The C.oleifera oil processing industry generates large amounts of solid wastes,including C.oleifera shell(COS)and C.oleifera cake(COC).Distinct from generally acknowledged lignocellulosic biomass(corn stover,bamboo,bi...The C.oleifera oil processing industry generates large amounts of solid wastes,including C.oleifera shell(COS)and C.oleifera cake(COC).Distinct from generally acknowledged lignocellulosic biomass(corn stover,bamboo,birch,etc.),Camellia wastes contain diverse bioactive substances in addition to the abundant lignocellulosic components,and thus,the biorefinery utilization of C.oleifera processing byproducts involves complicated processing technologies.This reviewfirst summarizes various technologies for extracting and converting the main components in C.oleifera oil processing byproducts into value-added chemicals and biobased materials,as well as their potential applications.Microwave,ultrasound,and Soxhlet extractions are compared for the extraction of functional bioactive components(tannin,flavonoid,saponin,etc.),while solvothermal conversion and pyrolysis are discussed for the conversion of lignocellulosic components into value-added chemicals.The application areas of these chemicals according to their properties are introduced in detail,including utilizing antioxidant and anti-in-flammatory properties of the bioactive substances for the specific application,as well as drop-in chemicals for the substitution of unrenewable fossil fuel-derived products.In addition to chemical production,biochar fabricated from COS and its applications in thefields of adsorption,supercapacitor,soil remediation and wood composites are comprehensively reviewed and discussed.Finally,based on the compositions and structural characteristics of C.oleifera byproducts,the development of full-component valorization strategies and the expansion of the appli-cationfields are proposed.展开更多
Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous ...Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.展开更多
As an alternative to conventional energy conversion and storage reactions,gas-involved electrochemical reactions,including the carbon dioxide reduction reaction(CO_(2)RR),nitrogen reduction reaction(NRR)and hydrogen e...As an alternative to conventional energy conversion and storage reactions,gas-involved electrochemical reactions,including the carbon dioxide reduction reaction(CO_(2)RR),nitrogen reduction reaction(NRR)and hydrogen evolution reaction(HER),have become an emerging research direction and have gained increasing attention due to their advantages of environmental friendliness and sustainability.Various studies have been designed to accelerate sluggish kinetics but with limited results.Most of them promote the reaction by modulating the intrinsic properties of the catalyst,ignoring the synergistic effect of the reaction as a whole.Due to the introduction of gas,traditional liquid-solid two-phase reactions are no longer applicable to future research.Since gas-involved electrochemical reactions mostly occur at the junctions of gaseous reactants,liquid electrolytes and solid catalysts,the focus of future research on reaction kinetics should gradually shift to three-phase reaction interfaces.In this review,we briefly introduce the formation and constraints of the three-phase interface and propose three criteria to judge its merit,namely,the active site,mass diffusion and electron mass transfer.Subsequently,a series of modulation methods and relevant works are discussed in detail from the three improvement directions of‘exposing more active sites,promoting mass diffusion and accelerating electron transfer’.Definitively,we provide farsighted insights into the understanding and research of three-phase interfaces in the future and point out the possible development direction of future regulatory methods,hoping that this review can broaden the future applications of the three-phase interface,including but not limited to gas-involved electrochemical reactions.展开更多
