The effects of starting texture on he flow curves, and microstructure and texture evolutions of AZ31(Mg-3Al-1Zn-0.3Mn in wt.%) alloy during uniaxial compression at room temperature have been investigated by experiment...The effects of starting texture on he flow curves, and microstructure and texture evolutions of AZ31(Mg-3Al-1Zn-0.3Mn in wt.%) alloy during uniaxial compression at room temperature have been investigated by experiments and simulations. Two kinds of cylindrical compression samples were cut from the AZ31 extruded rod: one was cut with the compression direction parallel to the extruded direction(ED), and the other was cut with the compression axis perpendicular to the ED. The samples were termed as C//ED sample and C⊥ED sample, respectively. The results indicate that the general characteristics of flow curves and texture evolutions in both C⊥ED and C//ED samples during compression can be well explained by the relative activities of deformation mechanisms, which show a strong orientation dependence on the initial textures and the current texture. A significant yield behavior can be induced by {10-12} twinning at the starting deformation, and the lower yield stress in C⊥ED sample can be enhanced by the high activity of basal slip. The work hardening behavior is related to the activities of basal slip, pyramidal <c+a> slip, {10-12} twinning, as well as {10-11} twinning. However, the activity of prismatic slip is insensitive to the starting texture, and mostly negligible in all samples.展开更多
从研究出行者个体出行的行为特性出发,研究其择路行为有重要的意义.在自适应规则的基础上,考虑OD(Origin and Destination,简称OD)量服从一个概率分布(本文中假设服从正态分布)的情况下,研究出行者择路的演化.结果表明,对于固定或随机...从研究出行者个体出行的行为特性出发,研究其择路行为有重要的意义.在自适应规则的基础上,考虑OD(Origin and Destination,简称OD)量服从一个概率分布(本文中假设服从正态分布)的情况下,研究出行者择路的演化.结果表明,对于固定或随机的OD量,路径流量均能收敛.并且,当OD量是随机变量时,如果均值一定,方差越大收敛速度越慢;如果方差一定,增大均值基本不会改变收敛速度,但对收敛前路径流量在演化过程中的波动幅度有较大的影响.此外,还考虑了多种交通方式并存下的择路模型及演化.演化结果表明,小汽车出行的不稳定性和自主性要比公交车出行高.展开更多
To conduct a large-scale hydrologic-response and landform evolution simulation at high resolution,a complex physics-based numerical model,the Integrated Hydrology Model(InHM),was revised utilizing cluster parallel com...To conduct a large-scale hydrologic-response and landform evolution simulation at high resolution,a complex physics-based numerical model,the Integrated Hydrology Model(InHM),was revised utilizing cluster parallel computing.The parallelized InHM(ParInHM) divides the simulated area into multiple catchments based on geomorphologic features,and generates boundary-value problems for each catchment to construct simulation tasks,which are then dispatched to different computers to start the simulation.Landform evolution is considered during simulating and implemention in one framework.The dynamical Longest-Processing-Time(LPT) first scheduling algorithm is applied to job management.In addition,a pause-integratedivide-resume routine method is used to ensure the hydrologic validity during the simulation period.The routine repeats until the entire simulation period is finished.ParInHM has been tested in a computer cluster that uses 16 processors for the calculation,to simulate 100 years' hydrologic-response and soil erosion for the 117-km2 Kaho'olawe Island in the Hawaiian Islands under two different mesh resolutions.The efficiency of ParInHM was evaluated by comparing the performance of the cluster system utilizing different numbers of processors,as well as the performance of non-parallelized system without domain decomposition.The results of this study show that it is feasible to conduct a regional-scale hydrologic-response and sediment transport simulation at high resolution without demanding significant computing resources.展开更多
Zirconia-supported CuO （CuO/ZrO2） composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique. For comparison, CuO/ZrO2 materials were also prepared by solid state reaction and ...Zirconia-supported CuO （CuO/ZrO2） composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique. For comparison, CuO/ZrO2 materials were also prepared by solid state reaction and co-precipitation method. The as-prepared powders were characterized by X-ray diffractometry （XRD）, transmission electron microscopy （TEM）, and thermogravimetric-differential thermal analysis （TG-DTA）. The photocatalytic activity of CuO/ZrO2 catalyst was investigated based on the H2 evolution from oxalic acid solution under simulated sunlight irradiation. The effects of molar ratio of CuO to ZrO2, preparation method, phase change with the calcination temperature and the durability on the photocatalytic activity of the photocatalyst were investigated in detail. It is found that the optimal activity of photocatalytic H2 evolution （2.41 mmol.h i.g-~） can be obtained when CuO/ZrO2 composite photocatalyst is synthesized by sol-gel technique and the mole ratio of CuO to ZrO2 is 40%. The activity of copper oxide supported on monoclinic ZrO2 calcined at higher temperature is much higher than that on tetragonal ZrO2 calcined at lower temperature, and the best calcination temperature is 900 ℃.展开更多
The technology innovation cooperation relationship of enterprises has evolved into the representation of complicated network. MATLAB software is used for computer simulation on network evolution process of technology ...The technology innovation cooperation relationship of enterprises has evolved into the representation of complicated network. MATLAB software is used for computer simulation on network evolution process of technology innovation cooperation, and Ucinet characterization analysis software is used to compute characteristic values of simulation network such as power law index of network, average route length and accumulation coefficients. It is compared with the actual network, and the simulation results are analyzed to verify the rationality of the constructed evolution model.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51301040)
文摘The effects of starting texture on he flow curves, and microstructure and texture evolutions of AZ31(Mg-3Al-1Zn-0.3Mn in wt.%) alloy during uniaxial compression at room temperature have been investigated by experiments and simulations. Two kinds of cylindrical compression samples were cut from the AZ31 extruded rod: one was cut with the compression direction parallel to the extruded direction(ED), and the other was cut with the compression axis perpendicular to the ED. The samples were termed as C//ED sample and C⊥ED sample, respectively. The results indicate that the general characteristics of flow curves and texture evolutions in both C⊥ED and C//ED samples during compression can be well explained by the relative activities of deformation mechanisms, which show a strong orientation dependence on the initial textures and the current texture. A significant yield behavior can be induced by {10-12} twinning at the starting deformation, and the lower yield stress in C⊥ED sample can be enhanced by the high activity of basal slip. The work hardening behavior is related to the activities of basal slip, pyramidal <c+a> slip, {10-12} twinning, as well as {10-11} twinning. However, the activity of prismatic slip is insensitive to the starting texture, and mostly negligible in all samples.
