Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling ca...Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological features.Firstly,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain synthesis.Secondly,the screw theory is employed to analyze the degree of freedom(DoF)of the capture mechanism.Then,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried out.Combined with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried out.Furthermore,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are analyzed.Finally,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is completed.The work provides technical reserves for the research and development of AUV capture special equipment.展开更多
Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely comme...Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.展开更多
New research and development(R&D)institutions are an important part of the national innovation system,playing an important role in promoting the transformation of scientific and technological achievements.In recen...New research and development(R&D)institutions are an important part of the national innovation system,playing an important role in promoting the transformation of scientific and technological achievements.In recent years,new R&D institutions have gradually become the driving force of innovation-driven development in China.Taking new R&D institutions in Zhejiang Province as the research object,this paper studies the internal talent training path and performance evaluation mechanism of new R&D institutions in Zhejiang Province by using the literature research method,comparison method,case verification method,and other methods.The investigation results show that there are problems such as lack of material and spiritual support and neglect of the absorption of local talents in the internal talent training,and there are problems such as unclear standards,insufficient data,and opaque processes in the performance evaluation mechanism,which greatly affect the establishment and improvement of the performance evaluation mechanism.Given the above problems,this paper puts forward a forward-looking,oriented,flexible,and compatible talent training path and performance evaluation mechanism,hoping to optimize the effective internal talent training path of new R&D institutions,improve the evaluation performance,and promote healthy development of new R&D institutions in Zhejiang Province.展开更多
This study examined the mechanisms for improving the adhesion performance of the asphalt-aggregate interface with two anti-stripping agents and two coupling agents.The investigation of contact behavior between various...This study examined the mechanisms for improving the adhesion performance of the asphalt-aggregate interface with two anti-stripping agents and two coupling agents.The investigation of contact behavior between various asphalt-aggregate surfaces was conducted using molecular dynamics(MD)simulations.The interaction energy and the relative concentration distribution were employed as the parameters to analyze the enhancement mechanisms of anti-stripping agents and coupling agents on the asphalt-aggregate interface.Results indicated that the adhesion at the asphalt-aggregate interface could be strengthened by both anti-stripping agents and coupling agents.Anti-stripping agents primarily improve adhesion through the reinforcement of electrostatic attraction,while coupling agents primarily upgrade adhesion by strengthening the van der Waals.Hence,the molecular dynamics modeling and calculation techniques presented in this study can be utilized to elucidate the development mechanism of the asphalt-aggregate interface through the use of anti-stripping agents and coupling agents.展开更多
In this study,the hydrothermal method was employed to grow submicron CuS on carbon cloth(CC),and the photoreduction method was used to grow Ag nanoparticles on the CuS submicron flowers,thus forming the Ag/CuS/CC cata...In this study,the hydrothermal method was employed to grow submicron CuS on carbon cloth(CC),and the photoreduction method was used to grow Ag nanoparticles on the CuS submicron flowers,thus forming the Ag/CuS/CC catalytic electrode.The application of Ag/CuS/CC electrode-coupled dielectric barrier discharge(DBD)plasma in the disinfection of pathogenic bacteria in water was studied.The Ag/CuS/CC electrode exhibits strong antibacterial activity,and under an external voltage of 30 V,the degradation efficiency of Bacillus subtilis reaches 99.99%within 15 min without regeneration.After five cycles,the inactivation rate of Bacillus subtilis reached 99.99%within 25 min.The practical applicability of the Ag/CuS/CC-coupled DBD system for treating actual wastewater was evaluated,and the changes in biological toxicity were investigated.The results indicate that the prepared Ag/CuS/CC coupled DBD has great potential for safe disinfection of pathogenic bacteria in water through integrated processes.展开更多
The large volumetric variations experienced by metal selenides within conversion reaction result in inferior rate capability and cycling stability,ultimately hindering the achievement of superior electrochemical perfo...The large volumetric variations experienced by metal selenides within conversion reaction result in inferior rate capability and cycling stability,ultimately hindering the achievement of superior electrochemical performance.Herein,metallic Cu_(2)Se encapsulated with N-doped carbon(Cu_(2)Se@NC)was prepared using Cu_(2)O nanocubes as templates through a combination of dopamine polymerization and hightemperature selenization.The unique nanocubic structure and uniform N-doped carbon coating could shorten the ion transport distance,accelerate electron/charge diffusion,and suppress volume variation,ultimately ensuring Cu_(2)Se@NC with excellent electrochemical performance in sodium ion batteries(SIBs)and potassium ion batteries(PIBs).The composite exhibited excellent rate performance(187.7 mA h g^(-1)at 50 A g^(-1)in SIBs and 179.4 mA h g^(-1)at 5 A g^(-1)in PIBs)and cyclic stability(246,8 mA h g^(-1)at 10 A g^(-1)in SIBs over 2500 cycles).The reaction mechanism of intercalation combined with conversion in both SIBs and PIBs was disclosed by in situ X-ray diffraction(XRD)and ex situ transmission electron microscope(TEM).In particular,the final products in PIBs of K_(2)Se and K_(2)Se_(3)species were determined after discharging,which is different from that in SIBs with the final species of Na_(2)Se.The density functional theory calculation showed that carbon induces strong coupling and charge interactions with Cu_(2)Se,leading to the introduction of built-in electric field on heterojunction to improve electron mobility.Significantly,the theoretical calculations discovered that the underlying cause for the relatively superior rate capability in SIBs to that in PIBs is the agile Na~+diffusion with low energy barrier and moderate adsorption energy.These findings offer theoretical support for in-depth understanding of the performance differences of Cu-based materials in different ion storage systems.展开更多
Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effe...Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effectively addresses the aforementioned problems;however,the impact of its quality on lithium-ion transfer and structure durability is yet to be explored.Herein,the influence of an interface conductive network on ionic transport and mechanical stability under fast charging is explored for the first time.2D modeling simulation and Cryo-transmission electron microscopy precisely reveal the mitigation of interface polarization owing to a higher fraction of conductive inorganic species formation in bilayer solid electrolyte interphase is mainly responsible for a linear decrease in ionic diffusion energy barrier.Furthermore,atomic force microscopy and Raman shift exhibit substantial stress dissipation generated by a complete conductive network,which is critical to the linear reduction of electrode residual stress.This study provides insights into the rational design of optimized interface SiO-based anodes with reinforced fast-charging performance.展开更多
The effects of deformation temperature on the transformation-induced plasticity(TRIP)-aided 304L,twinning-induced plasti-city(TWIP)-assisted 316L,and highly alloyed stable 904L austenitic stainless steels were compare...The effects of deformation temperature on the transformation-induced plasticity(TRIP)-aided 304L,twinning-induced plasti-city(TWIP)-assisted 316L,and highly alloyed stable 904L austenitic stainless steels were compared for the first time to tune the mechan-ical properties,strengthening mechanisms,and strength-ductility synergy.For this purpose,the scanning electron microscopy(SEM),electron backscattered diffraction(EBSD),X-ray diffraction(XRD),tensile testing,work-hardening analysis,and thermodynamics calcu-lations were used.The induced plasticity effects led to a high temperature-dependency of work-hardening behavior in the 304L and 316L stainless steels.As the deformation temperature increased,the metastable 304L stainless steel showed the sequence of TRIP,TWIP,and weakening of the induced plasticity mechanism;while the disappearance of the TWIP effect in the 316L stainless steel was also observed.However,the solid-solution strengthening in the 904L superaustenitic stainless steel maintained the tensile properties over a wide temper-ature range,surpassing the performance of 304L and 316L stainless steels.In this regard,the dependency of the total elongation on the de-formation temperature was less pronounced for the 904L alloy due to the absence of additional plasticity mechanisms.These results re-vealed the importance of solid-solution strengthening and the associated high friction stress for superior mechanical behavior over a wide temperature range.展开更多
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
Lignin-derived porous carbons have emerged as promising electrode materials for supercapacitors.However,the challenge remains in designing and controlling their structure to achieve ideal electrochemical performance d...Lignin-derived porous carbons have emerged as promising electrode materials for supercapacitors.However,the challenge remains in designing and controlling their structure to achieve ideal electrochemical performance due to the complex molecular structure of lignin and its intricate chemical reactions during the activation process.In this study,three porous carbons were synthesized from lignin by spray drying and chemical activation with vary-ing KOH ratios.The specific surface area and structural order of the prepared porous carbon continued to increase with the increase of the KOH ratio.Thermogravimetric-mass spectrometry(TG-MS)was employed to track the molecular fragments generated during the pyrolysis of KOH-activated lignin,and the mechanism of the thermochemical conversion was investigated.During the thermochemical conversion of lignin,KOH facili-tated the removal of H2 and CO,leading to the formation of not only more micropores and mesopores,but also more ordered carbon structures.The pore structure exhibited a greater impact than the carbon structure on the electrochemical performance of porous carbon.The optimized porous carbon exhibited a capacitance of 256 F g-1 at a current density of 0.2 A g-1,making it an ideal electrode material for high-performance supercapacitors.展开更多
Potassium-ion batteries(PIBs)are potential“Beyond Li-ion Batteries”candidates for their resource advantage and low standard electrode potential.To date,the research on PIBs is in its early stages,the most urgent tas...Potassium-ion batteries(PIBs)are potential“Beyond Li-ion Batteries”candidates for their resource advantage and low standard electrode potential.To date,the research on PIBs is in its early stages,the most urgent task is to develop high-performance electrode materials and reveal their potassium storage mechanism.For PIBs anode materials,carbon with tunable microstructure,excellent electrochemical activity,nontoxicity and low price is considered as one of the most promising anode materials for commercialization.Although some breakthrough works have emerged,the overall electrochemical performance of the reported carbon anode is still far away from practical application.Herein,we carry out a comprehensive overview of PIBs carbon anode in terms of three aspects of rational design of structure,performance evaluation criteria and characterization of potassium storage mechanism.First,the regulation mechanism of key structural features of carbon anode on its potassium storage performance and the representative structural regulation strategies are introduced.Then,in view of the undefined performance evaluation criteria of PIBs carbon anode,a reference principle for evaluating the potassium storage performance of carbon anode is proposed.Finally,the advanced characterization techniques for the potassium storage mechanism of carbon anode are summarize.This review aims to provide guidance for the development of practical PIBs anode.展开更多
In recent years,with the improvement of the requirements of road performance,modified emulsified asphalts with better performance has gradually replaced the emulsified asphalt and become the primary material for road ...In recent years,with the improvement of the requirements of road performance,modified emulsified asphalts with better performance has gradually replaced the emulsified asphalt and become the primary material for road maintenance.This paper introduces the modified emulsified asphalt materials commonly used in pavement maintenance projects,definitions and modified mechanisms of polymerized styrene butadiene rubber(SBR)modified emulsified asphalt,styrene butadiene styrene block polymer(SBS)modified emulsified asphalt and waterborne epoxy resin(WER)modified emulsified asphalt are summarized.The analysis focused on comparing the effects of modifiers,preparation process,auxiliary additives,and other factors on the performance of modified emulsified asphalt.In this paper,it is considered that the greatest impact on the performance of emulsified asphalt is the modifier,emulsifier mainly affects the speed of breaking the emulsion,stabilizers on the basic performance of emulsified asphalt evaporative residue is small;and when the modifier is distributed in the asphalt in a network,the dosage at this time is the recommended optimum dosage.Finally,this study recommends that in the future,the polymer-asphalt compatibility can be improved through composite modification,chemical grafting and other methods to continue to develop broader applicability and better performance of modified emulsified asphalt.展开更多
