1. Introduction The requirements for the performance of materials have become increasingly stringent in recent years, with the rapid development of aerospace, machinery, metallurgy, nuclear energy,chemical industry, a...1. Introduction The requirements for the performance of materials have become increasingly stringent in recent years, with the rapid development of aerospace, machinery, metallurgy, nuclear energy,chemical industry, and military industry [1,2], and traditional single-phase materials are gradually revealing disadvantages due to the contradiction between demanding service environments and simple material design.展开更多
Grain-boundary（GB） structures are commonly imaged as discrete atomic columns, yet the chemical modifications are gradual and extend into the adjacent lattices, notably the space charge, hence the two-dimensional def...Grain-boundary（GB） structures are commonly imaged as discrete atomic columns, yet the chemical modifications are gradual and extend into the adjacent lattices, notably the space charge, hence the two-dimensional defects may also be treated as continuum changes to extended interfacial structure. This review presents a spatially-resolved analysis by electron energy-loss spectroscopy of the GB chemical structures in a series of SrTiO3 bicrystals and a ceramic, using analytical electron microscopy of the pre-Cs-correction era. It has identified and separated a transient layer at the model Σ5 grain-boundaries（GBs） with characteristic chemical bonding, extending the continuum interfacial approach to redefine the GB chemical structure. This GB layer has evolved under segregation of iron dopant, starting from subtle changes in local bonds until a clear transition into a distinctive GB chemistry with substantially increased titanium concentration confined within the GB layer in 3-unit cells, heavily strained, and with less strontium. Similar segregated GB layer turns into a titania-based amorphous film in SrTiO3 ceramic, hence reaching a more stable chemical structure in equilibrium with the intergranular Ti2O3 glass also. Space charge was not found by acceptor doping in both the strained Σ5 and amorphous GBs in SrTiO3 owing to the native transient nature of the GB layer that facilitates the transitions induced by Fe segregation into novel chemical structures subject to local and global equilibria. These GB transitions may add a new dimension into the structure–property relationship of the electronic materials.展开更多
Nucleation behavior of amorphous Si–B–C–N ceramics derived from boron-modified polyvinylsilazane procusors was systematically investigated by transmission electron microscopy(TEM) combined with spatially-resolved e...Nucleation behavior of amorphous Si–B–C–N ceramics derived from boron-modified polyvinylsilazane procusors was systematically investigated by transmission electron microscopy(TEM) combined with spatially-resolved electron energy-loss spectroscopy(EELS) analysis. The ceramics were pyrolyzed at1000℃ followed by further annealing in N2, and SiC nano-crystallites start to emerge at 1200℃ and dominate at 1500℃. Observed by high-angle annular dark-field imaging, bright and dark clusters were revealed as universal nano-structured features in ceramic matrices before and after nucleation, and the growth of cluster size saturated before reaching 5 nm at 1400℃. EELS analysis demonstrated the gradual development of bonding structures successively into SiC, graphetic BNCxand Si3N4 phases, as well as a constant presence of unexpected oxygen in the matrices. Furthermore, EELS profiling revealed the bright SiC clusters and less bright Si3N4-like clusters at 1200–1400℃. Since the amorphous matrix has already phase separated into SiCN and carbon clusters, another phase separation of SiCN into SiC and Si3N4-like clusters might occur by annealing to accompany their nucleation and growth, albeit one crystallized and another remained in amorphous structure. Hinderance of the cluster growth and further crystallization was owing to the formation of BNCxlayers that developed between SiC and Si3N4-like clusters as well as from the excessive oxygen to form the stable SiO2.展开更多
To solve the volume expansion and poor electrical conductivity of germanium-based anode materials,Ge/rGO/CNTs nanocomposites with three-dimensional network structure are fabricated through the dispersion of polyethyle...To solve the volume expansion and poor electrical conductivity of germanium-based anode materials,Ge/rGO/CNTs nanocomposites with three-dimensional network structure are fabricated through the dispersion of polyethylene-polypropylene glycol(F127)and reduction of hydrogen.An interesting phenomenon is discovered that F127 can break GeO_(2)polycrystalline microparticles into 100 nm nanoparticles by only physical interaction,which promotes the uniform dispersion of GeO_(2)in a carbon network structure composed of graphene(rGO)and carbon nanotubes(CNTs).As evaluated as anode material of Lithium-ion batteries,Ge/rGO/CNTs nanocomposites exhibit excellent lithium storage performance.The initial specific capacity is high to 1549.7 mAh/g at 0.2 A/g,and the reversible capacity still retains972.4 mAh/g after 100 cycles.The improved lithium storage performance is attributed to that Ge nanoparticles can effectively slow down the volume expansion during charge and discharge processes,and threedimensional carbon networks can improve electrical conductivity and accelerate lithium-ion transfer of anode materials.展开更多
Strontium titanate(SrTiO_(3))is a thermoelectric material with large Seebeck coefficient that has potential applications in high-temperature power generators.To simultaneously achieve a low thermal conductivity and hi...Strontium titanate(SrTiO_(3))is a thermoelectric material with large Seebeck coefficient that has potential applications in high-temperature power generators.To simultaneously achieve a low thermal conductivity and high electrical conductivity,polycrystalline SrTiO_(3)with a multi-scale architecture was designed by the co-doping with lanthanum,cerium,and niobium.High-quality nano-powders were synthesized via a hydrothermal method.Nano-inclusions and a nano/micro-sized second phase precipitated during sintering to form mosaic crystal-like and epitaxial-like structures,which decreased the thermal conductivity.Substituting trivalent Ce and/or La with divalent Sr and substituting pentavalent Nb with tetravalent Ti enhanced the electrical conductivity without decreasing the Seebeck coefficient.By optimizing the dopant type and ratio,a low thermal conductivity of 2.77 W·m^(-1)·K^(-1)and high PF of 1.1 mW·m^(-1)·K^(-2)at 1000 K were obtained in the sample co-doped with 5-mol%La,5-mol%Ce,and 5-mol%Nb,which induced a large ZT of 0.38 at 1000 K.展开更多
The magnetic compensation of aeromagnetic survey is an important calibration work,which has a great impact on the accuracy of measurement.In an aeromagnetic survey flight,measurement data consists of diurnal variation...The magnetic compensation of aeromagnetic survey is an important calibration work,which has a great impact on the accuracy of measurement.In an aeromagnetic survey flight,measurement data consists of diurnal variation,aircraft maneuver interference field,and geomagnetic field.In this paper,appropriate physical features and the modular feedforward neural network(MFNN)with Levenberg-Marquard(LM)back propagation algorithm are adopted to supervised learn fluctuation of measuring signals and separate the interference magnetic field from the measurement data.LM algorithm is a kind of least square estimation algorithm of nonlinear parameters.It iteratively calculates the jacobian matrix of error performance and the adjustment value of gradient with the regularization method.LM algorithm’s computing efficiency is high and fitting error is very low.The fitting performance and the compensation accuracy of LM-MFNN algorithm are proved to be much better than those of TOLLES-LAWSON(T-L)model with the linear least square(LS)solution by fitting experiments with five different aeromagnetic surveys’data.展开更多
