A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 1...A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 125 nm ultraviolet pulse to the orthogonal two-color field, not only the harmonic yield is enhanced by 2 orders of magnitude compared with the original orthogonal two-color field case, but also the single short quantum path, which is selected to contribute to the harmonic spectrum, results in an ultrabroad 152 eV bandwidth. Moreover, by optimizing the laser parameters, we find that the harmonic enhancement is not very sen- sitive to the pulse duration and the polarized angle of the assisted ultraviolet pulse, which is much better for experimental realization. As a result, an isolated pulse with duration of 38 as can be obtained, which is 2 orders of magnitude improvement in comparison with the original two-color orthogonal field case.展开更多
Analysis is given to energy sources home and abroad, the employed and customer market in oceanographic engineering and necessity of its development. Risk out of system is put forward just after marine industry into oc...Analysis is given to energy sources home and abroad, the employed and customer market in oceanographic engineering and necessity of its development. Risk out of system is put forward just after marine industry into oceanographic engineering market. It also metions several influencing factors including politics, finance and ocean engineering materials.展开更多
China, as a power in ecotourism resources, is luxuriant in eco-tourism resources. With the continuous expansion of the ecological tourism market, however, the ecological tourism environment protection problems are bec...China, as a power in ecotourism resources, is luxuriant in eco-tourism resources. With the continuous expansion of the ecological tourism market, however, the ecological tourism environment protection problems are becoming acute. Then, the ecological tourism will be in a fatal blow in China if the ecological tourism environment is not being protected. Therefore, improving China＇ s ecological tourism environmental protection legal system is of important practical significance to the sustainable development of tourism on the basis of introducing the experience of developed countries in ecotourism environmental protection act.展开更多
An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicin...An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicinity of metallic nanostructures. The results show that by properly choosing the inhomogeneity of the two-color multi-cycle(20 fs) weak pulse(1013W/cm2), not only the harmonic cutoff has been extended, resulting in a broadband XUV continuum, but also the single short quantum path has been selected to contribute to the harmonic. As a result, two isolated XUV pulses with durations of 68 as and 66 as can be obtained.展开更多
基金supported by the National Natural Science Foundation of China (12025303, 11890693)the National Key R&D Program of China (2022YFF0503401)+1 种基金the K.C.Wong Education Foundationthe China Manned S pace Project (CMS-CSST-2021-A06)
文摘A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 125 nm ultraviolet pulse to the orthogonal two-color field, not only the harmonic yield is enhanced by 2 orders of magnitude compared with the original orthogonal two-color field case, but also the single short quantum path, which is selected to contribute to the harmonic spectrum, results in an ultrabroad 152 eV bandwidth. Moreover, by optimizing the laser parameters, we find that the harmonic enhancement is not very sen- sitive to the pulse duration and the polarized angle of the assisted ultraviolet pulse, which is much better for experimental realization. As a result, an isolated pulse with duration of 38 as can be obtained, which is 2 orders of magnitude improvement in comparison with the original two-color orthogonal field case.
文摘Analysis is given to energy sources home and abroad, the employed and customer market in oceanographic engineering and necessity of its development. Risk out of system is put forward just after marine industry into oceanographic engineering market. It also metions several influencing factors including politics, finance and ocean engineering materials.
文摘China, as a power in ecotourism resources, is luxuriant in eco-tourism resources. With the continuous expansion of the ecological tourism market, however, the ecological tourism environment protection problems are becoming acute. Then, the ecological tourism will be in a fatal blow in China if the ecological tourism environment is not being protected. Therefore, improving China＇ s ecological tourism environmental protection legal system is of important practical significance to the sustainable development of tourism on the basis of introducing the experience of developed countries in ecotourism environmental protection act.
基金Supported by the Scientific Research Fund of Liaoning University of Technology of China under Grant No.X201319the Scientific Research Fund of Liaoning Provincial Education Department under Grant No.L2014242
文摘An efficient method for attosecond extreme ultraviolet source generation under the two-color multi-cycle weak pulse has been theoretically presented by using the concept of the plasmonic field enhancement in the vicinity of metallic nanostructures. The results show that by properly choosing the inhomogeneity of the two-color multi-cycle(20 fs) weak pulse(1013W/cm2), not only the harmonic cutoff has been extended, resulting in a broadband XUV continuum, but also the single short quantum path has been selected to contribute to the harmonic. As a result, two isolated XUV pulses with durations of 68 as and 66 as can be obtained.
