The buffer layer CeO2 films were grown on cube textured metallic Ni substrates by using reactive magnetrun sputtering. Ar/H2 mixed atmosphere, which effectively inhibited the formation of NiO, was used as pre-depositi...The buffer layer CeO2 films were grown on cube textured metallic Ni substrates by using reactive magnetrun sputtering. Ar/H2 mixed atmosphere, which effectively inhibited the formation of NiO, was used as pre-depositing gas before CeO2 films were grown in Ar and 02. At 700 ℃ under the total pressure of 26 Pa,the pure c-axis orientation tilm was obtained. X-ray θ-2θscan, pole figure and φ-scan were used to observe the microstructure of the buffer layer. The resuits show that CeO2 film has strong cube texture and the FWHM is 9°. In addition, the CeO2 film is dense and crack-free.展开更多
Two groups of coated conductor samples with different thicknesses of CeO2 cap layers deposited by pulsed laser deposition （PLD） under the same conditions have been studied. Of them, one group is of CeO2 films, which...Two groups of coated conductor samples with different thicknesses of CeO2 cap layers deposited by pulsed laser deposition （PLD） under the same conditions have been studied. Of them, one group is of CeO2 films, which are deposited on stainless steel （SS） tapes coated by IBAD-YSZ （IBAD-YSZ/SS）, and the other group is of CeO2/YSZ/Y2O3 multilayers, which are deposited on NiW substrates by PLD for the fabrication of YBCO-coated conductor through the RABiTS approach. YBCO film is then deposited on the tops of both types of buffer layers by PLD. The effects of the thickness of the CeO2 film on the texture of the CeO2 film and the critical current density （Jc） of the YBCO film are analysed. For the case of CeO2 film on IBAD-YSZ/SS, there appears a self-epitaxy effect with increasing thickness of the CeO2 film. For CeO2/YSZ/Y2O3/NiW, in which the buffer layers are deposited by PLD, there occurs no self-epitaxy effect, and the optimal thickness of CeO2 is about 50 nm. The surface morphologies of the two groups of samples are examined by SEM.展开更多
In this paper, we report a continuous deposition method for double-sided CeO2/YSZ/Y2O3 buffer layers by reel-to-reel in a D.C. magnetron reactive sputtering system. X-ray diffraction exhibited all the samples were hig...In this paper, we report a continuous deposition method for double-sided CeO2/YSZ/Y2O3 buffer layers by reel-to-reel in a D.C. magnetron reactive sputtering system. X-ray diffraction exhibited all the samples were highly c-axis oriented and atomic force microscope observations revealed a smooth, dense and crack-free surface morphology. Out-of-plane, in-plane texture, and surface roughness of multi-buffer layers were improved under optimized deposition conditions. Full width at half maximum (FWHM) values of out-of-plane and in-plane were about 4° and 5.5° in 50 cm double-sided buffed template. YBa2Cu3O7-δ films with thickness of 1.2 μm were deposited on both sides of the buffed tape. Both sides showed similar critical current density, Jc (77 K, self field) as 0.8 MA/cm2 and 0.7 MA/cm2, respectively.展开更多
The CeO2 and Y2O3 buffer layers were deposited on the cube textured metallic Ni substrates by using reactive magnetron sputtering. Ar/H2 mixed atmosphere, which is used as pre-depositing gas, can effectively inhibit t...The CeO2 and Y2O3 buffer layers were deposited on the cube textured metallic Ni substrates by using reactive magnetron sputtering. Ar/H2 mixed atmosphere, which is used as pre-depositing gas, can effectively inhibit the formation of NiO. In addition, the linear relationship between pre-depositing time and total depositing time is required to ensure the epitaxial growth of the films. The growth conditions of CeO2 and Y2O3 were comparatively studied, and it is found that the windows of substrate temperatures and pressures for CeO2 films are wider than that for Y2O3 films.展开更多
The metal organic deposition (MOD) method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer. The material phase and the macro-orienta...The metal organic deposition (MOD) method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer. The material phase and the macro-orientations were analyzed by XRD. The surface morphology and the blocking performance of the buffer layer were investigated by SEM and AES. The grain orientation and the crystallographic growth mode of the CeO2 layer were first characterized by electron backscattering diffraction (EBSD). The uniformly distributed islanded LZO seed layer optimized both the in-plan and the out-plan orientation of the CeO2/LZO buffer layers, and the CeO2/LZO buffer layers with a thickness of 175 nm acted as an efficient Ni,W barrier. The EBSD analysis indicated that the crystallographic orientation of each layer can be obtained at various accelerating voltages for the multilayer sample, the percentage of {001}<110> rotated cube texture of CeO2 layer reaching 97.4% at the accelerating voltage of 15 kV, thus showing epitaxial deposition with a high texture.展开更多
We design and prepare three-layer graded ZnO nanowhisker/polyester composites. The dispersion configuration of ZnO nanowhiskers in the polyester is investigated, and their microwave reflectivity curves are also measur...We design and prepare three-layer graded ZnO nanowhisker/polyester composites. The dispersion configuration of ZnO nanowhiskers in the polyester is investigated, and their microwave reflectivity curves are also measured. Experimental results have shown that the graded dispersion with ZnO nanowhiskers contributes to broadband microwave absorption. In other words, the absorption band depends on the graded dispersion configuration of ZnO nanowhiskers in polyester matrix.展开更多
