Before the practical application of rechargeable Zn-air batteries(ZABs),a critical issue regarding the inherent slow reaction kinetics of the oxygen reduction(ORR)and oxygen evolution(OER)must be addressed.Here,we fab...Before the practical application of rechargeable Zn-air batteries(ZABs),a critical issue regarding the inherent slow reaction kinetics of the oxygen reduction(ORR)and oxygen evolution(OER)must be addressed.Here,we fabricate a cost-effective bifunctional oxygen electrocatalyst with a self-antistacking structure,where three-dimensional(3D)Fe-Co bimetallic oxide particles(FeCoO_(x))are directly grown on 2D N-doped graphene(NG).The in situ grown FeCoO_(x)particles can alleviate the NG interlaminar restacking,ensuring abundant channels for diffusion of O_(2)/OH−species,while the NG allows rapid electron flow.Benefiting from this self-antistacking 3D-on-2D structure and synergetic electrocatalysis,FeCoO_(x)@NG demonstrated excellent activity for both ORR and OER(ΔE=0.78 V),which is superior to that of the binary mixtures of Pt/C and RuO_(2)(ΔE=0.83 V).A homemade ZAB with 20%-FeCoO_(x)@NG delivers a specific capacity of 758.9 mAh g^(−1),a peak power density of 215 mW cm^(−2),and long-term cyclability for over 400 h.These research results suggest that designing a bimetallic oxide/N-doped carbon 3D-on-2D nanoarchitecture using an in situ growth strategy is an attractive and feasible solution to overcome electrocatalytic problems in ZABs.展开更多
Grain storage security is big issue related to national economy and the people＇s livelihood, as well as one of the most important strategic requirements in China. Under the background of grain supply-side structural ...Grain storage security is big issue related to national economy and the people＇s livelihood, as well as one of the most important strategic requirements in China. Under the background of grain supply-side structural reform, this paper analyzed the grain storage security countermeasures under the new normal conditions with ＂grain storage technology＂, one of the national grain security strategies of China during the 13th Five-year Plan, as the guiding ideology, from the perspectives of scientific technologies, policy supports, government supports and talent construction, so as to provide supports for the storage enterprises with vulnerable technological links. In addition, the food security issues discussed in this paper could be a helping hand in improving people＇s living quality, enhancing grain storage ecological quality, promoting grain green storage quality security, and be of important and profound strategic significance to enhance the macro-control capability of the government, maintain social stability and people＇s health.展开更多
In this work, we proposed a novel three-dimensional (3D) plasmonic nanostructure based on porous graphene/nickel foam (GNF) and gas-phase deposited Ag nanoparticles (NPs). Ag NPs with high density were directly deposi...In this work, we proposed a novel three-dimensional (3D) plasmonic nanostructure based on porous graphene/nickel foam (GNF) and gas-phase deposited Ag nanoparticles (NPs). Ag NPs with high density were directly deposited on the surface of 3D GNF by performing a novel cluster beam deposition approach. In comparison with traditional Ag substrate (SiO2/Ag), such hot-spots enriched 3D nanostructure showed extremely high electromag-netic field enhancement under incident light irradiation which could be used as a sensitive chemical sensor based on surface enhanced Raman scattering (SERS). The experimental results demonstrated that the proposed nanostructure showed superior SERS performance in terms of Raman signal reproducibility and sensitivity for the probe molecules. 3D full-wave simulation showed that the enhanced SERS performance in this 3D hierarchical plasmonic nanostructure was mainly obtained from the hot-spots between Ag NPs and the near-field coupling between Ag NPs and GNF sca olds. This work can provide a novel assembled SERS substrate as a SERS-based chemical sensor in practical applications.展开更多
