Pot experiments were carried out to study the effect of nitrogen application on winter wheat under different status of soil moisture, so that the key and sensitive stage of winter wheat responses to water and nitrogen...Pot experiments were carried out to study the effect of nitrogen application on winter wheat under different status of soil moisture, so that the key and sensitive stage of winter wheat responses to water and nitrogen coordination were determined. The results showed that the application of N fertilizer was more effective in early stage than in later stage, and at the lower N rates than at the higher N rates under non-irrigated conditions. N treatments had great effect on spikelet bearing number and grain number per spike, but had no effect on 1 000-grain weight; Grain yield and yield component responses to N treatment were greater under irrigated conditions than under non-irrigated conditions. The joining stage was the key and sensitive stage of winter wheat responses to water and nitrogen coordination, and the grain yield, grain number per spike and 1000-grain weight increased, when water and N Fertilizer were applied at this stage. The mechanism is that water and fertilizer supply at joining stage can speed up the growth of above-ground crops, enhance the abilities to absorb and utilize nitrogen fertilizer, and meanwhile, delay the aging of the root and keep the root vigor for a longer period.展开更多
Now,Pt-based materials are still the best catalysts for hydrogen evolution reaction(HER).Nevertheless,the scarcity of Pt makes it impossible for the large-scale applications in industry.Although cobalt is taken as an ...Now,Pt-based materials are still the best catalysts for hydrogen evolution reaction(HER).Nevertheless,the scarcity of Pt makes it impossible for the large-scale applications in industry.Although cobalt is taken as an excellent HER catalyst due to its suitable H*binding,its alkali HER catalytic property need to be improved because of the sluggish water dissociation kinetics.In this work,nitrogen with small atomic radius and metallophilicity is employed to adjust local charges of atomically dispersed Mo^(δ+)sites on Co nanosheets to trigger water dissociation.Theoretical calculations suggest that the energy barrier of water dissociation can be effectively reduced by introducing nitrogen coordinated Mo^(δ+)sites.To realize this speculation,atomically dispersed Mo^(δ+)sites with nitrogen coordination of Mo(N)/Co were prepared via reconstruction of CoMoO_(4).High angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)and X-ray absorption spectroscopy(XAS)demonstrate the coordination of N atoms with atomically dispersed Mo atoms,leading to the local charges of atomically dispersed Mo^(δ+)sites in Mo(N)/Co.The measurement from ambient pressure X-ray photoelectron spectroscopy(AP-XPS)reveals that the Mo^(δ+)sites promote the adsorption and activation of water molecule.Therefore,the Mo(N)/Co exhibits an excellent activity,which need only an overpotential of 39 mV to reach the current density of 10 mA cm^(-2).The proposed strategy provides an advance pathway to design and boost alkaline HER activity at the atomic-level.展开更多
The environmental impact of elastomer waste,typically managed through incineration or landfilling,calls for more sustainable alternatives.Traditional thermoset elastomers,while strong and durable,are difficult to recy...The environmental impact of elastomer waste,typically managed through incineration or landfilling,calls for more sustainable alternatives.Traditional thermoset elastomers,while strong and durable,are difficult to recycle due to their permanent chemical crosslinks.Recent progress in supramolecular elastomers has improved recyclability but often at the expense of performance.Herein,we introduced a boron–nitrogen(B–N)and boron–oxygen(B–O)coordination-based supramolecular elastomer(BNOSE)that achieved both high mechanical strength and efficient chemical recyclability.The dynamic B–N and B–O bonds in BNOSE provided robust internal bonding,allowing thematerial to break down in amild ethanol solvent,while achieving high recovery rates.With a tensile strength over 43 MPa and toughness above 121 MJ/m3,BNOSE surpassedmany commercial elastomers and existing chemical recyclable thermoplastic elastomers.This material provided a sustainable solution without sacrificing performance,demonstrating potential for diverse applications such as soft robotics and flexible electronics.Additionally,its scalable design could be extended to other polymers,addressing the rising demand for high-performance,recyclable materials across various industries.展开更多
基金supported by the Key Program(30230230)Major Program(49890330)+1 种基金Special Program for Agriculture(30070429)of National Natural Science Foundation of ChinaNational Special Foundation for Key Basic Research,China(G1999011707).
