The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formatio...The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formation was determined by analyzing the experimental data——either based on the shading ratio data of laser detector or based on the pressure drop data of the flow system. The induction period of CC12F2 (R12) in pure water and that of CH4 in (tetrahydrofuran ＋ water) systems were then measured with the above two methods. Experimental data show that the induction period depends on the driving force exponentially. Flow rate also has a significant influence on the hydrate nucleation. A new induction period model taking the driving force and liquid flow rate into account was proposed. And it is successfully applied to the calculation of the induction period, which is in good agreement with the experimental data obtained in this study.展开更多
Crystals of the low temperature phase b-Ba3Y(BO3)3 have been synthesized by the flux method. The structure of the title compound crystallizes in the hexagonal system, space group P63cm with the following parameters: a...Crystals of the low temperature phase b-Ba3Y(BO3)3 have been synthesized by the flux method. The structure of the title compound crystallizes in the hexagonal system, space group P63cm with the following parameters: a = 9.416(3), c = 17.536(8) ? V = 1346.6(8) ?, Ba3YB3O9, Mr = 677.36, Z = 6, Dc = 5.012 g/cm3, l(MoKa) = 0.71073 ? m = 19.409 mm-1, Flack parameter = 0.02(3), F(000) = 1764, R = 0.0714 and wR = 0.1696 for 1076 observed reflections with I > 2s(I). The compound contains two sets of YO6 octahedra, four sets of BaO9 polyhedra and three sets of BO3 planar triangles.展开更多
The biocompatibility of orthopedic implants is closely related to their elastic modulus and surface properties.The objective of this study was to determine the effects of cold rolling,recrystallization and laser surfa...The biocompatibility of orthopedic implants is closely related to their elastic modulus and surface properties.The objective of this study was to determine the effects of cold rolling,recrystallization and laser surface melting(LSM)on the microstructure and mechanical properties of a biphase(α″+β)Ti-30Nb-4Sn alloy.X-ray diffraction(XRD)texture analysis of the cold-rolled substrate revealed the[302]α″//ND texture component,while analysis of the recrystallized substrate showed the[302]α″//ND and[110]α″//ND components.Theβ-phase texture could not be directly measured by XRD,but the presence of the[111]β//ND texture component was successfully predicted by considering the orientation relationship between theα″andβphases.Nanoindentation measurements showed that the elastic modulus of the cold-rolled substrate(63GPa)was lower than that of the recrystallized substrate(74GPa).Based on the available literature and the results presented here,it is suggested that this difference is caused by the introduction of crystal defects during cold deformation.The combined nanoindentation/EBSD analysis showed that the nanoindentation results are not affected by crystal orientation.LSM of the deformed alloy produced changes in hardness,elastic modulus and crystallographic texture similar to those produced by recrystallization heat treatment,creating a stiffness gradient between surface and substrate.展开更多
A novel approach of two-step laser crystallization for the growth of poly-Si thin film on glass substrate is investigated. Using this approach, we fabricated poly-Si thin film transistors with electron mobility of 103...A novel approach of two-step laser crystallization for the growth of poly-Si thin film on glass substrate is investigated. Using this approach, we fabricated poly-Si thin film transistors with electron mobility of 103 cm2/V·s and on/off current ratio of 1×10~7.They are better than those of the poly-Si TFTs fabricated by conventional single-step excimer laser crystallization. We also analyzed the structure of the laser crystallized poly-Si thin film by spectroscopic ellipsometry, and proposed the models to simulate the poly-Si thin film and calculated the ellipsometric spectra. The calculated results are in good agreement with the measured results.展开更多
A design of diode-pumped Nd.YAG laser with a single crystal that generates simultaneous laser action at the wavelengths of 1064 nm and 1319 nm was presented and continuous-wave （CW） of 588.9 nm was obtained for the ...A design of diode-pumped Nd.YAG laser with a single crystal that generates simultaneous laser action at the wavelengths of 1064 nm and 1319 nm was presented and continuous-wave （CW） of 588.9 nm was obtained for the first time by use of type-I critical phase-matching LBO crystal intracavity sumfrequency mixing. The maximum output power of 62 mW is achieved with an incident pump power of 1.8 W. The optical-to-optical conversion efficiency is up to 3.4% ,and the power instability in 24 h is better than ± 2.7 %.展开更多
Nd3+:GdAl3(BO3)4 (NGAB) crystal with the size of 30 mm was grown from the solvent system of K2O-Gd2O3-MoO3-B2O3 by combining accelerated seed rotation technology with medium seeded solution growth (MSSG) method, and i...Nd3+:GdAl3(BO3)4 (NGAB) crystal with the size of 30 mm was grown from the solvent system of K2O-Gd2O3-MoO3-B2O3 by combining accelerated seed rotation technology with medium seeded solution growth (MSSG) method, and its crystal structure has been determined by X-ray powder diffraction. It crystallizes in the trigonal system, space group R32 with a = 9.2734(2), c = 7.2438(1) ? V = 538 ?, Z = 3 and Dc = 4.379 g/cm3. The absorption and emission spectra of NGAB in the function of s and polarizations at room temperature have been measured. UV generation tuneable in 378～382 nm, green (531 nm) generation and blue generation tuneable in 436～443 nm as well as red (669 nm) generation by self-frequency changing were obtained with the output of 105, 119.5, 445 and 19 mJ/pulse, respectively, when the crystal was pumped by a dye laser.展开更多
It is considered the mechanism of streamer discharge in the wide-gap semiconductors as a highly effective method of the laser excitation on the basis of representation about the phenomenon of light self-trapping of th...It is considered the mechanism of streamer discharge in the wide-gap semiconductors as a highly effective method of the laser excitation on the basis of representation about the phenomenon of light self-trapping of the discharge, providing their high propagation velocity down to v- 5 ×10^9 sm/s, the crystallographic orientation, filamentary character at thickness of the channel about 1 μm and absence of destructions of a crystal.展开更多
基金the National 973 Program of China (No. 2001CB209107) the National 863 Project of China (No. 2002AA615120) Huo Yingdong Education Foundation.