Two phases of coherent structure motion are acquired after obtaining conditional phase-averaged waveforms for longitudinal velocity of coherent structures in turbulent boundary layer based on Harr wavelet transfer. Th...Two phases of coherent structure motion are acquired after obtaining conditional phase-averaged waveforms for longitudinal velocity of coherent structures in turbulent boundary layer based on Harr wavelet transfer. The correspondences of the two phases to the two processes （i.e. ejection and sweep） during a burst are determined.展开更多
We investigate the boundary-layer flow on a moving permeable plate parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist when the ...We investigate the boundary-layer flow on a moving permeable plate parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist when the plate and the free stream move in the opposite directions.展开更多
We investigate the boundary-layer flow on a moving isothermal thin needle parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist wh...We investigate the boundary-layer flow on a moving isothermal thin needle parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist when the needle and the free stream move in the opposite directions.展开更多
Based on the mechanism of injection, transport and recombination of the charge carriers, we develop a model to calculate the delay time of electroluminescence （EL） from bilayer organic light emitting diodes. The eff...Based on the mechanism of injection, transport and recombination of the charge carriers, we develop a model to calculate the delay time of electroluminescence （EL） from bilayer organic light emitting diodes. The effect of injection, transport and recombination processes on the EL delay time is discussed, and the relationship between the internal interface barrier and the recombination time is revealed. ＂]~he results show that the EL delay time is dominated by the recombination process at lower applied voltage and by the transport process at higher applied voltage. When the internal interface barrier varies from 0.15 eV to 0.3 eV, the recombination delay time increases rapidly~ while the internal interface barrier exceeds about 0.3eV~ the dependence of the recombination delay time on applied voltage is almost undiversified, which may serve as a guideline for designing of a high-speed EL response device.展开更多
Nanocrystalline Si/SiO2 multilayers are prepared by thermally annealing amorphous Si/SiO2 stacked structures. The photoluminescence intensity is obviously enhanced after hydrogen passivation at various temperatures. I...Nanocrystalline Si/SiO2 multilayers are prepared by thermally annealing amorphous Si/SiO2 stacked structures. The photoluminescence intensity is obviously enhanced after hydrogen passivation at various temperatures. It is suggested that the hydrogen trapping and detrapping processes at different temperatures strongly influence the passivation effect. Direct experimental evidence is given by electron spin resonance spectra that hydrogen effectively reduces the nonradiative defect states existing in the Si nanocrystas/SiO2 system which enhances the radiative recombination probability. The luminescence characteristic shows its stability after hydrogen passivation even after aging eight months.展开更多
Research on evolutionary games in a noisy environment is still a non-solved problem. By using Markov process, we build a dynamic model for two-player and two-strategy symmetric game in noisy environment. Some illustra...Research on evolutionary games in a noisy environment is still a non-solved problem. By using Markov process, we build a dynamic model for two-player and two-strategy symmetric game in noisy environment. Some illustrative examples are presented and the results are determined by simulation experiments.展开更多
CeO2 nanowires are successful synthesized by hydrothermal method and their field emission （FE） properties are investigated. The turn-on electric field is 5.8 V/μm at an emitter-anode spacing of 700μm. The FE curre...CeO2 nanowires are successful synthesized by hydrothermal method and their field emission （FE） properties are investigated. The turn-on electric field is 5.8 V/μm at an emitter-anode spacing of 700μm. The FE current is stable and the current fluctuations are less than 3% over 5 h. All the plotted Fowler-Nordheim curves yield straight lines, which are in agreement with the Fowler-Nordheim theory. The relationship between the field enhancement factor β and the emitter-anode spacing d follows a universal equation. Our results imply that the CeO2 nanowires are promising materials for fabricating FE cathodes.展开更多
文摘The buffer layer CeO2 films were grown on cube textured metallic Ni substrates by using reactive magnetrun sputtering. Ar/H2 mixed atmosphere, which effectively inhibited the formation of NiO, was used as pre-depositing gas before CeO2 films were grown in Ar and 02. At 700 ℃ under the total pressure of 26 Pa,the pure c-axis orientation tilm was obtained. X-ray θ-2θscan, pole figure and φ-scan were used to observe the microstructure of the buffer layer. The resuits show that CeO2 film has strong cube texture and the FWHM is 9°. In addition, the CeO2 film is dense and crack-free.
