Ab initio molecular dynamics calculations have been carried out to search for the ground state structure of Fe_(n)Ti_(13-n)clusters and measure the thermal expansion of Fe_(n)Ti_(13-n).The volume of Fe_(n)Ti_(13-n)clu...Ab initio molecular dynamics calculations have been carried out to search for the ground state structure of Fe_(n)Ti_(13-n)clusters and measure the thermal expansion of Fe_(n)Ti_(13-n).The volume of Fe_(n)Ti_(13-n)clusters during thermal expansion is jointly determined by anharmonic interaction and magneto-volume effect.It has been found that Fe_(6)Ti_(7),Fe_9Ti_(4),Fe_(11)Ti_(2),and Fe_(13)clusters can exhibit the remarkable magneto-volume effect with abnormal volume behaviors and magnetic moment behaviors during thermal expansion.A prerequisite for the magneto-volume effect of Fe_(n)Ti_(13-n)clusters during thermal expansion has been revealed and the magnitude of the magneto-volume is also approximately determined.Furthermore,the magneto-volume behaviors of Fe_(n)Ti_(13-n)clusters are qualitatively characterized by the energy contour map.Our results shed light on the mechanism of the magneto-volume effect in Fe_(n)Ti_(13-n)clusters during thermal expansion,which can guide the design of nanomaterials with zero expansion or even controllable expansion properties.展开更多
Using first-principles pseudo-potential plane wave method, the energetics, geometrical and electronic structures of three Al13I cluster isomers were calculated. The calculation results of the binding energy indicate A...Using first-principles pseudo-potential plane wave method, the energetics, geometrical and electronic structures of three Al13I cluster isomers were calculated. The calculation results of the binding energy indicate Al13I cluster is more stable than Al13 cluster although its electrons are not a magic number as in Alia cluster, and among Al13I cluster isomers the ＂Bridge＂ structure is the most stable, the second is the ＂Ontop＂ structure, and the worst is the ＂Hollow＂ structure. By analyzing the geometrical structures of Al13I cluster isomers, it is found that after I atom and Al13 cluster combine the geometrical structures of Al13 moieties are changed besides Al13I Hollow cluster, in which the Alia moiety is still a regular icosahedron. For Al13I Ontop cluster, the Al13 moiety has a shrinking trend to I, whereas in Al13I Bridge cluster it is distorted. Mulliken population analysis shows for the interaction of electrons between Al-I atoms in Al13I cluster not only there exists an ionic bonding but there is a covalent bonding. Part of electrons in the Alia cluster transfer to I as Al13 cluster and I atom combine. The order of the strength of covalent bonding between Al13 moiety and I in Al13I cluster isomers is Al13IBridge〉Al13IHollow〉Al13I Ontop. Further analysis of electric structures of Al13 and Al13I clusters indicates a higher stability of Al13I cluster than Al13 cluster can be attributed to the s-p hybridization of 3s and 3p electrons of Al in Al13 moiety induced by 1 doped, which leads to fewer electrons N（EF） at EF in Al13I and a larger energy gap △EH-L between HOMO and LUMO levels in Al13I cluster. The distinguish of structural stability of Al13I cluster isomers mainly originates from their different magnitudes .in decrease of N（EF） and increase of △EH-L relative to Al13 cluster. The fewest N（EF） and the largest △EH-L are responsible for the high stability of Al13I Bridge cluster.展开更多
An organic-inorganic hybrid sealing agent was fabricated and used in the plasma sprayed Al_(2)O_(3)-13 wt%TiO_(2)coating,and conventional silicone agent was also used for comparison.Protection performance of the coati...An organic-inorganic hybrid sealing agent was fabricated and used in the plasma sprayed Al_(2)O_(3)-13 wt%TiO_(2)coating,and conventional silicone agent was also used for comparison.Protection performance of the coatings was comprehensively evaluated based on both anti-corrosion and anti-biofouling properties.The results reveal that the sealing treatment is remarkably useful to decrease the porosity of the coating,and the porosity of the coating sealed with the hybrid agent is only 0.035%.Immersion corrosion test and Tafel polarization test reveal that the sealed coating with the hybrid agent exhibits a better corrosion resistance by compared with the coating sealed with silicone agent.The corrosion current density i_(corr) of the hybrid agent sealed coating is only 0.7×10^(-6)A·cm^(-2).Moreover,anti-biofouling tests both in the outdoor analogue hydraulic environment and in the natural marine environment prove that the mentioned novel coating presents a better combination of corrosion resistance and anti-biofouling property by compared with the other coatings,and it could be used as a protection of metal components in the marine environment.展开更多
