Three-dimensional geochemical modeling of ore-forming elements is crucial for predicting deep mineralization.This approach provides key information for the quantitative prediction of deep mineral localization,three-di...Three-dimensional geochemical modeling of ore-forming elements is crucial for predicting deep mineralization.This approach provides key information for the quantitative prediction of deep mineral localization,three-dimensional fine interpolation,analysis of spatial distribution patterns,and extraction of quantitative mineral-seeking markers.The Yechangping molybdenum(Mo)deposit is a significant and extensive porphyry-skarn deposit in the East Qinling-Dabie Mo polymetallic metallogenic belt at the southern margin of the North China Block.Abundant borehole data on oreforming elements underpin deep geochemical predictions.The methodology includes the following steps:(1)Threedimensional geological modeling of the deposit was established.(2)Correlation,cluster,and factor analyses post delineation of mineralization stages and determination of mineral generation sequence to identify(Cu,Pb,Zn,Ag)and(Mo,W,mfe)assemblages.(3)A three-dimensional geochemical block model was constructed for Mo,W,mfe,Cu,Zn,Pb,and Ag using the ordinary kriging method,and the variational function was developed.(4)Spatial distribution and enrichment characteristics analysis of ore-forming elements are performed to extract geological information,employing the variogram and w(Cu+Pb+Zn+Ag)/w(Mo+W)as predictive indicators.(5)Identifying the western,northwestern,and southwestern areas of the mine with limited mineralization potential,contrasted by the northeastern and southeastern areas favorable for mineral exploration.展开更多
Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale pr...Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.展开更多
The fine-tuned expression dynamics of the effector genes are pivotal for the transition from vegetative growth to host colonization of pathogenic filamentous fungi.However,mechanisms underlying the dynamic regulation ...The fine-tuned expression dynamics of the effector genes are pivotal for the transition from vegetative growth to host colonization of pathogenic filamentous fungi.However,mechanisms underlying the dynamic regulation of these genes remain largely unknown.Here,through comparative transcriptome and chromatin immunoprecipitation sequencing(ChIP-seq)analyses of the methyltransferase PoKmt6 in rice blast fungus Pyricularia oryzae(syn.Magnaporthe oryzae),we found that PoKmt6-mediated H3K27me3 deposition was enriched mainly at fast-evolving regions and contributed to the silencing of a subset of secreted proteins(SP)and transposable element(TE)families during the vegetative growth of P.oryzae.Intriguingly,we observed that a group of SP genes,which were depleted of H3K27me3 modification,could also be silenced via the H3K27me3-mediated repression of the nearby TEs.In conclusion,our results indicate that H3K27me3 modification mediated by PoKmt6 regulates the expression of some SP genes in fast-evolving regions through the suppression of nearby TEs.展开更多
The paper presents our contribution to the full 3D finite element modelling of a hybrid stepping motor using COMSOL Multiphysics software. This type of four-phase motor has a permanent magnet interposed between the tw...The paper presents our contribution to the full 3D finite element modelling of a hybrid stepping motor using COMSOL Multiphysics software. This type of four-phase motor has a permanent magnet interposed between the two identical and coaxial half stators. The calculation of the field with or without current in the windings (respectively with or without permanent magnet) is done using a mixed formulation with strong coupling. In addition, the local high saturation of the ferromagnetic material and the radial and axial components of the magnetic flux are taken into account. The results obtained make it possible to clearly observe, as a function of the intensity of the bus current or the remanent induction, the saturation zones, the lines, the orientations and the magnetic flux densities. 3D finite element modelling provide more accurate numerical data on the magnetic field through multiphysics analysis. This analysis considers the actual operating conditions and leads to the design of an optimized machine structure, with or without current in the windings and/or permanent magnet.展开更多
