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Metastable particles

The emission methods of EEP detection are based on the ability of some metastable particles (N2(A ZJ, metastable atoms of rare gases) to knock electrons out of the surface of metals [59]. The present-day technique of measuring small currents allows one to record any small fluxes... [Pg.295]

Most of the known particles are unstable. For a particle with the mass m the particle physics time scale is t 1/m, so in particle world we refer to particles with lifetime r 1/m as to metastable. To be of cosmological significance metastable particle should survive after the temperature of the Universe T fell down below 7 m, what means that the particle lifetime should exceed t ... [Pg.74]

It is worth noting that the transformation can be induced any time the hydrostatic constraint of the matrix on the metastable particles is relaxed. For example, it is now well established that compressive surface layers are developed as a result of the spontaneous transformation. The process is shown schematically in Fig. 11.18. The fracture strength can be almost doubled by simply abrading the surface, since surface grinding has been shown to be an effective method for inducing the transformation. Practically this is important, because we now have a ceramic that, in principle, becomes stronger as it is handled and small scratches are introduced on its surface. [Pg.385]

A is a constant with a value close to unity, Vzirc is the volume fraction of the metastable particles, Et is the volume strain accompanying the transformation, Em is Young s modulus of the matrix (often alumina), and w is the width of the process zone around a crack containing transformed particles (shown in Figure 18.22). [Pg.337]


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See also in sourсe #XX -- [ Pg.29 ]




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