In reactive-hot-pressed ZrB_(2)-SiC-ZrC ceramics,ZrO_(2) was found to replace ZrC phase,hence leading to confusion in designing ultra-high-temperature ceramics(UHTCs).We employ high-precision X-ray diffraction and ele...In reactive-hot-pressed ZrB_(2)-SiC-ZrC ceramics,ZrO_(2) was found to replace ZrC phase,hence leading to confusion in designing ultra-high-temperature ceramics(UHTCs).We employ high-precision X-ray diffraction and electron microscopies to reassess the phase behavior during entire reaction and densification and to reveal the evolution of multiphase relationship at different stages before reaching the final ZrB2-SiC-ZrO_(2) composition.Frozen from transient liquid-phase,bulk glassy phase of 15 vol% was found to be constituted of Zr-Si-B-C-O with stable Zr:O ratio,which starts as early as in the intermediate stage to suppress ZrC in favor of SiC nucleation.Inhomogeneity in phase relations and microstructures results from variation in local transient liquid-phase to develop SiC phase in various modes and rates.As inferred from the earlier report of phase formation,competing reactions for ZrC and ZrB_(2) phases in the initial stage below 1000℃ were mediated via Zr-O-B-C liquid phase.Such liquid phase was moderated by stable B-O components,as initiated from surface oxides of starting powders.This picture under a continuous mother liquid phase can unify the reactions and sintering into a collective meltingenucleationegrowth process,which enables and guides the evolution of multiphase relationship through several stages to reach final densification at relatively low temperature with the help of residual oxides.展开更多
High dielectric constant can be reached in a reductive-sintered Sr_(1-x)Ba_(x)TiO_(3)barrier-layer capacitor with core‒rim structures as dominant microstructural features.By SEM and aberration-corrected TEM observatio...High dielectric constant can be reached in a reductive-sintered Sr_(1-x)Ba_(x)TiO_(3)barrier-layer capacitor with core‒rim structures as dominant microstructural features.By SEM and aberration-corrected TEM observations,an interfacial zone between the core and rim,named as white-rim(w-rim),was found always enriched with Ba,while the core was free of Ba solution.The reductive liquid-phase sintering resulted in three times the concentrations of oxygen vacancies(VO)into cores and rims compared to their A-site vacancies(VA),while enabling the highest concentration of VO(~17%)without VA in w-rim.The strained core/w-rim interfaces,with obvious interfacial polarizations,which can effectively raise the dielectric constant,were expected to be created from a temporary equilibrium between the cores and the liquidphase.The synergetic evolution of core‒rim structures,SreO vacancies,multiple internal polarized structures can be utilized to better control and optimize dielectric behaviors and other functionalities for perovskite capacitors and other multi-functional ceramics.展开更多
To study the effects of growing rice （Oryza sativa L.） leaves under the treatment of the short-term elevated CO2 during the period of sink-source transition, several physiological processes such as dynamic changes i...To study the effects of growing rice （Oryza sativa L.） leaves under the treatment of the short-term elevated CO2 during the period of sink-source transition, several physiological processes such as dynamic changes in photosynthesis, photosynthate accumulation, enzyme activities （sucrose phosphate synthase （SPS）, and sucrose synthase （SS））, and their specific gene （spsl and RSusl） expressions in both mature and developing leaf were measured. Rice seedlings with fully expanded sixth leaf （marked as the source leaf, L6） were kept in elevated （700 μmol/mol） and ambient （350 mol/L） CO2 until the 7th leaf （marked as the sink leaf, L7） fully expanded. The results demonstrated that elevated CO2 significantly increased the rate of leaf elongation and biomass accumulation of L7 during the treatment without affecting the growth of L6. However, in both developing and mature leaves, net photosynthetic assimilation rate （A）, all kinds of photosynthate contents such as starch, sucrose and hexose, activities of SPS and SS and transcript levels of spsl and RSusl were significantly increased under elevated CO2 condition. Results suggested that the elevated CO2 had facilitated photosynthate assimilation, and increased photosynthate supplies from the source leaf to the sink leaf, which accelerated the growth and sink-source transition in new developing sink leaves. The mechanisms of SPS regulation by the elevated CO2 was also discussed.展开更多
For energy storage system,it is still a huge challenge to achieve high energy density and high power density simultaneously.One potential solution is to fabricate electrochemical capacitors(ECs),which store electric e...For energy storage system,it is still a huge challenge to achieve high energy density and high power density simultaneously.One potential solution is to fabricate electrochemical capacitors(ECs),which store electric energy through surface ion adsorption or redox reactions.Here we report a new electrode material,heavy nitrogen-doped(9.29 at.%)black titania(TiO2-x:N).This unique hybrid material,consisting of conductive amorphous shells supported on nanocrystalline cores,has rapid N-mediated redox reaction(TiO2-xNy+zH++ze■-TiO2-xNyHz),especially in acidic solutions,providing a specific capacitance of 750 Fg-1at 2 m V s-1(707 Fg-1at 1 A g-1),great rate capability(503 F g-1at 20 Ag-1),and maintain stable after initial fading.Being a new developed supercapacitor material,nitrogen-doped black titania may revive the oxide-based supercapacitors.展开更多
Phase relation and microstructure evolution in the pressure-less sintered TiB_(2)‒TiC ceramics preceded with mechanical alloying were systematically studied by a combination of SEM analysis.WC debris from milling ball...Phase relation and microstructure evolution in the pressure-less sintered TiB_(2)‒TiC ceramics preceded with mechanical alloying were systematically studied by a combination of SEM analysis.WC debris from milling balls promotes sintering by dissolving into the TiC phase to achieve dense microstructures at 1600℃.Variation of W solution in TiC grains exposes two types of core-rim structures,with no or more W in dark and white cores respectively but with common medium W in both rims.Diminishing whitecores reveal an exchange reaction between WC and TiC via mechanical alloying to form the Ti_(1-z)W_(z)C phase prior to sintering.The dark-cores inherit from the as-milled TiC power to further enable the reprecipitation of rims from a mixed liquid-phase,which facilitated also the anisotropic growth of TiB_(2) grains.The dark-cores grow persistently in the second-step at 2000℃ enabled by this liquid-phase,which coarsens the TiB2 grains too.With more alloyed phase,sintering was insufficient at 1500℃ with only the surface fluidity from the primary powders,and the second-step sintering increased the fluidity in the liquid-phase to fully densify the binary microstructure.Re-distribution of the alloyed W by two-step sintering rationalizes the evolution process of the binary microstructures and leads to better understanding of the mechanical behaviors.展开更多