Light confinement induced by spontaneous near-surface resonance is inherently determined by the location and geometry of metallic nanostructures(NSs),offering a facile and effective approach to break through the limit...Light confinement induced by spontaneous near-surface resonance is inherently determined by the location and geometry of metallic nanostructures(NSs),offering a facile and effective approach to break through the limitation of the light-mater interaction within the photoactive layers.Here,we demonstrate high-performance Al NS/ZnO quantum dots(Al/ZnO) heterostructure UV photodetectors with controllable morphologies of the self-assembled Al NSs.The Al/ZnO heterostructures exhibit a superior light utilization than the ZnO/Al heterostructures,and a strong morphological dependence of the Al NSs on the optical properties of the heterostructures.The inter-diffusion of Al atoms into ZnO matrixes is of a great benefit for the carrier transportation.Consequently,the optimal photocurrent of the Al/ZnO heterostructure photodetectors is significantly increased by 275 times to ~1.065 mA compared to that of the pristine ZnO device,and an outstanding photoresponsivity of 11.98 A W-1 is correspondingly achieved under 6.9 MW cm-2 UV light illumination at 10 V bias.In addition,a relatively fast response is similarly witnessed with the Al/ZnO devices,paving a path to fabricate the high-performance UV photodetectors for applications.展开更多
Lonicerae Flos(LF)derived from the dried flower buds or opening flowers of four Lonicera plants(Lonicera macranthoides,L.hypoglauca,L.confusa,and L.fulvotnetosa),is a popular traditional Chinese medicine.Because the f...Lonicerae Flos(LF)derived from the dried flower buds or opening flowers of four Lonicera plants(Lonicera macranthoides,L.hypoglauca,L.confusa,and L.fulvotnetosa),is a popular traditional Chinese medicine.Because the four origin plants are very similar in morphology,it is difficult to control the quality of LF in actual production.Over the past decade,many reports have pointed out the differences among them,including the botanical characteristics and active ingredients.However,there is still a lack of rapid methods that can be applied to the identification of the four origins.In this study,comparative analysis of the four chloroplast genomes was performed,and they showed low diversity(Pi=0.00267),three variation hotspots regions(rbcL-accD,rps12-ndhF and rps12-trnN-trnG)were identified as potentially molecular marker of highly informative.Meanwhile,the most obvious difference in SSR comparative analysis is reverse and complement repeats were only identified in L.confusa and L.hypoglauca,respectively.Lastly,the phylogenetic tree showed that L.confusa is more closely related to L.fulvotnetosa,while L.macranthoides is closer to L.hypoglauca.This study systematically revealed the differences among the four chloroplast genomes,and it provides valuable genetic information for identifying the origin of LF.展开更多
Currently,the only central bank digital currencies(CBDC)in the world is Venezuela^currency^Petro.Nowadays,the IMF,BIS,and major countries have conducted a lot of research on CBDC.It's an urgent issue for the centr...Currently,the only central bank digital currencies(CBDC)in the world is Venezuela^currency^Petro.Nowadays,the IMF,BIS,and major countries have conducted a lot of research on CBDC.It's an urgent issue for the central bank to issue CBDC,determine and formulate the circulation of CBDC and the issuance speed,and supervise it.Therefore,establishing ARMA and VARs by sorting out literature,the paper uses the characteristics of CBDC—cash,and similarities with third-party payment in terms of payment to determine the circulation of CDBC by third-party payment users and currency in circulation.The model calculates and predicts the speed of circulation of digital currency.The issuance of CBDC will accelerate the circulation of money.In this regard,we will explore the impact of money supply on monetary policy and make relevant recommendations.展开更多
The micro crack of aluminum sheet during cold rolling lubricated with emulsions is investigated. Experi-ments show that micro cracks occur after cold rolling process and this is attributed to various parameters, for i...The micro crack of aluminum sheet during cold rolling lubricated with emulsions is investigated. Experi-ments show that micro cracks occur after cold rolling process and this is attributed to various parameters, for instance, the thin oxide film formed at the sheet surface. The micro crack spacing thus becomes an important parameter which deserves more concerns. The aspect ratio of these micro cracks is then analyzed theoreti-cally, which takes into consideration of the oxide fracture process. The good agreement between the obser-vations and the theoretical predictions validates the analysis. The approach can shed some new lights on the mechanical process of aluminium sheet during cold rolling.展开更多
