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Base on the special characters of off-axis spherical and three-axis ion beam figuring (IBF) system, a method of obtaining the removal function depending on incidence angles are introduced and the curve be indicated. Keeping the fabrication coordinate coincident to the optical coordinate can avoid the transformation of interferometry map, which could introduce the distortion error. By analyzing of the process of polishing the 562mm×290mm off-axis mirror, the polishing experimentation has been carried out on the IBF2000 system developed by NTG. After two iterations and 37.2 hours polishing time, the RMS value of surface accuracy is from 0.033λ to 0.016λ, and the mid-spatial error mitigated dramatically. The experimentation indicates that using the non-contacting polishing feature of IBF with reasonable optimizing process, the surface accuracy and the mid-spatial error can be improved simultaneously.

By using the method of computer modeling with Matlab to compute the coordinate values of discrete points of the ideal collimating lens,the parameters of cylindrical lens are solved through the method of numerical fitting and quadric surface approximation,which simplifies the design process of laser diode beam collimated by cylindrical lens and facilitates the actual operation.The analysis result shows that the cylindrical lens with quadric surface are very suitable for collimating laser diode beam,and whose surface can be selected by actual requirements.By contrast,this method is simple,and it can easily be designed,and which can quickly adjusts the parameters to optimize.At the same time,the parameters of collimating lens can be properly selected by the grade of difficulty level in the manufacture process.

Minimum variance (MV) adaptive beamforming has been applied in medical ultrasound imaging to improve lateral resolution, but standard MV method is quite sensitive to the perturbation of the received signal. Due to the inhomogeneity of human tissues, sound speed varies and there exists a certain amount of time-delay error for each channel which is referred to as phase aberration. A robust minimum variance adaptive beamforming method was proposed in order to avoid significant degradation under more practical circumstances. The sample covariance matrix was reconstructed with a forward-backward method. And the steering vector was estimated via maximizing the output beamformer power, which was turned into a quadratic convex optimization problem with proper constraints. The simulations with Field II showed that the proposed method was robust in the presence of phase aberration and could maintain its performance for improving imaging quality.

Synthetic aperture sequential beamforming (SASB) is a two-stage delay-and-sum beamforming procedure, which can be applied to B-mode imaging with an implementation of low complexity compared to the traditional synthetic transmit aperture imaging. A new SASB imaging scheme in order to compensate the effects of axial motion is proposed. The velocity and direction of the motion can be evaluated by cross-correlation between specific beams according to adjacent focus of the SASB. The performance assessment, conducted by using simulated data, reveals that the proposed method can correct the positions of tissue motion without extra firings.

为了满足空间同轴三反相机对大口径凸非球面高精度的面形质量和精确的几何参数控制要求，提出以计算机控制确定性研抛工艺为核心的多工序组合加工及检测技术。在加工阶段，首先利用超声振动磨削技术对非球面进行面形铣磨，其次应用机器人对非球面面形进行快速研磨和粗抛，最后采用离子束修形技术实现非球面的高精度加工；在检测阶段，首先利用三坐标测量机对铣磨和研磨过程中非球面的面形及几何参数进行控制，进入干涉仪测量范围后，再采用Hindle球法对非球面光学参数进行干涉检测。结合工程实例，对一口径520 mm的凸双曲面次镜进行了加工及检测，其面形精度RMS为0.015（=632.8 nm），几何参数控制精度△R误差为0.1 mm、△K优于0.1%，满足光学设计技术指标要求。

Metal is an early telescope mirror material, it was later replaced by glass which has lower thermal expansion coefficient. However, for observing the sun, these glass materials in the primary mirror are affected by the sun's intense radiation, its temperature rises rapidly, but which conducts heat slowly. The temperature difference between mirror and ambient air is so large that causing the air turbulence which has affected the observation precision. While the metal material has better thermal conductivity characteristics, it can greatly improve the problems caused by air turbulence. This paper analyzes the characteristics of the various mirror materials, and then makes a rust-proof aluminum alloy 5A05 as the mirror substrate material. For the major deficiencies of the soft aluminum surface which is not suitable for polishing, this paper presents a method of electroless nickel plating to improve its surface properties. After the mirror go through a thermal shock, the upper and lower levels of metal CTE don’t match with each other, which leads to mirror deformation and warping. The bimetallic effect has been illustrated by the theory of beam element and give a result of elementary approximated. The analysis shows that the displacement deformation of the upper and lower layers of metal which is caused by thermal shock is smaller when the CTE is closer. In the experiments, a spherical aluminum mirrors with the substrate of 5A05 aluminum alloy, diameter of 110mm, the radius of curvature of 258.672mm is manufactured in classical technique. And it ultimately achieves optical mirror-polished precision. Besides, the long-term thermal stability experimental study of the aluminum mirrors proved that Al-infrared solar telescope primary mirror meets the needs of the long-term observation during use.

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