Core-rim structures were identified as a common feature in hot-pressed ZrB2-SiC-MC ceramics(M=Nb,Hf,Ta and W)by a combination of X-ray diffraction,scanning and transmission electron microscopies.Quantitative analyses ...Core-rim structures were identified as a common feature in hot-pressed ZrB2-SiC-MC ceramics(M=Nb,Hf,Ta and W)by a combination of X-ray diffraction,scanning and transmission electron microscopies.Quantitative analyses associate them with the bi-solubility of M in ZrB2 phase,in which transition of solubility across the core/rim boundary is abrupted,signifying their creation via dissolution-reprecipitation process facilitated by transient liquid-phase.The cores were retained from starting powder after surface melting and the rims were grown from the liquid-phase to incorporate more solutes,leaving the residual liquid to turn into ZrC phase with higher solubility of M.We propose g-point scheme in the ZrB2-MB2 diagrams to combine the bi-solubility and the core-rim structures into an intra-phase relationship created by sintering,leading further to a hierarchical phase relationship.The temperature dependence of flexural strength in the ZrB2-SiC-MC ceramics varies with MC additions,which can be respectively strengthened by the strain energy created in the core-rim structures and metal segregation to grain boundaries.展开更多
To achieve a better material for thermoelectric power generation device, filled skutterudite Yb0.3 Co_4 Sb_(12) samples were fabricated by melting-quenching-annealing-spark plasma sintering(SPS)method. Two sets of sam...To achieve a better material for thermoelectric power generation device, filled skutterudite Yb0.3 Co_4 Sb_(12) samples were fabricated by melting-quenching-annealing-spark plasma sintering(SPS)method. Two sets of samples, before and after SPS, were investigated. In both the two sets of samples,the average grain size of the samples increases monotonously with the increase of annealing time,while Yb filling fraction firstly increases and then decreases. Yb not filling into the skutterudite remains at the grain boundaries in the form of Yb_2 O_3 after SPS, which could be quantified by the spatially difference method of energy dispersive spectra. Step distribution of Yb filling fraction was observed in the samples annealed for 1 h, which was caused by the microstructural evolution from the peritectic phases to the skutterudite phase. The sample annealed for 3 days and SPS sintered possesses the maximum value of Yb filling fraction 0.249 and the maximum ZT value of 1.24 at 850 K. These results are helpful to better understand the microstructural evolution and Yb filling behavior in skutterudite materials.展开更多
To achieve a better material for uncooled infrared (IR) detector, polycrystalline VO2(B) thin films with layered W-doping were fabricated on Si substrates by magnetron sputtering, and the best temperature coefficient ...To achieve a better material for uncooled infrared (IR) detector, polycrystalline VO2(B) thin films with layered W-doping were fabricated on Si substrates by magnetron sputtering, and the best temperature coefficient of resistance (TCR) value reached -4.1%/K. The film synthesis was in a two-step route, first deposition at room temperature and then post-deposition annealing at 450 ℃, to better control the crystallization behavior. Various transmission electron microscopy (TEM) methods were employed to investigate three sets of multi-layered films with different deposition time, 10, 20, and 30 min, with especial emphasis on the effect of layered W-doping scheme on the formation of multiple VO2(B) layers. Spatial-resolved energy dispersive X-ray spectroscopy (EDS) revealed the alternative patterns of W-rich layers and W-poor layers, while the thinner films exhibited better crystallinity and texturing. By comparison with an as-deposited film, it was found that the inter-diffusion between the two types of layers was completed in the deposition step while both remained in amorphous structure. A stable W solution of about 8 cat% in VO2(B) layers measured from all these films indicated that the layered doping can tailor the multi-layered microstructure to optimize the performance of VO2(B) films.展开更多
Similar to Si_(3)N_(4)ceramics,β→a phase transformation in SiC ceramics plays a key role in tailoring the microstructures thus optimizing related properties.SiC microstructures are dominated with the core erim struc...Similar to Si_(3)N_(4)ceramics,β→a phase transformation in SiC ceramics plays a key role in tailoring the microstructures thus optimizing related properties.SiC microstructures are dominated with the core erim structures by AlN-solution,and by EBSD analysis,a-lamellae were revealed as stacking-faults(SF)and twin-boundaries(TB)in b-grains,co-existing with the coreerim structures asα/β→α’/β’transformation by sintering.The structural transformation can proceed much further by gas-pressuresintering than hot-pressing with only RE2O3 agents,while the latter retain a high-density of SF/TB in the metastable b-SiC grains.By high-angle secondary-electron imaging,nanoscale transition-layer(TL)was observed as an inter-phase to fully separate the core and rim,which is created by a transitory equilibrium in the solutionereprecipitation process.The enrichment of AlN or RE in TL demonstrates their segregation to core surface until reaching the super-saturation and before the growth of rims.With higher AlN or RE solution and after sintering,a shear stress can develop from TL contour to drive the expansion of SF/TB in Martensitic transition,especially under an external isotropic pressure.The combinations ofβ→a transformation,coreerim structures and viscous liquid-phase enable the comprehensive assessment of sintering-microstructure-property-performance relationship of SiC ceramics,as demonstrated for their creep behaviors and fracture toughness.展开更多
Background： The pathogenicity of cleft lip （CL） is pretty complicated since it is influenced by the interaction of environment and genetic factors. The purpose of this study was to conduct a genome-wide screening o...Background： The pathogenicity of cleft lip （CL） is pretty complicated since it is influenced by the interaction of environment and genetic factors. The purpose of this study was to conduct a genome-wide screening of aberrant methylation loci in partial lesion tissues of patients with nonsyndromic CL （NSCL） and preliminarily validate candidate dysmethylated genes associated with NSCL.Methods： Fifteen healthy and sixteen NSCL fetal lip tissue samples were collected. The Infinium HumanMethylation450 BeadChip was used to screen aberrant methylation loci in three NSCL and three healthy lip tissues. The differential methylation sites and functions of the annotated genes between NSCL and healthy lip tissues were analyzed using minfi package of R software, cluster analysis, Gene Ontology （GO） annotation, and metabolic pathway annotation. Gene expression was assessed in nine differentially methylated genes by real-time polymerase chain reaction （PCR）. The transcriptions mRNA levels of three out of nine candidate genes were downregulated remarkably in NSCL lip tissues, and these three genes＇ abnormal methylation loci were validated by pyrosequencing in 16 NSCL cases and 15 healthy cases.Results： In total, 