Abstract:
Dry acrylamide is produced by reacting acrylonitrile with from 0.3 to 1 mole of water in the presence of a metallic nitrile conversion catalyst. The reaction is conducted under conditions of pressure and temperature and other reaction conditions to convert at least 30% by weight of the nitrile to acrylamide. This reaction produces a solution of acrylamide dissolved in nitrile which then is either treated by means of cooling or pressure reduction to precipitate acrylamide crystals from the reaction mixture, which crystals are then recovered.
Abstract:
A surface relief pattern, e.g. a surface relief hologram, is substantially linearly transferred to a hard durable substrate, capable of being used as a medium for permanent storage of the pattern or as a master for replicating the hologram, from a photoresist coated on the substrate, by exposing the photoresist and the substrate to a photoresist developer bath and a chemical bath capable of etching the substrate at a rate substantially proportional to the development rate of the photoresist. This technique allows the transfer of surface relief patterns with dimensions on the order of one micron or less, and is applicable to the formation of surface relief holographic patterns in permanent media for archival storage and to making master surface relief holograms.
Abstract:
A passively, Q-switched laser operating at an eye safe wavelength of between 1.2 and 1.4 microns is described. The laser may operate at a lasing wavelength of 1.34 microns and use a gain element of Nd:YVO4 and a saturable absorber element of V:YAG. The systems and methods to produce short pulses having a pulse duration less than 1 ns and high energy pulses having pulse energies greater than 2 μJ are described.
Abstract:
A frequency modulated, continuous wave (FMCW) laser using a microchip gain medium, an optical coupling element, and a tuning element is described. The laser may be part of a coherent laser ranging system.
Abstract:
The described system and method uses data from interaction between a known wave and an unknown wave to analyze or characterize the unknown wave using cross correlation frequency resolved optical gating (X-FROG). The system may obtain X-FROG trace data from the interaction between the two waves. The system analyzes the X-FROG trace data using a modified principal component generalized projection method strategy to invert the X-FROG trace data, analyzing or characterizing the unknown wave. Results of the analysis can be provided in real time and displayed.
Abstract:
Value documents or other articles having authentication features, authentication apparatuses, and methods of authentication are provided that relate to the use of taggants that absorb radiation from an illumination source and emit radiation in a manner that has a maximum intensity occurring a duration of time after the illumination source has been switched off. The taggants include a crystalline composition comprising a host crystal lattice doped with a first rare earth active ion, and in some examples a second rare earth active ion.
Abstract:
A method for providing a printed optical illusion image having first and second illusion states, comprising: receiving a specification of an optical illusion image having one or more mutable portions; and printing the optical illusion image on a printing device using a plurality of colorants, wherein one or more of the colorants are appearance mutable colorants having spectral characteristics can be switched between a first colorant state and a second colorant state by application of an appropriate external stimulus. The printed optical illusion image can be switched between the first and second illusion states by applying the appropriate external stimulus to controllably switch the one or more appearance mutable colorants between their first and second colorant states, thereby switching the mutable portions of the printed optical illusion image between corresponding first and second appearance states.
Abstract:
A method of operating a digital camera, includes providing a digital camera, the digital camera including a capture lens, an image sensor, a projector and a processor; using the projector to illuminate one or more objects with a sequence of patterns; and capturing a first sequence of digital images of the illuminated objects including the reflected patterns that have depth information. The method further includes using the processor to analyze the first sequence of digital images including the depth information to construct a second, 3D digital image of the objects; capturing a second 2D digital image of the objects and the remainder of the scene without the reflected patterns, and using the processor to combine the 2D and 3D digital images to produce a modified digital image of the illuminated objects and the remainder of the scene.
Abstract:
A method for providing a printed optical illusion image having first and second illusion states, comprising: receiving a specification of an optical illusion image having one or more mutable portions; and printing the optical illusion image on a printing device using a plurality of colorants, wherein one or more of the colorants are appearance mutable colorants having spectral characteristics can be switched between a first colorant state and a second colorant state by application of an appropriate external stimulus. The printed optical illusion image can be switched between the first and second illusion states by applying the appropriate external stimulus to controllably switch the one or more appearance mutable colorants between their first and second colorant states, thereby switching the mutable portions of the printed optical illusion image between corresponding first and second appearance states.
Abstract:
A method of operating a digital camera, includes providing a digital camera, the digital camera including a capture lens, an image sensor, a projector and a processor; using the projector to illuminate one or more objects with a sequence of patterns; and capturing a first sequence of digital images of the illuminated objects including the reflected patterns that have depth information. The method further includes using the processor to analyze the first sequence of digital images including the depth information to construct a second, 3D digital image of the objects; capturing a second 2D digital image of the objects and the remainder of the scene without the reflected patterns, and using the processor to combine the 2D and 3D digital images to produce a modified digital image of the illuminated objects and the remainder of the scene.