The postharvest senescence phase of table grapes comprises a series of biological processes.MicroRNAs(miRNAs)regulate downstream genes at the post-transcriptional level;however,whether miRNAs are involved in postharve...The postharvest senescence phase of table grapes comprises a series of biological processes.MicroRNAs(miRNAs)regulate downstream genes at the post-transcriptional level;however,whether miRNAs are involved in postharvest grape senescence remains unclear.We used small RNA sequencing to identify postharvest-related miRNAs in‘Red Globe'(Vitis vinifera)grapes harvested after 0,30,and 60 d of storage at 4℃(RG0,RG30,RG60).In total,42 known and 219 novel miRNA candidates were obtained.During fruit senescence,the expression of PC-3p-3343_1921,mi R2950,miR395k,miR2111,miR159c,miR169q,PC-5p-1112_4500,and miR167b changed signifcantly(P<0.05).Degradation sequencing identifed 218 targets associated with cell wall organization,tricarboxylic acid(TCA)cycling,pathogen defense,carbon metabolism,hormone signaling,the anthocyanin metabolism pathway,and energy regulation,of which ARF6,GRF3,TCP2,CP1,MYBA2,and WRKY72 were closely related to fruit senescence.We also verified that VIT_00s2146g00010,VIT_02s0012g01750,and VIT_03s0038g00160 with unknown functions are cleaved by senescence-related PC-5p-1112_4500 via the dual luciferase assay,and the transient transformation of grape berries showed that they regulate berry senescence.These results deepen our understanding of the role of mi RNAs in regulating grape berry senescence and prolonging the shelf life of horticultural products.Based on these results,we propose a new theoretical strategy for delaying the postharvest senescence of horticultural products by regulating the expression of key miRNAs(e.g.,PC-5p-1112_4500),thereby extending their shelf life.展开更多
Soft robots, inspired by the flexibility and versatility of biological organisms, have potential in a variety of applications. Recent advancements in magneto-soft robots have demonstrated their abilities to achieve pr...Soft robots, inspired by the flexibility and versatility of biological organisms, have potential in a variety of applications. Recent advancements in magneto-soft robots have demonstrated their abilities to achieve precise remote control through magnetic fields, enabling multi-modal locomotion and complex manipulation tasks. Nonetheless, two main hurdles must be overcome to advance the field: developing a multi-component substrate with embedded magnetic particles to ensure the requisite flexibility and responsiveness, and devising a cost-effective,straightforward method to program three-dimensional distributed magnetic domains without complex processing and expensive machinery. Here, we introduce a cost-effective and simple heat-assisted in-situ integrated molding fabrication method for creating magnetically driven soft robots with three-dimensional programmable magnetic domains. By synthesizing a composite material with neodymium-iron-boron(NdFeB) particles embedded in a polydimethylsiloxane(PDMS) and Ecoflex matrix(PDMS:Ecoflex = 1:2 mass ratio, 50% magnetic particle concentration), we achieved an optimized balance of flexibility, strength, and magnetic responsiveness. The proposed heat-assisted in-situ magnetic domains programming technique,performed at an experimentally optimized temperature of 120℃, resulted in a 2 times magnetization strength(9.5 mT) compared to that at 20℃(4.8 m T), reaching a saturation level comparable to a commercial magnetizer. We demonstrated the versatility of our approach through the fabrication of six kinds of robots, including two kinds of two-dimensional patterned soft robots(2D-PSR), a circular six-pole domain distribution magnetic robot(2D-CSPDMR), a quadrupedal walking magnetic soft robot(QWMSR), an object manipulation robot(OMR), and a hollow thin-walled spherical magneto-soft robot(HTWSMSR). The proposed method provides a practical solution to create highly responsive and adaptable magneto-soft robots.展开更多
This paper focuses on the distribution of passenger flow in Huoying Station,Line 13 of Beijing subway system.The transformation measures taken by Line 13 since operation are firstly summarized.Then the authors elabora...This paper focuses on the distribution of passenger flow in Huoying Station,Line 13 of Beijing subway system.The transformation measures taken by Line 13 since operation are firstly summarized.Then the authors elaborate the facilities and equipment of this station,especially the node layout and passenger flow field.An optimization scheme is proposed to rapidly distribute the passenger flow in Huoying Station by adjusting the operation time of the escalator in the direction of Xizhimen.The authors adopt Queuing theory and Anylogic simulation software to simulate the original and the optimized schemes of Huoying Station to distribute the passenger flow.The results of the simulation indicate that the optimized scheme could effectively alleviate the traffic congestion in the hall of Huoying Station,and the pedestrian density in other places of the hall is lowered;passengers could move freely in the hall and no new congestion points would form.The rationality of the scheme is thus proved.展开更多
