Abstract: A semiconductor substrate includes a base portion, an auxiliary layer and a surface layer. The auxiliary layer is formed on the base portion. The surface layer is formed on the auxiliary layer. The surface layer is in contact with a first main surface of the semiconductor substrate. The auxiliary layer has a different electrochemical dissolution efficiency than the base portion and the surface layer. At least a portion of the auxiliary layer and at least a portion of the surface layer are converted into a porous structure. Subsequently, an epitaxial layer is formed on the first main surface.

Abstract: A push-bar for doors in general, comprising a bar-like element which is adapted to be applied to one side of a door by means of a pair of couplings; one of the couplings, arranged at an edge of the door that is adapted to abut against the doorjamb, being provided with lever means which are adapted to actuate a latch element which protrudes from the coupling of the bar-like element and is adapted to abut against the doorjamb.

Abstract: On a housing (10) which has a mount (20) for a roll (22) of paper, a roller (30) is mounted, by means of a spindle body (32), beneath said mount. A spring (40) is wound in the form of a coil around the spindle body (32) and, in the event of forwards rotation of the roller (30), is subjected to stressing and rotates said roller into a rest position after the paper web (24) has been severed. An end section (42, 48) of the spring (40) is formed by spring coils which always rest against the spindle body (32) in a close-fitting manner, with the result that they act as a directional lock. Between its end sections (42, 48), the spring (40) has a main part (46) comprising spring coils which, in the non-stressed state, enclose the spindle body (32) with radial spacing, only rest against the spindle body (32) in a close-fitting manner after a predetermined forwards rotation of the roller (30), and consequently prevent further rotation of the roller (30).