• Title/Summary/Keyword: 투과깊이

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dispersion characteristics and RE power absorption for a mangetized plasma (자화 플라즈마의 분산특성과 유효광학계수 변화)

  • 라상호;정재성;오범환;박세근
    • Journal of the Korean Vacuum Society
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    • v.9 no.3
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    • pp.285-289
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    • 2000
  • It has been well known that weak axial magnetic field on the process plasma enhances plasma density. As the magnetic field helps a specific polarized EM wave mode to penetrate into the plasma, the energy transfer to the plasma enhances and the ion density increases. We have analyzed systematic change of the dispersion relation caused by the cyclotron resonance condition. This resonance occurs at near 5 gauss to provide minimum penetration depth, as known before. RF penetration depth increases abruptly beyond the magnetic field of 5 gauss, and this phenomena lessen as the collision frequency increases.

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Dimensionality Reduced Wave Transmission Function and Neural Networks for Crack Depth Estimation in Concrete Structures (차원 축소된 표면파 투과 함수와 인공신경망을 이용한 콘크리트 구조물의 균열 깊이 평가 기법)

  • Shin, Sung-Woo;Yun, Chung-Bang
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.3
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    • pp.247-253
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    • 2007
  • Determination of crack depth in filed using the self-calibrating surface wane transmission measurement and the cutting frequency in the transmission function (TRF) is very difficult due to variations of the measurement conditions. In this study, it is proposed to use the measured full TRF as a feature for crack depth assessment. A Principal component analysis (PCA) is employed to generate a basis of the measured TRFs for various crack cases. The measured TRFs are represented by their projections onto the most significant principal components. Then artificial neural networks (NNs) using the PCA-compressed TRFs is applied to assess the crack in concrete. Experimental study is carried out for five different crack cases to investigate the effectiveness of the proposed method. Results reveal that the proposed method can be effectively used for the crack depth assessment of concrete structures.

Pigment Analysis for Wall Paintings According to Verification of Penetration Depth for X-ray: Ssanggyesa Daeungjeon (Main Hall of Ssanggyesa Temple) in Nonsan (X-선 투과깊이 검증에 따른 벽화 안료의 정밀분석: 논산 쌍계사 대웅전)

  • Chun, Yu-Gun;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.27 no.3
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    • pp.269-276
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    • 2011
  • We have suggested effective P-XRF analysis method for pigment painting layer by calculating penetration depth of X-ray. This experiment calculated that X-ray generated from P-XRF was possible penetration until 1.17mm deep in the pigment painting. Based on the experimental results, analysis for eight color pigments on wall paintings in Ssanggyesa Main Hall, most pigments were painted traditional pigments. However pigments on recently restorated wall painting were used synthetic modern pigments.

Evaluation of Dosimetric Leaf Gap (DLG) at Different Depths for Dynamic IMRT (동적 세기조절방사선치료에서 깊이에 따른 DLG변화 분석)

  • Chang, Kyung Hwan;Kwak, Jungwon;Cho, Byungchul;Jeong, Chiyoung;Bae, Jae Beom;Yoon, Sang Min;Lee, Sang-wook
    • Progress in Medical Physics
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    • v.26 no.3
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    • pp.153-159
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    • 2015
  • This study is to evaluate thedosiemtric leaf gap (DLG) at different depths for dynamic intensity-modulated radiation therapy (IMRT) in order to evaluate the absolute dose and dose distribution according to the different positions of tumors and compare the measured and planned the multileaf collimator (MLC) transmission factor (T.F.) and DLG values. We used the 6 MV and 15 MV photon beam from linear accelerator with a Millenium 120 MLC system. After the import the DICOM RT files, we measured the absolute dose at different depths (2 cm, 5 cm, 10 cm, and 15 cm) to calculate the MLC T. F. and DLG. For 6 MV photon beam, the measured both MLC T. F. and DLG were increased with the increase the measured depths. When applying to treatment planning systemas fixed transmission factor with its value measured under the reference condition at depth of 5 cm, although the difference fixed and varied transmission factor is not significant, the dosiemtric effect could be presented according to the depth that the tumor is placed. Therefore, we are planning to investigate the treatment planning system whichthe T. F. and DLG factor according to at the different depths can be applied in the patient-specific treatment plan.

Evaluation of Depth Penetration by Changing Image Parameters using Phantom on Ultrasound (의료용 초음파 영상에 영향을 미치는 Algorithm Parameters 변환으로 빔 투과 깊이 연구)

  • Lee Bo Sam;Lim Hyun Soo
    • Journal of The Korean Radiological Technologist Association
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    • v.30 no.1
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    • pp.77-89
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    • 2004
  • I. 목적 : 의료용 초음파 장비의 성능 관리 중 최적 화질의 기본이 되는 심부 투과 깊이에 대해 검증이 미흡한 장비 회사의 protocol setting 값이 현재 대부분의 병원에서 사용되고 있는 실정이다. 이러한 protocol에서 벗어나 국내 여러 모델의 장치에 공통적으로 환자 검사에 실제로 사용하고 있는 algorithm 인 parameters를 사용하여 초음파 영상에 영향을 미치는 빔 투과 깊이의 변화에 따른 최적영상을 평가하고자 한다. II.

