189 research outputs found
Laser beam characterisation for industrial applications
This thesis describes the theory, development and applications of laser beam
characterisation for industrial laser materials processing systems. Descriptions are given
of novel forms of beam diagnostic systems and their integration into highly automated
industrial tools. Work is also presented that has contributed to the new ISO standard on
beam characterisation. Particular emphasis is given to excimer laser applications and UV
micromachining. [Continues.
Scanning evanescent wave lithography for sub-22nm generations
Current assumptions for the limits of immersion optical lithography include NA values at 1.35, largely based on the lack of high-index materials. In this research we have been working with ultra-high NA evanescent wave lithography (EWL) where the NA of the projection system is allowed to exceed the corresponding acceptance angle of one or more materials of the system. This approach is made possible by frustrating the total internal reflection (TIR) evanescent field into propagation. With photoresist as the frustrating media, the allowable gap for adequate exposure latitude is in the sub-100 nm range. Through static imaging, we have demonstrated the ability to resolve 26 nm half-pitch features at 193 nm and 1.85 NA using existing materials. Such imaging could lead to the attainment of 13 nm half-pitch through double patterning. In addition, a scanning EWL imaging system was designed, prototyped with a two-stage gap control imaging head including a DC noise canceling carrying air-bearing, and a AC noise canceling piezoelectric transducer with real-time closed-loop feedback from gap detection. Various design aspects of the system including gap detection, feedback actuation, prism design and fabrication, software integration, and scanning scheme have been carefully considered to ensure sub-100 nm scanning. Experiments performed showed successful gap gauging at sub-100 nm scanning height. Scanning EWL results using a two-beam interference imaging approach achieved pattern resolution comparable to static EWL imaging results. With this scanning EWL approach and the imaging head developed, optical lithography becomes extendable to sub-22 nm generations
Intelligent laser cladding control system design and construction.
Imperial Users onl
Acoustic Communication for Medical Nanorobots
Communication among microscopic robots (nanorobots) can coordinate their
activities for biomedical tasks. The feasibility of in vivo ultrasonic
communication is evaluated for micron-size robots broadcasting into various
types of tissues. Frequencies between 10MHz and 300MHz give the best tradeoff
between efficient acoustic generation and attenuation for communication over
distances of about 100 microns. Based on these results, we find power available
from ambient oxygen and glucose in the bloodstream can readily support
communication rates of about 10,000 bits/second between micron-sized robots. We
discuss techniques, such as directional acoustic beams, that can increase this
rate. The acoustic pressure fields enabling this communication are unlikely to
damage nearby tissue, and short bursts at considerably higher power could be of
therapeutic use.Comment: added discussion of communication channel capacity in section
A Hybrid System for Dental Milling Parameters Optimisation
This study presents a novel hybrid intelligent system which focuses on the optimisation of machine parameters for dental milling purposes based on the following phases. Firstly, an unsupervised neural model extracts the internal structure of a data set describing the model and also the relevant features of the data set which represents the system. Secondly, the dynamic system performance of different variables is specifically modelled using a supervised neural model and identification techniques from relevant features of the data set. This model constitutes the goal function of the production process. Finally, a genetic algorithm is used to optimise the machine parameters from a non parametric fitness function. The reliability of the proposed novel hybrid system is validated with a real industrial use case, based on the optimisation of a high-precision machining centre with five axes for dental milling purposes
Rapid prototyping of micro-optics for brightness restoration of diode lasers
Abstract unavailable please refer to PD
Proceedings of the 25th Project Integration Meeting
Topics addressed include: silicon sheet growth and characterization, silicon material, process development, high-efficiency cells, environmental isolation, engineering sciences, and reliability physics
Modular integration and on-chip sensing approaches for tunable fluid control polymer microdevices
228 p.Doktore tesi honetan mikroemariak kontrolatzeko elementuak diseinatu eta garatuko dira, mikrobalbula eta mikrosentsore bat zehazki. Ondoren, gailu horiek batera integratuko dira likido emari kontrolatzaile bat sortzeko asmotan. Helburu nagusia gailuen fabrikazio arkitektura modular bat frogatzea da, non Lab-on-a-Chip prototipoak garatzeko beharrezko fase guztiak harmonizatuz, Cyclic-Olefin-Polymer termoplastikozko mikrogailu merkeak pausu gutxi batzuetan garatuko diren, hauen kalitate industriala bermatuz. Ildo horretan, mikrogailuak prototipotik produkturako trantsizio azkar, erraz, errentagarri eta arriskurik gabeen bidez lortu daitezkeenetz frogatuko da
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