Dissertations / Theses on the topic 'Defect dimensions'
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Söderberg, Alexander. "Anomalous Dimensions in the WF O(N) Model with a Monodromy Line Defect." Thesis, Uppsala universitet, Teoretisk fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-317546.
Full textPavlovitch, André. "Problemes de structure et de defauts de structure dans les pavages aperiodiques bi-dimensionnels (quasi-cristaux)." Paris 6, 1988. http://www.theses.fr/1988PA066467.
Full textНощенко, Сергій Петрович. "Автоматизований вихрострумовий дефектоскоп для моніторингу стану елементів конструкцій літальних апаратів." Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/38193.
Full textThe master's dissertation contains 82 letters, 25 figures, 23 tables, 18 sources according to the list of references. The dissertation presents an analysis of structural elements as an object of NC control. The expediency of using eddy current non-destructive testing to detect defects such as surface and subsurface fatigue cracks and evaluate their parameters has been confirmed. A review of possible methods of processing the received signals according to the available hodographs of the relative applied voltage. Types of overhead and through-flow eddy current converters are considered. The analysis confirmed the feasibility of using an eddy current transducer of the transformer type with differentially connected measuring coils. During the analysis of hodographs of the applied stress from the defect, the possibilities of a more detailed quantitative assessment of the defect parameters according to the VSP output signal were revealed. The approximate calibration characteristics for the defect parameters obtained from the hodograph of the applied stress from the defect made it possible to trace the peculiarities of the phase and amplitude change of the received GSP signal from the depth and depth of the defect. . The proposed technical solutions make it possible to automate the process of control over the decision on the presence of a defect and the evaluation of numerical indicators of defects.
Fornara, Pascal. "Modélisation et simulation numérique de la croissance des siliciures pour la microélectronique." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10082.
Full textBogaert, Kevin Christopher. "Defect-driven processing of two-dimensional transition metal dichalcogenides." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122072.
Full textThesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 149-161).
Two-dimensional transition metal dichalcogenides (TMDs) are an emerging class of semiconductor materials that offer exciting new properties for future electronic and optoelectronic applications. However, many ongoing challenges related to synthesis and processing must be overcome before this nascent technology can become industrially viable. In this thesis, processing-related phenomena relevant to the fabrication of TMD heterostructures, alloys, and nanoporous membranes are presented. This thesis begins with an investigation of the role of substrate temperature in two-step chemical vapor deposition (CVD) growth of MoS₂/WS₂ heterostructures. We demonstrate diffusion-mediated synthesis of inverted lateral heterostructures following low MoS2 growth temperatures in the second CVD step and homogeneous Mo[subscript x]W[subscript 1-x]S₂ alloyed crystals following higher MoS₂ growth temperatures.
Investigating the nature of this diffusion-mediated process, we identify an energetically favorable atomistic model proposing that transition metal diffusion is driven by a heterogeneous distribution of sulfur vacancies. This model is corroborated by the synthesis of a composition-graded Mo[subscript x]W[subscript 1-x]S₂ alloy crystals in which the final-stage spatial distribution of transition metal atoms correlates with intermediate-stage distribution of point defects. These heterogeneous crystals allow for correlation of the local optical properties with the local composition, demonstrating a variation in photoluminescence intensity spanning two orders of magnitude and reaching the maximum value for equicompositional alloy Mo₀.₅W₀.₅S₂ (x=0.5). Furthermore, the correlation between intermediate-stage distribution of point defects and final-stage spatial distribution of transition metal atoms enables the opportunity for bespoke patterning.
