The structural colors, produced by leucophore and iridophore cells, are important for cephalopod camouflage; however, their scattering properties have not been very well studied. These colors are mainly due to the scattering of the specific small scatterers inside of the cell. In this work we will summarize the theories and the numerical methods used to solve both the scattering problems for one scatterer and a collection of such scatterers. The reflection spectrum of iridophores is shown to depend on both particle orientation and incident angle of the light. The leucophores are shown to be a white Lambertian surface. Therefore, starting from the structure of the cells, we can predict their color appearance in the skin. This work provides a general framework for the study of the structural color of cephalpods, and can be applied to many species with different cell structures.

Nanostructuring has led to materials with novel and improved materials properties driving innovation across fields as varied as transportation, computing, energy and biotechnology. However, the benefits of nanostructured material have not widely been extended into large-scale, three-dimensional applications as deterministic pattern techniques have proven too expensive for devices outside of high value products. This thesis explores how colloidal self-assembly can be used to form macroscopic functional materials with short-range order for electronic, photonic and electrochemical applications at scale. DNA-functionalized nanoparticles are versatile models for exploring colloidal self-assembly due to the highly specific, tunable and thermally reversible binding between DNA strands. Gold nanoparticles coated with DNA were used to investigate the temperature-dependent interaction potentials and the gel formation in DNA-colloidal systems. The electronic conductivity and the plasmonic response of the DNA-gold gels were studied to explore their applicability as porous electrodes and SERS substrates, respectively. Subsequently, silica nanoparticles were assembled into nanostructures that preferentially scatter blue light using both DNA and polymer-colloid interactions. Finally, rod-sphere structures made from DNA-coated gold nanoparticles and viruses were explored, demonstrating how high-aspect ratio building blocks can create composite structures with increased porosity. The gold-virus gel structures inspired the design and assembly of a silicon-carbon nanotube composite material using covalent bonds that shows promise for high energy density anodes.

Neste trabalho foram estudadas instabilidades magnetohidrodinâmicas (MHD) utilizando um novo sistema bolométrico que foi instalado no tokamak TCABR para medidas da evolução temporal da potencia irradiada. Este novo sistema conta com 24 cordas verticais, capazes de mapear toda uma seção poloidal da coluna de plasma com resolução espacial de aproximadamente 2 cm e uma resolução temporal de 20 _s. Como se sabe, as instabilidades MHD degradam o confinamento do plasma e modificam a topologia das superfícies magnéticas, causando a perda da energia do plasma. Por conta disso, compreender essas instabilidades é fundamental para o sucesso dos futuros reatores de fusão nuclear. As perturbações (oscilações) causadas pelas instabilidades MHD modulam diversos parâmetros macroscópicos do plasma como a densidade, a temperatura e a potencia irradiada. Então, utilizando o diagnostico bolométrico, _e possível medir as oscilações no perfil de potencia irradiada e, a partir deles, extrair informações importantes para determinar a origem e as características de tais instabilidades. No tokamak TCABR, as instabilidades foram caracterizadas através da analise espectral dos 24 sinais provenientes do novo sistema bolométrico. Para auxiliar a caracterização das instabilidades, um programa foi desenvolvido em Matlab para simular as medidas das perturbações no perfil de potencia irradiada. Através do mesmo procedimento de analise espectral, os resultados simulados foram comparados aos experimentais de forma que os parâmetros simulados, como largura e posição das ilhas magnéticas, fossem ajustados aos experimentais. Através dessa metodologia de analise, que combina simulação e experimento, foi possível caracterizar diversas instabilidades como o precursor dos dentes de serra e ilhas magnéticas de modos m = 2 e m = 3. / In this dissertation, magnetohydrodynamic (MHD) instabilities were investigated using a new bolometric system that was installed in the TCABR tokamak for radiation power measurements. This diagnostic is composed by 24 vertical chords that provide a full view of the poloidal cross section of the plasma column and provides spatial and temporal proles with approximately 2 cm space and 20 s time resolution. As it is well known, theMHD instabilities degrade the plasma connement and modify the magnetic topology, leading to energy loss from the plasma. Therefore, the understanding of these instabilities is essential for the success of the controlled thermonuclear fusion reactors. The MHD instabilities also cause perturbations (oscillations) in various macroscopic parameters, such as plasma density, temperature, and radiated power. Therefore, the oscillations in the radiated power prole measured by the bolometric diagnostic system provide a possibility to investigate the origin and features of the instabilities. In the TCABR tokamak, the instabilities were characterized by spectral analysis of the 24 vertical chords of the bolometric signals. In addition, a Matlab program was developed to simulate the integral characteristic of the oscillations in the radiated power measured by the bolometric system. The spectral analysis of the simulated signals is then compared with the spectral analysis of the bolometric signals. The simulated parameters, island width and radial position, were then adjusted to t the experimental spectrum results. Using this method of analysis, which combines experiment and simulation, it was possible to characterize various instabilities, such as sawtooth precursor and m = 2 and m = 3 magnetic islands.

