查询词典 profile drag

The characters of linear complexity profile of periodic sequences are investigat- ed. The relation between the continued fraction expansion of rational function and its 1- inear complexity profile is established. The expression of linear complexity profite is gi-~~en and a condition estimating the randomness of a sequence is presented. By the linear complexity profile, the bound of sphere complexity is proposed. A formula to record the number of sequences with given linear complexity profile is presented.

研究了周期序列的线性复杂度曲线特性，在周期序列生成函数的连分式展开式与线性复杂度曲线之间建立联系，给出了周期序列线性复杂度曲线的表达式；给出了判断序列随机性好坏的一个条件；利用线性复杂度曲线特性给出周期序列球体复杂度的一个估计；给出了具有给定线性复杂度曲线的序列个数的一个计数公式。

This thesis investigates the profile extraction and shape optimization on the result of topology optimization of planar compliant mechanisms. The main context includes the following work:(1) summarizing and analyzing the recent research status, some harvest and unsolved problems;(2) analyzing the conceptual design of planar path-generating compliant mechanisms and its mathematical model and tools;(3) Modifying the method of density contour as the method of profile extraction, and developing a method to optimize the density function in the profile extraction according to the requirement of the design of compliant mechanism;(4) developing a method to abstract the compliant mechanism into a form of links and joints by using the principle of connectivity on topology;(5) developing a method of shape optimization of planar path-generating compliant mechanisms, by representing the profile of the abstracted compliant mechanism as simple curves such as straight lines and arcs, establishing the models of the size optimization of the parameters of these curves, so that the compliant mechanism has a machinable shape;(6) At last, proving the feasibleness and effectiveness of the design method by making simulation design and validating it in FEA software.

主要工作包括：(1)分析了柔顺机构拓扑优化和形状优化的研究现状，分析了目前柔顺机构的研究重点、主要成果和尚未解决的问题；(2)分析了基于SIMP的柔顺机构概念设计方法及其相关工具和模型；(3)针对柔顺机构轮廓提取的特殊要求，提出了密度等值线法的改进方案，对密度函数插值点密度值进行优化，提出优化模型和选择优化算法；(4)根据轨迹输出平面全柔顺机构自身的形状特点，提出了轨迹输出平面全柔顺机构的抽象方法，即应用拓扑学上的连通性原理将柔顺机构抽象成杆件和结点形式，并对相应的数学原理进行了证明；(5)提出了平面全柔顺机构的形状还原和尺寸优化方法，对抽象的柔顺机构进行还原，将其轮廓还原成简单曲线的连接，从而建立尺寸优化模型，对机构进行尺寸优化设计，在得到可加工的机构轮廓的同时又能对关键部位进行特别处理；(6)进行了柔顺机构的数值仿真设计，并将所得设计结果导入商用有限元软件中进行仿真实验，证明了设计方法的可行性和有效性。

Firstly, a new design method of cam profile has been developed by using finite terms of Fourier Series in the cycle of cam angle as the basic equation of cam profile, so the difficulty of base circle wave existing in the method of resonant cam design can be eliminated. On the other hand, the method proceeds from the acceleration of cam profile, which makes the acceleration not only smooth and continuous, but also easy to be controlled, and the cam profile with good performance can easily be acquired.

此方法用以凸轮包角为周期的富立叶级数有限项作为凸轮型线的基函数，可以免去谐波凸轮设计时控制基圆波动的困难；此方法又是从凸轮型线的加速度曲线入手进行设计，使型线加速度不但光滑、连续，而且形状容易控制，便于设计出动力性能优良的凸轮型线。

Result The skewed parabolic profile is observed in CCA under 1:60 curvature and physiological average Reynolds number. As curvature and Reynolds number increase, the middle of horizontal profile appears sunken and the vertical profile is M-shaped. There are different profile shapes in different localities along the curved pipe.

结果 当颈总动脉的曲率等于1：60 时，在人生理平均流动雷诺数条件下，颈总动脉的速度剖面可用偏斜的抛物面来近似；当颈总动脉曲率增大或流动雷诺数增大时，弯曲平面上的速度剖面中部出现下凹趋势，垂直方向上出现M型速度剖面；沿管轴不同位置上的速度剖面形状不同。

The author analyzed the rotor profile according to profile designing principle, selected one-sided asymmetric cycloid (gear/pin arc-shaped profile) as model, and completed rotor profile calculation under given parameters.

依据型线设计原则，进行转子型线分析，具体选择转子型线类型为单边不对称摆线—销齿圆弧型线，完成给定参数下的转子型线计算。

According to the character of highway profile design, this paper repositions the role of the optimization design of profile and builds the optimization design models and solves the problems of profile optimization design successfully with genetic algorithm, owing to the fact that highway design need repeatedly modification, this paper also establishes the self-adaption modification models of plane and profile design.

根据纵断面设计的特点，重新定位了纵断面优化设计的地位，建立了纵断面优化设计模型，并应用遗传算法圆满解决了纵断面优化设计问题。针对公路设计需要反复修改的特点，建立了平纵面自适应修改模型。

A typical profile of Daqiao peatland in the Changbaishan Mountains is chosen for this study. The vertical distribution of major and selected trace elements in the sediments of the profile was determined. Its implications for the climatic change in the Holocene are discussed. The profile was compared with another standard profile named Jinchuan in this area.

本文选择长白山地区典型的泥炭剖面－大桥剖面，探讨其沉积物常量元素和微量元素的垂直分布规律及其对全新世气候变化的指示作用，并与该区另一代表剖面－金川泥炭剖面进行对比。

But it increases the viscous forebody drag including the skin friction drag and shock wave drag.

但却增大了包含摩擦阻力和激波阻力的粘性前部阻力。

The accurate prediction of drag is key to the design of the low Reynold′s number flight vehicle,and the accurate prediction of friction drag which is induced by separation and transition of the boundary layer is key to the accurate prediction of drag.

而与附面层分离和转捩相关的摩擦阻力的精确计算则是此类飞行器阻力精确计算的关键。

Test results showed that the bionic nonsmooth structures on the tail of the models can obviously reduce the drag due to the pressure drop, especially for the model riblet nonsmooth form, its pressure drag was reduced by 25.3%, and its total drag was reduced by 11.12%.

试验结果表明，布置在尾部的非光滑结构能够有效地降低模型的压差阻力，尤其是棱纹状非光滑形态模型，压差阻力降低了25.3%，总阻力降低了11.12%。

The circulation, consumption and reproduction of the trilogy have not only testified to its historical significance and literariness, but also invested it with new meanings.

该三部曲的流通、消费与再生产不仅验证了其历史意义及文学性，而切还赋予它以新的意义。

If he thought that he could buy me off, he would be wrong.

如果他认为他可以收买我，那他就大错特错了。