The existing methods for extracting the arrival time and amplitude of ultrasonic echo cannot eff ectively avoid the local interference of ultrasonic signals while drilling,which leads to poor accuracy of the echo arri...The existing methods for extracting the arrival time and amplitude of ultrasonic echo cannot eff ectively avoid the local interference of ultrasonic signals while drilling,which leads to poor accuracy of the echo arrival time and amplitude extracted by an ultrasonic imaging logging-while-drilling tool.In this study,a demodulation algorithm is used to preprocess the ultrasonic simulation signals while drilling,and we design a backpropagation neural network model to fit the relationship between the waveform data and time and amplitude.An ultrasonic imaging logging model is established,and the finite element simulation software is used for forward modeling.The response under diff erent measurement conditions is simulated by changing the model parameters,which are used as the input layer of the neural network model;The ultrasonic echo signal is considered as a low-frequency signal modulated by a high-frequency carrier signal,and a low-pass fi lter is designed to remove the high-frequency signal and obtain the low-frequency envelope signal.Then the amplitude of the envelope signal and its corresponding time are extracted as an output layer of the neural network model.By comparing the application eff ects of the various training methods,we fi nd that the conjugate gradient descent method is the most suitable method for solving the neural network model.The performance of the neural network model is tested using 11 groups of simulation test data,which verify the eff ectiveness of the model and lay the foundation for further practical application.展开更多
Medical ultrasound contrast imaging is a powerful modality undergoing successive developments in the last decade to date Lately, pulse inversion has been used in both ultrasound tissue harmonic and contrast imaging. H...Medical ultrasound contrast imaging is a powerful modality undergoing successive developments in the last decade to date Lately, pulse inversion has been used in both ultrasound tissue harmonic and contrast imaging. However, there was a tradeoff between resolution and penetration. Chirp excitations partially solved the tradeoff, but the chirp setting parameters were not optimized. The present work proposes for the first time combining chirp inversion with ultrasound contrast imaging, with the motivation to improve the contrast, by automatically optimizing the setting parameters of chirp excitation, it is thus an optimal command problem. Linear chirps, 5 μm diameter microbubbles and gradient ascent algorithm were simulated to optimize the chirp setting parameters. Simulations exhibited a gain of 5 dB by automatic optimization of chirp inversion relative to pulse inversion. The automatic optimization process was quite fast. Combining chirp inversion with ultrasound contrast imaging led to a maximum backscattered power permitting high contrast outcomes and optimum parameters.展开更多
The self-assembled phospholipid-or cytosolassociated multienzyme complexes constitute necessary components of the foundation of life.As a proof of concept,metalcoordinated supramolecular nanogels (MCSGs) have been des...The self-assembled phospholipid-or cytosolassociated multienzyme complexes constitute necessary components of the foundation of life.As a proof of concept,metalcoordinated supramolecular nanogels (MCSGs) have been designed,with the self-assembly of di-lysine coordinated iron(Fe(Lys)_(2))-functionalized peptide gelators on the interface by an in situ amidation-induced protonation process.The monoatomic and highly dispersed active centers of Fe(Lys)_(2) offered the nanogel mimics with excellent reaction rates due to the high density and nano compartmental structure similar to the natural matrix-associated multienzyme complex.SiO_(2)@MCSGs show both superoxide dismutase (SOD) activity and peroxidase (POD) activity,and the higher activities compared with the activity of free Fe(Lys);molecules can be detected.After loading the substrate 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS),SiO_(2)@MCSGs;can responsively convert O^(-)_(2) in the tumor microenvironment into H_(2)O_(2) intermediates and then tandem catalyze the oxidization of ABTS for contrast photoacoustic (PA) imaging of tumor by the SOD-POD mimic activity,showing their great potential as the efficient enzymatic agents for pathological theranostics.展开更多
基金funded by the Sinopec Engineering Technology Research InstituteThe name of the project is the Research and Development of Drilling Wall Ultrasonic Imaging System(No.PE19011-1)。
文摘The existing methods for extracting the arrival time and amplitude of ultrasonic echo cannot eff ectively avoid the local interference of ultrasonic signals while drilling,which leads to poor accuracy of the echo arrival time and amplitude extracted by an ultrasonic imaging logging-while-drilling tool.In this study,a demodulation algorithm is used to preprocess the ultrasonic simulation signals while drilling,and we design a backpropagation neural network model to fit the relationship between the waveform data and time and amplitude.An ultrasonic imaging logging model is established,and the finite element simulation software is used for forward modeling.The response under diff erent measurement conditions is simulated by changing the model parameters,which are used as the input layer of the neural network model;The ultrasonic echo signal is considered as a low-frequency signal modulated by a high-frequency carrier signal,and a low-pass fi lter is designed to remove the high-frequency signal and obtain the low-frequency envelope signal.Then the amplitude of the envelope signal and its corresponding time are extracted as an output layer of the neural network model.By comparing the application eff ects of the various training methods,we fi nd that the conjugate gradient descent method is the most suitable method for solving the neural network model.The performance of the neural network model is tested using 11 groups of simulation test data,which verify the eff ectiveness of the model and lay the foundation for further practical application.
文摘Medical ultrasound contrast imaging is a powerful modality undergoing successive developments in the last decade to date Lately, pulse inversion has been used in both ultrasound tissue harmonic and contrast imaging. However, there was a tradeoff between resolution and penetration. Chirp excitations partially solved the tradeoff, but the chirp setting parameters were not optimized. The present work proposes for the first time combining chirp inversion with ultrasound contrast imaging, with the motivation to improve the contrast, by automatically optimizing the setting parameters of chirp excitation, it is thus an optimal command problem. Linear chirps, 5 μm diameter microbubbles and gradient ascent algorithm were simulated to optimize the chirp setting parameters. Simulations exhibited a gain of 5 dB by automatic optimization of chirp inversion relative to pulse inversion. The automatic optimization process was quite fast. Combining chirp inversion with ultrasound contrast imaging led to a maximum backscattered power permitting high contrast outcomes and optimum parameters.
基金supported by the National Natural Science Foundation of China (51773155 and 51873156)the National Key Research and Development Program (2016YFA0100800 and 2018YFC1803100)。
文摘The self-assembled phospholipid-or cytosolassociated multienzyme complexes constitute necessary components of the foundation of life.As a proof of concept,metalcoordinated supramolecular nanogels (MCSGs) have been designed,with the self-assembly of di-lysine coordinated iron(Fe(Lys)_(2))-functionalized peptide gelators on the interface by an in situ amidation-induced protonation process.The monoatomic and highly dispersed active centers of Fe(Lys)_(2) offered the nanogel mimics with excellent reaction rates due to the high density and nano compartmental structure similar to the natural matrix-associated multienzyme complex.SiO_(2)@MCSGs show both superoxide dismutase (SOD) activity and peroxidase (POD) activity,and the higher activities compared with the activity of free Fe(Lys);molecules can be detected.After loading the substrate 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS),SiO_(2)@MCSGs;can responsively convert O^(-)_(2) in the tumor microenvironment into H_(2)O_(2) intermediates and then tandem catalyze the oxidization of ABTS for contrast photoacoustic (PA) imaging of tumor by the SOD-POD mimic activity,showing their great potential as the efficient enzymatic agents for pathological theranostics.