文摘The appearance of turbidity due to large numbers of critical size hydrate nuclei may significantly affect the outgoing light intensity and the flow resistance in the pipe loop. The induction period of hydrate formation was determined by analyzing the experimental data——either based on the shading ratio data of laser detector or based on the pressure drop data of the flow system. The induction period of CC12F2 (R12) in pure water and that of CH4 in (tetrahydrofuran ＋ water) systems were then measured with the above two methods. Experimental data show that the induction period depends on the driving force exponentially. Flow rate also has a significant influence on the hydrate nucleation. A new induction period model taking the driving force and liquid flow rate into account was proposed. And it is successfully applied to the calculation of the induction period, which is in good agreement with the experimental data obtained in this study.
基金The project was supported by the Key Project of Science and Technology of Fujian province (2001H107) and the National Natural Science Foundation of China (N0. 50272066)
文摘Crystals of the low temperature phase b-Ba3Y(BO3)3 have been synthesized by the flux method. The structure of the title compound crystallizes in the hexagonal system, space group P63cm with the following parameters: a = 9.416(3), c = 17.536(8) ? V = 1346.6(8) ?, Ba3YB3O9, Mr = 677.36, Z = 6, Dc = 5.012 g/cm3, l(MoKa) = 0.71073 ? m = 19.409 mm-1, Flack parameter = 0.02(3), F(000) = 1764, R = 0.0714 and wR = 0.1696 for 1076 observed reflections with I > 2s(I). The compound contains two sets of YO6 octahedra, four sets of BaO9 polyhedra and three sets of BO3 planar triangles.
基金supported by the Brazilian Funding Agencies CAPES(Federal Agency for the Support and Improvement of Higher Education)(Grant No.33003017)CNPq(National Council for Scientific and Technological Development)(Grant No.233006/2014-1)FAPESP(Sao Paulo Research Foundation)(Grant No.2011/19982-2)
文摘The biocompatibility of orthopedic implants is closely related to their elastic modulus and surface properties.The objective of this study was to determine the effects of cold rolling,recrystallization and laser surface melting(LSM)on the microstructure and mechanical properties of a biphase(α″+β)Ti-30Nb-4Sn alloy.X-ray diffraction(XRD)texture analysis of the cold-rolled substrate revealed the[302]α″//ND texture component,while analysis of the recrystallized substrate showed the[302]α″//ND and[110]α″//ND components.Theβ-phase texture could not be directly measured by XRD,but the presence of the[111]β//ND texture component was successfully predicted by considering the orientation relationship between theα″andβphases.Nanoindentation measurements showed that the elastic modulus of the cold-rolled substrate(63GPa)was lower than that of the recrystallized substrate(74GPa).Based on the available literature and the results presented here,it is suggested that this difference is caused by the introduction of crystal defects during cold deformation.The combined nanoindentation/EBSD analysis showed that the nanoindentation results are not affected by crystal orientation.LSM of the deformed alloy produced changes in hardness,elastic modulus and crystallographic texture similar to those produced by recrystallization heat treatment,creating a stiffness gradient between surface and substrate.
文摘A novel approach of two-step laser crystallization for the growth of poly-Si thin film on glass substrate is investigated. Using this approach, we fabricated poly-Si thin film transistors with electron mobility of 103 cm2/V·s and on/off current ratio of 1×10~7.They are better than those of the poly-Si TFTs fabricated by conventional single-step excimer laser crystallization. We also analyzed the structure of the laser crystallized poly-Si thin film by spectroscopic ellipsometry, and proposed the models to simulate the poly-Si thin film and calculated the ellipsometric spectra. The calculated results are in good agreement with the measured results.
文摘A design of diode-pumped Nd.YAG laser with a single crystal that generates simultaneous laser action at the wavelengths of 1064 nm and 1319 nm was presented and continuous-wave （CW） of 588.9 nm was obtained for the first time by use of type-I critical phase-matching LBO crystal intracavity sumfrequency mixing. The maximum output power of 62 mW is achieved with an incident pump power of 1.8 W. The optical-to-optical conversion efficiency is up to 3.4% ,and the power instability in 24 h is better than ± 2.7 %.
基金Supported by the Natural Science Foundation of Fujian province (2000F007)
文摘Nd3+:GdAl3(BO3)4 (NGAB) crystal with the size of 30 mm was grown from the solvent system of K2O-Gd2O3-MoO3-B2O3 by combining accelerated seed rotation technology with medium seeded solution growth (MSSG) method, and its crystal structure has been determined by X-ray powder diffraction. It crystallizes in the trigonal system, space group R32 with a = 9.2734(2), c = 7.2438(1) ? V = 538 ?, Z = 3 and Dc = 4.379 g/cm3. The absorption and emission spectra of NGAB in the function of s and polarizations at room temperature have been measured. UV generation tuneable in 378～382 nm, green (531 nm) generation and blue generation tuneable in 436～443 nm as well as red (669 nm) generation by self-frequency changing were obtained with the output of 105, 119.5, 445 and 19 mJ/pulse, respectively, when the crystal was pumped by a dye laser.
文摘It is considered the mechanism of streamer discharge in the wide-gap semiconductors as a highly effective method of the laser excitation on the basis of representation about the phenomenon of light self-trapping of the discharge, providing their high propagation velocity down to v- 5 ×10^9 sm/s, the crystallographic orientation, filamentary character at thickness of the channel about 1 μm and absence of destructions of a crystal.
