An ultrafine lamellar-structured martensite steel fabricated by heavy warm rolling(HWR)has shown an excellent combination of strength and ductility.By appending tempering at 400℃to HWR,we show that the comprehensive ...An ultrafine lamellar-structured martensite steel fabricated by heavy warm rolling(HWR)has shown an excellent combination of strength and ductility.By appending tempering at 400℃to HWR,we show that the comprehensive mechanical property of a lamellar-structured low-carbon martensite steel can be further improved to reach a yield strength of~1.8 GPa,an ultimate tensile strength of~2.0 GPa and a total elongation of~9.3%.This is achieved by tempering the HWR steel from 300 to 750℃,and the optimum tempering temperature is thus obtained.We find that the tempered ultrafine lamellar martensite contains high-density nanoprecipitates dispersed within the aligned martensite laths with reduced crystallographic variations.The ultrahigh strength of the steel is rationalized as mainly the result of grain boundary strengthening and precipitation strengthening,which contribute to yield stress by 610 MPa and 440 MPa,respectively.The good ductility is believed to be closely related to the capacity of the tempered grains to accommodate dense dislocations upon plastic deformation.The present thermomechanical processing provides a feasible routine for producing steels with ultrahigh-strength and good-ductility.展开更多
Background:Acute decompensated heart failure(ADHF)is a life-threatening and costly disease.Controversy re-mains regarding the effi cacy and renal tolerability of ultrafi ltration for treating ADHF.We therefore perform...Background:Acute decompensated heart failure(ADHF)is a life-threatening and costly disease.Controversy re-mains regarding the effi cacy and renal tolerability of ultrafi ltration for treating ADHF.We therefore performed this meta-analysis to evaluate this clinical issue.Methods:A search of PubMed,EMBASE,and the Cochrane database of controlled trials was performed from in-ception to March 2021 for relevant randomized controlled trials.The quality of the included trials and outcomes was evaluated with the use of the risk of bias assessment tool and the Grading of Recommendations,Assessment,Develop-ment and Evaluation(GRADE)approach,respectively.The risk ratio and the standardized mean difference(SMD)or weighted mean difference(WMD)were computed and pooled with fi xed-effects or random-effects models.Results:This meta-analysis included 19 studies involving 1281 patients.Ultrafi ltration was superior to the control treatments for weight loss(WMD 1.24 kg,95%confi dence interval[CI]0.38-2.09 kg,P=0.004)and fl uid removal(WMD 1.55 L,95%CI 0.51-2.59 l,P=0.003)and was associated with a signifi cant increase in serum creatinine level compared with the control treatments(SMD 0.15 mg/dL,95%CI 0.00-0.30 mg/dL,P=0.04).However,no signifi cant effects were found for serum N-terminal prohormone of brain natriuretic peptide level,length of hospital stay,all-cause mortality,or all-cause rehospitalization in the ultrafi ltration group.Conclusions:The use of ultrafi ltration in patients with ADHF is superior to the use of the control treatments for weight loss and fl uid removal,but has adverse renal effects and lacks signifi cant effects on long-term prognosis,in-dicating that this approach to decongestion in ADHF patients is effi cient for fl uid management but less safe renally.展开更多
基金funded by the National Natural Science Foundation of China(No.52071212)supported by the Innovation Program of the Shanghai Municipal Education Commission(No.2019-01-07-00-09-E00024)BAOSTEEL-SJTU Joint Research Center for Future Steel。
文摘An ultrafine lamellar-structured martensite steel fabricated by heavy warm rolling(HWR)has shown an excellent combination of strength and ductility.By appending tempering at 400℃to HWR,we show that the comprehensive mechanical property of a lamellar-structured low-carbon martensite steel can be further improved to reach a yield strength of~1.8 GPa,an ultimate tensile strength of~2.0 GPa and a total elongation of~9.3%.This is achieved by tempering the HWR steel from 300 to 750℃,and the optimum tempering temperature is thus obtained.We find that the tempered ultrafine lamellar martensite contains high-density nanoprecipitates dispersed within the aligned martensite laths with reduced crystallographic variations.The ultrahigh strength of the steel is rationalized as mainly the result of grain boundary strengthening and precipitation strengthening,which contribute to yield stress by 610 MPa and 440 MPa,respectively.The good ductility is believed to be closely related to the capacity of the tempered grains to accommodate dense dislocations upon plastic deformation.The present thermomechanical processing provides a feasible routine for producing steels with ultrahigh-strength and good-ductility.
基金funded by grants from the National Natural Science Foundation of China(no 81900631)the China Postdoctoral Science Foundation(2019M653354)+1 种基金the Natural Science Foundation Postdoctoral Program of Chongqing Science and Technology Bureau(cstc2019jcyj-bsh0012)the Kuanren Talents Program of the Second Affi liated Hospital of Chongqing Medical University.
文摘Background:Acute decompensated heart failure(ADHF)is a life-threatening and costly disease.Controversy re-mains regarding the effi cacy and renal tolerability of ultrafi ltration for treating ADHF.We therefore performed this meta-analysis to evaluate this clinical issue.Methods:A search of PubMed,EMBASE,and the Cochrane database of controlled trials was performed from in-ception to March 2021 for relevant randomized controlled trials.The quality of the included trials and outcomes was evaluated with the use of the risk of bias assessment tool and the Grading of Recommendations,Assessment,Develop-ment and Evaluation(GRADE)approach,respectively.The risk ratio and the standardized mean difference(SMD)or weighted mean difference(WMD)were computed and pooled with fi xed-effects or random-effects models.Results:This meta-analysis included 19 studies involving 1281 patients.Ultrafi ltration was superior to the control treatments for weight loss(WMD 1.24 kg,95%confi dence interval[CI]0.38-2.09 kg,P=0.004)and fl uid removal(WMD 1.55 L,95%CI 0.51-2.59 l,P=0.003)and was associated with a signifi cant increase in serum creatinine level compared with the control treatments(SMD 0.15 mg/dL,95%CI 0.00-0.30 mg/dL,P=0.04).However,no signifi cant effects were found for serum N-terminal prohormone of brain natriuretic peptide level,length of hospital stay,all-cause mortality,or all-cause rehospitalization in the ultrafi ltration group.Conclusions:The use of ultrafi ltration in patients with ADHF is superior to the use of the control treatments for weight loss and fl uid removal,but has adverse renal effects and lacks signifi cant effects on long-term prognosis,in-dicating that this approach to decongestion in ADHF patients is effi cient for fl uid management but less safe renally.
