Photographic speed determination

Photographic Speed Determination of the Amorphous and l.c.-p-methoxvcinnamate Polymers... 

The formulation used to cast the films in order to determine the photographic speed of the p-methoxycinnamate polymers was the following ... 

Over the last decade both the speed and accuracy of data acquisition and the sensitivity of the LEED experiment have been significantly improved. In most structure determination experiments the LEED patterns are displayed on a phosphor screen. LEED I-V curves are then measured by photometric or photographic means. Fast data acquisition systems have been developed that record LEED patterns with video cameras interfaced to computers and generate I-V curves during the experiment./3,4/ The sensitivity of LEED is also being greatly increased with the development of instruments that can detect single... 

Fig. 11.8 are photographs of two instruments offered by Amherst Process Instruments (API). Fig. 11.8a is the API aerosizer, a high resolution particle size analyzer for fine powders (range 0.2 - 700 pm), which is based on aerodynamics. A gas containing the entrained particles expands through a nozzle at supersonic velocities into a partial vacuum which is contained within a barrel shock envelope. The exit velocity of a particle depends on its density and size. Two laser beams, separated by a defined distance, and two photomultipliers form the measurement zone. From the velocity and the known density of the particulate solid, the aerosizer determines size, one by one, with a speed of up to 100,000 particles per second and an accuracy of better than 1 % which make this instrument rather unique. The system uses interchangeable dispersers for different types of particles and, in total (refer to Fig. 11.8a), consists of particle dispersers (A), sensor unit (B), vacuum system (not shown), and computer (C). 

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