The basic principle that shoes would indicate its maximum value only when they are worn by people is exactly what people constantly ignore.How to find out the recipe toones own color matching?The key answer would be&q...The basic principle that shoes would indicate its maximum value only when they are worn by people is exactly what people constantly ignore.How to find out the recipe toones own color matching?The key answer would be"people oriented".展开更多
We study theoretically intense terahertz radiation from multi-color laser pulse with uncommon frequency ratios. Com- paring the two-color laser scheme, of which the uncommon frequency ratio should be set to be a speci...We study theoretically intense terahertz radiation from multi-color laser pulse with uncommon frequency ratios. Com- paring the two-color laser scheme, of which the uncommon frequency ratio should be set to be a specific value, we show that by using multi-color harmonic laser pulses as the first pump component, the lasers as the second pump component can be adjusted in a continuous frequency range. Moreover, these multi-color laser pulses can effectively modulate and enhance the terahertz radiation, and the terahertz yield increases with the increase of the wavelength of the uncommon pump com- ponent and is stable to the laser relative phase. Finally, we utilize the electron densities and velocities of ionization events to illustrate the physical mechanism of the intense terahertz generation.展开更多
Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theo...Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theoretically investigate the effect of the two-color laser wavelength on the terahertz generation in the air based on a transient photocurrent model.We show that the long wavelength laser excitation can greatly enhance the terahertz amplitude for a given total laser intensity. Furthermore, we utilize a local current model to illustrate the enhancement mechanism. Our analysis shows that the terahertz amplitude is determined by the superposition of contributions from individual ionization events, and for the long wavelength laser excitation, the electron production concentrates in a few ionization events and acquires the larger drift velocities, which results in the stronger terahertz radiation generation. These results will be very helpful for understanding the terahertz generation process and optimizing the terahertz output.展开更多
This paper proposes a negotiation-based TDMA scheme for ad hoc networks, which was modeled as an asynchronous myopic repeated game. Compared to the traditional centralized TDMA schemes, our scheme operates in a decent...This paper proposes a negotiation-based TDMA scheme for ad hoc networks, which was modeled as an asynchronous myopic repeated game. Compared to the traditional centralized TDMA schemes, our scheme operates in a decentralized manner and is scalable to topology changes. Simulation results show that, with respect to the coloring quality, the performance of our scheme is close to that of the classical centralized algorithms with much lower complexity.展开更多
文摘The basic principle that shoes would indicate its maximum value only when they are worn by people is exactly what people constantly ignore.How to find out the recipe toones own color matching?The key answer would be"people oriented".
基金Project supported by the National Natural Science Foundation of China(Grant No.11604205)the Talent Program of Shanghai University of Engineering Science,China
文摘We study theoretically intense terahertz radiation from multi-color laser pulse with uncommon frequency ratios. Com- paring the two-color laser scheme, of which the uncommon frequency ratio should be set to be a specific value, we show that by using multi-color harmonic laser pulses as the first pump component, the lasers as the second pump component can be adjusted in a continuous frequency range. Moreover, these multi-color laser pulses can effectively modulate and enhance the terahertz radiation, and the terahertz yield increases with the increase of the wavelength of the uncommon pump com- ponent and is stable to the laser relative phase. Finally, we utilize the electron densities and velocities of ionization events to illustrate the physical mechanism of the intense terahertz generation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51132004,11604205,and 11474096)Science and Technology Commission of Shanghai Municipality,China(Grant No.14JC1401500)+1 种基金Shanghai Municipal Education Commission,China(Grant No.ZZGCD15066)Foundation of Fujian Educational Committee,China(Grant No.JAT160412)
文摘Near-IR femtosecond lasers have been proposed to produce high-field terahertz radiation in the air via the laser-plasma interaction, but the physical mechanism still needs to be further explored. In this work, we theoretically investigate the effect of the two-color laser wavelength on the terahertz generation in the air based on a transient photocurrent model.We show that the long wavelength laser excitation can greatly enhance the terahertz amplitude for a given total laser intensity. Furthermore, we utilize a local current model to illustrate the enhancement mechanism. Our analysis shows that the terahertz amplitude is determined by the superposition of contributions from individual ionization events, and for the long wavelength laser excitation, the electron production concentrates in a few ionization events and acquires the larger drift velocities, which results in the stronger terahertz radiation generation. These results will be very helpful for understanding the terahertz generation process and optimizing the terahertz output.
基金supported in part by National Science Fund for Distinguished Young Scholars under Grant No.60725105National Key Basic Research Program of China ( 973 Program ) under Grant No.2009CB320404+2 种基金Program for Changjiang Scholars and Innovative Research Team in University under Grant No.IRT0852National Natural Science Foundation of China under Grants No.60972047, 61072068111 Project under Grant No.B08038
文摘This paper proposes a negotiation-based TDMA scheme for ad hoc networks, which was modeled as an asynchronous myopic repeated game. Compared to the traditional centralized TDMA schemes, our scheme operates in a decentralized manner and is scalable to topology changes. Simulation results show that, with respect to the coloring quality, the performance of our scheme is close to that of the classical centralized algorithms with much lower complexity.
