PACS: 71.55.Eq; 73.21.La In quantum dot structures, photoionization has been considered as an optical transition from the impurity ground state to the conduction subbands. Using a variational approach, we have calculated the photon energy dependence of the photoionization cross-section for a hydrogenic donor impurity in an infinite barrier GaAs quantum dot as a function of the sizes of the dot and the impurity position. The results we have obtained show that the photoionization cross-section is strongly affected by the quantum size effects and the position of the impurity and its overall shape seems to be a signature of the quantum dot system.

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language. We investigate the changes that must be made to the model to adapt Arabic voice recognition. In this paper we present the creation of an Arabic version ofAutomated Speech Recognition System (ASR). II. SYSTEM PRESENTATION This system is based on the open source Sphinx-4, from Sphinx-4 speech recognition system has been jointly the Carnegie Mellon University. Which is a speech developed by the Caregie Mellon University, Sun recognition system based on discrete hidden Markov models (HMMs). We investigate the changes that must RosemsLaboratories and Itsubish Elt Research Laboratories (M.E.R.L). It has been built be made to the model to adapt Arabic voice recognition. entirely in Java TM programming language. Since the born the Sphinx Group is dedicated to release a set of HMMs: reasonably mature, speech components. Those provide a HMMS, A t basic technology level to anyone interested in creating

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