Molecular dynamics(MD) simulation of ethene diffusion in the lattice of HZSM 5 was performed at the temperature ranging from 300 K to 700 K. The calculated diffusion coefficients increase with the temperature from 2.6...Molecular dynamics(MD) simulation of ethene diffusion in the lattice of HZSM 5 was performed at the temperature ranging from 300 K to 700 K. The calculated diffusion coefficients increase with the temperature from 2.60×10 -9 m 2/s at 300 K to 12.78×10 -9 m 2/s at 700 K. The Arrhenius plot gives an activation energy of 6.31 kJ/mol . The anisotropy of the diffusion process was examined.展开更多
in order to achieve increased layer thickness, and wearing resistance, enhanced ion implantation with nitrogen has been carried out at temperatures of 100, 200, 400, and 600℃ with a dose of 4x 1018 ions' cm-2. U...in order to achieve increased layer thickness, and wearing resistance, enhanced ion implantation with nitrogen has been carried out at temperatures of 100, 200, 400, and 600℃ with a dose of 4x 1018 ions' cm-2. Using the Plasma Source ion Implantation (PSII) device, specimens of Ti6Al4V alloy were implanted at elevated temperatures, using the ion flux as the heating source. Auger Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), micro-hardness measurements and pin-on-disk wearing tester were utilized to evaluate the surface property improvements. The thickness of the implanted layer increased by about an order of magnitude when the temperature was elevated from 100 to 600℃. Higher surface hardness and wearing resistance was also obtained in implantation under higher temperature. XRD image showed the presence of titanium nitrides on the implanted surface.展开更多
Polyether and polyether/ester based TPU (thermoplastic polyurethanes) were investigated with wide-angle XRD (X-ray diffraction) and SAXS (small angle X-ray scattering). Furthermore, SAXS measurements were perfor...Polyether and polyether/ester based TPU (thermoplastic polyurethanes) were investigated with wide-angle XRD (X-ray diffraction) and SAXS (small angle X-ray scattering). Furthermore, SAXS measurements were performed in the temperature range of 30 ℃ to 130 ℃. Polyether based polymers exhibit only one broad diffraction signal in a region of 2 θ 15° to 25°. In case of polyurethanes with ether/ester modification, the broad diffraction signal arises with small sharp diffraction signals. SAXS measurements of polymers reveal the size and shape of the crystalline zones of the polymer. Between 30 ℃ and 130 ℃ the size of the crystalline zone changes significantly. The size decreases in most of investigated TPU. In the case of Desmopan 9365D an increase of the particle size was observed.展开更多
Dynamical formation and growth of compressible thermal-hyperelastic Gent-Thomas cavity in a sphere composed of two inmaterials were discussed under the case of a non-uniform temperature field and the surface dead load...Dynamical formation and growth of compressible thermal-hyperelastic Gent-Thomas cavity in a sphere composed of two inmaterials were discussed under the case of a non-uniform temperature field and the surface dead loading. The mathematical model was first presented based on the dynamical theory of finite deformations. An exact differential relation between the void radius and surface load was obtained by using the variable transformation method. By numerical computation, critical loads and cavitation growth curves were obtained for different temperatures. The influence of the temperature and material parameters of the composed sphere on the void formation and growth was considered and compared with those for static analysis. The results show that the cavity occurs stiddenly with a finite radius and its evolvement with time displays a non-linear periodic vibration and that the critical load decreases with the increase of temperature and also the dynamical critical load is lower than the static critical load under the same conditions.展开更多
Based on annual mean maximum and minimum temperatures,diurnal temperature range,precipitation,sunshine,total cloud cover and water barometric pressure data in Benxi County from 1958 to 2010,using statistical analysis,...Based on annual mean maximum and minimum temperatures,diurnal temperature range,precipitation,sunshine,total cloud cover and water barometric pressure data in Benxi County from 1958 to 2010,using statistical analysis,the results show that the annual and seasonal diurnal temperature ranges present significant decreasing tendencies,and the reducing tendency is the most remarkable in winter. Autumn reducing tendency is stronger than that in spring,and it is the weakest in summer. Annual and seasonal average temperatures,average maximum and minimum temperatures all present the remarkable rising trends. Rising trend of the minimum temperature is more significant than that of the maximum temperature. The monthly mean diurnal temperature range also presents reducing tendency,and the most reducing scope appear in January and February. Annual and season diurnal temperature range changes are related to sunshine,mean minimum temperature,mean maximum temperature,precipitation,total cloud cover and water barometric pressure,but various essential factors are different in each season. Annual mean temperature,annual mean minimum temperature,annual mean maximum temperature and annual diurnal temperature range all have sudden changes,but the age is inconsistent.展开更多
The impact of supercritical CO2/H2O technology on the threshold-voltage instability of AlGaN/GaN metal-insulator semiconductor high-electron-mobility transistors(MIS-HEMTs) is investigated. The MIS-HEMTs were placed i...The impact of supercritical CO2/H2O technology on the threshold-voltage instability of AlGaN/GaN metal-insulator semiconductor high-electron-mobility transistors(MIS-HEMTs) is investigated. The MIS-HEMTs were placed in a supercritical fluid system chamber at 150℃ for 3 h. The chamber was injected with CO2 and H2O at pressure of 3000 psi(1 psi ≈ 6.895 kPa). Supercritical H2O fluid has the characteristics of liquid H2O and gaseous H2O at the same time, that is, high penetration and high solubility. In addition, OH-produced by ionization of H2O can fill the nitrogen vacancy near the Si3N4/GaN/AlGaN interface caused by high temperature process. After supercritical CO2/H2O treatment, the threshold voltage shift is reduced from 1 V to 0.3 V. The result shows that the threshold voltage shift of MIS-HEMTs could be suppressed by supercritical CO2/H2O treatment.展开更多
基金Supported by the National Natural Science Foundation of China(No.2 97730 2 1) and the Provisional EducationalFoundation of Jiangsu(Granted:98KJB15 0 0 0 1)
文摘Molecular dynamics(MD) simulation of ethene diffusion in the lattice of HZSM 5 was performed at the temperature ranging from 300 K to 700 K. The calculated diffusion coefficients increase with the temperature from 2.60×10 -9 m 2/s at 300 K to 12.78×10 -9 m 2/s at 700 K. The Arrhenius plot gives an activation energy of 6.31 kJ/mol . The anisotropy of the diffusion process was examined.
