• 제목/요약/키워드: Detection sensitivity

검색결과 2,447건 처리시간 0.036초

휴대용 XRF 장치의 검출감도 향상에 관한 연구 (Study for Enhancement of the Detection Sensitivity in Hand-Held X-Ray Fluorescence Device)

  • 김성수;이연승;김도윤;고동섭
    • 한국진공학회지
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    • 제20권6호
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    • pp.409-415
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    • 2011
  • 현재 개발 중인 휴대용 XRF (X-Ray Fluorescence) 장치의 검출감도를 향상시키기 위한 방법을 논의하였다. 대기 기체분자에 의한 강도 손실을 최소화하기 위하여 시료와 검출기 사이에 Vacuum module을 설치하였다. Vacuum module은 대기기체 또는 He 기체를 채울 수 있도록 고안하였다. 그리고 Vacuum module 내부에 He 기체를 채운 상태, 또는 진공상태에서 검출감도의 변화를 조사하였다. 그 결과 다음 3가지 중요한 결과를 얻었다. 첫 번째는, 낮은 에너지 영역(3~4 keV)에서의 XRF 강도가 2~4배 정도 증가하였다. 검출감도의 향상은 검출시간의 단축을 의미하기 때문에, 휴대용 XRF 장치에 있어서 매우 중요한 결과이다. 두 번째는, x-ray emission line의 에너지가 3 keV 이하인 원소의 검출 가능성을 확인하였다. 세 번째는, He 기체를 채운 vacuum module을 사용하면, 휴대용 XRF 장치에 진공밀폐용기를 쓰지 않으면서도 대기기체분자에 의한 흡수를 최소화할 수 있다는 것이다. 세 가지 모두 휴대용 XRF 장치의 개발에 있어서 매우 의미있는 결과로 판단된다.

MURA Detection Method using a Slit-Beam-Profile Ellipsometer

  • Murai, Hideyuki;Ekawa, Koichi;Takashima, Jun;Naito, Hitoshi;Nakatsuka, Nobuo
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1465-1468
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    • 2006
  • We developed a new ellipsometer for MURA detection. This ellipsometer can measure MURA along the slit line on the sample with high sensitivity, because this ellipsometer irradiates a slit beam onto the sample but can reject the reflected light from the back surface of the substrate. This ellipsometer is suitable for measuring MURA of the surface of sample with high sensitivity.

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동특성 변화를 이용한 구조물의 손상 탐지 해석 (Analysis of a Structural Damage Detection using the Change of Dynamic Characteristics)

  • 이정윤;이정우;이준호
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.760-763
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    • 2003
  • This study proposed the analysis of damage defection due to the change of the stiffness of structure by using the original and modified dynamic characteristics. The method is applied to examples of a cantilever and 3 degree of freedom by modifying the stiffness. The predicted damage detections are in good agreement with these from the structural reanalysis using the modified stiffness.

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식중독균 검출의 민감도 향상을 위한 Emulsion PCR 적용 (Emulsion PCR Improves the Specificity and Sensitivity of PCR-based Pathogen Detection)

  • 채창훈
    • Journal of Dairy Science and Biotechnology
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    • 제34권1호
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    • pp.43-49
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    • 2016
  • Emulsion PCR (ePCR) has recently gained interest in the areas of food safety and biotechnology owing to its highly specific and sensitive performance in the amplification of target DNA. To facilitate the applications of ePCR to food safety and biotechnology, this paper describes the principles of ePCR and the factors that should be considered in designing ePCR. In addition, current research and applications related to ePCR are discussed.

Detection filter에 기초한 고장검출기법 적용에 관한 연구 (Application of The Fault Detection Filter For Dynamics Failure Detection)

  • 김정근;장태규
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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    • pp.55-58
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    • 2001
  • 본 논문에서는 해석적인 모델에 기초한 고장 검출 기법의 하나인 fault detection filter를 적용한 고장 검출 알고리듬을 개발하고 이를 적용하여 고장검출 필터의 유효성을 보이고자 한다. Fault detection filter는 특수한 형태의 observer로써 특정한 고장의 발생시 잔차가 출력 공간에서 일정한 방향을 유지함으로써 고장 개소의 판별이 가능하다. 이에 본 논문에서는 fault detection filter에 기초한 고장 감지 시스템을 적용하기 위한 다이나믹 시스템 모델링과 고장감지 시스템의 설계과정 및 이를 적용 모의시험 결과를 수록하였다. 결과를 통하여 fault detection filter가 갖는 방향성에 대한 sensitivity 효과를 고장 감지 목적에 유효하게 적용할 수 있음을 보였다.

