Lizards are one of the most primitive reptiles in existence,with special limb structures that enable them to move quickly across diverse and complex terrains such as rock piles,shallow shoals,and deserts.A thorough ex...Lizards are one of the most primitive reptiles in existence,with special limb structures that enable them to move quickly across diverse and complex terrains such as rock piles,shallow shoals,and deserts.A thorough exploration was conducted on the biomimetic mechanism and ground-touching mechanism of lizard limbs from both micro and macro perspectives.Inspired by the intricate torso and limb configurations of lizards,a novel Torso-leg-foot biomimetic robot has been conceptualized based on the design of the Big-Foot robot.This robot integrates a Torso-leg-foot system,featuring a parallel torso biomimetic structure with a 2-SPR/UPU/UPR(P)configuration.It utilizes the theory of finite screws to articulate the instantaneous movements of the parallel torso,and the inverse kinematics of this mechanism have been calculated.The reachable workspace of the 2-SPR/UPU/UPR parallel mechanism using FIS theory,which is closely related to the climbing height of the robot.A comprehensive dimension synthesis was conducted on the leg-foot system,and the adoption of the three-pair rod drive method was determined by investigating its Variable Rotating Velocity Characteristics(VRVC).Simulation tests have shown that with an integrated torso,the robot can climb vertical obstacles up to 600 mm in height.The experimental tests of climbing steps and slopes using physical prototypes have confirmed the robot's obstacle-crossing capability.The potential applications of this Torso-leg-foot biomimetic robot is to carry heavy objects across obstacles to perform tasks such as planetary exploration and disaster relief.展开更多
Excited-state intramolecular proton-transfer(ESIPT)based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity,a large Stokes shift,and potential for ratiom...Excited-state intramolecular proton-transfer(ESIPT)based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity,a large Stokes shift,and potential for ratiometric sensing.In general,ESIPT-based fluorophore incorporates an intramolecular hydrogen bonding interaction between a hydrogen bond donor(-OH and NH_(2)are common)and a hydrogen bond acceptor(C=N and C=O).More,protection-deprotection of hydroxyl group as hydrogen bond donor could induce an off-on switch of ESIPT-based emission.Therefore,protection-deprotection of hydroxyl group has been the widely used strategy to design fluorescent probes,where the potential key issue is selecting a protective group that can specifically leave in the presence of the target analyte.In this review,we mainly summarize the specific protecting groups(sites)and deprotection mechanisms for biologically important species(including reactive sulfur species(RSS),reactive oxygen species(ROS),enzymes,etc.),and analyze the advantages and disadvantages of different protection mechanisms from some aspects including probe stability,selectivity,response rate and assay system,etc.Based on the aforementioned,we further point out the current challenges and the potential future direction for developing ESIPT-based probes.展开更多
Heavy ion beams with high linear energy transfer exhibit more beneifcial physical and biological performance than conventional X-rays, thus improving the potential of this type of radiotherapy in the treatment of canc...Heavy ion beams with high linear energy transfer exhibit more beneifcial physical and biological performance than conventional X-rays, thus improving the potential of this type of radiotherapy in the treatment of cancer. However, these two radiotherapy modalities both cause inevitable brain injury. The objective of this study was to evaluate the effects of heavy ion and X-ray irra-diation on the cytoskeleton and cytomechanical properties of rat cortical neurons, as well as to determine the potential mechanism of neuronal injury after irradiation. Cortical neurons from 30 new-born mice were irradiated with heavy ion beams at a single dose of 2 Gy and X-rays at a single dose of 4 Gy;subsequent evaluation of their effects were carried out at 24 hours after irradiation. An immunolfuorescence assay showed that after irradiation with both the heavy ion beam and X-rays, the number of primary neurons was signiifcantly decreased, and there was ev-idence of apoptosis. Radiation-induced neuronal injury was more apparent after X-irradiation. Under atomic force microscopy, the neuronal membrane appeared rough and neuronal rigidity had increased. These cell changes were more apparent following exposure to X-rays. Our ifnd-ings indicated that damage caused by heavy ion and X-ray irradiation resulted in the structural distortion and rearrangement of the cytoskeleton, and affected the cytomechanical properties of the cortical neurons. Moreover, this radiation injury to normal neurons was much severer after irradiation with X-rays than after heavy ion beam irradiation.展开更多
