Part I : Comparing derivatization methods for amino acids ��� one and two-step procedures using gas chromatography ��� flame ion detector (GC-FID) Part II: Story of an icon from its execution until its conservation

Disserta����o apresentada na Faculdade de Ci��ncias e Tecnologia da Universidade Nova de Lisboa para obten����o do grau de Mestre em Conserva����o e Restauro

Caracteriza����o de fibras de ion jelly�� obtidas por electrofia����o

Disserta����o apresentada na Faculdade de Ci��ncias e Tecnologia da Universidade Nova de Lisboa para a obten����o do grau de Mestre em Engenharia Biom��dica

Development of electrospun Ion jelly fibers�� for drug delivery

Disserta����o para obten����o do Grau de Mestre em Biotecnologia

Modelling and optimization of the ion exchange membrane bioreactor for removal of anionic pollutants from drinking water streams

Disserta����o para obten����o do Grau de Doutor em Engenharia Qu��mica, especialidade de Engenharia Bioqu��mica

Time-of-flight secondary ion mass spectrometry: new application for urinary stones analysis

Disserta����o para obten����o do Grau de Doutor em Engenharia F��sica

Atomic force microscopy assisted with electron and ion beam microscopy for the direct measurement of biostructures and DNA samples

Dissertation to obtain a Master degree in Biotechnology

Development of ion jelly thin films for electrochemical devices

Disserta����o para obten����o do Grau de Doutor em Qu��mica Sustent��vel

Compact ion-source based on superionic rubidium silver iodide (RbAg4I5) solid electrolyte

Disserta����o para obten����o do Grau de Mestre em Engenharia F��sica

Ion-beam sources based on superionic solid electrolytes

An ion emitter consisting of a sharp silver tip covered in RbAg4I5 solid electrolyte film has been developed and studied. An accelerating potential is applied and Ag+ ions are emitted from the tip���s apex by field evaporation. The emitted ions are collected by a Faraday cup, producing a current on the pico/nanoampere level which is read by an electrometer. The tips were produced mechanically by sandpaper polishing. The sharpest tip produced had a 2:4 m apex radius. Two deposition methods were studied: thermal vacuum and pulsed laser deposition. The best tip produced a peak current value of 96nA at 180oC, and a quasi-stable 4nA emission current at 160oC, both using an extraction potential of 10kV . The emission dependence on time, temperature and accelerating potential has been studied. Deposited films were characterized by X-ray diffraction (XRD), profilometry, optical and Scanning Electron Microscope (SEM) and Secondary Ion Mass Spectroscopy (SIMS) measurements. Several ion emitters were developed, the latter ones were all able to maintain stable high ion emissions for long periods of time. This investigation was a continuation of an ongoing project backed by the European Space Agency, with the objective of making a proof of concept of this kind of ion emitter with potential application on ion thrusters for orbiting satellites. Going forward, it would be interesting to make a finer analysis of the electrolyte���s conductivity at high temperatures, explore Wien Effect-based emission and to further develop a multi-tip ion emitter prototype.