Maestría en Física Aplicada (tesis)
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Publicación Método basado en aprendizaje profundo para la mitigación de artefactos espejo y el Aliasing producido por el submuestreo lateral en el dominio de Fourier en la tomografía de coherencia óptica(Universidad EAFIT, 2025) Pulgarín Suárez, Diego Alexander; Restrepo Gómez, René; Trujillo Anaya, Carlos Alejandro; Cadavid Muñoz, Juan JoséOptical Coherence Tomography (OCT) is an imaging technique that has revolutionized medical diagnosis by providing high-resolution, three-dimensional images of biological tissues non-invasively. Its initial implementation, Time-Domain OCT (TD-OCT), relied on mechanical scanning to acquire each depth profile, which limited its speed and made it susceptible to motion artifacts from the patient, compromising the quality of in-vivo images. To overcome these limitations, Fourier-Domain OCT (FD-OCT) was developed, which captures the entire information of a depth profile simultaneously. This advancement dramatically increased speed and sensitivity but also introduced new challenges. One of the most significant is the mirror artifact, a conjugate copy of the image that appears due to the real nature of the interferometric signal and its subsequent Fourier Transform. Another key problem is aliasing, which arises from the trade-off between acquisition speed and compliance with the Nyquist sampling theorem. In practice, lateral sampling density is reduced to minimize scan time and motion artifacts, but this undersampling causes high spatial frequencies of the tissue to be incorrectly represented as lower frequencies, degrading image fidelity. The primary goal of the research is to address two specific problems: lateral undersampling, which causes aliasing, and the mirror artifact. Solving the former would allow for reduced acquisition time without sacrificing tomogram quality, while eliminating the latter would optimize the use of the image's depth range. Traditionally, solutions for these artifacts have depended on hardware modifications to the OCT system. These approaches, while effective, are costly, increase equipment complexity, and are not easily applicable to existing systems in clinical settings. In response to these limitations, this work proposes an innovative solution based on deep learning that operates exclusively in the digital post-processing stage of the images. The main advantage of this method is that it requires no physical intervention in the optical system, allowing it to be implemented on data acquired with any conventional OCT equipment. To carry out this task, different Generative Adversarial Network (GAN) architectures were explored, with the Pix2Pix model being identified as the most effective for simultaneously correcting both aliasing artifacts from undersampling and the mirror artifact. The effectiveness of this methodology was rigorously validated through qualitative and quantitative analyses. This research not only demonstrates the potential of GANs to solve complex problems in OCT imaging but also lays a solid foundation for their future application in clinical practice. By improving image quality and acquisition efficiency without the need for new hardware, this post-processing approach has the potential to significantly optimize diagnosis, where accuracy and speed are essential.Publicación Evaluación in-vitro del potencial de hipertermia magnética de nanocompósitos de óxidos de hierro(Universidad EAFIT, 2025) Suárez Gómez, Simón Emilio; Velásquez Torres, Álvaro Andrés; Gómez Ramírez, Luis Alejandro; Urquijo Morales, Jeaneth PatriciaPublicación Estudio computacional de la transferencia de calor por radiación en campo cercano(Universidad EAFIT, 2023) Zambrano Corado, Yordani; David Caro, Jorge LeónThe objective of this research is to conduct a computational study of near-field radiative heat transfer (NFRHT), given the significant importance of this phenomenon in various technological applications. To implement new sensors or actuators with better performance than the current ones, it is necessary to model the NFRHT phenomenon and observe its behavior in new materials, with the aim of optimizing this property in them. The research conducted is descriptive in nature, as an analytical method was used to characterize a physical phenomenon through its properties. Additionally, various classification criteria were considered to systematically organize the equations involved in the theory underlying