Добірка наукової літератури з теми "Periodic Micron Structures"

This article reviews the development in our laboratory of magnetic lattices comprising periodic arrays of magnetic microtraps created by patterned magnetic films to trap periodic arrays of ultracold atoms. Recent achievements include the realisation of multiple Bose-Einstein condensates in a 10 \(\mu\)m-period one-dimensional magnetic lattice; the fabrication of sub-micron-period square and triangular magnetic lattice structures suitable for quantum tunnelling experiments; the trapping of ultracold atoms in a sub-micron-period triangular magnetic lattice; and a proposal to use long-range interacting Rydberg atoms to achieve spin-spin interactions between sites in a large-spacing magnetic lattice.

ZnS nano and micro structures such as nanoribbons, large sheets and tetrapod shaped crystals were fabricated by direct thermal evaporation of ZnS powder without using any catalyst. Formation of the one dimensional structures such as nanoribbons and micron order sheets was attributed to the vapor-solid growth mechanism. The formation of octahedron nucleus with cubic crystal structures was proposed as the growth unit of the wurtzite crystal structured tetrapods. Appearance of the periodic stacking faults or twining planes in between alternate cubic and hexagonal crystal structured zones along the growth direction of the ribbons provided secondary growth sites for the octahedron nucleus and subsequent crystal growth resulted in to the formation of the tetrapod arrays. These nano/micro structures of ZnS exhibited a green emission band at room temperature.

Surface functionalization of plastic parts has been studied and developed for several applications. However, demand for the development of reliable and profitable manufacturing strategies is still high. Here we develop and characterize a new process chain for the versatile and cost-effective production of sub-micron textured plastic parts using laser ablation. The study includes the generation of different sub-micron structures on the surface of a mold using femtosecond laser ablation and vario-thermal micro-injection molding. The manufactured parts and their surfaces are characterized in consideration of polymer replication and wetting behavior. The results of the static contact angle measurements show that replicated Laser-Induced Periodic Surface Structures (LIPSSs) always increase the hydrophobicity of plastic parts. A maximum contact angle increase of 20% was found by optimizing the manufacturing thermal boundary conditions. The wetting behavior is linked to the transition from a Wenzel to Cassie–Baxter state, and is crucial in optimizing the injection molding cycle time.

Several techniques of implant surface structuring have been used in the past to modify the surface of titanium and its alloys. We first investigated the adhesion property of human osteoblasts (MG-63) on femtosecond laser treated Ti-6Al-4V for application in dental implant. Two different kinds of surface structures were generated with varied laser fluence. (1) Laser-induced periodic surface structures (LIPSS) with a period on the sub-micron level. (2) Microscale peaks and troughs surface structures (MPTSS) with superimposed submicron and nanoscale features. According to the cell quantity and adhesion property of MG-63 on polished and structured samples, femtosecond laser treated Ti-6Al-4V with LIPSS may more suitable for applied in dental implant.

Large-scale nonlinear simulations of Jupiter's 5-micron hot spots produce long-lived coherent structures that cause subsidence in local regions, explaining the low cloudiness and the dryness measured by the Galileo probe inside a hot spot. Like observed hot spots, the simulated coherent structures are equatorially confined, have periodic spacing, propagate west relative to the flow, are generally confined to one hemisphere, and have an anticyclonic gyre on their equatorward side. The southern edge of the simulated hot spots develops vertical shear of up to 70 meters per second in the eastward wind, which can explain the results of the Galileo probe Doppler wind experiment.

Multi-layer, metallo-dielectric structures (screens) have long been employed as electromagnetic band filters, either in transmission or in reflection modes. Here we study the radiation energy not transmitted or reflected by these structures (trapped radiation, which is denoted—absorption). The trapped radiation leads to hot surfaces. In these bi-layer screens, the top (front) screen is made of metallic hole-array and the bottom (back) screen is made of metallic disk-array. The gap between them is filled with an array of dielectric spheres. The spheres are embedded in a dielectric host material, which is made of either a heat-insulating (air, polyimide) or heat-conducting (MgO) layer. Electromagnetic intensity trapping of 97% is obtained when a 0.15 micron gap is filled with MgO and Si spheres, which are treated as pure dielectrics (namely, with no added absorption loss). Envisioned applications are anti-fogging surfaces, electromagnetic shields, and energy harvesting structures.

The fabrication of large area nanoscale periodic structures on material surfaces for hydrophobicity engineering has been difficult due to the complex processes. Here we propose a two-step fabrication method for periodic nanostructures by combining laser interference lithography (LIL) and reactive ion etching (RIE). Sub-micron periodic nanotip patterns are fabricated in the photoresist by LIL, and then transferred into the silicon substrate using RIE. By measuring the contact angle (CA) of a water droplet on the substrate surface, the wettability of the surface with nanotip structures of various periods is studied. Our experiments show that the nanotip structures fabricated by the combined LIL and RIE process deliver satisfactory hydrophobic tendencies when the periods fall into the submicron scale. When the period of the structure is small enough, the hydrophilicity of the surface can be altered into hydrophobicity. The hydrophobicity achieved by this method is reusable and sustainable with low cost and no composition alteration comparing to chemical methods. The process developed in this work provides potential applications in biosensingand digital fluidics.

Some recent research in laser-induced surface ripple structures, surface ablation, surface colouration, and their potential industrial applications are discussed in this article. Both wavelength and sub-wavelength periodic surface structures were observed on semiconductors such as InP and GaN/sapphire surfaces after irradiation of femtosecond laser pulses. The orientation of the periodic structures was dependant on the laser beam polarization, and the period was dependent on the incident laser fluence. Such surface periodic structures may find applications in controlling surface hydrophobic and hydrophilic properties. Excimer laser ablation of epoxy compounds from wafer level chip size packages was found to be a feasible method to expose the micron-size Au bumps for solder reflow, which is a critical process in manufacturing portable electronic products. Studies on controlled surface oxidation by laser pulses showed that a range of colours can be achieved on a stainless steel surface. Selective Cr oxidation and iron oxides were detected. The appearance of colour is the result of the light constructive interference of the transparent oxide layer and is determined by the oxide thickness and the refractive index. The potential industrial applications of the techniques are discussed.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 130-147).
A central pillar of real-world engineering is controlled molding of different types of waves (such as optical and acoustic waves). The impact of these wave-molding devices is directly dependent on the level of wave control they enable. Recently, artificially structured metamaterials have emerged, offering unprecedented flexibility in manipulating waves. The design and fabrication of these metamaterials are keys to the next generation of real-world engineering. This thesis aims to integrate computer science, materials science, and physics to design novel metamaterials and functional devices for photonics and nanotechnology, and translate these advances into realworld applications. Parallel finite-difference time-domain (FDTD) and finite element analysis (FEA) programs are developed to investigate a wide range of problems, including optical micromanipulation of biological systems [1, 2], 2-pattern photonic crystals [3], integrated optical circuits on an optical chip [4], photonic quasicrystals with the most premier photonic properties to date [5], plasmonics [6], and structure-property correlation analysis [7], multiple-exposure interference lithography [8], and the world's first searchable database system for nanostructures [9].
by Lin Jia.
Ph.D.

Patterning, the utilisation and manipulation of geometric properties, is important both for the rational design of technological devices and also to the understanding of many natural phenomena. In this thesis I examine the way in which micro and nano patterning can alter optical properties across a large range of wavelength scales and how these novel phenomena can be utilised. Micro patterned electrodes can tune the geometry of radio frequency electric fields to generate dielectrophoretic microfluidic devices. These devices use the dielectrophoretic force to sort, position and characterise the properties of micro and nano particles. I develop a new image processing algorithm that radically improves experimental efficiency allowing for real-time supervisor free dielectrophoretic characterisation of nanoparticles. Metamaterials are composite structures that have repeating units that are much smaller than the wavelength of radiation they are designed to work with. The optical properties of the materials are derived from these units rather than the bulk characteristics of the materials they are composed of. I demonstrate the development of novel THz metamaterial absorber devices. These devices provide a means to design and control the absorption of THz radiation, modulating bandwidth, polarization dependence and frequency in a form that is readily integrable with other standard fabrication processes. Finally by periodically patterning materials on the nanometer scale I demonstrate the development of novel photonic crystal devices and complementary optical components. In these devices the periodicity of the electromagnetic wave is modulated by the periodicity of the structures themselves resulting in band gaps and resonances analogous to the band gaps and defect states found commonly in semi-conductor physics. I demonstrate the theory, fabrication and measurement of these devices using novel broadband supercontinuum sources and propose a future application for biosensing. Further topics covered in the appendix include the development of a spin out technology, a $100 open source atomic force microscope developed while spending time in China. Finally I examine the role of patterning for optimising the performance of nanomechanical cantilever biosensors, and show how geometrical effects on the microscopic scale are crucial to understanding the workings of the vancomycin family of antibiotics, as screened using microcantilevers. Portions of this report are edited extracts from published articles resulting from this work, a full list of which is given in Appendix A.

