A new scheme is proposed to improve the electron beam quality of ionization-induced injection by tailoring gas profile in laser wakefield acceleration.Two-dimensional particle-in-cell simulations show that the ionizat...A new scheme is proposed to improve the electron beam quality of ionization-induced injection by tailoring gas profile in laser wakefield acceleration.Two-dimensional particle-in-cell simulations show that the ionization-induced injection mainly occurs in high-density stage and automatically truncates in low-density stage due to the decrease of the wakefield potential difference.The beam loading can be compensated by the elongated beam resulting from the density transition stage.The beam quality can be improved by shorter injection distance and beam loading effect.A quasi-monoenergetic electron beam with a central energy of 258 MeV and an energy spread of 5.1%is obtained under certain laser-plasma conditions.展开更多
The traditional Chinese martial arts are rooted in traditional Chinese culture, mature agricultural society, with a strong national character and the era in China＇ s. The role of capital, with the change of tradition...The traditional Chinese martial arts are rooted in traditional Chinese culture, mature agricultural society, with a strong national character and the era in China＇ s. The role of capital, with the change of traditional Chinese society, traditional Chinese martial arts rely on the economic base and social patterns are gradually changing. The contemporary historical context on the basis of the traditional martial arts of the depth of inspection, to explore the path of the contemporary development of the traditional martial arts. Studies suggest that the era of globalization and social transformation in China＇ s new historical context of the traditional martial arts with a series of problem domain, crack these problems, to seek new development path for the traditional martial arts.展开更多
XIAO Li is a worker with a textile factory and has been married four years. At the end of last year she got pregnant and was excited by the news she would soon become a mother. But she was not sure what insurance she ...XIAO Li is a worker with a textile factory and has been married four years. At the end of last year she got pregnant and was excited by the news she would soon become a mother. But she was not sure what insurance she could enjoy during her child-bearing period. She went to ask the person who is in charge of the women's section of her展开更多
According to international research only when the percentage of women with decision-making power reaches 30 percent can their effect on policy making be seen. In 1994, women accounted for an average of 5.7 percent of ...According to international research only when the percentage of women with decision-making power reaches 30 percent can their effect on policy making be seen. In 1994, women accounted for an average of 5.7 percent of state cabinet seats throughout the world. Authoritative thinking is that in the past decade almost no progress was made in realizing the展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12005297,11975308,and 11775305)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA25050200)+2 种基金the Fund of Science Challenge Project(Grant No.TZ2018001)Natural Science Foundation of Hunan Province,China(Grant No.2020JJ5651)the Fund of the State Key Laboratory of Laser Interaction with Matter(Grant No.SKLLIM1908)。
文摘A new scheme is proposed to improve the electron beam quality of ionization-induced injection by tailoring gas profile in laser wakefield acceleration.Two-dimensional particle-in-cell simulations show that the ionization-induced injection mainly occurs in high-density stage and automatically truncates in low-density stage due to the decrease of the wakefield potential difference.The beam loading can be compensated by the elongated beam resulting from the density transition stage.The beam quality can be improved by shorter injection distance and beam loading effect.A quasi-monoenergetic electron beam with a central energy of 258 MeV and an energy spread of 5.1%is obtained under certain laser-plasma conditions.
文摘The traditional Chinese martial arts are rooted in traditional Chinese culture, mature agricultural society, with a strong national character and the era in China＇ s. The role of capital, with the change of traditional Chinese society, traditional Chinese martial arts rely on the economic base and social patterns are gradually changing. The contemporary historical context on the basis of the traditional martial arts of the depth of inspection, to explore the path of the contemporary development of the traditional martial arts. Studies suggest that the era of globalization and social transformation in China＇ s new historical context of the traditional martial arts with a series of problem domain, crack these problems, to seek new development path for the traditional martial arts.
文摘XIAO Li is a worker with a textile factory and has been married four years. At the end of last year she got pregnant and was excited by the news she would soon become a mother. But she was not sure what insurance she could enjoy during her child-bearing period. She went to ask the person who is in charge of the women's section of her
文摘According to international research only when the percentage of women with decision-making power reaches 30 percent can their effect on policy making be seen. In 1994, women accounted for an average of 5.7 percent of state cabinet seats throughout the world. Authoritative thinking is that in the past decade almost no progress was made in realizing the
