查询词典 unstable solution

A numerical calculation program is written up for the various solution methods in this paper and the program is being used in various aspects of inverse problem of environmental hydraulics, including inverse problem in reverse process of one-dimensional unstable diffusion, inverse problem in reverse process of convection-diffusion, inverse problem for the dispersion coefficient in water quality model, The inverse problem of coefficient identification for nonlinear Boussinesq equation, parameter identification inverse problem for water quality model, the inversion of parameter of BOD-DO water model, the inverse problem of the source of convection-diffusion, identification of the steady-state permeability for two dimensional isotropic medium, two-dimensional steady inverse problem of convection-diffusion and parameter identification inverse problem for two-dimensional parabolic equation, etc.

对本文提出的各种算法，编制了数值计算程序，并把它应用于环境水力学反问题诸多领域，包括污染物一维非恒定扩散逆过程反问题，对流扩散方程逆过程反问题，河流水质纵向弥散系数反问题，非线性Boussinesq方程反问题，河流水质多参数识别反问题，BOD-DO水质模型参数反演问题，对流—扩散方程源项反问题及二维恒定各向同性介质渗透系数反问题，二维定常对流——扩散方程及二维抛物型方程参数控制反问题等。

Generalized predictive control is a kind of advance control methods that is of strong robustness, can overcome the time delay of system effectively and is suitable to unstable non-minimum phase system. But it has the shortcoming of large computation load because of online solving the Diophantine equation, inverse matrix and recursion solution by Least squares. So four kinds of fast algorithms of GPC that don't need the mathematical model of plant and are highly real-time are proposed in the paper. They have laid the rationale for the application of GPC to systems that need fast response.

广义预测控制是一种鲁棒性强、能够有效地克服系统滞后、可应用于开环不稳定非最小相位系统的先进控制算法，但由于它需要Diophantine方程计算、矩阵求逆和最小二乘的递推求解，因此计算量很大，本文针对此缺陷提出四种不基于对象模型且实时性高的广义预测控制快速算法，为广义预测控制应用于实时性要求高的快速系统奠定了理论基础，具体研究工作如下。

Compared with the competing methods, the modified direct numerical method enables to avoid the unstable results during the initial period, and improves the solution accuracy and robustness significantly.

结果表明，修正后的直接法避免了计算结果的大幅振荡，使解的精度及鲁棒性能得到大大改善。

The equation is a Fredholm integral equation of the first kind which is extremely unstable. The solution of this equation is the brightness temperature of target.

本文建立天线模型得到天线温度方程，它是病态的第一类Fredholm积分方程，求解目标亮度温度也即求解这个积分方程。

When the plate vibrates in an oscillating magnetic field, the vibration may be stable, periodic or unstable depending on the solution of the Mathieu equation.

当薄板在交变磁场中振动时，薄板的振动可能是稳定的、周期的或不稳定的，这可归结为求解Mathieu方程。

Based on the elastic theory of large deflection and by taking into account the variation of the axial force and its effects on bending deformation of the drillstring in vertical section,the vibration of the drillstring induced by fluctuating weight-on-bit is described by a parametrically excited system.A Mathieu equation describing the system is established by Galerkin Method.By extending the solution into a Fourier series,the curves of dynamic bifurcation values and the dynamically unstable regions surrounded by the curves are presented.

基于弹性大变形理论，考虑到轴力沿钻柱轴线的变化及其对钻柱弯曲变形的影响等因素，将受自重作用的铅垂井段钻柱在波动钻压激励下的振动转化为一个参数激励系统，用Galerkin方法首次得到了描述此系统的Mathieu方程，并通过将方程的解展成富里叶级数的方法，得到了该振动系统的动力分岔值曲线及其所包围的动力不稳定区。

Through the comparison of energy, the asymmetric solution is stable while the symmetric one is revealed unstable.

通过变形发生分岔前后的能量比较发现，分岔后的对称变形是不稳定的，而非对称变形是稳定的。

Accord- ing to the observation that the compounds were stable in low pH aqueous solution and their sta- bility decreased when pH increased, and they rapidly decomposed to form α-methylenecyclopen- tanones derivative when pH reached 6 to 7, we postulated that the compounds were unabsorbable in stomack (where pH1-3) and unstable in small intestine (where pH5-8). The decomposed product was indeed inactive.

对Ⅰ类化合物在稀溶液中的稳定性研究表明，低pH时化合物较稳定，随着pH值的升高稳定性逐渐降低，pH6~7时，化合物迅速分解成α-亚甲基环戊酮类化合物，由此而推测Ⅰ类化合物经口给药无效的原因为：它们在强酸性的胃中（pH1-3）呈离子状态，因而不易吸收，经胃的排空运动进入肠道后，随着pH逐渐升高（pH5-8）化合物迅速分解，而分解产物α-亚甲基环戊酮类化合物证明是无效的。

An unstable acid known only in solution and as ''.

一种不稳定的酸，已知仅存在于溶液中或作为一种铬酸盐。

The curative solution to unstable HYSWAS has been presented and the relevant calculational results have proved its reliability.

对计算得出的运动稳定性不满足要求的HYSWAS，提出了相应的解决措施，并进行了定量的计算，证实了这些改进措施的可靠性

I can not negligent, he should do what?

我不能不在意了，他要做什么呢？

It is very dangerous to swim in the river alone.

一个人到河里游泳是很危险的。