The main aim of this work was to develop the formation technique of periodic micro-structures by interference lithography in photosensitive polymeric materials, experimentally investigate possibilities and limitations of the method, and to create micro-structures suitable for practical applications. The shape of the micro-structures fabricated by interference lithography depends on the used laser irradiation dose, laser wavelength, phase, polarization, the angle between interfering beams and the number of the interfering beams, and their rigidity - mainly on the used laser irradiation dose. In this work also the possibility to form micro-tube and scaffolds arrays by using interference lithography was demonstrated and the control of the geometrical parameters of micro-lenses fabricated by interference lithography and manipulating the laser irradiation dose was investigated in depth. The possibility to immobilize the newly synthesized aromatic azides molecules in PEG matrix by photo-grafting technique was also demonstrated and the copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) chemical reaction by using azide “MegaStokes dye 673” was realized, in order to show the capability to combine the photo-grafting technique with “click” chemistry. The developed 3D site-specific functionalization method is simple and versatile; it has potential applications in micro-array based proteome analysis, studies of cell-surface interactions, sensing applications, and drug screening.
Disertacijos tikslas buvo sukurti metodą periodinių darinių formavimui interferencinės litografijos būdu, polimerizuojant fotojautrias medžiagas, eksperimentiškai ištirti šio metodo galimybes ir ribojimus bei suformuoti mikrodarinius, tinkamus praktiniams taikymams. Eksperimentų metu buvo pademonstruota, kad interferencinės litografijos metodu formuojamų mikrodarinių forma priklauso nuo: lazerinės apšvitos dozės, bangos ilgio, fazės, kampo tarp interferuojančių pluoštų ir pluoštų skaičiaus, o jų tvirtumas labiausiai priklauso nuo lazerinės apšvitos dozės. Šiame darbe taip pat parodyta, kad naudojant interferencinės litografijos metodą viena lazerine ekspozicija galima formuoti mikrovamzdelių ir mikrolęšių masyvus bei karkasus iš biosuderinamos ir biosuskaidomos PEG-DA-258 medžiagos. Be polimerinių darinių formavimo, šiame darbe pademonstruota ir jų fotomodifikavimo galimybė, naudojant fotoįskiepijimo (angl. photo-grafting) technologiją, o taip pat realizuojant variu katalizuojamos azido alkino ciklizacijos (CuAAC) cheminę reakciją parodyta fotoįskiepijimo technologijos ir „klik“ chemijos apjungimo galimybė. Toks paprastas ir universalus būdas atveria naujas galimybes biojutiklių kūrime ir audinių inžinerijoje, nes molekulių imobilizavimas polimero matricoje vyksta trimatėje erdvėje ir tiksliai norimoje vietoje, o trimatė erdvinė gradientinė kontrolė yra labai svarbi daugybėje biotechnologijos taikymų.

Une approche dynamique discrète (DDM) est proposée dans le contexte de la mécanique des poutres pour calculer les caractéristiques de dispersion des structures périodiques. Cette démarche permet de calculer les caractéristiques de dispersion de milieux périodiques unidimensionnels et bidimensionnels. Il est montré qu’un développement d'ordre supérieur suffisamment élevé des forces et des moments d’éléments structuraux est nécessaire pour décrire avec précision les modes de propagation d’ordre supérieur. Ces résultats montrent dans l’ensemble que les calculs des caractéristiques de dispersion de systèmes structurels périodiques peuvent être abordés avec une bonne précision par la dynamique des éléments discrets. Les comportements non classiques peuvent être capturés non seulement par une expansion d'ordre supérieur mais aussi par des formulations à gradient supérieur. Nous calculons ainsi les paramètres constitutifs macroscopiques jusqu'au deuxième gradient du déplacement en utilisant deux formulations différentes, soit selon une méthode d'homogénéisation dynamique à gradient supérieur (DHGE) prenant en compte les effets de micro-inertie, ou alternativement selon le principe de Hamilton. Nous analysons ensuite la sensibilité des termes constitutifs du second gradient aux paramètres microstructuraux pour des matériaux composites à microstructure périodique de type laminés. En plus, on montre que les modèles du deuxième gradient formulés à partir de l'énergie interne totale en tenant compte des termes de gradient d'ordre supérieur donnent la meilleure description du propagation d’onde à travers ces milieux. On analyse les contributions d'ordre supérieur et de micro-inertie sur le comportement mécanique de structures composites en utilisant une méthode d'homogénéisation dynamique d'ordre supérieur qui intègre les effets de micro-inertie. Nous calculons la réponse effective statique longitudinale à gradient d’ordre supérieur, en quantifiant la différence relative par rapport à la formulation classique de type Cauchy qui repose sur le premier gradient du déplacement. Nous analysons ensuite les propriétés de propagation d’ondes longitudinales en termes de fréquence propre de composites, en tenant compte de la contribution de la micro-inertie. La longueur interne joue un rôle crucial dans les contributions de micro-inertie avec un effet substantiel pour les faibles valeurs de longueur interne, et qui correspond à une large gamme de matériaux utilisés en ingénierie des structures. La méthode d’homogénéisation développée montre un effet de taille important pour les modules élastiques homogénéisés d’ordre supérieur. Par conséquent, nous développons une formulation indépendante de la taille qui est basée sur des termes de correction liée aux moment quadratique. Dans ce contexte, on analyse l’influence des termes de correction sur le comportement statique et dynamique de composites à inclusion
A discrete dynamic approach (DDM) is developed in the context of beam mechanics to calculate the dispersion characteristics of periodic structures. Subsequently, based on this dynamical beam formulation, we calculate the dispersion characteristics of one-dimensional and two-dimensional periodic media. A sufficiently high order development of the forces and moments of the structural elements is necessary to accurately describe the propagation modes of higher order. These results show that the calculations of the dispersion characteristics of structural systems can be approached with good accuracy by the dynamics of the discrete elements. Besides, non-classical behaviors can be captured not only by higher order expansion but also by higher gradient formulations. To that scope, we develop a higher gradient dynamic homogenization method with micro-inertia effects. Using this formulation, we compute the macroscopic constitutive parameters up to the second gradient, using two distinct approaches, namely Hamilton’s principle and a total internal energy formulation. We analyze the sensitivity of the second gradient constitutive terms on the inner material and geometric parameters for the case of composite materials made of a periodic, layered microstructure. Moreover, we show that the formulations based on the total internal energy taking into account higher order gradient terms give the best description of wave propagation through the composite. We analyze the higher order and micro-inertia contributions on the mechanical behavior of composite structures by calculating the effective static and dynamic properties of composite beams using a higher order dynamic homogenization method. We compute the effective longitudinal static response with higher order gradient, by quantifying the relative difference compared to the classical formulation of Cauchy type, which is based on the first gradient of displacement. We then analyze the propagation properties of longitudinal waves in terms of the natural frequency of composite structural elements, taking into account the contribution of micro-inertia. The internal length plays a crucial role in the contributions of micro-inertia, which is particularly significant for low internal length values, therefore for a wide range of materials used in structural engineering. The developed method shows an important size effect for the higher gradients, and to remove these effects correction terms have been incorporated which are related to the quadratic moment of inertia. We analyze in this context the influence of the correction terms on the static and dynamic behavior of composites with a central inclusion

