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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.

The detection and measurement of "small" air ion concentrations

Mahn, Jeffrey A. January 1971 (has links)
Thesis (M.S.)--University of Michigan, 1971.

Ion pair return in substituted benzhydryl and related systems

Briody, Robert George, January 1964 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 123-125.

An absolute ion velocity gauge and determination of nuclear standards

Gasten, Burt R. January 1963 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 69-70).

A numerical simulation of ion confinement in Phaedrus plugs

Horne, Stephen. January 1984 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The rate of reaction between bromoacetate and thiosulphate ions in dodium chloride and sea water media

Dodimead, Allan John January 1954 (has links)
Rate measurements of the thiosulphate-bromoacetate reaction have been made in sodium chloride and sea water media at 15.3°, 25.2° and 32.0°C and in magnesium chloride at 15.3°C, Rates are more simply dependent on the concentration and kind of cations in the media than upon the ionic strength. The rate constants are approximately 6% higher in neutral solutions of sea water than in sodium chloride media and the higher rate constants are attributed to the presence in sea water of the cations, K⁺, Ca⁺⁺ and Mg⁺⁺. The energy of activation is 16,000±100 cal./mole and the entropy of activation is-6.6 e.u. for the reaction done in both media. The convergence of the rate curves in magnesium and sodium chloride media at high concentrations may be explained by the presence of undissociated species. The magnitude of the correction to the observed rate depends upon the concentration of the cations and the formation constant for the undissociated species. This explanation has been used to account for the decrease in rate in sea water that has been made alkaline. / Science, Faculty of / Chemistry, Department of / Graduate

Ion source development

Kinnear, James Kerr January 1949 (has links)
A radio frequency excited positive ion source has been designed and constructed. Hydrogen gas is excited in a discharge tube by a radio frequency oscillator operating at a frequency of 210 mc./sec. The hydrogen is disassociated and ionized. A voltage of the order of a 2 kV is used to accelerate the positive ions through the exit canal in the end of the discharge tube. The positive ions are then accelerated and focused into a bean by two cylindrical electrostatic lenses using voltages of the order of 10 kV and 50 kV. For purposes of analysing a one lens system is used, accelerating the beam to an energy of the order of 15 kV. A magnetic analyser resolves up to mass three ions, focussing them into a Faraday cup. The source delivers a beam containing 45% protons. A total current of 800 microamperes of positive ions has been measured. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The production of doubly charged helium ions and a study of their elastic scattering by carbon /

Bittner, John W. January 1954 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1954. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Heterometallic Interactions of d8-d10 Metal Ions in the Presence of +2 Cations

Palla, Veladri January 2007 (has links) (PDF)
No description available.

Extraction optics for ion beam generation in the ARIEL facility at TRIUMF

Maldonado Millan, Fernando Alejandro 28 September 2016 (has links)
The proposed ion optics extraction geometry from ARIEL has been optimized based on simulations with Comsol. Geometrical parameters such as the acceleration gap and angle of the face of the vacuum chamber were studied in order to improve the beam 4-emittance and beam spot size. For geometries of interest, additional studies have been performed: voltage dependence, mass dependence, and the effect of the ion source misalignment on the beam parameters and how to compensate them. Simulations and experimental measurements were also performed for the current ISAC surface ion source to corroborate the simulation results. / Graduate / famaldo@uvic.ca

Implantação por recuo de antimônio em silício por bombardeamento com íons de argônio e germânio

Erichsen Junior, Rubem January 1986 (has links)
Estudamos o processo de dopagem de silício com antimônio por recuo promovido por bombardeamento iônico. Em nossas experiências o sistema filme fino de antimônio de 60 nm de espessura depositado sobre silício monocristalino de orientação <100> foi bombardeado com Ar+ ou Ge+ com energias entre 40 e 800 KeV e doses entre 1,0X1014 e 1,0X1017 cm². As amostras foram submetidas e recozimento térmico rápido a temperaturas entre 950 e 1150 ºC por tempos entre 20 e 60 s ou a recozimento prolongado em forno a 600 ºC por 1h. Algumas amostras foram submetidas a recozimento em duas etapas: prolongado a 600ºC por 1h seguido de recozimento rápido a 1200ºC por 5s. A análise das amostras foi feita empregando-se retroespalhamento Rutherford (RBS), espectrometria Auger e medidas em dispositivos Van der Pauw. Os principais resultados são: i) O processo que governa a implantação por recuo e a mistura balística induzida por colisões secundárias. ii) A concentração máxima de dopante situa-se na superfície e toda região dopada localiza-se a profundidade inferior a 0,1 um. iii) A largura do perfil de implantação independo da energia do projétil, e é função da dose incidente. Doses crescentes geram perfis mais profundos. iv) O bombardeamento com Ar+ resulta em recristalização inadequado do silício. O bombardeamento com Ge+ viabiliza perfeita recristalização do silício e boa substitucionalidade do dopante. / We investigated the doping process of silicon with antimony by means of the recoil implantation method. I our experiments a film of antimony deposited over <100> single cristal silicon was bombarded with Ar+ or Ge+ with energies between 40 and 800 KeV and doses ranging from 1,30C1014 to 1,0X1017 cm². Single step annealing of the bombarded samples was performed either in a Rapid Thermal Annealing (RTA) system or in a conventional furnace. IN the former case temperatures ranged from 950 to 1150 ºC and annealing times from 20 to 60s. In the latter case samples were annealed at 600ºC for 1 hour. The samples were analyzed by means of the Rutherford Backscattering spectrometry (RBS) technique Auger spectrometry and electrical measurements in Van der Pauw devices. The main results are: i) Recoil implantation ir governed by ballistic mixing process of collision cascades generated by the incident ions. ii) The maximum antimony concentration occours at the surface and decays rapidly with depth. The profile extends up to a maximum depth of 0,1um, even after annealing. iii) Antimony depth profile are independent of the bombarding particle’s energy, but are dependent on the dose. iv) Ar + bombardment yields imperfect recrystallization at the silicon substrate. Ge+ bombardment yields perfect recrystallization and good substitutionality of antimony atoms after annealing.

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