Sustainable nitrogen fixation driven by renewable energy sources under mild conditions has been widely sought to replace the industrial Haber-Bosch process.The fixation of nitrogen in the form of NO_(x)^(-)and NH_4^(+...Sustainable nitrogen fixation driven by renewable energy sources under mild conditions has been widely sought to replace the industrial Haber-Bosch process.The fixation of nitrogen in the form of NO_(x)^(-)and NH_4^(+)into aqueous solutions using electricity-driven gas-liquid discharge plasma is considered a promising prescription.In this paper,a scalable bubble discharge excited by nanosecond pulse power is employed for nitrogen fixation in the liquid phase.The nitrogen fixation performance and the mechanisms are analyzed by varying the power supply parameters,working gas flow rate and composition.The results show that an increase in voltage and frequency can result in an enhanced NO_(3)^(-)yield.Increases in the gas flow rate can result in inadequate activation of the working gas,which together with more inefficient mass transfer efficiencies can reduce the yield.The addition of O_(2) effectively elevates NO_(3)^(-)production while simultaneously inhibiting NH_4^(+) production.The addition of H_(2)O vapor increases the production of OH and H,thereby promoting the generation of reactive nitrogen and enhancing the yield of nitrogen fixation.However,the excessive addition of O_(2) and H_(2)O vapor results in negative effect on the yield of nitrogen fixation,due to the significant weakening of the discharge intensity.The optimal nitrogen fixation yield was up to 16.5 μmol/min,while the optimal energy consumption was approximately 21.3 MJ/mol in this study.Finally,the mechanism related to nitrogen fixation is discussed through the optical emission spectral(OES) information in conjunction with the simulation of energy loss paths in the plasma by BOLSIG+.The work advances knowledge of the effect of parameter variations on nitrogen fixation by gas-liquid discharge for higher yield and energy production.展开更多
Anterior cruciate ligament(ACL)injuries of the knee are one of the most common and serious athletic injuries.The widely used cortical suspension fixation buttons for ligament reconstruction are permanent implants,part...Anterior cruciate ligament(ACL)injuries of the knee are one of the most common and serious athletic injuries.The widely used cortical suspension fixation buttons for ligament reconstruction are permanent implants,particularly those made from conventional steel or titanium alloys.In this study,a biodegradable Zn-0.45Mn-0.2Mg(ZMM42)alloy with the yield strength of 300.4 MPa and tensile strength of 329.8 MPa was prepared through hot extrusion.The use of zinc alloys in the preparation of cortical suspension fixation buttons was proposed for the first time.After 35 d of immersion in simulated body fluids,the ZMM42 alloy fixation buttons were degraded at a rate of 44μm/a,and the fixation strength was retained(379.55 N)in the traction loops.Simultaneously,the ZMM42 alloy fixation buttons exhibited an increase in MC3T3-E1 cell viability and high antibacterial activity against Escherichia coli and Staphylococcus aureus.These results reveal the potential of biodegradable zinc alloys for use as ligament reconstruction materials and for developing diverse zinc alloy cortical suspension fixation devices.展开更多
The Ortho-SUV frame,a novel external fixator,can effectively treat limb deformities and fractures.Its kinematics is used when it is necessary to achieve bone movements with high precision.In this work,the kinematics m...The Ortho-SUV frame,a novel external fixator,can effectively treat limb deformities and fractures.Its kinematics is used when it is necessary to achieve bone movements with high precision.In this work,the kinematics model of the Ortho-SUV frame is established by six pose parameters,and its forward and inverse solutions are given.There is no need to solve nonlinear high-coupling equations with trigonometric functions in this solution method due to its special structure.By numerical examples and simulated orthopedic experiment of tibial fracture,the correctness and accuracy of the kinematics model and its solutions are verified.Besides,on the basis of kinematics analysis,the position workspace and orientation workspace of the Ortho-SUV frame are simulated in Matlab,which can help surgeons choose suitable device dimensions.The kinematics analysis provides a theoretical basis for the Ortho-SUV frame to be used in orthopedic treatment.展开更多