Tungsten bronze coatings and films have attracted global attention for their applications in near-infrared(NIR)-shielding windows.However,they are unstable in strong ultraviolet,humid heat,alkaline and/or oxidizing en...Tungsten bronze coatings and films have attracted global attention for their applications in near-infrared(NIR)-shielding windows.However,they are unstable in strong ultraviolet,humid heat,alkaline and/or oxidizing environments and are difficult to be coated on glass surfaces with complex shape.Here,we address these limitations by doping sodium tungsten bronze(Na_(x)WO_(3))into bulk glasses using a simple glass melting method.X-ray diffraction,Raman spectroscopy,X-ray photoelectron spectroscopy,TEM and SEM-EDS characterization confirmed the presence of sodium tungsten bronze(Na_(x)WO_(3))functional units inside the 34SiO_(2)-38B_(2)O_(3)-28NaF glass matrix.Because the functional units are well protected by the glass matrix,the fabricated glasses are stable under hot,humid,oxidizing conditions,as well as under ambient conditions,with no change after 360 days.The NIR-shielding performance of these glasses can be adjusted to as high as 100%by varying WO_(x)concentration(2-8 mol%)and quenching temperature(1000-1400℃).With a content of 6 mol%WO_(x)and a quenching temperature of 1000℃,the bulk glass shows 63%transmission of visible light and only 11%transmission of NIR light at 1100 nm.Thermal insulation experiments show that the NIR-shielding performance of the glasses are far superior to commercial soda lime window glass or indium-doped tin oxide(ITO)glass,and comparable to cesium tungsten bronze coated glass.The novel bulk glasses have higher stability,simpler processing,and can be easily made into complex shapes,making them excellent alternative materials for energy-saving glasses.展开更多
In this paper,removal of nitrogen oxide（NO） is investigated in capacitive atmospheric pressure discharges driven by both radio-frequency（RF） and trapezoidal pulsed power with a onedimensional self-consistent fluid...In this paper,removal of nitrogen oxide（NO） is investigated in capacitive atmospheric pressure discharges driven by both radio-frequency（RF） and trapezoidal pulsed power with a onedimensional self-consistent fluid model.The results show that the number density of NO could be reduced significantly once a short pulse of low duty ratio is additionally applied to the RF power.It is found that the process of NO removal by the pulse-modulated RF discharge could be divided into three stages：the quick reaction stage,the NO removal stage,and the sustaining stage.Furthermore,the temporal evolution of particle densities is analyzed,and the key reactions in each stage are discovered.Finally,the influence on the removal efficiency of the voltage amplitude of the pulse and the RF voltage amplitude is investigated.展开更多
The effect of calcination temperature on the pozzolanic activity of maize straw stem ash(MSSA)was evaluated.The MSSA samples calcined at temperature values of 500,700,and 850℃ were dissolved in portlandite solution f...The effect of calcination temperature on the pozzolanic activity of maize straw stem ash(MSSA)was evaluated.The MSSA samples calcined at temperature values of 500,700,and 850℃ were dissolved in portlandite solution for 6 h,thereby obtaining residual samples.The MSSA and MSSA residual samples were analyzed using Fourier transform infrared spectroscopy,X-ray powder diffraction scanning electron microscopy,and X-ray photoelectron spectroscopy to determine vibration bonds,minerals,microstructures,and Si 2p transformation behavior.The conductivity,pH value,and loss of conductivity with dissolving time of the MSSA-portlandite mixed solution were also determined.The main oxide composition of MSSA was silica and potassium oxide.The dissolution of the Si^(4+) content of MSSA at 500℃ was higher than those of the other calcination temperatures.The conductivity and loss of conductivity of MSSA at 700℃ were higher than those of the other calcination temperatures at a particular dissolving time due to the higher KCl content in MSSA at 700℃.C-S-H was easily identified in MSSA samples using X-ray powder diffraction,and small cubic and nearly spherical particles of C-S-H were found in the MSSA residual samples.In conclusion,the optimum calcination temperature of MSSA having the best pozzolanic activity is 500℃,but excessive agglomeration must be prevented.展开更多
