In December 2019,coronavirus disease 2019(COVID-19)caused by a novel coronavirus(SARS-CoV-2)broke out in Wuhan,China,and has spread widely all over the world,reaching the pandemic level.[1]According to the latest WHO ...In December 2019,coronavirus disease 2019(COVID-19)caused by a novel coronavirus(SARS-CoV-2)broke out in Wuhan,China,and has spread widely all over the world,reaching the pandemic level.[1]According to the latest WHO report,693,224 cases of COVID-19 were confirmed globally as of March 30,2020,with more than 33,000 deaths.[2]Because COVID-19 is highly contagious and harmful,it is crucial to determine the predictors of severe infection and death for risk stratification and guiding clinical treatment and intervention.展开更多
Angular rolling technology can overcome the size limitation of plate mill equipment and product heavy steel plate with large unit weight or improve the production efficiency of small width spreading ratio product.With...Angular rolling technology can overcome the size limitation of plate mill equipment and product heavy steel plate with large unit weight or improve the production efficiency of small width spreading ratio product.With the DEFORM software,the numerical simulation study of the angular rolling process was carried out,and the relation laws of the width,rolling force and strain of the rolled piece under different angular rolling process conditions were obtained.The simulation results show that with the rotation angle increasing,the width of the rolled piece increases.Comparing with the conventional rolling process,the rolling force changes gradually during the biting and throwing stage of the angular rolling pass.With the rotation angle increasing,both the equivalent strains in the thickness direction and in the width direction gradually increase.According to the pattern and dimension's changing formula in the double-pass angular rolling process,the prediction model of angle,reduction and width spreading is built.The opening value of side guide is set for the rotation angle controlling.For one 5000 mm heavy plate mill,the automation control system was modified,and the angular rolling technology was applied online.The absolute deviation of target width does not exceed±20 mm and the relative deviation does not exceed 1%.The large unit weight plate that cannot be rolled with traditional process,can be produced now,and the annual output increases by 10000 t.展开更多
文摘In December 2019,coronavirus disease 2019(COVID-19)caused by a novel coronavirus(SARS-CoV-2)broke out in Wuhan,China,and has spread widely all over the world,reaching the pandemic level.[1]According to the latest WHO report,693,224 cases of COVID-19 were confirmed globally as of March 30,2020,with more than 33,000 deaths.[2]Because COVID-19 is highly contagious and harmful,it is crucial to determine the predictors of severe infection and death for risk stratification and guiding clinical treatment and intervention.
基金financially supported by the Fundamental Research Funds for the Central Universities(Grant Nos.N160704003,N170708020,N2107007).
文摘Angular rolling technology can overcome the size limitation of plate mill equipment and product heavy steel plate with large unit weight or improve the production efficiency of small width spreading ratio product.With the DEFORM software,the numerical simulation study of the angular rolling process was carried out,and the relation laws of the width,rolling force and strain of the rolled piece under different angular rolling process conditions were obtained.The simulation results show that with the rotation angle increasing,the width of the rolled piece increases.Comparing with the conventional rolling process,the rolling force changes gradually during the biting and throwing stage of the angular rolling pass.With the rotation angle increasing,both the equivalent strains in the thickness direction and in the width direction gradually increase.According to the pattern and dimension's changing formula in the double-pass angular rolling process,the prediction model of angle,reduction and width spreading is built.The opening value of side guide is set for the rotation angle controlling.For one 5000 mm heavy plate mill,the automation control system was modified,and the angular rolling technology was applied online.The absolute deviation of target width does not exceed±20 mm and the relative deviation does not exceed 1%.The large unit weight plate that cannot be rolled with traditional process,can be produced now,and the annual output increases by 10000 t.
