To improve the adaptability of TBMs in diverse geological environments,this paper proposes a reconfigurable Type-V thrust mechanism(V-TM)with rearrangeable working states,in which structural stiffness can be automatic...To improve the adaptability of TBMs in diverse geological environments,this paper proposes a reconfigurable Type-V thrust mechanism(V-TM)with rearrangeable working states,in which structural stiffness can be automatically altered during operation.Therefore,millions of configurations can be obtained,and thousands of instances of working status per configuration can be set respectively.Nonetheless,the complexity of configurations and diversity of working states contributes to further complications for the structural stiffness algorithm.This results in challenges such as difficulty calculating the payload compliance index and the environment adaptability index.To solve this problem,we use the configuration matrix to describe the relationship between propelling jacks under reconfiguration and adopt pattern vectors to describe the working state of each hydraulic cylinder.Then,both the dynamic compatible equation between propeller forces of the hydraulic cylinders and driving forces,and the kinematic harmonizing equation between the hydraulic cylinder displacements and their deformations are established.Next,we derive the stiffness analytical equation using Hooke’s law and the Jacobian Matrix.The proposed approach provides an effective algorithm to support structural rigidity analysis,and lays a solid theoretical foundation for calculating the performance indexes of the V-TM.We then analyze the rigidity characteristics of typical configurations under different working states,and obtain the main factors affecting structural stiffness of the V-TM.The results show the deviation degree of structural parameters in hydraulic cylinders within the same group,and the working status of propelling jacks.Finally,our constructive conclusions contribute valuable information for matching and optimization by drawing on the factors that affect the structural rigidity of the V-TM.展开更多
The bulk photovoltaic(BPV)effect,which generates steady photocurrents and above-bandgap photovoltages in non-centrosymmetric materials when exposed to light,holds great potential for advancing optoelectronic and photo...The bulk photovoltaic(BPV)effect,which generates steady photocurrents and above-bandgap photovoltages in non-centrosymmetric materials when exposed to light,holds great potential for advancing optoelectronic and photovoltaic technologies.However,its influence on the reconfiguration of ferroelectric domain structure remains underexplored.In this study,we developed a phase-field model to understand the BPV effect in ferroelectric oxides.Our model reveals that variations in BPV currents across domains create opposing charges at domain walls,enhancing the electric field within domains to~1000 kV/cm.The strong electric fields can reorient the ferroelectric polarization and enable ultrafast domain wall movements and nonvolatile domain switching on the picosecond scale.Applying anisotropic strain can further strengthen this effect,enablingmore precise control of domain switching.Our findings advance the fundamental understanding of BPV effect in ferroelectrics,paving the ways for developing opto-ferroelectric memory technologies and highefficiency photovoltaic applications via precise domain engineering.展开更多
Addressing peripheral nerve defects remains a significant challenge in regenerative neurobiology.Autograftsemerged as the gold-standard management,however,are hindered by limited availability and potential neuromaform...Addressing peripheral nerve defects remains a significant challenge in regenerative neurobiology.Autograftsemerged as the gold-standard management,however,are hindered by limited availability and potential neuromaformation.Numerous recent studies report the potential of wireless electronic system for nerve defects repair.Unfortunately,few has met clinical needs for inadequate electrode precision,poor nerve entrapment andinsufficient bioactivity of the matrix material.Herein,we present an advanced wireless electrical nerve stimulator,based on water-responsive self-curling silk membrane with excellent bioabsorbable and biocompatibleproperties.We constructed a unique bilayer structure with an oriented pre-stretched inner layer and a generalsilk membrane as outer layer.After wetting,the simultaneous contraction of inner layer and expansion of outerlayer achieved controllable super-contraction from 2D flat surface to 3D structural reconfiguration.It enablesshape-adaptive wrapping to cover around nerves,overcomes the technical obstacle of preparing electrodes on theinner wall of the conduit,and prevents electrode breakage caused by material expansion in water.The use of forkcapacitor-like metal interface increases the contact points between the metal and the regenerating nerve,solvingthe challenge of inefficient and rough electrical stimulation methods in the past.Newly developed electronicstimulator is effective in restoring 10 mm rat sciatic nerve defects comparable to autologous grafts.The underlyingmechanism involves that electric stimulation enhances anterograde mitochondrial transport to matchenergy demands.This newly introduced device thereby demonstrated the potential as a viable and efficaciousalternative to autografts for enhancing peripheral nerve repair and functional recovery.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51675180)National Key Basic Research Program of China(973 Program,Grant No.2013CB037503)
