Wave-induced seabed response analysis by radial point interpolation meshless method

Wave-induced transient response of seabeds is numerically analyzed through a radial point interpolation meshless method (radial PIM). The Biot’s consolidation theory is employed and incorporated with virtual boundary conditions to describe this wave-induced transient response of the seabed. Displacement and pore water pressure are spatially discretized by the radial PIM with the same shape function. Compactly supported basis functions are proposed to obtain a banded system equation. Because the radial PIM passes through all nodal points within an influence domain, essential boundary conditions as well as virtual boundary conditions can be easily implemented at local level. Fully implicit integration scheme is used in time domain to avoid spurious ripple effect. The proposed algorithm is assessed through the comparison of numerical results with closed-form solution or finite element solutions.     

北黄海冷水团环流结构探讨──潮混合锋对环流结构的影响

简述北黄海冷水团环流结构研究现状，指出已有研究成果中的主要问题，然后用一个诊断模型给出了冷水团环流结构，得到冷水团环向主要存在于海洋上层接近冷水团边界处，径向运动也主要存在于断面两端，上层为离岸流，下层为向岸流；冷水团中心的上升流极为微弱，且仅存在于海洋上层，温跃层下的冷水团中心区域的流动极为微弱，几乎为“死水”一般，上述环流结构对冷水团中心部分的温、盐度长期保持不变及跃层底部溶解氧最大值的形成和     

一种基于球体分片射线的大数据体渲染方法

针对大数据量、大范围对象的体渲染效果不够精细美观的问题,文章提出了一种基于球体分片射线的体渲染方法:通过将立方体形式的数据组织转变为环绕球体的弧形数据组织方式,并对体数据依次分片,逐片进行渲染。详细论述了该方法的原理及流程,并在某四维气象演示系统的台风登陆模拟中得到了很好的验证。实验表明,该方法能有效地渲染大数据量大范围对象的细节,提高了可视化效果。     

Modeling of the radial and transverse components of the albedo function

In this work, we shall confine ourselves to solve analytically the integrals called , for the two components of albedo radiation pressure on an Earth’s satellite. When the Earth’s albedo is variable, as far as we know, this case has not been dealt with analytically. We shall solve these two integrals when the satellite’ horizon is illuminated and when the sun lies on the equator. This approach will facilitate the evaluation of the mentioned two equations. We will also compare our results with previous works obtained numerically.     

A stable meshfree method for fully coupled flow-deformation analysis of saturated porous media

A fully coupled meshfree algorithm is proposed for numerical analysis of Biot’s formulation. Spatial discretization of the governing equations is presented using the Radial Point Interpolation Method (RPIM). Temporal discretization is achieved based on a novel three-point approximation technique with a variable time step, which has second order accuracy and avoids spurious ripple effects observed in the conventional two-point Crank Nicolson technique. Application of the model is demonstrated using several numerical examples with analytical or semi-analytical solutions. It is shown that the model proposed is effective in simulating the coupled flow deformation behaviour in fluid saturated porous media with good accuracy and stability irrespective of the magnitude of the time step adopted.     

The enhanced spectrum of the symbiotic variable star CH Cygni on November 2, 2006

The symbiotic variable star CH Cygni went on the deepest minimum phase in December 2006. A high-resolution spectrum of CH Cygni obtained at the Bohyunsan Optical Astronomy Observatory (BOAO) on November 2, 2006, is reported. The spectrum of CH Cygni obtained at the BOAO was calibrated on a scale of an absolute-flux density. Emission lines of H I, [O III], [N II], and [S II] were strong, with several components, and Ca II, H, and K lines had P-Cygni profiles. Removal of the spectrum of the underlying M-type star from the CH Cygni spectrum was completed to obtain the true emission profiles. The radial velocities of all emission and absorption lines were measured. Some of the observed lines were also deconvoluted using multi-Gaussian functions to find the relationship between line shapes and the corresponding sources of these lines. The results obtained are discussed in terms of an accretion disk around the hot star, and in non-spherically extended nebular regions.     

轻便可控震源在金属矿地震反射勘探的试验研究

在河北省迁安大石河铁矿进行轻便高频可控源 (PHV)地震反射勘探的试验研究是成功的。可控震源的优点主要在于分辨率高、可以自由选择频率范围 ,对输入到地下能量的频谱有一定的控制作用。通过与夯击震源WACKERBS60Y系统结果的对比 ,证实了它工作稳定 ,效率高 ,优于其它震源。     

地图数字注记识别的神经网络方法

讨论了基于径向基函数网络（RBFN）的地图数字注记识别问题。在分析了网络结构和训练算法的基础上,用地回扫描数据进行了识别实验。结果表明,本文提出的方法用于地图数字注记识别是非常有效的。     

EXPERIMENTAL STUDY ON FLOW AND SEDIMENT MOVEMENT IN CAVITY CIRCULATIONS

1 INTRODUCTION Cavity channels are often found in harbor basins, waterways approaching navigation locks, trench intakes and so on. Because of the expansion of channel section, the main flow is separated from the boundary and forms a circulation flow near the cavity crest. In general, the velocity and turbulent intensity in the circulation flow are lower than that in the main flow, as a result, sediment drawn into the cavity basin is very likely to be deposited there. For instance, the de…     

DA白矮星视向速度测量

DA白矮星光谱在光学波段主要由巴尔默线主导,谱线比较宽,且谱线轮廓不对称,传统的线心方法确定视向速度非常困难。介绍了一种基于利用白矮星的有效温度(Teff)和表面重力加速度(log g)选择理论模板,通过交叉相关方法确定DA白矮星的APP速度,减去白矮星的引力红移得到白矮星的视向速度。测试发现对于有效温度高于10 000 K且信噪比大于20的DA白矮星的低分辨率光谱(R～2000),精度在10 km/s以内。基于这种方法测量了SDSS DR7的DA白矮星观测样本的视向速度,统计发现在1 000 pc内,视向速度的平均值接近于0。