文摘Pot experiments were carried out to study the effect of nitrogen application on winter wheat under different status of soil moisture, so that the key and sensitive stage of winter wheat responses to water and nitrogen coordination were determined. The results showed that the application of N fertilizer was more effective in early stage than in later stage, and at the lower N rates than at the higher N rates under non-irrigated conditions. N treatments had great effect on spikelet bearing number and grain number per spike, but had no effect on 1 000-grain weight; Grain yield and yield component responses to N treatment were greater under irrigated conditions than under non-irrigated conditions. The joining stage was the key and sensitive stage of winter wheat responses to water and nitrogen coordination, and the grain yield, grain number per spike and 1000-grain weight increased, when water and N Fertilizer were applied at this stage. The mechanism is that water and fertilizer supply at joining stage can speed up the growth of above-ground crops, enhance the abilities to absorb and utilize nitrogen fertilizer, and meanwhile, delay the aging of the root and keep the root vigor for a longer period.
基金the International Science and Technology Cooperation Program(2017YFE0127800 and 2018YFE0203400)the Natural Science Foundation of China(21872174,21762036 and U1932148)+7 种基金the Hunan Provincial Science and Technology Program(2017XK2026)the Shenzhen Science and Technology Innovation Project(JCYJ20180307151313532)Innovation and Entrepreneurship Training Program for College Students(S202110670023)the Natural Science Foundation of Science and Technology Department of Guizhou Province([2019]1297)the Special Project of Science and Technology Department of Guizhou Province([2020]QNSYXM03)the Natural Science Foundation of Education Department of Guizhou Province([2019]213,[2015]66)Teaching Quality Improvement Project of Qiannan Normal University for Nationalities([2017]50)the Beam Lines of BL01C1,BL24A1 in the NSRRC(MOST 109-2113-M-213-002)and beamline BL10B in National Synchrotron Radiation Laboratory。
文摘Now,Pt-based materials are still the best catalysts for hydrogen evolution reaction(HER).Nevertheless,the scarcity of Pt makes it impossible for the large-scale applications in industry.Although cobalt is taken as an excellent HER catalyst due to its suitable H*binding,its alkali HER catalytic property need to be improved because of the sluggish water dissociation kinetics.In this work,nitrogen with small atomic radius and metallophilicity is employed to adjust local charges of atomically dispersed Mo^(δ+)sites on Co nanosheets to trigger water dissociation.Theoretical calculations suggest that the energy barrier of water dissociation can be effectively reduced by introducing nitrogen coordinated Mo^(δ+)sites.To realize this speculation,atomically dispersed Mo^(δ+)sites with nitrogen coordination of Mo(N)/Co were prepared via reconstruction of CoMoO_(4).High angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)and X-ray absorption spectroscopy(XAS)demonstrate the coordination of N atoms with atomically dispersed Mo atoms,leading to the local charges of atomically dispersed Mo^(δ+)sites in Mo(N)/Co.The measurement from ambient pressure X-ray photoelectron spectroscopy(AP-XPS)reveals that the Mo^(δ+)sites promote the adsorption and activation of water molecule.Therefore,the Mo(N)/Co exhibits an excellent activity,which need only an overpotential of 39 mV to reach the current density of 10 mA cm^(-2).The proposed strategy provides an advance pathway to design and boost alkaline HER activity at the atomic-level.
基金supported by the Singapore National Research Fellowship(grant no.NRF-NRFF11-2019-0004)the Singapore Ministry of Education(MOE)Tier 2 Grant(grant no.MOE-T2EP30220-0006).
文摘The environmental impact of elastomer waste,typically managed through incineration or landfilling,calls for more sustainable alternatives.Traditional thermoset elastomers,while strong and durable,are difficult to recycle due to their permanent chemical crosslinks.Recent progress in supramolecular elastomers has improved recyclability but often at the expense of performance.Herein,we introduced a boron–nitrogen(B–N)and boron–oxygen(B–O)coordination-based supramolecular elastomer(BNOSE)that achieved both high mechanical strength and efficient chemical recyclability.The dynamic B–N and B–O bonds in BNOSE provided robust internal bonding,allowing thematerial to break down in amild ethanol solvent,while achieving high recovery rates.With a tensile strength over 43 MPa and toughness above 121 MJ/m3,BNOSE surpassedmany commercial elastomers and existing chemical recyclable thermoplastic elastomers.This material provided a sustainable solution without sacrificing performance,demonstrating potential for diverse applications such as soft robotics and flexible electronics.Additionally,its scalable design could be extended to other polymers,addressing the rising demand for high-performance,recyclable materials across various industries.
