• Title, Summary, Keyword: 표준소급성

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Quantifying Uncertainty in Cadmium Analytical Measurements (카드뮴 분석에서의 측정불확도 추정)

  • Kang, Kil-Jin;Sun, Nam-Kyu
    • Food Science and Industry
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    • v.40 no.1
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    • pp.27-35
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    • 2007
  • 측정불확도란 시험결과에 대하여 측정량을 합리적으로 추정한 값들의 분산 특성을 나타내는 파라미터(parameter)로써 ILAC(국제시험소인정협력체) 등의 국제기구와의 측정결과에 대한상호인정 및 신뢰성 확보에 필수적인 요소이다. 국제표준(ISO/IEC 17025)에 맞는 시험분석 결과의 도출을 위해서는 먼저 소급성을 유지하고 그에 따른 불확도를 산출하여야 한다. 소급성은 실험의 모든 과정에 불확도를 가지고 끊기지 않는 비교연결을 통한 국제(국가)표준과 연관시키는 시스템으로, sampling에서 측정결과의 도출까지 소급성을 유지하는 것만이 측정결과의 신뢰성(정확 및 정밀)을 유지하는 최상의 시스템이다. Guide to the Expression of Uncertainty in Measurements(GUM)에 의한 불확도 계산 절차는 측정량(measurand)의 함수 표현, 입력량의 표준불확도(standard uncertainty)의 계산(표준편차, 평균의 표준편차), 합성표준불확도(combined uncertainty)의 계산, 확장불확도(expanded uncertainty)의 계산을 통한 통계적 추정을 하는 것이다. 오렌지 쥬스 중 카드뮴을 분석함에 있어서, 실험실에 대해서는 국제표준화(ISO17025) 시스템을 도입하고 분석시약 및 기기에 대하여 소급성을 유지하여, 분석결과의 신뢰성을 확보하기 위한 측정불확도를 산출하였다.

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Measurement of Traceability Error for Calibration Service Center Using Type S Thermocouples (S형 열전대를 이용한 교정검사기관의 소급성 오차측정)

  • Gam, Kee-Sool;Kim, Yong-Gyoo;Kim, Sun-Gon
    • Journal of Sensor Science and Technology
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    • v.4 no.1
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    • pp.43-50
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    • 1995
  • We measured the traceability error for nine high temperature calibration service centers including KRISS through the round-robin test. In this test the type S thermocouple, which used as a calibration standard thermometer commonly, was accommodated as a test thermocouple. Intercomparison data of three institutions were coincident with KRISS's data within ${\pm}0.5^{\circ}C$, which was the calibration uncertainty of the type S thermocouple, but the remaining six institution's data were deviated from the assigned uncertainty level. Deviation of the intercomparison data increased gradually according to the increase of the test temperature. and the maximum difference was so large as about $2.0^{\circ}C$ at the highest test temperature, gold point. In this study we found the traceability error of high temperature calibration service center for a high temperature standard was within $2.0^{\circ}C$.

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Certification of magnification standards for the establishment of meter-traceability in microscopy (현미경의 길이표준 소급성 확립을 위한 배율 교정 시편 인증)

  • Kim J.A.;Kim J.W.;Park B.C.;Eom T.B.;Kang C.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.645-648
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    • 2005
  • Microscopy has enabled the development of many advanced technologies, and higher level microscopic techniques are required according to the increase of research in nano-technology and bio-technology fields. Therefore, in many applications, we need to measure the dimension of micro-scale parts accurately, not just to observe their shapes. To establish the meter-traceability in microscopy, gratings have been widely used as a magnification standard. KRISS provides the certification service of magnification standards using an optical diffractometer and a metrological AFM (MAFM). They are based on different measurement principles, and so can give complementary information for each other. In this paper, we describe the configuration of each system and measurement procedures to certificate grating pitch values of magnification standards. Several measurement results are presented, and the discussion about them are also given. Using the optical diffractometer, we can calibrate a grating specimen with uncertainty of less than 50 pm. The MAFM can measure a grating specimen of down to 100 nm pitch value, and the calibrated values usually have uncertainty less than 500 pm.