Orientador: Luiz Carlos Kretly
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Neste trabalho, as diferentes propriedades de superfícies seletivas em frequência, FSS - Frequency Selective Surfaces, são analisadas. As FSS são estruturas planares com células periódicas e podem ser classificadas como uma classe de metamateriais. Para tanto, o mecanismo de trabalho dessas estruturas foi extensivamente estudado, e um método próprio, baseado no modelo de circuito equivalente em conjunto com simulações de onda completa foi proposto. A ferramenta desenvolvida é útil para uma análise preliminar rápida de FSS, a qual foi utilizada para criar uma base de dados de elementos conhecidos na literatura. Diferente dos modelos de análise clássicos, a modelagem analítica proposta, que é uma das principais contribuições do trabalho, usa um simples algoritmo para aproximar a resposta de superfícies seletivas em frequência com geometrias arbitrárias, para incidências normal e oblíqua e para substratos com quaisquer espessuras. Nesse sentido, após a simulação eletromagnética da estrutura, é possível computar a resposta de uma FSS com diferentes parâmetros sem o consumo de tempo das simulações de onda completa. O modelo usa as características peculiares de superfícies de alta impedância, HIS - High Impedance Surface, que dentro de determina faixa comporta-se como condutor magnético perfeito, PMC - Perfect Magnetic Conductor, enquanto no restante da banda tem comportamento de um condutor elétrico perfeito, PEC - Perfect Electric Conductor, para sintetizar absorvedores finos e planares de micro-ondas. As estruturas, compostas de superfície seletiva em frequência resistivas sobre um substrato dielétrico aterrado, são projetadas visando aplicação em diferentes faixas de frequência de absorção e diferentes larguras de banda. Na faixa de 5,5 GHz, objetivou-se satisfazer as especificações dos sistemas WIMAX, WLAN, com os padrões IEEE 802.11a, bem como sistemas de radar, enquanto sinais de outras faixas podem trafegar com atenuação mínima ou nula. Para a faixa mais elevada, projetou-se uma estrutura que oferece absorção sobre a faixa de frequências de 10 GHz a 18 GHz, que pode ser empregada visando aplicações na banda-X e banda-Ku. O método de modelagem para a FSS e para os absorvedores propostos foi validado fisicamente através de montagens experimentais e instrumentação, especialmente desenvolvidas para estas estruturas. Os protótipos dos absorvedores fabricados são extremamente finos e foram medidos por meio de setups de medida em campo aberto e em câmara anecóica. As estruturas projetadas mostraram excelente desempenho para as faixas medidas, mantendo refletividade tipicamente abaixo de -10 dB ao longo de toda a banda. A metodologia desenvolvida nesta pesquisa pode ser ampliada para diferentes faixas de frequências, larguras de banda e aplicações
Abstract: In this work, the different properties of frequency selective surfaces - FSS are analyzed. Frequency selective surfaces are planar structures with periodic cells and can be classified as a kind of metamaterials. To this end, the working mechanism of these structures has been extensively studied, and a proper method based on the equivalent circuit model in conjunction with full-wave simulations was proposed. The developed tool is useful for a fast preliminary analysis of FSS, which was used to create a database of known elements presented in the literature. Unlike of classical analysis model, the proposed analytical modeling, which is one of the main thesis contributions, uses a simple algorithm for approximate the response of frequency selective surfaces with arbitrary shape, for normal and oblique incidence and for substrates with all thicknesses. In this sense, after the electromagnetic simulation of the structure, it is possible to compute the response of an FSS with different parameters without the time consuming full-wave simulations. The model uses the unique characteristics of High-Impedance Surfaces - HIS, which for certain frequency range, behaves as Perfect Magnetic Conductor - PMC, while outside this band behaves as a Perfect Electric Conductor - PEC, for synthesizing thin planar microwave absorbers. The structures, comprising resistive frequency selective surfaces over a grounded dielectric substrate, are designed aiming different absorption frequency bands and different bandwidths. In the 5.5 GHz frequency range, the aim was to satisfy the specifications of WiMAX, WLAN systems, in view of the IEEE 802.11a standards, as well as radar systems, while signals from other bands can travel across with zero or minimal attenuation. To the highest range, the designed structure provides absorption over 10 GHz to 18 GHz frequency range, and can be applied to the X- and Ku- band. The modeling method for the FSS and the proposed absorbers was physically validated through experimental setups and instrumentation, especially developed for these structures. The prototype of the fabricated absorbers are extremely thin and were characterized by using free space and anechoic chamber measurement setups. The designed structures showed excellent performance for measurements ranges, with reflectivity typically below -10 dB over the entire band. The methodology developed in this research can be extended to different frequency bands, bandwidth and applications
Doutorado
Eletrônica, Microeletrônica e Optoeletrônica
Doutor em Engenharia Elétrica

Disertacijos tikslas buvo sukurti metodą periodinių darinių formavimui interferencinės litografijos būdu, polimerizuojant fotojautrias medžiagas, eksperimentiškai ištirti šio metodo galimybes ir ribojimus bei suformuoti mikrodarinius, tinkamus praktiniams taikymams. Eksperimentų metu buvo pademonstruota, kad interferencinės litografijos metodu formuojamų mikrodarinių forma priklauso nuo: lazerinės apšvitos dozės, bangos ilgio, fazės, kampo tarp interferuojančių pluoštų ir pluoštų skaičiaus, o jų tvirtumas labiausiai priklauso nuo lazerinės apšvitos dozės. Šiame darbe taip pat parodyta, kad naudojant interferencinės litografijos metodą viena lazerine ekspozicija galima formuoti mikrovamzdelių ir mikrolęšių masyvus bei karkasus iš biosuderinamos ir biosuskaidomos PEG-DA-258 medžiagos. Be polimerinių darinių formavimo, šiame darbe pademonstruota ir jų fotomodifikavimo galimybė, naudojant fotoįskiepijimo (angl. photo-grafting) technologiją, o taip pat realizuojant variu katalizuojamos azido alkino ciklizacijos (CuAAC) cheminę reakciją parodyta fotoįskiepijimo technologijos ir „klik“ chemijos apjungimo galimybė. Toks paprastas ir universalus būdas atveria naujas galimybes biojutiklių kūrime ir audinių inžinerijoje, nes molekulių imobilizavimas polimero matricoje vyksta trimatėje erdvėje ir tiksliai norimoje vietoje, o trimatė erdvinė gradientinė kontrolė yra labai svarbi daugybėje biotechnologijos taikymų.
The main aim of this work was to develop the formation technique of periodic micro-structures by interference lithography in photosensitive polymeric materials, experimentally investigate possibilities and limitations of the method, and to create micro-structures suitable for practical applications. The shape of the micro-structures fabricated by interference lithography depends on the used laser irradiation dose, laser wavelength, phase, polarization, the angle between interfering beams and the number of the interfering beams, and their rigidity - mainly on the used laser irradiation dose. In this work also the possibility to form micro-tube and scaffolds arrays by using interference lithography was demonstrated and the control of the geometrical parameters of micro-lenses fabricated by interference lithography and manipulating the laser irradiation dose was investigated in depth. The possibility to immobilize the newly synthesized aromatic azides molecules in PEG matrix by photo-grafting technique was also demonstrated and the copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) chemical reaction by using azide “MegaStokes dye 673” was realized, in order to show the capability to combine the photo-grafting technique with “click” chemistry. The developed 3D site-specific functionalization method is simple and versatile; it has potential applications in micro-array based proteome analysis, studies of cell-surface interactions, sensing applications, and drug screening.

