Endoscopic submucosal dissection (ESD) is an advanced therapeutic endoscopic technique,which allowsresection of larger superficial tumors in the esophagus,stomach,and colon.Precise diagnosis of the boundary between tu...Endoscopic submucosal dissection (ESD) is an advanced therapeutic endoscopic technique,which allowsresection of larger superficial tumors in the esophagus,stomach,and colon.Precise diagnosis of the boundary between tumor and the non-tumorous surrounding portion is especially important before starting ESD,because too much resection can potentially take more time and can induce a higher complication rate,while too little resection can result in a non-curative resection.The boundary diagnosis is often difficult for early gastric cancer,mainly because of the underlying condition of chronic gastritis.Due to recent developments in endoscopy,including magnified endoscopy and narrow band endoscopy,the boundary diagnosis is becoming easy and more accurate.We have also applied magnified endoscopy combined with narrow band imaging to fresh specimens immediately after resection using thetiling method and XY stage.展开更多
Because of the increasing demand for electrical energy,vibration energy harvesters(VEHs)that convert vibratory energy into electrical energy are a promising technology.In order to improve the efficiency of harvesting ...Because of the increasing demand for electrical energy,vibration energy harvesters(VEHs)that convert vibratory energy into electrical energy are a promising technology.In order to improve the efficiency of harvesting energy from environmental vibration,here we investigate a hybrid VEH.Unlike previous studies,this article analyzes the stochastic responses of the hybrid piezoelectric and electromagnetic energy harvesting system with viscoelastic material under narrow-band(colored)noise.Firstly,a mass-spring-damping system model coupled with piezoelectric and electromagnetic circuits under fundamental acceleration excitation is established,and analytical solutions to the dimensionless equations are derived.Then,the formula of the amplitude-frequency responses in the deterministic case and the first-order and secondorder steady-state moments of the amplitude in the stochastic case are obtained by using the multi-scales method.The amplitude-frequency analytical solutions are in good agreement with the numerical solutions obtained by the Monte Carlo method.Furthermore,the stochastic bifurcation diagram is plotted for the first-order steady-state moment of the amplitude with respect to the detuning frequency and viscoelastic parameter.Eventually,the influence of system parameters on mean-square electric voltage,mean-square electric current and mean output power is discussed.Results show that the electromechanical coupling coefficients,random excitation and viscoelastic parameter have a positive effect on the output power of the system.展开更多
文摘Endoscopic submucosal dissection (ESD) is an advanced therapeutic endoscopic technique,which allowsresection of larger superficial tumors in the esophagus,stomach,and colon.Precise diagnosis of the boundary between tumor and the non-tumorous surrounding portion is especially important before starting ESD,because too much resection can potentially take more time and can induce a higher complication rate,while too little resection can result in a non-curative resection.The boundary diagnosis is often difficult for early gastric cancer,mainly because of the underlying condition of chronic gastritis.Due to recent developments in endoscopy,including magnified endoscopy and narrow band endoscopy,the boundary diagnosis is becoming easy and more accurate.We have also applied magnified endoscopy combined with narrow band imaging to fresh specimens immediately after resection using thetiling method and XY stage.
基金the National Natural Science Foundation of China(Grant Nos.12002089 and 11902081)the Science and Technology Projects in Guangzhou(Grant Nos.202201010326 and 2023A04J1323)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515010833)。
文摘Because of the increasing demand for electrical energy,vibration energy harvesters(VEHs)that convert vibratory energy into electrical energy are a promising technology.In order to improve the efficiency of harvesting energy from environmental vibration,here we investigate a hybrid VEH.Unlike previous studies,this article analyzes the stochastic responses of the hybrid piezoelectric and electromagnetic energy harvesting system with viscoelastic material under narrow-band(colored)noise.Firstly,a mass-spring-damping system model coupled with piezoelectric and electromagnetic circuits under fundamental acceleration excitation is established,and analytical solutions to the dimensionless equations are derived.Then,the formula of the amplitude-frequency responses in the deterministic case and the first-order and secondorder steady-state moments of the amplitude in the stochastic case are obtained by using the multi-scales method.The amplitude-frequency analytical solutions are in good agreement with the numerical solutions obtained by the Monte Carlo method.Furthermore,the stochastic bifurcation diagram is plotted for the first-order steady-state moment of the amplitude with respect to the detuning frequency and viscoelastic parameter.Eventually,the influence of system parameters on mean-square electric voltage,mean-square electric current and mean output power is discussed.Results show that the electromechanical coupling coefficients,random excitation and viscoelastic parameter have a positive effect on the output power of the system.
