Based on the movement regularity of surrounding rock with road-in packing of gob-side entry retaining in fully-mechanized sub-level caving face(RPGERFCF),the me- chanical model of its surrounding rock was established ...Based on the movement regularity of surrounding rock with road-in packing of gob-side entry retaining in fully-mechanized sub-level caving face(RPGERFCF),the me- chanical model of its surrounding rock was established and the calculating formulas of the deformation of the roof,coal wall and filling body were attained.By the mechanical analy- sis to the deformation of the surrounding rock of RPGERFCF,the major factors influencing the deformation of the surrounding rock were found out and the technologic approaches reduced the deformation and enhanced the stability of the surrounding rock were put for- ward.Consequently,the scientific bases were provided for the stability control of the sur- rounding rock of RPGERFCF.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 National Science Foundation of China(50674046)National Science Important Foundation(50634050)Hunan Science Foundation(06JJ50092)
文摘Based on the movement regularity of surrounding rock with road-in packing of gob-side entry retaining in fully-mechanized sub-level caving face(RPGERFCF),the me- chanical model of its surrounding rock was established and the calculating formulas of the deformation of the roof,coal wall and filling body were attained.By the mechanical analy- sis to the deformation of the surrounding rock of RPGERFCF,the major factors influencing the deformation of the surrounding rock were found out and the technologic approaches reduced the deformation and enhanced the stability of the surrounding rock were put for- ward.Consequently,the scientific bases were provided for the stability control of the sur- rounding rock of RPGERFCF.
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.