基金This item was supported by the Defense Science Foundation with Grant No.98JS50.3.3 HZ5801.
文摘in order to achieve increased layer thickness, and wearing resistance, enhanced ion implantation with nitrogen has been carried out at temperatures of 100, 200, 400, and 600℃ with a dose of 4x 1018 ions' cm-2. Using the Plasma Source ion Implantation (PSII) device, specimens of Ti6Al4V alloy were implanted at elevated temperatures, using the ion flux as the heating source. Auger Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), micro-hardness measurements and pin-on-disk wearing tester were utilized to evaluate the surface property improvements. The thickness of the implanted layer increased by about an order of magnitude when the temperature was elevated from 100 to 600℃. Higher surface hardness and wearing resistance was also obtained in implantation under higher temperature. XRD image showed the presence of titanium nitrides on the implanted surface.
文摘Polyether and polyether/ester based TPU (thermoplastic polyurethanes) were investigated with wide-angle XRD (X-ray diffraction) and SAXS (small angle X-ray scattering). Furthermore, SAXS measurements were performed in the temperature range of 30 ℃ to 130 ℃. Polyether based polymers exhibit only one broad diffraction signal in a region of 2 θ 15° to 25°. In case of polyurethanes with ether/ester modification, the broad diffraction signal arises with small sharp diffraction signals. SAXS measurements of polymers reveal the size and shape of the crystalline zones of the polymer. Between 30 ℃ and 130 ℃ the size of the crystalline zone changes significantly. The size decreases in most of investigated TPU. In the case of Desmopan 9365D an increase of the particle size was observed.
基金Project supported by the National Natural Science Foundation of China (No.10272069)Shanghai Leading Academic Discipline Project (No.Y0103)
文摘Dynamical formation and growth of compressible thermal-hyperelastic Gent-Thomas cavity in a sphere composed of two inmaterials were discussed under the case of a non-uniform temperature field and the surface dead loading. The mathematical model was first presented based on the dynamical theory of finite deformations. An exact differential relation between the void radius and surface load was obtained by using the variable transformation method. By numerical computation, critical loads and cavitation growth curves were obtained for different temperatures. The influence of the temperature and material parameters of the composed sphere on the void formation and growth was considered and compared with those for static analysis. The results show that the cavity occurs stiddenly with a finite radius and its evolvement with time displays a non-linear periodic vibration and that the critical load decreases with the increase of temperature and also the dynamical critical load is lower than the static critical load under the same conditions.
文摘Based on annual mean maximum and minimum temperatures,diurnal temperature range,precipitation,sunshine,total cloud cover and water barometric pressure data in Benxi County from 1958 to 2010,using statistical analysis,the results show that the annual and seasonal diurnal temperature ranges present significant decreasing tendencies,and the reducing tendency is the most remarkable in winter. Autumn reducing tendency is stronger than that in spring,and it is the weakest in summer. Annual and seasonal average temperatures,average maximum and minimum temperatures all present the remarkable rising trends. Rising trend of the minimum temperature is more significant than that of the maximum temperature. The monthly mean diurnal temperature range also presents reducing tendency,and the most reducing scope appear in January and February. Annual and season diurnal temperature range changes are related to sunshine,mean minimum temperature,mean maximum temperature,precipitation,total cloud cover and water barometric pressure,but various essential factors are different in each season. Annual mean temperature,annual mean minimum temperature,annual mean maximum temperature and annual diurnal temperature range all have sudden changes,but the age is inconsistent.
基金Project supported by Shenzhen Science and Technology Innovation Committee(Grant Nos.ZDSYS201802061805105,JCYJ20190808155007550,QJSCX20170728102129176,and JCYJ20170810163407761)the National Natural Science Foundation of China(Grant No.U1613215).
文摘The impact of supercritical CO2/H2O technology on the threshold-voltage instability of AlGaN/GaN metal-insulator semiconductor high-electron-mobility transistors(MIS-HEMTs) is investigated. The MIS-HEMTs were placed in a supercritical fluid system chamber at 150℃ for 3 h. The chamber was injected with CO2 and H2O at pressure of 3000 psi(1 psi ≈ 6.895 kPa). Supercritical H2O fluid has the characteristics of liquid H2O and gaseous H2O at the same time, that is, high penetration and high solubility. In addition, OH-produced by ionization of H2O can fill the nitrogen vacancy near the Si3N4/GaN/AlGaN interface caused by high temperature process. After supercritical CO2/H2O treatment, the threshold voltage shift is reduced from 1 V to 0.3 V. The result shows that the threshold voltage shift of MIS-HEMTs could be suppressed by supercritical CO2/H2O treatment.