Abstract: The present invention provides a color concentrate comprising (a) at least one resin selected from the group consisting of a polymer of a diene, a rosin material, a coumarone-indene resin, a polymer of vinyl aromatic monomer having an M n of from about 500 to about 4000, a wax and a mixture of two or more thereof, (b) at least one resin selected from the group consisting of a copolymer of an olefin and an acrylate or a methacrylate, a polymer of a vinyl aromatic monomer having an M n of at least about 10,000 and a mixture thereof, and (c) at least one colorant.

Abstract: A compact scanned antenna which includes a radiator, a rotatable tube and a line source. The radiator is formed by plating a shaped dielectric core. It generates an antenna beam at an output aperture in response to a microwave signal at an input port. The line source generates a radiation sheet which is directed across a signal plane to the input pot. The tube has a cylindrical wall which is positioned across the signal plane. As the tube rotates, refractive or diffractive transmission structures pass through the signal plane. The refractive structures include linear segments which refract the wavefront of the radiation sheet. Because the wavefront slope at the radiator's aperture is a function of the wavefront slope at its input port, the antenna beam is scanned. The linear contour segments have the same inclination but are not colinear. This arrangement reduces the thickness of the tube wall. Phase coherence is achieved by an appropriate radial spacing of adjacent ends of contour segments.

Abstract: An antenna system includes a set of symmetrically located center-fed and segmented dipole antennas embedded on top of a frequency selective photonic bandgap crystal. A two-dimensional array of microelectromechanical (MEM) transmission line switches is incorporated into the dipole antennas to connect the segments thereof. An MEM switch is located at the intersection between any two adjacent segments of the antenna arm. The segments can be connected (disconnected) by operating the switch in the closed (open) position. Appropriate manipulation or programming of the MEM switches will change the radiation pattern, scanning properties and resonance frequency of the antenna array. In addition, an MEM switch is inserted into the crystal to occupy a lattice site in the 3-dimensional crystal lattice.

Abstract: This invention relates to an abrasive composition comprising (a) a major amount of at least one abrasive powder, (b) at least one resin selected from the group consisting of a polymer of a diene, a rosin material, a coumarone-indene resin, and a mixture of two or more thereof, and (c) at least one copolymer of an olefin and an acrylate or a methacrylate. The abrasive composition may additionally include (d) a surface active agent. The abrasive composition may be added to a polymer or resin to form purge compositions. The invention also relates to methods of cleaning processing equipment and preparing the abrasive compositions and purge composition.

Abstract: This invention relates to abrasive compositions useful in preparing purge compositions for purging plastics processing equipment comprising: (A-1) at least one abrasive powder comprising a major amount of calcium carbonate; (A-2) at least one organic rosin material; and (A-3) at least one surfactant. The abrasive compositions of the present invention further may comprise at least one viscosity reducing organic diluent. The purging compositions of the present invention comprise (A) a minor amount of the abrasive composition of the invention, and (B) a major amount of at least one polymer or resin. These purging compositions allow fast and effective purging of processing equipment. These compositions may also be reused, i.e., used for more than one purging operation, and they may be recycled by incorporating the used purge composition into a polymer which is identical to or compatible with the polymer (B) of the purge composition.

Abstract: Liquid concentrates for incorporation into polymeric resins are described that are storage stable and resistant to settling or viscosity changes which comprise:(I) a vehicle comprising:(A) at least one organic rosin material;(B) at least one surfactant; and(II) at least one colorant or additive.The liquid concentrates of the present invention have a body or consistency that allow them to readily flow by gravity and are further characterized by a substantially uniform viscosity. The liquid color concentrates of the present invention also are compatible with a wide variety of plastics and facilitate a reduction in processing deficiencies such as screw-slippage, water carry-over and uneven flow to the pump inlet.

