二次曲线

A method of construct a quadratic uniform B-spline curve through data points is given.If the relative curvature of a certain curve on the first control point and the direction angle of the first port's tangent vector is given,here can get the whole curve by using the character of the port of quadratic uniform B-spline curve.

提出了一种二次均匀B样条插值曲线的构造方法，首先给定某一段曲线首点的相对曲率和该段曲线的首端切矢量的方向角，利用二次均匀B样条曲线的端点性质，求出其余各段曲线控制顶点，来生成整条插值曲线。

Grain quality affected by N application and plant density could directly influence malting quality. Grain protein content was negatively correlated to steeping degree and steeping rate, and positively related to saccharogenic power. The relationship of grain protein content to a -Amino-nitrogen content and kolbach index could be expressed with a quadratic curve equation, respectively. The greatest decomposition rate of protein might be achieved when grain protein content was 11-12%.

施氮量、氮肥运筹比例和密度对籽粒品质的影响直接影响着麦芽品质，籽粒蛋白质含量下降，浸麦度和浸出率上升，糖化力下降，籽粒蛋白质含量和库值、氨基氮呈二次曲线关系，籽粒蛋白质含量在11%一12%时，其蛋白质分解速率最快，麦芽总氮与籽粒总氮呈极显著的正相关关系，在麦芽的生产过程中氮的消耗率与籽粒总氮为极显著的负相关关系。

7Sensitivity to rejection was positively and linearly related to sociometric status for boys but not for girls.

7男生方面，拒绝敏感性与社交地位有正的直线关系；女生方面则无直线或二次曲线关系。

3Affiliation tendecy was positively and linearly related to perceived sociometric status for boys but not for girls.

3男生方面，亲和倾向愈高，愈被认为是班上最受欢迎的人物；女生方面则无直线或二次曲线关系。

In first, a new short time formula of one dimension heat conduction differential equation, based on the theory of one dimension transient method, is presented for thermophysical property measurement of wood. The result of testing on red pine and larch wood arc satisfied by new method.In succession, the relationship between heat conductivity of wood and moisture, density, porosity, temperature and grain is studied experimentally in the range from 25 to 100℃. The result shows that, the heat conductivity is in direct proportion to density. but in inverse proportion to porosity. The heat conductivity of air-dried wood increased probably linear with the temperature rising. And that heat conductivity along the grain of wood is higher than that cross the grain. The former is 1.8 or 2 times of the latter.

文中研究了25～100℃范围内，气干木材的导热系数与含水率、密度、孔隙率、温度及热流方向的关系，研究表明：木材导热系数与密度成正比关系，与孔隙率成反比关系：对于针叶材，导热系数与密度及孔隙率成线性变化关系，而对于阔叶材其变化关系近似成二次曲线；气干木材的导热系数随着温度的升高近似呈线性增加：热流平行于纹理方向的导热系数大于垂直于纹理方向的导热系数，两者的比值大约在1.8～2之间。

A method for the determination of water soluble chloride content in iron ore by potentiometric titration was studied.

以2g/L硫酸钾为溶解试剂，硝酸银为滴定剂，电位滴定法测定铁矿石中的水溶氯，通过电极电位-浓度二次微商滴定曲线，计算二次微商等于零时对应的V为滴定终点，可省去绘制E-V曲线或ΔE/ΔV-V一次微商曲线作图带来的麻烦。

The linear improved algorithm is presented, and it has been proven to be well-posed. When the prior geometry informations are known, the line and conic-based algorithms are presented.

针对问题的病态性我们给出了线性改良算法，同时在已知某些先验几何信息情况下，分别给出了基于直线和二次曲线等几何特征的鲁棒性算法。

The article uses the theory of projective geometry to determine the polar and pole of self-conjugate of nonsingular conic without thinking about measure.

用射影几何的理论，抛开度量性质，给出了非退化二次曲线自共轭的极线与极点的射影定位，为现代设计提供了理论依据。

High School: Algebra, Geometry, Advanced Algebra, Trigonometry, Pre-Calculus conics and limits

高中：代数，几何，高等代数，三角学，微积分先修课二次曲线论和极限

The 2 g/L solution of potassium sulfate was employed for the dissolving of sample, and silver nitrate was used as titrant.

以2g/L 硫酸钾为溶解试剂，硝酸银为滴定剂，电位滴定法测定铁矿石中的水溶氯，通过电极电位-浓度二次微商滴定曲线，计算二次微商等于零时对应的V为滴定终点，可省去绘制E-V曲线或ΔE/ΔV-V一次微商曲线作图带来的麻烦。

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％。