To achieve the controllable release of energy of nitrocellulose-based propellants,this paper combines the cellulose-based nanocomposites aqueous coating(Surelease®-NC)with fluidized bed coating equipment to succe...To achieve the controllable release of energy of nitrocellulose-based propellants,this paper combines the cellulose-based nanocomposites aqueous coating(Surelease®-NC)with fluidized bed coating equipment to successfully prepare the coated spherical propellant for the first time.The effects of fluidized bed coating temperature,air velocity,flow speed and atomization pressure on the adhesion rate,coating integrity and coating uniformity of the coated spherical propellant were investigated,and the preparation of coated spherical propellant with homogeneous size and structural integrity was achieved for the first time.The microscopic morphology,chemical structure,water vapor adsorption behavior,combustion performance,and ageing resistance property of the coated spherical propellant were systematically investigated by,Fourier transforms infrared spectroscopy(FTIR),Micro confocal raman spectrometer,field scanning electron microscopy(SEM),dynamic vapor adsorption techniques,and closed bomb test,confirming the surface core-shell structure and the tightly bonded interfacial structure of coated spherical propellant.Meanwhile,the coated spherical propellant has good hygroscopic,excellent progressive burning and long storage stability.展开更多
Concentration distribution of the deterrent in single-base propellant during the process of firing plays an important role in the ballistic properties of gun propellant in weapons. However, the diffusion coefficient c...Concentration distribution of the deterrent in single-base propellant during the process of firing plays an important role in the ballistic properties of gun propellant in weapons. However, the diffusion coefficient calculated by molecular dynamics(MD) simulation is 6 orders of magnitude larger than the experimental values. Meanwhile, few simple and comprehensive theoretical models can explain the phenomenon and accurately predict the concentration distribution of the propellant. Herein, an onion model combining with MD simulation and finite element method of diffusion in propellants is introduced to bridge the gap between the experiments and simulations, and correctly predict the concentration distribution of deterrent. Furthermore, a new time scale is found to characterize the diffusion process. Finally, the time-and position-depended concentration distributions of dibutyl phthalate in nitrocellulose are measured by Raman spectroscopy to verify the correctness of the onion model. This work not only provides guidance for the design of the deterrent, but could be also extended to the diffusion of small molecules in polymer with different crystallinity.展开更多
The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathod...The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathode catalysts with high activity and stability is crucial to overcome the terrible issues at high current density.Herein,we report a surface engineering strategy to adjust the surface electron structure of boron(B)‐doped PtNi nanoalloy on carbon nanotubes(PtNiB@CNTs)as an efficient bifunctional cathodic catalyst for high‐rate and long‐life Li‐O2 batteries.Notably,the Li‐O2 batteries assembled with as‐prepared PtNiB@CNT catalyst exhibit ultrahigh discharge capacity of 20510 mA·h/g and extremely low overpotential of 0.48 V at a high current density of 1000 mA/g,both of which outperform the most reported Pt‐based catalysts recently.Meanwhile,our Li‐O2 batteries offer excellent rate capability and ultra‐long cycling life of up to 210 cycles at 1000 mA/g under a fixed capacity of 1000 mA·h/g,which is two times longer than those of Pt@CNTs and PtNi@CNTs.Furthermore,it is revealed that surface engineering of PtNi nanoalloy via B doping can efficiently tailor the electron structure of nanoalloy and optimize the adsorption of oxygen species,consequently delivering excellent Li‐O2 battery performance.Therefore,this strategy of regulating the nanoalloy by doping nonmetallic elements will pave an avenue for the design of high‐performance catalysts for metal‐oxygen batteries.展开更多
