The coherent elastic strain-induced morphological transformation of a binarycubic model alloy was simulated with different strain energy parameters. The microscopic diffusionequation was combined with the theory of mi...The coherent elastic strain-induced morphological transformation of a binarycubic model alloy was simulated with different strain energy parameters. The microscopic diffusionequation was combined with the theory of microscopic elasticity. The results show that when thestrain energy is neglected, the randomly distributed equiaxed particles are obtained with isotropiccharacteristic. It is coarsening that follows the Ostwald ripening mechanism: smaller particlesdwindle and larger particles grow; when the elastic strain is considered, plate precipitates tend toalign along the elastically soft directions <01> with anisotropic characteristic. The particlesgrow in the soft directions and coarsen further; particles dwindle in out of the soft directions.While the coarsening of the particles localized in the same row or column follows the rule: smallerparticles shrink and larger ones grow.展开更多
The development of sustainability has made the application of green concepts to cityscapes and urban design mandatory and has popularized the installation of vegetation on external street walls. Introducing greenery o...The development of sustainability has made the application of green concepts to cityscapes and urban design mandatory and has popularized the installation of vegetation on external street walls. Introducing greenery on external building elements is beneficial to the environment, reducing the heat impact experienced in ＂urban heat islands＂ and enhancing an area＇s visual effect. The popularity of such green systems has necessitated the assessment of their acoustic characteristics and their impact on long-distance noise propagation. These effects become important in hot climates, where the topology of the dense urban texture gives building walls larger areas than exposed streets, thereby amplifying the effects of the former＇s acoustic characteristics on noise levels. Considering the resultant sound level at a particular location between buildings as the contribution of several remote sources, a simplified computer model based on energy exchange is developed in this study. Owing to the complexity of the urban landscape, buildings are assumed to be an array of rectangular blocks. The computer model is used to investigate the effects of the installation of street vertical ve^letation on long-distance noise propagation, as well as those of the geometric parameters of the dense Islamic urban texture on the resultant noise levels.展开更多
The dislocation evolution wassimulated by using positiveand negative parallelstraightedgedislocationsrandomly distributing on the primary slip planes astheinitialconditions. Thevein and wallstructuresof dynamicequilib...The dislocation evolution wassimulated by using positiveand negative parallelstraightedgedislocationsrandomly distributing on the primary slip planes astheinitialconditions. Thevein and wallstructuresof dynamicequilibrium have been obtained. Abig dipolestructure wasfound inthesimulation.展开更多
基金National Natural Science Foundation of China (No.50071046).
文摘The coherent elastic strain-induced morphological transformation of a binarycubic model alloy was simulated with different strain energy parameters. The microscopic diffusionequation was combined with the theory of microscopic elasticity. The results show that when thestrain energy is neglected, the randomly distributed equiaxed particles are obtained with isotropiccharacteristic. It is coarsening that follows the Ostwald ripening mechanism: smaller particlesdwindle and larger particles grow; when the elastic strain is considered, plate precipitates tend toalign along the elastically soft directions <01> with anisotropic characteristic. The particlesgrow in the soft directions and coarsen further; particles dwindle in out of the soft directions.While the coarsening of the particles localized in the same row or column follows the rule: smallerparticles shrink and larger ones grow.
文摘The development of sustainability has made the application of green concepts to cityscapes and urban design mandatory and has popularized the installation of vegetation on external street walls. Introducing greenery on external building elements is beneficial to the environment, reducing the heat impact experienced in ＂urban heat islands＂ and enhancing an area＇s visual effect. The popularity of such green systems has necessitated the assessment of their acoustic characteristics and their impact on long-distance noise propagation. These effects become important in hot climates, where the topology of the dense urban texture gives building walls larger areas than exposed streets, thereby amplifying the effects of the former＇s acoustic characteristics on noise levels. Considering the resultant sound level at a particular location between buildings as the contribution of several remote sources, a simplified computer model based on energy exchange is developed in this study. Owing to the complexity of the urban landscape, buildings are assumed to be an array of rectangular blocks. The computer model is used to investigate the effects of the installation of street vertical ve^letation on long-distance noise propagation, as well as those of the geometric parameters of the dense Islamic urban texture on the resultant noise levels.
文摘The dislocation evolution wassimulated by using positiveand negative parallelstraightedgedislocationsrandomly distributing on the primary slip planes astheinitialconditions. Thevein and wallstructuresof dynamicequilibrium have been obtained. Abig dipolestructure wasfound inthesimulation.
