In this work,an acoustic topology optimizationmethod for structural surface design covered by porous materials is proposed.The analysis of acoustic problems is performed using the isogeometric boundary elementmethod.T...In this work,an acoustic topology optimizationmethod for structural surface design covered by porous materials is proposed.The analysis of acoustic problems is performed using the isogeometric boundary elementmethod.Taking the element density of porousmaterials as the design variable,the volume of porousmaterials as the constraint,and the minimum sound pressure or maximum scattered sound power as the design goal,the topology optimization is carried out by solid isotropic material with penalization(SIMP)method.To get a limpid 0–1 distribution,a smoothing Heaviside-like function is proposed.To obtain the gradient value of the objective function,a sensitivity analysis method based on the adjoint variable method(AVM)is proposed.To find the optimal solution,the optimization problems are solved by the method of moving asymptotes(MMA)based on gradient information.Numerical examples verify the effectiveness of the proposed topology optimization method in the optimization process of two-dimensional acoustic problems.Furthermore,the optimal distribution of sound-absorbingmaterials is highly frequency-dependent and usually needs to be performed within a frequency band.展开更多
Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries.Among them,poly(diallyl tetrasulfide)(PDATtS)deli...Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries.Among them,poly(diallyl tetrasulfide)(PDATtS)delivered a high capacity of 700 mAh g^(-1),stable capacity retention of 85%after 300 cycles,high areal capacity~4 m Ah cm^(-2) for electrode with up to 10.3 mg cm^(-2) loading.New insight into the reaction mechanism of PDATtS electrode that radicals arisen from the homolytic cleavage of S-S bond in PDATtS reacted with Li+to generate thiolates(RSLi)and insoluble lithium sulfides(Li_(2)S)or lithium disulfide(Li_(2)S_(2))was clearly verified by in-situ UV/Vis spectroscopy,nuclear magnetic resonance(NMR)studies and density-functional theory(DFT)calculations.Therefore,based on the unique reaction mechanism,problems of rapid capacity fading due to the formation of soluble polysulfide intermediates and their serious shuttle effect in conventional lithium-sulfur(Li-S)batteries was totally avoided,realizing the dendrite-free lithium sulfur batteries.This study sets new trends for avenues of further research to advance Li-S battery technologies.展开更多
The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables al...The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables all the discharging in termediates to exist in an amorphous state without long-range order,promoti ng the substantial conversion of discharging intermediates and enhancing Li-S batteries'performance at low temperatures greatly.This cathode material exhibits excellent performance both at room and low temperatures.Even under an extremely low temperature(-40℃),the discharge capacity can remain 67% of that at room temperature.Besides,in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during discharge.Li_(2)S_(6) and Li_(2)S_(3) are the primary discharging intermediates that are quite different from conventional Li-S batteries.These results provide a new directi on for a broader range of applications of Li-S batteries.展开更多
High-entropy materials are mainly composed of high-entropy alloys(HEAs)and their derivates.Among them,HEAs account for a big part.As a new kind of alloy,they are now arousing great interests because of their high mech...High-entropy materials are mainly composed of high-entropy alloys(HEAs)and their derivates.Among them,HEAs account for a big part.As a new kind of alloy,they are now arousing great interests because of their high mechanical strength,extraordinary fracture toughness,corrosion resistance compared with traditional alloys.These characteristics allow the use of HEAs in various fields,including mechanical manufacturing,heat-resistant,radiation-resistant,corrosion-resistant,wear-resistant coatings,energy storage,heterocatalysis,etc.In order to promote the extensive application of HEAs,it is of significance to realize their rational design and preparation.In this paper,a systematic review focusing on the rational design and fabrication of nanosized HEAs is given.The design principles of how to match different elements in HEAs and the premise for the formation of single-phase solid solution HEAs are first illustrated.Computation methods for the prediction of formation conditions and properties of HEAs are also in discussion.Then,a detailed description and comparison of the synthesis methods of HEAs and their derivate,as well as their growing mechanism under various synthetic environments is provided.The commonly used characterization methods for the detection of HEAs,along with the typical cases of the application of HEAs in industrial materials,energy storage materials and catalytic materials are also included.Finally,the challenges and perspectives in the design and synthesis of HEAs would be proposed.We hope this review will give guidance for the future development of HEAs materials.展开更多
基金sponsored by Natural Science Foundation of Henan under Grant No.222300420498.
