Records, high-fidelity

Quality of the DOE is crucial for the recording of high-fidelity patterns, especially when phase control is involved. It can be evaluated using shear-interferometry by combining the front- and back-reflected beams on a CCD... 

High-fidelity recording especially for the inscription of numerous holograms with low diffraction efficiencies, the material must respond precisely to the light fluence during inscription. 

Other lead stabilizers are of much more specific applications. For example, dibasic lead phthalate, which is an excellent heat stabilizer, is used in heat-resistant insulation compounds (e.g., in 150°C wire), in high-fidelity gramophone records, in PVC coatings for steel, and in expanded PVC formulation. 

For human application, linear flow rates up to 200 L/min should he recordable with fidehty. The resistance to breathing depends upon the flow rate, and it is difhcult to establish an upper limit of tolerable resistance. Silverman and Whittenberger (1950) stated that a resistance of 6 mm HjO is perceptible to human subjects. Many of the high-fidelity pneumotachographs offer 5-10 mm HjO resistance at 100 and 200 L/min. It would appear that such resistances are acceptable in practice. 

The introduction of high-fidelity, stereo mierogroove 33-1/3 LPs, and 45s meant more durable, better sounding reeords could be made cheaply. The adoption of magnetic audio tape and multi-track recording by both movie and record companies made it easier to produce music for either medium. 

In cavity-compression molding the cold powder or mold material is placed under pressure in a heated mold. The process is also called hot pressing. Glass-fiber-reinforced, unsaturated polyester resins are processed by the heated-cavity-compression molding method. The vulcanization of rubber can also be carried out using this method. High-fidelity records are pressed out of the thermoplasts PVC or poly(ethylene-co-vinyl acetate), while cheaper records are injection molded. 

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