Nonlinear science research is a hot point in the world.It has deepened our cognition of determinism and randomicity,simplicity and com-plexity,noise and order and it will profoundly influ-ence the progress of the stud...Nonlinear science research is a hot point in the world.It has deepened our cognition of determinism and randomicity,simplicity and com-plexity,noise and order and it will profoundly influ-ence the progress of the study of natural science,including life science.Life is the most complex nonlinear system and heart is the core of lifecycle system.In the late more than 20 years,nonlinear research on heart electric activities has made much headway.The commonly used parameters are based on chaos and fractal theory,such as correlation dimension,Lyapunov ex-ponent,Kolmogorov entropy and multifractal singu-larity spectrum.This paper summarizes the commonly used methods in the nonlinear study of heart electric signal.Then,considering the shortages of the above tradi-tional nonlinear parameters,we mainly introduce the results on short-term heart rate variability(HRV)signal(500 R-R intervals)and HFECG signal(1-2s).Finally,we point out it is worthwhile to put emphasis on the study of the sensitive nonlinearity parameters of short-term heart electric signal and their dynamic character and clinical effectivity.展开更多
Using YBa2Cu3O7-δ/MgO bicrystal Josephson junction,we have developed a setup for spectrum analyses of terahertz signals,up to 2.5 THz,with a frequency resolution of 3 GHz.The junction works at liquid nitrogen tempera...Using YBa2Cu3O7-δ/MgO bicrystal Josephson junction,we have developed a setup for spectrum analyses of terahertz signals,up to 2.5 THz,with a frequency resolution of 3 GHz.The junction works at liquid nitrogen temperature when the signal frequencies are low while for signals at 1.6 THz and 2.5 THz the junction is cooled to 6 K.Digital signal processing(DSP)chips are made use of to build a data acquisition and processing system so that it can be compact,fast,and intelligent.With the completion of the relevant hardwares and softwares,the measurements are now automated.展开更多
文摘Nonlinear science research is a hot point in the world.It has deepened our cognition of determinism and randomicity,simplicity and com-plexity,noise and order and it will profoundly influ-ence the progress of the study of natural science,including life science.Life is the most complex nonlinear system and heart is the core of lifecycle system.In the late more than 20 years,nonlinear research on heart electric activities has made much headway.The commonly used parameters are based on chaos and fractal theory,such as correlation dimension,Lyapunov ex-ponent,Kolmogorov entropy and multifractal singu-larity spectrum.This paper summarizes the commonly used methods in the nonlinear study of heart electric signal.Then,considering the shortages of the above tradi-tional nonlinear parameters,we mainly introduce the results on short-term heart rate variability(HRV)signal(500 R-R intervals)and HFECG signal(1-2s).Finally,we point out it is worthwhile to put emphasis on the study of the sensitive nonlinearity parameters of short-term heart electric signal and their dynamic character and clinical effectivity.
基金supported by the National Natural Science Foundation of China(Grant No.10874074)in part by the National Basic Research Program of China(Grant Nos.2006CB601006 and 2007CB310404)National High-tech R&D Program of China(Grant No.2006AA03Z214)
文摘Using YBa2Cu3O7-δ/MgO bicrystal Josephson junction,we have developed a setup for spectrum analyses of terahertz signals,up to 2.5 THz,with a frequency resolution of 3 GHz.The junction works at liquid nitrogen temperature when the signal frequencies are low while for signals at 1.6 THz and 2.5 THz the junction is cooled to 6 K.Digital signal processing(DSP)chips are made use of to build a data acquisition and processing system so that it can be compact,fast,and intelligent.With the completion of the relevant hardwares and softwares,the measurements are now automated.
