0引言高密度互连(high density interconnector,HDI)板出现至今已30多年,在此期间HDI板市场不断扩大,技术也不断提升。HDI板制造工艺技术种类繁多,部分因不合时宜而被淘汰了,部分得到培育而成熟延续了。因此,了解一些HDI板制造技术演变...0引言高密度互连(high density interconnector,HDI)板出现至今已30多年,在此期间HDI板市场不断扩大,技术也不断提升。HDI板制造工艺技术种类繁多,部分因不合时宜而被淘汰了,部分得到培育而成熟延续了。因此,了解一些HDI板制造技术演变知识,会对掌握HDI板技术有所启示与帮助。展开更多
Rigid-flexible composite pavement has gained significant popularity in recent decades.This paper provides a comprehensive review of the research progress concerning rigid-flexible composite pavement,aiming to promote ...Rigid-flexible composite pavement has gained significant popularity in recent decades.This paper provides a comprehensive review of the research progress concerning rigid-flexible composite pavement,aiming to promote its application and address key issues while identifying future directions.The design theory and methodology of rigid-flexible composite pavement are discussed,followed by a description of its structural and mechanical behavior characteristics.The load stress,temperature stress,and their interactive effects between the asphalt layer and the rigid base were analyzed.It is clarified that the asphalt layer serves a dual role as both a“functional layer”and a“structural layer”.Typical distresses of rigid-flexible composite pavement,which primarily occur in the asphalt layer,were discussed.These distresses include reflective cracking,top-down cracking,rutting,and compressive-shear failure.Generally,the integrity of the rigid base and the interlaminar bonding conditions significantly impact the performance and distress of the asphalt layer.The technology for enhancing the performance of rigid-flexible composite pavement is summarized in three aspects:asphalt layer properties,rigid base integrity,and interlaminar bonding condition.The study concludes that developing high-performance pavement materials based on their structural behaviors is an effective approach to improve the performance and durability of rigid-flexible composite pavement.The integrated design of structure and materials represents the future direction of road design.展开更多
盲孔在承接AI(Artificial Intelligence)服务器产品用高密度互连(High Density Interconnector,HDI)印制板层与层之间的导通上起到关键性作用。相比其他消费电子类HDI,AI服务器产品用HDI的盲孔具有高厚径比、孔径极差小、玻纤突出短等...盲孔在承接AI(Artificial Intelligence)服务器产品用高密度互连(High Density Interconnector,HDI)印制板层与层之间的导通上起到关键性作用。相比其他消费电子类HDI,AI服务器产品用HDI的盲孔具有高厚径比、孔径极差小、玻纤突出短等特点及特殊要求,为盲孔制程管控和CO_(2)激光加工技术带来更高挑战。本文围绕直径100~127μm的盲孔,研究了HDI盲孔前处理过程铜厚波动对孔径影响,分析了CO_(2)激光参数在加工不同孔径时的影响规律。最终提出了盲孔前处理过程铜厚管控标准,获得了典型盲孔孔径和介厚的最优激光参数,从而实现HDI盲孔高质量、高可靠性加工。展开更多
Artificial solid electrolyte interphase(SEI) is promising to inhibit uncontrollable lithium dendrites and enable long cycling stability for lithium metal batteries. However, the essential mechanical stability is limit...Artificial solid electrolyte interphase(SEI) is promising to inhibit uncontrollable lithium dendrites and enable long cycling stability for lithium metal batteries. However, the essential mechanical stability is limited since organic layers generally have low modulus whereas intrinsic brittleness for inorganic ones remains a great concern. Polymer-based SEIs with rigid and flexible chains in adequate mechanical properties are supposed to address this issue. Herein, a homogeneous and mechanically stable diffusion layer is achieved by blending rigid chains of polyphenylene sulfone(PPSU) with flexible chains of poly(vinylidene fluoride)(PVDF) in a hybrid membrane, enabling uniform diffusion and stabilizing the lithium metal anode. The Li||Cu cell with the protected electrode exhibits a long lifetime more than 450 cycles(0.5 m A cm^(-2), 1.0 m A h cm^(-2))(fourfold longer than the control group) with higher average Coulombic efficiency of 98.7%. Enhanced performances are also observed at Li||Li and full cell configurations. The improved performances are attributed to the controlled morphology and stable interphase, according to scanning electron microscopy(SEM) and electrochemical impedance. This research advances the idea of uniform lithium plating and provides a new insight on how to create a homogeneous and mechanically stable diffusion layer using rigid-flexible polymers.展开更多
Rail vehicles generate huge longitudinal impact loads in collisions.If unreasonable matching exists between the compressive strength of the intermediate coupler and the structural strength of the car body,the risk of ...Rail vehicles generate huge longitudinal impact loads in collisions.If unreasonable matching exists between the compressive strength of the intermediate coupler and the structural strength of the car body,the risk of car body structure damage and train derailment will increase.Herein,a four-stage rigid-flexible coupling finite element model of the coupler is established considering the coupler buckling load.The influence of the coupler buckling load on the train longitudinal-vertical-hori-zontal buckling behavior was studied,and the mechanism of the train horizontal buckling instability in train collisions was revealed.Analysis results show that an intermediate coupler should be designed to ensure that the actual buckling load is less than the compressive load when the car body structure begins to deform plastically.The actual buckling load of the coupler and the asymmetry of the structural strength of the car body in the lateral direction are two important influencing factors for the lateral buckling of a train collision.If the strength of the two sides of the car body structure in the lateral direction is asymmetrical,the deformation on the weaker side will be larger,and the end of the car body will begin to deflect under the action of the coupler force,which in turn causes the train to undergo sawtooth buckling.展开更多
文摘0引言高密度互连(high density interconnector,HDI)板出现至今已30多年,在此期间HDI板市场不断扩大,技术也不断提升。HDI板制造工艺技术种类繁多,部分因不合时宜而被淘汰了,部分得到培育而成熟延续了。因此,了解一些HDI板制造技术演变知识,会对掌握HDI板技术有所启示与帮助。
基金This manuscript is supported by the National Key Research and Development Program of China(Grant No.2021YFB2601000)the National Natural Science Foundation of China(Grant Nos.52278437,52008044)+2 种基金the Natural Science Foundation of Hunan Province(Grant No.2022JJ40479)the Science and Technology Innovation Program of Hunan Provincial Department of Transportation(Grant No.202236)the Changsha Outstanding Innovative Youth Training Program Project(Grant No.kq2306009).