4879 sites in the genes of NSCL odinopoeia fetuses showed aberrant methylation when compared with normal lip tissue genome. Among these, 3661 sites were hypermethylated and 1218 sites were hypomethylated as compared to methylation levels in healthy specimens. These aberrant methylation sites involved 2849 genes and were widely distributed among the chromosomes. Most differentially methylated sites were located in cytosine-phosphoric acid-guanine islands. Based on GO analysis, aberrantly methylated genes were involved in 11 cellular components, 13 molecular functions, and a variety of biological processes. Notably, the transcription of DAB1, REELIN, and FYN was significantly downregulated in lesion tissues of NSCL fetus （P 〈 0.05）. Pyrosequencing results validated that there were two loci in DABI with high methylation status in patient tissues （P 〈 0.05）. Conclusions： We detected numerous aberrantly methylated loci in lesion tissues of NSCL fetus. Aberrant gene expression in the REELIN signaling pathway might be related with NSCL. Decreased transcription of DAB1, a member of REELIN signal pathway, resulted from its abnormal high methylation, which might be one of the factors underlying the occurrence of NSCL.展开更多
A novel solid polymer electrolyte with comb-like structure is prepared via a solvent-free UV-cured method.The relationship between conductivity and molecular weight is investigated and revealed.The optimal electrolyte...A novel solid polymer electrolyte with comb-like structure is prepared via a solvent-free UV-cured method.The relationship between conductivity and molecular weight is investigated and revealed.The optimal electrolyte presents a considerably high conductivity of 1.44·10^(-4)S·cm^(-1)at 30℃.Meanwhile,it shows excellent compatibility with metallic lithium and wide electrochemical window(>5 V).To investigate the safety and cycling performance,the coin cell and soft package battery are assembled respectively.The LiFePO_(4)/Li coin cells exhibit initial discharge specific capacities of 163.2,147.7,137.3 and 108.7 mA·h·g^(-1)at 0.1,0.2,0.5 and 1C under 60℃,respectively.Notably,when the coin cells work at 30℃,the initial discharge specific capacities at 0.05,0.1,0.2 and 0.5C are 140.5,133.5,107.7 and 55.6 mA·h·g^(-1).Significantly,a 3.5 cm×7 cm solid-state soft pack battery is fabricated and cycling at 30℃.The first discharge capacity reaches to 137.5 mA·h·g^(-1)and the capacity retention is as high as 84.4%after 100 cycles at 0.2C and remain 95.5%after 100 cycles at 0.5C,respectively.These results shows a promising solid polymer electrolyte for solid-state batteries with good cycling and safety performance.展开更多
Correlated phase and microstructural evolution are systematically investigated by electron microscopies in Sr-deficient Sr(Ti,Nb)O_(3)(STNO)thermoelectric ceramics incorporated with different fraction of reduced graph...Correlated phase and microstructural evolution are systematically investigated by electron microscopies in Sr-deficient Sr(Ti,Nb)O_(3)(STNO)thermoelectric ceramics incorporated with different fraction of reduced graphene oxide(RGO).It is found that while no impurity except for very few Ti_(3)O_(5) precipitates are observed in monolithic STNO,the Nb-enriched rutile TiO_(2) appears in RGO/STNO composites.With increasing RGO content,the amount of precipitates increase at first and then decrease when RGO content becomes high,which can be ascribed to the formation of local Magneli phase.In addition,the energy-dispersive X-ray spectra combined with cathodoluminescence characterization indicates that the variation of Sr deficiency experiences the opposite trend with respect to the precipitates content.These findings clearly reveal the unique reducing effect of RGO on the microstructure of doped SrTiO_(3) with Sr deficiency,which can greatly facilitate the design of perovskite based thermoelectric materials of hierarchical structure.展开更多
The A2B2O7 series of ternary oxides are derivatives of fluorite structure over a wide range of rA/rB.Competing by two rare-earths the A-site,La2-xLuxZr2O7 ceramics were found transparent only in pore-free microstructu...The A2B2O7 series of ternary oxides are derivatives of fluorite structure over a wide range of rA/rB.Competing by two rare-earths the A-site,La2-xLuxZr2O7 ceramics were found transparent only in pore-free microstructures with similar grain sizes of pyrochlore(PY)and defective fluorite(DF)phases.Mutual solubilities of Lu and La in both phases were found by imaging and energy-dispersive spectroscopy analysis in scanning electron microscope.The dual-phase microstructures were developed with liquid-phase resulted from the exothermal reactions,creating a miscibility gap between two structures to moderate their competing grain growth.Change in grain growth behaviors in liquid-phase is described by a nucleation line in La2Zr2O7-Lu2Zr2O7 phase diagram.Variations of solution levels in DF grains and co-existing of dual-phase grain clusters in common orientation were revealed in transparent ceramics by electron backscattered diffraction,resulted by epitaxial relation of two phases promoted by the liquid-phase.Oxygen vacancies and various hole states common in both phases were revealed by characteristic cathodoluminescence peaks.The collective effects of pores,phase and grain boundaries,oxygen vacancies on scattering or absorption of visible light enables to establish a hierarchical microstructure-transparency relationship in such complex oxide ceramics,which could be tailored or further optimized by controllable sintering.展开更多
Phytophthora pathogens secrete numerous apoplastic effectors to manipulate host immunity.Herein,we identified a polysaccharide lyase 1 protein,PsPL1,which acts as an essential virulence factor of P.sojae infection in ...Phytophthora pathogens secrete numerous apoplastic effectors to manipulate host immunity.Herein,we identified a polysaccharide lyase 1 protein,PsPL1,which acts as an essential virulence factor of P.sojae infection in soybean.However,the overexpression of PsPL1 in P.sojae reduced infection and triggered enhanced immune responses in soybean.PsPL1 exhibited pectin lyase activity and degraded plant pectin to generate pectin oligosaccharides(POSs)with a polymerization degree of 3–14,exhibiting different levels of acetylation and methylation modifications.PsPL1 and the degraded pectin products triggered immune responses in soybean and different Solanaceous plants.The PsPL1-triggered immune responses required RSPL1,a membrane-localized leucine-rich repeat receptor-like protein,which is essential for Phytophthora resistance.Conversely,the PsPL1-degraded product-triggered immune responses depended on the membrane-localized lysin motif receptor-like kinase CERK1.This study reveals that the pectin lyase exhibits a dual immunogenic role during P.sojae infection,which activates plant resistance through different immune receptors and provides novel insights into the function of pectin lyase in host-pathogen interactions.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51872061,52032002,51972081)Heilongjiang Touyan Team Program。
文摘1. Introduction The requirements for the performance of materials have become increasingly stringent in recent years, with the rapid development of aerospace, machinery, metallurgy, nuclear energy,chemical industry, and military industry [1,2], and traditional single-phase materials are gradually revealing disadvantages due to the contradiction between demanding service environments and simple material design.
