The electromagnetic properties of high temperature superconductors(HTS)are characterized with the explicit intent to improve their integration in electric power systems.A tape and a coil made of Bismuth Strontium Calc...The electromagnetic properties of high temperature superconductors(HTS)are characterized with the explicit intent to improve their integration in electric power systems.A tape and a coil made of Bismuth Strontium Calcium Copper Oxide(BSCCO)are considered in the presence of electromagnetically active materials in order to mimic properly the electromagnetic environment typical of electrical machines.The characterization consists of the determining the critical current and the AC losses at different values of the frequency and the transport current.The effects induced by the proximity of the active materials are studied and some related experimental issues are analyzedc.展开更多
The microstructures on electrode level are crucial for battery performance, but the ambiguous understanding of both electrode microstructures and their structuring process causes critical challenges in controlling and...The microstructures on electrode level are crucial for battery performance, but the ambiguous understanding of both electrode microstructures and their structuring process causes critical challenges in controlling and evaluating the electrode quality during fabrication. In this review, analogous to the cell microenvironment well-known in biology, we introduce the concept of ‘‘active material microenvironment”(ME@AM)that is built by the ion/electron transport structures surrounding the AMs, for better understanding the significance of the electrode microstructures. Further, the scientific significance of electrode processing for electrode quality control is highlighted by its strong links to the structuring and quality control of ME@AM. Meanwhile, the roles of electrode rheology in both electrode structuring and structural characterizations involved in the entire electrode manufacturing process(i.e., slurry preparation, coating/printing/extrusion, drying and calendering) are specifically detailed. The advantages of electrode rheology testing on in-situ characterizations of the electrode qualities/structures are emphasized. This review provides a glimpse of the electrode rheology engaged in electrode manufacturing process and new insights into the understanding and effective regulation of electrode microstructures for future high-performance batteries.展开更多
Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadoli...Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadolinium ion selective electrode besides the effects of their structures.1.Effect of preparation process of the grafted polymers on the properties ofgadolinium ion selective electrodesThe electrode membranes which consist of functional polymers as active materials were prepared by re-action of gadolinium chloride with the radiation grafted clmer of acrlic acid and polystyrene of which展开更多
In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- ti...In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes.展开更多
Sulfurized polyacrylonitrile(SPAN)has emerged as an excellent cathode material for lithium–sulfur batteries(LiSBs),and it addresses the shuttle effect through a solid‒solid reaction.However,the actual sulfur loadings...Sulfurized polyacrylonitrile(SPAN)has emerged as an excellent cathode material for lithium–sulfur batteries(LiSBs),and it addresses the shuttle effect through a solid‒solid reaction.However,the actual sulfur loadings in SPAN often remain below 40 wt%.Due to the susceptibility of polysulfides-to-nucleophilic reactions with electrolytes,achieving physical encapsulation of elemental sulfur is a challenging task.In this study,a free-standing cathode material with a high sulfur/selenium(S/Se)loading of 55 wt%was fabricated by introducing SeS_(x) into the unique lotus root-like pores of porous SeS_(x)PAN nanofiber membranes by electrospinning and a two-step heat treatment.Insoluble compounds were formed due to nucleophilic interactions between lithium polyselenosulfides(LiSeSx)and the electrolyte,which potently blocked the existing lotus root-like pores and facilitated the creation of a thin cathode–electrolyte interphase on the fiber surface.This dual functionality of LiSeS_(x) safeguarded the active material embedded within the porous structure.The SeS_(15)PAN cathode exhibited remarkable cycling stability with almost no degradation after 200 cycles at 0.2 C,along with a high discharge capacity of 580 mAh/g.This approach presents a solution for addressing the insufficient sulfur content in SPAN.展开更多
The piezoelectric materials are used to investigate the active vibration control of ordered/disordered periodic two-span beams. The equation of motion of each sub-beam with piezoelectric patches is established based o...The piezoelectric materials are used to investigate the active vibration control of ordered/disordered periodic two-span beams. The equation of motion of each sub-beam with piezoelectric patches is established based on Hamilton＇s principle with an assumed mode method. The velocity feedback control algorithm is used to design the controller. The free and forced vibration behaviors of the two-span beams with the piezoelectric actuators and sensors are analyzed. The vibration properties of the disordered two-span beams caused by misplacing the middle support are also researched. In addition, the effects of the length disorder degree on the vibration performances of the disordered beams are investigated. From the numerical results, it can be concluded that the disorder in the length of the periodic two-span beams will cause vibration localizations of the free and forced vibrations of the structure, and the vibration localization phenomenon will be more and more obvious when the length difference between the two sub-beams increases. Moreover, when the velocity feedback control is used, both the forced and the free vibrations will be suppressed. Meanwhile, the vibration behaviors of the two-span beam are tuned.展开更多