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RF front-end Module for On-Line UHF Partial-discharge Monitoring System

  • Lee June Young;Kim Bok Ki
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2004년도 학술대회지
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    • pp.776-779
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    • 2004
  • A RF front-end module is designed for GIS(Gas Insulated Substation) which is employed for effective and efficient very high voltage transmission. Major advantage of the unit is improved PO detection sensitivity through minimizing the effect of surrounding interference signals, which is achieved by controlling the gain and the selection of the frequency band, for the precise detection of any UHF PO (Partial Discharge) disturbance occurred in the GIS due to some unwanted problems. For the development of the module, various switches for providing selected signal paths, wideband LNA, 3 BPF for selecting detection frequency band, and video detector are designed, fabricated and measured on 1 mm FR4 substrate with various RF components. The detection sensitivity of the unit was <-60 dBm that is sufficient to detect UHF PO signals as low as 1 pC. It is believed that the value is enough to detect the signal occurred in GIS.

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신세포암에서 $^{18}F-FDG-PET/CT$ ($^{18}F-FDG-PET/CT$ in Renal Cell Carcinoma)

  • 전태주
    • Nuclear Medicine and Molecular Imaging
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    • 제42권sup1호
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    • pp.126-129
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    • 2008
  • Renal cell carcinoma is the most common histological type of renal malignancy, predominant in men and the primary treatment modality of this tumor is surgery. The role of diagnostic imaging in the management of this tumor is the evaluation of extent of disease as well as the detection and characterization of renal mass. US has long been a routine screening tool for kidney but tomographic imaging modalities such as CT and MRI begin to be also commonly used these days. On the other hand, the sensitivity of $^{18}F-FDG-PET$ in detection of renal mass is relatively low because of inherent limitation caused by FDG excretion pathway despite avid uptake of FDG to tumor cell per se. Many studies revealed FDG PET scan could play an important role in detection of metastatic lesions although the sensitivity for the detection of primary lesion is not so high. Furthermore, development of PET/CT scanner will make it possible to expand the indication of FDG PET scan in this malignancy.

동특성 변화를 이용하여 보의 다중 균열 위치 및 크기 해석 (Multi-crack Detection of Beam Using the Change of Dynamic Characteristics)

  • 김정호;이정우;이정윤
    • 한국소음진동공학회논문집
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    • 제25권11호
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    • pp.731-738
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    • 2015
  • This study proposed the method of the multi-crack detection using the sensitivity coefficient matrix which is calculated from the change of eigenvalues and eigenvectors before and after the crack. Each crack is modeled by a rotational springs. The method is applied to the cantilever beam with miulti-crack. The eigenvalues and eigenvectors are determined for different crack locations and depths. The prediction of multi-crack detection are in good agreement with the results of structural reanalysis.

Development of Array-based Technology for Detection of HAV Using Gold-DNA Probes

  • Wan, Zhixiang;Wang, Yefu;Li, Shawn Shun-Cheng;Duan, Lianlian;Zhai, Jianxin
    • BMB Reports
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    • 제38권4호
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    • pp.399-406
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    • 2005
  • A sensitive method for detection of Hepatitis A virus (HAV) by utilizing gold-DNA probe on an array was developed. Amino- modified oligodeoxynucleotides at the 5' position were arrayed on an activated glass surface to function as capture probes. Sandwich hybridization occurred among capture probes, the HAV amplicon, and gold nanoparticle-supported oligonucleotide probes. After a silver enhancement step, signals were detected by a standard flatbed scanner or just by naked eyes. As little as 100 fM of HAV amplicon could be detected on the array. Therefore, the array technology is an alternative to be applied in detection of HAV due to its low-cost and high-sensitivity.

Disposable in-field electrochemical potable sensor system for free available chlorine (FAC) detection

  • Chang, Seung-Cheol;Park, Deog-Su
    • 센서학회지
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    • 제16권6호
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    • pp.449-456
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    • 2007
  • The work described in this study concerns the development of a disposable amperometric sensor for the electrochemical detection of a well-known aqueous pollutant, free available chlorine (FAC). The FAC sensor developed used screen printed carbon electrodes (SPCEs) coupled with immobilised syringaldazine, commonly used as an indicator in photometric FAC detection, which was directly immobilised on the surface of SPCEs using a photopolymer PVA-SbQ. To enable in-field analysis of FAC, a prototype hand-held electrochemical analyzer has been developed to withstand the environment with its rugged design and environmentally sealed connections; it operates from two PP3 (9 volt) batteries and is comparable in accuracy and sensitivity to commercial bench top systems. The sensitivity of the FAC sensor developed was $3.5{\;}nA{\mu}M^{-1}cm^{-2}$ and the detection limit for FAC was found to be $2.0{\;}{\mu}M$.