The capability of manipulating microparticle in small volumes is fundamental to many biological and medical applications, including separation and detection of cells. The development of microtools for effective sample handling and separation in such volumes is still a challenge. DEP (dielectrophoresis) is one of the most widely used methods in handling the microparticles. In this thesis we show that forces generated by nonuniform electric field (DEP) can be used for trapping and separating the microparticles (latex beads). This work further explores the DEP force based on different electrode geometries and medium conductivity. A micromanipulator for latex bead separation was designed, fabricated and characterized. For the development of DEP manipulator, the fabrication and packaging of microfluidic structure with the microelectrode is crucial for reliable analysis. A combination of SU-8 photoresist and polydimethylsiloxane polymer was used for this purpose. Besides, the DEP manipulator, preliminary study on a Coulter counter was conducted. The Coulter counter works on the principle of resistive pulse sensing. This counter is used for counting the beads as they pass through the microfluidic channel. Its possible integration with the manipulator was also explored.

MEASURING IMPEDANCE OF TISSUES USING A MICROFABRICATED MICROELECTRODE ARRAY By Ashwini Bhat This thesis looks at the possibility of using impedance spectroscopy for differentiating tissue, using a microelectrode array (MEA). The thesis first discusses the background and the motivation for this thesis. It covers the certain basic concepts of the human skin starting from the top epidermis layer all the way to the deep dermis layers of the skin. Then it discusses different types of skin cancer and how they occur, in humans. It also discusses various microfabrication techniques such as oxidation, wet etching, sputtering and photolithography for the creation of a MEA in order to test the tissue. The microfabricated MEA is then used to measure impedance across cooked and raw chicken at different frequencies in order to see if the two types of tissues can be differentiated using their respective impedances. The data shows that the MEA was not able to successfully differentiate the two types of the tissues. It does however list multiple improvements in the fabrication of the MEA and improvements that could be made to the testing procedures which could possible give greater difference in impedance between the two tissues

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This doctoral thesis presents an extensive study on the applications of generalized coherent states (GCS) for the quantum dynamics of many-body systems. The research starts with exploring the fundamental properties of generalized coherent states, which are created by generators of the SU($M$) group acting on an extreme state, and demonstrating their role in representing ideal quantum condensates. A significant feature is the relationship between generalized coherent states and the more standard Glauber coherent states (CS). Similarities in their overcomplete and non-orthogonal nature are shown, alongside crucial differences with respect to $U(1)$ symmetry and entanglement properties, which generalized coherent states solely adhere to. Furthermore, this thesis delves into the nonequilibrium dynamics of GCS as well as Glauber CS under nonlinear interactions. Combining analytical analysis and numerical calculations, it is found that while their two-point correlation functions are equivalent in the thermodynamic limit, their autocorrelation functions exhibit distinctly different characteristics. It is proven analytically that the autocorrelation functions of the evolved GCS relate to the ones of the corresponding Glauber CS through a Fourier series relation, which arises due to the $U(1)$ symmetry of the GCS. A substantial part of this thesis is dedicated to investigating the dynamics of the Bose-Hubbard model, incorporating both nonlinear interaction and tunneling term. This investigation introduces a novel approach which employs an Ansatz for the wave function in terms of a linear combination of GCS, where the differential equations of all the variables are determined by the time-dependent variational principle without truncation. This innovative method is adeptly applied to the nonequilibrium dynamics in various scenarios, from the bosonic Josephson Junction model where some fundamental quantum effects can be revealed by a handful of GCS basis functions, to large system size implementations of the Bose-Hubbard model, where the phenomenon of thermalization can be observed. The proposed variational approach provides an alternative way to study the time-dependent dynamics in many-body quantum systems conserving particle number. The final focus of this thesis is on the boson sampling problem within a linear optical network framework. Again adapting a linear combination of GCS, an exact analytical formula for the output state in standard boson sampling scenarios is derived by means of Kan's formula, showcasing a computational complexity that increases less severely with particle and mode number than the super-exponential scaling of the Fock state Hilbert space. The reduced density matrix of the output state is obtained by tracing out one subsystem. This part of the study extends to examining the properties of the subsystem entanglement creation, and offering novel perspectives on entanglement entropy differences between global and local optical networks. This thesis makes several contributions to the field of quantum many-body systems, particularly highlighting the potential applications of GCS. The presented research offers a new variational method to the nonequilibrium dynamics, and paves the way for future explorations and applications in quantum simulations, quantum computing and beyond.