Nitrogen chemisorption is a prerequisite for efficient ammonia synthesis under ambient conditions,but promoting this process remains a significant challenge.Here,by loading yttrium clusters onto a single-atom support,...Nitrogen chemisorption is a prerequisite for efficient ammonia synthesis under ambient conditions,but promoting this process remains a significant challenge.Here,by loading yttrium clusters onto a single-atom support,an electronic promoting effect is triggered to successfully eliminate the nitrogen chemisorption barrier and achieve highly efficient ammonia synthesis.Density functional theory calculations reveal that yttrium clusters with abundant electron orbitals can provide considerable electrons and greatly promote electron backdonation to the N2 antibonding orbitals,making the chemisorption process exothermic.Moreover,according to the“hot atom”mechanism,the energy released during exothermic N2 chemisorption would benefit subsequent N2 cleavage and hydrogenation,thereby dramatically reducing the energy barrier of the overall process.As expected,the proof-of-concept catalyst achieves a prominent NH3 yield rate of 48.1μg·h^(−1)·mg^(−1)at−0.2 V versus the reversible hydrogen electrode,with a Faradaic efficiency of up to 69.7%.This strategy overcomes one of the most serious obstacles for electrochemical ammonia synthesis,and provides a promising method for the development of catalysts with high catalytic activity and selectivity.展开更多
Infrared(IR)solar cells are promising devices for improving the power conversion efficiency(PCE)of conventional solar cells by expanding the utilization region of the sunlight spectrum to near-infrared range.IR solar ...Infrared(IR)solar cells are promising devices for improving the power conversion efficiency(PCE)of conventional solar cells by expanding the utilization region of the sunlight spectrum to near-infrared range.IR solar cells based on colloidal quantum dots(QDs)have attracted extensive attention due to the widely tunable absorption spectrum controlled by dot size and the unique solution processibility.However,the trade-off in QD solar cells between light absorption and photo-generated carrier collection has limited the further improvement of PCE.Here,we present high-performance PbS QD IR solar cells resulting from the combination of boosted light absorption and optimized carrier extraction.By constructing an optical resonance cavity,the light absorption is significantly enhanced in the range of 1,150–1,300 nm at a relatively thin photoactive layer.Meanwhile,the thin photoactive layer facilitates efficient carrier extraction.Consequently,the PbS QD IR solar cells exhibit a highly efficient photoelectric conversion in the IR region,resulting in a high IR PCE of 1.3%which is comparable to the highest value of solution-processed IR solar cells based on PbSe QDs.These results demonstrate that constructing an optical resonance cavity is a reasonable strategy for effective conversion of photons in the devices aiming at light in a relatively narrow wavelength range,such as IR solar cells and narrow band photodetectors.展开更多
Single nucleotide polymorphism (SNP) is a common form of genetic variation and popularly exists in maize genome. An Illumina GoldenGate assay with 1 536 SNP markers was used to genotype maize inbred lines and identifi...Single nucleotide polymorphism (SNP) is a common form of genetic variation and popularly exists in maize genome. An Illumina GoldenGate assay with 1 536 SNP markers was used to genotype maize inbred lines and identified the functional genetic variations underlying drought tolerance by association analysis. Across 80 lines, 1 006 polymorphic SNPs (65.5% of the total) in the assay with good call quality were used to estimate the pattern of genetic diversity, population structure, and familial relatedness. The analysis showed the best number of fixed subgroups was six, which was consistent with their original sources and results using only simple sequence repeat markers. Pairwise linkage disequilibrium (LD) and association mapping with phenotypic traits investigated under water-stressed and well-watered regimes showed rapid LD decline within 100-500 kb along the physical distance of each chromosome, and that 29 SNPs were associated with at least two phenotypic traits in one or more environments, which were related to drought-tolerant or drought-responsive genes. These drought-tolerant SNPs could be converted into functional markers and then used for maize improvement by marker-assisted selection.展开更多
