A new severe plastic deformation （SPD） method that is extrusion-shearing （ES）, which includes initial forward extrusion and shearing process subsequently, was developed to fabricate the fine grained AZ31 Mg alloys...A new severe plastic deformation （SPD） method that is extrusion-shearing （ES）, which includes initial forward extrusion and shearing process subsequently, was developed to fabricate the fine grained AZ31 Mg alloys. The components of ES die were manufactured and installed to gleeble1500D thermo-mechanical simulator. Microstructure observations were carried out in different positions of ES formed rods. The results show that homogeneous microstructures with mean grain size of 2 μm are obtained at lower temperature as the accumulated true strain is 2.44. Occurring of continuous dynamic recrystallization （DRX） is the main reason for grain refinement during ES process. The experimental results show that the ES process effectively refines the grains of AZ31 magnesium. The production results of ES extrusion with industrial extruder under different extrusion conditions show that the ES extrusion can be applied in large-scale industry.展开更多
As-cast Mg-6Zn-xCu-0.6Zr(x=0,0.5,1.0,wt.%)alloys were fabricated by permanent mold casting;then,the alloys were subjected to homogenization heat treatment and extrusion-shearing(ES)process.The microstructure and mecha...As-cast Mg-6Zn-xCu-0.6Zr(x=0,0.5,1.0,wt.%)alloys were fabricated by permanent mold casting;then,the alloys were subjected to homogenization heat treatment and extrusion-shearing(ES)process.The microstructure and mechanical properties of the alloys were evaluated by OM,SEM/EDS,XRD,TEM,EBSD and tensile tests.The results show that the hard MgZnCu phase in Cu-added alloy can strengthen particle-stimulated nucleation(PSN)effect and hinder the migration of dynamic recrystallization(DRX)grain boundary at an elevated temperature during ES.The ZK60+0.5Cu alloy shows an optimal tensile strength–ductility combination(UTS of 396 MPa,YS of 313 MPa,andδ=20.3%)owing to strong grain boundary strengthening and improvement of Schmid factor for{0001}■basal slip.The aggregation of microvoids around the MgZnCu phase mainly accounts for the lower tensile elongation of ZK60+1.0Cu alloy compared with ZK60 alloy.展开更多
Continuous improvements in very-large-scale integration(VLSI)technology and design software have significantly broadened the scope of digital signal processing(DSP)applications.The use of application-specific integrat...Continuous improvements in very-large-scale integration(VLSI)technology and design software have significantly broadened the scope of digital signal processing(DSP)applications.The use of application-specific integrated circuits(ASICs)and programmable digital signal processors for many DSP applications have changed,even though new system implementations based on reconfigurable computing are becoming more complex.Adaptable platforms that combine hardware and software programmability efficiency are rapidly maturing with discrete wavelet transformation(DWT)and sophisticated computerized design techniques,which are much needed in today’s modern world.New research and commercial efforts to sustain power optimization,cost savings,and improved runtime effectiveness have been initiated as initial reconfigurable technologies have emerged.Hence,in this paper,it is proposed that theDWTmethod can be implemented on a fieldprogrammable gate array in a digital architecture(FPGA-DA).We examined the effects of quantization on DWTperformance in classification problems to demonstrate its reliability concerning fixed-point math implementations.The Advanced Encryption Standard(AES)algorithm for DWT learning used in this architecture is less responsive to resampling errors than the previously proposed solution in the literature using the artificial neural networks(ANN)method.By reducing hardware area by 57%,the proposed system has a higher throughput rate of 88.72%,reliability analysis of 95.5%compared to the other standard methods.展开更多
A polynomial-rooting based fourth-order cumulant algorithm is presented for direction-of-arrival（DOA） estimation of second-order fully noncircular source signals, using a uniform linear array（ULA）. This algorithm ...A polynomial-rooting based fourth-order cumulant algorithm is presented for direction-of-arrival（DOA） estimation of second-order fully noncircular source signals, using a uniform linear array（ULA）. This algorithm inherits all merits of its spectralsearching counterpart except for the applicability to arbitrary array geometry, while reducing considerably the computation cost.Simulation results show that the proposed algorithm outperforms the previously developed closed-form second-order noncircular ESPRIT method, in terms of processing capacity and DOA estimation accuracy, especially in the presence of spatially colored noise.展开更多
针对发酵过程发酵阶段具有模糊性的特点,提出了采用最小二乘支持向量机(least square support vectormachines,LS-SVM)提取并简化模糊规则的推理优化控制方法。利用能够在线测量的物理量,如CO2生成速率和NH3的添加量等,在线判定发酵过...针对发酵过程发酵阶段具有模糊性的特点,提出了采用最小二乘支持向量机(least square support vectormachines,LS-SVM)提取并简化模糊规则的推理优化控制方法。利用能够在线测量的物理量,如CO2生成速率和NH3的添加量等,在线判定发酵过程所处的阶段,然后依据加权平均的方法确定各个时刻葡萄糖的流加策略,完成了对分段连续流加补料的稳定控制。通过实际应用,证明了该方法的有效性。展开更多
基金Project (2007CB613700) supported by the National Basic Research Program of ChinaProject (50725413)supported by the National Natural Science Foundation of China+2 种基金Project (CQ CSTC,2010BB4301)supported by National Science Foundation of Chongqing, ChinaProject (CSTC2009AB4008) supported by Chongqing Sci & Tech Development Program, ChinaProject (2010CSTC-HDLS)supported by Chongqing Sci & Tech Commission, China
文摘A new severe plastic deformation （SPD） method that is extrusion-shearing （ES）, which includes initial forward extrusion and shearing process subsequently, was developed to fabricate the fine grained AZ31 Mg alloys. The components of ES die were manufactured and installed to gleeble1500D thermo-mechanical simulator. Microstructure observations were carried out in different positions of ES formed rods. The results show that homogeneous microstructures with mean grain size of 2 μm are obtained at lower temperature as the accumulated true strain is 2.44. Occurring of continuous dynamic recrystallization （DRX） is the main reason for grain refinement during ES process. The experimental results show that the ES process effectively refines the grains of AZ31 magnesium. The production results of ES extrusion with industrial extruder under different extrusion conditions show that the ES extrusion can be applied in large-scale industry.
