Seed size is an important agronomic trait in melons that directly affects seed germination and subsequent seedling growth.However,the genetic mechanism underlying seed size in melon remains unclear.In the present stud...Seed size is an important agronomic trait in melons that directly affects seed germination and subsequent seedling growth.However,the genetic mechanism underlying seed size in melon remains unclear.In the present study,we employed Bulked-Segregant Analysis sequencing(BSA-seq)to identify a candidate region(~1.35 Mb)on chromosome 6 that corresponds to seed size.This interval was confirmed by QTL mapping of three seed size-related traits from an F2 population across three environments.This mapping region represented nine QTLs that shared an overlapping region on chromosome 6,collectively referred to as qSS6.1.New InDel markers were developed in the qSS6.1 region,narrowing it down to a 68.35 kb interval that contains eight annotated genes.Sequence variation analysis of the eight genes identified a SNP with a C to T transition mutation in the promoter region of MELO3C014002,a leucine-rich repeat receptor-like kinase(LRR-RLK)gene.This mutation affected the promoter activity of the MELO3C014002 gene and was successfully used to differentiate the large-seeded accessions(C-allele)from the small-seeded accessions(T-allele).qRT-PCR revealed differential expression of MELO3C014002 between the two parental lines.Its predicted protein has typical LRR-RLK family domains,and phylogenetic analyses reveled its similarity with the homologs in several plant species.Altogether,these findings suggest MELO3C014002 as the most likely candidate gene involved in melon seed size regulation.Our results will be helpful for better understanding the genetic mechanism regulating seed size in melons and for genetically improving this important trait through molecular breeding pathways.展开更多
Au-Ag alloy nanoparticles with different cavity sizes have great potential for improving photocatalytic performance due to their tunable plasmon effect.In this study,galvanic replacement was combined with co-reduction...Au-Ag alloy nanoparticles with different cavity sizes have great potential for improving photocatalytic performance due to their tunable plasmon effect.In this study,galvanic replacement was combined with co-reduction with the reaction kinetics processes regulated to rapidly synthesize Au-Ag hollow alloy nanoparticles with tunable cavity sizes.The position of the localized surface plasmon resonance(LSPR)peak could be effectively adjusted between 490 nm and 713 nm by decreasing the cavity size of the Au-Ag hollow nanoparticles from 35 nm to 20 nm.The plasmon-enhanced photocatalytic H2 evolution of alloy nanoparticles with different cavity sizes was investigated.Compared with pure P25(TiO2),intact and thin-shelled Au-Ag hollow nanoparticles(HNPs)-supported photocatalyst exhibited an increase in the photocatalytic H2 evolution rate from 0.48μmol h^−1 to 4μmol h^−1 under full-spectrum irradiation.This improved photocatalytic performance was likely due to the plasmon-induced electromagnetic field effect,which caused strong photogenerated charge separation,rather than the generation of hot electrons.展开更多
The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays as...The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.展开更多
Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium ox...Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.展开更多
Trade-offs between survival and growth are widely observed in plants.Melon is an annual,trailing herb that produces economically valuable fruits that are traditionally cultivated in early spring in China.Melon seedlin...Trade-offs between survival and growth are widely observed in plants.Melon is an annual,trailing herb that produces economically valuable fruits that are traditionally cultivated in early spring in China.Melon seedlings are sensitive to low temperatures,and thus usually suffer from cold stress during the early growth period.However,little is known about the mechanism behind the trade-offs between seedling cold tolerance and fruit quality in melon.In this study,a total of 31 primary metabolites were detected from the mature fruits of eight melon lines that differ with respect to seedling cold tolerance;these included 12 amino acids,10 organic acids,and 9 soluble sugars.Our results showed that concentrations of most of the primary metabolites in the cold-resistant melons were generally lower than in the cold-sensitive melons;the greatest difference in metabolite levels was observed between the cold-resistant line H581 and the moderately cold-resistant line HH09.The metabolite and transcriptome data for these two lines were then subjected to weighted correlation network analysis,resulting in the identification of five key candidate genes underlying the balancing between seedling cold tolerance and fruit quality.Among these genes,CmEAF7 might play multiple roles in regulating chloroplast development,photosynthesis,and the ABA pathway.Furthermore,multi-method functional analysis showed that CmEAF7 can certainly improve both seedling cold tolerance and fruit quality in melon.Our study identified an agriculturally important gene,CmEAF7,and provides a new insight into breeding methods to develop melon cultivars with seedling cold tolerance and high fruit quality.展开更多