A rapid, mask-less deposition technique for writing metal tracks has been developed. The technique was based on laser-induced chemical vapour deposition. The novelty in the technique was the usage of pulsed ultrafast lasers instead of continuous wave lasers in pyrolytic dissociation of the chemical precursor. The motivation of the study was that (1) ultrafast laser pulses have smaller heat affected zones thus the deposition resolution would be higher, (2) the ultrashort pulses are absorbed in most materials (including those transparent to the continuous wave light at the same wavelength) thus the deposition would be compatible with a large range of materials, and (3) the development of higher frequency repetition rate ultrafast lasers would enable higher deposition rates. A deposition system was set-up for the study to investigate the ultrafast laser deposition of tungsten from tungsten hexacarbonyl chemical vapour precursors. A 405 nm laser diode was used for continuous wave deposition experiments that were optimized to achieve the lowest track resistivity. These results were used for comparison with the ultrafast laser track deposition. The usage of the 405 nm laser diode was itself novel and beneficial due to the low capital and running cost, high wall plug efficiency, high device lifetime, and shallower optical penetration depth in silicon substrates compared to green argon ion lasers which were commonly used by other investigators. The lowest as-deposited track resistivity achieved in the continuous wave laser experiments on silicon dioxide coated silicon was 93±27 µΩ cm (16.6 times bulk tungsten resistivity). This deposition was done with a laser output power of 350 mW, scan speed of 10 µm/s, deposition pressure of 0.5 mBar, substrate temperature of 100 °C and laser spot size of approximately 7 µm. The laser power, scan speed, deposition pressure and substrate temperature were all optimized in this study. By annealing the deposited track with hydrogen at 650 °C for 30 mins, removal of the deposition outside the laser spot was achieved and the overall track resistivity dropped to 66±7 µΩ cm (11.7 times bulk tungsten resistivity). For ultrafast laser deposition of tungsten, spot dwell experiments showed that a thin film of tungsten was first deposited followed by quasi-periodic structures perpendicular to the linear polarization of the laser beam. The wavelength of the periodic structures was approximately half the laser wavelength (λ/2) and was thought to be formed due to interference between the incident laser and scattered surface waves similar to that in laser-induced surface periodic structures. Deposition of the quasi-periodic structures was possible on stainless steel, silicon dioxide coated silicon wafers, borosilicate glass and polyimide films. The thin-films were deposited when the laser was scanned at higher laser speeds such that the number of pulses per spot was lower (η≤11,000) and using a larger focal spot diameter of 33 µm. The lowest track resistivity for the thin-film tracks on silicon dioxide coated silicon wafers was 37±4 µΩ cm (6.7 times bulk tungsten resistivity). This value was achieved without post-deposition annealing and was lower than the annealed track deposited using the continuous wave laser. The ultrafast tungsten thin-film direct write technique was tested for writing metal contacts to single layer graphene on silicon dioxide coated silicon substrates. Without the precursor, the exposure of the graphene to the laser at the deposition parameters damaged the graphene without removing it. This was evidenced by the increase in the Raman D peak of the exposed graphene compared to pristine. The damage threshold was estimated to be 53±7 mJ/cm2 for a scanning speed of 500 µm/s. The deposition threshold of thin-film tungsten on graphene at that speed was lower at 38±8 mJ/cm2. However, no graphene was found when the deposited thin-film tungsten was dissolved in 30 wt% H2O2 that was tested to have no effect on the graphene for the dissolution time of one hour. The graphene likely reacted with the deposited tungsten to form tungsten carbide which was reported to dissolve in H2O2. Tungsten carbide was also found on the tungsten tracks deposited on reduced graphene oxide samples. The contact resistance between tungsten and graphene was measured by both transfer length and four-point probe method with an average value of 4.3±0.4 kΩ µm. This value was higher than reported values using noble metals such as palladium (2.8±0.4 kΩ µm), but lower than reported values using other metals that creates carbides such as nickel (9.3±1.0 kΩ µm). This study opened many potential paths for future work. The main issue to address in the tungsten ultrafast deposition was the deposition outside the laser spot. This prevented uniform deposition in successive tracks close to one another. The ultrafast deposition technique also needs verification using other precursors to understand the precursor requirements for this process. An interesting future study would be a combination with a sulphur source for the direct write of tungsten disulphide, a transition metal dichalcogenide that has a two-dimensional structure similar to graphene. This material has a bandgap and is sought after for applications in high-end electronics, spintronics, optoelectronics, energy harvesting, flexible electronics, DNA sequencing and personalized medicine. Initial tests using sulphur micro-flakes on silicon and stainless-steel substrates exposed to the tungsten precursor and ultrafast laser pulses produced multilayer tungsten disulphide as verified in Raman measurements.

Les structures maçonnées sont largement connues en génie civil comme constituant d’une partie des bâtiments, mais également en tant que garnissages réfractaires dans des structures utilisées à hautes températures, par exemple en sidérurgie. Malheureusement, les outils actuels ne sont pas suffisamment puissants pour prédire le comportement de ces structures avec l’apparition de fissures et pour tenir compte du comportement non linéaire d’un des deux constituants (le mortier par exemple). Ce travail de thèse contribue à la modélisation multi-échelles des maçonneries classiques et des garnissages réfractaires avec un faible coût numérique grâce à la technique d’homogénéisation périodique. Les techniques de modélisation et de simulation du comportement des maçonneries sont présentées et développées. L’influence des lois d’interface entre briques et mortier, des paramètres géométriques et matériels, ainsi que de la densité des fissures sur le comportement effectif des maçonneries est étudié. Trois approches (une extension analytique de Cecchi et Tralli, une approche numérique et un modèle micromécanique) sont proposées pour la détermination du comportement effectif d’une cellule périodique dans le cas de maçonneries avec mortier viscoélastique microfissuré et briques saines élastiques ou rigides. Les résultats des calculs sur deux exemples de maçonneries (1D et 2D) ont confirmé que l’approche multi-échelle est une solution appropriée avec une grande capacité à exprimer le comportement des maçonneries viscoélastiques microfissurées. Ce travail, limité au cas sans propagation de fissures, peut être étendu aux mortiers à comportement viscoplastique
Masonry structures are widely used in civil engineering as part of buildings or in refractory linings of structures working at high temperatures, like in steel industry. Unfortunately, the present tools are not powerful enough to predict the behavior of these structures at their micro-cracked state and/or if one of their constituents behaves nonlinearly (e.g. the mortar). This research contributes to the multi-level modeling of classical masonries and refractory linings with a low numerical cost using basically the periodic homogenization technique. Modeling and simulation techniques of masonry behavior are presented and developped. The influence of interface law between bricks and mortar, of geometrical and material parameters, and of crack density on the effective masonry behavior is studied. Three approaches (analytical extension of Cecchi and Tralli, numerical approach and micromechanical modeling) were proposed to determine the effective behavior of a periodic masonry cell with micro-cracked viscoelastic mortar and safe elastic or rigid bricks. The results obtained on two examples of masonry (1D and 2D) confirmed that the multi-scale approach is a suitable solution with a great ability to model the effective behavior of microcracked viscoelastic masonry. This work, actually limited to the case without crack propagation, could be extended to mortars with viscoplastic behavior

Over the past few decades, the study of field distribution at the geometrical focus of a lens (PSF) has gained a huge research interest in field ranging from Nanolithography to microscopy. The central theme of this thesis is to study the intricate details of the field distribution through theoretical modelling, computational studies and experimentation. Specifically, spatial filtering techniques have been proposed to understand and manipulate the field distribution for demanding applications. Based on the findings during the theoretical modelling and computational studies we have proposed light sheet based optical lithography technique. Optical lithography (Photolithography) has emerged as an efficient tool for the fabrication of micro/Nanostructures. It uses photon energy to create patterns on the substrate coated with a photosensitive material. The photochemical reactions which are necessary for the fabrication are spatially confined by the 3D extent of the field distribution. Hence the knowledge of field distribution plays a very crucial role in photolithography. State of the art techniques in optical lithography such as, two photon direct laser writing lithography, interference-based lithography techniques and STED Nano-lithography have made optical lithography a highly sought-after technique for the fabrication of micro/Nanostructures. Specifically, two photon direct lithography is used for making complex 3D structures. Interference based lithography techniques are used for fabricating 1D, 2D and 3D periodic Nanostructures whereas, STED Nano-lithography is capable of fabricating diffraction unlimited structures. The first chapter provides an overview of all the keywords and concepts used in photolithography. A brief summary of the emergence of the field is provided along with the development of different optical lithography techniques. The discovery of photopolymerization process and invention of various photoresist systems has helped in the development of photolithography. These techniques have made physics, chemistry and biology accessible to Nano-scale level. An introduction to photoresist systems and them brief classification is given in this chapter. In addition, we have also provided a brief description to recent techniques in photolithography that is widely used for micro/nanofabrication. Understanding these techniques helps us in identifying the novelty of the proposed lithography technique. A brief introduction is given to understand the field distribution/ point spread function (PSF) that provides the foundation for the entire thesis. In the second chapter, we describe the vectoral model for theoretically understanding the PSF for a spherical lens geometry. This is predominantly since the existing lithography techniques relay on spherical lens geometry. In view of demanding applications, the illumination PSF is tailored by employing spatial filtering techniques. We intend to employ spatial filter in order to add new features to lithography and expand its reach. For example, introduction of spatial filter at the back aperture of an objective lens produce a Bessel like beam which is generally used for applications that requires greater depth of focus. Bessel beams have self-reconstructing property which helps to achieve a greater depth of focus in scattering mediums. The extent of the PSF along the axial direction (z-direction) is 2-3 times greater when compared to the lateral extent. Hence the resolution along z-direction is 2-3 times worse when compared to its lateral counterpart. 4 geometry is generally employed to improve the axial resolution in spherical lens system. But this technique suffers from side-lobes that can cause artefacts. In order to reduce side lobes, we employed spatial filter in a 4_ geometry. A detailed description of these techniques is given in chapter 2. These techniques may add new features to Nano-lithography techniques and bring new applications in Nano-biology and Nanophysics. Chapters 3, 4 and 5 of the theses are dedicated to light-sheet based lithography for the fabrication of micro/Nanostructures. We begin by studying the field distribution at the geometrical focus of a cylindrical lens system. Unlike a spherical lens system, cylindrical lens system has a one-dimensional focusing property that results in a sheet of light. light-sheets are known for their selective plane illumination capabilities. They are widely used in bioimaging and optical microscopy. The intricate details about the field distribution are studied using the vectoral theory for cylindrical lens system. We have conducted experiments to validate the vectoral theory for cylindrical lens. _2 test revealed a good _t between experiment and theoretically obtained values. Like spatial filtering techniques in spherical lens geometry, we have carried out spatial filtering in cylindrical lens geometry to add new functionalists/ features in lithography. It is shown that the introduction of spatial filter at the back aperture of the cylindrical lens has resulted in the generation of multiple light-sheets. Spatial filter structures the incident wave front that is focused by the cylindrical lens thereby resulting in a distinct field distribution at and near the focal plane. The theory behind the generation of multiple light-sheets is discussed in chapter 3. We have demonstrated the generation of multiple light-sheets through computational simulations and experiment. Multiple light-sheets have the capability of illuminating multiple planes of the specimen simultaneously. The experimental results are discussed in chapter 3. Chapter 4 describes the fabrication of periodic micron structures using multiple light sheets. We have used a photoresist mixture which is sensitive to visible light. UV- Vis absorption spectroscopy was used to determine the sensitivity of the photoresist mixture. The photochemistry was studied using a 532 nm continuous laser. We could control the periodicity and the feature size by changing the spatial filter parameters. This technique is hoped to be a single shot fabrication technique for generating high aspect ratio periodic micron structures over a large area. In chapter 5, we have proposed and experimentally demonstrated the generation of periodic Nanostructures using counter propagating coherent light-sheets. The technique involves two opposing cylindrical lenses. When these lenses illuminate the common geometrical focus with a coherent beam of light a constructive interference takes place between two counter propagating light-sheets. The resulting interference structures can be captured on a substrate coated with the photoresist. Selective plane illumination nature of light-sheets is exploited to carry out patterning in the desired plane of a positive photoresist. A mathematical equation is derived that describes the field distribution at and around the common geometrical focus of two opposing cylindrical lens system. Before carrying out the fabrication, we have studied the field distribution in depth through computational simulations. Th periodicity is found to be half the wavelength of illumination light, whereas feature size is found to be approximately one fourth of the wavelength. This clearly indicates that sub-diffraction limited features can be generated using the proposed technique. The remaining part of this chapter describes the fabrication processes for the commercially available photoresist, S1813. This technique can be used for the fabrication of Nano-channels. Interesting applications are in bio-molecular research and protein analysis. Nano-channels are widely used in the detection and analysis of biomolecules such as DNA, proteins and ions. The ability to carve 2D periodic Nanostructures has a great potential for future technology development. Multiple beam interference lithography is most widely used technique for the fabrication of 2D and 3D periodic Nanostructures. In this technique, parameters (like amplitude and polarization angle) of the individual beam and the angle between the beams control the interference pattern. Choosing the right set of parameters for the individual beam is highly challenging. Phase mask lithography can produce desired beams from a single source. But these experiments are highly complex and requires expertise. Processes involved in the fabrication of phase mask are exigent. Chapter 6 describes the fabrication of 2D periodic Nanostructures. We have integrated spatial filtering technique with 2_ illumination to generate of 2D periodic Nanostructures. Theoretical and computational studies show that multiple light-sheets can be generated using an amplitude binary filter. Interference of counter propagating multiple light sheets result in a 2D periodic intensity distribution at the common geometrical focus which can be used for the fabrication of 2D periodic Nanostructures. This technique can be a stepping stone towards the fabrication of nanoelectromechanical systems (NEMS), fabrication of metamaterials and photonic crystals. Finally, we conclude the thesis with a brief description on the contribution of the thesis and the future scope of the research work.

