Academic literature on the topic 'Plane wave lens'

Plane wave generator is normally composed of two explosives having dissimilar detonation velocity. It is used for directing the spherically outgoing shock wave front to a planar form. Plane wave generators are utilized to find material behavior under dynamic loading. This paper presents the shock arrival time for two plane wave generators by developed Matlab code and its comparison with Ansys Autodyn. The diameter of both plane wave generators is kept the same. One plane wave generator is composed of Octogen and Barium Nitrate and the other is composed of Octogen and Tri Nitro Toluene. Obtained results were surprisingly in agreement. Maximum and minimum obtained flatness for the plane wave were ±0.56 and ±0.08ms respectively within the whole diameter of the plane wave generator. The developed code can be utilized to find the profile of a plane wave generator, minimizing the time and cost many times.

Ray diagrams have been calculated for a thermal-wave lens. Focussing is evident provided diffraction effects can be reduced. A practical use of the thermal lens is to scan for defects in a sample material along the focal plane of the lens.

The problem of scattering of a plane electromagnetic wave by a truncated axisymmetric Gutman lens including calculation of the field inside the lens is considered. The problem is solved numerically using the hybrid projection method developed earlier for the general case of wave scattering by inhomogeneous bodies of revolution. New results are presented that demonstrate the accuracy of the method, as well as the field distribution in the Gutman lens, which characterize the features of wave focusing depending on the lens size, focal length, and position of the truncation plane.

A highly accurate method for calculating X-ray propagation is developed. Within this approach, the propagating wave is represented as a superposition of oriented Gaussian beams. The direction of wave propagation in each Gaussian beam agrees with the local direction of propagation of the X-ray wavefront. When calculating the propagation of X-ray waves through lenses, the thin lens approximation is applied. In this approximation, the wave parameters change discontinuously when the wave passes through a lens; the corresponding explicit formulae are derived. The theory is applied to highly accurate calculation of the focusing of X-rays by a system of many beryllium lenses. Fine structure of the wave electric field on the focal plane is revealed and studied. The fine structure is formed due to the diffraction of waves at the edges of the lens apertures. Tools for controlling the calculation accuracy are proposed. The amplitude of the electric field on the focal plane and the focal spot width are shown to be very sensitive to the quality of the calculation, while the best focus position can be obtained even from simple calculations.

The present paper aims to complete an earlier paper where the acoustic world was introduced. This is accomplished by analyzing the interactions which occur between the inhomogeneities of the acoustic medium, which are induced by the acoustic vibrations travelling in the medium. When a wave packet travels in a medium, the medium becomes inhomogeneous. The spherical wave packet behaves like an acoustic spherical lens for the acoustic plane waves. According to the principle of causality, there is an interaction between the wave and plane wave packet. In specific conditions, the wave packet behaves as an acoustic black hole.

Plane wave generator is normally composed of two explosives having dissimilar detonation velocity. It is used for directing the spherically outgoing shock wave front to a planar form. Plane wave generators are utilized to find material behavior under dynamic loading. This paper presents the shock arrival time for two plane wave generators by developed Matlab code and its comparison with Ansys Autodyn. The diameter of both plane wave generators is kept the same. One plane wave generator is composed of Octogen and Barium Nitrate and the other is composed of Octogen and Tri Nitro Toluene. Obtained results were surprisingly in agreement. Maximum and minimum obtained flatness for the plane wave were ±0.56 and ±0.08ms respectively within the whole diameter of the plane wave generator. The developed code can be utilized to find the profile of a plane wave generator, minimizing the time and cost many times.

Abstract Probe formation in scanning electron microscope (SEM) is often reduced to objective lens action modeling based on a point-spread function or Fourier transforms. In this study, we present the first complete wave optical modeling of the whole SEM column based on plane-by-plane propagation of the electron beam wavefunction without simplifying the optical system. We identify the challenges in plane-by-plane beam propagation and show how sampling limitations produce aliased results. Through a careful selection and combination of propagators, we have developed a general wave optical propagation method that is able to overcome the aliasing problem to achieve the appropriate probe widths. Using a two-step propagator, we show that it is possible to model the electron beam distribution throughout the column from the virtual source plane to the specimen plane. We also show that our results from the wave optical simulations are consistent with the geometrical theory of probe formation. Finally, as a direct application of this method, we demonstrated that the combined effect of aberrations in the condenser lens and the probe forming objective lens cannot be accurately represented using only the objective lens. Designing beam shaping experiments and studying the effect of partial coherence can be some novel applications.

For decades, terahertz (THz) microscopic imaging has been limited by the resolution of the system due to the larger wavelength, the power of the source, and the equivalent noise power of the detector, so a lot of research has focused on single-point scanning imaging. With the development of hardware, full-field THz imaging based on high-power continuous-wave THz sources have been developed such as the direct intensity imaging method and lensless coherent imaging. In particular, the THz direct intensity imaging method requires no complicated computational reconstruction, while the high resolution, as a key issue, still needs to be improved. In this paper, the rotating coherent scattering microscopy was applied to THz imaging for the first time. Here, we designed and fabricated a hemisphere lens with high-resistance silicon. The tilted hemisphere lens transformed the incident divergent beam into a plane wave, and the total internal reflection occurred in the planar surface within the hemispherical lens, and generated evanescent waves in the rare medium. At the same time, the sample was placed very close to the plane of the hemispherical lens, so that the sample was illuminated by the evanescent waves. The scattered waves carried high frequency information to the far field, and thus through an objective, the super-resolution imaging was achieved along a single direction. Then, the hemispherical lens was rotated to obtain coherent scattering microscopic images under different evanescent wave illumination angles. Finally, the full-field super-resolution imaging results were obtained through incoherent superposition.

A lens constructed by optimally arranging point-like scatterers on a lattice was proposed according to the Fresnel lens concept and showed superior performance focusing an incident plane wave on a focal point and suppressing the sound field except in the vicinity of the focal point. In the present study, we investigated the transcranial focusing performance of the scatterer-array lens which is a kind of Fresnel acoustic lens. The arrangement of the scatterers was optimized by minimizing an objective function so that the sound field vanishes within the skull except at the focal point(s) and becomes higher at the focal point(s) than in the surrounding area. It was confirmed that the lens focused the incident plane wave with sufficient intensity and contrast with the surroundings, even transcranially.

Terahertz waves can pass through silicon wafer with less loss than traditional lenses. By selecting square, circular and sectors as building blocks, a serial of equivalent lenses for terahertz wave transmission were designed in the vertical plane of the silicon wafer, including hemispherical convex, concave mirror, triangular prism and spherocylinder lenses. The lens’ 2-D design in this work is much simpler than its actual 3-D shape. Besides high transmit ability, silicon wafer also has high refractive index. When a lens is oriented horizontally, it can act as a graded-index photonic crystal waveguide, due to the existence of a band gap, especially for cylinder and prism lens.

