A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580...A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580 to 640℃.X-ray computed tomography was used to visualize pores,and crystal plasticity finite element simulation was adopted for deformation analysis.The microstructure characterizations reveal a hierarchical cell feature composed of α-Mg and eutectic phases.With the increase of injection temperature,large cell content in the material decreases,while the strength of the alloy increases.The underlying mechanism about strength change is that coarse-grained solids experience smaller stress even in hard orientations.The sample fabricated at a moderate temperature of 620℃ exhibits the highest elongation,least quantity and lower local concentration of pores.The detachment and tearing cracks formed at lower injection temperature and defect bands formed at higher injection temperature add additional crack sources and deteriorate the ductility of the materials.展开更多
Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and hi...Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.展开更多
随着摩尔定律指引下的晶体管微缩逼近物理极限,先进封装技术通过系统微型化与异构集成,成为突破芯片性能瓶颈的关键路径。作为先进封装的核心分支,2.5D封装通过硅/玻璃中介层实现高密度互连与多芯片异构集成,兼具高带宽、低延迟和小型...随着摩尔定律指引下的晶体管微缩逼近物理极限,先进封装技术通过系统微型化与异构集成,成为突破芯片性能瓶颈的关键路径。作为先进封装的核心分支,2.5D封装通过硅/玻璃中介层实现高密度互连与多芯片异构集成,兼具高带宽、低延迟和小型化优势,广泛应用于人工智能、高性能计算及移动电子领域。系统阐述了2.5D封装的核心结构(如Co Wo S、EMIB和I-Cube)及其技术特征,重点剖析了Chiplet模块化设计、硅通孔(TSV)工艺优化、微凸点可靠性提升、铜-铜直接键合界面工程以及再布线层多物理场协同设计等关键技术的最新进展。未来研究需聚焦低成本玻璃基板、原子层沉积技术抑制界面氧化以及多物理场协同设计等方面,以突破良率和散热瓶颈,推动2.5D封装在后摩尔时代高算力场景中的广泛应用。展开更多
Incorporating organic bulky cations in the precursor or post-treatment to achieve two-dimensional/thr ee-dimensional(2D/3D)heterojunction is an effective strategy for enhancing the stability of perovskite materials.Ho...Incorporating organic bulky cations in the precursor or post-treatment to achieve two-dimensional/thr ee-dimensional(2D/3D)heterojunction is an effective strategy for enhancing the stability of perovskite materials.However,the issue of insufficient charge transport in 2D perovskites limits their development,and the fundamental mechanism of out-of-plane carrier transport remains unclear.This study designed and synthesized seven organic phenyl-core cations,differentiated at the 1-and 1,4-positions,and identified the impacts on the corresponding properties of the 2D crystalline perovskite.Shorter cations facilitated a more compact arrangement of adjacent inorganic layers,aligning to favor charge transport along the vertical direction.In addition,introducing high electronegativity led to increased intermolecular interactions,resulting in enhanced structural stability and improved phenyl ring π-orbital overlap and interlayer electron coupling,yielding efficient charge transport.Resilience to thermal stressing of the perovskite was strongly correlated with the carbon chain length of the spacer cations.The increase in cation length and the reduction in the rigidity of the amino-terminal both aided in the dispersion of thermal stress in the inorganic framework.Additional hydrogen bonding also contributed to mitigating structural disorder.展开更多
Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurr...Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurrence of earthquakes in subduction zones is thought to be closely related to the thermal structure of the incoming plate. However, in the case of the subducting Nazca Plate beneath the Colombia–Ecuador zone, the thermal structure remains unclear, especially its hydraulic distribution. On the basis of 3D thermal models, we present new insights into the plate interface conditions of Colombia–Ecuador interplate and megathrust earthquakes. We show that the plate geometry strongly affects the along-strike thermal structure of the slab beneath Colombia and Ecuador, with the subduction of the Carnegie Ridge playing an important role. Our results further reveal that the unique geometry of the Nazca Plate is the primary reason for the relatively high temperatures of the slab beneath Colombia. We suggest that the positions of the100–200 ℃ and 350–450 ℃ isotherms on the plate interface determine the updip and downdip limits of the seismogenic zone. For Colombia–Ecuador interplate earthquakes, the released fluids control the distribution of shallow-depth earthquakes, whereas the age and geometry of the slab control the distribution of intermediate-depth earthquakes. The average temperature of the plate interface at the upper limit of large megathrust earthquakes is hotter than previously thought, which is more consistent with our understanding of the Colombia–Ecuador subduction zone. We predict that the potential location of future large seismic events could be in the rupture zone of past seismic events or offshore of northern Colombia.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51825101,52001202)the National Key Research and Development Program of China(No.2021YFA1600900)。
文摘A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580 to 640℃.X-ray computed tomography was used to visualize pores,and crystal plasticity finite element simulation was adopted for deformation analysis.The microstructure characterizations reveal a hierarchical cell feature composed of α-Mg and eutectic phases.With the increase of injection temperature,large cell content in the material decreases,while the strength of the alloy increases.The underlying mechanism about strength change is that coarse-grained solids experience smaller stress even in hard orientations.The sample fabricated at a moderate temperature of 620℃ exhibits the highest elongation,least quantity and lower local concentration of pores.The detachment and tearing cracks formed at lower injection temperature and defect bands formed at higher injection temperature add additional crack sources and deteriorate the ductility of the materials.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(T2121004)Key Programme(52235007)National Outstanding Youth Foundation of China(52325504).
