The topological properties of the spatial coherence function are investigated rigorously. The phase singular structures （coherence vortices） of coherence function can be naturally deduced from the topological curren...The topological properties of the spatial coherence function are investigated rigorously. The phase singular structures （coherence vortices） of coherence function can be naturally deduced from the topological current, which is an abstract mathematical object studied previously. We find that coherence vortices are characterized by the Hopf index and Brouwer degree in topology. The coherence flux quantization and the linking of the closed coherence vortices are also studied from the topological properties of the spatial coherence function.展开更多
In this paper, the variational method combined with Green's function is used to analyze the characteristics of suspended, stripline. The result is in good agreement with references. The design of mm-wave end-coupl...In this paper, the variational method combined with Green's function is used to analyze the characteristics of suspended, stripline. The result is in good agreement with references. The design of mm-wave end-coupled bandpass filter with suspended substrate is discussed. The computer programs for design of suspended stripline and bandpass filter are established.展开更多
The Camassa-Holm-Kadomtsev-Petviashvili-I equation(CH-KP-I)is a two dimensional generalization of the Camassa-Holm equation(CH).In this paper,we prove transverse instability of the line solitary waves under periodic t...The Camassa-Holm-Kadomtsev-Petviashvili-I equation(CH-KP-I)is a two dimensional generalization of the Camassa-Holm equation(CH).In this paper,we prove transverse instability of the line solitary waves under periodic transverse perturbations.The proof is based on the framework of[18].Due to the high nonlinearity,our proof requires necessary modification.Specifically,we first establish the linear instability of the line solitary waves.Then through an approximation procedure,we prove that the linear effect actually dominates the nonlinear behavior.展开更多
based on optimal design on the core element of the sensor,a wireless and passive surface acoustic wave（SAW）temperature sensor integrated with ID Tag was presented.A reflective delay line,which consists of a transduc...based on optimal design on the core element of the sensor,a wireless and passive surface acoustic wave（SAW）temperature sensor integrated with ID Tag was presented.A reflective delay line,which consists of a transducer and eight reflectors on YZ LiNbO3 substrate.Was fabricated as the sensor element,in which,three reflectors were used for temperature sensing,and the other five were for the ID Tag using phase encoding.Single phase unidirectional transducers（SPUDTs）and shorted grating were used to structure the sAW device,leading to excellent signal to noise ratio（SNR）.The performance of the SAW device was simulated by the coupling of modes（COM）prior to fabrication.Using the network analyzer,the response in time domain of the fabricated 434 MHz SAW sensor was characterized,the measured S11 agrees well with the simulated one,sharp reflection peaks,high signal/noise,and low spurious noise between the reflection peaks were observed.Using the radar system based on FSCW as the reader unit.the developed SAW temperature sensors were evaluated wirelessly.Excellent1 inearity and good resolution of士1℃ were observed.展开更多
基金Support by the National Natural Science Foundation of China, and Cuiying Programme of Lanzhou University. The authors would like to thank Xin-Hui Zhang, Dong-Hui Xu, and Ran Li for helpful discussions.
文摘The topological properties of the spatial coherence function are investigated rigorously. The phase singular structures （coherence vortices） of coherence function can be naturally deduced from the topological current, which is an abstract mathematical object studied previously. We find that coherence vortices are characterized by the Hopf index and Brouwer degree in topology. The coherence flux quantization and the linking of the closed coherence vortices are also studied from the topological properties of the spatial coherence function.
文摘In this paper, the variational method combined with Green's function is used to analyze the characteristics of suspended, stripline. The result is in good agreement with references. The design of mm-wave end-coupled bandpass filter with suspended substrate is discussed. The computer programs for design of suspended stripline and bandpass filter are established.
基金supported in part by the NSF grants DMS-1907584.
文摘The Camassa-Holm-Kadomtsev-Petviashvili-I equation(CH-KP-I)is a two dimensional generalization of the Camassa-Holm equation(CH).In this paper,we prove transverse instability of the line solitary waves under periodic transverse perturbations.The proof is based on the framework of[18].Due to the high nonlinearity,our proof requires necessary modification.Specifically,we first establish the linear instability of the line solitary waves.Then through an approximation procedure,we prove that the linear effect actually dominates the nonlinear behavior.
基金supported by the National Nature Science Foundation of China(11074268,10834010)
文摘based on optimal design on the core element of the sensor,a wireless and passive surface acoustic wave（SAW）temperature sensor integrated with ID Tag was presented.A reflective delay line,which consists of a transducer and eight reflectors on YZ LiNbO3 substrate.Was fabricated as the sensor element,in which,three reflectors were used for temperature sensing,and the other five were for the ID Tag using phase encoding.Single phase unidirectional transducers（SPUDTs）and shorted grating were used to structure the sAW device,leading to excellent signal to noise ratio（SNR）.The performance of the SAW device was simulated by the coupling of modes（COM）prior to fabrication.Using the network analyzer,the response in time domain of the fabricated 434 MHz SAW sensor was characterized,the measured S11 agrees well with the simulated one,sharp reflection peaks,high signal/noise,and low spurious noise between the reflection peaks were observed.Using the radar system based on FSCW as the reader unit.the developed SAW temperature sensors were evaluated wirelessly.Excellent1 inearity and good resolution of士1℃ were observed.
