查询词典 line integral

A systematic study on computing the integral curvature line on NURBS surface is presented. Discrete normal is used to simplify calculation of the second fundamental form of the surface, resulting in accelerating the Euler iteration process in solving the differential equation of curvature line. Discrete points on the curvature line are then obtained and approximated by an explicitly presented B-spline curve on the NURBS surface using singular mixed interpolation and capable of controlling the error within a given tolerance.

对NURBS曲面的曲率线的积分进行了系统的公式推导，并利用NURBS曲面的离散法向量有效地简化了曲面第二基本量的计算，加速了Euler法迭代求解曲率线微分方程的过程；在求得曲率线上的离散点集以后，应用奇异混合插值技术，在可控精度内把曲率线用显式直接表示为位于NURBS曲面上的B样条曲线。

The subsection integral is used to get a simple function at first in the numerical calculation, and boundary integral is realized by gauss integral on each panel and line, then the complexity and isstability as a result of the high frequency surge function can be avoided.

数值计算中，首先采用分部积分对被积函数进行简化处理，然后采用高斯积分实现面元和线元上的积分，避免了被积函数为高频振荡函数所带来的数值计算的复杂性和不确定性。

The axially symmetric torsion of rigid circular shaft of varying diameter embedded in an elastic half space is studied by line-loaded integral equation method, where the problem is formulated by distributions of fictitions fundamental loads PRCHS (point ring couple in half space) along the axis of symmetry in interval of the shaft and is reduced to a one-dimensional and non-singular Fredholm integral equation of the first kind and is easily solved numerically.

弹性半空间；本文用线载荷积分方程法研究嵌在弹性半空间的刚性变直径圆轴的轴对称扭转。利用将"半空间的点环力偶"这一虚的基本载荷沿对称轴的圆轴区间中分布就能使本问题归结为一个一维的非奇异的Ferdholm第一种积分方程，且很易用数值求解。文中给出刚性圆锥，圆柱，圆锥柱嵌在弹性半空间的扭转的数值计算的例并和他人的已知结果相比较。

In the paper, with the characteristics of the line integral road, free surface condition and continuity condition, we gave the additional equations to close the equation group and overcame the difficulty, and successfully calculated and analysed the nonlinear ship wavemaking by the method.

文中根据自由面线积分路径的特点，自由面边界条件以及连续性条件来建立补充方程，而成功地解决这一难题，从而为非线性船波分析提供了一个有力的工具，并利用此方法分析非线性兴波取得了成功。

Firstly,the color image is sharpen by Unsharp Mask to extract detail information,and color scaling is used to strength contrast degree.Secondly,stroke direction is generated by the method of vector field.Finally results of the pencil-drawing are gained by the line integral convolution algorithm.

首先对用户输入的图像进行Unsharp Mask锐化提取细节信息，并进行颜色放大处理以增强对比度，然后采用基于点的向量场技术生成笔画方向，最后应用线积分卷积得到具有素描风格的结果图像。

In order to create a virtual flow analysis system, three algorithms (Marching Cube, LIC——Line Integral Convolution,and IBFV—— Image Based Flow Visualization ) were improved in their real time, objective and realistic aspect.

首先研究了CFD计算所必须的、也是耗费人工最多的网格生成技术，及其与CAD系统的集成。

First local surrounding-line integral bispectrum feature is extracted from the bispectrum of one dimensional range profile of space target, then BP neural network is used for target identification so that the network weights will not be the local lowest value.

提出了基于局部围线积分双谱的空间目标识别算法，从空间目标距离像的双谱中提取出局部围线积分双谱特征。

First, structure tensor is calculated to gain vector field for characterizing local structure of image. And then, total variation partial difference equation is imposed for smoothing vector field. Based on this we use line integral convolution for guide the stroke to generate virtual special effect image with fluctuant sense. Last, mergering with original real image, cylindrical panorama with virtualized relationship controlled by time can be generated, which accomplished the character of surpass the time and space in virtual reality system.

该方法通过计算结构张量获得图像曲线走向矢量场，以此刻画图像局部结构；并采用全变分偏微分方程对曲线走向矢量场自适应滤波平滑处理；在此基础上利用线积分卷积指导画笔走向模拟生成线条波动感虚化效果图像；最后结合原始真实图像和虚化效果图像，实现了一种基于时间变量的柱面场景虚化关联算法，并为虚拟现实系统超越现实时空的需要提供了一种新思路。

According to the plane cross section assumption, configuration of a rod is expressed as a history of the cross section with arc coordinate. A special solution which stands for equilibrium in straight line state is obtained from differential equilibrium equation. Linear perturbation equation is derived and its general solution is obtained in which the integral constants are determined by constrained conditions at two ends of the rod. The condition of existence of non zero solution of the integral constants gives to the Greenhill formula of exact elastic rod model, which shows that the boundary of stable area is a closed curve and of symmetry, and inference of shearable and extensible to stability of the rod is depend on three factors: difference between flexibility of shear and extension of a section of the rod, bending stiffness and the length of the rod.

基于平面截面假定，弹性杆的位形表达为截面的弧坐标历程，根据平衡微分方程得到了两端受力螺旋作用时的直线平衡特解，导出了线性化扰动方程及其通解，积分常数根据两端铰支时的边界条件确定，并根据其存在非零解的条件得到弹性直杆精确模型的Greenhill公式，表明稳定域为一对称的封闭区域，拉/压和剪切对稳定性的影响取决于：拉/压柔度与剪切柔度之差，抗弯刚度和杆长这三个因素

Two different line-integral paths around a crack tip. Image courtesy of Subra Suresh.

两条围绕裂缝尖端的线积分路径（由Subra Suresh绘制。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。