文摘Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.
文摘随着摩尔定律指引下的晶体管微缩逼近物理极限,先进封装技术通过系统微型化与异构集成,成为突破芯片性能瓶颈的关键路径。作为先进封装的核心分支,2.5D封装通过硅/玻璃中介层实现高密度互连与多芯片异构集成,兼具高带宽、低延迟和小型化优势,广泛应用于人工智能、高性能计算及移动电子领域。系统阐述了2.5D封装的核心结构(如Co Wo S、EMIB和I-Cube)及其技术特征,重点剖析了Chiplet模块化设计、硅通孔(TSV)工艺优化、微凸点可靠性提升、铜-铜直接键合界面工程以及再布线层多物理场协同设计等关键技术的最新进展。未来研究需聚焦低成本玻璃基板、原子层沉积技术抑制界面氧化以及多物理场协同设计等方面,以突破良率和散热瓶颈,推动2.5D封装在后摩尔时代高算力场景中的广泛应用。
基金financially supported by the Key Fund Project of Tianjin Natural Science Foundation(24JCZDJC00510)the Fundamental Research Funds for the Central Universitiespartially supported by the U.S.Department of Energy under Contract No.DE-AC3608GO28308 with Alliance for Sustainable Energy,Limited Liability Company(LLC),the Manager and Operator of the National Renewable Energy Laboratory,through Grant No.DE-SC0020718。
文摘Incorporating organic bulky cations in the precursor or post-treatment to achieve two-dimensional/thr ee-dimensional(2D/3D)heterojunction is an effective strategy for enhancing the stability of perovskite materials.However,the issue of insufficient charge transport in 2D perovskites limits their development,and the fundamental mechanism of out-of-plane carrier transport remains unclear.This study designed and synthesized seven organic phenyl-core cations,differentiated at the 1-and 1,4-positions,and identified the impacts on the corresponding properties of the 2D crystalline perovskite.Shorter cations facilitated a more compact arrangement of adjacent inorganic layers,aligning to favor charge transport along the vertical direction.In addition,introducing high electronegativity led to increased intermolecular interactions,resulting in enhanced structural stability and improved phenyl ring π-orbital overlap and interlayer electron coupling,yielding efficient charge transport.Resilience to thermal stressing of the perovskite was strongly correlated with the carbon chain length of the spacer cations.The increase in cation length and the reduction in the rigidity of the amino-terminal both aided in the dispersion of thermal stress in the inorganic framework.Additional hydrogen bonding also contributed to mitigating structural disorder.
基金benefited from the financial support of the CAS Pioneer Hundred Talents Program and the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0708)。
文摘Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurrence of earthquakes in subduction zones is thought to be closely related to the thermal structure of the incoming plate. However, in the case of the subducting Nazca Plate beneath the Colombia–Ecuador zone, the thermal structure remains unclear, especially its hydraulic distribution. On the basis of 3D thermal models, we present new insights into the plate interface conditions of Colombia–Ecuador interplate and megathrust earthquakes. We show that the plate geometry strongly affects the along-strike thermal structure of the slab beneath Colombia and Ecuador, with the subduction of the Carnegie Ridge playing an important role. Our results further reveal that the unique geometry of the Nazca Plate is the primary reason for the relatively high temperatures of the slab beneath Colombia. We suggest that the positions of the100–200 ℃ and 350–450 ℃ isotherms on the plate interface determine the updip and downdip limits of the seismogenic zone. For Colombia–Ecuador interplate earthquakes, the released fluids control the distribution of shallow-depth earthquakes, whereas the age and geometry of the slab control the distribution of intermediate-depth earthquakes. The average temperature of the plate interface at the upper limit of large megathrust earthquakes is hotter than previously thought, which is more consistent with our understanding of the Colombia–Ecuador subduction zone. We predict that the potential location of future large seismic events could be in the rupture zone of past seismic events or offshore of northern Colombia.
