Background current affects the internal wave structure of the northern South China Sea

The internal wave modal equations are solved with the consideration of background currents. Analytical and numerical solutions of some specific examples, including observations in the northern South China Sea (SCS), are obtained to investigate the effect of background current on internal wave vertical structure. The effects of current shear and curvature on internal wave vertical structure are evaluated separately. It is found that the phase speed and wave structure are modified by background currents, the current shear has little effect on wave structure, whilst the current curvature could have strong impact on wave structure. The extent of the effect by the current curvature on the wave structure depends on the magnitudes of current curvature, relative wave speed, and buoyancy frequency, sometimes the effect by the current curvature may even cause the wave to attenuate severely with depth. A new method to obtain the real eigenfunction with depth in the case that the waves become evanescent is also put forward. It is shown that, the residual tidal current in the northern SCS is strong enough to cause the wave to attenuate severely at upper layer.     

面向大数据应用的多层次混合式并行方法

基于很多大数据应用存在对数据进行多种并行处理的需求, 提出两层混合式并行方法, 即执行单元的混合并行和计算模型的混合并行. 通过在同一个计算节点上执行单元的混合并行, 充分挖掘基础设施的计算能力, 从而提高数据处理性能; 采用在同一个执行引擎中集成多个计算模型的并行方法, 以适合应用多样异质处理模式. 不同的混合并行方法可以契合不同的数据和计算特点, 以满足不同的并行目标. 介绍了混合式并行方法的基本思想, 并以前期开发的并行编程模型BSPCloud为基础, 阐述了进程和线程混合并行、BSP和MapReduce混合并行的主要实现机制.     

Cr元素掺杂碳化硅导致铁磁性的第一性原理研究

基于第一性原理研究了Cr元素掺杂3C-SiC的电子结构和磁性,揭示了Cr元素掺杂3C-SiC的磁矩形成以及铁磁耦合的微观物理机制,发现同时引入N元素后Cr元素掺杂3C-SiC的形成能大幅降低,并对其形成能降低的机理进行了系统的讨论,给出了合理的解释,在过渡金属掺杂时引入N元素能够显著地降低磁性杂质的形成能。     

Muller矩阵用于光栅单色仪的偏振效应分析

本文给出一种利用Muller矩阵分析光学系统偏振响应的实用方法，并以WDG30型光栅单色仪为例，详细讨论了Muller矩阵的测量步骤，给出了误差消除方法，提高了测量精度。