Radiative Recombination at Dislocations in Germanium -- I. Experimental Method -- II. Radiative Recombination in Germanium Crystals with Dislocation Densities of 103104 cm-2 -- III. Radiative Recombination in Germanium Crystals with High (105-106 cm-2) Dislocation Densities. Radiative Recombination Mechanism -- IV. Determination of the Quantum Yield of the Recombination Radiation Associated with Dislocations -- Conclusions -- Literature Cited -- Impact Ionization of Impurities in Germanium at Low Temperatures -- I. Impact Ionization (Review) -- II. Experimental Technique -- III. Results of Measurements and Discussion -- IV. Breakdown -- V. Influence of a Magnetic Field on the Electrical Conductivity of Germanium in Prebreakdown and Breakdown Fields -- VI. Electrical Conductivity of Germanium in Fields Higher than the Breakdown Value -- VII. Electrical Discharge in Very Thin Germanium Layers at Low Temperatures -- Appendix. Electrical Conductivity of Zinc-Doped Germanium -- Literature Cited -- Investigation of the Infrared Absorption Spectrum of Neutron-Irradiated Silicon -- I. Effects of Radiations on a Semiconducting Crystal. Review of the Main Papers on Radiation Defects in Silicon -- II. Experimental Method -- III. Experimental Results and Discussion -- Conclusions -- Literature Cited -- Electrical and Optical Properties of Electroluminescent Capacitors Based on ZnS:Cu -- I. Principal Mechanism of Electroluminescence -- II. Experimental Method -- III. Frequency Characteristics of an Electroluminescent Capacitor -- IV. Dependence of the Characteristics of an Electroluminescent Capacitor on Voltage -- V. Rectification of the Current by an Electroluminescent Capacitor -- Conclusions -- Literature Cited.