We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, unifor...We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, uniform distribution and high content of Ca Cl2, and exhibits high adsorption performance. The ammonia uptake and specific cooling power（SCP） at 5 min adsorption time can reach as high as 0.19 g·g^-1 and 793.9 W·kg^-1, respectively. The concept of utilizing the biomass materials and hygroscopic salts as raw materials for the preparation of adsorbents is of practical interest with respect to the potential quantity of biomass materials around the world, indicating that there would be a new market for biomass materials.Key words： biomass material; adsorption system; ammonia; calcium chloride; activated carbon展开更多
Activities of space materials science research in China have been continuously supported by two main national programs.One is the China Space Station(CSS)program since 1992,and the other is the Strategic Priority Prog...Activities of space materials science research in China have been continuously supported by two main national programs.One is the China Space Station(CSS)program since 1992,and the other is the Strategic Priority Program(SPP)on Space Science since 2011.In CSS plan in 2019,eleven space materials science experimental projects were officially approved for execution during the construction of the space station.In the SPP Phase Ⅱ launched in 2018,seven pre-research projects are deployed as the first batch in 2018,and one concept study project in 2019.These pre-research projects will be cultivated as candidates for future selection as space experiment projects on the recovery of scientific experimental satellites in the future.A new apparatus of electrostatic levitation system for ground-based research of space materials science and rapid solidification research has been developed under the support of the National Natural Science Foundation of China.In order to promote domestic academic activities and to enhance the advancement of space materials science in China,the Space Materials Science and Technology Division belong to the Chinese Materials Research Society was established in 2019.We also organized scientists to write five review papers on space materials science as a special topic published in the journal Scientia Sinica to provide valuable scientific and technical references for Chinese researchers.展开更多
Fusion technologies and materials researches made progress in the major three aspects in 2006, specially implemented the ITER agreement tasks of first wall （FW） plate fabrication qualification and shield bulk therma...Fusion technologies and materials researches made progress in the major three aspects in 2006, specially implemented the ITER agreement tasks of first wall （FW） plate fabrication qualification and shield bulk thermal-hydraulic analysis and design, studied on low activation fusion structure materials and High Z plasma facing materials, experimentally investigated on liquid metal blanket magneto-hydrodynamics effects and so on.展开更多
The flexible physical sensors have the advantage of pliability and extensibility and can be easily twisted or curved.The development of flexibility from rigidity has significantly increased the application situations ...The flexible physical sensors have the advantage of pliability and extensibility and can be easily twisted or curved.The development of flexibility from rigidity has significantly increased the application situations for sensors,especially in intelligent robots,tactile platforms,wearable medical sensors,bionic devices,and other fields.The research of membrane-based flexible physical sensors relies on the development of advanced materials and technologies,which have been derived from a wide range of applications.Various technical methods and principles have gradually matured according to the different applications and materials used.The first section of this review discusses membrane substrates and functional materials,summarizing the development of flexible physical sensors.According to the technical sensing principles,the review is concerned with the state of research on physical sensing platforms.Lastly,the difficulties and chances for the design of emerging membrane-based flexible physical sensors in the coming years are presented.展开更多
The uncontrollable dendrite growth of lithium anode and active material dissolution of transition metal oxides cathodes severely hinder the development of lithium metal batteries.An effective strategy to address these...The uncontrollable dendrite growth of lithium anode and active material dissolution of transition metal oxides cathodes severely hinder the development of lithium metal batteries.An effective strategy to address these issues is optimizing the separator to regulate ion transport and trap the lost active component.Herein,a crosslinked gelatin nonwoven(CGN)separator is elaborately fabricated through electrospinning and in-situ vapor phase crosslinking process to manipulate the dual electrode interface.Benefitting from the characteristic composition of gelatin,and porous structure of electrospun nonwoven,the CGN separator exhibits excellent interface wettability and low interface resistance,featuring a high Li^(+)transference number of 0.70 and high ionic conductivity of 3.75 m S/cm.As expected,the symmetrical Li/Li cells present stable cycling behavior for 1900 h at 0.5 mA/cm^(2)with low overpotential of 20 mV.The optimized LiMn_(2)O_(4)/Li cells deliver high reversible capacity of 103 m Ah/g as well as high capacityretention ratio of 83.7%after 100 cycles at 0.3 C,which can be effectively attributed to the strong interaction between CGN separator and Mn ions to prevent the loss of active Mn component.This study indicates the application potential of protein-based electrospun membrane for high-performance lithium metal batteries.展开更多