A polystyrene（PS）/nanosilica organic-inorganic hybrid material was prepared from styrene monomer and commercial aqueous silica sol containing large amounts of Si-OH by means of emulsion polymerization. The nanosilic...A polystyrene（PS）/nanosilica organic-inorganic hybrid material was prepared from styrene monomer and commercial aqueous silica sol containing large amounts of Si-OH by means of emulsion polymerization. The nanosilica sol was modified by the addition of the reactive coupling agent methacrylexy propyltrimethoxysilane （ MPS）, and the resulting latex particles were protected by surfactants such as sodium dodecyl sulphonate（ SDS）, hydroxypropyl methyl cellulose （ HMPC）, and poly （vinylpyrrolidone） （PVP）. The effects of the type of surfactant, the amount of surfactant, and the coupling agent on the shape and stability of the resulting latex particles were investigated. The TEM observation indicates that among SDS, HMPC, and PVP, SDS is the best surfactant. When the content of SDS is 0. 5% and the amount of MPS is 7% in the system, the latex with obvious core-shell structure could be obtained. The average diameters of the monodispersed particles range from 182 to 278 nm, and the average number of silica beads for each composite are 1325 and 4409, respectively. The FrIR analysis shows that PS was chemically linked to silica through MPS. The thermal gravimetric analysis shows that when there is a higher silica content, the hybrid composites have a better heat resistance.展开更多
With the rapid development of digital signal processing chip in recent years, DSP began to be used in more switching power supply. The advantages of digital control of their own, making the digital control PFC become ...With the rapid development of digital signal processing chip in recent years, DSP began to be used in more switching power supply. The advantages of digital control of their own, making the digital control PFC become a hotspot research. However, compared with the simulation system, the digital control technology still has many problems. In this paper, the problem of digital PI compensator as a voltage compensator is discussed, and the Single-pole voltage loop compensator is used in digital control PFC circuit. Because current loop bandwidth is narrow, a method to expand current loop bandwidth is put forward. Output power 300 W of prototype is made, and experimental results verify the correctness of the theory.展开更多
Albino tea,a type of tea closely associated with the chlorophyll-deficient phenotype is of great interest due to its multiple benefits to human health.To explore the potential mechanisms involved in albino tea,we perf...Albino tea,a type of tea closely associated with the chlorophyll-deficient phenotype is of great interest due to its multiple benefits to human health.To explore the potential mechanisms involved in albino tea,we performed metabolomics,DNA methylation and RNA-Seq analysis of green and albino leaves in a special tea mutant'Haishun 2'.The albino leaves accumulated significantly less catechins compared with the green leaves,which is closely associated with their difference in chlorophyll formation.A total of 385 candidate genes were identified by the integrative analysis.Two NAC transcription factors were less methylated and highly up regulated in the albino leaves of'Haishun 2',which was the first identification of the key roles of NAC transcription factors in albino tea and worth further study.Many genes involved in catechin biosynthesis were down regulated in albino leaves,such as 4-coumarate-CoA ligase,flavonol synthase and leucoanthocyanidin reductase genes,suggesting chlorophyll formation is important for catechin biosynthesis.Furthermore,CsMYB5 and CsGSTF11 were found to be differentially methylated and expressed in albino and green leaves,indicating their potential roles in catechin accumulation.This was the first report of the integrative analysis of transcriptome and DNA methylation data in tea plants and the results suggest that the integrative analysis is useful for exploring key genes associated with epigenetic changes in tea plants.展开更多
One new bisbenzylisoquinoline alkaloid, neferine N-oxide （1）, along with three known compounds, neferine （2）, liensinine （3）, and isoliensinine （4）, were isolated from Plumulanelumbinis - the embryo of the see...One new bisbenzylisoquinoline alkaloid, neferine N-oxide （1）, along with three known compounds, neferine （2）, liensinine （3）, and isoliensinine （4）, were isolated from Plumulanelumbinis - the embryo of the seed of Nelumbonucifera. Their structures were elucidated by extensive spectroscopic analysis （MS, UV, IR, NMR）, and the absolute configurations were determined by experimental circulardichroism （CD） spectra. Compound 1 is a new naturally occurring bisbenzylisoquinoline alkaloid with an N-oxide functionality, and the CD spectrum of （1R, 1＇R） neferine is first reported. The antioxidant activities of compounds 1-4 were evaluated using the ORAC assay, which illustrated that all these compounds showed the different levels of oxygen radical absorbance capacity.展开更多