基金supported by the National Natural Science Foundation of China(Grant No.51532006)the Fund from Shanghai Municipal Science and Technology Commission(Grant No.16DZ2260600)+1 种基金the 111 Project of the Ministry of Educationthe Fund from the National Bureau of Foreign Experts(Project No.D16002)
文摘Grain-boundary（GB） structures are commonly imaged as discrete atomic columns, yet the chemical modifications are gradual and extend into the adjacent lattices, notably the space charge, hence the two-dimensional defects may also be treated as continuum changes to extended interfacial structure. This review presents a spatially-resolved analysis by electron energy-loss spectroscopy of the GB chemical structures in a series of SrTiO3 bicrystals and a ceramic, using analytical electron microscopy of the pre-Cs-correction era. It has identified and separated a transient layer at the model Σ5 grain-boundaries（GBs） with characteristic chemical bonding, extending the continuum interfacial approach to redefine the GB chemical structure. This GB layer has evolved under segregation of iron dopant, starting from subtle changes in local bonds until a clear transition into a distinctive GB chemistry with substantially increased titanium concentration confined within the GB layer in 3-unit cells, heavily strained, and with less strontium. Similar segregated GB layer turns into a titania-based amorphous film in SrTiO3 ceramic, hence reaching a more stable chemical structure in equilibrium with the intergranular Ti2O3 glass also. Space charge was not found by acceptor doping in both the strained Σ5 and amorphous GBs in SrTiO3 owing to the native transient nature of the GB layer that facilitates the transitions induced by Fe segregation into novel chemical structures subject to local and global equilibria. These GB transitions may add a new dimension into the structure–property relationship of the electronic materials.
基金financially supported by National Natural Science Foundation of China (Grant Nos. 51172255 and 51532006)
文摘Nucleation behavior of amorphous Si–B–C–N ceramics derived from boron-modified polyvinylsilazane procusors was systematically investigated by transmission electron microscopy(TEM) combined with spatially-resolved electron energy-loss spectroscopy(EELS) analysis. The ceramics were pyrolyzed at1000℃ followed by further annealing in N2, and SiC nano-crystallites start to emerge at 1200℃ and dominate at 1500℃. Observed by high-angle annular dark-field imaging, bright and dark clusters were revealed as universal nano-structured features in ceramic matrices before and after nucleation, and the growth of cluster size saturated before reaching 5 nm at 1400℃. EELS analysis demonstrated the gradual development of bonding structures successively into SiC, graphetic BNCxand Si3N4 phases, as well as a constant presence of unexpected oxygen in the matrices. Furthermore, EELS profiling revealed the bright SiC clusters and less bright Si3N4-like clusters at 1200–1400℃. Since the amorphous matrix has already phase separated into SiCN and carbon clusters, another phase separation of SiCN into SiC and Si3N4-like clusters might occur by annealing to accompany their nucleation and growth, albeit one crystallized and another remained in amorphous structure. Hinderance of the cluster growth and further crystallization was owing to the formation of BNCxlayers that developed between SiC and Si3N4-like clusters as well as from the excessive oxygen to form the stable SiO2.
基金financially supported by National Natural Science Foundation of China(Nos.22379056,52102100)Industry foresight and common key technology research in Carbon Peak and Carbon Neutrality Special Project from Zhenjiang city(No.CG2023003)Research and Practice Innovation Plan of Postgraduate Training Innovation Project in Jiangsu Province(No.SJCX23_2164)。
文摘To solve the volume expansion and poor electrical conductivity of germanium-based anode materials,Ge/rGO/CNTs nanocomposites with three-dimensional network structure are fabricated through the dispersion of polyethylene-polypropylene glycol(F127)and reduction of hydrogen.An interesting phenomenon is discovered that F127 can break GeO_(2)polycrystalline microparticles into 100 nm nanoparticles by only physical interaction,which promotes the uniform dispersion of GeO_(2)in a carbon network structure composed of graphene(rGO)and carbon nanotubes(CNTs).As evaluated as anode material of Lithium-ion batteries,Ge/rGO/CNTs nanocomposites exhibit excellent lithium storage performance.The initial specific capacity is high to 1549.7 mAh/g at 0.2 A/g,and the reversible capacity still retains972.4 mAh/g after 100 cycles.The improved lithium storage performance is attributed to that Ge nanoparticles can effectively slow down the volume expansion during charge and discharge processes,and threedimensional carbon networks can improve electrical conductivity and accelerate lithium-ion transfer of anode materials.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51702168 and 51532006).
文摘Strontium titanate(SrTiO_(3))is a thermoelectric material with large Seebeck coefficient that has potential applications in high-temperature power generators.To simultaneously achieve a low thermal conductivity and high electrical conductivity,polycrystalline SrTiO_(3)with a multi-scale architecture was designed by the co-doping with lanthanum,cerium,and niobium.High-quality nano-powders were synthesized via a hydrothermal method.Nano-inclusions and a nano/micro-sized second phase precipitated during sintering to form mosaic crystal-like and epitaxial-like structures,which decreased the thermal conductivity.Substituting trivalent Ce and/or La with divalent Sr and substituting pentavalent Nb with tetravalent Ti enhanced the electrical conductivity without decreasing the Seebeck coefficient.By optimizing the dopant type and ratio,a low thermal conductivity of 2.77 W·m^(-1)·K^(-1)and high PF of 1.1 mW·m^(-1)·K^(-2)at 1000 K were obtained in the sample co-doped with 5-mol%La,5-mol%Ce,and 5-mol%Nb,which induced a large ZT of 0.38 at 1000 K.
基金National key special projects for major scientific instruments and equipment development(2017YFF0107400)。
文摘The magnetic compensation of aeromagnetic survey is an important calibration work,which has a great impact on the accuracy of measurement.In an aeromagnetic survey flight,measurement data consists of diurnal variation,aircraft maneuver interference field,and geomagnetic field.In this paper,appropriate physical features and the modular feedforward neural network(MFNN)with Levenberg-Marquard(LM)back propagation algorithm are adopted to supervised learn fluctuation of measuring signals and separate the interference magnetic field from the measurement data.LM algorithm is a kind of least square estimation algorithm of nonlinear parameters.It iteratively calculates the jacobian matrix of error performance and the adjustment value of gradient with the regularization method.LM algorithm’s computing efficiency is high and fitting error is very low.The fitting performance and the compensation accuracy of LM-MFNN algorithm are proved to be much better than those of TOLLES-LAWSON(T-L)model with the linear least square(LS)solution by fitting experiments with five different aeromagnetic surveys’data.
基金financially supported by the National Natural Science Foundation of China(No.51532006)the Shanghai Municipal Science and Technology Commission(No.16DZ2260600)the 111 Project of the Ministry of Education and the National Bureau of Foreign Experts(No.D16002).
