• Current Optics and Photonics
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• 제4권1호
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• pp.31-43
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• 2020

The feasibility of the application of terahertz electromagnetic waves in the diagnosis of prostate cancer was examined. Four samples of incomplete cancerous prostatic paraffin-embedded tissues were examined using terahertz spectral imaging (TPI) system and the results obtained by comparing the absorption coefficient and refractive index of prostate tumor, normal prostate tissue and smooth muscle from one of the paraffin tissue masses examined were reported. Three hundred and sixty cases of absorption coefficients from one of the paraffin tissues examined were used as raw data to classify these three tissues using the Principal Component Analysis (PCA) and Least Squares Support Vector Machine (LS-SVM). An excellent classification with an accuracy of 92.22% in the prediction set was achieved. Using the distribution information of THz reflection signal intensity from sample surface and absorption coefficient of the sample, an attempt was made to use the TPI system to identify the boundaries of the different tissues involved (prostate tumors, normal and smooth muscles). The location of three identified regions in the terahertz images (frequency domain slice absorption coefficient imaging, 1.2 THz) were compared with those obtained from the histopathologic examination. The tissue tumor region had a distinctively visible color and could well be distinguished from other tissue regions in terahertz images. Results indicate that a THz spectroscopy imaging system can be efficiently used in conjunction with the proposed advanced computer-based mathematical analysis method to identify tumor regions in the paraffin tissue mass of prostate cancer.

• 비파괴검사학회지
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• 제24권5호
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• pp.525-531
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• 2004

본 고는 적외선 열화상의 개념과 적외선열화상 측정윈리 및 카메라 셋팅을 기술하고 적외선열화강(IRT)에 의한 비파괴검사(NDT)의 활용 및 비파괴검사의 진단에 대하여 살펴보았다. 적외선 열화상은 주어진 표면을 따라 온도에 관련된 열패턴의 평가를 통한 정기적인 비접촉, 비파괴 시험의 수행으로 초기에 장비 고장의 예방이 가능하다. 진단 활용으로서, 열적으로 가열된 내부결함이 있는 블록에 대하여 적외선열화상을 이용한 열화상 패턴을 비파괴 기법으로 평가하고, 결함과 열화상패턴간의 특성을 분석하여 열화상 평가 기법에 대하여 논하였다.

• 한국터널지하공간학회 논문집
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• 제3권1호
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• pp.37-50
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• 2001

최근 터널구조물에서 결함이나 변상이 많이 발생하고 있지만 터널구조물의 특수성으로 인하여 그 원인을 평가하거나, 상태 및 안전성 평가에 있어 많은 어려움을 겪고 있다. 따라서 보다 효율적인 안전진단 및 유지관리대책이 요구되고 있다. 본 연구에서는 터널에서의 정밀안전진단을 효과적으로 수행하기 위하여 터널 라이닝과 주변지반에 대한 비파괴 조사기술, 터널 라이닝의 구조적 안정성을 평가할 수 있는 해석기술, 그리고 터널의 변상원인 및 건전도를 판단할 수 있는 평가기술을 개발하여 터널의 열화 및 손상정도를 진단하고 터널의 유지관리를 위한 적절한 보수 보강대책을 제시함으로서 체계적인 터널 안전진단업무에 활용하도록 하였다.

• 한국수산과학회지
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• 제51권1호
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• pp.23-30
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• 2018

Kudoa septempunctata, a myxosporean parasite that infects olive flounder Paralichthys olivaceus is known to cause Kudoa food poisoning. Entire trunk muscle (ETM) is used for diagnosis of the parasite in fish and this method demands sacrifice of the host, causing a loss of commercial value. We developed a non-destructive method that uses a plastic syringe-style implanter to draw the sample, called the part-point muscle (PPM) sampling technique. We validated the PPM method in fish infected with K. septempunctata at the level detectable by the ETM method. We confirmed that the PPM method is equally sensitive in comparison to the ETM method for diagnosing K. septempunctata spores in olive flounder muscle. Our study also confirmed that the parasite is uniformly distributed in the dorsal muscle of infected fish. Over a period of 1 month, we observed no mortality of the host fish used for sampling by the PPM method. Thus, our studies demonstrate that the PPM sampling technique is an efficient, non-destructive method for diagnosing K. septempunctata in olive flounder.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 제2회 학술대회 논문집 일렉트렛트 및 응용기술전문연구회
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• pp.36-39
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• 2000

This paper presents the technology of condition diagnosis & life estimation on insulation system of the traction motor. In the non-destructive methods for diagnosis of coil insulation state, residual dielectric strength is estimated by the D-map which consist of the partial discharge quantity Q and average degradation degree $\Delta$. In the operating history of machine, the N-Y life estimation method is based on the stop-starting numbers and operating times with considering each degradation factor by the thermal, electrical and heat-cycle stress. With the on-line conditioning monitoring on the currents of traction motors, detecting the abnormal operating state due to bearing faults, stator or armature faults, eccentricity related faults and broken rotor bars can be performed.

