Achieving a homogeneous equiaxed grain structure and breaking the strength–ductility trade-off in additively manufactured aluminum alloys is a great challenge.In this paper,we propose a novel duplex nucleation mechan...Achieving a homogeneous equiaxed grain structure and breaking the strength–ductility trade-off in additively manufactured aluminum alloys is a great challenge.In this paper,we propose a novel duplex nucleation mechanism that combines ex situ TiB_(2) and in situ Al_(3)Ti for controlling the grain structure of additively manufactured AlCuMgTi-TiB_(2) composites.We conducted thermodynamic calculations and phase-field simulations to elucidate the duplex nucleation-based grain structure control.The Al_(3)Ti-coated TiB_(2) inoculant system formed via duplex nucleation during solidification enabled the formation of a ho-mogeneous ultrafine equiaxed microstructure in both the as-fabricated and heat-treated states.Different from the AlCuMgTi alloy,the TiB_(2)-reinforced AlCuMgTi composites produced via laser powder bed fusion were amenable to the simultaneous enhancement of strength and ductility.The proposed alloy design approach and duplex nucleation mechanism can guide the tailoring of the microstructure and mechanical properties of additively manufactured aluminum parts.展开更多
The maize quadraplex tetraploids and duplex tetraploids were developed using Kato’s protocols. The phenotype ofheterosis and inbreeding depression over generations in their parents and progenies of F1, F2 and F3 were...The maize quadraplex tetraploids and duplex tetraploids were developed using Kato’s protocols. The phenotype ofheterosis and inbreeding depression over generations in their parents and progenies of F1, F2 and F3 were investigated.The results indicated that different duplex tetraploids have different genetic backgrounds, but they acquire maximumheterosis at same traits, such as the leaf length, leaf width, culm circumference and days to flowering. P.N. rises muchfaster from the F2 to F3 segment than the A.W. does for the plant height in duplex tetraploids. In comparing duplex andquadraplex over a generation the quadriplex is showing the greatest heterosis in plant height, leaf height, leaf width anddays to flowering. Most of the examples achieve the maximum heterosis at Qu F2, with the exception of culm circumference,which achieves greatest heterosis at PNAW F1. Meanwhile, this experiment shows that quadraplex tetraploids has distinctadditional favorable alleles that are not contained in duplex tetraploid, this is demonstrated by the heterosis found incrosses between the two duplex tetraploid. This finding helps explain quadraploids superiority and unique breedingbehavior, in which, the progressive heterosis and inbreeding depression in maize are due mainly to linkage disequilibrium.The severe inbreeding depression in duplex tetraploids is due mainly to the rapid loss of complementary chromosomes orgenes interactions in the first few generation of inbreeding. Correspondingly, the progressive heterosis in quadraplextetraploids is due mainly to a progressive increase in complementarities of homologous chromosomes or genes interactions.Greater complementarities of homologous chromosomes or genes interactions in tetraploids maize alse helps explainrecent molecular biology research indicating that some of traits in quadraplex tetraploids are more responsive to geneticdiversity than in duplex tetraploids. In addition, the dosage effect of polyploid in relation to the genetic basis of heterosisand inbreeding depression were discussed also.展开更多
体声波(BAW)双工器中Rx滤波器对Tx滤波器的负载效应,会使Tx滤波器的插入损耗性能退化而带外抑制性能过剩,进而使得BAW双工器性能不佳。为了解决这一问题,提出了一种BAW双工器的优化设计方法。设置BAW双工器中Tx滤波器的串联薄膜体声波...体声波(BAW)双工器中Rx滤波器对Tx滤波器的负载效应,会使Tx滤波器的插入损耗性能退化而带外抑制性能过剩,进而使得BAW双工器性能不佳。为了解决这一问题,提出了一种BAW双工器的优化设计方法。设置BAW双工器中Tx滤波器的串联薄膜体声波谐振器(FBAR)单元谐振区面积,及并联FBAR单元与串联FBAR单元谐振区面积比值为两组优化变量,通过牺牲Tx滤波器过剩带外抑制性能的方式,采用基于梯度的优化算法计算得到了两组优化变量的最终取值。以一个工作在FDD-LTE band 7的BAW双工器优化设计案例展示了该方法的应用流程。优化设计结果的仿真验证表明,Tx滤波器的插入损耗性能从2dB提升至1.1dB,带内波动性能从1dB提升至0.3dB。由此验证了该方法的可行性。展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52275331 and 52205358)the China Postdoctoral Science Foundation(No.2021M701293)+4 种基金the State Key Laboratory of Powder Metallurgy(Central South University,Changsha,China)the State Key Laboratory of Advanced Welding and Joining(Harbin Institute of Technology,Harbin,China)the Key-Area Research and Development Program of Guangdong Province(No.2020B090923001)the Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project(No.HZQB-KCZYB-2020030)the Academic Frontier Youth Team(No.2018QYTD04)at the Huazhong University of Science and Technology.
