阶数

Firstly, based on the method of pressure-velocity coupling introduced by SIMPLE algorithm and a revised method of solving the unsteady equation of stream function and vorticity on uniform grid, a special algorithm called primitive-variable-time-dependent approach is formed in the present study. In this algorithm the Navier-Stokes equation in primitive variable form is solved by using the time-dependent approach on non-uniform staggered grid system. The second-order accuracy finite difference is used for the first and second partial derivatives of all variables of the convective terms and diffusion terms.

首先，本文在SIMPLE算法系列处理速度与压力耦合问题的思路和均匀网格下改进的关于流函数涡量方程的数值求解方法的基础上，将非定常原始变量Navier-Stokes方程的求解推广至非等距交错网格剖分，形成了具有本文特色的原始变量时间推进方法，其中对流项和扩散项中各变量的各阶导数均采用二阶精度公式，包括温度在内的离散方程组采用ADI迭代方法求解。

This paper discusses the connection of one step or two step right derivative and protruding property of a function.

研究了函数的一阶及二阶右导数与函数凸性的关系，推广了数学分析中的有关结果。

The existence of solution is studied for a class of second - order periodic boundary value problems with first applying Leray - Schauder fixed point theorem, two exislence theorems are established.

考察了一类非线性项含有一阶导数的二阶周期边值问题的解的存在性，其中非线性项是Carathèodory函数。通过构造非线性项的高度函数并且利用Leray-Schauder不动点定理建立了两个存在定理。

By constructing suitable cone and applying the decomposition technique of equation,the positive solutions are investigated for a class of semilinear fourth-order boundary value problem s with first derivative.

通过构造适当的锥并且利用方程的分解技巧研究了一类含一阶导数的半线性四阶边值问题的正解。

By constructing suitable cone and applying the decomposition technique of equation, the positive solutions are investigated for a class of semilinear fourth-order boundary value problems with first derivative.

通过构造适当的锥并且利用方程的分解技巧研究了一类含一阶导数的半线性四阶边值问题的正解。

The major implementations of the developed model include: Pseudo-spectral and finite-difference schemes are employed to approximate the spatial-differential operators in the horizontal and vertical directions, respectively. A second-order Runge-Kutta method is adopted to integrate in time for the velocity field and the free-surface elevation. The solenoidal condition of the velocity field is satisfied by solving the transformed pressure Poisson equation. A modified secant method is used to accelerate the iterative solution of the non-separable Poisson equation.

模式的主要数值方法包括：分别以拟频谱法以及二阶有限差分法近似控制方程与边界条件中的水平与垂直导数；以二阶Runge-Kutta法进行非稳态的自由液面位移与流场速度的时间积分；利用改良式割线叠代法求解计算区间中不可分离的压力Poisson方程式，以满足不可压缩流条件。

This paper attempts to find a lower-order state space symmetric model whose model reduction cost differs from the optimal model reduction cost by a prescribed precision.

该文试图寻找一个低阶隐定连续线对称性时不变系统，其与给定的高阶隐定连续线对称性时不变系统的L2 -范数误差可与最优误差值充分接近。

The obtained results indicate that in the case of Riemann-Liouville definition, theequivalence between FDEs and weak formulation does not require any initial conditions.

上述研究结果表明在Riemann-Liouville分数阶导数定义的情况下，分数阶扩散方程与弱形式的等价性证明不需要添加初值条件。

In Chapter 3,we derive the second-order-derivative-free iterations with two parameters from the third-order iterations with one parameter to approximate the roots of nondifferentiable equations in Banach space.

第三章，从带一个参数的三阶迭代族出发，构造了一族免二阶导数计值带两个参数的迭代族，用其去逼近Banach空间中非线性算子方程的解。

It is proved that Newton iteration method is still quadratically convergent under a weak condition, and a new point is added to Newton s method , i.

本文讨论求解非线性方程的牛顿法，证明牛顿法在一个弱条件下仍保持局部二阶收敛性，给出牛顿法的一点改进，即一个不带导数的单参数的二阶收敛的迭代法，而且分别得到这两种迭代法的收敛因子，最后进行数值实验

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。