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방사선투과사진에 의한 결함깊이 및 높이의 평가

  • 심언덕;이진우;이수경;강계명
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2002.11a
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    • pp.249-256
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    • 2002
  • 구조물의 안전성 평가와 수명예측은 구조물 내 결함에 관한 정확한 정보 즉, 결함의 종류, 크기, 위치, 형상으로 평가하고 있다 이들 결함의 분석과 해석 방법으로 실시간 평가가 가능하고, 구조물에 손상을 주지 않는 비파괴 결함 평가 방법이 널리 활용되고 있다. 특히 방사선투과시험에 의한 결함 해석과 평가는 투과사진 상에 나타나는 결함의 상으로부터 결함 형상과 결함 길이는 직접 확인할 수 있으며, 결함 깊이와 결함 높이의 해석에는 입체방사선투과검사법(Stereo-radiography)과 parallax법 등으로 현재 결함 깊이와 높이를 해석하고 있으나, 이러한 방법은 결함 검출을 위하여 조사방향을 여러방향으로 하여 방사선 투과사진을 다수 촬영하여야 하고, 촬영된 결함의 분석과 해석에도 숙련된 평가 기법이 요구되는 등 많은 문제점을 내포하고 있다.(중략)

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Spectral Energy Transmission Method for Crack Depth Estimation in Concrete Structures (콘크리트 구조물의 균열 깊이 추정을 위한 스펙트럼 에너지 기법)

  • Shin, Sung-Woo;Min, Ji-Young;Yun, Chung-Bang;Popovics, John S.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.2
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    • pp.164-172
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    • 2007
  • Surface cracks in concrete are common defects that can cause significant deterioration and failure of concrete structures. Therefore, the early detection, assessment, and repair of the cracks in concrete are very important for the structural health. Among studies for crack depth assessment, self-calibrating surface wave transmission method seems to be a promising nondestructive technique, though it is still difficult in determination of the crack depth due to the variation of the experimentally obtained transmission functions. In this paper, the spectral energy transmission method is proposed for the crack depth estimation in concrete structures. To verify this method, an experimental study was carried out on a concrete slab with various surface-opening crack depths. Finally, effectiveness of the proposed method is validated by comparing the conventional time-of-flight and cutting frequency based methods. The results show an excellent potential as a practical and reliable in-situ nondestructive method for the crack depth estimation in concrete structures.

Analysis of Ground Penetration Radar Technology Trend (지중탐지 레이더 기술동향 분석)

  • Kim, D.K.
    • Electronics and Telecommunications Trends
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    • v.30 no.5
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    • pp.22-27
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    • 2015
  • 도로함몰 사고 증가를 계기로 지하 구조물의 안전 관리 방법, 특히 비파괴 검사 장비에 대한 관심이 고조되고 있다. 지중투과 레이더 기술은 전자파의 투과, 반사 특성을 이용한 비파괴 검사 기술로써 투과 깊이, 투과 해상도 등 비파괴 검사 성능 측면에서 가장 주목받고 있는 기술이다. 본고에서는 지중투과 레이더 기술의 특징, 국외 제품 동향을 살펴본다.

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Wave-blocking Efficiency of a Horizontal Porous Flexible Membrane

  • Cho, Il-Hyoung
    • Journal of Ocean Engineering and Technology
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    • v.17 no.1
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    • pp.8-15
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    • 2003
  • 본 논문에서는 투과성 유연막이 수면밑 일정한 깊이에 수평으로 잠겨있을 때 투과성 유연막에 의한 파랑제어성능을 살펴보았다. 해석 방법으로는 유체문제는 고유함수전개법 (Eigenfunction expansion method)을 사용하였고, 유연막과 파랑의 상호작용문제는 Newmann 이 제시한 유탄성 이론 (hydro-elastic theory)을 채택하였다. 막의 투과성 효과를 고려하기 위하여 수평막에서의 수직속도는 수평막 상하의 압력차에 선형적으로 비례하며 그들 사이에는 위상차가 없다고 가정한 Darcy 법칙을 사용하였다. 투과성 수평막의 설계변수 (초기장력, 길이, 잠긴 깊이, 공극율)와 입사파의 주파수를 바꿔가면서 반사율과 투과율 그리고 에너지 손실율을 살펴보았다.