The present work aims to enhance the ballistic resistance of AA7005 alloy by incorporating the TiB2 and B4C ceramic reinforcement particles. Surface composites with different weight fractions of TiB2 and B4C particles...The present work aims to enhance the ballistic resistance of AA7005 alloy by incorporating the TiB2 and B4C ceramic reinforcement particles. Surface composites with different weight fractions of TiB2 and B4C particles were processed by friction stir processing. Micro-hardness and depth of penetration tests were carried out to evaluate the ballistic properties of the surface composites. The surface hardness of the composite was found to be nearly 70 HV higher than base alloy. The depth of penetration of the steel projectile was 20e26mm in the composites as compared to 37mm in the base alloy. Ballistic mass efficiency factor of the surface composite was found to be 1.6 times higher than base alloy. This is mainly attributed to the dispersion strengthening from the reinforcement particles.展开更多
Emerging as an outperformed class of metal-organic frameworks(MOFs),square-octahedron(soc)topology MOFs(soc-MOFs)feature superior properties of high porosity,large gas storage capacity,and excellent thermal/chemical s...Emerging as an outperformed class of metal-organic frameworks(MOFs),square-octahedron(soc)topology MOFs(soc-MOFs)feature superior properties of high porosity,large gas storage capacity,and excellent thermal/chemical stability.We report here an iron based soc-MOF,denoted as Fe-pbpta(H4pbpta=4,4',4'',4'''-(1,4-phenylenbis(pyridine-4,2-6-triyl))-tetrabenzoic acid)possessing a very high Brunauer,Emmett and Teller(BET)surface area of 4,937 m2/g and a large pore volume of 2.15 cm3/g.The MOF demonstrates by far the highest gravimetric uptake of 369 cm3(STP)/g under the DOE operational storage conditions(35 bar and 298 K)and a high volumetric deliverable capacity of 192 cc/cc at 298 K and 65 bar.Furthermore,Fe-pbpta exhibits high thermal and aqueous stability making it a promising candidate for on-board methane storage.展开更多
Metal-organic frameworks(MOFs)have garnered multidisciplinary attention due to their structural tailorability,controlled pore size,and physicochemical functions,and their inherent properties can be exploited by applyi...Metal-organic frameworks(MOFs)have garnered multidisciplinary attention due to their structural tailorability,controlled pore size,and physicochemical functions,and their inherent properties can be exploited by applying them as precursors and/or templates for fabricating derived hollow porous nanomaterials.The fascinating,functional properties and applications of MOFderived hollow porous materials primarily lie in their chemical composition,hollow character,and unique porous structure.Herein,a comprehensive overview of the synthetic strategies and emerging applications of hollow porous materials derived from MOF-based templates and/or precursors is given.Based on the role of MOFs in the preparation of hollow porous materials,the synthetic strategies are described in detail,including(1)MOFs as removable templates,(2)MOF nanocrystals as both self-sacrificing templates and precursors,(3)MOF@secondary-component core-shell composites as precursors,and(4)hollow MOF nanocrystals and their composites as precursors.Subsequently,the applications of these hollow porous materials for chemical catalysis,electrocatalysis,energy storage and conversion,and environmental management are presented.Finally,a perspective on the research challenges and future opportunities and prospects for MOF-derived hollow materials is provided.展开更多
基金supported by Defence Institute of Advanced Technology(DIAT),Pune(DIAT-In house Project)
文摘The present work aims to enhance the ballistic resistance of AA7005 alloy by incorporating the TiB2 and B4C ceramic reinforcement particles. Surface composites with different weight fractions of TiB2 and B4C particles were processed by friction stir processing. Micro-hardness and depth of penetration tests were carried out to evaluate the ballistic properties of the surface composites. The surface hardness of the composite was found to be nearly 70 HV higher than base alloy. The depth of penetration of the steel projectile was 20e26mm in the composites as compared to 37mm in the base alloy. Ballistic mass efficiency factor of the surface composite was found to be 1.6 times higher than base alloy. This is mainly attributed to the dispersion strengthening from the reinforcement particles.
基金the U.S.Department of Energy's Office of Energy Efficiency and Renewable Energy under the Hydrogen and Fuel Cell Technologies and Vehicle Technologies Offices under Award Number DE-EE0008812.S.K.acknowledges the financial support from the University Grants Commission(UGC),New Delhi,India(No.F 5-80/2014(IC)).ChemMatCARS Sector 15 is principally supported by the Divisions of Chemistry(CHE)and Materials Research(DMR),National Science Foundation,under Grant Number NSF/CHE-1346572.Use of the Advanced Photon Source,an Office of Science User Facility operated for the U.S.Department of Energy(DOE)Office of Science by Argonne National Laboratory,was supported by the U.S.DOE under Contract No.DE-AC02-06CH11357.G.V.would further like to acknowledge Jason Exley(Sales Engineer,Micromeritics USA)for help and support provided with the measurements and the HKUST reference data.
文摘Emerging as an outperformed class of metal-organic frameworks(MOFs),square-octahedron(soc)topology MOFs(soc-MOFs)feature superior properties of high porosity,large gas storage capacity,and excellent thermal/chemical stability.We report here an iron based soc-MOF,denoted as Fe-pbpta(H4pbpta=4,4',4'',4'''-(1,4-phenylenbis(pyridine-4,2-6-triyl))-tetrabenzoic acid)possessing a very high Brunauer,Emmett and Teller(BET)surface area of 4,937 m2/g and a large pore volume of 2.15 cm3/g.The MOF demonstrates by far the highest gravimetric uptake of 369 cm3(STP)/g under the DOE operational storage conditions(35 bar and 298 K)and a high volumetric deliverable capacity of 192 cc/cc at 298 K and 65 bar.Furthermore,Fe-pbpta exhibits high thermal and aqueous stability making it a promising candidate for on-board methane storage.
基金Financial support from the National Key Research and Development Program of China(2018YFC1900105)NSFC(22006036+1 种基金U2167218)Beijing Outstanding Young Scientist Program is greatly appreciated。
文摘Metal-organic frameworks(MOFs)have garnered multidisciplinary attention due to their structural tailorability,controlled pore size,and physicochemical functions,and their inherent properties can be exploited by applying them as precursors and/or templates for fabricating derived hollow porous nanomaterials.The fascinating,functional properties and applications of MOFderived hollow porous materials primarily lie in their chemical composition,hollow character,and unique porous structure.Herein,a comprehensive overview of the synthetic strategies and emerging applications of hollow porous materials derived from MOF-based templates and/or precursors is given.Based on the role of MOFs in the preparation of hollow porous materials,the synthetic strategies are described in detail,including(1)MOFs as removable templates,(2)MOF nanocrystals as both self-sacrificing templates and precursors,(3)MOF@secondary-component core-shell composites as precursors,and(4)hollow MOF nanocrystals and their composites as precursors.Subsequently,the applications of these hollow porous materials for chemical catalysis,electrocatalysis,energy storage and conversion,and environmental management are presented.Finally,a perspective on the research challenges and future opportunities and prospects for MOF-derived hollow materials is provided.
