Design of an off-axis three-mirror system with high speed for hyperspectral imagers

2008 ◽  
Author(s):  
Guangbiao Gong ◽  
Yiquan Ji ◽  
Shanbing Zhu ◽  
Ruirui Zhang ◽  
Weimin Shen
Keyword(s):  
1982 ◽  
Vol 21 (4) ◽  
pp. 589 ◽  
Author(s):  
R. H. Freeman ◽  
H. R. Garcia

2014 ◽  
Vol 568-570 ◽  
pp. 1026-1030
Author(s):  
Xue Jin Bai ◽  
Yong Ming Qiao

Fast-steering mirror system demands higher accuracy and fast responding speed to track targets, but the conventional PID controllers cannot meet the demands. Instead, the fuzzy PID control can greatly improve the capturing and tracking capacities to high-speed dynamic targets. So we apply the fuzzy-PID controller in the positioning loop of the stabilized system, not only improving the transient process of the control system and decreasing the overshoot, but also enhancing the accuracy of tracking stabilization and response. At the end, simulations were performed to test the effectiveness of this method through the MATLAB platform.


IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 38546-38553
Author(s):  
Tomoaki Mashimo ◽  
Shunsuke Izuhara ◽  
Shiro Arai ◽  
Zhong Zhang ◽  
Hiromasa Oku

2012 ◽  
Vol 18 (9-10) ◽  
pp. 1487-1496
Author(s):  
Seungho Lim ◽  
Byung-Han Ko ◽  
Kyoung-Su Park ◽  
No-Cheol Park ◽  
Young-Pil Park ◽  
...  
Keyword(s):  

1978 ◽  
Vol 48 ◽  
pp. 271-278
Author(s):  
Chr. Kühne

The PZT according to MARKOWITZ, undoubtedly one of the most accurate measuring instruments, has become an integral part of astronomy in the last years. Yet there are two reasons why I still tried to improve the MARKOWITZ basic idea.For the MARKOWITZ process the use of a lens objective is imperative. Because of the diameter limitations of the lens objectives the magnitude is reduced. Although a 65 cm PZT has been put into operation in Washington recently, the thermal difficulties encountered made it necessary to control the temperature actively. In addition, the 65 cm diameter of a lens equipped with 4 elements can be considered as the very limit, but not for a mirror system.In addition there are still more disadvantages using lens objectives. The useable field is restricted by astigmatism, reducing the range of declination. The transmission, especially in the blue wavelengths, decreases very rapidly with the thickness of lenses. For large multilens objectives the transmission is less than for a mirror system.


Author(s):  
E.D. Wolf

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.


Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.


Author(s):  
William Krakow

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.


Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.


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