文摘In reactive-hot-pressed ZrB_(2)-SiC-ZrC ceramics,ZrO_(2) was found to replace ZrC phase,hence leading to confusion in designing ultra-high-temperature ceramics(UHTCs).We employ high-precision X-ray diffraction and electron microscopies to reassess the phase behavior during entire reaction and densification and to reveal the evolution of multiphase relationship at different stages before reaching the final ZrB2-SiC-ZrO_(2) composition.Frozen from transient liquid-phase,bulk glassy phase of 15 vol% was found to be constituted of Zr-Si-B-C-O with stable Zr:O ratio,which starts as early as in the intermediate stage to suppress ZrC in favor of SiC nucleation.Inhomogeneity in phase relations and microstructures results from variation in local transient liquid-phase to develop SiC phase in various modes and rates.As inferred from the earlier report of phase formation,competing reactions for ZrC and ZrB_(2) phases in the initial stage below 1000℃ were mediated via Zr-O-B-C liquid phase.Such liquid phase was moderated by stable B-O components,as initiated from surface oxides of starting powders.This picture under a continuous mother liquid phase can unify the reactions and sintering into a collective meltingenucleationegrowth process,which enables and guides the evolution of multiphase relationship through several stages to reach final densification at relatively low temperature with the help of residual oxides.
基金supported by the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20240969)the National Natural Science Foundation of China(Grants No.51532006 and No.51702168)+3 种基金Shanghai Technical Service Center for Advanced Ceramics Structure Design and Precision Manufacturing(NO.20DZ2294000)the support from Beijing Municipal Natural Science Foundation(Grant No.1212016)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB36000000)the CAS Pioneer Hundred Talents Program.
文摘High dielectric constant can be reached in a reductive-sintered Sr_(1-x)Ba_(x)TiO_(3)barrier-layer capacitor with core‒rim structures as dominant microstructural features.By SEM and aberration-corrected TEM observations,an interfacial zone between the core and rim,named as white-rim(w-rim),was found always enriched with Ba,while the core was free of Ba solution.The reductive liquid-phase sintering resulted in three times the concentrations of oxygen vacancies(VO)into cores and rims compared to their A-site vacancies(VA),while enabling the highest concentration of VO(~17%)without VA in w-rim.The strained core/w-rim interfaces,with obvious interfacial polarizations,which can effectively raise the dielectric constant,were expected to be created from a temporary equilibrium between the cores and the liquidphase.The synergetic evolution of core‒rim structures,SreO vacancies,multiple internal polarized structures can be utilized to better control and optimize dielectric behaviors and other functionalities for perovskite capacitors and other multi-functional ceramics.
基金the National Natural Science Foundation of China (30270800and 40231003).
文摘To study the effects of growing rice （Oryza sativa L.） leaves under the treatment of the short-term elevated CO2 during the period of sink-source transition, several physiological processes such as dynamic changes in photosynthesis, photosynthate accumulation, enzyme activities （sucrose phosphate synthase （SPS）, and sucrose synthase （SS））, and their specific gene （spsl and RSusl） expressions in both mature and developing leaf were measured. Rice seedlings with fully expanded sixth leaf （marked as the source leaf, L6） were kept in elevated （700 μmol/mol） and ambient （350 mol/L） CO2 until the 7th leaf （marked as the sink leaf, L7） fully expanded. The results demonstrated that elevated CO2 significantly increased the rate of leaf elongation and biomass accumulation of L7 during the treatment without affecting the growth of L6. However, in both developing and mature leaves, net photosynthetic assimilation rate （A）, all kinds of photosynthate contents such as starch, sucrose and hexose, activities of SPS and SS and transcript levels of spsl and RSusl were significantly increased under elevated CO2 condition. Results suggested that the elevated CO2 had facilitated photosynthate assimilation, and increased photosynthate supplies from the source leaf to the sink leaf, which accelerated the growth and sink-source transition in new developing sink leaves. The mechanisms of SPS regulation by the elevated CO2 was also discussed.
基金financially supported by the National key R&D Program of China(2016YFB0901600)the Key Research Program of Chinese Academy of Sciences(QYZDJ-SSWJSC013)Chen IW was supported by U.S.Department of Energy BES grant DE-FG02-11ER46814used the facilities(Laboratory for Research on the Structure of Matter)supported by NSF grant DMR-1120901。
文摘For energy storage system,it is still a huge challenge to achieve high energy density and high power density simultaneously.One potential solution is to fabricate electrochemical capacitors(ECs),which store electric energy through surface ion adsorption or redox reactions.Here we report a new electrode material,heavy nitrogen-doped(9.29 at.%)black titania(TiO2-x:N).This unique hybrid material,consisting of conductive amorphous shells supported on nanocrystalline cores,has rapid N-mediated redox reaction(TiO2-xNy+zH++ze■-TiO2-xNyHz),especially in acidic solutions,providing a specific capacitance of 750 Fg-1at 2 m V s-1(707 Fg-1at 1 A g-1),great rate capability(503 F g-1at 20 Ag-1),and maintain stable after initial fading.Being a new developed supercapacitor material,nitrogen-doped black titania may revive the oxide-based supercapacitors.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51532006 and 51472060)Science and Technology Commission of Shanghai Municipality(16DZ2260601)the 111 Project(D16002)of the National Foreign Experts Bureau of China.
文摘Phase relation and microstructure evolution in the pressure-less sintered TiB_(2)‒TiC ceramics preceded with mechanical alloying were systematically studied by a combination of SEM analysis.WC debris from milling balls promotes sintering by dissolving into the TiC phase to achieve dense microstructures at 1600℃.Variation of W solution in TiC grains exposes two types of core-rim structures,with no or more W in dark and white cores respectively but with common medium W in both rims.Diminishing whitecores reveal an exchange reaction between WC and TiC via mechanical alloying to form the Ti_(1-z)W_(z)C phase prior to sintering.The dark-cores inherit from the as-milled TiC power to further enable the reprecipitation of rims from a mixed liquid-phase,which facilitated also the anisotropic growth of TiB_(2) grains.The dark-cores grow persistently in the second-step at 2000℃ enabled by this liquid-phase,which coarsens the TiB2 grains too.With more alloyed phase,sintering was insufficient at 1500℃ with only the surface fluidity from the primary powders,and the second-step sintering increased the fluidity in the liquid-phase to fully densify the binary microstructure.Re-distribution of the alloyed W by two-step sintering rationalizes the evolution process of the binary microstructures and leads to better understanding of the mechanical behaviors.
基金supported by the National Natural Science Foundation under Grants No.51532006the Shanghai Municipal Science and Technology Commission under grant No.16DZ2260600the 111 Project of the Ministry of Education and the National Bureau of Foreign Experts under grand No.D16002.
