Dissertations / Theses on the topic 'Photon addition'

L'objectif de ce travail est d'étudier un matériau up-converteur sous différentes formes afin de pourvoir l'appliquer au photovoltaïque (cellules de 3ième génération). L'oxyde d'yttrium possédant des propriétés particulièrement intéressantes pour l'up-conversion (gap et indice de réfraction élevés, faible énergie de phonons, dopage facile) a été choisi comme matériau up-converteur et a permis d'étudier les propriétés d'up-conversion de ce matériau sous formes de particules sphériques monodisperses et sous forme de couches minces. Les ions erbium et ytterbium, étant connus pour leurs très bonnes propriétés en up-conversion, ont été choisis comme dopants. Deux méthodes de synthèses : la synthèse par précipitation homogène et la synthèse par voie hydrothermale, ont permis d'obtenir les particules respectant les contraintes morphologiques prédéfinies. L'étude de ce matériau sous forme de particules a permis de déterminer l'influence des différents paramètres physiques et chimiques sur les propriétés d'up-conversion. Les couches minces d'oxyde d'yttrium ont été obtenues par spin-coating. L'étude de ces couches minces a permis de démontrer que les rendements de luminescence mesurés sur les couches sont beaucoup plus faibles que ceux des particules; cependant, la nanostructuration des couches minces a permis de démontrer une exaltation des propriétés de luminescence grâce à l'interaction des ions émetteurs avec les structures plasmoniques résonantes. Des études réalisées en vue de l'application de l'up-conversion au photovoltaïque (génération de courant dans une cellule bifaciale c-Si par excitation sub-band-gap, mesure en fonction de la température, up-conversion sous excitation solaire) ont démontré la faisabilité du concept et a permis de conclure que la réalisation du concept up-conversion/photovoltaïque doit encore passer par l'optimisation des matériaux up-converteur.

L'objectif de ce travail est d'étudier un matériau up-converteur sous différentes formes capable d'étendre l'utilisation du spectre solaire par les cellules photovoltaïques existantes. Y2O3: Er3+ (Yb3+) a été choisi comme matériau up-converteur et a permis d'étudier les propriétés d'up-conversion de ce matériau sous forme de particules sphériques monodisperses et sous forme de couches minces. Deux méthodes de synthèses : la synthèse par précipitation homogène et la synthèse par voie hydrothermale, ont permis d'obtenir les particules respectant les contraintes morphologiques prédéfinies. L'étude de ce matériau sous forme de particules a permis de déterminer l'influence des différents paramètres physiques et chimiques sur les propriétés d'up-conversion. Les couches minces d'oxyde d'yttrium ont été obtenues par spin-coating. La comparaison des propriétés de ces deux formes de matériaux a permis de démontrer que pour la même puissance d'excitation, les intensités de luminescence mesurées sur les couches sont beaucoup plus faibles que celles des particules; cependant, une étude réalisée sur la nanostructuration de couches minces d'YF3 a permis de démontrer une exaltation des propriétés de luminescence des couches minces, grâce à l'interaction des ions émetteurs avec les structures métalliques résonantes. Des études réalisées en vue de l'application de l'up-conversion au photovoltaïque (génération de courant dans une cellule bifaciale c-Si par excitation sub-bandgap, mesures en fonction de la température, up-conversion sous excitation solaire) ont démontré la faisabilité du concept.

Additive manufacturing is a fabrication approach which offers the possibility to build complex 3D structures from a virtual model without requiring moulds or costly post-processing steps to accom-plish the final structures. Digital Light Processing (DLP) and 2-Photon-Lithography (2PL), two lithog-raphy-based techniques, represent additive manufacturing processes, which offer the highest de-gree of achievable complexity and resolution in their printed structures. Both techniques print their 3D structures by using light to polymerise photosensitive materials. Photocurable preceramic poly-mer resins offer the possibility to be shaped by both DLP and 2PL printing and are subsequently transformed into ceramic material through pyrolysis, while maintaining their predetermined printed structure. This work is divided into four parts and presents complementary approaches at the material and production level to build highly complex 3D ceramic macro- and micro-structures, all based on the printing of a photosensitive siloxane preceramic polymer. In the first part the photosensitive polysiloxane is blended with other preceramic siloxane resins, of-fering no photosensitivity but a high ceramic yield upon pyrolysis. Complicated structures with cm-sized dimensions and resolution as low as 30 µm are shaped via DLP printing and turned into SiOC macro-structures with complete shape maintenance. The blending of two siloxanes offers the pos-sibility to control and alter the ceramic yield, shrinkage, resolution and free-carbon content of the structures, while at the same time exhibiting no diminished printing capability. Detailed sinter- and mechanical properties of one of the blends was investigated in detail and at all scales and demon-strated that, while the overall shape of ceramic structures are preserved during pyrolysis, different shrinkages as well as a change in aspect ratio depending on the structural configuration can occur and has to be taken into consideration. The photosensitive polysiloxane, already used for macro-fabrication to gain SiOC structures, was al-so used in 2PL printing to fabricate structures of the same complexity at the microscale. SiOC ce-ramics with homogenous shrinkage and feature sizes as low as 800 nm were built with the help of a new printing configuration and printed support structures. The third part of this work describes a complementary approach at the processing level, when SiOC ceramic structures are fabricated with a new hybrid additive manufacturing approach, combining DLP and 2PL printing. The advantages of DLP, the free standing and easy handling of macro-dimensional structures, are joined with the resolution capability of 2PL printing. Precisely positioned 3D structures with sub-µm sized features on top of cm-sized structured components were printed. In the final part the polymer processing capability of preceramic polymers and their transformation into a reactive ceramic phase upon pyrolysis is exploited. Instead of producing pure SiOC ceramics, the photocurable siloxane preceramic polymer is combined with alumina powders to develop a new ceramic phase, mullite, upon sintering. The phase transformation at low sintering temperatures de-veloped the new mullite phase within the 3D structure, fabricated due to the photosensitive capabil-ities of the siloxane via DLP printing. Due to the complementary approach in this work, 3D ceramic structures have been fabricated at the macroscale (DLP), microscale (2PL) and multi-scale (Hybrid additive manufacturing; DLP + 2PL) on basis of a photosensitive preceramic polymer. Different ceramic materials, SiOC and mullite, have been produced from the polysiloxane thanks to its transformation capability into SiOC ceramic and reactive SiO2 phase at high temperatures. Through the addition of passive and active fillers complex, dense, pore- and crack-free ceramic structures with no sign of delamination and complete mainte-nance of shape have been developed with varying properties.

