查询词典 boundary element method

So, in this paper, a circular cavity witha large radius is used to replace the straight boundary of thehalf space, then the half space problem can be changed tothe scattering problem of two circular cavities to the steadyincident P-wave . Having the aid of the mature cylinderfunction theory, the general solutions of the wave functionscan be given, and an infinite linear algebraic equations ofthe unknown coefficients in the wave functions can be gottenwith the boundary conditions and the Fourier complex seriesexpansion technology, the infinite linear algebraic equationscan be approximately solved by the finite trunction withsatisfying some definite precision, at the basis of thissolution of the equation, the variations and the lay-outs ofthe DSCF at the circular cavity boundary vs. the differentincident angles, the different embedded depths of thecircular cavity as well as the different dimensionless wavenumber of the incident P-wave.

为此，本文采用一个半径很大的圆孔来代替半空间的直边界，将该半空间问题转化为一无限大空间中两个圆孔对稳态P波的共同散射问题，借助于成熟的柱函数理论，通过写出问题波函数的一般形式解，利用问题的边界条件，并采用复数傅立叶级数展开技术将其化为一个仅包含问题波函数中未知系数的一无穷线性代数方程组，在满足一定计算精度的前提下，通过有限项截断进行近似求解，进而讨论了圆孔边界处的动应力集中系数随不同入射角、不同的圆孔掩埋深度、入射波的不同无量纲波数以及介质的泊松比变化和分布情况。

In this project, we study the theory of higher order differential equations in Banach spaces and related topics. We solve an open problem put forward by two American Mathematicians and two Italian Mathematicians concerning wave equations with generalized Weztzell boundary conditions, introduce an existence family of operators from a Banach space $Y$ to $X$ for the Cauchy problem for higher order differential equations in a Banach space $X$, establish a sufficient and necessary condition ensuring $ACP_n$ possesses an exponentially bounded existence family, as well as some basic results in a quite general setting about the existence and continuous dependence on initial data of the solutions of $ACP_n$ and $IACP_n$. We set up quite a few multiplicative and additive perturbation theorems for existence families governing a wide class of higher order differential equations, regularized cosine operator families, regularized semigroups, and solution operators of Volterra integral equations, obtain classical and strict solutions having optimal regularity for the inhomogeneous nonautonomous heat equations with generalized Wentzell boundary conditions, gain novel existence and uniqueness theorems,which extend essentially the existing results, for mild and classical solutions of nonlocal Cauchy problems for semilinear evolution equations, present a new theorem with regard to the boundary feedback stabilization of a hybrid system composed of a viscoelastic thin plate with one part of its edge clamped and the rest-free part attached to a visocelastic rigid body. Also we obtain many other research results.

在本研究中，我们对Banach空间中的高阶算子微分方程的理论以及相关理论进行了深入研究，解决了由美国和意大利的四位数学家联合提出的一个关于广义Wentzell边界条件下的波动方程适定性的公开问题，恰当地定义了Banach空间中的高阶算子微分方程Cauchy问题的算子存在族及唯一族，建立了齐次和非齐次高阶算子微分方程Cauchy问题适定性的判别定理，获得了关于高阶退化算子微分方程的算子存在族、正则余弦算子族、正则算子半群、Volterra积分方程解算子族的乘积扰动和混合扰动定理，得到了关于以依赖于时间的二阶微分算子为系数的一大类非自治热方程非齐次情形下的时变广义Wentzell动力边值问题的古典解、严格解的最大正则性结果，获得了半线性发展方程非局部Cauchy问题广义解和经典解存在唯一的判别条件，从实质上推广了现有的相关结果；得到了一部分边缘固定而另一部分附在一粘弹性刚体上的薄板构成的混合粘弹性系统的边界反馈稳定化的新稳定化定理，还建立了一系列其他研究结果。

In the initial stage, the convergence of the low layer was stronger than that of the upper layer of the boundary layer, and the rotation of the boundary layer flow was weak, so a convergence line of the boundary layer was one of important factors to trigger convection.

MCS初期边界层低层的辐合强于边界层高层辐合，边界层气流旋转作用较弱，边界层辐合线是对流触发的重要因素之一。

Based on the classical Ekman theory, a series of intermediate Ekman boundary layer models, which retain the nonlinear advective process while discard embellishments, have been developed with the intention to understand the complex nonlinear features of the Ekman boundary layer and its interaction with the free atmosphere. In this paper, the recent advances in the intermediate boundary-layer theoretical models are reviewed.

