超燃冲压发动机的缺点是在静止状态下不能自行启动，所以可以使用多组并联的进气阀，静止状态下用常规阀门，等飞行器速度接近高超音速飞行阶段就关闭常规阀门，这样只使用特斯拉阀来获得氧气。
The disadvantage of a scramjet engine is that it cannot start on its own in a stationary state, so multiple sets of parallel intake valves can be used. In a stationary state, conventional valves can be used. When the aircraft speed approaches hypersonic flight, the conventional valves can be closed, and only Tesla valves can be used to obtain oxygen.

Today.... I asked the kids "What happened to each duckling that did not come back?"
The first class[鲜花][心][抱一抱]answered "Maybe the duck slept somewhere and forgot to go home", "Maybe they were eaten by the frog, the fox and other animals"
The second class was really the cutest❤️❤️❤️
They answered "The duck is behind you" "the duck went to my house and sleep" "The duck is now here in my tummy...I ate the duck"(2x)....
I love their answers.... It means that their comprehension, imagination and reasoning skills are being honed slowly but surely they will grow smart

一个新兴的科技企业，成立时间不长，却做到了很多企业做不到的成绩!这个品牌就是徕芬,凭借高速吹风机起家,在这短短两到三年的时间,迅速被大众所知,打出了不错的成绩。

An emerging technology enterprise has not been established for a long time, but it has achieved many achievements that enterprises can not do! This brand is Leifen, with high-speed hair dryer started, in this short period of two to three years, quickly known to the public, hit a good result.