Mechano luminescence(ML),which involves the emission of light under mechanical stimuli,shows great potential in various applications such as sensing,imaging,and energy harvesting.Current research suggests that the lum...Mechano luminescence(ML),which involves the emission of light under mechanical stimuli,shows great potential in various applications such as sensing,imaging,and energy harvesting.Current research suggests that the luminescence mechanism of ML is typically connected to specific defects present within the material.In this study,we focus on the investigation of ML defects in Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions,employing a combination of experimental and theoretical approaches.Through experimental analysis,we confirmed the presence of the heterojunction and its influence on ML intensity,and the optimal doping ratio for the heterojunction in ML was established.Furthermore,we examined the influence of varying Pr^(3+)doping concentrations on ML behavior and a proof-of-concept was demonstrated using the X-rays charged heterostructural phosphor as a stress sensor for biological applications.The position and concentration of internal defects in the ML material were scrutinized through thermo luminescence tests employing the variable heating rate method and positron annihilation.Complementing the experimental findings,theoretical simulations were conducted to elucidate the underlying mechanisms responsible for the observed ML defects.Density functional theory calculations were employed to investigate the energy levels,charge transfer processes,and lattice distortions within the heterojunctions under mechanical stress.Theoretical predictions were compared and validated against the experimental results.The integration of experimental and theoretical approaches provides a comprehensive understanding of the ML behavior of Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions.The insights gained from this research contribute to the development of novel ML materials and pave the way for their applications in next-generation sensing and energy conversion devices.展开更多
Strengthening in Inconel 718 superalloy is derived from dislocation interaction withγ"precipitates,which exist in disk-shaped three possible orientation variants with their{100}habit plane normal to each other.T...Strengthening in Inconel 718 superalloy is derived from dislocation interaction withγ"precipitates,which exist in disk-shaped three possible orientation variants with their{100}habit plane normal to each other.The interactions between dislocations andγ"precipitates vary according to theγ"orienta-tion variants,which makes the deformation behaviour complicated and difficult to reveal experimentally.In this work,γ"variant distributions of Inconel 718 samples were tailored by ageing heat treatment under either tensile or compressive stress.Theγ"variant-sensitive deformation behaviours were then studied by in situ tensile tests via neutron diffraction at room temperature.It is demonstrated that yield-ing first takes place in grains oriented with<110>parallel to the loading direction.An identical lattice strain response to applied stress of both theγmatrix and theγ"precipitates was observed during yield-ing,suggesting that dislocations shearing through theγ"precipitates is predominant at this stage.Vari-ations in yield strength for samples with differentγ"variant distributions were observed,which can be attributed to different strengthening that arises from interactions between dislocation and differentγ"variants.展开更多
The effects of vanadium addition on the microstructural evolution and mechanical properties of AlCrFe_(2)Ni_(2) high-entropy alloy(HEA)were investigated.The results showed that the AlCrFe_(2)Ni_(2)V_(0.2) HEA was comp...The effects of vanadium addition on the microstructural evolution and mechanical properties of AlCrFe_(2)Ni_(2) high-entropy alloy(HEA)were investigated.The results showed that the AlCrFe_(2)Ni_(2)V_(0.2) HEA was composed of FCC phase,disordered BCC phase,and ordered BCC(B2)phase.With the increase in vanadium content,the formation of FCC phase was inhibited,and a transition from FCC phase to BCC phase occurred.The FCC phase disappeared completely when the value of x exceeds 0.4 in AlCrFe_(2)Ni_(2)V_(x) HEAs.Besides,the amplitude-modulated microstructure morphology transformed from a B2 phase matrix with dispersed BCC nano-phase into an alternating interconnected B2 and BCC phases.Vanadium element has the function of stabilizing BCC phase and B2 phase in AlCrFe_(2)Ni_(2)V_(x) alloys.The hardness of AlCrFe_(2)Ni_(2)V_(x) alloys increased from HV 332.4 to HV 590.7,while the yield strength increased from 765 to 1744.6 MPa with increasing vanadium content,which was mainly due to the decreasing content of FCC phase and the solid solution strengthening of vanadium element.At the same time,the compression ratio of the alloys decreased with the disappearance of the FCC phase.Among the alloys,the AlCrFe_(2)Ni_(2)V_(0.2) alloy possessed the most excellent comprehensive mechanical properties with yield strength,fracture strength,and compressive ratio 1231.1,2861.9 MPa,and 44.5%,respectively.展开更多