Complete replacement of aromatic carbon bonds in graphene by carbyne chains gives rise to supergraphene whose mechanical properties are expected to depend on its structure. However, this dependence is to date unclear....Complete replacement of aromatic carbon bonds in graphene by carbyne chains gives rise to supergraphene whose mechanical properties are expected to depend on its structure. However, this dependence is to date unclear. In this paper, explicit expressions for the in-plane stiffness and Poisson＇s ratio of supergraphene are obtained using a molecular mechanics model. The theoretical results show that the in-plane stiffness of supergraphene is drastically（at least one order） smaller than that of graphene, whereas its Poisson＇s ratio is higher than 0.5. As the index number increases（i.e., the length of carbyne chains increases and the bond density decreases）, the in-plane stiffness of supergraphene decreases while the Poisson＇s ratio increases. By analyzing the relation among the layer modulus, in-plane stiffness and Poisson＇s ratio, it is revealed that the mechanism of the faster decrease in the in-plane stiffness than the bond density is due to the increase of Poisson＇s ratio. These findings are useful for future applications of supergraphene in nanomechanical systems.展开更多
ZnSe as a surface passivation layer in quantum dot-sensitized solar cells plays an important role in preventing charge recombination and thus improves the power conversion efficiency(PCE).However, as a wide bandgap se...ZnSe as a surface passivation layer in quantum dot-sensitized solar cells plays an important role in preventing charge recombination and thus improves the power conversion efficiency(PCE).However, as a wide bandgap semiconductor, ZnSe cannot efficiently absorb and convert long-wavelength light.Doping transition metal ions into ZnSe semiconductors is an effective way to adjust the band gap, such as manganese ions.In this paper, it is found by the method of density functional theory calculation that the valence band of ZnSe moves upward with manganese ions doping, which leads to acceleration of charge separation, wider light absorption range, and enhancing light harvesting.Finally, by using ZnSe doped with manganese ions as the passivation layer, the TiO2/CdS/CdSe co-sensitized solar cell has a PCE of 6.12%, and the PCE of the solar cell increases by 9% compared with the undoped one(5.62%).展开更多
BACKGROUND MET fusion is a key driver mutation,but it is rare in gastric cancer(GC).Several MET(hepatocyte growth factor receptor)inhibitors have been approved for the treatment of MET-positive patients,but the tumor ...BACKGROUND MET fusion is a key driver mutation,but it is rare in gastric cancer(GC).Several MET(hepatocyte growth factor receptor)inhibitors have been approved for the treatment of MET-positive patients,but the tumor response is heterogeneous.With the development of next-generation sequencing,diverse MET fusion partner genes have been identified.We herein report a fusion variant involving KIF5BMET in GC.CASE SUMMARY After thoracoscopic inferior lobectomy plus lymph node dissection under general anesthesia,a“tumor within a tumor”was found in the lung tumor tissue of a 64-year-old non-smoking male patient.Combining the medical history and the results of enzyme labeling,the focal area was considered to be GC.To seek potential therapeutic regimens,an intergenic region between KIF5B and MET fusion was identified.This fusion contains a MET kinase domain and coil-coiled domains encoded by KIF5B exons 1-25,which might drive the oncogenesis.CONCLUSION Our finding could extend the spectrum and genomic landscape of MET fusions in GC and favor the development of personalized therapy.展开更多
Single-junction and tandem perovskite solar cells(PSCs)have achieved impressive power conversion efficiencies(PCEs)of 25.7%and 31.3%,respectively,which makes it to be one of next-generation photovoltaic technologies[1...Single-junction and tandem perovskite solar cells(PSCs)have achieved impressive power conversion efficiencies(PCEs)of 25.7%and 31.3%,respectively,which makes it to be one of next-generation photovoltaic technologies[1−9].Inter-face engineering[3,5,10−12],composition engineering[13]and ad-ditive engineering[7,14,15]have made remarkable contribu-tions to efficiency enhancement.Compared with efficiency,the long-term operational stability of PSCs jogs along,which is far from the requirements of commercialization.Currently,almost all regular n-i-p PSCs were accomplished with classic-al organic hole-transport materials(HTMs),i.e.,PTAA[16]and spiro-OMeTAD[2,4,6].However,the highly efficient PSCs with the above organic hole-transport layers(HTL)usually suffer from instability.To facilitate hole transport and extraction,LiTF-SI and tBP are frequently employed to dope organic HTLs but this would sacrifice device stability.The use of these hygro-scopic p-dopants endows the devices with poor moisture sta-bility.展开更多
Strict control of powder properties,especially particle size distribution(PSD),is critical in the laser powder bed fusion(LPBF)process to ensure the quality of the fabricated parts.This work shows that reducing the po...Strict control of powder properties,especially particle size distribution(PSD),is critical in the laser powder bed fusion(LPBF)process to ensure the quality of the fabricated parts.This work shows that reducing the powder size could improve the ductility of LPBF fabricated AlSi10Mg.The tensile elongation increased from 4.1%to 8.8%when AlSi10Mg powder sizes(D50 value)decreased from 76μm to 16μm in the as-fabricated state.Our results showed that fine powder size stimulates epitaxial grain growth due to excessive remelting.The presence of epitaxial columnar grains makes the crack path across inner melt pools more frequent and travels from the coarse melt pool zones to the fine melt pool zones.This work suggests that powder size is a crucial factor to be considered in maintaining repeatable mechanical properties in LPBF processes,particularly when ductility and ductility-dominated properties are critical.展开更多
