摘要:
A system and method of applying a known modification to a signal to enable a determination of a signal received by a first node is received directly from a second node or indirectly through a repeater. The repeater receives a primary signal and creates a secondary signal as a function of the primary signal and a known modification, wherein the known modification identifies the repeater. The primary signal is transmitted and injected with the secondary signal as the first signal to the primary receiver.
摘要:
The present invention is relates to an apparatus and method for the determination of the oxygen gas permeability of a polymer. In one embodiment, the present invention relates to an apparatus and method for determining the oxygen gas permeability of a polymer membrane (e.g., a polydimethylsiloxane and/or polysiloxane polymer or copolymer). In still another embodiment, the present invention relates to oxygen gas permeable polymer compositions.
摘要:
A method for calibrating an antenna and signal processing system enabling angle of arrival (AOA) determination for a frequency hopping signal, in which a calibration coefficient is determined in response to one or more calibration signals injected into the system at one or more of the frequencies in the hopping sequence and proximate in time to reception of the communication signal. The calibration coefficients are reflective of a frequency and time dependent parameter of a path between the antenna and wireless location sensor. The AOA is determined as a function of the calibration coefficient and the radio frequency energy of the received communication signal. Several embodiment of the method are illustrated.
摘要:
Block copolymers and star polymers having copolymer arms of PIB-PAN have been synthesized via living carbocationic polymerization and atom transfer radical polymerization in a methylene chloride/cyclohexanone solvent system.
摘要:
The present invention provides high mechanical strength amphiphilic polymer networks and implantable biological devices that are capable of encasing and, thus, immunoisolating biological material from the immunological response of a host individual. The present invention also provides methods for the formation of the amphiphilic networks and implantable biological devices. The present invention also provides a method for the treatment of type I diabetes mellitus comprising the steps of encasing a sufficient amount of islet of Langerhans cells within said biological device, wherein said biological device is capable of immunoisolating said encased islet cells upon implantation into an individual; implanting said biological device into a diabetic host individual; allowing said implanted biological device to remain implanted said diabetic individual for a time sufficient to normalize the blood glucose level in said diabetic individual.
摘要:
A dynamic star polymer contains a plurality of at least three substantially identical block copolymers, each block copolymer including an aromatic polymer moiety having a glass transition temperature of at least about 95.degree. C., and an aliphatic polymer moiety incompatible with the aromatic polymer moiety. The aromatic moieties of each of the formed block copolymers aggregate to form a chemically uncrosslinked core, while the aliphatic polymer moieties radiate outwardly from the core. The multi-arm star polymer is uniquely capable of changing its molecular structure under external influences, and the core thereof preferably exhibits thermoplastic characteristics.
摘要:
The synthesis and characterization of novel higher order, multi-arm star polymers comprising polyisobutylene arms connected to condensed cyclosiloxane cores are described. The synthesis has been achieved by hydrosilating olefin-capped (e.g., allyl- or isopropenyl-terminated) polyisobutylene with hydrogencyclosiloxanes carrying a plurality of Si--H groups and simultaneously and competitively converting SiH functions, in the presence of moisture, to Si--OH groups to rapidly self-condense or react with SiH groups to form coupled cyclosiloxane cores via core-core coupling. Thus, higher order stars having many more arms than first order stars can be formed.
摘要:
The synthesis and characterization of novel multi-arm star polymers comprising polyisobutylene arms connected to a well-defined, siloxane core are described. The synthesis has been achieved by hydrosilating olefin-capped (e.g., allyl- or isopropenyl-terminated) polyisobutylene with siloxanes carrying a plurality of Si--H groups.
摘要:
The synthesis and characterization of a series of novel (AB).sub.n multiblock copolymers, typically thermoplastic elastomers, containing polyisobutylene as the soft phase and polyamides as the hard phase are described. First, carboxyl ditelechelic polyisobutylene prepolymers and isocyanate ditelechelic polyisobutylene prepolymers were synthesized, both of which were subsequently reacted under solution polycondensation conditions with dicarboxylic acids and diisocyanates. The melting points of the polyamide hard phases were in the 223.degree.-284.degree. C. range. The decomposition temperatures (296.degree.-337.degree. C.) in air and nitrogen of these thermoplastic elastomers were quite similar; in contrast, these properties of polytetrahydrofuran-based thermoplastic elastomers are noticeably lower in air. Melt processing of these novel polyisobutylene-based thermoplastic elastomers is possible.
摘要:
Block copolymers compose a polyisobutylene rubbery soft segment of M.sub.n of about 5,000 to above 500,000 and glassy hard segments of M.sub.n of about 5,000 or higher and usually about 10,000 to 35,000 or more, are made by preparing a living polymer block of the polyisobutylene and then polymerizing on said living polyisobutylene block the glassy hard segments by adding thereto an electron donor having a donor number of 15 to 50 and then adding and polymerizing the monomers for the glassy hard segments. The monomers for the glassy hard segments are styrene and its derivatives and indene and its derivatives and mixtures thereof.