Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials...Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.展开更多
With the assistance of grinding dynamic model,this paper studied she dynamic parameters of single size ball grinding of single grade size material and mixed materials as well as multi-size ball grinding of single-grad...With the assistance of grinding dynamic model,this paper studied she dynamic parameters of single size ball grinding of single grade size material and mixed materials as well as multi-size ball grinding of single-grade material,and analog-calculated the product size distribution of multi-size ball grinding of mixed materials.The study showed:in a certain grinding timet the analog-calculation achieved the same result as the experiment.展开更多
Human long bones exhibit pore size gradients with small pores in the exterior cortical bone and large pores in the interior cancellous bone.However,most current bone tissue engineering(BTE)scaffolds only have homogene...Human long bones exhibit pore size gradients with small pores in the exterior cortical bone and large pores in the interior cancellous bone.However,most current bone tissue engineering(BTE)scaffolds only have homogeneous porous structures that do not resemble the graded architectures of natural bones.Pore-size graded(PSG)scaffolds are attractive for BTE since they can provide biomimicking porous structures that may lead to enhanced bone tissue regeneration.In this study,uniform pore size scaffolds and PSG scaffolds were designed using the gyroid unit of triply periodic minimal surface(TPMS),with small pores(400μm)in the periphery and large pores(400,600,800 or 1000μm)in the center of BTE scaffolds(designated as 400-400,400–600,400–800,and 400–1000 scaffold,respectively).All scaffolds maintained the same porosity of 70 vol%.BTE scaffolds were subsequently fabricated through digital light processing(DLP)3D printing with the use of biphasic calcium phosphate(BCP).The results showed that DLP 3D printing could produce PSG BCP scaffolds with high fidelity.The PSG BCP scaffolds possessed improved biocompatibility and mass transport properties as compared to uniform pore size BCP scaffolds.In particular,the 400–800 PSG scaffolds promoted osteogenesis in vitro and enhanced new bone formation and vascularization in vivo while they displayed favorable compressive properties and permeability.This study has revealed the importance of structural design and optimization of BTE scaffolds for achieving balanced mechanical,mass transport and biological performance for bone regeneration.展开更多
For medium and high permeability oilfields, filling sand control technology is one of the main measures to prevent formation sand production and achieve stable production and increase production.As the largest oil-bea...For medium and high permeability oilfields, filling sand control technology is one of the main measures to prevent formation sand production and achieve stable production and increase production.As the largest oil-bearing block in Qudi oilfield, Qu9 fault block has serious sand production in Guan3 formation, and sand control is required to meet normal production.Through the continuous development and optimization of sand control technology, in recent years, the commonly used sand control technologies in Qudi oilfield include squeeze filling sand control, chemical sand control, cyclic filling and other processes. It is found that the squeeze filling process can better meet the needs of Qu9 Guan3 block.At the same time, Qu9 Guan3 block has problems such as high shale content, strong sensitivity and thick crude oil viscosity. It is necessary to optimize the squeeze filling sand control process, and put forward supporting technologies such as pre reservoir cleaning agent and variable particle size graded sand addition, so as to better transform the formation, improve seepage efficiency and enhance the productivity of single wells while doing a good job in reservoir protection.展开更多
基金supported by the National Key Research and Development Program of China(grant SQ2019YFE012189,grant2017YFB0307001)the National Natural Science Foundation of China(grants 51973093,U1533122,and 51773094)+5 种基金the Natural Science Foundation of Tianjin(grant number 18JCZDJC36800)the National Special Support Plan for High-level Talents people(grant number C041800902)the Science Foundation for Distinguished Young Scholars of Tianjin(grant number 18JCJQJC46600)the Frontiers Science Center for New Organic Matter(Grant Number 63181206)the Fundamental Research Funds for the Central Universities(grant 63171219)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University(grant LK1704)。
文摘Increasing mechanical flexibility without sacrificing electrochemical performance of the electrode material is highly desired in the design of flexible electrochemical energy storage devices.In metal-related materials science,decreasing the grain size introduces more grain boundaries;this stops dislocations and crack propagation under deformation,and results in increased strength and toughness.However,such a size refinement effect has not been considered in the mechanical properties,particle stacking,wetting,and electrochemical performances of flexible supercapacitor electrodes.In this paper,MXene was used as an electrode material to study the size refinement effect of flexible supercapacitors.Size refinement improved the strength and toughness of the MXene electrodes,and this resulted in increased flexibility.Finite elemental analysis provided a theoretical understanding of size refinement-increased flexibility.Moreover,the size refinement also improved the specific surface area,electric conductance,ion transportation,and water wetting properties of the electrode,and the size refinement provided highly increased energy density and power density of the MXene supercapacitors.A highly flexible,water-proof supercapacitor was fabricated using size-refined MXene.The current study provides a new viewpoint for designing tough and flexible energy storage electrodes.The size refinement effect may also be applicable for metal ion batteries and electronic and photo devices composed of MXene and other nanoparticles.
