(In this respect, bremsstrahlung differs from Cherenkov radiation, another kind of braking radiation which occurs only in matter, and not in a vacuum.)
（在这方面，轫致辐射不同于切伦科夫辐射，切伦科夫辐射是另外一种制动辐射,只发生在物质中，而不是在真空中进行。