Aiming at the problem that the existing ankle rehabilitation robot is difficult to fully fit the complex motion of human ankle joint and has poor human-machine motion compatibility,an equivalent series mechanism model...Aiming at the problem that the existing ankle rehabilitation robot is difficult to fully fit the complex motion of human ankle joint and has poor human-machine motion compatibility,an equivalent series mechanism model that is highly matched with the actual bone structure of the human ankle joint is proposed and mapped into a parallel rehabilita-tion mechanism.The parallel rehabilitation mechanism has two virtual motion centers(VMCs),which can simulate the complex motion of the ankle joint,adapt to the individual differences of various patients,and can meet the reha-bilitation needs of both left and right feet of patients.Firstly,based on the motion properties and physiological structure of the human ankle joint,the mapping relationship between the rehabilitation mechanism and ankle joint is determined,and the series equivalent model of the ankle joint is established.According to the kinematic and con-straint properties of the ankle equivalent model,the configuration design of the parallel ankle rehabilitation robot is carried out.Secondly,according to the intersecting motion planes theory,the full-cycle mobility of the mechanism is proved,and the continuous axis of the mechanism is judged based on the constraint power and its derivative.Then,the kinematics of the parallel ankle rehabilitation robot is analyzed.Finally,based on the OpenSim biomechanical soft-ware,a human-machine coupling rehabilitation simulation model is established to evaluate the rehabilitation effect,which lays the foundation for the formulation of a rehabilitation strategy for the later prototype.展开更多
IEEE 802.11ah is a new Wi-Fi standard for sub-1Ghz communications,aiming to address the challenges of the Internet of Things(IoT).Significant changes in the legacy 802.11 standards have been proposed to improve the ne...IEEE 802.11ah is a new Wi-Fi standard for sub-1Ghz communications,aiming to address the challenges of the Internet of Things(IoT).Significant changes in the legacy 802.11 standards have been proposed to improve the network performance in high contention scenarios,the most important of which is the Restricted Access Window(RAW)mechanism.This mechanism promises to increase the throughput and energy efficiency by dividing stations into different groups.Under this scheme,only the stations belonging to the same group may access the channel,which reduces the collision probability in dense scenarios.However,the standard does not define the RAW grouping strategy.In this paper,we develop a new mathematical model based on the renewal theory,which allows for tracking the number of transmissions within the limited RAW slot contention period defined by the standard.We then analyze and evaluate the performance of RAW mechanism.We also introduce a grouping scheme to organize the stations and channel access time into different groups within the RAW.Furthermore,we propose an algorithm to derive the RAW configuration parameters of a throughput maximizing grouping scheme.We additionally explore the impact of channel errors on the contention within the time-limited RAW slot and the overall RAW optimal configuration.The presented analytical framework can be applied to many other Wi-Fi standards that integrate periodic channel reservations.Extensive simulations using the MATLAB software validate the analytical model and prove the effectiveness of the proposed RAW configuration scheme.展开更多
Magnesium and its alloys,as a promising class of materials,is popular in lightweight application and biomedical implants due to their low density and good biocompatibility.Additive manufacturing(AM)of Mg and its alloy...Magnesium and its alloys,as a promising class of materials,is popular in lightweight application and biomedical implants due to their low density and good biocompatibility.Additive manufacturing(AM)of Mg and its alloys is of growing interest in academia and industry.The domain-by-domain localized forming characteristics of AM leads to unique microstructures and performances of AM-process Mg and its alloys,which are different from those of traditionally manufactured counterparts.However,the intrinsic mechanisms still remain unclear and need to be in-depth explored.Therefore,this work aims to discuss and analyze the possible underlying mechanisms regarding defect appearance and elimination,microstructure formation and evolution,and performance improvement,based on presenting a comprehensive and systematic review on the relationship between process parameters,forming quality,microstructure characteristics and resultant performances.Lastly,some key perspectives requiring focus for further progression are highlighted to promote development of AM-processed Mg and its alloys and accelerate their industrialization.展开更多
Copper matrix composites doped with ceramic particles are known to effectively enhance the mechanical properties,thermal expansion behavior and high-temperature stability of copper while maintaining high thermal and e...Copper matrix composites doped with ceramic particles are known to effectively enhance the mechanical properties,thermal expansion behavior and high-temperature stability of copper while maintaining high thermal and electrical conductivity.This greatly expands the applications of copper as a functional material in thermal and conductive components,including electronic packaging materials and heat sinks,brushes,integrated circuit lead frames.So far,endeavors have been focusing on how to choose suitable ceramic components and fully exert strengthening effect of ceramic particles in the copper matrix.This article reviews and analyzes the effects of preparation techniques and the characteristics of ceramic particles,including ceramic particle content,size,morphology and interfacial bonding,on the diathermancy,electrical conductivity and mechanical behavior of copper matrix composites.The corresponding models and influencing mechanisms are also elaborated in depth.This review contributes to a deep understanding of the strengthening mechanisms and microstructural regulation of ceramic particle reinforced copper matrix composites.By more precise design and manipulation of composite microstructure,the comprehensive properties could be further improved to meet the growing demands of copper matrix composites in a wide range of application fields.展开更多