Utilizing a laser annealing technique, we demonstrate the ability to locally induce defects that define the regions of preferential nucleation during subsequent CVD growth. Finally, defect processing is also demonstrated in nanoporous TMD membrane applications. Combining modeling with experimentation, we demonstrate the relationship between vacuum annealing time and temperature with nanopore properties such as average radius and edge structure. Control of these properties is essential for the fabrication of functional nanoporous membrane devices for sensing, filtration, and energy applications. This thesis motivates further work on TMD processing in pursuit of developing a fundamental understanding of the defect-driven diffusion mechanism, a larger library of interesting TMD compositions and structures, as well as industrially viable TMD devices.
by Kevin Christopher Bogaert.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Materials Science and Engineering
Schmidt, Robert. "Defects in Higher-Dimensional Quantum Field Theory." Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-71937.
Full textCaulier, Yannick. "Surface defect classification based on one-dimensional sensors and structured illumination." Aachen : Shaker, 2008. http://d-nb.info/991379101/04.
Full textRezaei, Seyed Emad. "Defect Engineering: Novel Strengthening Mechanism for Low- Dimensional Zinc Oxide Nanostructures." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1532902032338622.
Full text任穎華 and Wing-wa Yam. "Two dimensional membrane and bending elements with defects." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31226991.
Full textYam, Wing-wa. "Two dimensional membrane and bending elements with defects /." Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B24367370.
Full textMagyar, Peter. "Quelques aspects du transport électronique bidimensionnel : études théoriques en champ magnétique faible et fort." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10025.
Full textGladikowski, Jens. "Solitons in low-dimensional sigma models." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/5077/.
Full textRice, Marie C. "Healing of defects in a two-dimensional granular crystal." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92204.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 52-54).
Using a macroscopic analog for a two dimensional hexagonal crystal, we perform an experimental investigation of the self-healing properties of circular grain defects with an emphasis on defect orientation. A circular grain defect is introduced into a nearly perfect hexagonal array of millimeter-sized spherical brass particles enclosed in a square tray. The array is oscillated uniaxially, causing the particles to vibrate randomly with respect to each other, which in turn induces the curved grain boundary around the misoriented defect region to migrate toward its center of curvature. Images of the healing crystal are acquired and analyzed to determine particle locations and quantify the size of the defect at prescribed time intervals. This procedure was repeated ninety-four times in order to collect data on a range of misorientations. In some cases, the misorientation angle varied significantly during healing so both initial misorientation and time averaged misorientation angle were considered as possible driving variables for healing rate. Healing times were fit to an exponential curve dependent on misorientation angle but there was a high degree of scatter from this correlation. Despite this variation in path shape, there was some correlation between healing time and misorientation, though there was significant scatter. In an effort to identify the source of this scatter by differentiating between defects with different healing times but nearly the same misorientation angle, the time dependence of healing rate was investigated. This more detailed examination of the time evolution of defect size revealed substantial variation in time dependence type. Both linear and nonlinear time dependence of defect area size was observed among the healing samples. The nonlinear time dependence of defect size was not common among defects with low healing times. However, degree of linearity did not effectively distinguish between defects with similar misorientation and widely different healing times nor did it correlate meaningfully with misorientation. Though the self-healing behavior of grain defects has not yet been fully characterized, there is evidence that geometric parameters influence overall healing time.
by Marie C. Rice.
S.B.
Wong, Tsz Chun. "Experimental and theoretical investigation of optical nonlinearity in one-dimensional photonic crystal with central defect mode /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202009%20WONG.
Full textCaulier, Yannick [Verfasser]. "Surface Defect Classification Based on One-Dimensional Sensors and Structured Illumination / Yannick Caulier." Aachen : Shaker, 2008. http://d-nb.info/1161303618/34.
Full textSchnur, Christopher. "Electron Beam - Powder Bed Fusion Of Alloy 718 : Influences Of Contour Parameters On Surface And Microstructural Characteristics." Thesis, Högskolan Väst, Avdelningen för Industriell ekonomi, Elektro- och Maskinteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-14318.
Full textYoussef, Amanda. "Three-dimensional defect characterization : focused ion beam tomography applied to tin sulfide thin films." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92112.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 81-86).