摘要大气边界层及其与自由大气之间的相互作用具有明显的非线性特征，而这些特征是经典Ekman理论所不能描述的，因此，发展中等复杂程度（介于完全模式与经典Ekman模型之间）的大气边界层动力学模式，简称中间模式，对人们从理论上认识大气边界层动力学过程的非线性特征具有重要意义。

This paper addresses a new boundary detection algorithm called BORAL (Boundary Points Detector Based on Angle),according to the problem of low efficient boundary detection and that it is uneasy to determine the scope of the parameter pruning in data mining.

针对目前数据挖掘中边界点检测效率低、参数阈值范围不容易确定的问题，提出一种新的边界点检测算法BORAL。

The biomarkers such as the n-Alkanes, the isoprenoids, the terpane, and cholestane were detected through GC-MS analysis. Based on the study of the biomarkers, the biological evolution during Permian and Triassic can be divided as three stages, namely, the mixing source stage of low biota such as thallose and advanced plant in late Permian (below bed 63), the stage of low biota such as thallose in the boundary transitional layer (bed 63-69) and the mixing source stage of advanced plant and low biota such as thallose in early Triassic (above bed 69). What's more, the second stage near the boundary transitional layer can be subdivided into 4 stages. The stages of biota evolution is close related with sedimentary environment changing and the boundary transitional layer.

利用GC—MS分析技术，在陆相地层中检测出正构烷烃、类异戊二烯烷烃、萜烷和甾烷类生物标志化合物并根据生物标志化合物和特征值研究，将二叠系—三叠系生物演化划分为三个大的阶段，即晚二叠世的菌藻类低等生物与高等植物混源阶段（63层以下），界线异常层的菌藻类低等生物阶段（63-69层）和早三叠世高等植物与菌藻类低等生物混源阶段（69层以上），界线附近异常层的第二阶段又进一步细分为4个次一级阶段，生物演化阶段与沉积环境变化及界线异常层具有非常密切关系。

However, such tidal overheight is often ignored in the current regional numerical simulation due to intensive computational requirement. Only the mean sea level is used as the fixed seaward boundary, which may wrongly predict the groundwater table position. Therefore, we aim to determine an equivalent seaward boundary through numerical modeling. The equivalent seaward boundary takes into account the tide-induced overheight effects.

然而，由于潮汐动边界处理的复杂性而导致巨大的计算量，在现有的区域地下水数学模型中，潮汐引起的海平面波动通常被忽略，仅仅以平均海平面高度作为模型的海岸边界条件，其预测出的地下水水位位置与实际情况可能会有一定的误差。

A simplified model was proposed to simulate material microstructure according that metal solidification is a Monte Carlo process. First, use the point of"putting randomly, growing uniformly"to generate grain boundary, then recognize grain boundary trifurcate points, eliminate bad trifurcate points, and distinguish the connections among these points, thus obtain straight grain boundary picture.

根据金属凝固过程是—Monte Carlo过程，建立了金属材料显微组织的简化Monte Carlo方法，采用&随机投放，等速生长&的方法形成矩齿形晶界图，并通过逐点判断法识别出晶界三重点，剔除奇异三重点，并识别出晶界及晶界间相邻关系，从而获得晶界结构的直线近似形态图，为细观组织短裂纹的数值模拟作好准备。

With that point in mind we review here some advances in the classical boundary layer, multilayer boundary layer, interacting boundary layer and diffusion parabolized NS equations theories and corresponding algorithms and applications.

以此为线索，简要评述经典边界层、多层边界层、干扰边界层、扩散抛物化 NS方程诸理论、相应算法和应用的若干研究进展；诸理论之间以及他们与实验的关系；简化湍流计算的一点注释以及物理分析和数值模拟相结合的一些问题。

The results show that the relationship betweentotal potential energy and time step exhibits periodic characteristic when sigma-3symmetric twist grain boundary model and sigma-3 tilt grain boundary model slide atOK. But for sigma-13 asymmetric tilt grain boundary, the relationship between totalpotential energy and time step exhibits damp surge characteristic.

结果发现，∑3对称扭转晶界模型与∑3对称倾侧晶界模型在0K滑动时，系统的势能与计算步数之间的关系曲线呈现周期性变化的规律，而∑13非对称倾侧晶界模型系统的势能与计算步数之间的关系却呈现阻尼振荡特征的变化规律。

I hope that this success is just the first in a long series.

我希望这只是成功的开始。

Three dimensional stresses on the interface of tire and soil, tire deflection and soil sinkage are measured.

测试轮胎——沙土界面上的三向应力、轮胎变形和沙土沉陷；建立考虑剪切应力对沙土承载特性产生影响的车轮牵引性能预测模型；分析车轮作用下土壤的纵向稳定性。