Finite element computations of two-dimensional arterial flow in the presence of a transverse magnetic field

A finite element solution of the Navier-Stokes equations for steady flow under the magnetic effect through a double-branched two-dimensional section of a three-dimensional model of the canine aorta is discussed. The numerical scheme involves transforming the physical co-ordinates to a curvilinear boundary-fitted co-ordinate system. The shear stress at the wall is calculated for a Reynolds number of 1000 with the branch-to-main aortic flow rate ratio as a parameter. The results are compared with earlier works involving experimental data and found to be in reasonable qualitative agreement. The steady flow, shear stress and branch flow under the effect of a magnetic field have been discussed in detail.     

开关型磁阻电动机的振动分析

针对SR电动机存在的振动和噪声问题,分别应用实验模态分析法和计算模态分析法研究了SR电动机的动力特性,得到了SR电动机定子的固有频率和主振型,计算值与实验测量值吻合较好,所得数据可为制定抑制SR电动机的振动和噪声方案提供参考.     

邮政通信网局部预测模型的研究和实现

为建立模型对网络实体流量流向进行预测,通过对实际情况的分析,得出新的局部预测模型方案,并为模型设定多级子模型,当模型需要变换时,只需要加入新的影响因素,不需要改变模型框架,这样使得模型更加适合邮政通信网仿真优化的需要。对于其它类似的仿真系统模型建立也有一定的启发作用。     

贵县式三水铝土矿微量元素地球化学特征及其意义

本文应用微量元素地球化学理论,通过研究区内地层、红土剖面及矿物相中微量元素含量分配特点,结合野外观察结果,得出了本区三水铝土矿的成矿源岩是郁江组地层的结论,为本区找矿提供了新的线索。     

A RAPID APPROXIMATION FOR PREDICTING THE HYDROCARBON DISCOVERY RATE: PART 1. ASSESSING THE ACCURACY

The hydrocarbon discovery prediction problem is important to firms having to make decisions about the deployment of scarce exploration resources. Traditional methods for estimating the discovery rate rely on the completion of time consuming simulation experiments. A rapid approximation that does not require the completion of simulation exists and has been shown to have some promise as a prediction tool. This paper investigates the accuracy of the approximation method under a wide variety of distributional and drilling efficiency assumptions. The results indicate that the approximation produces predictions close to those of simulation under most of the tested conditions. This suggests that resource exploration firms could conveniently use the method for a wide variety of planning purposes without incurring the same costs in time and personnel required for simulation.     

一种可行的智能三维特观设计系统的设计方法

针对复杂地区地震勘探的三维观测系统设计这一困扰广大地震勘探科技人员的难题，进行了较为全面细致的分析和论述，文章从与三维地震勘探的成本和效益方面密切相关的覆盖次数问题，激发点冗余浪费问题，以及特管勘探设计与常规勘探设计的关系问题入手，进行了深入的探讨，并给出了一种解决该问题的计算机交互式实现方法，对于三维地震勘探具有指导价值。     

Superconvergence of discontinuous Galerkin finite element method for the stationary Navier‐Stokes equations

This article focuses on discontinuous Galerkin method for the two‐ or three‐dimensional stationary incompressible Navier‐Stokes equations. The velocity field is approximated by discontinuous locally solenoidal finite element, and the pressure is approximated by the standard conforming finite element. Then, superconvergence of nonconforming finite element approximations is applied by using least‐squares surface fitting for the stationary Navier‐Stokes equations. The method ameliorates the two noticeable disadvantages about the given finite element pair. Finally, the superconvergence result is provided under some regular assumptions. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 23: 421–436, 2007     

Assessment of thermal expansion coefficient of methylsilsesquioxane thin film

For the methylsilsesquioxane film whose optical birefringence is almost zero, it was recently reported that its vertical thermal expansion coefficient (CTE) was approximately one order of magnitude larger than the lateral CTE. Though the birefringence is not an absolute predictor of anisotropic behavior, the discrepancy in both the CTEs was so remarkable that it was essential to investigate whether the anisotropy was intrinsic property or not. If the effect of Poisson's ratio is considered in the calculation of the vertical CTE and when elastic modulus measured by surface acoustic wave spectroscopy is used in the assessment of the lateral CTE, both the CTEs are coincident with each other. Therefore, it can be concluded that the discrepancy in the CTEs can be attributed to a higher in‐plane polymer chain orientation but it can also arise from the misleadingly assumed modulus and Poisson's ratio. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3109–3120, 2006     

The Extraction Method of Cutting Engagement in Ball-end Milling Simulation

Ball-end mill is widely used in workpiece processi ng with free-form surfaces. Such models that can predict processing character istics precisely are very necessary to the aim of cost reducing, quality improvi ng and productivity progressing, the cutting force prediction is the most import ant among these models. To explore the physical essence of metal cutting, model researchers commonly simplify the geometric conditions in cutting process, and a ssume that the geometric parameters that are needed to s...     

利用单元状态的改变模拟采场破坏规律

采用能较好反映混凝土等脆性材料破坏特征的五参数Wilianm-Warnke强度准则破坏模型，利用有限单元法单元“处死”的功能模拟回采过程和相似材料模拟试验研究，初步总结出缓倾斜厚煤层悬移支架放顶煤顶板活动及矿压显现规律，为缓倾斜厚煤层悬移支架放顶煤制定较为合理的方案、安全技术措施等提供重要的依据和指导作用。