条件方程

We deal with the biharmonic equation and proved that under our assumptions, the week solution of the natural boundary value problem strongly converges (in H~2) to that of the first boundary value problem.

为克服这一困难，我们用具自然边界条件的边值问题(在二阶椭圆型方程情形为第三边值问题)去逼近相应的第一边值问题，并以重调和方程为例，证明了在一定条件下，其具自然边界条件的边值问题的弱解在H~2的意义下强收敛到相应的第一边值问题的弱解。

In this paper, we will discuss the existing condition of the periodic solution of Duffing type equation with damping term. We use homeomorphism and fixed point method to prove the periodic solutions existence. We try to loose its condition, analysis and then get the existing condition of periodic solution according to defining atmospheric dynamics equation.

本文中，我们探讨带阻尼项的Duffing型方程周期解的存在性条件，运用不动点方法和Leray-Schauder度理论来证明其存在周期解，尽可能放宽其约束条件，并针对具体的大气动力学方程，分析并求取其周期解的存在性条件。

To research the propagation characteristics of travelling wave along transmission line in depth, the authors establish a mathematical model of travelling wave along lossless transmission line with the format of discrete time and space mesh lines, derive the stable condition and boundary condition of the wave equations using numerical solution of partial differential equation, and attempt the simplification of the boundary condition to realize full decoupling of voltage and current.

为深入研究行波在配电线路上的传播特性，建立了时间-空间网格线离散格式的无损传输线行波数学模型，采用偏微分方程的数值解法推导了波动方程的稳定条件和边界条件，并尝试对边界条件进行简化，以实现电压和电流的完全解耦。

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。

Later, we estimate our variational functional to get a nontrivial solution of the new equation and so the second solution for is obtained.

然后我们利用函数平移将原来的非齐次边界问题转化为奇次边界问题，验证了其对应的变分泛函满足不带条件的山路引理的两个条件，并给出了泛函临界点存在的一个充分条件，最后对具体的变分泛函进行估计，得到了新方程非平凡解的存在性结果，从而得到了原方程第二个正解的存在性结果。

The main contents include the ray phenomenon and its generation conditions; the deduction and physical illumination of wave action conservation equation and wave number conservation equation; ray theory for sinusoidal waves; Fermat's principle; the variation of amplitude in the case of straight and parallel depth contours and circular depth contours; the amplitude near the caustics; wave trapping; deduction of mild-slope equation and the relevant numerical solution methods.

讲授折射现象及其发生的条件；波作用守恒方程和波数守恒方程的推导及物理解释；稳恒正弦波的控制方程及射线方程；费马原理；利用射线方程研究等深线是平行直线和圆周线时波振幅的变化，特别是焦散线附近波高的变化以及由此而产生的波的俘获；缓坡方程的推导及有关的数值求解方法。

The weak formulation permit is satisfied not point by point, finite element method balances only at node neighborhood, in unit balance is not required, in analytical method single check from infinite series does not satisfy the equation, but infinite number of points satisfy the equation, and then the weak formulation of dual system of Hamilton equations was educed.

基于基本方程和边界条件的弱形式，给出相应的广义变分和不同形式的有限元所采用的弱条件，说明弱形式允许不是逐点满足，有限元法只在节点邻域平衡，在单元内不要求平衡，解析法用无穷级数中单取一项也不满足方程，也是无穷多项在积分下满足，进而导出对偶体系弱形式哈密尔顿方程。

First the three-dimensional Hailmuhz equation of magnetotelluric field is split into two 2D equations which could be changed into 1D equation by Fourier transformation method. The two zootomic coefficients of the equation are found out by the derivation of vertical component of electromagnetic field being sufficient the equation and the boundary condition. The resolution of 1D equation can be confirmed.

首先将大地电磁场满足的三维亥姆霍兹方程降维分裂成两个二维响应方程，然后对每一个二维方程进行傅里叶变换，使二维方程变为一维方程，通过大地电磁场垂向方向的导数在地面上所满足的边界条件，确定外推方程中的两个待定系数，从而得到一维外推方程的解。

The expression of one-dimensional mathematical model of vertical migration of ammonia in the CRI system is:The parameters in the CRI model are determined as following: the retardarce coefficient is determined by static isothermal absorption experiment, the velocity of sewage travel through the soil column is determined by permeability test, the vertical dispersion coefficient is determined by test the electric conductivity of tracer in the dispersion experiment, the rate of nitrification and denitrification is determined by test of Baps technology.

依据单一氨氮、硝氮配水条件下的试验结果，引入多孔介质的溶质运移理论及对流-弥散方程，考虑NH4+-N在CRI系统中的运移受到对流和水动力弥散作用的影响，并吸附-解吸、硝化与反硝化3个过程，首次将配水流经CRI土柱的孔隙水流速方程与CRI土柱内发生的、以氧为约束条件的硝化、反硝化过程联系起来，建立了CRI系统一维垂向氨氮运移转化数学模型，表达式为：研究分别通过静态等温吸附实验率定了模型方程中的阻滞系数、通过渗滤试验测定了土柱中的孔隙水流速、通过测定弥散试验中示踪剂的电导率确定了纵向弥散系数、通过气压过程分离技术测定了土柱中的总硝化与反硝化反应速率常数，最后通过测定土柱沿程氧化-还原电位的方法分析氨氮在CRI系统中的运移转化机理。

The transmission of heat differential equation for the heat conduction process of thermoelectric module was derived And the solution with the first kind boundary conditions under the influence of Thomson effect and the solution with the third kind boundary conditions without the influence of Thomson effect was obtained.

导出了电偶臂在电与热的偶合作用下传热微分方程，并对其进行解析求解：在考虑汤姆逊效应的影响下得出一类跟三类边界条件下传热方程的解析解，在忽略汤姆逊效应的影响下得出二类跟三类相的边界条件下传热方程的解析解。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。