The soft magnetic materials have potential applications in the field of bioengineering as carriers for targeted drug delivery. The magnetic properties, particle size after coating, Curie temperature and its biocompati...The soft magnetic materials have potential applications in the field of bioengineering as carriers for targeted drug delivery. The magnetic properties, particle size after coating, Curie temperature and its biocompatibility are important parameters for the synthesis of materials. In the present communication cobalt ferrite nanoparticles have been synthesized using co-precipitation method and coated with sodium alginate. The X-ray diffraction and infrared spectroscopic measurements have been used to confirm the ferrite structure formation and coating of the samples with alginate. The SEM micrographs have been used to confirm the particle size which is found to be 45 nm before coating and 78 nm after coating. The saturation magnetization obtained using the hysteresis data for the uncoated cobalt ferrite sample is 19.8 emu/gm while for the coated sample it reduces to 10.2 emu/gm. The AC susceptibility measurements indicate SP structure for the uncoated samples with Curie temperature less than 100℃. The thermo gravimetric measurements have been used to estimate the amount of alginate coating on the sample and it has been correlated with retention of magnetic properties after coating. The value of saturation magnetization reduces after coating due to mass reduction of magnetic material in the sample in accordance with the TGA measurements.展开更多
The carbon-coated ZnO nanospheres materials have been synthesized via a simple hydrothermal method.The effect of carbon content on the microstructure,morphology and electrochemical performance of the materials was inv...The carbon-coated ZnO nanospheres materials have been synthesized via a simple hydrothermal method.The effect of carbon content on the microstructure,morphology and electrochemical performance of the materials was investigated by XRD,Raman spectroscopy,transmission electron microscopy,scanning electron microscopy and electrochemical techniques.Research results show that the spherical ZnO/C material with a carbon cladding content of 10%is very homogeneous and approximately 200 nm in size.The electrochemical performances of the ZnO/C nanospheres as an anode materials are examines.The ZnO/C exhibits better stability than pure ZnO,excellent lithium storage properties as well as improved circulation performance.The Coulomb efficiency of the ZnO/C with 10%carbon coated content reaches 98%.The improvement of electrochemical performance can be attributed to the carbon layer on the ZnO surface.The large volume change of ZnO during the charge-discharge process can be effectively relieved.展开更多
Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple synthesis.Cycling performance is an important criterion for evaluating the applicat...Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple synthesis.Cycling performance is an important criterion for evaluating the application prospects of batteries.However,facing challenges,including phase transitions,ambient stability,side reactions,and irreversible anionic oxygen activity,the cycling performance of layered oxide cathode materials still cannot meet the application requirements.Therefore,this review proposes several strategies to address these challenges.First,bulk doping is introduced from three aspects:cationic single doping,anionic single doping,and multi-ion doping.Second,homogeneous surface coating and concentration gradient modification are reviewed.In addition,methods such as mixed structure design,particle engineering,high-entropy material construction,and integrated modification are proposed.Finally,a summary and outlook provide a new horizon for developing and modifying layered oxide cathode materials.展开更多
Dental restorative materials with high mechanical properties and biocompatible performances are promising.In this work,polymer-infiltrated-ceramic-network materials(PICNs)were fabricated via infiltrating polymerizable...Dental restorative materials with high mechanical properties and biocompatible performances are promising.In this work,polymer-infiltrated-ceramic-network materials(PICNs)were fabricated via infiltrating polymerizable monomers into porous ceramic networks and incorporated with hydroxyapatite nano-powders.Our results revealed that the flexural strength can be enhanced up to 157.32 MPa,and elastic modulus and Vickers hardness can be achieved up to 19.4 and 1.31 GPa,respectively,which are comparable with the commercial computer-aided design and computer-aided manufacturing(CAD/CAM)blocks.Additionally,the adhesion and spreading of rat bone marrow mesenchymal stem cells(r BMSCs)on the surface of such materials can be improved by adding hydroxyapatite,which results in good biocompatibility.Such PICNs are potential applicants for their application in the dental restoration.展开更多
