47results about How to "Reduce heat insulation" patented technology

The invention relates to a preparation method of a gradient density resin composite preform and belongs to the technical field of ablation thermal protective materials of hypersonic flight vehicles. Aprepared non-vitrified resin solution and vitrified resin dissolving pulp are paved on quartz fiber woven cloth respectively, a-type micro-vitrified prepreg, b-type micro-vitrified prepreg, c-type micro-vitrified prepreg and d-type micro-vitrified prepreg are prepared respectively after drying, the prepregs are paved in a forming cavity of a paving and stitching tool, and a finished product of the gradient density resin composite is prepared with a vacuum-pumping compacting method. The prepared gradient density material is divided into multiple layer in the aspect of plane composition, all layers of materials are in uniform transition, so that the interface problem is eliminated, the requirements of a thermal protection system of a hypersonic flight vehicle for an anti-ablation and anti-shear surface layer, a low-density and efficient thermal-insulating inner layer and a buffering and transition middle layer are realized, and the requirements of lightweight, low ablation and efficientthermal insulation of the thermal protection system of the hypersonic flight vehicle are met.

The invention discloses a variable-thrust miniature solid rocket motor flexible nozzle system, which belongs to the technical field of aerospace power propulsion devices. It includes a displacement acquisition module, a control module, a flexible nozzle and several servo mechanisms arranged in the circumferential direction of the flexible nozzle; the two ends of the flexible nozzle are respectively fixedly connected with the nozzle contraction section and the nozzle expansion section, and the servo mechanism includes a servo motor, The transmission rod and the transmission sheet, the servo motor is connected with the transmission rod, the transmission rod is connected with the transmission sheet, and the transmission sheet is attached to the outer wall of the flexible nozzle; the displacement acquisition module is used to collect the displacement data of the diameter change of the flexible nozzle. The displacement acquisition module and The servo motors are respectively connected to the control module, and the control module is connected to the upper computer. The invention has a simple and reliable structure, is suitable for a miniature solid rocket motor, and greatly improves the response speed of the thrust change. At the same time, the input and output signals are fed back in real time through the displacement acquisition module and the control module, which improves the control accuracy of the thrust.

The invention discloses an impact-resistant curved bar lattice sandwich plate structure. The curved bar lattice structure is combined with the sandwich plate structure to obtain a light-weight, high-strength, and strong impact-resistant sandwich plate structure. The structure is composed of an upper surface plate, a lower surface plate, and a curved rod lattice structure core layer. The curved rod lattice structure core layer is formed by extending a single curved rod substructure in space, and a single curved rod substructure consists of several shapes The same curved rods are crossed at equal angles. The curved rod lattice structure is light in weight and high in strength. It has good deformation capacity and energy absorption efficiency under impact load, and it has relatively good bending stiffness and impact resistance when combined with the sandwich plate structure. It has broad application prospects in aerospace, civil engineering, machinery manufacturing and other fields.

A handpiece for dental or surgical applications has a chuck for rotatably clamping a tool such as a bur, the chuck being drivingly connectable to a drive mechanism such as to rotate the tool about a rotation axis thereof, a push button operatively connected to the chuck, configured to release the tool from the chuck upon depressing the push button, a spherical element, preferably a ball, fitted within or mounted at the push button, arranged and configured such that, when the push button is depressed, the spherical element enters into contact with the chuck, the spherical element being of a material with a high hardness on the Vickers scale of >2000.

The invention provides a round bamboo molding plate which is formed by hot press by two or more than two round bamboos arranged in a staggered manner end to end. The round bamboos are green bamboos with through bamboo sections. At least one connecting hole is drilled between adjacent round bamboo sections. The adjacent round bamboo sections penetrate through the connecting hole through a connecting rod and are connected in a row. The round bamboo molding plate has the beneficial effects that the utilization rate of moso bamboo is improved by more than 85%, the cost is reduced, pollution is reduced, and the round bamboo molding plate further has strong physical stability and is attractive. As stock boards are formed, the round bamboos are widely used in buildings and level in shape, and reduce the transportation and manual expenses are lowered and the cost performance is improved. With accessories, the round bamboo molding plate can be directly assembled as wattled wall, trestle road along cliff and chairs and the like. With industrialized production capacity, the cost is greatly lowered, the quality is improved and the service life is prolonged, and the service range is expanded, i.e., bamboos with small diameter can be used for producing screens and bamboos with large diameter can be used as ground of the trestle road along cliff.