Des sources lumineuses sont, a ce jour activement recherchees a 1,3 m pour augmenter la capacite des reseaux de telecommunications par fibres optiques. Pour cela, des compositions de verres dopes aux terres rares et optimises du point de leurs proprietes optiques sont necessaires. Les verres de chalcogenures ayant des indices de refraction eleves et une transparence dans l'infrarouge qui s'etend au-dela de 10 m possedent les qualites necessaires pour operer a cette longueur d'onde. Les verres de chalco-halogenures, avec les elements ge-ga-s-csx ou x = c1, br, i ont ete synthetise au laboratoire. L'ajout d'un halogenure au verre de chalcogenure se traduit par une amelioration de la stabilite thermique et un elargissement du domaine de la transparence dans le visible sans changer les caracteristiques dans l'infrarouge. Ces verres possedent, par ailleurs, une bonne solubilite des ions de terre rare. Ils ont ete dopes par les ions nd 3 + et pr 3 +. Les proprietes physiques et optiques (temperatures caracteristiques, densite, indices de refraction, transmission uv et ir) de ces verres ont ete mesurees et comparees avec celles de verres de sulfure classiques. La theorie de judd-ofelt a ete employee pour la comprehension des mecanismes des transitions 4f-4f dans ces verres. Cependant, les verres de chalcogenures posent des problemes pour l'application de cette theorie du fait du bandgap qui occulte les bandes d'absorption de haute energie des ions de terre rare. Quelques methodes nouvelles ont ete testees pour appliquer la theorie de judd-ofelt dans les verres de chalcogenures. Les emissions des ions nd 3 + et pr 3 + ont ete etudiees dans les verres ga-ge-csx, en fonction de halogene x et en fonction de la concentration en ions de terre rare. Concernant la neodyme, les spectres d'emission ir du niveau 4f 3 / 2 et les emissions visibles de ( 4g 7 / 2, 2k 1 3 / 2, 4g 9 / 2) ont ete enregistres et les durees de vie mesurees. Les processus d'esa a partir de 4f 3 / 2 qui contribuent a reduire l'emission a 1,3 m de nd 3 + ont ete egalement enregistre. Concernant le praseodyme, les spectres d'emissions ainsi que les durees de vie des niveaux 1g 4 (transition a 1,3 m), 1d 2 et 3p j ont ete mesures une part important de ce travail a ete consacre a la mise en evidence et a la caracterisation des processus d'addition de photons vers les niveaux ( 4g 7 / 2, 2k 1 3 / 2, 4g 9 / 2) de nd 3 + et vers les niveaux 1d 2 et 3p j de pr 3 +.

La photochimie occupe une part de plus en plus importante en chimie organique, permettant d’obtenir dans des conditions douces un grand nombre de composés difficilement accessibles par les méthodes classiques. Au cours de ce travail, nous nous somme intéressé à différents aspects de la réactivité photochimique de dérivés de furanone. L’irradiation de furanones fonctionnalisées par le tétrahydropyrane et le glycose en présence de l’acétone comme sensibilisateur conduit par un mécanisme de transfert d’énergie à une réaction radicalaire intramoléculaire régiosélective où l’addition se fait en position α de la furanone. Une étape importante dans ce mécanisme est l’étape d’arrachement d’hydrogène. Une réaction d’épimérisation est mise en évidence au niveau du centre anomérique des composés β-anomères. Ce type de réaction photochimique permet d’accéder de façon contrôlé à des structures hautement fonctionnalisés (une famille de carbasucres). Nous avons réalisé une addition sélective en position α du composé carboxylé α,β-insaturé par un transfert mono-électronique via la formation d’un exciplexe ou d’une paire radicaux d’ions en contact. Le mécanisme de cette réaction est mis en évidence par un marquage au deutérium et la discussion de la régiosélectivité. Ce marquage nous a permis de découvrir l’origine de l’hydrogène additionné en position β de la furanone. Les structures accessibles par cette méthode peuvent avoir des propriétés anti-inflammatoires, analgésiques et antipyrétiques bactéricides et diurétique
Photochemistry plays an increasing role in organic chemistry, as a powerful approach to obtain under mild conditions a large number of compounds inaccessible by conventional methods. During this work, we looked at different aspects of the photochemical reactivity of furanone derivatives. Irradiation of furanones functionalized by tetrahydropyran and glucose in the presence of acetone as sensitizer led by a mechanism of energy transfer to a regioselective intramolecular radical reaction where the addition occurs in α position of the furanone. An important step in this mechanism is the hydrogen abstraction. A reaction of epimerization was shown at the anomeric center of β-anomers molecules. This type of photochemical reaction can be controlled to prepare highly functionalized structures (a family of Carba-Sugars). We have carried out a selective addition at a α-position of α,β-unsaturated carbonyl compound by a single-electron transfer via the formation of an exciplex or radical ion pair in contact. The mechanism of this reaction was revealed by a deuterium-labeling and interpretation of the regioselectivity. The isotopic-labeling allowed us to discover the origin of hydrogen added in β position of a furanone. Structures accessible by this method may have anti-inflammatory, analgesic, antipyretic and diuretic as well as bactericidal activities

