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Entropy and Escape of Mass in Non-Compact Homogeneous SpacesKadyrov, Shirali 30 July 2010 (has links)
No description available.
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Coordination Chemistry of Bis(diphenylphosphino)amine Ligands with Cobalt Carbonyl and the Intermolecular Catalyzed Pauson-Khand ReactionMerrill, James Malcolm 11 January 2002 (has links)
Bis(diphenylphosphino)amine (PNP) ligands, prepared from (S)-(-)-1-methylbenzyl amine, (-)-cis-myrtanylamine, (S)-(-)-1,1-napthyl(ethyl)amine (PNP1 1a, PNP2 1b, and PNP3 1c respectively) and their cobalt carbonyl complexes are reported. In the absence of alkynes the PNP ligands chelate to the cobalt rather than bridging the two cobalt centers. Although the PNP ligands are chiral the crystal structures are best solved in centrosymmetric space groups with disorder at the chiral carbon with the exception of (PNP3)Co2(CO)6, 2c, which is solved in a non-centrosymmetric space group.
When the PNP ligand chelates to cobalt, as in 2, the compounds show activity for the catalytic Pauson-Khand reaction, whereas when the PNP ligand bridges, as in 3, the reaction precedes stiochiometrically. The use of these chiral ligands has not yet resulted in enantioselective catalytic Pauson-Khand cycloadditions. However, a small 15% e.e. was detected for the stiochiometric Pauson-Khand cycloaddition with 3c as the metal substrate. / Master of Science
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Mångkulturella och homogena skolor : En kvalitativ studie om lärares syn på undervisning om religioner vid fyra sydsvenska skolorJacobson, Petra January 2015 (has links)
The purpose of this paper is to examine if there are any differences or similarities when it comes to teaching religion in a multicultural school versus teaching religion in a homogeneous school in Sweden. How do teachers describe religious education in schools and how do they justify their teaching strategies? What similarities or differences are there between teachers' approaches when teaching religion in homogeneous versus multicultural schools?The study is based on qualitative interviews which includes a total of four schools; two homogeneous and two multicultural. These schools have been selected with the help of the Migration Board's annual report from 2014 as well as from my own personal knowledge. One religious teacher from each of the schools was interviewed.The conclusion, among others, is that ethnic Swedish pupils do not have the same understanding of religion as students of different ethnicity. It also proved that by having students with a different culture to the Swedish talk about their traditions and religion developed a greater understanding among all students. / Syftet med detta examensarbete har varit att undersöka huruvida det är några skillnader eller likheter med att undervisa om religioner på en mångkulturell respektive homogen skola i Sverige. Hur beskriver lärarna undervisningen om religioner i skolan och hur motiverar de sina undervisningsstrategier? Vilka likheter eller skillnader finns mellan lärarnas syn på undervisning om religioner i homogena respektive mångkulturella skolor?Undersökningen baseras på kvalitativa intervjuer där sammanlagt fyra skolor är med i studien, två homogena samt två mångkulturella. Dessa skolor har valts ut med hjälp av Migrationsverkets årsrapport från 2014 samt personlig kännedom. En religionslärare från vardera skola har intervjuats.Slutsatserna blev bland annat att de etniskt svenska eleverna inte hade en förståelse för religion på samma sätt som eleverna med annan etnicitet. Det visade sig också att en större förståelse utvecklades bland alla elever genom att låta elever med annan kultur än den svenska berätta om sina traditioner och religion.
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Synthesis and reactivity studies of mono- and diaurated species bearing N-heterocyclic carbene ligandsGómez Suárez, Adrián January 2014 (has links)
The use of Au-NHC complexes in homogenous gold catalysis has become very popular during the last 10 years. The work described in this thesis represents a modest contribution towards a better understanding of the reactivity of these fascinating complexes and the intermediate species involved during gold-catalysed transformations. There are two main themes that permeate the following chapters: a) synthesis and reactivity studies of monoaurated species and b) synthesis and reactivity studies of diaurated species. The main motivation for the work presented herein was to develop more efficient synthetic routes towards a series of gold complexes, such as [Au(NHC)Cl], [Au(NHC)(OH)] and [{Au(IPr)}₂(μ-OH)][X], in order to be able to further explore their reactivity. Chapter 2 constitutes the first approach that I had with the chemistry of Au-NHC complexes, and describes our efforts to evaluate how the use of a highly sterically demanding NHC ligand affects gold-catalysed transformations. Chapters 3 and 4 explore alternative, more efficient synthetic routes towards known Au- NHC complexes. For example, a new, highly robust protocol has been developed for the synthesis of [Au(NHC)X] (X = Cl, Br, I) complexes, which are the starting materials to prepare a wide range of Au-NHC based species. Moreover, as a result of our investigations it has been possible to isolate a series of [Au(NHC)(OH)] species and to gain some insight into the stability of these complexes. Chapters 5 and 6 describe the synthesis and applications of digold hydroxide species [{Au(IPr)}₂(μ-OH)][X] in a series of catalytic and stoichiometric transformations. For example, they have been used as silver-free catalysts for water-inclusive gold-catalysed transformations or to access key intermediates in gold catalysis, such as gem-diaurated and σ,π-digold-acetylide species. Finally, Chapter 7 combines what we learned about the reactivity of [{Au(IPr)}₂(μ- OH)][X] in order to develop for the first time a gold-catalysed transformation where two gold centres independently react with two substrate molecules to catalyse the hydrophenoxylation of alkynes.
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SPIN EXTENSIONS AND MEASURES ON INFINITE DIMENSIONAL GRASSMANN MANIFOLDS.PICKRELL, DOUGLAS MURRAY. January 1984 (has links)
The representation theory of infinite dimensional groups is in its infancy. This paper is an attempt to apply the orbit method to a particular infinite dimensional group, the spin extension of the restricted unitary group. Our main contribution is in showing that various homogeneous spaces for this group admit measures which can be used to realize the unitary structure for the standard modules.
