Abstract: The invention relates to methods and systems for selectively controlling network selection in an area covered by at least two mobile communication networks. According to the first method, the area which is to be covered is divided up into zones and a specific code is allocated to each individual zone. Said codes are stored in a storage system and the network is selected on the basis thereof. Alternately, a correlation is made between information on a subscriber identification module (SIM) and signals from a cell broadcast channel which is used to select the network.

Abstract: The invention pertains to a method for reaching subscribers in a radio communication system in which an object identification is temporarily assigned to the subscribers. The temporary object identifications are formed by subscriber data sets that respectively define a complete subscriber environment of a virtual communication network VP within the radio communication system, wherein one or more of such subscriber data sets can be assigned to subscribers of the communication system.

Abstract: The invention relates to methods and systems for selectively controlling network selection in an area covered by at least two mobile communication networks. According to the first method, the area which is to be covered is divided up into zones and a specific code is allocated to each individual zone. Said codes are stored in a storage system and the network is selected on the basis thereof. Alternately, a correlation is made between information on a subscriber identification module (SIM) and signals from a cell broadcast channel which is used to select the network.

Abstract: A new high energy chemical complex is provided formed from metastable hel fixed on ammonia (HE.sub.m NH.sub.3), so that the metastable helium electron is captured so as to be held in the "L" layer of the metastable helium atom.The process for producing the He.sub.m NH.sub.3 complex comprises the following steps: excitation of helium to create metastable helium; deposition of metastable helium on NH.sub.3 to form the complex; and accumulation or condensation of the product.The invention finds a particular application as a propellant in the aerospace field.

Abstract: A gas leakage detection apparatus is described comprising a mass spectrometer with which there is associated a first pumping device for creating a relative vacuum in the apparatus, a selective pumping device having a first pumping speed for air and a second pumping speed for the gas which is to be analyzed, said second pumping speed being lower than the said first pumping speed, and a throttling device connected between the selective pumping device and the first pumping device, this throttling device having an opening chosen so as to let through a flow which is very small compared with the flow produced by the selective pumping device for the air.