The identification and clarification of active sites of MoS_(2)have long been the focus of research efforts in hydrogen evolution reaction(HER).In this study,we constructed phase transition-induced 1T-2H MoS_(2)hetero...The identification and clarification of active sites of MoS_(2)have long been the focus of research efforts in hydrogen evolution reaction(HER).In this study,we constructed phase transition-induced 1T-2H MoS_(2)heterojunction via lithium intercalation and evaluated the HER activity using on-chip electrocatalytic microdevices(OCEMs).The heterojunction achieved an overpotential of only 226 mV at a cathodic current density of 10 mA/cm^(2),outperforming the basal planes of 1T and 2H MoS_(2).Furthermore,density functional theory(DFT)calculations demonstrated that the charge redistribution occurs at the 1T-2H MoS_(2)interface with electrons transferring from 1T to 2H MoS_(2),and the interfacial S atom at the top site of 1T MoS_(2)presents the smallest overpotential of 0.37 V.Moreover,the interference from highly active edge sites was avoided by precisely exposing specific active areas,quantitatively revealing the catalytic activity order of different types of in-plane MoS_(2)active sites.This work enables a systematic investigation of the HER activity of various active sites in MoS_(2),laying the foundation for quantitative analysis of activity in other lowdimensional materials.展开更多
Friction phenomena are strongly affected by interfacial mechanical and tribochemical effects,which involve major factors such as loads,sliding rates,sliding times,humidity,temperatures,and oxide films.For practical ap...Friction phenomena are strongly affected by interfacial mechanical and tribochemical effects,which involve major factors such as loads,sliding rates,sliding times,humidity,temperatures,and oxide films.For practical applications at different vacuum levels,friction mechanisms(adhesive wear,abrasive wear,fatigue wear,corrosive wear,and micromotor wear)are highly important for the development of advanced materials with desirable tribological properties to promote vacuum tribology.In this review,in combination with the current understanding of friction‒wear interactions,the tribological phenomena caused by changes in the surfaces of friction pairs that are highly dependent on complex conditions in different vacuum environments are analyzed and summarized.Subsequently,protection strategies for different structural materials are summarized.Finally,this work provides an outlook for designing advanced and sustainable protective materials under different vacuum conditions.展开更多
Transition metal dichalcogenides(TMDs)with unique electronic features have attracted tremendous attention in the catalysis and electrochemical sensing area.Decreasing the size and dimension from two-dimensional layere...Transition metal dichalcogenides(TMDs)with unique electronic features have attracted tremendous attention in the catalysis and electrochemical sensing area.Decreasing the size and dimension from two-dimensional layered structures to zero-dimensional ultrasmall nanoparticles with quantum confinement and edge effects generates a larger specific surface area and plentiful active sites.However,the inherently layered structure challenges the synthesis of ultrasmall nanoparticles of MoTe_(2).Herein,in situ polymerization confined Mo atoms have been first immobilized onto N-doped carbon,the reaction of which with Te results in the for-mation of ultrasmall MoTe_(2)nanoparticles.The as-obtained N-doped carbon-supported molybdenum ditellur-ide(MoTe_(2)/NC)exhibited excellent sensitivity towards the electrochemical detection of dopamine ranging from 100 nM to 50μM with a very low detection limit of 7.8 nM(S/N=3).Simultaneously,it also possessed robust stability and selectivity toward detecting dopamine.This study offers a new strategy for the achievement of monodisperse ultrasmall MoTe_(2)nanoparticles,which may be extended to the synthesis of other metal dichalcogenides for various applications in the fields of catalysis and sensing.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52205007).