Nickel-rich cathode materials are increasingly being applied in commercial lithium-ion batteries to realize higher specific capacity as well as improved energy density.However,low structural stability and rapid capaci...Nickel-rich cathode materials are increasingly being applied in commercial lithium-ion batteries to realize higher specific capacity as well as improved energy density.However,low structural stability and rapid capacity decay at high voltage and temperature hinder their rapid large-scale application.Herein,a wet chemical method followed by a post-annealing process is utilized to realize the surface coating of tantalum oxide on LiNi_(0.88)Mn_(0.03)Co_(0.09)O_(2),and the electrochemical performance is improved.The modified Li Ni_(0.88)Mn_(0.03)Co_(0.09)O_(2)displays an initial discharge capacity of~233 m Ah/g at0.1 C and 174 m Ah/g at 1 C after 150 cycles in the voltage range of 3.0 V–4.4 V at 45℃,and it also exhibits an enhanced rate capability with 118 m Ah/g at 5 C.The excellent performance is due to the introduction of tantalum oxide as a stable and functional layer to protect the surface of LiNi_(0.88)Mn_(0.03)Co_(0.09)O_(2),and the surface side reactions and cation mixing are suppressed at the same time without hampering the charge transfer kinetics.展开更多
A triethylenetetramine epoxy mixture was synthesized through the reaction of a low-molecular-weight liquid epoxy resin with triethylenetetramine(TETA).Then triethyltetramine(TETA)was injected dropwise into a pro-pylen...A triethylenetetramine epoxy mixture was synthesized through the reaction of a low-molecular-weight liquid epoxy resin with triethylenetetramine(TETA).Then triethyltetramine(TETA)was injected dropwise into a pro-pylene glycol methyl ether(PM)solution for chain extension reaction.A hydrophilic andflexible polyether seg-ment was introduced into the hardener molecule.The effects of TETA/DGEPG,reaction temperature and reaction time on the epoxy conversion of polyethylene glycol diglycidyl ether(DGEPG)were studied.In addition,several alternate strategies to add epoxy resin to the high-speed dispersion machine and synthesize MEA DGEBA adduct(without catalyst and with bisphenol A diglycidyl ether epoxy resin)were compared.It was found that the higher the molecular weight of triethylenetetramine,the longer the chain segment of the surface active molecule.When the equivalence ratio of amine hydrogen and epoxy group is low,the stability of lotion is good.When the ratio of amine hydrogen to epoxy group is large,the content of triethylenetetramine is small.The main objective of this study is the provision of new data and knowledge for the development of new materials in the coating and electronic industry.展开更多
文摘The soft magnetic materials have potential applications in the field of bioengineering as carriers for targeted drug delivery. The magnetic properties, particle size after coating, Curie temperature and its biocompatibility are important parameters for the synthesis of materials. In the present communication cobalt ferrite nanoparticles have been synthesized using co-precipitation method and coated with sodium alginate. The X-ray diffraction and infrared spectroscopic measurements have been used to confirm the ferrite structure formation and coating of the samples with alginate. The SEM micrographs have been used to confirm the particle size which is found to be 45 nm before coating and 78 nm after coating. The saturation magnetization obtained using the hysteresis data for the uncoated cobalt ferrite sample is 19.8 emu/gm while for the coated sample it reduces to 10.2 emu/gm. The AC susceptibility measurements indicate SP structure for the uncoated samples with Curie temperature less than 100℃. The thermo gravimetric measurements have been used to estimate the amount of alginate coating on the sample and it has been correlated with retention of magnetic properties after coating. The value of saturation magnetization reduces after coating due to mass reduction of magnetic material in the sample in accordance with the TGA measurements.
基金Funded by the Key Research Projects in Gansu Province(No.17YF1GA020)。
文摘The carbon-coated ZnO nanospheres materials have been synthesized via a simple hydrothermal method.The effect of carbon content on the microstructure,morphology and electrochemical performance of the materials was investigated by XRD,Raman spectroscopy,transmission electron microscopy,scanning electron microscopy and electrochemical techniques.Research results show that the spherical ZnO/C material with a carbon cladding content of 10%is very homogeneous and approximately 200 nm in size.The electrochemical performances of the ZnO/C nanospheres as an anode materials are examines.The ZnO/C exhibits better stability than pure ZnO,excellent lithium storage properties as well as improved circulation performance.The Coulomb efficiency of the ZnO/C with 10%carbon coated content reaches 98%.The improvement of electrochemical performance can be attributed to the carbon layer on the ZnO surface.The large volume change of ZnO during the charge-discharge process can be effectively relieved.
