30 results about "Linear ablation" patented technology

This invention is a circumferential ablation device assembly which is adapted to forming a circumferential conduction block in a pulmonary vein. The assembly includes a circumferential ablation element which is adapted to ablate a circumferential region of tissue along a pulmonary vein wall which circumscribes the pulmonary vein lumen, thereby transecting the electrical conductivity of the pulmonary vein against conduction along its longitudinal axis and into the left atrium. The circumferential ablation element includes an expandable member with a working length that is adjustable from a radially collapsed position to a radially expanded position. An equatorial band circumscribes the outer surface of the working length and is adapted to ablate tissue adjacent thereto when actuated by an ablation actuator. The equatorial band has a length relative to the longitudinal axis of the expandable member that is narrow relative to the working length, and is also substantially shorter than its circumference when the working length is in the radially expanded position. A pattern of insulators may be included over an ablation element which otherwise spans the working length in order to form the equatorial band described. The expandable member is also adapted to conform to the pulmonary vein in the region of its ostium, such as by providing a great deal of radial compliance or by providing a taper along the working length which has a distally reducing outer diameter. A linear ablation element is provided adjacent to the circumferential ablation element in a combination assembly which is adapted for use in a less-invasive “maze”-type procedure in the region of the pulmonary vein ostia in the left ventricle.

This invention is a circumferential ablation device assembly which is adapted to forming a circumferential conduction block in a pulmonary vein. The assembly includes a circumferential ablation element which is adapted to ablate a circumferential region of tissue along a pulmonary vein wall which circumscribes the pulmonary vein lumen, thereby transecting the electrical conductivity of the pulmonary vein against conduction along its longitudinal axis and into the left atrium. The circumferential ablation element includes an expandable member with a working length that is adjustable from a radially collapsed position to a radially expanded position. An equatorial band circumscribes the outer surface of the working length and is adapted to ablate tissue adjacent thereto when actuated by an ablation actuator. The equatorial band has a length relative to the longitudinal axis of the expandable member that is narrow relative to the working length, and is also substantially shorter than its circumference when the working length is in the radially expanded position. A pattern of insulators may be included over an ablation element which otherwise spans the working length in order to form the equatorial band described. The expandable member is also adapted to conform to the pulmonary vein in the region of its ostium, such as by providing a great deal of radial compliance or by providing a taper along the working length which has a distally reducing outer diameter. A linear ablation element is provided adjacent to the circumferential ablation element in a combination assembly which is adapted for use in a less-invasive “maze”-type procedure in the region of the pulmonary vein ostia in the left ventricle.

An intravascular device for the formation of linear lesions which has particular utility in the treatment of atrial fibrillation and flutter. The intravascular device has an outer delivery member with a distal section which has an elongated opening and a support element coextending with the opening. An EP device having a plurality of electrodes on its distal section is slidably disposed within the inner lumen of the delivery member but it is secured by its distal end within the distal extremity of the delivery member at least while in operation. In this manner an axial force in the proximal direction on the proximal extremity of the EP device, which extends out of the patient during the procedure, will cause the distal shaft section of the EP device to arch outwardly out of and away from the distal section of the delivery shaft along an inner side of the curved distal section and engage the surface of the patient's heart chamber. RF electrical energy delivered to the electrodes on the distal shaft section of the EP device will form a linear lesion which terminates the fibrillation or flutter.

An intravascular device for the formation of linear lesions which has particular utility in the treatment of atrial fibrillation and flutter. The intravascular device has an outer delivery member with a distal section which has an elongated opening and a support element coextending with the opening. An EP device having a plurality of electrodes on its distal section is slidably disposed within the inner lumen of the delivery member but it is secured by its distal end within the distal extremity of the delivery member at least while in operation. In this manner an axial force in the proximal direction on the proximal extremity of the EP device, which extends out of the patient during the procedure, will cause the distal shaft section of the EP device to arch outwardly out of and away from the distal section of the delivery shaft along an inner side of the curved distal section and engage the surface of the patient's heart chamber. RF electrical energy delivered to the electrodes on the distal shaft section of the EP device will form a linear lesion which terminates the fibrillation or flutter.

A preformed catheter set for production of linear ablation lines in the left and right atrium for treatment of atrial fibrillation includes at least a first catheter including a pre-shaped distal segment having a distal linear ablation antenna and a U-shaped curve portion proximal to the distal linear ablation antenna.

