For friction stir lap welding (FSLW) process by the rotating pin greatly inserting into the bottom plate, the bending-down morphology of hook helps to obtain a high-strength lap joint, and can be more conducive to the...For friction stir lap welding (FSLW) process by the rotating pin greatly inserting into the bottom plate, the bending-down morphology of hook helps to obtain a high-strength lap joint, and can be more conducive to the joint strength when the tensile-fractured path is located in the top plate. In light of this, the reverse-flow FSLW (RF-FSLW) by a newly designed rotating tool with a right-left threaded X-shape pin (X-pin) was employed to weld 2024-T4 aluminum alloys with the same plate thickness, and the flow field simulation, in situ tensile test and EBSD analysis were utilized to understand the relations among the formation features, the fracture features and the joint strengths. The results indicated that under the integrated effects of the bending-down shape of hook, the bulging shape of nugget zone (NZ) and the bending-up shape of beginning part of cold lap near NZ outline, the RF-FSLW joint was tensile fractured in the top plate of joint. For the RF-FSLW joint, its maximum tensile strength was 412 MPa, and the corresponding joint efficiency (92.8%) was larger than that of reported friction stir welded joint of 2024 aluminum alloys in T temper condition. The RF-FSLW technology by the right-left threaded X-pin puts forward an extremely effective way for obtaining the superb-strength lap joint of aluminum alloys.展开更多
The effect of the rotation of the earth, this non-inertial system, has beenneglected in the theories of evolution. In this article, we put forward the hypothesis thatthe Coriolis force due to the rotation of the earth...The effect of the rotation of the earth, this non-inertial system, has beenneglected in the theories of evolution. In this article, we put forward the hypothesis thatthe Coriolis force due to the rotation of the earth is the primary cause of the right-leftasymmetry of body structures of the vertebrate. Theoretical deductions were made andcompared with available observations. Generally we found no contradiction. Afterwardsways for further validation are discussed.展开更多
It is common for the rotating pin largely plunging into lower sheet to break up lap interface of Friction Stir Lap Welding(FSLW)joint,but the unavoidable up-bending morphology of hook outside Nugget Zone(NZ)largely re...It is common for the rotating pin largely plunging into lower sheet to break up lap interface of Friction Stir Lap Welding(FSLW)joint,but the unavoidable up-bending morphology of hook outside Nugget Zone(NZ)largely reduces the joint bearing ability.Based on the novel Opposite-directions Flowing FSLW(OF-FSLW)by the self-developed rotating tool with an Xshaped right-left thread pin,the 2024 aluminum alloys lap joint was successfully welded in this study.The migration law of lap interface during welding was investigated by the experimental and numerical methods,and then how the rotating pin and its rotating velocity affect the formation and strength of OF-FSLW joint was further analyzed.The results show that the Material Concentrated Zone(MCZ)which formed above the original lap interface made the hook bend downward,the NZ greatly enlarged and the beginning part of cold lap compressed and thickened,thereby heightening the joint bearing ability.For the OF-FSLW joint,its maximum tensile strength was403 MPa,and the corresponding joint efficiency of 90.8%was an incredible and superb value for the 2000 series heat-treatment strengthened aluminum alloys friction stir welded joint.The OF-FSLW technology by the rotating tool with an X-shaped right-left thread pin is proven to be a greatly effective approach for manufacturing the aluminum alloys lap joint with superb strength.展开更多
探讨不同激发方式在右心声学造影(agitated saline contrast echocardiography,ASCE)诊断卵圆孔未闭(patent foramen ovale,PFO)合并右向左分流(right to left shunt,RLS)中的作用。纳入2023年1月—2024年6月于川北医学院附属医院心内...探讨不同激发方式在右心声学造影(agitated saline contrast echocardiography,ASCE)诊断卵圆孔未闭(patent foramen ovale,PFO)合并右向左分流(right to left shunt,RLS)中的作用。纳入2023年1月—2024年6月于川北医学院附属医院心内科就诊的328例疑似PFO患者,采用咳嗽、改良蹲立动作、束臂试验及联合激发,以经食管超声(TEE)为金标准,比较不同方式的诊断效能。结果显示,束臂试验对中-大量RLS的检出率(45.8%)高于咳嗽(28.9%)和改良蹲立动作(35.4%);二阶法中咳嗽+束臂试验的检出率最高(52.1%),三阶法的检出率(54.3%)未显著提升但稳定性更佳;束臂试验及三阶法的AUC分别为0.842和0.891,显著优于单一激发。研究发现,束臂试验及联合激发可提高PFO-RLS检出率,推荐将其作为个体化联合方案以优化诊断效能。展开更多
基金supported by the National Natural Sci-ence Foundation of China(Nos.52074184 and 52374393)the Natu-ral Science Foundation Project of Liaoning Province(No.2023-MS-238)+1 种基金Liaoning Revitalization Talents Program(No.XLYC2203009)the Fundamental Research Funds for the Universities of Liaon-ing Province.
