The molar mass distribution of SSO in the first generation derived from the hydrolytic condensation oftwo trialkoxysilanes, [ 3- ( Methacryloxy ) propyl ] trimethoxysilane ( MPMS ) and vinyltrimethoxysilane ( VMS ) ,a...The molar mass distribution of SSO in the first generation derived from the hydrolytic condensation oftwo trialkoxysilanes, [ 3- ( Methacryloxy ) propyl ] trimethoxysilane ( MPMS ) and vinyltrimethoxysilane ( VMS ) ,are determined by UV-MALDI-TOF MS. The comparisons of theoretical masses with experimental masses arecalculated using the proposed compounds, which are assigned to formulas Tn (OH)m, Tn (OMe)y orTn(OH)x(OMe)y[T=RSiO1.5 (x+y)/2n, R=--(CH2)3OOCCH(CH3)CH2 and--CHCH2]. Both theproposed cage and ladder structures of SSO derived from similar sol-gel process of monomers are illustrated. Thecauses for the difference in structures between SSO M and SSO V is discussed as well.展开更多
Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accident...Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.展开更多
Lithium–sulfur(Li–S)batteries have been becoming a new generation of secondary batteries due to their high theoretical energy density.Regarding sulfur-based cathodes,they not only help to strengthen the utilization ...Lithium–sulfur(Li–S)batteries have been becoming a new generation of secondary batteries due to their high theoretical energy density.Regarding sulfur-based cathodes,they not only help to strengthen the utilization of sulfur,but also effectively immobilize polysulfides to alleviate their dissolution and diffusion.Herein,a new confinement strategy is initiated by a distinctive sulfur scaffold,namely nitrogen doped gra phitic ladder-structured carbon nanotubes(NGLCNTs)loaded with appropriate amount of metallic cobalt nanoparticles.Benefiting from both the unique graphitic ladder-structure and metallic cobalt nano particles in the nitrogen doped carbon nanotubes,the NGLCNTs host not only promotes ion transfer and electron transmission during the redox reactions from higher-order polysulfides to Li_(2)S_(2)/Li_(2)S,but also effciently restricts the outward diffusion and dissolution of polysulfides as well as benefits the nucleation and growth of Li_(2)S.As a result,the NGLCNTs/S cathode has successfully overcome the crucial issues,and it exhibits greatly enhanced electrochemical performances with excellent rate capabilities of up to 8C and long term cycling life of over 500 cycles.展开更多
Few spin-crossover materials with a 1D ladder-type structure have been reported.Previously,[Fe(Mebpt){Au(CN)_(2)}]·H_(2)O(MebptH=3-(5-methyl-2-pyridyl)-5-(2-pyridyl)-1,2,4-triazole)was made and shown to display g...Few spin-crossover materials with a 1D ladder-type structure have been reported.Previously,[Fe(Mebpt){Au(CN)_(2)}]·H_(2)O(MebptH=3-(5-methyl-2-pyridyl)-5-(2-pyridyl)-1,2,4-triazole)was made and shown to display gradual spin-crossover behaviour.In the current work,a new 1D iron(Ⅱ)ladder-type compound,[Fe(bpt){Au(CN)_(2)}](bptH=3-(2-pyridyl)-5-(2-pyridyl)-1,2,4-triazole),was produced and showed enhanced spin-crossover behavior.It showed an abrupt spin transition above room temperature with a 3 K hysteresis(T_(1/2)↓=335 K and T_(1/2)↑=338 K).The origin of its enhanced spin-crossover could be ascribed to a greater influence of supramolecular interactions over the electronic substituent effect.展开更多
基金Sponsored by the Foundation of Department of Science and Technology of Heilongjiang Province
文摘The molar mass distribution of SSO in the first generation derived from the hydrolytic condensation oftwo trialkoxysilanes, [ 3- ( Methacryloxy ) propyl ] trimethoxysilane ( MPMS ) and vinyltrimethoxysilane ( VMS ) ,are determined by UV-MALDI-TOF MS. The comparisons of theoretical masses with experimental masses arecalculated using the proposed compounds, which are assigned to formulas Tn (OH)m, Tn (OMe)y orTn(OH)x(OMe)y[T=RSiO1.5 (x+y)/2n, R=--(CH2)3OOCCH(CH3)CH2 and--CHCH2]. Both theproposed cage and ladder structures of SSO derived from similar sol-gel process of monomers are illustrated. Thecauses for the difference in structures between SSO M and SSO V is discussed as well.
