In traditional physical metallurgy,once recrystallization occurs,it will proceed to 100%along with time even at relatively low temperatures,resulting in the limited thermal stability of partially recrystallized alloys...In traditional physical metallurgy,once recrystallization occurs,it will proceed to 100%along with time even at relatively low temperatures,resulting in the limited thermal stability of partially recrystallized alloys.Here,we proposed the strategy of achieving the endless recrystallization state at high temperature(~0.6T_(m))in high entropy alloys for the first time.The partially recrystallized microstructures remained stable after annealing at 700℃ for 1440 h toward endless recrystallization with kinetics analysis.Benefiting from the ultra-thermostable heterostructures,the alloy exhibited excellent mechanical properties of~1.6 GPa tensile strength at room temperature and~1.1 GPa tensile strength at 600°C even after exposure at 700℃ for 720 h.The kinetics of recovery,recrystallization,grain growth,and precipitate coarsening were quantitatively analyzed to uncover the mechanisms of endless recrystallization.The results revealed that the stable state of 50%recrystallization at 700℃ can be attributed to the precipitates inhibited recrystallization and the continued recovery decreased stored energy in the non-recrystallized regions.Furthermore,the grain size was stable in the recrystallized regions due to the strong pinning effect of the intergranular precipitates with slow coarsening rates.These findings created a brand-new state of endless recrystallization with the combination of recovery and recrystallization,which can significantly broaden the service temperature range of heterogeneous materials.展开更多
Donghua steel continuous casting-rolling(DSCCR)production line is an endless rolling production line independently integrated and developed by a Chinese enterprise.To solve the problem of out-of-control shape caused b...Donghua steel continuous casting-rolling(DSCCR)production line is an endless rolling production line independently integrated and developed by a Chinese enterprise.To solve the problem of out-of-control shape caused by insufficient adjustment ability of work roll bending force of DSCCR finishing mills,the backup roll contours of the finishing mill were optimized considering multi-objectives,and varying contact length backup roll(VCR)contours matching the concave work rolls were designed based on the rapid rolls-strip deformation calculation model,which integrated the elastic deformation of the rolls and the fast plastic deformation of the rolled strip.The simulation results showed that VCR configuration can significantly enhance the control efficiency of the work roll bending force and increase the transverse stiffness of rolling mill compared with the conventional roll configuration.In addition,VCR backup roll can improve the contact state between backup roll and work roll.The industrial production showed that the bending force setup value was more reasonable and the strip crown control accuracy was improved.展开更多
Chinese visitors begin to find the hidden beauty of Namibia’s vast tourist attractions THE feature film The Trail,better known as LA PISTE,focuses on the relationship between a British geologist and his daughter agai...Chinese visitors begin to find the hidden beauty of Namibia’s vast tourist attractions THE feature film The Trail,better known as LA PISTE,focuses on the relationship between a British geologist and his daughter against the backdrop of one of the most remote and exotic locations in Namibia.The most impressive part of the film is the country’s spectacular展开更多
This research explores the potential of an immersive and interactive online archive to enhance our understanding of historic architecture through the study of models.It reports on implementing an augmented reality mob...This research explores the potential of an immersive and interactive online archive to enhance our understanding of historic architecture through the study of models.It reports on implementing an augmented reality mobile application that exhibits a model for the unbuilt Endless House,1959,by Frederick Kiesler.A reflective critique,from the researcher’s point of view,and initial feedback from a small sample of architecture students,provides an insight into users’experience of the exhibition,its value as a research tool,and as an educational resource.Building on existing technologies and established research methods,we present an alternative way of exhibiting a large-scaled model for public engagement and research collaboration between academics,archivists,and conservators.Results discuss the development of the mobile application with interactive features specifically designed for an architectural audience.It touches on issues associated with documenting,interpreting,and exhibiting architectural models,emphasizing accessibility,accuracy,engagement,combining 3D and 2D digital assets,and user experience.It was found that the interactive and immersive features of the exhibition enhanced the researchers’scope to spatially inspect the model,visually experience it,collaborate with others,and strengthen connections between the model and other examples of Kiesler’s textual and visual archival materials.展开更多
