A parallel two-level method for simulating blood flows in branching arteries with the resistive boundary condition

Computer modeling of blood flows in the arteries is an important and very challenging problem. In order to understand, computationally, the sophisticated hemodynamics in the arteries, it is essential to couple the fluid flow and the elastic wall structure effectively and specify physiologically realistic boundary conditions. The computation is expensive and the parallel scalability of the solution algorithm is a key issue of the simulation. In this paper, we introduce and study a parallel two-level Newton–Krylov–Schwarz method for simulating blood flows in compliant branching arteries by using a fully coupled system of linear elasticity equation and incompressible Navier–Stokes equations with the resistive boundary condition. We first focus on the accuracy of the resistive boundary condition by comparing it with the standard pressure type boundary condition. We then show the parallel scalability results of the two-level approach obtained on a supercomputer with a large number of processors and on problems with millions of unknowns.     

有限差分法和隐式龙格库塔法求解Burgers方程

提出一个新的方法求解一维Burgers方程,组合使用有限差分法和隐式龙格库塔法求解Burgers方程。首先使用二阶有限差分法进行空间离散,得到一个常微分方程组,然后使用高阶A稳定的隐式龙格库塔法求解常微分方程组,最后比较数值解和精确解,数值结果证实该方法有很高的精度和稳定性。     

"应用语言学"与"语用学"术语辨析

本文论述了语用学、应用语言学和语言的应用三个术语的产生以及内涵与外延的发展演变情况和它们之间的关系。在参考各家观点的基础上,对三者之间的联系与区别进行了全面、详细的辨析。全文共分四部分:语言的应用“与应用语言学“”;应用语言学”的内涵与外延“;语用学”“与应用语言学”;有“关语用”研究论文的调查。     

Modeling and simulation for a drop-impact analysis of multi-layered printed circuit boards

Multi-layered printed circuit boards (PCBs) contain a multi-layered structure that is suitable for high-speed and high-frequency applications. Hence, they are used extensively in electronic packaging assemblies for high-density applications. However, numerous composite parts and complex material properties of multi-layer PCBs complicate the reliability simulation of PCB model. This paper deals with a finite element analysis intended to describe numerically the behavior of multi-layered multi-materials PCB model (combination of metallic and composite plies) in the drop-impact performance. Through the comparison of physical drop test results, the fully multi-layered model illustrates higher accuracy if compared with that of the traditional simplified isotropic model and orthotropic model. The effects of material properties for the multi-layer PCB under drop-impact shock have also been investigated.     

大亚湾核电站实施18个月换料的放射性后果评估

针对大亚湾核电站实施18个月换料技术改造的特点，计算了大亚湾核电站在正常运行工况下以及各种设计基准事故工况下对周围环境的放射性后果。计算结果表明，大亚湾核电站实施18个月换料技术改造后，正常运行工况安全设施的性能满足GB6249－86的要求。     

材料成形过程模拟技术及其应用

综述了目前材料成形工程模拟的状况，介绍了塑料注射成形、金属铸造成形和板料冲压成形模拟的功能和特色，着重分析了这三种成形过程模拟的关键技术和创新点，并通过实例验证和大范围的推广应用，实现了材料成形过程模拟软件的实用化和商品化。     

Downlink CoMP Resource Allocation Based on Limited Backhaul Capacity

Coordinated Multi-Point(CoMP) transmission is put forward in the Long Term Evolution-Advanced(LTE-A) system to improve both average and cell-edge throughput. In this paper, downlink CoMP(DL-CoMP) resource allocation scheme based on limited backhaul capacity is designed to take a tradeoff between system throughput and fairness. Resource allocation of proportional fairness based on querying table is proposed. It updates RB allocation matrix when center cell has completed resource allocation and delivers the matrix to adjacent cells for their own RB allocation. Furthermore, Water-Filling algorithm based on adaptive water level(AWF) is used for power allocation to boost system fairness. In this paper, performance of downlink CoMP based on limited backhaul capacity and single-point transmission is contrasted, and results indicate that CoMP dramatically enhances system throughput and spectral efficiency. Moreover, AWF power allocation scheme obtains higher system fairness than conventional Water-Filling(WF) algorithm, although it gets slightly lower system throughput. Finally, this paper discussed that the system performance is partially affected by the percentage of CoMP resource.     

稳流罐筒体内壁堆焊工艺

稳流罐是用于核泵全流量试验台的重要组件,属于3类压力容器,在整个平台中起到平衡流量的作用.筒体钢板材质为13MnNiMoR,简体内壁全部采用E309L+E316L不锈钢堆焊,我公司之前没有13MnNiMoR钢板堆焊经验,本文详细介绍了13MnNiMoR钢板采用E309L+ E316L堆焊的工艺制定思路和试验结果.     

新型辊底式轴承套圈热处理生产线

针对现有几种套圈热处理设备存在的不足,开发了一种新型辊底式轴承套圈热处理生产线,介绍了其布局、工作过程及结构特点。     

轴向磁通空气心永磁同步发电机的谐波抑制

通过改善永磁体形状为正弦形,优化轴向磁通空气心永磁同步发电机的电动势波形。利用解析法计算正弦形永磁体的轴向磁密分布。通过有限元软件分析、比较了不同极弧系数情况下正弦形永磁体结构电机的磁密分布和电动势波形。最终得出结论:对于正弦形永磁体,随着极弧系数的增大,电机气隙磁密波形以及电动势波形的总谐波失真度逐渐减小,波形更加趋近正弦波形。