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Development of Ruthenium Catalysts for Water OxidationLaine, Tanja M. January 2016 (has links)
An increasing global energy demand requires alternative fuel sources. A promising method is artificial photosynthesis. Although, the artificial processes are different from the natural photosynthetic process, the basic principles are the same, i.e. to split water and to convert solar energy into chemical energy. The energy is stored in bonds, which can at a later stage be released upon combustion. The bottleneck in the artificial systems is the water oxidation. The aim of this research has been to develop catalysts for water oxidation that are stable, yet efficient. The molecular catalysts are comprised of organic ligands that ultimately are responsible for the catalyst structure and activity. These ligands are often based on polypyridines or other nitrogen-containing aromatic compounds. This thesis describes the development of molecular ruthenium catalysts and the evaluation of their ability to mediate chemical and photochemical oxidation of water. Previous work from our group has shown that the introduction of negatively charged groups into the ligand frameworks lowers the redox potentials of the metal complexes. This is beneficial as it makes it possible to drive water oxidation with [Ru(bpy)3]3+-type oxidants (bpy = 2,2’-bipyridine), which can be photochemically generated from the corresponding [Ru(bpy)3]2+ complex. Hence, all the designed ligands herein contain negatively charged groups in the coordination site for ruthenium. The first part of this thesis describes the development of two mononuclear ruthenium complexes and the evaluation of these for water oxidation. Both complexes displayed low redox potentials, allowing for water oxidation to be driven either chemically or photochemically using the mild one-electron oxidant [Ru(bpy)3]3+. The second part is a structure–activity relationship study on several analogues of mononuclear ruthenium complexes. The complexes were active for water oxidation and the redox potentials of the analogues displayed a linear relationship with the Hammet σmeta parameter. It was also found that the complexes form high-valent Ru(VI) species, which are responsible for mediating O–O bond formation. The last part of the thesis describes the development of a dinuclear ruthenium complex and the catalytic performance for chemical and photochemical water oxidation. It was found that the complex undergoes O–O bond formation via a bridging peroxide intermediate, i.e. an I2M–type mechanism.
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Investigating nucleation control in batch and flow using non-photochemical laser-induced nucleationMackenzie, Alasdair Morgan January 2017 (has links)
The practical application of non-photochemical laser-induced nucleation (NPLIN) to continuous flow was investigated. Supersaturated aqueous solutions were screened with a 5 ns pulsed laser (532 nm 44 MW cm-2) for NPLIN activity. Upon irradiation succinic acid nucleated at S20 = 4.3 and adipic acid at S20 = 2.0 - 3.0. NPLIN activity is reported for the first time in nicotinic acid (S20 = 2.6 - 3.0). No overall pattern was observed of chemical structure on NPLIN activity. From inorganic compounds similarly screened, ammonium chloride (S20 = 1.04 - 1.20) was identified as most suitable for further tests. It was shown to have an increase of NPLIN crystals with higher supersaturation from 13 at S = 1.038 to 252 at S = 1.135. A quadratic increase in number of crystals with increased laser power. The effects of NPLIN upon ammonium chloride are diminished upon filtration through a 0.2 μm poly (ether sulfone) filter, reducing the number of crystals from 350 to 10 per 70 mJ pulse (25 MW cm-2). The use of NPLIN in continuous flow was demonstrated from the first time. A S23 = 1.1 solution of aqueous ammonium chloride in flow produced crystals when irradiated by 10 pulses s-1 of a 1064 nm 6 ns laser. When the laser was stopped, crystals were no longer produced and the system returned to flowing supersaturated solution. Lab scale apparatus for continuous NPLIN experiments was developed. A design involving a re-dissolution step and loop flow was constructed for both laminar and slug-flow regimes. Nucleation of ammonium chloride (S = 1.1) was demonstrated in both systems. Repeatable NPLIN experiments were hindered by spontaneous nucleation. Spontaneous nucleation in flow was observed around areas where supersaturated solution passed from one component to another. Spontaneous nucleation was also observed upon cooling (25 to 10 °C). Filtration was observed to both suppress NPLIN and spontaneous nucleation in flow.
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Charakterisierung von Intermediaten in Cobalt-vermittelten Reaktionen / Characterization of Intermediates in Cobalt-Mediated ReactionsKreyenschmidt, Friedrich 22 January 2019 (has links)
No description available.
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Ability Grouping in Elementary EducationMcCarter, Anna Kathryn 01 December 2014 (has links)
Ability grouping in education is a common practice used to differentiate instruction in order to meet the academic needs of students. The primary purpose for grouping students by ability is to increase their academic growth and achievement by providing instruction at the students’ current instructional level. However, there is much conflicting research regarding the impact of grouping students by ability and its link to student achievement. The purpose of this study was to determine if there is a statistically significant difference between school-wide student achievement in grades 3, 4, and 5 based on the type of grouping: ability grouped or not grouped by ability classroom settings. Data were collected from the Tennessee Department of Education website for the 2012-2013 academic school year as well as from individual school administrators regarding how students were grouped for instruction: grouped by ability or not grouped by ability. Independent samples t-tests were run to determine if there is a significant difference between students who received instruction in ability grouped setting and those that were not placed in an ability grouped classroom. The results of this study indicated that there is no difference in achievement scores based on the type of instructional setting (ability grouped or not grouped by ability) in reading and math in grades 3, 4, and 5.
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Methods for experimental estimation of anelastic material propertiesDalenbring, Mats January 2001 (has links)
No description available.
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