• 제목/요약/키워드: science standard

검색결과 11,221건 처리시간 0.164초

Measurement of Solar Cell Using LED-based Differential Spectral Responsivity Comparator under High Background Irradiance

  • Zaid, Ghufron;Park, Seong-Chong;Lee, Dong-Hoon;Park, Seung-Nam
    • 한국광학회:학술대회논문집
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    • 한국광학회 2009년도 동계학술발표회 논문집
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    • pp.293-294
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    • 2009
  • The spectral responsivity of solar cells has been measured under high background irradiance using an LED-based differential spectral responsivity Comparator (DSR-C). The comparator developed is fully automated and has some advantages: It does not need a chopper to modulate the light. Unlike the conventional method, it does not require a monochromator to select wavelength. It covers a wavelength range up to 1200 nm. The wavelength range of the comparator is limited by the spectral power distribution of the LEDs and the spectral responsivity of the standard detector. An active temperature control was utilized to meet the specified standard conditions of solar cell test. This work shows the effect of different levels of background irradiance on the spectral responsivity and the importance of same background irradiance for solar cell test as specified by the corresponding standard.

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쇼어경도표준의 확립에 관한 연구 (A Study on the Establishment of Shore Hardness Standards)

  • 방건용;탁내형;봉하헌
    • 열처리공학회지
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    • 제15권3호
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    • pp.127-135
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    • 2002
  • Shore hardness test was developed in 1906 to overcome the limit of Brinell hardness test. However, the detailed requirements on the tester was not clearly specified except the scale, i.e., 100 HS for high carbon steel and 10 HS for soft brass. As a result, the shore hardness was used for quite long time without well established standards. For the establishment of hardness standards, standard tester, standard procedure, and standard hardness block must be provided. So far the standard of Shore hardness was maintained by correlating Shore hardness scale to Vickers hardness through converting equation. This is the so called converted Shore hardness and it is not the true Shore hardness standard strictly. In this paper, the possibility of establishing Shore hardness standard based on the Shore standard hardness tester is reported.

100 kN Deadweight Force Standard Machine and Evaluation

  • Park Yon-Kyu;Kim Min-Seok;Kim Jong-Ho;Kang Dae-Im;Song Hou-Keun
    • Journal of Mechanical Science and Technology
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    • 제20권7호
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    • pp.961-971
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    • 2006
  • A deadweight force standard machine is a mechanical structure that generates force by subjecting deadweights to the local gravitational field. The Korea Research Institute of Standards and Science (KRISS) developed and installed a 100 kN deadweight force standard machine for national force standards. It can generate forces from 2 kN to 110 kN in increments of 1 kN. The uncertainty of the force machine was estimated and declared as $2\times10^{-5}$. This 100 kN deadweight force machine was compared with the 500 kN deadweight force standard machine at KRISS and the 20 kN and 50 kN deadweight force standard machines at the National Metrology Institute of Japan (NMIJ). The measurement results showed good agreement between the deadweight force machines, and the accuracy level of the 100 kN deadweight force machine was verified.

인장 물성 측정 불확도 평가 (Estimation of Measurement Uncertainty in Evaluation of Tensile Properties)

  • 허용학;이해무;김동진;박종서
    • 대한기계학회논문집A
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    • 제34권1호
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    • pp.73-78
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    • 2010
  • 재료의 인장 물성 측정 불확도 평가가 수행되었다. 인장 물성 측정에 영향을 주는 불확도의 요인이 구분되어 분석되었고 인장 시험으로부터 측정되는 측정량, 즉 탄성계수, 항복 강도 그리고 인장 강도의 불확도 평가 모델이 본 연구에서 제시되었고 각 측정량에 대한 대응하는 수학적 모델과 측정치로부터 각 측정치의 감도계수를 계산함으로서 유도 되었다. 각 모델에 근거하여 ISO 6892에 따라 결정되는 SUS316LN의 실험적 데이터로부터 인장 물성의 불확도가 평가되었다.

직접 비교법을 이용한 W-Band 밀리미터파 전력 표준 전달 시스템 (A W-Band Millimeter-Wave Power Standard Transfer System Using the Direct Comparison Method)

  • 권재용;강태원;강진섭;이동준
    • 한국전자파학회논문지
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    • 제24권1호
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    • pp.47-54
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    • 2013
  • 본 연구는 국내 최초로 개발된 직접 비교법을 이용한 W-band 밀리미터파 전력 표준 전달 시스템에 대한 것이다. 이 시스템은 75~110 GHz 대역에서 W-band 도파관형 전력감지기의 실효 효율과 교정 인자를 측정하기 위하여 개발되었다. 전력 표준 전달 시스템 구성의 핵심 요소인 방향성 결합기의 반사 특성 평가 기법을 소개하고 실험 결과를 보인다. 구현된 시스템을 이용하여 측정하고자 하는 전력감지기의 교정 인자 측정 결과를 보이고, 불확도 요인에 대하여 고찰한다. 측정 결과를 기준값과 비교하여 W-band 밀리미터파 전력 표준 전달 시스템에 의한 측정의 유효성을 검증한다.

On the STSP Normal Distribution

  • Choi, Jeen-Kap
    • Journal of the Korean Data and Information Science Society
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    • 제16권2호
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    • pp.451-456
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    • 2005
  • We introduce the standard two-sided power normal distribution and consider the relation between the probability in standard two-sided power distribution and the probability in standard two-sided power normal distribution and obtain the even moment of the special two-sided power normal distribution including the cases considered by Gupta and Nadarajah(2004)

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Physicochemical Quality Properties of Loin and Tenderloin Ham from Sows

  • Kim, Gye-Woong;Kim, Hack-Youn
    • 한국축산식품학회지
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    • 제40권3호
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    • pp.474-483
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    • 2020
  • This study was conducted to investigate the physicochemical properties of hams obtained from loin and tenderloin cuts from standard pigs and sows. pH levels of loin ham before cooking, standard pig was significantly lower than that of sow (p<0.001). The lightness (L*) and yellowness (b*) values of loin ham from standard pigs were significantly higher than those of sow loin ham (p<0.001). The water-holding capacity (WHC) and curing yield of sow loin was significantly higher than standard loin (p<0.01). The cooking loss of standard pig loin ham was significantly higher than that of sow loin ham (p<0.01). Differences in sensory quality evaluation, except in the case of tenderness, for the two loin hams were not significant. pH levels of tenderloin ham before cooking, standard pig was significantly lower than that of sow (p<0.001). Redness (a*) values of before and after cooking tenderloin ham of sow was higher than that of standard pig (p<0.001). L* values of tenderloin ham of standard pig was significantly higher than that of sow (p<0.001). WHC and curing yield of tenderloin ham from sow was significantly higher than that from a standard pig (p<0.001, p<0.05). The cooking losses of sow and standard pig tenderloin ham were 26.06% and 28.31%, respectively (p<0.001). Differences in sensory quality evaluation, except in the case of tenderness and color, for the two tenderloin hams were not significant. In conclusion, sow pigs loin and tenderloin is suitable for ham product more than standard pigs loin and tenderloin.