This dissertation aims to advance the current state of use of silicon atomic force microscope (AFM) cantilevers with integrated heaters. To this end, the research consists of two primary thrusts - demonstrating new applications for the cantilevers, and advancing the current state of understanding of their thermal and mechanical behavior to enable further applications. Among new applications, two are described. In the first application, the cantilevers are used for nanoscale material deposition, using heat to modulate the delivery of material from the nanoscale tip. In the second application, the cantilever performs thermal analysis with nanoscale spatial resolution, enabling thermal characterization of near surface and composite interphase regions that cannot be measured with bulk analysis techniques. The second thrust of the research seeks to address fundamental questions concerning the precision use of heated cantilevers. Efforts to this end include characterizing the mechanical, electrical, and thermal behavior of the cantilevers, and optimizing calibration methodology. A technique is developed for calibrating the cantilever spring constant while operating at elevated temperature. Finally, an analytical model is developed for the heat flow in the cantilever tip and relevant dimensionless numbers that govern the relative importance of the various components of the thermal environment are identified. The dimensionless numbers permit exploration of the sensitivity of the tip-substrate interface temperature to the environmental conditions.

Optical imaging techniques have improved much over the last fifty years since the invention of the laser. With a high brightness source many imaging applications which were once inaccessible to researchers have now become a reality. Among these techniques, the most beneficial one is the use of lasers for both wide-field and confocal imaging systems. The aim of this study was to design a laser imaging system based on the concept of laser scanning confocal microscopy. Specifically the optical system was based on optical fibers allowing the user to image remote areas such as the inner surface of rifled gun barrels and/or pipes with a high degree of precision (+/- 0.01 mm). In order to build such a system, initially the theoretical foundation for a confocal as well as a wide-field imaging system was analyzed. Using this basis a free-space optical confocal system was built and analyzed. The measurements support the fact that both the objective numerical aperture and pinhole size play an important role in the radial and axial resolution of the system as well as the quality of the images obtained. To begin construction of a confocal, optical-fiber based imaging system first an all fiber wide-field imaging system was designed and tested at a working wavelength of 1550 nm. Then an all fiber confocal system was designed at a working wavelength of 808 nm. In both cases results showed that while lateral resolution was adequate, axial resolution suffered since it was found that the design of the optical system needs to take into account under-filling of the objective lens, a result common with the use of laser beams whose divergence is not at all like that of a point source. The work done here will aid technology that will be used in the elimination process of faulty rifling fabrication in defense industry. The reason why the confocal technique is preferred to the conventional wide-field one is the need for better resolution in all directions. Theoretical concepts and mathematical background are discussed as well as the experimental results and the practical advantages of such a system.

A series of pottery samples provided from the survey investigations and excavations from Degirmentepe Mound (Malatya), belonging to Chalcolithic (Ubaid), Early Bronze and Iron Ages, were investigated by petrographic and X-ray diffraction (XRD) analyses to determine their textures, mineralogical compositions and microstructures. The sample microstructures and chemical (semiquantitative) compositions were also studied by scanning electron microscope with energy dispersive X-ray spectrometry (SEM - EDX). The chemical analyses of some samples were further investigated by inductively coupled plasma &ndash / optical emission spectrometry (ICP-OES). Almost all samples were observed to consist of rock fragments, originating from metamorphic and igneous rocks, although larger grain sizes and higher grain to matrix ratios are recorded for Chalcolithic Age samples compared to those samples belonging to Iron Age. XRD investigations on representative samples of the three periods, revealed high abundances of quartz, feldspar, and pyroxene group minerals in all samples, while the presence of hematite and mica minerals were observed both in Chalcolithic and Iron Age samples, but underlying the use of micaceous raw materials mostly in Iron Age. In the XRD traces of the investigated sherds of Chalcolithic and Iron Ages, the absence of clay fractions both in the bulk and oriented samples, supports a minimum firing temperature of around 800- 850 &deg / C, while the presence of mullite phase both in XRD and SEM &ndash / EDX results showed the possible use of high firing temperatures, in the range of 950&ndash / 1050&deg / C, starting from Chalcolithic Age. Chemical compositions of major oxides obtained ICP &ndash / OES analyses exhibit similar compositions both for Chalcolithic and Iron Age samples. Few exceptions observed may indicate possible use of different raw material and/or different manufacturing technique.