Although advanced anode materials for the lithium-ion battery have been investigated for decades,a reliable,high-capacity,and durable material that can enable a fast charge remains elusive.Herein,we report that a meta...Although advanced anode materials for the lithium-ion battery have been investigated for decades,a reliable,high-capacity,and durable material that can enable a fast charge remains elusive.Herein,we report that a metal phosphorous trichalcogenide of MnPS_(3)(manganese phosphorus trisulfide),endowed with a unique and layered van der Waals structure,is highly beneficial for the fast insertion/extraction of alkali metal ions and can facilitate changes in the buffer volume during cycles with robust structural stability.The few-layered MnPS_(3)anodes displayed the desirable specific capacity and excellent rate chargeability owing to their good electronic and ionic conductivities.When assembled as a half-cell lithium-ion battery,a high reversible capacity of 380 mA h g^(−1)was maintained by the MnPS_(3)after 3000 cycles at a high current density of 4 A g^(−1),with a capacity retention of close to or above 100%.In full-cell testing,a reversible capacity of 450 mA h g^(−1)after 200 cycles was maintained as well.The results of in-situ TEM revealed that MnPS_(3)nanoflakes maintained a high structural integrity without exhibiting any pulverization after undergoing large volumetric expansion for the insertion of a large number of lithium ions.Their kinetics of lithium-ion diffusion,stable structure,and high pseudocapacitance contributed to their comprehensive performance,for example,a high specific capacity,rapid charge-discharge,and long cyclability.MnPS_(3)is thus an efficient anode for the next generation of batteries with a fast charge/discharge capability.展开更多
In this work,we synthesized MoS_(2)catalyst via one-step hydrothermal method,and systematically investigated the catalytic effect of MoS_(2)on the hydrogen storage properties of MgH_(2).The MgH_(2)-5MoS_(2)composite m...In this work,we synthesized MoS_(2)catalyst via one-step hydrothermal method,and systematically investigated the catalytic effect of MoS_(2)on the hydrogen storage properties of MgH_(2).The MgH_(2)-5MoS_(2)composite milled for 5 h starts to release hydrogen at 259℃.Furthermore,it can desorb 4.0 wt.%hydrogen within 20 min at 280℃,and absorb 4.5 wt.%hydrogen within 5 min at 200℃.Mo and MoS_(2)coexistedin the ball milled sample,whereas only Mo was kept in the sample after dehydrogenation and rehydrogenation,which greatly weakens theMg-H bonds and facilitates the dissociation of MgH_(2)on the surface of Mo(110).The comparative study show that the formed MgS has nocatalytic effect for MgH_(2).We believed that the evolution and the catalytic mechanism of MoS_(2)will provide the theoretical guidance for theapplication of metal sulfide in hydrogen storage materials.展开更多
With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance an...With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance and durability.Polyurethane(PU)has been used in asphalt pavement engineering to enhance the durability and service life of asphalt pavement because of its excellent high-temperature performance,toughness,wear resistance,aging resistance and oil resistance.However,PU modified asphalt technology is still in the exploratory stage.The preparation,modification mechanism and working performances of PU modified asphalt need to be further clarified.Therefore,this paper summarized the research progress of PU modified asphalt and its mixture.The composition of PU modified asphalt was introduced.The addition methods of PU materials and preparation process parameters of the PU modified asphalt were determined.The modification mechanism of PU on asphalt was discussed.The effects of polyurethane on asphalt were analyzed and the road performances of its mixture were evaluated.Finally,the development tendency towards PU modified asphalt and its mixture were forecasted.展开更多
Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a cent...Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a central role in clean energy conversion,enabling a number of sustainable processes for future air battery technologies.Fluorine,as the most electronegative element(4.0)not only can induce more efficient regulation for the electronic structure,but also can bring more abundant defects and other novel effects in materials selection and preparation for favorable catalysis with respect to the other nonmetal elements.However,an individual and comprehensive overview of fluorine-containing functional materials for oxygen electrocatalysis field is still blank.Therefore,it is very meaningful to review the recent progresses of fluorine-containing oxygen electrocatalysts.In this review,we first systematically summarize the controllable preparation methods and their possible development directions based on fluorine-containing materials from four preparation methods.Due to the strong electron-withdrawing properties of fluorine,its control of the electronic structure can effectively enhance the oxygen electrocatalytic activity of the materials.In addition,the catalytic enhancement effect of fluorine on carbonbased materials also includes the prevent oxidation and the layer peeling,and realizes the precise atomic control.And the catalytic improvement mechanism of fluorine containing metal-based compounds also includes the hydration of metal site,the crystal transformation,and the oxygen vacancy induction.Then,based on their various dimensions(0D–3D),we also have summarized the advantages of different morphologies on oxygen electrocatalytic performances.Finally,the prospects and possible future researching direction of F-containing oxygen electrocatalysts are presented(e.g.,novel pathways,advanced methods for measurement and simulation,field assistance and multi-functions).The review is considered valuable and helpful in exploring the novel designs and mechanism analyses of advanced fluorine-containing electrocatalysts.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20220649)the Natural Science Foundation of the Jiangsu Higher Education Institutions(Grant No.23KJB460010)+1 种基金the Key R&D Program of Jiangsu Province(Grant No.BE2022062)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.SJCX23_2143).
文摘Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological features.Firstly,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain synthesis.Secondly,the screw theory is employed to analyze the degree of freedom(DoF)of the capture mechanism.Then,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried out.Combined with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried out.Furthermore,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are analyzed.Finally,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is completed.The work provides technical reserves for the research and development of AUV capture special equipment.
基金This work was supported by the National Natural Science Foundation of China(52203066,51973157,61904123)the Tianjin Natural Science Foundation(18JCQNJC02900)+3 种基金the National innovation and entrepreneurship training program for college students(202310058007)the Tianjin Municipal college students’innovation and entrepreneurship training program(202310058088)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(Grant No.2018KJ196)the State Key Laboratory of Membrane and Membrane Separation,Tiangong University.
文摘Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.
