特征方程

Through the analytical solutions of momentum differential equation for a stream with varying mass, a general characteristic parameter , depending on structure scale and flow parameter, is introduced.

在径向流体分布器的变质量动量方程理论模型的基础上，通过对模型解析解的分析，获得了包括径向分布器结构尺寸和流动参数的特征参数k／C。

For nonstationary Stokes problem ,materials'anisotropic character should be considered in a boundary layer or near the angular of the domain fJ.

对发展型Stokes方程，由于边界层或区域的拐角处需考虑物质的各向异性特征。

According to the change of the enemy\'s quantity and the qualitative theory of the differential equation, we research the spruce aphides and its predator system. At the same time, we discussion the spruce aphid multiplication model when the natural enemy quantity is a certain value and the periodic oscillating model whose the quantity of the natural enemy changes along with the time. Obtains the stability condition of the balance point and the limit-cycle existing condition, the system presents the dissipative structure\'s character. Finally it explains that this theoretical analysis has certain practical significance regarding the preventing and controlling harmful insect.

第五章，松毛虫与其天敌的关系是食饵和捕食者的关系，根据天敌数量的变化，利用微分方程定性理论，研究松毛虫与天敌系统，讨论天敌数量为一定时的松毛虫增殖模型和天敌数量随时间变化的周期振荡模型，得到正平衡点全局稳定性和极限环的存在条件，通过计算机模拟，说明周期振荡的捕食模型能够呈现典型的时间耗散结构特征，对于防治害虫有一定的实际意义。

We employ maximum principle argument to get an error of size O.

3.3中考虑一类非线性对流扩散方程的特征差分格式。

On the basis of the 1 degree girded data of the seasonal mean temperature and salinity at standard levels in the South China Sea, mean Brunt-Visl frequency profiles were derived in order to compute numerically the vertical normal-mode for different seasons in various part of the South China Sea, and the associate linearized equation for horizontal large-scale waves is solved numerically with a improved thompson-Haskell algorithm.

根据南海1°×1°网格的标准层季节平均温、盐度资料，在未引入Boussinesq近似条件下，采用改进的Thompson-Haskell算法求解线性化斜压海洋水平大尺度波的垂直结构方程，从而得到了南海各网格点的第一斜压重力波相速度和相应的罗斯贝变形半径，并探讨其地理分布和季节变化特征，以期有助于南海环流和中尺度涡旋以及有关海洋侧边界效应的研究。

In this thesis, we take the delay r as a bifurcation parameter to investigate the Hopf bifurcation phenomenon in system (1). By analyzing the associated characteristic transcendental equation of system (2), and using the Hopf bifurcation theorem, we obtain one condition for the existence of Hopf bifurcation in system (1). Furthermore, based on the center manifold theorem and the method of normal form, some interesting results about the properties of Hopf bifurcation are obtained, including the direction of Hopf bifurcation and stability of Hopf bifurcating periodic solutions.

我们以时滞T作为分支参数，研究了系统(1)的Hopf分支现象：通过分析系统(2)的特征超越方程，结合利用Hopf分支定理获得了系统(1)的Hopf分支存在的一个条件；利用中心流形定理和正规形方法分析了系统(1)的Hopf分支的性质，包括分支的方向和分支周期解的稳定性。

The former researches on land price, usually treating spatial structure change as astatic one, often use Hedonic Model to depict the spatial variety of the whole studyarea. This research method hypothesized that the error items were dividedindependently and equally.

过去关于地价的研究主要视地价的空间结构变化为静态，多以特征价格方程等方法全域刻画地价空间变化，将误差项假设为独立与相等的分配，这样所得到。

In this paper,the asymptotic property for two kinds of ecological systems and oscillation for solutions of a neutral differential equations is studied by employing differential inequalities and using eigenvalue analysis,iterative algorithm,induction and comparison theorem etc.Here, the system\'s asymptotic property includes the uniform persistence,the global attractability of the solutions,the asmptotic stability of the solutions and the oscillation of solutions.

本文利用微分不等式、特征根分析法、迭代法、归纳法及比较原理等方法和理论，研究了两类生态模型解的渐近性和一类脉冲中立型微分方程解的振动性，其中包括模型的一致持久生存性，正平衡态的全局吸引性、局部与全局渐近稳定性以及解的振动性。

This paper presents a new method for an estimation of the axis of rotation based on line element geometry and kinematic equation.

提出了一种基于线元几何与运动方程的旋转体点云数据特征分离与旋转轴提取算法。

While the fluid flows up along relative close and wider rift system under overpressure , its nature is close to pressure conduit flow in fluid mechanics,which could be described by Bernoulli equation.

流体在相对封闭的较宽阔的断裂系统中受超压作用上侵流动时，其性质接近于流体力学中有压管流的流动情况，其动力学特征可以用柏努利方程进行描述。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失