This dissertation focuses on quantitative subsurface and mechanical properties imaging potential of AFM probes. Extensive modeling of AFM probes are presented for thorough understanding of capabilities and limitations of current techniques, these models are verified by various experiments, and different methods are developed by utilizing force-sensing integrated read-out active tip (FIRAT), which is an active AFM probe with broad bandwidth. For quantitative subsurface imaging, a 3-D FEA model of AFM tip-sample contact is developed and this model can simulate AFM tip scan on nanoscale-sized buried structures. FIRAT probe, which is active and broadband, is utilized for interaction forces imaging during intermittent contact mode and mechanical characterization capability of this probe is investigated. It is shown that probe dynamics, stiffness, stiffness ambiguity, assumed contact mechanics, and noise are important parameters for the accuracy of mechanical properties imaging. An active tip control mechanism is introduced to limit contact forces during intermittent contact mode. In addition to these, a combined ultrasonic AFM and interaction forces imaging method is developed and modeled to solve the reduced elasticity measurement sensitivity on composite materials. This method is capable of imaging a broader range of elasticity on combination samples such as metal nanoparticles in polymers at nanoscale.

Relatively little is known about the folding and stability of membrane proteins. Conventional thermal or chemical unfolding techniques probe the average behavior of large numbers of molecules and thus cannot resolve co-existing minor and major unfolding pathways and intermediates. Here, I applied single-molecule force measurements based on an atomic force microscope (AFM) to characterize the stability of the membrane protein bacteriorhodopsin (BR). In these mechanical unfolding experiments, an external pulling force played the role of the denaturant and lead to unfolding of the three-dimensional structure of individual proteins. It was found that single BRs unfold step-wise in a well-defined sequence of stable intermediates and in different unfolding pathways. Although single [alpha]-helices were sufficiently stable to unfold in individual steps they also exhibited certain probabilities to unfold in pairs. These observations support the "two-stage" and the "helical-hairpin" model of membrane protein folding. Dynamic force measurements showed that [alpha]-helices and helical hairpins are relatively rigid structures, which are stabilized by narrow energy barriers and have stabilities between 100-10?000 seconds. These forced unfolding experiments were complemented with the development of new force measurement techniques. It is demonstrated that hydrodynamic effects need to be considered to obtain more complete kinetic pictures of single molecules. In addition, two force spectroscopy approaches to measure the complex visco-elastic response of single molecules are presented and applied to BR. These experiments revealed that the unfolding patterns of single proteins are dominated by purely elastic polypeptide extension and determined the dissipative interactions associated with the unfolding of single [alpha]-helices. In addition, it was found that kinks result in a reduced unfolding cooperativity of [alpha]-helices.