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Calibration and Performance Test of Electro-optical Distance Meters Using a Laser Interferometer (레이저 간섭계를 이용한 광파거리측정기의 교정과 특성분석)

  • Kim Jae Wan;Eom Tae Bong;Suh Ho Suhng
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.22 no.4
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    • pp.367-374
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    • 2004
  • In order for the measurement results of an electro-optical distance meter(EDM), which is widely used in surveying, to be reliable, an EDM should be calibrated. For the calibration of an EDM, we have settled a traceability chain, which connects the EDM under calibration to the definition of metre. The chain starts from the iodine stabilized He-Ne laser which realizes the definition of metre, and then connected to a stabilized laser interferometer, a standard EDM, and finally to the EDM under calibration through the baseline. We achieved the expanded calibration uncertainties of the scale and length measurement of an EDM being evaluated to be 6$\times$10$^{-6}$ and 0.2 mm, respectively. Two different calibration methods, and their results are compared.

Measurements of Two-dimensional Gratings Using a Metrological Atomic Force Microscope and Uncertainty Evaluation (길이 표준 소급성을 갖는 원자간력 현미경을 이용한 2차원 격자 시편 측정과 불확도 평가)

  • Kim, Jong-Ahn;Kim, Jae-Wan;Kang, Chu-Shik;Eom, Tae-Bong
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.9
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    • pp.68-75
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    • 2007
  • The pitch and orthogonality of two-dimensional (2D) gratings have been measured by using a metrological atomic force microscope (MAFM) and measurement uncertainty has been analyzed. Gratings are typical standard artifacts for the calibration of precision microscopes. Since the magnification and orthogonality in two perpendicular axes of microscopes can be calibrated simultaneously using 2D gratings, it is important to certify the pitch and orthogonality of 2D gratings accurately for nano-metrology using precision microscopes. In the measurement of 2D gratings, the MAFM can be used effectively for its nanometric resolution and uncertainty, but a new measurement scheme was required to overcome some limitations of current MAFM such as nonnegligible thermal drift and slow scan speed. Two kinds of 2D gratings, each with the nominal pitch of 300 nm and 1000 nm, were measured using line scans for the pitch measurement of each direction. The expanded uncertainties (k = 2) of measured pitch values were less than 0.2 nm and 0.4 nm for each specimen, and those of measured orthogonality were less than 0.09 degree and 0.05 degree respectively. The experimental results measured using the MAFM and optical diffractometer were coincident with each other within the expanded uncertainty of the MAFM. As a future work, we also proposed another scheme for the measurements of 2D gratings to increase the accuracy of calculated peak positions.

Pitch Measurement of One-dimensional Gratings Using a Metrological Atomic Force Microscope and Uncertainty Evaluation (미터 소급성을 갖는 원자간력 현미경을 이용한 1차원 격자 피치 측정과 불확도 평가)

  • Kim Jong-Ahn;Kim Jae Wan;Park Byong Chon;Eom Tae Bong;Kang Chu-Shik
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.4
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    • pp.84-91
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    • 2005
  • We measured the pitch of one-dimensional (ID) grating specimens using a metrological atomic force microscope (M-AFM). The ID grating specimens a.e often used as a magnification standard in nano-metrology, such as scanning probe microscopy (SPM) and scanning electron microscopy (SEM). Thus, we need to certify the pitch of grating specimens fur the meter-traceability in nano-metrology. To this end, an M-AFM was setup at KRISS. The M-AFM consists of a commercial AFM head module, a two-axis flexure hinge type nanoscanner with built-in capacitive sensors, and a two-axis heterodyne interferometer to establish the meter-traceability directly. Two kinds of ID grating specimens, each with the nominal pitch of 288 nm and 700 nm, were measured. The uncertainty in pitch measurement was evaluated according to Guide to the Expression of Uncertainty in Measurement. The pitch was calculated from 9 line scan profiles obtained at different positions with 100 ㎛ scan range. The expanded uncertainties (k = 2) in pitch measurement were 0.10 nm and 0.30 nm for the specimens with the nominal pitch of 288 nm and 700 nm. The measured pitch values were compared with those obtained using an optical diffractometer, and agreed within the range of the expanded uncertainty of pitch measurement. We also discussed the effect of averaging in the measurement of mean pitch using M-AFM and main components of uncertainty.

