为了探究表面活性剂对BiFeO_3单晶纳米线形貌及性能的影响,采用沉淀法制备前驱体,并辅以表面活性剂采用水热法制备BiFeO_3纳米线,利用X线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和UV3600分光光度计对不同量和种类的表...为了探究表面活性剂对BiFeO_3单晶纳米线形貌及性能的影响,采用沉淀法制备前驱体,并辅以表面活性剂采用水热法制备BiFeO_3纳米线,利用X线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和UV3600分光光度计对不同量和种类的表面活性剂以及不同水热反应时间下所得BiFeO_3纳米线的微观形貌、结构和性能进行测试分析.实验结果表明:适当的表面活性剂浓度以及恰当的水热温度和时间有利于BiFeO_3纳米线的形成,140℃的水热温度、48 h的反应时间以及0.0605g的十六烷基三甲基溴化铵(C_(16)H_(33)(CH_3)_3NBr,CTAB)反应所得BiFeO_3纳米线的表面形貌最好;TEM和选区域电子衍射(SAED)结果表明制备所得样品为单晶,且具有高度结晶性,XRD结果表明所得BiFeO_3纳米线为纯相;所得BiFeO_3纳米线在可见光范围均有较好的吸收,且带隙为1.8 e V.此外,通过对比实验数据可知BiFeO_3纳米线的形成机制与晶体成核和晶体生长间的竞争作用以及晶体选择性吸附生长有关.展开更多
Multiferroic material as a photovoltaic material has gained considerable attention in recent years.Nanoparticles（NPs）La_（0.1）Bi_（0.9-x）Sr_xFeO_y（LBSF,x = 0,0.2,0.4） with dopant Sr^（2＋）ions were synthesized ...Multiferroic material as a photovoltaic material has gained considerable attention in recent years.Nanoparticles（NPs）La_（0.1）Bi_（0.9-x）Sr_xFeO_y（LBSF,x = 0,0.2,0.4） with dopant Sr^（2＋）ions were synthesized by the sol–gel method.A systematic change in the crystal structure from rhombohedral to tetragonal upon increasing Sr doping was observed.There is an obvious change in the particle size from 180 nm to 50 nm with increasing Sr substitution into LBFO.It was found that Sr doping effectively narrows the band gap from～2.08 e V to～1.94 e V,while it leads to an apparent enhancement in the electrical conductivity of LBSF NPs,making a transition from insulator to semiconductor.This suggests an effective way to modulate the conductivity of BiFeO_（3-）based multiferroic materials with pure phase by co-doping with La and Sr at the A sites of BiFeO_3.展开更多
The heavy fragments in heavy-ion collisions are finally formed after the hot prefragments undergo sequential decay, of whom the temperature should be much lower than that of prefragments. Using the double ratio （DR）...The heavy fragments in heavy-ion collisions are finally formed after the hot prefragments undergo sequential decay, of whom the temperature should be much lower than that of prefragments. Using the double ratio （DR） method, the isotopic thermometer （Tiso ） for heavy fragment is constructed using the yield of heavy isotopes. Tiso of heavy fragment is obtained by analyzing the measured data in the 1A GeV 124＇136Xe and 140A MeV 48Ca/64Ni reactions. Result shows that Tiso varies from 0.5 MeV to 10 MeV. But most Tiso is around 1 4- 0.5 MeV, which is much lower than temperature of light particles. Result also indicates that the difference between Tiso of heavy fragments in different reactions is very small, and ~o is independent on the size of the reaction system, the incident energy and the neutron-richness of the projectile.展开更多
文摘为了探究表面活性剂对BiFeO_3单晶纳米线形貌及性能的影响,采用沉淀法制备前驱体,并辅以表面活性剂采用水热法制备BiFeO_3纳米线,利用X线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和UV3600分光光度计对不同量和种类的表面活性剂以及不同水热反应时间下所得BiFeO_3纳米线的微观形貌、结构和性能进行测试分析.实验结果表明:适当的表面活性剂浓度以及恰当的水热温度和时间有利于BiFeO_3纳米线的形成,140℃的水热温度、48 h的反应时间以及0.0605g的十六烷基三甲基溴化铵(C_(16)H_(33)(CH_3)_3NBr,CTAB)反应所得BiFeO_3纳米线的表面形貌最好;TEM和选区域电子衍射(SAED)结果表明制备所得样品为单晶,且具有高度结晶性,XRD结果表明所得BiFeO_3纳米线为纯相;所得BiFeO_3纳米线在可见光范围均有较好的吸收,且带隙为1.8 e V.此外,通过对比实验数据可知BiFeO_3纳米线的形成机制与晶体成核和晶体生长间的竞争作用以及晶体选择性吸附生长有关.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11104202 and 51572193)
文摘Multiferroic material as a photovoltaic material has gained considerable attention in recent years.Nanoparticles（NPs）La_（0.1）Bi_（0.9-x）Sr_xFeO_y（LBSF,x = 0,0.2,0.4） with dopant Sr^（2＋）ions were synthesized by the sol–gel method.A systematic change in the crystal structure from rhombohedral to tetragonal upon increasing Sr doping was observed.There is an obvious change in the particle size from 180 nm to 50 nm with increasing Sr substitution into LBFO.It was found that Sr doping effectively narrows the band gap from～2.08 e V to～1.94 e V,while it leads to an apparent enhancement in the electrical conductivity of LBSF NPs,making a transition from insulator to semiconductor.This suggests an effective way to modulate the conductivity of BiFeO_（3-）based multiferroic materials with pure phase by co-doping with La and Sr at the A sites of BiFeO_3.
基金Supported by National Natural Science Foundation of China under Grant No. 10905017Program for Innovative Research Team(in Science and Technology) under Grant No. 2010IRTSTHN002 in Universities of Henan Province+1 种基金Program for Science & TechnologyInnovation Talents in Universities of Henan Province (HASTIT)the Young Teacher Project in Henan Normal University,China
文摘The heavy fragments in heavy-ion collisions are finally formed after the hot prefragments undergo sequential decay, of whom the temperature should be much lower than that of prefragments. Using the double ratio （DR） method, the isotopic thermometer （Tiso ） for heavy fragment is constructed using the yield of heavy isotopes. Tiso of heavy fragment is obtained by analyzing the measured data in the 1A GeV 124＇136Xe and 140A MeV 48Ca/64Ni reactions. Result shows that Tiso varies from 0.5 MeV to 10 MeV. But most Tiso is around 1 4- 0.5 MeV, which is much lower than temperature of light particles. Result also indicates that the difference between Tiso of heavy fragments in different reactions is very small, and ~o is independent on the size of the reaction system, the incident energy and the neutron-richness of the projectile.
