Abstract:
A new and distinctly salt and boron tolerant poplar tree cultivar named “RRR Yellow,” is particularly distinguishable by its ability to tolerate and grow in soil with high concentrations of salt, boron and selenium. The cultivar was originally discovered as a sport through stringent selection of cultivated poplar trees, and potentially from isolation of a single unique sapling or sport that exhibited high levels of salt and boron tolerance necessary for survival, and then propagated into the “RRR Yellow” cultivar.
Abstract:
Compact beam manipulators employ one or more Risley prism sets with or without a parallel plate translator. One beam manipulator contains a plate mounted to permit pitch and yaw adjustments and a prism set mounted to permit rotations. The rotations of the prisms adjust a beam direction, and adjustment of the plate adjusts the beam position. Another beam manipulator contains a prism set mounted to permit rotations and pitch and yaw adjustments of the prisms. The rotations and pitch and yaw adjustments provide coupled changes in the position and direction of a beam, and iterative adjustments alternate between rotating prisms to change the beam direction and the adjusting pitch and yaw to change the beam position. The iterative adjustments are complete when the beam has a target position and a target direction to within required tolerances. Gluing elements to optic holders minimizes stress-induced birefringence and temperature and humidity effects.
Abstract:
An apparatus and method for measuring displacement includes a light beam directed to an interferometer core that splits the light beam into first and second component beams. The first component beam is directed to a diffraction grating at approximately a Littrow angle. A diffraction is received by the interferometer core and is combined with the second component beam. The combination of the first and second component beams is measured to determine displacement of the diffraction grating.
Abstract:
A method for designing a base includes (1) selecting a location of a first center of expansion of a child part (CEchild) relative to a parent part; (2) determining a location of a second center of expansion of a bond joint (CEbond) bonding the child part to the base; and (3) determining a location of a third center of expansion of the base (CEbase) on a centerline, which is defined by the CEchild and the CEbond, so the CEchild does not substantially move relative to the parent part under a temperature change. To determine the location of the CEbase, the method further includes (a) determining a length change to the child part from the CEbond to the CEchild under the temperature change; (b) determining a length of the base that produces the same length change under the temperature change; and (c) locating the CEbase at the length away from the CEbond.
Abstract:
An apparatus and method for measuring displacement includes a light beam directed to an interferometer core that splits the light beam into first and second component beams. The first component beam is directed to a diffraction grating at approximately a Littrow angle. A diffraction is received by the interferometer core and is combined with the second component beam. The combination of the first and second component beams is measured to determine displacement of the diffraction grating.
Abstract:
A Littrow encoder is disclosed. The encoder includes first and second interferometers and a beam splitter assembly that splits a first instrument light beam into first and second interferometer input beams and directs these beams into the first and second interferometers, respectively. Each interferometer generates a measurement beam and a reference beam and directs the measurement beam toward a grating on a surface from which the measurement beam is diffracted, the measurement beam from the first interferometer striking the surface at a Littrow angle that is the negative of the angle at which the measurement beam from the second interferometers strikes that surface. Each interferometer includes at least one intensity detector that generates a signal related to an intensity of light in a combined light beam that includes the reference and measurement beams from that interferometer.
Abstract:
A Littrow encoder is disclosed. The encoder includes first and second interferometers and a beam splitter assembly that splits a first instrument light beam into first and second interferometer input beams and directs these beams into the first and second interferometers, respectively. Each interferometer generates a measurement beam and a reference beam and directs the measurement beam toward a grating on a surface from which the measurement beam is diffracted, the measurement beam from the first interferometer striking the surface at a Littrow angle that is the negative of the angle at which the measurement beam from the second interferometers strikes that surface. Each interferometer includes at least one intensity detector that generates a signal related to an intensity of light in a combined light beam that includes the reference and measurement beams from that interferometer.
Abstract:
An apparatus for manipulating a path of a beam includes a first wedge and a second wedge. The first wedge includes a first refractive surface and a second refractive surface. The second wedge includes a third refractive surface adjacent to the second refractive surface, and a reflective surface. The beam refracts at the first refractive surface, refracts at the second refractive surface, refracts at the third refractive surface, reflects from reflective surface, refracts at the third refractive surface, refracts at the second refractive surface, refracts at the first refractive surface. At least one of the first wedge and the second wedge can be rotated so that the beam exiting the apparatus can be oriented substantially orthogonal to the beam entering the apparatus.