Ce mémoire se compose de deux parties, la première consacrée à l'étude des processus multiphotoniques se produisant dans des fibres optiques fortement dopées avec des ions er3+ et yb3+, et la seconde à l'étude des défauts induits par différents traitements dans des fibres germanosilicates. En étudiant la spectroscopie d'émission des fibres fortement dopées, sous excitations visibles (488 nm) et infrarouge (790 - 880 nm), nous mettons en évidence les différents mécanismes aux émissions bleues, vertes et rouge observées. Deux principaux types de processus d'up - conversion peuvent alors être distingués : ceux faisant appel aux transferts d'énergie Yb er et ceux faisant intervenir le phénomène d'absorption dans l'état excité (ESA). L'influence de la longueur de fibre et des concentrations en ions de terre rare sur les efficacités respectives de chacun de ces deux mécanismes est ensuite abordée. Après une présentation bibliographique des différents défauts dans la silice et les fibres germanosilicates, nous présentons le phénomène appelé dépendance modale du spectre d'émission d'une fibre optique, c'est-à-dire la variation du spectre d'émission d'une fibre en fonction du mode excité. L'évolution avec la température d'une bande d'émission centrée autour de 600 nm nous permet ensuite d'attribuer cette émission à des radicaux péroxys. Nous montrons alors que ces radicaux péroxys peuvent être photoinduits dans le CUR des fibres par irradiation intense à 488 nm. Enfin, nous étudions par spectroscopie Raman et spectroscopie d'émission les défauts générés dans deux types de fibres germanosilicates irradiées à 240 nm. Une technique de filtrage spatial du mode excité permet alors de séparer les défauts photoinduits dans le CUR de ces fibres de ceux localisés près de l'interface CUR/gaine

Ce travail de thèse s’inscrit dans le contexte identifié de la nécessité de développer de nouveaux polymères plus respectueux de l’environnement. Nous sommes convaincus que l’essor de ces matériaux « verts » exige d’utiliser des additifs « verts » lors de la formulation. Dans le but d’élaborer des additifs respectueux de l’environnement capables d’assurer la stabilisation du polymère au regard du cycle de vie, et en attachant une attention particulière à la valorisation de la biomasse, trois approches ont été étudiées. La première est une voie innovante qui consiste à utiliser un mélange de polyphénols issus des sous-produits de l’industrie vinicole, et de l’industrie du thé. La seconde voie est la valorisation d’une molécule issue du sous-produit majeur de l’industrie du blé. La troisième est une voie d’innovation récente, qui propose l’utilisation de nanocomposites hydroxydes doubles lamellaires (HDL) fonctionnalisés avec des stabilisants biosourcés. L’évaluation de leurs propriétés stabilisantes, est réalisée au regard des processus de thermo- et photo-oxydation, dans les polyoléfines. Les résultats très prometteurs de ce projet mettent en évidence le fort potentiel des molécules et composites d’origine biosourcée à maintenir les propriétés des polymères en conditions d’usages
This thesis work falls within the identified context of the need to develop new polymers that are more environmentally friendly. We are convinced that the development of these "green" materials requires the use of "green" additives during formulation. To develop environmentally friendly additives capable of stabilizing the polymer, with respect to the life cycle, and paying special attention to biomass valorization, three approaches have been studied. The first is an innovative way of using a mixture of polyphenols from winery by-products and tea industry. The second way is the valorisation of a molecule from the major by-product of the wheat industry. The third is a recent route of innovation, which proposes the use of layered double hydroxides nanocomposites (LDH) functionalized with bio based stabilizers. The evaluation of their stabilizing properties is carried out in polyolefins, against thermo- and photo-oxidation processes. The very promising results of the project highlight the strong potential of bio based molecules and composites to maintain polymers properties under conditions of use

