The phosphors(Ce 0 67 Tb 0 33 )MgAl 11 O 19 (P G) and BaMgAl 10 O 17 ∶Eu 2+ (P B) have been synthesized using the microwave irradiation technique. The data of X ray powder diffraction...The phosphors(Ce 0 67 Tb 0 33 )MgAl 11 O 19 (P G) and BaMgAl 10 O 17 ∶Eu 2+ (P B) have been synthesized using the microwave irradiation technique. The data of X ray powder diffraction( d values and I/I 0 values) are basically coincided with the data of JCPDF 36 73 and 26 163 cards. The calculated cell dimensions are a =0 5582 nm, c =2 1884 nm for P G, and a =0 5616 nm, c =2 2614 nm for P B. The excitation spectra and the emission spectra of the phosphors were measured. The chromatic coordinates are x =0 316, y =0 565 for P G, and x =0 156, y =0 106 for P B. The relative luminescent intensity is about 88%(P G) and 80%(P B), respectively, compared with the same commercial phosphors. The phosphors were also detected by scanning election microscope.展开更多
The phosphor Y2O2S:Eu3+ powder crystal has been synthesized by using the microwave thermal method.The data of X-ray powder diffraction showed that the phosphor structure belongs to hexagonal system with lattice parame...The phosphor Y2O2S:Eu3+ powder crystal has been synthesized by using the microwave thermal method.The data of X-ray powder diffraction showed that the phosphor structure belongs to hexagonal system with lattice parameters a=0.3785 nm,c=0.6590nm.The excitation spectrum of the phosphor is a broad band with peak at λ(ex)= 261 nm.The main emission peak at λ(em)=626nm and the other emission lines peak at 595,617 and 706 nm are assigned to transitions of the Eu3+ respectively.Under 254 nm excitation,the chromatic coordinates of phosphor are x=0.665, y=0.330.The relative luminescent intensity is about 62% compared with the standard phosphor Y2O3:Eu3+.Under 365nm excitation this phosphor gives rise to an intense red light.The phosphor particle size has a medium diameter of 7.3μm.展开更多
Fluorescence interferometry is developed and applied to study ultrafast amplitude and phase dynamics for fleeinduction decay in powdered rare earth solids. The time-resolved phase dynamics of free-induction decay thro...Fluorescence interferometry is developed and applied to study ultrafast amplitude and phase dynamics for fleeinduction decay in powdered rare earth solids. The time-resolved phase dynamics of free-induction decay throughout the decaying process is accurately determined by using a novel dual-channel correlation technique and subpicosecond dephasing time is measured for Nd3+ solids at room temperature. The phase dynamics is well simulated with linear coherent polarization theory.展开更多
The dark matter puzzle is one of the most important fundamental physics questions in the 21st century.There is no doubt that solving the puzzle will be a new milestone for human beings in achieving a deeper understand...The dark matter puzzle is one of the most important fundamental physics questions in the 21st century.There is no doubt that solving the puzzle will be a new milestone for human beings in achieving a deeper understanding of nature.Herein,we propose the use of the Shanghai laser electron gamma source(SLEGS)to search for dark matter candidate particles,including dark pseudoscalar particles,dark scalar particles,and dark photons.Our simulations indicate that,with some upgrading,electron facilities such as SLEGS could be competitive platforms in the search for light dark matter particles with a mass below tens of keV.展开更多
文摘The phosphors(Ce 0 67 Tb 0 33 )MgAl 11 O 19 (P G) and BaMgAl 10 O 17 ∶Eu 2+ (P B) have been synthesized using the microwave irradiation technique. The data of X ray powder diffraction( d values and I/I 0 values) are basically coincided with the data of JCPDF 36 73 and 26 163 cards. The calculated cell dimensions are a =0 5582 nm, c =2 1884 nm for P G, and a =0 5616 nm, c =2 2614 nm for P B. The excitation spectra and the emission spectra of the phosphors were measured. The chromatic coordinates are x =0 316, y =0 565 for P G, and x =0 156, y =0 106 for P B. The relative luminescent intensity is about 88%(P G) and 80%(P B), respectively, compared with the same commercial phosphors. The phosphors were also detected by scanning election microscope.
文摘The phosphor Y2O2S:Eu3+ powder crystal has been synthesized by using the microwave thermal method.The data of X-ray powder diffraction showed that the phosphor structure belongs to hexagonal system with lattice parameters a=0.3785 nm,c=0.6590nm.The excitation spectrum of the phosphor is a broad band with peak at λ(ex)= 261 nm.The main emission peak at λ(em)=626nm and the other emission lines peak at 595,617 and 706 nm are assigned to transitions of the Eu3+ respectively.Under 254 nm excitation,the chromatic coordinates of phosphor are x=0.665, y=0.330.The relative luminescent intensity is about 62% compared with the standard phosphor Y2O3:Eu3+.Under 365nm excitation this phosphor gives rise to an intense red light.The phosphor particle size has a medium diameter of 7.3μm.
基金Supported by the National Natural Science Foundation of China under Grant No.29673058Ministry of Education under GrantNo.97055803and Natural Science Foundation of Guangdong under Grant No.970146.
文摘Fluorescence interferometry is developed and applied to study ultrafast amplitude and phase dynamics for fleeinduction decay in powdered rare earth solids. The time-resolved phase dynamics of free-induction decay throughout the decaying process is accurately determined by using a novel dual-channel correlation technique and subpicosecond dephasing time is measured for Nd3+ solids at room temperature. The phase dynamics is well simulated with linear coherent polarization theory.
基金Supported by the National Nature Science Foundation of China(11875191,11775140)the Strategic Priority Research Program(CAS XDB1602)。
文摘The dark matter puzzle is one of the most important fundamental physics questions in the 21st century.There is no doubt that solving the puzzle will be a new milestone for human beings in achieving a deeper understanding of nature.Herein,we propose the use of the Shanghai laser electron gamma source(SLEGS)to search for dark matter candidate particles,including dark pseudoscalar particles,dark scalar particles,and dark photons.Our simulations indicate that,with some upgrading,electron facilities such as SLEGS could be competitive platforms in the search for light dark matter particles with a mass below tens of keV.