This study aims to investigate the benefcial efects of surface retaining elements (SREs) on the mechanical behaviors of bolted rock and roadway stability. 3D printing (3DP) technology is utilized to create rock analog...This study aims to investigate the benefcial efects of surface retaining elements (SREs) on the mechanical behaviors of bolted rock and roadway stability. 3D printing (3DP) technology is utilized to create rock analogue prismatic specimens for conducting this investigation. Uniaxial compression tests with acoustic emission (AE) and digital image correlation techniques have been conducted on 3DP specimens bolted with diferent SREs. The results demonstrate that the strength and modulus of elasticity of the bolted specimens show a positive correlation with the area of the SRE;the AE characteristics of the bolted specimens are higher than those of the unbolted specimen, but they decrease with an increase in SRE area, thus further improving the integrity of the bolted specimens. The reinforcement efect of SREs on the surrounding rock of roadways is further analyzed using numerical modelling and feld test. The results provide a better understanding of the role of SREs in rock bolting and the optimization of rock bolting design. Furthermore, they verify the feasibility of 3DP for rock analogues in rock mechanics tests.展开更多
Petrography and geochemistry of the altered and unaltered host rocks surrounding the Koktokay No.3 pegmatite revealed that the unaltered amphibolite is mainly composed of hornblende, plagioclase, and ilmenite.Beyond t...Petrography and geochemistry of the altered and unaltered host rocks surrounding the Koktokay No.3 pegmatite revealed that the unaltered amphibolite is mainly composed of hornblende, plagioclase, and ilmenite.Beyond these primary components, the altered host rocks contain a few newly formed minerals, including biotite,tourmaline, chlorine, and muscovite. The alteration zone surrounding the Koktokay No.3 pegmatite is limited to 2.0 m, characterized by biotitization, tourmalization, and chloritization. In the altered host rocks, the contents of SiO2, MgO, MnO, Na2O, and TiO2 did not vary greatly.However, Al2O3 showed a weak decreasing trend with the increasing distance from the pegmatite contact zone, while Fe2O3 and CaO showed an increasing trend. The contents of Li, Rb, and Cs in the altered host rocks were much higher than those in the unaltered host rocks, decreasing with distance from the contact. The chondrite-normalized rare earth element（REE） pattern of the altered and unaltered host rock was right-inclined from La to Lu, but enriched in light REEs over heavy REEs after hydrothermal alteration. An isocon plot shows that some oxides migrated in with an order of P2O5〉K2O 〉TiO2〉Al2O3〉SiO2〉MnO≥MgO, while others migrated out with an order of Na2O 〉CaO 〉Fe2O3. For REEs, the migration ratios are positive values withCs 〉Rb 〉Li 〉Nb 〉Ta 〉Be, signifying that all REEs migrated from the exsolved magmatic fluid into the altered host rocks. It was concluded that diffusion was the only mechanism for migration of ore-forming elements in the alteration zone. The effective diffusion coefficients（Deff）of LiF, RbF, and CsF were estimated under a fluid temperature of 500–550℃. Using a function of concentration（C（x,t）） and distance（x）, the order of migration distance was determined to be LiF 〉CsF 〉RbF, with diffusion times of （3.39 ± 0.35）× 10^6,（3.19 ± 0.28） × 10^5 and（6.33 ± 0.05） × 10^5 years, respectively.展开更多
The microstructures of Ti-14Al-21Nb and Ti-14Al-20Nb-2Mo-3.2V(wt%) alloys have been investikated by transmission electron microscopy(TEM).The phase constitution and the orientation relationship between α2and βwere i...The microstructures of Ti-14Al-21Nb and Ti-14Al-20Nb-2Mo-3.2V(wt%) alloys have been investikated by transmission electron microscopy(TEM).The phase constitution and the orientation relationship between α2and βwere identified by means of the selected area diffraction and the micro-diffraction techniques.Results show that,compared to Ti-14Al-21Nb,the alloying elements Mo and V can greatly increase the fraction of β phase and improve significantly the microstructures of Ti-14Al-20Nb-2Mo-3.2V.The ordered B2 structure is also evident in the residual βgrains of the latter alloy.展开更多