A percepção e interpretação da interação de indivíduos e populações com o ambiente e a forma como tal relação condiciona sua distribuição espacial é questão-chave e recorrente em estudos ecológicos. Padrões de uso de área observados para populações emergem em ultima análise da variabilidade entre seus indivíduos em selecionar habitats e interagir com os mesmos. Este estudo teve como foco o uso de área pela população do boto-cinza, Sotalia guianensis, e sua variabilidade individual no estuário de Cananeia, localizado na costa sudeste do Brasil (25°03\' S; 47°55\' W), durante o verão e o inverno de 2015 e o verão de 2016. Parâmetros ambientais e geográficos (distâncias da desembocadura de rios, da entrada do estuário e de áreas urbanas, profundidade, maré e autocorrelação espacial) foram testados para explicar a distribuição da população e de seus indivíduos a partir de funções de probabilidade de seleção de recursos (RSPF) em modelos aditivos generalizados (GAM). Onze indivíduos fotoidentificados com 18 ou mais recapturas foram avaliados com o uso de modelos individuais de ocupação e sua interpretação foi subsidiada por estimativas de áreas domiciliares obtidas a partir de kerneis fixos de densidade. Nas três temporadas a população apresentou densidades de grupos desiguais ao longo do estuário e todas as variáveis, com exceção da distância de áreas urbanas, explicaram as probabilidades de presença observadas. Análises individuais revelaram discrepâncias nos tamanhos e disposição geográfica de áreas domiciliares e diferenças na composição e estimativa dos parâmetros selecionados para cada indivíduo. A variabilidade individual na população deve ter papel fundamental em termos de utilização do espaço e seleção de habitat pelo boto-cinza no estuário local.
Understanding and interpreting the interaction of individuals and populations with the environment and how this relationship outlines their spatial distribution is a key question common in ecological studies. Area use patterns observed for populations are ultimately an outcome from individual variability in habitat selection and their interaction with such environments. Are use and habitat selection by the population of Guiana dolphins, Sotalia guianensis, and its individual variability were accessed in the Cananeia estuary (25°03\' S; 47°55\' W), southeastern Brazil, during the summer and winter of 2015 and the summer of 2016. Environmental and geographic parameters were estimated aiming to explain population distribution and differences within individuals. For this purpose, resource selection probability functions (RSPF) were applied in generalized additive models (GAM). Covariates tested included: distance to river mouths, distance to the estuary entrance, distance to urban areas, depth and tide. Geographic coordinates were used to model spatial autocorrelation. Eleven photo-identified individuals had their occupancy modelled and accessed in relation to their home range obtained from fixed kernel densities estimates. The population exhibited patchy group densities throughout the estuary in all seasons. Except from distance to urban areas all variables were selected in our final model for the population\'s RSPF. Individual analysis revealed discrepancies in size and location of home ranges which lead to remarkable differences in the composition and estimates of parameters selected in the models for each individual.

In this thesis work, after a brief introduction of some basic concepts of quantum optics, some experimental techniques useful for the manipulation of quantum states of light are presented. In particular, I focused on two transformations operated at the single-photon level, like the addition and the subtraction of a single photon from a travelling light beam. Both these methods share a probabilistic approach, that is their implementation has a non unitary success probability. Anyway, the detection of an additional photon in an ancillary mode exactly announces when the operation has been actually implemented. That's why this type of implementation is generally called heralded. Starting from these basic operations, a way to implement some of their superpositions is then analyzed. In the second part of this thesis, I describe two state-engineering experiments based on these fundamental operations. The first one realizes a so-called universal orthogonalizer, an universal strategy that, given an arbitrary input state, can be used to produce at the output an orthogonal one. The adjective universal refers to the fact that the procedure works equally well for arbitrary input fields. The other experiment uses coherent superpositions of basic quantum operations to emulate a strong Kerr nonlinearity at the few-photon level, and could be used to implement new logic gates for quantum computation. The third part of this thesis is dedicated to a different experimental approach, in some sense complementary to state engineering: mode engineering. Indeed, while in state engineering the purpose is the detection of an unknown state after its manipulation, in mode engineering experiments the perspective is completely reversed: the final state is assumed to be known and what has to be inferred are its spatio-temporal features. By following this alternative experimental approach, the interaction of broadband single photons with resonant atomic vapours is analyzed by observing the traces left on the photon temporal shape.

碩士
國立交通大學
機械工程系所
105
This thesis introduces the practical issue of two-photon polymerization platform via utilization of the photoresist to fabricate two-dimensional or three-dimensional structures. The feasibility of accelerated polymerization by using laser-scanning system is discussed. The whole system is divided into the optical and microscopy system. Titanium sapphire femtosecond laser, centered at 800 nm, is used as the light source in the optical system. A half wave plate and polarizer are used to control the power. The pulse duration is compressed to be ~ 95 femtosecond in front of the sample. The switch of the light source is achieved by an acousto-optic modulator. The microscopy system includes an inverted microscope, incorporated with a galvanometer mirrors for two-dimensional laser scanning. The depth dimension of the structure is controlled by a motorized stage and monitored with a confocal system. By controlling the laser power and writing speed, this two-photon polymerization platform is capable of writing the structures on the sample (photoresist on substrate) with different resolution (linewidth). The resolution of the polymerized structure can be achieved by suitable light dosage, which just exceeds the threshold of polymerization. The optimal resolution (minimum linewidth) achieved in this thesis is 190 nm.