All-solid-state batteries(ASSBs)are a promising next-generation energy storage solution due to their high energy density and enhanced safety.To achieve this,specialized electrode designs are required to efficiently en...All-solid-state batteries(ASSBs)are a promising next-generation energy storage solution due to their high energy density and enhanced safety.To achieve this,specialized electrode designs are required to efficiently enhance interparticle lithium-ion transport between solid components.In particular,for active materials with high specific capacity,such as silicon,their volume expansion and shrinkage must be carefully controlled to maintain mechanical interface stability,which is crucial for effective lithium-ion transport in ASSBs.Herein,we propose a mechanical stress-tolerant all-solid-state graphite/silicon electrode design to ensure stable lithium-ion diffusion at the interface through morphology control of active material particles.Plate-type graphite with a high surface-area-to-volume ratio is used to maximize the dispersion of silicon within the electrode.The carefully designed electrode can accommodate the volume changes of silicon,ensuring stable capacity retention over cycles.Additionally,spherical graphite is shown to contribute to improved rate performance by providing an efficient lithium-ion diffusion pathway within the electrode.Therefore,the synergistic effect of our electrode structure offers balanced electrochemical performance,providing practical insights into the mechano-electrochemical interactions essential for designing highperformance all-solid-state electrodes.展开更多
The scintillating photonic glass has the great potential for medicine imaging,nuclear physics,highenergy physics,and national defense.However,the development of the candidate with the high density remains a significan...The scintillating photonic glass has the great potential for medicine imaging,nuclear physics,highenergy physics,and national defense.However,the development of the candidate with the high density remains a significant challenge.Herein,the superdense scintillating glasses derived from the Ce^(3+)-activated Lu_(2)O_(3)-SiO_(2)binary system were successfully fabricated by the strategy of contactless aerodynamic levitation heating under the N_(2)atmosphere.These glasses are colorless,optical homogeneous,and exhibit superdense density from 6.59 to 7.15 g/cm^(3),representing the highest density among the fast decay glass systems.The materials present excellent radiation-blocking ability,suitable emission wavelength,and fast response,indicating the promise for fast-eve nt X-ray detection.The micro radiation probe was fabricated by connecting the scintillating glass and the optical fiber.The practical application in remote radiation detection is demonstrated and it exhibits excellent linear response and high signalto-noise ratio.The results confirm that the fabricated superdense scintillating glass is promising for application in the field of high-energy radiation detection.展开更多
The activated nitrogen-enriched novel carbons (NENCs) were prepared by direct carbonization using polyaniline coating activated mesocarbon microbead composites as the precursor. Herein the influences of the carbonizat...The activated nitrogen-enriched novel carbons (NENCs) were prepared by direct carbonization using polyaniline coating activated mesocarbon microbead composites as the precursor. Herein the influences of the carbonization temperature on the structure and morphology of the NENCs samples were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 adsorption/desorption isotherm at 77 K. The electrochemical properties of the supercapacitors were characterized by cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), cycle life, leakage current and self-discharge measurements in 6 mol/L KOH solution. The results demonstrate that the NENC samples carbonized at 600 °C show the highest specific capacitance of 385 F/g at the current density of 1 A/g and the lowest ESR value (only 0.93?). Furthermore, the capacity retention ratio of the NENCs-600 supercapacitor is 92.8 % over 2500 cycles.展开更多
In response to a stimulus, a soft material deforms, and the deformation provides a function. We call such a material a soft active material （SAM）. This review focuses on one class of soft active materials： dielectr...In response to a stimulus, a soft material deforms, and the deformation provides a function. We call such a material a soft active material （SAM）. This review focuses on one class of soft active materials： dielectric elastomers. When a membrane of a dielectric elastomer is subject to a voltage through its thickness, the membrane reduces thickness and expands area, possibly straining over 100%. The dielectric elastomers are being developed as transducers for broad applications, including soft robots, adaptive optics, Braille displays, and electric generators. This paper reviews the theory of dielectric elastomers, developed within continuum mechanics and thermodynamics, and motivated by molecular pictures and empirical observations. The theory couples large deformation and electric potential, and describes nonlinear and nonequilibrium behavior, such as electromechanical instability and viscoelasticity. The theory enables the finite element method to simulate transducers of realistic configurations, predicts the efficiency of electromechanical energy conversion, and suggests alternative routes to achieve giant voltage-induced deformation. It is hoped that the theory will aid in the creation of materials and devices.展开更多
Polyvinyl alcohol （PVA）-sodium polyacrylate （PAAS）-KOH-H2O alkaline polymer electrolyte film with high ionic conductivity was prepared by a solution-casting method. Polymer Ni（OH）2/activated carbon （AC） hybrid...Polyvinyl alcohol （PVA）-sodium polyacrylate （PAAS）-KOH-H2O alkaline polymer electrolyte film with high ionic conductivity was prepared by a solution-casting method. Polymer Ni（OH）2/activated carbon （AC） hybrid supercapacitors with different electrode active material mass ratios （positive to negative） were fabricated using this alkaline polymer electrolyte, nickel hydroxide positive electrodes, and AC negative electrodes. Galvanostatic charge/ discharge and electrochemical impedance spectroscopy （EIS） methods were used to study the electrochemical performance of the capacitors, such as charge/discharge specific capacitance, rate charge/discharge ability, and charge/discharge cyclic stability. Experimental results showed that with the decreasing of active material mass ratio m（Ni（OH）2）/m（AC）, the charge/discharge specific capacitance increases, but the rate charge/discharge ability and the charge/discharge cyclic stability decrease.展开更多