Cette thèse étudie les mécanismes de dissipation de marée dans les étoiles de faible masse, possédant comme notre Soleil une enveloppe convective externe (i.e. de types M à F), ainsi que dans les planètes géantes gazeuses similaires à Jupiter et Saturne. En particulier, nous cherchons à comprendre et à caractériser l’influence de la structure et de la dynamique internes de ces corps sur les différents mécanismes physiques à l’origine de cette dissipation afin d’évaluer leur importance relative.Dans le cas des planètes géantes, nous utilisons des modèles semi-analytiques préexistants et nous montrons que la dissipation induite par la présence éventuelle d’un cœur solide viscoélastique n’est pas négligeable par rapport à celle induite par les ondes inertielles (dont la force de rappel est l’accélération de Coriolis) dans l’enveloppe convective. Pour les étoiles de faible masse, nous développons de nouvelles méthodes semi-analytiques ainsi que des simulations numériques d’ondes inertielles de marée se propageant dans l’enveloppe convective externe, dont nous calculons et caractérisons la dissipation d’énergie associée. Pour la première fois, nous prenons en compte les effets d’une rotation différentielle latitudinale telle qu’observée dans le Soleil et prédite par de nombreuses simulations numériques de convection dans les étoiles de faible masse. Nous mettons en évidence l’existence de nouvelles familles de modes inertiels ainsi que l’importance des résonances de corotation pour la dissipation de marée. Enfin, nous dérivons une nouvelle prescription pour la viscosité turbulente appliquée à ces ondes de marées en prenant en compte l’influence de la rotation sur les propriétés de la convection le long de l’évolution des étoiles<br>This thesis studies the tidal dissipation mechanisms in low-mass stars that have an external convective envelope like the Sun (i.e. from M- to F-type stars), as well as in Jupiter- and Saturn-like gaseous giant planets. We particularly focus on understanding and characterizing the influence of the internal structure and dynamics of these bodies on the various physical mechanisms that cause this tidal dissipation, in order to assess their relative strength.In the case of giant planets, we use preexisting semi-analytical models and we show that the dissipation induced by the possible presence of a viscoelastic solid core is not negligible compared to the one induced by inertial waves (whose restoring force is the Coriolis acceleration) in the convective envelope. For low-mass stars, we perform a new semi-analytic study as well as numerical simulations of tidal inertial waves propagating in the external convective envelope, and we compute the associated energy dissipation. For the first time, the effects of a background latitudinal differential rotation, as observed in the Sun and predicted by various numerical simulations of convection in low-mass stars, is taken into account. We highlight the existence of new families of inertial modes as well as the importance of corotation resonances for tidal dissipation. Finally, we derive a new prescription for the turbulent viscosity applied to these tidal waves that takes into account the influence of rotation on the properties of convective flows along the evolution of stars

Ces travaux de thèse concernent la morpho-dynamique d'une plage de poche sableuse, située en environnement macrotidal. L'étude est menée sur la plage de Porsmilin, une plage de type intermédiaire avec une terrasse de basse mer. Cette étude s’appuie sur des observations in situ acquises lors de campagnes de mesures, organisées au cours de cette thèse. Le principal objectif est de caractériser le rôle de la pente, dans l'équilibre dynamique existant entre les processus hydrodynamiques et la morphologie de la plage. La dynamique des niveaux d’eau, de la propagation des ondes infragravitaires et de la turbulence sont examinés et mis en regard des variations morphologiques de la plage, en particulier de la pente locale de la plage. Les niveaux d’eau sont globalement sous-estimés par les formulations empiriques proposées dans la littérature. Des formules adaptées au site de Porsmilin sont présentées. L’impact de la brisure de pente observée le long du profil de plage sur la dynamique de la plage, est étudié. La variabilité de la position de la brisure de pente est impliquée dans les processus d’accommodation à court terme de la plage. Cela se traduit par un retrait vers le haut de plage de la brisure de pente, permettant une dissipation plus efficace de l’énergie incidente par la terrasse de basse mer. En revanche, ce retrait peut conduire, à une concentration d’énergie importante en haut de plage, lors de conditions particulièrement énergétiques, associées à un marnage important. La position de la brisure de pente pourrait être un bon indicateur de l'état de vulnérabilité de la plage face à des évènements énergétiques, ce qui constitue une information primordiale dans le contexte actuel d’érosion généralisée des littoraux sableux<br>This PhD work is focused on the morphodynamic of a pocket beach, located in a macrotidal environment. The beach type is intermediate, with a low tide terrace. The study is based on in situ observations, collected during field campaigns organized during the PhD. The objective is to characterize the beach slope impact on hydrodynamics processes and beach morphology. The water levels dynamic, infragravity waves propagation and turbulence generation in the swash zone, are examined and linked to the beach slope variability.The empirical formulations proposed in the literature show large under-estimations of water levels in the site. Empirical formulations adapted to the beach are proposed.The characteristic break slope presents along the cross-shore profile of low tide terrace beaches is studied. The variability of the break slope location is relevant to explain the short term accommodation of the beach. Under incident wave energy, the location of the beach slope moves shoreward, allowing higher wave dissipation by the low tide terrace. Nevertheless, the reflective part is reduced, which leads to a vulnerable state of the upper beach under strong forcing associated with high tide. The location of the beach slope is found to be a good indicator of the beach vulnerability under a given wave forcing. It provides valuable information in the globalized beach erosion context

The topic of this thesis is about experimental study of phenomena which are associated with light propagation in nonlinear dielectric media. In the first part of this work, we study experimentally the snake instability of the bright soliton stripe of the (2+1)-dimensional hyperbolic nonlinear Schrödinger equation. The instability is observed, through spectral measurements, on spatially extended femtosecond pulses propagating in a normally dispersive self-defocusing semiconductor planar waveguide. The second part of this thesis is about light propagation in nonlinear periodic media. We experimentally observe a stationary spatial gap (or Bragg) soliton in a periodic semiconductor planar waveguide. Based on the interference pattern of the soliton beam, we measure the power parameter of the soliton which is related to the position of the spatial spectrum in the linear band gap. <p><p><p>Cette thèse de doctorat a pour sujet l’étude expérimentale de phénomènes associés à la propagation de la lumière dans les milieux diélectriques non linéaires. La première partie porte sur la démonstration expérimentale de l’instabilité serpentine d’une bande solitonique dans un système décrit par une équation de Schrödinger non linéaire à (2+1)-dimensions. L’instabilité est observée sur base de mesures du spectre spatial ainsi que du profil spatio-fréquentiel d’une impulsion femtoseconde après propagation dans un guide plan semi-conducteur qui présente une dispersion normale et une non-linéarité défocalisante. Le second thème abordé concerne la propagation de la lumière dans les milieux non linéaires périodiques. Les expériences réalisées ont montré l’existence du soliton de Bragg spatial stationnaire sous forme de faisceaux se propageant dans des guides plans semi-conducteurs périodiquement gravés. Sur base du profil de la distribution modale en intensité du faisceau soliton, il a été possible de mesurer le paramètre de puissance du soliton de Bragg qui détermine la position du spectre spatial dans la bande interdite linéaire. <p><br>Doctorat en sciences appliquées<br>info:eu-repo/semantics/nonPublished

Le littoral sableux du Languedoc-Roussillon est un système vulnérable aux risques d'érosion et de submersion. Ces aléas sont liés à la conjonction des facteurs naturels que sont les vagues, vent, élévation du niveau de la mer et apports sédimentaires et sont donc aggravés en période de tempête. En vue d'une gestion des risques, une meilleure connaissance des phénomènes hydrodynamiques de l'échelle littorale à l'échelle côtière est essentielle. Ce travail a conduit à la réalisation d'une plateforme de modélisation numérique composée du modèle de circulation océanique 3D Symphonie, traditionnellement dédié aux échelles régionales et côtières, qui a été modifié pour inclure le forçage par les vagues, modélisées par les modèles Wavewatch III ou Swan, et ainsi étendre sa validité au littoral. Le modèle a été testé sur des cas académiques littoraux. Des mesures sur la plage à double barres de Sète pendant l'hiver 2008-2009, ont également servi à parfaire le modèle qui reproduit ainsi avec succès les caractéristiques des courants en zone littorale : la dérive, les courants sagittaux sur des bathymétries plus complexes et les profils verticaux des courants. Pour valider le modèle à des échelles plus côtières, nous avons confronté ses résultats à des mesures réalisées pendant une tempête hivernale en 2004 aux alentours de l'embouchure de la Têt, mais également sur des tempêtes de 2007 et 2008 dans le Golfe d'Aigues-Mortes. Les courants sont globalement bien reproduits. Les zones d'action des vagues semblent limitées aux zones de profondeur inférieure à 30 m. Notre modèle autorise une reproduction correcte des courants à toutes les échelles et sa nature 3D permet un calcul plus précis de la tension de cisaillement de fond et du courant près du fond, responsables respectivement de la mise en suspension et de l'advection des sédiments.

