The coast of southern Hainan Island is characterized by wide sandy embayments, which consist of ( i) drowned valleys bounded by steep bedrock hills and only locally receiving sediments, and embayments of various dimen...The coast of southern Hainan Island is characterized by wide sandy embayments, which consist of ( i) drowned valleys bounded by steep bedrock hills and only locally receiving sediments, and embayments of various dimensions covered either by (ii) alluvial-deltaic deposits or by (iii) sands of coastal beach ridges/barriers and associated elongated lagoons. During the late Tertiary-Pleistocene the area has experienced isostatic and eustatic movements associated with neotectonics and climatic changes. Such history isrecorded in terraces at various altitudes (SO, 40, 20 m asl) and sequences of coastal sand ridges/baymouth bars. The Holocene variations in sea level and climate are recorded in the dated coastal ridges, coral reef and beachrock. Conditions suitable for reef development started about 8000 a BP. The GPR profiles also show that the internal structures of the sand ridges have composite nature being formed by several superimposed secondary ridges.展开更多
According to the landscape/land use relation of southern Hainan Island, four main zones are considered: the mountain and high hill zone, the inner coastal zone, the shoreline zone and the marine zone. The economic boo...According to the landscape/land use relation of southern Hainan Island, four main zones are considered: the mountain and high hill zone, the inner coastal zone, the shoreline zone and the marine zone. The economic boom has led to an increase in urbanization and development of tourism, at times harming the local environment.展开更多
海底电缆过电压与绝缘配合问题是跨海电力联网工程设计的重要内容,也是开展海底电缆结构设计的前提[1]。南方主网与海南电网联网工程是我国首条、世界第二条500 k V交流海底电缆,其绝缘配合设计直接关系到工程运行安全性和总投资,故而...海底电缆过电压与绝缘配合问题是跨海电力联网工程设计的重要内容,也是开展海底电缆结构设计的前提[1]。南方主网与海南电网联网工程是我国首条、世界第二条500 k V交流海底电缆,其绝缘配合设计直接关系到工程运行安全性和总投资,故而尤为重要。从联网系统工频过电压、操作过电压和雷电过电压的角度,对海底电缆可能出现的各种过电压水平进行分析和仿真计算,根据计算结果对系统、一次主接线提出降低海底电缆过电压的措施。结合电缆过电压水平,计算电缆所需的绝缘厚度值,并对工频耐受电压、冲击耐受电压水平进行校核。最后,对提高海底电缆绝缘安全性能的措施提出建议,研究结果可为其他海底电缆工程的设计提供参考。展开更多
基金Concerned research works have got the powerful support from State Pilot Laboratory of Coast & Island Exploitation, Nanjing University, Most staffs from this lab have joined the series of fieldwork, and also done many kinds of indoor analyses. Recent stud
文摘The coast of southern Hainan Island is characterized by wide sandy embayments, which consist of ( i) drowned valleys bounded by steep bedrock hills and only locally receiving sediments, and embayments of various dimensions covered either by (ii) alluvial-deltaic deposits or by (iii) sands of coastal beach ridges/barriers and associated elongated lagoons. During the late Tertiary-Pleistocene the area has experienced isostatic and eustatic movements associated with neotectonics and climatic changes. Such history isrecorded in terraces at various altitudes (SO, 40, 20 m asl) and sequences of coastal sand ridges/baymouth bars. The Holocene variations in sea level and climate are recorded in the dated coastal ridges, coral reef and beachrock. Conditions suitable for reef development started about 8000 a BP. The GPR profiles also show that the internal structures of the sand ridges have composite nature being formed by several superimposed secondary ridges.
文摘According to the landscape/land use relation of southern Hainan Island, four main zones are considered: the mountain and high hill zone, the inner coastal zone, the shoreline zone and the marine zone. The economic boom has led to an increase in urbanization and development of tourism, at times harming the local environment.
文摘海底电缆过电压与绝缘配合问题是跨海电力联网工程设计的重要内容,也是开展海底电缆结构设计的前提[1]。南方主网与海南电网联网工程是我国首条、世界第二条500 k V交流海底电缆,其绝缘配合设计直接关系到工程运行安全性和总投资,故而尤为重要。从联网系统工频过电压、操作过电压和雷电过电压的角度,对海底电缆可能出现的各种过电压水平进行分析和仿真计算,根据计算结果对系统、一次主接线提出降低海底电缆过电压的措施。结合电缆过电压水平,计算电缆所需的绝缘厚度值,并对工频耐受电压、冲击耐受电压水平进行校核。最后,对提高海底电缆绝缘安全性能的措施提出建议,研究结果可为其他海底电缆工程的设计提供参考。
