准球面

This paper reviews whether forward movement of the posterior corneal surface occurred, changes in posterior corneal power and curvature, changes in posterior corneal astigmatism and tilt, changes in posterior corneal asphericity and BFS after the surgery.

本文综述了准分子激光屈光性手术后角膜后表面是否发生前移改变、角膜后表面屈光力、曲率、散光度、轴度、非球面特性以及最适球面等是否发生改变的研究进展。

For testing the concave ellipsoidal mirror of Three Mirror Cassegrain optical system, a slab compensated auto-collimation method is suggested.

针对TMC光学系统凹椭球面主镜的检验，本文提出了一种平板补偿的自准检验方法。

The non-spherical lens is another shaping system that is used to collimate the beam of LD, and the theoretic performance could be perfect.

非球面柱透镜是另一类特殊结构的柱透镜，在用于半导体激光束准直时，理论上可以达到完全准直的效果。

By using two groups of cylindrical lenses perpendicular to each other, the marking shape window of semiconductor laser is imaged and rectangle and this imagery is then collimate d to infinite by collimating objective.

利用互相垂直的两组圆柱面镜把半导体激光器的条形窗口成像为矩形。再用球面准直物镜组把此象"准直"到"无限远"。该系统把激光器发出的发散光束压缩到在±0.0025弧度内出射光。两组柱面镜的同种倍率互为倒

The model of this collimator set on the ray trace theory. The designing and optimization way are created.

通过该方法设计的准直系统，在实际应用中达到了与传统非球面柱面镜相同的准直效果。

A standard accessorial reflecting mirror was incorporated into the beam path of an interferometer to build up a autocollimating system for measuring the aspheric wavefront aberration of paraboloidal, ellipsoidal and hyperbolic mirrors with the method of aberrationless point.

为了检测抛物面、椭球面和双曲面镜，在干涉仪工作光路中加入一个标准辅助反射镜，组成自准直系统，采用干涉法中的无像差点法实现对非球面波像差的检测。

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。

LAMOST is a meridian telescope with a fixed spherical mirror MB, an alt - azimuth mounting reflecting Schmidt corrector MA and a focal plane.

LAMOST是一架准中星仪式的望远镜，由于它的球面主镜MB是固定的，对天体的指向跟踪运动完全由MA 担任。

And this paper also shows the structure and parameters of the optical system. The Xenon light of super high voltage is used as interferential source. The position of it is on the focus of the reflector of ellipsoid surface. After reflecting, its lights form a collective point . This point and objective focus of collimation lens are superposition. Though the collimation lens, the beam of light become parallel lights. Then though the Coude Reflector and radiation system of special prism, the lights become a beam of light with 3 ° emanative angle.

该光学系统选用超高压氙灯作光源，使其位于椭球面反射镜的一个焦点上，发出的光线经椭球面反射后所形成的汇聚点与准直负透镜组的物方焦点重合，光束经准直系统后变为平行光束，此平行光束再经库德反射镜和特殊发散棱镜系统，形成具有3°发散角的发散光束，用来干扰敌方设备。

The lens axicon is based on the use of the spherical aberration of the mirror surfaces,which is inexpensive and easy to manufacture into a element with large apertures as compared with diffractive axicons,refractive cone axicons,and earlier lens axicons with aspheric surfaces;the opaque disk can offer the Bessel beams with long non-diffracting distances,and the diameter of the central peak is adjusted by choosing the focal length of the collimating lens;the tunable fluidic conical lens is a new device for generating Bessel beams,which can obtain the Bessel beams with different parameters by varying the refractive indexes of the solution which is filled in the device.

双透镜轴棱锥法主要基于透镜球面像差的运用，与衍射轴棱锥、折射轴棱锥和早期的非球面轴棱锥相比，具有加工简单、便宜，易于制作大尺寸的特点；不透明障碍物法得到的贝塞尔光束具有很长的无衍射距离，其直径可通过选择不同焦距的准直透镜来得到调节；可调流体轴棱锥是一种产生贝塞尔光束的新型器件，它可以很容易地通过改变注入器件的液体的折射率来得到不同参量的贝塞尔光束。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了