文摘With the assistance of grinding dynamic model,this paper studied she dynamic parameters of single size ball grinding of single grade size material and mixed materials as well as multi-size ball grinding of single-grade material,and analog-calculated the product size distribution of multi-size ball grinding of mixed materials.The study showed:in a certain grinding timet the analog-calculation achieved the same result as the experiment.
基金supported by National Key R&D Program of China[2022YFE0197100]Shenzhen Science and Technology Innovation Commission[KQTD20190929172505711,KQTD20200820113012029]+1 种基金Guangdong Provincial Key Laboratory of Advanced Biomaterials(2022B1212010003)Hong Kong’s Research Grants Council(RGC)through research grants(17200519,17202921,17201622 and N_HKU749/22).
文摘Human long bones exhibit pore size gradients with small pores in the exterior cortical bone and large pores in the interior cancellous bone.However,most current bone tissue engineering(BTE)scaffolds only have homogeneous porous structures that do not resemble the graded architectures of natural bones.Pore-size graded(PSG)scaffolds are attractive for BTE since they can provide biomimicking porous structures that may lead to enhanced bone tissue regeneration.In this study,uniform pore size scaffolds and PSG scaffolds were designed using the gyroid unit of triply periodic minimal surface(TPMS),with small pores(400μm)in the periphery and large pores(400,600,800 or 1000μm)in the center of BTE scaffolds(designated as 400-400,400–600,400–800,and 400–1000 scaffold,respectively).All scaffolds maintained the same porosity of 70 vol%.BTE scaffolds were subsequently fabricated through digital light processing(DLP)3D printing with the use of biphasic calcium phosphate(BCP).The results showed that DLP 3D printing could produce PSG BCP scaffolds with high fidelity.The PSG BCP scaffolds possessed improved biocompatibility and mass transport properties as compared to uniform pore size BCP scaffolds.In particular,the 400–800 PSG scaffolds promoted osteogenesis in vitro and enhanced new bone formation and vascularization in vivo while they displayed favorable compressive properties and permeability.This study has revealed the importance of structural design and optimization of BTE scaffolds for achieving balanced mechanical,mass transport and biological performance for bone regeneration.
文摘For medium and high permeability oilfields, filling sand control technology is one of the main measures to prevent formation sand production and achieve stable production and increase production.As the largest oil-bearing block in Qudi oilfield, Qu9 fault block has serious sand production in Guan3 formation, and sand control is required to meet normal production.Through the continuous development and optimization of sand control technology, in recent years, the commonly used sand control technologies in Qudi oilfield include squeeze filling sand control, chemical sand control, cyclic filling and other processes. It is found that the squeeze filling process can better meet the needs of Qu9 Guan3 block.At the same time, Qu9 Guan3 block has problems such as high shale content, strong sensitivity and thick crude oil viscosity. It is necessary to optimize the squeeze filling sand control process, and put forward supporting technologies such as pre reservoir cleaning agent and variable particle size graded sand addition, so as to better transform the formation, improve seepage efficiency and enhance the productivity of single wells while doing a good job in reservoir protection.
