Dark point algorithm: a new method to test periodic structures of optical instruments

2007 ◽  
Author(s):  
Debin Cai ◽  
Yu Song
2014 ◽  
Vol 941-944 ◽  
pp. 2074-2078 ◽  
Author(s):  
Sen Liu ◽  
Zhi Peng Wang ◽  
Wei Cui ◽  
Yan Dai ◽  
Dan Dan Li

Sapphire/metal soldering joints are widely needed in various optical instruments. Traditional soldering methods are expensive and time consuming, because they usually involve a sapphire surface metallization procedure and a vacuum soldering procedure. In this study, we sealed infrared sapphire windows using a novel ultrasonic soldering method in the ambient atmosphere, with Sn-Zn-Al alloy as the solder. The wetting and bonding at the sapphire/solder and solder/metal-tube interfaces were realized by ultrasound. The microstructure of the joints was revealed by means of scanning electron microscope (SEM). The gas impermeability of the samples was investigated. This new method is very simple and cost-saving. The reliability of the samples made by this new method is equal to that made by traditional method. This is the first application of the ultrasonic interfacial deposition brazing and soldering (UIDBS) method to a practical device. We hope this method to be applied to other optical devices.


2014 ◽  
Vol 136 ◽  
pp. 1-6 ◽  
Author(s):  
Dan Wu ◽  
Huimin Xie ◽  
Minjin Tang ◽  
Zhenxing Hu

2010 ◽  
Vol 110 (9) ◽  
pp. 1223-1230 ◽  
Author(s):  
Zhenxing Hu ◽  
Huimin Xie ◽  
Jian Lu ◽  
Zhanwei Liu ◽  
Qinghua Wang

1975 ◽  
Vol 26 ◽  
pp. 293-295 ◽  
Author(s):  
I. Zhongolovitch

Considering the future development and general solution of the problem under consideration and also the high precision attainable by astronomical observations, the following procedure may be the most rational approach:1. On the main tectonic plates of the Earth’s crust, powerful movable radio telescopes should be mounted at the same points where standard optical instruments are installed. There should be two stations separated by a distance of about 6 to 8000 kilometers on each plate. Thus, we obtain a fundamental polyhedron embracing the whole Earth with about 10 to 12 apexes, and with its sides represented by VLBI.


Author(s):  
C. C. Clawson ◽  
L. W. Anderson ◽  
R. A. Good

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.


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