Rare earth-doped inorganic compounds contribute mostly to the family of persistent luminescent materials due to the versatile energy levels of rare earth ions.One of the key research aims is to match the trap level st...Rare earth-doped inorganic compounds contribute mostly to the family of persistent luminescent materials due to the versatile energy levels of rare earth ions.One of the key research aims is to match the trap level stemming from the doped rare earth ion or intrinsic defects to the electronic structure of the host,and therefore thermoluminescence measurement becomes a radical technology in studying trap depth,which is one of the significant parameters that determine the properties of persistent luminescence and photostimulated luminescence.However,the results of trap depth obtained by different thermoluminescence methods are quite different so that they are not comparable.Herein,we analyzed different thermoluminescence methods,selected and improved the traditional peak position method of T_(m)/500 to be E=(-0.94Inβ+30.09)kT_(m).Only the experimental heating rate(β)is needed additionally,but the accuracy is improved greatly in most cases.This convenient and accurate method will accelerate the discovery of novel rare earth-doped materials.展开更多
The mainly characteristic of trapping materials is the trap depth. So it is significant to calculate the trap depth for the trapping materials. A new method of calculating trap depth, which is based on energy band and...The mainly characteristic of trapping materials is the trap depth. So it is significant to calculate the trap depth for the trapping materials. A new method of calculating trap depth, which is based on energy band and using rate equations to analyze thermoluminescence, was brought forward. This method which uses the rate equations of the process and the thermoluminescence curve can replace traditional methods such as first order or second order kinetics. The trap depth of SrAl2O4：Eu^2＋ , Dy^3＋ and Sr4Al14O25：Eu^2＋ , Dy^3＋ was estimated from the glow curve. Then the numerical solution of the trap depth can be obtained. From the results of experiments and calculations, this method can accurately indicate the whole process.展开更多
Thermo-luminescence （TL） is a kind of luminescence decay measured with varying temperature. In the process of TL the decay parameter itself involves the temperature effect of traps. Thus the trap depth is inseparabl...Thermo-luminescence （TL） is a kind of luminescence decay measured with varying temperature. In the process of TL the decay parameter itself involves the temperature effect of traps. Thus the trap depth is inseparable from the decay parameter. There are two separate peaks in the TL curve of ZnS：Cu,Co if the measurement starts from liquid nitrogen temperature. In the experiment we started from zero Celsius temperature to isolate the deeper traps. We have proposed and realized three methods for simultaneous determination of trap depth and decay parameter based on the quasi-equilibrium model and experimental data. If we treat the case of kinetic order a = 1 as a = 2, the error might be as large as 100%.展开更多
For the last few decades,there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped.Most of the established persistent luminescence(PersL)mate...For the last few decades,there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped.Most of the established persistent luminescence(PersL)materials emit light in the visible part of the spectrum;however,in recent years,there has been a growing interest in UV-emitting persistent phosphors in recent years.These materials have been tested for various applications,such as photocatalysis,sterilization,and anti-counterfeiting,among others.Here,we report on the X-ray and UV-activated UV-A long PersL of Ce^(3+)-doped Sr_(3)MgSi_(2)O_(8) material.We prepared samples with varied Ce^(3+)concentrations using solid-state reaction synthesis in an ambient atmosphere and conducted a thorough investigation using photoluminescence(PL),electron paramagnetic resonance(EPR),and thermally stimulated luminescence(TSL)spectroscopy methods.Our experiments show that the PersL signal of Ce^(3+)in the 300-450 nm range can be detected for at least 16 h when samples are irradiated with X-rays or UV.The TSL analysis reveals multiple discrete charge traps in the material with activation energies between 0.5 and 1.7 eV.Further EPR measurements confirm the presence of four paramagnetic centers.The thermal stability of these centers was analyzed,and it is established that one of these centers(g_(1)=2.0056,g_(2)=1.9981,and g_(3)=1.9926)gradually decays at room temperature,which is correlated with the PersL processes.展开更多
