The criteria of process parameters(μ≤4),atomic size difference(ε≤5.8,δ≤11 andα≤2),thermodynamic(-14.5≤△Hmix≤6.5 andΩ≥1.8)in the prediction of the phase stability for laser-clad high-entropy alloy coatings...The criteria of process parameters(μ≤4),atomic size difference(ε≤5.8,δ≤11 andα≤2),thermodynamic(-14.5≤△Hmix≤6.5 andΩ≥1.8)in the prediction of the phase stability for laser-clad high-entropy alloy coatings are studied in detail.Besides,the criteria of valence electron concentration(VEC)applied to distinguish the stability of different solid solution phases are as follows:VEC<7.65 for simple BCC,VEC≥7.65 for simple face-centered cubic(FCC),7.14<VEC<7.78 for dual-phase BCC and FCC.Among them,μandεproposed firstly separate the phase stability of laserclad high-entropy alloy coatings quite precisely.The other modified criteria(δ,α,△Hmix,Ω,VEC)are proved to be different from those of the high-entropy alloys synthesized by the traditional casting and smelting processes.展开更多
Titanium diboride(TiB_(2))is an effective grain refiner of Al alloys in the industry that facilitates casting processes by forming uniformly refined microstructures.Although our understanding of the underlying refinem...Titanium diboride(TiB_(2))is an effective grain refiner of Al alloys in the industry that facilitates casting processes by forming uniformly refined microstructures.Although our understanding of the underlying refinement mechanisms has advanced,the atomic kinetics of heterogeneous nucleation of Al on TiB2 remains unknown.Here,we report atomic-scale observations of the heterogeneous nucleation and growth kinetics of Al on self-formed TiB_(2) particles by in situ heating of undercooled Al-5Ti-1B films.We demonstrate that an ordered Al monolayer forms on the Ti-terminated{0001}TiB_(2) surface;then,the surrounding Al atoms are initiated to form an island-shaped Al nucleus with face-centered cubic{111}stacking without the assistance of a Ti-rich buffer layer.The interfacial lattice mismatch between{111}Al and{0001}TiB_(2) causes remarkable out-of-plane strain that decreases gradually with Al nucleus layers increasing to 6 atomic layers.The elastic strain energy originating from this interfacial strain increases the free energy of the Al/TiB2 heterostructure,hence impeding the rapid growth of the Al nucleus.We found that TiB2 particles stabilize the Al nuclei rather than activating their free growth into grains when the experimental undercoolingΔT is lower than the onset undercoolingΔT fg in Greer's free growth model.Our findings provide an atomic-scale physical image of the heterogeneous nucleation and growth mechanisms of Al with inoculator participation and elucidate the strain-dependent growth kinetics of Al nuclei.展开更多
Polye-caprolactone）-b-poly（ethylene glycol）-b-poly（e-caprolactone）（PCL-b-PEG-b-PCL,PCEC） triblock copolymers have been widely investigated in last several decades.Here,by altering the weight ratio of monomers i...Polye-caprolactone）-b-poly（ethylene glycol）-b-poly（e-caprolactone）（PCL-b-PEG-b-PCL,PCEC） triblock copolymers have been widely investigated in last several decades.Here,by altering the weight ratio of monomers in ring-opening polymerization,a series of PCEC triblock copolymers with varying hydrophobicity were synthesized,which were characterized by FTIR,1 H NMR,GPC and DSC.When PCEC copolymers with different weight ratios of PCL/PEG were dispersed in different aqueous solutions,they could self-assemble and form two distinctive nanoparticular structures：micelles or polymersomes.We then chose paclitaxel（PTX） as the model drug and encapsulate PTX into PCEC polymeric micelles and polymersomes.The physicochemical characterizations of the nanoparticles such as morphology,the size and distribution,zeta potential,drug loading content,and encapsulation efficiency were also performed.Our results showed that polymeric micelles or polymersomes from PCEC both displayed narrow size distributions and could achieve high drug loading efficiencies.In vitro cellular uptake results suggested that Nile Red loaded polymeric micelles or polymersomes displayed more internalization after 24 h incubation than those after 4 h incubation.These findings suggest that polymeric micelles and polymersomes based on PCL-b-PEG-b-PCL copolymers have great potential to effectively delivery hydrophobic drugs.展开更多
Synthetic microbial community has widely concerned in the fields of agriculture,food and environment over the past few years.However,there is little consensus on the method to synthetic microbial community from constr...Synthetic microbial community has widely concerned in the fields of agriculture,food and environment over the past few years.However,there is little consensus on the method to synthetic microbial community from construction to functional verification.Here,we review the concept,characteristics,history and applications of synthetic microbial community,summarizing several methods for synthetic microbial community construction,such as isolation culture,core microbiome mining,automated design,and gene editing.In addition,we also systematically summarized the design concepts,technological thresholds,and applicable scenarios of various construction methods,and highlighted their advantages and limitations.Ultimately,this review provides four efficient,detailed,easy-to-understand and-follow steps for synthetic microbial community construction,with major implications for agricultural practices,food production,and environmental governance.展开更多
基金the National Natural Science Foundation of China (No. 51627802)。
文摘The criteria of process parameters(μ≤4),atomic size difference(ε≤5.8,δ≤11 andα≤2),thermodynamic(-14.5≤△Hmix≤6.5 andΩ≥1.8)in the prediction of the phase stability for laser-clad high-entropy alloy coatings are studied in detail.Besides,the criteria of valence electron concentration(VEC)applied to distinguish the stability of different solid solution phases are as follows:VEC<7.65 for simple BCC,VEC≥7.65 for simple face-centered cubic(FCC),7.14<VEC<7.78 for dual-phase BCC and FCC.Among them,μandεproposed firstly separate the phase stability of laserclad high-entropy alloy coatings quite precisely.The other modified criteria(δ,α,△Hmix,Ω,VEC)are proved to be different from those of the high-entropy alloys synthesized by the traditional casting and smelting processes.
