The electromagnetic direct chill （EMDC） casting process is a welt-established production route for aluminum alloy ingot, however, the skin effect restricts the casting diameter. In order to avoid this problem, annul...The electromagnetic direct chill （EMDC） casting process is a welt-established production route for aluminum alloy ingot, however, the skin effect restricts the casting diameter. In order to avoid this problem, annulus electromagnetic direct chill （A-EMDC） casting process has been developed. A three-dimension finite element computational model of A-EMDC casting process was established by using ANSYS Magnetic-Nodal programs and FLOTRAN CFD programs. Microstruetures of A-EMDC casting semi-solid Al-6Si-3Cu-Mg alloy billets were investigated. Two pairs of vortexes occur within the crystallizer with opposite direction in A-EMDC. The annulus gap is advantageous to increasing circulate flow, reducing the temperature gradient as well as shallowing liquid sump depth. The microstructure obtained by A-EMDC is globular or rosette-like, and the microstructure is homogeneous in the billet.展开更多
To shorten the preparation process of semi-solid billets,semi-solid billets of 2A14 aluminum alloy were prepared by wrought aluminum directly semi-solid isothermal treatment(WADSSIT)process.Three-dimension(3D)combined...To shorten the preparation process of semi-solid billets,semi-solid billets of 2A14 aluminum alloy were prepared by wrought aluminum directly semi-solid isothermal treatment(WADSSIT)process.Three-dimension(3D)combined microstructure evolution,namely transverse direction(TD)surface,rolling direction(RD)surface,and normal direction(ND)surface,was studied.Effects of temperature and holding time on average grain size and average shape factor were investigated.The results showed that the optimum conditions for preparation of 2A14 semi-solid billets by this process were 615℃ and 20 min(average grain size of 124μm and shape factor of 0.81).Electron backscatter diffraction(EBSD)observations indicated that the microstructure was completely recrystallized when it was heated to 600℃.Grain size was increased with the increase of temperature and grew up slowly with the holding time prolonging.Roundness was increased with increase of holding time but was not sensitive to temperature.展开更多
文摘目的:分析胃癌石蜡组织BRCA1、hENT1、Topo1 mRNA水平与新鲜胃癌组织多西紫杉醇、吉西他滨、伊立替康体外药物敏感性的关系。方法:收集36例经病理确诊的新鲜胃癌标本,采用三维微组织块培养法(HDRA)行三种药物的体外药物敏感试验。实时荧光定量PCR检测对应胃癌石蜡组织中BRCA1、hENT1、To-po1 mRNA水平。结果:新鲜胃癌组织对三种药物的敏感性均与临床特征无明显相关性。对应胃癌石蜡组织中BRCA1、hENT1、Topo1 mRNA水平与临床特征无明显相关性。在胃癌组织中,hENT1 mRNA水平最高,BRCA1 mRNA水平最低。胃癌石蜡组织BRCA1 mRNA水平与新鲜胃癌组织的多西紫杉醇敏感性正相关(7.927 vs 3.464,P=0.001);hENT1 mRNA水平在吉西他滨敏感组高于耐药组(15.710 vs 10.145,P=0.243),Topo1 mRNA水平在伊立替康敏感组高于耐药组(10.024 vs 6.038,P=0.124),但均未达统计学差异。结论:胃癌石蜡组织BRCA1mRNA水平与新鲜胃癌组织对多西紫杉醇的敏感性呈正相关。
基金Project(2009AA03Z534) supported by the National Hi-tech Research and Development Program of ChinaProject(2006CB605203) supported by the National Basic Research Program of China
文摘The electromagnetic direct chill （EMDC） casting process is a welt-established production route for aluminum alloy ingot, however, the skin effect restricts the casting diameter. In order to avoid this problem, annulus electromagnetic direct chill （A-EMDC） casting process has been developed. A three-dimension finite element computational model of A-EMDC casting process was established by using ANSYS Magnetic-Nodal programs and FLOTRAN CFD programs. Microstruetures of A-EMDC casting semi-solid Al-6Si-3Cu-Mg alloy billets were investigated. Two pairs of vortexes occur within the crystallizer with opposite direction in A-EMDC. The annulus gap is advantageous to increasing circulate flow, reducing the temperature gradient as well as shallowing liquid sump depth. The microstructure obtained by A-EMDC is globular or rosette-like, and the microstructure is homogeneous in the billet.
基金financially supported by the National Natural Science Foundation of China (No.51875124)the National Key Research and Development Project,China (No.2019YFB2006503)。
文摘To shorten the preparation process of semi-solid billets,semi-solid billets of 2A14 aluminum alloy were prepared by wrought aluminum directly semi-solid isothermal treatment(WADSSIT)process.Three-dimension(3D)combined microstructure evolution,namely transverse direction(TD)surface,rolling direction(RD)surface,and normal direction(ND)surface,was studied.Effects of temperature and holding time on average grain size and average shape factor were investigated.The results showed that the optimum conditions for preparation of 2A14 semi-solid billets by this process were 615℃ and 20 min(average grain size of 124μm and shape factor of 0.81).Electron backscatter diffraction(EBSD)observations indicated that the microstructure was completely recrystallized when it was heated to 600℃.Grain size was increased with the increase of temperature and grew up slowly with the holding time prolonging.Roundness was increased with increase of holding time but was not sensitive to temperature.
