• 제목/요약/키워드: minimal damage

검색결과 194건 처리시간 0.033초

CFRP의 자가 센싱을 이용한 패스너 손상 감지 연구 (A Study on Damage Detection of Fasteners Using Self-sensing of CFRP)

  • 이민종;이동현;이용석;권기익;왕작가;심우석;김만태;권동준
    • Composites Research
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    • 제37권4호
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    • pp.343-349
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    • 2024
  • 복합재료를 사용하여 구조물의 패스너로 활용하는 사례가 증가하고 있으며, 이러한 패스너의 피로 거동에 따른 변형을 확인하는 것이 중요하다. 본 연구에서는 복합재료 패스너로서 탄소섬유 강화 복합재료를 사용하여 클램프 형태의 패스너를 제조하고, 피로 거동 시 구조적 안정성과 전기저항 측정법을 이용한 구간별 손상률 평가를 실시하였다. 클램프형 복합재료 패스너는 평면 구간에서는 변형이 적었으나, 굴곡부에서는 피로 거동에 따라 변형이 크게 발생하였다. 각도 안정성이 부족한 경우 클램프의 손상이 굴곡부에 집중됨을 확인하였다. 동적 피로 거동에 따라 복합재료 패스너의 길이 변화율은 0.6% 이내였으나, 각도 변화율은 최대 6%까지 발생하여 굴곡부가 가장 중요하였다. 복합재료 패스너의 자체 감지 능력을 이용하여 전기저항 측정법을 통해 구간별 손상 거동을 평가하였다. 피로 거동에 따라 굴곡부의 손상이 두드러졌으며, 초기 패스너의 굴곡부가 90도 이하일 경우 큰 변형과 계면 손상이 발생함을 3D-CT 결과로 관측할 수 있었다. 이러한 결과를 바탕으로, 복합재료 패스너를 개발할 때 굴곡부의 강성 보완과 체계적인 각도 기준 제시가 중요함을 확인하였다.

Micromachining of Cr Thin Film and Glass Using an Ultrashort Pulsed Laser

  • Choi, Ji-Yeon;Kim, Jae-Gu;Shin, Bo-Sung;Whang, Kyung-Hyun
    • Journal of the Optical Society of Korea
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    • 제7권3호
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    • pp.160-164
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    • 2003
  • Materials processing by ultrashort pulsed laser is actively being applied to micromachining technology due to its advantages with regard to non-thermal machining. In this study, materials processing with ultrashort pulses was studied by using the high repetition rate of a 800 nm Ti:sapphire regenerative amplifier. This revealed that the highly precise micromachining of metallic thin film and bulk glass with a minimal heat affected zone (HAZ) could be obtained by using near damage threshold energy. Grooves with diffraction limited sub-micrometer width were obtained with widths of 620 nm on Cr thin film and 800 nm on a soda-lime glass substrate. The machined patterns were investigated through SEM images. We also phenomenologically examined the influence of variations of parameters and proposed the optimal process conditions for microfabrication.

원자력 안전문화의 정량화 방법론 개발 (Development of A New Methodology for Evaluating Nuclear Safety Culture)

  • 제무성;한기윤
    • 한국안전학회지
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    • 제30권4호
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    • pp.174-180
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    • 2015
  • This study developed a Safety Culture Impact Assessment Model (SCIAM) which consists of a safety culture assessment methodology and a safety culture impact quantification methodology. The SCIAM uses safety culture impact index (SCII) to monitor the status of safety culture of the NPPs periodically and it uses relative core damage frequency (RCDF) to present the impact of safety culture on the safety of the NPPs. As a result of applying SCIAM to the reference plant (Kori 3), the standard for the healthy safety culture of the reference plant is suggested. SCIAM might contribute to improve the safety of the NPPs (Nuclear Power Plants) by monitoring the status of safety culture periodically and presenting the standard of healthy safety culture.

하악골 골절시 사용되는 TRANSBUCCAL TROCAR TIP의 새로운 고안 (DESIGN OF TRANSBUCCAL TROCAR TIP USED IN MANDIBULAR ANGLE FRACTURES)

  • 안병근;이건주;한호진;박형태
    • Maxillofacial Plastic and Reconstructive Surgery
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    • 제11권1호
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    • pp.87-92
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    • 1989
  • Transbuccal trocar has been an established method of fixation for the bone plate in the case of mandibular angle fracture. Other than extraoral approaches, this transbuccal approach has many advantages in the treatment of the fracture of mandibular angle. These advantages are as follows ; (1) Damage to the facial nerve branches is minimal. (2) Less postoperative scar is formed. (3) Good vision of occlusion can be easily obtained on the entire operation. (4) Shorter operation time is needed. But, in the clinical procedure of plate fixation, it is has a difficulty in manipulation of the plate and correction of position. To solve these problems, we designed and used a trocar tip which can be easily attached to the trocar, and could make an improvement in the clinical procedures.

