Transition-metal nitrides exhibit wide potential windows and good electrochemical performance, but usually experience imbalanced practical applications in the energy storage field due to aggregation, poor circulation ...Transition-metal nitrides exhibit wide potential windows and good electrochemical performance, but usually experience imbalanced practical applications in the energy storage field due to aggregation, poor circulation stability, and complicated syntheses. In this study, a novel and simple multiphase polymeric strategy was developed to fabricate hybrid vanadium nitride/carbon(VN/C) membranes for supercapacitor negative electrodes, in which VN nanoparticles were uniformly distributed in the hierarchical porous carbon 3D networks. The supercapacitor negative electrode based on VN/C membranes exhibited a high specific capacitance of 392.0 F g^(-1) at 0.5 A g^(-1) and an excellent rate capability with capacitance retention of 50.5% at 30 A g^(-1). For the asymmetric device fabricated using Ni(OH)_2//VN/C membranes, a high energy density of 43.0 Wh kg^(-1) at a power density of800 W kg^(-1) was observed. Moreover, the device also showed good cycling stability of 82.9% at a current density of 1.0 A g^(-1) after 8000 cycles. This work may throw a light on simply the fabrication of other high-performance transition-metal nitridebased supercapacitor or other energy storage devices.展开更多
In this study,we used the modified CRISPR/Cas9 system to produce targeted point mutations in cauliflower.Acetolactate synthase(ALS)and Centromere-specific histone H3 variant(CENH3)genes were selected as the base-editi...In this study,we used the modified CRISPR/Cas9 system to produce targeted point mutations in cauliflower.Acetolactate synthase(ALS)and Centromere-specific histone H3 variant(CENH3)genes were selected as the base-editing targets and hypocotyls of cauliflower were used as explants.For ALS gene,a C-to-T conversion in the Pro182 codon(CCT)can alter the encoded amino acid,likely resulting in herbicide resistance,and a C-to-T mutation in the Leu133 codon(CTT)in the CENH3 gene may produce a haploid inducer.Results indicated that the transformation efficiency was 1.8%–4.5%and the mutation efficiencies for the ALS and CENH3 genes were approximately 22%and 87%,respectively.The ALS mutant cauliflower showed strong herbicide resistance,with possible immediate implications for broadleaf weed control in cauliflower fields.展开更多
The triblock copolymer(PAA-b-PAN-b-PAA) iSs prepared by reversible addition-fragmentation chaintransfer polymerization,and then blended with polymer(PAN) and metal hydroxide(Ni(OH)2) as a precursor for heat-treatment....The triblock copolymer(PAA-b-PAN-b-PAA) iSs prepared by reversible addition-fragmentation chaintransfer polymerization,and then blended with polymer(PAN) and metal hydroxide(Ni(OH)2) as a precursor for heat-treatment.A composite material of hierarchical porous nanofibers and nickel oxide nanopa rticles(HPCF@NiO) is prepared by electrospinning combined with high-tempe rature carbonization.The effects of the ratio of PAA and PAA-b-PAN-b-PAA on the internal structure of nanofibers and their electrochemical properties as positive electrode materials are investigated.The experimental results show that when the ratio of PAA to PAA-b-PAN-b-PAA is 1.3 to 0.4,it has good pore structure and excellent electrochemical performance.At the current density of 1 A/g,the specific capacitance is 188.7 F/g and the potential window is -1 V to 0.37 V.The asymmetric supercapacitor assembled with activated carbon as the negative electrode materials has a specific capacitance of 21.2 F/g in 2 mol/L KOH and a capacitance retention of 85.7% after 12,500 cycles at different current density.展开更多
基金supported by the National Natural Science Foundation of China (51203071,51363014,51463012,and 51763014)China Postdoctoral Science Foundation (2014M552509 and 2015T81064)+2 种基金Natural Science Funds of the Gansu Province (1506RJZA098)the Program for Hongliu Distinguished Young Scholars in Lanzhou University of Technology (J201402)Joint fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals (18LHPY002)
文摘Transition-metal nitrides exhibit wide potential windows and good electrochemical performance, but usually experience imbalanced practical applications in the energy storage field due to aggregation, poor circulation stability, and complicated syntheses. In this study, a novel and simple multiphase polymeric strategy was developed to fabricate hybrid vanadium nitride/carbon(VN/C) membranes for supercapacitor negative electrodes, in which VN nanoparticles were uniformly distributed in the hierarchical porous carbon 3D networks. The supercapacitor negative electrode based on VN/C membranes exhibited a high specific capacitance of 392.0 F g^(-1) at 0.5 A g^(-1) and an excellent rate capability with capacitance retention of 50.5% at 30 A g^(-1). For the asymmetric device fabricated using Ni(OH)_2//VN/C membranes, a high energy density of 43.0 Wh kg^(-1) at a power density of800 W kg^(-1) was observed. Moreover, the device also showed good cycling stability of 82.9% at a current density of 1.0 A g^(-1) after 8000 cycles. This work may throw a light on simply the fabrication of other high-performance transition-metal nitridebased supercapacitor or other energy storage devices.
基金partly funded by the project of technology innovation ability from Beijing Academy of Agriculture and Forestry Sciences (Grant Nos. KJCX20200401, KJCX20200205 and KJCX20200113)the Natural Science Foundation of China (Grant No. 31972401)
文摘In this study,we used the modified CRISPR/Cas9 system to produce targeted point mutations in cauliflower.Acetolactate synthase(ALS)and Centromere-specific histone H3 variant(CENH3)genes were selected as the base-editing targets and hypocotyls of cauliflower were used as explants.For ALS gene,a C-to-T conversion in the Pro182 codon(CCT)can alter the encoded amino acid,likely resulting in herbicide resistance,and a C-to-T mutation in the Leu133 codon(CTT)in the CENH3 gene may produce a haploid inducer.Results indicated that the transformation efficiency was 1.8%–4.5%and the mutation efficiencies for the ALS and CENH3 genes were approximately 22%and 87%,respectively.The ALS mutant cauliflower showed strong herbicide resistance,with possible immediate implications for broadleaf weed control in cauliflower fields.
基金partly supported by the National Natural Science Foundation of China(No.51763014)the Program for Hongliu Distinguished Young Scholars in Lanzhou University of Technology(No.J201801)Joint fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals(No.18LHPY002)。
文摘The triblock copolymer(PAA-b-PAN-b-PAA) iSs prepared by reversible addition-fragmentation chaintransfer polymerization,and then blended with polymer(PAN) and metal hydroxide(Ni(OH)2) as a precursor for heat-treatment.A composite material of hierarchical porous nanofibers and nickel oxide nanopa rticles(HPCF@NiO) is prepared by electrospinning combined with high-tempe rature carbonization.The effects of the ratio of PAA and PAA-b-PAN-b-PAA on the internal structure of nanofibers and their electrochemical properties as positive electrode materials are investigated.The experimental results show that when the ratio of PAA to PAA-b-PAN-b-PAA is 1.3 to 0.4,it has good pore structure and excellent electrochemical performance.At the current density of 1 A/g,the specific capacitance is 188.7 F/g and the potential window is -1 V to 0.37 V.The asymmetric supercapacitor assembled with activated carbon as the negative electrode materials has a specific capacitance of 21.2 F/g in 2 mol/L KOH and a capacitance retention of 85.7% after 12,500 cycles at different current density.