文摘Two groups of coated conductor samples with different thicknesses of CeO2 cap layers deposited by pulsed laser deposition （PLD） under the same conditions have been studied. Of them, one group is of CeO2 films, which are deposited on stainless steel （SS） tapes coated by IBAD-YSZ （IBAD-YSZ/SS）, and the other group is of CeO2/YSZ/Y2O3 multilayers, which are deposited on NiW substrates by PLD for the fabrication of YBCO-coated conductor through the RABiTS approach. YBCO film is then deposited on the tops of both types of buffer layers by PLD. The effects of the thickness of the CeO2 film on the texture of the CeO2 film and the critical current density （Jc） of the YBCO film are analysed. For the case of CeO2 film on IBAD-YSZ/SS, there appears a self-epitaxy effect with increasing thickness of the CeO2 film. For CeO2/YSZ/Y2O3/NiW, in which the buffer layers are deposited by PLD, there occurs no self-epitaxy effect, and the optimal thickness of CeO2 is about 50 nm. The surface morphologies of the two groups of samples are examined by SEM.
文摘In this paper, we report a continuous deposition method for double-sided CeO2/YSZ/Y2O3 buffer layers by reel-to-reel in a D.C. magnetron reactive sputtering system. X-ray diffraction exhibited all the samples were highly c-axis oriented and atomic force microscope observations revealed a smooth, dense and crack-free surface morphology. Out-of-plane, in-plane texture, and surface roughness of multi-buffer layers were improved under optimized deposition conditions. Full width at half maximum (FWHM) values of out-of-plane and in-plane were about 4° and 5.5° in 50 cm double-sided buffed template. YBa2Cu3O7-δ films with thickness of 1.2 μm were deposited on both sides of the buffed tape. Both sides showed similar critical current density, Jc (77 K, self field) as 0.8 MA/cm2 and 0.7 MA/cm2, respectively.
文摘The CeO2 and Y2O3 buffer layers were deposited on the cube textured metallic Ni substrates by using reactive magnetron sputtering. Ar/H2 mixed atmosphere, which is used as pre-depositing gas, can effectively inhibit the formation of NiO. In addition, the linear relationship between pre-depositing time and total depositing time is required to ensure the epitaxial growth of the films. The growth conditions of CeO2 and Y2O3 were comparatively studied, and it is found that the windows of substrate temperatures and pressures for CeO2 films are wider than that for Y2O3 films.
基金National Basic Research Program "973" of China (2006CB601005)National Natural Science Foundation of China (50771003)National High Technology Research and Development Program of "863" (2009AA032401)
文摘The metal organic deposition (MOD) method was used for the epitaxial growth of the CeO2/La2Zr2O7(LZO)/LZO seed layer structure on a cube-textured Ni5W substrate layer by layer. The material phase and the macro-orientations were analyzed by XRD. The surface morphology and the blocking performance of the buffer layer were investigated by SEM and AES. The grain orientation and the crystallographic growth mode of the CeO2 layer were first characterized by electron backscattering diffraction (EBSD). The uniformly distributed islanded LZO seed layer optimized both the in-plan and the out-plan orientation of the CeO2/LZO buffer layers, and the CeO2/LZO buffer layers with a thickness of 175 nm acted as an efficient Ni,W barrier. The EBSD analysis indicated that the crystallographic orientation of each layer can be obtained at various accelerating voltages for the multilayer sample, the percentage of {001}<110> rotated cube texture of CeO2 layer reaching 97.4% at the accelerating voltage of 15 kV, thus showing epitaxial deposition with a high texture.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50572010, 50742007 and 10672020, the National Defense Founds of China under Grant Nos A2220061080, and the National Key Basic Research Programme of China under Grant No 5131803.