基金financially supported by the National Natural Science Foundation of China(Nos.52173224,51821001,52130105,and 52273230)the Natural Science Foundation of Shanghai(No.21ZR1431200)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘Titanium diboride(TiB_(2))is an effective grain refiner of Al alloys in the industry that facilitates casting processes by forming uniformly refined microstructures.Although our understanding of the underlying refinement mechanisms has advanced,the atomic kinetics of heterogeneous nucleation of Al on TiB2 remains unknown.Here,we report atomic-scale observations of the heterogeneous nucleation and growth kinetics of Al on self-formed TiB_(2) particles by in situ heating of undercooled Al-5Ti-1B films.We demonstrate that an ordered Al monolayer forms on the Ti-terminated{0001}TiB_(2) surface;then,the surrounding Al atoms are initiated to form an island-shaped Al nucleus with face-centered cubic{111}stacking without the assistance of a Ti-rich buffer layer.The interfacial lattice mismatch between{111}Al and{0001}TiB_(2) causes remarkable out-of-plane strain that decreases gradually with Al nucleus layers increasing to 6 atomic layers.The elastic strain energy originating from this interfacial strain increases the free energy of the Al/TiB2 heterostructure,hence impeding the rapid growth of the Al nucleus.We found that TiB2 particles stabilize the Al nuclei rather than activating their free growth into grains when the experimental undercoolingΔT is lower than the onset undercoolingΔT fg in Greer's free growth model.Our findings provide an atomic-scale physical image of the heterogeneous nucleation and growth mechanisms of Al with inoculator participation and elucidate the strain-dependent growth kinetics of Al nuclei.
基金supported by National Natural Science Foundation of China(Nos.81571793,81671806 and 51373199)CAMS Innovation Fund for Medical Sciences,Tianjin Municipal Natural Science Foundation(No.15JCZDJC38300)Science and Technology Support Program of Tianjin(No.15RCGFSY00146)
文摘Polye-caprolactone）-b-poly（ethylene glycol）-b-poly（e-caprolactone）（PCL-b-PEG-b-PCL,PCEC） triblock copolymers have been widely investigated in last several decades.Here,by altering the weight ratio of monomers in ring-opening polymerization,a series of PCEC triblock copolymers with varying hydrophobicity were synthesized,which were characterized by FTIR,1 H NMR,GPC and DSC.When PCEC copolymers with different weight ratios of PCL/PEG were dispersed in different aqueous solutions,they could self-assemble and form two distinctive nanoparticular structures：micelles or polymersomes.We then chose paclitaxel（PTX） as the model drug and encapsulate PTX into PCEC polymeric micelles and polymersomes.The physicochemical characterizations of the nanoparticles such as morphology,the size and distribution,zeta potential,drug loading content,and encapsulation efficiency were also performed.Our results showed that polymeric micelles or polymersomes from PCEC both displayed narrow size distributions and could achieve high drug loading efficiencies.In vitro cellular uptake results suggested that Nile Red loaded polymeric micelles or polymersomes displayed more internalization after 24 h incubation than those after 4 h incubation.These findings suggest that polymeric micelles and polymersomes based on PCL-b-PEG-b-PCL copolymers have great potential to effectively delivery hydrophobic drugs.
基金supported by the Natural Science Foundation of China(32360029,32260003)Gui Da Tegang He Zi(2022)57,“Hundred”Talent Projects of Guizhou Province(Qian Ke He[2020]6005).
文摘Synthetic microbial community has widely concerned in the fields of agriculture,food and environment over the past few years.However,there is little consensus on the method to synthetic microbial community from construction to functional verification.Here,we review the concept,characteristics,history and applications of synthetic microbial community,summarizing several methods for synthetic microbial community construction,such as isolation culture,core microbiome mining,automated design,and gene editing.In addition,we also systematically summarized the design concepts,technological thresholds,and applicable scenarios of various construction methods,and highlighted their advantages and limitations.Ultimately,this review provides four efficient,detailed,easy-to-understand and-follow steps for synthetic microbial community construction,with major implications for agricultural practices,food production,and environmental governance.
