针对偏远地区电力资源缺乏且风能充足的特点,设计了一种孤岛运行的小型风储直流微网系统。该系统采用双极性直流母线结构,降低了母线对地电压,同时满足各种变换器和负荷对不同电压等级的要求,使系统更加安全可靠。利用电压平衡器保证了...针对偏远地区电力资源缺乏且风能充足的特点,设计了一种孤岛运行的小型风储直流微网系统。该系统采用双极性直流母线结构,降低了母线对地电压,同时满足各种变换器和负荷对不同电压等级的要求,使系统更加安全可靠。利用电压平衡器保证了正负母线电压平衡,并分别设计了风力发电单元和混合储能单元(hybrid energy storage system,HESS)在不同工况下的最优工作方式。将该小型风储直流微网系统运行分为五种模式,通过对风机、混合储能以及负荷进行协调控制,确保直流母线电压的稳定和负荷的可靠供电。最后通过仿真验证了系统运行的稳定性和控制策略的可行性。展开更多
The mixed brightness-integrals were defined by Li and Zhu. In this paper, we first establish two Brunn-Minkowski ine- qualities of the mixed brightness-integrals based on the Blaschke sum and Minkowski sum of convex b...The mixed brightness-integrals were defined by Li and Zhu. In this paper, we first establish two Brunn-Minkowski ine- qualities of the mixed brightness-integrals based on the Blaschke sum and Minkowski sum of convex bodies. Further, we also obtain the Beckenbach-Dresher type inequalities of the mixed bright- ness-integrals combining the harmonic Blaschke sum and the harmonic radial sum of star bodies.展开更多
We must persevere to drill through the intact ocean crust to fully address fundamental questions towards completion of the plate tectonics theory.The primary questions include:what is the ocean crust made up of,how th...We must persevere to drill through the intact ocean crust to fully address fundamental questions towards completion of the plate tectonics theory.The primary questions include:what is the ocean crust made up of,how thick is it and what is the petrological nature of the crust-mantle boundary(i.e.,Mohorovičićdiscontinuity or Moho)?These questions may sound naive because they are widely believed to be well-understood facts,but they are not.Correctly,our current knowledge remains incomplete,and some popular misperceptions come from interpretations based on convenient assumptions.One assumption is that the ocean crust inferred from seismic data is of magmatic origin.Testing this assumption is a principal motivation of Project Mohole(1957-1966),attempting to drill intact ocean crust across the Moho into the mantle.Project Mohole failed because of its high cost,engineering challenges and insufficient tries,but the technologies developed made subsequent ocean drilling successful.However,answers to the original questions remain unsatisfactory.For example,seismic crust interpreted to be of magmatic origin is shown to have globally uniform thickness of 6.0±1.0 km,but crust with such thickness at many slow-spreading ridge segments is dominated by serpentinized mantle peridotites exposed on seafloors.Therefore,the popular view on ocean ridge magmatism must be re-examined,which needs intact ocean crust drilling into the mantle.Drilling at geologically simple sites in the fast-spreading Pacific seafloor is most promising.The US-led D/V JOIDES Resolution that has well served the scientific ocean drilling since 1985 is to retire by the end of 2024,but timely the Chinese geoscience community wishes to continue this international endeavor using the purpose-built D/V Meng Xiang to be in service in 2025.The international community is to gather in November 24-27,2024,Guangzhou,China,to discuss strategies on where and how to successfully drill intact ocean crust across the Moho in coming years.展开更多
文摘针对偏远地区电力资源缺乏且风能充足的特点,设计了一种孤岛运行的小型风储直流微网系统。该系统采用双极性直流母线结构,降低了母线对地电压,同时满足各种变换器和负荷对不同电压等级的要求,使系统更加安全可靠。利用电压平衡器保证了正负母线电压平衡,并分别设计了风力发电单元和混合储能单元(hybrid energy storage system,HESS)在不同工况下的最优工作方式。将该小型风储直流微网系统运行分为五种模式,通过对风机、混合储能以及负荷进行协调控制,确保直流母线电压的稳定和负荷的可靠供电。最后通过仿真验证了系统运行的稳定性和控制策略的可行性。
基金Supported by the National Natural Science Foundation of China(11371224)Foundation of Degree Dissertation of Master of China Three Gorges University(2013PY068)
文摘The mixed brightness-integrals were defined by Li and Zhu. In this paper, we first establish two Brunn-Minkowski ine- qualities of the mixed brightness-integrals based on the Blaschke sum and Minkowski sum of convex bodies. Further, we also obtain the Beckenbach-Dresher type inequalities of the mixed bright- ness-integrals combining the harmonic Blaschke sum and the harmonic radial sum of star bodies.
基金supported by grants from NSFC(91958215)Shandong Basic Research Office(WSR2023018)the Ministry of Education 111 Project(B18048).
文摘We must persevere to drill through the intact ocean crust to fully address fundamental questions towards completion of the plate tectonics theory.The primary questions include:what is the ocean crust made up of,how thick is it and what is the petrological nature of the crust-mantle boundary(i.e.,Mohorovičićdiscontinuity or Moho)?These questions may sound naive because they are widely believed to be well-understood facts,but they are not.Correctly,our current knowledge remains incomplete,and some popular misperceptions come from interpretations based on convenient assumptions.One assumption is that the ocean crust inferred from seismic data is of magmatic origin.Testing this assumption is a principal motivation of Project Mohole(1957-1966),attempting to drill intact ocean crust across the Moho into the mantle.Project Mohole failed because of its high cost,engineering challenges and insufficient tries,but the technologies developed made subsequent ocean drilling successful.However,answers to the original questions remain unsatisfactory.For example,seismic crust interpreted to be of magmatic origin is shown to have globally uniform thickness of 6.0±1.0 km,but crust with such thickness at many slow-spreading ridge segments is dominated by serpentinized mantle peridotites exposed on seafloors.Therefore,the popular view on ocean ridge magmatism must be re-examined,which needs intact ocean crust drilling into the mantle.Drilling at geologically simple sites in the fast-spreading Pacific seafloor is most promising.The US-led D/V JOIDES Resolution that has well served the scientific ocean drilling since 1985 is to retire by the end of 2024,but timely the Chinese geoscience community wishes to continue this international endeavor using the purpose-built D/V Meng Xiang to be in service in 2025.The international community is to gather in November 24-27,2024,Guangzhou,China,to discuss strategies on where and how to successfully drill intact ocean crust across the Moho in coming years.