This paper reviews recent research on ductility improvement of B-undoped Ni_3Al alloys.Ni_3Al binary alloys with hypostoichiometric compositions show appreciable ductility at room temperature when the samples are prep...This paper reviews recent research on ductility improvement of B-undoped Ni_3Al alloys.Ni_3Al binary alloys with hypostoichiometric compositions show appreciable ductility at room temperature when the samples are prepared by recrystallization annealing after cold pressing,although the alloys with stoichiometric and hyperstoichiometric compositions remain brittle.Melt-spun ribbons with hypostoichiometric compositions contain fine anti-phase domains (APDs),while no APD can be seen in melt-spun ribbons with a hyperstoichiometric composition.The ductility in hypostoichiometric Ni_3Al alloys is associated with low ordering energy of the alloys.The addition of ternary elements,which have been classified as γ formers such as Pd,Pt,Cu,Co and Ag.improves ductility of Ni_3Al alloys.Correspondingly,the microstructure of the melt-spun ribbons consists of fine APDs.The addition of γ' formers such as Si,Ti,Zr,V,Nb and Ta leads to brittle intergranular frac- ture.No APD was observed in the melt-spun ribbons of these ternary alloys.展开更多
Segmented all-electron basis set of triple zeta valence quality plus polarization functions(TZP)for the elements of the fifth row to be used together with the zero-order regular approximation(ZORA)is carefully constru...Segmented all-electron basis set of triple zeta valence quality plus polarization functions(TZP)for the elements of the fifth row to be used together with the zero-order regular approximation(ZORA)is carefully constructed.To correctly describe electrons distant from atomic nuclei,the basis set is augmented with diffuse functions giving rise to a set designated as ATZP-ZORA.At the ZORA-B3LYP theoretical level,these sets are used to calculate the ionization energy and mean dipole polarizability of some atoms,bond length,dissociation energy,and harmonic vibrational frequency of diatomic molecules.Then,these results are compared with the theoretical and experimental data found in the literature.Even considering that our sets are relatively compact,they are sufficiently accurate and reliable to perform property calculations involving simultaneously electrons from the inner shell and outer shell.The performances of the ZORA and second-order Douglas-Kroll-Hess Hamiltonians are evaluated and the results are also discussed.展开更多
It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of gr...It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of grains has its own domain and dislocation structure. There are mono- and polydomains with and without dislocations. The grains of the main phase of monoand polydomains without dislocations and polydomains with dislocations were formed by diffusion in the solid phase. In these conditions NiAl3 phase is located on the grain boundary of the main phase. The Ni2Al3 phase is located at the triple joints of the main phase.展开更多
The Ni_3B phase was formed when boron (0.5 at. pct B) was added to the intermetallic of sto- ichiometric and off-stoichiometric (Ni-24 at. pct Al) compounds. In the alloy of stoichiometric composition the particles o...The Ni_3B phase was formed when boron (0.5 at. pct B) was added to the intermetallic of sto- ichiometric and off-stoichiometric (Ni-24 at. pct Al) compounds. In the alloy of stoichiometric composition the particles of Ni_3B phase has the size around 0.1μm and is located on the grain boundary of the main phase. The decreasing of concentrations of Al in the ofF-stoichiometric alloy leads to increase in the degree of the long-range order parameter, increasing the concen- trations of boron in the solid solution and decreasing its localization on the grain boundary. Microalloying of boron leads to increasing in the fraction of grain monodomains with disloca- tions up to 0.7 in the alloy of the off-stoichiometric composition and up to 1 in the alloy of the stoichiometric composition. It was established the correlation between the degree of the concentration inhomogeneity, average density of the dislocations and the average long range-order parameter.展开更多
This research presents damage causes of the pylons in the ancient Egyptian temples based on 3D finite elements analysis. The main purpose of the research determines the failure causes of the first pylon of the Ramessi...This research presents damage causes of the pylons in the ancient Egyptian temples based on 3D finite elements analysis. The main purpose of the research determines the failure causes of the first pylon of the Ramessium temple, which is situated in Upper Egypt, at Luxor “Thebes” on the west bank of the Nile River. The first pylon of Ramessium temple subjected to seismic activity effects on long term, combined with several structural damage factors such as the defects resulting from the construction