The parameter dependence of transition between electrostatic instabilities is studied using gyrokinetic simulation based on a real discharge of steady-state scenario in the Experimental Advanced Superconducting Tokama...The parameter dependence of transition between electrostatic instabilities is studied using gyrokinetic simulation based on a real discharge of steady-state scenario in the Experimental Advanced Superconducting Tokamak.The scan of radial locations shows that trapped electron mode(TEM)dominates around the core while the ion temperature gradient mode(ITG)simultaneously dominates outside.The maximum growth rate of TEM appears aroundρ=0.24,where the maximum electron temperature gradient R/LTelocates,ρis the normalized poloidal flux.Effects of the parameters on the transition between TEM and ITG instability are studied atρ=0.24.It is found that TEM dominates in the scanning with individually changing R/LTe from 2.50 to 25.02 or the density gradient R/L_(n)from 1.38 to 13.76.Meanwhile,the electron-ion temperature ratio T_(e)/T_(i)is found to destabilize TEM,the effect of Teis more sensitive than that of T_(i).The dominant instability diagrams in the(R/L_(Te),R/L_(Ti))plane at different T_(e)/T_(i)and R/Lnare numerically obtained,which clearly show the parameter range of the dominant TEM or dominant ITG instability region.It is found that the dominant TEM region becomes narrower in the plane by decreasing R/L_(n)when T_(e)/T_(i)>0.5.展开更多
Escherichia coli strain K-12 MG1655 has been proposed as an appropriate host strain for industrial production.However,the direct application of this strain suffers from the transformation inefficiency and plasmid inst...Escherichia coli strain K-12 MG1655 has been proposed as an appropriate host strain for industrial production.However,the direct application of this strain suffers from the transformation inefficiency and plasmid instability.Herein,we conducted genetic modifications at a serial of loci of MG1655 genome,generating a robust and universal host strain JW128 with higher transformation efficiency and plasmid stability that can be used to efficiently produce desired chemicals after introducing the corresponding synthetic pathways.Using JW128 as the host,the titer of isobutanol reached 5.76 g/L in shake-flask fermentation,and the titer of lycopene reached 1.91 g/L in test-tube fermentation,40-fold and 5-fold higher than that of original MG1655,respectively.These results demonstrated JW128 is a promising chassis for high-level production of value-added chemicals.展开更多
基金supported by the National MCF Energy R&D Program of China(Nos.2019YFE03060000,2019YFE03050000 and 2019YFE03020004)National Natural Science Foundation of China(Nos.12005063 and 11875131)+1 种基金Users with Excellence Program of Hefei Science Center CAS(Nos.2020HSC-UE011 and 2021HSC-UE015)Anhui Provincial Natural Science Foundation(No.2008085Jo4)。
文摘The parameter dependence of transition between electrostatic instabilities is studied using gyrokinetic simulation based on a real discharge of steady-state scenario in the Experimental Advanced Superconducting Tokamak.The scan of radial locations shows that trapped electron mode(TEM)dominates around the core while the ion temperature gradient mode(ITG)simultaneously dominates outside.The maximum growth rate of TEM appears aroundρ=0.24,where the maximum electron temperature gradient R/LTelocates,ρis the normalized poloidal flux.Effects of the parameters on the transition between TEM and ITG instability are studied atρ=0.24.It is found that TEM dominates in the scanning with individually changing R/LTe from 2.50 to 25.02 or the density gradient R/L_(n)from 1.38 to 13.76.Meanwhile,the electron-ion temperature ratio T_(e)/T_(i)is found to destabilize TEM,the effect of Teis more sensitive than that of T_(i).The dominant instability diagrams in the(R/L_(Te),R/L_(Ti))plane at different T_(e)/T_(i)and R/Lnare numerically obtained,which clearly show the parameter range of the dominant TEM or dominant ITG instability region.It is found that the dominant TEM region becomes narrower in the plane by decreasing R/L_(n)when T_(e)/T_(i)>0.5.
基金The work finished in Beijing Institute of Technology was supported by the National Key R&D Program of China(grant No.2019YFA0904104)the National Natural Science Foundation of China(Grant No.21676026)the Fundamental Research Funds for the Central Universities.
文摘Escherichia coli strain K-12 MG1655 has been proposed as an appropriate host strain for industrial production.However,the direct application of this strain suffers from the transformation inefficiency and plasmid instability.Herein,we conducted genetic modifications at a serial of loci of MG1655 genome,generating a robust and universal host strain JW128 with higher transformation efficiency and plasmid stability that can be used to efficiently produce desired chemicals after introducing the corresponding synthetic pathways.Using JW128 as the host,the titer of isobutanol reached 5.76 g/L in shake-flask fermentation,and the titer of lycopene reached 1.91 g/L in test-tube fermentation,40-fold and 5-fold higher than that of original MG1655,respectively.These results demonstrated JW128 is a promising chassis for high-level production of value-added chemicals.