The 2008 Second International Magic Festival—the Olympics for magicians—will be held at Beijing Happy Valley from September 29-October 5. About 30 world-renowned magicians from nine countries and regions, including ...The 2008 Second International Magic Festival—the Olympics for magicians—will be held at Beijing Happy Valley from September 29-October 5. About 30 world-renowned magicians from nine countries and regions, including Switzerland, Greece, Japan and China,展开更多
The first word I learnt in my life is "mum". From then on, I learnt to know more about this magic word from my mum’s tender love.When I was a child, my curiosity about everything made Mum worry a lot about ...The first word I learnt in my life is "mum". From then on, I learnt to know more about this magic word from my mum’s tender love.When I was a child, my curiosity about everything made Mum worry a lot about me. Naturally, I was interested in everything that Mum didn’t want me to do. She didn’t criticize me or punish me, instead she spent her valuable time with me to make sure I was free from any trouble.展开更多
The existence of significant core-surface temperature differences in the strips during the rolling process in the endless strip production line leads to low accuracy in calculating the hot rolling force model assuming...The existence of significant core-surface temperature differences in the strips during the rolling process in the endless strip production line leads to low accuracy in calculating the hot rolling force model assuming uniform temperature.This paper divides the deformation zone of strips into cells along the thick and the roll direction considering the non-uniform distribution of temperature,strain,strain rate in the thick direction cell of the strips,and the change of deformation resistance in the roll direction cell of strips.Then this study separately establishes the temperature matrix,strain matrix,and strain rate matrix on the"thick direction-roll direction"of strips,and constructs a deformation resistance calculation model based on the matrix cell.Further,a model for calculating rolling forces applicable to this production line was derived based on the Orowan equilibrium differential equation.The accuracy of the rolling force model and temperature variation patterns of the thick-directional units of the rolled parts during rolling were verified by hot rolling simulation experiments on a strip with an embedded block of the same material.Take an endless strip production line in China as an example to carry out simulation calculations of Q235 material.The results show that the average calculation error of the model built in this paper is 4.4%.Simulation and error analysis of multiple materials and multiple specifications of strip steel show that the prediction accuracy of the model in this paper meets the requirements of the production line,which provides theoretical support for the formulation and optimization of the rolling process of this production line.展开更多
悦读·明其义.An endless journey:The eternal quest for science.无尽的征程:科学的永恒探索.Science represents humanity's most organized attempt to comprehend the mysteries of our universe,which is built upon the ...悦读·明其义.An endless journey:The eternal quest for science.无尽的征程:科学的永恒探索.Science represents humanity's most organized attempt to comprehend the mysteries of our universe,which is built upon the work of countless gifted individuals.Many renowned researchers began their careers as laboratory assistants before becoming outstanding experts in charge of major scientific initiatives that shape our modern world.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51771149 and 51871183)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Grant No.CX202022)。
文摘In traditional physical metallurgy,once recrystallization occurs,it will proceed to 100%along with time even at relatively low temperatures,resulting in the limited thermal stability of partially recrystallized alloys.Here,we proposed the strategy of achieving the endless recrystallization state at high temperature(~0.6T_(m))in high entropy alloys for the first time.The partially recrystallized microstructures remained stable after annealing at 700℃ for 1440 h toward endless recrystallization with kinetics analysis.Benefiting from the ultra-thermostable heterostructures,the alloy exhibited excellent mechanical properties of~1.6 GPa tensile strength at room temperature and~1.1 GPa tensile strength at 600°C even after exposure at 700℃ for 720 h.The kinetics of recovery,recrystallization,grain growth,and precipitate coarsening were quantitatively analyzed to uncover the mechanisms of endless recrystallization.The results revealed that the stable state of 50%recrystallization at 700℃ can be attributed to the precipitates inhibited recrystallization and the continued recovery decreased stored energy in the non-recrystallized regions.Furthermore,the grain size was stable in the recrystallized regions due to the strong pinning effect of the intergranular precipitates with slow coarsening rates.These findings created a brand-new state of endless recrystallization with the combination of recovery and recrystallization,which can significantly broaden the service temperature range of heterogeneous materials.
基金This work was financially supported by the National Natural Science Foundation of China(51774139)the Natural Science Foundation of Hebei Province(E2020209014).
