In this paper,15Cr-ODS steels containing 0,1 wt%,2 wt%and 3 wt%Al element were fabricated by combining wet-milling and spark plasma sintering(SPS)methods.The microstructure and mechanical properties of ODS steel were ...In this paper,15Cr-ODS steels containing 0,1 wt%,2 wt%and 3 wt%Al element were fabricated by combining wet-milling and spark plasma sintering(SPS)methods.The microstructure and mechanical properties of ODS steel were investigated by XRD,SEM,TEM,EBSD and tensile tests.The results demonstrate that the Al addition significantly refines the particle precipitates in the Fe-Cr matrix,leading to the obvious refinement in grain size of matrix and the improvement of mechanical properties.The dispersion particles in ODS steels with Al addition are identified as Al2O3 and Y_(2)Ti_(2)O_(7)nanoparticles,which has a heterogeneous size distribution in the range of 5 nm to 300 nm.Increasing Al addition causes an obvious increase in tensile strength and a decline in elongation.The tensile strength and elongation of 15Cr-ODS steel containing 3 wt%Al are 775.3 MPa and 15.1%,respectively.The existence of Al element improves the corrosion resistance of materials.The ODS steel containing 2 wt%Al shows corrosion potential of 0.39 V and passivation current density of 2.61×10^(−3)A/cm^(2)(1.37 V).This work shows that Al-doped ODS steels prepared by wet-milling and SPS methods have a potential application in structural parts for nuclear system.展开更多
Aim: The aim of this paper is to summarize the experience and results of deep vein thrombosis prevention after standardized abdominal tumor resection and lymph node dissection, and to investigate standardized treatmen...Aim: The aim of this paper is to summarize the experience and results of deep vein thrombosis prevention after standardized abdominal tumor resection and lymph node dissection, and to investigate standardized treatment methods for postoperative thrombosis prevention. Methods: We performed a retrospective analysis of the clinical data for 548 patients who were given low molecular weight heparin, low molecular weight dextran, or IV salvia to prevent thrombosis development between January 2007 and April 2010 after standardized abdominal tumor resection and lymph node dissection. Patients were divided into the following three groups based on the treatment period and treatment schedule: group 1 included 163 patients who had been treated between January 2007 and March 2008 and received a 7-day course of daily low molecular weight dextran (500 mL) and salvia injection (0.2 g) postoperatively;group 2 included 149 patients who had been treated between April 2008 and March 2009 and received a 7-day course of daily low molecular weight dextran (500 mL), salvia injection (0.2 g), and low molecular weight heparin (40 mg) postoperatively;group 3 included 236 patients who had been treated between April 2009 and April 2010 and postoperatively received a 7-day course of daily low molecular weight dextran (500 mL) and salvia injection (0.2 g), and on postoperative day 3 were started on an additional 7-day course of daily low molecular weight heparin (40 mg). Then, we performed comparative analysis of the treatment efficacy and concomitant symptoms. Results: In group 1, 64 of the 163 cases (39.3%) were positive for D-dimer, and 15 (9.2%) cases were positive for DVT based on Doppler imaging of the lower extremities. In group 2, 38 cases (25.5%) were positive for D-dimer and 3 cases (2.0%) for DVT. In group 3, 62 cases (26.3%) were positive for D-dimer and 6 cases (2.5%) for DVT. In general, the administration of low molecular weight heparin for anticoagulation in groups 2 and 3 led to significant reduction of thromboses when compared to group 1. However, altering the initiation day of low molecular weight heparin administration between groups 2 and 3 did not result in significant differences in the rate of thrombosis formation. Through clinical observation, early administration of low molecular weight heparin may increase adverse effects. Conclusion: We have demonstrated the superior efficacy of postoperative administration of low molecular weight dextran and IV salvia with additional subcutaneous injection of low molecular weight heparin on postoperative day 3 to prevent DVT development after radical resection of abdominal tumors.展开更多
基金Project(2020JJ2001)supported by Outstanding Youth Scientist Foundation of Hunan Province,ChinaProject(6142912200102)supported by Foundation for National Key Laboratory of Science and Technology on Highstrength Structural Materials,China。
文摘In this paper,15Cr-ODS steels containing 0,1 wt%,2 wt%and 3 wt%Al element were fabricated by combining wet-milling and spark plasma sintering(SPS)methods.The microstructure and mechanical properties of ODS steel were investigated by XRD,SEM,TEM,EBSD and tensile tests.The results demonstrate that the Al addition significantly refines the particle precipitates in the Fe-Cr matrix,leading to the obvious refinement in grain size of matrix and the improvement of mechanical properties.The dispersion particles in ODS steels with Al addition are identified as Al2O3 and Y_(2)Ti_(2)O_(7)nanoparticles,which has a heterogeneous size distribution in the range of 5 nm to 300 nm.Increasing Al addition causes an obvious increase in tensile strength and a decline in elongation.The tensile strength and elongation of 15Cr-ODS steel containing 3 wt%Al are 775.3 MPa and 15.1%,respectively.The existence of Al element improves the corrosion resistance of materials.The ODS steel containing 2 wt%Al shows corrosion potential of 0.39 V and passivation current density of 2.61×10^(−3)A/cm^(2)(1.37 V).This work shows that Al-doped ODS steels prepared by wet-milling and SPS methods have a potential application in structural parts for nuclear system.
文摘Aim: The aim of this paper is to summarize the experience and results of deep vein thrombosis prevention after standardized abdominal tumor resection and lymph node dissection, and to investigate standardized treatment methods for postoperative thrombosis prevention. Methods: We performed a retrospective analysis of the clinical data for 548 patients who were given low molecular weight heparin, low molecular weight dextran, or IV salvia to prevent thrombosis development between January 2007 and April 2010 after standardized abdominal tumor resection and lymph node dissection. Patients were divided into the following three groups based on the treatment period and treatment schedule: group 1 included 163 patients who had been treated between January 2007 and March 2008 and received a 7-day course of daily low molecular weight dextran (500 mL) and salvia injection (0.2 g) postoperatively;group 2 included 149 patients who had been treated between April 2008 and March 2009 and received a 7-day course of daily low molecular weight dextran (500 mL), salvia injection (0.2 g), and low molecular weight heparin (40 mg) postoperatively;group 3 included 236 patients who had been treated between April 2009 and April 2010 and postoperatively received a 7-day course of daily low molecular weight dextran (500 mL) and salvia injection (0.2 g), and on postoperative day 3 were started on an additional 7-day course of daily low molecular weight heparin (40 mg). Then, we performed comparative analysis of the treatment efficacy and concomitant symptoms. Results: In group 1, 64 of the 163 cases (39.3%) were positive for D-dimer, and 15 (9.2%) cases were positive for DVT based on Doppler imaging of the lower extremities. In group 2, 38 cases (25.5%) were positive for D-dimer and 3 cases (2.0%) for DVT. In group 3, 62 cases (26.3%) were positive for D-dimer and 6 cases (2.5%) for DVT. In general, the administration of low molecular weight heparin for anticoagulation in groups 2 and 3 led to significant reduction of thromboses when compared to group 1. However, altering the initiation day of low molecular weight heparin administration between groups 2 and 3 did not result in significant differences in the rate of thrombosis formation. Through clinical observation, early administration of low molecular weight heparin may increase adverse effects. Conclusion: We have demonstrated the superior efficacy of postoperative administration of low molecular weight dextran and IV salvia with additional subcutaneous injection of low molecular weight heparin on postoperative day 3 to prevent DVT development after radical resection of abdominal tumors.