基金the Fundamental Research Funds for the Central Universities,China(No.06500177)the National Natural Science Foundation of China Joint Fund Project(No.U1764255)。
文摘Layered oxide is a promising cathode material for sodium-ion batteries because of its high-capacity,high operating voltage,and simple synthesis.Cycling performance is an important criterion for evaluating the application prospects of batteries.However,facing challenges,including phase transitions,ambient stability,side reactions,and irreversible anionic oxygen activity,the cycling performance of layered oxide cathode materials still cannot meet the application requirements.Therefore,this review proposes several strategies to address these challenges.First,bulk doping is introduced from three aspects:cationic single doping,anionic single doping,and multi-ion doping.Second,homogeneous surface coating and concentration gradient modification are reviewed.In addition,methods such as mixed structure design,particle engineering,high-entropy material construction,and integrated modification are proposed.Finally,a summary and outlook provide a new horizon for developing and modifying layered oxide cathode materials.
基金Beijing Municipal Science&Technology Commission(No of China.Z171100002017009)National Natural Science Foundation of China(Grant No.81671026)。
文摘Dental restorative materials with high mechanical properties and biocompatible performances are promising.In this work,polymer-infiltrated-ceramic-network materials(PICNs)were fabricated via infiltrating polymerizable monomers into porous ceramic networks and incorporated with hydroxyapatite nano-powders.Our results revealed that the flexural strength can be enhanced up to 157.32 MPa,and elastic modulus and Vickers hardness can be achieved up to 19.4 and 1.31 GPa,respectively,which are comparable with the commercial computer-aided design and computer-aided manufacturing(CAD/CAM)blocks.Additionally,the adhesion and spreading of rat bone marrow mesenchymal stem cells(r BMSCs)on the surface of such materials can be improved by adding hydroxyapatite,which results in good biocompatibility.Such PICNs are potential applicants for their application in the dental restoration.
基金Project supported by the Key Laboratory Fund(Grant No.6142804200303)from Science and Technology on Microsystem Laboratorythe Key Research Program of Frontier Sciences of the Chinese Academy of Sciences:Original Innovation Projects from 0 to 1(Grant No.ZDBS-LY-JSC010)+2 种基金the Key Research and Development Project of the Department of Science and Technology of Jiangsu Province,China(Grant No.BE2020003)the Beijing Municipal Science and Technology Commission(Grant No.Z191100004719001)the National Key Research and Development Program of China(Grant No.2017YFB0405400)。
文摘Nickel-rich cathode materials are increasingly being applied in commercial lithium-ion batteries to realize higher specific capacity as well as improved energy density.However,low structural stability and rapid capacity decay at high voltage and temperature hinder their rapid large-scale application.Herein,a wet chemical method followed by a post-annealing process is utilized to realize the surface coating of tantalum oxide on LiNi_(0.88)Mn_(0.03)Co_(0.09)O_(2),and the electrochemical performance is improved.The modified Li Ni_(0.88)Mn_(0.03)Co_(0.09)O_(2)displays an initial discharge capacity of~233 m Ah/g at0.1 C and 174 m Ah/g at 1 C after 150 cycles in the voltage range of 3.0 V–4.4 V at 45℃,and it also exhibits an enhanced rate capability with 118 m Ah/g at 5 C.The excellent performance is due to the introduction of tantalum oxide as a stable and functional layer to protect the surface of LiNi_(0.88)Mn_(0.03)Co_(0.09)O_(2),and the surface side reactions and cation mixing are suppressed at the same time without hampering the charge transfer kinetics.
基金This work is financially supported by a University-Level Doctoral Research Start-Up Fund in 2019.
文摘A triethylenetetramine epoxy mixture was synthesized through the reaction of a low-molecular-weight liquid epoxy resin with triethylenetetramine(TETA).Then triethyltetramine(TETA)was injected dropwise into a pro-pylene glycol methyl ether(PM)solution for chain extension reaction.A hydrophilic andflexible polyether seg-ment was introduced into the hardener molecule.The effects of TETA/DGEPG,reaction temperature and reaction time on the epoxy conversion of polyethylene glycol diglycidyl ether(DGEPG)were studied.In addition,several alternate strategies to add epoxy resin to the high-speed dispersion machine and synthesize MEA DGEBA adduct(without catalyst and with bisphenol A diglycidyl ether epoxy resin)were compared.It was found that the higher the molecular weight of triethylenetetramine,the longer the chain segment of the surface active molecule.When the equivalence ratio of amine hydrogen and epoxy group is low,the stability of lotion is good.When the ratio of amine hydrogen to epoxy group is large,the content of triethylenetetramine is small.The main objective of this study is the provision of new data and knowledge for the development of new materials in the coating and electronic industry.
