在S im u link仿真环境下,采用层次化方法建立了中脉冲重复频率(M PRF)机载PD雷达数字仿真系统,给出了仿真的系统框图和仿真结果。对该机载PD雷达在不同情况下的检测性能和抗干扰能力进行分析。考虑干扰分别从雷达天线的旁瓣和主瓣进入...在S im u link仿真环境下,采用层次化方法建立了中脉冲重复频率(M PRF)机载PD雷达数字仿真系统,给出了仿真的系统框图和仿真结果。对该机载PD雷达在不同情况下的检测性能和抗干扰能力进行分析。考虑干扰分别从雷达天线的旁瓣和主瓣进入的情况,并采用自适应旁瓣相消技术后,得到了该雷达系统的检测概率曲线。仿真结果与理论计算结果相一致,从而正确地完成了系统的方案论证和性能评估,使雷达系统的设计更加方便、高效和优化。展开更多
The China Spallation Neutron Source(CSNS)is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW a...The China Spallation Neutron Source(CSNS)is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW at a repetition rate of 25 Hz.In this paper,we focus on the physical design of CSNS target station and neutron instruments.Under optimized design,the flat tungsten target and the compact target-moderator-reflector coupling enhance effective cold and thermal neutron output from moderators.Three wing-type moderators supply four different characteristics of neutrons to 19 beamlines primarily for neutron scattering applications.Layout of neutron instruments are conceptually planned for total 20 beamlines,the configuration and specification have been determined for three day-one neutron instruments.All designs are optimized for the Phase I of 100 kW with a upgradable capacity to 500 kW.展开更多
As a novel one-atom-thick carbon allotrope,graphdiyne(GDY)has attracted wide interest in two-dimensional materials owing to its unique feature with a planar layer comprising sp2-and sp-hybridized carbon atoms and a di...As a novel one-atom-thick carbon allotrope,graphdiyne(GDY)has attracted wide interest in two-dimensional materials owing to its unique feature with a planar layer comprising sp2-and sp-hybridized carbon atoms and a direct natural bandgap.A high-quality saturable absorber(SA)based on GDY was successfully fabricated,and the nonlinear saturable absorption properties were investigated.A compact diode-pumped solid-state passively Q-switched laser based on the as-prepared GDY-SA could be operated at 2µm.The Q-switched laser delivered a maximum average output power of 1.29 W at a central wavelength of 1908.41 nm with up to 54.8%slope efficiency.A repetition rate of 91.58 kHz and single pulse energy of 23.08µJ were obtained.This work is the first application of GDY as an SA to generate all-solid-state pulsed lasers.These results indicate that GDY is a promising SA for solid-state pulsed lasers and has further application potential for ultrafast photonic devices in the 2-µm region.展开更多
文摘在S im u link仿真环境下,采用层次化方法建立了中脉冲重复频率(M PRF)机载PD雷达数字仿真系统,给出了仿真的系统框图和仿真结果。对该机载PD雷达在不同情况下的检测性能和抗干扰能力进行分析。考虑干扰分别从雷达天线的旁瓣和主瓣进入的情况,并采用自适应旁瓣相消技术后,得到了该雷达系统的检测概率曲线。仿真结果与理论计算结果相一致,从而正确地完成了系统的方案论证和性能评估,使雷达系统的设计更加方便、高效和优化。
基金supported by the National Large Facility Project from the National Development and Reform Commissionthe CSNS R&D funds from CAS,Guangdong Province,and Dongguan Citythe National Basic Research Program of China(Grant No.2010CB833102)
文摘The China Spallation Neutron Source(CSNS)is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW at a repetition rate of 25 Hz.In this paper,we focus on the physical design of CSNS target station and neutron instruments.Under optimized design,the flat tungsten target and the compact target-moderator-reflector coupling enhance effective cold and thermal neutron output from moderators.Three wing-type moderators supply four different characteristics of neutrons to 19 beamlines primarily for neutron scattering applications.Layout of neutron instruments are conceptually planned for total 20 beamlines,the configuration and specification have been determined for three day-one neutron instruments.All designs are optimized for the Phase I of 100 kW with a upgradable capacity to 500 kW.
基金financially supported by the National Natural Science Foundation of China (11974220, 61635012,61875138, 61961136001, and U1801254)the State Key Research Development Program of China (2019YFB2203503)
文摘As a novel one-atom-thick carbon allotrope,graphdiyne(GDY)has attracted wide interest in two-dimensional materials owing to its unique feature with a planar layer comprising sp2-and sp-hybridized carbon atoms and a direct natural bandgap.A high-quality saturable absorber(SA)based on GDY was successfully fabricated,and the nonlinear saturable absorption properties were investigated.A compact diode-pumped solid-state passively Q-switched laser based on the as-prepared GDY-SA could be operated at 2µm.The Q-switched laser delivered a maximum average output power of 1.29 W at a central wavelength of 1908.41 nm with up to 54.8%slope efficiency.A repetition rate of 91.58 kHz and single pulse energy of 23.08µJ were obtained.This work is the first application of GDY as an SA to generate all-solid-state pulsed lasers.These results indicate that GDY is a promising SA for solid-state pulsed lasers and has further application potential for ultrafast photonic devices in the 2-µm region.
