The characteristics of broken surfaces were r esearched by a scanning electron microscope (SEM) and a reflection microscope, a nd the fractal dimensions of broken surfaces were measured by the Slit Island me thod. Th...The characteristics of broken surfaces were r esearched by a scanning electron microscope (SEM) and a reflection microscope, a nd the fractal dimensions of broken surfaces were measured by the Slit Island me thod. The experimental results indicate that the broken surface of aluminum elec tric porcelain is a fractal body in statistics, and the fractal dimensions of br oken surfaces are different with the different amplification multiple value.In a ll of measured fractal dimensions,both of values measured in 100× under reflect ion microscope and in 500× under SEM are maximum, whereas the values measur ed in 63× under reflection microscope and in 2000× under SEM are obviously min imum. The fractal dimensions of broken surfaces are also affected by the degrees of gray comparison and the kinds of measuring methods. The relationships betwee n the fractal dimensions of broken surfaces and porcelain bend strengths are tha t they are in positive correlation on the low multiples and in negative correlat ion on the high multiples.展开更多
Utilized degradable data of coal-filled films from the accelerated UV chamber ageing degradation experiments, and on the basis of control factors’ analysis, presented a predicting model on degradable properties of th...Utilized degradable data of coal-filled films from the accelerated UV chamber ageing degradation experiments, and on the basis of control factors’ analysis, presented a predicting model on degradable properties of this film in photo-degradation according to back-propagation artificial neural network (BP ANN). 4 controlling factors in films degrada-tion, including temperature, the time of UV irradiation, the concentration and the type of coals were used as input parameters in the ANN model. While the degradable properties after film degradation, including the mechanical properties and carbonyl index, were used as output parameters. It was carried out by the neural network toolbox of Matlab 6.5 soft-ware and Visual Basic 6.0. Discussed partition of sample data and model’s parameters, and then selected the best configuration of ANN network. The accurate scope of predicting results was analyzed. This model has a high precision in predicting on properties of the coal-filled film degradation.展开更多
In this paper, several dicalcium silicates (β-C2S) obtained from impurities have been studied. A study of the structure and properties of these doped dicalcium silicates reveals that the doping with MgO of BaSO4 enha...In this paper, several dicalcium silicates (β-C2S) obtained from impurities have been studied. A study of the structure and properties of these doped dicalcium silicates reveals that the doping with MgO of BaSO4 enhanced their activity and rate of hydration, K2O has a similar effect rough less pronounced.The lattice distortion and crystal size in β-dicalcium silicates are measured by X-ray powder diffraction technique, the binding energies of 2P3 for Ca and 2P for Si are obtained by X-ray photoelectric spectrum, the vibrations of the chemical bonds in silicate anion 〔SiO4〕4- are examined by FT-IR and Laser Raman spectra and the heat evolution during hydration reaction for β-dicalcium silicates are determined by microcalorimetry. From the results of XRD, XPS, FT-IR, Raman and micro- DSC, the relationship between the microstructure and properties of doped dicalcium silicates and the mechanism of activation due to impurities are discussed. It is pointed out that the essential factors causing the enhancement of activity and acceleration of hydration reaction are the lattice distortion, crystal size,intercrystalline imperfections, the crystallochemical environment change and chemical shifts of the electron binding energies of Ca and Si atoms in doped β-dicalcium silicates.展开更多
Composite perovskite piezoelectric ceramics of PMMN quaternary system were prepared by cold-pressing and solid-phase sintering.Piezoelectric modulus and density of the samples were measured after polarization.X-ray di...Composite perovskite piezoelectric ceramics of PMMN quaternary system were prepared by cold-pressing and solid-phase sintering.Piezoelectric modulus and density of the samples were measured after polarization.X-ray diffraction analysis and SEM were used to prove the result that the major phase of the piezoelectric ceramic spectimen based on PZT is PZT phase,which is tetragonal system and P-4mm space group.展开更多
