Based on the refraction-diffraction theory of irregular waves in the waters of slowly-varying currents and depths, and the generation dissipation theory of wind wave, a model for nonlinear irregular waves in coastal a...Based on the refraction-diffraction theory of irregular waves in the waters of slowly-varying currents and depths, and the generation dissipation theory of wind wave, a model for nonlinear irregular waves in coastal area is developed. In light of the specific conditions of coastal wave character and engineering application, a practical mathematical model for the nonlinear irregular waves is presented, with directional spectrum in coastal area. Coast effect, refraction, whitecapping, bottom friction, current, wind and nonlinear action are considered in this model. The numerical methods and schemes for wave refraction ray, energy conservation of propagation, energy balance of the generation and dissipation of wind waves have been studied. Finally, the model is used for the directional wave spectrum computation in the Daya Bay. Compared with the measured data with 956 wave bouys in the Daya Bay, the model results are in good agreement with the measured results.展开更多
Extension and growth index show that the strength of fault movement of the Bijialing area in the early Tertiary had a migration from southwest to northeast.Tectonism controlled the formation, type and distribution of ...Extension and growth index show that the strength of fault movement of the Bijialing area in the early Tertiary had a migration from southwest to northeast.Tectonism controlled the formation, type and distribution of the sedimentary system.In the Sha－ 1 and Sha－ 2 time (the first and second time－ stratigraphic ages of the Shahejie Formation),strong movement along No.1 fault induced the fan delta deposition.Movements along No.1 fault in the early Dong－ 3 time (the third time zone of the Dongying Formation deposition) got weak, and movement along No.2 and No.3 faults became strong.These structural changes caused fan delta facies and braided river facies to be distributed in the southeast.In the later Dong－ 3 time,movement along No.1 fault was mostly weak,and intense movement along No.2 fault caused the braided river facies which was mainly distributed in the northeast.展开更多
The paper systematically deals with the background of regional isotopic compo-sitions in the lower and middle reaches of the Yangtze River and neighbouring areas. It isshown that the lead isotopic compositions of diff...The paper systematically deals with the background of regional isotopic compo-sitions in the lower and middle reaches of the Yangtze River and neighbouring areas. It isshown that the lead isotopic compositions of different geological formations and units are con-trolled by the primary mantle heterogeneity, dynamic process of crust-mantle interchange,abundances of uraninm, thorium and lead of various layers of the earth and timing. Studies onthe background of regional isotopic compositions may offer significant information forgeochemical regionalization, tracing of sources of ore-forming materials, and regionalprognosis of ore deposits.展开更多
基金Chinese Academy of Sciences:the"Ninth Five-Year Plan"important resourcesenvironment research project"pipeline in seabed"(No.KZ951-A1-405)alse by the Chinese"Ninth Five-Year Plan"strategic research project"examinacion in Nansha Islands"(N
文摘Based on the refraction-diffraction theory of irregular waves in the waters of slowly-varying currents and depths, and the generation dissipation theory of wind wave, a model for nonlinear irregular waves in coastal area is developed. In light of the specific conditions of coastal wave character and engineering application, a practical mathematical model for the nonlinear irregular waves is presented, with directional spectrum in coastal area. Coast effect, refraction, whitecapping, bottom friction, current, wind and nonlinear action are considered in this model. The numerical methods and schemes for wave refraction ray, energy conservation of propagation, energy balance of the generation and dissipation of wind waves have been studied. Finally, the model is used for the directional wave spectrum computation in the Daya Bay. Compared with the measured data with 956 wave bouys in the Daya Bay, the model results are in good agreement with the measured results.
文摘Extension and growth index show that the strength of fault movement of the Bijialing area in the early Tertiary had a migration from southwest to northeast.Tectonism controlled the formation, type and distribution of the sedimentary system.In the Sha－ 1 and Sha－ 2 time (the first and second time－ stratigraphic ages of the Shahejie Formation),strong movement along No.1 fault induced the fan delta deposition.Movements along No.1 fault in the early Dong－ 3 time (the third time zone of the Dongying Formation deposition) got weak, and movement along No.2 and No.3 faults became strong.These structural changes caused fan delta facies and braided river facies to be distributed in the southeast.In the later Dong－ 3 time,movement along No.1 fault was mostly weak,and intense movement along No.2 fault caused the braided river facies which was mainly distributed in the northeast.
基金This study was co-supported by the State Eighth Five-Year Plan Scientific Project(No.85-901-03-08D)and National Natural Science Foundation of China(No.49473187).
文摘The paper systematically deals with the background of regional isotopic compo-sitions in the lower and middle reaches of the Yangtze River and neighbouring areas. It isshown that the lead isotopic compositions of different geological formations and units are con-trolled by the primary mantle heterogeneity, dynamic process of crust-mantle interchange,abundances of uraninm, thorium and lead of various layers of the earth and timing. Studies onthe background of regional isotopic compositions may offer significant information forgeochemical regionalization, tracing of sources of ore-forming materials, and regionalprognosis of ore deposits.