碩士
國立臺灣師範大學
化學系
103
Perovskite solar cells have been developed rapidly in recent years. Solution processable planar heterojunction perovskite solar cells are seen as a promising low-cost renewable energy technology. The most common device structure is FTO / TiO2 / CH3NH3PbI3-xClx / spiro-OMeTAD / Au. The main difficulties for this type of solar cells are the controls of coverage and morphology of perovskite CH3NH3PbI3-xClx film. In this study, a solution processable pyrite iron(II) sulfide nanocrystals (FeS2 NCs) act as additives. The FeS2 NCs mixed solution is added 5 vol% into the perovskite precursor solution to improve the film formation, the energy conversion efficiency reach 15.95%. Compared with the pristine CH3NH3PbI3-xClx device it has enhanced about 28%. We studied the new perovskite by various analyses, including XRD, Visible Absorption Spectroscopy, EQE, TRPL and SEM. The results showed that this iron(II) disulfide nanocrystals additive can improve the crystallinity of the perovskite film, making it more connective and directional. Therefore, the increased VOC and FF further enhanced the energy conversion efficiency of perovskite solar cells.

碩士
國立中興大學
機械工程學系所
106
This study proposes a novel method for fabricating the diffraction grating by using the 3D printing. In the former researches, the fabrication of diffraction grating was complex and challenging. Therefore, it is innovative and creative to investigate the feasibility of fabricating the diffraction grating based on the 3D printing technology. The 3D printing is also called additive manufacturing (AM), which has been developing rapidly in recent years, and is now widely used in various fields. However, it is restricted by poor resolution and difficult to be applied to the printing of microelement so far. Traditionally, the grating fabrication requires complicated processes and expensive equipment. Therefore, this study investigates the feasibility of fabricating microoptical elements based on the technology of photo-polymerization 3D printing. By converging blue laser light to get a small focusing spot, the grating pattern can be scanned and printed. The manufacturing processes of microoptical elements could be effectively decreased. Experiments were divided into two parts. One is the printing resolution verification and the other is the 3D printing using a blu-ray optical pickup head. Regarding to the printing resolution verification, print lines of 5 m in width have been achieved. As for the configuration of using a blu-ray optical pickup head for printing a grating structure with ten layers deposition has been successfully printed. Based on the fabricated grating period, the diffraction efficiencies were simulated by the grating analysis software (G-solver). Finally, the efficiencies of diffraction orders were measured for the fabricated grating. They were compared with the simulated values. The results show that the measured data are close to those of simulation. It reveals that fabricating the diffraction grating by the stereo lithography apparatus technology is possible.

Additive manufacturing using 2 photon polymerization is of great interest as it can create nanostructures with feature sizes much below the diffraction limit. It can be called as true 3D printing as it can fabricate in 3 dimensions by moving the laser spot in any 3D pattern inside the resist. This unique property is attributed to the non-linearity of two photon absorption which makes the polymerization happen only at the focal spot of the laser beam. This method has a wide range of applications such as optics/photonics, metamaterials, metasurfaces, micromachines, microfluidics, tissue engineering and drug delivery.
This work focuses on utilizing 2 photon fabrication for creating a metasurface by printing diabolo antenna arrays on a glass substrate and subsequently metallizing it by coating with gold. A femtosecond laser is used along with a galvo-mirror to scan the geometry inside the photoresist to create the antenna. The structure is simulated using ANSYS HFSS to study its properties and optimize the parameters. The calculations show a reflectance dip and zero reflectance for the resonance condition of 4.04 μm. An array of antennas is fabricated using the optimized properties and coated with gold using e-beam evaporation. This array is studied using a fourier transform infrared spectrometer and polarization dependent reflectance dip to 40% is observed at 6.6 μm. The difference might be due to the small errors in fabrication. This method of 3D printing of antenna arrays and metallization by a single step of e-beam evaporation is hence proved as a viable method for creating optical metasurfaces. Areas of future research for perfecting this method include incorporating an autofocusing system, printing more complicated geometries for antennas, and achieving higher resolution using techniques like stimulated emission depletion.

碩士
高雄醫學大學
醫藥暨應用化學系碩士班
106
Polyurethane (PU) is a common resin in the photo-curing 3D printing system. In this study, synthesized by the two-step polymerization method with different properties of polyurethanes, then PU mixed photoinitiator to form a bond by light, and NIPAAm was added to enhance the mechanical strength and elasticity. Finally, printing three-dimensional structure by the photo-curing 3D printer. The structure and properties characterized by Thermogravimetric analysis (TGA),and tensile tests. Photo-curing polymerization technology is a printing method that uses a specific wavelength to illuminate a liquid resin to produce a photopolymerization reaction to form a complex shaped object. Polyurethane (PU) is a high molecular weight polymer composed of polyurethane-linked organic monomers, which are usually synthesized by diisocyanates or polyisocyanates and polyols to changing the composition of the hard segments in PU. It has excellent mechanical properties, low cost, and environmental protection. Preliminary studies have shown that although the compressive strength after curing with NIPAAm is lower (60.11 MPa), the ductility is better (Strain = 17.83%). On the other hand, the compressive strength after the addition of water was the best (151.58 MPa), but the ductility was poor (Strain = 7.17%). This study can synthesize different mechanical properties according to the requirements.