文摘To improve the adaptability of TBMs in diverse geological environments,this paper proposes a reconfigurable Type-V thrust mechanism(V-TM)with rearrangeable working states,in which structural stiffness can be automatically altered during operation.Therefore,millions of configurations can be obtained,and thousands of instances of working status per configuration can be set respectively.Nonetheless,the complexity of configurations and diversity of working states contributes to further complications for the structural stiffness algorithm.This results in challenges such as difficulty calculating the payload compliance index and the environment adaptability index.To solve this problem,we use the configuration matrix to describe the relationship between propelling jacks under reconfiguration and adopt pattern vectors to describe the working state of each hydraulic cylinder.Then,both the dynamic compatible equation between propeller forces of the hydraulic cylinders and driving forces,and the kinematic harmonizing equation between the hydraulic cylinder displacements and their deformations are established.Next,we derive the stiffness analytical equation using Hooke’s law and the Jacobian Matrix.The proposed approach provides an effective algorithm to support structural rigidity analysis,and lays a solid theoretical foundation for calculating the performance indexes of the V-TM.We then analyze the rigidity characteristics of typical configurations under different working states,and obtain the main factors affecting structural stiffness of the V-TM.The results show the deviation degree of structural parameters in hydraulic cylinders within the same group,and the working status of propelling jacks.Finally,our constructive conclusions contribute valuable information for matching and optimization by drawing on the factors that affect the structural rigidity of the V-TM.
基金the support of the National Science Foundation via grant CMMI-2132105.
文摘The bulk photovoltaic(BPV)effect,which generates steady photocurrents and above-bandgap photovoltages in non-centrosymmetric materials when exposed to light,holds great potential for advancing optoelectronic and photovoltaic technologies.However,its influence on the reconfiguration of ferroelectric domain structure remains underexplored.In this study,we developed a phase-field model to understand the BPV effect in ferroelectric oxides.Our model reveals that variations in BPV currents across domains create opposing charges at domain walls,enhancing the electric field within domains to~1000 kV/cm.The strong electric fields can reorient the ferroelectric polarization and enable ultrafast domain wall movements and nonvolatile domain switching on the picosecond scale.Applying anisotropic strain can further strengthen this effect,enablingmore precise control of domain switching.Our findings advance the fundamental understanding of BPV effect in ferroelectrics,paving the ways for developing opto-ferroelectric memory technologies and highefficiency photovoltaic applications via precise domain engineering.
基金supported by the National Natural Science Foundation of China(82172476,82172393).
文摘Addressing peripheral nerve defects remains a significant challenge in regenerative neurobiology.Autograftsemerged as the gold-standard management,however,are hindered by limited availability and potential neuromaformation.Numerous recent studies report the potential of wireless electronic system for nerve defects repair.Unfortunately,few has met clinical needs for inadequate electrode precision,poor nerve entrapment andinsufficient bioactivity of the matrix material.Herein,we present an advanced wireless electrical nerve stimulator,based on water-responsive self-curling silk membrane with excellent bioabsorbable and biocompatibleproperties.We constructed a unique bilayer structure with an oriented pre-stretched inner layer and a generalsilk membrane as outer layer.After wetting,the simultaneous contraction of inner layer and expansion of outerlayer achieved controllable super-contraction from 2D flat surface to 3D structural reconfiguration.It enablesshape-adaptive wrapping to cover around nerves,overcomes the technical obstacle of preparing electrodes on theinner wall of the conduit,and prevents electrode breakage caused by material expansion in water.The use of forkcapacitor-like metal interface increases the contact points between the metal and the regenerating nerve,solvingthe challenge of inefficient and rough electrical stimulation methods in the past.Newly developed electronicstimulator is effective in restoring 10 mm rat sciatic nerve defects comparable to autologous grafts.The underlyingmechanism involves that electric stimulation enhances anterograde mitochondrial transport to matchenergy demands.This newly introduced device thereby demonstrated the potential as a viable and efficaciousalternative to autografts for enhancing peripheral nerve repair and functional recovery.