文摘New research and development(R&D)institutions are an important part of the national innovation system,playing an important role in promoting the transformation of scientific and technological achievements.In recent years,new R&D institutions have gradually become the driving force of innovation-driven development in China.Taking new R&D institutions in Zhejiang Province as the research object,this paper studies the internal talent training path and performance evaluation mechanism of new R&D institutions in Zhejiang Province by using the literature research method,comparison method,case verification method,and other methods.The investigation results show that there are problems such as lack of material and spiritual support and neglect of the absorption of local talents in the internal talent training,and there are problems such as unclear standards,insufficient data,and opaque processes in the performance evaluation mechanism,which greatly affect the establishment and improvement of the performance evaluation mechanism.Given the above problems,this paper puts forward a forward-looking,oriented,flexible,and compatible talent training path and performance evaluation mechanism,hoping to optimize the effective internal talent training path of new R&D institutions,improve the evaluation performance,and promote healthy development of new R&D institutions in Zhejiang Province.
文摘This study examined the mechanisms for improving the adhesion performance of the asphalt-aggregate interface with two anti-stripping agents and two coupling agents.The investigation of contact behavior between various asphalt-aggregate surfaces was conducted using molecular dynamics(MD)simulations.The interaction energy and the relative concentration distribution were employed as the parameters to analyze the enhancement mechanisms of anti-stripping agents and coupling agents on the asphalt-aggregate interface.Results indicated that the adhesion at the asphalt-aggregate interface could be strengthened by both anti-stripping agents and coupling agents.Anti-stripping agents primarily improve adhesion through the reinforcement of electrostatic attraction,while coupling agents primarily upgrade adhesion by strengthening the van der Waals.Hence,the molecular dynamics modeling and calculation techniques presented in this study can be utilized to elucidate the development mechanism of the asphalt-aggregate interface through the use of anti-stripping agents and coupling agents.
基金funded by the National College Student Innovation and Entrepreneurship Training Program(No.GJ202323011)。
文摘In this study,the hydrothermal method was employed to grow submicron CuS on carbon cloth(CC),and the photoreduction method was used to grow Ag nanoparticles on the CuS submicron flowers,thus forming the Ag/CuS/CC catalytic electrode.The application of Ag/CuS/CC electrode-coupled dielectric barrier discharge(DBD)plasma in the disinfection of pathogenic bacteria in water was studied.The Ag/CuS/CC electrode exhibits strong antibacterial activity,and under an external voltage of 30 V,the degradation efficiency of Bacillus subtilis reaches 99.99%within 15 min without regeneration.After five cycles,the inactivation rate of Bacillus subtilis reached 99.99%within 25 min.The practical applicability of the Ag/CuS/CC-coupled DBD system for treating actual wastewater was evaluated,and the changes in biological toxicity were investigated.The results indicate that the prepared Ag/CuS/CC coupled DBD has great potential for safe disinfection of pathogenic bacteria in water through integrated processes.
基金The Natural Science Foundation of Henan Province(222300420083)the Opening Foundation of State Key Laboratory of Chemistry and Utilization of Carbon-based Energy Resource of Xinjiang University(KFKT2021004)。
文摘The large volumetric variations experienced by metal selenides within conversion reaction result in inferior rate capability and cycling stability,ultimately hindering the achievement of superior electrochemical performance.Herein,metallic Cu_(2)Se encapsulated with N-doped carbon(Cu_(2)Se@NC)was prepared using Cu_(2)O nanocubes as templates through a combination of dopamine polymerization and hightemperature selenization.The unique nanocubic structure and uniform N-doped carbon coating could shorten the ion transport distance,accelerate electron/charge diffusion,and suppress volume variation,ultimately ensuring Cu_(2)Se@NC with excellent electrochemical performance in sodium ion batteries(SIBs)and potassium ion batteries(PIBs).The composite exhibited excellent rate performance(187.7 mA h g^(-1)at 50 A g^(-1)in SIBs and 179.4 mA h g^(-1)at 5 A g^(-1)in PIBs)and cyclic stability(246,8 mA h g^(-1)at 10 A g^(-1)in SIBs over 2500 cycles).The reaction mechanism of intercalation combined with conversion in both SIBs and PIBs was disclosed by in situ X-ray diffraction(XRD)and ex situ transmission electron microscope(TEM).In particular,the final products in PIBs of K_(2)Se and K_(2)Se_(3)species were determined after discharging,which is different from that in SIBs with the final species of Na_(2)Se.The density functional theory calculation showed that carbon induces strong coupling and charge interactions with Cu_(2)Se,leading to the introduction of built-in electric field on heterojunction to improve electron mobility.Significantly,the theoretical calculations discovered that the underlying cause for the relatively superior rate capability in SIBs to that in PIBs is the agile Na~+diffusion with low energy barrier and moderate adsorption energy.These findings offer theoretical support for in-depth understanding of the performance differences of Cu-based materials in different ion storage systems.
基金the National Natural Science Foundation of China(Nos.22209095 and 22238004).
文摘Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effectively addresses the aforementioned problems;however,the impact of its quality on lithium-ion transfer and structure durability is yet to be explored.Herein,the influence of an interface conductive network on ionic transport and mechanical stability under fast charging is explored for the first time.2D modeling simulation and Cryo-transmission electron microscopy precisely reveal the mitigation of interface polarization owing to a higher fraction of conductive inorganic species formation in bilayer solid electrolyte interphase is mainly responsible for a linear decrease in ionic diffusion energy barrier.Furthermore,atomic force microscopy and Raman shift exhibit substantial stress dissipation generated by a complete conductive network,which is critical to the linear reduction of electrode residual stress.This study provides insights into the rational design of optimized interface SiO-based anodes with reinforced fast-charging performance.