technique, where the builder used the poor quality of stones in foundations of the pylon, the building materials residue was used as filler for the core of the pylon walls, and it lacked vertical joints between the courses. In addition to it founded on alluvial soil that is vulnerable to contaminated water, it is still suffering damage factors and urban trespasses at the moment. All of the former factors helped the pylon to be affected by the earthquakes loads that occurred on it. The structural behavior of the pylon under self-weight and earthquakes loads were carried out by Numerical analysis to find out the loads and stresses which caused collapsing of the pylon. Results of the study indicated that the pylon subjected to a horizontal displacement due to old earthquakes force, led to collapse of the pylon. Finally, the study represents use of modern technique to study the structural behavior of the most important architectural units in ancient Egyptian temples to identify the causes of its collapse.展开更多
AE中Element 3D是一款具有real time rendering(实时渲染)特性的插件,即在制作3D效果过程中可以直接在屏幕上看到渲染效果,CG运算的效率得以大幅提升,是AE中为数不多的支持完全3D渲染特性的插件之一。本文结合两个具有代表性的实例分析...AE中Element 3D是一款具有real time rendering(实时渲染)特性的插件,即在制作3D效果过程中可以直接在屏幕上看到渲染效果,CG运算的效率得以大幅提升,是AE中为数不多的支持完全3D渲染特性的插件之一。本文结合两个具有代表性的实例分析了该插件实现三维特效制作的方法。展开更多
Esophageal disease is a common disorder of the digestive system that can severely affect the quality of life andprognosis of patients. Esophageal stenting is an effective treatment that has been widely used in clinica...Esophageal disease is a common disorder of the digestive system that can severely affect the quality of life andprognosis of patients. Esophageal stenting is an effective treatment that has been widely used in clinical practice.However, esophageal stents of different types and parameters have varying adaptability and effectiveness forpatients, and they need to be individually selected according to the patient’s specific situation. The purposeof this study was to provide a reference for clinical doctors to choose suitable esophageal stents. We used 3Dprinting technology to fabricate esophageal stents with different ratios of thermoplastic polyurethane (TPU)/(Poly-ε-caprolactone) PCL polymer, and established an artificial neural network model that could predict the radial forceof esophageal stents based on the content of TPU, PCL and print parameter. We selected three optimal ratios formechanical performance tests and evaluated the biomechanical effects of different ratios of stents on esophagealimplantation, swallowing, and stent migration processes through finite element numerical simulation and in vitrosimulation tests. The results showed that different ratios of polymer stents had different mechanical properties,affecting the effectiveness of stent expansion treatment and the possibility of postoperative complications of stentimplantation.展开更多
基金supported by the Key Research Project of China Geological Survey(Grant No.DD20230564)the Research Project of Natural Resources Department of Gansu Province(Grant No.202219)。
文摘Three-dimensional geochemical modeling of ore-forming elements is crucial for predicting deep mineralization.This approach provides key information for the quantitative prediction of deep mineral localization,three-dimensional fine interpolation,analysis of spatial distribution patterns,and extraction of quantitative mineral-seeking markers.The Yechangping molybdenum(Mo)deposit is a significant and extensive porphyry-skarn deposit in the East Qinling-Dabie Mo polymetallic metallogenic belt at the southern margin of the North China Block.Abundant borehole data on oreforming elements underpin deep geochemical predictions.The methodology includes the following steps:(1)Threedimensional geological modeling of the deposit was established.(2)Correlation,cluster,and factor analyses post delineation of mineralization stages and determination of mineral generation sequence to identify(Cu,Pb,Zn,Ag)and(Mo,W,mfe)assemblages.(3)A three-dimensional geochemical block model was constructed for Mo,W,mfe,Cu,Zn,Pb,and Ag using the ordinary kriging method,and the variational function was developed.(4)Spatial distribution and enrichment characteristics analysis of ore-forming elements are performed to extract geological information,employing the variogram and w(Cu+Pb+Zn+Ag)/w(Mo+W)as predictive indicators.(5)Identifying the western,northwestern,and southwestern areas of the mine with limited mineralization potential,contrasted by the northeastern and southeastern areas favorable for mineral exploration.