The article is the result of theoretical and experimental studies aimed at determining the structural groups of modern bituminous materials in order to assess the raw materials, production technology, rational directi...The article is the result of theoretical and experimental studies aimed at determining the structural groups of modern bituminous materials in order to assess the raw materials, production technology, rational directions for their use in construction, the road industry and waterproofing. Commercial oil bitumen, raw tars and heavy oil residues (semi-finished products) of oil refineries aimed at meeting large-tonnage needs have been studied. The assessment was carried out according to the group hydrocarbon composition, by liquid chromatography using model compounds. Comparative analysis showed a general trend for all studied samples of petroleum bitumen: low content of asphaltenes (from 3.9 to 23.9 wt.%), low content of resins (from 11 to 19.07 wt%), insufficient for the formation of stable structuring layers, and a significant content of aromatic hydrocarbons, including heavy aromatic compounds (more than 20 wt.%). An assumption was made about the influence of the origin and the structure obtained during the processing of asphaltenes and resins on the transition from one type of bituminous structure to another based on the lyophility of high-molecular group components. A comparative structural characteristic of heavy oil residues from gasoline and oil production is considered in comparison with bitumens of various viscosities. Recommendations are given on the technology of processing petroleum feedstock and the use of heavy oils in order to obtain a given bitumen structure for the production of rational bitumen products for construction and waterproofing.展开更多
基金supported by the National Natural Science Foundation of China(52201008,52372003)Natural Science Foundation of Heilongjiang Province of China(ZD2023E004)+1 种基金Fundamental Research Funds for the Central Universities(3072020CF2515,3072022CFJ2504)the State Key Laboratory of Particle Detection and Electronics(SKLPDE-KF-202311)。
文摘Mechano luminescence(ML),which involves the emission of light under mechanical stimuli,shows great potential in various applications such as sensing,imaging,and energy harvesting.Current research suggests that the luminescence mechanism of ML is typically connected to specific defects present within the material.In this study,we focus on the investigation of ML defects in Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions,employing a combination of experimental and theoretical approaches.Through experimental analysis,we confirmed the presence of the heterojunction and its influence on ML intensity,and the optimal doping ratio for the heterojunction in ML was established.Furthermore,we examined the influence of varying Pr^(3+)doping concentrations on ML behavior and a proof-of-concept was demonstrated using the X-rays charged heterostructural phosphor as a stress sensor for biological applications.The position and concentration of internal defects in the ML material were scrutinized through thermo luminescence tests employing the variable heating rate method and positron annihilation.Complementing the experimental findings,theoretical simulations were conducted to elucidate the underlying mechanisms responsible for the observed ML defects.Density functional theory calculations were employed to investigate the energy levels,charge transfer processes,and lattice distortions within the heterojunctions under mechanical stress.Theoretical predictions were compared and validated against the experimental results.The integration of experimental and theoretical approaches provides a comprehensive understanding of the ML behavior of Pr^(3+)-doped NaNbO_(3)/LiNbO_(3)heterojunctions.The insights gained from this research contribute to the development of novel ML materials and pave the way for their applications in next-generation sensing and energy conversion devices.
基金support from the Guangdong Introducing Innovative and Entrepreneurial Teams(No.2016ZT06G025)and the financial support from the Centre for Doctoral Training in Innovative Metal Processing(IMPaCT)funded by the UK Engineering and Physical Sciences Research Council(EPSRC,No.EP/L016206/1).The authors also acknowledge useful discussions by Dr.Xingzhong Liang and the allocation of beam time(RB1820207)at ENGIN-X,ISIS,Rutherford Appleton Labora-tory.Chinnapat Panwisawas would like to acknowledge the funding from Innovation Fellowship by EPSRC,UK Research and Innovation(UKRI,No.EP/S000828/2).Shuyan Zhang gratefully acknowledges the support from the Guangdong Major Project of Basic and Ap-plied Basic Research(No.2020B0301030001)and the Strategic Pri-ority Research Program of the Chinese Academy of Sciences(No.XDC04000000).