This paper reports on the performance evaluation of a novel latching-type electromagnetic actuator which is designed to be embedded at selected joints along single-port laparoscopic surgical instruments (SLS). The aim...This paper reports on the performance evaluation of a novel latching-type electromagnetic actuator which is designed to be embedded at selected joints along single-port laparoscopic surgical instruments (SLS). The aim of this actuator is to allow these instruments to become articulated with a push of a button in order to provide the optimum angulation required during SLS operations. This new actuator is comprised of electromagnetic coil elements, soft magnetic frames and a permanent magnet. Unlike conventional electromagnetic actuators, latching-type electromagnetic actuators could maintain their positions at either end of the actuation stroke without any power application requirement. In the current design, magnetic attraction forces initiated between the permanent magnet and the magnetic frame are utilised to lock the position of the actuator whilst a certain angulation position of the actuator is achieved as a result of the magnetic repulsion forces established between the permanent magnet and the coil elements. The performance of the new actuator in terms of the output force, maximum angulation and patient’s safety, was evaluated experimentally and the results were found to compare well with those acquired numerically using finite element methods. This actuator was seen to exhibit sufficient actuation forces and hence, it was capable of providing adaptable angulation characteristics for SLS tools. Finally, thermal evaluation of the actuator’s operation was conducted, which was found to be within safety limits specified by clinicians.展开更多
The pneumatic gripper in industrial applications has the advantages of structure simplicity and great adaptability,but its gripping power is usually limited due to the low modulus of soft materials.To address this pro...The pneumatic gripper in industrial applications has the advantages of structure simplicity and great adaptability,but its gripping power is usually limited due to the low modulus of soft materials.To address this problem,a novel bionic pneumatic gripper inspired by spider legs is proposed.The design has two pairs of symmetrical fingers,each finger consists of two pneumatic actuated joints,two rigid links and one pneumatic soft pad.The rigid link connects the pneumatic chamber which is enclosed in a retractable shell to increase the actuation pressure and the gripping force.The compressibility and elasticity of the soft joint and pad enable the gripper to grasp fragile objects without damage.The modeling of the bionic gripper is developed,and the parameters of the joint actuators are optimized accordingly.The prototype is manufactured and tested with the developed experimental platform,where the gripping force,flexibility and adaptability are evaluated.The results indicate that the designed gripper can grasp irregular and fragile items in sizes from 40 to 140 mm without damage,and the lifting weight is up to 15 N.展开更多
Silicon carbide(SiC)high-voltage,high-power semiconductor devices are essential for next-generation power systems,yet conventional silicone elastomer encapsulation materials suffer from insulation degradation under ex...Silicon carbide(SiC)high-voltage,high-power semiconductor devices are essential for next-generation power systems,yet conventional silicone elastomer encapsulation materials suffer from insulation degradation under extreme thermal and electrical stresses,highlighting the critical need for novel dielectric materials.This article brings phenyl groups into the side group of conventional silicone elastomers through ring-opening polymerisation and hydrosilylation,developing phenyl-modified silicone elastomers.The material's superior thermal resistance is substantiated through thermal ageing and thermogravimetric analysis.Moreover,this study delineates the insulating robustness of the material by gauging its dielectric breakdown voltage.By subjecting the material to pulse electric fields,we investigate the insulating properties of the encapsulation material under operational conditions reflective of actual service environments.Dielectric testing and molecular electrostatic potential simulations are further employed to analyse the enhancement of the material's insulating properties due to the introduction of phenyl groups.Research studies indicate that phenyl silicone elastomers exhibit outstanding temperature and electrical resistance,performing well under pulsed electric field.This is associated with the phenyl group's rigid structure,conjugated system,and its electron-withdrawing characteristics.Study provides a theoretical foundation for improving the insulating properties of encapsulation materials and the operational reliability of power electronic devices.展开更多