Based on the analysis of the structure and properties of gardenia, the gardenia was extracted in neutral bath. The mordant dyeing of cotton, including pre-mordant, one-bath and post-mordant were studied, and the dyein...Based on the analysis of the structure and properties of gardenia, the gardenia was extracted in neutral bath. The mordant dyeing of cotton, including pre-mordant, one-bath and post-mordant were studied, and the dyeing properties such as dye K/S value and color fastness were investigated. According to the structure and property of mordants including alum, copper sulfate, iron sulfate and rare earth, the interaction mechanisms among gardenia, mordant and cotton fibers were analyzed and the processing factors affecting the mordant dyeing were discussed. As a result, gardenia showed favorable dyeing performance on cotton. The soaping color fastness and crocking fastness were improved by 0.5-1 grade after fixation process with the selected dye-fixing agent and optimized process conditions. The dyeing process and fixation process were optimized.展开更多
In the field of tissue engineering,there is significant subsidence of the porous design scaffold several months after implantation.To avoid stress shielding and stimulate bone and cartilage ingrowth,high scaffold poro...In the field of tissue engineering,there is significant subsidence of the porous design scaffold several months after implantation.To avoid stress shielding and stimulate bone and cartilage ingrowth,high scaffold porosity is needed to diminish the mechanical properties of the scaffold.The closer the mechanical properties of the scaffold are to those of surrounding tissues,the better biological properties it will get.Besides,adequate mechanical stability is needed as the scaffold needs to be well fixed in the target area and it will endure load after surgery.Evaluating the mechanical fixation of the scaffold at the initial stage and the long-term performance of a scaffold for in vivo study is hard,as no facility can be put into the target area for the friction test.This study investigated the mechanical stability of the biomimetic scaffold at the initial stage of implantation by finite element analysis(FEA).According to in vivo study,scaffold could not maintain its original position and would sink 1-2 mm in the target area.The simulation results suggested that mechanical loading is not the main reason for scaffold subsidence.展开更多
In the experiment, we inserted the implants coated with TC4 fibers and particles into the bones of dogs.The histological characters of the bone ingrowth and the state of bone remodelling at interface were observed. An...In the experiment, we inserted the implants coated with TC4 fibers and particles into the bones of dogs.The histological characters of the bone ingrowth and the state of bone remodelling at interface were observed. And then the whole course of the fatigue injuries accumulation at the interface was monitored by scanning electron microscopy equipped with fatigue stage. Experiments show that the collagen fibers of bone interweave in the porosity of implants, which were strengthened by hydroxyapatite crystal. The collagen fibers were bound to the porous layer implant and the binding strength was enhanced by hydroxyapatite crystal. The remodelling state of bone in pores of implant and around the interface play a key role in determining the fatigue strength and the life span of the interface between bone and implant. Therefore, we consider that the interlocking fixation between bone and implant can be more exactly explained as binding mechanism.展开更多
基金National Natural Science Foundation of China (Grant Nos. 52277151 and 51907088)。
文摘Sustainable nitrogen fixation driven by renewable energy sources under mild conditions has been widely sought to replace the industrial Haber-Bosch process.The fixation of nitrogen in the form of NO_(x)^(-)and NH_4^(+)into aqueous solutions using electricity-driven gas-liquid discharge plasma is considered a promising prescription.In this paper,a scalable bubble discharge excited by nanosecond pulse power is employed for nitrogen fixation in the liquid phase.The nitrogen fixation performance and the mechanisms are analyzed by varying the power supply parameters,working gas flow rate and composition.The results show that an increase in voltage and frequency can result in an enhanced NO_(3)^(-)yield.Increases in the gas flow rate can result in inadequate activation of the working gas,which together with more inefficient mass transfer efficiencies can reduce the yield.The addition of O_(2) effectively elevates NO_(3)^(-)production while simultaneously inhibiting NH_4^(+) production.The addition of H_(2)O vapor increases the production of OH and H,thereby promoting the generation of reactive nitrogen and enhancing the yield of nitrogen fixation.However,the excessive addition of O_(2) and H_(2)O vapor results in negative effect on the yield of nitrogen fixation,due to the significant weakening of the discharge intensity.The optimal nitrogen fixation yield was up to 16.5 μmol/min,while the optimal energy consumption was approximately 21.3 MJ/mol in this study.Finally,the mechanism related to nitrogen fixation is discussed through the optical emission spectral(OES) information in conjunction with the simulation of energy loss paths in the plasma by BOLSIG+.The work advances knowledge of the effect of parameter variations on nitrogen fixation by gas-liquid discharge for higher yield and energy production.