O presente trabalho tem como objetivo desenvolver um processo de fabricação de elementos micro-ópticos utilizando-se litografia por feixe de elétrons, empregando o resiste SU-8, negativo e amplificado quimicamente, sobre substrato de Si. Para tanto, é realizado o estudo dos parâmetros do efeito de proximidade a, b e h para se modelar e controlar os efeitos do espalhamento dos elétrons no resiste e no substrato, e se altera o processamento convencional do SU-8 para se obter um processo com baixo contraste. A determinação dos parâmetros do efeito de proximidade para o sistema de escrita direta e amostra SU-8 / Si é feita experimentalmente e por simulação de Monte Carlo. Particularmente, verifica-se a dependência dos mesmos com a profundidade do resiste. Primeiramente utilizando o software PROXY, obtêm-se a, b e h da observação de padrões de teste revelados. Chega-se a 4m para o parâmetro () que mede o retroespalhamento dos elétrons pelo substrato e 0,7 para a relação (h) entre a intensidade destes com aquela dos elétrons diretamente espalhados pelo resiste (alcance dado por a). Ainda, com esses dados, estima-se o diâmetro do feixe do microscópio eletrônico de varredura a partir da equação de aproximação de espalhamento direto para pequenos ângulos (a = 128nm na superfície do resiste) e se determina a resolução lateral do processo (a = 800nm na interface resiste/ substrato, para um filme de 2,4m). Em seguida, usa-se o software CASINO para se calcular os parâmetros de proximidade a partir da curva de densidade de energia dissipada no resiste obtida pela simulação da trajetória de espalhamento dos elétrons. Confrontam-se, finalmente, os valores obtidos pelos dois métodos. Em relação ao processamento do resiste SU-8, são determinadas as condições experimentais para a fabricação de estruturas tridimensionais por litografia de feixe de elétrons. Especificamente, busca-se desenvolver um processo com características (espessura, contraste, sensibilidade e rugosidade) adequadas para a fabricação de micro-dispositivos ópticos. Inicia-se com o levantamento das curvas de contraste e da sensibilidade do SU-8 para determinadas temperaturas de aquecimento pós-exposição. Obtém-se contraste abaixo de 1 para aquecimento pós-exposição abaixo da temperatura de transição vítrea do resiste, mantendo-se sensibilidade elevada (2C/cm2). Em seguida, mede-se a rugosidade da superfície do filme revelado para diferentes doses de exposição. Para finalizar, submete-se a amostra a um processo de cura e escoamento térmico, para melhorar a dureza e a rugosidade do resiste a ser utilizado como dispositivo final Consegue-se um valor de rugosidade (40nm) inferior a 20 vezes o comprimento de onda de diodo laser de eletrônica de consumo. Por fim, é produzido um dispositivo com perfil discretizado em 16 níveis como prova de conceito. / This work aims at developing an electron-beam lithography process for the fabrication of microoptical elements using the negative tone chemically amplified resist SU-8 on Si substrate. A study of the proximity effect parameters a, b and h is carried out to model and control the electron scattering both in the resist and in the substrate, and the SU-8 standard processing conditions are changed to achieve a low contrast process. The determination of the SU-8 / Si proximity effect parameters and its dependence with resist depth is done employing an experimental method and through Monte Carlo simulations. First, a, b and h are obtained comparing exposed patterns calculated by the software PROXY. b, the parameter which measures the backscattering of the electrons by the substrate, is equal to 4m and the value of h, the ratio of the dose contribution of backscattered electrons to that of the forward scattered (related to a), is 0.7. The extrapolation of exposed patterns data is used to estimate the scanning electron microscope beam diameter through the equation for low angle scattering (a = 128nm at the resist surface) and the lateral resolution of the process is determined (a = 800nm at the resist/ substrate interface, for a 2.4m film). With aid of the software CASINO, Monte Carlo simulations of the scattering trajectories of electrons in substrate and resist materials are calculated, recording the energy that they dissipate through collisions along their path. The results obtained representing the profile of the energy dissipated in the resist are used to determine the proximity effect parameters. The experimental method results are compared to that obtained by simulation. Regarding the SU-8 processing, the process parameters for the fabrication of three-dimensional structures by electron-beam lithography are determined. The process is designed to have specifications (thickness, contrast, sensitivity and surface roughness) suitable for microoptical elements fabrication. It begins with the determination of the SU-8 contrast curve and its sensitivity for specific post-exposure bake temperatures. A below the unit contrast process with high sensitivity (2C/cm2) is achieved postannealing the sample below the resist glass transition temperature. The film surface roughness is measured after resist development for different exposure doses, and a controlled hardbake (cure) and reflow is carried to enhance both the mechanical properties and the surface roughness of the structures that will remain as part of the final device. A RMS roughness of 40nm, lower than 20 times the wavelength of consumer electronics laser diode, is obtained. The electron-beam process designed is applied to the fabrication of a microelement with a 16-level profile discretization.