Small-scale magnetic soft robots are promising candidates for minimally invasive medical applications;however,they struggle to achieve efficient locomotion across various interfaces.In this study,we propose a magnetic...Small-scale magnetic soft robots are promising candidates for minimally invasive medical applications;however,they struggle to achieve efficient locomotion across various interfaces.In this study,we propose a magnetic soft robot that integrates two distinct bio-inspired locomotion modes for enhanced interface navigation.Inspired by water striders’superhydrophobic legs and the meniscus climbing behavior of Pyrrhalta nymphaeae larvae,we developed a rectangular sheet-based robot with hydrophobic surface treatment and novel control strategies.The proposed robot implements two locomotion modes:a bipedal peristaltic locomotion mode(BPLM)and a single-region contact-vibration locomotion mode(SCLM).The BPLM achieves stable movement at 20 mm/s through coordinated front-rear contact points,whereas the SCLM reaches an ultrafast speed of 52 mm/s by optimizing surface tension interactions.The proposed robot demonstrates precise trajectory control with minimal deviations and successfully navigates confined spaces while manipulating objects.Theoretical analysis and experimental validation demonstrate that the integration of triangular wave control signals and steady-state components enables smooth transitions between locomotion modes.This study presents a new paradigm for bio-inspired design of small-scale robots and demonstrates the potential for medical applications requiring precise navigation across multiple terrains.展开更多
Bone defects caused by diseases or surgery are a common clinical problem.Researchers are devoted to finding biological mechanisms that accelerate bone defect repair,which is a complex and continuous process controlled...Bone defects caused by diseases or surgery are a common clinical problem.Researchers are devoted to finding biological mechanisms that accelerate bone defect repair,which is a complex and continuous process controlled by many factors.As members of transcriptional costimulatory molecules,Yes-associated protein(YAP)and transcriptional co-activator with PDZ-binding motif(TAZ)play an important regulatory role in osteogenesis,and they affect cell function by regulating the expression of osteogenic genes in osteogenesis-related cells.Macrophages are an important group of cells whose function is regulated by YAP/TAZ.Currently,the relationship between YAP/TAZ and macrophage polarization has attracted increasing attention.In bone tissue,YAP/TAZ can realize diverse osteogenic regulation by mediating macrophage polarization.Macrophages polarize into M1 and M2 phenotypes under different stimuli.M1 macrophages dominate the inflammatory response by releasing a number of inflammatory mediators in the early phase of bone defect repair,while massive aggregation of M2 macrophages is beneficial for inflammation resolution and tissue repair,as they secrete many anti-inflammatory and osteogenesis-related cytokines.The mechanism of YAP/TAZ-mediated macrophage polarization during osteogenesis warrants further study and it is likely to be a promising strategy for bone defect repair.In this article,we review the effect of Hippo-YAP/TAZ signaling and macrophage polarization on bone defect repair,and highlight the regulation of macrophage polarization by YAP/TAZ.展开更多
Silicone elastomers are widely used to encapsulate power electronic devices.However,such devices may be subjected to square‐wave pulsed voltages with a high rate of change,which can create significant challenges for ...Silicone elastomers are widely used to encapsulate power electronic devices.However,such devices may be subjected to square‐wave pulsed voltages with a high rate of change,which can create significant challenges for encapsulation insulation.In this article,the molecular vibration of silicon elastomer at the edge of pulsed electric field is studied.Firstly,the relationship between the intensity of molecular vibration and the parameters of pulsed electric field is explored.The experimental results show that the amplitude of the vibrations decreases as the pulse‐edge time increases,and it increases linearly as the pulseedge slope increases.Furthermore,the amplitude of the vibrations is proportional to the square of the amplitude of the pulsed electric field,and it increases as the space charge density increases.Then,the force analysis of charged molecule at the pulse edges is calculated,and the theoretical change law of molecular vibration intensity with pulse edge slope is deduced.Comparing the theoretical results with the experimental results,it is found that they are highly consistent.Finally,electrically induced mechanical stress caused by molecular vibration was shown to be an important factor in insulation failure.展开更多