基金financially supported by the Xiongan New Area Science and Technology Innovation Project,China(No.2022XACX0600)the Beijing Nova Program Cross Cooperation Program,China(No.20220484178)。
文摘Anterior cruciate ligament(ACL)injuries of the knee are one of the most common and serious athletic injuries.The widely used cortical suspension fixation buttons for ligament reconstruction are permanent implants,particularly those made from conventional steel or titanium alloys.In this study,a biodegradable Zn-0.45Mn-0.2Mg(ZMM42)alloy with the yield strength of 300.4 MPa and tensile strength of 329.8 MPa was prepared through hot extrusion.The use of zinc alloys in the preparation of cortical suspension fixation buttons was proposed for the first time.After 35 d of immersion in simulated body fluids,the ZMM42 alloy fixation buttons were degraded at a rate of 44μm/a,and the fixation strength was retained(379.55 N)in the traction loops.Simultaneously,the ZMM42 alloy fixation buttons exhibited an increase in MC3T3-E1 cell viability and high antibacterial activity against Escherichia coli and Staphylococcus aureus.These results reveal the potential of biodegradable zinc alloys for use as ligament reconstruction materials and for developing diverse zinc alloy cortical suspension fixation devices.
基金National Key Research & Development Program of China(No.2017YFB1302901)
文摘The Ortho-SUV frame,a novel external fixator,can effectively treat limb deformities and fractures.Its kinematics is used when it is necessary to achieve bone movements with high precision.In this work,the kinematics model of the Ortho-SUV frame is established by six pose parameters,and its forward and inverse solutions are given.There is no need to solve nonlinear high-coupling equations with trigonometric functions in this solution method due to its special structure.By numerical examples and simulated orthopedic experiment of tibial fracture,the correctness and accuracy of the kinematics model and its solutions are verified.Besides,on the basis of kinematics analysis,the position workspace and orientation workspace of the Ortho-SUV frame are simulated in Matlab,which can help surgeons choose suitable device dimensions.The kinematics analysis provides a theoretical basis for the Ortho-SUV frame to be used in orthopedic treatment.
文摘Based on the analysis of the structure and properties of gardenia, the gardenia was extracted in neutral bath. The mordant dyeing of cotton, including pre-mordant, one-bath and post-mordant were studied, and the dyeing properties such as dye K/S value and color fastness were investigated. According to the structure and property of mordants including alum, copper sulfate, iron sulfate and rare earth, the interaction mechanisms among gardenia, mordant and cotton fibers were analyzed and the processing factors affecting the mordant dyeing were discussed. As a result, gardenia showed favorable dyeing performance on cotton. The soaping color fastness and crocking fastness were improved by 0.5-1 grade after fixation process with the selected dye-fixing agent and optimized process conditions. The dyeing process and fixation process were optimized.
基金financially supported by Versus Arthritis Research UK (No.21977)European Commission via a H2020-MSCA-RISE Programme (BAMOS,No.734156)+2 种基金Innovative UK via Newton Fund (No.102872)Engineering and Physical Science Research Council (EPSRC) via DTP CASE Programme (No.EP/T517793/1)the Intergovernmental Cooperation in Science and Technology of China (No.2016YFE0125300)
文摘In the field of tissue engineering,there is significant subsidence of the porous design scaffold several months after implantation.To avoid stress shielding and stimulate bone and cartilage ingrowth,high scaffold porosity is needed to diminish the mechanical properties of the scaffold.The closer the mechanical properties of the scaffold are to those of surrounding tissues,the better biological properties it will get.Besides,adequate mechanical stability is needed as the scaffold needs to be well fixed in the target area and it will endure load after surgery.Evaluating the mechanical fixation of the scaffold at the initial stage and the long-term performance of a scaffold for in vivo study is hard,as no facility can be put into the target area for the friction test.This study investigated the mechanical stability of the biomimetic scaffold at the initial stage of implantation by finite element analysis(FEA).According to in vivo study,scaffold could not maintain its original position and would sink 1-2 mm in the target area.The simulation results suggested that mechanical loading is not the main reason for scaffold subsidence.
文摘In the experiment, we inserted the implants coated with TC4 fibers and particles into the bones of dogs.The histological characters of the bone ingrowth and the state of bone remodelling at interface were observed. And then the whole course of the fatigue injuries accumulation at the interface was monitored by scanning electron microscopy equipped with fatigue stage. Experiments show that the collagen fibers of bone interweave in the porosity of implants, which were strengthened by hydroxyapatite crystal. The collagen fibers were bound to the porous layer implant and the binding strength was enhanced by hydroxyapatite crystal. The remodelling state of bone in pores of implant and around the interface play a key role in determining the fatigue strength and the life span of the interface between bone and implant. Therefore, we consider that the interlocking fixation between bone and implant can be more exactly explained as binding mechanism.
