Tree peony belongs to one of the Saxifragales families,Paeoniaceae.It is one of the most famous ornamental plants,and is also a promising woody oil plant.Although two Paeoniaceae genomes have been released,their assem...Tree peony belongs to one of the Saxifragales families,Paeoniaceae.It is one of the most famous ornamental plants,and is also a promising woody oil plant.Although two Paeoniaceae genomes have been released,their assembly qualities are still to be improved.Additionally,more genomes from wild peonies are needed to accelerate genomic-assisted breeding.Here we assemble a high-quality and chromosome-scale 10.3-Gb genome of a wild Tibetan tree peony,Paeonia ludlowii,which features substantial sequence divergence,including around 75%specific sequences and gene-level differentials compared with other peony genomes.Our phylogenetic analyses suggest that Saxifragales and Vitales are sister taxa and,together with rosids,they are the sister taxon to asterids.The P.ludlowii genome is characterized by frequent chromosome reductions,centromere rearrangements,broadly distributed heterochromatin,and recent continuous bursts of transposable element(TE)movement in peony,although it lacks recent whole-genome duplication.These recent TE bursts appeared during the uplift and glacial period of the Qinghai-Tibet Plateau,perhaps contributing to adaptation to rapid climate changes.Further integrated analyses with methylome data revealed that genome expansion in peony might be dynamically affected by complex interactions among TE proliferation,TE removal,and DNA methylation silencing.Such interactions also impact numerous recently duplicated genes,particularly those related to oil biosynthesis and flower traits.This genome resource will not only provide the genomic basis for tree peony breeding but also shed light on the study of the evolution of huge genome structures as well as their protein-coding genes.展开更多
Separated Function RFQ (SFRFQ) was proposed as a post accelerator of RFQ to accelerate heavy ions at low frequency. It introduces gap accelerating in the quadrupole electrodes, and therefore it has higher accelerating...Separated Function RFQ (SFRFQ) was proposed as a post accelerator of RFQ to accelerate heavy ions at low frequency. It introduces gap accelerating in the quadrupole electrodes, and therefore it has higher accelerating efficiency than the conventional RFQ accelerator. The first SFRFQ prototype cavity has been specially designed and constructed as a post accelerator to accelerate O+ beam from 1.03 MeV to 1.64 MeV. Based on accomplishment of low power measurement and high power test, the beam commissioning was carried out to verify its feasibility. The measured energy gain per cell of SFRFQ is 45 keV, which is about 60% higher than that of Peking University Integral Split Ring (ISR) RFQ.展开更多
A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the elect...A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the electrodes is not flat. The resonant frequency needs to be tuned to the operating value. And the frequency needs to be compensated for temperature change during high power RF test and beam test. As tuning such a RFQ is difficult, plate tuners and stick tuners are designed. This paper will present the tuners design, the tuning procedure, and the RF properties of the RFQ.展开更多
基金This project was supported by grants from the National Natural Science Foundation of China(No.32270685)the Tibet Economic Forest Seedling Cultivation Project(202375)the local Science and Technology innovation projects of the central government(XZ202301YD0037C).We thank the high-performance computing platform at the National Key Laboratory of Crop Genetic Improvement at Huazhong Agricultural University.
文摘Tree peony belongs to one of the Saxifragales families,Paeoniaceae.It is one of the most famous ornamental plants,and is also a promising woody oil plant.Although two Paeoniaceae genomes have been released,their assembly qualities are still to be improved.Additionally,more genomes from wild peonies are needed to accelerate genomic-assisted breeding.Here we assemble a high-quality and chromosome-scale 10.3-Gb genome of a wild Tibetan tree peony,Paeonia ludlowii,which features substantial sequence divergence,including around 75%specific sequences and gene-level differentials compared with other peony genomes.Our phylogenetic analyses suggest that Saxifragales and Vitales are sister taxa and,together with rosids,they are the sister taxon to asterids.The P.ludlowii genome is characterized by frequent chromosome reductions,centromere rearrangements,broadly distributed heterochromatin,and recent continuous bursts of transposable element(TE)movement in peony,although it lacks recent whole-genome duplication.These recent TE bursts appeared during the uplift and glacial period of the Qinghai-Tibet Plateau,perhaps contributing to adaptation to rapid climate changes.Further integrated analyses with methylome data revealed that genome expansion in peony might be dynamically affected by complex interactions among TE proliferation,TE removal,and DNA methylation silencing.Such interactions also impact numerous recently duplicated genes,particularly those related to oil biosynthesis and flower traits.This genome resource will not only provide the genomic basis for tree peony breeding but also shed light on the study of the evolution of huge genome structures as well as their protein-coding genes.
基金supported by the National Natural Science Foundation of China (Grand No. 10905003)China Postdoctoral Science Foundation
文摘Separated Function RFQ (SFRFQ) was proposed as a post accelerator of RFQ to accelerate heavy ions at low frequency. It introduces gap accelerating in the quadrupole electrodes, and therefore it has higher accelerating efficiency than the conventional RFQ accelerator. The first SFRFQ prototype cavity has been specially designed and constructed as a post accelerator to accelerate O+ beam from 1.03 MeV to 1.64 MeV. Based on accomplishment of low power measurement and high power test, the beam commissioning was carried out to verify its feasibility. The measured energy gain per cell of SFRFQ is 45 keV, which is about 60% higher than that of Peking University Integral Split Ring (ISR) RFQ.
基金supported by the National Natural Science Foundation of China (Grant No. 107035020)the National Basic Research Program of China (Grant No. 2010CB833106)
文摘A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the electrodes is not flat. The resonant frequency needs to be tuned to the operating value. And the frequency needs to be compensated for temperature change during high power RF test and beam test. As tuning such a RFQ is difficult, plate tuners and stick tuners are designed. This paper will present the tuners design, the tuning procedure, and the RF properties of the RFQ.
