The invention provides a method of preparing hydrophobic silica particles comprising providing an aqueous colloidal silica dispersion comprising about 5-70 wt. In order to achieve the object, radio resources are assigned in different orders between one radio communication and another one radio communication. Apart from \u201cclassical\u201d microphones, microphones are also used in headsets, and frequently microphones are accommodated by mounts, e. The holders of the pair of gear train units are symmetrical with respect to a surface perpendicular to the pair of axles and joined to each other through the surface, and integrally fitted together in the bull common gear. The front and rear wheels are held by pivoting forks that can be selectively moved from an operational position to a closed position in the closed position, the front wheel is disposed in the first storage space and the rear wheel is disposed in the second storage space.