基金Supported by Science Center for Gas Turbine Project of China (Grant No.P2022-B-IV-014-001)Frontier Leading Technology Basic Research Special Project of Jiangsu Province of China (Grant No.BK20212007)the BIT Research and Innovation Promoting Project of China (Grant No.2022YCXZ019)。
文摘Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC composites.An entirely new process is introduced to weave the preform with three-dimensional orthogonal architecture.The 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary conditions.Three RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the microscale.Besides,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix models.The prediction results at the mesoscale correspond closely to the experimental values.The effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into consideration.The multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.
基金the grants from the National Natural Science Foundation of China(U1805232,31770156,and 32172365)the China Postdoctoral Science Foundation(2021M690637)。
文摘The fine-tuned expression dynamics of the effector genes are pivotal for the transition from vegetative growth to host colonization of pathogenic filamentous fungi.However,mechanisms underlying the dynamic regulation of these genes remain largely unknown.Here,through comparative transcriptome and chromatin immunoprecipitation sequencing(ChIP-seq)analyses of the methyltransferase PoKmt6 in rice blast fungus Pyricularia oryzae(syn.Magnaporthe oryzae),we found that PoKmt6-mediated H3K27me3 deposition was enriched mainly at fast-evolving regions and contributed to the silencing of a subset of secreted proteins(SP)and transposable element(TE)families during the vegetative growth of P.oryzae.Intriguingly,we observed that a group of SP genes,which were depleted of H3K27me3 modification,could also be silenced via the H3K27me3-mediated repression of the nearby TEs.In conclusion,our results indicate that H3K27me3 modification mediated by PoKmt6 regulates the expression of some SP genes in fast-evolving regions through the suppression of nearby TEs.
文摘The paper presents our contribution to the full 3D finite element modelling of a hybrid stepping motor using COMSOL Multiphysics software. This type of four-phase motor has a permanent magnet interposed between the two identical and coaxial half stators. The calculation of the field with or without current in the windings (respectively with or without permanent magnet) is done using a mixed formulation with strong coupling. In addition, the local high saturation of the ferromagnetic material and the radial and axial components of the magnetic flux are taken into account. The results obtained make it possible to clearly observe, as a function of the intensity of the bus current or the remanent induction, the saturation zones, the lines, the orientations and the magnetic flux densities. 3D finite element modelling provide more accurate numerical data on the magnetic field through multiphysics analysis. This analysis considers the actual operating conditions and leads to the design of an optimized machine structure, with or without current in the windings and/or permanent magnet.
基金supported by the Young Scientist Project of National Key Research and Development Program of China(2021YFC2900600)the National Natural Science Foundation of China(52074166)Shandong Province(ZR2021YQ38).
文摘This study aims to investigate the benefcial efects of surface retaining elements (SREs) on the mechanical behaviors of bolted rock and roadway stability. 3D printing (3DP) technology is utilized to create rock analogue prismatic specimens for conducting this investigation. Uniaxial compression tests with acoustic emission (AE) and digital image correlation techniques have been conducted on 3DP specimens bolted with diferent SREs. The results demonstrate that the strength and modulus of elasticity of the bolted specimens show a positive correlation with the area of the SRE;the AE characteristics of the bolted specimens are higher than those of the unbolted specimen, but they decrease with an increase in SRE area, thus further improving the integrity of the bolted specimens. The reinforcement efect of SREs on the surrounding rock of roadways is further analyzed using numerical modelling and feld test. The results provide a better understanding of the role of SREs in rock bolting and the optimization of rock bolting design. Furthermore, they verify the feasibility of 3DP for rock analogues in rock mechanics tests.