Neste trabalho foram estudadas instabilidades magnetohidrodinâmicas (MHD) utilizando um novo sistema bolométrico que foi instalado no tokamak TCABR para medidas da evolução temporal da potencia irradiada. Este novo sistema conta com 24 cordas verticais, capazes de mapear toda uma seção poloidal da coluna de plasma com resolução espacial de aproximadamente 2 cm e uma resolução temporal de 20 _s. Como se sabe, as instabilidades MHD degradam o confinamento do plasma e modificam a topologia das superfícies magnéticas, causando a perda da energia do plasma. Por conta disso, compreender essas instabilidades é fundamental para o sucesso dos futuros reatores de fusão nuclear. As perturbações (oscilações) causadas pelas instabilidades MHD modulam diversos parâmetros macroscópicos do plasma como a densidade, a temperatura e a potencia irradiada. Então, utilizando o diagnostico bolométrico, _e possível medir as oscilações no perfil de potencia irradiada e, a partir deles, extrair informações importantes para determinar a origem e as características de tais instabilidades. No tokamak TCABR, as instabilidades foram caracterizadas através da analise espectral dos 24 sinais provenientes do novo sistema bolométrico. Para auxiliar a caracterização das instabilidades, um programa foi desenvolvido em Matlab para simular as medidas das perturbações no perfil de potencia irradiada. Através do mesmo procedimento de analise espectral, os resultados simulados foram comparados aos experimentais de forma que os parâmetros simulados, como largura e posição das ilhas magnéticas, fossem ajustados aos experimentais. Através dessa metodologia de analise, que combina simulação e experimento, foi possível caracterizar diversas instabilidades como o precursor dos dentes de serra e ilhas magnéticas de modos m = 2 e m = 3. / In this dissertation, magnetohydrodynamic (MHD) instabilities were investigated using a new bolometric system that was installed in the TCABR tokamak for radiation power measurements. This diagnostic is composed by 24 vertical chords that provide a full view of the poloidal cross section of the plasma column and provides spatial and temporal proles with approximately 2 cm space and 20 s time resolution. As it is well known, theMHD instabilities degrade the plasma connement and modify the magnetic topology, leading to energy loss from the plasma. Therefore, the understanding of these instabilities is essential for the success of the controlled thermonuclear fusion reactors. The MHD instabilities also cause perturbations (oscillations) in various macroscopic parameters, such as plasma density, temperature, and radiated power. Therefore, the oscillations in the radiated power prole measured by the bolometric diagnostic system provide a possibility to investigate the origin and features of the instabilities. In the TCABR tokamak, the instabilities were characterized by spectral analysis of the 24 vertical chords of the bolometric signals. In addition, a Matlab program was developed to simulate the integral characteristic of the oscillations in the radiated power measured by the bolometric system. The spectral analysis of the simulated signals is then compared with the spectral analysis of the bolometric signals. The simulated parameters, island width and radial position, were then adjusted to t the experimental spectrum results. Using this method of analysis, which combines experiment and simulation, it was possible to characterize various instabilities, such as sawtooth precursor and m = 2 and m = 3 magnetic islands.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21547号 / 理博第4454号 / 新制||理||1640(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 田中 耕一郎, 教授 前野 悦輝, 教授 山本 潤 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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The mapping of the refractive index of cells has been extensively studied since 1950s. This optical parameter constitutes a key biophysical property strongly correlated to fundamental cell parameters such, e.g., intracellular mass distribution and protein concentration. Experimental studies evidence that the cell refractive index (Refractive Index) provides critical insights to understand diverse cellular structures and interpret pathological states, including diverse stages of diseases. However, measuring the refractive indices of biological specimens satisfying clinical requirements is currently challenging, since there is a lack of spectral signatures of sub-cellular components in the visible range due to their transparent nature. Designing methods capable of extracting visible fingerprints of cellular components remains attracting large research interests. In this work, I have contributed to this project by fabricating and characterizing a black nanostructured membrane that dynamically interacts with cancerous cells and furnishes label-free structural color generation by exploiting the inherent contrast mechanisms of them. Thus, adequately meeting morphology differentiation to assist in biomedical research. I have tested the system with HCT116 colorectal cancer cells. In addition, this special membrane allows refractive index recovery and cell thickness mapping with commonly available bright-field microscopy equipment. Therefore, it is of considerable clinical importance to allow the generation of qualitative information about cell morphology to add in medicine and biophysics research.

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