Abstract: Apparatus and method for isolating and blocking articles flushed down toilets before they can get into and jam a main sewer line utilizes a threaded rod having a head for rotation thereof disposed on one end, a nut threaded onto the rod, a flat washer disposed next to the nut on the opposite side therefrom from the head, and a rubber washer disposed next to the flat washer on the opposite side therefrom from the nut. In a preferred embodiment, the rod is threaded into a threaded hole in a cleanout plug adjacent a toilet to be isolated and the nut tightens against the cleanout plug to compress the rubber washer to seal in sewer gases and fluids.

Abstract: Apparatus for aiding a person in walking up andn down a staircase which has at least one railing running alongside. The apparatus includes a series of structures which are affixed to the at least one railing for supporting a person's hands and arms and, thereby, a portion of the person's weight.

Abstract: Method for altering an electrical characteristic of a circuit having at least one junction formed from a first and a second semiconductor material involves applying at least one pulse --a voltage pulse, a current pulse, an energy pulse, or a power pulse and so forth-- across the junction, the pulse having sufficient amplitude of one or more of its electrical parameters and time duration to alter the electrical characteristics of the junction, and thereby, the electrical characteristic of the circuit. The pulse is applied across the junction by applying it to at least one terminal or electrode which is contacted to the first or second semiconductor material. In addition, the amplitudes of the electrical parameters and time duration of the at least one pulse should be low enough to ensure that dendrites or filaments of material from the at least one electrode, for example, metal, are not formed in the first or second semiconductor material.

Abstract: Circuitry which permits a plurality of peripherals to share a single interrupt signal line in computer systems and thereby increase the number of peripherals which can be supported.

Abstract: Apparatus which removably attaches to a station such as a computer terminal to display and hold materials such as papers, notes and so forth from the right and left side of the computer terminal and to display paper which hangs down from the apparatus and/or which stands up from the apparatus. The holder includes: (1) a head section having first and second flaps attached by hinges to opposite ends of a middle section and having Velcro on one side for removably attaching them to surfaces; (2) a T-section attached by a hinge to a side of the middle section; and (3) a T-insert section which is removably interlockable with the T-section. The T-section and the T-insert section together provide means for removably holding papers and other materials.

Abstract: The present invention relates to an apparatus for laser isotope detection and concentration measurement (LIDAM). A test sample containing first and second isotopes of a specific material or compounds formed with the first and second isotopes of the specific material is placed in an optical bridge with a standard sample containing known amounts of the first and second isotopes or compounds of the same. Laser radiation from a first and a second laser source is alternatively focused upon the two samples to produce fluorescence from the isotopes or compounds of the specific material. The laser material of the first laser source and the laser material of the second laser source are either the first and the second isotope respectively or compounds formed with the first and the second isotope respectively. Laser radiation from the first and the second laser source induces fluorescence only from the first and second isotope or compounds of the same in either the test or standard sample.

Abstract: A display cell having at least two states of different opacity, comprises a first material having a first index of refraction, a second material dispersed within the first material and having a second index of refraction, the difference between the first and the second indices of refraction being variable over a range of values, and means for varying the difference in index of refraction over a portion of the range. When the indices of refraction of the first and second material are substantially the same, the display is substantially transparent. Otherwise it is opaque or substantially less transparent.

Abstract: In order to prevent drift between the two stable states in the bulk of the liquid crystal material, a specific cell isolation region formed from the same liquid crystal material is required. This cell isolation is provided in one embodiment by a uniformly tilted liquid crystal alignment. The surface of the substrates between which the liquid crystal material is disposed is treated to provide the uniform tilt in regions which surround the bistable volumes of liquid crystal material.

Abstract: Tunable laser radiation is obtained by pumping a wedge-shaped ultra-short laser cavity with picosecond excitation pulses. Continuous tuning of the laser is achieved by translating either the wedge-shaped laser cavity or the excitation pulses so that different volumes of the laser material are exposed to the excitation pulses. In one embodiment utilizing picosecond laser excitation pulses the wedge-shaped laser cavity is a slightly wedged film of GaAs coated on both sides with dielectric mirrors.

Abstract: The present invention comprises an apparatus which provides a combination of excitation pulses or a signle shaped excitation pulse to a plasma-recombination laser which both creates the plasma and controls the electron-ion collisional recombination rate therein. The application of the single shaped excitation pulse or combination of excitation pulses keeps the electron temperature of the plasma at a temperature unfavorable to recombination until the electron density has fallen into the optimum range for laser action. The termination of the excitation pulse or pulses results in immediate laser action having power at least several orders of magnitude over that achieved in the prior art.

Abstract: Broadband laser gain is obtained in semiconductor materials by pumping an ultra-short laser cavity with picosecond excitation pulses. The broadband laser gain is used to provide picosecond laser radiation energy covering a wide spectrum of frequencies.