基金supported jointly by the Natural Science Foundation of China (Grant No.41372104)Research Project of Xinjiang Nonferrous Metals Industry (Group) Co.,Ltd.(Grant No.YSKY2011-02)
文摘Petrography and geochemistry of the altered and unaltered host rocks surrounding the Koktokay No.3 pegmatite revealed that the unaltered amphibolite is mainly composed of hornblende, plagioclase, and ilmenite.Beyond these primary components, the altered host rocks contain a few newly formed minerals, including biotite,tourmaline, chlorine, and muscovite. The alteration zone surrounding the Koktokay No.3 pegmatite is limited to 2.0 m, characterized by biotitization, tourmalization, and chloritization. In the altered host rocks, the contents of SiO2, MgO, MnO, Na2O, and TiO2 did not vary greatly.However, Al2O3 showed a weak decreasing trend with the increasing distance from the pegmatite contact zone, while Fe2O3 and CaO showed an increasing trend. The contents of Li, Rb, and Cs in the altered host rocks were much higher than those in the unaltered host rocks, decreasing with distance from the contact. The chondrite-normalized rare earth element（REE） pattern of the altered and unaltered host rock was right-inclined from La to Lu, but enriched in light REEs over heavy REEs after hydrothermal alteration. An isocon plot shows that some oxides migrated in with an order of P2O5〉K2O 〉TiO2〉Al2O3〉SiO2〉MnO≥MgO, while others migrated out with an order of Na2O 〉CaO 〉Fe2O3. For REEs, the migration ratios are positive values withCs 〉Rb 〉Li 〉Nb 〉Ta 〉Be, signifying that all REEs migrated from the exsolved magmatic fluid into the altered host rocks. It was concluded that diffusion was the only mechanism for migration of ore-forming elements in the alteration zone. The effective diffusion coefficients（Deff）of LiF, RbF, and CsF were estimated under a fluid temperature of 500–550℃. Using a function of concentration（C（x,t）） and distance（x）, the order of migration distance was determined to be LiF 〉CsF 〉RbF, with diffusion times of （3.39 ± 0.35）× 10^6,（3.19 ± 0.28） × 10^5 and（6.33 ± 0.05） × 10^5 years, respectively.
文摘The microstructures of Ti-14Al-21Nb and Ti-14Al-20Nb-2Mo-3.2V(wt%) alloys have been investikated by transmission electron microscopy(TEM).The phase constitution and the orientation relationship between α2and βwere identified by means of the selected area diffraction and the micro-diffraction techniques.Results show that,compared to Ti-14Al-21Nb,the alloying elements Mo and V can greatly increase the fraction of β phase and improve significantly the microstructures of Ti-14Al-20Nb-2Mo-3.2V.The ordered B2 structure is also evident in the residual βgrains of the latter alloy.
文摘This paper reviews recent research on ductility improvement of B-undoped Ni_3Al alloys.Ni_3Al binary alloys with hypostoichiometric compositions show appreciable ductility at room temperature when the samples are prepared by recrystallization annealing after cold pressing,although the alloys with stoichiometric and hyperstoichiometric compositions remain brittle.Melt-spun ribbons with hypostoichiometric compositions contain fine anti-phase domains (APDs),while no APD can be seen in melt-spun ribbons with a hyperstoichiometric composition.The ductility in hypostoichiometric Ni_3Al alloys is associated with low ordering energy of the alloys.The addition of ternary elements,which have been classified as γ formers such as Pd,Pt,Cu,Co and Ag.improves ductility of Ni_3Al alloys.Correspondingly,the microstructure of the melt-spun ribbons consists of fine APDs.The addition of γ' formers such as Si,Ti,Zr,V,Nb and Ta leads to brittle intergranular frac- ture.No APD was observed in the melt-spun ribbons of these ternary alloys.
