The production of Y2O3-ZrO2 powder by the reaction of zirconium salt and yttrium salt, combined in a certain proportion, with sodium nitrate under molten state was described. The effects of adding Cl-, Br- and CO2-3 a...The production of Y2O3-ZrO2 powder by the reaction of zirconium salt and yttrium salt, combined in a certain proportion, with sodium nitrate under molten state was described. The effects of adding Cl-, Br- and CO2-3 anions, as well as introducing ultrasonic vibration during the reaction on the crystallite size of Y2O3-Zr2O3 powder were investigated.展开更多
In December of 1988, the authors successfully developed a high Jc Y-Ba-Cu-O superconductor tape on a nickel substrate by means of powder rolling. The tape is 0.94mm2 in cross-section and its critical current is 21.0A ...In December of 1988, the authors successfully developed a high Jc Y-Ba-Cu-O superconductor tape on a nickel substrate by means of powder rolling. The tape is 0.94mm2 in cross-section and its critical current is 21.0A at 77K and in zero applied field. The microstructures of the tapes with different Jc were analysed by TEM. The result shows that the tapes with different Jc have different microstructures. From the facts, it can be concluded that making the grain boundary 'clean' might have some effects on the weak-link problem and the twin zone might act as fluxing pinning centers. Therefore, to purify the grain boundary, to thin the twin and to homogenize the microstructure will be of benefit in increasing Jc.展开更多
The far-IR spectra of ML3·H2O (M=Y, La-Lu; HL=o-chlorobenzoic acid) have been studied, and the wavenumbers of M-O vibrations (νM-O) have been assigned. It is found that ν-O increases as the atomic number o...The far-IR spectra of ML3·H2O (M=Y, La-Lu; HL=o-chlorobenzoic acid) have been studied, and the wavenumbers of M-O vibrations (νM-O) have been assigned. It is found that ν-O increases as the atomic number of lanthanide element increase. Moreover, the plot of νM-O-L (L is the total orbital angular quantum number of lanthanide ion in ground state) shows an inclined W systematics.展开更多
Ytterbium-doped yttrium oxysulfide （Yb：Y2O2S） has been synthesized by solid-state reaction with sulfide flux. Diffuse reflection and emission spectra have been measured in order to determine the crystal field split...Ytterbium-doped yttrium oxysulfide （Yb：Y2O2S） has been synthesized by solid-state reaction with sulfide flux. Diffuse reflection and emission spectra have been measured in order to determine the crystal field splitting of Yb^3＋ ion in the YOS lattice. According to the crystal-field levels probed in the spectra, the crystal field splitting of 2F7/2 manifold of Yb^3＋ ion in YOS is 709 cm^-1, which is large enough for the quasi-three-level laser operation of Yb^3＋ ion. Emission peak position, width, full-width at half maximum （FWHM）, and normalized intensity of Yb：YOS are fitted from its emission spectrum. For comparison, relevant data of 5.4 at.-% Yb：YAG is also provided.展开更多
A novel yttrium citrate-templated conversion method for morphology controlled synthesis of Y2O3 microspheres, microflowers and microsheets was reported for the first time. The precursors with controllable morphologies...A novel yttrium citrate-templated conversion method for morphology controlled synthesis of Y2O3 microspheres, microflowers and microsheets was reported for the first time. The precursors with controllable morphologies were synthesized with a homogenous precipitation method in aqueous solution without any surfactant. Y2O3 samples with well-preserved morphological architectures were obtained by a subse-quent thermal transformation strategy. The chemical formula of the precursor was identified and a two-stage growth mechanism was proposed. The effects of the aging time, reaction temperature, reactant concentration and molar ratio of yttrium nitrate to sodium citrate were discussed. The photoluminescence properties of the Y2O3：Eu3＋ microspheres, microflowers and microsheets prepared were also studied.展开更多
A diode-pumped single frequcncy Tm,Ho：YLF laser operating at an eye-safe wavelength of 2 μm has been developed. Temperature of the laser crystal was controlled at room temperature with a thermoelectric cooler. The l...A diode-pumped single frequcncy Tm,Ho：YLF laser operating at an eye-safe wavelength of 2 μm has been developed. Temperature of the laser crystal was controlled at room temperature with a thermoelectric cooler. The line-width narrowing elements were two solid uncoated fused silica etalons whose thicknesses were 1 and 0.1 mm, respectively. Continuous wave single frequency power of 113 mW was obtained.展开更多
The absorption spectra, fluorescence spectra, and lifetimes of as-grown and annealed Cr,Yb:YAG crystal grown by Czochralski technique have been measured. The broad absorption bands in the visible region increase in in...The absorption spectra, fluorescence spectra, and lifetimes of as-grown and annealed Cr,Yb:YAG crystal grown by Czochralski technique have been measured. The broad absorption bands in the visible region increase in intensity and shift to long wavelength after annealing, and the additional absorption around 482 nm may be possibly due to new octahedral Cr4+ center in the crystal, and the increase in the infrared (IR) region is due to the increase of Cr4+. The increase of Cr4+ also results in the groud state absorption and the concentration quenching of Yb3+ in Cr,Yb:YAG crystal after annealing, the fluorescence intensity is reduced to 75% and the emission lifetime is shortened from 1.40 to 0.44 ms.展开更多
To optimize the performance of longitudinally pumped Yb3+:Y2O3 ceramic lasers, cavity parameters such as material length and output coupler transmission at a certain laser output power are calculated numerically using...To optimize the performance of longitudinally pumped Yb3+:Y2O3 ceramic lasers, cavity parameters such as material length and output coupler transmission at a certain laser output power are calculated numerically using quasi-three-level laser model. The results show great potential of Yb3+:Y2O3 ceramics for highly efficient diode-pumped solid-state lasers.展开更多
The phenomena of simultaneous Q-switching and mode-locking in a diode-pumped Nd:YVO4/Cr:YAG/ KTP green laser are reported and discussed in this paper. With 5.3-W pump power, by using a nearly hemispherical cavity (the...The phenomena of simultaneous Q-switching and mode-locking in a diode-pumped Nd:YVO4/Cr:YAG/ KTP green laser are reported and discussed in this paper. With 5.3-W pump power, by using a nearly hemispherical cavity (the cavity length is only 97 mm), the results of modulation depth of 70% and the period of 0.6 ns are obtained, the output power and the repetitive frequency of Q-switched pulse are 90 mW and 12 kHz, respectively.展开更多
文摘The production of Y2O3-ZrO2 powder by the reaction of zirconium salt and yttrium salt, combined in a certain proportion, with sodium nitrate under molten state was described. The effects of adding Cl-, Br- and CO2-3 anions, as well as introducing ultrasonic vibration during the reaction on the crystallite size of Y2O3-Zr2O3 powder were investigated.
