Liquid crystals react to electric fields in strange, exciting ways. For example, when the field is sufficiently intense, a helicoidal cholesteric system transforms into a linear nematic form(1) As a result of previous...
Liquid crystals react to electric fields in strange, exciting ways. For example, when the field is sufficiently intense, a helicoidal cholesteric system transforms into a linear nematic form(1) As a result of previous experimental and theoretical work, steady state phenomenological aspects of the transformation and its dependence on material parameters are now well understood. (2,3 A study was initiated to extend observations further by considering kinetic aspects of the transition; that is, the transient behavior provoked by application of voltage as the material transforms to the nematic state, the transformation transient, and the behavior observeb when the field is removed and the sample resumes its cholesteric form, the relaxation transient.(4,5)
作者：
LEDER, LBXerox Corporation
Special Products and Systems Division Exploratory Development Laboratory Webster New York 14580
The liquid crystalline properties of cholestanyl, cholesteryl, campesteryl, sitosteryl, and stigmasteryl chlorides were studied by measuring their behavior in mixtures with cholesteryl nonanoate. Of the five chlorides...
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The liquid crystalline properties of cholestanyl, cholesteryl, campesteryl, sitosteryl, and stigmasteryl chlorides were studied by measuring their behavior in mixtures with cholesteryl nonanoate. Of the five chlorides only cholesteryl chloride shows an obvious mesophase temperature range and microscopic texture, but all of the chloride–nonanoate mixtures are cholesteric over a wide range of compositions. The decrease in effective pitch observed as theside chain is modified appears to correspond directly to the complexity of the modification. We conclude that all of the chlorides studied are liquid crystalline despite the fact that the ordinary tests for mesomorphism do not give this indication.
作者：
STAHL, WLPOTTER, RJIBM Corporation
Systems Development Laboratory Kingston New York. IBM Corporation
Thomas J. Watson Research Center Yorktown Heights New York when this work was done: he is now with Xerox Corporation Research Division Rochester New York.
An important application of fiber optics to data processing is to illuminate hole positions of punched-card reading-stations. In the IBM 59 Card Verifier, flexible incoherently oriented bundles are employed to provide...
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An important application of fiber optics to data processing is to illuminate hole positions of punched-card reading-stations. In the IBM 59 Card Verifier, flexible incoherently oriented bundles are employed to provide a reliable, efficient, and practical method of sensing holes in punched cards. A phototransistor detects the light coming through open holes and then operates a reed relay directly. In addition, a mechanical light chopper also uses fiber optical components to provide light pulses for the electronic clock to time the machine. An electronic circuit is used to latch reed relays so that the useful signal is digital, rather than the analog hole-to-no-hole light ratio.
Magnetic and superconductive random access memories contain arrays of flux storage elements or sites, each of which is intersected by two selection lines used to switch flux, and one sense line used to detect flux cha...
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Magnetic and superconductive random access memories contain arrays of flux storage elements or sites, each of which is intersected by two selection lines used to switch flux, and one sense line used to detect flux changes. The need to have three lines intersect at many storage locations produces severe alignment problems in the fabrication of high-density deposited film memories. This paper explains and analyzes a recently announced sensing technique that operates by detecting the voltage drop caused by eddy currents induced in a normal continuous metal sheet whenever the flux linking it changes. The method is found to operate at room and cryogenic temperatures, and overcomes the alignment difficulties of the sense line technique.
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