Flexible lithium-ion batteries(LIBs)are critical for the development of next-generation smart electronics.Conversion reaction-based electrodes have been considered promising to construct high energy-density flexible L...Flexible lithium-ion batteries(LIBs)are critical for the development of next-generation smart electronics.Conversion reaction-based electrodes have been considered promising to construct high energy-density flexible LIBs,which satisfy the ever-increasing demand for practical use.However,these electrodes suffer from inferior lithium-storage performance and structural instability during deformation and long-term lithiation/delithiation.These are caused by the sluggish reaction kinetics of active-materials and the superposition of responsive strains originating from the large lithiation-induced stress and applied stress.Here,we propose a stress-release strategy through elastic responses of nested wrinkle texturing of graphene,to achieve high deformability while maintaining structural integrity upon prolonged cycles within high-capacity electrodes.The wrinkles endow the electrode with a robust and flexible network for effective stress release.The resulting electrode shows large reversible stretchability,along with excellent electrochemical performance including high specific capacity,high-rate capability and long-term cycling stability.This strategy offers a new way to obtain high-performance flexible electrodes and can be extended to other energy-storage devices.展开更多
Lithium-sulfur(Li-S)batteries have been regarded as the candidate for the next-generation energy storage system due to the high theoretical specific capacity(1675 m Ah/g), energy density(2600 Wh/kg)and the abundance o...Lithium-sulfur(Li-S)batteries have been regarded as the candidate for the next-generation energy storage system due to the high theoretical specific capacity(1675 m Ah/g), energy density(2600 Wh/kg)and the abundance of elemental sulfur, but the application of Li-S batteries is impeded by a series of problems. Recently, all-solid-state Li-S batteries(ASSLSBs) have drawn great attention because many drawbacks such as safety issues caused by metallic lithium anodes and organic liquid electrolytes can be overcome through the use of solid-state electrolytes(SEs). However, not only the problems brought by sulfur cathodes still exist, but more trouble arouses from the interfaces between SEs and cathodes, hampering the practical application of ASSLSBs. Therefore, in order to deal with the problems, enormous endeavors have been done on ASSLSB cathodes during the past few decades, including engineering of cathode active materials, cathode host materials, cathode binder materials and cathode structures. In this review, the electrochemical mechanism and existing problems of ASSLSBs are briefly introduced. Subsequently, the strategies for developing cathode materials and designing cathode structures are presented. Then there follows a brief discussion of SE problems and expectations, and finally, the challenges and perspectives of ASSLSBs are summarized.展开更多
The time-dependent electro-viscoelastic performance of a circular dielectric elastomer(DE) membrane actuator containing an inclusion is investigated in the context of the nonlinear theory for viscoelastic dielectrics....The time-dependent electro-viscoelastic performance of a circular dielectric elastomer(DE) membrane actuator containing an inclusion is investigated in the context of the nonlinear theory for viscoelastic dielectrics. The membrane, a key part of the actuator, is centrally attached to a rigid inclusion of the radius a, and then connected to a fixed rigid ring of the radius b. When subject to a pressure and a voltage, the membrane inflates into an out-of-plane shape and undergoes an inhomogeneous large deformation. The governing equations for the large deformation are derived by means of non-equilibrium thermodynamics, and viscoelasticity of the membrane is characterized by a rheological spring-dashpot model. In the simulation, effects of the pressure, the voltage, and design parameters on the electromechanical viscoelastic behaviors of the membrane are investigated. Evolutions of the considered variables and profiles of the deformed membrane are obtained numerically and illustrated graphically. The results show that electromechanical loadings and design parameters significantly influence the electro-viscoelastic behaviors of the membrane. The design parameters can be tailored to improve the performance of the membrane. The approach may provide guidelines in designing and optimizing such DE devices.展开更多
In order to increase the specific energy and specific power of a lead-acid battery, lead foam grid was prepared by electrodepositing Pb-Sn alloy on a copper foam substrate and used as negative current collector for a ...In order to increase the specific energy and specific power of a lead-acid battery, lead foam grid was prepared by electrodepositing Pb-Sn alloy on a copper foam substrate and used as negative current collector for a lead acid battery whose capacity was limited by the negative plate. Comparing the effect of the cast grid, under the same conditions, the mass of lead foam grid decreases by 35%, and the area of lead foam contacted with active material increases by about 20 times. Under 2 h rate discharge condition, with a high current （3 0 I2） e and low-temperature （-10 ℃, I2） discharge system, the lead foam grid markedly boosts the discharge performance of lead acid battery. It increases not only the negative electrode mass specific capacity by 27%,37% and 29%,but also the utilization efficiency of the negative active material by 5%. Compared with the negative electrode of cast grid, XRD and SEM results show that after 20 cycles at the state of charge, the sponge lead in the negative lead foam electrode has smaller crystals and less PbSO4 on its surface. Meanwhile, at the state of full discharge, the PbSO4 crystals are smaller and occur less on the surface of lead foam electrode. This indicates its active material reacts more uniformly.展开更多
文摘The electromagnetic properties of high temperature superconductors(HTS)are characterized with the explicit intent to improve their integration in electric power systems.A tape and a coil made of Bismuth Strontium Calcium Copper Oxide(BSCCO)are considered in the presence of electromagnetically active materials in order to mimic properly the electromagnetic environment typical of electrical machines.The characterization consists of the determining the critical current and the AC losses at different values of the frequency and the transport current.The effects induced by the proximity of the active materials are studied and some related experimental issues are analyzedc.
