曲率

The surface representation in discrete form and its differential computation are important issues in computer graphics and geometric design.

0引言一般来说，曲面的一阶微分量是指曲面的切平面方向和法向量，二阶微分量是指曲面的曲率等有关量·它们作为重要的曲面信息度量指标，在计算机图形学，机器人视觉和计算机辅助设计等领域发挥了重要的作用·传统的曲面是连续形式的参数曲面和隐式曲面，其微分量的计算已经有了较完备的方法·随着激光测距扫描等三维数据采样技术和硬件设备的长足进步，以及图形工业对任意拓扑结构光滑曲面造型的需求日益迫切，离散形式的曲面———细分曲面、网格曲面和点云曲面正在逐渐成为计算机图形学和几何设计领域的新宠·于是，对这种离散形式的曲面如何估

Chapter 1 is devoted to investigating the idea, history and development of the classic differential geometry.

同时，基于数学软件Matlab，在计算机上实现了上述问题的程序化，证明了该方法的有效性和优越性，并给出了各种实例图像和一些曲率结果的比较。

Next, what have double input and variable of 2 dimension appearance in the light of a kind is nonlinear system, used opposite curvature concept and curve to design controller of contract of appearance of 2 dimension plane by basic theorem, the curve of contrail of appearance be accusinged that controller of contract of this kind of appearance can assure a system and referenced contrail curve have identical figure.

梗概： 针对一般控制系统，利用微分几何中的曲线理论提出了外形变量、被控外形轨迹曲线和外形合同控制等概念。然后，针对一类具有双输入及二维外形变量的非线性系统，利用相对曲率概念和曲线论基本定理设计了二维平面外形合同控制器，这种外形合同控制器能够保证系统的被控外形轨迹曲线和参考轨迹曲线具有完全相同的外形。

And changes of their naked visual acuity, diopter, axial length and corneal curvature were observed and recorded.

随机选取52例在我院视光中心就诊的年龄在9～18岁近视患者配戴近视回归镜作为治疗组，观察裸眼视力变化，屈光度变化，眼轴长度及角膜曲率变化情况。

The error is bringed because the post-vertex of the eyeglasses is not superposition with the post-focus of the objective of the dioptometer.

由于被测镜片的后表面曲率各不相同，致使镜片后顶点与焦度计物镜后焦点不相重合，因而造成测量误差。

METHODS: The central corneal thickness, intraocular pressure, dioptre and corneal curvature were measured in 137 han nationality cases(274 eyes) and 115 Uygur myopia patients(230 eyes).

目的：分析维吾尔族与汉族近视患者中央角膜厚度(central corneal thickness，CCT)是否存在差异，了解维吾尔族近视患者中央角膜厚度与角膜曲率、眼压值及屈光度关系。

We use discrete Ricci flow to find these two special metric from special prescribed target curvature.

这些度量是通过对目标曲率进行特殊的设置，然后由离散的Ricci流计算而得。

Analyse the distributive law of shear-lag effect and influence of each structural parameter: pile length , bending stiffness of pile, bending stiffness of abutment, abutment length, different type of soil behind abutment, curve radius, width to span ratio,width of beam, etc. And the main influencing parameters were picked up.

进行结构参数分析，研究等代桩长、桩的纵向抗弯刚度、桥台纵向抗弯刚度、桥台高度、台后土压力、曲率半径、宽跨比及箱梁肋板间距等对剪滞系数的影响，从而得到影响无伸缩缝曲线箱梁桥剪力滞效应的主要参数和次要参数。

The position and size of the monochromator, focusing curvature radii and tilting angles of the germanium focusing monochromator under different different take-off angle, size and divergency of the second collimator and intensity loss due to the use of it were determined. The neutron flux at different wavelength, under different reflection and take-off angle of the monochromator and divergency of the first collimator, were given. The simulation on the aperture used for limiting beam size in front of the sample showed that, smaller the size of the aperture and further the distance from the aperture to the sample, greater the loss of the intensity and more serious the spread of the beam along vertical direction at the sample position which makes the practical sampling volume greater than expected.

用蒙特卡罗模拟方法对中子应力衍射谱仪的设计方案进行了优化研究，提出了一系列可供参考的数据：确定了单色器的位置、尺寸、垂直聚焦单色器在不同起飞角下的聚焦曲率半径和倾角；讨论了第二准直器的尺寸和发散，以及使用第二准直器造成的强度损失；给出了在不同单色器反射面、起飞角、中子波长和第一准直器发散度的情况下样品处的中子注量率，以及多种组合情况下谱仪的分辨率曲线；对限束方孔的尺寸、距离样品远近对强度损失和测量中的影响做了深入研究。

The basic formulations for the double nonlinear finite element analysis of drillstring in the large curvature wellbore are set up, and the Newton-Raphson iteration method is employed to solve the non-linear equations.

在此基础上，建立了对大曲率弯曲井眼中的钻柱进行二重非线性有限元分析的基本方程，以及相应的牛顿－拉斐逊迭代求解技术。

Lugalbanda was a god and shepherd king of Uruk where he was worshipped for over a thousand years.

Lugalbanda 是神和被崇拜了一千年多 Uruk古埃及喜克索王朝国王。

I am coming just now,' and went on perfuming himself with Hunut, then he came and sat.

我来只是现在，'歼灭战perfuming自己与胡努特，那麼，他来到和SAT 。