查询词典 second boundary value problem

Based on varying process of generator terminal parameters after excitation fault, shortages of excitation protective principle of static stability boundary and asynchronous impedance boundary are analyzed. It proposed that excitation fault research relates to large-disturbance stability. Because dynamic power-angle character of generator after excitation fault is non-sinusoidal, there are differences between dynamic power-angle character and static state power-angle character. So it isn't ideal to protective operation result based on small-disturbance stability and static stability boundary criterion. At the same time, it proposed that asynchronous boundary impedance criterion is a constant reactive power circle moving adown j Xd′. It can ensure complete loss-of-excitation generator measuring impedance enter into the circle, but can't ensure the other condition measuring impedance including impossible losing synchronism enter. So loss-of-excitation protection would be maloperation when system voltage drops short and recovers or generator rejects load.③Based on stability principle, it puts forward setting conditions and calculation method of generator loss-of-excitation protection by direct measuring power-angle.

以励磁故障后发电机端的相关参数的变化为基础，通过对以静稳定边界和异步阻抗边界作判据的两类三种现行励磁保护在原理上存在的缺陷分析，发现：励磁故障是一个大干扰稳定性问题，励磁故障后的发电机的动态功角特性与静态功角特性有很大的差异，已远非正弦曲线，因此基于小干扰稳定性原理、以静稳定边界作判据的保护必然动作不理想；异步边界阻抗判据是一个下移j Xd′的等无功阻抗圆，它可以保证完全失磁后的发电机测量阻抗能进入该阻抗圆，但不能保证完全失磁之外的其它状态不会进入该阻抗圆，因此在系统电压短时下降或发电机突然甩负荷等情况下可能启动该保护使之误动。

The results show that the absorbing effect of low-order Higdon absorbing boundary condition is undesirable and relatively strong boundary reflection exists in wave field snapshot and analog recording; the effect of traditional and improved PML absorbing boundary conditions are similar, which can effectively absorb and attenuate the boundary reflections from any angle.

结果表明，低阶Higdon吸收边界条件吸收效果较差，在波场快照和模拟记录中存在较强的边界反射；改进的PML吸收边界条件与传统的PML吸收边界条件效果相当，均能有效地吸收衰减任意角度的边界反射波。

We have also presented the ω-circulant boundary condition and compared it with the helix boundary condition. Furthermore, we can also get another new boundary condition: the mixed boundary condition.

由此我们提出了ω循环型边界条件并将其与普通循环型及螺旋型边界条件作了分析和比较；进一步地，得到了一种新的边界条件：混合型边界条件。

In view of geological records preserved from different regions of the world are not identical, it's suggested that, when correlating the Ordovician-Silurian boundary, at the global boundary stratotype section, the FAD of N. persculptus be selected as the biomark, the transgression event identical to the FAD of N. persculptus as the auxiliary physical mark and the mass extinction and chemical anomaly events respectively as the auxiliary biomark and chemomark. In some regions with few graptolite, the Ordovician-Silurian boundary should be indicated by the auxiliary marks, such as the transgression event, mass extinction or chemical anomaly event, with the other fossil such as conodont nearest to other geological events as the provincial biomark for correlation. In other regions with much stratigraphic hiatus originated from the regression, the Ordovician-Silurian boundary should be marked by the regression-transgression event nearly relevant to the N. persculptus Zone.

鉴于不同地区留下的地质记录不完全相同，奥陶/志留系界线对比方法不同：在界线层型剖面上，以N.persculptus的首现为生物标志，以与之基本一致的海侵事件为辅助的物理标志，以生物集群绝灭事件和化学异常事件为辅助的生物和化学标志；在笔石极不发育的地区，则以海侵事件、生物绝灭事件或化学异常事件为辅助标志，以与其相距最近、并且具有区域对比性的其它门类化石作为界线对比的生物标志；对于由于海退事件所造成地层缺失很多的地区，则以海退/海侵事件作为划分界线的物理标志，并以相映的海侵事件的开始作为奥陶/志留系的分界。

The author compares the effects of Dirichlet boundary condition and attenuation one on artificial boundary with that on transmitting boundary, so does the absorption effects, the author also demonstrates the advantage of transmitting boundary.

文中还就刚性边界条件、衰减边界条件对人工边界的影响及吸收效果与透射边界作了对比，验证了透射边界的优越性。

Chapter 1 gives the background,current research process of relatedproblems and summarizes this thesis\'s work.In chapter 2,we study the Brownian motion with holding and jumping on the boundary.We use the resolvent method to obtain the infinitesimal generator because the domain of the infinitesimal generator is essentially the same as the range of the resolvent.Knowledge of this range and of the differential operator determines uniquely the infinitesimal generator.Since the semigroup generated by the DHJ is not strongly continuous,to use the nice property of strongly continuous semigroup in analytic theory,in chapter 3 we show that the dual is strongly continuous and derive ergodicity through spectral radius formulas and finally obtain the ergodic theorem by duality. In chapter 4,we discuss a class of a more general process---one dimensional Feller diffusion proposed by W.Feller in 1954.The Feller diffusion allows the possibility of jumps from boundary to boundary,not only from boundary to the interior.We give the stationary distribution of this process.

