The plasma jet: industrial hygiene aspects and a survey of current United States practices for employee protection.
Abstract The plasma torch, because it concentrates large amounts of thermal energy in a small volume, has become increasingly popular in industry. During the past fifteen years, the plasma torch has developed into an important industrial tool, and it has been used for metal cutting and welding fabricating operations that would not be possible otherwise. However, along with technological advances, the plasma torch has presented new problems to the industrial hygiene field. It is the purpose of this paper to discuss these problems and the extent of industrial hygienist's awareness of them. A brief outline of the theory of the plasma torch and the history and scope of its industrial usage is also presented.
Plasma Spraying Techniques for Toxic and Oxidizable Materials
Plasma spraying has made it possible to deposit materials which were heretofore considered as unsprayable. Two categories of materials are discussed—materials which have a toxicity problem associated with their handling, and those which undergo rapid oxidation and composition changes when sprayed in air.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.