The microstructure and mechanical properties of 304 L stainless steel fabricated by selective laser melting are investigated in this study.With the optimized laser processing parameters,a relative density of 99.9%is a...The microstructure and mechanical properties of 304 L stainless steel fabricated by selective laser melting are investigated in this study.With the optimized laser processing parameters,a relative density of 99.9%is achieved with fine austenite grains and nanoscale cellular subgrains in size of approximately 0.5μm.The presence ofδ-ferrite andσphase precipitates is identified by the x-ray diffraction and transmission electron microscopy.Moreover,the microstructure is identified as an austenite matrix with about 4%δ-ferrite and a trace amount ofσphase by using electron backscattered diffraction analysis.These smallσphase particles are mainly distributed along austenite grain boundaries.Furthermore,the presence of nanoscale cellular subgrains contributes to the good tensile strength and ductility of the selective laser melted 304 L,along with precipitate strengthening and strain hardening.Tensile property anisotropy is also identified in this 304 L,which is attributed to the microstructure difference on vertical and horizontal planes.展开更多
For zinc air batteries,a non-noble metal-based electrocatalyst with a high performance and stability in oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is imperative in application.Herein,a catalyst ba...For zinc air batteries,a non-noble metal-based electrocatalyst with a high performance and stability in oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is imperative in application.Herein,a catalyst based on FeCo-N encapsuled in nitrogen-doped carbon nanotubes has been prepared,which provides an implementable method to design controlled structures with excellent bifunction al electrocatalytic activities.By adjusting the molar ratio of two metals,the synthesized FeCo-N-C catalyst delivers a competitive ORR and OER performance compared with commercial Pt/C and IrO_(2),performing a low overvoltage gap between ORR(E_(1/2))and OER(E_(j=10))of 0.8 V.Moreover,as a promising cathode in zinc air battery,the FeCo-N-C catalyst possesses an affirmative stability of over 100 h and large power density(129 mW·cm^(-2)).This work demonstrates that FeCo-N-C is one of the most promising catalysts for zinc air batteries and provides a possibility for exploration of batteries with high stability by adjusting the molar ratio of metals in the catalysts.展开更多
Rainwater and run-off from three kinds of impervious surface in the Shanghai urban area,China were sampled.Polycyclic aromatic hydrocarbons(PAHs) were measured in the samples,and their sources were assessed.The mean s...Rainwater and run-off from three kinds of impervious surface in the Shanghai urban area,China were sampled.Polycyclic aromatic hydrocarbons(PAHs) were measured in the samples,and their sources were assessed.The mean sum of the 16 PAH concentrations measured in rainwater and run-offs from ceramic tiles,asphalt roofs,and asphalt roads were 873,1404,1743,and 4023 ng/L,respectively.The PAH concentrations found in this study were moderate compared to PAH concentrations found in run-offs in other studies.The main PAH components in the rainwater,roof run-off,and asphalt road run-off samples were 3-ring PAHs,3–4-ring PAHs,and 4–6-ring PAHs,respectively.Source apportionment results indicated that combustion(47.4%–55.5%) and vehicular emissions(30.5%–33.0%) were the major contributors to PAHs in roof run-off.Vehicular emissions were the most significant contributors to asphalt road run-off(47.2%),followed by combustion(23.5%),and petroleum(16.3%).Vehicular emissions and coal and natural gas combustion are therefore the most significant sources of PAHs in run-off from impervious surfaces in the Shanghai urban area.展开更多
It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions.In this work,we report an efficient and stable NiCo_(2...It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions.In this work,we report an efficient and stable NiCo_(2)S_(4)/N,S co-doped reduced graphene oxide(NCS/NS-rGO)electrocatalyst for water splitting,in which NCS microspheres are composed of one-dimentional(1D)nanorods grown homogeneously on the surface of NS-rGOs).The synergetic effect,abundant active sites,and hybridization of NCS/NS-rGO endow their outstanding electrocatalytic performance for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in both alkaline and neutral conditions.Furthermore,NCS/NS-rGO employed as both anode and cathode in a two-electrode alkaline and neutral system electrolyzers deliver 10 mA/cm^(2) with the low cell voltage of 1.58 V in alkaline and 1.91 V in neutral condition.These results illustrate the rational design of carbon-supported nickel-cobalt based bifunctional materials for practical water splitting over a wide pH range.展开更多
