Abstract: A transceiver for use in a radio transmission system has a plurality of receiving antennas and a plurality of transmitting antennas. The time delays between received antenna signals produced by a radio signal transmitted from another transceiver in the system are detected. For transmission, the time delays between the transmitted antenna signals are adjusted to correspond to the detected time delays between the received antenna signals. By antenna sharing, each may actually serve for both transmission and reception. Since the delayed transmitted signals will arrive simultaneously at the other transceiver they will superpose on each other, thus achieving a significant improvement in received signal strength at such transceiver.

Abstract: The invention relates to an addition compound which is obtainable by reaction of a diamine of the formula I, ##STR1## where R.sup.1 is (C.sub.2 -C.sub.4)-alkylene or 1,2- or 1,3-cyclo-(C.sub.3 -C.sub.7)-alkylene andR.sup.2 and R.sup.3, which are identical or different, are (C.sub.1 -C.sub.3)-alkyl or hydrogen orR.sup.2 and R.sup.3 together are (C.sub.2 -C.sub.4)-alkylene, with fullerenes C.sub.60 and/or C.sub.70. The fullerene derivatives are useful as electrically conducting materials.

Abstract: The present invention is concerned with core and shell polymeric particles having microvoids in the core and one or more channels connecting the microvoids to the exterior of the particle. These particles, or LCAPs are produced by forming a core of polymeric acid, encasing the core in a shell polymer permeable to base, and then neutralizing the core such that the core swells, causing the shell to "explode" in a controlled fashion. This controlled explosion causes channels to form in the shell.These particles can be used as control release devices for target compounds, to impart reinforcing properties to acrylic films, as an opacifying agent in coating compositions, and as a supplement or replacement of part or all of the pigmentary material or extenders that would otherwise be used in such coating compositions.

Abstract: The present invention is concerned with core and shell polymeric particles having microvoids in the core and one or more channels connecting the microvoids to the exterior of the particle. These particles, or LCAPs are produced by forming a core of polymeric acid, encasing the core in a shell polymer permeable to base, and then neutralizing the core such that the core swells, causing the shell to "explode" in a controlled fashion. This controlled explosion causes channels to form in the shell.These particles can be used as control release devices for target compounds, to impart reinforcing properties to acrylic films, as an opacifying agent in coating compositions, and as a supplement or replacement of part or all of the pigmentary material or extenders that would otherwise be used in such coating compositions.

Abstract: A method is disclosed for improving the erasability of erasable marking compositions, while maintaining the opacity of the coating and without producing burnishing, by incorporating into the compositions voided latex particles having a shell polymerized from either:(1) at least about 25% by weight, based on the weight of the shell, of a crosslinking comonomer;(2) at least about 5% by weight, based on the weight of the shell, of a crosslinking comonomer, when at least about 50% by weight of methyl methacrylate is used as a comonomer in the shell.An improved liquid marking composition is also disclosed.

Abstract: A method is disclosed for improving the erasability of erasable marking compositions, while maintaining the opacity of the coating and without producing burnishing, by incorporating into the compositions voided latex particles having a shell polymerized from either:(1) at least about 25% by weight, based on the weight of the shell, of a crosslinking comonomer;(2) at least about 5% by weight, based on the weight of the shell, of a crosslinking comonomer, when at least about 50% by weight of methyl methacrylate is used as a comonomer in the shell.An improved liquid marking composition is also disclosed.

Abstract: Uniformly sized polymer particles of 1-50 .mu.m diameter are made by gradually combining a water-insoluble monomer mixture with an aqueous dispersion of emulsion-polymerized polymer particles in the presence of a dispersion stabilizer and an oil-soluble, free-radical polymerization initiator.

Abstract: Multi-stage polymer particles containing one or more void space(s) therein are produced by sequential emulsion polymerization of an essentially low-acid earlier polymer stage, encapsulation of said low-acid polymer stage with at least a final polymer stage, contacting said polymer particles with a non-polymeric carboxylic acid or anhydride to permit the acid or anhydride to be absorbed into said low-acid polymer stage and swelling the polymer particles by contacting the particles with an aqueous base. The low-acid polymer stage is formed by emulsion polymerizing a monomer system comprising ethylenically unsaturated monomer(s) and containing less than 5% by weight of monomer(s) containing acid functionality. The low-acid polymer stage is swubsequently encapsulated by one or more polymer stages by emulsion polymerizing ethylenically unsaturated monomer(s) in the presence of the low-acid polymer stage. The final stage has a glass transition temperature (Tg) of about 50.degree. C.

