Powerful Laser Diode Matrixes for Active Vision Systems
— This article is deal with the experimental investigations of the laser diode matrixes (LDM) based on the AlGaAs/GaAs heterostructures (lasing wavelength 790-880 nm) to find optimal LDM parameters for active vision systems. In particular, the dependence of LDM radiation pulse power on the pulse duration and LDA active layer heating as well as the LDM radiation divergence are discussed.
Experimental study of all-weather NIR laser active imaging system
An all-weather NIR laser active imaging system with high power NIR pulse laser, image intensifier CCD (ICCD) camera and range-gated synchronization control technology is developed for acquiring longer detection range and high resolution image in adverse weather conditions. The system composition and working principle are introduced. The laboratory and outfield experiments have been done to validate imaging effect and imaging quality. The results show that the minimum resolution is about 5cm when observing the target far from 1200m in the dark of night and the image resolution could reach to 10cm when observing the target far from 2500m in misty condition. Furthermore, the minimum resolution is about 20cm when observing the target far from 4800m and the image is too blurred to accurately identify the target when observing the target far from 7200m in rainy condition. The system could be widely used in target reconnaissance, coastal patrol, search and rescue at sea, airports, ports, oil fields and forest fire prevention.
Influence of electric fields on friction electrification between metals and borosilicate glass
Abstract In a cylindrical geometry, electric fields were applied through the entire contact area between the sliding metal and the glass surface. The maximum electric charges developed on the metal were measured and plotted against the applied voltage producing the field. The metals were high-purity nickel and gold. The borosilicate glass was Pyrex, brand 7740. The experiments with nickel, which has a work function greater than that of the glass, were performed in 10 −7 mm Hg vacuum. The experiments with gold, with a work function smaller than that of glass, were carried out in air at atmospheric pressure. The results show that: 1. 1) There is both asymmetry and a reversed slope portion in the charge vs. voltage plot. 2. 2) For a certain range of reversing fields, the electric charge developed on the nickel is always negative and the charge on gold is always positive.