this phenomenon.Publicación Estudio computacional de la transferencia de calor por radiación en campo cercano(Universidad EAFIT, 2023) Zambrano Corado, Yordani; David Caro, Jorge León; Jaramillo Ocampo, Juan ManuelThe objective of this research is to conduct a computational study of near-field radiative heat transfer (NFRHT), given the significant importance of this phenomenon in various technological applications. In order to implement new sensors or actuators with better performance than current ones, it is necessary to model the NFRHT phenomenon and observe its behavior in new materials, aiming to optimize this property in them. The research developed is descriptive in nature, as an analytical method was used to characterize a physical phenomenon through its properties. In addition, various classification criteria were considered to systematically organize equations involved in the theory underpinning this phenomenon.Publicación Spatial resolution enhancement in reflection and transmission digital holographic microscopy with structured illumination(Universidad EAFIT, 2024) Obando-Vásquez, Sofía; Trujillo Anaya, Carlos Alejandro; Restrepo, René; Doblas, AnaPublicación Diseño de un videojuego educativo con elementos de realidad virtual para la enseñanza de conceptos de física cuántica como el efecto fotoeléctrico aplicado en un entorno escolar(Universidad EAFIT, 2024) Jaramillo Jaramillo, Cristian Camilo; Diaz León, Christian AndrésThe importance of teaching quantum physics in secondary education lies in the need to familiarize students with scientific concepts that already influence our current technological environment. Additionally, the lack of motivation to study careers related to physics can be addressed by demonstrating the relevance of this area from early stages of education. Despite not completing the total development of the video game, virtual experiences, including the photoelectric effect experiment, managed to capture the attention and motivate the participants of the tests. It is recommended to expand the study with a larger sample and evaluate the long-term impact of the video game on student learning. This work provides a new perspective on the use of educational technology in teaching quantum physics in secondary education. The document presents the design of an educational video game created with Unity and virtual reality elements to teach concepts of quantum physics in secondary education, evaluating its effectiveness through Keller's Instrumental Material Motivational Survey (IMMS).Publicación Síntesis y caracterización de nanocompositos obtenidos a base de nanopartículas de magnetita-maghemita recubiertas con un polímero biocompatible(Universidad EAFIT, 2024) Páez Pinzón, Johan Sebastián; Velásquez Torres, Álvaro Andrés; Gómez Ramírez, Luis Alejandro; Urquijo Morales, Jeaneth Patricia; Síntesis y caracterización de nanocompositos de magnetita-maghemita para aplicaciones biomédicas, proyecto de investigación interno financiado por la Universidad EAFIT, código 11100012021. Programa “Conectando conocimiento 2019”, código de programa 70459.Publicación SEMAI Particle Analyzer(Universidad EAFIT, 2024) Restrepo Rivera, David; Quintero, Olga LucíaPublicación Measurements of urban aerosol properties by developing a scanning depolarization lidar system(Universidad EAFIT, 2022) Hoyos Restrepo, Manuela; Montilla Rosero, Elena; Universidad EAFIT; Ministerio de Ciencias de ColombiaPublicación Síntesis y caracterización de películas delgadas de Reb2 en Co-deposición con Ti mediante la técnica Magentrón Sputtering(Universidad EAFIT, 2023) Ruiz Daza, Carolina Rocío; Arroyave Franco, Mauricio; Palacio Espinosa, Claudia ConstanzaUsing the reactive magnetron sputtering technique, Rhenium Boride films in co-deposition with Titanium were grown on steel substrates at 100°C. To improve the adhesion of the coating a stack of twelve Ti/TiN bilayers was grown using a reactive atmosphere of argon and nitrogen with a ratio Ar/N2=40/1.4 sccm meanwhile, radio frequency power, negative bias voltage, working pressure, and temperature of 100°C were fixed in the experiments to produce the (ReB2):Ti. A design of experiments with a fraction-factorial style was made with four inputs and two outputs with 3 different levels. A matrix of procedures was defined for a total of 9 experiments. The titanium target was powered with 30 and 60 watts during the co-deposition with ReB2 to evaluate the content of titanium at different ratios. Structural and