The invention relates to a preparation method of a thermal-protection ablative material, and relates to a preparation method of a thermal-protection material. The invention aims at solving a technical problem of high density of a carbonized-type lightweight ablative material with phenolic resin as a substrate. According to the method, boron phenolic resin is prepared into a boron phenolic resin acetone solution; chopped carbon fiber is cleaned and oxidized, and is processed by using a coupling agent; a uniform mixture of a micro-spherical filling material, carbon nano-tubes, and the chopped carbon fiber are added into the boron phenolic resin solution, and the mixture is uniformly mixed; acetone is evaporated by standing, such that a mixed paste is obtained; a phenolic honeycomb cut into a mold inner cavity shape is placed into the mold; the mixed paste is filled into the phenolic honeycomb, such that a composite blank is obtained; and the composite blank is cured and shaped, such that the thermal-protection ablative material is obtained. The material has a low density of 0.2-0.4g / cm<3>, a linear ablation rate of 0.033-0.035mm / s, and a mass ablation rate of 0.0167-0.0187g / s. The material is suitable to be used as a space vehicle thermal-protection material.

The invention discloses an ablation-resisting composite material resin composition and a preparation method of an ablation-resisting composite material, belonging to the field of high polymer composite material preparation. The composition comprises phenolic resin, poly(bisphenoxy)phosphazene, a coupling agent and silicon oil. The preparation method of the composite material comprises the following steps: respectively dissolving poly(bisphenoxy)phosphazene and the phenolic resin in tetrahydrofuran for complete dissolution, mixing to form a homogeneous solution, then coating the solution on carbon fiber cloth, and drying the carbon fiber cloth in a vacuum oven for 12 hours at the temperature of 50 DEG C after airing; and cutting the fiber cloth into square blocks and overlapping the squareblocks in a mould, heating for 1 hour at the temperature of 100 DEG C so as to completely melt boron phenolic resin, then heating to 120 DEG C to carry out procuring for 1 hour, finally heating to 180 DEG C and curing for 6 hours at the pressure of 5MPa, taking out and cooling to room temperature so as to prepare the ablation-resisting composite material. The composite material has the advantagesof higher flexural modulus and thermal deformation temperature as well as lower linear ablation rate and quality ablation rate; and the ablation resistance of the composite material is improved.

An intravascular device for the formation of linear lesions which has particular utility in the treatment of atrial fibrillation and flutter. The intravascular device has an outer delivery member with a distal section which has an elongated opening and a support element coextending with the opening. An EP device having a plurality of electrodes on its distal section is slidably disposed within the inner lumen of the delivery member but it is secured by its distal end within the distal extremity of the delivery member at least while in operation. In this manner an axial force in the proximal direction on the proximal extremity of the EP device, which extends out of the patient during the procedure, will cause the distal shaft section of the EP device to arch outwardly out of and away from the distal section of the delivery shaft along an inner side of the curved distal section and engage the surface of the patient's heart chamber. RF electrical energy delivered to the electrodes on the distal shaft section of the EP device will form a linear lesion which terminates the fibrillation or flutter.

A catheter is provided with an anchoring member for anchoring a part of a linear ablating head of the catheter to a structure. The structure can be a cryogenically anchored point catheter. This allows the surgeon to position the linear catheter more exactly in the heart chamber and overcomes the adverse effects of the slippery and irregular heart chamber walls.

The invention discloses an organic-inorganic double network structure phenolic aldehyde / alumina aerogel composite material. The organic-inorganic double network structure phenolic aldehyde / alumina aerogel composite material is obtained by the following steps: growing organic-inorganic double network structure composite gel in situ by taking resorcinol, formaldehyde and crystalline aluminum chloride as raw materials through hydrolysis and condensation reaction; depositing an alumina atomic layer on the double network structure composite gel with a chemical liquid phase method; lastly, performing ageing and drying. According to the composite material disclosed by the invention inorganic reinforcing fibers, infrared shielding particles and other functional modification fillers can be added asneeded to further improve the mechanical properties and thermal insulation performance; the composite material obtained has the characteristics of low density, low thermal conductivity, high mechanical strength and low linear ablation rate, is suitable for light-weight thermal protection / insulation materials of spacecraft thermal protection systems, and has great application value.