文摘Lizards are one of the most primitive reptiles in existence,with special limb structures that enable them to move quickly across diverse and complex terrains such as rock piles,shallow shoals,and deserts.A thorough exploration was conducted on the biomimetic mechanism and ground-touching mechanism of lizard limbs from both micro and macro perspectives.Inspired by the intricate torso and limb configurations of lizards,a novel Torso-leg-foot biomimetic robot has been conceptualized based on the design of the Big-Foot robot.This robot integrates a Torso-leg-foot system,featuring a parallel torso biomimetic structure with a 2-SPR/UPU/UPR(P)configuration.It utilizes the theory of finite screws to articulate the instantaneous movements of the parallel torso,and the inverse kinematics of this mechanism have been calculated.The reachable workspace of the 2-SPR/UPU/UPR parallel mechanism using FIS theory,which is closely related to the climbing height of the robot.A comprehensive dimension synthesis was conducted on the leg-foot system,and the adoption of the three-pair rod drive method was determined by investigating its Variable Rotating Velocity Characteristics(VRVC).Simulation tests have shown that with an integrated torso,the robot can climb vertical obstacles up to 600 mm in height.The experimental tests of climbing steps and slopes using physical prototypes have confirmed the robot's obstacle-crossing capability.The potential applications of this Torso-leg-foot biomimetic robot is to carry heavy objects across obstacles to perform tasks such as planetary exploration and disaster relief.
基金National Natural Science Foundation of China(Nos.22277104,22325703,22074084)the Natural Science Foundation of Shanxi Province(No.202203021212184)+3 种基金Research Project supported by Shanxi Scholarship Council of China(No.2022-002)the Basic Research Program of Shanxi Province(Free Exploration)(No.202203021221009)2022 Lvliang City science and technology plan project(Nos.2022SHFZ51,2022GXYF15)Scientific Instrument Center of Shanxi University(No.201512)。
文摘Excited-state intramolecular proton-transfer(ESIPT)based fluorescence probes are particularly attractive due to their unique properties including environmental sensitivity,a large Stokes shift,and potential for ratiometric sensing.In general,ESIPT-based fluorophore incorporates an intramolecular hydrogen bonding interaction between a hydrogen bond donor(-OH and NH_(2)are common)and a hydrogen bond acceptor(C=N and C=O).More,protection-deprotection of hydroxyl group as hydrogen bond donor could induce an off-on switch of ESIPT-based emission.Therefore,protection-deprotection of hydroxyl group has been the widely used strategy to design fluorescent probes,where the potential key issue is selecting a protective group that can specifically leave in the presence of the target analyte.In this review,we mainly summarize the specific protecting groups(sites)and deprotection mechanisms for biologically important species(including reactive sulfur species(RSS),reactive oxygen species(ROS),enzymes,etc.),and analyze the advantages and disadvantages of different protection mechanisms from some aspects including probe stability,selectivity,response rate and assay system,etc.Based on the aforementioned,we further point out the current challenges and the potential future direction for developing ESIPT-based probes.
文摘Heavy ion beams with high linear energy transfer exhibit more beneifcial physical and biological performance than conventional X-rays, thus improving the potential of this type of radiotherapy in the treatment of cancer. However, these two radiotherapy modalities both cause inevitable brain injury. The objective of this study was to evaluate the effects of heavy ion and X-ray irra-diation on the cytoskeleton and cytomechanical properties of rat cortical neurons, as well as to determine the potential mechanism of neuronal injury after irradiation. Cortical neurons from 30 new-born mice were irradiated with heavy ion beams at a single dose of 2 Gy and X-rays at a single dose of 4 Gy;subsequent evaluation of their effects were carried out at 24 hours after irradiation. An immunolfuorescence assay showed that after irradiation with both the heavy ion beam and X-rays, the number of primary neurons was signiifcantly decreased, and there was ev-idence of apoptosis. Radiation-induced neuronal injury was more apparent after X-irradiation. Under atomic force microscopy, the neuronal membrane appeared rough and neuronal rigidity had increased. These cell changes were more apparent following exposure to X-rays. Our ifnd-ings indicated that damage caused by heavy ion and X-ray irradiation resulted in the structural distortion and rearrangement of the cytoskeleton, and affected the cytomechanical properties of the cortical neurons. Moreover, this radiation injury to normal neurons was much severer after irradiation with X-rays than after heavy ion beam irradiation.