Porosity is postulated to be one of the reasons for the low efficiency of tin sulfide-based devices. This work is a preliminary investigation of the effects of two film growth parameters deposition rate and substrate temperature - on porosity. We employ the focused ion beam tomography technique to characterize and quantify porosity in tin sulfide thin films. We then generate 3D reconstructions of pores inside milled volumes from the films and quantify pore volumes. To explain the results, we employ nucleation theory and develop two different models: (a) a thermodynamic model that assumes pores form primarily from an effect known as "self-shadowing," whereby growth-rate anisotropy results in some grains that grow faster than their neighbors, and (b) a kinetic model that assumes a diffusion-driven process of void formation. We show that both models qualitatively support the experimental results, providing insight into process-structure relations that may improve film quality during growth.
by Amanda Youssef.
S.M.
Chen, Qu. "Structural studies of defects in two-dimensional materials with atomic resolution." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:392f2b1d-0488-4d10-96d9-817def04db2a.
Full textSaxton, Patrick C. (Patrick Charles) 1975. "Reducing powder bed layer defects in slurry-based three dimensional printing." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9423.
Full textIncludes bibliographical references (leaf 141).
Slurry-based Three Dimensional Printing is being used to create ceramic parts directly from CAD files. Discrete slurry layers are deposited, into which a binder material is selectively ink-jet printed. This process is repeated until the last layer of the powder bed is deposited. Afterwards, the powder bed is re-dispersed in water, leaving behind the printed green part. The green part is then sintered to full density. This thesis focuses on methods of depositing the slurry layers. Currently, slurry layers are deposited by nozzle rastering. In this approach, a nozzle mounted to an x-y linear positioning system deposits adjacent discrete lines of slurry on a powder bed. Powder beds produced by nozzle rastering contain defects that occur between line and layer interfaces. The top surface has an inherent roughness due to the peaks and valleys between discrete lines. Line merging is a new method of slurry layer deposition that has been developed in an effort to eliminate inter-line defects, improve layer surface finish, and increase throughput This new technique has been used to rapidly produced slurry layers containing fewer internal defects and smooth surface finishes. Line merging occurs when adjacent lines of slurry are deposited in rapid succession such that they merge together prior to slip casting. Line merging differs from nozzle rastering in two ways: lines are deposited in only one direction (during the return pass the nozzle is put into a catch position), and the cycle time between depositing lines is reduced from approximately I second to as little as 0.1 second. A model was developed in an effort to identify the conditions required to achieve successful line merging, while avoiding layer defects such as bubbling and irregular surface finish caused by slurry migration. This model emphasized three relationships: the ratio of cycle time for line deposition to slip casting time for a slurry layer, the ratio of line width to line spacing, and the inverse of the width of the wet slurry zone where lines have merged prior to slip casting. A 3-D plot was constructed relating an objective function comprised of the three relationships to the control parameters (flow rate divided by nozzle velocity and cycle time). A plot for each alumina slurry solids loading was used to guide experiments. These experiments supported the model, though some relationships were proved more accurate than others. The model was ultimately used to target the ideal line merging conditions that were used to produced a 60 layer alumina powder bed out of 50 micron thick layers of 18 vol% alumina slurry. This powder bed exhibited excellent surface finish, with a maximum variation of 11 microns peak to valley. SEM analysis of cross-sections revealed that internal defects between deposited lines, previously seen with nozzle rastering, had been eliminated. Micro-bubbles along the interface between layers persisted, however. Follow-up SEM analysis of a 5 layer powder bed built with 22 vol% alumina slurry revealed no inter-line or inter-layer defects.
by Patrick C. Saxton.
S.M.
Stieler, Daniel Paul. "Characterization of defect cavities and channel-drop filters in the three dimensional woodpile photonic crystal." [Ames, Iowa : Iowa State University], 2008.
Find full textAfsharian, Mohsen [Verfasser]. "The Two-Dimensional, Rectangular, Guillotineable-Layout Cutting Problem with Defects / Mohsen Afsharian." Aachen : Shaker, 2013. http://d-nb.info/1051575575/34.