文摘For friction stir lap welding (FSLW) process by the rotating pin greatly inserting into the bottom plate, the bending-down morphology of hook helps to obtain a high-strength lap joint, and can be more conducive to the joint strength when the tensile-fractured path is located in the top plate. In light of this, the reverse-flow FSLW (RF-FSLW) by a newly designed rotating tool with a right-left threaded X-shape pin (X-pin) was employed to weld 2024-T4 aluminum alloys with the same plate thickness, and the flow field simulation, in situ tensile test and EBSD analysis were utilized to understand the relations among the formation features, the fracture features and the joint strengths. The results indicated that under the integrated effects of the bending-down shape of hook, the bulging shape of nugget zone (NZ) and the bending-up shape of beginning part of cold lap near NZ outline, the RF-FSLW joint was tensile fractured in the top plate of joint. For the RF-FSLW joint, its maximum tensile strength was 412 MPa, and the corresponding joint efficiency (92.8%) was larger than that of reported friction stir welded joint of 2024 aluminum alloys in T temper condition. The RF-FSLW technology by the right-left threaded X-pin puts forward an extremely effective way for obtaining the superb-strength lap joint of aluminum alloys.
文摘The effect of the rotation of the earth, this non-inertial system, has beenneglected in the theories of evolution. In this article, we put forward the hypothesis thatthe Coriolis force due to the rotation of the earth is the primary cause of the right-leftasymmetry of body structures of the vertebrate. Theoretical deductions were made andcompared with available observations. Generally we found no contradiction. Afterwardsways for further validation are discussed.
基金supported by the National Natural Science Foundation of China(Nos.51874201 and 52074184)Natural Science Foundation project of Liaoning Province(2023-MS238)+1 种基金Liaoning Revitalization talents program(XLYC2203009)the Fundamental Research Funds for the Universities of Liaoning Province。
文摘It is common for the rotating pin largely plunging into lower sheet to break up lap interface of Friction Stir Lap Welding(FSLW)joint,but the unavoidable up-bending morphology of hook outside Nugget Zone(NZ)largely reduces the joint bearing ability.Based on the novel Opposite-directions Flowing FSLW(OF-FSLW)by the self-developed rotating tool with an Xshaped right-left thread pin,the 2024 aluminum alloys lap joint was successfully welded in this study.The migration law of lap interface during welding was investigated by the experimental and numerical methods,and then how the rotating pin and its rotating velocity affect the formation and strength of OF-FSLW joint was further analyzed.The results show that the Material Concentrated Zone(MCZ)which formed above the original lap interface made the hook bend downward,the NZ greatly enlarged and the beginning part of cold lap compressed and thickened,thereby heightening the joint bearing ability.For the OF-FSLW joint,its maximum tensile strength was403 MPa,and the corresponding joint efficiency of 90.8%was an incredible and superb value for the 2000 series heat-treatment strengthened aluminum alloys friction stir welded joint.The OF-FSLW technology by the rotating tool with an X-shaped right-left thread pin is proven to be a greatly effective approach for manufacturing the aluminum alloys lap joint with superb strength.
文摘探讨不同激发方式在右心声学造影(agitated saline contrast echocardiography,ASCE)诊断卵圆孔未闭(patent foramen ovale,PFO)合并右向左分流(right to left shunt,RLS)中的作用。纳入2023年1月—2024年6月于川北医学院附属医院心内科就诊的328例疑似PFO患者,采用咳嗽、改良蹲立动作、束臂试验及联合激发,以经食管超声(TEE)为金标准,比较不同方式的诊断效能。结果显示,束臂试验对中-大量RLS的检出率(45.8%)高于咳嗽(28.9%)和改良蹲立动作(35.4%);二阶法中咳嗽+束臂试验的检出率最高(52.1%),三阶法的检出率(54.3%)未显著提升但稳定性更佳;束臂试验及三阶法的AUC分别为0.842和0.891,显著优于单一激发。研究发现,束臂试验及联合激发可提高PFO-RLS检出率,推荐将其作为个体化联合方案以优化诊断效能。
