57results about How to "Low coefficient of thermal expansion" patented technology

The invention discloses a thermosetting resin composition for an integrated circuit. The thermosetting resin composition comprises (a) 10-60 parts of an allyl modified bismaleimide resin prepolymer, (b) 10-40 parts of an anhydride compound, (c) 10-50 parts of benzoxazine resin, (d) 5-50 parts of epoxy resin, (e) 5-50 parts of a fire retardant, (f) 0-5 parts of a curing accelerator and (g) 0-35 parts of inorganic stuffing, wherein the number-average molecular weight of the allyl modified bismaleimide resin prepolymer is 1500-8000 g / mol. The resin composition provided by the invention keeps high heat resistance and high Tg characteristic of the allyl modified bismaleimide resin prepolymer, and achieves UL94V-0 level in halogen-free flame retardant aspect on the basis of low phosphorus content, and simultaneously, has low dielectric constant of the anhydride; and therefore, the resin composition is capable of meeting the requirements of the production process of high-performance printed circuit boards such as a high-density interconnected integrated circuit package.

The invention provides a multistage synchronous lifting device based on carbon fiber barrels. Lifting power is provided by multiple stages of sleeve type stepped lead screws, torque is transferred among the lead screws through internal and external splines adopted for the lead screws, a main body supporting barrel is made from carbon fiber materials, a guide rail structure is embedded into the main body supporting barrel in the circumferential direction, lifting rather than rotation of carbon fibers is achieved through a guide assembly through the cooperation of the guide rail structure and aguide assembly installed on the previous stage of carbon fiber barrel, and therefore torque transferred to lead screw nuts when the lead screws ascend and descend is eliminated. A motor is adopted todrive a worm wheel and a worm to achieve holding and looseness of a holding ring of a locking mechanism, and sensing value changes of a pressure sensor are adopted as feedback signals to automaticallycontrol holding and looseness of the holding ring. The bottom of each stage of lifting barrel is provided with a guide assembly to be matched with the inner wall of the next carbon fiber barrel, a guide ring is installed inside a holding ring installed on the next carbon fiber barrel to be matched with the outer wall of the corresponding lifting barrel, and two-stage guide for lifting of the corresponding carbon fiber barrel is achieved. In the whole device, the motor is adopted to drive a worm gear reducer for driving, and the whole device has the advantages of being good in stability, low in heat expansion coefficient, automatic in lifting, free of disassembly and assembly and convenient to transport.

The invention relates to a synthetic method for a duplex nanometer fuel cell cathode material which has characteristics in including steps as follows: (1) confecting soluble salt solution according with required confecting rate for synthetic cathode material; (2) confecting complexing agent solution using edta, citric acid as main raw material; (3) mixing the solution obtained by the steps (1) and (2), adding suitable ethylene glycol, heating and beating in constant temperature, then obtaining sol; (4) drying obtained sol in drying box, and obtaining gel; (5) processing obtained gel, and changing particle specific surface size, then synthesis the duplex nanometer cell cathode material under given temperature. The method has advantages in that: synthetic method is simple, reaction temperature is lower than solid phase method, nanometer particle is mechanical mixed simply different from duplex, and has better uniformity on microcosmic interface, and is favorable for improving cathode material property.

The invention discloses a gradient-boron-doped diamond strengthened metal matrix composite and a preparation method and application thereof. The composite includes gradient-boron-doped diamond strengthened bodies, and metal matrices, and the gradient-boron-doped diamond strengthened bodies include diamond strengthened bodies, and gradient-boron-doped diamond modified layers arranged on the surfaces of the diamond strengthened bodies. The configuration of the diamond strengthened bodies include one or more of a zero-dimensional particle configuration, a one-dimensional linear configuration, a two-dimensional piece-shaped configuration, and a three-dimensional continuous network skeleton configuration. The coupling of the gradient-boron-doped diamond strengthened bodies with different dimensions can greatly improve the mass of diamonds on the composite, and improve the heat conductivity. In addition, according to the added gradient-boron-doped diamond strengthened bodies, the gradient-boron-doped diamond modified layers account for less, so that the heat conductivity of the diamonds can not be affected, and the humidity between the diamonds and metal can be greatly improved.