���������CHAMP�������ָ��е�Ӧ��     

徐天河  贺凯飞 《大地测量与地球动力学》2008,28(2):81-85

??????????CHAMP?????????????????????????????н?????1???????????С?????LS??????????CHAMP?????????????????????????????????????????????????????????????????????????????????????CHAMP??????????У???????????????????????????1?GFZ????????????1???? CHAMP????RSO????????????????????????20???????(5??100) m ²s ^-2??С??????????????LS????????????60??60???????????????????EIGEN??CG03C??EIGEN2???????б?????????????????????Ч?????????????????CHAMP????????????????????LS???????????????ε?EGM96??EIGEN1S??EIGEN2????  相似文献   

Numerical Analysis on the Effects of Submerged Depth of the Grid and Direction of Incident Wave on Gravity Cage   总被引：1，自引：0，他引：1  

陈昌平  李玉成  赵云鹏  董国海  桂福坤 《中国海洋工程》2009,23(2):233-250

In this paper,the numerical model of the net cage with the grid mooring system in waves is set up by the lumped mass method and rigid kinematics theory,and then the motion equations of floating system,net system,mooring system,and floaters are solved by the Runge-Kutta fifth-order method.For the verification of the numerical model,a series of physical model tests have been carried out.According to the comparisons between the simulated and experimental results,it can be found that the simulated and experimental results agree well in each condition.Then,the effects of submerged depth of grid and direction of incident wave propagation on hydrodynamic behaviors of the net cage are analyzed.According to the simulated results,it can be found that with the increase of submerged depth of grid,the forces acting on mooring lines and bridle lines increase,while the forces on grid lines decrease;the horizontal motion amplitudes of floating collar decrease obviously,while the vertical motion amplitudes of floating collar change little.When the direction of incident wave propagation changes,forces on mooting lines and motion of net cage also change accordingly.When the propagation direction of incident wave changes from 0° to 45°,forces on the main ropes and bridle ropes increase,while the forces on the grid ropes decrease.With the increasing propagation direction of incident wave,the horizontal amplitude of the forces collar decreases,while the vertical amplitude of the floating collar has little variation.  相似文献   

企鹅珍珠贝人工养殖及育珠的研究   总被引：1，自引：0，他引：1  

符韶  邓陈茂  梁飞龙  黄海立  谢仁政 《广东海洋大学学报》2007,27(1):34-37

在幼贝中间养成中采用柱形笼养殖法,母贝的养成中采用穿耳开放式养殖法,与全程采用锥形笼的传统式养殖方法相比较,进行企鹅珍珠贝人工养殖。结果表明:采用本技术养殖企鹅珍珠贝,在幼贝中间养成阶段,比传统养殖的壳高生长速率提高32·1%(P<0·05),壳长生长速率提高30·3%(P<0·01),成活率提高36%(P<0·01);母贝养成阶段,比传统养殖的壳高生长速率提高28·1%(P<0·05),壳长生长速率提高26·7%(P<0·01),成活率提高18·3%(P<0·01)。同时进行企鹅珍珠贝人工培育游离珠实验,植核贝在休养期和育珠期存活率分别为71·2%和54·3%,留核率分别为29·6·6%和21·0%,成珠率58·6%,优质珠比例为26·7%。  相似文献   

Numerical Study on the Hydrodynamic Characteristics of Biofouled Full-Scale Net Cage     

毕春伟  赵云鹏  董国海 《海洋工程》2015,29(3):401-414

The effect of biofouling on the hydrodynamic characteristics of the net cage is of particular interest as biofouled nettings can significantly reduce flow of well-oxygenated water reaching the stocked fish. For computational efficiency, the porous-media fluid model is proposed to simulate flow through the biofouled plane net and full-scale net cage. The porous coefficients of the porous-media fluid model can be determined from the quadratic-function relationship between the hydrodynamic forces on a plane net and the flow velocity using the least squares method. In this study, drag forces on and flow fields around five plane nets with different levels of biofouling are calculated by use of the proposed model. The numerical results are compared with the experimental data of Swift et al. (2006) and the effectiveness of the numerical model is presented. On that basis, flow through full-scale net cages with the same level of biofouling as the tested plane nets are modeled. The flow fields inside and around biofouled net cages are analyzed and the drag force acting on a net cage is estimated by a control volume analysis method. According to the numerical results, empirical formulas of reduction in flow velocity and load on a net cage are derived as function of drag coefficient of the corresponding biofouled netting.  相似文献   