基金the financial support from the National Natural Science Foundation of China and the start-up projectthe Sichuan-University-Dazhou Joint project(00309053A2037)+1 种基金the Fundamental Research Funds for the Central Universitiespartially sponsored by the Double First-Class Construction Funds of Sichuan University。
文摘The microstructures on electrode level are crucial for battery performance, but the ambiguous understanding of both electrode microstructures and their structuring process causes critical challenges in controlling and evaluating the electrode quality during fabrication. In this review, analogous to the cell microenvironment well-known in biology, we introduce the concept of ‘‘active material microenvironment”(ME@AM)that is built by the ion/electron transport structures surrounding the AMs, for better understanding the significance of the electrode microstructures. Further, the scientific significance of electrode processing for electrode quality control is highlighted by its strong links to the structuring and quality control of ME@AM. Meanwhile, the roles of electrode rheology in both electrode structuring and structural characterizations involved in the entire electrode manufacturing process(i.e., slurry preparation, coating/printing/extrusion, drying and calendering) are specifically detailed. The advantages of electrode rheology testing on in-situ characterizations of the electrode qualities/structures are emphasized. This review provides a glimpse of the electrode rheology engaged in electrode manufacturing process and new insights into the understanding and effective regulation of electrode microstructures for future high-performance batteries.
文摘Recently we have studied the rare earth ion-selective electrodes with active materials of the func-tional polymers and found that the process chosen for the functional polymers had an effect on the propertiesof gadolinium ion selective electrode besides the effects of their structures.1.Effect of preparation process of the grafted polymers on the properties ofgadolinium ion selective electrodesThe electrode membranes which consist of functional polymers as active materials were prepared by re-action of gadolinium chloride with the radiation grafted clmer of acrlic acid and polystyrene of which
文摘In this paper,the functional polymeric active materials were prepared by the grafting copolymerization and their structure and properties were studied.The results show that the structure and properties of these ac- tive materials have the relative large effects on the properties of gadolinium ion selective electrodes.
基金supported by the New Materials Research Key Program of Tianjin(Grant No.18ZXJMTG00110).
文摘Sulfurized polyacrylonitrile(SPAN)has emerged as an excellent cathode material for lithium–sulfur batteries(LiSBs),and it addresses the shuttle effect through a solid‒solid reaction.However,the actual sulfur loadings in SPAN often remain below 40 wt%.Due to the susceptibility of polysulfides-to-nucleophilic reactions with electrolytes,achieving physical encapsulation of elemental sulfur is a challenging task.In this study,a free-standing cathode material with a high sulfur/selenium(S/Se)loading of 55 wt%was fabricated by introducing SeS_(x) into the unique lotus root-like pores of porous SeS_(x)PAN nanofiber membranes by electrospinning and a two-step heat treatment.Insoluble compounds were formed due to nucleophilic interactions between lithium polyselenosulfides(LiSeSx)and the electrolyte,which potently blocked the existing lotus root-like pores and facilitated the creation of a thin cathode–electrolyte interphase on the fiber surface.This dual functionality of LiSeS_(x) safeguarded the active material embedded within the porous structure.The SeS_(15)PAN cathode exhibited remarkable cycling stability with almost no degradation after 200 cycles at 0.2 C,along with a high discharge capacity of 580 mAh/g.This approach presents a solution for addressing the insufficient sulfur content in SPAN.
基金Project supported by the National Basic Research Program of China(973 Program)(No.2011CB711100)the National Natural Science Foundation of China(Nos.10672017 and11172084)
文摘The piezoelectric materials are used to investigate the active vibration control of ordered/disordered periodic two-span beams. The equation of motion of each sub-beam with piezoelectric patches is established based on Hamilton＇s principle with an assumed mode method. The velocity feedback control algorithm is used to design the controller. The free and forced vibration behaviors of the two-span beams with the piezoelectric actuators and sensors are analyzed. The vibration properties of the disordered two-span beams caused by misplacing the middle support are also researched. In addition, the effects of the length disorder degree on the vibration performances of the disordered beams are investigated. From the numerical results, it can be concluded that the disorder in the length of the periodic two-span beams will cause vibration localizations of the free and forced vibrations of the structure, and the vibration localization phenomenon will be more and more obvious when the length difference between the two sub-beams increases. Moreover, when the velocity feedback control is used, both the forced and the free vibrations will be suppressed. Meanwhile, the vibration behaviors of the two-span beam are tuned.