碩士
國立臺灣科技大學
機械工程系
104
Photo-curing process has the best accuracy in additive manufacturing. In order to make the workpieces have the applications on conduct electricity and magnet permeability, the particles mixed with resin must cause the accuracy and forming problem. Recently, many researches shows that they have mixed graphene and magnetic powder in polymers, using Fused-Deposition Modeling process to heat the materials and form the workpieces, achieving the requirements of conduct electricity and magnetic permeability. This research mix ferrite oxide powder in bio-resin, investigating the forming parameters and make the photo-curing biomaterials refer in the future. Considering the biochemical issue, this research use physical rapid stirring method, collocating with the viscosity of two biomaterials to let the particles mixed and suspension in the resin. Then discuss the influence of manufacturing time between maximum concentration of ferrite oxide and different present of photoresist. After investigating the accuracy of forming parameters and forming features, arranging the better formula and analysis the magnetic permeability of all pieces made by two different type of biomaterials. Finally, use the biodegradable material to make complicated, multi-layer structure, which is used to form the bio-scaffolds. According to the experiment, the lower concentration of ferrite oxide powder with 3% of photoresist TPO, the better accuracy of workpiece. The requirement of higher magnetic permeability, the higher concentration, 3% ferrite oxide powder with acceptable accuracy, can results the better magnetic applications.

碩士
國立中興大學
機械工程學系所
106
The additive manufacturing technology (so called ‘3D printing’) has been developed since the 1980s, and changed to various systems for different situations and purposes. However, no matter which 3D printing system it is, the nozzles or laser modules for structure molding are very expensive. That subsequently makes the price of 3D printers hard to be reduced. Therefore, this study proposes an optical projection system design which applies the smartphone or flat panel display as the light source. With the core configuration, the novel photo-polymerization 3D printing apparatus could be realizes. This research designs a projection imaging system using two concave mirrors to converge the diverged light from the screen of a smartphone into the image plane, where a floating image can be formed. It is focused at the bottom of a resin tank and has the same pattern as that displayed on the screen. This pattern can make photosensitive resin photo-polymerized. After z-direction shifting, a three-dimensional structure can be printed. The system can keep, enlarge, or shrink the original pattern size on the screen. Based on the theoretical derivation, the magnification of the projection system is related to the focal length ratio of concave mirrors. By means of suitable focal length combination, this system can overcome limitations from smartphone, such as the resolution and size of production. First, the image formation of the projection system was simulated and the relation between the system setup and imaging quality was investigated. Secondly, three patterns were designed for proceeding to the 3D printing experiments. The experiments were performed by three types of the non-imaging system, imaging system of equivalent focal lengths, and imaging system of unequal focal lengths. The printing thickness per layer is set to be 100 μm. According to the results, the most suitable printing time of each layer for three systems are 10 seconds, 1 minute, and 2.5 minutes, respectively. The optical projection imaging systems proposed in the study effectively converge the diverged light from the smartphone and photo-polymerize the visible-light resin by focused patterns. Finally, the three-dimensional objects were successfully printed. By adopting precise aspherical mirrors and lens, the quality of printed objects could be well improved in the future.

碩士
國立臺灣科技大學
機械工程系
106
At present, tissue engineering still uses single-material scaffold for vitro cell culture, but lack of the nutrients, oxygen and protein in cell growth causes the micro-environment can’t simulate the human body. By the combination of different material properties, a scaffold can be prepared to match different cell types and provide the functional environment. Therefore, this study established a multiple-material DLP system, research the bonding effect of different materials, and study on multi-material scaffold for cell culture. The DLP process is applied to produce a multiple-material scaffold with high precision and install a tank-changing mechanism is more convenient to change the material in the printing process to avoid the vibration of the machine.PGSA60+PCL-DA and PEG-DA were selected to test the difference in properties between the materials. The gap of interface and defect were found during the printing process, resulting in stress concentration and reduced loading capacity. It has been found that the curing depth of the bonding surface PEG-DA to 140 μm can effectively increase the bonding ability and print a precised scaffold with different materials.Through the implantation of Hepatocyte and HUVECs into the scaffold, it was found that the cells maintained good biocompatibility during the culture. In addition, in order to increase the stability of vascular material PEG-DA immersion in water and the ability of molecular diffusion, PGSA has been added to formulate, and it is expected that the process and materials will be more widely application in in the tissue engineering.

A first measurement of pp -> Wγγ+X production cross section and the process of vector boson scattering producing Wγ, using the 20.3fb-1 dataset collected by the ATLAS detector from the proton-proton collisions at the Large Hadron Collide (LHC) located in CERN, are presented in this thesis.

Dissertation

碩士
美和科技大學
生技科技系健康產業碩士班
103
We have established an in vivo test platform to detect the changes of protein carbonylation in the most outer layer of human stratum corneum (SC). The platform can be applied to evaluation of the photo-protective capability of antioxidants and UV filters, respectively. In this study, we identified the additive photo-protective efficiency of various combinations of vitamins E/C and UV filter by the in vivo test platform. An oil-in-water emulsion delivery was used, and a fixed concentration of antioxidant and UV filter in the tested emulsions was 0.3 %, and 2.5 %,, respectively. Five healthy male volunteers participated in each emulsion, and in a single blind test manner. The rear-side skin of the forearm was divided equally into experimental and control areas. Topical application was administered once at a dosage of 3.0±0.2 mg/cm2 in the morning, and exposed sunlight with an accumulative time of 12 min every day during the test period of 2 weeks. The results indicated that the photo-protective efficacy of -Vit E was significantly better than Vit C. The photo-protective efficacy of Butyl methoxydibenzoylmethane (BMDM) was significantly better than Octyl methoxycinnamate (OMC) and Octocrylene (OCR). The combination of antioxidant and UV filter, only-Vit E and BMDM represented additive effect, other combinations represented insignificant additive effect. We believed that an antioxidant has the properties with poor oxidation stability and poor photostability, it is not ability to promote the additive photo-protective efficiency in the presence of UV filter through the use of a low concentration and sunlight exposure conditions. In addition, the interaction between antioxidant and UV filer is an important factor in the additive effects for photo-protective efficiency. Our data suggested that the platform set up in the current study can be potentially used for quantifying the photo-protective efficiency of the combination formulation of antioxidant and UV filter.