Au début du 20ème siècle, l'étang de Berre était occupée par de larges prairies sous-marines de Zostera qui ont fortement réduit sous l'impact des pollutions et arrivées massives d'eau douce par le canal EDF. Pollutions et arrivées d'eaux ont beaucoup réduit mais les herbiers ne s'étendent pas vers le large. Cette thèse a donc pour but d'analyser les interactions entre les herbiers sous-marins de l'étang de Berre basé sur l'hypothèse que la dynamique hydro-sédimentaire peut jouer un rôle dans le maintien des herbiers à l'état relique. Dans cette lagune, le vent conditionne l'hydrodynamisme en générant des vagues de vent et des courants.L'atténuation des vagues par l'herbier est en lien avec la hauteur des vagues (dépendant de la vitesse du vent, la longueur de fetch et des effets de réfraction lié à la morphologie de la anse) et est modulée par la biométrie de l'herbier, le niveau d'eau ou la présence de courants. Alors qu'au dessus de l'herbier, les courants sont rapides et fortement influencés par le vent et les vagues de vent, une couche de transition eau-canopée permet la dissipation de l'énergie des vagues et des courants. Dans la canopée, les courants sont très atténués grâce à la présence de l'herbier. L'herbier apparaît comme un élément important de la dynamique sédimentaire car il peut, par sa simple présence, réduire l'hydrodynamisme et modifier l'évolution du fond dans et en arrière de l'herbier et protéger la plage. Le niveau de récurrence de vents forts semble contrôler les évolutions sédimentaires.Les fortes interactions de l'herbier avec la dynamique hydro-sédimentaire laissent penser qu'elle pourrait limiter leur extension dans des zones plus exposées<br>Berre lagoon was occupied by extensive meadows at the turn of the 20th century which regressed down under the impact of urban and industrial pollution and inflow of the EDF canal. Even though freshwater inputs and pollutions were drastically reduced respectively in the 1980s and 1990s, meadows have not significantly gained ground. This thesis aims at analysing the interactions between seagrass meadows of Berre lagoon, hydrodynamics and sedimentary processes, based on the postulate that these mechanisms are important in the maintenance of the meadows in their present dispersed form. In the lagoon, winds constitute the dominant influence on hydrodynamics in the lagoon by generating wind waves and currents. Wave attenuation is linked to wave height, which is, in turn, dependent on wind intensity and fetch length and modified by the bay morphology. Wave attenuation is also modulated by meadow biometry, and by water levels and currents.Whereas currents are strong and strongly influenced by wind and wind waves above the meadow, a transition canopy-water layer dissipates waves and currents. In the canopy, currents are thus attenuated.The meadow is not just a passive element in the overall sediment dynamics since it reduces energy and thus modifies substrate changes within and in the back of the meadow, thus protecting the shoreline. However, it is the recurrence of strong wind that seems to drive sedimentary changes. The strong interactions between the meadow and the hydrodynamic and sedimentary processes could limit the extension of the meadow in areas more exposed to waves

L'objectif de cette thèse est de contribuer à la compréhension des enjeux de l'épargne salariale pour les politiques de rémunérations dans les entreprises en France. Une mise en perspective historique et théorique permet d'abord d'identifier les motivations conduisant les entreprises à développer un dispositif alliant l'intéressement et le PEE. Ensuite, nous explicitons à travers une modélisation théorique de type « Principal-Agent » les caractéristiques d'un contrat associant l'intéressement à un PEE. Les prédictions théoriques qui en découlent sont enfin validées par une étude empirique sur des données individuelles d'entreprises et de salariés. A partir d'une estimation par appariement sur le score de propension, les résultats révèlent que les entreprises qui intègrent à leurs politiques de rémunérations un dispositif alliant l'intéressement et le PEE versent en moyenne des salaires de base plus faibles, compensés par le versement d'une prime d'intéressement. Par ailleurs, celui-ci s'accompagne d'un impact positif et significatif sur le profit mais d'un effet non significatif sur la productivité du travail des entreprises. Il existe néanmoins une corrélation positive entre la mise en œuvre du dispositif et la productivité du travail pouvant avoir pour origine un effet de sélection. Ces travaux nous invitent à défendre la thèse selon laquelle l'instauration par les entreprises d'un dispositif alliant le partage du profit et le PEE vise non seulement des effets d'incitation mais aussi des objectifs de maîtrise des coûts salariaux. Au-delà, lorsque le PEE donne lieu à la constitution de l'actionnariat salarié, il permet aux entreprises de poursuivre des objectifs de stabilisation du capital<br>This dissertation aims at shedding a new light on the analysis of the effects of profit sharing and employee ownership plan on wages practices in France. We firstly purpose a survey of the theoretical foundations of profit sharing and employee ownership plan. By considering institutional and macroeconomic changes in France since 1980, we secondly develop an historical analysis of the financial participation. In this context, we argue that a system based on both profit sharing and employee ownership plan is not only designed as an effort incentive scheme but also as a risk transfer device. We thirdly develop a Principal-Agent model to determine the optimal characteristics of a contract based on both profit sharing and employee ownership plan. Our hypothesis is then tested on an original matched employer-employee database concerning French firms. Using a Propensity Score Matching method which allows controlling for potential selection bias, we show that such a contract has no significant impact on the labour productivity but a positive one on the firm's benefit. We finally find a negative impact on the employee's base wage but no significant effect on the total earnings