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동위원소 치료 관련 방사선 흡수선량평가 (Radiation Dosimetry for Radionuclide Therapy)

  • 김은희
    • 대한핵의학회:학술대회논문집
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    • 대한핵의학회 2001년도 제40차 춘계학술대회 및 연수교육
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    • pp.4-10
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    • 2001
  • The radionuclide therapy is a protocol for tumor control by administering radionuclides as the cytotoxic agents. Radionuclides concentrated at the site of cancerous lesion are expected to kill the cancerous cells with minimal injury to the normal tissue. The efficacy of every radionuclide treatment can be evaluated by examining the toxicity to the lesion differentiated from that to the normal tissue. Radiation dosimetry is the procedure of quantitating the energy absorbed by target volumes of interest. Dosimetric information plays an indicator of the expected radiation damage and thus the therapeutic efficacy. This paper summarizes the dosimetric aspects in radionuclide therapy in terms of radionuclides of use, radiation dosimetry methodology and considerations for each treatment in practical use.

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Complete Cord Injury after Minimal Trauma in a Patient with Forestier's Disease Accompanying Ossification of the Posterior Longitudinal Ligament

  • Oh, Gun-Seok;Ju, Chang-Il;Kim, Seok-Won;Lee, Seung-Myung;Shin, Ho
    • Journal of Korean Neurosurgical Society
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    • 제42권6호
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    • pp.487-489
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    • 2007
  • Forestier's disease is a systemic rheumatological abnormality in which exuberant ossification occurs along ligaments throughout the body, but most notably the anterior longitudinal ligament of the spine. This disease is usually asymptomatic; however dysphagia, dyspnea, and peripheral nerve entrapment have all been documented in association with the disorder. We report a rare case of catastrophic neurologic damage caused by Forestier's disease accompanying ossification of the posterior longitudinal ligament.

엑시톤 억제층 두께에 따른 유기 광기전력 소자의 특성 (Properties in Organic Photovoltaic Cell Depending on the Exciton Blocking Layer Thickness)

  • 오현석;이준웅
    • 한국전기전자재료학회논문지
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    • 제18권12호
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    • pp.1148-1151
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    • 2005
  • Photovoltaic effects in organic solar cell were studied in a cell configuration of ITO/PEDOT:PSS/CuPc(20 nm)/$C_{60}$(40 nm)/BCP/Al(150 nm) at room temperature. Here, the BCP layer works as an exciton blocking layer. The exciton blocking layer must transport electrons from the acceptor layer to the metal cathode with minimal increase in the total cell series resistance and should absorb damage during cathode deposition. Therefore, a proper thickness of the exciton blocking layer is required for an optimized photovoltaic cell. Several thicknesses of BCP were made between $C_{60}$ and Al. And we obtained characteristic parameters such as short-circuit current, open-circuit voltage, and power conversion efficiency of the device under the illumination of AM 1.5.

Neuroendoscopy : Current and Future Perspectives

  • Shim, Kyu Won;Park, Eun Kyung;Kim, Dong-Seok;Choi, Joong-Uhn
    • Journal of Korean Neurosurgical Society
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    • 제60권3호
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    • pp.322-326
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    • 2017
  • Neuroendoscopic surgery is performed because it causes minimal damage to normal structures, carries a lower rate of complications, and achieves excellent outcomes. Surgeons using an endoscope and related instruments can perform complex operations through very small incisions, which is especially useful for minimally invasive procedures for the brain and spine. Neuroendoscopic surgery is now performed in cases of obstructive hydrocephalus, various intraventricular lesions, hypothalamic hamartomas, craniosynostosis, skull base tumors, and spinal lesions. This review discusses the brief history of neuroendoscopy and the current state and future perspectives of endoscopic surgery.

BCP를 엑시톤 억제층으로 사용한 유기 광기전력 소자의 특성 (Properties of the Exciton Blocking Layer with BCP in Organic Photovoltaic cell)

  • 오현석;이준웅;이원재;김태완
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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    • pp.273-274
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    • 2005
  • Photovoltaic effects in organic solar cell were studied in a cell configuration of ITO/PEDOT:PSS/CuPc(20nm)/$C_{60}$(40nm)/BCP/Al(150nm) at room temperature. Here, the BCP layer works as an exciton blocking layer. The exciton blocking layer must transport electrons from the acceptor layer to the metal cathode with minimal increase in the total cell series resistance and should absorb damage during cathode deposition. Therefore, a proper thickness of the exciton blocking layer is required for an optimized photovoltaic cell. Several thicknesses of BCP were made between $C_{60}$ and Al. And we obtained characteristic parameters such as short-circuit current, open-circuit voltage, and power conversion efficiency of the device under the illumination of AM 1.5.

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치과시술에 사용되는 국소마취제 (Local Anesthetics for Dental Procedure)

  • 김철홍;윤지영
    • 대한치과마취과학회지
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    • 제13권3호
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    • pp.71-79
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    • 2013
  • Local pain management is the most critical aspect of patient care in dentistry. Local anesthesia is a reversible blockade of nerve conduction in an applied area that produces loss of sensation. The chemical agents used to produce local anesthesia stabilize neuronal membranes by inhibiting the ionic fluxes required for the propagation of neural impulses. Proper local anesthesia permits the dental surgeon to perform the necessary surgical procedure in a careful, gentle fashion that will be less stressful for both the operator and the patient. The improvements in agents for local anesthesia are probably the most significant advances that have occurred in dental science. Today's anesthetics are safe, effective, and can be administered with insignificant soft tissue damage and minimal concerns for allergic reactions. This article reviews the widely used local anesthetic agents for obtaining local anesthesia, and also discusses some frequently seen complications.