Full textXu, Tao. "Low-dimensional atomic-scale multiferroics in nonmagnetic ferroelectrics from lattice defects engineering." Kyoto University, 2017. http://hdl.handle.net/2433/227622.
Full textLassige, Timothy A. "Comparison of septal defects in 2-D and 3-D echocardiography using active contour models." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/13839.
Full textO'Neill, Darren Frances. "An investigation of excrescence drag due to manufacturing defects on two-dimensional surfaces." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246541.
Full textBoyers, Albert S. "SPECT myocardial perfusion scans : a left ventricular defect size estimation algorithm and a three dimensional computer simulation." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/14879.
Full textLaw, Alex. "Dimensions of restructuring : state, capital and labour in the defence industry in Scotland." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/21351.
Full textBaniasadi, Fazel. "Structure Characterization and Electronic Properties Investigation of Two-Dimensional Materials." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103904.
Full textDoctor of Philosophy
Graphite (consisting of graphene as building blocks) and TMDS in bulk form are layered and with exfoliation one can reach to few layers which is called two-dimension. Two dimensional materials like graphene have been used in researches vastly due to their unique properties, e.g. high carrier mobility, and tunable electronic properties. Transition metal dichalcogenides (TMDs) with a general formula of MX2, where M represents transition metal elements (groups 4-10) and X represents chalcogen elements (S, Se or Te), are another family of two-dimensional materials which have been extensively studied in the past few years. Besides exfoliation, there are also synthesis methods to produce two dimensional materials, e.g. chemical vapor deposition and chemical vapor transport. Normally, after synthesizing these materials, researchers investigate structure and electronic properties of these materials. There might be some atoms which no longer exist in the structure; hence, those are replaced by either vacancies or other elements which all of them are called defects. In chapter 1, defects in graphene and transition metal dichacolgenides were investigated, carefully. Later, dynamic behavior of defects in these materials were investigated and finally, the effect of defects on the electronic properties of the two dimensional materials were investigated. Chapter two talks about a case study which is two dimensional 1T-PtSe2. In this chapter, 5 different kinds of defects were studied using scanning tunneling microscopy and spectroscopy investigations and density functional theory was used to prove our assumptions of the origin of defects. Also, another thing which is investigated by researcher is that how atoms in two dimensional materials vibrate and how the number of layers in the two dimensional material influences vibrations of atoms. Other than this, electronic properties of these materials is dependent upon the number of layers. When these materials are synthesized, there is a stress applied to the material due the mismatch between the material and its substrate, so it is worth investigating the effect of stress (strain) on the structure, and electronic properties of the material of interest. For this purpose, 2M-WS2 was exfoliated on Si/SiO2 substrate and the layer dependency of its vibrational modes was investigated using Raman spectroscopy and density functional theory calculation. Also, in order to investigate the influence of stress (strain) on the electronic properties of two dimensional 2M-WS2, a single monolayer of this materials underwent a series of strains in density functional theory calculations and the effect of strain on the electronic properties of this material was investigated.
Tuesday, Andrew J. "Modeling Atomic Defects in a Two-Dimensional Lennard-Jones Lattice Using Molecular Dynamics Simulations." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1334579948.
Full textHsiao, Ming-Siao. "Crystallization, Crystal Orientation and Morphology of Poly(Ethylene Oxide) Under One Dimensional Defect-Free Confinement on the Nanoscale." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1247266725.
Full textKrymowski, Kevin E. "The Effect of Ligand Variation on Two-Dimensional Materials." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1495802952188467.
Full textJafri, Syed Hassan Mujtaba. "Building Systems for Electronic Probing of Single Low Dimensional Nano-objects : Application to Molecular Electronics and Defect Induced Graphene." Doctoral thesis, Uppsala universitet, Tillämpad materialvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-160630.
Full textHartman, Christie Ann. "The genetic etiology of attention-deficit/hyperactivity disorder and its dimensions: Linkage to chromosome 6p." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/dissertations/fullcit/3186932.
