The altitudinal pattern of vegetation is usually identified by field surveys,however,these can only provide discrete data on a local mountain.Few studies identifying and analyzing the altitudinal vegetation pattern on...The altitudinal pattern of vegetation is usually identified by field surveys,however,these can only provide discrete data on a local mountain.Few studies identifying and analyzing the altitudinal vegetation pattern on a regional scale are available.This study selected central Inner Mongolia as the study area,presented a method for extracting vegetation patterns in altitudinal and horizontal directions.The data included a vegetation map at a 1∶1 000 000 scale and a digital elevation model at a 1∶250 000 scale.The three-dimensional vegetation pattern indicated the distribution probability for each vegetation type and the transition zones between different vegetation landscapes.From low to high elevations,there were five vegetation types in the southern mountain flanks,including the montane steppe,broad-leaved forest,coniferous mixed forest,montane dwarf-scrub and sub-alpine shrub-meadow.Correspondingly,only four vegetation types were found in the northern flanks,except for the montane steppe.This study could provide a general model for understanding the complexity and diversity of mountain environment and landscape.展开更多
The solution of vibration transfer from the subsoil to the structure is demonstrated using the example of a multi-storey reinforced concrete building, founded on a dual foundation plate. An anti-vibration layer of rub...The solution of vibration transfer from the subsoil to the structure is demonstrated using the example of a multi-storey reinforced concrete building, founded on a dual foundation plate. An anti-vibration layer of rubber has been designed between the two plates. Two 3D numerical models of the building take into account the individual storeys, firstly together with the lay-out of the rubber distribution in the foundation pan and secondly without this rubber part. For response analysis, the measured time histories in the construction area were selected and then the typical response was used as an input for a dynamic analysis of the structure.展开更多
This paper mainly uses the method of numerical simulation, and study thermal insulation and energy saving characteristics on the exterior walls of the building and analyze the optimal layout scheme of building exterio...This paper mainly uses the method of numerical simulation, and study thermal insulation and energy saving characteristics on the exterior walls of the building and analyze the optimal layout scheme of building exterior wall and thermal insulation system. Finally, the paper study optimal thickness of insulation materials. The paper elaborate scheme of the existing building energy-saving for exterior wall and the scope of application, the system structure and the construction technology. The results showed that： extruded benzene board that can be used for exterior insulation, frame structure filled with wall preferred ceramsite hollow block. The paper can provides reference selection of insulation for building external wall energy-saving transformation scheme.展开更多
A three-dimensional （3D） numerical model is established and validated for cooling performance optimization between a high-level water collecting natural draft wet cooling tower （HNDWCT） and a usual natural draft w...A three-dimensional （3D） numerical model is established and validated for cooling performance optimization between a high-level water collecting natural draft wet cooling tower （HNDWCT） and a usual natural draft wet cooling tower （UNDWCT） under the actual operation condition at Wanzhou power plant, Chongqing, China. User defined functions （UDFs） of source terms are composed and loaded into the spray, fill and rain zones. Consider- ing the conditions of impact on three kinds of corrugated fills （Double-oblique wave, Two-way wave and S wave） and four kinds of fill height （1.25 m, 1.5 m, 1.75 m and 2 In）, numerical simulation of cooling performance are analysed. The results demonstrate that the S wave has the highest cooling efficiency in three fills for both towers, indicating that fill characteristics arc crucial to cooling performance. Moreover, the cooling performance of the HNDWCT is far superior to that of the UNDWCT with fill height increases of 1.75 m and above, because the air mass flow rate in the fill zone of the HNDWCT improves more than that in the UNDWCT, as a result of the rain zone resistance declining sharply for the HNDWCT. In addition, the mass and heat transfer capacity of the HNDWCT is better in the tower centre zone than in the outer zone near the tower wall under a uniform fill layout. This behaviour is inverted for the UNDWCT, perhaps because the high-level collection devices play the role of flow guiding in the inner zone. Therefore, when non-uniform fill layout optimization is applied to the HNDWCT, the inner zone increases in height from 1.75 m to 2 m, the outer zone reduces in height from 1.75 m to 1.5 m, and the outlet water temperature declines approximately 0.4 K compared to that of the uniform layout.展开更多
In this paper, compared with two-transistor (2T) inverter chain, the production and propagation of P-hit single event transient (SET) in three-transistor (3T) inverter chain is studied in depth based on three-dimensio...In this paper, compared with two-transistor (2T) inverter chain, the production and propagation of P-hit single event transient (SET) in three-transistor (3T) inverter chain is studied in depth based on three-dimensional numerical simulations in a 90 nm bulk complementary metal oxide semiconductor (CMOS) technology. The pulse attenuation effect is found in 3T inverter chain, and the pulse can not completely propagate through the inverter chain as LET increases. The discovery will provide a new insight into SET hardened design, the 3T inverter layout structure (or similar layout structures) will be a better method in integrated circuits (ICs) design in radiation environment.展开更多
In this paper, the global properties of a mathematical modeling of hepatitis C virus （HCV） with distributed time delays is studied. Lyapunov functionals are constructed to establish the global asymptotic stability o...In this paper, the global properties of a mathematical modeling of hepatitis C virus （HCV） with distributed time delays is studied. Lyapunov functionals are constructed to establish the global asymptotic stability of the uninfected and infected steady states. It is shown that if the basic reproduction number R0 is less than unity, then the uninfected steady state is globally asymptotically stable. If the basic reproduction number R0 is larger than unity, then the infected steady state is globally asymptotically stable.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41001111,41030528)
文摘The altitudinal pattern of vegetation is usually identified by field surveys,however,these can only provide discrete data on a local mountain.Few studies identifying and analyzing the altitudinal vegetation pattern on a regional scale are available.This study selected central Inner Mongolia as the study area,presented a method for extracting vegetation patterns in altitudinal and horizontal directions.The data included a vegetation map at a 1∶1 000 000 scale and a digital elevation model at a 1∶250 000 scale.The three-dimensional vegetation pattern indicated the distribution probability for each vegetation type and the transition zones between different vegetation landscapes.From low to high elevations,there were five vegetation types in the southern mountain flanks,including the montane steppe,broad-leaved forest,coniferous mixed forest,montane dwarf-scrub and sub-alpine shrub-meadow.Correspondingly,only four vegetation types were found in the northern flanks,except for the montane steppe.This study could provide a general model for understanding the complexity and diversity of mountain environment and landscape.