Developing high efficiency and low cost electrocatalysts is critical for the enhancement of oxygen reduction reaction(ORR),which is the fundamental for the development and commercialization of renewable energy convers...Developing high efficiency and low cost electrocatalysts is critical for the enhancement of oxygen reduction reaction(ORR),which is the fundamental for the development and commercialization of renewable energy conversion technology.Herein,zinc-nitrogen-carbon(Zn-N-C)was prepared by using biomass resource chitosan via a facile carbon bath method.The obtained Zn-N-C delivered a high specific surface area(794.7 cm^2/g)together with pore volume(0.49 cm^3/g).During the electrochemical evaluation of oxygen reduction reaction(ORR),Zn-N-C displayed high activity for ORR with an onset pote ntial E0=0.96 VRHE and a half wave potential E1/2=0.86 VRHE,which were more positive than those of the comme rcial 20 wt%Pt/C benchmark catalyst(E0=0.96 VRHE and E1/2=0.81 VRHE).In addition,the ZnN-C catalyst also had a better stability and methanol tolerance than those of the Pt/C catalyst.展开更多
The influence of heat treatment holding temperatures from 600 to 1300℃ on the microstructure,mechanical properties and corrosion resistance in selective laser melted(SLMed)304L stainless steel is investigated in this...The influence of heat treatment holding temperatures from 600 to 1300℃ on the microstructure,mechanical properties and corrosion resistance in selective laser melted(SLMed)304L stainless steel is investigated in this work.The results reveal that there is no remarkable microstructure change after holding at 600℃ for 2 h,while recrystallization leads to a slight decrease in grain size in the temperature range of 700–900℃.The heat treatment at temperatures from 1000 to 1300℃ for 2 h obviously affects the morphology of grains in SLMed 304L stainless steel.Combining effects of grain coarsening,delta-ferrite(δ)phases reduction and residual stress release during heat treatment lead to the reduction of yield strength and an increasing elongation.The elongation of the samples heat treated at 800℃ for 2 h is,however,significantly decreased due to the increase in the amount of sigma(σ)phase.A remarkable increase in the amount ofδferrite results in an increase in yield strength but a decrease in ductility after heat treatment at 1300℃ for 2 h.The corrosion resistance of the samples heat treated at 1300℃ is significantly improved due to the substantial reduction of brittle phase(σ).There is no obvious effect of the presence ofδferrite on corrosion behavior.展开更多
The abundancy of defect sinks in the microstructure of laser powder bed fusion(LPBF) processed austenitic stainless steels was found to be beneficial for helium resistance.In the current study,the influence of the nov...The abundancy of defect sinks in the microstructure of laser powder bed fusion(LPBF) processed austenitic stainless steels was found to be beneficial for helium resistance.In the current study,the influence of the novel microstructure in LPBF processed 304 L on the helium bubble growth behaviour was investigated using transmission electron microscopy in samples implanted with He^(+) ion and post-irradiation annealing treated at 600℃ for 1 h.Two variants of LPBF processed 304 L samples were used,one in as-built condition and the other solution-annealed.The comparison between the two samples indicated that the helium bubble growth was inhibited and remained stable in the as-built sample but coarsened significantly in the solution-annealed sample.The sub-grain boundaries and oxide nano-inclusions acted as defect sinks to trap helium atoms and inhibited the growth of helium bubble in the as-built sample under the post-irradiation annealing conditions used.展开更多
基金the Henan Special Funds for Major Science and Technology,China(221100110400)the Henan Scienti?c and Technological Joint Project for Agricultural Improved Varieties,China(2022010503)the National Natural Science Foundation of China(31902038 and 32072564)。
文摘Seed size is an important agronomic trait in melons that directly affects seed germination and subsequent seedling growth.However,the genetic mechanism underlying seed size in melon remains unclear.In the present study,we employed Bulked-Segregant Analysis sequencing(BSA-seq)to identify a candidate region(~1.35 Mb)on chromosome 6 that corresponds to seed size.This interval was confirmed by QTL mapping of three seed size-related traits from an F2 population across three environments.This mapping region represented nine QTLs that shared an overlapping region on chromosome 6,collectively referred to as qSS6.1.New InDel markers were developed in the qSS6.1 region,narrowing it down to a 68.35 kb interval that contains eight annotated genes.Sequence variation analysis of the eight genes identified a SNP with a C to T transition mutation in the promoter region of MELO3C014002,a leucine-rich repeat receptor-like kinase(LRR-RLK)gene.This mutation affected the promoter activity of the MELO3C014002 gene and was successfully used to differentiate the large-seeded accessions(C-allele)from the small-seeded accessions(T-allele).qRT-PCR revealed differential expression of MELO3C014002 between the two parental lines.Its predicted protein has typical LRR-RLK family domains,and phylogenetic analyses reveled its similarity with the homologs in several plant species.Altogether,these findings suggest MELO3C014002 as the most likely candidate gene involved in melon seed size regulation.Our results will be helpful for better understanding the genetic mechanism regulating seed size in melons and for genetically improving this important trait through molecular breeding pathways.
