Large-scale detachment faults on mid-ocean ridges （MORs） provide a window into the deeper earth. They have megamullion on their corrugated surfaces, with exposed lower crustal and upper mantle rocks, rela- tively hi...Large-scale detachment faults on mid-ocean ridges （MORs） provide a window into the deeper earth. They have megamullion on their corrugated surfaces, with exposed lower crustal and upper mantle rocks, rela- tively high residual Bouguer gravity anomaly and P-wave velocity, and are commonly associated with ocean- ic core complex. According to 30 detachment faults identified on MORs, we found that their distances to the axis mostly range from 5 to 50 km, half-spreading rates range from 6.8 to 17 mm/a, and activity time ranges from recent to 3 Ma. Most of the detachment faults are developed on the slow spreading Mid-Atlantic Ridge （MAR） and ultra-slow spreading Southwest Indian Ridge （SWIRl, with the dominant half-spreading rates of 7-13 mm/a, especially 10-13 mm/a. Furthermore, they mostly occur at the inside corner of one segment end and result in an asymmetric seafloor spreading. The detachment faults on MORs are mainly controlled by the tectonism and influenced by the magmatism. Long-lived detachment faults tend to be formed where the ridge magma supply is at a moderate level, although the tectonism is a first-order controlling factor. At the slow spreading ridges, detachment faults tend to occur where local magma supply is relatively low, whilst at the ultra-slow spreading ridges, they normally occur where local magma supply is relatively high. These faults are accompanied by hydrothermal activities, with their relationships being useful in the study of hydrothermal polymetallic sulfides and their origin.展开更多
基于扩展频域时域反射法(Spread Spectral Time Domain Reflectometry,SSTDR)的光伏阵列故障诊断方法存在检测盲区和衰减特性,有必要研究检测信号的性质以提高故障检测性能。首先,对检测信号在光伏阵列中的传输行为进行研究,探究不同信...基于扩展频域时域反射法(Spread Spectral Time Domain Reflectometry,SSTDR)的光伏阵列故障诊断方法存在检测盲区和衰减特性,有必要研究检测信号的性质以提高故障检测性能。首先,对检测信号在光伏阵列中的传输行为进行研究,探究不同信号参数对检测范围和精度的影响;其次,根据光伏电池的动态模型和排布规律,搭建光伏阵列故障检测仿真平台,通过断路故障仿真实验对结果进行验证,结果表明,改善信号能有效增强相关峰辨识能力,使光伏组件检测数量增加4块;最后,综合考虑检测盲区和衰减特性对检测性能的影响,提出基于SSTDR的光伏阵列故障检测信号选择策略,用以确定测距范围和最优信号参数。展开更多
On the basis of field observations, the complex time-space spreading pattern and focal mechanism of the 1989Batang earthquake swarm are studied in this paper. The fault motions of the epicenter area are analysed bythe...On the basis of field observations, the complex time-space spreading pattern and focal mechanism of the 1989Batang earthquake swarm are studied in this paper. The fault motions of the epicenter area are analysed bythe leveling survey before and after strong events. From the given simplified focal mechanical model of theswarm,the process of fracture indicates that swarm strong ruptures are associated with the spreading and thevirgation of the barrier of irregularen en echelon source fault system.展开更多
The Songnen Plain lying in the central part of the Northeast China Plain covers an area of about 170 000 km2. There are vast patches of saline land, which are still in the process of enlargement. The spread of saline ...The Songnen Plain lying in the central part of the Northeast China Plain covers an area of about 170 000 km2. There are vast patches of saline land, which are still in the process of enlargement. The spread of saline land has already caused the worsening of ecoenvironment and hindered agricultural development in the region. The paper analyses background factors of natural environment that caused the spread of saline land according to the information of Landsat TM images. The result shows that among the three kinds of lakes the fault lake is the background factor of natural environment that causes the spread of saline land under arid conditions. Its lakebeach meadows could not recover from the excessive utilization in farming and stockraising. The proposed countermeasures to prevent and control the spread of saline land serve as biological steps or water conservancy facilities to protect the lakebeach meadows of the fault lakes from being artificial excessively utilized.展开更多
基金The National Natural Science Foundation of China under contract Nos 91028006 and 41206046the Dayang 115 under contact No.DYXM-115-02-3-01
文摘Large-scale detachment faults on mid-ocean ridges （MORs） provide a window into the deeper earth. They have megamullion on their corrugated surfaces, with exposed lower crustal and upper mantle rocks, rela- tively high residual Bouguer gravity anomaly and P-wave velocity, and are commonly associated with ocean- ic core complex. According to 30 detachment faults identified on MORs, we found that their distances to the axis mostly range from 5 to 50 km, half-spreading rates range from 6.8 to 17 mm/a, and activity time ranges from recent to 3 Ma. Most of the detachment faults are developed on the slow spreading Mid-Atlantic Ridge （MAR） and ultra-slow spreading Southwest Indian Ridge （SWIRl, with the dominant half-spreading rates of 7-13 mm/a, especially 10-13 mm/a. Furthermore, they mostly occur at the inside corner of one segment end and result in an asymmetric seafloor spreading. The detachment faults on MORs are mainly controlled by the tectonism and influenced by the magmatism. Long-lived detachment faults tend to be formed where the ridge magma supply is at a moderate level, although the tectonism is a first-order controlling factor. At the slow spreading ridges, detachment faults tend to occur where local magma supply is relatively low, whilst at the ultra-slow spreading ridges, they normally occur where local magma supply is relatively high. These faults are accompanied by hydrothermal activities, with their relationships being useful in the study of hydrothermal polymetallic sulfides and their origin.
文摘基于扩展频域时域反射法(Spread Spectral Time Domain Reflectometry,SSTDR)的光伏阵列故障诊断方法存在检测盲区和衰减特性,有必要研究检测信号的性质以提高故障检测性能。首先,对检测信号在光伏阵列中的传输行为进行研究,探究不同信号参数对检测范围和精度的影响;其次,根据光伏电池的动态模型和排布规律,搭建光伏阵列故障检测仿真平台,通过断路故障仿真实验对结果进行验证,结果表明,改善信号能有效增强相关峰辨识能力,使光伏组件检测数量增加4块;最后,综合考虑检测盲区和衰减特性对检测性能的影响,提出基于SSTDR的光伏阵列故障检测信号选择策略,用以确定测距范围和最优信号参数。
文摘On the basis of field observations, the complex time-space spreading pattern and focal mechanism of the 1989Batang earthquake swarm are studied in this paper. The fault motions of the epicenter area are analysed bythe leveling survey before and after strong events. From the given simplified focal mechanical model of theswarm,the process of fracture indicates that swarm strong ruptures are associated with the spreading and thevirgation of the barrier of irregularen en echelon source fault system.
文摘The Songnen Plain lying in the central part of the Northeast China Plain covers an area of about 170 000 km2. There are vast patches of saline land, which are still in the process of enlargement. The spread of saline land has already caused the worsening of ecoenvironment and hindered agricultural development in the region. The paper analyses background factors of natural environment that caused the spread of saline land according to the information of Landsat TM images. The result shows that among the three kinds of lakes the fault lake is the background factor of natural environment that causes the spread of saline land under arid conditions. Its lakebeach meadows could not recover from the excessive utilization in farming and stockraising. The proposed countermeasures to prevent and control the spread of saline land serve as biological steps or water conservancy facilities to protect the lakebeach meadows of the fault lakes from being artificial excessively utilized.