文摘Achieving a homogeneous equiaxed grain structure and breaking the strength–ductility trade-off in additively manufactured aluminum alloys is a great challenge.In this paper,we propose a novel duplex nucleation mechanism that combines ex situ TiB_(2) and in situ Al_(3)Ti for controlling the grain structure of additively manufactured AlCuMgTi-TiB_(2) composites.We conducted thermodynamic calculations and phase-field simulations to elucidate the duplex nucleation-based grain structure control.The Al_(3)Ti-coated TiB_(2) inoculant system formed via duplex nucleation during solidification enabled the formation of a ho-mogeneous ultrafine equiaxed microstructure in both the as-fabricated and heat-treated states.Different from the AlCuMgTi alloy,the TiB_(2)-reinforced AlCuMgTi composites produced via laser powder bed fusion were amenable to the simultaneous enhancement of strength and ductility.The proposed alloy design approach and duplex nucleation mechanism can guide the tailoring of the microstructure and mechanical properties of additively manufactured aluminum parts.
基金This study was in part supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars of Education Ministry of Chinaa grant from the Department of Energy Biosciences,USA,to University of Columbia,JB.
文摘The maize quadraplex tetraploids and duplex tetraploids were developed using Kato’s protocols. The phenotype ofheterosis and inbreeding depression over generations in their parents and progenies of F1, F2 and F3 were investigated.The results indicated that different duplex tetraploids have different genetic backgrounds, but they acquire maximumheterosis at same traits, such as the leaf length, leaf width, culm circumference and days to flowering. P.N. rises muchfaster from the F2 to F3 segment than the A.W. does for the plant height in duplex tetraploids. In comparing duplex andquadraplex over a generation the quadriplex is showing the greatest heterosis in plant height, leaf height, leaf width anddays to flowering. Most of the examples achieve the maximum heterosis at Qu F2, with the exception of culm circumference,which achieves greatest heterosis at PNAW F1. Meanwhile, this experiment shows that quadraplex tetraploids has distinctadditional favorable alleles that are not contained in duplex tetraploid, this is demonstrated by the heterosis found incrosses between the two duplex tetraploid. This finding helps explain quadraploids superiority and unique breedingbehavior, in which, the progressive heterosis and inbreeding depression in maize are due mainly to linkage disequilibrium.The severe inbreeding depression in duplex tetraploids is due mainly to the rapid loss of complementary chromosomes orgenes interactions in the first few generation of inbreeding. Correspondingly, the progressive heterosis in quadraplextetraploids is due mainly to a progressive increase in complementarities of homologous chromosomes or genes interactions.Greater complementarities of homologous chromosomes or genes interactions in tetraploids maize alse helps explainrecent molecular biology research indicating that some of traits in quadraplex tetraploids are more responsive to geneticdiversity than in duplex tetraploids. In addition, the dosage effect of polyploid in relation to the genetic basis of heterosisand inbreeding depression were discussed also.
文摘体声波(BAW)双工器中Rx滤波器对Tx滤波器的负载效应,会使Tx滤波器的插入损耗性能退化而带外抑制性能过剩,进而使得BAW双工器性能不佳。为了解决这一问题,提出了一种BAW双工器的优化设计方法。设置BAW双工器中Tx滤波器的串联薄膜体声波谐振器(FBAR)单元谐振区面积,及并联FBAR单元与串联FBAR单元谐振区面积比值为两组优化变量,通过牺牲Tx滤波器过剩带外抑制性能的方式,采用基于梯度的优化算法计算得到了两组优化变量的最终取值。以一个工作在FDD-LTE band 7的BAW双工器优化设计案例展示了该方法的应用流程。优化设计结果的仿真验证表明,Tx滤波器的插入损耗性能从2dB提升至1.1dB,带内波动性能从1dB提升至0.3dB。由此验证了该方法的可行性。