文摘We design and prepare three-layer graded ZnO nanowhisker/polyester composites. The dispersion configuration of ZnO nanowhiskers in the polyester is investigated, and their microwave reflectivity curves are also measured. Experimental results have shown that the graded dispersion with ZnO nanowhiskers contributes to broadband microwave absorption. In other words, the absorption band depends on the graded dispersion configuration of ZnO nanowhiskers in polyester matrix.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10472081 and 10232020.
文摘Two phases of coherent structure motion are acquired after obtaining conditional phase-averaged waveforms for longitudinal velocity of coherent structures in turbulent boundary layer based on Harr wavelet transfer. The correspondences of the two phases to the two processes （i.e. ejection and sweep） during a burst are determined.
文摘We investigate the boundary-layer flow on a moving permeable plate parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist when the plate and the free stream move in the opposite directions.
文摘We investigate the boundary-layer flow on a moving isothermal thin needle parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist when the needle and the free stream move in the opposite directions.
基金Supported by the Distinguished Youth Foundation of Hunan Province under Grant No 0333Y1008, the Science Foundation for Post doctorate of China under Grant No 2004035083, the Natural Science Foundation of Hunan Province under Grant No 063320034, and the Science Foundation of Central South University under Grant No 0601059.
文摘Based on the mechanism of injection, transport and recombination of the charge carriers, we develop a model to calculate the delay time of electroluminescence （EL） from bilayer organic light emitting diodes. The effect of injection, transport and recombination processes on the EL delay time is discussed, and the relationship between the internal interface barrier and the recombination time is revealed. ＂]~he results show that the EL delay time is dominated by the recombination process at lower applied voltage and by the transport process at higher applied voltage. When the internal interface barrier varies from 0.15 eV to 0.3 eV, the recombination delay time increases rapidly~ while the internal interface barrier exceeds about 0.3eV~ the dependence of the recombination delay time on applied voltage is almost undiversified, which may serve as a guideline for designing of a high-speed EL response device.
基金Supported by the National Natural Science Foundation of China under Nos 60425414, 50472066, 90301009 and 10574069, the Natural Science Foundation of Jiangsu Province （BK2006715）, and the National Basic Research Programme of China under Grant No 2007CB613401.
文摘Nanocrystalline Si/SiO2 multilayers are prepared by thermally annealing amorphous Si/SiO2 stacked structures. The photoluminescence intensity is obviously enhanced after hydrogen passivation at various temperatures. It is suggested that the hydrogen trapping and detrapping processes at different temperatures strongly influence the passivation effect. Direct experimental evidence is given by electron spin resonance spectra that hydrogen effectively reduces the nonradiative defect states existing in the Si nanocrystas/SiO2 system which enhances the radiative recombination probability. The luminescence characteristic shows its stability after hydrogen passivation even after aging eight months.
基金Supported by the National Natural Science Foundation of China under Grant No 60574071.
文摘Research on evolutionary games in a noisy environment is still a non-solved problem. By using Markov process, we build a dynamic model for two-player and two-strategy symmetric game in noisy environment. Some illustrative examples are presented and the results are determined by simulation experiments.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60236010, 60571044, and 90606009, the Ministry of Education under Grant No 705040, and the Special Funds for Major State Basic Research Project of China under Grant No G2001CB3095.
文摘CeO2 nanowires are successful synthesized by hydrothermal method and their field emission （FE） properties are investigated. The turn-on electric field is 5.8 V/μm at an emitter-anode spacing of 700μm. The FE current is stable and the current fluctuations are less than 3% over 5 h. All the plotted Fowler-Nordheim curves yield straight lines, which are in agreement with the Fowler-Nordheim theory. The relationship between the field enhancement factor β and the emitter-anode spacing d follows a universal equation. Our results imply that the CeO2 nanowires are promising materials for fabricating FE cathodes.