This book explores the formation, development, and characteristics of modern China's finance, focusing especially on Guangdong province as a case study to illustrate both the macro-level trends and the micro-level reality. The chronological range of this book is mainly from the late Qing period to the early Republican Era ending in 1937, when the full-scale Second Sino-Japanese War broke out. After the concept of modern finance was introduced to China for the first time in the late Qing period, the efforts to build modern finance continued in the Republican Era both nationally and locally. But this process was interrupted by the outbreak of the war against Japan in 1937 and, having been derailed, did not subsequently recover due to the subsequent civil war between the Kuomintang and the Chinese Communist Party. This interrupted process of financial modernization was resumed with Reform and Opening-up, launched in 1978. Therefore, in order to illustrate the structural transformation and persistent characteristics of China’s fiscal system, this book also includes discussions of the early Qing period and current Chinese finance.

This chapter reconstructs how and why complex tenses appeared in Hungarian grammar in the late Proto-Hungarian period, and how and why they disappeared 1000 years later. It claims that the evolution of complex tenses started with a micro-change: the reanalysis of the feature content of a verbal suffix. This step initiated further processes of reanalysis, analogical extension, and abstraction, as a consequence of which the tense system inherited from Uralic, distinguishing only past and nonpast, developed into a complex system marking both tense and viewpoint aspect. The chapter argues that both the appearance of complex tenses, and their disappearance, i.e., the replacement of morphological viewpoint aspect marking by situation aspect marking via verbal particles, was triggered by language contact. In both cases, a translinguistic reanalysis took place: Hungarian speakers assigned to the Hungarian construction the structural–functional properties of the construction of the contact language.

The turn of the 20th and 21st centuries has been a very dynamic period of change in Poland and around the world; also a period of change in thinking about the economy and agriculture. The present work is a study of the decline, divestments and development of agriculture in the areas of fragmented farming structure. The reflections presented herein, upon the processes of the remodelling of agrarian structures, of divestments in farming, and disagrarisation, are mostly anchored in the achievements of the theory of spatial economy (land management), and the microeconomic theories of choice, including the theory of an agricultural holding (farm) and land rent theories. The work focuses on the economic issues of remodelling the agrarian structure, but due to the nature of the issues discussed herein, specifically in relation to family-owned farms, the social and environmental aspects also needed to be taken into account – in response to the need for a heterogeneous approach, which is increasingly stressed in economic sciences today. The main objective of the research was to diagnose and assess the scale and scope of the mechanisms and processes that inform the decline and growth of agricultural holdings in the areas with fragmented farming structure. The study covered the area comprising four regions (provinces) of south-eastern Poland, which – according to the FADN nomenclature – form the macro region of Małopolska and Pogórze. The study of subject literature has been enriched with an analysis of available statistics; data from the Farm Accountancy Data Network (FADN); information obtained from the Department of Programming and Reporting at the Agency for Restructuring and Modernisation of Agriculture; and author’s own research conducted among farm owners. The information thus obtained made it possible to: • Determine the theoretical premises for the spatial diversity of agriculture, and the role of small farms in the shaping of agrarian structure. • Adapt the concept of “divestment” for the description and analysis of the phenomena occurring in agriculture. • Indicate the role and importance of the processes of divestment and disagrarisation in the restructuring of agriculture. • Assess the natural, social and economic determinants of the process of restructuring agriculture in areas with fragmented farming structure. • Assess selected aspects of economic efficiency of agriculture in areas with fragmented farming structure, with the focus on small and micro farms. • Carry out an ex ante evaluation of the impact of agricultural policy instruments on the process of restructuring of agriculture in the macro region of Małopolska and Pogórze. • Identify the indicators of decline and fall, and barriers to the liquidation of farms. • Assess the relationship between the level of socio-economic development, the structure of farming, and the quality of agricultural production space in a given territorial unit, versus the intensity of the economic and production disagrarisation processes in agricultural holdings. • Propose targeted solutions conducive to the improvement of the farming structure in areas with a high framentation of agriculture. Observation of the processes occurring in agriculture, and the scientific theories created on the basis thereof, have shown that even the smallest farms have a chance to continue in existence, provided that we are able to positively verify their adaptation to the changing conditions in the environment. Carrying out farming activity is a prerequisite for implementing the economic, social and environmental functions associated with family farms. At the same time, based on the analyses performed, we need to assume that the advanced processes of the production and economic disagrarisation of agricultural holdings are to a greater extent determined by the anatomical features of agriculture, and by the natural conditions, than by the level of socio-economic development of the given territorial unit. In the current economic climate, the remodelling of the agrarian structure is only possible with the active participation of the institutions responsible for the creation of economic growth and agricultural policy development. It is extremely important from the point of view of environmental protection, and the viability of rural areas, to support small farms engaged in agricultural activities, and to introduce such instruments that will enable the replacement of an economic collapse with divestments, carried out in a planned manner, and allowing for thus released agricultural resources to find alternative application in units with a higher development potential. The area of theoretical research requiring further exploration includes the issues such as transactional costs of the liquidation of agricultural holdings, and the assessment of the economic effectiveness of conducting divestments.