While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emi...While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emitting diodes(LEDs),which are a backbone for energy-efficient light sources.In the case of LEDs,TIR prevents photons from escaping the constituent high-index materials.Advances in material science have led to good efficiencies in generating photons from electron–hole pairs,making light extraction the bottleneck of the overall efficiency of LEDs.In recent years,the extraction efficiency has been improved,using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum.However,the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and timeconsuming fabrication,which causes a gap between lab demonstration and industrial-level applications.Inspired by lightning bugs,we propose and realise a disordered metasurface for light extraction throughout the visible spectrum,achieved with single-step fabrication.By applying such a cost-effective light extraction layer,we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs,demonstrating a substantial potential for global energy-saving and sustainability.展开更多
An ideal organic thin film photodetectors(OTFPs) should adopt a hierarchical, multilayer p-type/blend-type/n-type(PIN) structure,with each layer having a specific purpose which could greatly improve the exciton dissoc...An ideal organic thin film photodetectors(OTFPs) should adopt a hierarchical, multilayer p-type/blend-type/n-type(PIN) structure,with each layer having a specific purpose which could greatly improve the exciton dissociation while guarantee efficient charge transport. However, for the traditional layer-by-layer solution fabrication procedure, the solvent used can induce organic material mixing and molecular disordering between each layer. Hence, such architecture for OTFPs can now only be formed via thermal evaporation. In this paper, a contact-film-transfer method is demonstrated to all-solution processing organic PIN OTFPs on flexible substrates. The fabricated PIN OTFPs exhibit high photoresponse and high stability under continuous mechanical bending. Hence,the method we described here should represent an important step in the development of OTFPs in the future.展开更多
基金Natural Science Foundation of Jiangsu forthe Outstanding Youth Fund,Grant/Award Number:BK20211590National Natural Science Foundation ofChina,Grant/Award Number:51802152。
文摘Before the practical application of rechargeable Zn-air batteries(ZABs),a critical issue regarding the inherent slow reaction kinetics of the oxygen reduction(ORR)and oxygen evolution(OER)must be addressed.Here,we fabricate a cost-effective bifunctional oxygen electrocatalyst with a self-antistacking structure,where three-dimensional(3D)Fe-Co bimetallic oxide particles(FeCoO_(x))are directly grown on 2D N-doped graphene(NG).The in situ grown FeCoO_(x)particles can alleviate the NG interlaminar restacking,ensuring abundant channels for diffusion of O_(2)/OH−species,while the NG allows rapid electron flow.Benefiting from this self-antistacking 3D-on-2D structure and synergetic electrocatalysis,FeCoO_(x)@NG demonstrated excellent activity for both ORR and OER(ΔE=0.78 V),which is superior to that of the binary mixtures of Pt/C and RuO_(2)(ΔE=0.83 V).A homemade ZAB with 20%-FeCoO_(x)@NG delivers a specific capacity of 758.9 mAh g^(−1),a peak power density of 215 mW cm^(−2),and long-term cyclability for over 400 h.These research results suggest that designing a bimetallic oxide/N-doped carbon 3D-on-2D nanoarchitecture using an in situ growth strategy is an attractive and feasible solution to overcome electrocatalytic problems in ZABs.
基金Supported by the Fund Project for the Scientific Undertakings in Public Interest of Liaoning Province(20170046)the Initiation Project of Economic and Social Development of Liaoning Province(2018lslktyb)the Initiation Project of Economic and Social Development of Shenyang City in 2017(SYSK2017-13-11)~~
文摘Grain storage security is big issue related to national economy and the people＇s livelihood, as well as one of the most important strategic requirements in China. Under the background of grain supply-side structural reform, this paper analyzed the grain storage security countermeasures under the new normal conditions with ＂grain storage technology＂, one of the national grain security strategies of China during the 13th Five-year Plan, as the guiding ideology, from the perspectives of scientific technologies, policy supports, government supports and talent construction, so as to provide supports for the storage enterprises with vulnerable technological links. In addition, the food security issues discussed in this paper could be a helping hand in improving people＇s living quality, enhancing grain storage ecological quality, promoting grain green storage quality security, and be of important and profound strategic significance to enhance the macro-control capability of the government, maintain social stability and people＇s health.