Abstract: Liquid concentrates for incorporation into polymeric resins are described that are storage stable and resistant to settling or viscosity changes which comprise:(I) a vehicle comprising:(A) at least one organic rosin material;(B) at least one surfactant; and(II) at least one colrant or additive.The liquid concentrates of the present invention have a body or consistency that allow them to readily flow by gravity and are further characterized by a substantially uniform viscosity. The liquid color concentrates of the present invention also are compatible with a wide variety of plastics and facilitate a reduction in processing deficiencies such as screw-slippage, water carry-over and uneven flow to the pump inlet.

Abstract: A laser apparatus (10) has a coherent master oscillator radiation source (30) for driving a plurality of laser gain elements (20) positioned in a operationally parallel configuration so as to receive unamplified radiation (40) from master oscillator (30) and transmitting amplified radiation (44). Input means (60) couples portion of radiation (40) from master oscillator to each of said gain elements (20). Phase conjugate reflector means (80) operatively coupled to gain elements (20) reflects the phase conjugate of amplified radiation (44) back into the gain elements (20) where it is further amplified. Output coupling means (90) couples amplified radiation from the plurality of gain elements (20) out of the laser apparatus as a single coherent output beam of radiation.

Abstract: An imaging apparatus which permits the use of a transverse electrode electro-optic tunable filter (TEOTF), despite its obscured aperture, to produce a high quality image. The imaging apparatus includes a suitable conventional anamorphic input optical system in combination with a stacked plurality of TEOTFs in which the platelet of each TEOTF is made of an electro-optic material of a known index of refraction (such as CdS of an index of .about.2.4), and is clad between its surface and its electrodes with a material having a lower index of refraction than the platelet material (such as SiO.sub.2 of an index of .about.1.5).

Abstract: Apparatus is provided comprising a laser source, collimating optics for collimating light provided by the laser source, focusing optics for focusing the collimated light provided by the collimating optics, and a detector array disposed at the focal plane of the focusing optics. Two surface acoustic wave transducers are disposed adjacent to one another and adjacent to an optical path between the collimating and focusing optics. The surface acoustic wave transducers are individually connected to antennas which are oriented substantially parallel to one another. The surface acoustic wave transducers launch surface acoustic waves which interact with the laser light and cause the light to be deflected in proportion to the amplitude and frequency of signals applied to the surface acoustic wave transducers by the antennas. The beams deflected by the two surface acoustic waves result in an interference pattern created at the detector array.

Abstract: Apparatus for coding a laser beam to provide guidance signals, or the like. In the transmitter, the laser beam traverses two modulators to provide two-dimensional encoding. In the receiver, the detected signals are amplified, frequency-discriminated, and mixed to form guidance signals. The modulator is a modified Stark cell wherein four split longitudinal planar electrodes allow for beam encloding as a function of two frequencies by the process of molecular absorption. Bias and modulating signals applied to the electrodes interact with the molecular absorbing gas and with the beam to encode position information as a function of the specific frequencies. The amplitude of the first encoding frequency varies from a maximum at one edge of the beam, decreasing to a minimum at the opposite edge, and vice versa for the second encoding frequency. The amplitudes of both are equal on beam center.

Abstract: Electronically tunable optical filters are disclosed wherein a spatially varying dc electric field is applied to successive regions of a birefringent crystalline medium disposed between a pair of suitably oriented polarizers along the path of a light beam to be filtered. The dc electric field, which may be either parallel or perpendicular to the light path, electro-optically produces in the birefringent medium an effective oscillation of the optic axis of the medium about the pass direction of the input polarizer in a plane perpendicular to the light path as a function of distance along the light path with a predetermined spatial variation to achieve a desired filter transmission characteristic. The electric field is generated from programmable control voltages to provide a wide variety of filter passband or stopband characteristics.