文摘Core-rim structures were identified as a common feature in hot-pressed ZrB2-SiC-MC ceramics(M=Nb,Hf,Ta and W)by a combination of X-ray diffraction,scanning and transmission electron microscopies.Quantitative analyses associate them with the bi-solubility of M in ZrB2 phase,in which transition of solubility across the core/rim boundary is abrupted,signifying their creation via dissolution-reprecipitation process facilitated by transient liquid-phase.The cores were retained from starting powder after surface melting and the rims were grown from the liquid-phase to incorporate more solutes,leaving the residual liquid to turn into ZrC phase with higher solubility of M.We propose g-point scheme in the ZrB2-MB2 diagrams to combine the bi-solubility and the core-rim structures into an intra-phase relationship created by sintering,leading further to a hierarchical phase relationship.The temperature dependence of flexural strength in the ZrB2-SiC-MC ceramics varies with MC additions,which can be respectively strengthened by the strain energy created in the core-rim structures and metal segregation to grain boundaries.
基金financially supported by the National Natural Science Foundation of China under Grant Nos. 51532006 and 11704238Shanghai Municipal Science and Technology Commission of Shanghai Municipality under Grant No. 16DZ2260601State Administration of Foreign Experts Affairs of China 111 Project under Grant No. D16002
文摘To achieve a better material for thermoelectric power generation device, filled skutterudite Yb0.3 Co_4 Sb_(12) samples were fabricated by melting-quenching-annealing-spark plasma sintering(SPS)method. Two sets of samples, before and after SPS, were investigated. In both the two sets of samples,the average grain size of the samples increases monotonously with the increase of annealing time,while Yb filling fraction firstly increases and then decreases. Yb not filling into the skutterudite remains at the grain boundaries in the form of Yb_2 O_3 after SPS, which could be quantified by the spatially difference method of energy dispersive spectra. Step distribution of Yb filling fraction was observed in the samples annealed for 1 h, which was caused by the microstructural evolution from the peritectic phases to the skutterudite phase. The sample annealed for 3 days and SPS sintered possesses the maximum value of Yb filling fraction 0.249 and the maximum ZT value of 1.24 at 850 K. These results are helpful to better understand the microstructural evolution and Yb filling behavior in skutterudite materials.
基金This work was financially supported by the National Natural Science Foundation of China under Grant Nos. 51532006 and 51325203, Shanghai Municipal Science and Technology Commission of Shanghai Municipality under Grant No. 16DZ2260600, and the 111 Project (D16002). We are grateful to the Shanghai Institute of Ceramics for technical assistance in TEM and SEM experiments, as well as to Prof. R. Huang of East China Normal University for TEM specimen preparations
文摘To achieve a better material for uncooled infrared (IR) detector, polycrystalline VO2(B) thin films with layered W-doping were fabricated on Si substrates by magnetron sputtering, and the best temperature coefficient of resistance (TCR) value reached -4.1%/K. The film synthesis was in a two-step route, first deposition at room temperature and then post-deposition annealing at 450 ℃, to better control the crystallization behavior. Various transmission electron microscopy (TEM) methods were employed to investigate three sets of multi-layered films with different deposition time, 10, 20, and 30 min, with especial emphasis on the effect of layered W-doping scheme on the formation of multiple VO2(B) layers. Spatial-resolved energy dispersive X-ray spectroscopy (EDS) revealed the alternative patterns of W-rich layers and W-poor layers, while the thinner films exhibited better crystallinity and texturing. By comparison with an as-deposited film, it was found that the inter-diffusion between the two types of layers was completed in the deposition step while both remained in amorphous structure. A stable W solution of about 8 cat% in VO2(B) layers measured from all these films indicated that the layered doping can tailor the multi-layered microstructure to optimize the performance of VO2(B) films.
基金supported by the National Natural Science Foundation(Grant Nos.51532006 and 52032002)Shanghai Technical Service Center for Advanced Ceramics Structure Design and Precision Manufacturing(Grant No.20DZ2294000)supported provisionally by the Max-Planck Gesellschaft via the Max-Plack Partner Group in Shanghai Institute of Ceramics,Chinese Academy of Sciences through the years of 2003e2008.
文摘Similar to Si_(3)N_(4)ceramics,β→a phase transformation in SiC ceramics plays a key role in tailoring the microstructures thus optimizing related properties.SiC microstructures are dominated with the core erim structures by AlN-solution,and by EBSD analysis,a-lamellae were revealed as stacking-faults(SF)and twin-boundaries(TB)in b-grains,co-existing with the coreerim structures asα/β→α’/β’transformation by sintering.The structural transformation can proceed much further by gas-pressuresintering than hot-pressing with only RE2O3 agents,while the latter retain a high-density of SF/TB in the metastable b-SiC grains.By high-angle secondary-electron imaging,nanoscale transition-layer(TL)was observed as an inter-phase to fully separate the core and rim,which is created by a transitory equilibrium in the solutionereprecipitation process.The enrichment of AlN or RE in TL demonstrates their segregation to core surface until reaching the super-saturation and before the growth of rims.With higher AlN or RE solution and after sintering,a shear stress can develop from TL contour to drive the expansion of SF/TB in Martensitic transition,especially under an external isotropic pressure.The combinations ofβ→a transformation,coreerim structures and viscous liquid-phase enable the comprehensive assessment of sintering-microstructure-property-performance relationship of SiC ceramics,as demonstrated for their creep behaviors and fracture toughness.
文摘Background： The pathogenicity of cleft lip （CL） is pretty complicated since it is influenced by the interaction of environment and genetic factors. The purpose of this study was to conduct a genome-wide screening of aberrant methylation loci in partial lesion tissues of patients with nonsyndromic CL （NSCL） and preliminarily validate candidate dysmethylated genes associated with NSCL.Methods： Fifteen healthy and sixteen NSCL fetal lip tissue samples were collected. The Infinium HumanMethylation450 BeadChip was used to screen aberrant methylation loci in three NSCL and three healthy lip tissues. The differential methylation sites and functions of the annotated genes between NSCL and healthy lip tissues were analyzed using minfi package of R software, cluster analysis, Gene Ontology （GO） annotation, and metabolic pathway annotation. Gene expression was assessed in nine differentially methylated genes by real-time polymerase chain reaction （PCR）. The transcriptions mRNA levels of three out of nine candidate genes were downregulated remarkably in NSCL lip tissues, and these three genes＇ abnormal methylation loci were validated by pyrosequencing in 16 NSCL cases and 15 healthy cases.Results： In total, 4879 sites in the genes of NSCL odinopoeia fetuses showed aberrant methylation when compared with normal lip tissue genome. Among these, 3661 sites were hypermethylated and 1218 sites were hypomethylated as compared to methylation levels in healthy specimens. These aberrant methylation sites involved 2849 genes and were widely distributed among the chromosomes. Most differentially methylated sites were located in cytosine-phosphoric acid-guanine islands. Based on GO analysis, aberrantly methylated genes were involved in 11 cellular components, 13 molecular functions, and a variety of biological processes. Notably, the transcription of DAB1, REELIN, and FYN was significantly downregulated in lesion tissues of NSCL fetus （P 〈 0.05）. Pyrosequencing results validated that there were two loci in DABI with high methylation status in patient tissues （P 〈 0.05）. Conclusions： We detected numerous aberrantly methylated loci in lesion tissues of NSCL fetus. Aberrant gene expression in the REELIN signaling pathway might be related with NSCL. Decreased transcription of DAB1, a member of REELIN signal pathway, resulted from its abnormal high methylation, which might be one of the factors underlying the occurrence of NSCL.