This work presents a brief introduction on three kinds of newly developed Nd^(3+)-doped laser glasses in Shanghai Institute of Optics and Fine Mechanics(SIOM), China. Two Nd^(3+)-doped phosphate glasses with lower the...This work presents a brief introduction on three kinds of newly developed Nd^(3+)-doped laser glasses in Shanghai Institute of Optics and Fine Mechanics(SIOM), China. Two Nd^(3+)-doped phosphate glasses with lower thermal expansion coefficient and thermal shock resistance 4 times higher than that of N31 glass are developed for laser processing.Nd:Silicate and Nd:Aluminate glasses with peak emission wavelength at 1061 and 1065 nm, effective emission bandwidth of 34 and 50 nm, respectively, are developed for Exawatt-class laser system application. Fluorophosphate glasses with low nonlinear refractive index(n_2=0.6–0.86) and long fluorescence lifetime(430–510 μs) are investigated for the purpose of decreasing B integral in high-power laser system. The properties of all these glasses are presented and compared with those of commercial neodymium laser glasses.展开更多
A highly porous nitrogen-doped carbon sphere(NPC)electrocatalyst was prepared through the carbonization of biomass carbon spheres mixed with urea and zinc chloride in N_(2) atmosphere.The sample carbonized at.1000℃ d...A highly porous nitrogen-doped carbon sphere(NPC)electrocatalyst was prepared through the carbonization of biomass carbon spheres mixed with urea and zinc chloride in N_(2) atmosphere.The sample carbonized at.1000℃ demonstrates a superior oxygen reduction reaction(ORR)performance over the Pt/C electrocatalyst,while its contents of pyridinic nitrogen and graphitic nitrogen are the lowest among samples synthesized at the same or lower carbonization temperatures.This unusual result is explained by a space confinement effect from the microporous and mesoporous structures in the microflakes,which induces the further reduction of peroxide ions or other oxygen species produced in the first step reduction to water to have the preferred overall four electron reduction ORR process.This work demonstrates that in addition to the amount or species of its aptive sites,the space confinement can be a new approach to enhance the ORR performance of precious-metal-free,nitrogen-doped carbon electrocatalysts.展开更多
Lithium-selenium(Li-Se)batteries have attracted ever-increasing attention owing to high volumetric capacity comparable to lithium-sulfur batteries and excellent electronic conductivity of Se.However,unsatisfactory ene...Lithium-selenium(Li-Se)batteries have attracted ever-increasing attention owing to high volumetric capacity comparable to lithium-sulfur batteries and excellent electronic conductivity of Se.However,unsatisfactory energy density and cycling life of Li-Se batteries mainly caused by low utilization of Se and shuttle effect of polyselenides(PSes)seriously prevent their commercial applica-tions.Herein,this work systematically reviews the recent advances of the state-of-the-art cathodes and interlayers in high-performance Li-Se batteries.First,the fundamental chemistries of Li-Se batteries are introduced in terms of var-ious Se precursors and electrochemical behaviors.Second,the main strategies in cathodes and interlayers for addressing poor conductivity of Se and shuttle effects of PSes are summarized as three-dimensional conductive skeletons for Se,physical confinement of Se,chemisorption and catalytic conversion of PSes,and free-standing interlayers and interlayers on separators.Further,the synthesis strategies and enhanced electrochemical performance are specially exemplified to highlight the possible enlightenments for constructing advanced cathodes and interlayers.Finally,the future challenges and perspectives of advanced cathodes and interlayers in high-performance Li-Se batteries are briefly discussed.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.22005143)Young Elite Scientists Sponsorship Program by CAST (Grant No.2022QNRC001)。
文摘To achieve the controllable release of energy of nitrocellulose-based propellants,this paper combines the cellulose-based nanocomposites aqueous coating(Surelease®-NC)with fluidized bed coating equipment to successfully prepare the coated spherical propellant for the first time.The effects of fluidized bed coating temperature,air velocity,flow speed and atomization pressure on the adhesion rate,coating integrity and coating uniformity of the coated spherical propellant were investigated,and the preparation of coated spherical propellant with homogeneous size and structural integrity was achieved for the first time.The microscopic morphology,chemical structure,water vapor adsorption behavior,combustion performance,and ageing resistance property of the coated spherical propellant were systematically investigated by,Fourier transforms infrared spectroscopy(FTIR),Micro confocal raman spectrometer,field scanning electron microscopy(SEM),dynamic vapor adsorption techniques,and closed bomb test,confirming the surface core-shell structure and the tightly bonded interfacial structure of coated spherical propellant.Meanwhile,the coated spherical propellant has good hygroscopic,excellent progressive burning and long storage stability.
