Simultaneous production of high-frequency synthetic apomixis with high fertility and improved agronomic traits in hybrid rice

Dear Editor,Utilization of heterosis is fundamental to modern agricultural improvement and contributes significantly to food security and agricultural development(Ouyang et al.,2022).However,heterosis of F,hybrids cannot be stably inherited.Apomixis,or asexual reproduction through seeds,offers the potential for the fixation of heterosis in F,hybrids and the formation of clonal offspring,which could have considerable implications for plant breeding and agriculture(Schmidt,2020).But naturally occurring apomixis has never been found in major crops.Recently,synthetic apomixis has been successfully generated by inducing incomplete meiotic development combined with parthenogenesis development to produce cloned rice(Oryza sativa)seeds(Khanday et al.,2019;Wang et al.,2019;Vernet et al.,2022;Wei et al.,2023).

Simulation research on cable-laying scheme of HIAF dipole power supply

Background A strong electromagnetic force is the major cause of vibration in dipole power supply cables.Moreover,the long-term operation of cables under vibration conditions leads to structural fatigue failure.Purpose and methods To investigate the cable-laying scheme of a dipole power supply,a finite element model for the electromagnetic–structural coupling between cables and cleats was established.The electrodynamic forces were simulated for fixed-length cables in the horizontal,vertical,and bent models under pulse-current excitation.Subsequently,based on the optimized arrangement mode,the deformation of the cables and the stresses of the cleats were obtained.Results A small cable electrodynamic force was observed in the positive–negative interlace arrangement,and the cable deformation was caused by electrodynamic forces.The maximum cleat deformation occurred at the position with the largest electrodynamic force,where the cleats were reinforced.Moreover,the mechanical characteristics of the cables and cleats under pulse-current excitation are described intuitively and quantitatively,providing theoretical support for the cable-laying scheme of the dipole power supply.

The bipolar kicker power supply principle prototype for the booster ring of HIAF

Background The kicker power supply is one of the key devices to achieve fast extraction for the booster ring(BRing)of high intensity heavy ion accelerator facility.For the expected high beam intensity in the BRing,a beam dump is requested for an emergency case.Therefore,a bipolar kicker power supply is required to extract bunched beams to the regular beamline and the beam dump.Purpose The purpose of this paper is to design and test a bipolar kicker power supply principle prototype.Methods For this purpose,a solid-state Marx generator circuit based on pulse forming network with insulated gate bipolar transistors is applied to the bipolar kicker power supply principle prototype.Results The experimental results show that the principle prototype has the ability to produce a bipolar extraction current,and the polarity can be arbitrarily selected.Besides,a flat-top duration of the extraction current adjusting from 0 to 1.23μs has been accomplished.Conclusions The output performance of the principle prototype satisfies the design requirements and verifies the feasibility of the design.