Electronic and magnetic properties of 13-atom Rh clusters with three possible high symmetry geometries have been studied by using the first-principles DV-LSD method. An anomalous symmetry dependence of the cluster mag...Electronic and magnetic properties of 13-atom Rh clusters with three possible high symmetry geometries have been studied by using the first-principles DV-LSD method. An anomalous symmetry dependence of the cluster magnetism was found that the total magnetic moment of the icosahedral Rh13 cluster is smaller than that of the other two lower-symmetry clusters in a wide range of interatomic spacings. An energy difference is identified to explain this anomalous relationship, which has been found to be also useful for judging whether the broadening technique is correctly used and whether multiple input potentials must be used to reach the actual ground state in the LSD calculations. The calculated results are compared and discussed with those of previous theory and recent experiment. The actual geometry of the Rh13 cluster is suggested to be a distorted icosahedron.展开更多
In this work,high-manganese aluminium bronze CuMn_(13)Al_(7)samples were prepared by arc additive manufacturing technology.The phase composition,microstructure,and crystal structure of the high-manganese aluminium bro...In this work,high-manganese aluminium bronze CuMn_(13)Al_(7)samples were prepared by arc additive manufacturing technology.The phase composition,microstructure,and crystal structure of the high-manganese aluminium bronze CuMn_(13)Al_(7)arc additive manufactured samples were analysed using direct-reading spectrometer,metallographic microscope,scanning electron microscope,and transmission electron microscope.The micro-hardness tester,tensile tester,impact tester,and electrochemical workstation were also used to test the performance of the CuMn_(13)Al_(7)samples.By studying the microstructure and properties of the CuMn_(13)Al_(7)samples,it was found that preparation of the samples by the arc additive manufacturing technology ensured good forming quality,almost no defects,and good metallurgical bonding inside the sample.The metallographic structure(α+β+point phase)mainly comprises the following:the metallographic structure in the equiaxed grain region has an obvious grain boundaryα;the metallographic structure in the remelting region has no obvious grain boundaryα;the thermal influence on the metallographic structure produced a weaker grain boundaryαthan the equiaxed grain region.The transverse and longitudinal cross sections of the sample had uniform microhardness distributions,and the average microhardness values were 190.5 HV0.1 and 192.7 HV0.1,respectively.The sample also had excellent mechanical properties:yield strength of 301 MPa,tensile strength of 633 MPa,elongation of 43.5%,reduction of area by 58%,Charpy impact value of 68 J/cm^(2)at–20℃,and dynamic potential polarisation curve test results.Further,it was shown that the average corrosion potential of the sample was–284.5 mV,and the average corrosion current density was 4.1×10–3 mA/cm^(2).展开更多
COIN-Gaia 13 is a newly discovered open cluster revealed by Gaia DR2 data.It is a nearby open cluster with a distance of about 513 pc.Combined with the five-dimensional astrometric data of Gaia EDR3 with higher accura...COIN-Gaia 13 is a newly discovered open cluster revealed by Gaia DR2 data.It is a nearby open cluster with a distance of about 513 pc.Combined with the five-dimensional astrometric data of Gaia EDR3 with higher accuracy,we use the membership assignment algorithm(pyUPMASK)to determine the membership of COINGaia 13 in a large extended spatial region.The cluster has 478 identified candidate members.After obtaining reliable cluster members,we further study its basic properties and spatial distribution.Our results show that there is an obvious extended structure of the cluster in the X-Y plane.This elongated structure is distributed along the spiral arm,and the whole length is about 270 pc.The cluster age is 250 Myr,the total mass is about 439 M_(⊙) and the tidal radius of the cluster is about 11 pc.Since more than half of member stars(352 stars)are located outside twice the tidal radius,it is suspected that this cluster is undergoing the dynamic dissolution process.Furthermore,the spatial distribution and kinematic analysis indicate that the extended structure in COIN-Gaia 13 is more likely to be caused by differential rotation of the Galaxy.展开更多