基金supported by the National Natural Science Foundation of China(No.61704114)the Key areas of Science and Technology Program of Xinjiang Production and Construction Corps,China(No.2018AB004)the National Science Foundation(CBET-1803256).
文摘Au-Ag alloy nanoparticles with different cavity sizes have great potential for improving photocatalytic performance due to their tunable plasmon effect.In this study,galvanic replacement was combined with co-reduction with the reaction kinetics processes regulated to rapidly synthesize Au-Ag hollow alloy nanoparticles with tunable cavity sizes.The position of the localized surface plasmon resonance(LSPR)peak could be effectively adjusted between 490 nm and 713 nm by decreasing the cavity size of the Au-Ag hollow nanoparticles from 35 nm to 20 nm.The plasmon-enhanced photocatalytic H2 evolution of alloy nanoparticles with different cavity sizes was investigated.Compared with pure P25(TiO2),intact and thin-shelled Au-Ag hollow nanoparticles(HNPs)-supported photocatalyst exhibited an increase in the photocatalytic H2 evolution rate from 0.48μmol h^−1 to 4μmol h^−1 under full-spectrum irradiation.This improved photocatalytic performance was likely due to the plasmon-induced electromagnetic field effect,which caused strong photogenerated charge separation,rather than the generation of hot electrons.
基金This work was supported by the Natural Science Foundation of China(51962032,61704114,and 51764049)the Youth Innovative Talents Cultivation Fund,Shihezi University(KX01480109)the Opening Project of The Research Center for Material Chemical Engineering Technology of Xinjiang Bingtuan(2017BTRC007).
文摘The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.
基金the Shenyang University of Technology(QNPY202209-4)the Key R&D project of Liaoning Province of China(2020JH2/10300079)+2 种基金the“Liaoning BaiQianWan Talents Program”(2018921006)the Liaoning Revitalization Talents Program(XLYC1908034)the National Natural Science Foundation of China(21571132).
文摘Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.
基金Thisworkwas supported by the National Natural Science Foundation of China(Grant numbers 31872101 and 32072564)the Henan Special Funds for Major Science and Technology(221100110400)+1 种基金the Excellent Youth Foundation of Henan Scientific Committee(222300420009)the Foundation for Young Talents of Henan Agricultural University(30500728).
文摘Trade-offs between survival and growth are widely observed in plants.Melon is an annual,trailing herb that produces economically valuable fruits that are traditionally cultivated in early spring in China.Melon seedlings are sensitive to low temperatures,and thus usually suffer from cold stress during the early growth period.However,little is known about the mechanism behind the trade-offs between seedling cold tolerance and fruit quality in melon.In this study,a total of 31 primary metabolites were detected from the mature fruits of eight melon lines that differ with respect to seedling cold tolerance;these included 12 amino acids,10 organic acids,and 9 soluble sugars.Our results showed that concentrations of most of the primary metabolites in the cold-resistant melons were generally lower than in the cold-sensitive melons;the greatest difference in metabolite levels was observed between the cold-resistant line H581 and the moderately cold-resistant line HH09.The metabolite and transcriptome data for these two lines were then subjected to weighted correlation network analysis,resulting in the identification of five key candidate genes underlying the balancing between seedling cold tolerance and fruit quality.Among these genes,CmEAF7 might play multiple roles in regulating chloroplast development,photosynthesis,and the ABA pathway.Furthermore,multi-method functional analysis showed that CmEAF7 can certainly improve both seedling cold tolerance and fruit quality in melon.Our study identified an agriculturally important gene,CmEAF7,and provides a new insight into breeding methods to develop melon cultivars with seedling cold tolerance and high fruit quality.
