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Full-Text Articles in Computational Engineering
Ab Initio Studies Of Proton Transport In Proton Exchange Membranes, Jeffrey Keith Clark
Ab Initio Studies Of Proton Transport In Proton Exchange Membranes, Jeffrey Keith Clark
Doctoral Dissertations
A molecular-level understanding of the factors that contribute to transport properties of proton exchange membranes (PEMs) for fuel cell applications is needed to aid in the development of superior membrane materials. Ab initio electronic structure calculations were undertaken on various PEM ionomer fragments to explore the effects of local hydration, side chain connectivity, protogenic group separation, and specific side chain chemistry on proton dissociation and transfer at low hydration. Cooperative interactions between both intra- and inter-molecular acidic groups and hydrogen bond connectivity were found to enhance proton dissociation at very low degrees of hydration. The energetics associated with proton transfer …
Calculation And Experimental Verification Of Longitudinal Spatial Hole Burning In High-Power Semiconductor Lasers, Ting Hao
Graduate Theses - Physics and Optical Engineering
Longitudinal spatial hole burning (LSHB) is believed to be one of the limiting factors in scaling the output power of high-power semiconductor lasers. In this work, a self-consistent simulation of LSHB was performed to investigate the non-uniform longitudinal photon density distribution, carrier density distribution, and gain distribution in a high-power semiconductor laser. The calculation is based on a modification to the semiconductor laser rate equations and solved using a finite difference approach, with Newton’s method employed to numerically solve the differential equations. The impact of LSHB on output power was analyzed with different parameters, including injection current, cavity length, and …