• 제목/요약/키워드: Energy measurement

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Database of virtual spectrum of artificial radionuclides for education and training in in-situ gamma spectrometry

  • Yoomi Choi;Young-Yong Ji;Sungyeop Joung
    • Nuclear Engineering and Technology
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    • v.55 no.1
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    • pp.190-200
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    • 2023

  • As the field of application of in-situ gamma spectroscopy is diversified, proficiency is required for consistent and accurate analysis. In this study, a program was developed to virtually create gamma energy spectra of artificial nuclides, which are difficult to obtain through actual measurements, for training. The virtual spectrum was created by synthesizing the spectra of the background radiation obtained through actual measurement and the theoretical spectra of the artificial radionuclides obtained by a Monte Carlo simulation. Since the theoretical spectrum can only be obtained for a given geometrical structure, representative major geometries for in-situ measurement (ground surface, concrete wall, radioactive waste drum) and the detectors (HPGe, NaI(Tl), LaBr3(Ce)) were predetermined. Generated virtual spectra were verified in terms of validity and harmonization by gamma spectrometry and energy calibration. As a result, it was confirmed that the energy calibration results including the peaks of the measured spectrum and the peaks of the theoretical spectrum showed differences of less than 1 keV from the actual energies, and that the calculated radioactivity showed a difference within 20% from the actual inputted radioactivity. The verified data were assembled into a database and a program that can generate a virtual spectrum of desired condition was developed.

  • https://doi.org/10.1016/j.net.2022.07.028 인용 PDF

Characteristics Analysis of Measurement Variables for Detecting Anomaly Signs of Thermal Runaway in Lithium-Ion Batteries (리튬이온 배터리의 열폭주 이상징후 감지를 위한 측정 변수 특성 분석)

  • LIM, BYUNG-JU;CHO, SUNG-HOON;LEE, GA-RAM;CHOI, SEOK-MIN;PARK, CHANG-DAE
    • Transactions of the Korean hydrogen and new energy society
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    • v.33 no.1
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    • pp.85-94
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    • 2022

  • To detect anomaly signs of thermal runaway in advance, this study analyzed the signals from various sensors installed in lithium-ion batteries. The thermal runaway mechanism was analyzed, and measurement variables for anomalies of a battery cell were surface temperature, strain, and gas concentration. The changes and characteristics of three variables during the thermal runaway process were analyzed under the abuse environment: the overheat and the overcharge. In experiment, the thermal runaway of the battery proceeded in the initial developing stage, the outgassing stage, and the ignition stage. Analysis from the measured data indicated that the suitable variable to detect all stages of thermal runaway is the surface temperature of the battery, and surface strain is alternative.

  • https://doi.org/10.7316/KHNES.2022.33.1.85 인용 PDF KSCI

Calculation of Vertical Wind Profile Exponents and Its Uncertainty Evaluation - Jeju Island Cases (풍속고도분포지수 산정 및 불확도 평가 - 제주도 사례)

  • Kim, You-Mi;Kim, Hyun-Goo;Kang, Yong-Heack;Yun, Chang-yeol;Kim, Jin-Young;Kim, Chang Ki;Kim, Shin-Young
    • Journal of the Korean Solar Energy Society
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    • v.36 no.4
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    • pp.11-20
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    • 2016

  • For accurate wind resource assessment and wind turbine performance test, it is essential to secure wind data covering a rotor plane of wind turbine including a hub height. In general, we can depict wind speed profile by extrapolating or interpolating the wind speed data measured from a meteorological tower where multiple anemometers are mounted at different heights using a power-law of wind speed profile. The most important parameter of a power-law equation is a vertical wind profile exponent which represents local characteristics of terrain and land cover. In this study, we calculated diurnal vertical wind profile exponents of 8 locations in Jeju Island who possesses excellent wind resource according to the GUM (Guide to the Expression of Uncertainty in Measurement) to evaluate its uncertainty. Expanded uncertainty is calculated by combined standard uncertainty, which is the result of composing type A standard uncertainty with type B standard uncertainty. Although pooled standard deviation should be considered to derive type A uncertainty, we used the standard deviation of vertical wind profile exponent of each day avoiding the difficult of uncertainty evaluation of diurnal wind profile variation. It is anticipated that the evaluated uncertainties of diurnal vertical wind profile exponents at 8 locations in Jeju Island are to be registered as a national standard reference data and widely used in the relevant areas.

  • https://doi.org/10.7836/kses.2016.36.4.011 인용 PDF KSCI