With positron annihilation radiation one dimension angular-correlation device, it is measured that positron annihilation radiation one dimension angular-correlation curves of polycrystal sodium ion conductor Na5Y1-x C...With positron annihilation radiation one dimension angular-correlation device, it is measured that positron annihilation radiation one dimension angular-correlation curves of polycrystal sodium ion conductor Na5Y1-x CrxSi4O12 (NYCS) system. After electron momentum distribution curves are normalized, linear parameters are calculated. The parameters H, W and S show the change of Na+ ion vacancy concentration in NYCS series samples. The results show that parameters H, W and S of one dimension angular-correlation curves of those samples vary greatly with Cr2O3 contents. With Cr2O3 content increasing, H and S parameters increase, but W decreases, and reaches extremes at x=0.05; then with Cr2O3 adding continually, parameters H and S decrease gradually, parameter W increases gradually. This shows that, in addtion to Cr2O3, the conductivity has close relation with the concentration of Na+ ion vacancy.展开更多
In this paper, the kind of remanent small molecules in unsaturated polyester res(?) (UP resin) , the best extractant and the best suitalbe extractive time for measuring the content of these small molecules were studie...In this paper, the kind of remanent small molecules in unsaturated polyester res(?) (UP resin) , the best extractant and the best suitalbe extractive time for measuring the content of these small molecules were studied using ultraviolet- visible spectrophotometry ( UV-VIS method). According to the principle of additivity lightness absorption for mixid solution, the contents of samll molecules in several kinds of cured UP resin were measured. It is pointed out that the UV-VIS method in the assay quality of food grade GRP products is more suitable to China.展开更多
A kind of hybrid polyimide films was prepared by synthesizing poly(amic acid)/Silica matrix resin through sol-gel technique and then followed by positing it on a silex glass plate and drying at high temperature. The e...A kind of hybrid polyimide films was prepared by synthesizing poly(amic acid)/Silica matrix resin through sol-gel technique and then followed by positing it on a silex glass plate and drying at high temperature. The effect of silica content on the corona-resistant property of the films was studied. The miscibility between the organic and inorganic phases and its effect on the corona-resistant property were investigated with aminopropyltriethoxysilane, which served as a coupling agent, added into the polyimide composite system. The chemical structure and the surface morphology of the films were characterized by FTIR and AFM respectively. The corona-resistant property of the films was tested by a rod-plate electrode. It proved that the corona-resistant property was enhanced with silica content. It also turned out that the improvement of the miscibility between the two phases due to the presence of covalent force as a result of the addition of the coupling agent had, to some extent, effect on the corona-resistant property of the films. Furthermore, a theory on the corona-resistant property was put forward preliminarily.展开更多
基金Funded by the Natural Science Foundation of Shaanxi Province(No.2003E225)
文摘The characteristics of broken surfaces were r esearched by a scanning electron microscope (SEM) and a reflection microscope, a nd the fractal dimensions of broken surfaces were measured by the Slit Island me thod. The experimental results indicate that the broken surface of aluminum elec tric porcelain is a fractal body in statistics, and the fractal dimensions of br oken surfaces are different with the different amplification multiple value.In a ll of measured fractal dimensions,both of values measured in 100× under reflect ion microscope and in 500× under SEM are maximum, whereas the values measur ed in 63× under reflection microscope and in 2000× under SEM are obviously min imum. The fractal dimensions of broken surfaces are also affected by the degrees of gray comparison and the kinds of measuring methods. The relationships betwee n the fractal dimensions of broken surfaces and porcelain bend strengths are tha t they are in positive correlation on the low multiples and in negative correlat ion on the high multiples.
基金Supported by the National Natural Science Fund ( 20276056)Special Fund of Education Department of Shaanxi Province (03JK190)
文摘Utilized degradable data of coal-filled films from the accelerated UV chamber ageing degradation experiments, and on the basis of control factors’ analysis, presented a predicting model on degradable properties of this film in photo-degradation according to back-propagation artificial neural network (BP ANN). 4 controlling factors in films degrada-tion, including temperature, the time of UV irradiation, the concentration and the type of coals were used as input parameters in the ANN model. While the degradable properties after film degradation, including the mechanical properties and carbonyl index, were used as output parameters. It was carried out by the neural network toolbox of Matlab 6.5 soft-ware and Visual Basic 6.0. Discussed partition of sample data and model’s parameters, and then selected the best configuration of ANN network. The accurate scope of predicting results was analyzed. This model has a high precision in predicting on properties of the coal-filled film degradation.