<p>The main objective for the work described in this PhD thesiswas to formulate a friction model to characterize thefrictional behavior of paper. More specifically, the modelshould explain a phenomenon that is typical for paper grades,viz.: that the level of paper-to-paper friction is dependent onthe direction and the number of previous slides. The modelshould also explain the lubricating effect oflow-molecular-mass lipophilic compounds (LLC) that occur inpaper on paper-to-paper friction. Furthermore, the model shoulddescribe the types of forces that influence paper-to-paperfiction and explain the mechanism by which the LLC decreasepaper-to-paper friction.</p><p>This thesis consists of a literature review of the basicconcepts of tribology and a summary of the main results andconclusions from four studies on the frictional characteristicsof paper and a study on the friction and adhesion of cellulosesurfaces together with some unpublished material.</p><p>The purpose of the investigation described in the firstpaper was to explain a phenomenon that is typical for papergrades, viz.: the level of paper-to-paper friction is dependenton the direction and the number of previous slides. Thisbehavior is called“friction hysteresis”by theauthors, and it has its origin in the reorientation of thefibers on the surface of a paper and their alignment relativeto the sliding direction.</p><p>The second paper describes a study that was aimed atidentifying lubricants that occur natively in paper. Filterpapers were impregnated with model compounds representing woodextractives, i.e. low-molecular-weight lipophilic compounds,which are present in wood, pulp and paper, and thepaper-to-paper friction was determined. The results of thatstudy show that a wood extractive must fulfill severalstructural criteria in order to lubricate a paper surface: Itmust have a hydrophilic group that can attach to the papersurface and a linear hydrocarbon backbone of sufficientlength.</p><p>Although it is not specifically stated in the second paper,the authors proposed a type of lubrication by which woodextractives decrease paper-to-paper friction that is, ineffect, boundary lubrication. The purpose of the investigationdescribed in the third paper was to clarify whether woodextractives and other low-molecular-mass lipophilic compoundsthat occur in paper can act as boundary lubricants on papersurfaces. The main objective of that study was to investigatethe role of chemical structure of LLC for their orientationrelative to the paper surface, which is an important criterionfor boundary lubrication. Filter papers were impregnated withmagnesium salts of different lipophilic acids, which were usedfor model compounds for the LLC. The deposited layers ofmagnesium salts were characterized by X-ray photoelectronspectroscopy (XPS) and contact angle goniometry and thefriction of the impregnated paper sheets was determined. Theresults show that the degree of lubrication and the resistanceto wear of the layers of a magnesium salt increased withincreasing chain length and increasing degree of linearity ofthe lipophilic acid. Based on the results of that study and ofearlier studies, it is concluded that boundary lubrication isthe type of lubrication by which low-molecular-mass lipophiliccompounds that occur natively in paper decreasepaper-to-paper-friction.</p><p>In boundary lubrication, surfaces are covered withmonolayers of lubricant molecules that comprise an active headgroup that can attach to the surface, e.g. a carboxyl group,and an inert linear backbone, such as a long saturatedhydrocarbon chain. Such compounds form ordered monolayers onsurfaces, so that the backbone points vertically out of planeof the surface. The friction is then determined by theinteractions between the monolayers, which are weaker than theinteractions between the clean surfaces and this gives a lowerfriction.</p><p>The fourth paper describes a study on the origin of thedifferences in friction levels between different linerboardsbased on recycled fiber (old corrugated container, OCC). Thesheets were subjected to two extraction stages and analyzedwith respect to surface roughness and their content oflow-molecular-mass lipophilic compounds (LLC). The resultsshowed that a high amount of LLC in the sheets lead to lowfriction, due to lubrication.</p><p>The fifth paper describes a study that was aimed atdetermining the types of forces that influence the frictionbetween the surfaces of hydrophilic polymers and explaining themechanism by which boundary lubricants decrease the friction.The adhesion and the friction of model systems was measuredwith atomic force microscopy (AFM) using regenerated cellulosefilms and functionalised AFM tips and the effect of fatty acidsand humidity was investigated. The friction significantlyincreased with increasing humidity and that there was a strongcorrelation between the ability of a fatty acid to form ahydrophobic surface and its lubricating performance. Measuredadhesion forces at high humidity were well predicted bytheoretical models that took into account the effect of theLaplace pressure acting in a water meniscus formed aroundcontact regions due to capillary condensation. The resultsindicated that the degree of capillary condensation may beeffectively suppressed by increasing the hydrophobicity of thecontacting surfaces, causing adhesion and friction to decrease.These results suggest that friction between paper surfacesunder ambient conditions is greatly influenced by the degree ofcapillary condensation. Furthermore, lubrication by fatty acidsis achieved by the formation of a vertically oriented,hydrophobic monolayer that can withstand the stresses duringsliding and increase the hydrophobicity of the paper surfaceand thereby suppress capillary condensation.</p><p><b>Keywords:</b>Friction, paper-to-paper friction, frictionhysteresis, fibers, orientation, sliding direction, woodextractives, low-molecular-mass lipophilic compounds, boundarylubrication, adhesion, capillary condensation, Laplacepressure, surface forces, JKR theory, gas chromatography-massspectroscopy, X-ray photoelectron spectroscopy, contact angle,atomic force microscopy</p>

La combinaison de microscope photonique et de caméra est largement utilisée dans les applications de micro-assemblage. Cet instrument indispensable comporte cinq propriétés : un faible champ de vision, une faible profondeur de champ, une faible distance de travail, une forte dépendance à l'éclairage et un encombrement important. La conséquence directe de ces propriétés dans un contexte de micro-assemblage est l'utilisation de système de vision distribué composé d'imageurs de caractéristiques différentes et complémentaires qui ont un coût et un encombrement important. C'est pour cela que notre approche consiste a reconstruire certaines vues indispensables au contrôle de la station par des techniques de rendu d'images, limitant ainsi le nombre de vidéo microscopes photoniques réels dans la station. Pour cela, nous proposons d'utiliser deux techniques, la construction d'images mosaïques et le transfert trifocal. Avant toute chose le système de vision doit être calibré, nous présentons les étapes du calibrage stéréoscopique faible pour ce contexte de microscopie photonique ainsi que leurs améliorations par de nouveaux algorithmes. La construction d'images mosaïques est une technique qui permet de reconstruire une image complète d'une scène à partir d'un ensemble d'images représentant chacune une petite partie de cette scène. Après avoir présenté de nouveaux algorithmes en vue d'améliorer la construction de mosaïques nous l'utilisons pour la supervision de station de micromanipulation. Le transfert trifocal est une technique qui permet à partir d'un simple calibrage stéréoscopique faible de reconstruire une vue virtuelle à partir de seulement deux vues réelles sans le besoin d'information 3D explicite. Après un éclaircissement sur la théorie et la proposition de nouveaux algorithmes nous l'utilisons dans une boucle d'asservissement visuel de type look-and-move, pour contrôler le déplacement d'une micropince. La vue de côté virtuelle permettant le contrôle est reconstruite à partir des vues réelles provenant d'un stéréo microscope photonique.