Micromotion induced by the radio-frequency field contributes greatly to the systematic frequency shifts of optical frequency standards.Although different strategies for mitigating this effect have been proposed,trappi...Micromotion induced by the radio-frequency field contributes greatly to the systematic frequency shifts of optical frequency standards.Although different strategies for mitigating this effect have been proposed,trapping ions optically has the potential to provide a generic solution to the elimination of micromotion.This could be achieved by trapping a single ion in the dipole trap composed of a highpower laser field.Here,we present the setup of the dipole trap composed of a 532 nm laser at a power of 10 W aiming to optically trap a single^(40)Ca^(+)and we observe an AC-Stark shift of the fluorescence spectrum line of~22 MHz caused by the 532 nm dipole beam.The beam waist of the dipole laser is several microns,which would provide a dipole potential strong enough for all-optical trapping of a single^(40)Ca^(+)ion.展开更多
Fluid inclusions have recorded the history of degassing in basalt. Some fluid inclusions in olivine and pyroxene phenocrysts of basalt were analyzed by micro-thermometry and Raman spectroscopy in this paper. The exper...Fluid inclusions have recorded the history of degassing in basalt. Some fluid inclusions in olivine and pyroxene phenocrysts of basalt were analyzed by micro-thermometry and Raman spectroscopy in this paper. The experimental results showed that many inclusions are present almost in a pure CO2 system. The densities of some CO2 inclusions were computed in terms of Raman spectroscopic characteristics of CO2 Fermi resonance at room temperature. Their densities change over a wide range, but mainly between 0.044 g/cm3 and 0.289 g/cm3. Their micro-thermometric measurements showed that the CO2 inclusions examined reached homogenization between 1145.5℃ and 1265℃ . The mean value of homogenization temperatures of CO2 inclusions in basalts is near 1210℃. The trap pressures (depths) of inclusions were computed with the equation of state and computer program. Distribution of the trap depths makes it know that the degassing of magma can happen over a wide pressure (depth) range, but mainly at the depth of 0.48 km to 3.85 km. This implicates that basalt magma experienced intensive degassing and the CO2 gas reservoir from the basalt magma also may be formed in this range of depths. The results of this study showed that the depth of basalt magma degassing can be forecasted from CO2 fluid inclusions, and it is meaningful for understanding the process of magma degassing and constraining the inorganogenic CO2 gas reservoir.展开更多
基金Project supported by the National Natural Science Foundation of China(52372134,12274023)the Fundamental Re search Funds for the Central Universities(FRF-EYIT-23-04)。
文摘Rare earth-doped inorganic compounds contribute mostly to the family of persistent luminescent materials due to the versatile energy levels of rare earth ions.One of the key research aims is to match the trap level stemming from the doped rare earth ion or intrinsic defects to the electronic structure of the host,and therefore thermoluminescence measurement becomes a radical technology in studying trap depth,which is one of the significant parameters that determine the properties of persistent luminescence and photostimulated luminescence.However,the results of trap depth obtained by different thermoluminescence methods are quite different so that they are not comparable.Herein,we analyzed different thermoluminescence methods,selected and improved the traditional peak position method of T_(m)/500 to be E=(-0.94Inβ+30.09)kT_(m).Only the experimental heating rate(β)is needed additionally,but the accuracy is improved greatly in most cases.This convenient and accurate method will accelerate the discovery of novel rare earth-doped materials.
文摘The mainly characteristic of trapping materials is the trap depth. So it is significant to calculate the trap depth for the trapping materials. A new method of calculating trap depth, which is based on energy band and using rate equations to analyze thermoluminescence, was brought forward. This method which uses the rate equations of the process and the thermoluminescence curve can replace traditional methods such as first order or second order kinetics. The trap depth of SrAl2O4：Eu^2＋ , Dy^3＋ and Sr4Al14O25：Eu^2＋ , Dy^3＋ was estimated from the glow curve. Then the numerical solution of the trap depth can be obtained. From the results of experiments and calculations, this method can accurately indicate the whole process.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10374001, 10434030 and 60576016）, the State Key Development Program for Basic Research of China （Grant No 2003CB314707）, the Excellent Doctor＇s Science and Technology Innovation Foundation of Beijing Jiaotong University （Grant No 48011）, Russian Foundation of Basic Research （Grant Nos 04-02- 16942 and 02-02-39007）.
