The microstructure of an alloy is affected intensively by the cooling process.To figure out the inherent relation between the cooling rate and microstructure of an advanced nickel-based superalloy,experimental and num...The microstructure of an alloy is affected intensively by the cooling process.To figure out the inherent relation between the cooling rate and microstructure of an advanced nickel-based superalloy,experimental and numerical studies on the cooling process were conducted.Specifically,the measurement was performed concerning both the temperature of the specimen during the end-quench test and the size of the secondaryγ′phase of the specimen after that.The heat transfer coefficient of the quenched surface was determined by the inverse heat transfer method for simulation.The results show that the cooling rate of the quenched surface exceeds 1574 K/min.Based on the averaged cooling rate obtained from the simulation and the measured size of the secondaryγ′phase,an empirical correlation in a double logarithmic relationship between them is proposed.The relationship is verified by the experiment with specified cooling rates.展开更多
The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to underst...The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to understand the complicated phenomena ofelectrolyte flow behavior in vertical counter electrodes in full-scale copper ER cell,the three-dimensional computational fluiddynamics(CFD)models with four different arrangements of electrolyte inlets,i.e.,single inlet(SI),central bottom inlets(CBI),topside interlaced inlets(TII),and bottom side interlaced inlets(BII),were established to simulate the flow behavior.Simulation resultshave revealed that the parallel injection devices help to improve the electrolyte velocity between electrodes,and while the relativerange of electrolyte velocity in CBI exceeds that of TII and BII,which is more than4times,indicating its severer unequal flowdistribution.Meanwhile,the average velocity of electrolyte in BII is4times larger than that of SI due to its higher turbulenceintensity.Generally,one of the efficient ways to supply fresh copper solution rapidly and uniformly into the inter-electrode space is toadapt the arrangement of BII.By utilizing such an arrangement,the electro-refining under high electrical current density is possible,and the productivity can be increased in sequence.展开更多
随着现代生活观念的改变,人工流产等宫腔操作增多,宫腔粘连(Intrauterine Adhesions,IUA)的发病率随即增加,严重影响女性的身心健康。目前,宫腔镜下粘连分离术(Transcervical Resection of Adhesions,TCRA)是其首选治疗方法,虽然治疗效...随着现代生活观念的改变,人工流产等宫腔操作增多,宫腔粘连(Intrauterine Adhesions,IUA)的发病率随即增加,严重影响女性的身心健康。目前,宫腔镜下粘连分离术(Transcervical Resection of Adhesions,TCRA)是其首选治疗方法,虽然治疗效果较好,但术后再粘连率仍偏高。因此,预防再粘连一直是IUA治疗的难点。文章综合分析中西医对IUA的认识及防治的相关研究进展,以期促进改善临床对治疗IUA患者效果,减少再次粘连,并提高妊娠率。展开更多
基金Project(2016YFB0700300) supported by the National Key Research and Development Program of ChinaProject(2019zzts262) supported by the Postgraduate Independent Exploration and Innovation Program of Central South University,China
文摘The microstructure of an alloy is affected intensively by the cooling process.To figure out the inherent relation between the cooling rate and microstructure of an advanced nickel-based superalloy,experimental and numerical studies on the cooling process were conducted.Specifically,the measurement was performed concerning both the temperature of the specimen during the end-quench test and the size of the secondaryγ′phase of the specimen after that.The heat transfer coefficient of the quenched surface was determined by the inverse heat transfer method for simulation.The results show that the cooling rate of the quenched surface exceeds 1574 K/min.Based on the averaged cooling rate obtained from the simulation and the measured size of the secondaryγ′phase,an empirical correlation in a double logarithmic relationship between them is proposed.The relationship is verified by the experiment with specified cooling rates.
基金Project(61321003)supported by the National Natural Science Foundation of China
文摘The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to understand the complicated phenomena ofelectrolyte flow behavior in vertical counter electrodes in full-scale copper ER cell,the three-dimensional computational fluiddynamics(CFD)models with four different arrangements of electrolyte inlets,i.e.,single inlet(SI),central bottom inlets(CBI),topside interlaced inlets(TII),and bottom side interlaced inlets(BII),were established to simulate the flow behavior.Simulation resultshave revealed that the parallel injection devices help to improve the electrolyte velocity between electrodes,and while the relativerange of electrolyte velocity in CBI exceeds that of TII and BII,which is more than4times,indicating its severer unequal flowdistribution.Meanwhile,the average velocity of electrolyte in BII is4times larger than that of SI due to its higher turbulenceintensity.Generally,one of the efficient ways to supply fresh copper solution rapidly and uniformly into the inter-electrode space is toadapt the arrangement of BII.By utilizing such an arrangement,the electro-refining under high electrical current density is possible,and the productivity can be increased in sequence.
文摘随着现代生活观念的改变,人工流产等宫腔操作增多,宫腔粘连(Intrauterine Adhesions,IUA)的发病率随即增加,严重影响女性的身心健康。目前,宫腔镜下粘连分离术(Transcervical Resection of Adhesions,TCRA)是其首选治疗方法,虽然治疗效果较好,但术后再粘连率仍偏高。因此,预防再粘连一直是IUA治疗的难点。文章综合分析中西医对IUA的认识及防治的相关研究进展,以期促进改善临床对治疗IUA患者效果,减少再次粘连,并提高妊娠率。
