半长轴

When the elliptical coaxial line becomes a circular coaxial line, the mode eigenequation of the circular coaxial line can be obtained from the mode eigenequation of the elliptical coaxial line using the asymptotic formulae of angular and radial Mathieu functions.

研究表明：当椭圆退化为圆时，利用角向和径向马修函数的渐进关系，可得到填充多层介质的圆形同轴线的模式特征方程，由此可见，圆形同轴线可看作椭圆形同轴线的特例；当椭圆同轴线内导体半长轴大小为零时，则椭圆同轴线就变成椭圆波导，同样的方法，可得到填充多层介质的椭圆波导模式特征方程。

Secondly, the analytic expressions of the error band boundary line for the s model of line segment are deduced, the parameter equations of the error band boundary are gotten.

考虑实用性和合理性，将线元看成离散点的集合，将线的不确定性看成点的不确定性的聚合体，将线元的位置不确定性模型看成以各点误差椭圆的长半轴E为半径的误差圆的聚合体，建立了以线元上任意点处的误差椭圆的长半轴E为带宽的线元不确定性ε模型。

In 1976, the International Astronomical Union revised the definition of the AU for greater precision, defining it as that length for which the Gaussian gravitational constant takes the value 0.01720209895 when the units of measurement are the astronomical units of length, mass and time.

但实际上地球绕日的轨道不是一个圆形，而是一个椭圆形：最初天文单位的定义就是上述椭圆的半长轴的长度。1976年，国际天文学联会把一天文单位定义为一颗质量可忽略、公转轨道不受干扰而且公转周期为365.2568983日的粒子与一个质量相等约一个太阳的物体的距离。

By Visual Basic 6.0 program, taken the distance between hole 200mm and buried depth 120～150mm as the optimization goal, the most optimum parameters range of the mechanism was obtained as follows: the initial angle between planet frame and the line formed from spraying-fertilizer needle-tip and planet wheel axle was -45°～-40°, the initial angular displacement of planet frame was 40°～50°, the distance between spraying-fertilizer needle-tip and the planetary gear axle center was 280～300mm, simultaneously, the semi-major axis of elliptic gear was 29.364mm, the teeth quantity was 23, the ratio of semi-minor axes and semi-major axis was 0.958, the radius of circular gear was 25mm.

对该机构进行运动学分析，建立了数学模型，以穴距200mm和入土深度120～150mm为寻优目标，应用Visual Basic 6.0软件编程得出满足机构运动要求的最优参数范围为：喷肥针尖和行星轮轴连线与行星架的初始夹角-45°～-40°、行星架初始角位移40°～50°、喷肥针尖与行星轮轴心距离280～300mm，此时椭圆齿轮长半轴29.364mm、齿数23、短半轴与长半轴比0.958，正圆齿轮半径25mm。

The major semiaxis a and p of the relative orbital motion are known.

我们知道其相对轨道运动的主要半长轴a和周期p。

Furthermore,the mathematical relationship between SS-O nodal period and orbital semimajor axis was deduce,which has been available for SS-O design.

推导出的太阳同步轨道交点周期与轨道半长轴的关系式已成功应用于某课题的太阳同步轨道设计中。

A cluster of formation flying satellites consists of a central satellite and several companion satellites with dense distribution and equal orbital semimajor axis.

如果轨道半长轴相等，密集分布的卫星将组成伴随卫星群。若干颗伴随卫星将在环绕中心卫星的相对伴随轨道上做周期性相对轨道运动。

Several models are advanced in this dissertation, such as precision model with Kepler orbit and approximate models with conditions in the proper order of small orbital noncoplanarity, small eccentricity, short distance, short running time and equal orbital semimajor axis.

采用逐步递进的方式，推导了一系列对应Kepler轨道的精确表达式和对应小轨道非共面度、小轨道偏心率、近距离、短时间、相等的轨道半长轴等条件的近似表达式，以适合各种情形下对航天器相对轨道运动的描述。

The program will calculate the length of the semiminor axis and the current, the minimal and the maximal distance from the Sun.

程序将会计算出半长轴的长度以及距离太阳的当前的、最大和最小的距离值。

Because of the secular perturbation variations of the ascending node right ascension, the argument of perigee and the mean angle caused by the initial deviations of the semi-major axis, the inclination and the eccentricity are linear time-variant, then the active biases of the semi-major axis, the inclination and the eccentricity can realized the self-stabilization design of the elliptical orbit satellite constellation, and so the configuration stability will be improved.

通过初始偏差对椭圆轨道卫星的长期影响分析可知，轨道半长轴、倾角和偏心率的初始偏差对升交点赤经、近地点幅角和平近点角的长期摄动变化是线性的，因此通过主动偏置轨道半长轴、偏心率和倾角能够实现椭圆轨道星座构型的自稳定设计，从而提高其构型稳定性。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。