文摘Thermo-luminescence （TL） is a kind of luminescence decay measured with varying temperature. In the process of TL the decay parameter itself involves the temperature effect of traps. Thus the trap depth is inseparable from the decay parameter. There are two separate peaks in the TL curve of ZnS：Cu,Co if the measurement starts from liquid nitrogen temperature. In the experiment we started from zero Celsius temperature to isolate the deeper traps. We have proposed and realized three methods for simultaneous determination of trap depth and decay parameter based on the quasi-equilibrium model and experimental data. If we treat the case of kinetic order a = 1 as a = 2, the error might be as large as 100%.
基金supported by the Latvian Council of Science,project"Defect engineering of novel UV-C persistent phosphor materials"(lzp-2021/1-0118)。
文摘For the last few decades,there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped.Most of the established persistent luminescence(PersL)materials emit light in the visible part of the spectrum;however,in recent years,there has been a growing interest in UV-emitting persistent phosphors in recent years.These materials have been tested for various applications,such as photocatalysis,sterilization,and anti-counterfeiting,among others.Here,we report on the X-ray and UV-activated UV-A long PersL of Ce^(3+)-doped Sr_(3)MgSi_(2)O_(8) material.We prepared samples with varied Ce^(3+)concentrations using solid-state reaction synthesis in an ambient atmosphere and conducted a thorough investigation using photoluminescence(PL),electron paramagnetic resonance(EPR),and thermally stimulated luminescence(TSL)spectroscopy methods.Our experiments show that the PersL signal of Ce^(3+)in the 300-450 nm range can be detected for at least 16 h when samples are irradiated with X-rays or UV.The TSL analysis reveals multiple discrete charge traps in the material with activation energies between 0.5 and 1.7 eV.Further EPR measurements confirm the presence of four paramagnetic centers.The thermal stability of these centers was analyzed,and it is established that one of these centers(g_(1)=2.0056,g_(2)=1.9981,and g_(3)=1.9926)gradually decays at room temperature,which is correlated with the PersL processes.
基金the National Key Research and Development Program of China(Grant Nos.2018YFA0307500 and 2017YFA0304401)the National Natural Science Foundation of China(Grant Nos.11634013 and 11774388)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030100)the CAS Youth Innovation Promotion Association(Grant Nos.2018364 and Y201963)the Science Fund for Distinguished Young Scholars of Hubei Province,China(Grant No.2017CFA040)the K.C.Wong Education Foundation(Grant No.GJTD-2019-15).
文摘Micromotion induced by the radio-frequency field contributes greatly to the systematic frequency shifts of optical frequency standards.Although different strategies for mitigating this effect have been proposed,trapping ions optically has the potential to provide a generic solution to the elimination of micromotion.This could be achieved by trapping a single ion in the dipole trap composed of a highpower laser field.Here,we present the setup of the dipole trap composed of a 532 nm laser at a power of 10 W aiming to optically trap a single^(40)Ca^(+)and we observe an AC-Stark shift of the fluorescence spectrum line of~22 MHz caused by the 532 nm dipole beam.The beam waist of the dipole laser is several microns,which would provide a dipole potential strong enough for all-optical trapping of a single^(40)Ca^(+)ion.
文摘Fluid inclusions have recorded the history of degassing in basalt. Some fluid inclusions in olivine and pyroxene phenocrysts of basalt were analyzed by micro-thermometry and Raman spectroscopy in this paper. The experimental results showed that many inclusions are present almost in a pure CO2 system. The densities of some CO2 inclusions were computed in terms of Raman spectroscopic characteristics of CO2 Fermi resonance at room temperature. Their densities change over a wide range, but mainly between 0.044 g/cm3 and 0.289 g/cm3. Their micro-thermometric measurements showed that the CO2 inclusions examined reached homogenization between 1145.5℃ and 1265℃ . The mean value of homogenization temperatures of CO2 inclusions in basalts is near 1210℃. The trap pressures (depths) of inclusions were computed with the equation of state and computer program. Distribution of the trap depths makes it know that the degassing of magma can happen over a wide pressure (depth) range, but mainly at the depth of 0.48 km to 3.85 km. This implicates that basalt magma experienced intensive degassing and the CO2 gas reservoir from the basalt magma also may be formed in this range of depths. The results of this study showed that the depth of basalt magma degassing can be forecasted from CO2 fluid inclusions, and it is meaningful for understanding the process of magma degassing and constraining the inorganogenic CO2 gas reservoir.