基金sponsored by the National Natural Science Foundation of China (91834301, 22078088, 22005143)the National Natural Science Foundation of China for Innovative Research Groups (51621002)。
文摘Concentration distribution of the deterrent in single-base propellant during the process of firing plays an important role in the ballistic properties of gun propellant in weapons. However, the diffusion coefficient calculated by molecular dynamics(MD) simulation is 6 orders of magnitude larger than the experimental values. Meanwhile, few simple and comprehensive theoretical models can explain the phenomenon and accurately predict the concentration distribution of the propellant. Herein, an onion model combining with MD simulation and finite element method of diffusion in propellants is introduced to bridge the gap between the experiments and simulations, and correctly predict the concentration distribution of deterrent. Furthermore, a new time scale is found to characterize the diffusion process. Finally, the time-and position-depended concentration distributions of dibutyl phthalate in nitrocellulose are measured by Raman spectroscopy to verify the correctness of the onion model. This work not only provides guidance for the design of the deterrent, but could be also extended to the diffusion of small molecules in polymer with different crystallinity.
基金中国博士后科学基金(2021M693125)大连市高层次人才创新支持计划(2019RT09)+1 种基金中国科学院洁净能源创新研究院合作基金(DNL202016,DNL202019)中国科学院洁净能源创新研究院-榆林学院联合基金(YLU-DNL Fund 2021002,YLU-DNL Fund 2021009).
基金supported by the National Natural Science Foundation of China(Nos.22125903 and 51872283)Dalian Innovation Support Plan for High Level Talents(No.2019RT09)+2 种基金Dalian National Laboratory for Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(Nos.DNL201912,DNL201915,DNL202016,and DNL202019)DICP(No.DICP I2020032)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(Nos.YLU‐DNL Fund 2021002 and YLU‐DNL 2021009).
文摘The realization of high‐efficiency,reversible,stable,and safe Li‐O2 batteries is severely hindered by the large overpotential and side reactions,especially at high rate conditions.Therefore,rational design of cathode catalysts with high activity and stability is crucial to overcome the terrible issues at high current density.Herein,we report a surface engineering strategy to adjust the surface electron structure of boron(B)‐doped PtNi nanoalloy on carbon nanotubes(PtNiB@CNTs)as an efficient bifunctional cathodic catalyst for high‐rate and long‐life Li‐O2 batteries.Notably,the Li‐O2 batteries assembled with as‐prepared PtNiB@CNT catalyst exhibit ultrahigh discharge capacity of 20510 mA·h/g and extremely low overpotential of 0.48 V at a high current density of 1000 mA/g,both of which outperform the most reported Pt‐based catalysts recently.Meanwhile,our Li‐O2 batteries offer excellent rate capability and ultra‐long cycling life of up to 210 cycles at 1000 mA/g under a fixed capacity of 1000 mA·h/g,which is two times longer than those of Pt@CNTs and PtNi@CNTs.Furthermore,it is revealed that surface engineering of PtNi nanoalloy via B doping can efficiently tailor the electron structure of nanoalloy and optimize the adsorption of oxygen species,consequently delivering excellent Li‐O2 battery performance.Therefore,this strategy of regulating the nanoalloy by doping nonmetallic elements will pave an avenue for the design of high‐performance catalysts for metal‐oxygen batteries.
