• 제목/요약/키워드: Self-Healing

검색결과 490건 처리시간 0.034초

Histomorphometric analysis of microcrack healing after the installation of mini-implants

  • Shin, Soobin;Park, Pan-Soo;Baek, Seung-Hak;Yang, Il-Hyung
    • Journal of Periodontal and Implant Science
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    • 제45권2호
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    • pp.62-68
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    • 2015
  • Purpose: The goal of this study was to investigate the histomorphometric characteristics of the healing process of microcracks in the cortical bone after the installation of mini-implants (MIs). Methods: Self-drilling MIs were inserted into the tibial diaphysis of twelve adult male New Zealand rabbits. Four MIs per rabbit were placed randomly. The animals were divided into four groups according to the length of the healing period: group A was sacrificed immediately, group B was sacrificed after one week, group C was sacrificed after two weeks, and group D was sacrificed after four weeks. Cortical bone thickness was measured using micro-computed tomography, and histomorphometric analyses of the cumulative length of the microcracks (CLCr) and the total number of microcracks (NCr) were performed using hematoxylin and eosin staining. Results: The microcracks were radially and concentrically aligned in the peri-MI bone. The CLCr decreased significantly one week after the surgery, mainly due to healing of the concentrically aligned microcracks. The CLCr showed another significant decrease from two weeks after the surgery to four weeks after the surgery, mainly reflecting healing of the radially aligned microcracks. A statistically significant decrease in the NCr occurred as the microcracks healed from zero weeks to two weeks. However, no significant difference in the NCr was found between groups C and D. Conclusions: In order to improve the primary stability of MIs, delayed loading and a healing period of a certain length are recommended to ensure the optimal healing of microcracks and bone remodeling.

A Comparative Study of Ayurvedic Five-element Novel and Western Element Theory (아유르베다 5원소설과 서양 원소이론 비교 고찰)

  • Choi, Jung-soon;Lee, Geo-ryong
    • Journal of Naturopathy
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    • 제10권1호
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    • pp.56-65
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    • 2021
  • Purposes: This study is to examine the causes of limitations of modern western science and philosophy through Ayurvedic thought, and to seek the path of holism for the development of national healing projects. Methods: Therefore, it was inferred that the background of modern Western civilization and the reality of the national healing project would share the flow. In order to examine this, the difference between the East and West's 'recognition of the body and the mind' and the 'perspective on the origin of existence' was examined, and the characteristics of the Ayurvedic five-element novel were examined. Results: Through that process, the "mind and body dualism" in the West and the absence of the "empty element( 空 Śunya)" in Western four-element novels were pointed out as the cause of the limitations. In the sense that the 'empty element' is an invisible world and an immaterial world, it was concluded that the absence of justice was a limitation of Western civilization and a problem of the reality of the national healing project. Conclusions: I hope that this study will lead to continuous research on Ayurvedic ideology and research in the field of natural healing, thus contributing to the development of national healing projects and leading to health, well-being, and self-healing of the people.

A Self-healing Space-Division Switch for a 2-Fiber Bidirectional Line Switched Ring (2-선 양방향 선로 스위칭 링을 위한 자기치유 공간분할 스위치 소자)

  • 이상훈;김성진
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제26권12C호
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    • pp.240-248
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    • 2001
  • This paper describes the design of a space-division switch which can support a self-healing operation of 2-fiber bidirectional line switched ring in 2.5Gb/s SDH-based transmission system. The switch having a 1.25Gb/s throughput has been designed and implemented with COMPASS tool and 0.87$\mu\textrm{m}$ CMOS gate-array. The proposed switch is suitable for the quickly self-healing operations when a failure occurs in a 2-fiber bidirectional switched ring composed of ADM transmission systems. The switch is composed of an add/drop control part, a cross-point switch, a frame-phase aligner, processor interface and an unequipped data framer. The test results of the switch adapted to 2.SGb/s SDH-based transmission system, show immediate restoration when a failure occurs.