Insects utilize xenobiotic compounds to up-and downregulate cytochrome P450 monooxygenases(P450s)involved in detoxification of toxic xenobiotics including phytochemicals and pesticides.G-quadruplexes(G4)-forming DNA m...Insects utilize xenobiotic compounds to up-and downregulate cytochrome P450 monooxygenases(P450s)involved in detoxification of toxic xenobiotics including phytochemicals and pesticides.G-quadruplexes(G4)-forming DNA motifs are enriched in the promoter regions of transcription factors and function as cis-acting elements to regulate these genes.Whether and how P450s gain and keep G4 DNA motifs to regulate their expression still remain unexplored.Here,we show that CYP321A1,a xenobiotic-metabolizing P450 from Helicoverpa zea,a polyphagous insect of economic importance,has acquired and preserved a G4 DNA motif by selectively retaining a transposon known as HzIS1-3 that carries this G4 DNA motif in its promoter region.The HzIS1-3 G4 DNA motif acts as a silencer to suppress the constitutive and induced expression of CYP321A1 by plant allelochemicals flavone and xanthotoxin through folding into an intramolecular parallel or hybrid-1 conformation in the absence or presence of K^(+).The G4 ligand N-methylmesoporphyrin IX(NMM)strengthens the silencing effect of HzIS1-3 G4 DNA motif by switching its structure from hybrid-1 to hybrid-2.The enrichment of transposons in P450s and other environment-adaptation genes implies that selective retention of G4 DNA motif-carrying transposons may be the main evolutionary route for these genes to obtain G4 DNA motifs.展开更多
The passive sampling technique, diffusive gradients in thin films(DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per-and polyfluoroalkyl substances(PFAS). However, its...The passive sampling technique, diffusive gradients in thin films(DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per-and polyfluoroalkyl substances(PFAS). However, its effectiveness has been questioned because of the small effective sampling area(3.1 cm^(2)). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area(27 cm^(2)) and as a result lower method quantification limits(0.15 –0.21 ng/L for one-day deployment and 0.02 – 0.03 ng/L for one-week deployment) and much higher(by > 10 factors) sampling rate(100 m L/day) compared to the standard DGT(piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling(500m L). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.展开更多
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Grant No.32201509)Hunan Science and Technology Xiaohe Talent Support Project(2022 TJ-XH 013)+6 种基金Science and Technology Innovation Program of Hunan Province(2022RC1156,2021RC2100)State Key Laboratory of Woody Oil Resource Utilization Common Key Technology Innovation for the Green Transformation of Woody Oil(XLKY202205)State Key Laboratory of Woody Oil Resource Utilization Project(2019XK2002)Key Research and Development Program of the State Forestry and Grassland Administration(GLM[2021]95)Hunan Forestry Outstanding Youth Project(XLK202108-1)Changsha Science and Technology Project(kq2202325,kq2107022)Science and Technology Innovation Leading Talent of Hunan Province(2020RC4026).
文摘The C.oleifera oil processing industry generates large amounts of solid wastes,including C.oleifera shell(COS)and C.oleifera cake(COC).Distinct from generally acknowledged lignocellulosic biomass(corn stover,bamboo,birch,etc.),Camellia wastes contain diverse bioactive substances in addition to the abundant lignocellulosic components,and thus,the biorefinery utilization of C.oleifera processing byproducts involves complicated processing technologies.This reviewfirst summarizes various technologies for extracting and converting the main components in C.oleifera oil processing byproducts into value-added chemicals and biobased materials,as well as their potential applications.Microwave,ultrasound,and Soxhlet extractions are compared for the extraction of functional bioactive components(tannin,flavonoid,saponin,etc.),while solvothermal conversion and pyrolysis are discussed for the conversion of lignocellulosic components into value-added chemicals.The application areas of these chemicals according to their properties are introduced in detail,including utilizing antioxidant and anti-in-flammatory properties of the bioactive substances for the specific application,as well as drop-in chemicals for the substitution of unrenewable fossil fuel-derived products.In addition to chemical production,biochar fabricated from COS and its applications in thefields of adsorption,supercapacitor,soil remediation and wood composites are comprehensively reviewed and discussed.Finally,based on the compositions and structural characteristics of C.oleifera byproducts,the development of full-component valorization strategies and the expansion of the appli-cationfields are proposed.
基金supported by the National Natural Science Foundation of China(U21A20332,52103226,52202275,52203314,and 12204253)the Distinguished Young Scholars Fund of Jiangsu Province(BK20220061)the Fellowship of China Postdoctoral Science Foundation(2021M702382)。
文摘Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis.
