数值

In this paper, applying an integral expression of linear viscoelastic theory, several integral equation expressions for obtaining shear modulus G from stress relaxation modulus E{t and bulk modulus K are acquired by using inversion of the Laplace Transform.

本文应用线粘弹性理论的一种粘弹性积分变换式，采用拉氏逆变换，导出了由拉伸松弛模量E和体积松弛模量K求解剪切模量G的几种积分方程，并给出了由已知试验数据E和K通过迭代和数值积分求G的数值积分算法。

The main achievements of this dissertation are as follows: Let W be a nonsingular matrix. 1. Problem I and Problem II are considered under the matrix set S is as the following: 1 the set of real W-symmetrizable matrices; 2 the set of real W-symmetrizable nonnegative definite matrices; 3 the set of real W-symmetrizable matrices on the linear manifold.

对于问题I和问题II，本文就S是W可对称化矩阵集合、W可对称非负定化矩阵集合以及线性流形上W可对称化矩阵集合等三种情况进行了研究，分别给出了这三种情况下问题I的解存在的充分必要条件，以及解集合的通式表达式，给出了这三种情况下的最佳逼近解，并提供了相应的数值算法和数值实例。

According the characteristics of multivariable linear system, time-varying subspace identification method is studied, extending the ordinary subspace identification to the time-varying case.

定常系统的子空间方法利用SVD方法定阶，具有数值稳定的特点，但用于时变系统的辨识将导致大量的数值运算。

In order to improve the capability of Hooke's universal joints, the effects of structural parameters on the contact pressure distribution are analyzed based on Lundberg's logarithmic equation and the numerical calculation of three-dimension elastic contact problems in finite length.

为改善万向节的性能，文中基于Lundberg对数凸型方程和三维有限长弹性接触问题的数值计算，分析了轴承结构参数对接触压力分布的影响，提出滚针凸度量设计时必须考虑滚针倒角半径和越程槽宽度的影响，并给出了相应的数值计算方法。

The tensile strength and the elastic modulus were assumed to obey Weibull and logarithmic normal distribution and the other mechanical parameters were taken as constant values in the simulations of three-graded-concrete supported beam. The random aggregate random parameters model was established, which is very close to the actual structure. The results show that the nonlinear behavior of higher homogeneous specimen appears later obviously; the influence of random distribution of elastic modulus on the mechanical character is very little in linear range, while great in nonlinear range; random distribution of tensile strength affects the strength and the damage threshold of concrete obviously.

对三级配混凝土简支梁进行数值模拟时，假定各相材料的抗拉强度和弹性模量服从Weibull、对数正态两种随机分布，其他力学参数取定值，生成和实际结构比较接近的随机骨料随机参数模型，数值模拟结果表明材料均质度较高的试件出现非线性行为的时间要明显滞后于均质度较低的试件；弹性模量分布的随机性对材料线弹性段力学性能的影响极小，而对非线性区域的影响较大；材料强度分布的随机性对混凝土的强度和损伤阈值有较大的影响。

A dynamic model of the rotor system with slow-varying mass and pedestal looseness was set up.

建立了带有支承松动故障的质量慢变转子系统的动力学模型，利用数值积分和Poincare映射方法，对该转子系统由于支承松动故障而导致的动力学行为进行了数值仿真研究。

Finally, a Lorenz system is employed to verify the effectiveness of the proposed method, and the simulation results are shown in the end of this paper.

在本文最后，针对Lorenz系统进行了数值计算，数值计算结果表明了所给方法的有效性。

In the low-low satellite to satellite gravity mission, the intersatellite range and range-rate data are the observable values, while the intersatellite acceleration can be derived from the range-rate through digital differential. Using acceleration data, people can avoid solving the variation equations of the satellite motion and simplify the observation equations. But on the other side, the digital differential will amplify the observation noises and finally affect the solved geopotential accuracy.

低低卫星跟踪卫星的观测量是两低轨卫星的星间距离或星间速度，星间加速度由星间速度通过数值微分导出，用星间加速度作为观测量可以避免解算卫星运动的变分方程，简化观测方程的建立，但数值微分会使观测噪声放大，从而影响重力位的解算精度。

Based on the uniform magnetization model of the surface magnetic field distribution on multi pole drum for magnetic encoder , the surface magnetic field distribution on multi pole drum for magnetic encoder was studied with numerical analysis method, and the general expression of surface magnetic field distribution on multi pole drum was found.

基于磁编码器多极磁鼓表露场分布的均匀磁化理论模型，采用数值分析方法计算磁编码器多极磁鼓的表露场分布，得到了多极磁鼓的表露场分布的数值表达式。

Based on contraction mapping theorem of analysis mathematics, the non-steady flow mathematical model of mine ventilation network was analyzed.

利用分析数学的压缩映射原理，对矿井通风网络非稳定流动数学模型进行了分析，得出了数学模型数值解收敛的条件，确定了以惯性系数排序选择最小生成树的回路选择方案，为矿井通风网络非稳定流动数学模型数值解的收敛性提供了理论依据。

But we don't care about Battlegrounds.

但我们并不在乎沙场中的显露。

Ah! don't mention it, the butcher's shop is a horror.

啊！不用提了。提到肉，真是糟透了。