This thesis presents research towards enabling micromachined millimeter and submillimeter wave focal plane arrays (FPAs). The FPAs operate under the following principle: a switch network consisting of microelectromechanical (MEMS) switches, integrated with micromachined waveguides, is used to feed an array of antenna elements, located in the focal plane of a high-gain quasi-optical system. Hence, it is possible to switch between a set of narrow beams in different directions. Such beam steering systems are needed for future millimeter and submillimeter wave imaging and communication systems. The contributions to future MEMS-switchable FPAs presented here are organized in three papers, as described below. Paper I presents a criterion on the spacing between adjacent FPA elements which results in -3 dB overlap between the switched beams, for the special case when an extended hemispherical dielectric lens is used as the optical system. A key step towards this criterion is a closed-form relation between the scan angle and the FPA element's position, which results in an expression for the effective focal length of extended hemispherical lenses. A comparison with full-wave simulations demonstrates an excellent agreement with the presented theoretical results. Finally, it is shown that the maximum feasible FPA spacing when using an extended hemispherical lens is about 0.7 wavelengths. Paper II presents a numerical study of silicon-micromachined planar extended hemispherical lenses, with up to three matching regions used to reduce internal reflections. The effective permittivity of the matching regions is tailor-made by etching periodic holes in the silicon wafer. The optimal thickness and permittivity of the matching regions were determined using TRF optimization, in order to yield the maximum wide-band aperture efficiency and small side-lobes. We introduce a new matching region geometry, referred to as shifted-type matching regions, and it is demonstrated that using three shifted-type matching regions results in twice as large aperture efficiency as compared to using three conventional concentric-type matching regions. Paper III presents a submillimeter-wave single-pole single-throw (SPST) 500-750 GHz MEMS waveguide switch, based on a MEMS-reconfigurable surface inserted between two waveguide flanges. A detailed design parameter study is carried out to select the best combination of the number of horizontal bars and vertical columns of the MEMS-reconfigurable surface, for achieving a low insertion loss in the transmissive state and a high isolation in the blocking state. A method is presented to model the non-ideal electrical contacts between the vertical cantilevers of the MEMS surface, with an excellent agreement between the simulated and measured isolation. It is shown that the isolation can be improved by replacing an ohmic contact by a new, capacitive contact. The measured isolation of the switch prototype is better than 19 dB and the measured insertion loss is between 2.5 and 3 dB.<br>Denna avhandling presenterar forskning som syftar till att möjliggöra fokalplans-gruppantenner (FPAs) för våglängder i millimeter och submillimeterområdet. Principen för en sådan FPAs funktion är följande: ett nätverk bestående av mikroelektromekaniska (MEMS) switchar, används för att välja mellan de olika antenn-elementen i en gruppantenn, som placerats i fokalplanet av ett optiskt system. Därmed blir det möjligt att välja från en uppsättning av smala lober i olika riktningar. Sådana lob-styrningssystem behövs för framtida radar- och kommunikationssystem i millimeter och submillimeterområdet. Resultaten är uppdelade i tre vetenskapliga artiklar, som beskrivs nedan. I den första artikeln (Paper I) presenteras ett villkor för avståndet mellan närliggande FPA-element som resulterar i -3 dB överlappning mellan de switchade loberna, för specialfallet då en förlängd hemisfärisk lins används som optiskt system. Det viktigaste steget mot att hitta detta villkor är att bestämma en analytisk relation mellan avsökningsvinkeln och FPA-elementens position. Detta resulterar i ett uttryck för den effektiva fokallängden för denna typ av lins. En utmärkt överensstämelse har funnits mellan dessa relationer och simuleringar. Slutligen visas det att de största möjliga FPA-avstånden för en förlängd hemisfärisk lins är ungefär 0.7 våglängder, vilket uppnås för linser med låg permittivitet. I den andra artikeln (Paper II) presenteras en numerisk studie av plana förlängda hemisfäriska linser, som kan produceras från en kiselskiva. Linserna har upp till tre matchningsregioner, som används för att reducera interna reflektioner. Den effektiva permittiviteten av de matchande regionerna skräddarsys genom etsning av periodiska hål i kiselskivan. Den optimala tjockleken och permittiviteten av de matchande regionerna har bestämts med hjälp av TRF-optimering, för att ge maximal bredbandig direktivitet och minimala sidlober. En ny geometri introduceras för matchningsregionerna, som vi kallar matchningsregioner av skiftad typ. Vi visar att användning av tre matchningsregioner av skiftad typ resulterar i en dubbelt så hög apertur-effektivitet, jämfört med att använda tre konventionella matchningsregioner av koncentrisk typ. I den tredje artikeln (Paper III) presenteras en MEMS-switch för rektangulära vågledare, för frekvensområdet 500-750 GHz. Baserat på en designparameterstudie har den bästa kombinationen av antalet horisontella rader och vertikala kolumner hos den MEMS-konfigurerbara ytan valts ut, för att uppnå låga förluster i det öppna tillståndet och hög isolation i det blockerande tillståndet. I artikeln presenteras en metod för att modellera icke-perfekta elektriska kontakter mellan de fixerade och de rörliga delarna i MEMS-ytan. Denna metod uppvisar en utmärkt överensstämmelse mellan den simulerade och den uppmätta isolationen. Vi visara att isolationen kan förbättras med hjälp av en ny typ av kapacitiv kontakt. Den uppmätta isolationen hos den presenterade switch-prototypen är högre än 19 dB, och den uppmätta förlusten är mellan 2.5 och 3 dB.<br><p>QC 20161206</p>

碩士<br>國立交通大學<br>電信工程研究所<br>106<br>In this thesis, a low cost Fresnel Zone Plate lens antenna was designed, fabricated and measured. The antenna under consideration consists of a horn antenna for generating the spherical wave front, and a Fresnel Zone Plate lens for converting the spherical wave front into the plane wave in far field. Specifically, such a class of Fresnel Zone structures was implemented on a low-cost dielectric substrate, FR4, which is commonly used in microwave region. Different from the guided-wave structure, the wave is scattering, which includes the transmission and reflection, by the thin dielectric slab rather than propagating within it; thus, the energy absorbed by the lossy dielectric is relatively less significant. Additionally, the free-standing dielectric slab is a Fabry-Perot-like structure, the dielectric thickness has to be properly chosen to obtain maximum transmission in the operation frequency bandwidth. Furthermore, the offset Fresnel Zone Plate lens was also developed to have the main-beam radiate toward an offset angle. This author has implemented several deformed Fresnel Zone plate lenses for observing the offset radiation main-beam angles; the agreement between the measured and simulated results, in general, is good.

碩士<br>國立臺灣海洋大學<br>河海工程學系<br>93<br>This thesis investigates the diffraction of a lens-shaped cavity subjected to plane SH-waves by using the field-matching method. In solution procedures, we regard the major axis of a cavity as the circular diameter to set the circular auxiliary boundary at first. Then, the entire domain could be divided into three sub-regions. In each coordinate system of sub-regions, the displacement could be expressed in terms of wave functions satisfying the Helmholtz equation and the traction free boundary condition. The local coordinate systems of two neighboring sub-regions are converted into the same coordinate systems by utilizing coordinate transformation formulas. After applying the collocation method to constitute simultaneous equations at the auxiliary boundary, the unknown coefficients of series of wave functions in each sub-region could be determined. Two cross-section shapes of lens-shaped cavities (with equal and unequal radii of curvature) have been calculated in this thesis. The numerical results are presented to illustrate the effects of various incident angles and dimensionless frequencies on the displacement amplitudes and the dynamic stress concentration factors of lens-shaped cavities. It is shown that all computational solutions match very well with the boundary element solutions, and so the correctness of the proposed method is confirmed. According to the numerical results in this thesis, it is shown that the displacement amplitudes on the upstream face of cavities have greater values than those on the downstream face for normal incidence. In the case of equal radii of curvature of lens-shaped cavities, the dynamic stress concentration factors at the tips of cavities reach a relative maximum for the non-horizontal incident waves. This result is due to the fact that the stress singularities at the tips of cavities. However, as the plane SH-waves at horizontal incidence, the dynamic stress concentration factors almost vanish at the tips of cavities. This is due to the equal displacement amplitudes on both sides of the tips of cavities.

Stepping Westward is the first book of its kind dedicated to the literature of the Scottish Highland tour 1720-1830, a major cultural phenomenon that attracted writers and artists like Pennant, Johnson and Boswell, William and Dorothy Wordsworth, Coleridge, Scott, Hogg, Keats, Daniell, and Turner, as well as numerous less celebrated travellers and tourists. Addressing more than a century’s worth of literary and visual representations of the Highlands, the book casts new light on how the tour developed a modern literature of place, acting as a catalyst for thinking about improvement, landscape, and the shaping of British, Scottish and Gaelic identities. Attention is paid to the relationship between travellers and the native Gaels, whose world was plunged into crisis by rapid and forced social change. At the book’s core lie the best-selling tours of Pennant and Dr Johnson, associated with attempts to ’improve’ the intractable Gaidhealtachd in the wake of Culloden. Alongside the Ossian craze and Gilpin’s picturesque, their books stimulated a wave of ’home tours’ from the 1770s through the romantic period, including writing by women like Sarah Murray and Dorothy Wordsworth. The incidence of published Highland Tours (many lavishly illustrated), peaked around 1800, but as the genre reached exhaustion, the ’romantic Highlands’ were reinvented in Scott’s poems and novels, coinciding with steam boats and mass tourism, but also rack-renting, sheep clearance and emigration.

This book explores how Russian writers from the mid-1920s on have read and responded to Joyce's work. The book uncovers the many roles Joyce has occupied in Russia over the last century, demonstrating how the writers Yury Olesha, Vladimir Nabokov, Andrei Bitov, Sasha Sokolov, and Mikhail Shishkin draw from Joyce's texts, particularly Ulysses and Finnegans Wake, to address the volatile questions of lineages in their respective Soviet, émigré, and post-Soviet contexts. Interviews with contemporary Russian writers, critics, and readers of Joyce extend the conversation to the present day, showing how the debates regarding the Irish writer's place in the Russian pantheon are no less settled one hundred years after Ulysses. The creative reworkings, or “translations,” of Joycean themes, ideas, characters, plots, and styles made by the five writers that the book examines speak to shifting cultural norms, understandings of intertextuality, and the polarity between Russia and the West. The book illuminates how Russian writers have used Joyce's ideas as a critical lens to shape, prod, and constantly redefine their own place in literary history. The book offers one overarching approach to the general narrative of Joyce's reception in Russian literature. While each of the writers examined responded to Joyce in an individual manner, the sum of their methods reveals common concerns. This subject raises the issue of cultural values and, more importantly, how they changed throughout the twentieth century in the Soviet Union, Russian emigration, and the post-Soviet Russian environment.