文摘In this paper, several dicalcium silicates (β-C2S) obtained from impurities have been studied. A study of the structure and properties of these doped dicalcium silicates reveals that the doping with MgO of BaSO4 enhanced their activity and rate of hydration, K2O has a similar effect rough less pronounced.The lattice distortion and crystal size in β-dicalcium silicates are measured by X-ray powder diffraction technique, the binding energies of 2P3 for Ca and 2P for Si are obtained by X-ray photoelectric spectrum, the vibrations of the chemical bonds in silicate anion 〔SiO4〕4- are examined by FT-IR and Laser Raman spectra and the heat evolution during hydration reaction for β-dicalcium silicates are determined by microcalorimetry. From the results of XRD, XPS, FT-IR, Raman and micro- DSC, the relationship between the microstructure and properties of doped dicalcium silicates and the mechanism of activation due to impurities are discussed. It is pointed out that the essential factors causing the enhancement of activity and acceleration of hydration reaction are the lattice distortion, crystal size,intercrystalline imperfections, the crystallochemical environment change and chemical shifts of the electron binding energies of Ca and Si atoms in doped β-dicalcium silicates.
文摘Composite perovskite piezoelectric ceramics of PMMN quaternary system were prepared by cold-pressing and solid-phase sintering.Piezoelectric modulus and density of the samples were measured after polarization.X-ray diffraction analysis and SEM were used to prove the result that the major phase of the piezoelectric ceramic spectimen based on PZT is PZT phase,which is tetragonal system and P-4mm space group.
文摘With positron annihilation radiation one dimension angular-correlation device, it is measured that positron annihilation radiation one dimension angular-correlation curves of polycrystal sodium ion conductor Na5Y1-x CrxSi4O12 (NYCS) system. After electron momentum distribution curves are normalized, linear parameters are calculated. The parameters H, W and S show the change of Na+ ion vacancy concentration in NYCS series samples. The results show that parameters H, W and S of one dimension angular-correlation curves of those samples vary greatly with Cr2O3 contents. With Cr2O3 content increasing, H and S parameters increase, but W decreases, and reaches extremes at x=0.05; then with Cr2O3 adding continually, parameters H and S decrease gradually, parameter W increases gradually. This shows that, in addtion to Cr2O3, the conductivity has close relation with the concentration of Na+ ion vacancy.
文摘In this paper, the kind of remanent small molecules in unsaturated polyester res(?) (UP resin) , the best extractant and the best suitalbe extractive time for measuring the content of these small molecules were studied using ultraviolet- visible spectrophotometry ( UV-VIS method). According to the principle of additivity lightness absorption for mixid solution, the contents of samll molecules in several kinds of cured UP resin were measured. It is pointed out that the UV-VIS method in the assay quality of food grade GRP products is more suitable to China.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50137010, 50373008 and 50377009).
文摘A kind of hybrid polyimide films was prepared by synthesizing poly(amic acid)/Silica matrix resin through sol-gel technique and then followed by positing it on a silex glass plate and drying at high temperature. The effect of silica content on the corona-resistant property of the films was studied. The miscibility between the organic and inorganic phases and its effect on the corona-resistant property were investigated with aminopropyltriethoxysilane, which served as a coupling agent, added into the polyimide composite system. The chemical structure and the surface morphology of the films were characterized by FTIR and AFM respectively. The corona-resistant property of the films was tested by a rod-plate electrode. It proved that the corona-resistant property was enhanced with silica content. It also turned out that the improvement of the miscibility between the two phases due to the presence of covalent force as a result of the addition of the coupling agent had, to some extent, effect on the corona-resistant property of the films. Furthermore, a theory on the corona-resistant property was put forward preliminarily.