基金supported in part by the National Natural Science Foundation of China(No.22075146)。
文摘Nitrocellulose,or cellulose nitrate,has received considerable interest due to its various applications,such as propellants,coating agents and gas generators.However,its high mechanical sensitivity caused many accidents during its storage and usage in ammunition.In this work,two kinds of insensitive step ladderstructured nitrocellulose(LNC)with different nitrogen contents were synthesized.The products were characterized by FT-IR,Raman,XRD,SEM,elemental analysis,TGA,DSC,accelerating rate calorimeter analysis(ARC),and drop weight test to study their molecular structure,thermal characteristics and desensitization performance.Compared with raw nitrocellulose,LNC has a sharper exothermic peak in the DSC and ARC curves.The H50values of the two kinds of LNC increased from 25.76 to 30.01 cm for low nitrogen content and from 18.02 to 21.84 cm for high nitrogen content,respectively.The results show that the ladder-structure of LNC which provides regular molecular arrangement and a soft buffer made with polyethylene glycol could affect the energy releasing process of LNC and reduce the sensitivity of LNC.Insensitive LNC provides an alternative to be used as a binder in insensitive propellants formulation.
基金supports pro vided by the National Natural Science Foundation of China(21971145)the Taishan Scholar Project Foundation of Shandong Province(ts20190908 and ts201511004)+1 种基金the Natural Science Foundation of Shandong Province(ZR2019MB024)the Young Scholars Program of Shandong University(2017WLJH15).
文摘Lithium–sulfur(Li–S)batteries have been becoming a new generation of secondary batteries due to their high theoretical energy density.Regarding sulfur-based cathodes,they not only help to strengthen the utilization of sulfur,but also effectively immobilize polysulfides to alleviate their dissolution and diffusion.Herein,a new confinement strategy is initiated by a distinctive sulfur scaffold,namely nitrogen doped gra phitic ladder-structured carbon nanotubes(NGLCNTs)loaded with appropriate amount of metallic cobalt nanoparticles.Benefiting from both the unique graphitic ladder-structure and metallic cobalt nano particles in the nitrogen doped carbon nanotubes,the NGLCNTs host not only promotes ion transfer and electron transmission during the redox reactions from higher-order polysulfides to Li_(2)S_(2)/Li_(2)S,but also effciently restricts the outward diffusion and dissolution of polysulfides as well as benefits the nucleation and growth of Li_(2)S.As a result,the NGLCNTs/S cathode has successfully overcome the crucial issues,and it exhibits greatly enhanced electrochemical performances with excellent rate capabilities of up to 8C and long term cycling life of over 500 cycles.
基金supported by the NSFC(21373279,21501067,21601002 and 91422302)the Zhejiang Provincial Natural Science Foundation of China(Grant LQ15B010002)+1 种基金the Program for Science and Technology of Jiaxing(2015AY11011)the Start-up Grant from Jiaxing University(no.70514017).
文摘Few spin-crossover materials with a 1D ladder-type structure have been reported.Previously,[Fe(Mebpt){Au(CN)_(2)}]·H_(2)O(MebptH=3-(5-methyl-2-pyridyl)-5-(2-pyridyl)-1,2,4-triazole)was made and shown to display gradual spin-crossover behaviour.In the current work,a new 1D iron(Ⅱ)ladder-type compound,[Fe(bpt){Au(CN)_(2)}](bptH=3-(2-pyridyl)-5-(2-pyridyl)-1,2,4-triazole),was produced and showed enhanced spin-crossover behavior.It showed an abrupt spin transition above room temperature with a 3 K hysteresis(T_(1/2)↓=335 K and T_(1/2)↑=338 K).The origin of its enhanced spin-crossover could be ascribed to a greater influence of supramolecular interactions over the electronic substituent effect.