基金supported by the National Natural Science Foundation of China(Grant 11425209)Shanghai Pujiang Program(Grant 13PJD016)
文摘Complete replacement of aromatic carbon bonds in graphene by carbyne chains gives rise to supergraphene whose mechanical properties are expected to depend on its structure. However, this dependence is to date unclear. In this paper, explicit expressions for the in-plane stiffness and Poisson＇s ratio of supergraphene are obtained using a molecular mechanics model. The theoretical results show that the in-plane stiffness of supergraphene is drastically（at least one order） smaller than that of graphene, whereas its Poisson＇s ratio is higher than 0.5. As the index number increases（i.e., the length of carbyne chains increases and the bond density decreases）, the in-plane stiffness of supergraphene decreases while the Poisson＇s ratio increases. By analyzing the relation among the layer modulus, in-plane stiffness and Poisson＇s ratio, it is revealed that the mechanism of the faster decrease in the in-plane stiffness than the bond density is due to the increase of Poisson＇s ratio. These findings are useful for future applications of supergraphene in nanomechanical systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61376011,61704114,51402141,and 61604086)the Gansu Provincial Natural Science Foundation,China(Grant No.17JR5RA198)+2 种基金the Fundamental Research Funds for the Central Universities,China(Grant Nos.lzujbky-2018-119 and lzujbky-2018-ct08)the Fund from Shenzhen Science and Technology Innovation Committee,China(Grant No.JCYJ20170818155813437)the Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps(Grant No.2018AB004)
文摘ZnSe as a surface passivation layer in quantum dot-sensitized solar cells plays an important role in preventing charge recombination and thus improves the power conversion efficiency(PCE).However, as a wide bandgap semiconductor, ZnSe cannot efficiently absorb and convert long-wavelength light.Doping transition metal ions into ZnSe semiconductors is an effective way to adjust the band gap, such as manganese ions.In this paper, it is found by the method of density functional theory calculation that the valence band of ZnSe moves upward with manganese ions doping, which leads to acceleration of charge separation, wider light absorption range, and enhancing light harvesting.Finally, by using ZnSe doped with manganese ions as the passivation layer, the TiO2/CdS/CdSe co-sensitized solar cell has a PCE of 6.12%, and the PCE of the solar cell increases by 9% compared with the undoped one(5.62%).
文摘BACKGROUND MET fusion is a key driver mutation,but it is rare in gastric cancer(GC).Several MET(hepatocyte growth factor receptor)inhibitors have been approved for the treatment of MET-positive patients,but the tumor response is heterogeneous.With the development of next-generation sequencing,diverse MET fusion partner genes have been identified.We herein report a fusion variant involving KIF5BMET in GC.CASE SUMMARY After thoracoscopic inferior lobectomy plus lymph node dissection under general anesthesia,a“tumor within a tumor”was found in the lung tumor tissue of a 64-year-old non-smoking male patient.Combining the medical history and the results of enzyme labeling,the focal area was considered to be GC.To seek potential therapeutic regimens,an intergenic region between KIF5B and MET fusion was identified.This fusion contains a MET kinase domain and coil-coiled domains encoded by KIF5B exons 1-25,which might drive the oncogenesis.CONCLUSION Our finding could extend the spectrum and genomic landscape of MET fusions in GC and favor the development of personalized therapy.
基金supported by the National Natural Science Foundation of China(62274018)the Fundamental Research Funds for the Central Universities(2020CDJ-LHZZ-074)+4 种基金the Natural Science Foundation of Chongqing(cstc2020jcyj-msxmX0629)the Support Plan for Overseas Students to Return to China for Entrepreneurship and Innovation(cx2020003)L.Ding thanks the National Key Research and Development Program of China(2022YFB3803300)the open research fund of Songshan Lake Materials Laboratory(2021SLABFK02)the National Natural Science Foundation of China(21961160720).
文摘Single-junction and tandem perovskite solar cells(PSCs)have achieved impressive power conversion efficiencies(PCEs)of 25.7%and 31.3%,respectively,which makes it to be one of next-generation photovoltaic technologies[1−9].Inter-face engineering[3,5,10−12],composition engineering[13]and ad-ditive engineering[7,14,15]have made remarkable contribu-tions to efficiency enhancement.Compared with efficiency,the long-term operational stability of PSCs jogs along,which is far from the requirements of commercialization.Currently,almost all regular n-i-p PSCs were accomplished with classic-al organic hole-transport materials(HTMs),i.e.,PTAA[16]and spiro-OMeTAD[2,4,6].However,the highly efficient PSCs with the above organic hole-transport layers(HTL)usually suffer from instability.To facilitate hole transport and extraction,LiTF-SI and tBP are frequently employed to dope organic HTLs but this would sacrifice device stability.The use of these hygro-scopic p-dopants endows the devices with poor moisture sta-bility.