Sustainable development is among the foremost ideas that guide societal aspirations around the world. This book interrogates the concept through a critical lens, examining both its history and the trajectory of its manifestations in the Brazilian Amazon. The book argues that sustainable development is a concept that is better understood as involving embroilments and ongoing processes of contestation rather than a single end goal. The research offers historical analysis of Amazonian development from the colonial era into the discourse and praxis of sustainable development in contemporary times, and then illustrates the tensions of sustainable development plans that are experienced by people living in the areas geographically the closest to where those plans are being implemented. The history of the Brazilian Amazon is introduced to readers through focused discussions on the tensions between making grand plans for the region and the everyday practices and experiences of sustainable development, which involve considerably more muddling. Case studies explore agrarian reform initiatives that occur alongside road paving projects, the creation of extractive reserves and conservation areas that follow in the wake of assassinations, and the construction of a massive hydroelectric dam. While Amazonian sustainable development is a widely-accepted imperative, the research presented here shows how land use and infrastructure plans conducted in the name of sustainable development often perpetuate and reinforce economic and political inequalities.

Abstract Throughout the eighteenth century, independent Indigenous people from the borderlands of the Philippines visited the centers of Spanish colonial rule in the archipelago. Their travels are the counternarratives to one-dimensional stories of Spanish conquest of, and Indigenous resistance in, interior frontiers. Indigenous inhabitants on the island of Luzon constantly moved about—visiting allies and launching raids—and thus shaped history in the process. Their mobility allows us to glimpse their agency in colonial interactions in the early modern period. The landscape contains the traces of how they moved as well as how they channeled and impeded mobility in the borderlands. Mark Dizon views the colonial interactions in Philippine borderlands through the lens of reciprocal mobilities. Spanish mobilities of conquests and conversions had their counterpart in Indigenous visits and ambushes. Colonial encounters were not isolated individual events but rather a connected web of approaches, rebuffs, rapprochements, and dispersals. They took place not only in the exploration of remote forests and mountains but also in conjunction with Indigenous travels to colonial cities like Manila. Indigenous people of the borderlands were not immobile, timeless actors; they created history in their wake as they journeyed through the borderlands and beyond.

This chapter compares the gender dynamics of the Great Depression of the 1930s with those of the Great Recession associated with the 2008 financial crisis. It begins with a discussion of the relationship between gender and unemployment, and between gender and family dynamics during the economic crises. It then examines the family wage and married women's employment in the 1930s as well as inequality among women during the Great Recession. Despite the many changes in gender relations that unfolded in the intervening decades, the chapter shows that the structural effects of the two economic downturns were similar. In both cases, female unemployment increased less, and later, than male unemployment, and birth, marriage, and divorce rates declined as well. The Great Depression spurred a political transformation that led to a sharp reduction in economic inequality, accompanied by a dramatic upsurge in union organizing. Neither of these developments took place after the 2008 crisis. Instead, inequalities between the haves and have-nots have continued to widen, and especially class inequality among women.

As we write these words, the COVID-19 pandemic has become part of our lives in a much more controlled way. For instance, some of our habits have changed and we are able to resume our activities in the way of a “new normal,” returning to social contact with family, friends, and colleagues. In returning to a life without the constraint of the virus at such a high level, the academy tries to resume its rituals, including scholarly events. Email boxes and physical boards at universities are once again filling up with calls for submission of abstracts for congresses, seminars, and workshops. As these events are happening again, academia seems to be reflecting on the pros and cons of onsite scientific events. While acknowledging the importance of such scientific events and their potential for strengthening scholarly communities and collaborations, many academics have begun questioning the real impact of being physically present. This questioning seems to be based on several factors. On the one hand, it is clear that universities have been increasingly devaluing academics’ presence in congresses (unless by invitation). They allocate less funding for these activities, especially for those academics who wish to attend an event without presentation. With no presentation, institutions devalue attendance in performance appraisal processes. Increasingly, academic institutions value publications (indexed, despite some positive movement seeking to counter the tyranny of the “publish or perish” motto), and an academics ability to raise funding. Yet, not all congresses are associated with publication processes in indexed journals or proceedings. Books of abstracts (once edited by any congress) are almost extinct, namely because of their devaluation by institutes of higher learning (and funding entities). On the other hand, the massive and necessary use of online scientific events in 2020 and 2021 allowed us to realize that it is possible, efficient, and effective to hold these events in a format different from the traditional one. The internet offers versatility and more and more congresses are now offered online or in hybrid formats. These formats allow academics to overcome financial and physical complications caused by in-person scholarly events. Academics can request less funding and, at the same time, mitigate concerns of acceptance without presentations, covering classes while away, or having to supplement university sponsorship with personal funds. At some universities, funding comes after attendance regardless of availability of those funds and academics are asked to pay registration fee, plane tickets, and lodging with the expectation of being reimbursed upon return. This is particularly challenging given the present economic situation around the globe. At the same time, while physically at the event and away from families, work continues to accumulate for academics. They then must wade through this excess upon returning home, adding to an already excessive workload. This makes maintaining a work-life balance challenging. We at New Trends in Qualitative Research (NTQR) believe it is particularly relevant to discuss this topic within the context of the release of NTQR Volume 11. NTQR is an indexed journal associated with international scientific events in the field of qualitative research - Congreso Ibero-Americano en Investigación Cualitativa (CIAIQ) and the World Conference on Qualitative Research (WCQR). Specifically, the volume that we edit here aggregates works that, having been originally presented at WCQR2022 (held in an online format), went through a double-blind review process. This volume, annually edited (as WCQR is an annual event), allows us, as editors, to condense a diverse set of qualitative research work, focusing on different topics, and with different methodological designs. And, our concern as editors has always been to assure the quality of the published works, namely through a careful review and editing process. We do not know if we are ready to give up our physical presence at scientific events. But, with opportunities such as online presentations and online publishing venues, we may now be much more judicious in this presence. We may now take time to ponder the relevance of investing in attending a scientific event, and selecting (hand-drawn) two or three events per year, at most. WCQR has a strong emphasis in the building of a scientific community (in this case, bonded by the interest in qualitative research), reconciling physical and online presence, and is associated with quality journals. These aspects help academics to select it as one of the events where it is important to be present. Sincerely, The Editors

AbstractThis study presents the effect of four different turbulent models of solver on the aerodynamic analysis of a shroud at wind speed below 6 m/s. The converting shroud uses a combination of a cylindrical case and an inverted circular wing base which captures the wind from a 360° direction. The CFD models used are: the SST (Menter) k-ω model, the Reynolds Stress Transport (RST) model, the Improved Delay Detached Eddies Simulation model (IDDES) SST k-ω model and the Large Eddies Simulation Wall Adaptive model. It was found that all models have predicted a convergent surface pressure. The RST, the IDDES and the WALE LES are the only models which have well described regions of pressure gradient. They have all predicted a pressure difference between the planes (1–5) which shows a movement of the air from the lower plane 1 (inlet) to the higher plane 5 (outlet). The RST and IDDES have predicted better vorticities on the plane 1 (inlet). It was also found that the model RST, IDDES, and WALE LES have captured properly the area of turbulences across the internal region of the case. All models have predicted the point of flow separation. They have also revealed that the IDDES and the WALE LES can capture and model the wake eddies at different planes. Thus, they are the most appropriate for such simulation although demanding in computational power. The movement of air predicted by almost all models could be used to drive a turbine.