文摘从研究出行者个体出行的行为特性出发,研究其择路行为有重要的意义.在自适应规则的基础上,考虑OD(Origin and Destination,简称OD)量服从一个概率分布(本文中假设服从正态分布)的情况下,研究出行者择路的演化.结果表明,对于固定或随机的OD量,路径流量均能收敛.并且,当OD量是随机变量时,如果均值一定,方差越大收敛速度越慢;如果方差一定,增大均值基本不会改变收敛速度,但对收敛前路径流量在演化过程中的波动幅度有较大的影响.此外,还考虑了多种交通方式并存下的择路模型及演化.演化结果表明,小汽车出行的不稳定性和自主性要比公交车出行高.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2011CB409901-1)Zhejiang Provincial Natural Science Foundation of China (Grant No. R5110012)the E-Project of Microsoft Research Asia
文摘To conduct a large-scale hydrologic-response and landform evolution simulation at high resolution,a complex physics-based numerical model,the Integrated Hydrology Model(InHM),was revised utilizing cluster parallel computing.The parallelized InHM(ParInHM) divides the simulated area into multiple catchments based on geomorphologic features,and generates boundary-value problems for each catchment to construct simulation tasks,which are then dispatched to different computers to start the simulation.Landform evolution is considered during simulating and implemention in one framework.The dynamical Longest-Processing-Time(LPT) first scheduling algorithm is applied to job management.In addition,a pause-integratedivide-resume routine method is used to ensure the hydrologic validity during the simulation period.The routine repeats until the entire simulation period is finished.ParInHM has been tested in a computer cluster that uses 16 processors for the calculation,to simulate 100 years' hydrologic-response and soil erosion for the 117-km2 Kaho'olawe Island in the Hawaiian Islands under two different mesh resolutions.The efficiency of ParInHM was evaluated by comparing the performance of the cluster system utilizing different numbers of processors,as well as the performance of non-parallelized system without domain decomposition.The results of this study show that it is feasible to conduct a regional-scale hydrologic-response and sediment transport simulation at high resolution without demanding significant computing resources.
基金Project(20876039) supported by the National Natural Science Foundation of ChinaProject(09JJ3023) supported by the Natural Science Foundation of Hunan Province,China
文摘Zirconia-supported CuO （CuO/ZrO2） composite photocatalysts were successfully synthesized via citric acid-assisted sol-gel technique. For comparison, CuO/ZrO2 materials were also prepared by solid state reaction and co-precipitation method. The as-prepared powders were characterized by X-ray diffractometry （XRD）, transmission electron microscopy （TEM）, and thermogravimetric-differential thermal analysis （TG-DTA）. The photocatalytic activity of CuO/ZrO2 catalyst was investigated based on the H2 evolution from oxalic acid solution under simulated sunlight irradiation. The effects of molar ratio of CuO to ZrO2, preparation method, phase change with the calcination temperature and the durability on the photocatalytic activity of the photocatalyst were investigated in detail. It is found that the optimal activity of photocatalytic H2 evolution （2.41 mmol.h i.g-~） can be obtained when CuO/ZrO2 composite photocatalyst is synthesized by sol-gel technique and the mole ratio of CuO to ZrO2 is 40%. The activity of copper oxide supported on monoclinic ZrO2 calcined at higher temperature is much higher than that on tetragonal ZrO2 calcined at lower temperature, and the best calcination temperature is 900 ℃.
文摘The technology innovation cooperation relationship of enterprises has evolved into the representation of complicated network. MATLAB software is used for computer simulation on network evolution process of technology innovation cooperation, and Ucinet characterization analysis software is used to compute characteristic values of simulation network such as power law index of network, average route length and accumulation coefficients. It is compared with the actual network, and the simulation results are analyzed to verify the rationality of the constructed evolution model.