基金supported by the Natural Science Foundation of Ningxia,China(2024AAC02039)the Scientific and Technological Innovation Leadership Talent Program of Ningxia,China(2022GKLRLX07)+1 种基金the National Natural Science Foundation of China(32260727 and 32371924)China Agriculture Research System(CARS-29-zp-6)。
文摘The postharvest senescence phase of table grapes comprises a series of biological processes.MicroRNAs(miRNAs)regulate downstream genes at the post-transcriptional level;however,whether miRNAs are involved in postharvest grape senescence remains unclear.We used small RNA sequencing to identify postharvest-related miRNAs in‘Red Globe'(Vitis vinifera)grapes harvested after 0,30,and 60 d of storage at 4℃(RG0,RG30,RG60).In total,42 known and 219 novel miRNA candidates were obtained.During fruit senescence,the expression of PC-3p-3343_1921,mi R2950,miR395k,miR2111,miR159c,miR169q,PC-5p-1112_4500,and miR167b changed signifcantly(P<0.05).Degradation sequencing identifed 218 targets associated with cell wall organization,tricarboxylic acid(TCA)cycling,pathogen defense,carbon metabolism,hormone signaling,the anthocyanin metabolism pathway,and energy regulation,of which ARF6,GRF3,TCP2,CP1,MYBA2,and WRKY72 were closely related to fruit senescence.We also verified that VIT_00s2146g00010,VIT_02s0012g01750,and VIT_03s0038g00160 with unknown functions are cleaved by senescence-related PC-5p-1112_4500 via the dual luciferase assay,and the transient transformation of grape berries showed that they regulate berry senescence.These results deepen our understanding of the role of mi RNAs in regulating grape berry senescence and prolonging the shelf life of horticultural products.Based on these results,we propose a new theoretical strategy for delaying the postharvest senescence of horticultural products by regulating the expression of key miRNAs(e.g.,PC-5p-1112_4500),thereby extending their shelf life.
基金supported by National Natural Science Foundation of China(Grant Nos.62473277,62473275,62133004,52105072,and 62073230)Jiangsu Provincial Outstanding Youth Program(Grant No.BK20230072)+5 种基金National Key R&D Program of China(Grant Nos.2022YFC3802302 and 2023YFB4705600)Suzhou Industrial Foresight and Key Core Technology Project(Grant No.SYC2022044)Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ24E050004)Shenzhen Polytechnic High-level Talent Start-up Project(Grant No.6023330006K)Shenzhen Science and Technology Program(Grant No.JCYJ20210324132810026)a Grant from Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems,Grants from Jiangsu QingLan Project and Jiangsu 333 high-level talents.
文摘Soft robots, inspired by the flexibility and versatility of biological organisms, have potential in a variety of applications. Recent advancements in magneto-soft robots have demonstrated their abilities to achieve precise remote control through magnetic fields, enabling multi-modal locomotion and complex manipulation tasks. Nonetheless, two main hurdles must be overcome to advance the field: developing a multi-component substrate with embedded magnetic particles to ensure the requisite flexibility and responsiveness, and devising a cost-effective,straightforward method to program three-dimensional distributed magnetic domains without complex processing and expensive machinery. Here, we introduce a cost-effective and simple heat-assisted in-situ integrated molding fabrication method for creating magnetically driven soft robots with three-dimensional programmable magnetic domains. By synthesizing a composite material with neodymium-iron-boron(NdFeB) particles embedded in a polydimethylsiloxane(PDMS) and Ecoflex matrix(PDMS:Ecoflex = 1:2 mass ratio, 50% magnetic particle concentration), we achieved an optimized balance of flexibility, strength, and magnetic responsiveness. The proposed heat-assisted in-situ magnetic domains programming technique,performed at an experimentally optimized temperature of 120℃, resulted in a 2 times magnetization strength(9.5 mT) compared to that at 20℃(4.8 m T), reaching a saturation level comparable to a commercial magnetizer. We demonstrated the versatility of our approach through the fabrication of six kinds of robots, including two kinds of two-dimensional patterned soft robots(2D-PSR), a circular six-pole domain distribution magnetic robot(2D-CSPDMR), a quadrupedal walking magnetic soft robot(QWMSR), an object manipulation robot(OMR), and a hollow thin-walled spherical magneto-soft robot(HTWSMSR). The proposed method provides a practical solution to create highly responsive and adaptable magneto-soft robots.
基金This research is supported by Beijing Municipal Natural Science Foundation(9204023)Ministry of Education“Tiancheng Huizhi”Innovation and Education Promotion Foundation(2018A01012).
