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Browsing College of Natural Sciences by Title

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  • Mekete, Antigegn (Addis Ababa University, 2022-04-18)
    In this thesis, we analyze the statistical and squeezing properties of the light produced by a degenerate three-level atom, whose top and bottom levels are coupled by coherent light, and available in a cavity containing ...
  • Mustefa, Ahmed (Addis Ababa,University, 1993-09)
    The semiempirical guantum chemical method cNdo/2 was Proposed to calculate the reactivity indices, Atomic Superdelocalizability,
  • Regassa, Admassu (Addis Ababa Universty, 1990-06)
    The. Ut.le. st.udy w .... unde.r-t.ake.n t.o an e.lablJr-at.e.d clust.e.» mode.l of' silica ge.l and t.o inve.sUgat.e. adso»pt.ion comple.xe.s of pr-ope.ne. wit.h silica using INDO me.t.hod and opt.imizat.ion of geomet.»y. ...
  • Gadisa, Abay (Addis Ababa University, 2000-10)
    In this thesis we investigated the photovoltaic properties of poly [3-(4- octylphenyl)-2, 2'-bithiophene] (PTOPT) in the form of AI/PTOPT/ITO sandwich structure. The peaks of the spectral response of the device were found ...
  • Nigussie Yhunebrhane (Addis Ababa University, 2014-06)
    We consider the behavior of 2D systems in the strong magnetic elds and at low temperature. The main attention is devoted to the quantum Hall e ect in two dimension electron gas and in one layered graphene . The original ...
  • Eticha, Moreda (Addis Ababa University, 2015-10)
    We studied Quantum Hall E ect with and without magnetic eld in graphene. The quan- tum Hall e ect is a quantum-mechanical version of the Hall e ect, observed in graphene, in which the Hall conductance ( H) takes on the ...
  • Achenefe Yohannes (Addis Ababa University, 2009-06)
    In this work we analyze the modern state of the problem connected with quantum Hall effect (integral and fractional). The quantum Hall effect is a quantum-mechanical version of the Hall effect, observed in two dimensional ...
  • Mengesha, Menberu (Addis Ababa University, 2012-06)
    In this dissertation the energy of the ground and excited state of symmetric and asymmetric parabolic double quantum wells (DQWs) are investigated by using our formulated trial wave functions and the Hamiltonian. For ...
  • Alemayu, Ataklti (Addis Ababa University, 2018-06-07)
    In this work, we investigate quasi Newton methods for solving unconstrained optimization problems. We consider two di erent quasi-Newton update formulas, namely, Broyden- Fletcher-Goldfarb and shanno (BFGS) update and ...
  • Balew, Haimanot (Addis Ababa University, 2012-01)
    In spite of the fact that the origin of non-smooth optimization as a mathematical discipline is quite recent; it is now well established as an important and very active branch of applied mathematics. Many practical ...
  • Fentie Abebe (Addis Ababa University, 2009-10)
    The microscopic theory of the low temperature superconductivity is reviewed along with the mechanism of electron-electron interaction. We have investigated the electrical and magnetic properties of superconductors. Our ...
  • Indris, Anwar (Addis Ababa University, 2015-10)
    today’s information world there are various mechanisms of electronically searching for information. Keyword based searching is one of the popular searching mechanism in web documents as well as database systems. A lot of ...
  • Zeray, Tsadu (Addis Ababa University, 2017-10-04)
    This research has been prepared to enhance the precision and recall of Tigrigna IR system by integrating query expansion mechanism. Query expansion is an effective mechanism to control the effect of polysemous and synonymous ...
  • Geleta, Seifu (Addis Ababa University, 2004-06)
    The goal of query optimization is to select an efficient query evaluation strategy. Query optimization is a widely studied problem in the context of traditional database systems. As a result many query optimization ...
  • Bayisa, Asefa (Addis Ababa University, 2015-03)
    Text summarization is the most challenging task in information retrieval. It is an outcome of electronic document explosion and can be seen as the condensation of the document collection. Automatic text summarization can ...
  • Simie, Hiruy (Addis Ababa University, 2007-06)
    This thesis has attempted to examine the various factors causing deforestation in and around Mt. Zeqwala. It further tries to identify the change that occurred in the diminishing area of the forest used to cover and the ...
  • Teka, Haftu (Addis Ababa University, 2011-06)
    We construct a quotient group by fuzzy normal subgroup and we prove the corresponding Isomorphism Theorems. Obtained results are used to the characterization of selected classes of quotient groups
  • Lakew Zenebe (Addis Ababa University, 2016-07)
    Certain techniques fundamental to the study of algebra. One of such techniques is the construction of a quotient set of an algebraic structure by a means of an equivalence relation on the given set. Based on this, we ...
  • Demissie, Driba (Addis Ababa University, 2001-06)
    We present a detailed derivation of the equations of evolution for the reduced density operators (or the master equations) of coherently driven degenerate and nondegenerate three-level lasers. Employing these equations ...

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