Definition: Translate the given Spanish text to English

Positive Example 1 -
Input: A method for converting a series of m-bit information words to a modulated signal is described.
Output: Se describe un método para convertir una serie de palabras de informacion de bits m a una señal modulada.

Positive Example 2 -
Input: A last plastic cover is applied as a final protection.
Output: La presente invencion comprende un nuevo mezclador termocinetico.

Negative Example 1 -
Input: Luminescent optical sensor.
Output: SENSOR OPTICO LUMINISCENTE.

Negative Example 2 -
Input: The urinal is similar to a common toilet.
Output: El común es similar a un inodoro orinal.

Now complete the following example -
Input: A process for the alkylation of aliphatic hydrocarbons with olefins catalyzed by a silica-based material, characterised in that the surface Si-OH groups of said silica are esterified with a fluoroalkylsulphonic acid of formula CF3(CF2)nSO3H, where n is a whole number between 0 and 11, said material having a Hammett acidity Ho</=-11.4.
Output: Un procedimiento para alquilacion de hidrocarburos alifaticos con olefinas catalizas con un material a base de silica, caracterizado porque los grupos superficiales Si-OH de esa silica se esterifican con acido fluoroalquilsulfonico de la formula CF3(F2)nSO3H, en donde n es un numero entero entre 0 y 11, el material tiene un acidez Hammett Ho-11.4.