scholarly journals Cement Fixation ? Control System Upgrade

2013 ◽  
Author(s):  
Jessica N. Rivas
Keyword(s):  
Control System ◽  
Fixation Control

Monocular fixation in human eye movement

1967 ◽  
Vol 167 (1008) ◽  
pp. 293-315 ◽  
Keyword(s):  
Control System ◽  
Eye Movements ◽  
Reasonable Agreement ◽  
Digital Form ◽  
Lever System ◽  
Short Period ◽  
Analysis Of Results ◽  
Fixation Control ◽  
Optical Lever ◽  
Fixation Area

The monocular eye movements associated with the maintenance of fixation have been recorded using the contact lens/optical lever system. The records, in analogue form on magnetic tape, were subsequently converted to a digital form and analysed on a computer. It is found that there is reasonable agreement between the responses of the same subject on different days, Analysis of the magnitudes and preferred directions of saccades and drifts and their interrelationships show that there is an elliptical overall fixation area which is subdivided into a series of overlapping short-period fixation areas. The results indicate that saccades occurring during fixation have one of two functions, either ( a ) to recentre the retinal image on the short-period mean fixation position, or ( b ) to move the short-period fixation area, possibly to avoid retinal receptor fatigue. An organizational model of the fixation control system has been developed from the analysis of results.

A controller for safe, convenient operation of LaB6 emitters on electron-beam instruments

1983 ◽  
Vol 41 ◽  
pp. 408-409
Author(s):  
W. J. Abramson ◽  
H. W. Estry ◽  
L. F. Allard
Keyword(s):  
Electron Beam ◽  
Control System ◽  
Thermal Shock ◽  
Appropriate Care ◽  
Electron Guns ◽  
Tungsten Filaments ◽  
Order Of Magnitude ◽  
Main Components

LaB6 emitters are becoming increasingly popular as direct replacements for tungsten filaments in the electron guns of modern electron-beam instruments. These emitters offer order of magnitude increases in beam brightness, and, with appropriate care in operation, a corresponding increase in source lifetime. They are, however, an order of magnitude more expensive, and may be easily damaged (by improper vacuum conditions and thermal shock) during saturation/desaturation operations. These operations typically require several minutes of an operator's attention, which becomes tedious and subject to error, particularly since the emitter must be cooled during sample exchanges to minimize damage from random vacuum excursions. We have designed a control system for LaBg emitters which relieves the operator of the necessity for manually controlling the emitter power, minimizes the danger of accidental improper operation, and makes the use of these emitters routine on multi-user instruments.Figure 1 is a block schematic of the main components of the control system, and Figure 2 shows the control box.

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