文摘This work presents a brief introduction on three kinds of newly developed Nd^(3+)-doped laser glasses in Shanghai Institute of Optics and Fine Mechanics(SIOM), China. Two Nd^(3+)-doped phosphate glasses with lower thermal expansion coefficient and thermal shock resistance 4 times higher than that of N31 glass are developed for laser processing.Nd:Silicate and Nd:Aluminate glasses with peak emission wavelength at 1061 and 1065 nm, effective emission bandwidth of 34 and 50 nm, respectively, are developed for Exawatt-class laser system application. Fluorophosphate glasses with low nonlinear refractive index(n_2=0.6–0.86) and long fluorescence lifetime(430–510 μs) are investigated for the purpose of decreasing B integral in high-power laser system. The properties of all these glasses are presented and compared with those of commercial neodymium laser glasses.
基金supported by the National Natural Science Foundation of China(Grant Nos.51672283 and 51902271)the Fundamental Research Funds for the Central Universities(Grant Nos.A1920502051907-15,2682020CX07,and 2682020CX08)+3 种基金Sichuan Science and Technology Program(Grant Nos.2020YJ0259 and 2020YJ0072)Shandong Provincial Natural Science Foundation(Grant No.ZR2019MEM045)Joint Fund between Shenyang National Laboratory for Materials Science and State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals(Grant No.18LHPY009)Liaoning Baiqianwan Talents Program.
文摘A highly porous nitrogen-doped carbon sphere(NPC)electrocatalyst was prepared through the carbonization of biomass carbon spheres mixed with urea and zinc chloride in N_(2) atmosphere.The sample carbonized at.1000℃ demonstrates a superior oxygen reduction reaction(ORR)performance over the Pt/C electrocatalyst,while its contents of pyridinic nitrogen and graphitic nitrogen are the lowest among samples synthesized at the same or lower carbonization temperatures.This unusual result is explained by a space confinement effect from the microporous and mesoporous structures in the microflakes,which induces the further reduction of peroxide ions or other oxygen species produced in the first step reduction to water to have the preferred overall four electron reduction ORR process.This work demonstrates that in addition to the amount or species of its aptive sites,the space confinement can be a new approach to enhance the ORR performance of precious-metal-free,nitrogen-doped carbon electrocatalysts.
基金National Key R&D Program of China,Grant/Award Numbers:2016YFB0100100,2016YFA0200200National Natural Sci-ence Foundation of China,Grant/Award Numbers:51872283,22075279,21805273,22005297,22005298+6 种基金Natural Science Foundation of Liaoning Province,Grant/Award Number:2020-MS-095Liao Ning Revitalization Talents Program,Grant/Award Numbers:XLYC1807153,XLYC2007129Dalian Innovation Support Plan for High Level Talents,Grant/Award Number:2019RT09DNL Coopera-tion Fund,Grant/Award Numbers:DNL201912,DNL201915,DNL202016,DNL202019DICP,Grant/Award Num-bers:ZZBS201708,ZZBS201802,I2020032Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy,Grant/Award Number:2021002Fundamental Research Funds for the Cen-tral Universities of China,Grant/Award Number:N2105008。
文摘Lithium-selenium(Li-Se)batteries have attracted ever-increasing attention owing to high volumetric capacity comparable to lithium-sulfur batteries and excellent electronic conductivity of Se.However,unsatisfactory energy density and cycling life of Li-Se batteries mainly caused by low utilization of Se and shuttle effect of polyselenides(PSes)seriously prevent their commercial applica-tions.Herein,this work systematically reviews the recent advances of the state-of-the-art cathodes and interlayers in high-performance Li-Se batteries.First,the fundamental chemistries of Li-Se batteries are introduced in terms of var-ious Se precursors and electrochemical behaviors.Second,the main strategies in cathodes and interlayers for addressing poor conductivity of Se and shuttle effects of PSes are summarized as three-dimensional conductive skeletons for Se,physical confinement of Se,chemisorption and catalytic conversion of PSes,and free-standing interlayers and interlayers on separators.Further,the synthesis strategies and enhanced electrochemical performance are specially exemplified to highlight the possible enlightenments for constructing advanced cathodes and interlayers.Finally,the future challenges and perspectives of advanced cathodes and interlayers in high-performance Li-Se batteries are briefly discussed.