The invention provides a ZrC-SiC-LaB6 ternary superhigh temperature ceramic composite material and a preparation method thereof, relates to a superhigh temperature ceramic composite material and a preparation method thereof, and mainly solves the problem that the existing ZrC ceramic is large in fragility, low in density, strength and rigidity, and poor in erosion performance. The method is as follows: performing ultrasonic dispersion on SiC crystal whisker, mixing the SiC crystal whisker with ZrC and SiC nano particles and LaB6, then performing ball milling on mixture to obtain slurry, and drying the slurry to obtain mixed powder; and filling the mixed powder into a graphite mould, performing hot-press sintering on the mixed powder under the protection argon, so as to obtain the ceramic of which the density is more than or equal to 98%, wherein the mass ablation rate is 0.74-1.11*10<-4>g / s, and the linear ablation rate is 1.50-2.78*10<-3>mm / s. The material is used for throat liner nozzle jets and jet vanes of solid rocket engines, nose cones and leading edges of superspeed air vehicles, cladded fuel particle coatings of high-temperature gas cooled reactors, coatings of thermophotovoltaic radiators, and the like.

The invention discloses a lightweight slightly ablative composite material, and a preparation method thereof. According to the preparation method, zirconium boron modified phenolic resin is taken as amatrix, and ceramic fiber needled felt is taken as a reinforcement, at 2000 DEG C, 30s of ablation is carried out with oxyacetylene flame, the mass ablation rate is controlled to be 0.0025-0.02 g / s,and the linear ablation rate is controlled to be 0.0085 to 0.0520 mm / s. The preparation method comprises the following steps: synthesizing preparation of the zirconium boron modified phenolic resin, preparation of a phenolic resin solution, impregnating of the flexible ceramic fiber needled felt with the phenolic resin solution, curing and cross-linking, and drying. The lightweight slightly ablative composite material possesses advantages such as low density, excellent anti-insulation performance, and simple preparation process.

The invention belongs to the technical field of medical electronics, and particularly relates to a radio frequency adjustable phase difference power amplifier circuit realizing linear ablation. The structure of the circuit comprises a phase control unit, a radio frequency amplitude control unit, a radio frequency resonance and filtering circuit, and an impedance matching network. Due to adoption of the impedance matching network, changing myocardial impedance in ablation is equivalent within a rated load range of the circuit, so that the circuit interior loss is reduced, and output frequency is stabilized; due to adoption of a soft-switching technology, zero voltage opening or zero voltage derivative opening of an electronic switching tube is realized, so that switching loss is lowered, and the working efficiency is improved. Through adoption of the circuit, the defect that continuous ablation lesions are hard to form in a conventional point-by-point dispersing radio frequency ablation technology is overcome, and continuous linear ablation effect is produced through adjustment of phase difference of radio frequency output voltages of adjacent ablation electrodes, so that continuous linear ablation of myocardial tissue is realized.

An ablation device for cardiac tissue, especially for forming a circular lesion around a vessel orifice in the heart, comprises a steerable catheter that is provided in the region of its distal end with an abutment device for holding the distal end of the catheter on a cardiac vessel orifice; and a linear ablation applicator that is disposed distally or proximally relative to the abutment device of the catheter and can be brought from a straight passive position into a radially expanded, approximately circular-arc-type encircling ablation position.

The invention relates to a metal sputtering thin film technology-based ablation sensor. The metal sputtering thin film technology-based ablation sensor includes a shell with an ablation sensor sensitive assembly arranged therein; the ablation sensor sensitive assembly is composed of a metal wire grid, a substrate material and leads; the metal wire grid is plated on the substrate material through a metal sputtering thin film technology; one end of each lead is connected with the metal wire grid, and the other ends of the lead extend out from the shell, so that the signals of the metal wire grid can be transmitted to a conditioning module; and a filler is arranged between the shell and the ablation sensor sensitive assembly in a plugging manner. With the metal sputtering thin film technology-based ablation sensor of the invention adopted, real-time and on-line measurement of the linear ablation amount of a C / C composite material can be realized. According to the metal sputtering thin film technology-based ablation sensor, the magnitude of the output signals of the sensor is in direct proportion to the change of the linear ablation amount of the C / C composite material. The metal sputtering thin film technology-based ablation sensor has the advantages of high resolution and high measurement precision, and just lightly damages the body of a measured material.

