查询词典 diffusion equation

Waxman-Smits equation is an evolution of Acrhie equation for shaly sands, and it is a nonlinear equation.

Waxman-Smits方程是阿尔奇方程在泥质砂岩地层中的推广，W-S方程为非线性方程。

In this paper,by using the idea of F-expansion method (where F is a known solution of an ordinary differential equation with fourth positive power nonlinearity),the problem of seeking the exact solutions of the generalized BBM equation with any positive power nonlinearity is changed into seeking the exact solutions of an ordinary differential equation with fourth positive power nonlinearity.

利用F-展开法的思想(F是一阶四次常微分方程的一个解)，将求含有任意次正幂项非线性广义BBM方程的精确解转化为求一阶四次常微分方程的精确解。

More than 80％ of the root system was at this layer. The vertical distribution of root weight and root volume could be expressed by exponential equation, power equation or polynomial equation.

各品种水稻根系重量均随土层深度增加而下降，但主要分布在土壤耕作层（0-20cm），而表层（0-10cm）就占80％以上。

In the last chap-ter,the natural integral equation and natural boundary element method forharmonic problem on exterior elliptic domain are introduced.Then,based onthis,the natural boundary reduction method for a kind of exterior problem ofanisotropic constant coefficients elliptic equation is discussed, the natural inte-gral equation and its solving method on circular boundary and elliptic bound-ary are obtained.These results can be directly applied in coupled methodand DDM for exterior boundary value problem.

最后，讨论了椭圆外区域调和问题的自然积分算子即D-N算子及自然边界元方法，并基于此研究了一类各向异性常系数椭圆型方程外问题的自然边界归化方法，首次得到其在圆周边界及椭圆边界上的自然积分方程及其求解方法，并将这些结果直接应用于外边值问题的耦合算法。

The main contents of this course include: the construction, convergence, compatibility and stability of finite difference scheme of elliptic equation, parabolic equation and hyperbolic equation, the construction method and computation format of finite difference scheme of a system of partial differential equations.

本课程主要内容有：椭圆型方程的有限差分格式的构造，有限差分格式的收敛性，相容性及稳定性、抛物型方程的有限差分格式的构造，有限差分格式的收敛性，相容性及稳定性、双曲型方程的有限差分格式的构造，有限差分格式的收敛性，相容性及稳定性、偏微分方程组的有限差分格式的构造方法及有关的计算格式。

Firstly, the author establish the functions of stability on the basis of the spline function method ,according to the theory of geometrical nonlinear and the theory of stability, educe the stability equation of structure based on variational principle, then carry through the flexuosity analysis of CFST arch.The big distortion geometrical nonlinear was considered by the stability equation,the author simplified the problem of geometrical nonlinear through ignored quadratic term and reserve the simple term, at last boiled down to solve the linear stability equation of eigenvalue .

利用样条函数方法、根据几何非线性变形理论和结构稳定性理论，先建立起结构稳定的泛函，再由变分原理导出结构的稳定方程，进行钢管混凝土拱屈曲分析；本文所建立的稳定方程考虑了几何非线性的大变形效应，通过忽略几何非线性的二次项，保留一次项，将几何非线性问题简化，最后归结为求解线性稳定问题的特征值稳定方程，建立了结构非线性静力稳定性问题的新算法及失稳类型判别准则。

According the connection between the solution of linear fractional differential equation and nonlinear fractional differential equation, the expression of the solution of the nonlinear fractional differential equation is formed.

在一定的条件下，建立了非线性分数阶微分方程在边值条件下有解存在。

The equation is a Fredholm integral equation of the first kind which is extremely unstable. The solution of this equation is the brightness temperature of target.

本文建立天线模型得到天线温度方程，它是病态的第一类Fredholm积分方程，求解目标亮度温度也即求解这个积分方程。

In this paper the direct boundary integral equation of two-dimensional Laplace equation for Dirichlet problem is considered, which is deduced by Green's formula and the fundamental solution, and is a Fredholm integral equation of the first kind.

本文考虑用Green 公式和基本解推导得出直接边界积分方程来求解二维Laplace 方程的Dirichlet 问题，该直接边界积分方程是第一类Fredholm 积分方程。

Using Biot's 2D elastodynamic theory solves the saturated soil equation. The Fredholm integral equation of the second kind can be built by using the fundamental solution of circular load, the compatibility condition and superposition method. The Fredholm integral equation of the second kind of pile groups can be solved by using numerical method. The numerical solutions of pile groups axial forces, pore pressures under vertical harmonic loading and shear forces, moments and pore pressures under horizontal harmonic loading can be obtained.

采用Biot提出的三维波动原理，利用圆形简谐载荷作用下的Biot固结方程的基本解和桩土之间的变形协调条件，并采用叠加原理得到饱和土中群桩的第二类Fredholm积分方程，应用数值法求解群桩的第二类Fredholm积分方程，得到在垂直简谐载荷作用下群桩的轴力、孔压随桩身变化的数值结果以及在水平简谐载荷作用下群桩的剪力、弯矩和孔压随桩身变化的数值结果。

The changes of the HAF after liver injury may be related to the volume of blood loss, the intraabdominal pressure and the pneumoperitoneum duration.

肝撞击伤伴失血后肝动脉血流量的变化与失血量、气腹压力以及气腹持续时间等有密切联系。

Reneging on our commitments to the world's poor cannot be an austerity measure, she said.

放弃我们给世界上的穷国的承诺不能成为一种紧缩措施。