Terahertz(THz) imaging is progressing as a robust platform for myriad applications in the field of security,health,and material science.The THz regime,which comprises wavelengths spanning from microns to millimeters,i...Terahertz(THz) imaging is progressing as a robust platform for myriad applications in the field of security,health,and material science.The THz regime,which comprises wavelengths spanning from microns to millimeters,is non-ionizing and has very low photon energy:Making it inherently safe for biological imaging.Colorectal cancer is one of the most common causes of death in the world,while the conventional screening and standard of care yet relies exclusively on the physician's experience.Researchers have been working on the development of a flexible THz endoscope,as a potential tool to aid in colorectal cancer screening.This involves building a single-channel THz endoscope,and profiling the THz response from colorectal tissue,and demonstrating endogenous contrast levels between normal and diseased tissue when imaging in reflection modality.The current level of contrast provided by the prototype THz endoscopic system represents a significant step towards clinical endoscopic application of THz technology for invivo colorectal cancer screening.The aim of this paper is to provide a short review of the recent advances in THz endoscopic technology and cancer imaging.In particular,the potential of single-channel THz endoscopic imaging for colonic cancer screening will be highlighted.展开更多
传统的信号检测方法在背景噪声较强的情况下一般会失效,混沌振子由于对初始值及参数具有敏感性从而可以很好地检测到微弱信号。首先简述了应用Van der Pol―Duffing振子和互相关方法检测微弱正弦信号的原理,然后应用二者联合的方法进行...传统的信号检测方法在背景噪声较强的情况下一般会失效,混沌振子由于对初始值及参数具有敏感性从而可以很好地检测到微弱信号。首先简述了应用Van der Pol―Duffing振子和互相关方法检测微弱正弦信号的原理,然后应用二者联合的方法进行微弱信号检测。该方法综合了互相关检测对噪声的抑制优势和Van der Pol―Duffing振子对微弱信号提取的优势。仿真实例表明,该方法能有效地检测出淹没在强噪声中的微弱正弦信号,且其信噪比门限比只用混沌振子方法更低,抗噪性更强。展开更多
研究了同时含有平方项和高次幂项的Van der Pol-Duffing系统的混沌行为及混沌控制问题,数值仿真分析了该系统存在的典型非线性动力学行为.主要采用单初始点分岔分析方法、最大Lyapunov指数和Poincare映射方法,从不同侧面揭示了在周期激...研究了同时含有平方项和高次幂项的Van der Pol-Duffing系统的混沌行为及混沌控制问题,数值仿真分析了该系统存在的典型非线性动力学行为.主要采用单初始点分岔分析方法、最大Lyapunov指数和Poincare映射方法,从不同侧面揭示了在周期激振力作用下系统的周期运动、混沌运动,以及运动形式的演化过程,并用x|x|控制方法实现了系统的混沌抑制问题.展开更多
文摘Terahertz(THz) imaging is progressing as a robust platform for myriad applications in the field of security,health,and material science.The THz regime,which comprises wavelengths spanning from microns to millimeters,is non-ionizing and has very low photon energy:Making it inherently safe for biological imaging.Colorectal cancer is one of the most common causes of death in the world,while the conventional screening and standard of care yet relies exclusively on the physician's experience.Researchers have been working on the development of a flexible THz endoscope,as a potential tool to aid in colorectal cancer screening.This involves building a single-channel THz endoscope,and profiling the THz response from colorectal tissue,and demonstrating endogenous contrast levels between normal and diseased tissue when imaging in reflection modality.The current level of contrast provided by the prototype THz endoscopic system represents a significant step towards clinical endoscopic application of THz technology for invivo colorectal cancer screening.The aim of this paper is to provide a short review of the recent advances in THz endoscopic technology and cancer imaging.In particular,the potential of single-channel THz endoscopic imaging for colonic cancer screening will be highlighted.
文摘传统的信号检测方法在背景噪声较强的情况下一般会失效,混沌振子由于对初始值及参数具有敏感性从而可以很好地检测到微弱信号。首先简述了应用Van der Pol―Duffing振子和互相关方法检测微弱正弦信号的原理,然后应用二者联合的方法进行微弱信号检测。该方法综合了互相关检测对噪声的抑制优势和Van der Pol―Duffing振子对微弱信号提取的优势。仿真实例表明,该方法能有效地检测出淹没在强噪声中的微弱正弦信号,且其信噪比门限比只用混沌振子方法更低,抗噪性更强。
文摘研究了同时含有平方项和高次幂项的Van der Pol-Duffing系统的混沌行为及混沌控制问题,数值仿真分析了该系统存在的典型非线性动力学行为.主要采用单初始点分岔分析方法、最大Lyapunov指数和Poincare映射方法,从不同侧面揭示了在周期激振力作用下系统的周期运动、混沌运动,以及运动形式的演化过程,并用x|x|控制方法实现了系统的混沌抑制问题.