Dottorato di Ricerca in Scienze e Tecnologie Fisiche, Chimiche e dei Materiali. Ciclo XXX
In the field of nanotechnologies the Two-Photons Direct Laser Writing (TP-DLW) is the most advanced optical technique for creating arbitrarily complex 3D structures in organic resists, featuring details down to 50 nm, well below the diffraction limit. More recently, this technique has been used in “resists” containing a photosensitive metallic precursor, activated by the two-photon absorption (TPA) process, allowing for the creation of metallic nanoparticles clusters inside to the focus figure of a highly focused laser beam, where the TPA threshold intensity is reached. The aim of my PhD work was the elucidation of the physical processes involved in the realization of 3D nanostructures made in different materials for applications in micro-fluidics and advanced optics. In particular, I carried out studies on both isotropic and anisotropic photoresists, and on metallic precursors. Concerning the isotropic photoresists, I have investigated the capabilities and the limits of the TP-DLW technique, on the fabrication of microfluidic systems and elements of millimetric size, with micro- and nano-features printed inside the channels. The best results in printing such millimetric structures in terms of geometrical compliance and fabrication time are achieved, by combining the single (SPA) and the two-photon absorption (TPA) processes. The latter one allowed for the creation of a shell, an internal structural scaffold and eventual microscopic details, whereas the former one to polymerize the bulk of the object. However, the development step of microfluidic systems (i.e. the removal of the un-polymerized resist) is quite challenging in general, due to possible swellings and consequent distortions in the structure geometry. In my PhD, I developed an effective protocol to face this issue. The application of the TP-DLW technique to anisotropic reactive mesogens (RMs) resulted in very interesting achievements, as it allowed for the fabrication of 3D solid structures, maintaining the optical properties of liquid crystals, in combination with the mechanical properties of polymers. Effects of the direct laser writing on the internal molecular order of the reactive mesogens have been thoroughly investigated, to ensure a fine control on the optical properties of 3D objects made in liquid crystalline elastomers. Analyses of the physical processes, which occur during TP-DLW and allow for tuning of the optical response of the printed 3D solid structures are shown. Appropriate doping of the reactive mesogens with dyes and chiral dopant agents were performed to investigate different fields of applications. In particular, a chiral agent confers helical order to the RMs, which show selective Bragg reflection of the impinging light in both wavelength and polarization. Micro-fabrication of 3D chiral structures is a brand new field that is paving the way to the creation of photonic devices, such as micro-laser of defined shape, white light reflective object, anti-counterfeiting and data storage systems. I performed a series of experiments aimed at demonstrating the possibility to manipulate the helical structural order of the liquid crystals during TP-DLW. As a consequence, multi-colour three-dimensional structure can be created. Finally, the possibility to include metallic details in polymeric objects or even to create metallic structures would pave the way for the DLW of metallic/polymeric nano-composites. I performed experiments with polymeric or hydrogel matrices doped with a suitable metallic precursor, in a free surface drop cast, or in cell segregated thin film, onto a glass substrate. In such system, I was able to create 1D gratings made of GNPs stripes with single or multiple laser sweep. I demonstrated that the stripe width increases with the laser power and the exposure time, showing a behaviour similar to the photo-polymerization, as expected. I also analysed the influence of the exposure time over the nano-particles size distribution and density and showed that by suitably adjusting the exposure time it is possible to maximize the occurrence of a given diameter. The experiments were aimed at elucidating the involved physical phenomena, beyond the bare optical absorption. In particular, the key-role of thermal and diffusive processes have been analysed. TPA leads to the photo-reduction of ions of AuCl4 – and the creation of GNPs, but to a local heating of the sample as well. Due to the very fast heating, a thermal shock-wave is generated and is responsible of the local dehydration in the spot area. Due the concentration gradients of the ions of gold precursor and of water, different diffusive processes take place, occurring on different timescales. Therefore, different characteristic times are observed for the ion and the water diffusion, in the polymeric matrix. My experiments demonstrate that the diffusive effects can be exploited for controlling the NPs density and size when a given energy dose is delivered in multiple shots, by tuning the time interval between each shots. Preliminary experiments on the possibility to control the growth of GNPs through the application of specific electric field during TP-DLW were performed as well. Last but not least, the possibility to use TP-DLW of metal precursor to realize smart platform rich in GNPs suitable to different application is shown. In particular, I demonstrate that, controlling the pitch and the size of GNPs stripes, it is possible to create both thermo-platform whose thermal response to external light is tuneable, and detecting substrates for Surface-Enhanced Raman Spectroscopy (SERS). The Raman spectra were recorded from samples immersed in a solution of rhodamine-6G (R6G), as well as, after exposure of the samples in xylene. SERS enhancement factors of up to ~104 were obtained for both rhodamine-6G and xylene.
Università della Calabria

