LIRR＇s Priject of ＂Research on Spalling Mechanism Due to Rapid Heating-up of Dense Refractory Castables＂ declared by Wang Zhanmin,vice-president of LIRR,will gain the fund support from National Natural Science Foun...LIRR＇s Priject of ＂Research on Spalling Mechanism Due to Rapid Heating-up of Dense Refractory Castables＂ declared by Wang Zhanmin,vice-president of LIRR,will gain the fund support from National Natural Science Foundation of China in 2011.展开更多
In this work,we revisited the single-step synthesis of CdE(E=S,Se,and Te)quantum dots(QDs).Powdered CdO and elemental chalcogen were directly used for heating-up synthesis.Firstly,the in situ dissolution of the solid ...In this work,we revisited the single-step synthesis of CdE(E=S,Se,and Te)quantum dots(QDs).Powdered CdO and elemental chalcogen were directly used for heating-up synthesis.Firstly,the in situ dissolution of the solid precursors and related QD formation channels were preliminarily investigated.In general,QDs were generated from homogeneous reactions between dissolved cadmium and chalcogen precursors in bulk solution.We found that,during single-step synthesis,both the dissolution of CdO and selenium proceeded faster than their ex situ dissolution respectively.To explain this result,we proposed the existence of extra surface reaction channels for QD formation.That is,QDs could also be generated via on-surface reactions between the solid precursors and the dissolved counter precursors(as“ligands”).The happening of these extra surface reactions would increase the overall dissolution rate of CdO and selenium.Further,the circulation of oleic acid which is peculiar to such single-step synthesis should also partly account for the accelerated dissolution of CdO.Finally,by comparing with two-step synthesis using pre-dissolved CdO,we presented that such single-step synthesis was reliable in making uniform CdE QDs with good reproducibility.Our work reaffirmed the great potential of this single-step strategy in cost-effective synthesis of monodisperse QDs.Moreover,the ligand-promoted surface reaction channels would be applicable in solution-phase synthesis of metal chalcogenide nanocrystals from solid precursors.展开更多
Nickel nanoparticles were synthesized through the thermal decomposition of nickel（II） acetylacetonate in con- junction with the two methods of hot-injection and heating-up at elevated temperatures in alkylamine. Usi...Nickel nanoparticles were synthesized through the thermal decomposition of nickel（II） acetylacetonate in con- junction with the two methods of hot-injection and heating-up at elevated temperatures in alkylamine. Using several mole ratios of the oleic acid, different morphologies were obtained. The synthesized particles were characterized via XRD, SEM, TEM, SAED and EDAX. Mean particle size was revealed to range from 25 to 45 nm. Presence of crystallized particles in HCP with little FCC phases was also confirmed with XRD patterns. Magnetic hysteresis loops measured by the VSM showed that the magnetic properties of Ni nanoparticles （i.e., coercivity, saturation magnetization and relative permeability） were much enhanced in comparison with the bulk.展开更多
文摘LIRR＇s Priject of ＂Research on Spalling Mechanism Due to Rapid Heating-up of Dense Refractory Castables＂ declared by Wang Zhanmin,vice-president of LIRR,will gain the fund support from National Natural Science Foundation of China in 2011.
基金by the opening project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(Nos.sklpme2019-4-38 and sklpme2019-4-36)L.X.is grateful to the National Natural Science Foundation of China(NSFC,No.22005205).
文摘In this work,we revisited the single-step synthesis of CdE(E=S,Se,and Te)quantum dots(QDs).Powdered CdO and elemental chalcogen were directly used for heating-up synthesis.Firstly,the in situ dissolution of the solid precursors and related QD formation channels were preliminarily investigated.In general,QDs were generated from homogeneous reactions between dissolved cadmium and chalcogen precursors in bulk solution.We found that,during single-step synthesis,both the dissolution of CdO and selenium proceeded faster than their ex situ dissolution respectively.To explain this result,we proposed the existence of extra surface reaction channels for QD formation.That is,QDs could also be generated via on-surface reactions between the solid precursors and the dissolved counter precursors(as“ligands”).The happening of these extra surface reactions would increase the overall dissolution rate of CdO and selenium.Further,the circulation of oleic acid which is peculiar to such single-step synthesis should also partly account for the accelerated dissolution of CdO.Finally,by comparing with two-step synthesis using pre-dissolved CdO,we presented that such single-step synthesis was reliable in making uniform CdE QDs with good reproducibility.Our work reaffirmed the great potential of this single-step strategy in cost-effective synthesis of monodisperse QDs.Moreover,the ligand-promoted surface reaction channels would be applicable in solution-phase synthesis of metal chalcogenide nanocrystals from solid precursors.
文摘Nickel nanoparticles were synthesized through the thermal decomposition of nickel（II） acetylacetonate in con- junction with the two methods of hot-injection and heating-up at elevated temperatures in alkylamine. Using several mole ratios of the oleic acid, different morphologies were obtained. The synthesized particles were characterized via XRD, SEM, TEM, SAED and EDAX. Mean particle size was revealed to range from 25 to 45 nm. Presence of crystallized particles in HCP with little FCC phases was also confirmed with XRD patterns. Magnetic hysteresis loops measured by the VSM showed that the magnetic properties of Ni nanoparticles （i.e., coercivity, saturation magnetization and relative permeability） were much enhanced in comparison with the bulk.
