球面

In this paper we define the concept of Projective Blaschke manifolds and extend the theory of equiaffine differential geometry to the projective Blaschke manifolds. We prved that if M be a complete projective Blaschke n-sphere and its universal covering manifold is isometric to a complete (n+1) dimensional parabolic, elliptic or hyperbolic affine hypersphere, then M is a quotient space of E^n, S^n or D^n by a isometric subgroup of its corresponding spaces.

在这篇文章中我们定义了射影Blaschke流形的概念，将等仿射微分几何的理论推广到了射影Blaschke流形，并证明：如果n维完备射影Blaschke 超球面 M 的通用覆盖流形分别是完备的抛物型、椭圆型或双曲型仿射球，则M分别是n维欧氏空间、n维超球面或n维单位圆盘关于各自空间的一个等距离散子群的商，从而对完备射影Blaschke 超球面进行了分类。

Sphere Grid System, Hexagonal Grid, Address Coding, Sphere Spatial Entity, Sphere Grid Indexing

球面网格系统；六边形网格；地址编码；球面空间实体；球面网格索引

On the product of unit spheres,we give a kind of natural embeddings from the product unit spheres to the unit sphere in which the product of unit spheres can be viewed as a hypersurface.

第一个是在乘积单位球面上，我们给出自然的由乘积单位球面到高一维球面的嵌入映射，然后考虑了在乘积单位球面上预给定Gauss-Kronecker曲率后，我们所考虑的嵌入的存在性。

The phase anomaly zones are investigated on the basis of the integral theorem of Helmholtz and Kirchhoff in terms of the Kirchhoff′s boundary conditions and the physical meaning of the integral for the diverging and converging spherical waves.

从波动方程出发，在基尔霍夫边界条件下，根据积分的物理意义，简明地研究了发散和汇聚球面波的相奇异区域分布。结果表明，除了汇聚的球面波焦点区域存在相奇异现象外，焦点以外的区域及对发散的球面波同样存在相奇异现象。

Under the fixed and clamped boundary conditions, a nonlinear differential oscillation equation with quadric and cubic items was presented by the Galerkin method, and a nonlinear free oscillation equation of the shallow reticulated shells with damage was solved.

基于Lematire等效应变损伤原理，计及扁球面网壳各个杆件的损伤影响，根据薄壳非线性动力学理论推导出含有损伤扁球面网壳非线性动力学方程和协调方程，在固定夹紧边界条件下，用Galerkin方法得到一个含二次和三次非线性振动微分方程，并对具有损伤扁球面网壳的非线性自由振动方程求解。

Insert ball bearing units is composed of outer spherical ball bearing and pillow block.

各类型带座外球面球轴承由外球面球轴承和外球面轴承座组成。

In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.

这章具体研究了基于三种极化散射特性描述的相应的目标识别方法：①基于极化参数平面描述的目标识别方法，将目标回波极化状态投影到以极化椭圆参数，即椭圆率角ε和倾角τ表征的极化状态平面上，参数随观测频率的变化就形成了图，根据图的变化特点构造了目标的多维极化特征空间，并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构；②基于Poincare极化球面描述的目标识别方法，采用Stokes矢量表征目标回波的极化状态，并将其投影到描述极化状态的Poincare极化球面上，定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息，提取了准方位不变性的目标极化特征，最后设计了目标的识别器结构；③基于频率敏感性描述的目标识别方法，通过在Poincare极化球面上所定义的极化状态距离的概念，研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题，获得了在极化状态距离下的频率分布特性曲线，采用最小二乘估计曲线拟合方法，它既用于极化特征的降维，同时又直接将拟合参数作为目标的分类特征。

The formula for area of ellipsoidal triangle on earth ellipsoid by means of geodesic coordinate is derived in this paper. It is showed that the primary term is identical with the formula for area of plane triangle by planimetric rectangular coordinate in three angular point, while the expression of remainder terms has also regularity of its form. The presented formula can be applicable also to convex polygon on earth ellipsoid.

本文推导出用三顶点的测地坐标计算地球椭球面上三角形面积的公式，公式表明，其主项的表示式与按平面坐标求面积的计算式完全一致，而附加项的表示式亦有规律可循，因此该公式的适用范围可由椭球面三角形推广至椭球面上任意凸多边形。

Retrace error of nonnull aspheric testing is analyzed in detail with conclusions that retrace error has much to do with the aperture, relative aperture and surface shape error of the apsheric under test.

分析了非球面非零位检测系统中的回程误差问题，得出了回程误差与被测非球面口径、相对口径以及非球面本身面形误差均紧密相关的结论。

After some experimental results obtained in machining samples with complex ruled surface, concave spherical surface, convex surface and samples with both concave and convex surface are analyzed, the value of these samples in practical prodúction is discussed.

通过对一些典型的复杂直纹曲面样件以及凹球面、凸球面和凸凹复合球面样件加工实验分析，探讨了这些样件在实际生产中的应用价值。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。