查询词典 backward difference operator

The problem gives a practicable methods to solve the existence and multiplicity of periodic and subharmonic solutions of second order forward and backward functional difference equations.

论文研究的问题和所得的结论具有比较重要的理论价值和应用价值。论文思路清晰，逻辑性强，推理严密，结论具有创新性。

Founds three-dimensional analytic model and analyses heat transfer with phase change with the help of numerical simulation software using Euler backward difference.

通过实验分析了冰水两相流在垂直和水平管道流动时的压降特性；建立了冰融解的三维分析模型，采用欧拉向后差分法，利用ANSYS数值模拟软件对冰水相变传热进行了数值模拟分析，得出冰粒大小与融解时间两者的关系曲线。

We found that it is the effect of odd-order term of f which describe the total energy collocation between forward wave and backward wave that causes the difference of modulation instability between normal dispersion region and abnormal dispersion region.

第三，根据增益谱的比较，我们从色散关系式中看到了产生这种变化的原因。正是由于存在f奇次项的影响而导致了这种在正常色散区和反常色散区变化趋势的不同。

Look from historical condition,; of economic technology instability looks from external environment, the infrastructure such as traffic, communication, irrigation works is backward, invest good environment difference, return rate is low.

从历史条件看，经济技术基础薄弱；从客观环境看，交通、通讯、水利等基础设施落后，投资硬环境差，回报率低。

While using three—points backward finite difference to imitate the radiation condition, we accept Raven's〓 idea to shift collocation points upstream a short distance.

在用三点向后差分格式模拟辐射条件时，接受了Raven〓的建议，将单元控制点向后移动了一段距离。

By analyzing the reason of the numerical oscillation phenomenon and computing the temperature field in plate rolling process,it is found that numerical oscillation can be restrained effectively when the heat capacity matrix is lumped by using backward difference scheme.

近年来，许多研究人员采用有限元法分析热轧和淬火等过程中的瞬态温度场。

An improved derivative estimation algorithm with a low-pass filter that can suppress the influence of high-frequency noise is suggested to remove potential drawbacks of the backward difference that was applied in neural network inversion dynamic compensation method, such as large estimation error in the presence of noise and price increase of hardware realization when high estimation accuracy is required.

针对神经网络逆动态补偿策略中基于向后差分的微分估计算法在噪声环境下存在较大的微分估计误差，且提高估计精度会增加硬件成本等缺陷，提出了改进的微分估计算法，并以加速度传感器为例，设计了动态补偿实验装置，给出了基于改进的微分估计算法的动态补偿算法的实现步骤。

The control volume integration was applied to deduce the discrete expressions of the convection-diffusion equations. The staggered grid and SIMPLE algorithm were introduced to deal with coupling between pressure and velocity, and then the numerical computation expressions of such variables as fluid flow velocity and pressure were deduced. Using the backward difference method and incremental theory to discretize the governing equations for fields of chemical reaction, material structure and chemorheology, the numerical computation expressions of variables such as the monomer conversion, average molecular weight and fluid viscosity were constructed.

应用控制容积积分法导出了对流—扩散方程的离散表达式，引入交错网格技术与SIMPLE算法，实现了耦合的压力场与速度场的分离式求解，推导得到了流体的流动速度、压力等物理量的数值计算式；采用向后差分方法和增量方法，实现了化学反应场、材料结构场、化学流变场控制方程的离散，获得了反应转化率、聚合物平均相对分子质量、流体黏度等物理量的数值计算式。

Those equations are dispersed in space by iso-parameter elementmethod and in time by using backward difference. A numerical simulator is established byFortran, the ideas of high part make the of structure program clear, maintain easy, calculationeffective.

在此基础上利用Fortran语言编制了有限元方法的油藏模拟器，采用等参元对渗流方程在空间上离散，采用向后差分在时间上离散，线性方程组的求解采用变带宽高斯消去法，该方法充分利用刚度矩阵呈条带状和其对称性的特点，大大减少了所需存储空间。

All sorts of inland river that have at that time from Guangdong carry shipping to look, because scientific guiding and management are lacked on boat type development, let things drift, so although have a few better ships type, but quite all sorts of one part is major even carriage shipping is dated and backward, line difference, draft is late, boat engine paddle does not match, speek of a ship or plane is small, cost can be high, economic benefits is poor, hang ship of paddle motor vessel especially.

从广东当时所拥有的各种内河运输船舶来看，由于在船型机型发展上缺乏科学的引导和治理，放任自流，所以虽有一些较好的船型机型，但相当一部分甚至大部分各种运输船舶都陈旧落后，线型差，吃水深，船机桨不匹配，航速低，耗能高，经济效益差，非凡是挂桨机船舶。

Now he worked in ajoint venture.

现在他在一家合资企业工作。

More troops in Afghanistan won't change any of the foregoing.

更多的在阿富汗的军队也不会改变之前的状况。