Abstract: The invention belongs to the field of catalysts, and particularly relates to a composite oxide containing tungstate nanoclusters, and a preparation method and application thereof. The tungstate nanocluster-containing composite oxide comprises an alkali metal element A, a tungsten element W, an auxiliary agent element M, and an oxygen element O, wherein the alkali metal element A, the tungsten element W and the auxiliary agent element M form a composite with the oxygen element O. The composite oxide as a cocatalyst can obviously improve the selectivity and the yield of C2 in the oxidative coupling of methane reaction with co-fed methane and oxygen.

Abstract: This invention introduces the negative feedback into the gate drive. It proposes a negative feedback active gate drive (NFAGD) for silicon carbide (SiC) and gallium nitride (GaN) semiconductor devices to fully utilize their potential of high switching-speed capability in a phase-leg configuration. An auxiliary P-channel MOSFET is introduced to construct a negative feedback control mechanism. Due to the negative feedback mechanism, the proposed drive can automatically attenuate the disturbance from the complementary device of the phase-leg. The negative feedback active gate drive (NFAGD) has a simple structure and easy to be realized using a push-pull drive circuit, a drive resistor, an auxiliary MOSFET and an auxiliary capacitor, without involving any additional logical circuits.

Abstract: This invention introduces the negative feedback into the gate drive. It proposes a negative feedback active gate drive (NFAGD) for silicon carbide (SiC) and gallium nitride (GaN) semiconductor devices to fully utilize their potential of high switching-speed capability in a phase-leg configuration. An auxiliary P-channel MOSFET is introduced to construct a negative feedback control mechanism. Due to the negative feedback mechanism, the proposed drive can automatically attenuate the disturbance from the complementary device of the phase-leg. The negative feedback active gate drive (NFAGD) has a simple structure and easy to be realized using a push-pull drive circuit, a drive resistor, an auxiliary MOSFET and an auxiliary capacitor, without involving any additional logical circuits.

Abstract: The present invention discloses a concrete structure used for bank protection and scour prevention of river bank and coast. Its construct is a hollow circular truncated cone and concrete flat plates are plugged on the hollow circular truncated cone. By tearing, dispersing and stirring up water flow, the energy of local water flow is dissipated, and the scouring strength of the water flow is weakened, achieving the aim of scour prevention and bank protection. It has good mechanical property, not easy to be destroyed, has good stability in water and big overhead rate, and can save materials. Compared to previous various structures for scour prevention, the present invention has better effects of energy dissipation and scour prevention. It not only can be used in bank protection and scour prevention, but also can be used for supplementary energy dissipation when plugging and closure.

Abstract: The present invention discloses a readjustment-preventing carburetor and a method for preventing the carburetor from being readjusted. The carburetor includes an idle adjusting screw having a concave neck, an idle port and a screw hole communicating with the idle port. The idle adjusting screw is joined with the screw hole as a whole after being adjusted to a certain position, and any further adjustment will cause the concave neck to be broken off to prevent the idle adjusting screw of the carburetor from being readjusted. Additionally, the idle adjusting screw is joined with the screw hole by bonding or welding, thereby fundamentally preventing anyone from readjusting the idle adjusting screw of the carburetor and ensuring the discharge of the gasoline engine always in conformity with the requirements of environmental protection. The carburetor and the method of the present invention have the characteristics of simple process and structure, safety use and reliability.

Abstract: The present invention discloses a readjustment-preventing carburetor and a method for preventing the carburetor from being readjusted. Said carburetor comprises an idle adjusting screw, an idle port and a screw hole communicating with the idle port, wherein said idle adjusting screw is consolidated with said screw hole as a whole after being adjusted to a certain position, so as to prevent the idle adjusting screw of the carburetor from being readjusted. The consolidation of the present invention can be bonding or welding, thereby fundamentally preventing the user from readjusting the idle adjusting screw of the carburetor and ensuring the discharge of the gasoline engine always in conformity with the requirements of environmental protection. The carburetor and the method of the present invention have the characteristics of simple process and structure, safety use and reliability.