In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca3Mn2O7 under pressures up to 35 GPa have been Performed by using diamond anvil cell with synchrotron radiat...In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca3Mn2O7 under pressures up to 35 GPa have been Performed by using diamond anvil cell with synchrotron radiation.The results show that the structure of layered perovskite-like manganate Ca3Mn2O7 is unstable under pressure due to the easy compression of NaCl-type blocks.The structure of Ca3Mn2O7 underwent two phase transitions under pressures in the range of 0-35GPa.One was at about 1.3GPa with the crystal structure changing from tetragonalt go orthorhombic.The other was at about 9.5GPa with the crystal structure changing form orthorhombic back to another tetragonal.展开更多
Elastic properties are important in fundamental understanding of multiferroic materials. However, up to now, there is no work about anisotropy of elastic properties in orthorhombic Ca_3Mn_2O_7. In this study, using co...Elastic properties are important in fundamental understanding of multiferroic materials. However, up to now, there is no work about anisotropy of elastic properties in orthorhombic Ca_3Mn_2O_7. In this study, using coordinate transformation method, we investigated basic elastic parameters(elastic constants c'_(ij)) and engineering elastic parameters(Young's modulus E, Poisson's ratio v, and the rigidity modulus G') of orthorhombic Ca_3Mn_2O_7 along arbitrary orientations. The detailed anisotropic characteristics of these parameters were presented. The results reveal the orientation related elastic properties in mm2 point group orthorhombic Ca_3Mn_2O_7.展开更多
New phosphors Sr2ZnSi2O7： M （M=Mn2＋, Tb3＋） were synthesized through solid-state reaction, and their photoluminescent properties under UV and VUV region were investigated. The results showed that Sr2ZnSi2O7：Mn2＋...New phosphors Sr2ZnSi2O7： M （M=Mn2＋, Tb3＋） were synthesized through solid-state reaction, and their photoluminescent properties under UV and VUV region were investigated. The results showed that Sr2ZnSi2O7：Mn2＋ emitted green light with the strongest emission peak centered at 525 nm, and its quenching concentration under 254 and 147 nm excitation occurred at x = 0.08 and 0.06, respectively. Sr2ZnSi2O7： Th3＋ emitted green light with the strongest emission peak centered at 541 nm, and its quenching concentration under 254 and 147 nm excitation also appeared at y = 0.25. At 147 nm excitation, the emission intensities of Sr2Zn0.54Si2O7： 0.06Mn2＋ and Sr1.75ZnSi2O7： 0.25Tb3＋ phosphors were 54% and 36% of that of Zn1.96SiO4：0.04Mn2＋, respectively. And their decay times （τ1/e） were about 3.18 ms and 3.9 ms, respectively.展开更多
ZHOU Bai-Bin *,1,2 WEI Yong-De 1 LI Zhong-Hua 1 ( 1 Department of Applied Chemistry,Ha rbin Institute of Technology ￡?Harbin￡±￡ì￡°￡°￡°￡±￡(c)( 2 Department of Chemistry,Harbin Norm...ZHOU Bai-Bin *,1,2 WEI Yong-De 1 LI Zhong-Hua 1 ( 1 Department of Applied Chemistry,Ha rbin Institute of Technology ￡?Harbin￡±￡ì￡°￡°￡°￡±￡(c)( 2 Department of Chemistry,Harbin Normal University￡?Harbin￡±￡ì￡°￡°￡?￡°￡(c) The air-solid interface reaction of Ce,Lu with K10 H 3[Gd (SiMo 4 W￡*O￡3￡1￡(c) 2]through chemistry-heated permeation is reported for the fi rst time￡(r)The permeated complex is characterized by ICP and the result shows tha t the mini mum Ce,Lu can permeate into the inner sph ere of K 10 H ￡3 ￡?Gd ￡¨SiMo ￡′ W ￡* O ￡3￡1 ￡(c) 2]The IR ,XRD patterns give the eviden ce that after permeation the comple x still keeps the Keggin structure,howe ver,its crystal structure is different from the complex before permeation￡(r)The cond uctivity of the permeated complex has been measured with the four-electr ode method and the data show that the co nductivity of the complex after permeation is 10 6 times higher than that of the sample before permeation and reaches ￡′￡(r)84 6×10 -1 S·cm -1 ￡(r)These indicate that the permeated c omplex is a good solid electrolyte and further appli cations are also expected￡(r)展开更多
A single-phased silicate compound （Ba1-xCex）9（Sc1-yMny）2Si6O24 was prepared by solid-state reaction at high temperature. From powder X-ray diffraction （XRD） analysis, the formation of Ba9Sc2Si6O24 with an R3 spa...A single-phased silicate compound （Ba1-xCex）9（Sc1-yMny）2Si6O24 was prepared by solid-state reaction at high temperature. From powder X-ray diffraction （XRD） analysis, the formation of Ba9Sc2Si6O24 with an R3 space group was confirmed. In the photoluminescence spectra under ultraviolet （UV） ray excitation, the Ba9Sc2Si6O24：Ce3＋,Mn2＋ phosphor emits two distinctive color light bands： a blue one originating from Ce3＋and a red one caused by Mn2＋. The energy transfer process from Ce3＋ to Mn2＋ was confirmed, the critical radius as well as the transfer efficiency was calculated, and the energy transfer mechanism was discussed. In addition, the decay-time testing indicates that the energy transfer efficiencies from Ce（1） to Mn2＋ and Ce（2） to Mn2＋ are different. The emission chromaticity of Ba9Sc2Si6O24：Ce3＋,Mn2＋ phosphor could be tuned from blue to red by altering the Ce3＋/Mn2＋ concentration ratio.展开更多
文摘In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca3Mn2O7 under pressures up to 35 GPa have been Performed by using diamond anvil cell with synchrotron radiation.The results show that the structure of layered perovskite-like manganate Ca3Mn2O7 is unstable under pressure due to the easy compression of NaCl-type blocks.The structure of Ca3Mn2O7 underwent two phase transitions under pressures in the range of 0-35GPa.One was at about 1.3GPa with the crystal structure changing from tetragonalt go orthorhombic.The other was at about 9.5GPa with the crystal structure changing form orthorhombic back to another tetragonal.