基金Project(XLYC1807021)supported by Liaoning Revitalization Talents Program,ChinaProject(2019JH3/30100014)supported by Joint Research Fund of Lianning-Shenyang National Laboratory for Materials Science,China+2 种基金Project supported by Liaoning Bai Qian Wan Talents Program,ChinaProject(RC200414)supported by Innovation Talent Program in Sciences and Technologies for Young and Middle-aged Scientists of Shenyang City,ChinaProject(XLYC1908006)supported by High Level Innovation Team of Liaoning Province,China。
文摘As-cast Mg-6Zn-xCu-0.6Zr(x=0,0.5,1.0,wt.%)alloys were fabricated by permanent mold casting;then,the alloys were subjected to homogenization heat treatment and extrusion-shearing(ES)process.The microstructure and mechanical properties of the alloys were evaluated by OM,SEM/EDS,XRD,TEM,EBSD and tensile tests.The results show that the hard MgZnCu phase in Cu-added alloy can strengthen particle-stimulated nucleation(PSN)effect and hinder the migration of dynamic recrystallization(DRX)grain boundary at an elevated temperature during ES.The ZK60+0.5Cu alloy shows an optimal tensile strength–ductility combination(UTS of 396 MPa,YS of 313 MPa,andδ=20.3%)owing to strong grain boundary strengthening and improvement of Schmid factor for{0001}■basal slip.The aggregation of microvoids around the MgZnCu phase mainly accounts for the lower tensile elongation of ZK60+1.0Cu alloy compared with ZK60 alloy.
基金This work was supported by King Saud University for funding this work through Researchers Supporting Project number(RSP-2021/387),King Saud University,Riyadh,Saudi Arabia。
文摘Continuous improvements in very-large-scale integration(VLSI)technology and design software have significantly broadened the scope of digital signal processing(DSP)applications.The use of application-specific integrated circuits(ASICs)and programmable digital signal processors for many DSP applications have changed,even though new system implementations based on reconfigurable computing are becoming more complex.Adaptable platforms that combine hardware and software programmability efficiency are rapidly maturing with discrete wavelet transformation(DWT)and sophisticated computerized design techniques,which are much needed in today’s modern world.New research and commercial efforts to sustain power optimization,cost savings,and improved runtime effectiveness have been initiated as initial reconfigurable technologies have emerged.Hence,in this paper,it is proposed that theDWTmethod can be implemented on a fieldprogrammable gate array in a digital architecture(FPGA-DA).We examined the effects of quantization on DWTperformance in classification problems to demonstrate its reliability concerning fixed-point math implementations.The Advanced Encryption Standard(AES)algorithm for DWT learning used in this architecture is less responsive to resampling errors than the previously proposed solution in the literature using the artificial neural networks(ANN)method.By reducing hardware area by 57%,the proposed system has a higher throughput rate of 88.72%,reliability analysis of 95.5%compared to the other standard methods.
基金supported by the National Natural Science Foundation of China(617020986170209961331019)
文摘A polynomial-rooting based fourth-order cumulant algorithm is presented for direction-of-arrival（DOA） estimation of second-order fully noncircular source signals, using a uniform linear array（ULA）. This algorithm inherits all merits of its spectralsearching counterpart except for the applicability to arbitrary array geometry, while reducing considerably the computation cost.Simulation results show that the proposed algorithm outperforms the previously developed closed-form second-order noncircular ESPRIT method, in terms of processing capacity and DOA estimation accuracy, especially in the presence of spatially colored noise.
文摘针对发酵过程发酵阶段具有模糊性的特点,提出了采用最小二乘支持向量机(least square support vectormachines,LS-SVM)提取并简化模糊规则的推理优化控制方法。利用能够在线测量的物理量,如CO2生成速率和NH3的添加量等,在线判定发酵过程所处的阶段,然后依据加权平均的方法确定各个时刻葡萄糖的流加策略,完成了对分段连续流加补料的稳定控制。通过实际应用,证明了该方法的有效性。