• 한국구조물진단유지관리공학회 논문집
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• 제19권4호
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• pp.25-34
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• 2015

정밀안전진단시 콘크리트 강도를 추정하기 위한 방법으로 강도추정식을 이용한 방법이 많이 사용되며, 이용되는 추정식은 외국에서 이미 제안된 식이 대부분이고, 적용되는 추정식에 따라서 추정강도의 차이가 심하게 발생하며, 전반적으로 강도추정의 신뢰도가 낮아져 정밀 안전진단 결과의 신뢰성에도 상당한 영향을 미친다. 이런 문제점은 일부 국한된 부분에서 발생하게 되어 다수의 실험을 통하여 신뢰도를 높일 수 있다. 본 논문은 이와 같은 필요성을 포괄하기 위해 실내압축강도와 관련된 신뢰도 평가식을 제안하였다. 확률론적 기법을 이용하여 신뢰도 평가식의 유용성을 검증하였으며 실내압축강도와 추정압축강도의 추이 그래프를 비교하였다. 비교결과, 본 연구에서 제시된 신뢰도 평가식의 유용성을 확인하였다.

• 보존과학연구
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• 통권34호
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• pp.6-17
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• 2013

봉화 북지리 마애여래좌상은 거대석불로 중립질의 복운모화강암으로 구성되어 있다. 불상에 대한 비파괴 정밀진단 결과, 표면박리 박락, 입상분해 등 다양한 표면손상이 확인되며 물성 또한 취약한 것으로 확인되었다. 또한 사면안정성 평가 결과 전도파괴, 평면 및 쐐기파괴 등의 가능성 제기되었다. 따라서 과학적 보존처리를 통해 암석 물성 강화와 구조적 안정성을 회복시켰으며 기존 보호각이 통풍이 원활치 못한 점과 누수문제 등이 확인되어 이를 보완할 수 있는 보호각으로 개축하였다.

• 산업기술연구
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• 제25권B호
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• pp.115-120
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• 2005

Impact seismic wave method is a method for non-destructive testing of concrete structure using of stress wave which is propagate and reflected from internal flaws within concrete structure and external surface. In this study, we performed frequency domain method using impact seismic wave test for safety diagnosis of civil engineering structure. And reflection method which is used for one-dimensional target such as tunnel lining and transmission method are compared with each other.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.668-674
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• 2002

Structural integrity assessment is indispensable for preventing catastrophic failure of industrial structures/components/facilities. This diagnosis of operating components should be done periodically for safe maintenance and economical repair. However, conventional standard methods for mechanical properties have the problems of bulky specimen, destructive and complex procedure of specimen sampling. Especially, the mechanical properties at welded zone including weldment and heat affected zone could not be evaluated individually due to their size requirement problem. So, an advanced indentation technique has been developed as a potential method for non-destructive testing of in-field structures. This technique measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation such as yield strength, tensile strength and work-hardening index. Also indentation technique can evaluate a residual stress based on the concept that indentation load-depth curves were shifted with the direction and the magnitude of residual stress applied to materials. In this study, we characterized the tensile properties and welding residual stress of various industrial facilities through the new techniques, and the results are introduced and discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1692-1695
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• 1997

This paper describes the relationship between the various non-destructive parameters and the breakdown voltage for the 17 kV, 300 MVA and the 22 kV, 500 MVA generators stator bars with polyester and epoxy/mica insulation respectively. Also, this study reports the results of an investigation into the factors which can assess the insulation condition of generator stator winding. Furthermore, a new parameter, Partial Discharge Index(PDI), is introduced as the valuable parameter for the assessment of insulation condition. The ratio between partial discharge increment and the stepwise voltage increment from the Discharge Inception Voltage (DIV) at the characteristic or resonant frequency band shows the close relationship between the breakdown voltage and PDI.