文摘This paper focuses on the distribution of passenger flow in Huoying Station,Line 13 of Beijing subway system.The transformation measures taken by Line 13 since operation are firstly summarized.Then the authors elaborate the facilities and equipment of this station,especially the node layout and passenger flow field.An optimization scheme is proposed to rapidly distribute the passenger flow in Huoying Station by adjusting the operation time of the escalator in the direction of Xizhimen.The authors adopt Queuing theory and Anylogic simulation software to simulate the original and the optimized schemes of Huoying Station to distribute the passenger flow.The results of the simulation indicate that the optimized scheme could effectively alleviate the traffic congestion in the hall of Huoying Station,and the pedestrian density in other places of the hall is lowered;passengers could move freely in the hall and no new congestion points would form.The rationality of the scheme is thus proved.
基金supported by the National Natural Science Foundation of China(Nos.52072231,51602187,52072232,51702208)the program for the Young Eastern Scholars Program(No.QD2015028)+1 种基金the Shanghai Municipal Science and Technology Commission(No.18JC1412800)Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-09-E00020)from Shanghai Municipal Education Commission(China)。
文摘Tungsten bronze coatings and films have attracted global attention for their applications in near-infrared(NIR)-shielding windows.However,they are unstable in strong ultraviolet,humid heat,alkaline and/or oxidizing environments and are difficult to be coated on glass surfaces with complex shape.Here,we address these limitations by doping sodium tungsten bronze(Na_(x)WO_(3))into bulk glasses using a simple glass melting method.X-ray diffraction,Raman spectroscopy,X-ray photoelectron spectroscopy,TEM and SEM-EDS characterization confirmed the presence of sodium tungsten bronze(Na_(x)WO_(3))functional units inside the 34SiO_(2)-38B_(2)O_(3)-28NaF glass matrix.Because the functional units are well protected by the glass matrix,the fabricated glasses are stable under hot,humid,oxidizing conditions,as well as under ambient conditions,with no change after 360 days.The NIR-shielding performance of these glasses can be adjusted to as high as 100%by varying WO_(x)concentration(2-8 mol%)and quenching temperature(1000-1400℃).With a content of 6 mol%WO_(x)and a quenching temperature of 1000℃,the bulk glass shows 63%transmission of visible light and only 11%transmission of NIR light at 1100 nm.Thermal insulation experiments show that the NIR-shielding performance of the glasses are far superior to commercial soda lime window glass or indium-doped tin oxide(ITO)glass,and comparable to cesium tungsten bronze coated glass.The novel bulk glasses have higher stability,simpler processing,and can be easily made into complex shapes,making them excellent alternative materials for energy-saving glasses.
基金supported by National Natural Science Foundation of China under Grant Nos.11405022,11475039, 11675095'Dalian High Level Talent Innovation Support Project' under Grant Nos.2015R050 and 2016RQ020
文摘In this paper,removal of nitrogen oxide（NO） is investigated in capacitive atmospheric pressure discharges driven by both radio-frequency（RF） and trapezoidal pulsed power with a onedimensional self-consistent fluid model.The results show that the number density of NO could be reduced significantly once a short pulse of low duty ratio is additionally applied to the RF power.It is found that the process of NO removal by the pulse-modulated RF discharge could be divided into three stages：the quick reaction stage,the NO removal stage,and the sustaining stage.Furthermore,the temporal evolution of particle densities is analyzed,and the key reactions in each stage are discovered.Finally,the influence on the removal efficiency of the voltage amplitude of the pulse and the RF voltage amplitude is investigated.
基金financially supported by the Distinguished Youth Funds of National Natural Science Foundation of China(No.51925402)the Ten Thousand Talent Program of China for Leading Scientists in Science,Technology and Innovation,the Shanxi Science and Technology Major Project Funds(No.20201102004)+3 种基金the Shanxi“1331 Project”Fundsthe Shanxi Province Key Laboratory Construction Project Fundsthe Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(Nos.2021SX-TD001 and 2021SX-TD002)the Shanxi Province Postgraduate Education Innovation Project(No.2021Y191).