Full textFoteinopoulou, Stavroula. "Electromagnetic Wave Propagation in Two-Dimensional Photonic Crystals." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/822058-9BqHHS/native/.
Full textPublished through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2048" Stavroula Foteinopoulou. 12/12/2003. Report is also available in paper and microfiche from NTIS.
Perez, Blanco Isabel Cristina [Verfasser]. "A model development for reconstruction of three-dimensional defects based on MFL signals / Isabel Cristina Perez Blanco." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2020. http://d-nb.info/1224883586/34.
Full textAsenjo, Andrews Daniel Arthur. "Sobre la Transición Sólido-Líquido y la Inestabilidad Mecánica Provocada por Defectos en Dos Dimensiones." Tesis, Universidad de Chile, 2009. http://repositorio.uchile.cl/handle/2250/102072.
Full textIve, Jeremy George Augustus. "The local dimensions of defence : the standing army and militia in Norfolk, Suffolk and Essex, 1649-1660." Thesis, University of Cambridge, 1987. https://www.repository.cam.ac.uk/handle/1810/244865.
Full textZareie, Rajani Hamid Reza. "Development of a three-dimensional multi-scale model to study the formation of solidification defects in fusion welding." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57601.
Full textApplied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
Kruták, Martin. "Automatická kontrola kvality výrobku z obrazu." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2019. http://www.nusl.cz/ntk/nusl-403118.
Full textDas, Ajoy Kumar. "Health Assessment of Three Dimensional Large Structural Systems Using Limited Uncertain Dynamic Response Information." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/268597.
Full textLee, Soon Gi. "Quantitative Characterization of Processing-Microstructure-Properties Relationships in Pressure Die-Cast Mg Alloys." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11552.
Full textInfante, Fulvio. "Development of magnetic microscopy techniques for failure localization on three-dimensional circuits." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14394/document.
Full textIn this work, new developments on localization techniques for three-dimensional electronic components are shown and demonstrated. These are performed through the introduction of simulations for an already existing technique: Magnetic Microscopy (MM). In the first part, a state of the art of new three-dimensional components assembly is described. It is then followed by an up to date FA process description, while keeping it as general as possible. A description of component reliability, in function of the time of usage of such devices is shown, allowing the reader to understand why the need for Failure Analysis arose in the first place. The whole process of Failure Analysis is then described in a general way, starting from the electrical characterization of the defect, to the final results. The second part then explains the Magnetic Microscopy technique in more detail. This technique uses the properties of the magnetic fields, which are generated by the currents, to precisely localize the defects in standard electronic components. The third part of this work is dedicated to the Simulation Approach (SA): a new methodology developed to extend the capabilities of Magnetic Microscopy techniques. The basic principle is that of comparing magnetic simulations generated by hypothetical current distributions to the magnetic acquisitions of the real current distribution. The evaluation of the correlation between the two then gives a measurement of the distance between them. This approach is able to overcome the previous limitations of the technique: the defect can now be localized in three dimensions. Finally, in the fourth part the new technique is applied and validated on a set of case studies
Sreedhar, Aswin. "Automatic techniques for modeling impact of sub-wavelength lithography on transistors and interconnects and strategies for testing lithography induced defects." Connect to this title online, 2008. http://scholarworks.umass.edu/theses/80/.
Full textHunter, Sri Mulyati. "The "changing dimensions" of the Australia-Indonesia bilateral relationship from 1996 to October 2002 in the defence and security context /." Diss., Title page, contents and introduction only, 2002. http://web4.library.adelaide.edu.au/theses/09AR/09arh947.pdf.