基金Funded by the National Natural Science Foundation of China(No.51106161)the National Hi-Tech Research and Development Program of China(No.2012AA053003)the Guangdong Province and Chinese Academy of Sciences Comprehensive Strategic Cooperation Projects(2012B091100263)
文摘We put forward a new and ingenious method for the preparation of a new adsorbent by soaking, carbonizing and activating the mixture of hygroscopic salt and biomass material. The new adsorbent has high porosity, uniform distribution and high content of Ca Cl2, and exhibits high adsorption performance. The ammonia uptake and specific cooling power（SCP） at 5 min adsorption time can reach as high as 0.19 g·g^-1 and 793.9 W·kg^-1, respectively. The concept of utilizing the biomass materials and hygroscopic salts as raw materials for the preparation of adsorbents is of practical interest with respect to the potential quantity of biomass materials around the world, indicating that there would be a new market for biomass materials.Key words： biomass material; adsorption system; ammonia; calcium chloride; activated carbon
基金Supports by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(XDA15013200,XDA15013700,XDA15013800,XDA15051200)the China’s Manned Space Station Project(TGJZ800-2-RW024)and the National Natural Science Foundation of China(51327901)。
文摘Activities of space materials science research in China have been continuously supported by two main national programs.One is the China Space Station(CSS)program since 1992,and the other is the Strategic Priority Program(SPP)on Space Science since 2011.In CSS plan in 2019,eleven space materials science experimental projects were officially approved for execution during the construction of the space station.In the SPP Phase Ⅱ launched in 2018,seven pre-research projects are deployed as the first batch in 2018,and one concept study project in 2019.These pre-research projects will be cultivated as candidates for future selection as space experiment projects on the recovery of scientific experimental satellites in the future.A new apparatus of electrostatic levitation system for ground-based research of space materials science and rapid solidification research has been developed under the support of the National Natural Science Foundation of China.In order to promote domestic academic activities and to enhance the advancement of space materials science in China,the Space Materials Science and Technology Division belong to the Chinese Materials Research Society was established in 2019.We also organized scientists to write five review papers on space materials science as a special topic published in the journal Scientia Sinica to provide valuable scientific and technical references for Chinese researchers.
文摘Fusion technologies and materials researches made progress in the major three aspects in 2006, specially implemented the ITER agreement tasks of first wall （FW） plate fabrication qualification and shield bulk thermal-hydraulic analysis and design, studied on low activation fusion structure materials and High Z plasma facing materials, experimentally investigated on liquid metal blanket magneto-hydrodynamics effects and so on.
基金supported by the National Natural Science Foundation of China(No.52403081)National Natural Science Foundation of China(No.52172126)+1 种基金Research Startup Fund of Changzhou University(ZMF24020055)Young Scientists Lifting Project of Changzhou and Jiangsu Province and Natural Science Foundation of Jiangsu Province of China(BX2023026)。
文摘The flexible physical sensors have the advantage of pliability and extensibility and can be easily twisted or curved.The development of flexibility from rigidity has significantly increased the application situations for sensors,especially in intelligent robots,tactile platforms,wearable medical sensors,bionic devices,and other fields.The research of membrane-based flexible physical sensors relies on the development of advanced materials and technologies,which have been derived from a wide range of applications.Various technical methods and principles have gradually matured according to the different applications and materials used.The first section of this review discusses membrane substrates and functional materials,summarizing the development of flexible physical sensors.According to the technical sensing principles,the review is concerned with the state of research on physical sensing platforms.Lastly,the difficulties and chances for the design of emerging membrane-based flexible physical sensors in the coming years are presented.
基金supported by National Natural Science Foundation of China(No.22309029)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515140011)+1 种基金Dongguan Social Development Technology Foundation(No.20231800907933)Collaborative Innovation Center of Marine Science and Technology of Hainan University(No.XTCX2022HYC14)。
文摘The uncontrollable dendrite growth of lithium anode and active material dissolution of transition metal oxides cathodes severely hinder the development of lithium metal batteries.An effective strategy to address these issues is optimizing the separator to regulate ion transport and trap the lost active component.Herein,a crosslinked gelatin nonwoven(CGN)separator is elaborately fabricated through electrospinning and in-situ vapor phase crosslinking process to manipulate the dual electrode interface.Benefitting from the characteristic composition of gelatin,and porous structure of electrospun nonwoven,the CGN separator exhibits excellent interface wettability and low interface resistance,featuring a high Li^(+)transference number of 0.70 and high ionic conductivity of 3.75 m S/cm.As expected,the symmetrical Li/Li cells present stable cycling behavior for 1900 h at 0.5 mA/cm^(2)with low overpotential of 20 mV.The optimized LiMn_(2)O_(4)/Li cells deliver high reversible capacity of 103 m Ah/g as well as high capacityretention ratio of 83.7%after 100 cycles at 0.3 C,which can be effectively attributed to the strong interaction between CGN separator and Mn ions to prevent the loss of active Mn component.This study indicates the application potential of protein-based electrospun membrane for high-performance lithium metal batteries.
基金supported by the National Research Council of Science&Technology(NST)grant by the Korea government(MSIT)(No.GTL24011-000)the National Research Foundation of Korea(NRF2022M3J1A1085396)the Technology Innovation Program(RS-2024-00445442)through the Korea Planning&Evaluation Institute of Industrial Technology(KEIT)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea).