文摘Strict control of powder properties,especially particle size distribution(PSD),is critical in the laser powder bed fusion(LPBF)process to ensure the quality of the fabricated parts.This work shows that reducing the powder size could improve the ductility of LPBF fabricated AlSi10Mg.The tensile elongation increased from 4.1%to 8.8%when AlSi10Mg powder sizes(D50 value)decreased from 76μm to 16μm in the as-fabricated state.Our results showed that fine powder size stimulates epitaxial grain growth due to excessive remelting.The presence of epitaxial columnar grains makes the crack path across inner melt pools more frequent and travels from the coarse melt pool zones to the fine melt pool zones.This work suggests that powder size is a crucial factor to be considered in maintaining repeatable mechanical properties in LPBF processes,particularly when ductility and ductility-dominated properties are critical.
基金supported financially by the National Key R&D Program of China(Nos.2018 YFB1106100)the Special funds for Future Industries of Shenzhen(Project No.JSGG20170824104916638)。
文摘The microstructure and mechanical properties of 304 L stainless steel fabricated by selective laser melting are investigated in this study.With the optimized laser processing parameters,a relative density of 99.9%is achieved with fine austenite grains and nanoscale cellular subgrains in size of approximately 0.5μm.The presence ofδ-ferrite andσphase precipitates is identified by the x-ray diffraction and transmission electron microscopy.Moreover,the microstructure is identified as an austenite matrix with about 4%δ-ferrite and a trace amount ofσphase by using electron backscattered diffraction analysis.These smallσphase particles are mainly distributed along austenite grain boundaries.Furthermore,the presence of nanoscale cellular subgrains contributes to the good tensile strength and ductility of the selective laser melted 304 L,along with precipitate strengthening and strain hardening.Tensile property anisotropy is also identified in this 304 L,which is attributed to the microstructure difference on vertical and horizontal planes.
基金financially supported by Gansu Provincial Natural Science Foundation of China(Nos.17JR5RA198,2020HZ-2)the Cooperation project of Gansu Academy of Sciences(No.2020HZ-2)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2018-119,lzujbky-2018-ct08,lzujbky-2019-it23)the Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps(No.2018AB004)。
文摘For zinc air batteries,a non-noble metal-based electrocatalyst with a high performance and stability in oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is imperative in application.Herein,a catalyst based on FeCo-N encapsuled in nitrogen-doped carbon nanotubes has been prepared,which provides an implementable method to design controlled structures with excellent bifunction al electrocatalytic activities.By adjusting the molar ratio of two metals,the synthesized FeCo-N-C catalyst delivers a competitive ORR and OER performance compared with commercial Pt/C and IrO_(2),performing a low overvoltage gap between ORR(E_(1/2))and OER(E_(j=10))of 0.8 V.Moreover,as a promising cathode in zinc air battery,the FeCo-N-C catalyst possesses an affirmative stability of over 100 h and large power density(129 mW·cm^(-2)).This work demonstrates that FeCo-N-C is one of the most promising catalysts for zinc air batteries and provides a possibility for exploration of batteries with high stability by adjusting the molar ratio of metals in the catalysts.
基金supported by the National Key Technology R&D Program of China(No.2010BAK69B16-1)the Shanghai Commission of Science and Technology(No.10dz1200402),China
文摘Rainwater and run-off from three kinds of impervious surface in the Shanghai urban area,China were sampled.Polycyclic aromatic hydrocarbons(PAHs) were measured in the samples,and their sources were assessed.The mean sum of the 16 PAH concentrations measured in rainwater and run-offs from ceramic tiles,asphalt roofs,and asphalt roads were 873,1404,1743,and 4023 ng/L,respectively.The PAH concentrations found in this study were moderate compared to PAH concentrations found in run-offs in other studies.The main PAH components in the rainwater,roof run-off,and asphalt road run-off samples were 3-ring PAHs,3–4-ring PAHs,and 4–6-ring PAHs,respectively.Source apportionment results indicated that combustion(47.4%–55.5%) and vehicular emissions(30.5%–33.0%) were the major contributors to PAHs in roof run-off.Vehicular emissions were the most significant contributors to asphalt road run-off(47.2%),followed by combustion(23.5%),and petroleum(16.3%).Vehicular emissions and coal and natural gas combustion are therefore the most significant sources of PAHs in run-off from impervious surfaces in the Shanghai urban area.
