Drought is one of the extreme events that can be caused by internal climate variability （ICV） and external forcing （EF）. Here, the authors investigate the relative contributions of ICY and EF to meteorological dro...Drought is one of the extreme events that can be caused by internal climate variability （ICV） and external forcing （EF）. Here, the authors investigate the relative contributions of ICY and EF to meteorological drought changes in China using 40 members from the Community Earth System Model Large Ensemble （CESE_LE） project for historical simulations （in response to greenhouse gases and other EF） and future simulations under the RCP8.5 scenario. The authors use the Standardized Precipitation Index （SPI） to represent meteorological drought, and then define and analyze four drought parameters （frequency, severity, duration, and maximum duration） over eight regions of China. For historical periods, the ICV plays a dominant role in drought variation, while with global warming under the RCP8.5 scenario the EF becomes the prominent factor for drought characteristics. With the global warming signal, the effect of ICV varies with the drought parameters. This study suggests that the ICV should be taken into account when climate model simulations are used to investigate drought--in particular, for historical periods.展开更多
On the basis of the actual steel deck structure of Taizhou Bridge, this paper carries out hot-spot stress analysis on some key spots by using the finite element model which simulates local structure of orthotropic ste...On the basis of the actual steel deck structure of Taizhou Bridge, this paper carries out hot-spot stress analysis on some key spots by using the finite element model which simulates local structure of orthotropic steel bridge decks. A finite element model is established for local structure of orthotropic steel bridge decks, and in the analysis of linear elasticity of the structure, face load is employed to simulate the loads from vehicle wheels. Analysis results show that main stresses are relatively heavy at the joints between diaphragm plates, top plates and U-shaped ribs and the joints between diaphragm plates and U-shaped ribs. These joints shall be regarded as key points for hot-spot stress analysis. Different mesh densities are adopted in the finite element model and the main stresses at different hot spots are contrasted and linear extrapolation is carried out using extrapolation formulae. Results show that different mesh densities have different influences on the hot-spot stresses at the welded seams of U-shaped ribs. These influences shall be considered in calculation and analysis.展开更多
Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper p...Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper presents optimization methods for plant landscape design that take account of results of comparisons of noise reduction effects, heat island temperature decreases and effects on ventilation. These methods are based on different plant configurations and various luminous environments, such as exterior sunshine and shaded areas after the simulation of exterior luminous, acoustic and thermal environments of a residential area using the analytic software ECOTECT, CADNA/A, and PHEONICS. Three different types of residential buildings are simulated including a faculty apartment in the Xixi Campus of Zhejiang University, the Huaqing Villa and the Gangwan Jiayuan faculty apartment of Zhejiang University, China, based on green building design theory. In addition, the methods and process flow of landscape design of green residential areas are also described for the improvement of the exterior physical living environment.展开更多
基金supported by the Key Project of the Ministry of Science and Technology of China[grant number2016YFA0602401]the National Natural Science Foundation of China[grant number 41275110]supported by the National Science Foundation[grant number AGS-0944101]
文摘Drought is one of the extreme events that can be caused by internal climate variability （ICV） and external forcing （EF）. Here, the authors investigate the relative contributions of ICY and EF to meteorological drought changes in China using 40 members from the Community Earth System Model Large Ensemble （CESE_LE） project for historical simulations （in response to greenhouse gases and other EF） and future simulations under the RCP8.5 scenario. The authors use the Standardized Precipitation Index （SPI） to represent meteorological drought, and then define and analyze four drought parameters （frequency, severity, duration, and maximum duration） over eight regions of China. For historical periods, the ICV plays a dominant role in drought variation, while with global warming under the RCP8.5 scenario the EF becomes the prominent factor for drought characteristics. With the global warming signal, the effect of ICV varies with the drought parameters. This study suggests that the ICV should be taken into account when climate model simulations are used to investigate drought--in particular, for historical periods.
基金National Science and Technology Support Program of China(No.2009BAG15B02)Key Programs for Science and Technology Development of Chinese Transportation Industry(No.2008-353-332-180)+1 种基金"333 High-level Personnel Training Project"Special Funded Projects in Jiangsu ProvinceJiangsu Communications Science Research Program(No.08Y29-16)
文摘On the basis of the actual steel deck structure of Taizhou Bridge, this paper carries out hot-spot stress analysis on some key spots by using the finite element model which simulates local structure of orthotropic steel bridge decks. A finite element model is established for local structure of orthotropic steel bridge decks, and in the analysis of linear elasticity of the structure, face load is employed to simulate the loads from vehicle wheels. Analysis results show that main stresses are relatively heavy at the joints between diaphragm plates, top plates and U-shaped ribs and the joints between diaphragm plates and U-shaped ribs. These joints shall be regarded as key points for hot-spot stress analysis. Different mesh densities are adopted in the finite element model and the main stresses at different hot spots are contrasted and linear extrapolation is carried out using extrapolation formulae. Results show that different mesh densities have different influences on the hot-spot stresses at the welded seams of U-shaped ribs. These influences shall be considered in calculation and analysis.
基金Project (No. R1080363) supported by the Zhejiang Provincial Natural Science Foundation of China
文摘Landscape design for a green community should be favorable for the ambient ecological environment and for enhancement of both the local climate of a residential area and the environmental quality of life. This paper presents optimization methods for plant landscape design that take account of results of comparisons of noise reduction effects, heat island temperature decreases and effects on ventilation. These methods are based on different plant configurations and various luminous environments, such as exterior sunshine and shaded areas after the simulation of exterior luminous, acoustic and thermal environments of a residential area using the analytic software ECOTECT, CADNA/A, and PHEONICS. Three different types of residential buildings are simulated including a faculty apartment in the Xixi Campus of Zhejiang University, the Huaqing Villa and the Gangwan Jiayuan faculty apartment of Zhejiang University, China, based on green building design theory. In addition, the methods and process flow of landscape design of green residential areas are also described for the improvement of the exterior physical living environment.