Providing an invaluable introductory resource for students investigating the war in Afghanistan, this book highlights the evolution of the conflict through the documents that helped to shape it. This carefully curated primary source collection includes more than 80 documents from the national and international participants in nearly four decades of conflict that led to the Afghanistan War. Readers will gain an understanding of the macro and micro costs of the war on the participants and the political, social, economic, and military factors that have allowed the fighting to persist. Authored by a former member of the Afghanistan Study Team at the U.S. Army's Combat Studies Institute, readers will gain special insight into the military dynamics of the war in Afghanistan and how the war has changed those who have fought in it. The book is divided into four chapters that cover the primary phases of the war in Afghanistan: The Soviet Invasion and Civil War, 1979–2001; Operation ENDURING FREEDOM and Reconstruction Begins, 2001–2003; The Taliban Return, 2003–2009; and The Surge, Drawdown, and an Uncertain Future, 2009–2017. This structure enables readers to clearly understand how the war evolved and the most significant developments that shaped each period.

Bones are multifunctional passive organs of movement that supports soft tissue and directly attached muscles. They also protect internal organs and are a reserve of calcium, phosphorus and magnesium. Each bone is covered with periosteum, and the adjacent bone surfaces are covered by articular cartilage. Histologically, the bone is an organ composed of many different tissues. The main component is bone tissue (cortical and spongy) composed of a set of bone cells and intercellular substance (mineral and organic), it also contains fat, hematopoietic (bone marrow) and cartilaginous tissue. Bones are a tissue that even in adult life retains the ability to change shape and structure depending on changes in their mechanical and hormonal environment, as well as self-renewal and repair capabilities. This process is called bone turnover. The basic processes of bone turnover are: • bone modeling (incessantly changes in bone shape during individual growth) following resorption and tissue formation at various locations (e.g. bone marrow formation) to increase mass and skeletal morphology. This process occurs in the bones of growing individuals and stops after reaching puberty • bone remodeling (processes involve in maintaining bone tissue by resorbing and replacing old bone tissue with new tissue in the same place, e.g. repairing micro fractures). It is a process involving the removal and internal remodeling of existing bone and is responsible for maintaining tissue mass and architecture of mature bones. Bone turnover is regulated by two types of transformation: • osteoclastogenesis, i.e. formation of cells responsible for bone resorption • osteoblastogenesis, i.e. formation of cells responsible for bone formation (bone matrix synthesis and mineralization) Bone maturity can be defined as the completion of basic structural development and mineralization leading to maximum mass and optimal mechanical strength. The highest rate of increase in pig bone mass is observed in the first twelve weeks after birth. This period of growth is considered crucial for optimizing the growth of the skeleton of pigs, because the degree of bone mineralization in later life stages (adulthood) depends largely on the amount of bone minerals accumulated in the early stages of their growth. The development of the technique allows to determine the condition of the skeletal system (or individual bones) in living animals by methods used in human medicine, or after their slaughter. For in vivo determination of bone properties, Abstract 10 double energy X-ray absorptiometry or computed tomography scanning techniques are used. Both methods allow the quantification of mineral content and bone mineral density. The most important property from a practical point of view is the bone’s bending strength, which is directly determined by the maximum bending force. The most important factors affecting bone strength are: • age (growth period), • gender and the associated hormonal balance, • genotype and modification of genes responsible for bone growth • chemical composition of the body (protein and fat content, and the proportion between these components), • physical activity and related bone load, • nutritional factors: – protein intake influencing synthesis of organic matrix of bone, – content of minerals in the feed (CA, P, Zn, Ca/P, Mg, Mn, Na, Cl, K, Cu ratio) influencing synthesis of the inorganic matrix of bone, – mineral/protein ratio in the diet (Ca/protein, P/protein, Zn/protein) – feed energy concentration, – energy source (content of saturated fatty acids - SFA, content of polyun saturated fatty acids - PUFA, in particular ALA, EPA, DPA, DHA), – feed additives, in particular: enzymes (e.g. phytase releasing of minerals bounded in phytin complexes), probiotics and prebiotics (e.g. inulin improving the function of the digestive tract by increasing absorption of nutrients), – vitamin content that regulate metabolism and biochemical changes occurring in bone tissue (e.g. vitamin D3, B6, C and K). This study was based on the results of research experiments from available literature, and studies on growing pigs carried out at the Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences. The tests were performed in total on 300 pigs of Duroc, Pietrain, Puławska breeds, line 990 and hybrids (Great White × Duroc, Great White × Landrace), PIC pigs, slaughtered at different body weight during the growth period from 15 to 130 kg. Bones for biomechanical tests were collected after slaughter from each pig. Their length, mass and volume were determined. Based on these measurements, the specific weight (density, g/cm3) was calculated. Then each bone was cut in the middle of the shaft and the outer and inner diameters were measured both horizontally and vertically. Based on these measurements, the following indicators were calculated: • cortical thickness, • cortical surface, • cortical index. Abstract 11 Bone strength was tested by a three-point bending test. The obtained data enabled the determination of: • bending force (the magnitude of the maximum force at which disintegration and disruption of bone structure occurs), • strength (the amount of maximum force needed to break/crack of bone), • stiffness (quotient of the force acting on the bone and the amount of displacement occurring under the influence of this force). Investigation of changes in physical and biomechanical features of bones during growth was performed on pigs of the synthetic 990 line growing from 15 to 130 kg body weight. The animals were slaughtered successively at a body weight of 15, 30, 40, 50, 70, 90, 110 and 130 kg. After slaughter, the following bones were separated from the right half-carcass: humerus, 3rd and 4th metatarsal bone, femur, tibia and fibula as well as 3rd and 4th metatarsal bone. The features of bones were determined using methods described in the methodology. Describing bone growth with the Gompertz equation, it was found that the earliest slowdown of bone growth curve was observed for metacarpal and metatarsal bones. This means that these bones matured the most quickly. The established data also indicate that the rib is the slowest maturing bone. The femur, humerus, tibia and fibula were between the values of these features for the metatarsal, metacarpal and rib bones. The rate of increase in bone mass and length differed significantly between the examined bones, but in all cases it was lower (coefficient b <1) than the growth rate of the whole body of the animal. The fastest growth rate was estimated for the rib mass (coefficient b = 0.93). Among the long bones, the humerus (coefficient b = 0.81) was characterized by the fastest rate of weight gain, however femur the smallest (coefficient b = 0.71). The lowest rate of bone mass increase was observed in the foot bones, with the metacarpal bones having a slightly higher value of coefficient b than the metatarsal bones (0.67 vs 0.62). The third bone had a lower growth rate than the fourth bone, regardless of whether they were metatarsal or metacarpal. The value of the bending force increased as the animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. The rate of change in the value of this indicator increased at a similar rate as the body weight changes of the animals in the case of the fibula and the fourth metacarpal bone (b value = 0.98), and more slowly in the case of the metatarsal bone, the third metacarpal bone, and the tibia bone (values of the b ratio 0.81–0.85), and the slowest femur, humerus and rib (value of b = 0.60–0.66). Bone stiffness increased as animals grew. Regardless of the growth point tested, the highest values were observed for the humerus, tibia and femur, smaller for the metatarsal and metacarpal bone, and the lowest for the fibula and rib. Abstract 12 The rate of change in the value of this indicator changed at a faster rate than the increase in weight of pigs in the case of metacarpal and metatarsal bones (coefficient b = 1.01–1.22), slightly slower in the case of fibula (coefficient b = 0.92), definitely slower in the case of the tibia (b = 0.73), ribs (b = 0.66), femur (b = 0.59) and humerus (b = 0.50). Bone strength increased as animals grew. Regardless of the growth point tested, bone strength was as follows femur > tibia > humerus > 4 metacarpal> 3 metacarpal> 3 metatarsal > 4 metatarsal > rib> fibula. The rate of increase in strength of all examined bones was greater than the rate of weight gain of pigs (value of the coefficient b = 2.04–3.26). As the animals grew, the bone density increased. However, the growth rate of this indicator for the majority of bones was slower than the rate of weight gain (the value of the coefficient b ranged from 0.37 – humerus to 0.84 – fibula). The exception was the rib, whose density increased at a similar pace increasing the body weight of animals (value of the coefficient b = 0.97). The study on the influence of the breed and the feeding intensity on bone characteristics (physical and biomechanical) was performed on pigs of the breeds Duroc, Pietrain, and synthetic 990 during a growth period of 15 to 70 kg body weight. Animals were fed ad libitum or dosed system. After slaughter at a body weight of 70 kg, three bones were taken from the right half-carcass: femur, three metatarsal, and three metacarpal and subjected to the determinations described in the methodology. The weight of bones of animals fed aa libitum was significantly lower than in pigs fed restrictively All bones of Duroc breed were significantly heavier and longer than Pietrain and 990 pig bones. The average values of bending force for the examined bones took the following order: III metatarsal bone (63.5 kg) <III metacarpal bone (77.9 kg) <femur (271.5 kg). The feeding system and breed of pigs had no significant effect on the value of this indicator. The average values of the bones strength took the following order: III metatarsal bone (92.6 kg) <III metacarpal (107.2 kg) <femur (353.1 kg). Feeding intensity and breed of animals had no significant effect on the value of this feature of the bones tested. The average bone density took the following order: femur (1.23 g/cm3) <III metatarsal bone (1.26 g/cm3) <III metacarpal bone (1.34 g / cm3). The density of bones of animals fed aa libitum was higher (P<0.01) than in animals fed with a dosing system. The density of examined bones within the breeds took the following order: Pietrain race> line 990> Duroc race. The differences between the “extreme” breeds were: 7.2% (III metatarsal bone), 8.3% (III metacarpal bone), 8.4% (femur). Abstract 13 The average bone stiffness took the following order: III metatarsal bone (35.1 kg/mm) <III metacarpus (41.5 kg/mm) <femur (60.5 kg/mm). This indicator did not differ between the groups of pigs fed at different intensity, except for the metacarpal bone, which was more stiffer in pigs fed aa libitum (P<0.05). The femur of animals fed ad libitum showed a tendency (P<0.09) to be more stiffer and a force of 4.5 kg required for its displacement by 1 mm. Breed differences in stiffness were found for the femur (P <0.05) and III metacarpal bone (P <0.05). For femur, the highest value of this indicator was found in Pietrain pigs (64.5 kg/mm), lower in pigs of 990 line (61.6 kg/mm) and the lowest in Duroc pigs (55.3 kg/mm). In turn, the 3rd metacarpal bone of Duroc and Pietrain pigs had similar stiffness (39.0 and 40.0 kg/mm respectively) and was smaller than that of line 990 pigs (45.4 kg/mm). The thickness of the cortical bone layer took the following order: III metatarsal bone (2.25 mm) <III metacarpal bone (2.41 mm) <femur (5.12 mm). The feeding system did not affect this indicator. Breed differences (P <0.05) for this trait were found only for the femur bone: Duroc (5.42 mm)> line 990 (5.13 mm)> Pietrain (4.81 mm). The cross sectional area of the examined bones was arranged in the following order: III metatarsal bone (84 mm2) <III metacarpal bone (90 mm2) <femur (286 mm2). The feeding system had no effect on the value of this bone trait, with the exception of the femur, which in animals fed the dosing system was 4.7% higher (P<0.05) than in pigs fed ad libitum. Breed differences (P<0.01) in the coross sectional area were found only in femur and III metatarsal bone. The value of this indicator was the highest in Duroc pigs, lower in 990 animals and the lowest in Pietrain pigs. The cortical index of individual bones was in the following order: III metatarsal bone (31.86) <III metacarpal bone (33.86) <femur (44.75). However, its value did not significantly depend on the intensity of feeding or the breed of pigs.

