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Élément chimique

vignette| redresse=1.6| Échantillons des corps simples, classés selon le tableau périodique. Ceux qui manquent dans le tableau sont trop radioactifs pour être présentés en toute sécurité. Un élément chimique est la classe des atomes dont le noyau compte un même nombre de protons. Ce nombre, noté Z, est le numéro atomique de l'élément, qui détermine la configuration électronique des atomes correspondants, et donc leurs propriétés physicochimiques. Ces atomes peuvent en revanche compter un nombre variable de neutrons dans leur noyau, ce qu'on appelle des isotopes. L'hydrogène, le carbone, l'azote, l'oxygène, le fer, le cuivre, l'argent, l'or, sont des éléments chimiques, dont le numéro atomique est respectivement 1, 6, 7, 8, 26, 29, 47, 79 Chacun est conventionnellement désigné par un symbole chimique : H, C, N, O, Fe, Cu, Ag, Au Au total, 118 éléments chimiques ont été observés à ce jour, de numéro atomique 1 à 118. Parmi eux, ont été identifiés sur Terre dans le milieu naturel, et 80

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Conception acoustique de systèmes microtechniques

Jean-Daniel Lüthi

Considered as one of the most difficult complications in horology, the mechanical chiming watch, known as the striking watch, has today become one of the symbols of high craftsmanship. When it chimes the hour the sound of a striking watch must not only be harmonious to the ear of the hearer but also be identical from one watch to another. Today only a few talented watchmakers produce these watches. The resulting empiricism sometimes translates into significant differences between the sounds of these watches. One particularly complex aspect in the application of sound to a striking watch is the appreciation of the sound quality as well as the adequacy to the sound reference. This thesis aims to identify the principal influencing factors at the origin of the variances in sound from one striking watch to another and to identify those that allow the sound of one watch to conform to a recognised ideal sound. The problem is approached from two different angles. The first angle of physical reality, attempts to describe and characterise the sound produced by a watch according to physical parameters. The second angle of perceptive reality models our perception of sound. A virtual spectrum can be established by taking into account psychoacoustic aspects. This is derived from the real spectrum and allows not only a quantified measure of the perceived pitch but also an appreciation of the tone quality. The experimental work relies on the implementation of designed experiments using a functional sample. This reproduces the striking system at the same time allowing the modification of parameters necessary for the planned experiments. The physical spectrum combined with the virtual spectrum allows the identification of the principal influencing factors. Amongst these are hammer-gong pre-penetration, the contact geometry as well as the position of the hitting point and the contact time. By means of the generalised mass, it is possible to modify the perceived pitch within a significant range of frequencies which makes this factor an important element in the adequacy to the recognised ideal of sound. Finally, this work illustrates the importance that should be accorded to the implementation of measuring tools and appropriate characterisation of sound if the processes in the mechanical striking watch industry are to be mastered. Also included is a description of the factors that the watchmaker must control to ensure minimal variation from one watch to another in a production series.

EPFL2011

Chargement

Metal based anti-cancer drugs (metallodrugs) such as cisplatin are a cornerstone of cancer chemotherapy. However, development of this class of compound has been hindered by our lack of understanding of how they function. This is mainly because existing method to study the mechanism of action of metallodrugs are lacking as they were either directly adapted from methods to study organic drugs which have very different chemical properties or current limits in technology and knowledge were a bottleneck to the development of suitable methods. Mass spectrometry (MS) has emerged as a powerful tool which can be applied to study the mechanism of action of metallodrugs. Many different MS methods exist which can be adapted to study different aspects of drug action while accounting for the unique chemical nature of metallodrugs. In this dissertation, we develop MS strategies to study how platinum and ruthenium metallodrugs work and study a few important aspects of their function. Firstly, the in vitro distribution of and ligand state of metallodrugs were studied by imaging mass spectrometry. Next, we attempted to find novel protein targets of metallodrugs using a novel protein expression profiling approach. Promising metallodrug protein targets obtained from this study were then validated via biochemical methods. To facilitate the application of MS based protein-metallodrug fragmentation experiments for finding binding sites of metallodrugs on proteins, we developed and optimized web-based tools for automatic processing of complex spectra from these experiment. We then applied these tools to study the interaction of metallodrugs on relevant proteins, which provided insight into the specific binding properties of metallodrugs on proteins.

