• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 184
  • 83
  • 20
  • 14
  • 12
  • 9
  • 8
  • 8
  • 8
  • 7
  • 3
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 404
  • 66
  • 44
  • 36
  • 36
  • 33
  • 32
  • 31
  • 31
  • 29
  • 29
  • 28
  • 25
  • 24
  • 24
  • 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.
41

Modeling planar 3-valence meshes

Gonen, Ozgur 10 October 2008 (has links)
In architectural and sculptural practice, the eventual goal is constructing the shapes that have been designed. Due to fabrication considerations, shapes with planar faces are in demand for these practices. In this thesis, a novel computational modeling approach to design constructible shapes is introduced. This method guarantees that the resulting shapes are planar meshes with 3-valence vertices, which can always be physically constructed using planar or developable materials such as glass, sheet metal or plywood. The method introduced is inspired by the traditional sculpture and is based on the idea of carving a mesh by using slicing planes. The process of determining the slicing planes can either be interactive or automated. A framework is developed which allows user to sculpt shapes by using the in- teractive and automated processes. The framework allows user to cut a source mesh based on its edges, faces or vertices. The user can sculpt various kinds of developable surfaces by cutting the parallel edges of the mesh. The user can also introduce in- teresting conical patterns by cutting dierent vertex, edge, face combinations of the mesh.
42

The Application of Molecular Wire-Like Ruthenium Complexes Containing Polyferrocenyl-Ethynyl as a spacer

Lin, Shu-fan 04 February 2008 (has links)
The preparations of multinuclear supramolecules assembled from ethynylferrocene(s) redox-active subunit end-capping with [(£b5-C5H5)(dppe)Ru] metal centers are described. Electrochemical measurements indicate that ferrocenyl-ethynyl spacers appear to be promising spacers which can ensure fast and quantitative transfer of information between two Ru2+ metal centers.
43

Tetrathiafulvalene Schiff-base ligands and anion receptors

Bejger, Christopher Michael 12 November 2013 (has links)
Over the last decade, the classic organic donor tetrathiafulvalene (TTF) has emerged as an important functionality in supramolecular systems and complex ligand chemistry. Due to synthetic advances, TTF is no longer a moiety strictly limited to the area of charge transfer salts in material science. In fact, many complex systems incorporating the electron rich donor system are known. More can be imagined. This doctoral dissertation describes the author's journey in designing, synthesizing, and studying various compounds in which the TTF moiety serves a practical purpose, oftentimes giving known molecules new functions. The reported findings have led to a greater understanding of anion binding effects on TTF-containing anion receptors, the use of transition metals to pre-organize [pi]-faces for through-space donor-acceptor interactions, and the introduction of actinide species to tetrathiafulvalene ligands. The first Chapter provides a brief introduction and a short history of TTF chemistry. It also provides an overview describing the fundamental properties of TTF compounds, including TTF dimeric behavior and redox properties. Chapter 2, as the major focus of this dissertation, details the use of a flexible TTF-modified macrocyclic ligand, which upon metallation can effectively preorganize two TTF units to interact when oxidized. Specifically, a new way to stabilize the through-space mixed-valence TTF dimer, in which a transition metal can affect the degree of interaction between the two TTF units, is described. The mixed-valence TTF species in question could see use as components in molecular machines and could play an important role as molecular organic conductors, and discussions along these lines are included in this chapter. These mixed valence complexes were investigated by spectroscopic (¹H-NMR, UV-Vis NIR titrations, and EPR analysis) and X-ray single crystallographic analyses involving both the neutral and oxidized products. Chapter 3 introduces the synthesis, characterization, and electrochemistry of the first TTF-ligand to form a complex with an actinide cation. Chapter 4 details the synthesis, binding studies and X-ray single crystallographic analyses of a TTF-based electrochemical sensor for dihydrogen phosphate anion detection. Experimental procedures and characterization data are reported in Chapter 5. / text
44

Studies of extended cyanines and related mixed valence compounds

Zhao, Xiaodong 05 1900 (has links)
No description available.
45

A study of passivity and stress corrosion cracking (SCC) of alloy 800 in simulated steam generator crevice solution containing thiosulfate and sulphide species

Kulandaivel, Santhoshkumar Unknown Date
No description available.
46

Towards a Wireless EEG System for Ambulatory Mental Health Applications

Jackson, Gregory 28 November 2013 (has links)
The purpose of this thesis was to create and test a proof-of-concept novel ambulatory EEG system to monitor emotional valence in real-time. A qualitative comparison of a wireless EEG acquisition system by the imec group to a gold standard laboratory EEG system was successfully performed. A new wireless transmission system was created using the Texas Instruments’ ADS1299 EEG front-end chip and quantitatively compared to the gold standard system. This system and the ADS1299 performance demonstration kit were used to evaluate several equations for emotional valence classification. Three of these equations were able to correctly classify emotional valence on a positive-neutral vs. negative basis over 90% of the time on the performance demonstration kit and over 90% of the time on the wireless system. The wireless data was acquired and saved on a novel BlackBerry application that also allowed emotional self-assessment by the user during testing.
47

Towards a Wireless EEG System for Ambulatory Mental Health Applications

Jackson, Gregory 28 November 2013 (has links)
The purpose of this thesis was to create and test a proof-of-concept novel ambulatory EEG system to monitor emotional valence in real-time. A qualitative comparison of a wireless EEG acquisition system by the imec group to a gold standard laboratory EEG system was successfully performed. A new wireless transmission system was created using the Texas Instruments’ ADS1299 EEG front-end chip and quantitatively compared to the gold standard system. This system and the ADS1299 performance demonstration kit were used to evaluate several equations for emotional valence classification. Three of these equations were able to correctly classify emotional valence on a positive-neutral vs. negative basis over 90% of the time on the performance demonstration kit and over 90% of the time on the wireless system. The wireless data was acquired and saved on a novel BlackBerry application that also allowed emotional self-assessment by the user during testing.
48

Equivalents, atomes, molecules ...

Grimaux, Édouard, January 1866 (has links)
Thèse-Paris. / At head of title: Faculté de médecine de Paris. Concours pour l'agrégation (section de chimie.). Bibliography: p. [107]-108.
49

Dipole moment, molecular shape and valence angle ...

Walls, William Sparks, January 1932 (has links)
Thesis (Ph. D.)--Princeton University, 1932.
50

Electromers of 2-pentene ...

Foreman, Melvin Orvil, January 1933 (has links)
Thesis (Ph. D.)--University of Chicago, 1929. / Lithoprinted.

Page generated in 0.0336 seconds