Abstract: Polyimides with enhanced electrical conductivity are produced by adding a silver ion-containing additive to the polyamic acid resin formed by the condensation of an aromatic dianhydride with an aromatic diamine. After thermal treatment the resulting polyimides had surface conductivities in the range of 1.7.times.10.sup.-3 4.5 .OMEGA..sup.-1 making them useful in low the electronics industry as flexible, electrically conductive polymeric films and coatings.

Abstract: A gallium-indium-zinc-copper metallic material has been found to exhibit many of the advantageous properties of mercury, such as electrical conductivity, fluidity, and high vaporization temperature. The metallic material is formulated by combining individual components in the presence of aqueous base, isolating the metallic phase, and heating the metallic combination. The metallic material is formulated to have sufficient quantities of each of the individual components such that the metallic material has a solidification temperature below 0.degree. C.

Abstract: Disclosed is a thermally-stable SnO.sub.2 -surfaced polyimide film wherein the electrical conductivity of the SnO.sub.2 surface is within the range of about 3.0.times.10.sup.-3 to about 1.times.10.sup.-2 ohms.sup.-1,. Also disclosed is a method of preparing this film from a solution containing a polyamic acid and SnCl.sub.4 (DMSO).sub.2.

Abstract: Liquid gallium or gallium alloy is utilized as the conductive fluid in a switch or sensor housing. In order to prevent wetting of the interior walls of the switch or sensor housing, the liquid gallium or gallium alloy is either free of metal oxides or has only very low quantities of metal oxides.

Abstract: With proper handling, Gallium-Indium-Tin eutectics are suitable for use as a substitute for mercury in switch applications. The eutectics should be acid washed to prevent oxidation of the metal components of the eutectic while in the switch housing and, further, the switch housing should be filled with an inert gas. Preventing oxidation ensures long term performance of the switch. In addition, provisions need to be made to prevent wetting of the switch housing by the eutectic. Experiments have shown that acid washing of metallic switch housings prior to adding the Gallium-Indium-Tin eutectic reduces or eliminates wetting by the eutectic. In addition, experiments have shown that coating the walls of the switch housing with a fluoropolymer coating prevents wetting by the eutectic.

Abstract: A train communication and control system is described having the cars of the train connected by a two-wire train line running continuously from car to car. Any car may be selected to be a master unit. The selection of one car as a master unit disconnects the power sources of all other cars from the train line, leaving the master unit power source as the sole power source for the line. The master unit communicates with each other car by causing a high voltage ("mark" state or logic one) or a low voltage ("space" state or logic zero) to be on the train line. Each non-master car can receive a communication from the master unit, or can transmit to another car by applying a low impendance across the train line to change from a "mark" state to a "space" state. The power source consists of a voltage regulator with precision constant current limit.

Abstract: Electrical joint compounds for the protection of electrical connections are formed from a solution of polymer dissolved in solvent with or without conductive filler. Partially cured thermosetting polymers are preferred as they flow under service conditions to better seal the electrical joints. Thermosetting polymers which cure by an addition mechanism are preferred over those which cure by condensation, and polyimides are most preferred.

Abstract: In a display where all characters are displayed in equal sized spaces, such as a bus or vehicle sign, for example, the problem of characters appearing to merge from a distance is remedied. The spacing between characters is automatically adjusted in accordance with both the characteristics of the particular character representations displayed and their sequence within the display.

Abstract: A zero dead volume (ZDV) microbore high performance liquid chromatography (.mu.HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a .mu.HPLC column end fitting to minimize the transfer volume of the effluents exiting the .mu.HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF.sub.2), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells.

Abstract: A memory transfer unit is provided which permits replacing messages stored in a message display system with a different set of messages stored in the memory transfer unit. A circuit is provided for supplying power from the message display system to the memory transfer unit and for inhibiting operation of the memory transfer unit unless the power supply to it has a proper operating voltage level. Pulses produced in the message display system are counted to determine the sequential locations of data in the memory transfer unit to be transferred to the message display unit for substitution for data stored in the message display unit.

Abstract: This invention relates to improved lightweight, high temperature resistent, electrically conductive, palladium containing, polyimide films and methods of preparing same for use in aerodynamic and space application. A palladium (II) ion-containing polyamic acid solution is prepared by reacting an aromatic dianhydride with an equimolar quantity of a palladium II ion-containing salt or complex and the reactant product is cast as a thin film onto a surface and cured at approximately 300.degree. C. to produce a flexible electrically conductive cyclic palladium containing polyimide. The source of palladium ions is selected from the group of palladium II compounds consisting of LiPdCl.sub.4, Pd[S(CH.sub.3).sub.2 ].sub.2 Cl.sub.2,Na.sub.2 PdCl.sub.4, and PdCl.sub.2.

Abstract: A method for preparing an aluminum ion-filled polyimide adhesive wherein a meta-oriented aromatic diamine is reacted with an aromatic dianhydride and an aluminum compound in the presence of a water or lower alkanol miscible ether solvent to produce an intermediate polyamic acid; and thereafter converting the polyamic acid to the thermally stable, metal ion-filled polyimide by heating in the temperature range of 300.degree. C. to produce a flexible, high temperature adhesive.