基金support from the National Key R&D Program of China(Nos.2021YFA1202802,2022YFF0712200,and 2022YFE0127400)the National Natural Science Foundation of China(No.22409037)+1 种基金the Young Elite Scientists Sponsorship Program by BAST(No.BYESS2023410)the CAS Pioneer Hundred Talents Program.
文摘The identification and clarification of active sites of MoS_(2)have long been the focus of research efforts in hydrogen evolution reaction(HER).In this study,we constructed phase transition-induced 1T-2H MoS_(2)heterojunction via lithium intercalation and evaluated the HER activity using on-chip electrocatalytic microdevices(OCEMs).The heterojunction achieved an overpotential of only 226 mV at a cathodic current density of 10 mA/cm^(2),outperforming the basal planes of 1T and 2H MoS_(2).Furthermore,density functional theory(DFT)calculations demonstrated that the charge redistribution occurs at the 1T-2H MoS_(2)interface with electrons transferring from 1T to 2H MoS_(2),and the interfacial S atom at the top site of 1T MoS_(2)presents the smallest overpotential of 0.37 V.Moreover,the interference from highly active edge sites was avoided by precisely exposing specific active areas,quantitatively revealing the catalytic activity order of different types of in-plane MoS_(2)active sites.This work enables a systematic investigation of the HER activity of various active sites in MoS_(2),laying the foundation for quantitative analysis of activity in other lowdimensional materials.
基金supported by the National Natural Science Foundation of China(No.52275188)the Open Research Fund of the State Key Laboratory of Solid Lubrication(LSL-2309).
文摘Friction phenomena are strongly affected by interfacial mechanical and tribochemical effects,which involve major factors such as loads,sliding rates,sliding times,humidity,temperatures,and oxide films.For practical applications at different vacuum levels,friction mechanisms(adhesive wear,abrasive wear,fatigue wear,corrosive wear,and micromotor wear)are highly important for the development of advanced materials with desirable tribological properties to promote vacuum tribology.In this review,in combination with the current understanding of friction‒wear interactions,the tribological phenomena caused by changes in the surfaces of friction pairs that are highly dependent on complex conditions in different vacuum environments are analyzed and summarized.Subsequently,protection strategies for different structural materials are summarized.Finally,this work provides an outlook for designing advanced and sustainable protective materials under different vacuum conditions.
基金supported by the National Natural Science Foundation of China(No.21771137)the Training Project of Innovation Team of Colleges and Universities in Tianjin(No.TD13-5020)the Natural Science Foundation of the Tianjin City of China(No.18JCJQJC47700).
文摘Transition metal dichalcogenides(TMDs)with unique electronic features have attracted tremendous attention in the catalysis and electrochemical sensing area.Decreasing the size and dimension from two-dimensional layered structures to zero-dimensional ultrasmall nanoparticles with quantum confinement and edge effects generates a larger specific surface area and plentiful active sites.However,the inherently layered structure challenges the synthesis of ultrasmall nanoparticles of MoTe_(2).Herein,in situ polymerization confined Mo atoms have been first immobilized onto N-doped carbon,the reaction of which with Te results in the for-mation of ultrasmall MoTe_(2)nanoparticles.The as-obtained N-doped carbon-supported molybdenum ditellur-ide(MoTe_(2)/NC)exhibited excellent sensitivity towards the electrochemical detection of dopamine ranging from 100 nM to 50μM with a very low detection limit of 7.8 nM(S/N=3).Simultaneously,it also possessed robust stability and selectivity toward detecting dopamine.This study offers a new strategy for the achievement of monodisperse ultrasmall MoTe_(2)nanoparticles,which may be extended to the synthesis of other metal dichalcogenides for various applications in the fields of catalysis and sensing.