Full textNeves, Alyson Bruno Fonseca. "VÓRTICES NA REDUÇÃO DIMENSIONAL DO MODELO DE MAXWELL-CARROLL-FIELD-JACKIW-HIGGS." Universidade Federal do Maranhão, 2012. http://tedebc.ufma.br:8080/jspui/handle/tede/736.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
This monograph presents the study of vortices BPS in a model obtained by dimensional reduction of the (1+3)−D Maxwell-Carroll-Field-Jackiw-Higgs s electrodynamics to (1+2)−D. The Maxwell-Carroll-Field-Jackiw-Higgs model is defined by the following Lagrangian density L1+3 = −14FμνFμν −14 ϵμνκλ (kAF )μ AνFκλ + |Dμϕ|2 − V (|ϕ|), the first two terms constitute the CPT-odd electrodynamics of the standard model extension (SME). The term ϵμνκλ (kAF )μ AνFκλ is called the Carroll-Field-Jackiw s term. The dimensional reduction of this model is given by the following Lagrangian density L1+2 = − 14FμνFμν +s4 ϵμνκAμFνκ +12∂μψ∂μψ −12ϵμνκ (kAF )μ ψ∂νAκ−12 ϵμκν (kAF )μ Aκ∂νψ + |Dμϕ|2 − e2ψ2 |ϕ|2 − V (|ϕ|2 , ψ), it is observed that if (kAF )μ = 0 we obtain the Maxwell-Chern-Simons-Higgs (MCSH) model. This way, our planar model is a MCSH model modified by an interaction between the gauge field Aμ and the neutral scalar field ψ whose coupling constant is (kAF )μ, the Lorentz-violating vector field background. The existence of stable BPS v´ortices implies in a null (kAF )0 component. The study shows that the influence of the Lorentz violation is clearly manifested when the vortex s winding number is greater than 1.
Esta dissertação apresenta o estudo de vórtices BPS num modelo obtido pela redução dimensional da eletrodinâmica de Maxwell-Carroll-Field-Jackiw-Higgs de (1+3)-dimensões para (1+2)-D. A densidade lagrangiana do modelo de Maxwell-Carroll-Field-Jackiw-Higgs é definido por L1+3 = −14 FμνFμν − 14 ϵμνκλ (kAF )μ AνFκλ + |Dμϕ|2 − V (|ϕ|), os dois primeiros termos constituem a eletrodin amica CPT- ímpar do modelo padrão estendido (SME). O termo ϵμνκλ (kAF )μ AνFκλ é o chamado termo de Carroll-Field-Jackiw. A redução dimensional deste modelo é dado pela seguinte densidade lagrangiana L1+2 = − 14 FμνFμν + s4 ϵμνκAμFνκ + 12 ∂μψ∂μψ −12 ϵμνκ (kAF )μ ψ∂νAκ − 12 ϵμκν (kAF)μ Aκ∂νψ + |Dμϕ|2 − e2ψ2 |ϕ|2 − V (|ϕ|2 , ψ), observamos que se (kAF)μ = 0 se obtém o modelo de Maxwell-Chern-Simons-Higgs (MCSH). Desse modo o modelo planar representa um modelo de MCSH modificado por uma interação entre o campo de gauge Aμ e o campo neutro ψ cuja constante de acoplamento é (kAF )μ, o campo de fundo vetorial portador dos efeitos da violação de Lorentz. Impondo que a componente (kAF)0 seja nula é possível estabelecer soluções estáveis tipo vórtices BPS. O estudo mostra que a influência da violação de Lorentz é manifesta claramente quando o winding number do vórtice é maior que 1.
Andraud, Chantal. "Defauts d'empilement dans le materiau unidimensionnel cscdbr::(3) : etude spectroscopique." Paris 6, 1987. http://www.theses.fr/1987PA066140.
Full textArrieta, Santiago Raul. "Papel do ecocardiograma transesofágico tridimensional na ótima seleção do dispositivo para o tratamento percutâneo da comunicação interatrial tipo ostium secundum." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/98/98131/tde-26042016-083838/.