文摘The effect of calcination temperature on the pozzolanic activity of maize straw stem ash(MSSA)was evaluated.The MSSA samples calcined at temperature values of 500,700,and 850℃ were dissolved in portlandite solution for 6 h,thereby obtaining residual samples.The MSSA and MSSA residual samples were analyzed using Fourier transform infrared spectroscopy,X-ray powder diffraction scanning electron microscopy,and X-ray photoelectron spectroscopy to determine vibration bonds,minerals,microstructures,and Si 2p transformation behavior.The conductivity,pH value,and loss of conductivity with dissolving time of the MSSA-portlandite mixed solution were also determined.The main oxide composition of MSSA was silica and potassium oxide.The dissolution of the Si^(4+) content of MSSA at 500℃ was higher than those of the other calcination temperatures.The conductivity and loss of conductivity of MSSA at 700℃ were higher than those of the other calcination temperatures at a particular dissolving time due to the higher KCl content in MSSA at 700℃.C-S-H was easily identified in MSSA samples using X-ray powder diffraction,and small cubic and nearly spherical particles of C-S-H were found in the MSSA residual samples.In conclusion,the optimum calcination temperature of MSSA having the best pozzolanic activity is 500℃,but excessive agglomeration must be prevented.
文摘This paper reports on the performance evaluation of a novel latching-type electromagnetic actuator which is designed to be embedded at selected joints along single-port laparoscopic surgical instruments (SLS). The aim of this actuator is to allow these instruments to become articulated with a push of a button in order to provide the optimum angulation required during SLS operations. This new actuator is comprised of electromagnetic coil elements, soft magnetic frames and a permanent magnet. Unlike conventional electromagnetic actuators, latching-type electromagnetic actuators could maintain their positions at either end of the actuation stroke without any power application requirement. In the current design, magnetic attraction forces initiated between the permanent magnet and the magnetic frame are utilised to lock the position of the actuator whilst a certain angulation position of the actuator is achieved as a result of the magnetic repulsion forces established between the permanent magnet and the coil elements. The performance of the new actuator in terms of the output force, maximum angulation and patient’s safety, was evaluated experimentally and the results were found to compare well with those acquired numerically using finite element methods. This actuator was seen to exhibit sufficient actuation forces and hence, it was capable of providing adaptable angulation characteristics for SLS tools. Finally, thermal evaluation of the actuator’s operation was conducted, which was found to be within safety limits specified by clinicians.
基金supported by the National Natural Science Foundation of China (52175100,51975394)the Natural Science Foundation of Jiangsu Province (BK20211336).
文摘The pneumatic gripper in industrial applications has the advantages of structure simplicity and great adaptability,but its gripping power is usually limited due to the low modulus of soft materials.To address this problem,a novel bionic pneumatic gripper inspired by spider legs is proposed.The design has two pairs of symmetrical fingers,each finger consists of two pneumatic actuated joints,two rigid links and one pneumatic soft pad.The rigid link connects the pneumatic chamber which is enclosed in a retractable shell to increase the actuation pressure and the gripping force.The compressibility and elasticity of the soft joint and pad enable the gripper to grasp fragile objects without damage.The modeling of the bionic gripper is developed,and the parameters of the joint actuators are optimized accordingly.The prototype is manufactured and tested with the developed experimental platform,where the gripping force,flexibility and adaptability are evaluated.The results indicate that the designed gripper can grasp irregular and fragile items in sizes from 40 to 140 mm without damage,and the lifting weight is up to 15 N.
基金National Natural Science Foundation of China(Grants 52277155,52177183).
文摘Silicon carbide(SiC)high-voltage,high-power semiconductor devices are essential for next-generation power systems,yet conventional silicone elastomer encapsulation materials suffer from insulation degradation under extreme thermal and electrical stresses,highlighting the critical need for novel dielectric materials.This article brings phenyl groups into the side group of conventional silicone elastomers through ring-opening polymerisation and hydrosilylation,developing phenyl-modified silicone elastomers.The material's superior thermal resistance is substantiated through thermal ageing and thermogravimetric analysis.Moreover,this study delineates the insulating robustness of the material by gauging its dielectric breakdown voltage.By subjecting the material to pulse electric fields,we investigate the insulating properties of the encapsulation material under operational conditions reflective of actual service environments.Dielectric testing and molecular electrostatic potential simulations are further employed to analyse the enhancement of the material's insulating properties due to the introduction of phenyl groups.Research studies indicate that phenyl silicone elastomers exhibit outstanding temperature and electrical resistance,performing well under pulsed electric field.This is associated with the phenyl group's rigid structure,conjugated system,and its electron-withdrawing characteristics.Study provides a theoretical foundation for improving the insulating properties of encapsulation materials and the operational reliability of power electronic devices.
