Further, the characterization of such material needs exposure to both soil and rock mechanics. In most conventional designs of geotechnical structures, the engineering properties of the IGMs are either aligned with soils or rocks, and this assumption may end up either in an over-conservative design or under-conservative design. Hence, many researchers have attempted to evaluate its actual engineering properties through laboratory tests. However, the test results are partially reliable due to the poor core recovery of IGMs and the possible sample disturbance. Subsequently, in-situ tests have been used in recent years to evaluate the engineering properties of IGMs. However, the respective in-situ test finds its limitations while exploring IGMs with different geological formations at deeper depths with the constraints of sampling. Standard Penetration Test (SPT) is the strength-based index test that is often used to explore IGMs. Moreover, it was also observed that the coefficient of variation of the design parameters (which represents the uncertainties in the design parameters) of IGMs is relatively high, and also the studies on the probabilistic characterization of IGMs are limited compared with soils and rocks. With this perspective, the present article reviews the laboratory and in-situ tests used to characterize the IGMs and explores the shear strength variation based on their geological origin.

State-of-the-art and challenges of non-destructive techniques for in-situ radiological characterization of nuclear facilities to be dismantled

  • Amgarou, Khalil;Herranz, Margarita
    • Nuclear Engineering and Technology
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    • 제53권11호
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    • pp.3491-3504
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    • 2021
  • This paper reports on the state-of-the-art of the main non-destructive assay (NDA) techniques usually used for in-situ radiological characterization of nuclear facilities subject to a decommissioning programme. For the sake of clarity and coherence, they have been classified as environmental radiation monitoring, surface contamination measurements, gamma spectrometry, passive neutron counting and radiation cameras. Particular mention is also made here to the various challenges that each of these techniques must currently overcome, together with the formulation of some proposals for a potential evolution in the future.

방사광 X-선을 이용한 리튬이온전지 소재의 실시간 구조 분석 연구 (In situ Synchrotron X-ray Techniques for Structural Investigation of Electrode Materials for Li-ion Battery)

  • 한다슬;남경완
    • 세라미스트
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    • 제22권4호
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    • pp.402-416
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    • 2019
  • The development of next-generation secondary batteries, including lithium-ion batteries (LIB), requires performance enhancements such as high energy/high power density, low cost, long life, and excellent safety. The discovery of new materials with such requirements is a challenging and time-consuming process with great difficulty. To pursue this challenging endeavor, it is pivotal to understand the structure and interface of electrode materials in a multiscale level at the atomic, molecular, macro-scale during charging / discharging. In this regard, various advanced material characterization tools, including the first-principle calculation, high-resolution electron microscopy, and synchrotron-based X-ray techniques, have been actively employed to understand the charge storage- and degradation-mechanisms of various electrode materials. In this article, we introduce and review recent advances in in-situ synchrotron-based x-ray techniques to study electrode materials for LIBs during thermal degradation and charging/discharging. We show that the fundamental understanding of the structure and interface of the battery materials gained through these advanced in-situ investigations provides valuable insight into designing next-generation electrode materials with significantly improved performance in terms of high energy/high power density, low cost, long life, and excellent safety.

고효율 장수명의 Flexible OLED 디스플레이를 위한 in-situ Passivation System 개발 (Development of in-situ Passivation System for High Efficiency and Long Lifetime of Flexible OLED Display)

  • 김관도
    • 전기전자학회논문지
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    • 제21권1호
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    • pp.85-88
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    • 2017
  • 본 연구에서는 OLED 소자 및 패시베이션 박막을 하나의 시스템에서 동시에 제작하여 진행할 수 있는 in-situ passivation 클러스터 시스템을 개발하고 이러한 시스템을 이용하여 OLED 디스플레이 제작 및 특성을 연구함으로써 플렉시블 디스플레이에 적용할 수 있는 기술을 구현하였다. In-situ passivation을 이용한 OLED의 제작 및 특성 분석에 관하여 연구하여 다음과 같은 결과를 얻었다. 첫째, In-situ 시스템으로 OLED 소자 제작 및 박막 패시베이션 가능한 시스템을 자체적으로 구축하였으며, 패시베이션 박막을 제작하여 그 특성을 평가한 결과 본 시스템의 응용 가능성을 제시할 수 있었다. 둘째, $SiO_2$, SiNx 무기 박막을 PECVD 방법으로 제작하여 OLED 패시베이션 박막으로 적용 가능성을 확인하였다. 본 연구결과, in-situ passivation 시스템의 적용 가능성을 확인할 수 있었고, 플렉시블 디스플레이에 적합한 패시베이션 방법으로서의 구현 가능성을 제시하였다.