文摘Strengthening in Inconel 718 superalloy is derived from dislocation interaction withγ"precipitates,which exist in disk-shaped three possible orientation variants with their{100}habit plane normal to each other.The interactions between dislocations andγ"precipitates vary according to theγ"orienta-tion variants,which makes the deformation behaviour complicated and difficult to reveal experimentally.In this work,γ"variant distributions of Inconel 718 samples were tailored by ageing heat treatment under either tensile or compressive stress.Theγ"variant-sensitive deformation behaviours were then studied by in situ tensile tests via neutron diffraction at room temperature.It is demonstrated that yield-ing first takes place in grains oriented with<110>parallel to the loading direction.An identical lattice strain response to applied stress of both theγmatrix and theγ"precipitates was observed during yield-ing,suggesting that dislocations shearing through theγ"precipitates is predominant at this stage.Vari-ations in yield strength for samples with differentγ"variant distributions were observed,which can be attributed to different strengthening that arises from interactions between dislocation and differentγ"variants.
基金financially supported by the National Natural Science Foundation of China(Nos.51801029,52101048)the Natural Science Foundation of Guangdong Province(No.2022A1515012591)the Innovation and Entrepreneurship Training Program for College Students of Guangdong University of Technology(Nos.xj202111845622,xj202111845644).
文摘The effects of vanadium addition on the microstructural evolution and mechanical properties of AlCrFe_(2)Ni_(2) high-entropy alloy(HEA)were investigated.The results showed that the AlCrFe_(2)Ni_(2)V_(0.2) HEA was composed of FCC phase,disordered BCC phase,and ordered BCC(B2)phase.With the increase in vanadium content,the formation of FCC phase was inhibited,and a transition from FCC phase to BCC phase occurred.The FCC phase disappeared completely when the value of x exceeds 0.4 in AlCrFe_(2)Ni_(2)V_(x) HEAs.Besides,the amplitude-modulated microstructure morphology transformed from a B2 phase matrix with dispersed BCC nano-phase into an alternating interconnected B2 and BCC phases.Vanadium element has the function of stabilizing BCC phase and B2 phase in AlCrFe_(2)Ni_(2)V_(x) alloys.The hardness of AlCrFe_(2)Ni_(2)V_(x) alloys increased from HV 332.4 to HV 590.7,while the yield strength increased from 765 to 1744.6 MPa with increasing vanadium content,which was mainly due to the decreasing content of FCC phase and the solid solution strengthening of vanadium element.At the same time,the compression ratio of the alloys decreased with the disappearance of the FCC phase.Among the alloys,the AlCrFe_(2)Ni_(2)V_(0.2) alloy possessed the most excellent comprehensive mechanical properties with yield strength,fracture strength,and compressive ratio 1231.1,2861.9 MPa,and 44.5%,respectively.
文摘The article is the result of theoretical and experimental studies aimed at determining the structural groups of modern bituminous materials in order to assess the raw materials, production technology, rational directions for their use in construction, the road industry and waterproofing. Commercial oil bitumen, raw tars and heavy oil residues (semi-finished products) of oil refineries aimed at meeting large-tonnage needs have been studied. The assessment was carried out according to the group hydrocarbon composition, by liquid chromatography using model compounds. Comparative analysis showed a general trend for all studied samples of petroleum bitumen: low content of asphaltenes (from 3.9 to 23.9 wt.%), low content of resins (from 11 to 19.07 wt%), insufficient for the formation of stable structuring layers, and a significant content of aromatic hydrocarbons, including heavy aromatic compounds (more than 20 wt.%). An assumption was made about the influence of the origin and the structure obtained during the processing of asphaltenes and resins on the transition from one type of bituminous structure to another based on the lyophility of high-molecular group components. A comparative structural characteristic of heavy oil residues from gasoline and oil production is considered in comparison with bitumens of various viscosities. Recommendations are given on the technology of processing petroleum feedstock and the use of heavy oils in order to obtain a given bitumen structure for the production of rational bitumen products for construction and waterproofing.