AbstractThe energy budget of the internal tide and its life cycle is investigated with a high resolution numerical simulation and a vertical normal mode decomposition. Two areas of interest are considered: the Azores Islands over the mid Atlantic ridge and the Gulf Stream offshore the North of the US East coast shelf break. Low mode (1 and 2) internal tides are found to propagate from 100 km (mode 2) to 1000 km (mode 1) away from their generation sites. Waves loose a significant portion of their energy as they propagate through the Gulf Stream, in contrast to the Azores domain. In the Gulf Stream domain, the mesoscale circulation is responsible for energy transfers from low to high modes internal tides, while the topographic scattering is dominant in the Azores area. This transfer of energy toward high modes favours energy dissipation. The mesoscale is significant in the energy budget of modes higher than mode 1 for both domains, and for all baroclinic modes in the Gulf Stream area. The internal tide is found to extract or loose energy toward the mesoscale circulation, but this accounts for less than 14%, of the energy scattered from low internal tide modes to higher ones once summed over all contributions of the modal energy budget.

Dans l’histoire de la Normandie médiévale telle qu’elle est présentée aujourd’hui, la bataille de Valesdunes tient une place de premier choix. Il est pourtant légitime de s’interroger sur la place qu’il convient de lui accorder. Le récit le plus circonstancié qui nous soit parvenu est celui de Wace, en langue vernaculaire et dans la deuxième moitié du XIIe siècle. Plusieurs points posent question : l’originalité de ce texte par rapport à ceux qui l’ont précédé ; les impératifs politiques qui ont prévalu à sa rédaction ; la dimension littéraire, poétique, et le rapport qu’elle entretient avec l’exactitude des faits, la dimension historiographique… C’est à ces interrogations que la présente contribution tente d’apporter quelques réponses.

L’étude porte sur 59 individus ou familles de la noblesse laïque et francophone, entre 1300 et 1520 (à l’exclusion des princes). Ils ont apprécié le Lancelot Graal, et le Tristan en prose, et en milieu bourguignon, la tradition historique issue de Geoffroy de Monmouth et Wace. Le Guiron est en retrait. Quant à Chrétien c’est surtout Le Conte du Graal qui est présent dans les bibliothèques. Les romans tardifs, comme Perceforest, Artus ou le Chevalier au Papegau sont plus rares, mais figurent parmi les ouvrages possédés par le cercle des bibliophiles bourguignons. L’examen de deux cas (les Rohan et Bernard de Béarn) permet de relativiser la place de la matière arthurienne dans les bibliothèques nobiliaires. Si le goût pour cette littérature s’est maintenu et a pu prendre une dimension patrimoniale, c’est surtout la noblesse combattante, de cour et de service, qui s’identifie le plus intimement à elle.

In Chapter 2, M. Hamdi-Cherif, P. Malliet, F. Reynes, M. Plane, F. Saraceno, and A. Tourbah argue that public investment in France has been on a downward trend since 2009, rebounding only in the wake of the COVID-19 crisis, with the objective of supporting global demand and spurring economic growth. The increase in investment, however, is less pronounced than during the global financial crisis. Orienting investment towards low-carbon capital within the framework of a long-term emission reduction goal, despite being unprecedented in history, is also insufficient, especially if its level is not maintained over the coming decades. The type of low-carbon transition strategy chosen—either relying more on technological progress or reaching a significant reduction in energy consumption (a Sobriety scenario)—will noticeably impact the composition and amount of investment needed to meet the targets.

AbstractThis chapter introduces central tenets of relational thinking in economic geography and then develops a relational approach for analysing labour control regimes and union agency in GPNs. It conceptualises place-specific labour control regimes at specific nodes of a GPN as emerging from the articulation of six horizontal (i.e. territorially embedded) and vertical (i.e. network embedded) processual relations: the labour process and workplace, wage, labour market, employment and industrial relations at the horizontal dimension, which in turn intersect with sourcing relations at the vertical, ‘network’ dimension of the GPN. Moreover, it develops a relational heuristic framework for analysing union agency in GPNs through the lens of three interrelated spaces of labour agency that unions construct through practices of building relations: (1) spaces of organising comprising internal union relations as well as unions organising practices; (2) spaces of collaboration constructed by unions through building relationships of collaboration with other labour and non-labour actors at various levels; and (3) spaces of contestation constructed by unions around specific labour struggles through building antagonistic relationships with employers, lead firms and state actors as well as through practices of drawing other allied actors into spaces of contestation to activate moral power resources.

Moorcroft’s reputation as a designer continued to grow in these years. His newly launched SunRay tea ware attracted the attention of the influential Council for Art and Industry, and was selected for exhibition both at home and abroad as a model of progressive design. But Moorcroft was openly critical of what he saw as the CAI’s narrow appreciation of his work. He asserted his independence in a letter to The Times, criticising the CAI’s selection criteria for the British display at the International Exhibition of Art and Technology in Paris, 1937, and provocatively exhibited his own selection of decorative pieces in the International Pavilion. His exhibit inspired an article in La Revue moderne which identified in his work a timeless moral value, a particularly significant response at a time when culture was becoming increasingly politicised in Europe. Not coincidentally, he publicised the prominent display of his work in the culturally tolerant Deutsches Museum in Munich, a gesture all the more eloquent as politically motivated exhibitions of National Socialist and of Degenerate Art were taking place less than a mile away at just this time. Moorcroft’s work was appreciated for what one critic called its ‘real truth’; his international reputation as a ceramic artist had never been higher. This double success as designer and artist was unparalleled at a time when the gulf between industrial and studio production was at its deepest. And it doubtless inspired Blackie to invite Moorcroft to write a book on his work; it would have followed publications by two of the most influential potters and instructors of the time, Gordon Forsyth and Dora Billington, who had each recently examined from different perspectives the future relationship of studio pottery and industrial design. The project, though, was barely begun, and only jottings survive which sketch out some of his guiding principles, not least his commitment to integrity in design. Moorcroft’s exhibition at the New York World’s Fair of 1939 again drew the attention of the national press. Ledgers indicate that his sales income was also steadily rising, although not by enough to completely offset the relentless increase in costs. The declaration of war would bring its own problems.

A millimeter-wave (mmW) interferometric phase transmitarray for the multiple-input multiple-output (MIMO) system is proposed, and its phase distribution is the interference superposition of electromagnetic waves radiated by two patch antennas at different locations. Its characteristic is that when multiple EM waves illuminate the center of the array, the transmitted waves are formed into high-directivity beams. In addition, when the plane wave illuminates the interference phase transmitarray vertically, the transmissive plane wave will be scattered and focused to two different positions. A novel MIMO system can be implemented based on the above two characteristics. Compared with the conventional lens MIMO, the advantage of the MIMO system integrated by the interferometric phase transmitarray is that multiple antennas can share one transmitarray, which is beneficial to the miniaturization of the MIMO transceiver. More critically, all channels can efficiently transmit information and increase channel capacity.

In this paper, we explore structure-borne elastic wave energy harvesting, both numerically and experimentally, by exploiting a Gradient-Index Phononic Crystal Lens (GRIN-PCL) structure. The proposed GRIN-PCL is formed by an array of blind holes with different diameters on an aluminum plate where the orientation and size of the blind holes are tailored to obtain a hyperbolic secant gradient distribution of refractive index guided by finite-element simulations of the lowest asymmetric mode Lamb wave band diagrams. Under plane wave excitation from a line source, experimentally measured wave field successfully validates the numerical simulation of wave focusing within the GRIN-PCL domain. A piezoelectric energy harvester disk located at the first focus of the GRIN-PCL yields an order of magnitude larger power output as compared to the baseline case of energy harvesting without the GRIN-PCL on the uniform plate counterpart for the same incident plane wave excitation. The power output is further improved by a factor of five using complex electrical load impedance matching through resistive-inductive loading as compared to purely resistive loading case.