Full textINTRODUCTION: The ostium secundum atrial septal defect is a congenital heart disease characterized by partial or total deficiency of the fossa ovalis, also known as the septum primum. It corresponds to 10-12% of all congenital heart defects, being the most frequently found in adulthood. Currently, percutaneous closure is the therapeutic method of choice for defects with suitable anatomic features for device implantation in most centers in the world. Bi-dimensional transesophageal echocardiography with color flow mapping is considered the gold-standard tool for anatomic assessment and procedural monitoring, being crucial for optimal device selection. In this regard, a sizing balloon is introduced and inflated across the defect with temporary occlusion. The waist measurement seen on the balloon (stretched diameter) is used as a reference for selection of device size. Recently, real time three-dimensional transesophageal echocardiography has been utilized in this type of percutaneous intervention. In this study we assessed the role of this modality in optimal device selection taking into consideration the dimensions and the geometry of the defect and the thickness of the interatrial septum rims. METHODS: Observational, prospective, non-randomized, single-arm study of a cohort of 33 adults with atrial septal defects submitted to percutaneous closure using a self-centered nitinol device (Cera (TM), Lifetech Scientific, Shenzhen, China). The largest and the smallest diameter of the defect, its area and the measurements of the stretched diameter of the sizing balloon were assessed by both echocardiographic modalities. The defects were considered as elliptical or circular according to their geometry; the rims surrounding the defect were considered thick (> 2 mm) or thin. The selected device was equal to or 2 mm larger than the stretched diameter on bi-dimensional transesophageal echocardiography (gold-standard). In an attempt to identify a variable that could replace the stretched balloon diameter, a series of linear correlations were performed. RESULTS: The mean age and weight were 42.1 ± 14.9 years and 66.0 ± 9.4 kgs, respectively; being 22 of the female gender. There were no statistical differences between the largest and smallest diameters of the defects and the stretched diameters determined by both echocardiographic modalities. The correlation between the measurements obtained by both methods was excellent (r > 0.90). The largest defect diameter obtained by three-dimensional transesophageal echocardiography was the variable that showed the best correlation with the selected device size in the entire group (r= 0.89), especially in the subgroups with elliptical geometry (r= 0.96) and with thick rims surrounding the defect (r=0.96). CONCLUSIONS: In this study in adults with ostium secundum atrial septal defects submitted to percutaneous occlusion with the Cera (TM) device, optimal device selection could be performed using solely the largest diameter of the defect obtained by real time three-dimensional transesophageal echocardiography, especially in patients with elliptical defects and thick rims.
Osman, Ahmad. "Automated evaluation of three dimensional ultrasonic datasets." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00995119.
Full textFong-Lin and 陳豐霖. "The Role of Real-Time Three-Dimensional Echocardiography in Congenital Septal Defects: Assessing and Guiding the Treatment Procedures for Atrial Septal Defect and Ventricular Septal Defect." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/42657016292355927292.
Full text中山醫學大學
醫學研究所
95
Background: Two-dimensional echocardiography (2DE) enhanced by combining with color Doppler technology has significant limitations in providing precise quantitative information, geometric assumptions to calculate chamber volume, mass, and ejection fraction. Reconstructed three-dimensional echocardiographic (3DE) systems (from multiple cross-sectional echocardiographic scans) are still cumbersome and time-consuming. Real-time 3DE (RT3DE) with shorter imaging time than with 3D reconstruction techniques can obtain qualitative and quantitative information on heart disorders. Our purpose was to estimate the patient of Atrial Septal Defect (ASD) and Ventricular Septal Defect (VSD). Transcatheter Amplatzer septal occluder (ASO) device closure of atrial septal defects (ASDs) has traditionally been guided by two-dimensional transesophageal echocardiography (2D-TEE) and intracardiac echocardiography (ICE) modalities. Real-time three-dimensional transthoracic echocardiography (RT3D-TTE) provides rotating images to define ASD and adjacent structures with potential as an alternative to 2D-TEE or ICE for guiding