FWHM calibration is one of the essential procedures in gamma-ray spectra analysis.Traditional method is time consumption and poor flexibility because of extra measurement on calibration source.This paper introduces an...FWHM calibration is one of the essential procedures in gamma-ray spectra analysis.Traditional method is time consumption and poor flexibility because of extra measurement on calibration source.This paper introduces an implicit calibration method based on symmetric zero-area conversion.The single peaks can be differentiated from doublets.Meanwhile,the extracted FWHM values can be applied in the fitting process.Various forms of calibration equations are introduced and compared with practical spectrum data under this method.展开更多
The Lyapunov exponents of synchronous 12-lead ECG signals have been investigated for the first time using a multi-sensor (electrode) technique. The results show that the Lyapunov exponents computed from different loca...The Lyapunov exponents of synchronous 12-lead ECG signals have been investigated for the first time using a multi-sensor (electrode) technique. The results show that the Lyapunov exponents computed from different locations on the body surface are not the same, but have a distribution characteristic for the ECG signals recorded from coronary artery disease (CAD) patients with sinus rhythms and for signals from healthy older people. The maximum Lyapunov exponent L1 of all signals is positive. While all the others are negative, so the ECG signal has chaotic characteristics. With the same leads, L1 of CAD patients is less than that of healthy people, so the CAD patients and healthy people can be classified by L1, L1 therefore has potential values in the diagnosis of heart disease.展开更多
基金Supported by National Nature Science Foundation of China(No.11175101)
文摘FWHM calibration is one of the essential procedures in gamma-ray spectra analysis.Traditional method is time consumption and poor flexibility because of extra measurement on calibration source.This paper introduces an implicit calibration method based on symmetric zero-area conversion.The single peaks can be differentiated from doublets.Meanwhile,the extracted FWHM values can be applied in the fitting process.Various forms of calibration equations are introduced and compared with practical spectrum data under this method.
基金This work was supported by Tsinghua University (Grant No. 0009).
文摘The Lyapunov exponents of synchronous 12-lead ECG signals have been investigated for the first time using a multi-sensor (electrode) technique. The results show that the Lyapunov exponents computed from different locations on the body surface are not the same, but have a distribution characteristic for the ECG signals recorded from coronary artery disease (CAD) patients with sinus rhythms and for signals from healthy older people. The maximum Lyapunov exponent L1 of all signals is positive. While all the others are negative, so the ECG signal has chaotic characteristics. With the same leads, L1 of CAD patients is less than that of healthy people, so the CAD patients and healthy people can be classified by L1, L1 therefore has potential values in the diagnosis of heart disease.