碩士
國立臺灣科技大學
機械工程系
105
Currently, the treatment of liver disease is by organ transplantation, but the risk of surgery and the shortage of liver supplement are still the drawbacks that can’t be overcome. Although utilizing tissue engineering can repair the damaging part of liver directly, but there are still some restricts on material and manufacturing process. So is still hard to fabricate a scaffold like a real liver. This study focuses on this two issue that mentions above. We want to develop a biomaterial that combines with both mechanical strength and biocompatibility, and use dye to improve the accuracy of the scaffold to match liver tissue. This study is based on photocurable PCL-DA, and blend with PEG-DA/PGSA to improve the hydrophilic. By tensile test, contact angle test, DSC, and TGA, we check the properties of the material in different concentration. After the material with similar properties was found out, we utilized the DLP-AM system to fabricate the liver scaffold and culture Mouse Liver FL83B Cells on the scaffold to check the cell activities and biocompatibility. The result shows that PCL-DA+PGSA60 1:2 had a better performance in both mechanical strength and biocompatibility and it’s safe to utilize in the human body. In formability, we replaced Phthalocyanine Blue to Sudan Black B for the application in preventing over-curing to fabricate tissue engineering scaffolds. The result shows that in dying concentration 0.04wt% the dimension accuracy can be controlled within 8% and the biocompatibility is good.

碩士
國立臺灣科技大學
機械工程系
102
Additive Manufacturing (AM) technologies have been applied to fabricate tissue engineering scaffolds nowadays to solve issues such as pore-size control and geometry shapes in traditional methods. Most AM approaches utilize extrusion or sintering, yet few by photo-curing. In the previous research in our lab, preliminary study on photo-curable PCL material (PCL-DA) combining with PEG-diacrylate (PEG-DA) cured by Dynamic Masking Rapid Prototyping System was conducted, but material properties are not well understood. Besides, the over-curing issue of the material limited the number of layers being fabricated. Therefore, in this research, more material properties were investigated, and fabrication capability were improved. Three ratios (6:4, 7:3, 8:2) of PCL-DA to PEG-DA were studied. Thermal analyzer equipments (TMA, DSC, and TGA) were used to determine the coefficient of thermal expansion of the materials and understand their thermal stability. Degradation tests revealed weight loss and pH value of materials within 60 days. Moreover, the L929 cells were cultures in vitro on the cured PCL-DA/PEG-DA thin-film to observe biocompatibility. The results from SEM observation and MTT tests proved cell adhesion and growth on the cured materials. Besides, in order to improve scaffold fabrication capability, two strategies were proposed to eliminate over-curing issue of transparent materials—multi-pattern geometry design and dyed materials. The multi-pattern design can provide various sizes of connecting pores for cells growth, but the effects on avoiding over-curing is limited. On the other hand, dyed materials can block the light to over-cure previously cured layers effectively and increase the stackable numbers of layers from 8 to 20 and more. The scaffold fabrication capability has successfully been improved.

A variety of methods have been developed to enhance solid propellant burning rates, including adjusting oxidizer particle size, modifying metal additives, tailoring the propellant core geometry, and adding catalysts or wires. Fully consumable reactive wires embedded in propellant have been used to increase the burning rate by increasing the surface area; however, the manufacture of propellant grains and the observation of geometric effects with reactive components has been restricted by traditional manufacturing and viewing methods. In this work, a printable reactive filament was developed that is tailorable to a number of use cases spanning reactive fibers to photosensitive igniters. The filament employs aluminum fuel within a printable polyvinylidene fluoride matrix that can be tailored to a desired burning rate through stoichiometry or aluminum fuel configuration such as particle size and modified aluminum composites. The material is printable with fused filament fabrication, enabling access to more complex geometries such as spirals and branches that are inaccessible to traditionally cast reactive materials. However, additively manufacturing the reactive fluoropolymer and propellant together comes attendant with many challenges given the significantly different physical properties, particularly regarding adhesion. To circumvent the challenges posed by multiple printing techniques required for such dissimilar materials, the reactive fluoropolymer was included within a solid propellant carrier matrix as small fibers. The fibers were varied in aspect ratio (AR) and orientation, with aspect ratios greater than one exhibiting a self-alignment behavior in concordance with the prescribed extrusion direction. The effective burning rate of the propellant was improved nearly twofold with 10 wt.% reactive fibers with an AR of 7 and vertical orientation.

The reactive wires and fibers in propellant proved difficult to image in realistic sample designs, given that traditional visible imaging techniques restrict the location and dimensions of the reactive wire due to the necessity of an intrusive window next to the wire, a single-view dynamic X-ray imaging technique was employed to analyze the evolution of the internal burning profile of propellant cast with embedded additively manufacture reactive components. To image complex branching geometries and propellant with multiple reactive components stacked within the same line of sight, the dynamic X-ray imaging technique was expanded to two views. Topographic reconstructions of propellants with multiple reactive fibers showed the evolution of the burning surface enhanced by the geometric effects caused by the faster burning fibers. These dual-view reconstructions provide a method for accurate quantitative analysis of volumetric burning rates that can improve the accessibility and viability of novel propellant grain designs.