The CaS∶Eu^(2+), Sm^(3+) powders were prepared by high-temperature solid method in a reducing atmosphere. The influences of temperature and fired-time on properties of samples were studied. XRD analysis shows that cr...The CaS∶Eu^(2+), Sm^(3+) powders were prepared by high-temperature solid method in a reducing atmosphere. The influences of temperature and fired-time on properties of samples were studied. XRD analysis shows that crystal structure of CaS has formed at 700 ℃. Spectrum analysis results show that the samples which were stimulated by 980 nm laser after excited by ultraviolet lamp emit red luminescence peaking at 649 nm.展开更多
Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results du...Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.展开更多
Before and after X-irradiation, two photon spectral hole burning experiments in BaF (Cl,Br) : Sm2+ were performed by a 560 nm laser light at liquid nitrogen temperature. The results show that spectral hole burning of ...Before and after X-irradiation, two photon spectral hole burning experiments in BaF (Cl,Br) : Sm2+ were performed by a 560 nm laser light at liquid nitrogen temperature. The results show that spectral hole burning of Sm2+ doped fluoride halide mixed crystals are accompanied by photostimulated luminescence process. This process make hole burning efficiency decreased.展开更多
It is assumed from the energy level that ultraviolet (UV) photons may have intensifying effect on BaFBr∶Eu 2+. In this paper, effect of UV photons (220～290 nm) on the PSL intensity of X-ray irradiated BaFBr∶Eu 2+...It is assumed from the energy level that ultraviolet (UV) photons may have intensifying effect on BaFBr∶Eu 2+. In this paper, effect of UV photons (220～290 nm) on the PSL intensity of X-ray irradiated BaFBr∶Eu 2+ was measured and compared to that on the PSL intensity of 220 nm photons irradiated BaFBr∶Eu 2+. It was found that after the excitation of UV photons the PSL intensity of X-ray irradiated samples decreases least at 250 nm and that of 220 nm photons irradiated samples increases most at 250 nm. When the irradiation sources are X-rays and 220 nm photons the excited electrons are photoelectron and thermal-electrons, respectively, and they have different possibility of being captured by electron traps or combined with luminescent centers. And the peak at 250 nm can be explained with the model of electrons tunneling. It is assumed that the electrons excited by 250 nm have the most possibility of tunneling.展开更多
应用电子束辐照可以揭示载流子注入的半导体器件的电子注入对残余杂质和结构性缺陷的效应影响,对辐照引起改性的研究也十分重要。本文主要研究1.5Me V电子加速器、3Me V电子加速器、7.5Me V电子加速器、7.5Me V电子加速器X射线转靶几种...应用电子束辐照可以揭示载流子注入的半导体器件的电子注入对残余杂质和结构性缺陷的效应影响,对辐照引起改性的研究也十分重要。本文主要研究1.5Me V电子加速器、3Me V电子加速器、7.5Me V电子加速器、7.5Me V电子加速器X射线转靶几种电子束辐照对Al Ga In P材料LED发光性能的影响,并应用PL谱对比分析不同能量和剂量的电子束辐照对Al Ga In P材料LED外延片的辐照效应。在发光强度的变化上,在10k Gy剂量以下的1.5Me V电子束辐照和5k Gy剂量以下的3Me V电子束辐照下,辐照效应使发光强度增强,并随着剂量的增加,发光强度逐渐降低。本实验结果将被用于指导Al Ga In P材料LED的辐照改性实验。展开更多
In this study we are reporting annealing induced optical properties of bismuth ferrite (BiFeO3) thin films deposited on glass substrate via spin coating at 5000 rpm. The structural, optical and surface morphology of B...In this study we are reporting annealing induced optical properties of bismuth ferrite (BiFeO3) thin films deposited on glass substrate via spin coating at 5000 rpm. The structural, optical and surface morphology of BiFeO3 (BFO) thin films have been studied via X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Optical absorption (UV-Vis) and Photoluminescence (PL) spectroscopy. XRD spectra confirm annealing induced phase formation of BiFeO3 possessing a rhombohedral R3c structure. The films are dense and without cracks, although the presence of porosity in BFO/glass was observed. Moreover, optical absorption spectra indicate annealing induced effect on the energy band structure in comparison to pristine BiFeO3. It is observed that annealing effect shows an intense shift in the UV-Vis spectra as diffuse absorption together with the variation in the optical band gap. The evaluated optical band gap values are approximately equal to the bulk band gap value of BiFeO3.展开更多
A series of europium(III) complexes with different chain length, tris [2-m-pyridylmethanamido-5-phenyl- (1,3,4)-oxadiazole] mono [2-(4-n-alkylphenyl)-iminazole (4,5-f)-1,10-phenanthroline] Eu(III) [Eu(PMA)3Nn (n = 6, ...A series of europium(III) complexes with different chain length, tris [2-m-pyridylmethanamido-5-phenyl- (1,3,4)-oxadiazole] mono [2-(4-n-alkylphenyl)-iminazole (4,5-f)-1,10-phenanthroline] Eu(III) [Eu(PMA)3Nn (n = 6, 10, 14,18)] were synthesized. All of these amphiphilic europium(III) complexes could form stable Langmuir film at air/water interface and could be transferred onto hydrophilic quartz and mica substrates by measurement of UV spectra in which the absorbance of the LB films at about 288 nm scales showed the linearity with the number of layers deposited. In order to investigate relation between fluorescence properties and the arrangement of molecular in LB films, surface topography of monolayer films were observed by atomic force microscopy (AFM). Results showed that the emission spectra have Eu(III) characteristic peaks and strong emission strength. It is interesting that the molecular with looser arrangement in LB films has better monochromacity, which illustrated that energy might transferred more easily from ligand to Eu(III) in loosen structure films.展开更多
文摘The CaS∶Eu^(2+), Sm^(3+) powders were prepared by high-temperature solid method in a reducing atmosphere. The influences of temperature and fired-time on properties of samples were studied. XRD analysis shows that crystal structure of CaS has formed at 700 ℃. Spectrum analysis results show that the samples which were stimulated by 980 nm laser after excited by ultraviolet lamp emit red luminescence peaking at 649 nm.
