Abstract: An invert emulsion having double particle size distribution, the invert emulsion having a particle size distribution of latex particles between 20 nm and 70 nm and between 100 nm and 500 nm in the same invert emulsion system. A preparation method for an invert emulsion comprises: forming an emulsion A and an emulsion B having different particle sizes by controlling an emulsifier system and an emulsification means, and preparing in one step an invert emulsion the particle size of which has bimodal distribution by means of a three-stage polymerization reaction between the emulsion A and the emulsion B in the same system. The invert emulsion is used as a water treatment flocculant, a sludge dewatering agent and a papermaking auxiliary agent, and in particular, the sludge dewatering agent fabricated from the invert emulsion is used for dewatering sludge.

Abstract: A cryogenic engine for a space apparatus is provided. The cryogenic engine includes an injector body, a thrust chamber, and a spark plug, where the injector body is provided therein with an accommodating space; the spark plug is provided on one side of the injector body, and an electrode provided on the spark plug extends into the accommodating space; the thrust chamber is provided on the other side of the injector body and is communicated with the accommodating space; the injector body is provided with a combustion improver flow channel and a combustible agent flow channel; and the combustion improver flow channel and combustible agent flow channel are connected with the accommodating space.