基金the support from the National Natural Science Foundation of China(Grant No.52171038)key R&D projects in Shandong Province(Grant No.2021SFGC1001)+1 种基金supported by the Special Funding in the Project of the Taishan Scholar Construction Engineering and the program of Jinan Science and Technology Bureau(Grant No.2020GXRC019)new material demonstration platform construction project from Ministry of Industry and Information Technology of China(Grant No.2020-370104-34-03-043952-01-11)。
文摘Ab initio molecular dynamics calculations have been carried out to search for the ground state structure of Fe_(n)Ti_(13-n)clusters and measure the thermal expansion of Fe_(n)Ti_(13-n).The volume of Fe_(n)Ti_(13-n)clusters during thermal expansion is jointly determined by anharmonic interaction and magneto-volume effect.It has been found that Fe_(6)Ti_(7),Fe_9Ti_(4),Fe_(11)Ti_(2),and Fe_(13)clusters can exhibit the remarkable magneto-volume effect with abnormal volume behaviors and magnetic moment behaviors during thermal expansion.A prerequisite for the magneto-volume effect of Fe_(n)Ti_(13-n)clusters during thermal expansion has been revealed and the magnitude of the magneto-volume is also approximately determined.Furthermore,the magneto-volume behaviors of Fe_(n)Ti_(13-n)clusters are qualitatively characterized by the energy contour map.Our results shed light on the mechanism of the magneto-volume effect in Fe_(n)Ti_(13-n)clusters during thermal expansion,which can guide the design of nanomaterials with zero expansion or even controllable expansion properties.
基金This work was supported by the Science & Technology Major Programs of Ministry of Education of China (No. 101139)
文摘Using first-principles pseudo-potential plane wave method, the energetics, geometrical and electronic structures of three Al13I cluster isomers were calculated. The calculation results of the binding energy indicate Al13I cluster is more stable than Al13 cluster although its electrons are not a magic number as in Alia cluster, and among Al13I cluster isomers the ＂Bridge＂ structure is the most stable, the second is the ＂Ontop＂ structure, and the worst is the ＂Hollow＂ structure. By analyzing the geometrical structures of Al13I cluster isomers, it is found that after I atom and Al13 cluster combine the geometrical structures of Al13 moieties are changed besides Al13I Hollow cluster, in which the Alia moiety is still a regular icosahedron. For Al13I Ontop cluster, the Al13 moiety has a shrinking trend to I, whereas in Al13I Bridge cluster it is distorted. Mulliken population analysis shows for the interaction of electrons between Al-I atoms in Al13I cluster not only there exists an ionic bonding but there is a covalent bonding. Part of electrons in the Alia cluster transfer to I as Al13 cluster and I atom combine. The order of the strength of covalent bonding between Al13 moiety and I in Al13I cluster isomers is Al13IBridge〉Al13IHollow〉Al13I Ontop. Further analysis of electric structures of Al13 and Al13I clusters indicates a higher stability of Al13I cluster than Al13 cluster can be attributed to the s-p hybridization of 3s and 3p electrons of Al in Al13 moiety induced by 1 doped, which leads to fewer electrons N（EF） at EF in Al13I and a larger energy gap △EH-L between HOMO and LUMO levels in Al13I cluster. The distinguish of structural stability of Al13I cluster isomers mainly originates from their different magnitudes .in decrease of N（EF） and increase of △EH-L relative to Al13 cluster. The fewest N（EF） and the largest △EH-L are responsible for the high stability of Al13I Bridge cluster.
基金the National Natural Science Foundation of China(No.51379070)the Graduate Research and Innovation Projects of Jiangsu Province(No.KYCX21_0463)。
文摘An organic-inorganic hybrid sealing agent was fabricated and used in the plasma sprayed Al_(2)O_(3)-13 wt%TiO_(2)coating,and conventional silicone agent was also used for comparison.Protection performance of the coatings was comprehensively evaluated based on both anti-corrosion and anti-biofouling properties.The results reveal that the sealing treatment is remarkably useful to decrease the porosity of the coating,and the porosity of the coating sealed with the hybrid agent is only 0.035%.Immersion corrosion test and Tafel polarization test reveal that the sealed coating with the hybrid agent exhibits a better corrosion resistance by compared with the coating sealed with silicone agent.The corrosion current density i_(corr) of the hybrid agent sealed coating is only 0.7×10^(-6)A·cm^(-2).Moreover,anti-biofouling tests both in the outdoor analogue hydraulic environment and in the natural marine environment prove that the mentioned novel coating presents a better combination of corrosion resistance and anti-biofouling property by compared with the other coatings,and it could be used as a protection of metal components in the marine environment.
