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杜宁 《高等学校计算数学学报》2001,23(3):202-213
1 引 言关于二阶双曲型方程的有限元解的收敛性问题 ,目前已经有不少结果 .Dupont[1 ] 给出了一类线性双曲方程 Galerkin解的 L2 误差估计 ,Baker[2 ] 对此作了改进 ,用的是一种所谓“非标准的能量方法”.这一方法为 Cowsar,Dupont,Wheeler[3] 所采用 ,分析了一类具有吸收边界条件的线性双曲方程的混合元格式的 L2收敛性 .对于非线性双曲型问题 ,袁益让 ,王宏[4,5] 等给出了标准有限元方法的 H1 与 L2 误差估计 .本文试图把 [3]的工作更进一步研究 ,我们考虑如下非线性双曲问题 :φ(x) utt= mi,j=1 xi(aij(x) p(x,u) u xj) + mi=1… 相似文献
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神经传播方程的特征差分及特征有限元方法 总被引:2,自引:0,他引:2
给出矩形域上神经传播方程的两层特征差分及特征有限元格式,并且证明了l2和L2模误差估计是最优的. 相似文献
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为解决目前教学用落球法粘滞系数测定仪使用中出现的调节精度低、测量计算琐碎等诸多缺陷,我们改进了测定仪装置,通过增加光电传感器和光电计时器,使其更易于精准调节和测量,从而提高实验教学效率. 相似文献
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本文主要介绍了容灾的重要性和关键技术以及实现方法,在传统容灾架构的基础上分析了基于存储区域网络的现代容灾架构,并结合城域范围内的生产节点多样化和容灾需要多级化的特点,提出一种能够提供较佳性能的,基于城域容灾中心的容灾系统架构和实现方案。 相似文献
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为了减弱振动对车载激光雷达测量精度和稳定性的影响,借鉴浮筏减振系统在船舶领域的成功使用,对其进行了浮筏减振布局设计。采用多刚体动力学建模方法对系统在简谐激励下的减振性能进行了分析,得出系统各处减振器参量对系统减振效果的影响。根据选定的减振参量,结合所选车型,经过计算得到激光雷达主体的传递率峰值,有效避开了汽车运输过程中的激振频率,且几乎在有效的激振频率范围内传递率曲线都小于1;经计算得到冲击作用下的振动量程没有越过减震器的有效减震范围,符合理论要求;通过振动状态下激光雷达和探空气球所测风速数据的对比,验证了减振设计对保证测量精度的效果;通过静止和模拟振动状态下激光雷达的锁频效果对比,证明了浮法减振设计在车载系统中应用的可靠性。结果表明,浮筏减振设计应用于车载测风激光雷达是合理的、成功的。 相似文献
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The dissociation of H_2 molecule is the first step for chemical storage of hydrogen, and the energy barrier of the dissociation is the key factor to determine the kinetics of the regeneration of the storage material. In this paper, we investigate the hydrogen adsorption and dissociation on Mg-coated B_(12)C_6N_6. The B_(12)C_6N_6 is an electron deficient fullerene, and Mg atoms can be strongly bound to this cage by donating their valance electrons to the virtual 2p orbitals of carbon in the cluster. The preferred binding sites for Mg atoms are the B_2C_2 tetragonal rings. The positive charge quantity on the Mg atom is 1.50 when a single Mg atom is coated on a B_2C_2 ring. The stable dissociation products are determined and the dissociation processes are traced. Strong orbital interaction between the hydrogen and the cluster occurs in the process of dissociation, and H_2 molecule can be easily dissociated. We present four dissociation paths, and the lowest energy barrier is only 0.11 eV, which means that the dissociation can take place at ambient temperature. 相似文献
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For the three-dimensional convection-dominated problem of dynamics of fluids in porous media, the second order upwind finite difference fractional steps schemes applicable to parallel arithmetic are put forward. Fractional steps techniques are needed to convert a multi-dimensional problem into a series of successive one-dimensional problems. Some techniques, such as calculus of variations, energy method, multiplicative commutation rule of difference operators, decomposition of high order difference operators, and the theory of prior estimates are adopted. Optimal order estimates are derived to determine the error in the second order approximate solution. These methods have already been applied to the numerical simulation of migration-accumulation of oil resources and predicting the consequences of seawater intrusion and protection projects. 相似文献
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