Abstract: The present invention discloses an impedance matching circuit and method. The circuit is applied to a power supply circuit of an envelope tracking radio frequency power amplifier. An envelope tracking power supply is connected with a radio frequency power amplifier through a first matching circuit. The envelope tracking radio frequency power amplifier obtains the optimal efficiency by performing matching according to an optimal efficiency load impedance of the envelope tracking power supply and a conjugate impedance of an optimal efficiency load impedance of the radio frequency power amplifier.

Abstract: The present invention relates to a high-temperature resistant modified silicon-containing cyanate ester resin as well as a preparation method and an application thereof. The preparation method comprises the following steps: adding a mixed solution of hydroxyl silicone oil, a silane coupling agent and an organic solvent into a mixed solution of a tetramethylammonium hydroxide aqueous solution and a polar solvent, performing hydrolytic polycondensation at a temperature of 5-40° C. for 4-8 h, and performing distillation to obtain an epoxy-containing silsesquioxane; performing pre-polymerization on the epoxy-containing silsesquioxane and a cyanate ester resin at a temperature of 50-100° C. for 1-8 h to obtain a modified cyanate ester resin; and uniformly mixing the modified cyanate ester resin and a modified anhydride, thereby obtaining the high-temperature resistant modified silicon-containing cyanate ester resin.

Abstract: The present invention belongs to the technical field of polishing machinery, and particularly relates to a full-automatic polishing machine aiming at the valve core head of a snort valve. The full-automatic polishing machine comprises a base, and a material taking device, a fixture and a polishing device which are provided on the base, wherein the material taking device comprises mechanical arms, and a first driving mechanism for driving the mechanical arms to move in transverse and vertical directions; and the polishing device comprises a grinding wheel, a second driving mechanism for driving the grinding wheel to rotate, and a third driving mechanism for driving the grinding wheel to move in longitudinal and vertical directions.

Abstract: A method comprising: A. forming a consortium blockchain network using domain network nodes and selecting committee members from top-level domain nodes; B. the committee member who received most votes packs the genesis block and generates a random number; C. the housekeeper having the same number as the random number packs the current block and generates a random number for selecting a next housekeeper to pack the next block, each block is approved by more than half of the committee members; D. during the duty cycle, each housekeeper takes turns packing blocks and generating random numbers and the process is repeated. If a block is not approved, the housekeeper with the next number is requested to repack the block; and E. the last random number generated by a housekeeper before the duty cycle ends is used to select the housekeeper to pack the first block of the next duty cycle.

Abstract: A polyoxazolidinone resin, a preparation method thereof and a use thereof in an impregnating varnish are provided. The polyoxazolidinone resin is prepared by reacting an alicyclic epoxy resin and a diisocyanate in the presence of a catalyst at 150° C. to 170° C. for 3 to 5 hours, wherein the molar ratio of the isocyanate radical in the diisocyanate to the epoxy radical in the alicyclic epoxy resin is 1:1.8 to 2.3. the impregnating varnish of the present invention uses the polyoxazolidinone resin as a bulk material in combination with acrylated epoxy resin and alicyclic epoxy resin, such that the impregnating varnish has the advantages of being heat resistant and flame retardant, low in cost, and eco-friendly, and finds use in insulation treatment of high-voltage and low-voltage electric machinery.

Abstract: The present invention relates to a high-temperature resistant modified silicon-containing cyanate ester resin as well as a preparation method and an application thereof. The preparation method comprises the following steps: adding a mixed solution of hydroxyl silicone oil, a silane coupling agent and an organic solvent into a mixed solution of a tetramethylammonium hydroxide aqueous solution and a polar solvent, performing hydrolytic polycondensation at a temperature of 5-40° C. for 4-8 h, and performing distillation to obtain an epoxy-containing silsesquioxane; performing pre-polymerization on the epoxy-containing silsesquioxane and a cyanate ester resin at a temperature of 50-100° C. for 1-8 h to obtain a modified cyanate ester resin; and uniformly mixing the modified cyanate ester resin and a modified anhydride, thereby obtaining the high-temperature resistant modified silicon-containing cyanate ester resin.

Abstract: An electronic device that is operable to provide navigation information to a user by utilizing the navigation system of a separate mobile device, such as a GPS-enabled mobile phone. The electronic device includes a communication interface for communicating navigation data between the mobile device and the electronic device. The electronic device also includes a display for displaying the navigation data received from the mobile device. The display of the electronic device may be larger than the display of the mobile device, such that a driver of an automobile may use the electronic device to provide a more desirable viewing experience. Further, the electronic device may include a user interface, such as a touch screen, that allows a user to access and control the navigation functions of the mobile device. The electronic device may also be operable to communicate with other portable electronic devices.

Abstract: An electronic device that is operable to provide navigation information to a user by utilizing the navigation system of a separate mobile device, such as a GPS-enabled mobile phone. The electronic device includes a communication interface for communicating navigation data between the mobile device and the electronic device. The electronic device also includes a display for displaying the navigation data received from the mobile device. The display of the electronic device may be larger than the display of the mobile device, such that a driver of an automobile may use the electronic device to provide a more desirable viewing experience. Further, the electronic device may include a user interface, such as a touch screen, that allows a user to access and control the navigation functions of the mobile device. The electronic device may also be operable to communicate with other portable electronic devices.