Absorption Spectrum of γ-Irradiated Lead Silicate Glass
IN an earlier communication1 it was stated that the absorption spectrum of γ-irradiated lead silicate glass showed three absorption bands at 1.7 eV., 2.3 eV. and 3.3 eV. respectively. The separation of the spectral curve into these bands was obtained by assuming that the peak at 3.3 eV. was uninfluenced by the presence of any other bands. The points in the vicinity of this peak were used to estimate the first Gaussian and the other bands were obtained by successive subtraction.
Interaction between High Energy Radiation and Glasses
Effects of high energy radiation depend upon the dominance of particle radiation, primarily manifested in structural changes, or ionizing electronic changes; in practice radiations and damages are mixed. Neutron fluxes of 102 0nvt significantly alter crystalline and vitreous silica. High intensity y and x irradiation induces impurity and intrinsic color and spin centers in silica and complex oxide glasses, which can he differentiated and described in considerable detail. Induced changes can he used to prevent discoloration or, conversely, to read dosage. Such changes include absorption, luminescence and thermoluminescence. Space charges can lead to fracture when surfaces are violated. The understanding and use of other changes are in their infancy. Relatively low energy (light) in high intensity can cause mechanical damage. Thresholds are crucial in modem laser technology.
The power of negativity : selected writings on the dialectic in Hegel and Marx
Part 1 The Philosophic Moment of Marxist-Humanism Part 2 Studies in Hegalian and Marxian Dialectics, 1956-63 Part 3 Theory and Practice at a Turning Point, 1964-71 Part 4 After Philosophy and Revolution: Hegel's Absolutes and Marx's Humanism, 1972-81 Part 5 The Changed World and the Need for Philosophic New Beginnings, 1982-87