Comparison of Hittite personal prayers with Sumerian and Akkadian hymns and prayers shows that the imitiation of the Mesopotamian models not only concerned the overall structure and content, but also heavily influenced compositional techniques the Hittite scribes used to create ornamented speech. The examples presented pertain to the macro-structure as well the build-up of passages by means of concentric structures or micro-structural morphological patterns of transitional passages. In the New Hittite period a successful attempt was made at adapting the techniques to create new patterns, which, as a consequence, are specifically Hittite products.

The cryogenic treatment of material has been known to motivate structural stability by rearranging its crystallographic structure in metals and by promoting intermolecular as well as intramolecular rearrangements in polymers. Additionally, in case of polymers reinforced with micro fillers, the structural changes brought about by cryogenic treatment are still largely governed by the polymer matrix itself. Thus, when investigated for their mechanical and tribological properties, the response of polymer/MWCNT nano-composites after cryogenic treatment was found to be depending on the cryo-structural modifications in the polymer matrix, followed by the MWCNT interaction to some extent. The enhancement in the mechanical properties of the polymer/MWCNT nano-composites is attributed to the increasing % crystallinity, changes in crystal structure, conversion of less stable phases into more stable phases, change in the nature of bonding and strengthening of interphase between polymer and MWCNT. Thus, for the cryogenic treatment temperature of -185 °C, the optimum soaking period for PA and PA/MWCNT nano-composite was 24 hrs, whereas for PBT and PBT/MWCNT nano-composite it was 12 hrs and 16 hrs, respectively. This agrees well with the popular claim that each polymer has a specific functional group and/or structural characteristic that readily responds to the cryogenic treatments conditions (irrespective of the filler type, content and/or interaction), thereby, modifying the structure and giving superior properties, which makes cryogenic treatment a material specific process.

Micro-blogging platforms have emerged as marketing tools that multinational companies increasingly utilize to establish and promote their brands. The question is whether they use these platforms strategically, localizing the content and the structure for their target population. This chapter uses case study content analysis to begin answering this question. Social media updates posted by Starbucks over a one-month period on Twitter in the U.S. and on Sina Weibo in China were analyzed using three existing validated frameworks. The results indicate that Starbucks somewhat localizes its posts to its Chinese consumers, in terms of content, symbols, values, and offerings. However, it underutilizes its Sina Weibo page compared to its Twitter counterpart. This chapter goes on to suggest micro-blogging strategies for multinational companies in the Managerial Implications section and concludes with a discussion on the direction of future research for scholars in this field.

A femtosecond laser micro−/nano-texturing was proposed to fabricate the coated and surface treated dies with the tailored textures for surface decoration and surface property control of metal, polymer and glass products. The polygonal model for microtextures with nanotextures by the LIPSS-effect was utilized to fabricate a DLC-coated SKD11 die with a star-shaped emblem. This die was set up into the cassette die set for directly imprinting this emblem into aluminum alloy and PET sheets. The periodic surface structure was synthesized as a surface geometry model to build up the super-hydrophobic surface on the nitrogen supersaturated AISI316 die. This die was also set up into a hot stamping system to directly imprint the hydrophobic surface onto the phosphorous glass products. Through the femtosecond laser micro−/nano-texturing and CNC-imprinting, the metal, polymer and glass product surfaces were optically decorated to have color grating and plasmonic brilliance and functionally controlled to be hydrophobic.

COVID-19 began in 2019, and by the advent of 2020, it had become widespread and adversely affected the world. In this work—Covid Live, COVID-19 data is scraped from an online website, which gives an overview of the status of the pandemic in the desired format. The authors built an application interface using a Python micro web Flask framework. The data scraping uses a multi-threading concept to reduce the program's runtime error, resulting in receiving the data quickly, and faster than existing web crawlers and scrapers. This paper focuses on dealing with storing scraped data in the desired format. It also provides options to hear the audio of the scraped data and to download the scraped data. The authors present visualizations of current trends with scraping period details and demonstrate an efficient application that does the data scraping quickly and efficiently.

Optical storage and laser printer applications require a compact solid-state blue source to achieve greater versatility. One method to obtain this blue light is via Quasi phase matched (QPM) second harmonic generation (SHG).1,2 With QPM we are able to fabricate a high-efficiency blue light source. By inverting the spontaneous polarization with an appropriate period it is possible to phase match any arbitrary wavelength. Several methods have been used to fabricate periodic domain inversion in LiNbO3 and LiTaO3. Ti indiffusion3 or Li outdiffusion4 near the Curie temperature are well-known techniques to reverse the polarization in LiNbO3. Electron beam bombardment5,6,7 has also been employed to make "well"-shaped inverted domains. Periodically poled structures in LiTaO3 can be realized through selective proton exchange (PE) followed by heat treatment near the Curie temperature8. A few micron deep semi-circular shaped domains with a first-order period has been fabricated using proton exchange and a quick heat treatment near the Curie temperature, generating 15mW of blue light9.

In the Suspended ThermoReflectance (STR) technique a microcantilever is heated with a laser power at the free end of the microcantilever and as heat propagates through it, another laser is used to measure the temperature along the beam.[1] In this paper, the heat equation is solved for two-dimensional heat flow in the microcantilever to determine the material’s thermal conductivity and heat capacity. Two of the dimensions of the microcantilever, width and length, are significantly greater than the third dimension, the thickness, leading to the two-dimensional approximation. Two boundaries along the length of the structure and one boundary along the width are assumed to be under Dirichlet boundary conditions, while the other boundary has Neumann condition. The Neumann or flux condition has a Gaussian profile due to the nature of laser beam intensity. The heat equation is solved using under 3 different flux conditions: (1) Steady-state, (2) Transient, and (3) Periodic. A steady-state condition mimics the experimental condition when a continuous wave laser is used to heat the microcantilever’s tip. A transient condition is possible when quickly removing or adding the continuous wave laser’s flux from the microcantilever’s tip using a chopper. Finally, a periodic condition can be achieved when an electro-optic modulator is utilized experimentally. Closed form analytical expressions are evaluated against the finite element model and experimental results for microcantilever beams and micro-structures of Si that have lengths on the order of a mm, width on the order of 100 microns, and thicknesses of 1 micron or less.