基金Saeed Sadeghpour would like to thank Jane,Aatos Erkon säätiö(JAES),and Tiina ja Antti Herlinin säätiö(TAHS)for their financial support on Advanced Steels for Green Planet Project.The authors would also like to greatly thank the members of the“Formability Laboratory”and“Advanced Steels and Thermomechanically Processed Engineering Ma-terials Laboratory”for their help and support。
文摘The effects of deformation temperature on the transformation-induced plasticity(TRIP)-aided 304L,twinning-induced plasti-city(TWIP)-assisted 316L,and highly alloyed stable 904L austenitic stainless steels were compared for the first time to tune the mechan-ical properties,strengthening mechanisms,and strength-ductility synergy.For this purpose,the scanning electron microscopy(SEM),electron backscattered diffraction(EBSD),X-ray diffraction(XRD),tensile testing,work-hardening analysis,and thermodynamics calcu-lations were used.The induced plasticity effects led to a high temperature-dependency of work-hardening behavior in the 304L and 316L stainless steels.As the deformation temperature increased,the metastable 304L stainless steel showed the sequence of TRIP,TWIP,and weakening of the induced plasticity mechanism;while the disappearance of the TWIP effect in the 316L stainless steel was also observed.However,the solid-solution strengthening in the 904L superaustenitic stainless steel maintained the tensile properties over a wide temper-ature range,surpassing the performance of 304L and 316L stainless steels.In this regard,the dependency of the total elongation on the de-formation temperature was less pronounced for the 904L alloy due to the absence of additional plasticity mechanisms.These results re-vealed the importance of solid-solution strengthening and the associated high friction stress for superior mechanical behavior over a wide temperature range.
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funding from the Key Research and Development Projects of Zhejiang Province(2022C01236)and the Ningbo Top Talent Project.
文摘Lignin-derived porous carbons have emerged as promising electrode materials for supercapacitors.However,the challenge remains in designing and controlling their structure to achieve ideal electrochemical performance due to the complex molecular structure of lignin and its intricate chemical reactions during the activation process.In this study,three porous carbons were synthesized from lignin by spray drying and chemical activation with vary-ing KOH ratios.The specific surface area and structural order of the prepared porous carbon continued to increase with the increase of the KOH ratio.Thermogravimetric-mass spectrometry(TG-MS)was employed to track the molecular fragments generated during the pyrolysis of KOH-activated lignin,and the mechanism of the thermochemical conversion was investigated.During the thermochemical conversion of lignin,KOH facili-tated the removal of H2 and CO,leading to the formation of not only more micropores and mesopores,but also more ordered carbon structures.The pore structure exhibited a greater impact than the carbon structure on the electrochemical performance of porous carbon.The optimized porous carbon exhibited a capacitance of 256 F g-1 at a current density of 0.2 A g-1,making it an ideal electrode material for high-performance supercapacitors.
基金supported financially by the National Key Research and Development Program of China (Grants No. 2017YFA0206301)the National Natural Science Foundation of China (Grants No. 51631001 and 51631001)the China-Germany Collaboration Project (Grants No. M-0199)
文摘Potassium-ion batteries(PIBs)are potential“Beyond Li-ion Batteries”candidates for their resource advantage and low standard electrode potential.To date,the research on PIBs is in its early stages,the most urgent task is to develop high-performance electrode materials and reveal their potassium storage mechanism.For PIBs anode materials,carbon with tunable microstructure,excellent electrochemical activity,nontoxicity and low price is considered as one of the most promising anode materials for commercialization.Although some breakthrough works have emerged,the overall electrochemical performance of the reported carbon anode is still far away from practical application.Herein,we carry out a comprehensive overview of PIBs carbon anode in terms of three aspects of rational design of structure,performance evaluation criteria and characterization of potassium storage mechanism.First,the regulation mechanism of key structural features of carbon anode on its potassium storage performance and the representative structural regulation strategies are introduced.Then,in view of the undefined performance evaluation criteria of PIBs carbon anode,a reference principle for evaluating the potassium storage performance of carbon anode is proposed.Finally,the advanced characterization techniques for the potassium storage mechanism of carbon anode are summarize.This review aims to provide guidance for the development of practical PIBs anode.
基金The authors acknowledge the financial support from National Natural Science Foundation of China(No.51968006).
文摘In recent years,with the improvement of the requirements of road performance,modified emulsified asphalts with better performance has gradually replaced the emulsified asphalt and become the primary material for road maintenance.This paper introduces the modified emulsified asphalt materials commonly used in pavement maintenance projects,definitions and modified mechanisms of polymerized styrene butadiene rubber(SBR)modified emulsified asphalt,styrene butadiene styrene block polymer(SBS)modified emulsified asphalt and waterborne epoxy resin(WER)modified emulsified asphalt are summarized.The analysis focused on comparing the effects of modifiers,preparation process,auxiliary additives,and other factors on the performance of modified emulsified asphalt.In this paper,it is considered that the greatest impact on the performance of emulsified asphalt is the modifier,emulsifier mainly affects the speed of breaking the emulsion,stabilizers on the basic performance of emulsified asphalt evaporative residue is small;and when the modifier is distributed in the asphalt in a network,the dosage at this time is the recommended optimum dosage.Finally,this study recommends that in the future,the polymer-asphalt compatibility can be improved through composite modification,chemical grafting and other methods to continue to develop broader applicability and better performance of modified emulsified asphalt.
基金Supported by National Natural Science Foundation of China(Grant No.52075145)S&T Program of Hebei Province of China(Grant No.20281805Z)+1 种基金Hebei Provincial Natural Science Foundation of China(Grant No.E2022202130)Central Government Guides Basic Research Projects of Local Science and Technology Development Funds of China(Grant No.206Z1801G).