基金supported by the National Natural Science Foundation of China(U21A20332,52103226,52202275,52203314,and 12204253)the Distinguished Young Scholars Fund of Jiangsu Province(BK20220061)the Fellowship of China Postdoctoral Science Foundation(2021 M702382)。
文摘As an alternative to conventional energy conversion and storage reactions,gas-involved electrochemical reactions,including the carbon dioxide reduction reaction(CO_(2)RR),nitrogen reduction reaction(NRR)and hydrogen evolution reaction(HER),have become an emerging research direction and have gained increasing attention due to their advantages of environmental friendliness and sustainability.Various studies have been designed to accelerate sluggish kinetics but with limited results.Most of them promote the reaction by modulating the intrinsic properties of the catalyst,ignoring the synergistic effect of the reaction as a whole.Due to the introduction of gas,traditional liquid-solid two-phase reactions are no longer applicable to future research.Since gas-involved electrochemical reactions mostly occur at the junctions of gaseous reactants,liquid electrolytes and solid catalysts,the focus of future research on reaction kinetics should gradually shift to three-phase reaction interfaces.In this review,we briefly introduce the formation and constraints of the three-phase interface and propose three criteria to judge its merit,namely,the active site,mass diffusion and electron mass transfer.Subsequently,a series of modulation methods and relevant works are discussed in detail from the three improvement directions of‘exposing more active sites,promoting mass diffusion and accelerating electron transfer’.Definitively,we provide farsighted insights into the understanding and research of three-phase interfaces in the future and point out the possible development direction of future regulatory methods,hoping that this review can broaden the future applications of the three-phase interface,including but not limited to gas-involved electrochemical reactions.
基金the National Natural Science Foundation of China(Grant Nos.61705070 and 61974052)China Postdoctoral Science Foundation(Grant Nos.2019M662594)National Research Foundation of Korea(NRF)Grant funded by the Korean Government(MSIP)(Nos.NRF2019R1A2C4069438 and NRF2018R1A6A1A03025242)。
文摘Light confinement induced by spontaneous near-surface resonance is inherently determined by the location and geometry of metallic nanostructures(NSs),offering a facile and effective approach to break through the limitation of the light-mater interaction within the photoactive layers.Here,we demonstrate high-performance Al NS/ZnO quantum dots(Al/ZnO) heterostructure UV photodetectors with controllable morphologies of the self-assembled Al NSs.The Al/ZnO heterostructures exhibit a superior light utilization than the ZnO/Al heterostructures,and a strong morphological dependence of the Al NSs on the optical properties of the heterostructures.The inter-diffusion of Al atoms into ZnO matrixes is of a great benefit for the carrier transportation.Consequently,the optimal photocurrent of the Al/ZnO heterostructure photodetectors is significantly increased by 275 times to ~1.065 mA compared to that of the pristine ZnO device,and an outstanding photoresponsivity of 11.98 A W-1 is correspondingly achieved under 6.9 MW cm-2 UV light illumination at 10 V bias.In addition,a relatively fast response is similarly witnessed with the Al/ZnO devices,paving a path to fabricate the high-performance UV photodetectors for applications.
基金the Science and Technology Project of Changsha City(No.kq2004038)Program for Innovative Leading Talents for Science and Technology of Xianyang City。
文摘Lonicerae Flos(LF)derived from the dried flower buds or opening flowers of four Lonicera plants(Lonicera macranthoides,L.hypoglauca,L.confusa,and L.fulvotnetosa),is a popular traditional Chinese medicine.Because the four origin plants are very similar in morphology,it is difficult to control the quality of LF in actual production.Over the past decade,many reports have pointed out the differences among them,including the botanical characteristics and active ingredients.However,there is still a lack of rapid methods that can be applied to the identification of the four origins.In this study,comparative analysis of the four chloroplast genomes was performed,and they showed low diversity(Pi=0.00267),three variation hotspots regions(rbcL-accD,rps12-ndhF and rps12-trnN-trnG)were identified as potentially molecular marker of highly informative.Meanwhile,the most obvious difference in SSR comparative analysis is reverse and complement repeats were only identified in L.confusa and L.hypoglauca,respectively.Lastly,the phylogenetic tree showed that L.confusa is more closely related to L.fulvotnetosa,while L.macranthoides is closer to L.hypoglauca.This study systematically revealed the differences among the four chloroplast genomes,and it provides valuable genetic information for identifying the origin of LF.
