二次曲线

For a general parametric curve/surface, we usually cannot compute its exact implicit form. Even though its exact implicit form can be computed, the curve/surface implicitization involves relatively complicated computation and the degree is higher. Moreover, it may have unexpected components and self-intersections. All these unsatisfied properties limit the applications of the exact implicitization. So finding curve/surface approximate implicitization has become a practical problem. In this paper, we present an algorithm to solve the approximate implicitization of a given parametric curve by using a quadratic algebraic spline curve.

由于精确隐式化过程不一定可以实现，即使可以实现隐式曲线曲面的阶数高计算复杂，并且具有不希望的自交点和奇异分支，从而限制了隐式化的运用，所以寻求参数曲线曲面的近似隐式化问题成为很实际又重要的问题，提出利用二次代数样条曲线来实现一般平面参数曲线近似隐式化的一种算法。

This method can guarantee continuity and one-order smoothness of the estimated failure rate curve.

基本思路是：对那些寿终时刻，分别用单位时间内的失效频率做为失效率的估计，然后用二次样条函数来拟合出失效率曲线，这种处理可保证失效率曲线的连续性与一次光滑。

The pencil of plane quadratic lines is the foundation for studying plane cubic curve and hig-her plane curves.

平面二次线束是研究平面三次代数曲线和高次曲线的基础。

Koblitz curves over a finite field of characteristic 2 and characteristic 3 disassembles k using prime element of simple Euclidean domain.To further improve the efficiency,presents an assumption of disassembling k based on prime element of quadratic Euclidean domain.

特征2和特征3的这类Koblitz曲线是以一次欧式环的素元来分解k，对此设想是否可以二次欧式环的素元为基底来二次分解k从而进一步提高效率。

At last, we gets the coefficients of rectifying curve ploynomial through the curves fitting of three order Hermite interpolation polynomial, second order interpolation polynomial, and presents a fitting methods of small current working.

本文对高压电动机测量用电流互感器在小电流工作时电流比值误差和角度误差进行了研究，通过对引起误差的各参数的深入分析，得到误差与电流的关系，并通过三次Hermite 多项式插值法、二次多项式插值法的曲线拟合，得到曲线多项式的各系数，提出一种小电流工作时的拟合方法。

The parametric representation of segment can be gained from quadratic patch and constrained equations with cubic patches.

利用二次曲面的参数形式，由三次曲面片可得到曲线的隐参数约束形式，从而得到曲线的参数形式。

For equidistant knots, the trigonometric polynomial curves of first and second degrees are C^1 continuous, and those of third degree are C^3 continuous.

对于等距节点，一次和二次三角多项式曲线是C^1连续的，三次三角多项式曲线是C^3连续的。

This conclusion corrects a mistaken resultIn the planar quadratic system there is not cubic algebraical saddle-nodeseparatrix-loop,in which the author asserrts that quadratic system has no the cubicalgebraical saddle-node separatrix cycle .

本文证明了平面二次系统的三次代数同宿轨线上可以存在鞍结点，并且二次系统可以存在含鞍结点的无返回映射三次曲线分界线环。

This current is extra high and exceeds the permitted value of 10 % error curve of protection current transformer.It will affect the performance of relevant protection equipment.

文中以n次曲线模拟TA铁心饱和时的非线性磁化曲线，由此导出TA回路的非线性微分方程，并采用数值方法计算出在典型暂态短路电流作用下的TA二次电流波形。

At last, using the dual-porosity model, which is provided by LOGES logging interpretation system, two parameters of gas saturation and irreducible water saturation are used to help identify the doubtful pays with low resistance.

首先校正测井仪器或测井环境对曲线质量的影响，在此基础上进行标准化处理；然后通过&四性&关系研究，考虑到涩北气田储层欠压实等影响，采用补偿密度—电阻率交会的方法来编制气层解释图版，先对曲线进行一次解释，将易于识别的测井响应特征明显的气层剔除出来，然后对低阻可疑气层进行二次定量识别；最后，借助于LOGES测井解释系统提出的双孔隙度模型，利用可动水饱和度和地层水含气饱和度相结合建立新的测井解释标准，进而准确识别低阻可疑气层。

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％。