Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of...Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of a 241Am–Be source. The measured total neutron ambient dose equivalent rates, H*(10)' tot, were analyzed to obtain the direct neutron ambient dose equivalent rates, H*(10)' dir, using the ISO 8529-2-recommended generalized- fit method, semiempirical fit method, and reducedfitting method (RFM) fit methods. The calibration factor (CF), defined as the ratio between the conventional true value of the neutron ambient dose equivalent rates in a free field, H*(10)' FF, and H*(10)' dir, was evaluated as one of the important characteristics of the neutron meters in the present work. The fitting results show that the H*(10)' dir values of the meters are in good agreement within the theoretical data within 4%. The averaged CFs of the three neutron meters were evaluated as 0:99 ± 0:01, 1:00 ± 0.03;and 0:99 ± 0:08, respectively. The largest standard uncertainty of these values was determined to be approximately 18.47%(k =1). The standard uncertainty of the CFs obtained using the RFM method was less than 4.23%(k=1), which is the smallest uncertainty among the three methods.展开更多
Correction factors of both Rem-meters, the 10 inch diameter single-sphere Remmeter and the standard A-B Rem-meter, were estimated for measuring high energy neutron dose equivalent outside a concrete shielding wall and...Correction factors of both Rem-meters, the 10 inch diameter single-sphere Remmeter and the standard A-B Rem-meter, were estimated for measuring high energy neutron dose equivalent outside a concrete shielding wall and the effects that the emitted neutron spectra become remarkably "harder" penetrated through a concrete shielding wall, and the energy response of the Rem-meter were taken in account. The estimated results could be applied in the measurement of neutron dose equivalent for the intermediate energy heavy ion reactions to avoid the difficulty induced by the energy response of the Rem-meters.展开更多
Vibration intensity and non-dimensional amplitude parameters are often used to extract the fault trend of rotary machines. But,they are the parameters related to energy,and can not describe the fault trend because of ...Vibration intensity and non-dimensional amplitude parameters are often used to extract the fault trend of rotary machines. But,they are the parameters related to energy,and can not describe the fault trend because of varying load and conditions or too slight change of vibration signal. For this reason,three non-dimensional parameters are presented,namely waveform repeatability factor,waveform jumping factor and waveform similarity factor,called as waveform factors jointly,which are based on statistics analysis for the waveform and sensitive to the change of signal waveform. When they are used to extract the fault trend of rotary machines as a kind of technology of instrument and meter,they can reflect the fault trend better than the vibration intensity,peak amplitude and margin index.展开更多
土壤侵蚀是影响全球土地退化和可持续发展的重大环境问题。土壤侵蚀模型可估算土壤流失的空间和时间分布,为制定流域水土资源保护政策与实施有效战略提供支持。修订版通用土壤流失方程(RUSLE,Revised Universal Soil Loss Equation)模...土壤侵蚀是影响全球土地退化和可持续发展的重大环境问题。土壤侵蚀模型可估算土壤流失的空间和时间分布,为制定流域水土资源保护政策与实施有效战略提供支持。修订版通用土壤流失方程(RUSLE,Revised Universal Soil Loss Equation)模型以其兼具简单性与准确性,成为全球应用最广泛的土壤侵蚀模型之一。在RUSLE模型的输入参数中,地形因子(LS因子)对土壤流失潜力的影响最为显著,而LS因子的输入数据和计算方法对最终RUSLE模型计算的质量会有直接影响。为此构建了中国区域30米分辨率LS因子数据集(LS_China)。本数据集采用开源工具SAGA(自动化地球科学分析系统)和GDAL(地理空间数据抽象库),基于公开的SRTM30米高程数据集(SRTMGL1)计算获得,覆盖整个中国区域。数据被组织成单独的栅格化图块,每个栅格化图块覆盖1°×1°的范围,以Geotiff格式存储。在大尺度范围的数据计算过程中,基于对数据的空间分解,采用邻域依赖的计算方法,同时采用多流算法,保证LS因子计算的准确性。在数据质量控制方面,通过变异系数(CV)验证并与同一区域的其他数据集进行比较。结果表明,LS_China数据集的变异系数为1.24,相较于其他数据集,其内部异质性较小,具备高质量和高可靠性。本数据集可用作各种尺度(地方、区域、国家)的任何土壤侵蚀评估的输入数据。展开更多
In recent years, semiconductor survey meters have been developed and are in increasing demand worldwide. This study determined if it is possible to use the X-ray system installed in each medical facility to calculate ...In recent years, semiconductor survey meters have been developed and are in increasing demand worldwide. This study determined if it is possible to use the X-ray system installed in each medical facility to calculate the time constant of a semiconductor survey meter and confirm the meter’s function. An additional filter was attached to the medical X-ray system to satisfy the standards of N-60 to N-120, more copper plates were added as needed, and the first and second half-value layers were calculated to enable comparisons of the facility’s X-ray system quality with the N-60 to N-120 quality values. Next, we used a medical X-ray system to measure the leakage dose and calculate the time constant of the survey meter. The functionality of the meter was then checked and compared with the energy characteristics of the meter. The experimental results showed that it was possible to use a medical X-ray system to reproduce the N-60 to N-120 radiation quality values and to calculate the time constant from the measured results, assuming actual leakage dosimetry for that radiation quality. We also found that the calibration factor was equivalent to that of the energy characteristics of the survey meter.展开更多
基金supported by the Ministry of Science and Technology of Vietnam under Grant 07/HD/DTCB
文摘Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of a 241Am–Be source. The measured total neutron ambient dose equivalent rates, H*(10)' tot, were analyzed to obtain the direct neutron ambient dose equivalent rates, H*(10)' dir, using the ISO 8529-2-recommended generalized- fit method, semiempirical fit method, and reducedfitting method (RFM) fit methods. The calibration factor (CF), defined as the ratio between the conventional true value of the neutron ambient dose equivalent rates in a free field, H*(10)' FF, and H*(10)' dir, was evaluated as one of the important characteristics of the neutron meters in the present work. The fitting results show that the H*(10)' dir values of the meters are in good agreement within the theoretical data within 4%. The averaged CFs of the three neutron meters were evaluated as 0:99 ± 0:01, 1:00 ± 0.03;and 0:99 ± 0:08, respectively. The largest standard uncertainty of these values was determined to be approximately 18.47%(k =1). The standard uncertainty of the CFs obtained using the RFM method was less than 4.23%(k=1), which is the smallest uncertainty among the three methods.