基金supported by the National Natural Science Foundation of China (No.11604161)the Natural Science Foundation of Jiangsu Province (No.BK20160914)+2 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.16KJB140009)the Foundation from Nanjing University of Posts and Telecommunication (No.NY216012)the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sk lodowska-Curie Grant (No.752102)
文摘In this work, we proposed a novel three-dimensional (3D) plasmonic nanostructure based on porous graphene/nickel foam (GNF) and gas-phase deposited Ag nanoparticles (NPs). Ag NPs with high density were directly deposited on the surface of 3D GNF by performing a novel cluster beam deposition approach. In comparison with traditional Ag substrate (SiO2/Ag), such hot-spots enriched 3D nanostructure showed extremely high electromag-netic field enhancement under incident light irradiation which could be used as a sensitive chemical sensor based on surface enhanced Raman scattering (SERS). The experimental results demonstrated that the proposed nanostructure showed superior SERS performance in terms of Raman signal reproducibility and sensitivity for the probe molecules. 3D full-wave simulation showed that the enhanced SERS performance in this 3D hierarchical plasmonic nanostructure was mainly obtained from the hot-spots between Ag NPs and the near-field coupling between Ag NPs and GNF sca olds. This work can provide a novel assembled SERS substrate as a SERS-based chemical sensor in practical applications.
基金Supported by the National Natural Science Foundation of China(No. 50373037)the Special Funds for Major State BasicResearch Projects ( No. 2005CB623802) Specialized Research Fund for the Doctoral Program of Higher Education ( No.20040335077).
文摘A polystyrene（PS）/nanosilica organic-inorganic hybrid material was prepared from styrene monomer and commercial aqueous silica sol containing large amounts of Si-OH by means of emulsion polymerization. The nanosilica sol was modified by the addition of the reactive coupling agent methacrylexy propyltrimethoxysilane （ MPS）, and the resulting latex particles were protected by surfactants such as sodium dodecyl sulphonate（ SDS）, hydroxypropyl methyl cellulose （ HMPC）, and poly （vinylpyrrolidone） （PVP）. The effects of the type of surfactant, the amount of surfactant, and the coupling agent on the shape and stability of the resulting latex particles were investigated. The TEM observation indicates that among SDS, HMPC, and PVP, SDS is the best surfactant. When the content of SDS is 0. 5% and the amount of MPS is 7% in the system, the latex with obvious core-shell structure could be obtained. The average diameters of the monodispersed particles range from 182 to 278 nm, and the average number of silica beads for each composite are 1325 and 4409, respectively. The FrIR analysis shows that PS was chemically linked to silica through MPS. The thermal gravimetric analysis shows that when there is a higher silica content, the hybrid composites have a better heat resistance.
文摘With the rapid development of digital signal processing chip in recent years, DSP began to be used in more switching power supply. The advantages of digital control of their own, making the digital control PFC become a hotspot research. However, compared with the simulation system, the digital control technology still has many problems. In this paper, the problem of digital PI compensator as a voltage compensator is discussed, and the Single-pole voltage loop compensator is used in digital control PFC circuit. Because current loop bandwidth is narrow, a method to expand current loop bandwidth is put forward. Output power 300 W of prototype is made, and experimental results verify the correctness of the theory.
基金the Central Publicinterest Scientific Institution Basal Research Fund(1610212020002)the Major Project of Agricultural Science and Technology in Breeding of Tea Plant Variety in Zhejiang Province(2021C02067)Earmarked Fund for China Agriculture Research System(CARS-19).
文摘Albino tea,a type of tea closely associated with the chlorophyll-deficient phenotype is of great interest due to its multiple benefits to human health.To explore the potential mechanisms involved in albino tea,we performed metabolomics,DNA methylation and RNA-Seq analysis of green and albino leaves in a special tea mutant'Haishun 2'.The albino leaves accumulated significantly less catechins compared with the green leaves,which is closely associated with their difference in chlorophyll formation.A total of 385 candidate genes were identified by the integrative analysis.Two NAC transcription factors were less methylated and highly up regulated in the albino leaves of'Haishun 2',which was the first identification of the key roles of NAC transcription factors in albino tea and worth further study.Many genes involved in catechin biosynthesis were down regulated in albino leaves,such as 4-coumarate-CoA ligase,flavonol synthase and leucoanthocyanidin reductase genes,suggesting chlorophyll formation is important for catechin biosynthesis.Furthermore,CsMYB5 and CsGSTF11 were found to be differentially methylated and expressed in albino and green leaves,indicating their potential roles in catechin accumulation.This was the first report of the integrative analysis of transcriptome and DNA methylation data in tea plants and the results suggest that the integrative analysis is useful for exploring key genes associated with epigenetic changes in tea plants.