文摘The solution of vibration transfer from the subsoil to the structure is demonstrated using the example of a multi-storey reinforced concrete building, founded on a dual foundation plate. An anti-vibration layer of rubber has been designed between the two plates. Two 3D numerical models of the building take into account the individual storeys, firstly together with the lay-out of the rubber distribution in the foundation pan and secondly without this rubber part. For response analysis, the measured time histories in the construction area were selected and then the typical response was used as an input for a dynamic analysis of the structure.
文摘This paper mainly uses the method of numerical simulation, and study thermal insulation and energy saving characteristics on the exterior walls of the building and analyze the optimal layout scheme of building exterior wall and thermal insulation system. Finally, the paper study optimal thickness of insulation materials. The paper elaborate scheme of the existing building energy-saving for exterior wall and the scope of application, the system structure and the construction technology. The results showed that： extruded benzene board that can be used for exterior insulation, frame structure filled with wall preferred ceramsite hollow block. The paper can provides reference selection of insulation for building external wall energy-saving transformation scheme.
基金financially supported by the National Major Projects of China(Grant No.2014ZX07406002-2)
文摘A three-dimensional （3D） numerical model is established and validated for cooling performance optimization between a high-level water collecting natural draft wet cooling tower （HNDWCT） and a usual natural draft wet cooling tower （UNDWCT） under the actual operation condition at Wanzhou power plant, Chongqing, China. User defined functions （UDFs） of source terms are composed and loaded into the spray, fill and rain zones. Consider- ing the conditions of impact on three kinds of corrugated fills （Double-oblique wave, Two-way wave and S wave） and four kinds of fill height （1.25 m, 1.5 m, 1.75 m and 2 In）, numerical simulation of cooling performance are analysed. The results demonstrate that the S wave has the highest cooling efficiency in three fills for both towers, indicating that fill characteristics arc crucial to cooling performance. Moreover, the cooling performance of the HNDWCT is far superior to that of the UNDWCT with fill height increases of 1.75 m and above, because the air mass flow rate in the fill zone of the HNDWCT improves more than that in the UNDWCT, as a result of the rain zone resistance declining sharply for the HNDWCT. In addition, the mass and heat transfer capacity of the HNDWCT is better in the tower centre zone than in the outer zone near the tower wall under a uniform fill layout. This behaviour is inverted for the UNDWCT, perhaps because the high-level collection devices play the role of flow guiding in the inner zone. Therefore, when non-uniform fill layout optimization is applied to the HNDWCT, the inner zone increases in height from 1.75 m to 2 m, the outer zone reduces in height from 1.75 m to 1.5 m, and the outlet water temperature declines approximately 0.4 K compared to that of the uniform layout.
基金supported by the Key Program of the National Natural Science Foundation of China (Grant No.60836004)the National Natural Science Foundation of China (Grant Nos.61006070,61076025)
文摘In this paper, compared with two-transistor (2T) inverter chain, the production and propagation of P-hit single event transient (SET) in three-transistor (3T) inverter chain is studied in depth based on three-dimensional numerical simulations in a 90 nm bulk complementary metal oxide semiconductor (CMOS) technology. The pulse attenuation effect is found in 3T inverter chain, and the pulse can not completely propagate through the inverter chain as LET increases. The discovery will provide a new insight into SET hardened design, the 3T inverter layout structure (or similar layout structures) will be a better method in integrated circuits (ICs) design in radiation environment.
文摘In this paper, the global properties of a mathematical modeling of hepatitis C virus （HCV） with distributed time delays is studied. Lyapunov functionals are constructed to establish the global asymptotic stability of the uninfected and infected steady states. It is shown that if the basic reproduction number R0 is less than unity, then the uninfected steady state is globally asymptotically stable. If the basic reproduction number R0 is larger than unity, then the infected steady state is globally asymptotically stable.