基金The work was supported by funding from National Key Research and Development Program of China(Grant No.2016YFB0100105)Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2017342)+1 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ16E020003,LY18E020018,LY18E030011,LD18E020004)Natural Science Foundation of Ningbo(Grant No.2018A610012,2018A610010).
文摘A novel solid polymer electrolyte with comb-like structure is prepared via a solvent-free UV-cured method.The relationship between conductivity and molecular weight is investigated and revealed.The optimal electrolyte presents a considerably high conductivity of 1.44·10^(-4)S·cm^(-1)at 30℃.Meanwhile,it shows excellent compatibility with metallic lithium and wide electrochemical window(>5 V).To investigate the safety and cycling performance,the coin cell and soft package battery are assembled respectively.The LiFePO_(4)/Li coin cells exhibit initial discharge specific capacities of 163.2,147.7,137.3 and 108.7 mA·h·g^(-1)at 0.1,0.2,0.5 and 1C under 60℃,respectively.Notably,when the coin cells work at 30℃,the initial discharge specific capacities at 0.05,0.1,0.2 and 0.5C are 140.5,133.5,107.7 and 55.6 mA·h·g^(-1).Significantly,a 3.5 cm×7 cm solid-state soft pack battery is fabricated and cycling at 30℃.The first discharge capacity reaches to 137.5 mA·h·g^(-1)and the capacity retention is as high as 84.4%after 100 cycles at 0.2C and remain 95.5%after 100 cycles at 0.5C,respectively.These results shows a promising solid polymer electrolyte for solid-state batteries with good cycling and safety performance.
基金supported by the National Natural Science Foundation of China[Grant numbers 51532006,51432004]State Administration of Foreign Experts Affairs of China,111 project[Grant number D16002]the Opening Project of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(Grant number KLIFMD201804).
文摘Correlated phase and microstructural evolution are systematically investigated by electron microscopies in Sr-deficient Sr(Ti,Nb)O_(3)(STNO)thermoelectric ceramics incorporated with different fraction of reduced graphene oxide(RGO).It is found that while no impurity except for very few Ti_(3)O_(5) precipitates are observed in monolithic STNO,the Nb-enriched rutile TiO_(2) appears in RGO/STNO composites.With increasing RGO content,the amount of precipitates increase at first and then decrease when RGO content becomes high,which can be ascribed to the formation of local Magneli phase.In addition,the energy-dispersive X-ray spectra combined with cathodoluminescence characterization indicates that the variation of Sr deficiency experiences the opposite trend with respect to the precipitates content.These findings clearly reveal the unique reducing effect of RGO on the microstructure of doped SrTiO_(3) with Sr deficiency,which can greatly facilitate the design of perovskite based thermoelectric materials of hierarchical structure.
基金supported by the National Natural Science Foundation(Grant No.51532006)the National Bureau of Foreign Experts(111 Project No.D16002)。
文摘The A2B2O7 series of ternary oxides are derivatives of fluorite structure over a wide range of rA/rB.Competing by two rare-earths the A-site,La2-xLuxZr2O7 ceramics were found transparent only in pore-free microstructures with similar grain sizes of pyrochlore(PY)and defective fluorite(DF)phases.Mutual solubilities of Lu and La in both phases were found by imaging and energy-dispersive spectroscopy analysis in scanning electron microscope.The dual-phase microstructures were developed with liquid-phase resulted from the exothermal reactions,creating a miscibility gap between two structures to moderate their competing grain growth.Change in grain growth behaviors in liquid-phase is described by a nucleation line in La2Zr2O7-Lu2Zr2O7 phase diagram.Variations of solution levels in DF grains and co-existing of dual-phase grain clusters in common orientation were revealed in transparent ceramics by electron backscattered diffraction,resulted by epitaxial relation of two phases promoted by the liquid-phase.Oxygen vacancies and various hole states common in both phases were revealed by characteristic cathodoluminescence peaks.The collective effects of pores,phase and grain boundaries,oxygen vacancies on scattering or absorption of visible light enables to establish a hierarchical microstructure-transparency relationship in such complex oxide ceramics,which could be tailored or further optimized by controllable sintering.
基金supported by the Natural Science Foundation of Jiangsu Province (BK20210386)the Fundamental Research Funds for the Central Universities (CGPY2024001)+6 种基金the National Natural Science Foundation of China (32102233,32270210,32102172)the Innovation Fund of DICP (DICPI202412)the China Postdoctoral Science Foundation (2024T170421)Jiangsu Funding Program for Excellent Postdoctoral Talent (2023ZB236)the Postdoctoral Fellowship Program of CPSF (GZC20231129)the Key Research and Development Program of Guangdong Province (2022B0202080004)China Agriculture Research System (CARS-004-PS14)。
文摘Phytophthora pathogens secrete numerous apoplastic effectors to manipulate host immunity.Herein,we identified a polysaccharide lyase 1 protein,PsPL1,which acts as an essential virulence factor of P.sojae infection in soybean.However,the overexpression of PsPL1 in P.sojae reduced infection and triggered enhanced immune responses in soybean.PsPL1 exhibited pectin lyase activity and degraded plant pectin to generate pectin oligosaccharides(POSs)with a polymerization degree of 3–14,exhibiting different levels of acetylation and methylation modifications.PsPL1 and the degraded pectin products triggered immune responses in soybean and different Solanaceous plants.The PsPL1-triggered immune responses required RSPL1,a membrane-localized leucine-rich repeat receptor-like protein,which is essential for Phytophthora resistance.Conversely,the PsPL1-degraded product-triggered immune responses depended on the membrane-localized lysin motif receptor-like kinase CERK1.This study reveals that the pectin lyase exhibits a dual immunogenic role during P.sojae infection,which activates plant resistance through different immune receptors and provides novel insights into the function of pectin lyase in host-pathogen interactions.
