Abstract: Li-ion rechargeable battery cell electrode and electrolyte/separator elements formulated as layers of plasticized polymeric matrix compositions are laminated with electrically conductive collector elements to form a unitary battery cell structure. Adhesion between the electrode and collector elements is enhanced by pretreatment of the collector elements in which a 0.25% to 3.0% solution of a polymeric material compatible with said matrix polymer is applied to a collector foil or grid and dried to form a coated film, and the resulting coated collector element is heated within the range of about 250.degree. to 450.degree. C. for about 5 to 60 seconds.

Abstract: Li-ion rechargeable battery cell electrode and electrolyte/separator elements formulated as layers of plasticized polymeric matrix compositions are laminated to form a unitary battery cell structure. The structure may be stored indefinitely, since it is essentially devoid of electrolyte solution which typically comprises a moisture-sensitive lithium salt. Prior to the battery's being put into service, the plasticizer of the polymeric composition is removed by leaching with a selective solvent and is replaced with a lithium salt electrolyte solution by simple imbibition. The battery thus activated may then be charged and recharged in the usual manner.

Abstract: Li-ion rechargeable battery cell electrode and electrolyte/separator elements formulated as layers of plasticized polymeric matrix compositions are laminated to form a unitary battery cell structure. The structure may be stored indefinitely, since it is essentially devoid of electrolyte solution which typically comprises a moisture-sensitive lithium salt. Prior to the battery's being put into service, at least a portion of the compatible polymeric composition plasticizer is displaced by contact with a lithium salt electrolyte solution or is removed by extraction with a selective solvent and replaced with the electrolyte solution by simple imbibition. The battery thus activated may then be charged and recharged in the usual manner.

Abstract: A time index for temporal databases is provided which enables the retrieval of database object versions that are valid during specified time periods. Unlike prior access and retrieval structures, the present index is based on objects whose search values are time intervals rather than time points. A series of ordered indexing points is defined by the start and end of object version intervals and these points are used to build an indexing structure, which may take the form of a B.sup.+ -tree. Each leaf node entry of the B.sup.+ -tree represents an indexing point and has an associated bucket of pointers which identify all object versions that are valid at that time. Storage space is reduced by including only incremental change indicators in the buckets of non-leading leaf entries and calculating needed pointers from such indicators.

Abstract: A polymeric film useful as an interelectrode separator or electrolyte member in electrolytic devices, such as rechargeable batteries, comprises a copolymer of vinylidene fluoride and hexafluoropropylene, a medium to high-boiling plasticizer, and a finely divided inorganic filler which has been subjected to actinic radiation or thermal energy to cause crosslinking thereof in the presence of a crosslinking agent selected from the group consisting of an acrylate ester, di- or triallyl ester and a di- or triglycidyl ether.

Abstract: Lithium intercalation compounds suitable for use in high capacity secondary battery electrodes are prepared by reacting together at a temperature in the range of about 800.degree. to 900.degree. C. lithium and manganese compounds in a stoichiometric ratio resulting in a Li.sub.x Mn.sub.2 O.sub.4 compound wherein x is within the range of about 1.00 to 1.20. The resulting compound is annealed at a temperature in excess of about 800.degree. C. and cooled to at least about 500.degree. C. at the rate less than about 10.degree. C. per hour before being finally cooled to ambient working temperature. Intercalation electrodes comprising these lithiated compounds are used in secondary batteries to yield stable, extended capacities in excess of 110 AHr/Kg.

Abstract: Irreversible loss of lithium during the initial discharge cycle of secondary batteries with carbon intercalation electrodes is substantially reduced by employing as the cell electrolyte a non-aqueous solution of LiPF.sub.6 in a mixture of dimethylcarbonate and ethylene carbonate. By this means, in a secondary battery cell comprising, for example, a Li.sub.1+x Mn.sub.2 O.sub.4 positive electrode and a graphite negative electrode, up to about 90% of the theoretical level of lithium can be reversibly cycled at an exceptionally high rate of about C/1 (complete discharge in one hour).

Abstract: A flexible polymeric film useful as an interelectrode separator or electrolyte member in electrolytic devices, such as rechargeable batteries, comprises a copolymer of vinylidene fluoride with 8 to 25% hexafluoropropylene. The film may be cast or formed as a self-supporting layer retaining about 20% to 70% of a high-boiling solvent or solvent mixture comprising such solvents as ethylene carbonate, propylene carbonate, dimethyl carbonate, and dibutyl phthalate. The film may be used in such form or after leaching of the retained solvent with a film-inert low-boiling solvent to provide a separator member into which a solution of electrolytic salt is subsequently imbibed to displace retained solvent or replace solvent previously leached from the polymeric matrix.

Abstract: A semiconductor diode laser comprising an active layer (12) having multiple compressively strained quantum wells (54) of AlGaInAs sandwiched between barriers (52) of AlGaInAs lattice-matched to InP and of a precisely defined bandgap dependent on the composition of the quantum wells. The active layer is surrounded by oppositely doped cladding layers (48, 50, 52, 58, 60) so as to form an optical waveguide. The laser very efficiently emits 1.3-.mu.m light, particularly at high operating temperatures.

Abstract: A cryptographic certificate attesting to the authenticity of original document elements, such as time of creation, content, or source, will lose its value when the cryptographic function underlying the certifying scheme is compromised. The present invention provides a means for extending the reliability of such a certificate by subjecting, prior to any such compromise, a combination of the original certificate and the document digital representation from which that certificate was derived to a scheme based on a different and ostensibly less vulnerable function. The new certificate resulting from this procedure extends the validity of the original authenticity by implacably incorporating the original certificate at a time when that certificate could only have been derived by legitimate means.