Photonic crystals are three-dimensional periodic dielectric structures where the propagation of electromagnetic (EM) waves can be forbidden for a certain range of frequencies.1-2 Early attempts to use these structures in applications like thresholdless semiconductor lasers and single-mode light-emitting diodes have suffered from the difficulties associated with fabricating sub-micron features needed to achieve a band gap at optical frequencies. On the other hand, fabricating photonic band gap (PBG) structures at microwave and millimeter-wave scales3 have been more successful, with numerous demonstrations of PBG-based applications like high directivity millimeter wave antennas, high-quality resonators, microwave cavities for accelerators, and efficient microwave reflectors.

Frequency-Selective Surfaces (FSS) type metasurfaces consist of periodic arrays of antenna elements. They can be scaled from microwave frequencies to the infrared wavelengths where they allow the scattering response to be engineered. This includes the spectral absorptance/emittance. At IR wavelengths, the features sizes of the metasurface are sub-micron which poses manufacturing issues for the meter squared scales required for most heat transfer applications. In this paper, we investigate the use of Microsphere Photolithography for creating spectrally selective metasurfaces. This approach uses a self-assembled array of microspheres as a lens array to focus a lattice of photonic jets into photoresist. These can be used with lift-off to create metal-insulator-metal (MIM) or even five-layer of resonant structures. We study the design constraints and synthesize a broadband emitter in the mid-infrared. The spectral absorptance is measured experimentally using FTIR. The structures are then tested at moderate temperatures to demonstrate the ability to affect surface temperature/heat flux in practical applications.

Recently, structural coloring using hierarchical micro-nano structures as a technical field to implement a color without using a chemical colourants and dye is being developed as an attentional technology. The principle of structural coloring is that by the diffraction or multi-interference of light from a material containing a periodic or quasiperiodic structure on the length scale of the wavelength of visible light. For these reason, our research have verified the structural coloring effect on the polymer substrate by fabricate a hierarchical micro-nano structures. Firstly, we have fabricate a nano and hierarchical micro-nano structured mold for verify the structural size effect. Through the replication of structures on the PMMA substrate, we have measured optical properties in the range of visible light. As a results, the surface of nano structured PMMA showed a blue color according to induced the light. Furthermore, color intensity was increased according to increase the aspect ratio and diameter. In contrast, hierarchical micro-nano patterned surface showed iridescent colors.

Recent experimental and theoretical investigations have shown that periodic subwavelength structured surfaces with periods small compared to the illumination wavelength behave as homogeneous medium, and have suggested interesting applications, such as fabrication of anti-reflection coatings1,2,3, quarter wave plates4, polarizers5, and graded-phase diffractive elements6. The replacement of the periodic structure by a homogeneous medium is often referred as homogenization or effective medium theory (EMT). EMT can be applied to a large variety of physical material properties, such as diffusion constant, magnetic permeability, thermal conductivity, etc. To facilitate the design and fabrication of artificial dielectric elements, one must be able to relate the effective index of the subwavelength structured surface in a simple way.

In this paper, mistuned non-axisymmetric periodic structures are considered. In such a structure, vibration localization, which results in large vibrations in some components of the structure, can occur. Such a behavior is due to mistunings in the structure components, small damping, and weak coupling between components. The efficacy of a passive technique in suppressing vibration localization in mistuned non-axisymmetric periodic structures is examined. The technique is based on adding small components between components of structures. It is shown numerically that the added components suppress vibration localization in mistuned structures. Application of the technique studied in the paper to comb drives of micro electromechanical systems (MEMS) is given.

The overall goal of the research was to understand the processes involved in the development of woolliness in peaches and nectarines. Four specific hypotheses were proposed and in the course of the research evidence was gathered t support two of them and to not support two others. The hypotheses and a summary of the evidence are outlined below. 1. That woolliness arises from an imbalance between the activities of the cell wall pectin degrading enzymes. Using 'Flavortop' nectarines and 'Hermoza' peaches as model systems, storage regimes were manipulated to induce or prevent woolliness. The expression (mRNA abundance), protein content (Western blotting), and activity of polygalacturonase (PG) and pectin esterase (PE) were followed. Expression of the enzymes was not different, but activity and the ratio between PG and PE activities were quite different in fruits developing woolliness or ripening normally. This was also examined by looking at the substrate, the pectin moiety of the cell wall, and i woolly fruit there were more high molecular weight pectins with regions of non-methylated galacturonic acid residues. Taking an in vitro approach it was found a) that PE activity was stable at 0oC while PG activity decreased; b) incubating the calcium pectate fraction of the cell wall with PE extracted from peaches caused the polymers to form a gel characteristic of the visual woolly symptoms in peaches. 2. That continued cell wall synthesis occurs during storage and contributes to structural changes i cell walls and improper dissolution and softening after storage. We tried to adapt our technique of adding 13C-glucose to fruit discs, which was used successfully to follow cell wall synthesis during tomato ripening. However, the difference in sugar content between the two fruits (4% in tomato and 12% in peach) meant that the 13C-glucose was much more diluted within the general metabolite pool. We were unable to see any cell wall synthesis which meant that either the dilution factor was too great, or that synthesis was not occurring. 3. That controlled atmosphere (CA) prevents woolliness by lowering all enzyme activities. CA was found to greatly reduce mRNA abundance of the cell wall enzymes compared to regular air storage. However, their synthesis and activity recovered during ripening after CA storage and did not after regular air storage. Therefore, CA prevented the inhibition of enzyme activation found in regular air storage. 4. That changes in cell wall turgor and membrane function are important events in the development of woolliness. Using a micro pressure probe, turgor was measured in cells of individual 'O'Henry' and 'CalRed' peaches which were woolly or healthy. The relationship between firmness and turgor was the same in both fruit conditions. These data indicate that the development and expression of woolliness are not associated with differences in membrane function, at least with regard to the factors that determine cell turgor pressure. In addition, during the period of the grant additional areas were explored. Encoglucanase, and enzyme metabolizing hemicellulose, was found to be highly expressed air stored, but not in unstored or CA stored fruit. Activity gels showed higher activity in air stored fruit as well. This is the first indication that other components of the cell wall may be involved in woolliness. The role of ethylene in woolliness development was also investigated at it was found a) that woolly fruits had decreased ability to produce ethylene, b) storing fruits in the presence of ethylene delayed the appearance of woolliness. This latter finding has implication for an inexpensive strategy for storing peaches and nectarines.

Training cadets-weightlifters at all stages has a multipurpose orientation, that is why it is important to define and plan a rational combination of the training means use. Distribution of such micro structures in the cycle of training, as the days, months of training, provides effective volume, intensity and other values of physical load distribution. The structure of training cadets-weightlifters is based on taking into account the regularities and principles of sports training as the condition for physical readiness and working capacity increase. Any power oriented sports demands components characteristics in the structure of micro cycles. We consider the methodology of the training lessons organization by the example of the micro cycle of training taking into account bioenergetic profile of cadets-weightlifters. We revealed the necessity to distribute the macro cycle to structural components as the condition for the effectiveness of different variants of the training effects distribution. Materials and methods. We analyzed the range of training lessons among cadets-weightlifters in order to create the variants of gradual training problems solution according to the kinds of training. We analyzed training programs of cadets taking into consideration the level of readiness and their bioenergetic profiles. We created the content of the training work in the micro cycle of the preparatory period for cadets-weightlifters with different bioenergetic profiles. The main material of the research includes the ratio of the training effects volume in one micro cycle taking into account cadets’ bioenergetic profile. Cadets-weightlifters from Tyumen Higher Military-Engineering Command College (military Institute) took part in the research (Tyumen, Russia). Results. We created the content of the training work by the example of one micro cycle for cadets-weightlifters taking into account bioenergetic profile. The created variant of the training loads structure includes the main means of training taking into account the kind of training. Realization orientation in five regimens of work fulfillment with the effectiveness estimation of a total load within one lesson and a week in general is estimated according to a point system. Conclusion. The created variant of a micro cycle considers kinds of training realization taking into account the percentage of the ratio. Taking into account bioenergetic profiles helps to discuss strong and weak sides of muscle activity energy supply mechanisms. We consider the ability to fulfill a long-term aerobic load among the representatives of the 1st and the 2nd bioenergetic profiles. The representatives of the 3rd and the 4th biotype are inclined to fulfill the mixed load. The representatives of the 5th biotype are characterized by higher degree of anaerobic abilities demonstration. The technology of planning the means taking into account the regimens of work realization with point system helps to increase physical working capacity and rehabilitation processes in cadets’ organisms.