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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Electric stabilization and destabilization of nitrogen centered radical cations

Steffek, Daniel John. January 1982 (has links)
Thesis (Ph. D..)--University of Wisconsin--Madison, 1982. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 188-209).
2

Reactions of methylnorbornyl cations and reactions of the norticyclyl-3-carbinyl cation

Bergman, Robert G. January 1966 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
3

Cation and water shifts in response to pressor agents in the conscious dog

Warren, James Darcy January 1960 (has links)
The hallmark of essential hypertension is a persistent elevation of blood pressure. Certain changes are associated with the state of hypertension including a derangement of water and electrolytes. Recent work indicates the upset in sodium and water may be causally related to the hypertension. Transitary, acute hypertension may be produced by means of drugs. The drug induced blood pressure rise is accompanied by a disturbance in water and electrolytes. Further work is required to clarify the relationship between shifts in electrolytes and agents that may increase blood pressure (pressor agents). In order to carry out the programme of research on pressor agents it was necessary to review the fundamental tool, namely the accurate measurement of shifts in water. This review led to a refinement in the technique of measuring water by infusing inulin continuously. With nephrectomized animals the inulin dilution technique is a satisfactory method to measure the extracellular space. An equally accurate index of the extracellular space can be provided with an inulin infusion which maintains the extracellular inulin concentration at a constant level. In the present study the cation and water shifts between cells and the extracellular space associated with two dissimilar pressor agents were observed, using trained, conscious dogs. The pressor agents used were norepinephrine, elaborated by the adrenal medulla and pitressin, elaborated by the posterior pituitary gland. Norepinephrine had no effect, in our hands, on sodium, potassium or water movement. Pitressin had distinct effects, with rapid depression of the extracellular volume and the extracellular sodium concentration, and elevation of the extracellular potassium concentration. The changes caused by pitressin were associated with a pressor response. / Medicine, Faculty of / Graduate
4

Studies on cation exchange capacity of plant roots with reference to their ecological phenomena.

Epstein, Eliot 01 January 1953 (has links) (PDF)
No description available.
5

Developing collaborative XML editing systems

Gerlicher, Ansgar Robert Sandy January 2007 (has links)
In many areas the eXtensible Mark-up Language (XML) is becoming the standard exchange and data format. More and more applications not only support XML as an exchange format but also use it as their data model or default file format for graphic, text and database (such as spreadsheet) applications. Computer Supported Cooperative Work is an interdisciplinary field of research dealing with group work, cooperation and their supporting information and communication technologies. One part of it is Real-Time Collaborative Editing, which investigates the design of systems which allow several persons to work simultaneously in real-time on the same document, without the risk of inconsistencies. Existing collaborative editing research applications specialize in one or at best, only a small number of document types; for example graphic, text or spreadsheet documents. This research investigates the development of a software framework which allows collaborative editing of any XML document type in real-time. This presents a more versatile solution to the problems of real-time collaborative editing. This research contributes a new software framework model which will assist software engineers in the development of new collaborative XML editing applications. The devised framework is flexible in the sense that it is easily adaptable to different workflow requirements covering concurrency control, awareness mechanisms and optional locking of document parts. Additionally this thesis contributes a new framework integration strategy that enables enhancements of existing single-user editing applications with real-time collaborative editing features without changing their source code.
6

Silylènes stabilisés par des phosphines : précurseurs de nouveaux cations silyliumylidènes et hétérocycles insaturés / Phosphine-stabilized silylenes : precursors of new silylumylidene cations and unsaturated heterocycles

Nougué, Raphaël 29 January 2018 (has links)
Ce travail de thèse est axé sur la réactivité de silylènes stabilisés par un ligand phosphine et notamment leur usage en tant que précurseurs de cations silyliumylidènes (R-Si:+), qui sont des espèces cationiques du silicium avec seulement un substituent et 4 électrons de valences. La stabilisation des silyliumylidènes, espèces hautement réactives, sera envisagée via la coordination des deux bases de Lewis au niveau des deux orbitales vacantes du centre silicié cationique. Le premier chapitre constitue un état de l'art des études portant sur la stabilisation et la réactivité des silylènes. Une emphase particulière a été apportée à la description de leurs propriétés électroniques qui sont responsables de la balance stabilité-réactivité de ces espèces. Le deuxième chapitre présente la réactivité des complexes de silylènes stabilisés par un ligand phosphine dans l'activation réversible des liaisons- E-H (E = R3Si, R2P) via des additions oxydantes/éliminations réductrices. Ce type de réaction est relativement rare pour les complexes non-métalliques mais fréquent avec les complexes de métaux de transition. Le dernier chapitre traite de la synthèse et de la caractérisation d'espèces divalentes cationiques Si(II), les cations silyliumylidènes stabilisés par coordination de deux de ligands L différents comme les phosphines, les sulfures, les pyridines et les carbènes N-hétérocycliques NHC. Parmi les espèces préparées, le cation silyliumylidène stabilisé par une phosphine, de façon intramoléculaire, et le diméthylsulfure, base de Lewis labile, se distingue par une très grande réactivité vis-à-vis de réactifs variées (oléfines, alcynes, silanes,...) conduisant à des cations silylium stabilisés, intramoléculairement, par un ligand phosphine. Ces derniers, restant très réactifs, sont capables de réagir avec un autre substrat. Ces résultats montrent clairement que les silyliumylidènes sont capables d'activer successivement deux molécules différentes, ce qui devrait permettre d'envisager leur utilisation comme des catalyseurs similaires aux complexes de métaux de transition. / This thesis focuses on the reactivity of phosphine stabilized silylenes, and particularly their use as precursors of low-coordinate four-valence-electrons silyliumylidene ions (R-Si:+). The stabilization of those highly reactive species will be considered via the coordination of two Lewis bases at the cationic silicon center featuring formally two empty orbitals. In the first chapter an overview concerning the stabilization and reactivity of silylenes is presented. Particular emphasis has been placed on the description of their electronic properties which are responsible for the stability-reactivity balance of these derivatives. The second chapter concerns the use of phosphine-stabilized silylene complexes for the reversible activation of E-H bonds (E = R3Si, R2P) via oxidative addition/reductive elimination processes, which are classical in organometallic chemistry, but rarely observed for main group element species. The last chapter deals with the synthesis and characterization of silyliumylidene ions (R-Si:+), and particularly we have considered their stabilization using a set of two different L ligands such as phosphines, sulfides, pyridines and N-heterocyclic carbenes NHC. Of special interest, the phosphine/dimethylsulfide-stabilized silyliumylidene cation, thanks to the labile sulfide ligand, presents a very high reactivity with various reagents (olefins, alkynes, silanes,...), leading to the formation of the corresponding silylium cations, intramolecularly-stabilized by a phosphine ligand. These latter, remaining very reactive, are able to activate a second type of substrate. These results clearly show that the sililymilydenes are capable of activating successively two different molecules, which should make it possible to envisage their use as catalysts similarly to transition metal complexes.
7

Generation and characterization of cationic and anionic radical peptides

Lam, Ngor-wai. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
8

The rational design and synthesis of ionophores and fluoroionophores for the selective detection of monovalent cations

Benco, John S. January 2003 (has links)
Thesis (Pd. D.)--Worcester Polytechnic Institute. / Keywords: ionophore; fluoroionophore. Includes bibliographical references (p. 154-162).
9

Cation exchange mechanisms in soil mineral and organic colloids

DeMumbrum, Lawrence E., January 1955 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 58-65).
10

Interaction of cations with poliovirus

Mapoles, John Eric. January 1980 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 134-140).

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