The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the ...The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the aeolian sandy soil in different ratios. Two-year-old Pinus sylvestris var. mongolica seedlings and plastic pots were used in the experiment. The experimental results indicated that: 1) the peat and weathered coal could significantly improve the physical and chemical prop-erties of aeolian sandy soil, and thus promoted the growth of seedlings; 2) the effect of peat on seedling growth, including height, base diameter, root length and biomass, presented an order of 8%>10%>5%>2%>0 in terms of peat contents, and the effect of weathered coal on seedling growth presented an order of 5%>8%>10%>2%>0 in terms of weathered coal contents for height and basal diameter, 5%>8%>2% >10%>0 for root length, and 5%>2%>8% >10%>0 for biomass; 3) the effects of peat were generally greater than that of weathered coal. Meanwhile, 8% peat was the best treatment to promote the growth of P. sylvestris var. mongolica seedlings.展开更多
Influenced by neo-tectonic movement, the Sanhu area of China＇s Qaidam Basin formed in the Quaternary in response to migration of its depocentre. A study of core material from the Qijia 1 Well reveals novel Quaternary...Influenced by neo-tectonic movement, the Sanhu area of China＇s Qaidam Basin formed in the Quaternary in response to migration of its depocentre. A study of core material from the Qijia 1 Well reveals novel Quaternary aqueously deposited aeolian sandstones in the Qigequan Formation of the Sanhu area. Here we report the sedimentary petrology and geochemistry data of these deposits that constrain their depositional history. Evidence for aeolian influence during deposition includes： sorting and roundness, pure quartz sand with single mode grain size distribution and few suspension materials,very fine sand grain size distribution indicating sorting by saltation and suspension transport, dish-shaped and crescentshaped pits in grain surfaces indicating aeolian transport and chemical composition similar to that observed in active or recent dune deposits, namely enrichment in Si O_2, Na_2 O, and Mg O relative to the sand dam sediment in the lakeshore.Identification of these aqueously deposited aeolian sandstones expands the range of sedimentary deposit types found in the Sanhu area and improves understanding of its paleoclimatic history.展开更多
We used computational fluid dynamics(CFD) and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex.Firstly,we obtained the wind po...We used computational fluid dynamics(CFD) and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex.Firstly,we obtained the wind power inputs using CFD theory.The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests.Then a new aeolian excitation was derived using the wind power equivalent principle,and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account.Secondly,we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method.The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps.Finally,the semi-analytical solution can be solved by iterative methods.Taking a 1 000 kV Ultra High Voltage transmission line as an example,we analyzed the line with and without dampers by the semi-analytical solution.Compared with the results which were computed by the energy balance method,the semi-analytical solution is precise enogh for aeolian vibration analyses.Besides,we also analyzed the influence of damper position and quantity.展开更多
Long span ultra-high voltage(UHV) transmission lines have serious aeolian vibration problems. To control these vibrations,we improved the energy balance method in the following aspects:the wind power input,the conduct...Long span ultra-high voltage(UHV) transmission lines have serious aeolian vibration problems. To control these vibrations,we improved the energy balance method in the following aspects:the wind power input,the conductor self-damping,and the damper dissipated power. Meanwhile,we built a theoretical mechanical model of β wire dampers and derived energy dissipation calculation formulae. This permits the vibration energy dissipated by β wire dampers can be considered in the energy balance method. Then,we developed a computer program based on the improved energy balance method using Matlab,and analyzed UHV long span ground wires of the Han River long span project in P. R. China. The results show that the combination of β wire dampers and Stockbridge dampers can reduce vibration of UHV long span transmission lines,which provides a reference for research and construction of UHV engineering projects.展开更多
基金This research was supported by Key Knowledge Innova-tion Project (SCXZD0102) of Institute of Applied Ecology Chinese Academy of Sciences and sponsored by the Science and Technology Department of Inner Mongolia Autonomic Region,P. R. China (2001010)
文摘The experiment was conducted at the Ganqika Sandy Land Ecological Station in Ke抏rqinzuoyihouqi County, Inner Mongolia, in a growing season from April 28 to October 28, 2001. Peat and weathered coal were added to the aeolian sandy soil in different ratios. Two-year-old Pinus sylvestris var. mongolica seedlings and plastic pots were used in the experiment. The experimental results indicated that: 1) the peat and weathered coal could significantly improve the physical and chemical prop-erties of aeolian sandy soil, and thus promoted the growth of seedlings; 2) the effect of peat on seedling growth, including height, base diameter, root length and biomass, presented an order of 8%>10%>5%>2%>0 in terms of peat contents, and the effect of weathered coal on seedling growth presented an order of 5%>8%>10%>2%>0 in terms of weathered coal contents for height and basal diameter, 5%>8%>2% >10%>0 for root length, and 5%>2%>8% >10%>0 for biomass; 3) the effects of peat were generally greater than that of weathered coal. Meanwhile, 8% peat was the best treatment to promote the growth of P. sylvestris var. mongolica seedlings.
基金funding support from the Qinghai Oilfield Company of the China National Petroleum Corporation
文摘Influenced by neo-tectonic movement, the Sanhu area of China＇s Qaidam Basin formed in the Quaternary in response to migration of its depocentre. A study of core material from the Qijia 1 Well reveals novel Quaternary aqueously deposited aeolian sandstones in the Qigequan Formation of the Sanhu area. Here we report the sedimentary petrology and geochemistry data of these deposits that constrain their depositional history. Evidence for aeolian influence during deposition includes： sorting and roundness, pure quartz sand with single mode grain size distribution and few suspension materials,very fine sand grain size distribution indicating sorting by saltation and suspension transport, dish-shaped and crescentshaped pits in grain surfaces indicating aeolian transport and chemical composition similar to that observed in active or recent dune deposits, namely enrichment in Si O_2, Na_2 O, and Mg O relative to the sand dam sediment in the lakeshore.Identification of these aqueously deposited aeolian sandstones expands the range of sedimentary deposit types found in the Sanhu area and improves understanding of its paleoclimatic history.
基金Funded by the National Natural Science Foundation of China (No.50878093)the State Grid Company of China under Grant No. [2007]413. This support is greatly appreciated.
文摘We used computational fluid dynamics(CFD) and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex.Firstly,we obtained the wind power inputs using CFD theory.The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests.Then a new aeolian excitation was derived using the wind power equivalent principle,and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account.Secondly,we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method.The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps.Finally,the semi-analytical solution can be solved by iterative methods.Taking a 1 000 kV Ultra High Voltage transmission line as an example,we analyzed the line with and without dampers by the semi-analytical solution.Compared with the results which were computed by the energy balance method,the semi-analytical solution is precise enogh for aeolian vibration analyses.Besides,we also analyzed the influence of damper position and quantity.
基金Funded by the Natural Science Foundation of China (No. 50878093).
文摘Long span ultra-high voltage(UHV) transmission lines have serious aeolian vibration problems. To control these vibrations,we improved the energy balance method in the following aspects:the wind power input,the conductor self-damping,and the damper dissipated power. Meanwhile,we built a theoretical mechanical model of β wire dampers and derived energy dissipation calculation formulae. This permits the vibration energy dissipated by β wire dampers can be considered in the energy balance method. Then,we developed a computer program based on the improved energy balance method using Matlab,and analyzed UHV long span ground wires of the Han River long span project in P. R. China. The results show that the combination of β wire dampers and Stockbridge dampers can reduce vibration of UHV long span transmission lines,which provides a reference for research and construction of UHV engineering projects.