A delivery catheter having a shaft with a distal end and a proximal end for delivering an ablation probe to a body site. The delivery catheter comprises mounting members located at the distal end configured to receive an ablation probe; and attachment members configured to attach the distal end to a tissue surface. The delivery catheter preferably configured to allow an ablation probe mounted on the distal end to be manipulated so as to extend from the distal end in a direction selected from a range of directions. Even more preferably, the delivery catheter is configured to allow an ablation probe mounted on the distal end to be manipulated so as to move along a tissue surface and perform linear ablation. The invention also provides a system comprising the delivery catheter of the invention and an ablation device having an ablation probe, wherein the delivery catheter and the ablation probe are configured to allow the ablation probe to be mounted at the distal end of the delivery catheter.

The invention relates to the field of polyester, and the synthesizing and applications thereof. The invention discloses a boron-containing polyester with a specific structure represented as the following, wherein n is no smaller than 1. The invention also discloses a synthesizing method of the boron-containing polyester. The method comprises the steps that: raw materials are weighed according to a molar ratio that resorcinol: boric acid=1.0-3.0:1; a feeding reaction is carried out, wherein the materials are added into a reactor, such that resorcinol and boric acid are subjected to a sufficient reaction in the reactor; and a product is obtained, wherein the reaction product after the feeding reaction is discharged, such that the boron-containing polyester is obtained. The invention also discloses applications of the boron-containing polyester: (1) the polyester can be adopted as a curing agent and especially a curing agent of epoxy resin; with the ester, cured resin has fame-retardant performance that the epoxy resin cured product reaches an off-fire extinguishing effect or a short-time extinguishing effect, and he epoxy resin cured product has the properties of no smoke or less smoke; the cured epoxy resin can be applied as an ablation material in an aerospace field, wherein a linear ablation rate is no higher than -0.003mm / s, and mass ablation rate is no higher than 0.086g / s; and (2) the polyester can be applied as a flame retardant, wherein the boron-containing polyester provided by the invention is substantially non-flammable on fire, such that the ester can be directly used as the flame retardant.

A non-linear ablation device includes two opposing surfaces, which are associated with two overlying and separate compartments. A first compartment of the two overlying and separate compartments is configured to emit or resorb energy. A second compartment of the two overlying and separate compartments is configured to either resorb or emit energy to oppose a direction of energy transfer of the first compartment. Other embodiments of the non-linear ablation device are further disclosed.

The present application discloses an ablation device and system for treating atrial fibrillation, and a fixed pathway for ablation of persistent AF. The pathway consists of bilateral circumferential pulmonary sinus isolation ('2C') and three linear ablation groups ('3L'). The ablation device and system and the fixed pathway have the advantages of less radio frequency delivery, low X-ray irradiation frequency, and shorter time spent when used in surgery.

Devices and methods for creating radial-linear lesions in pulmonary vein antral tissue are disclosed. In an embodiment, a device includes an elongate shaft structure with a distal tip ablation region including a spline and an ablation element slidably coupled to the spline. The ablation element includes at least one of an ultrasound emitter, a high frequency ultrasound emitter, a laser, a radiofrequency electrode, a virtual radiofrequency electrode, or a cryogenic source. A backing balloon may be configured to push or pull the spline and the ablation element toward or against the pulmonary vein antral tissue. In an embodiment, the distal tip ablation region includes a splineless cryoballoon with at least one thermally conductive region.

This invention relates to a method for preparing ZrB2-ZrC-SiC multiphase ceramic at ultrahigh temperatures with near-zero ablation. The ZrB2-ZrC-SiC multiphase ceramic is prepared from: ZrB2 50-75 wt.%, ZrC 15-40 wt.%, SiC 10-20 wt.%, and ZrO2 as the combustion aid 6-16 wt.%. The ZrB2-ZrC-SiC multiphase ceramic has synergistic effects at high temperatures, which can result in good high-temperature properties. The ZrB2-ZrC-SiC multiphase ceramic has a room-temperature bending strength of 300-400 MPa, a Rockwell hardness of 88-92, and a linear ablation of 0.0003-0.001 mm / s. The ZrB2-ZrC-SiC multiphase ceramic has better oxidation resistance, better ablation resistance and lower sintering temperature compared with single phase ceramics, and has such advantages as good applicability, even distribution, no limit to product shapes and little shape change after 2400 s oxygen-ethylene combustion at 2800-3200 deg.C.