文摘Aiming at the problem that the existing ankle rehabilitation robot is difficult to fully fit the complex motion of human ankle joint and has poor human-machine motion compatibility,an equivalent series mechanism model that is highly matched with the actual bone structure of the human ankle joint is proposed and mapped into a parallel rehabilita-tion mechanism.The parallel rehabilitation mechanism has two virtual motion centers(VMCs),which can simulate the complex motion of the ankle joint,adapt to the individual differences of various patients,and can meet the reha-bilitation needs of both left and right feet of patients.Firstly,based on the motion properties and physiological structure of the human ankle joint,the mapping relationship between the rehabilitation mechanism and ankle joint is determined,and the series equivalent model of the ankle joint is established.According to the kinematic and con-straint properties of the ankle equivalent model,the configuration design of the parallel ankle rehabilitation robot is carried out.Secondly,according to the intersecting motion planes theory,the full-cycle mobility of the mechanism is proved,and the continuous axis of the mechanism is judged based on the constraint power and its derivative.Then,the kinematics of the parallel ankle rehabilitation robot is analyzed.Finally,based on the OpenSim biomechanical soft-ware,a human-machine coupling rehabilitation simulation model is established to evaluate the rehabilitation effect,which lays the foundation for the formulation of a rehabilitation strategy for the later prototype.
基金supported by the Spanish Ministry of Science,Education and Universities,the European Regional Development Fund and the State Research Agency,Grant No.RTI2018-098156-B-C52.
文摘IEEE 802.11ah is a new Wi-Fi standard for sub-1Ghz communications,aiming to address the challenges of the Internet of Things(IoT).Significant changes in the legacy 802.11 standards have been proposed to improve the network performance in high contention scenarios,the most important of which is the Restricted Access Window(RAW)mechanism.This mechanism promises to increase the throughput and energy efficiency by dividing stations into different groups.Under this scheme,only the stations belonging to the same group may access the channel,which reduces the collision probability in dense scenarios.However,the standard does not define the RAW grouping strategy.In this paper,we develop a new mathematical model based on the renewal theory,which allows for tracking the number of transmissions within the limited RAW slot contention period defined by the standard.We then analyze and evaluate the performance of RAW mechanism.We also introduce a grouping scheme to organize the stations and channel access time into different groups within the RAW.Furthermore,we propose an algorithm to derive the RAW configuration parameters of a throughput maximizing grouping scheme.We additionally explore the impact of channel errors on the contention within the time-limited RAW slot and the overall RAW optimal configuration.The presented analytical framework can be applied to many other Wi-Fi standards that integrate periodic channel reservations.Extensive simulations using the MATLAB software validate the analytical model and prove the effectiveness of the proposed RAW configuration scheme.
基金supported by Scientific Research Program Funded by Shaanxi Provincial Education Department(Program No.22JK0479)Research Start-up Project of Xi’an University of Technology(Grant No.101-256082204)+5 种基金International Science and Technology Cooperation Program of Shaanxi Province(No.2023-GHZD-50)Project of Science and Technology Shaanxi Province(No.2023-JC-YB-412)Project of Science and Technology Shaanxi Province(No.2023-JC-QN-0573)Projects of Major Innovation Platforms for Scientific and Technological and Local Transformation of Scientific and Technological Achievements of Xi’an(No.20GXSF0003)Projects of Major Scientific and Technological Achievements Local Transformation of Xi’an(No.2022JHZDZH-0039)Higher Education Institution Discipline Innovation and Intelligence Base of Shaanxi Provincial(No.S2021-ZC-GXYZ-0011).
文摘Magnesium and its alloys,as a promising class of materials,is popular in lightweight application and biomedical implants due to their low density and good biocompatibility.Additive manufacturing(AM)of Mg and its alloys is of growing interest in academia and industry.The domain-by-domain localized forming characteristics of AM leads to unique microstructures and performances of AM-process Mg and its alloys,which are different from those of traditionally manufactured counterparts.However,the intrinsic mechanisms still remain unclear and need to be in-depth explored.Therefore,this work aims to discuss and analyze the possible underlying mechanisms regarding defect appearance and elimination,microstructure formation and evolution,and performance improvement,based on presenting a comprehensive and systematic review on the relationship between process parameters,forming quality,microstructure characteristics and resultant performances.Lastly,some key perspectives requiring focus for further progression are highlighted to promote development of AM-processed Mg and its alloys and accelerate their industrialization.
基金supported by National Natural Science Foundation of China(No.51971101)Science and Technology Development Program of Jilin Province,China(20230201146G X)Exploration Foundation of State Key Laboratory of Automotive Simulation and Control(asclzytsxm-202015)。
文摘Copper matrix composites doped with ceramic particles are known to effectively enhance the mechanical properties,thermal expansion behavior and high-temperature stability of copper while maintaining high thermal and electrical conductivity.This greatly expands the applications of copper as a functional material in thermal and conductive components,including electronic packaging materials and heat sinks,brushes,integrated circuit lead frames.So far,endeavors have been focusing on how to choose suitable ceramic components and fully exert strengthening effect of ceramic particles in the copper matrix.This article reviews and analyzes the effects of preparation techniques and the characteristics of ceramic particles,including ceramic particle content,size,morphology and interfacial bonding,on the diathermancy,electrical conductivity and mechanical behavior of copper matrix composites.The corresponding models and influencing mechanisms are also elaborated in depth.This review contributes to a deep understanding of the strengthening mechanisms and microstructural regulation of ceramic particle reinforced copper matrix composites.By more precise design and manipulation of composite microstructure,the comprehensive properties could be further improved to meet the growing demands of copper matrix composites in a wide range of application fields.