基金supported by the Shenzhen Science and Technology Program(Nos.JCYJ20210324132810026,KQTD20210811090146075,and GXWD20220811164014001)the National Natural Science Foundation of China(Nos.52375175,52005128,62473277,and 52475075)+4 种基金the National Key Research and Development Program of China(No.2022YFC3802302)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515240015)Jiangsu Provincial Outstanding Youth Program(No.BK20230072)Suzhou Industrial Foresight and Key Core Technology Project(No.SYC2022044)a grant from Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems,and grants from Jiangsu Qinglan Project and Jiangsu 333 High-level Talents.
文摘Small-scale magnetic soft robots are promising candidates for minimally invasive medical applications;however,they struggle to achieve efficient locomotion across various interfaces.In this study,we propose a magnetic soft robot that integrates two distinct bio-inspired locomotion modes for enhanced interface navigation.Inspired by water striders’superhydrophobic legs and the meniscus climbing behavior of Pyrrhalta nymphaeae larvae,we developed a rectangular sheet-based robot with hydrophobic surface treatment and novel control strategies.The proposed robot implements two locomotion modes:a bipedal peristaltic locomotion mode(BPLM)and a single-region contact-vibration locomotion mode(SCLM).The BPLM achieves stable movement at 20 mm/s through coordinated front-rear contact points,whereas the SCLM reaches an ultrafast speed of 52 mm/s by optimizing surface tension interactions.The proposed robot demonstrates precise trajectory control with minimal deviations and successfully navigates confined spaces while manipulating objects.Theoretical analysis and experimental validation demonstrate that the integration of triangular wave control signals and steady-state components enables smooth transitions between locomotion modes.This study presents a new paradigm for bio-inspired design of small-scale robots and demonstrates the potential for medical applications requiring precise navigation across multiple terrains.
基金supported by grants from the National Natural Science Foundation of China(No.82170997)the Project of Chengdu Science and Technology Bureau(No.2021-YF05-02054-SN)the Research Funding from West China School/Hospital of Stomatology Sichuan University,China(No.RCDWJS2020-6).
文摘Bone defects caused by diseases or surgery are a common clinical problem.Researchers are devoted to finding biological mechanisms that accelerate bone defect repair,which is a complex and continuous process controlled by many factors.As members of transcriptional costimulatory molecules,Yes-associated protein(YAP)and transcriptional co-activator with PDZ-binding motif(TAZ)play an important regulatory role in osteogenesis,and they affect cell function by regulating the expression of osteogenic genes in osteogenesis-related cells.Macrophages are an important group of cells whose function is regulated by YAP/TAZ.Currently,the relationship between YAP/TAZ and macrophage polarization has attracted increasing attention.In bone tissue,YAP/TAZ can realize diverse osteogenic regulation by mediating macrophage polarization.Macrophages polarize into M1 and M2 phenotypes under different stimuli.M1 macrophages dominate the inflammatory response by releasing a number of inflammatory mediators in the early phase of bone defect repair,while massive aggregation of M2 macrophages is beneficial for inflammation resolution and tissue repair,as they secrete many anti-inflammatory and osteogenesis-related cytokines.The mechanism of YAP/TAZ-mediated macrophage polarization during osteogenesis warrants further study and it is likely to be a promising strategy for bone defect repair.In this article,we review the effect of Hippo-YAP/TAZ signaling and macrophage polarization on bone defect repair,and highlight the regulation of macrophage polarization by YAP/TAZ.
基金National Natural Science Foundation of China,Grant/Award Numbers:51907105,52277155。
文摘Silicone elastomers are widely used to encapsulate power electronic devices.However,such devices may be subjected to square‐wave pulsed voltages with a high rate of change,which can create significant challenges for encapsulation insulation.In this article,the molecular vibration of silicon elastomer at the edge of pulsed electric field is studied.Firstly,the relationship between the intensity of molecular vibration and the parameters of pulsed electric field is explored.The experimental results show that the amplitude of the vibrations decreases as the pulse‐edge time increases,and it increases linearly as the pulseedge slope increases.Furthermore,the amplitude of the vibrations is proportional to the square of the amplitude of the pulsed electric field,and it increases as the space charge density increases.Then,the force analysis of charged molecule at the pulse edges is calculated,and the theoretical change law of molecular vibration intensity with pulse edge slope is deduced.Comparing the theoretical results with the experimental results,it is found that they are highly consistent.Finally,electrically induced mechanical stress caused by molecular vibration was shown to be an important factor in insulation failure.