基金supported by the National Natural Science Foundation of China(Nos.51962032,61704114,and 51764049)the Youth Innovative Talents Cultivation Fund,Shihezi University(No.KX01480109)the Opening Project of The Research Center for Material Chemical Engineering Technology of Xinjiang Bingtuan(No.2017BTRC007).
文摘It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions.In this work,we report an efficient and stable NiCo_(2)S_(4)/N,S co-doped reduced graphene oxide(NCS/NS-rGO)electrocatalyst for water splitting,in which NCS microspheres are composed of one-dimentional(1D)nanorods grown homogeneously on the surface of NS-rGOs).The synergetic effect,abundant active sites,and hybridization of NCS/NS-rGO endow their outstanding electrocatalytic performance for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in both alkaline and neutral conditions.Furthermore,NCS/NS-rGO employed as both anode and cathode in a two-electrode alkaline and neutral system electrolyzers deliver 10 mA/cm^(2) with the low cell voltage of 1.58 V in alkaline and 1.91 V in neutral condition.These results illustrate the rational design of carbon-supported nickel-cobalt based bifunctional materials for practical water splitting over a wide pH range.
基金supported by the National Natural Science Foundation of China(No.21865025)。
文摘Developing high efficiency and low cost electrocatalysts is critical for the enhancement of oxygen reduction reaction(ORR),which is the fundamental for the development and commercialization of renewable energy conversion technology.Herein,zinc-nitrogen-carbon(Zn-N-C)was prepared by using biomass resource chitosan via a facile carbon bath method.The obtained Zn-N-C delivered a high specific surface area(794.7 cm^2/g)together with pore volume(0.49 cm^3/g).During the electrochemical evaluation of oxygen reduction reaction(ORR),Zn-N-C displayed high activity for ORR with an onset pote ntial E0=0.96 VRHE and a half wave potential E1/2=0.86 VRHE,which were more positive than those of the comme rcial 20 wt%Pt/C benchmark catalyst(E0=0.96 VRHE and E1/2=0.81 VRHE).In addition,the ZnN-C catalyst also had a better stability and methanol tolerance than those of the Pt/C catalyst.
基金sponsored by the National Natural Science Foundation of China(Grant No.52073176)the special funds for International Research on Science and Technology of Shenzhen(Project No.GJHZ2020073109520311).
文摘The influence of heat treatment holding temperatures from 600 to 1300℃ on the microstructure,mechanical properties and corrosion resistance in selective laser melted(SLMed)304L stainless steel is investigated in this work.The results reveal that there is no remarkable microstructure change after holding at 600℃ for 2 h,while recrystallization leads to a slight decrease in grain size in the temperature range of 700–900℃.The heat treatment at temperatures from 1000 to 1300℃ for 2 h obviously affects the morphology of grains in SLMed 304L stainless steel.Combining effects of grain coarsening,delta-ferrite(δ)phases reduction and residual stress release during heat treatment lead to the reduction of yield strength and an increasing elongation.The elongation of the samples heat treated at 800℃ for 2 h is,however,significantly decreased due to the increase in the amount of sigma(σ)phase.A remarkable increase in the amount ofδferrite results in an increase in yield strength but a decrease in ductility after heat treatment at 1300℃ for 2 h.The corrosion resistance of the samples heat treated at 1300℃ is significantly improved due to the substantial reduction of brittle phase(σ).There is no obvious effect of the presence ofδferrite on corrosion behavior.
基金sponsored by the National Natural Science Foundation of China(Grant No.52073176)。
文摘The abundancy of defect sinks in the microstructure of laser powder bed fusion(LPBF) processed austenitic stainless steels was found to be beneficial for helium resistance.In the current study,the influence of the novel microstructure in LPBF processed 304 L on the helium bubble growth behaviour was investigated using transmission electron microscopy in samples implanted with He^(+) ion and post-irradiation annealing treated at 600℃ for 1 h.Two variants of LPBF processed 304 L samples were used,one in as-built condition and the other solution-annealed.The comparison between the two samples indicated that the helium bubble growth was inhibited and remained stable in the as-built sample but coarsened significantly in the solution-annealed sample.The sub-grain boundaries and oxide nano-inclusions acted as defect sinks to trap helium atoms and inhibited the growth of helium bubble in the as-built sample under the post-irradiation annealing conditions used.
