对称中心

The results show that, when the computational error and its accumulation are eliminated effectively, the laminar flow in OFR with perfect-symmetric boundaries behaves in a pattern of central symmetry and circumferential uniformity while the turbulent flow field presents a centrally symmetric and circumferentially non-uniform structure with 8 transverse vortices arrayed circumferentially in a way of central symmetry, similar to Taylor vortices in Couette flow.

模拟结果表明在有效消除计算随机误差以及误差积累的情况下，几何边界理想对称OFR内的三维层流流场呈现出良好的中心对称性和周向均匀性，而湍流流场中心对称的同时呈现出周向非均匀结构－在圆周上生成8个中心对称排列的横向漩涡，其形态与Couette流中的泰勒涡类似。

On the western side of the central normal of the disturbance source in the heliospheric equatorial plane, the double shock pair structure is more evident, and the longitudinal span is wider than those on the eastern side.

双重激波对在子午面内相对扰动源中心法线基本对称，而在赤道面内则不对称：扰动源中心法线西侧双重激波对结构更为明显，所跨经度范围宽于东侧。

On the western side of the central normal of the disturbance source in the heliospheric equatorial plane, the double shock pa ir structure is more evident, and the longitudinal span is wider than those on t he eastern side.

双重激波对在子午面内相对扰动源中心法线基本对称，而在赤道面内则不对称：扰动源中心法线西侧双重激波对结构更为明显，所跨经度范围宽于东侧。

Necessary and sufficient conditions for the existence and the expressions of selfconjugate solution, perselfconjugate solution, centrosymmetric solution, bisymmetric solution, skewselfconjugate solution, skewperselfconjugate solution, skewcentrosymmetric solution, and skewbisymmetric solution to 4 kinds of systems of linear matrix equations over a regular ring with an involutorial antiautomorphism are given.

利用矩阵技巧和所建立的矩阵理论，给出了正则环上五类矩阵方程组有解的若干充要条件和一般解的表达公式。这些矩阵方程组除了它们在理论上有重要的意义外，还有重要的应用价值。在具有对合反自同构的正则环上，给出了四类矩阵方程组有双对称解，中心对称解，斜中心对称解，广自共轭解，斜广自共轭解，自共轭解以及斜自共轭解的充要条件及其这些解的具体表达式。

The second milestone was the development of bilateral symmetry ( two halves of the body mirror each other ) with an identifiable head , in contrast to radial symmetry ( symmetrical in a ray pattern from the center ), for example , jellyfish .

第二个重要事件是动物身体进化成两侧对称，并出现明显的头部组织。当然也有例外，例如海蜇这种生物就是径向对称（即对称点在身体中心，呈放射对称）。

The solution group such as symmetric, skew-symmetric, centrosymmetric, centroskew symmetric, reflexive, antireflexive, bisymmetric or symmetric and antipersymmetric are successfully found.

构造了一种迭代法系统地研究了问题Ⅴ的一般解组、对称解组、中心对称解组、自反矩阵解组、双对称解组、对称次反对称解组及其最佳逼近等问题，并成功地解决了这些问题。

Therewithal the symmetry about centrality had spontaneously breaken and had brought about the spacetime of multiverse, the mirror symmetry of CPT betweenthe universe of matter with antimatter centralized about The central black hole.

于是，中心对称自发破缺，产生正反物质世界以中心黑洞为中心的CPT镜面对称的多宇宙时空。

Therewithal the centric symmetry had spontaneously breaken and had brought about the spacetime of multiverse , which makes a feature of the mirror symmetry of CPT between the universes of matter with antimatter centralized about The central black hole .

于是，中心对称自发破缺，产生正反物质世界以中心黑洞为中心的CPT镜面对称的多宇宙时空。

Furthermore, the optimal approximation centrosymmetric solution pair to a given centrosymmetric matrix pair in Frobenius norm can be obtained by finding the least norm centrosymmetric solution pair of new matrix equation ,where .

另外，给定中心对称矩阵对，通过求矩阵方程的中心对称解对，得到它的最佳逼近中心对称解对。

The effect of the friction between rolls and ring can be ignored and the effect of the spread velocity of rolling on the deformation of ring is illustrated.

通过模拟分析比较，揭示出了环件轧制过程中的金属流动规律：轧制时，环件外侧的变形最大，厚向中心部位变形最小，内侧的变形程度介于中间；环件内外环面的压应力分布和变化规律：在垂直于环件轴线的对称面上，压应力分布近似对称状态，而且在对称面上的应力最大，往端面方向开始减小；指出了环件轧制中轧辊与环件摩擦对环件成形的影响：对于环件的宽展变形，摩擦的影响很小，可以忽略；分析了环件进给速度对环件成形的影响并阐述了环件厚向中心部位凹陷产生的原因，提出防止凹陷的措施：在轧制时，尽量使用快的进给速度有利于防止端面凹陷的产生；研究了导向辊位置对环件成形以及轧辊受力的影响：导向辊的位置对环件的宽展变形影响很小，但对轧辊的受力影响较大，当导向辊的中心位置位于毛坯初始中心位置之上时，驱动辊和芯辊的受力相对较小，这是导向辊导向时优先考虑的位置。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。