文摘Rigid-flexible composite pavement has gained significant popularity in recent decades.This paper provides a comprehensive review of the research progress concerning rigid-flexible composite pavement,aiming to promote its application and address key issues while identifying future directions.The design theory and methodology of rigid-flexible composite pavement are discussed,followed by a description of its structural and mechanical behavior characteristics.The load stress,temperature stress,and their interactive effects between the asphalt layer and the rigid base were analyzed.It is clarified that the asphalt layer serves a dual role as both a“functional layer”and a“structural layer”.Typical distresses of rigid-flexible composite pavement,which primarily occur in the asphalt layer,were discussed.These distresses include reflective cracking,top-down cracking,rutting,and compressive-shear failure.Generally,the integrity of the rigid base and the interlaminar bonding conditions significantly impact the performance and distress of the asphalt layer.The technology for enhancing the performance of rigid-flexible composite pavement is summarized in three aspects:asphalt layer properties,rigid base integrity,and interlaminar bonding condition.The study concludes that developing high-performance pavement materials based on their structural behaviors is an effective approach to improve the performance and durability of rigid-flexible composite pavement.The integrated design of structure and materials represents the future direction of road design.
文摘盲孔在承接AI(Artificial Intelligence)服务器产品用高密度互连(High Density Interconnector,HDI)印制板层与层之间的导通上起到关键性作用。相比其他消费电子类HDI,AI服务器产品用HDI的盲孔具有高厚径比、孔径极差小、玻纤突出短等特点及特殊要求,为盲孔制程管控和CO_(2)激光加工技术带来更高挑战。本文围绕直径100~127μm的盲孔,研究了HDI盲孔前处理过程铜厚波动对孔径影响,分析了CO_(2)激光参数在加工不同孔径时的影响规律。最终提出了盲孔前处理过程铜厚管控标准,获得了典型盲孔孔径和介厚的最优激光参数,从而实现HDI盲孔高质量、高可靠性加工。
基金supported by the National Natural Science Foundation of China (Grant No. 22109008)。
文摘Artificial solid electrolyte interphase(SEI) is promising to inhibit uncontrollable lithium dendrites and enable long cycling stability for lithium metal batteries. However, the essential mechanical stability is limited since organic layers generally have low modulus whereas intrinsic brittleness for inorganic ones remains a great concern. Polymer-based SEIs with rigid and flexible chains in adequate mechanical properties are supposed to address this issue. Herein, a homogeneous and mechanically stable diffusion layer is achieved by blending rigid chains of polyphenylene sulfone(PPSU) with flexible chains of poly(vinylidene fluoride)(PVDF) in a hybrid membrane, enabling uniform diffusion and stabilizing the lithium metal anode. The Li||Cu cell with the protected electrode exhibits a long lifetime more than 450 cycles(0.5 m A cm^(-2), 1.0 m A h cm^(-2))(fourfold longer than the control group) with higher average Coulombic efficiency of 98.7%. Enhanced performances are also observed at Li||Li and full cell configurations. The improved performances are attributed to the controlled morphology and stable interphase, according to scanning electron microscopy(SEM) and electrochemical impedance. This research advances the idea of uniform lithium plating and provides a new insight on how to create a homogeneous and mechanically stable diffusion layer using rigid-flexible polymers.
基金This work was supported by the National Natural Science Foundation of China(No.52172409)Sichuan Outstanding Youth Fund(No.2022JDJQ0025).
文摘Rail vehicles generate huge longitudinal impact loads in collisions.If unreasonable matching exists between the compressive strength of the intermediate coupler and the structural strength of the car body,the risk of car body structure damage and train derailment will increase.Herein,a four-stage rigid-flexible coupling finite element model of the coupler is established considering the coupler buckling load.The influence of the coupler buckling load on the train longitudinal-vertical-hori-zontal buckling behavior was studied,and the mechanism of the train horizontal buckling instability in train collisions was revealed.Analysis results show that an intermediate coupler should be designed to ensure that the actual buckling load is less than the compressive load when the car body structure begins to deform plastically.The actual buckling load of the coupler and the asymmetry of the structural strength of the car body in the lateral direction are two important influencing factors for the lateral buckling of a train collision.If the strength of the two sides of the car body structure in the lateral direction is asymmetrical,the deformation on the weaker side will be larger,and the end of the car body will begin to deflect under the action of the coupler force,which in turn causes the train to undergo sawtooth buckling.