文摘All-solid-state batteries(ASSBs)are a promising next-generation energy storage solution due to their high energy density and enhanced safety.To achieve this,specialized electrode designs are required to efficiently enhance interparticle lithium-ion transport between solid components.In particular,for active materials with high specific capacity,such as silicon,their volume expansion and shrinkage must be carefully controlled to maintain mechanical interface stability,which is crucial for effective lithium-ion transport in ASSBs.Herein,we propose a mechanical stress-tolerant all-solid-state graphite/silicon electrode design to ensure stable lithium-ion diffusion at the interface through morphology control of active material particles.Plate-type graphite with a high surface-area-to-volume ratio is used to maximize the dispersion of silicon within the electrode.The carefully designed electrode can accommodate the volume changes of silicon,ensuring stable capacity retention over cycles.Additionally,spherical graphite is shown to contribute to improved rate performance by providing an efficient lithium-ion diffusion pathway within the electrode.Therefore,the synergistic effect of our electrode structure offers balanced electrochemical performance,providing practical insights into the mechano-electrochemical interactions essential for designing highperformance all-solid-state electrodes.
基金supported by the National Science Fund for Distinguished Young Scholars(62125502)the National Natural Science Foundation of China(52302002,62305115)Guangdong Basic and Applied Basic Research Foundation(2024A1515011827)。
文摘The scintillating photonic glass has the great potential for medicine imaging,nuclear physics,highenergy physics,and national defense.However,the development of the candidate with the high density remains a significant challenge.Herein,the superdense scintillating glasses derived from the Ce^(3+)-activated Lu_(2)O_(3)-SiO_(2)binary system were successfully fabricated by the strategy of contactless aerodynamic levitation heating under the N_(2)atmosphere.These glasses are colorless,optical homogeneous,and exhibit superdense density from 6.59 to 7.15 g/cm^(3),representing the highest density among the fast decay glass systems.The materials present excellent radiation-blocking ability,suitable emission wavelength,and fast response,indicating the promise for fast-eve nt X-ray detection.The micro radiation probe was fabricated by connecting the scintillating glass and the optical fiber.The practical application in remote radiation detection is demonstrated and it exhibits excellent linear response and high signalto-noise ratio.The results confirm that the fabricated superdense scintillating glass is promising for application in the field of high-energy radiation detection.
基金Projects(51072173,51272221)supported by the National Natural Science Foundation of ChinaProject(20094301110005)supported by Specialized Research Fund for the Doctoral Program of Higher Education,ChinaProject(2013FJ4062)supported by Science and Technology Plan Foundation of Hunan Province,China
文摘The activated nitrogen-enriched novel carbons (NENCs) were prepared by direct carbonization using polyaniline coating activated mesocarbon microbead composites as the precursor. Herein the influences of the carbonization temperature on the structure and morphology of the NENCs samples were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 adsorption/desorption isotherm at 77 K. The electrochemical properties of the supercapacitors were characterized by cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), cycle life, leakage current and self-discharge measurements in 6 mol/L KOH solution. The results demonstrate that the NENC samples carbonized at 600 °C show the highest specific capacitance of 385 F/g at the current density of 1 A/g and the lowest ESR value (only 0.93?). Furthermore, the capacity retention ratio of the NENCs-600 supercapacitor is 92.8 % over 2500 cycles.
基金as a part of a research program on Soft Active Materials,supported at various times by NSF (CMMI-0800161, Large Deformation and Instability in Soft Active Materials)MURI (W911NF-04-1-0170, Design and Processing of Electret Structures+2 种基金 W911NF-09-1-0476, Innovative Design and Processing for Multi-Functional Adaptive Structural Materials)DARPA (W911NF-08-1-0143,ProgrammableMatterW911NF-10-1-0113, Cephalopod-Inspired Adaptive Photonic Systems)
文摘In response to a stimulus, a soft material deforms, and the deformation provides a function. We call such a material a soft active material （SAM）. This review focuses on one class of soft active materials： dielectric elastomers. When a membrane of a dielectric elastomer is subject to a voltage through its thickness, the membrane reduces thickness and expands area, possibly straining over 100%. The dielectric elastomers are being developed as transducers for broad applications, including soft robots, adaptive optics, Braille displays, and electric generators. This paper reviews the theory of dielectric elastomers, developed within continuum mechanics and thermodynamics, and motivated by molecular pictures and empirical observations. The theory couples large deformation and electric potential, and describes nonlinear and nonequilibrium behavior, such as electromechanical instability and viscoelasticity. The theory enables the finite element method to simulate transducers of realistic configurations, predicts the efficiency of electromechanical energy conversion, and suggests alternative routes to achieve giant voltage-induced deformation. It is hoped that the theory will aid in the creation of materials and devices.
基金Supported by Leading Academic Discipline Project of Shanghai Municipal Education Commission (J50102)
文摘Polyvinyl alcohol （PVA）-sodium polyacrylate （PAAS）-KOH-H2O alkaline polymer electrolyte film with high ionic conductivity was prepared by a solution-casting method. Polymer Ni（OH）2/activated carbon （AC） hybrid supercapacitors with different electrode active material mass ratios （positive to negative） were fabricated using this alkaline polymer electrolyte, nickel hydroxide positive electrodes, and AC negative electrodes. Galvanostatic charge/ discharge and electrochemical impedance spectroscopy （EIS） methods were used to study the electrochemical performance of the capacitors, such as charge/discharge specific capacitance, rate charge/discharge ability, and charge/discharge cyclic stability. Experimental results showed that with the decreasing of active material mass ratio m（Ni（OH）2）/m（AC）, the charge/discharge specific capacitance increases, but the rate charge/discharge ability and the charge/discharge cyclic stability decrease.