文摘Currently,the only central bank digital currencies(CBDC)in the world is Venezuela^currency^Petro.Nowadays,the IMF,BIS,and major countries have conducted a lot of research on CBDC.It's an urgent issue for the central bank to issue CBDC,determine and formulate the circulation of CBDC and the issuance speed,and supervise it.Therefore,establishing ARMA and VARs by sorting out literature,the paper uses the characteristics of CBDC—cash,and similarities with third-party payment in terms of payment to determine the circulation of CDBC by third-party payment users and currency in circulation.The model calculates and predicts the speed of circulation of digital currency.The issuance of CBDC will accelerate the circulation of money.In this regard,we will explore the impact of money supply on monetary policy and make relevant recommendations.
文摘The micro crack of aluminum sheet during cold rolling lubricated with emulsions is investigated. Experi-ments show that micro cracks occur after cold rolling process and this is attributed to various parameters, for instance, the thin oxide film formed at the sheet surface. The micro crack spacing thus becomes an important parameter which deserves more concerns. The aspect ratio of these micro cracks is then analyzed theoreti-cally, which takes into consideration of the oxide fracture process. The good agreement between the obser-vations and the theoretical predictions validates the analysis. The approach can shed some new lights on the mechanical process of aluminium sheet during cold rolling.
基金supported by the National Natural Science Foundation of China(Nos.U21A20332,52103226,and 52071226)the Outstanding Youth Foundation of Jiangsu Province(No.BK20220061)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20201171)the Key Research and Development Plan of Jiangsu Province(No.BE2020003-3)the Fellowship of China Postdoctoral Science Foundation(No.2021M702382).
文摘Nitrogen chemisorption is a prerequisite for efficient ammonia synthesis under ambient conditions,but promoting this process remains a significant challenge.Here,by loading yttrium clusters onto a single-atom support,an electronic promoting effect is triggered to successfully eliminate the nitrogen chemisorption barrier and achieve highly efficient ammonia synthesis.Density functional theory calculations reveal that yttrium clusters with abundant electron orbitals can provide considerable electrons and greatly promote electron backdonation to the N2 antibonding orbitals,making the chemisorption process exothermic.Moreover,according to the“hot atom”mechanism,the energy released during exothermic N2 chemisorption would benefit subsequent N2 cleavage and hydrogenation,thereby dramatically reducing the energy barrier of the overall process.As expected,the proof-of-concept catalyst achieves a prominent NH3 yield rate of 48.1μg·h^(−1)·mg^(−1)at−0.2 V versus the reversible hydrogen electrode,with a Faradaic efficiency of up to 69.7%.This strategy overcomes one of the most serious obstacles for electrochemical ammonia synthesis,and provides a promising method for the development of catalysts with high catalytic activity and selectivity.
基金supported by the National Key R&D Program of China(No.2021YFA0715502)the National Natural Science Foundation of China(Nos.61974052,and 61904065)+2 种基金the Innovation Project of Optics Valley Laboratory(No.OVL2021BG009)the Fund from Science,Technology and Innovation Commission of Shenzhen Municipality(No.GJHZ20210705142540010)the Fundamental Research Funds for the Central Universities(WUT:2022IVA055).
文摘Infrared(IR)solar cells are promising devices for improving the power conversion efficiency(PCE)of conventional solar cells by expanding the utilization region of the sunlight spectrum to near-infrared range.IR solar cells based on colloidal quantum dots(QDs)have attracted extensive attention due to the widely tunable absorption spectrum controlled by dot size and the unique solution processibility.However,the trade-off in QD solar cells between light absorption and photo-generated carrier collection has limited the further improvement of PCE.Here,we present high-performance PbS QD IR solar cells resulting from the combination of boosted light absorption and optimized carrier extraction.By constructing an optical resonance cavity,the light absorption is significantly enhanced in the range of 1,150–1,300 nm at a relatively thin photoactive layer.Meanwhile,the thin photoactive layer facilitates efficient carrier extraction.Consequently,the PbS QD IR solar cells exhibit a highly efficient photoelectric conversion in the IR region,resulting in a high IR PCE of 1.3%which is comparable to the highest value of solution-processed IR solar cells based on PbSe QDs.These results demonstrate that constructing an optical resonance cavity is a reasonable strategy for effective conversion of photons in the devices aiming at light in a relatively narrow wavelength range,such as IR solar cells and narrow band photodetectors.