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A Study on Self-Healing Bolted Joints using Shape Memory Alloy (형상기억합금을 이용한 자가치유 볼트접합부 시스템에 관한 연구)

  • Chang, Ha-Joo;Lee, Chang-Gil;Park, Seung-Hee
    • Journal of Korean Society of Steel Construction
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    • 제23권5호
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    • pp.629-636
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    • 2011
  • This paper describes the smart structural system that uses smart materials for real-time monitoring and active control of bolted joints in steel structures. The impedance-based structural health monitoring (SHM) techniques, which utilize the electro-mechanical coupling property of piezoelectric materials, was used to detect loose bolts in bolted joints. By monitoring the measured electrical impedance and comparing it with the measured baseline, a bolt loosening damage was detected. The damage was evaluated quantitatively using the damage metrics in conductance signature with respect to the healthy states. When loosening damage was detected in the bolted joint, the external heater actuated the shape memory alloy (SMA) washer. Then the heated SMA washer expanded axially and adjusted the bolt tension to restore the lost torque. An experiment was conducted by integrating the piezoelectric-material-based SHM function and the SMA-based active control function on a bolted joint, after which the performance of thesmart self-healing joint system was investigated.

Structural Capacity of Poles Using Crack Self-healing Concrete (균열자기치유용 콘크리트를 사용한 전주의 구조 성능)

  • Yoo, Sung-Won;Kim, Sang-Jun;Park, Hong-Gi
    • Journal of the Korean Recycled Construction Resources Institute
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    • 제6권3호
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    • pp.222-227
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    • 2018
  • Recently, due to the deterioration and various natural disasters caused by the passage of concrete pole for 20~30 years or more, damage and destruction of the poles have increased the demand for maintenance. In this paper, 10 flexural strength test specimens were fabricated by using crack self - healing concrete of Fly ash, GGBS, CA, etc. The compressive strength of the concrete with slag was found to be excellent, but the concrete with fly ash was slightly below the reference strength. In addition, the crack loadings of the specimens satisfied the criteria of KS F 4304. In the case of the load-deflection and strain relations, the behavior of the fly ash specimens was similar, but in the specimens containing the blast furnace slag, The results showed that a large amount of strain occurred.

Review on Effective Skills to Inhibit Dendrite Growth for Stable Lithium Metal Electrode (리튬금속전극의 덴드라이트 성장 억제 방안의 연구 동향)

  • Kim, Yerang;Park, Jihye;Hwang, Yujin;Jung, Cheolsoo
    • Journal of the Korean Electrochemical Society
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    • 제25권2호
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    • pp.51-68
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    • 2022
  • Although lithium metal batteries have a high energy density, experimental skills capable of solving lots of problems induced by dendrite such as short circuit, low coulomb efficiency, capacity loss, and cycle performance are still only in academic research stage. In this paper, research cases for dendrite growth inhibition on lithium metal electrode were classified into four types: flexible SEI (solid electrolyte interface) layer responding to volume expansion of lithium metal electrode, SEI supporting layer to inhibit dendrite growth physically, SHES (self-healing electrostatic shield) mechanism to adjust lithium growth by leading uniform diffusion of Li+ ions, and finally micro-patterning to induce uniform deposition of lithium. We hope to advance the practical use of lithium metal electrode by analyzing pros and cons of this classification.

A Study on the Effect of Servant Leadership on Positive Psychological Capital of Marine Police Officers (해양경찰공무원의 서번트리더십이 긍정심리자본에 미치는 영향에 관한 연구)

  • Jong-gil Kim
    • Journal of the Korean Society of Marine Environment & Safety
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    • 제29권1호
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    • pp.52-59
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    • 2023
  • The purpose of this study is to study the effect of maritime police officials' servant leadership on positive psychological capital. The subjects of the study were 167 maritime police of icials, and the results of the analysis are as follows. First, it was found that servant leadership affects positive psychological capital. Specifically, in the case of sub-variables, growth support and ethical behavior had a positive (+) effect on self-efficacy. However, community value creation and emotional healing did not affect self-ef icacy. Second, growth support and ethical behavior were found to have a positive (+) effect on optimism. However, community values and emotional healing did not affect optimism. Third, growth support, ethical behavior, and community value creation were found to have a positive (+) effect on resilience. However, emotional healing did not affect resilience. These results will serve as basic data for the human management of the maritime police.