基金National Natural Science Foundation of China,Grant/Award Numbers:11902185,11972219,U21A2086National Key Research and Development Program of China,Grant/Award Number:2020YFB0704503+1 种基金Young Elite Scientist Sponsorship Program by CAST,Grant/Award Number:2019QNRC001Shanghai Sailing Program,Grant/Award Number:19YF1415100。
文摘Although advanced anode materials for the lithium-ion battery have been investigated for decades,a reliable,high-capacity,and durable material that can enable a fast charge remains elusive.Herein,we report that a metal phosphorous trichalcogenide of MnPS_(3)(manganese phosphorus trisulfide),endowed with a unique and layered van der Waals structure,is highly beneficial for the fast insertion/extraction of alkali metal ions and can facilitate changes in the buffer volume during cycles with robust structural stability.The few-layered MnPS_(3)anodes displayed the desirable specific capacity and excellent rate chargeability owing to their good electronic and ionic conductivities.When assembled as a half-cell lithium-ion battery,a high reversible capacity of 380 mA h g^(−1)was maintained by the MnPS_(3)after 3000 cycles at a high current density of 4 A g^(−1),with a capacity retention of close to or above 100%.In full-cell testing,a reversible capacity of 450 mA h g^(−1)after 200 cycles was maintained as well.The results of in-situ TEM revealed that MnPS_(3)nanoflakes maintained a high structural integrity without exhibiting any pulverization after undergoing large volumetric expansion for the insertion of a large number of lithium ions.Their kinetics of lithium-ion diffusion,stable structure,and high pseudocapacitance contributed to their comprehensive performance,for example,a high specific capacity,rapid charge-discharge,and long cyclability.MnPS_(3)is thus an efficient anode for the next generation of batteries with a fast charge/discharge capability.
基金supported by the financial supports from Science and Technology Commission of Shanghai Municipality(No.19ZR1418400)the National Natural Science Foundation of China(No.51971126)+1 种基金Guangdong Innovation Research Team for Higher Education(2017KCXTD030)the Science and Technology Committee of Shanghai(19010500400).
文摘In this work,we synthesized MoS_(2)catalyst via one-step hydrothermal method,and systematically investigated the catalytic effect of MoS_(2)on the hydrogen storage properties of MgH_(2).The MgH_(2)-5MoS_(2)composite milled for 5 h starts to release hydrogen at 259℃.Furthermore,it can desorb 4.0 wt.%hydrogen within 20 min at 280℃,and absorb 4.5 wt.%hydrogen within 5 min at 200℃.Mo and MoS_(2)coexistedin the ball milled sample,whereas only Mo was kept in the sample after dehydrogenation and rehydrogenation,which greatly weakens theMg-H bonds and facilitates the dissociation of MgH_(2)on the surface of Mo(110).The comparative study show that the formed MgS has nocatalytic effect for MgH_(2).We believed that the evolution and the catalytic mechanism of MoS_(2)will provide the theoretical guidance for theapplication of metal sulfide in hydrogen storage materials.
基金supported by Innovation Capability Support Program of Shaanxi(2022TD-07).
文摘With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance and durability.Polyurethane(PU)has been used in asphalt pavement engineering to enhance the durability and service life of asphalt pavement because of its excellent high-temperature performance,toughness,wear resistance,aging resistance and oil resistance.However,PU modified asphalt technology is still in the exploratory stage.The preparation,modification mechanism and working performances of PU modified asphalt need to be further clarified.Therefore,this paper summarized the research progress of PU modified asphalt and its mixture.The composition of PU modified asphalt was introduced.The addition methods of PU materials and preparation process parameters of the PU modified asphalt were determined.The modification mechanism of PU on asphalt was discussed.The effects of polyurethane on asphalt were analyzed and the road performances of its mixture were evaluated.Finally,the development tendency towards PU modified asphalt and its mixture were forecasted.
基金supported by the National Natural Science Foundation of China,China(52203066,51973157,51673148 and 51678411)the Science and Technology Plans of Tianjin,China(19PTSYJC00010)+3 种基金China Postdoctoral Science Foundation Grant,China(2019M651047)the Tianjin Research Innovation Project for Postgraduate Students,China(2020YJSB062)the Tianjin Municipal College Student’Innovation And Entrepreneurship Training Program,China(202110058052)the National Innovation and Entrepreneurship Training Program for College Students,China(202110058017)。
文摘Non-renewable fossil fuels have led to serious problems such as global warming,environmental pollution,etc.Oxygen electrocatalysis including oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)plays a central role in clean energy conversion,enabling a number of sustainable processes for future air battery technologies.Fluorine,as the most electronegative element(4.0)not only can induce more efficient regulation for the electronic structure,but also can bring more abundant defects and other novel effects in materials selection and preparation for favorable catalysis with respect to the other nonmetal elements.However,an individual and comprehensive overview of fluorine-containing functional materials for oxygen electrocatalysis field is still blank.Therefore,it is very meaningful to review the recent progresses of fluorine-containing oxygen electrocatalysts.In this review,we first systematically summarize the controllable preparation methods and their possible development directions based on fluorine-containing materials from four preparation methods.Due to the strong electron-withdrawing properties of fluorine,its control of the electronic structure can effectively enhance the oxygen electrocatalytic activity of the materials.In addition,the catalytic enhancement effect of fluorine on carbonbased materials also includes the prevent oxidation and the layer peeling,and realizes the precise atomic control.And the catalytic improvement mechanism of fluorine containing metal-based compounds also includes the hydration of metal site,the crystal transformation,and the oxygen vacancy induction.Then,based on their various dimensions(0D–3D),we also have summarized the advantages of different morphologies on oxygen electrocatalytic performances.Finally,the prospects and possible future researching direction of F-containing oxygen electrocatalysts are presented(e.g.,novel pathways,advanced methods for measurement and simulation,field assistance and multi-functions).The review is considered valuable and helpful in exploring the novel designs and mechanism analyses of advanced fluorine-containing electrocatalysts.