Objectives and Methods: Both the concentration and the size of contrast microbubbles are the important factors that affect the quality of intravenous myocardial contrast echocardiography (IVMCE) image, but the interac...Objectives and Methods: Both the concentration and the size of contrast microbubbles are the important factors that affect the quality of intravenous myocardial contrast echocardiography (IVMCE) image, but the interactions between microbubbles and ultrasound are poorly understood. In order to select optimal ultrasound exposure condition for IVMCE, the influences of ultrasound power, frequency and exposure time on sonicated microbubbles stability were evaluated by a 2 x 2 x 4 factorial analysis in the study. Results: It was found that the concentration of microbubbles was decreased when the ultrasound power increased or the exposure time of ultrasound prolonged (P < 0. 001). The frequency of ultrasound did not influence the concentration of the bubbles (P = 0. 061 ). The higher the power or the frequency and the longer the exposuretime, the smaller the mean size of the contrast bubbles (power, P = 0.004; frequency, P < 0.001); exposure time, P < 0. 00l ). The controlling factors of the condition did not interactively affect the concentration or the mean size of contrast mi- crobubbles. Conclusion: These findings could allow us to select ultrasound at lower frequency, lower ultrasound power and to reduce the exposure time bine of microbubbles to ultrasound for the improvement in the contrast effect in IVMCE.展开更多
On the basis of the characteristic parameters selected from the fault sonic signals of cracking hammer with artificial diamond,by means of with time series analysis and time domain statistics,three layer artificial n...On the basis of the characteristic parameters selected from the fault sonic signals of cracking hammer with artificial diamond,by means of with time series analysis and time domain statistics,three layer artificial neural network is trained by an improved BP algorithm.The results state that the fault sonic signals can be identified by trained network system precisely.展开更多
文摘Objectives and Methods: Both the concentration and the size of contrast microbubbles are the important factors that affect the quality of intravenous myocardial contrast echocardiography (IVMCE) image, but the interactions between microbubbles and ultrasound are poorly understood. In order to select optimal ultrasound exposure condition for IVMCE, the influences of ultrasound power, frequency and exposure time on sonicated microbubbles stability were evaluated by a 2 x 2 x 4 factorial analysis in the study. Results: It was found that the concentration of microbubbles was decreased when the ultrasound power increased or the exposure time of ultrasound prolonged (P < 0. 001). The frequency of ultrasound did not influence the concentration of the bubbles (P = 0. 061 ). The higher the power or the frequency and the longer the exposuretime, the smaller the mean size of the contrast bubbles (power, P = 0.004; frequency, P < 0.001); exposure time, P < 0. 00l ). The controlling factors of the condition did not interactively affect the concentration or the mean size of contrast mi- crobubbles. Conclusion: These findings could allow us to select ultrasound at lower frequency, lower ultrasound power and to reduce the exposure time bine of microbubbles to ultrasound for the improvement in the contrast effect in IVMCE.
文摘On the basis of the characteristic parameters selected from the fault sonic signals of cracking hammer with artificial diamond,by means of with time series analysis and time domain statistics,three layer artificial neural network is trained by an improved BP algorithm.The results state that the fault sonic signals can be identified by trained network system precisely.