the device closure of ASD. There are two subjects of this study. The first subject was to assess the feasibility and effectiveness of RT3D-TTE in parasternal four-chamber views to guide ASO device closure of ASD. The second subject was to investigate the feasibility and potential value of RT3DE as a means of accurately and quantitatively estimating the size of VSD to correlate with the surgical findings. Materials and Methods: From February 2004 to August 2005, total 97 patients of septal defect were samples. Among in these patients, the 59 patients underwent transcatheter ASO device closure of ASD. The first 30 patients underwent 2D-TEE guidance under general anesthesia and the remaining 29 patients underwent RT3D-TTE guidance with local anesthesia. In addition, the 38 patients with VSD were examined with RT3DE. 3D image data-base was post-processed using TomTec echo 3D workstation. The results were compared with the results measured by 2 DE and surgical findings. Results: The first subject of atrial septal defect patients. All interventions were successfully completed without complications. The clinical characteristics and transcatheter closure variables of RT3D-TTE and 2D-TEE were compared. Echocardiographic visualization of ASD and ASO deployment was found to be adequate when using either methods. Catheterization laboratory time (39.1±5.4 vs 78.8±14.1 minutes, P < 0.001) and interventional procedure length (7.6±4.2 vs 15.3±2.9 minutes, P < 0.001) were shortened by using RT3D-TTE as compared with 2DE-TEE. There was no difference in the rate of closure following either method, assessed after a 6-month follow-up. The maximal diameter measured by RT3D-TTE and 2D-TEE was correlated well with a balloon stretched ASD size (y = 0.985x + 0.628, r = 0.924 vs y = 0.93x + 2.08, r = 0.885, respectively). The second subject of RT3DE produced novel views of VSD and improved quantification of the size of the defect. The sizes obtained from 3DE have equivalent correlation with surgical findings as diameter measured by 2-DE (r = 0.89 vs r = 0.90). Good agreement between blinded observers was achieved by little interobserver variability. Conclusion: RT3D-TTE may be a feasible, safe, and effective alternative to the standard practice of using 2D-TEE to guide ASO deployment. In addition, RT3DE offers intraoperative visualization of VSD to generate a “virtual sense of depth”without extending examining time. From an LV en face projection, the positions, sizes, and shapes of VSDs can be accurately determined to permit quantitative recording of VSD dynamics. It is a potentially valuable clinical tool to provide precise imaging for surgical and catheter-based closure of difficult perimembranous and singular or multiple muscular VSD.
Kochhar, S. S. "Defence mechanisms and personality dimensions." Thesis, 1985. http://hdl.handle.net/2009/4298.
Full textWang, Z. H., and 王政輝. "PROPERTIES OF DEFECT MODES IN ONE-DIMENSIONAL PHOTONIC CRYSTALS." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/07299289598256272535.
Full text國立臺灣師範大學
光電科技研究所
98
In this thesis, we have three topics. The first one is to study the defect modes in the asymmetric and symmetric multilayer narrowband transmission filters in the simple case of normal incidence. It is based on the wavelength-dependent transmittance calculated by making use of the transfer matrix method. In an asymmetric filter, there exists only one defect mode within the photonic band gap and its position can be changed when the design wavelength is varied. In a symmetric filter, it is found that there are two defect modes. Using Bloch wave approximation, these two defect modes respectively correspond to the symmetric and the asymmetric field solutions in the defect layer. The second part is to extend the first part to the oblique incidence for the same structures. The defect modes are investigated by the calculated wavelength-dependent transmittance for both TE and TM waves. The dependences of defect modes on the angle of incidence are illustrated. Additionally, the effect of defect thickness on the number of defect modes is also examined. The third part is to study the angle- and thickness-dependent photonic band structures in a one-dimensional superconducting photonic crystal. It is studied near and below the threshold frequency at which the superconducting material has a zero permittivity. The gap structure is analyzed as a function of the thicknesses of the two constituent superconducting and dielectric materials. In the angular dependence of the band structure, in TM-polarization, there exists a strongly localized superpolariton gap approximately the threshold frequency. This gap is shown to be enhanced as the angle increases.