EPFL2016

Chargement

Design of novel radiating elements for SATCOM phased arrays in Ku-Band

Baptiste Fernand Hornecker

The present thesis deals with the design of a planar antenna array for the communication between a civil aircraft (Dassault's Falcon) and an Inmarsat satellite. The final goal is to provide high speed Internet access in X/Ku-Band (8-12GHz / 12-18GHz), and possibly even in K/Ka- Band (18-27GHz / 17-40GHz). The study starts with the Ku-Band only, then evolves towards the transmission band and finishes with their Ka-Band counterparts. The main constraint of the thesis is that the final result should be a low profile antenna that will be easy to integrate below the fuselage of an aircraft. At the same time, the antenna has to provide a beam steering mechanism in order to track the position of the targetted satellite while the aircraft is moving. The usual way to achieve it is to implement some dedicated electronic chips below each radiating element of array. Dassault Aviation has its own alternate and more mechanical oriented solutions. Since the communication system is intended for top-notch business jets produced in small series, cost is not here a decisive criterion. This thesis assumes the existence of the beam-steering system and concentrates on a proof of concept and careful design of the antenna elements that will constitute the final array. They have to satisfy tight constraints in terms of size, return loss, mutual coupling with neighbors, efficiency, radiation pattern and dual circular polarization quality. Printed multilayer antennas have been retained as the best candidates, and themain parts of the thesis have been dedicated to their study. The thesis concludes with the presentation of an apparently completely unrelated and independant topic, namely the simulation of nanoscale 2D planar structures based on Graphene. The rationale for this last chapter is to provide a prospective study of the use of Graphene to create a variable capacitance. This component is always needed in the beamforming network of reconfigurable and scanning arrays. Our laboratory is developing a deep knowledge of the electromagnetic properties of Graphene-based devices and these varicaps could lead to very interesting applications in high frequencies, once the Graphene technology has definitely progressed. Thanks to electrostatics Green's functions, a variable capacitor based on Graphene has been simulated, and a Quantumeffect -the Quantum capacitance of Graphene- has been successfully tackled from a numerical point of view.

EPFL2016

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Tableau périodique des éléments

vignette|400px|Tableau périodique des éléments au . 400px|vignette|Avec davantage de détails par élément. Le tableau périodique des éléments, également appelé tableau ou table de Mendeleïev, classific

Uranium

L’uranium est l'élément chimique de numéro atomique 92, de symbole U. Il fait partie de la famille des actinides. L'uranium est le naturel le plus abondant dans la croûte terrestre, son abondance

Isotope

thumb|upright=1.2|Quelques isotopes de l'oxygène, de l'azote et du carbone. On appelle isotopes (d'un certain élément chimique) les nucléides partageant le même nombre de protons (caractéristique de

CH-410: Physical and chemical analyses of materials

The course relates on the use of electromagnetic (X-Ray) and corpuscular (electrons) radiations for physical and chemical analysis of solid materials.

CIVIL-449: Nonlinear analysis of structures

This course deals with the nonlinear modelling and analysis of structures when subjected to monotonic, cyclic, and dynamic loadings, focusing in particular on the seismic response of structures. It introduces solution methods for nonlinear static and dynamic problems.

MSE-101(a): Materials:from chemistry to properties

Ce cours permet l'acquisition des notions essentielles relatives à la structure de la matière, aux équilibres et à la réactivité chimique en liaison avec les propriétés mécaniques, thermiques, électriques et magnétiques des matériaux.