特征方向

To all project practicality, the introduction is given to the operational characteristics, the methods for calculation and the researching actuality of the tail tunnels with sloping ceiling underground hydropower stations the Three Gorges. This paper has discussed in detail the characteristic method being the same with the compressive flow and the Priessmann solution being the same with the free-surface-pressure flow. And how to deal with boundary conditions has been expatiated. Also hydraulic transient process of tremendous load fluctuation in the tail tunnels with sloping ceiling has been numerical simulated and the Fortran program for numerical simulation has been given. The paper gain the maximal press for tail end of the shell, the maximal rising rate of rotational speed of generating set, the maximal vacuum degree for inlet of the tail tunnels and so on under 11 kinds conditions of tremendous load fluctuation. These conditions include the design conditions, the check conditions and the superposition conditions. Finally, the computing results have been analyzed and summarized. The end chapter is the general comment of the whole-length content and the describing of the intending view of researching.

本文以三峡右岸地下电站尾水洞设计为背景，从工程实际出发，阐述了变顶高尾水洞的工作特性、使用范围及其研究现状；详细论述了适用有压流的特征线法、适用明满交替流的普里斯曼解法等数学模型；边界条件的给定和明满交替流的计算方法；用Fonran语言编制了数值计算程序，对三峡右岸地下电站变顶高尾水洞的大波动工况进行了数值模拟，分别得出了在设计工况、校核工况和叠加工况下蜗壳末端最大压力上升值、机组最大转速上升值和尾水管进口最大真空度等重要参数；对数值计算结果进行了详细分析并得出了有价值的结论；最后展望了今后水电站变顶高尾水洞的研究方向。

The above characteristics of present-da y tectonic deformation of the northeastern Qinghai-XizangTibetan plateau may b e attribute d to the northeastward squeezing of the plateau and the resistance of the Ordos block, as well as the southeastward extrusion of the plateau materials.

该区现代构造变形特征可能与青藏高原向东北的挤压作用、鄂尔多斯地块的阻挡作用以及高原物质向东南方向挤出运动有关。

It is found that the off west coast of South Island of New Zealand earthquake has several basic characteristics as follows:① Moment magnitude is about M 7.8; Rupture duration time is about 40 s;② The static slip distribution is simple and the whole rupture process contains only one slip concentrated patch; This earthquake is mainly a unilateral rupture event with the rupture propaga ting southwestward.

结果表明。这次新西兰南岛西海岸近海地震的破裂过程具有如下基本特征：①矩震级约为M7.8；②地震主要破裂持续时间约为40 s；③滑动量在断层面上的分布比较简单，整个地震破裂只包含一个滑动量较大的区域；④这次地震基本上是一次单侧破裂事件，破裂主要朝向西南方向。

The results showed that the multi-cities of central Liaoning had a fractal hierarchical structure, their sizes were in primacy distribution, and middle-size cities were fewer. The spatial distribution of city size tended to balance hut the development process had significant regional difference. From 1982 to 2005, the gravity of urban population had an overall southwestward transfer.

结果表明：辽宁中部城市群城市体系等级规模结构具有分形特征，城市规模分布呈首位分布，等级序列中中等城市数量较少；城市规模空间分布趋向均衡，但发展过程具有显著的区域差异；从1982-2005年城市人口重心总体向西南方向移动。

Strabotomy could completely or partly eliminate diplopia, especially it could correct the restricted strabismus in the primary position and in the read location.

结论①视网膜脱离手术后斜视属于限制性斜视，其临床特征有助于指导对运动受限的肌肉做出准确判断和定位并进行斜视手术；②视网膜脱离手术后水平斜视的方向与主要牵制肌肉相反的情况由直肌下过度操作引起；③斜视手术可改善复视症状、矫正眼位。

Conditions for maintenance of reticulate dune morphology under modern flow environment include enough space for the development of secondary ridges on the primary ridges in order that the overall pattern can not be modified by the subdominant winds, and sufficient amount of sand supply for the secondary ridges that can withstand the dominant winds.

在背风坡，因原始气流方向、强度和沙丘背风坡形态等的不同出现弱的反向气流，相对强的附体未偏向流和附体偏向流等三种特征次生气流，它们控制着背风坡表面过程、沙丘移动性质、内部层理类型和产状。

For the special boundary condition and geometry profile of meandering river, when water going into together with sediment, the former character will change, such as the superelevation of water surface and the difference of pressure in the centripetal direction.

由于弯道特有的几何特征和边界条件，使得弯道中水流产生水面超高现象，从而在向心方向上产生压力差。

Psychology}, the paper defines intuition as a cognitive ability to make immediate judgement without analyzing or reasoning and further analyzes the relation and difference between intuition, inspiration, insight, imagination and perceptual intuition, pointing out that mathematical intuitive thinking is a swift judgement on and imagination to the objects of mathematics and their relationship in structure which is featured by illogicality, directness, probability, randomness and unity and aids students in predicting conclusion or direction to solution as well as making definite choice between several options, Furthermore, the paper probes into the foundation of mathematical intuitive thinking in terms of psychological mechanism, and thereupon holds it necessary to develop students mathematical intuition in that it does good to the excitement of creativity, improvement of overall qualities, all- brain development and optimization of mathematical thinking among students.

而数学直觉思维就是人脑对数学对象及其结构关系的一种迅速的判断与敏锐的想象，并探讨了数学直觉思维的生理机理基础，总结其特征有非逻辑性、直接性、或然性、随机性、整体性和综合性。在解题时直觉能帮助学生对结论或解题方向做出预见，也可以在推理面临多种可能性时，帮助学生做出果断的选择。

Focusing on the receiver function variation pattern changing wtih different back azimuths, we introduced different kinds of symmetric systems of seismic anisotropy used often, and summarized some possible causes of anisotropy formation. We show details about how to calculate the response of a stratified anisotropy model with symmetric axis of arbitrary orientation.

本文围绕接收函数在各向异性介质中的方位变化特征，从地震各向异性基本理论、成因入手，详细给出了具有任意对称轴方向的横向各向同性介质中理论接收函数的计算方法。

The experiments show that our method can avoid the tangential drift and preserve the feature of the mesh.

实验表明该算法可以有效的避免了切线方向的漂移，并且能够有效的保持网格特征。

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。