基金the Conselho Nacional de Desenvolvimento Científico Tecnológico(Brazilian Agency)。
文摘Segmented all-electron basis set of triple zeta valence quality plus polarization functions(TZP)for the elements of the fifth row to be used together with the zero-order regular approximation(ZORA)is carefully constructed.To correctly describe electrons distant from atomic nuclei,the basis set is augmented with diffuse functions giving rise to a set designated as ATZP-ZORA.At the ZORA-B3LYP theoretical level,these sets are used to calculate the ionization energy and mean dipole polarizability of some atoms,bond length,dissociation energy,and harmonic vibrational frequency of diatomic molecules.Then,these results are compared with the theoretical and experimental data found in the literature.Even considering that our sets are relatively compact,they are sufficiently accurate and reliable to perform property calculations involving simultaneously electrons from the inner shell and outer shell.The performances of the ZORA and second-order Douglas-Kroll-Hess Hamiltonians are evaluated and the results are also discussed.
文摘It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of grains has its own domain and dislocation structure. There are mono- and polydomains with and without dislocations. The grains of the main phase of monoand polydomains without dislocations and polydomains with dislocations were formed by diffusion in the solid phase. In these conditions NiAl3 phase is located on the grain boundary of the main phase. The Ni2Al3 phase is located at the triple joints of the main phase.
文摘The Ni_3B phase was formed when boron (0.5 at. pct B) was added to the intermetallic of sto- ichiometric and off-stoichiometric (Ni-24 at. pct Al) compounds. In the alloy of stoichiometric composition the particles of Ni_3B phase has the size around 0.1μm and is located on the grain boundary of the main phase. The decreasing of concentrations of Al in the ofF-stoichiometric alloy leads to increase in the degree of the long-range order parameter, increasing the concen- trations of boron in the solid solution and decreasing its localization on the grain boundary. Microalloying of boron leads to increasing in the fraction of grain monodomains with disloca- tions up to 0.7 in the alloy of the off-stoichiometric composition and up to 1 in the alloy of the stoichiometric composition. It was established the correlation between the degree of the concentration inhomogeneity, average density of the dislocations and the average long range-order parameter.
文摘This research presents damage causes of the pylons in the ancient Egyptian temples based on 3D finite elements analysis. The main purpose of the research determines the failure causes of the first pylon of the Ramessium temple, which is situated in Upper Egypt, at Luxor “Thebes” on the west bank of the Nile River. The first pylon of Ramessium temple subjected to seismic activity effects on long term, combined with several structural damage factors such as the defects resulting from the construction technique, where the builder used the poor quality of stones in foundations of the pylon, the building materials residue was used as filler for the core of the pylon walls, and it lacked vertical joints between the courses. In addition to it founded on alluvial soil that is vulnerable to contaminated water, it is still suffering damage factors and urban trespasses at the moment. All of the former factors helped the pylon to be affected by the earthquakes loads that occurred on it. The structural behavior of the pylon under self-weight and earthquakes loads were carried out by Numerical analysis to find out the loads and stresses which caused collapsing of the pylon. Results of the study indicated that the pylon subjected to a horizontal displacement due to old earthquakes force, led to collapse of the pylon. Finally, the study represents use of modern technique to study the structural behavior of the most important architectural units in ancient Egyptian temples to identify the causes of its collapse.
基金Nanning Technology and Innovation Special Program(20204122)and Research Grant for 100 Talents of Guangxi Plan.
文摘Esophageal disease is a common disorder of the digestive system that can severely affect the quality of life andprognosis of patients. Esophageal stenting is an effective treatment that has been widely used in clinical practice.However, esophageal stents of different types and parameters have varying adaptability and effectiveness forpatients, and they need to be individually selected according to the patient’s specific situation. The purposeof this study was to provide a reference for clinical doctors to choose suitable esophageal stents. We used 3Dprinting technology to fabricate esophageal stents with different ratios of thermoplastic polyurethane (TPU)/(Poly-ε-caprolactone) PCL polymer, and established an artificial neural network model that could predict the radial forceof esophageal stents based on the content of TPU, PCL and print parameter. We selected three optimal ratios formechanical performance tests and evaluated the biomechanical effects of different ratios of stents on esophagealimplantation, swallowing, and stent migration processes through finite element numerical simulation and in vitrosimulation tests. The results showed that different ratios of polymer stents had different mechanical properties,affecting the effectiveness of stent expansion treatment and the possibility of postoperative complications of stentimplantation.