Optical systems are primarily designed and analyzed by tracing bundles of rays. These rays are actually discrete points on the geometrical wavefront propagating through the system. The local field amplitude is inversely proportional to the radius of curvature of the wavefront or the distance from a neighboring ray point. Since by definition diffraction effects are excluded from geometrical optics, the energy density is infinite at focus or, in general, on a caustic. These singularities can be removed if the rays are expanded into physical-optics beamlets which are solutions to at least the reduced (paraxial or parabolic) wave equation. The individual fields would then be finite and continuous everywhere, and their superposition would represent the cumulative effects of aberrations, interference, obscurations, and diffraction in the system. This "fattening" of the infinitesimal geometrical rays is analogous to "thinning" the infinite plane waves used in the Fourier transform solutions of physical optics.

Gradient-index (GRIN) lenses with spherical surfaces are able to yield the equivalent aspherical effects. A refractive system that consists of one plano-concave lens and one convex-piano lens using axial gradient-index materials has been designed to transform a Gaussian beam profile into a uniform intensity distribution. The GRIN distribution in the axial direction and the vertex curvatures of two spherical surfaces are determined by using the energy conservation condition and the condition of constant optical path length, which permits an exiting plane wave. The design and analysis of this gradient-index laser beam reshaping system will be presented and compared with a similar system1 utilizing two aspherical lenses with normal index materials.

Drawing upon longitudinal data from the Growing Up in New Zealand (GUiNZ) study, this research looks at the barriers to mothers leaving partners who use violence. The persistence of conflict or abuse experienced by mothers over the antenatal to 9-month period, and over the 54-month to 8-year period was examined. For these two periods, the association between intimate partner violence (IPV) at the start of the period and the relationship breaking up during this period was explored. Key findings include: * mothers with fewer financial resources are less able to leave partners who use violence. This suggests a lack of financial resources is a barrier to victims of IPV becoming safe. * younger mothers, mothers who lack access to a car, mothers with poor physical health, mothers who are not part of a community, mothers who place high importance on maintaining cultural traditions (who are largely non-Europeans), and mothers whose partners have low education or earnings may also be less able to leave partners who use violence. * consistent with previous studies, this study finds within-relationship conflict and IPV are commonly experienced by New Zealand mothers. * mothers who report conflict or IPV in one survey wave are quite likely to report it again in the following survey wave (one to several years later). However, a considerable proportion of such mothers report no IPV in the following wave, either because their partners stopped using violence or their relationship ended.