In meiner Doktorarbeit habe ich das Potential zwischen zwei statischen Quarks in der Confinement ``Phase'' des SU(2) Higgs Modells untersucht. Statische Quarks sind externe Quellen in der fundamentalen Darstellung der Eichgruppe. In reinen nicht-Abelschen Eichtheorien w\"achst das Potential zwischen einem statischen Quark und einem statischen Anti-quark (statisches Potential genannt) linear mit dem Abstand zwischen den Quarks. Dieses Verhalten des Potentials wird lineares Confinement genannt und wurde mit Gittersimula tionen bis zu grossen Abst\"anden und nahe am Kontinuumslim es beobachtet. Wenn dynamische Materiefelder vorhanden sind, wird erwartet, dass das statische Potential bei grossen Abst\"anden abflacht: Der Grund ist die Abschirmung der statischen Quarks durch Paarerzeugung von leichten Quark Anti-quark Paaren. Die Abflachung des statischen Potentials nennt man String Breaking. Der Stand der Dinge am Anfang meiner Doktorarbeit war, dass String Breaking in nicht-Abelschen Eichtheorien mit Materiefeldern noch nicht beobachtet wurde. Im Gegenteil, die Gittersimulationen von QCD mit dynamischen Fermionen zeigten (und zeigen noch) einen linearen Zuwachs des Potentials bei Abst\"anden, wo das String Breaking eigentlich erwartet wird (aus einer Sch\"atzung in der quenched Approximation der QCD). Die Confinement ``Phase'' im SU(2) Higgs Modell hat Eigenschaften, die der QCD \"ahnlich sind, insbesondere wird das String Breaking erwartet. Deswegen ist die Bestimmung des statischen Potentials im SU(2) Higgs Modell eine wichtige Untersuchung der relevanten Eigenschaften des String Breaking Ph\"anomens. Ich habe das SU(2) Higgs Modell in der Confinement ``Phase'' auf dem Gitter simuliert: Die Resultate zeigen deutlich das String Breaking. Desweiteren kann auch das erste angeregte statische Potential bestimmt werden. Der entscheidende Punkt sind die Korrelationen, die man benutzt, um das statische Potential zu bestimmen. In der reinen Eichtheorie wird das statische Potential aus den Wilson Loops bestimmt, die den ``String Zustand'' des Eichfeldes gut beschreiben. String steht hier f\"ur die Eichfeldkonfiguration, die das lineare Confinement der Quarks verursacht. In Anwesenheit von Materiefeldern erwartet man, dass bei grossen Abst\"anden das statische Pot ential durch das Potential zwischen zwei statisch- leichten Mesonen (Bindungszust\"anden eines statischen Quarks mit dem dynamischen leichten Quarkfeld) beschrieben wird. Die Methode, die ich verwendet habe, um das statische Potential zu bestimmen, basiert auf eine Mischung von ``String-'' und ``Zwei-Meson Zust\"anden''. Mit einem Variationsprinzip wird die beste lineare Kombination solcher ``Zust\"anden'' bestimmt, welche die Eigenzust\"ande des Hamiltonoperators approximiert. Dank der Bestimmung des ersten angeregten Potentials, konnte auch die Interpretation des String Breakings als Level Crossing Ph\"anomen zwischen ``String'' und ``Meson Zust\"anden'' best\"atigt werden. In dem zweiten Teil meiner Doktorarbeit habe ich die Frage des ``Kontinuumlimes'' untersucht. Das String Breaking wurde f\"ur einen speziellen Satz von Parametern beobachtet: die Frage war, wie stark diese Resultate vom gew\"ahlten Gitterabstand abh\"angig sind (Cutoff-Effekte). Diese Frage f\"uhrt unmittelbar zur Untersuchung von Linien konstanter Physik im Parameterraum des SU(2) Higgs Modells. Obwohl in m einer Arbeit noch keine definitive Methode gefunden worden ist, um diese Linien zu konstruieren, konnte ich das Skalierungsverhalten der statischen Potentiale bei Variation des Gitterabstandes um einen Faktor zwei untersuchen. Die Resultate zeigen \"uberraschend kleine Cutoff-Effekte! Die M ethode, welche ich in meiner Arbeit verwendet habe, ist auch in der QCD zu verwenden, um das String Breaking zu beobachten. / The static potential in the confinement ``phase'' of the SU(2) Higgs model is studied. In particular, the observation of the screening (called {\em string breaking}) of the static quarks by the dynamical light quarks leading to the formation of two static-light mesons was not observed before my work in non-Abelian gauge theories. The tool that I employ is lattice gauge