分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: The multi-bunch injection adopted at Shanghai Synchrotron Radiation Facility (SSRF) increases the injection rate greatly, with much less injection time than that of single bunch injection. It reduces massively the beam failure time during users operation and prolongs the pulsed injection hardware lifetime. In this paper, the scheme to produce multi bunches for the RF electron gun is described. The filling result and beam orbit stability for top up operation is discussed.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Simulating charged particle motion through the elements is necessary to understand modern particle accelerators. The particle numbers and the circling turns in a synchrotron are huge, and a simulation can be time-consuming. Open multi-processing (OpenMP) is a convenient method to speed up the computing of multi-cores for computers based on share memory model. Using message passing interface (MPI) which is based on non-uniform memory access architecture, a coarse grain parallel algorithm is set up for the Accelerator Toolbox (AT) for dynamic tracking processes. The computing speedup of the tracking process is 3.77 times with a quad-core CPU computer and the speed almost grows linearly with the number of CPU.
分类: 生物学 >> 生态学 提交时间: 2022-06-13 合作期刊: 《干旱区科学》
摘要: Abstract: Robinia pseudoacacia L. (RP) restoration has increased vegetation cover in semi-arid regions on the Loess Plateau of China, but ecological problems have also occurred due to RP restoration, such as reduced soil moisture. Further, it is still uncertain how microbial diversity, composition and assembly processes change with RP restoration in semi-arid regions. Therefore, amplicon sequencing of small subunit ribosomal ribonucleic acid (16S rRNA) and internal transcribed spacer (ITS) genes was performed to study soil bacterial and fungal diversity, composition and assembly processes at four study sites with different stand ages of RP plantations (Y10, RP plantation with stand ages less than 10 a; Y15, RP plantation with stand ages approximately 15 a; Y25, RP plantation with stand ages approximately 25 a; and Y40, RP plantation with stand ages approximately 40 a) along a 40-a chronosequence on the Loess Plateau. The diversity of soil bacteria and fungi increased significantly during the restoration period from 10 to 15 a (P