Desirable properties of manganese zinc ferrites are obtained without the need for controlling or changing the oxygen partial pressure during the sintering and cooling steps by adding a small amount of germanium or gallium to the ferrite and using an atmosphere, such as air, during the sintering and cooling steps, that has at least 1 percent oxygen by volume.
An inductive component includes a core being formed of high-permeability MnZn ferrites having a secondary permeability maximum at a temperature <0.degree. C. Electrically insulating material encapsulates the core.
Security paper with luminescing authenticity characteristics which after excitation with invisible light emit exclusively invisible light of different wavelengths as authenticity signal. The luminophores can be included in the printing ink used or they can be added to the paper material in the manufacture of the paper material. A corresponding test apparatus makes it possible to check the authenticity of the security paper in the presence of customers but unnoticed by them; thereby the invisibility of the test signal and the authenticity signal are taken advantage of and the test device is hidden behind a plate non-transmissive for visible light which however is transmissive for the test signal and for the authenticity signal.
4452843 - Security paper - Owned by GAO Gesellschaft fur Automation und Organisation mbH. (Munich,DE)
Security papers with luminescing authenticity characteristics built in or printed thereon which absorb in the visible region of the optical spectrum but in the infrared have a transparent region in which the luminophore also emits. By the absorption in the visible undesired parasitic emissions are suppressed which would make the luminophore visually evident on corresponding excitation. For testing the authenticity of the document the emission is investigated in the infrared. Suitable luminophores are rare earth metal luminophores in suitable host lattices, particularly in ferrite lattices or garnet lattices, which contain transition metal ions as absorbing elements.
A particle-optical apparatus is proposed as well as a method for operating the same. The particle-optical apparatus provides a magnetic field for deflecting charged particles of a beam of charged particles and comprises a body of a material with a permeability number around which a current conductor at least partially engages and a temperature-adjusting unit for adjusting a temperature of the magnetic-flux-carrying body substantially to a nominal temperature. A relative variation of the permeability number relative to a width of a temperature range is to be smaller than a limit value a, wherein a is preferably smaller than 3.multidot.10.sup.-3 K.sup.-1. In particular, the nominal temperature is at an extremum of a temperature dependence of the permeability number. Preferably, such a particle-optical apparatus can be employed in a microscopy or a lithography apparatus.
Security paper with luminescing authenticity characteristics which after excitation with invisible light emit exclusively invisible light of different wavelengths as authenticity signal. The luminophores can be included in the printing ink used or they can be added to the paper material in the manufacture of the paper material. A corresponding test apparatus makes it possible to check the authenticity of the security paper in the presence of customers but unnoticed by them; thereby the invisibility of the test signal and the authenticity signal are taken advantage of and the test device is hidden behind a plate non-transmissive for visible light which however is transmissive for the test signal and for the authenticity signal.
