The mechanical property of saline soils varies with moisture and climate in the cold and salt lake region of Qinghai-Tibet Plateau, which influences project construction. In order to improve foundation reinforcement e...The mechanical property of saline soils varies with moisture and climate in the cold and salt lake region of Qinghai-Tibet Plateau, which influences project construction. In order to improve foundation reinforcement effect of the QarharvaTrolmud Highway, Qinghai Province, China, dynamic compaction replacement （DCR） composite foundation was applied in saline soils. A field experiment was conducted in this area, where strength and working mechanism of pier-soil and deformation modulus of the composite foundation was analyzed after reinforcement. This paper presents methods for determining the coefficient on the bearing capacity evaluation and deformation modulus of composite foundation with DC1L Reinforcement case of DCR is highly effective in saline soils of the salt lake regions, which helps the mi-tion of water and salt in saline soils.展开更多
Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis woodlands in central Texas. It has high density, but plants are mostly in the community understory. Light response c...Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis woodlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of CO<sub>2</sub> and temperature were measured for D. texana. The A<sub>net</sub> (photosynthetic rate) increased significantly as both light level and CO<sub>2</sub> levels increased but not temperature. The A<sub>max</sub> (maximum photosynthetic rate) of D. texana in full sun at elevated levels of CO<sub>2</sub> was increased for all treatments. Stomatal conductance increased with levels of CO<sub>2</sub> but only if the interaction was removed from the model. Intercellular levels of CO<sub>2</sub> increased with both temperature and CO<sub>2</sub> treatments as did water use efficiency (WUE). Furthermore, light saturation (L<sub>sat</sub>) increased with CO<sub>2</sub> treatments and light compensation (L<sub>cp</sub>) increased with temperature. The dark respiration (R<sub>d</sub>) increased with both temperature and CO<sub>2</sub> treatments. Markov population models suggested D. texana populations would remain ecologically similar in the future. However, sub-canopy light levels and herbivory should be considered when examining population projections. For example, Juniperus ashei juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of Quercus juveniles from reaching the canopy. These factors do not seem to be a problem for D. texana juveniles which would allow them to reach the canopy without need of a high light gap and are not prevented by herbivory. Thus, Juniperus/Quercus woodlands will change in the future to woodlands with D. texana a more common species.展开更多
基金the support and motivation provided by National 973 Project of China (No. 2012CB026104)National Natural Science Foundation of China (No. 41171064) and (No. 41271072)
文摘The mechanical property of saline soils varies with moisture and climate in the cold and salt lake region of Qinghai-Tibet Plateau, which influences project construction. In order to improve foundation reinforcement effect of the QarharvaTrolmud Highway, Qinghai Province, China, dynamic compaction replacement （DCR） composite foundation was applied in saline soils. A field experiment was conducted in this area, where strength and working mechanism of pier-soil and deformation modulus of the composite foundation was analyzed after reinforcement. This paper presents methods for determining the coefficient on the bearing capacity evaluation and deformation modulus of composite foundation with DC1L Reinforcement case of DCR is highly effective in saline soils of the salt lake regions, which helps the mi-tion of water and salt in saline soils.
文摘Diospyros texana (Texas persimmon) is a secondary species in most Juniperus ashei/Quercus fusiformis woodlands in central Texas. It has high density, but plants are mostly in the community understory. Light response curves at ambient and elevated levels of CO<sub>2</sub> and temperature were measured for D. texana. The A<sub>net</sub> (photosynthetic rate) increased significantly as both light level and CO<sub>2</sub> levels increased but not temperature. The A<sub>max</sub> (maximum photosynthetic rate) of D. texana in full sun at elevated levels of CO<sub>2</sub> was increased for all treatments. Stomatal conductance increased with levels of CO<sub>2</sub> but only if the interaction was removed from the model. Intercellular levels of CO<sub>2</sub> increased with both temperature and CO<sub>2</sub> treatments as did water use efficiency (WUE). Furthermore, light saturation (L<sub>sat</sub>) increased with CO<sub>2</sub> treatments and light compensation (L<sub>cp</sub>) increased with temperature. The dark respiration (R<sub>d</sub>) increased with both temperature and CO<sub>2</sub> treatments. Markov population models suggested D. texana populations would remain ecologically similar in the future. However, sub-canopy light levels and herbivory should be considered when examining population projections. For example, Juniperus ashei juveniles are not recruited into any canopy unless there are high light levels. Herbivory reduces the success of Quercus juveniles from reaching the canopy. These factors do not seem to be a problem for D. texana juveniles which would allow them to reach the canopy without need of a high light gap and are not prevented by herbivory. Thus, Juniperus/Quercus woodlands will change in the future to woodlands with D. texana a more common species.