The invention discloses a standard substance for calibration of a plasma ablation tester and a preparation method thereof, and belongs to the technical field of measurement. The standard substance forcalibration of the plasma ablation tester is prepared from a composite material prepared from carbon fiber with the length being (6+ / -2) mm and S157 effective phenolic resin at the mass ratio being 1:(3.8-4.2), the standard substance is shaped like a circular block, the linear ablation rate is 0.484+ / -0.030 mm / s. The standard substance has the advantages of being uniform in stability, accurate and reliable in setting and the like, and is suitable for verification and calibration of the plasma ablation tester, and the preparation method is good in repeatability and convenient to operate.

The invention discloses an ablation-resisting composite material resin composition and a preparation method of an ablation-resisting composite material, belonging to the field of high polymer composite material preparation. The composition comprises phenolic resin, poly(bisphenoxy)phosphazene, a coupling agent and silicon oil. The preparation method of the composite material comprises the following steps: respectively dissolving poly(bisphenoxy)phosphazene and the phenolic resin in tetrahydrofuran for complete dissolution, mixing to form a homogeneous solution, then coating the solution on carbon fiber cloth, and drying the carbon fiber cloth in a vacuum oven for 12 hours at the temperature of 50 DEG C after airing; and cutting the fiber cloth into square blocks and overlapping the squareblocks in a mould, heating for 1 hour at the temperature of 100 DEG C so as to completely melt boron phenolic resin, then heating to 120 DEG C to carry out procuring for 1 hour, finally heating to 180 DEG C and curing for 6 hours at the pressure of 5MPa, taking out and cooling to room temperature so as to prepare the ablation-resisting composite material. The composite material has the advantagesof higher flexural modulus and thermal deformation temperature as well as lower linear ablation rate and quality ablation rate; and the ablation resistance of the composite material is improved.

The invention discloses a ceramic enhanced ethylene propylene diene monomer material. The ceramic enhanced ethylene propylene diene monomer material is prepared from the following materials in parts by weight: 100 parts of ethylene propylene diene monomer, 20 to 30 parts of ceramic fiber, 20 to 40 parts of white carbon black, 0.5 to 1 part of stearic acid, 1 to 2 parts of an accelerant TMTD (Tetramethylthiuram Disulfide), 1 part of KH550 and 1 to 2 parts of DCP (Dicumyl Peroxide). According to the ceramic enhanced ethylene propylene diene monomer material disclosed by the invention, the ceramic fibers are added into the ethylene propylene diene monomer so that the carbon content in the material is effectively reduced and the ratio of other metal materials is increased, so that the ablation resistance can be greatly improved under an oxygen-rich environment and normal work of a rocket engine is facilitated. The KH550 is added so that the compatibility among the ceramic fibers, the white carbon black and the ethylene propylene diene monomer is facilitated. The ceramic enhanced ethylene propylene diene monomer material has good mechanical properties and relatively low linear ablation rate, has good utilization performances and stable quality and meet actual research and development and production requirements.

The invention belongs to the field of lightweight ablation-resistant dissipation heat-proof composite materials, particularly relates to an ablation-resistant dissipation agent and application and aims to solve problems of high linear ablation rate and low dissipation agent content in a matrix of a dissipation heat-proof composite material. A dissipation agent alloy system comprises aluminum, silicon and boron, and the ternary dissipation agent is applied to the dissipation heat-proof composite material. An application method includes: firstly, dissipation agent preparation; secondly, base material treatment; thirdly, graphite crucible treatment; fourthly, vacuum gas pressure infiltration. The novel ternary dissipation agent is provided on the basis of a dissipation heatproof mechanism, aliquid ceramic protective layer for heat dissipation and oxygen dissipation can be formed under conditions of high temperature, high pressure and high-speed particle flow erosion, and the prepared lightweight ablation-resistant dissipation heat-proof composite material is used for manufacturing of throat inserts of solid rocket engine nozzles, gas rudders, end caps, wing leading edges and tail vanes of hypersonic aircrafts and steering porous plate components of missiles.