基金financially supported by 12th Five-Year Plan Major New Drug Discovery Science and Technology Projects for support of this research (No.2014ZX09304307-002)
文摘One new bisbenzylisoquinoline alkaloid, neferine N-oxide （1）, along with three known compounds, neferine （2）, liensinine （3）, and isoliensinine （4）, were isolated from Plumulanelumbinis - the embryo of the seed of Nelumbonucifera. Their structures were elucidated by extensive spectroscopic analysis （MS, UV, IR, NMR）, and the absolute configurations were determined by experimental circulardichroism （CD） spectra. Compound 1 is a new naturally occurring bisbenzylisoquinoline alkaloid with an N-oxide functionality, and the CD spectrum of （1R, 1＇R） neferine is first reported. The antioxidant activities of compounds 1-4 were evaluated using the ORAC assay, which illustrated that all these compounds showed the different levels of oxygen radical absorbance capacity.
基金P.M.and M.H.acknowledge the financial support from by National Natural Science Foundation of China(Grant No.11627806,U1909214,11604161)the National Key R&D Program of China(Grant No.2016YFA0201002)+5 种基金P.M.acknowledges the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant(Grant No.752102)C.L.acknowledges the financial support from Humboldt Research Fellowship from Alexander von Humboldt Foundation.P.M.,C.L.and S.Z acknowledge 2020 European Research Council Project Nos.734578(D-SPA)and 648783(TOPOLOGICAL)Leverhulme Trust(grant no.RPG-2012-674)the Royal Society,the Wolfson Foundation.S.A.M.acknowledges funding support from the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy,EXC 2089/1-390776260the Solar Energies go Hybrid(SolTech)programme,the EPSRC Reactive Plasmonics Programme(EP/M013812/1)the Lee-Lucas Chair in Physics.X.L.,M.L.and E.S.acknowledge financial support from the Natural Sciences and Engineering Research Council(NSERC)of Canada.
文摘While total internal reflection(TIR)lays the foundation for many important applications,foremost fibre optics that revolutionised information technologies,it is undesirable in some other applications such as light-emitting diodes(LEDs),which are a backbone for energy-efficient light sources.In the case of LEDs,TIR prevents photons from escaping the constituent high-index materials.Advances in material science have led to good efficiencies in generating photons from electron–hole pairs,making light extraction the bottleneck of the overall efficiency of LEDs.In recent years,the extraction efficiency has been improved,using nanostructures at the semiconductor/air interface that outcouple trapped photons to the outside continuum.However,the design of geometrical features for light extraction with sizes comparable to or smaller than the optical wavelength always requires sophisticated and timeconsuming fabrication,which causes a gap between lab demonstration and industrial-level applications.Inspired by lightning bugs,we propose and realise a disordered metasurface for light extraction throughout the visible spectrum,achieved with single-step fabrication.By applying such a cost-effective light extraction layer,we improve the external quantum efficiency by a factor of 1.65 for commercialised GaN LEDs,demonstrating a substantial potential for global energy-saving and sustainability.
基金supported by the National Basic Research Program of China (2014CB643600, 2014CB643503)
文摘An ideal organic thin film photodetectors(OTFPs) should adopt a hierarchical, multilayer p-type/blend-type/n-type(PIN) structure,with each layer having a specific purpose which could greatly improve the exciton dissociation while guarantee efficient charge transport. However, for the traditional layer-by-layer solution fabrication procedure, the solvent used can induce organic material mixing and molecular disordering between each layer. Hence, such architecture for OTFPs can now only be formed via thermal evaporation. In this paper, a contact-film-transfer method is demonstrated to all-solution processing organic PIN OTFPs on flexible substrates. The fabricated PIN OTFPs exhibit high photoresponse and high stability under continuous mechanical bending. Hence,the method we described here should represent an important step in the development of OTFPs in the future.