文摘Correction factors of both Rem-meters, the 10 inch diameter single-sphere Remmeter and the standard A-B Rem-meter, were estimated for measuring high energy neutron dose equivalent outside a concrete shielding wall and the effects that the emitted neutron spectra become remarkably "harder" penetrated through a concrete shielding wall, and the energy response of the Rem-meter were taken in account. The estimated results could be applied in the measurement of neutron dose equivalent for the intermediate energy heavy ion reactions to avoid the difficulty induced by the energy response of the Rem-meters.
文摘Vibration intensity and non-dimensional amplitude parameters are often used to extract the fault trend of rotary machines. But,they are the parameters related to energy,and can not describe the fault trend because of varying load and conditions or too slight change of vibration signal. For this reason,three non-dimensional parameters are presented,namely waveform repeatability factor,waveform jumping factor and waveform similarity factor,called as waveform factors jointly,which are based on statistics analysis for the waveform and sensitive to the change of signal waveform. When they are used to extract the fault trend of rotary machines as a kind of technology of instrument and meter,they can reflect the fault trend better than the vibration intensity,peak amplitude and margin index.
文摘土壤侵蚀是影响全球土地退化和可持续发展的重大环境问题。土壤侵蚀模型可估算土壤流失的空间和时间分布,为制定流域水土资源保护政策与实施有效战略提供支持。修订版通用土壤流失方程(RUSLE,Revised Universal Soil Loss Equation)模型以其兼具简单性与准确性,成为全球应用最广泛的土壤侵蚀模型之一。在RUSLE模型的输入参数中,地形因子(LS因子)对土壤流失潜力的影响最为显著,而LS因子的输入数据和计算方法对最终RUSLE模型计算的质量会有直接影响。为此构建了中国区域30米分辨率LS因子数据集(LS_China)。本数据集采用开源工具SAGA(自动化地球科学分析系统)和GDAL(地理空间数据抽象库),基于公开的SRTM30米高程数据集(SRTMGL1)计算获得,覆盖整个中国区域。数据被组织成单独的栅格化图块,每个栅格化图块覆盖1°×1°的范围,以Geotiff格式存储。在大尺度范围的数据计算过程中,基于对数据的空间分解,采用邻域依赖的计算方法,同时采用多流算法,保证LS因子计算的准确性。在数据质量控制方面,通过变异系数(CV)验证并与同一区域的其他数据集进行比较。结果表明,LS_China数据集的变异系数为1.24,相较于其他数据集,其内部异质性较小,具备高质量和高可靠性。本数据集可用作各种尺度(地方、区域、国家)的任何土壤侵蚀评估的输入数据。
文摘In recent years, semiconductor survey meters have been developed and are in increasing demand worldwide. This study determined if it is possible to use the X-ray system installed in each medical facility to calculate the time constant of a semiconductor survey meter and confirm the meter’s function. An additional filter was attached to the medical X-ray system to satisfy the standards of N-60 to N-120, more copper plates were added as needed, and the first and second half-value layers were calculated to enable comparisons of the facility’s X-ray system quality with the N-60 to N-120 quality values. Next, we used a medical X-ray system to measure the leakage dose and calculate the time constant of the survey meter. The functionality of the meter was then checked and compared with the energy characteristics of the meter. The experimental results showed that it was possible to use a medical X-ray system to reproduce the N-60 to N-120 radiation quality values and to calculate the time constant from the measured results, assuming actual leakage dosimetry for that radiation quality. We also found that the calibration factor was equivalent to that of the energy characteristics of the survey meter.