文摘In December of 1988, the authors successfully developed a high Jc Y-Ba-Cu-O superconductor tape on a nickel substrate by means of powder rolling. The tape is 0.94mm2 in cross-section and its critical current is 21.0A at 77K and in zero applied field. The microstructures of the tapes with different Jc were analysed by TEM. The result shows that the tapes with different Jc have different microstructures. From the facts, it can be concluded that making the grain boundary 'clean' might have some effects on the weak-link problem and the twin zone might act as fluxing pinning centers. Therefore, to purify the grain boundary, to thin the twin and to homogenize the microstructure will be of benefit in increasing Jc.
文摘The far-IR spectra of ML3·H2O (M=Y, La-Lu; HL=o-chlorobenzoic acid) have been studied, and the wavenumbers of M-O vibrations (νM-O) have been assigned. It is found that ν-O increases as the atomic number of lanthanide element increase. Moreover, the plot of νM-O-L (L is the total orbital angular quantum number of lanthanide ion in ground state) shows an inclined W systematics.
文摘Ytterbium-doped yttrium oxysulfide （Yb：Y2O2S） has been synthesized by solid-state reaction with sulfide flux. Diffuse reflection and emission spectra have been measured in order to determine the crystal field splitting of Yb^3＋ ion in the YOS lattice. According to the crystal-field levels probed in the spectra, the crystal field splitting of 2F7/2 manifold of Yb^3＋ ion in YOS is 709 cm^-1, which is large enough for the quasi-three-level laser operation of Yb^3＋ ion. Emission peak position, width, full-width at half maximum （FWHM）, and normalized intensity of Yb：YOS are fitted from its emission spectrum. For comparison, relevant data of 5.4 at.-% Yb：YAG is also provided.
基金Project supported by the National Natural Science Foundation of China (50990304)State "973" Project (2007CB936704)
文摘A novel yttrium citrate-templated conversion method for morphology controlled synthesis of Y2O3 microspheres, microflowers and microsheets was reported for the first time. The precursors with controllable morphologies were synthesized with a homogenous precipitation method in aqueous solution without any surfactant. Y2O3 samples with well-preserved morphological architectures were obtained by a subse-quent thermal transformation strategy. The chemical formula of the precursor was identified and a two-stage growth mechanism was proposed. The effects of the aging time, reaction temperature, reactant concentration and molar ratio of yttrium nitrate to sodium citrate were discussed. The photoluminescence properties of the Y2O3：Eu3＋ microspheres, microflowers and microsheets prepared were also studied.
基金This work was supported by the Scientic Re-search Foundation of Harbin Engineering Univer-sity (HEUF04014)
文摘A diode-pumped single frequcncy Tm,Ho：YLF laser operating at an eye-safe wavelength of 2 μm has been developed. Temperature of the laser crystal was controlled at room temperature with a thermoelectric cooler. The line-width narrowing elements were two solid uncoated fused silica etalons whose thicknesses were 1 and 0.1 mm, respectively. Continuous wave single frequency power of 113 mW was obtained.
文摘The absorption spectra, fluorescence spectra, and lifetimes of as-grown and annealed Cr,Yb:YAG crystal grown by Czochralski technique have been measured. The broad absorption bands in the visible region increase in intensity and shift to long wavelength after annealing, and the additional absorption around 482 nm may be possibly due to new octahedral Cr4+ center in the crystal, and the increase in the infrared (IR) region is due to the increase of Cr4+. The increase of Cr4+ also results in the groud state absorption and the concentration quenching of Yb3+ in Cr,Yb:YAG crystal after annealing, the fluorescence intensity is reduced to 75% and the emission lifetime is shortened from 1.40 to 0.44 ms.
文摘To optimize the performance of longitudinally pumped Yb3+:Y2O3 ceramic lasers, cavity parameters such as material length and output coupler transmission at a certain laser output power are calculated numerically using quasi-three-level laser model. The results show great potential of Yb3+:Y2O3 ceramics for highly efficient diode-pumped solid-state lasers.
文摘The phenomena of simultaneous Q-switching and mode-locking in a diode-pumped Nd:YVO4/Cr:YAG/ KTP green laser are reported and discussed in this paper. With 5.3-W pump power, by using a nearly hemispherical cavity (the cavity length is only 97 mm), the results of modulation depth of 70% and the period of 0.6 ns are obtained, the output power and the repetitive frequency of Q-switched pulse are 90 mW and 12 kHz, respectively.