基金supported by a grant fromthe International Cooperationthe National Natural Science Foundation of China(30721140554)
文摘Single nucleotide polymorphism (SNP) is a common form of genetic variation and popularly exists in maize genome. An Illumina GoldenGate assay with 1 536 SNP markers was used to genotype maize inbred lines and identified the functional genetic variations underlying drought tolerance by association analysis. Across 80 lines, 1 006 polymorphic SNPs (65.5% of the total) in the assay with good call quality were used to estimate the pattern of genetic diversity, population structure, and familial relatedness. The analysis showed the best number of fixed subgroups was six, which was consistent with their original sources and results using only simple sequence repeat markers. Pairwise linkage disequilibrium (LD) and association mapping with phenotypic traits investigated under water-stressed and well-watered regimes showed rapid LD decline within 100-500 kb along the physical distance of each chromosome, and that 29 SNPs were associated with at least two phenotypic traits in one or more environments, which were related to drought-tolerant or drought-responsive genes. These drought-tolerant SNPs could be converted into functional markers and then used for maize improvement by marker-assisted selection.
基金supported by the National Natural Science Foundation of China(No.31701791)National Science Foundation of China(NSFC)-Henan Joint major grant(No.U2004206)+1 种基金the State Key Laboratory of Cotton Biology(No.CB2020A06)the USDA National Institute of Food and Agriculture Hatch Project(No.ARZT-1370680-R31-R31-172).
文摘Insects utilize xenobiotic compounds to up-and downregulate cytochrome P450 monooxygenases(P450s)involved in detoxification of toxic xenobiotics including phytochemicals and pesticides.G-quadruplexes(G4)-forming DNA motifs are enriched in the promoter regions of transcription factors and function as cis-acting elements to regulate these genes.Whether and how P450s gain and keep G4 DNA motifs to regulate their expression still remain unexplored.Here,we show that CYP321A1,a xenobiotic-metabolizing P450 from Helicoverpa zea,a polyphagous insect of economic importance,has acquired and preserved a G4 DNA motif by selectively retaining a transposon known as HzIS1-3 that carries this G4 DNA motif in its promoter region.The HzIS1-3 G4 DNA motif acts as a silencer to suppress the constitutive and induced expression of CYP321A1 by plant allelochemicals flavone and xanthotoxin through folding into an intramolecular parallel or hybrid-1 conformation in the absence or presence of K^(+).The G4 ligand N-methylmesoporphyrin IX(NMM)strengthens the silencing effect of HzIS1-3 G4 DNA motif by switching its structure from hybrid-1 to hybrid-2.The enrichment of transposons in P450s and other environment-adaptation genes implies that selective retention of G4 DNA motif-carrying transposons may be the main evolutionary route for these genes to obtain G4 DNA motifs.
基金supported by the Key Deployment Project of Centre for Ocean Mega-Research of Science, Chinese Academy of Sciences (No. COMS2019J08)the Guangzhou Municipal Science and Technology Project (No. 201904010291)+1 种基金National Natural Science Foundation of China (No. 21806042)Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety (No. 2019B030301008)。
文摘The passive sampling technique, diffusive gradients in thin films(DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per-and polyfluoroalkyl substances(PFAS). However, its effectiveness has been questioned because of the small effective sampling area(3.1 cm^(2)). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area(27 cm^(2)) and as a result lower method quantification limits(0.15 –0.21 ng/L for one-day deployment and 0.02 – 0.03 ng/L for one-week deployment) and much higher(by > 10 factors) sampling rate(100 m L/day) compared to the standard DGT(piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling(500m L). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.
