边界

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。

Second order incident boundary condition on fixed incident boundary is derived for numerical simulations, based on the cnoidal or sinusoidal motions of wave maker paddle, which shows that the prediction with second order incident boundary condition is more accurate than the prediction with first order incident boundary condition. 2 The analytical solution for higher-order Boussinesq equations is derived and its applicable range is discussed. 3 A 2-D fully non-linear numerical model using boundary element method is developed to obtain wave forces acting on rectangular obstacle. 4 The three-dimensional fully non-linear waves are studied in a numerical wave tank using finite element method.The studies on the coupled numerical model combined Boussinesq equations with Laplace equation are following.

非耦合非线性波浪计算模型：1 根据造波板做椭圆余弦运动或正弦运动速度，推导出数值模拟波浪水槽时固定入射边界上的二阶波浪入射边界条件，数值计算结果和实验结果的对比表明采用二阶入射边界条件对波面升高的预报比采用一阶入射边界条件对波面升高的预报更为精确；2 推导了波浪水槽造波板做正弦运动所产生波浪的高阶Boussinesq方程摄动展开解析解，讨论了该解析解的适用范围；3 对整个波浪水槽应用边界元方法数值模拟了波浪对物体的非线性作用；4 用有限元法求解三维Laplace方程模拟了三维完全非线性波浪水槽。

The research achievement are acquired as follows: 1From mathematical models for inverse scattering in two dimensional homogenous media including Dirichlet, Neumann, Robin,all kinds of probable mixed boundaries and cracks, direct and inverse scattering are discussed, and ill-posed integral equation and indicator function method are formulated for the diverse of boundary identification. It is shown that the kernel of the integral equation characters the boundary of scatterer, which is determined by solving it by virtual of regularity method, meanwhile, some numerical tests are given.

本研究取得了如下研究成果： 1）在二维均匀介质逆散射各种边界识别的数学模型（包括Dirichlet，Neumann，Robin，各种可能的混合边界问题，裂纹问题）下，分别考虑了正散射问题和逆散射问题，推导了上述各种边界识别的不适定积分方程以及指示函数方法，由于积分方程的核充分表征了散射物的边界，由此说明只要利用正则化方法求解该积分方程，就可以确定散射物的边界，并给出了一些数值实验。

Aimed at increasing the accuracy and speed of BEM, meanwhile decreasing taken up memory, this dissertation has studied singular integrals and nearly singular integrals of BEM, surface BEM character and multipole BEM delaminating and storing technology, and put forward high precision fast BEM. And appling this method the electric potential and electric field intensities distribution of the UHV insulators are calculated preliminarily.

本论文以提高边界元的精度和计算速度，降低计算机内存占用为目标，研究了边界元的奇异积分和接近奇异积分计算方法、曲面边界元特性以及多极子边界元分层和存储技术，提出了高精度快速边界元法，并运用该方法初步计算了特高压绝缘子上电位和电场强度分布。

Aimed at increasing the accuracy and speed of BEM , meanwhile decreasing taken up memory, this dissertation has studied singular integrals and nearly singular integrals of BEM , surface BEM character and multipole BEM delaminating .

本论文以提高边界元的精度和计算速度，降低计算机内存占用为目标，研究了边界元的奇异积分和接近奇异积分计算方法、曲面边界元特性以及多极子边界元分层和存储技术，提出了高精度快速边界元法，并运用该方法初步计算了特高压绝缘子上电位和电场强度分布。

From a uncertain point which located outside of the figure to draw radial, according to the junction of radial and polygon to judge the internal and outside relationship; Boundary algebra filling, a vector convert to raster arithmetic which based on integral thought, suit for polygon vector convert which

录拓扑关系的多边形矢量数据转换，方法是由多边形边界上某点开始，顺时针搜索边界线，上行时边界左侧具有相同行坐标的栅格减去某值，下行时边界左侧所有栅格点加上该值，边界搜索完毕之后即完成多边形的转换。关系，并表示成矢量格式边界线的过程。步骤包括：多边形边界提取，即使用高通滤波将栅格图像二值化；边界线追踪，即对每个弧段由一个节点向另一个节点搜索；拓扑关系生成和去处多余点及曲线圆滑。

A new concept of administrative boundary is put forward, and it is argued that the administrative system reform in China should be first of all performed as the restructuring of admi...

以行政边界和行政组织边界&两重边界的重构&为理论基础，提出我国行政体制改革首先在宏观上表现为行政边界的重构，其次在中观层面上要求行政组织边界作出相应的调整，以解决行政组织结构对行政效率的制约。

Compared with the conventional analytic methods, the author studies the feasibility that the elastic bearing model is used to simulate the boundary constraint condition of the enrockment.

引入弹性边界模型，对比传统分析中对边界约束的处理，研究用弹性边界来模拟堆石体边界约束条件的可行性；选用规则典型的坝体，研究面板堆石坝的面板及堆石体的应力应变规律，特别是周边缝的变形规律；分别讨论了岸坡坡比、坝前水深、坝高、河床底宽等几何参数对弹簧系数取值的影响，确定弹簧系数的取值范围，给出了可用于实际工程计算的最佳取值范围；以松山面板堆石坝作为工程实例，验证弹性边界模型的实用性，并为工程建设提供了一定的参考。

Then it gives a border tracking method using two edge operators to track the border of feature area.

提出了一个在二维数据场中进行特征边界跟踪的方法，采用2个边界算子抽取边界，用树形结构表示特征边界之间的关系，用Fourier描述器描述特征边界并重构。

The two-dimensional transient finite element analysis and thermal responsecalculation were carried out for prestressed concrete box girder with irregular crosssection. Various boundary conditions were discussed in detail.

在有限单元分析中，首次推导出混合边界单元的计算公式，从而将第二类边界条件和第三类边界条件统一起来，以第三类边界条件的形式施加到单元边界上。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。