Abstract: An efficient recombination laser comprises a resonant laser cavity, a gaseous laser material disposed in the cavity, and means for providing a plasma discharge in said laser material, which plasma discharge is confined to a cylindrical region along the axis of the laser cavity. The plasma in the gaseous laser material expands outward radially from the cylindrical region at the axis of the cavity and cools by interacting with the adjacent unexcited gas. The maximum laser gain is provided in an annular region, which annular region is adjacent to and surrounds the initial discharge cylindrical region. In one embodiment of the present invention, the means for providing the plasma discharge comprises two pin-type electrodes which extend into the cavity along the cavity axis.

Abstract: An apparatus utilizing four-wave degenerate mixing detects birefringence in irregularly shaped objects (6). Laser radiation (120) having a specified polarization is brought to a focus and then sent through the irregularly shaped object. The emerging radiation impinges upon a nonlinear material (8) to form a conjugate beam by means of four-wave degenerate mixing. The conjugate beam, which passes back through the object, is picked off and detected at a replica of the focus point. The detector (10, 11 and 12) includes a polarization detector (10) which is arranged so that a signal is detected only when the object has birefringence.

Abstract: A high-voltage, high current pulse is applied to a series of two or more conducting strips (101-110) installed in series in a laser cavity (150-151) containing either a buffer gas or a vacuum. The strips are separated by small gaps. When the high-voltage, high-current pulse is applied to the strips, plasmas (141-149) are formed in the gap regions. The plasmas are comprised of ions from the strip material. Once formed, these plasmas expand hemispherically, cool and recombine to provide laser action. The composition of the plasmas depends on the strip material, the electric field in the gaps, the gap size and the background gas type and pressure.

Abstract: A laser apparatus for inverting a population in an atomic or molecular species is provided. Energy is stored in a first species and a laser induced collisional energy transfer from that first species to a selected dissociative molecular state of a second species causes an inversion of one of the constituents of the second species. This is represented, in one embodiment of the present invention which utilizes a second species comprising a diatomic molecule, by the reactionA*+BC+h.nu..fwdarw.A+(BC)*.fwdarw.A+B*+C,where A and A* are the ground and excited states of the first species respectively, denoted as the storage species, BC and (BC)* are the ground and excited states of the second species respectively, which comprises atoms B and C, and B* is the excited state of atom B, which excited state is inverted.

Abstract: A liquid crystal cell having memory is provided by disposing a liquid crystal material having nematic directors between two substrates which are fabricated to contain an array of singular points. The cell may further include means for detaching singularities such as appropriate electrode arrangements.These substrate configurations provide multistable configurations of the director alignments because disclinations must be moved, either through the bulk of the liquid crystal material or on the substrate surfaces to switch between the stable configurations.The switching of the device between stable configurations may be accomplished by the application of electrical fields to the liquid crystal material.The stable configurations may be optically differentiated by the incorporation of pleochroic dyes into the liquid crystal material or by crossed polarizers.

Abstract: The invention relates to a variable attenuator having two phase gratings (1 and 2) with rectangular grooves. In a first embodiment of the present invention the gratings are slidably mounted (10, 20, 30) so that the gratings have the grooves parallel and the faces in close proximity. As one grating is translated relative to the other the light passing through the device may be varied from total extinction to substantially total transmittance. A single device can be fabricated to provide this attenuation for radiation spanning the visible spectrum. In other embodiments the gratings are fixed relative to one another and the entire device is moved relative to the beam to be attenuated.

Abstract: A cw laser beam of radiation superimposed upon a beam of particles, for example a beam of neutral particles, can cause substantial changes in particle trajectories when the radiation frequency is tuned near a resonant transition in the particle. The particles can be confined by, ejected from, or steered by the laser beam. The present invention teaches the range of values over which the frequency of electromagnetic radiation is to be offset from the frequency of a particle resonance, as a function of radiation power for specific wave propagation modes, to produce best focusing of the particle beam by a copropagating beam of electromagnetic radiation. Our invention takes into account the effect of random fluctuations which arise out of the quantum nature of the electromagnetic wave-particle interaction in order to determine the appropriate range of values.

Abstract: The successful application of the reactive ion etching technique to the III-V compounds requires the use of the appropriate etch gas. We have found that a gas mixture comprised of either CCl.sub.2 F.sub.2 alone or in combination with one or more of the gasses: argon (Ar), oxygen (O.sub.2) and nitrogen (N.sub.2) will cleanly and effectively etch GaAs and InP and their ternary and quaternary alloys as well as AlGaAs and the oxides of GaAs. The effective ranges of relative flow rates of Ar, CCl.sub.2 F.sub.2 and oxygen are: Ar (0-83%), CCl.sub.2 F.sub.2 (8-100%), O.sub.2 (0-50%), and N.sub.2 (0-60%).

Abstract: Grating resonators for surface acoustic waves or surface optical waves are coupled in cascade via a track changer external to the resonator cavities. At least one grating of each resonator is partially transmissive in the resonant band, allowing the interchange of energy therebetween via the track changer. The track changer is comprised of either two or three reflective racks angled such that the energy reflected therein propagates along zero-temperature-coefficient paths. The three-rack, three-bounce U-path filter used as a track changer minimizes resonant energy losses due to variations in reflected wave angles from their designed values.