simulation. The observable from whic h the spectrum of the Hamiltonian in presence of two static quarks can be extracted, is a matrix correlation whose elements are constructed not only from string-type states represented by Wilson loops (like in pure gauge theories). Additional matrix elements representing transitions from string-type to meson-type states and the propagation of meson-type states are taken into account. From this basis of states it is possible to extract the ground state and first excited state static potentials employing a variational method. The crossing of these two energy levels in the string breaking region is clearly visible and the inadequacy of the Wilson loops alone can be demonstrated. I also address the question of the lattice artifacts. For this purpose lines of constant physics in the confinement ``phase'' of the model have to be constructed. This problem has only partially been solved. Nevertheless it is possible to show that the static potentials have remarkable scaling properties under a variation of the lattice spacing by a factor two and are almost independent of the quartic Higgs coupling.

Magistro darbo objektas – ryšių su visuomene panaudojimo galimybės prekinio ženklo komunikacijoje. Darbo tikslas - išanalizuoti ryšių su visuomene panaudojimą prekinio ženklo komunikacijoje. Pagrindiniai darbo uždaviniai: identifikuoti prekinį ženklą bei ryšius su visuomene, jų elementus bei ypatumus; išanalizuoti ryšių su visuomene panaudojimo prekinio ženklo komunikacijai galimybes ir daromą poveikį; ištirti ryšių su visuomene naudojimą Lietuvos prekinių ženklų komunikacijoje. Naudojantis literatūros šaltinių analizės bei lyginamuoju metodais bei kiekybine publikacijų analize, prieita prie išvados, kad efektyviausiai ryšiai su visuomene panaudojami prekinio ženklo sukūrimo, įvedimo į rinką stadijoje. Prekinis ženklas - tai prekės ženklas su pridedamąja jo verte, kuri sukuriama naudojant įvairias marketingo komunikacijos priemones, todėl prekinis ženklas egzistuoja tik vartotojo sąmonėje. Stiprus prekinis ženklas sukuriamas atsižvelgiant į tam tikrus dėsnius: vienas prekinis ženklas gali asocijuotis tik su vienu produktu ar produktų kategorija (kategorijoje produktai turi būti panašūs savo charakteristikomis); prekinio ženklo komunikacija turi būti nuoseklus procesas; sukurtą prekinį ženklą reikia įvesti į rinką ir palaikyti atitinkamai ryšių su visuomene ir reklamos pagalba; kiekvienas prekinis ženklas turi atrasti ir „pasisavinti“ tam tikrą žodį, kuris vėliau sukeltų norimas asociacijas vartotojo sąmonėje bei sukurti kokybės iliuziją, naudojant vardą ir aukštą kainą... [toliau žr. visą tekstą] / The object of this work – public relations practice opportunities in brand communication. Aim of this work – to analyze public relations practice in brand communication. The fundamental objectives are to identify brand and public relations, their elements and peculiarities; to analyze public relations practice opportunities and impacts in brand communication process; to analyze public relations practice in Lithuania’s brands communication. Using survey of analytical-theoretical method, there was come to a conclusion, that the most effective public relations practice exist in brand establishing and in introducing stage. Brand is the product or services with added values, which is created through marketing communication elements and exist only in consumers mind. Strong brands are created using special laws, which determines that: one brand could be connected only with one product or service; brand communication should be a consistent process; public relations should be used in brand introducing to the market stage while for the brand maintenance it is effective to use advertising; every brand should be associated with one main word. Organization should plan brand communication, its process and tools in advance. The main tools of brand communication are elements of marketing communication. The particularity of brand, the stage of its life cycle and stakeholders influences decision which components will be used in brand communication. Brand identity should be used properly. When... [to full text]