文摘Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.
文摘Before and after X-irradiation, two photon spectral hole burning experiments in BaF (Cl,Br) : Sm2+ were performed by a 560 nm laser light at liquid nitrogen temperature. The results show that spectral hole burning of Sm2+ doped fluoride halide mixed crystals are accompanied by photostimulated luminescence process. This process make hole burning efficiency decreased.
文摘It is assumed from the energy level that ultraviolet (UV) photons may have intensifying effect on BaFBr∶Eu 2+. In this paper, effect of UV photons (220～290 nm) on the PSL intensity of X-ray irradiated BaFBr∶Eu 2+ was measured and compared to that on the PSL intensity of 220 nm photons irradiated BaFBr∶Eu 2+. It was found that after the excitation of UV photons the PSL intensity of X-ray irradiated samples decreases least at 250 nm and that of 220 nm photons irradiated samples increases most at 250 nm. When the irradiation sources are X-rays and 220 nm photons the excited electrons are photoelectron and thermal-electrons, respectively, and they have different possibility of being captured by electron traps or combined with luminescent centers. And the peak at 250 nm can be explained with the model of electrons tunneling. It is assumed that the electrons excited by 250 nm have the most possibility of tunneling.
文摘应用电子束辐照可以揭示载流子注入的半导体器件的电子注入对残余杂质和结构性缺陷的效应影响,对辐照引起改性的研究也十分重要。本文主要研究1.5Me V电子加速器、3Me V电子加速器、7.5Me V电子加速器、7.5Me V电子加速器X射线转靶几种电子束辐照对Al Ga In P材料LED发光性能的影响,并应用PL谱对比分析不同能量和剂量的电子束辐照对Al Ga In P材料LED外延片的辐照效应。在发光强度的变化上,在10k Gy剂量以下的1.5Me V电子束辐照和5k Gy剂量以下的3Me V电子束辐照下,辐照效应使发光强度增强,并随着剂量的增加,发光强度逐渐降低。本实验结果将被用于指导Al Ga In P材料LED的辐照改性实验。
文摘In this study we are reporting annealing induced optical properties of bismuth ferrite (BiFeO3) thin films deposited on glass substrate via spin coating at 5000 rpm. The structural, optical and surface morphology of BiFeO3 (BFO) thin films have been studied via X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Optical absorption (UV-Vis) and Photoluminescence (PL) spectroscopy. XRD spectra confirm annealing induced phase formation of BiFeO3 possessing a rhombohedral R3c structure. The films are dense and without cracks, although the presence of porosity in BFO/glass was observed. Moreover, optical absorption spectra indicate annealing induced effect on the energy band structure in comparison to pristine BiFeO3. It is observed that annealing effect shows an intense shift in the UV-Vis spectra as diffuse absorption together with the variation in the optical band gap. The evaluated optical band gap values are approximately equal to the bulk band gap value of BiFeO3.
文摘A series of europium(III) complexes with different chain length, tris [2-m-pyridylmethanamido-5-phenyl- (1,3,4)-oxadiazole] mono [2-(4-n-alkylphenyl)-iminazole (4,5-f)-1,10-phenanthroline] Eu(III) [Eu(PMA)3Nn (n = 6, 10, 14,18)] were synthesized. All of these amphiphilic europium(III) complexes could form stable Langmuir film at air/water interface and could be transferred onto hydrophilic quartz and mica substrates by measurement of UV spectra in which the absorbance of the LB films at about 288 nm scales showed the linearity with the number of layers deposited. In order to investigate relation between fluorescence properties and the arrangement of molecular in LB films, surface topography of monolayer films were observed by atomic force microscopy (AFM). Results showed that the emission spectra have Eu(III) characteristic peaks and strong emission strength. It is interesting that the molecular with looser arrangement in LB films has better monochromacity, which illustrated that energy might transferred more easily from ligand to Eu(III) in loosen structure films.
