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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.
1

Study of Vibration Assisted Nano Impact-Machining by Loose Abrasives (VANILA)

James, Sagil 02 June 2015 (has links)
No description available.
2

A PRECISION INSTRUMENT FOR RESEARCH INTO NANOLITHOGRAPHIC TECHNIQUES USING FIELD-EMITTED ELECTRON BEAMS

Hii, King-Fu 01 January 2008 (has links)
Nanomanufacturing is an active research area in academia and industry due to the ever-growing demands for precision surface modifications of thin films or substrates with nanoscale features. Conventional lithographic techniques face many challenges as they approach their fundamental limits. Consequently, new nanomanufacturing tools, fabrication techniques, and precision instruments are being explored and developed to meet these challenges. It has been hypothesized that direct-write nanolithography might be achieved by using a field-emitted electron beam for nanomachining. This dissertation moves this research one step closer by developing a precision instrument that can enable the integration of direct-write nanolithography by a field-emitted electron beam with dimensional metrology by scanning tunneling microscopy. First, field emission from two prospective electron sources, a carbon nanotube field emitter and a sharp tungsten field emitter, is characterized at distances ranging from sub-micrometer to a few micrometers. Also, the design and construction of a low thermal drift piezoelectric linear motor is described for tip-sample approach. Experiments indicate that: the step size is highly repeatable with a standard deviation of less than 1.2 nm and the thermal stability is better than 40 nm/◦C. Finally, the design and construction of the instrument are presented. Experiments indicate that: the instrument is operating properly in scanning tunneling microscope mode with a resolution of less than 2 Å.
3

Ablation laser femtoseconde pour le contrôle de la micro et nano structuration / Femtosecond laser ablation for controlling micro and nano structruration

Bruneel, David 22 December 2010 (has links)
Le développement actuel de la technologie induit une constante nécessité d’obtenir des tailles de plus en plus petites pouvant descendre jusqu’à des dimensions micrométriques et sub -micrométriques. L’ablation laser, qui a le grand avantage d’un enlèvement de matière très précis, est un candidat prometteur. Dans cette thèse on démontre la faisabilité de tirer avantage des impulsions laser femtosecondes avec la matière pour la micro et nano structuration, et ceci en ayant développé une machine compacte de grande précision et flexibilité. Une approche théorique comparant les régimes d’interaction à haute et basse cadence est présentée. Des investigations de l’efficacité du temps de procédé aussi bien que l’effet de la cadence pendant l’ablation de métaux ont été effectuées. Le potentiel de l’outil multifonctionnel couplé avec un oscillateur laser femtoseconde à haute cadence est montré pour différentes applications en biotechnologie. Les résultats sur la cartographie d’une large zone aussi bien que la nano découpe de précision de tissus biologiques et de matériaux variés sont présentés. Cet outil polyvalent couvre de larges domaines de recherche de la nano découpe d’échantillons biologiques aussi bien que la nanostructuration de différents types de matériaux. C’est d’un grand intérêt pour de nombreuses applications en science des matériaux, nanobiotechnologie et nanomédecine / The current development of technology makes constant the necessity of getting smaller and smaller features sizes down to micrometer and sub micrometer scales. Laser ablation, which has the great advantage of precise material removal, is a promising candidate. In this dissertation we have demonstrated the feasibility to take advantage of the interaction of femtosecond laser pulses with matter for micro- and nano-structuration and this by having developed a compact and high accurate and flexible apparatus. An analyse of the specific physical mechanisms of laser-matter interaction in the femtosecond regime is presented. Investigations on processing time efficiency as well as the effect of the repetition rate during ablation of metals have been performed. The potential of the multifunctional tool coupled with a compact high repetition rate femtosecond oscillator is shown for different applications in biotechnology. Results on large area mapping as well as accurate nanoprocessing of biological tissue and various materials are presented. This versatile tool covers wide research fields from the nanoprocessing of biological samples as well as the nanostructuring of different type of materials. It is of great interest for many applications in material science, nanobiotechnology and nanomedicine

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