文摘Donghua steel continuous casting-rolling(DSCCR)production line is an endless rolling production line independently integrated and developed by a Chinese enterprise.To solve the problem of out-of-control shape caused by insufficient adjustment ability of work roll bending force of DSCCR finishing mills,the backup roll contours of the finishing mill were optimized considering multi-objectives,and varying contact length backup roll(VCR)contours matching the concave work rolls were designed based on the rapid rolls-strip deformation calculation model,which integrated the elastic deformation of the rolls and the fast plastic deformation of the rolled strip.The simulation results showed that VCR configuration can significantly enhance the control efficiency of the work roll bending force and increase the transverse stiffness of rolling mill compared with the conventional roll configuration.In addition,VCR backup roll can improve the contact state between backup roll and work roll.The industrial production showed that the bending force setup value was more reasonable and the strip crown control accuracy was improved.
文摘Chinese visitors begin to find the hidden beauty of Namibia’s vast tourist attractions THE feature film The Trail,better known as LA PISTE,focuses on the relationship between a British geologist and his daughter against the backdrop of one of the most remote and exotic locations in Namibia.The most impressive part of the film is the country’s spectacular
文摘This research explores the potential of an immersive and interactive online archive to enhance our understanding of historic architecture through the study of models.It reports on implementing an augmented reality mobile application that exhibits a model for the unbuilt Endless House,1959,by Frederick Kiesler.A reflective critique,from the researcher’s point of view,and initial feedback from a small sample of architecture students,provides an insight into users’experience of the exhibition,its value as a research tool,and as an educational resource.Building on existing technologies and established research methods,we present an alternative way of exhibiting a large-scaled model for public engagement and research collaboration between academics,archivists,and conservators.Results discuss the development of the mobile application with interactive features specifically designed for an architectural audience.It touches on issues associated with documenting,interpreting,and exhibiting architectural models,emphasizing accessibility,accuracy,engagement,combining 3D and 2D digital assets,and user experience.It was found that the interactive and immersive features of the exhibition enhanced the researchers’scope to spatially inspect the model,visually experience it,collaborate with others,and strengthen connections between the model and other examples of Kiesler’s textual and visual archival materials.
文摘The 2008 Second International Magic Festival—the Olympics for magicians—will be held at Beijing Happy Valley from September 29-October 5. About 30 world-renowned magicians from nine countries and regions, including Switzerland, Greece, Japan and China,
文摘The first word I learnt in my life is "mum". From then on, I learnt to know more about this magic word from my mum’s tender love.When I was a child, my curiosity about everything made Mum worry a lot about me. Naturally, I was interested in everything that Mum didn’t want me to do. She didn’t criticize me or punish me, instead she spent her valuable time with me to make sure I was free from any trouble.
基金Supported by Special Funds of the Central Government for Guiding Local Scientific and Technological Development(Grant No.YDZX20191400002149)。
文摘The existence of significant core-surface temperature differences in the strips during the rolling process in the endless strip production line leads to low accuracy in calculating the hot rolling force model assuming uniform temperature.This paper divides the deformation zone of strips into cells along the thick and the roll direction considering the non-uniform distribution of temperature,strain,strain rate in the thick direction cell of the strips,and the change of deformation resistance in the roll direction cell of strips.Then this study separately establishes the temperature matrix,strain matrix,and strain rate matrix on the"thick direction-roll direction"of strips,and constructs a deformation resistance calculation model based on the matrix cell.Further,a model for calculating rolling forces applicable to this production line was derived based on the Orowan equilibrium differential equation.The accuracy of the rolling force model and temperature variation patterns of the thick-directional units of the rolled parts during rolling were verified by hot rolling simulation experiments on a strip with an embedded block of the same material.Take an endless strip production line in China as an example to carry out simulation calculations of Q235 material.The results show that the average calculation error of the model built in this paper is 4.4%.Simulation and error analysis of multiple materials and multiple specifications of strip steel show that the prediction accuracy of the model in this paper meets the requirements of the production line,which provides theoretical support for the formulation and optimization of the rolling process of this production line.
文摘悦读·明其义.An endless journey:The eternal quest for science.无尽的征程:科学的永恒探索.Science represents humanity's most organized attempt to comprehend the mysteries of our universe,which is built upon the work of countless gifted individuals.Many renowned researchers began their careers as laboratory assistants before becoming outstanding experts in charge of major scientific initiatives that shape our modern world.