基金Supported by the Youth nature Science Foundation of Educational Bureau of Sichuan Province (212-114879).
文摘Electronic and magnetic properties of 13-atom Rh clusters with three possible high symmetry geometries have been studied by using the first-principles DV-LSD method. An anomalous symmetry dependence of the cluster magnetism was found that the total magnetic moment of the icosahedral Rh13 cluster is smaller than that of the other two lower-symmetry clusters in a wide range of interatomic spacings. An energy difference is identified to explain this anomalous relationship, which has been found to be also useful for judging whether the broadening technique is correctly used and whether multiple input potentials must be used to reach the actual ground state in the LSD calculations. The calculated results are compared and discussed with those of previous theory and recent experiment. The actual geometry of the Rh13 cluster is suggested to be a distorted icosahedron.
基金University Synergy Innovation Program of Anhui Province(Grant No.GXXT-2019-022)Anhui Provincial Natural Science Foundation of China(Grant No.1908085QE174)the Talent Program of Anhui Science and Technology University(Grant No.RCYJ201905).
文摘In this work,high-manganese aluminium bronze CuMn_(13)Al_(7)samples were prepared by arc additive manufacturing technology.The phase composition,microstructure,and crystal structure of the high-manganese aluminium bronze CuMn_(13)Al_(7)arc additive manufactured samples were analysed using direct-reading spectrometer,metallographic microscope,scanning electron microscope,and transmission electron microscope.The micro-hardness tester,tensile tester,impact tester,and electrochemical workstation were also used to test the performance of the CuMn_(13)Al_(7)samples.By studying the microstructure and properties of the CuMn_(13)Al_(7)samples,it was found that preparation of the samples by the arc additive manufacturing technology ensured good forming quality,almost no defects,and good metallurgical bonding inside the sample.The metallographic structure(α+β+point phase)mainly comprises the following:the metallographic structure in the equiaxed grain region has an obvious grain boundaryα;the metallographic structure in the remelting region has no obvious grain boundaryα;the thermal influence on the metallographic structure produced a weaker grain boundaryαthan the equiaxed grain region.The transverse and longitudinal cross sections of the sample had uniform microhardness distributions,and the average microhardness values were 190.5 HV0.1 and 192.7 HV0.1,respectively.The sample also had excellent mechanical properties:yield strength of 301 MPa,tensile strength of 633 MPa,elongation of 43.5%,reduction of area by 58%,Charpy impact value of 68 J/cm^(2)at–20℃,and dynamic potential polarisation curve test results.Further,it was shown that the average corrosion potential of the sample was–284.5 mV,and the average corrosion current density was 4.1×10–3 mA/cm^(2).
基金supported by National Key R&D Program of China(No.2019YFA0405501)the science research grants from the China Manned Space Project(No.CMS-CSST-2021-A08)+4 种基金support from the National Natural Science Foundation of China(NSFC,Grant Nos.12090040 and 12090042)the NSFC(Grant No.12073060)the Youth Innovation Promotion Association CASthe Innovation Team Funds of China West Normal University(Grant No.KCXTD2022-6)the Sichuan Youth Science and Technology Innovation Research Team(21CXTD0038)。
文摘COIN-Gaia 13 is a newly discovered open cluster revealed by Gaia DR2 data.It is a nearby open cluster with a distance of about 513 pc.Combined with the five-dimensional astrometric data of Gaia EDR3 with higher accuracy,we use the membership assignment algorithm(pyUPMASK)to determine the membership of COINGaia 13 in a large extended spatial region.The cluster has 478 identified candidate members.After obtaining reliable cluster members,we further study its basic properties and spatial distribution.Our results show that there is an obvious extended structure of the cluster in the X-Y plane.This elongated structure is distributed along the spiral arm,and the whole length is about 270 pc.The cluster age is 250 Myr,the total mass is about 439 M_(⊙) and the tidal radius of the cluster is about 11 pc.Since more than half of member stars(352 stars)are located outside twice the tidal radius,it is suspected that this cluster is undergoing the dynamic dissolution process.Furthermore,the spatial distribution and kinematic analysis indicate that the extended structure in COIN-Gaia 13 is more likely to be caused by differential rotation of the Galaxy.