文摘In this work,an acoustic topology optimizationmethod for structural surface design covered by porous materials is proposed.The analysis of acoustic problems is performed using the isogeometric boundary elementmethod.Taking the element density of porousmaterials as the design variable,the volume of porousmaterials as the constraint,and the minimum sound pressure or maximum scattered sound power as the design goal,the topology optimization is carried out by solid isotropic material with penalization(SIMP)method.To get a limpid 0–1 distribution,a smoothing Heaviside-like function is proposed.To obtain the gradient value of the objective function,a sensitivity analysis method based on the adjoint variable method(AVM)is proposed.To find the optimal solution,the optimization problems are solved by the method of moving asymptotes(MMA)based on gradient information.Numerical examples verify the effectiveness of the proposed topology optimization method in the optimization process of two-dimensional acoustic problems.Furthermore,the optimal distribution of sound-absorbingmaterials is highly frequency-dependent and usually needs to be performed within a frequency band.
基金support from the National Natural Science Foundations of China(grants 51622208,21703149,and 51872193)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries.Among them,poly(diallyl tetrasulfide)(PDATtS)delivered a high capacity of 700 mAh g^(-1),stable capacity retention of 85%after 300 cycles,high areal capacity~4 m Ah cm^(-2) for electrode with up to 10.3 mg cm^(-2) loading.New insight into the reaction mechanism of PDATtS electrode that radicals arisen from the homolytic cleavage of S-S bond in PDATtS reacted with Li+to generate thiolates(RSLi)and insoluble lithium sulfides(Li_(2)S)or lithium disulfide(Li_(2)S_(2))was clearly verified by in-situ UV/Vis spectroscopy,nuclear magnetic resonance(NMR)studies and density-functional theory(DFT)calculations.Therefore,based on the unique reaction mechanism,problems of rapid capacity fading due to the formation of soluble polysulfide intermediates and their serious shuttle effect in conventional lithium-sulfur(Li-S)batteries was totally avoided,realizing the dendrite-free lithium sulfur batteries.This study sets new trends for avenues of further research to advance Li-S battery technologies.
基金support from the National Natural Science Foundations of China (grants 52071226 and 51872193)the Natural Science Foundations of Jiangsu Province (BE2020003-3 and BK20201171)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
文摘The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables all the discharging in termediates to exist in an amorphous state without long-range order,promoti ng the substantial conversion of discharging intermediates and enhancing Li-S batteries'performance at low temperatures greatly.This cathode material exhibits excellent performance both at room and low temperatures.Even under an extremely low temperature(-40℃),the discharge capacity can remain 67% of that at room temperature.Besides,in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during discharge.Li_(2)S_(6) and Li_(2)S_(3) are the primary discharging intermediates that are quite different from conventional Li-S batteries.These results provide a new directi on for a broader range of applications of Li-S batteries.
基金the National Natural Science Foundation of China(Nos.21703149,51872193,21938006,and 5192500409)the National Key Research&Development Program of China(No.2020YFC1808401)+1 种基金Cutting-Edge Technology Basic Research Project of Jiangsu(No.BK20202012)the project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘High-entropy materials are mainly composed of high-entropy alloys(HEAs)and their derivates.Among them,HEAs account for a big part.As a new kind of alloy,they are now arousing great interests because of their high mechanical strength,extraordinary fracture toughness,corrosion resistance compared with traditional alloys.These characteristics allow the use of HEAs in various fields,including mechanical manufacturing,heat-resistant,radiation-resistant,corrosion-resistant,wear-resistant coatings,energy storage,heterocatalysis,etc.In order to promote the extensive application of HEAs,it is of significance to realize their rational design and preparation.In this paper,a systematic review focusing on the rational design and fabrication of nanosized HEAs is given.The design principles of how to match different elements in HEAs and the premise for the formation of single-phase solid solution HEAs are first illustrated.Computation methods for the prediction of formation conditions and properties of HEAs are also in discussion.Then,a detailed description and comparison of the synthesis methods of HEAs and their derivate,as well as their growing mechanism under various synthetic environments is provided.The commonly used characterization methods for the detection of HEAs,along with the typical cases of the application of HEAs in industrial materials,energy storage materials and catalytic materials are also included.Finally,the challenges and perspectives in the design and synthesis of HEAs would be proposed.We hope this review will give guidance for the future development of HEAs materials.
基金supported by the National Natural Science Foundation of China(22078213,21938006,51973148,and 21776190)the National Key R&D Program of China(2020YFC1808401)+1 种基金the Cutting-Edge Technology Basic Research Project of Jiangsu(BK20202012)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。