An internal friction peak has been observed in bamboo crystals of 99.9999wt%(6N)Al.The height of the peak was found to be proportional to the number of bamboo boundaries contained in the specimen.Analysis of the relax...An internal friction peak has been observed in bamboo crystals of 99.9999wt%(6N)Al.The height of the peak was found to be proportional to the number of bamboo boundaries contained in the specimen.Analysis of the relaxation parameters of this peak shows that this is a new peak associated with the presence of bamboo boundaries.展开更多
Colloidal Au and poly（vinylpyrrolidone） （PVP） composite thin films are fabricated by spin-coating method. Linear optical absorption measurements of the Au/PVP composite films indicate an absorption peak around 530...Colloidal Au and poly（vinylpyrrolidone） （PVP） composite thin films are fabricated by spin-coating method. Linear optical absorption measurements of the Au/PVP composite films indicate an absorption peak around 530 nm due to the surface plasmon resonance of gold nanoparticles. Nonlinear optical properties are studied using standard Z-scan technique, and experimental results show large optical nonlinearities of the Au/PVP composite films. A large value of χ^（3）/α up to 0.56× 10-^10esu·cm is obtained, which is comparable to the best values reported in metal/oxlde composite films.展开更多
Multiwalled carbon nanotubes and BaTiO3 composite films have been prepared by pulsed-laser deposition technique at room temperature and high temperature of 600℃, separately. The structures of the composite films are ...Multiwalled carbon nanotubes and BaTiO3 composite films have been prepared by pulsed-laser deposition technique at room temperature and high temperature of 600℃, separately. The structures of the composite films are investigated by using scanning electron microscopy and x-ray diffraction. The optical behaviours of the samples produced at different temperatures are compared with Raman spectroscopy, and UV-visible absorption. And the observation by Z-scan technique reveals that the composite films have a larger optical nonlinearity, and the samples prepared at high temperatures have better transmittance and opposite sign imaginary part of optical third-order nonlinearity.展开更多
CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated....CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated. Epitaxial films of YBCO were then grown in situ on the CeO2/YSZ （yttria-stabilized ZrO2）/CeO2-buffered Ni substrates. The resulting YBCO conductors exhibited self-fleld critical current density Jc of more than 1 MA/cm^2 at 77K and superconducting transition temperature Tc of about 91K.展开更多
Fast photoelectric effects have been observed in MgB2 thin film fabricated by chemical vapour deposition. The rise time was -10 ns and the full width at half-maximum was -185ns for the photovoltaic pulse when the film...Fast photoelectric effects have been observed in MgB2 thin film fabricated by chemical vapour deposition. The rise time was -10 ns and the full width at half-maximum was -185ns for the photovoltaic pulse when the film was irradiated by a 308 nm laser pulse of 25 ns in duration. X-ray diffraction and the scanning electron microscope revealed that the film was polycrystalline with preferred c-axis orientation. We propose that nonequilibrium electron-hole pairs are excited in the grains and grain boundary regions for MgB2 film under ultraviolet laser and then the built-ln electric field near the grain boundaries separates carriers, which lead to the appearance of an instant photovoltage.展开更多
文摘An internal friction peak has been observed in bamboo crystals of 99.9999wt%(6N)Al.The height of the peak was found to be proportional to the number of bamboo boundaries contained in the specimen.Analysis of the relaxation parameters of this peak shows that this is a new peak associated with the presence of bamboo boundaries.
文摘Colloidal Au and poly（vinylpyrrolidone） （PVP） composite thin films are fabricated by spin-coating method. Linear optical absorption measurements of the Au/PVP composite films indicate an absorption peak around 530 nm due to the surface plasmon resonance of gold nanoparticles. Nonlinear optical properties are studied using standard Z-scan technique, and experimental results show large optical nonlinearities of the Au/PVP composite films. A large value of χ^（3）/α up to 0.56× 10-^10esu·cm is obtained, which is comparable to the best values reported in metal/oxlde composite films.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 90406024 and 10574157）.
文摘Multiwalled carbon nanotubes and BaTiO3 composite films have been prepared by pulsed-laser deposition technique at room temperature and high temperature of 600℃, separately. The structures of the composite films are investigated by using scanning electron microscopy and x-ray diffraction. The optical behaviours of the samples produced at different temperatures are compared with Raman spectroscopy, and UV-visible absorption. And the observation by Z-scan technique reveals that the composite films have a larger optical nonlinearity, and the samples prepared at high temperatures have better transmittance and opposite sign imaginary part of optical third-order nonlinearity.
文摘CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated. Epitaxial films of YBCO were then grown in situ on the CeO2/YSZ （yttria-stabilized ZrO2）/CeO2-buffered Ni substrates. The resulting YBCO conductors exhibited self-fleld critical current density Jc of more than 1 MA/cm^2 at 77K and superconducting transition temperature Tc of about 91K.
文摘Fast photoelectric effects have been observed in MgB2 thin film fabricated by chemical vapour deposition. The rise time was -10 ns and the full width at half-maximum was -185ns for the photovoltaic pulse when the film was irradiated by a 308 nm laser pulse of 25 ns in duration. X-ray diffraction and the scanning electron microscope revealed that the film was polycrystalline with preferred c-axis orientation. We propose that nonequilibrium electron-hole pairs are excited in the grains and grain boundary regions for MgB2 film under ultraviolet laser and then the built-ln electric field near the grain boundaries separates carriers, which lead to the appearance of an instant photovoltage.