Abstract: A system for detecting arcing faults in DC electrical cable power distribution circuits, typically in telecommunications networks, monitors the power spectrum of distribution lines over a frequency band of about 4 Hz to 5 KHz in which current surges characteristic of arcing line faults have been found to occur. The system compares power levels in this detection band with a threshold level typical of normal communications traffic and registers an alarm condition when an excess indicative of arcing is detected.

Abstract: Data transmissions from each of a multiplicity of users in a fiber-optic communications network employ pulse stream frequencies which uniquely differ by a given period offset, .DELTA.t, and are thus characteristic of each particular user. Such pulse streams 11, 12, etc. are multiplexed for transmission through the network, yet may be individually extracted at the facilities of a receiving user by means of a selector 26 comprising one or more non-linear optical logic devices 35, such as bistable semiconductor laser amplifiers or self-electrooptic effect devices, which are associated with optical delay means 34 having period offset characteristics peculiar to that of a specific transmitting user.

Abstract: A rechargeable battery comprises lithium intercalation compound electrodes and an interposed electrolyte of flexible polymer containing a lithium salt dissolved in a polymer-compatible solvent. Preferred components include tertiary lithium manganese oxide compound positive electrodes, carbon negative electrodes, and poly(vinylidene fluoride) copolymer electrolyte layers containing about 20 to 70% of a solution of lithium salt in a medium boiling solvent comprising such solvents as ethylene carbonate, propylene carbonate, and dimethyl carbonate. The electrolyte layers may be employed in the form of individual separator films or as a coated component of multilayer battery structures to provide electrical ionic conductivity up to about 10.sup.-3 S/cm.

Abstract: A method of preparing a Li.sub.1+1 Mn.sub.2 O.sub.4 (0<x<1) intercalation compound useful as a positive intercalation electrode in a lithium metal free non-aqueous secondary battery comprises reacting LiMn.sub.2 O.sub.4 or .lambda.-MnO.sub.2 with LiI in an evacuated container at about 150.degree. C. or with reflux in acetonitrile.

Abstract: A method for the selective detection of liquid phase hydrocarbons in the C.sub.6 -C.sub.16 range includes a matrix comprising a silicone polymer having dispersed therein a conductive carbon black filler of high structure and comprises signaling the presence of hydrocarbon liquid phase when the electrical resistivity of the sensor increases to a preselected threshold level intermediate the vapor and liquid phase resistivities.

Abstract: A tellurite glass particularly usable for an amplifier or oscillator utilizing an optical fiber or other guided wave structure. In approximate terms, the glass contain between 58 and 84 molar % of TeO.sub.2, up to 24 molar % Na.sub.2 O, and between 10 and 30 molar % of ZnO. Other alkali and divalent metals may be substituted for the Na and Zn respectively. Combinations of these tellurite glasses can be formed as an optical fiber (10) having a core (12) with a higher refractive index than that of the cladding (14). The tellurite glass of the core, when composed of at least 0.05 molar % Na.sub.2 O, can be doped with large amounts of Er, Pr, or Nd to act as a fiber amplifier at 1.5 or 1.3 .mu.m when pumped with light of a specified shorter wavelength. The core can be doped with other rare-earth metals which would provide optical amplifiers or oscillators at wavelengths appropriate to their lasing characteristics.

Abstract: A method and resulting structure for growing a crystalline perovskite film (16) on a silicon dioxide layer (12) by means of an intermediate template layer (14) of a c-axis oriented layered perovskite, such as bismuth titanate. The perovskite film can be ferroelectric lead-lanthanum zirconate titanate or conductive cubic metal oxides used as electrodes for the ferroelectric.

Abstract: An apparatus and method for flattening the gain of an optical fiber amplifier (18) doped with an ion such as erbium and which is pumped by a pump laser (20). Optical couplers (32, 34) inserted before and after the fiber amplifier couple the main optical path to an optical ring passing through the fiber amplifier so as to form a ring laser. An optical isolator (32) placed in the ring causes the lasing light to only counterpropagate relative to the optical signal being amplified. When the fiber amplifier primarily exhibits inhomogeneous broadening and the ring lases, the lasing light clamps the gain to a value determined by the loop loss, and the value of the clamped gain is relatively uniform across a wide bandwidth.

Abstract: Copper vanadium bronzes suitable for use in positive intercalation electrodes in lithium secondary batteries are prepared by partial oxidative removal of copper ions from .beta.- and .epsilon.-Cu.sub.y V.sub.2 O.sub.5 bronzes. A preferred one of the resulting electrode materials is capable of intercalating up to about 1.4 Li per vanadium to yield a theoretical energy density of about 1200 Wh/Kg.

Abstract: A system for time-stamping a digital document, including for example text, video, audio, or pictorial data, protects the secrecy of the document text and provides a tamper-proof time seal establishing an author's claim to the temporal existence of the document. Initially, the author reduces the document to a number by means of a one-way hash function, thereby fitting a unique representation of the document text. In one embodiment of the invention the number is then transmitted to an outside agency where the current time is added to form a receipt which is certified by the agency using a public key signature procedure before being returned to the author as evidence of the document's existence. In later proof of such existence, the certificate is authenticated by means of the agency's public key to reveal the receipt which comprises the hash of the alleged document along with the time seal that only the agency could have signed into the certificate.