文摘Elastic properties are important in fundamental understanding of multiferroic materials. However, up to now, there is no work about anisotropy of elastic properties in orthorhombic Ca_3Mn_2O_7. In this study, using coordinate transformation method, we investigated basic elastic parameters(elastic constants c'_(ij)) and engineering elastic parameters(Young's modulus E, Poisson's ratio v, and the rigidity modulus G') of orthorhombic Ca_3Mn_2O_7 along arbitrary orientations. The detailed anisotropic characteristics of these parameters were presented. The results reveal the orientation related elastic properties in mm2 point group orthorhombic Ca_3Mn_2O_7.
基金Funded by Key Project of Natural Science for Education Department of Sichuan Province(No.14ZA0102)State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials,Southwest University of Science and Technology,Mianyang
文摘New phosphors Sr2ZnSi2O7： M （M=Mn2＋, Tb3＋） were synthesized through solid-state reaction, and their photoluminescent properties under UV and VUV region were investigated. The results showed that Sr2ZnSi2O7：Mn2＋ emitted green light with the strongest emission peak centered at 525 nm, and its quenching concentration under 254 and 147 nm excitation occurred at x = 0.08 and 0.06, respectively. Sr2ZnSi2O7： Th3＋ emitted green light with the strongest emission peak centered at 541 nm, and its quenching concentration under 254 and 147 nm excitation also appeared at y = 0.25. At 147 nm excitation, the emission intensities of Sr2Zn0.54Si2O7： 0.06Mn2＋ and Sr1.75ZnSi2O7： 0.25Tb3＋ phosphors were 54% and 36% of that of Zn1.96SiO4：0.04Mn2＋, respectively. And their decay times （τ1/e） were about 3.18 ms and 3.9 ms, respectively.
文摘ZHOU Bai-Bin *,1,2 WEI Yong-De 1 LI Zhong-Hua 1 ( 1 Department of Applied Chemistry,Ha rbin Institute of Technology ￡?Harbin￡±￡ì￡°￡°￡°￡±￡(c)( 2 Department of Chemistry,Harbin Normal University￡?Harbin￡±￡ì￡°￡°￡?￡°￡(c) The air-solid interface reaction of Ce,Lu with K10 H 3[Gd (SiMo 4 W￡*O￡3￡1￡(c) 2]through chemistry-heated permeation is reported for the fi rst time￡(r)The permeated complex is characterized by ICP and the result shows tha t the mini mum Ce,Lu can permeate into the inner sph ere of K 10 H ￡3 ￡?Gd ￡¨SiMo ￡′ W ￡* O ￡3￡1 ￡(c) 2]The IR ,XRD patterns give the eviden ce that after permeation the comple x still keeps the Keggin structure,howe ver,its crystal structure is different from the complex before permeation￡(r)The cond uctivity of the permeated complex has been measured with the four-electr ode method and the data show that the co nductivity of the complex after permeation is 10 6 times higher than that of the sample before permeation and reaches ￡′￡(r)84 6×10 -1 S·cm -1 ￡(r)These indicate that the permeated c omplex is a good solid electrolyte and further appli cations are also expected￡(r)
基金the National Natural Science Foundation of China(Grant No.51272027)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20100006110011)
文摘A single-phased silicate compound （Ba1-xCex）9（Sc1-yMny）2Si6O24 was prepared by solid-state reaction at high temperature. From powder X-ray diffraction （XRD） analysis, the formation of Ba9Sc2Si6O24 with an R3 space group was confirmed. In the photoluminescence spectra under ultraviolet （UV） ray excitation, the Ba9Sc2Si6O24：Ce3＋,Mn2＋ phosphor emits two distinctive color light bands： a blue one originating from Ce3＋and a red one caused by Mn2＋. The energy transfer process from Ce3＋ to Mn2＋ was confirmed, the critical radius as well as the transfer efficiency was calculated, and the energy transfer mechanism was discussed. In addition, the decay-time testing indicates that the energy transfer efficiencies from Ce（1） to Mn2＋ and Ce（2） to Mn2＋ are different. The emission chromaticity of Ba9Sc2Si6O24：Ce3＋,Mn2＋ phosphor could be tuned from blue to red by altering the Ce3＋/Mn2＋ concentration ratio.