Abstract: A beam of ammonia molecules including the isotopes N.sup.15 H.sub.3 and N.sup.14 H.sub.3 is generated wherein some of the molecules of each isotope reside in an asymmetric energy state and other of the molecules of each isotope reside in a symmetric energy state. The symmetric state molecules are removed from the beam in a first state selector to provide a beam containing substantially only asymmetric state molecules of each isotope. The latter beam is fed to a resonant microwave cavity where it interacts with microwaves of a frequency inducing asymmetric state to symmetric state transitions for molecules of one of the isotopes but not for molecules of the other isotope. Either the asymmetric state molecules or the symmetric state molecules are removed from the resultant beam in a second state selector to provide a beam containing substantially only molecules of the other energy state enriched in the isotope N.sup.15 H.sub.3.

Abstract: There is described a hermetic coaxial cable particularly adapted to be produced in miniature form and having a completely solid cross section with a solid metal central conductor, a tubular metal outer conductor, and a continuous glass dielectric insulator therebetween.

Abstract: A wideband optical ring modulator is disclosed. A ring resonator containing a synchronous travelling wave electro-optic modulator is disposed external to a laser cavity. The invention provides a compact lightweight optical modulator which combines the power enhancement capabilities of a resonant cavity with the wideband capabilities of a travelling wave coupling modulator. The present invention is especially useful for, although not limited to, ultra-wideband infrared laser communication systems utilizing PCM techniques.

Abstract: A laser internal coupling modulation arrangement is disclosed wherein a wire grid polarizer serves as one of the reflectors forming part of the laser optical cavity, as a polarization selector which constrains the laser oscillation to a desired linear polarization, and as an output coupler which couples an orthogonal linearly polarized beam out of the laser optical cavity in response to an amplitude varying modulating signal applied to an electrooptic modulator disposed within the laser optical cavity.

Abstract: In the disclosed parametric frequency converter a dc electric field is utilized to remove spatial inversion symmetry of NH.sub.2 D gas molecules contained in a Stark cell. Simultaneous introduction into the Stark cell of a laser beam at a frequency f.sub.1 (e.g., corresponding to about 10.6 .mu.m) and microwaves at a frequency f.sub.2 (e.g., about 4.1 GHz) produces resonantly enhanced parametric mixing of the frequencies f.sub.1 and f.sub.2, resulting in the generation of a laser beam at the difference frequency f.sub.3 = f.sub.1 - f.sub.2.

Abstract: There is disclosed a synchronous traveling wave electro-optic modulator for ultra-wideband infrared laser communications systems which provides optical waveguiding of the laser beam through an interaction distance which is large relative to the diffraction limit of the laser beam and which affords essentially perfect radio frequency and optical velocity synchronism at a relatively high electrical impedance level by appropriate choice of the design parameters of the device. The device comprises an array of very slender rectangular rods of electro-optic material such as cadmium telluride laid end to end in juxtaposition to form a light pipe for an infrared laser beam. The length to cross-section ratio of the light pipe is many times greater than that which is determined by the diffraction limit and consequently the voltage and power required to achieve a given depth of modulation is substantially reduced.

Abstract: A laser beam frequency modulation demodulator is disclosed utilizing the highly linear frequency versus voltage characteristic of the absorption resonance provided by a Stark-effect cell. An error signal, generated by dither modulation of the Stark-effect cell voltage, is fed back to the Stark-effect cell via a low-pass filter to cause the absorption resonance to track the instantaneous frequency of the laser beam. The feedback signal applied to the Stark-effect cell has an amplitude proportional to the frequency modulation on the laser beam.

Abstract: A waveguide gas laser is disclosed wherein narrow resonances in the loss vs. wavelength characteristics of a hollow waveguide laser resonator are employed to achieve wavelength selectivity. The laser includes a capillary bore waveguide of radius a and length 2L (or length L in a half-symmetric arrangement) which contains a laser gas having a laser transition capable of providing stimulated emission of light at wavelength .lambda.. The aforementioned loss resonances are achieved when the waveguide dimensions and the wavelength .lambda. are of preselected values satisfying the relation ##EQU1## where N is a positive integer.