查询词典 fractional equation

Unfortunately, most of the analytical solution for fractional differential equation are complicated owing to complex series or special functions.

然而大多数分数阶微分方程的解析解含有复杂的级数或特殊函数，不利于近似计算。

We construct an explicit finite difference approximation for the equation by using the equivalence relation between Riemann-Liouville fractional derivative and Grünwald-Letnikovmake fractional derivative.

再利用Riemann-Liouville分数阶导数与Grtinwald-Letnikov分数阶导数之间的等价关系，构造一显式有限差分近似，这一离散格式可以解释为一个随机游走模型，并且收敛于稳定的概率分布。

The main research contents and results are described as follows:The constitutive equation of the elastomer modeled by the fractional derivative Maxwell model has been investigated. Based on the thermodynamics constraints analysis of the physical parameters of the fractional derivative Maxwell model, the relaxation modulus and the creeping modulus of the model are analyzed.

本论文针对该目的，采用理论研究与试验研究相结合的方法，首先研究了胶泥缓冲器的耗能机理，进而设计开发了较理想的缓冲器产品，具体研究内容和成果如下：研究了胶泥的本构模型——分数微分Maxwell模型。

Fractional Fourier transform procedures for the solution of fractional order equation provided some numerical method.

详细说明：分数阶Fourier变换程序，为求解分数阶方程提供了一些数值解法。

The sufficient conditions for achieving synchronization of this fractional differential system are derived by using the stability criterion of fractional linear equation.

用三种不同的方法考虑分数阶Lorenz混沌系统的修正投影同步，基于分数阶线性方程的稳定性理论给出了实现同步的几个充分条件，数值模拟说明了所给方法的有效性。

Because the characteristic equation of fractional order system is a pseudo-polynomial function with exponential-type fractional orders of complex variable, the control of integer orders cannot be directly applied to it.

分数阶系统的特征方程是一个具有复变量的分数阶指数的伪多项式，因此不能直接应用整数阶系统的控制方法。

Further analysis shows, the average fractional error between the related equation and the actual experimental date is 1.5% in 20℃. The related equation based on dimensional analysis can properly coincide with the actual result.

通过分析比较发现，20℃时关联式相对於实测数据的平均相对误差仅为1.5%，由此证明利用量纲分析得出的膜通量衰减关联式较好地反映了实验结果。

After introducing the generalized strain energy function with fractional order, the constitutive equation of biological visco-elastic material was obtained by means of the fractional calculus.

摘 要：对生物粘弹性材料，引入广义分数阶应变能函数以后，应用分数阶微积分分别给出了粘弹性固体和粘弹性流体的本构关系式。

At present,the rate laws and reaction mechanisms of pyrite oxidation,pyrite and chalcopyrite formation,uraninite and magnetite dissolution in aqueous solutions are mainly studied,and it is discovered that (1)oxidation rate of pyrite controlled by surface reaction assume fractional dependence on Fe3+ and O2 molalities in acid solutions;(2)Pyrite cannot nucleate directly from solutions below 300 ℃,it can only form initially through sulfidation of a FeS precursor. The rate equation of reaction between FeS and H2S to form pyrite is of the second order;(3)Chalcopyrite is formed by reactions of pyrrhotite or pyrite with Cu2+,the former proceeds via a series of mediate metastable phases of Cu-Fe sulfide,whereas the rate equation of the latter is apparently of the first order which is controlled by surface reaction;(4)The nonlinear behavior of magnetite dissolution at acid pH can be represented by a shrinking core model coupling with surface reaction and diffusion transport.

目前主要研究了水溶液中黄铁矿氧化、黄铁矿和黄铜矿形成、晶质铀矿和磁铁矿溶解的速率定律和反应机理，发现：(1)酸性溶液中黄铁矿的氧化速率对Fe3+和O2浓度呈分数依赖并受表面反应的控制；(2)低于300 ℃时黄铁矿不能从溶液中直接成核，而需初始地通过FeS先驱物的硫化生成，FeS与H2S反应形成黄铁矿的速率方程为二级；(3)磁黄铁矿或黄铁矿与Cu2+反应均可形成黄铜矿，前者经历了一系列准稳的Cu-Fe硫化物的中间物，后者的速率方程为表观一级并受表面反应的控制；(4)酸性pH时磁铁矿的非线性溶解行为可采用表面反应扩散输运耦合的收缩核模型来描述。

The second part is the controllability of parabolic equation .We study on the controllability of parabolic systems with a nonlinear term involving the state and the gradient ,the null-controllability property of a 1-d parabolic equation involving a fractional power of the Laplace operator ,null controllability of some systems of two parabolic equations with one control force ,and exact controllability of the parabolic system with bilinear control .

第二部分写的是，抛物方程的能控性，我们研究了含有状态和梯度的非线性的项抛物系统的能控性，含有拉普拉斯算子的分数阶的1-d抛物方程的零能控性，带有一个强控制的两个抛物方程的一些系统的零能控性和具有双线性控制抛物系统的精确能控性。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。