Protected fruit cultivation in China has developed very quickly from the early 1990s, and now it is an important branch in fruit cultivation. A brief review including fruit species, developing history, growing area, o...Protected fruit cultivation in China has developed very quickly from the early 1990s, and now it is an important branch in fruit cultivation. A brief review including fruit species, developing history, growing area, output, and distribution in the whole country is made in the paper. Characteristics of the dominant kinds of greenhouse, environmental control methods, and standards of temperature, humidity, light and CO2 for different fruit species are presented. Information on varieties, growing benefits, special management practices and other aspects of the main fruit species used for protected cultivation are also presented.展开更多
Multi-lasers are proposed to enhance the proton acceleration in laser plasma interaction. A rear-holed target is illuminated by three lasers from different directions. The scheme is demonstrated by two-dimensional par...Multi-lasers are proposed to enhance the proton acceleration in laser plasma interaction. A rear-holed target is illuminated by three lasers from different directions. The scheme is demonstrated by two-dimensional particlein-cell simulations. The electron cloud shape is controlled well and the electron density is improved significantly. The electrons accelerated by the three lasers induce an enhanced target normal sheath acceleration(TNSA) which suppresses the proton beam divergence and improves the maximum proton energy. The maximum proton energy is 22.9 Me V, which increased significantly than that of a single-laser target interaction. Meanwhile, the average divergence angle(22.3?) is reduced. The dependence of the proton beam on the length of sidewall is investigated in detail and the optimal length is obtained.展开更多
文摘Protected fruit cultivation in China has developed very quickly from the early 1990s, and now it is an important branch in fruit cultivation. A brief review including fruit species, developing history, growing area, output, and distribution in the whole country is made in the paper. Characteristics of the dominant kinds of greenhouse, environmental control methods, and standards of temperature, humidity, light and CO2 for different fruit species are presented. Information on varieties, growing benefits, special management practices and other aspects of the main fruit species used for protected cultivation are also presented.
文摘Multi-lasers are proposed to enhance the proton acceleration in laser plasma interaction. A rear-holed target is illuminated by three lasers from different directions. The scheme is demonstrated by two-dimensional particlein-cell simulations. The electron cloud shape is controlled well and the electron density is improved significantly. The electrons accelerated by the three lasers induce an enhanced target normal sheath acceleration(TNSA) which suppresses the proton beam divergence and improves the maximum proton energy. The maximum proton energy is 22.9 Me V, which increased significantly than that of a single-laser target interaction. Meanwhile, the average divergence angle(22.3?) is reduced. The dependence of the proton beam on the length of sidewall is investigated in detail and the optimal length is obtained.