Abstract: Multi-stage polymer particles containing one or more void space(s) therein are produced by sequential emulsion polymerization of an essentially low-acid earlier polymer stage, encapsulation of said low-acid polymer stage with at least a final polymer stage, contacting said polymer particles with a non-polymeric carboxylic acid to permit the acid to be absorbed into said low-acid polymer stage and swelling the polymer particles by contacting the particles with an aqueous base. The low-acid polymer stage is formed by emulsion polymerizing a monomer system comprising ethylenically unsaturated monomer(s) and containing less than 5% by weight of monomer(s) containing acid functionality. The low-acid polymer stage is subsequently encapsulated by one or more polymer stages by emulsion polymerizing ethylenically unsaturated monomer(s) in the presence of the low-acid polymer stage. The final stage has a glass transition temperature (Tg) of about 50.degree. C.

Abstract: The present invention is concerned with the production and use of water-insoluble particulate heteropolymers made by sequential emulsion polymerization in dispersed particles of which a "core" of a polymeric base is at least partially encased in a "sheath" polymer that is permeable to an acid, such as acetic acid, adapted to cause swelling of the core by neutralization. The aqueous dispersion of the acid-swollen, base-containing core/sheath particles is useful in making water-base coating compositions, microvoids being formed in cores of the swollen particles in the film during the drying thereof. Thus, the heteropolymer dispersion can serve as an opacifying agent in coating compositions, such as water-base paints, as a supplement or replacement of part or all of the pigmentary material or extenders that would otherwise be used in such coating compositions.

Abstract: The present invention is concerned with the production and use of water-insoluble particulate heteropolymers made by sequential emulsion polymerization in dispersed particles of which a "core" of a polymeric acid is at least partially encased in a "sheath" polymer that is permeable to a volatile base, such as ammonia or an organic amine, adapted to cause swelling of the core by neutralization. The aqueous dispersion of the acid-containing core/sheath particles is useful in making water-base coating compositions wherein it may serve as the binder or as a part thereof. In that use, the heteropolymer dispersion serves to provide desirable rheological control of the coating compositions when a volatile base is used to at least partially (to a pH of at least 6) neutralize the heteropolymer. Thus, the heteropolymer dispersion can serve as a thickener, or part thereof in coating compositions, such as water-base paints.

Abstract: The present invention is concerned with the production and use of water-insoluble particulate heteropolymers made by sequential emulsion polymerization in dispersed particles of which a "core" of a polymeric acid is at least partially encased in a "sheath" polymer that is permeable to a volatile base, such as ammonia or an organic amine, adapted to cause swelling of the core by neutralization. The aqueous dispersion of the acid-containing core/sheath particles is useful in making water-base coating compositions wherein it may serve as an opacifying agent when a volatile base is used to at least partially (to a pH of at least 6) neutralize the heteropolymer, microvoids being formed in cores of the swollen particles in the film during the drying thereof.

Abstract: On both heels of a racing plate a boss is formed having a top surface lying substantially flush with the top surface of the shoe, and an upwardly facing opening including a shallow recess and a mortise extending completely through the shoe is formed in each boss for receiving an insert. The insert formed of abrasion resistant material has a capital which lies in the recess, and a tenon which slides snuggly into the mortise and is held in place by a resilient O-ring. The insert capital supports the side walls of the recess and the recess walls exclude dirt from wedging between the capital and recess floor and lifting out the insert. A calk is made by forming a cleat on the insert capital; without a cleat, the insert is a wear plate whose top surface is flush with the top surface of the boss, providing a zone of increased wear resistance to decrease the wear of the heels.

Abstract: In a reel-to-reel longitudinally scanned tape transport or recorder, a length of media is positioned to fly in transducing relationship with a transducing head. The transducing head is mounted on a rotatable turntable rotor. The rotor includes a substantially circular member with concentric horizontal surfaces projecting in separate vertical planes. A cam shaped contour is fabricated on one of the horizontal surfaces with the transducing means positioned at the peak or crown of said cam shaped surface. There is a gradual roll off between the crown and the lowest point of the cam shaped surface. The roll off creates a converging channel which allows a sufficient volume of air to enter the interface between the media and the head and a diverging channel which allows the air to be bled off.

Abstract: In a rotating head magnetic tape transport, magnetic media is transported from a supply spool to a take-up spool. Interlayer slippage, due to air entrapped between tape layers, is reduced by impressing a waveform on the take-up spool motor voltage during high speed search. The impressed waveform has a high acceleration component. As a result of the impressed waveform, a continual jerking action is imparted to the tape to squeeze out entrapped air and leave said tape in a state of tension or tightly wound.

Abstract: A flying head, helical scan magnetic recording device comprises a tape source, a mandrel for supporting a helical wrap of magnetic tape, a rotor which is lobed with respect to the mandrel axis and a tape sink. The lobed rotor carries one or more magnetic heads at substantially the peak of the lobe around a flying scan path in non-contact, microinch adjacency to the magnetic tape supported on the mandrel. The major portion of the rotor, however, is recessed with respect to the magnetic tape, thereby minimizing the tendency of the tape to shear off the air bearing film carried by the rotor. The result is enhanced dynamic air bearing support of the tape in the immediate vicinity of the flying head.