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The atomic arrangements and electronic structures of [0001] oriented GaN nanowires with different side surfaces have been studied by the first-principles molecular dynamics (MD) method and the conventional first-principles electronic structure calculation method. It is found that due to the dangling bond effects, the Ga-N bonds on the side surfaces of the nanowire tilt with Ga surface atoms moving inward. The radius of the nanowire is found to be reduced with respect to the wire truncated from a bulk GaN solid, which can be attributed to the surface tension effect. Due to the large ratio between the numbers of surface atoms and bulk atoms, the electronic structures of these nanowires are very different from those of bulk and films due to the large number of surface atoms or dangling-bond states, so that a bulk-like energy gap can not be clearly defined.

Structure properties of water clusters are investigated in this study by means of molecular dynamics simulations. The oxygen density profile, dipole moment and hydrogen bond properties of water clusters are all examined. The temperature dependence and size dependence of the structure properties are also explored in the present study. Upon the molecular dynamics simulations, the flexible three-centered (F3C) water potential is used to model the inter- and intra-actions of the water molecule. It is found that as the temperature rises, the density of the oxygen and the average number of hydrogen bonds per water molecule will decrease. The effect of cluster size, however, is less significant on the structure properties. The differences between the structural properties for the surface region and those for the interior region of the cluster are also investigated. It is found that as the temperature rises, the average number of hydrogen bonds per water molecule decreases, but the ratio of surface water molecules increases. After comparing the water densities in interior regions and the average number of hydrogen bonds in those regions, we find there is no apparent size effect on water molecules in the interior region, whereas the size of the water cluster has a significant influence on the behavior of water molecules at the surface region.

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A series of dimolybdenum compounds having a Mo2 4+ core coordinated by various ligands, including formamidinate (e.g. DAniF = N, NN-di-p-ansisylformamidinate ), acetate and/or acetonitrile molecules, have been synthesized as building blocks for the construction of Mo2-containing supramolecular arrays. Compound Mo2(DAniF)3(O2CCH3) was specifically designed for the preparation of dimolybdenum pairs, whereas the others meet the needs of Mo2 4+ units for different geometry settings. Compounds described by a general formula [Mo2]L[Mo2], where [Mo2] = [Mo2(DAniF)3]+, have two dimetal units electronically coupled by the central unit L , which consequently engender significant impact on the redox property and electronic structure of the molecule. It is found that in the weakly coupled complex system, [Mo2]M(OCH3)4[Mo2] (M = Zn and Co), the mixed-valence complexes present asymmetric molecular structures with two distinct [Mo2] units corresponding to be a bond order 4.0 (F2B4*2) and 3.5 (F2B4*1), respectively. EPR and magnetic susceptibility measurements for the doubly oxidized species show that there is no significant antifferromagnetic spin coupling. Electron delocalization occurs in the complex system where a N, N'-dimethyloxamidate binds two [Mo2] units within two fused six-membered rings. In this case, the mixed-valence complex has a symmetric molecular structure, implying that the odd electron is fully delocalized over two [Mo2]units. Strong metal-metal interaction is also evidenced by intervalence charge transfer of the mixed-valence species and the diamanetism of the doubly oxidized complex. Remarkably, two isomers varying in linkage conformation, namely, alpha and beta, have been isolated as diaryloxamidate ligands are used as the linker. Studies on the neutral and the oxidized compounds of the two isomers by employing various techniques consistently show that in the alpha form intramolecular electron transfer is blocked , while in the beta form, the electrons are delocalized over the two [Mo2] units. Thus, the mixed-valence complexes of the two isomers are appropriately described by alpha-[Mo2]0(oxamidate)[Mo2]1+ and beta- [Mo2]0.5+(oxamidate)[Mo2]0.5+ respectively.

<p>In the past, the Swedish bond market has been distinguished for its illiquidity and difficulties with retrieving information. This is the starting point of our thesis and the purpose is to analyze and describe the availability of the present corporate bond market for manufacturing firms in Sweden. In order to fulfill the purpose, a qualitative method was used and interviews with different operators of the market were conducted. Our respondents were sampled from large issuing companies, the major intermediaries and companies that have not tried bonds as a financing tool.</p><p>To fulfill our purpose, we analyzed subjects as credit rating, capital market segmentation, regulations and volume. We came to the conclusion that the Swedish corporate bond market is somewhat underdeveloped. This is due to the lack of public information regarding the bonds, such as prices, outstanding bonds and interest rates.</p><p>The availability for already active companies is good, mainly due to the important role the intermediaries play. The regulations set by authorities do not have great effect on the large companies in general, since they issue large amounts, the cost associated with the regulations do not affect them in a considerable way. One could rather see a positive side with the regulations, for example the increase of foreign issuers that entered the market the last couple of years and hence increasing the liquidity. A credit rating is sometimes beneficial but not always, it is not a necessity to enter the bond market.</p><p>As a matter of fact, it seems like volume is the most important reason to why medium-sized companies have limited access to the market. Since the minimum recommended volume to issue is 50 million SEK, many companies are excluded due to lack of financing need. Another important factor concerning medium-sized companies is that they do not have sufficient experience, knowledge or interest in the bond market. There are probably companies that would like to enter the bond market, who do not have the opportunity to do so, but this do not have anything to do with the lack of credit rating, rather the high cost associated with it.</p><p>The conclusion drawn is that it is hard to compare small and medium-sized companies with large already established actors. This is due to different need of capital and overall knowledge about the debt market.</p>

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 115-120). Also available on the Internet.

Thèse de doctorat : ETUDES ANGLAISES : Metz : 1997. / 1997METZ003L. 373 ref.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 115-120). Also available on the Internet.