摘要:
A method of preparing tetraketone precursors which are useful in the production of high temperature resistant polyquinoxaline resins. Suitable diketones are oxidized with a halogenating agent, such as cupric halide or hydrogen bromide, and dimethylsulfoxide to produce the corresponding tetraketone. The tetraketones which can be produced by the instant process have the formula: ##STR1## wherein R is hydrogen or an aryl, substituted aryl, heterocyclic or substituted heterocyclic radical and R' is an aryl, substituted aryl, arylalkyl, arylether, arylthioether, arylsulfoxide, arylsulfone, heterocyclic or substituted heterocyclic radical.
摘要:
The present invention relates to conjugated polymers and a method for their synthesis. Furthermore, the present invention relates to electro-synthesis methods for producing polymers that include the use of at least one Lewis acid and at least one proton trap to form organic conjugated polymers having elevated refractive indices. In one embodiment, the present invention relates to an organic polymer having an elevated refractive index, the organic polymer formed by a process comprising the steps of: providing a solution of unsaturated organic monomer units and at least one acidic component; impeding saturation of the unsaturated organic-monomer units by at least one protic element in the solution; and polymerizing the unsaturated organic monomer units to form a conjugated organic polymer having a refractive index of at least about 2.3 for electromagnetic energy having a wavelength of about 700 nm.
摘要:
A new class polyimide and polyimide precursors based on diaryl oxyalkylene diamines, such as 1,3-bis[4-aminophenoxy]-2,2-dimethyl propane, a process for their preparation and their use as the continuous phase for the manufacture of composites and composite laminates reinforced by reinforcing agents such as carbon fibers, Kevlar.TM., and other similar high strength reinforcing agents. The polyimides and molecular composites obtained from the diamines according to the invention show thermoplastic properties, excellent flex fatigue and fracture resistance, and excellent thermal and oxidative stability.
摘要:
Enamine ketone and enonesulfide polymeric solids are prepared by reacting liquid or low-melting propynone terminated enamine ketone and enonesulfide prepolymers in one-step, or more preferably, in two-step processes. Properties of the resulting polymers are determined by the nature of the reactant selected and by the relative amounts of reactants employed. Where the prepolymers formed possess terminal propynone groups, the prepolymers can subsequently be cross-linked. Copolymers can also be formed by reacting the prepolymers of the invention with vinyl-type monomers to form polymers with cross-linked networks. The polymerization techniques disclosed can be employed to produce thermoplastic, thermoset, and elastomeric products, and they are especially useful in reaction injection molding processes, in adhesive systems, in composite formations, for linings, and gaskets which require chemical resistance.
摘要:
An electronic stimulating device is disclosed, with the stimulating device particularly illustrated being a transcutaneous nerve stimulating (TENS) device for effecting suppression of pain by nerve fiber stimulation. Biphasic constant current output pulses are applied to a user through electrode pairs noninvasively positioned at the skin of the user. Microprocessor generated control pulses control generation of the biphasic output pulses at a biphasic output stage associated with each electrode pair, and the generated biphasic output pulses are capacitively coupled from each output stage which also includes a bleeder network for effecting capacitor discharge. Stimulation may be continuously applied at a level selected by the user or may be applied in timed varying intensities the maximum level of which is selectable, and displays of intensity and sensed faults, including low battery voltage, are also provided.
摘要:
A moldable and/or extrudable poly(enamine ketone-co-alkylene ether) block copolymer is disclosed which has the formula shown below: ##STR1## wherein R' is H or alkyl, alkoxyl, cycloalkyl, cycloalkoxyl and aryl and aryloxyl, A is a poly(enamine ketone) sequence and B is a polyalkylene ether sequence. The poly(enamine ketone-co-alkylene ether) block copolymer is preferably prepared under mild condition by reacting a bispropynone with an amine-terminated poly(alkylene ether); a bispropynone with an organic diamine and an amine-terminated poly(alkylene ether); or by reacting a preformed propynone-terminated poly(enamine ketone) with an amine-terminated poly(alkylene ether).The compolymers have excellent mechanical properties, are moldable and extrudable and are useful for the manufacture of articles such as films, sheaths, fibers for textile products, and other moldable and/or extrudable articles and RIM shaping. These materials are also useful as bonded or welded linings and as hot-melt adhesives.
摘要:
An electrosurgical generator having a source of electrosurgical energy connected to a patient and including control circuitry for decreasing the output power from the source with increasing patient impedance, the rate of power decrease being substantially greater than that which would result if the output voltage from the source were maintained constant over the range of increasing patient impedance. The control circuitry may, in particular, decrease the output power over the range of increasing patient impedance in accordance with the square of the impedance.
摘要:
Patient contact area measurement method and apparatus including a first electroconductive contact element adapted for contact with the patient; a second electroconductive contact element separated from the first contact element and also adapted for contact with the patient; and measuring circuitry disposed between the first and second electroconductive contact elements for measuring the area of contact of the patient with respect to the contact elements. The electroconductive contact elements may comprise (a) each electrode of a split electrosurgical patient electrode, (b) the active and patient electrodes employed in electrosurgery or (c) a cryosurgical probe together with a monitor electrode adapted for contact with the patient.
摘要:
An electrosurgical method and apparatus for coagulating by fulguration where the electrical discharge is established through a formation of flowing inert gas where the formation may either be a diffuse blanket of the flowing gas or a well defined column thereof.
摘要:
The present invention relates to conjugated polymers and a method for their synthesis. Furthermore, the present invention relates to electro-synthesis methods for producing polymers that include the use of at least one Lewis acid and at least one proton trap to form organic conjugated polymers having elevated refractive indices. In one embodiment, the present invention relates to an organic polymer having an elevated refractive index, the organic polymer formed by a process comprising the steps of: providing a solution of unsaturated organic monomer units and at least one acidic component; impeding saturation of the unsaturated organic-monomer units by at least one protic element in the solution; and polymerizing the unsaturated organic monomer units to form a conjugated organic polymer having a refractive index of at least about 2.3 for electromagnetic energy having a wavelength of about 700 nm.