具体地，本文的结构如下：第一章给出了问题产生的背景，研究现状及本文的主要工作；第二章研究了在边界上逗留后随机跳的布朗运动，我(来源：3dABC论文网www.abclunwen.com)们用预解算子的方法得到其无穷小生成元，因为无穷小生成元的定义域本质上就是预解算子的值域，知道这个值域和微分算子形式就能唯一地决定无穷小生成元；由于DHJ过程产生的半群不是强连续的，为利用强连续半群的一些漂亮性质，在第三章中我们证明其对偶半群是强连续的，然后由谱半径公式得到遍历性并且最后由对偶得到遍历定理；第四章讨论了Feller在1954年引入的更广的一类过程----一维Feller扩散过程，Feller扩散过程允许有从边界到边界的跳发生，即不仅仅局限于从边界到内部的跳，在这一章中，我们给出了一维Feller扩散过程的平稳分布；在第五章，我们讨论了一些相关的问题，给出了DHJ过程对应的PDE问题及特征值与收敛速度的关系。

In viewof geological records preserved from different regions of the world are not identical, its suggested that, whencorrelating the Ordovician-Silurian boundary, at the global boundary stratotype section, the FAD of N.persculptus be selected as the biomark, the transgression event identical to the FAD of N. persculptus as theauxiliary physical mark and the mass extinction and chemical anomaly events respectively as the auxiliarybiomark and chemomark. In some regions with few graptolite, the Ordovician-Silurian boundary should beindicated by the auxiliary marks, such as the transgression event, mass extinction or chemical anomaly event,with the other fossil such as conodont nearest to other geological events as the provincial biomark forcorrelation. In other regions with much stratigraphic hiatus originated from the regression, theOrdovician-Silurian boundary should he marked by the regression-transgression event nearly relevant to the N.persculptus Zone.

鉴于不同地区留下的地质记录不完全相同，奥陶／志留系界线对比方法不同：在界线层型剖面上，以N.persculptus的首现为生物标志，以与之基本一致的海侵事件为辅助的物理标志，以生物集群绝灭事件和化学异常事件为辅助的生物和化学标志；在笔石极不发育的地区，则以海侵事件、生物绝灭事件或化学异常事件为辅助标志，以与其相距最近、并且具有区域对比性的其它门类化石作为界线对比的生物标志；对于由于海退事件所造成地层缺失很多的地区，则以海退／海侵事件作为划分界线的物理标志，并以相映的海侵事件的开始作为奥陶／志留系的分界。

The establishment principles of traditional and improved PML absorbing boundary condition were described. Through numerical simulation, the absorbing effect of improved and traditional PML absorbing boundary and low-order Higdon absorbing boundary on boundary reflection was discussed.

阐述了传统和改进的PML吸收边界条件的构建原理，通过数值模拟讨论了改进和传统的PML吸收边界以及低阶Higdon吸收边界对边界反射的吸收效果。

Sometimes the boundary and the boundary approximately equate, sometimes the boundary contains the ideal condition, but the boundary and the ideal condition not are a chapter of matter.

境与境界有时大致等同，境有时包含意境在内，但境界与意境并不就是一回事情。

Boundary polynomial point interpolation mesh-free method and boundary radial point interpolation mesh-free method were presented, based on polynomial basis and radial basis respectively for transient eddy current analysis, and their interpolation shape functions satisfy the Kronecker delta function and the essential boundary conditions can be directly imposed on the boundary nodes. An example on analyzing transient eddy current of a square metal column was set to prove the validity of the proposed methods, and a comparison on accuracy between BPPIM and BRPIM was analyzed as well.

运用多项式点插值法和径向基点插值法构造形函数，推导了适合于工程电磁场瞬态涡流问题的多项式基点插值边界无单元方法和径向基点播值边界无单元方法，这两种方法的空间插值形函数满足Kronecker delta条件，从而强加边界条件可以直接施加在边界点上，以金属长方柱的瞬态涡流分析作为数值算例，证实了两种方法的正确性和有效性，并对两种基类的点插值法进行了精度分析和比较。

Finally it offers the analysis of the fault-tolerance system as well as its test verification.

这样，运行于空间环境中的系统的设计目标就是在保证系统实时性

However, it is still difficult to find out the real reason of the increase of the keratinized gingiva during the orthodontic extrusion whether it is due to the proliferation of the gingival tissue or to its elastic nature, that is because the proliferation of the fibroblasts as well as the connective tissue changes in volume and the intra-fibers spaces were all immeasurable in most of the studies.

然而，仍然难以找到真正的原因增加的角化牙龈在正畸挤压它是否是由于扩散的牙龈组织或其弹性性质，这是因为增殖的成纤维细胞以及作为结缔组织的变化量和内部纤维空格都是不可估量的，大多数的研究。