Development of a Metrological Atomic Force Microscope for the Length Measurements of Nanometer Range (나노미터 영역 길이 측정 위한 미터 소급성을 갖는 원자간력 현미경 개발)

  • 김종안;김재완;박병천;엄태봉;홍재완
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.11
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    • pp.75-82
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    • 2004
  • A metrological atomic force microscope (M-AFM) was developed fur the length measurements of nanometer range, through the modification of a commercial AFM. To eliminate nonlinearity and crosstalk of the PZT tube scanner of the commercial AFM, a two-axis flexure hinge scanner employing built-in capacitive sensors is used for X-Y motion instead of PZT tube scanner. Then two-dimensional displacement of the scanner is measured using two-axis heterodyne laser interferometer to ensure the meter-traceability. Through the measurements of several specimens, we could verify the elimination of nonlinearity and crosstalk. The uncertainty of length measurements was estimated according to the Guide to the Expression of Uncertainty in Measurement. Among several sources of uncertainty, the primary one is the drift of laser interferometer output, which occurs mainly from the variation of refractive index of air and the thermal stability. The Abbe error, which is proportional to the measured length, is another primary uncertainty source coming from the parasitic motion of the scanner. The expanded uncertainty (k =2) of length measurements using the M-AFM is √(4.26)$^2$+(2.84${\times}$10$^{-4}$ ${\times}$L)$^2$(nm), where f is the measured length in nm. We also measured the pitch of one-dimensional grating and compared the results with those obtained by optical diffractometry. The relative difference between these results is less than 0.01 %.

Realization of the national standard of candela traceable to the absolute cryogenic radiometer at KRISS (극저온 절대복사계에 소급한 칸델라 국가표준 실현)

  • Park, Seung-Nam;Kim, Yong-Wan;Lee, Dong-Hoon
    • Korean Journal of Optics and Photonics
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    • v.15 no.5
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    • pp.443-448
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    • 2004
  • We realized the national standard of the candela, one of the SI units, by using two photometers with the spectral responsivity measured in reference to the absolute cryogenic radiometer. The external apertures of the photometers were fabricated using a diamond turning machine, and measured in terms of area with uncertainty of 0.05 %(k = 1). The candela is realized using a 1 kW FEL lamp and the characterized photometers on an optical bench. The uncertainty is budgeted to be 0.25 %(k = 1) considering the uncertainty of the spectral responsivity and the response uniformity of the detectors, the area of the external apertures, the color temperature of the lamp, and the positioning reproducibility of the photometers and the lamp. We verified the realized scale by comparing with the scale of National Institute of Standards and Technology, USA. They coincided with each other within 0.1%.

A Development of Sheet Resistance Meter for Thin Film Materials (박막 재료의 면저항 측정기 개발)

  • Kang, Jeon-Hong;Yu, Kwang-Min;Kim, Han-Jun;Han, Sang-Ok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.233-234
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    • 2009
  • 박막 재료의 면저항 측정은 일반적으로 FPP(Four-Point Probe)원리를 적용한 측정기률 사용하고 있다. 개발된 면저항 측정기의 특징은 dual configuration 기술을 적용하여 탐침 간격에 대한 시료의 크기 및 두께에 대한 보정계수를 고려하지 않아도 되므로 누구나 업고 정확하게 사용 할 수 있다. 측정범위는 $1\;m{\Omega}{/\square}\;{\sim}\;1\;G{\Omega}{/\square}$이며, 반복성과 재현성 및 직선성은 0.1 %이하로서 우수한 특성을 나타냈다. 또한 기존의 면저항 측정기에 적용된 single configuration 기술에서 나타나는 가장자리 효과의 단점을 dual configuration 기술을 적용하여 해결하였고 정밀 정확도를 향상시켰다. 개발된 면저항 측정기의 특성평가는 국가측정표준으로부터 소급성이 유지된 표준저항, 분할저항기, 면저항 인증표준물질 등을 사용하였다.

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The Introduction of the Final Proposal for the High-current Standard Measurement System (대전류 표준측정시스템에 대한 STL 최종방안의 소개)

  • Jeong, J.Y.;Shin, Y.J.;Kim, I.S.;Kim, M.K.;Lee, J.G.;Kim, M.H.;Lee, Y.H.
    • Proceedings of the KIEE Conference
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    • pp.403-405
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    • 2003
  • 본 논문에서는 대전류 표준측정에 대한 STL TC의 Ad-Hoc Working Group의 최종방안에 대해 자세히 소개하여 이를 계기로 국내에서도 필요한 사전준비에 만전을 기하고자 한다. 향후 연속적으로 해야 할 업무, Shunt의 소유, 경비 지불방법 등에 대한 사항과 함께 우리나라 대전류 표준측정시스템의 구축절차를 제안하였으며, 이를 통해 대전류 측정에 있어서 국제표준과의 소급성을 확보할 수 있기 때문에 국내에서 시행하는 각종 시험에서 대전류 측정이 국제적으로 유효하게 될 것이다.

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