Reconstruction and prediction of the total solar irradiance: From the Medieval Warm Period to the 21st century     

《New Astronomy》2015

  相似文献   

��̬�Ƚ�֧���������ڴ�ӱ���Ԥ���е�Ӧ��   总被引：2，自引：2，他引：0  

李潇  徐进军 《大地测量与地球动力学》2009,29(2):118-120

???????????????????????и?????????С???????????????????????????????LS??SVM?????????????????????????????????????????????????????????????μ???LS??SVM??????????????γ??????LS??SVM??????????????д???????????????????Ч????  相似文献   

����-֧���������ڴ�Ӱ�ȫ���Ԥ���е�Ӧ��   总被引：5，自引：3，他引：2  

赵卿  李潇  徐进军  宓天跃 《大地测量与地球动力学》2008,28(2):115-119

????????????????????г?????????????????μ?????????-??????????????????????????????????????????????????????????????????????????????????????????????????????????С????????????????н???????г????????????????????Ч????á?  相似文献   

变步长显式完全平方守恒差分格式   总被引：8，自引：0，他引：8  

王斌  季仲贞 《气象学报》1995,53(3):299-305

综合隐式完全平方守恒差分格式和显式瞬时平方守恒差分格式的优点，针对一类非线性发展方程构造了一种通过自动调节时间步长来保持平方守恒性的显式差分格式。它基于加小耗散的思想，但又与小耗散法有所不同。本文取的耗散项不是一般的人工耗散，而是取能够弥补由于时间离散所产生的截断误差的所谓（时间）协调耗散。因此，该格式具有较高的时间精度。在数值试验中，该类格式可取得满意的效果。  相似文献   

Three-dimensional analysis of vertical square anchor plate in cohesionless soil     

Awdhesh Kumar Choudhary  Bhardwaj Pandit  G. L. Sivakumar Babu 《Geomechanics and Geoengineering》2020,15(1):1-9

ABSTRACT

Vertical anchor plates are often provided to increase the performance of various geotechnical engineering structures such as sheet pile walls, bulkheads, bridge abutments and offshore structures. Hence, the safe design of such structures needs a better understanding of the 3D behaviour of the anchor plate. This paper presents and discusses the results obtained from a series of 3D finite-difference analyses of vertical square anchor plate embedded in cohesionless soil. The 3D model is found to closely predict experimental pullout load–displacement relationship. The failure mechanism observed in the numerical model is found to be very similar to the failure reported in experimental studies. For a given embedment depth, the stiffness of the breakout factor–displacement response substantially reduces with increase in anchor plate size. However, the ultimate reduction in anchor capacity is found to approximately 8% with an increase in anchor size from 0.1 to 1 m. Numerical analysis reveals that at deeper embedment depth, the friction angle of sand is the critical parameter in enhancing the performance of anchor plate. The obtained 3D model results are then compared with the published results and are found to be reasonably in good agreement with each other.  相似文献   

高次差法求解时间序列中趋势项的方法研究及其应用   总被引：1，自引：0，他引：1  

石双忠  岳东杰  李蕾蕾 《现代测绘》2004,27(1):14-16

介绍了高次差法求解时间序列中趋势项的基本原理与方法。通过实例对某沉降监测点的观测序列进行分析处理、预报，并与最小二乘法进行了比较，结果表明该法在建模的精度、抵抗粗差等方面均优于最小二乘法。可应用于时间序列中趋势项的求解与多项式回归分析。  相似文献