compositional measurements were carried out using SEM, XRD, and XPS to confirm the formation of (ReB2):Ti and AFM analysis to measure the thickness and observe the morphology of samples. Furthermore, mechanical properties were measured with nano hardness equipment, showing that the addition of titanium to ReB2 coating has a significant improvement on the chemical stability of ReB2 on steel and preserves mechanical properties of hardness and high Young’s module, which makes the material suitable for applications in the mechanical industry reaching hardness around 20 GPa.Publicación Evaluación computacional del efecto de los parámetros de proyección en las propiedades termocinéticas de las partículas en vuelo en la técnica de proyección térmica vía plasma usando Ansys Fluent(Universidad EAFIT, 2023) Álvarez Uribe, Alejandro; Palacio Espinosa, Claudia ConstanzaPublicación Control adapatable inteligente para exoesqueleto de rehabilitación(Universidad EAFIT, 2023) Ortiz Toro, Yarlin Andrea; Quintero Montoya, Olga Lucía; MinCienciasPublicación Development of a linear diattenuation sensitive semi-autonomous and portable digital lensless holographic microscope(Universidad EAFIT, 2022) Lopera Acosta, Maria Josef; Trujillo Anaya, Carlos Alejandro; G8 groupThis document presents the development of a linear diattenuation sensitive, semi-autonomous and portable digital lensless holographic microscope (DLHM). With the development of this project, we aim to improve the performance of this microscopy technique and to broaden the possibilities for a portable DLHM device. We believe our microscope can potentially be used in the diagnosis of diseases. In order to address this aim, the following aspects were investigated within the scope of this project. i) The design of specialized illumination sources for DLHM that are efficient, mechanically stable, and easy to align. ii) The implementation of a DLHM sensitive to the linear diattenuation response of samples. iii) The study of machine-learning based autofocusing methods to be applied to DLHM holograms. iv) The design of specialized software to acquire and reconstruct DLHM holograms and iiv) the design and manufacture of proper mechanical couplings that integrate the DLHM setup with the cellphone’s digital sensor. Five papers and five proceedings are the resultant products of this thesis project. They constitute part of the core of this thesis and are attached by the end of the document.Publicación Efecto de modificaciones de las cadenas carbonadas sobre el comportamiento elástico y de fase de bicapas lipídicas mediante dinámica molecular(Universidad EAFIT, 2022) Quintero Gómez, María Clara; Gómez Ramírez, Luis Alejando; David Caro, Jorge LeónPublicación Forest cover change detection with synthetic aperture radar satellite data(Universidad EAFIT, 2022) Guisao Betancur, Ana Maria; Marulanda Tobón, AlejandroPublicación Fabricación y caracterización de un fotoánodo de hematita para fotoelectrólisis(Universidad EAFIT, 2022) Herrera Guerra, Juliana; Jaramillo Ocampo, Juan Manuel; Montoya Isaza, Sebastián; Universidad EAFIT-Vicerrectoría de Descubrimiento y CreaciónPublicación Diseño y construcción de un sistema de medición de tasa de absorción específica (SAR) para sistemas de nanopartículas magnéticas(Universidad EAFIT, 2022) Ospina Duque, Ana María; Velásquez Torres, Álvaro Andrés; Velásquez Salazar, Abilo AndrésPublicación Miniaturización de antenas tipo microstrip mediante recubrimientos con materiales ferroeléctricos(Universidad EAFIT, 2021) Mosquera Palacio, Diana Marybel; Marulanda Bernal, José Ignacio; Universidad EAFITPublicación Efecto de los esfuerzos residuales sobre el comportamiento mecánico de componentes fabricados en acero sometidos a cargas cíclicas(Universidad EAFIT, 2021) Arango Gálvez, Juan Camilo; Palacio Espinosa, Claudia ConstanzaPublicación Computational aberration correction in optical coherence tomography with phase-unstable systems(Universidad EAFIT, 2020) Ruiz Lopera, Sebastián; Restrepo Gómez, RenéOptical coherence tomography (OCT) is an imaging technique widely use in medicine. OCT is an optical technique, therefore it is prone to optical aberrations that degrade image quality, making it difficult to visualize fine structures with high resolution.This work presents SHARP, a computational technique for correction of aberrations in OCT, that is compatible with most standard systems, and we present results in eye, airway and skin imaging
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