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101.
西天山阿吾拉勒埃达克质岩石成因:Nd和Sr同位素组成的限制 总被引:28,自引:11,他引:28
西天山阿吾拉勒二叠纪钠质英安岩和钠长斑岩具有与埃达克岩一致的高Sr,低Y、Yb和Eu正异常等独特岩石地球化学特征。系统的Nd和Sr同位素组成研究表明,其(^143Nd/^144Nd)i为0.512384-0.512470,εNd(t)为正值(+1.57-+3.26);(^87Sr/^86Sr)i为0.0751-0.7054,与本区同时代幔源玄武岩的Nd和Sr同位素组成特征相似,但与俯冲洋壳部分熔融成因埃达克岩的Nd和Sr同位素组成有显著区别。结合这些埃达克质岩石形成二叠纪后碰撞阶段构造背景,认为本区埃达克质岩浆最有可能由新底侵的玄武质下地壳在角闪岩相向榴辉岩相过渡或榴辉岩相的条件下部分熔融形成,是西天山晚古生代后碰撞阶段地幔玄武岩浆底侵作用和地壳垂向增生的重要岩石标志。 相似文献
102.
103.
A numerical model for shallow water flow has been developed based on the unsteady Reynolds-averaged Navier-Stokes equations with the hydrodynamic pressure instead of hydrostatic pressure assumption. The equations arc transformed into the a-coordinate system and the eddy viscosity is calculated with the standard k -ε turbulence model. The control volume method is used to discrete the equations, and the boundary conditions at the bed for shallow water models only include vertical diffusion terms expressed with wall functions. And the semi-implicit methed for pressure linked equation arithmetic is adopted to solve the equations. The model is applied to the 2D vertical plane flow of a current over two steep-sided trenches for which experiment data are available for comparison and good agreement is obtained. And the model is used to predicting the flow in a channel with a steep-sided submerged breakwater at the bottom, and the streamline is drawn. 相似文献
104.
105.
南海海面温度的年际模态及其与季风强迫的关系 总被引:1,自引:0,他引:1
通过对COADS和OISST海洋气象资料的分析,以南海的海面温度异常(SSTA)为指示因子,在研究年际尺度上的南海与大尺度ENSO关系的基础上,进一步探讨了季风强迫下Ekman抽吸对SSTA年际变化的贡献。研究发现,南海SSTA滞后5个月时与:Nifio 3的SSTA相关系数最大,且其年际变化依方差贡献大小,分别有42.7月、25.6月及36.6个月的周期,这3个年际模态基本上能够描述海面温度的年际变异,为南海在大尺度ENSO背景下存在区域响应提供了重要的证据;应用Krause—Turner混合层温度方程对南海异常暖事件的研究表明,除了经向风应力异常,Ekman抽吸也是影响SSTA年际变异的主要因素,在某些异常年份甚至是主导因素,为南海SSTA年际变化的研究提供了重要的补充。 相似文献
106.
Mai Yuanjian
Senior Engineer the th Harbour Engineering Bureau The Ministry of Communications of P. R. China Guangzhou 《中国海洋工程》1997,(2)
Based on statistics and analysis of the safety factor of unstable bank slopes,the relation be-tween safety level and reliability index of stability is studied and discussed,and then the elementary cali-brating calculation is carried out to the levels of safety and reliability for bank slope stability in the rangeof safety factors stipulated in existing China Technical Specifications for Port Engineering—FoundationPart(1987)and to those reached by some stable bank slopes already built.The results show that the relia-bility index β in the effective stress method is able to reach a high value of 2.4~4.1(mid-value 3.25),while the value of β in other three kinds of total stress method can just reach a lower value of 0.5~2.8(mid-value 1.65),which are in conformity with the engineering experience in China,and thus acceptable.Some suggestions are also given in this paper to the adoption of the value of β_0—objective reliability indexfor bank slope stability. 相似文献
107.
Structural Design and Protective Methods for the 100 kW Shoreline Wave Power Station 总被引:2,自引:0,他引:2
1 .IntroductionThe 1 0 0kWshorelinewavepowerstationofChinaisanOscillatingWaterColumn (OWC)wavepowerdeviceintegratedtoanelectricgrid .ItislocatedattheZhelangTown ( 2 2°39’Nand 1 1 5°34’E) ,ShanweiCityofGuangdongProvince .Theresearchanddevelopmentofthe 1 0 0kWOWCshore linewavepowerstationissupportedbyChina′sNationalKeyTechnologiesR&DPrograminthe 9thfive yearplan .TheconstructionofthestationstartedinJune 1 998andwascompletedinFebruary2 0 0 1 .Uptonow ,ithasbeenoperatingfor2years … 相似文献
108.
Chen Jiajing Wang Dongjiao Professor South China University of Technology Guangzhou PhD Student Hong Kong Polytechnic Formerly South China University of Technology Guangzhou 《中国海洋工程》1991,(4)
A nonlinear dynamic analysis model is estabilished on the basis of "lumped mass" approach, which takes the influence of the fluid flow within the pipe into consideration. Numerical results are compared with the published works, and the effects of internal fluid flow, internal pressure, dyanmics as well as the nonlinear characteristics on the behavior of flexible risers are discussed. From this work, some useful conclusions are drawn. 相似文献
109.
Computation of Wave, Tide and Wind Current for the South China Sea Under Tropical Cyclones 总被引:1,自引:0,他引:1
Based on the third-generation oceanic wave prediction model (WAVEWATCH Ⅲ) ,the third-generation nearshore wave calculation model (SWAN) and the mathematical tide, tidal current and cyclone current model, which have been improved, interconnected and expanded, a coupled model of offshore wave, tide and sea current under tropical cyclone surges in the South China Sea has been established. The coupled model is driven by the tropical cyclone field containing the background wind field. In order to test the hindcasting effect of the mathematical model, a comparison has been made between the calculated results and the observational results of waves of 15 cyclone cases, water levels and current velocities of the of 7 cyclones. The results of verification indicate that the calculated and observed results are basically identical. 相似文献
110.
Investigation on the Oscillating Buoy Wave Power Device 总被引:4,自引:0,他引:4
An oscillating buoy wave power device (OD) is a device extracting wave power by an oscillating buoy. Being excited by waves, the buoy heaves up and down to convert wave energy into electricity by means of a mechanical or hydraulic device. Compared with an Oscillating Water Column (OWC) wave power device, the OD has the same capture vvidth ratio as the OWC does, but much higher secondary conversion efficiency. Moreover, the chamber of the OWC, which is the most expensive and difficult part to be built, is not necessary for the OD, so it is easier to construct an OD. In this paper, a nu-merical calculation is conducted for an optimal design of the OD firstly, then a model of the device is built and, a model test is carried out in a wave tank. The results show that the total efficiency of the OD is much higher than that of the OWC and that the OD is a promising wave power device. 相似文献