3 resultados para Quasi-periodic

em Coffee Science - Universidade Federal de Lavras


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The development of cost-effective and reliable methods for the synthesis and separation of asymmetric compounds is paramount in helping to meet society’s ever-growing demand for chiral small molecules. Of these methods, chiral heterogeneous supports are particularly appealing as they allow for the reuse of the chiral source. One such support, based on the synergy between chiral organic units and structurally stable inorganic silicon scaffolds are periodic mesoporous organosilicas (PMOs). In the work described herein, I examine some of the factors governing the transmission of chirality between chiral dopants and prochiral bulk phases in chiral PMO materials. In particular, the exploration of 1,1’-binaphthalene-bridged chiral dopants with a focus on the point of attachment into the materials. Moreover, the effects of ordering in the materials are examined and reveal that chirality transfer is more facile in materials with molecular-scale order then those containing amorphous walls. Secondly, the issues surrounding the synthesis and purification of aryl-triethoxysilanes as siloxane precursors are addressed. Both the introduction of a two-carbon linker and the direct attachment of allyl and mixed allyldiethoxysilane species are explored. This work demonstrates that allyldiethoxysilanes are ideal, in that they are stable enough to permit facile synthesis, while still being able to hydrolyze completely to produce well-ordered materials. Lastly, the production of new bulk phases for chiral PMO materials is examined by introducing new prochiral nitrogen-containing siloxane precursors. Biphenyldiamine and bipyridine-bridged siloxane precursors are readily synthesized on reasonable scales. Their use as the bulk siloxane precursor in the production of PMO materials however, is precluded by insufficient gelation and additional siloxane precursors are necessary for the production of ordered materials. In addition to the research detailed above that forms the body of this thesis, two short works are appended. The first details the production of polythiophene assemblies mediated through coordination nanospaces, while the second explores the production of N-heterocyclic carbene functionalized gold nanoparticles through ligand exchange.

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The purpose of this paper is to derive the dynamical equations for the period vectors of a periodic system under constant external stress. The explicit starting point is Newton’s second law applied to halves of the system. Later statistics over indistinguishable translated states and forces associated with transport of momentum are applied to the resulting dynamical equations. In the final expressions, the period vectors are driven by the imbalance between internal and external stresses. The internal stress is shown to have both full interaction and kinetic-energy terms.

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A number of laws in Canada which uphold rights are referred to as quasi-constitutional by the courts in recognition of their special importance. Quasi-constitutional statutes are enacted through the regular legislative process, although they are being interpreted and applied in a fashion which has become remarkably similar to constitutional law, and are therefore having an important affect over other legislation. Quasi-constitutionality has surprisingly received limited scholarly attention, and very few serious attempts at explaining its significance have been made. This dissertation undertakes a comprehensive study of quasi-constitutionality which considers its theoretical basis, its interpretation and legal significance, as well as its similarities to comparable forms of law in other Commonwealth jurisdictions. Part I examines the theoretical basis of quasi-constitutionality and its relationship to the Constitution. As a statutory and common law form of fundamental law, quasi-constitutionality is shown to signify an association with the Canadian Constitution and the foundational principles that underpin it. Part II proceeds to consider the special rules of interpretation applied to quasi-constitutional legislation, the basis of this interpretative approach, and the connection between the interpretation of similar provisions in quasi-constitutional legislation and the Constitution. As a statutory form of fundamental law, quasi-constitutional legislation is given a broad, liberal and purposive interpretation which significantly expands the rights which they protect. The theoretical basis of this approach is found in both the fundamental nature of the rights upheld by quasi-constitutional legislation as well as legislative intent. Part III explores how quasi-constitutional statutes affect the interpretation of regular legislation and how they are used for the purposes of judicial review. Quasi-constitutional legislation has a significant influence over regular statutes in the interpretative exercise, which in some instances results in conflicting statutes being declared inoperable. The basis of this form of judicial review is demonstrated to be rooted in statutory interpretation, and as such it provides an interesting model of rights protection and judicial review that is not conflated to constitutional and judicial supremacy.