查询词典 four dimensional

In order to prove the global asymptotical stability of the endemic equilibrium, we introduce the change of variable which can reduce our original four-dimensional system to a three-dimensional asymptotical autonomous system with limit system.

利用复合矩阵理论以及竞争系统的Poincaré性质排除了渐近自治三维系统的极限系统周期解的存在性，进而利用极限方程理论得到了原四维系统地方病平衡点的全局稳定性。

Via the stochastic averaging method, the four-dimensional system is reduced to a two-dimensional one. Through the logarithmic polar transformation , and then Girsanov theorem and Feynmann-Kac formula, the backword differential operator is then obtained. By expanding the eigenfunctions as a Fourier cosine series, the approximate analytic expansion of the moment Lyapunov exponent is then obtained.

首先在经典二元机翼颤振方程加入随机激励，通过随机平均法，Girsanov定理和Feynmann-Kac公式得到关于矩Lyapunov指数的特征值问题，其次采用Fourier余弦级数对特征函数进行正交展开得到系统矩Lyapunov指数的近似解析式。

It should be noted that here we only concern about the four dimensional case, neglecting other dimensional black holes.

需要说明的是本文只关心四维黑洞情形，不考虑其它维数的黑洞情形。

In the three dimensional space, with the involvement of time it brings the audience a four dimensional art experience.

大众游戏成为与先哲沟通的方式；熟悉的材质用以模拟现实场景，进行概念性试验。

In this paper, we investigate some interesting models of dark energy, especially the brane scenario, in which our four dimensional universe is embedded in a higher dimensional spacetime where the gravitation can propagate in.

在胚世界宇宙学框架下，我们所生存的四维宇宙被认为是镶嵌在更高维的时空中，而引力相互作用可以在整个高维时空中传播。

According to the theory of beam phase space, the projective density distributions in four dimensional and two dimensional trace space are derived for some space charge distributions often used in accelerator physics.

理论和实验研究都已发现，它们与束流空间电荷的非均匀分布有密切关系。

According to the theory of beam phase space , the projective density distributions in four dimensional and two dimensional trace space are derived for some space charge distributions often used in accelerator physics. And, the relation between beam emittance and brightness with density distributions is developed too.

针对加速器中几种常用的束流密度相空间分布形式，根据束流相空间理论，推得了它们在四维和二维径迹空间中的投影密度，并给出了束流发射度和亮度与束流密度分布的关系式，为加速器束流测量和束流诊断提供理论依据。

In this study we combined two-dimensional, Doppler, three- and four-dimensional echocardiography, Transesophageal echocardiography , and the new technique-acoustic quantification with radionuclide ventriculography and right heart catheter examinations a...

本研究利用经胸二维超声、多普勒超声、三维及四维超声、声学定量技术和经食管超声等多种超声技术，与核素心室造影、结合较为系统地对右心功能进行了研究。

The culture can be described in the four-dimensional or three-dimensional degree.

尽管对文化的度量存在一定的困难，但还是可以通过四维度或三维度法进行描述。

By taking the strategy of uniting geometry with algebra and using the method of minimal value, the relationships of intersection, parallels and perpendicular between two three dimensional spaces in four-dimensional descriptive geometry are investigated and the calculation formula of the distance between two three-dimensional spaces are given.

用形数结合的观点和条件极值法，研究了四维空间的两三维空间的相交、平行和垂直的相互关系计算出两平行三维空间的距离。

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。