基金financial support from the National Natural Science Foundation of China(Nos.52020105010,51927803,51525206)the National Key R&D Program of China(2016YFA0200102 and 2016YFB0100100)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA22010602)the LiaoNing Revitalization Talents Program(No.XLYC1908015)。
文摘Flexible lithium-ion batteries(LIBs)are critical for the development of next-generation smart electronics.Conversion reaction-based electrodes have been considered promising to construct high energy-density flexible LIBs,which satisfy the ever-increasing demand for practical use.However,these electrodes suffer from inferior lithium-storage performance and structural instability during deformation and long-term lithiation/delithiation.These are caused by the sluggish reaction kinetics of active-materials and the superposition of responsive strains originating from the large lithiation-induced stress and applied stress.Here,we propose a stress-release strategy through elastic responses of nested wrinkle texturing of graphene,to achieve high deformability while maintaining structural integrity upon prolonged cycles within high-capacity electrodes.The wrinkles endow the electrode with a robust and flexible network for effective stress release.The resulting electrode shows large reversible stretchability,along with excellent electrochemical performance including high specific capacity,high-rate capability and long-term cycling stability.This strategy offers a new way to obtain high-performance flexible electrodes and can be extended to other energy-storage devices.
基金supported by the National Natural Science Foundation of China (Nos. 51874110 and 51604089)Natural Science Foundation of Heilongjiang Province (No. LH2021B011)Open Project of State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (No. QA202138)。
文摘Lithium-sulfur(Li-S)batteries have been regarded as the candidate for the next-generation energy storage system due to the high theoretical specific capacity(1675 m Ah/g), energy density(2600 Wh/kg)and the abundance of elemental sulfur, but the application of Li-S batteries is impeded by a series of problems. Recently, all-solid-state Li-S batteries(ASSLSBs) have drawn great attention because many drawbacks such as safety issues caused by metallic lithium anodes and organic liquid electrolytes can be overcome through the use of solid-state electrolytes(SEs). However, not only the problems brought by sulfur cathodes still exist, but more trouble arouses from the interfaces between SEs and cathodes, hampering the practical application of ASSLSBs. Therefore, in order to deal with the problems, enormous endeavors have been done on ASSLSB cathodes during the past few decades, including engineering of cathode active materials, cathode host materials, cathode binder materials and cathode structures. In this review, the electrochemical mechanism and existing problems of ASSLSBs are briefly introduced. Subsequently, the strategies for developing cathode materials and designing cathode structures are presented. Then there follows a brief discussion of SE problems and expectations, and finally, the challenges and perspectives of ASSLSBs are summarized.
基金Project supported by the National Natural Science Foundation of China(No.11372123)
文摘The time-dependent electro-viscoelastic performance of a circular dielectric elastomer(DE) membrane actuator containing an inclusion is investigated in the context of the nonlinear theory for viscoelastic dielectrics. The membrane, a key part of the actuator, is centrally attached to a rigid inclusion of the radius a, and then connected to a fixed rigid ring of the radius b. When subject to a pressure and a voltage, the membrane inflates into an out-of-plane shape and undergoes an inhomogeneous large deformation. The governing equations for the large deformation are derived by means of non-equilibrium thermodynamics, and viscoelasticity of the membrane is characterized by a rheological spring-dashpot model. In the simulation, effects of the pressure, the voltage, and design parameters on the electromechanical viscoelastic behaviors of the membrane are investigated. Evolutions of the considered variables and profiles of the deformed membrane are obtained numerically and illustrated graphically. The results show that electromechanical loadings and design parameters significantly influence the electro-viscoelastic behaviors of the membrane. The design parameters can be tailored to improve the performance of the membrane. The approach may provide guidelines in designing and optimizing such DE devices.
文摘In order to increase the specific energy and specific power of a lead-acid battery, lead foam grid was prepared by electrodepositing Pb-Sn alloy on a copper foam substrate and used as negative current collector for a lead acid battery whose capacity was limited by the negative plate. Comparing the effect of the cast grid, under the same conditions, the mass of lead foam grid decreases by 35%, and the area of lead foam contacted with active material increases by about 20 times. Under 2 h rate discharge condition, with a high current （3 0 I2） e and low-temperature （-10 ℃, I2） discharge system, the lead foam grid markedly boosts the discharge performance of lead acid battery. It increases not only the negative electrode mass specific capacity by 27%,37% and 29%,but also the utilization efficiency of the negative active material by 5%. Compared with the negative electrode of cast grid, XRD and SEM results show that after 20 cycles at the state of charge, the sponge lead in the negative lead foam electrode has smaller crystals and less PbSO4 on its surface. Meanwhile, at the state of full discharge, the PbSO4 crystals are smaller and occur less on the surface of lead foam electrode. This indicates its active material reacts more uniformly.