Les tâches de saisie, de manipulation et d'assemblage d'objets de très<br />petites dimensions sont parmi les thèmes majeurs en micro-robotique. La<br />"micromanipulation" s'adresse d'une manière générale à la manipulation d'objets<br />de dimensions globalement comprises entre 1 micromètre et 1 mm et requiert une<br />résolution de positionnement en rapport avec ces dimensions. Le<br />micro-assemblage consiste à réaliser une séquence d'opérations élémentaires<br />conduisant à l'obtention de micro-composants constitués de différentes pièces.<br />La manipulation de chacune de ces pièces nécessite d'utiliser des effecteurs<br />dédiés, adaptés à leurs particularités (géométrie, dimensions, propriétés<br />mécaniques). Différents types d'outils doivent ainsi être utilisés<br />séquentiellement pour réaliser un micro-assemblage.<br /><br />Dans ce but, une station de micromanipulation a été réalisée. Elle est composée<br />d'une micropince montée sur un manipulateur à trois degrés de liberté. Un<br />système permettant de changer automatiquement l'extrémité de la micropince<br />(i.e. les outils) a plus particulièrement été étudié et réalisé. Il permet de<br />fixer alternativement les outils à l'actionneur de la micropince ou à un<br />magasin en utilisant une colle thermique. Celle-ci est liquéfiée par chauffage<br />ou solidifiée par refroidissement.<br /><br /><br />Ce système de changement d'outils apporte une flexibilité notablement accrue à<br />la station de micromanipulation et permet de réaliser des opérations de<br />micro-assemblage dans des espaces restreints comme par exemple la chambre d'un<br />microscope électronique à balayage. Un plan de travail compliant a également<br />été réalisé. Il permet de limiter les efforts en jeu pendant les opérations de<br />micromanipulation et d'améliorer ainsi le taux de réussite des opérations<br />délicates.

Die Anatomie des Holzes stellt eine entscheidende Einflussgröße bei einer Vielzahl holztechnologischer Prozesse dar. Der Beitrag soll mit Hilfe rasterelektronenmikroskopischer Bildtafeln den anatomischen Bau des Holzes der Rot-Buche vermitteln.

Les microscopes en champ proche permettent d'obtenir la topographie d'un échantillon avec une résolution pouvant atteindre la résolution atomique. Ces techniques permettent également d'accéder à certaines propriétés locales de la surface telles que le potentiel, l'élasticité, la densité d'états... Ces spectroscopies locales sont de type 'contraste' et ne permettent pas de dresser la cartographie chimique de la surface sans connaissance a priori des éléments qui la composent. Les spectroscopies de rayons-X sont des méthodes de caractérisation puissantes qui permettent de déterminer la composition et la structure élémentaire de l'échantillon avec une précision inférieure à l'Ångström. La résolution latérale est essentiellement limitée par la taille du faisceau primaire, couramment de plusieurs μm². Deux voies sont possibles pour l'améliorer: - réduire l'étendue du faisceau primaire excitateur; - limiter la collecte du rayonnement émis à une portion du volume excité, tout en approchant le détecteur au maximum pour garder un rapport signal/bruit suffisant. C'est cette deuxième option que nous avons choisi de développer. Pour cela nous avons collecté localement la luminescence visible issue de l'échantillon par la pointe-sonde d'un microscope à force de cisaillement, constituée d'une fibre optique effilée de faible ouverture. Cette technique a été utilisée pour caractériser des échantillons semiconducteurs micro- et nano-structurés afin d'en obtenir simultanément la topographie et la cartographie de luminescence locale. Ces résultats ont été obtenus non seulement sur une ligne synchrotron mais également à l'aide d'une microsource de laboratoire équipée d'une lentille polycapillaire. Afin de pouvoir étendre ce concept à d'autres types de matériaux, la faisabilité de la collecte de la fluorescence X locale a été évaluée avec la microsource. Pour cela la fluorescence X émise par un échantillon de cobalt a été collectée par un capillaire cylindrique équipant un détecteur EDX. L'influence du diamètre du capillaire sur le niveau de signal a été mesurée. Une simulation numérique a été développée afin d'estimer le niveau de signal obtenu en utilisant un capillaire de 1 μm de diamètre et d'optimiser la géométrie du système. En couplant la microscopie en champ proche et l'analyse XRF, à la lumière de ces résultats, il sera possible d'atteindre 100 nm de résolution latérale en environnement synchrotron et moins de 1 μm à l'aide d'une source de laboratoire. Il serait alors possible de sélectionner un objet particulier sur une surface et d'en faire l'analyse élémentaire.