1.1 Macroeconomic summary Economic recovery has consistently outperformed the technical staff’s expectations following a steep decline in activity in the second quarter of 2020. At the same time, total and core inflation rates have fallen and remain at low levels, suggesting that a significant element of the reactivation of Colombia’s economy has been related to recovery in potential GDP. This would support the technical staff’s diagnosis of weak aggregate demand and ample excess capacity. The most recently available data on 2020 growth suggests a contraction in economic activity of 6.8%, lower than estimates from January’s Monetary Policy Report (-7.2%). High-frequency indicators suggest that economic performance was significantly more dynamic than expected in January, despite mobility restrictions and quarantine measures. This has also come amid declines in total and core inflation, the latter of which was below January projections if controlling for certain relative price changes. This suggests that the unexpected strength of recent growth contains elements of demand, and that excess capacity, while significant, could be lower than previously estimated. Nevertheless, uncertainty over the measurement of excess capacity continues to be unusually high and marked both by variations in the way different economic sectors and spending components have been affected by the pandemic, and by uneven price behavior. The size of excess capacity, and in particular the evolution of the pandemic in forthcoming quarters, constitute substantial risks to the macroeconomic forecast presented in this report. Despite the unexpected strength of the recovery, the technical staff continues to project ample excess capacity that is expected to remain on the forecast horizon, alongside core inflation that will likely remain below the target. Domestic demand remains below 2019 levels amid unusually significant uncertainty over the size of excess capacity in the economy. High national unemployment (14.6% for February 2021) reflects a loose labor market, while observed total and core inflation continue to be below 2%. Inflationary pressures from the exchange rate are expected to continue to be low, with relatively little pass-through on inflation. This would be compatible with a negative output gap. Excess productive capacity and the expectation of core inflation below the 3% target on the forecast horizon provide a basis for an expansive monetary policy posture. The technical staff’s assessment of certain shocks and their expected effects on the economy, as well as the presence of several sources of uncertainty and related assumptions about their potential macroeconomic impacts, remain a feature of this report. The coronavirus pandemic, in particular, continues to affect the public health environment, and the reopening of Colombia’s economy remains incomplete. The technical staff’s assessment is that the COVID-19 shock has affected both aggregate demand and supply, but that the impact on demand has been deeper and more persistent. Given this persistence, the central forecast accounts for a gradual tightening of the output gap in the absence of new waves of contagion, and as vaccination campaigns progress. The central forecast continues to include an expected increase of total and core inflation rates in the second quarter of 2021, alongside the lapse of the temporary price relief measures put in place in 2020. Additional COVID-19 outbreaks (of uncertain duration and intensity) represent a significant risk factor that could affect these projections. Additionally, the forecast continues to include an upward trend in sovereign risk premiums, reflected by higher levels of public debt that in the wake of the pandemic are likely to persist on the forecast horizon, even in the context of a fiscal adjustment. At the same time, the projection accounts for the shortterm effects on private domestic demand from a fiscal adjustment along the lines of the one currently being proposed by the national government. This would be compatible with a gradual recovery of private domestic demand in 2022. The size and characteristics of the fiscal adjustment that is ultimately implemented, as well as the corresponding market response, represent another source of forecast uncertainty. Newly available information offers evidence of the potential for significant changes to the macroeconomic scenario, though without altering the general diagnosis described above. The most recent data on inflation, growth, fiscal policy, and international financial conditions suggests a more dynamic economy than previously expected. However, a third wave of the pandemic has delayed the re-opening of Colombia’s economy and brought with it a deceleration in economic activity. Detailed descriptions of these considerations and subsequent changes to the macroeconomic forecast are presented below. The expected annual decline in GDP (-0.3%) in the first quarter of 2021 appears to have been less pronounced than projected in January (-4.8%). Partial closures in January to address a second wave of COVID-19 appear to have had a less significant negative impact on the economy than previously estimated. This is reflected in figures related to mobility, energy demand, industry and retail sales, foreign trade, commercial transactions from selected banks, and the national statistics agency’s (DANE) economic tracking indicator (ISE). Output is now expected to have declined annually in the first quarter by 0.3%. Private consumption likely continued to recover, registering levels somewhat above those from the previous year, while public consumption likely increased significantly. While a recovery in investment in both housing and in other buildings and structures is expected, overall investment levels in this case likely continued to be low, and gross fixed capital formation is expected to continue to show significant annual declines. Imports likely recovered to again outpace exports, though both are expected to register significant annual declines. Economic activity that outpaced projections, an increase in oil prices and other export products, and an expected increase in public spending this year account for the upward revision to the 2021 growth forecast (from 4.6% with a range between 2% and 6% in January, to 6.0% with a range between 3% and 7% in April). As a result, the output gap is expected to be smaller and to tighten more rapidly than projected in the previous report, though it is still expected to remain in negative territory on the forecast horizon. Wide forecast intervals reflect the fact that the future evolution of the COVID-19 pandemic remains a significant source of uncertainty on these projections. The delay in the recovery of economic activity as a result of the resurgence of COVID-19 in the first quarter appears to have been less significant than projected in the January report. The central forecast scenario expects this improved performance to continue in 2021 alongside increased consumer and business confidence. Low real interest rates and an active credit supply would also support this dynamic, and the overall conditions would be expected to spur a recovery in consumption and investment. Increased growth in public spending and public works based on the national government’s spending plan (Plan Financiero del Gobierno) are other factors to consider. Additionally, an expected recovery in global demand and higher projected prices for oil and coffee would further contribute to improved external revenues and would favor investment, in particular in the oil sector. Given the above, the technical staff’s 2021 growth forecast has been revised upward from 4.6% in January (range from 2% to 6%) to 6.0% in April (range from 3% to 7%). These projections account for the potential for the third wave of COVID-19 to have a larger and more persistent effect on the economy than the previous wave, while also supposing that there will not be any additional significant waves of the pandemic and that mobility restrictions will be relaxed as a result. Economic growth in 2022 is expected to be 3%, with a range between 1% and 5%. This figure would be lower than projected in the January report (3.6% with a range between 2% and 6%), due to a higher base of comparison given the upward revision to expected GDP in 2021. This forecast also takes into account the likely effects on private demand of a fiscal adjustment of the size currently being proposed by the national government, and which would come into effect in 2022. Excess in productive capacity is now expected to be lower than estimated in January but continues to be significant and affected by high levels of uncertainty, as reflected in the wide forecast intervals. The possibility of new waves of the virus (of uncertain intensity and duration) represents a significant downward risk to projected GDP growth, and is signaled by the lower limits of the ranges provided in this report. Inflation (1.51%) and inflation excluding food and regulated items (0.94%) declined in March compared to December, continuing below the 3% target. The decline in inflation in this period was below projections, explained in large part by unanticipated increases in the costs of certain foods (3.92%) and regulated items (1.52%). An increase in international food and shipping prices, increased foreign demand for beef, and specific upward pressures on perishable food supplies appear to explain a lower-than-expected deceleration in the consumer price index (CPI) for foods. An unexpected increase in regulated items prices came amid unanticipated increases in international fuel prices, on some utilities rates, and for regulated education prices. The decline in annual inflation excluding food and regulated items between December and March was in line with projections from January, though this included downward pressure from a significant reduction in telecommunications rates due to the imminent entry of a new operator. When controlling for the effects of this relative price change, inflation excluding food and regulated items exceeds levels forecast in the previous report. Within this indicator of core inflation, the CPI for goods (1.05%) accelerated due to a reversion of the effects of the VAT-free day in November, which was largely accounted for in February, and possibly by the transmission of a recent depreciation of the peso on domestic prices for certain items (electric and household appliances). For their part, services prices decelerated and showed the lowest rate of annual growth (0.89%) among the large consumer baskets in the CPI. Within the services basket, the annual change in rental prices continued to decline, while those services that continue to experience the most significant restrictions on returning to normal operations (tourism, cinemas, nightlife, etc.) continued to register significant price declines. As previously mentioned, telephone rates also fell significantly due to increased competition in the market. Total inflation is expected to continue to be affected by ample excesses in productive capacity for the remainder of 2021 and 2022, though less so than projected in January. As a result, convergence to the inflation target is now expected to be somewhat faster than estimated in the previous report, assuming the absence of significant additional outbreaks of COVID-19. The technical staff’s year-end inflation projections for 2021 and 2022 have increased, suggesting figures around 3% due largely to variation in food and regulated items prices. The projection for inflation excluding food and regulated items also increased, but remains below 3%. Price relief measures on indirect taxes implemented in 2020 are expected to lapse in the second quarter of 2021, generating a one-off effect on prices and temporarily affecting inflation excluding food and regulated items. However, indexation to low levels of past inflation, weak demand, and ample excess productive capacity are expected to keep core inflation below the target, near 2.3% at the end of 2021 (previously 2.1%). The reversion in 2021 of the effects of some price relief measures on utility rates from 2020 should lead to an increase in the CPI for regulated items in the second half of this year. Annual price changes are now expected to be higher than estimated in the January report due to an increased expected path for fuel prices and unanticipated increases in regulated education prices. The projection for the CPI for foods has increased compared to the previous report, taking into account certain factors that were not anticipated in January (a less favorable agricultural cycle, increased pressure from international prices, and transport costs). Given the above, year-end annual inflation for 2021 and 2022 is now expected to be 3% and 2.8%, respectively, which would be above projections from January (2.3% and 2,7%). For its part, expected inflation based on analyst surveys suggests year-end inflation in 2021 and 2022 of 2.8% and 3.1%, respectively. There remains significant uncertainty surrounding the inflation forecasts included in this report due to several factors: 1) the evolution of the pandemic; 2) the difficulty in evaluating the size and persistence of excess productive capacity; 3) the timing and manner in which price relief measures will lapse; and 4) the future behavior of food prices. Projected 2021 growth in foreign demand (4.4% to 5.2%) and the supposed average oil price (USD 53 to USD 61 per Brent benchmark barrel) were both revised upward. An increase in long-term international interest rates has been reflected in a depreciation of the peso and could result in relatively tighter external financial conditions for emerging market economies, including Colombia. Average growth among Colombia’s trade partners was greater than expected in the fourth quarter of 2020. This, together with a sizable fiscal stimulus approved in the United States and the onset of a massive global vaccination campaign, largely explains the projected increase in foreign demand growth in 2021. The resilience of the goods market in the face of global crisis and an expected normalization in international trade are additional factors. These considerations and the expected continuation of a gradual reduction of mobility restrictions abroad suggest that Colombia’s trade partners could grow on average by 5.2% in 2021 and around 3.4% in 2022. The improved prospects for global economic growth have led to an increase in current and expected oil prices. Production interruptions due to a heavy winter, reduced inventories, and increased supply restrictions instituted by producing countries have also contributed to the increase. Meanwhile, market forecasts and recent Federal Reserve pronouncements suggest that the benchmark interest rate in the U.S. will remain stable for the next two years. Nevertheless, a significant increase in public spending in the country has fostered expectations for greater growth and inflation, as well as increased uncertainty over the moment in which a normalization of monetary policy might begin. This has been reflected in an increase in long-term interest rates. In this context, emerging market economies in the region, including Colombia, have registered increases in sovereign risk premiums and long-term domestic interest rates, and a depreciation of local currencies against the dollar. Recent outbreaks of COVID-19 in several of these economies; limits on vaccine supply and the slow pace of immunization campaigns in some countries; a significant increase in public debt; and tensions between the United States and China, among other factors, all add to a high level of uncertainty surrounding interest rate spreads, external financing conditions, and the future performance of risk premiums. The impact that this environment could have on the exchange rate and on domestic financing conditions represent risks to the macroeconomic and monetary policy forecasts. Domestic financial conditions continue to favor recovery in economic activity. The transmission of reductions to the policy interest rate on credit rates has been significant. The banking portfolio continues to recover amid circumstances that have affected both the supply and demand for loans, and in which some credit risks have materialized. Preferential and ordinary commercial interest rates have fallen to a similar degree as the benchmark interest rate. As is generally the case, this transmission has come at a slower pace for consumer credit rates, and has been further delayed in the case of mortgage rates. Commercial credit levels stabilized above pre-pandemic levels in March, following an increase resulting from significant liquidity requirements for businesses in the second quarter of 2020. The consumer credit portfolio continued to recover and has now surpassed February 2020 levels, though overall growth in the portfolio remains low. At the same time, portfolio projections and default indicators have increased, and credit establishment earnings have come down. Despite this, credit disbursements continue to recover and solvency indicators remain well above regulatory minimums. 1.2 Monetary policy decision In its meetings in March and April the BDBR left the benchmark interest rate unchanged at 1.75%.

In 2024, the macroeconomic adjustment process continued, characterized by a sustained reduction in inflation that began in 2023 and a decline in the current account deficit of the balance of payments. This adjustment took place in the context of a contractionary monetary policy, with a gradual reduction in the monetary policy interest rate. GDP grew by 1.7%, driven by investment and consumption, while employment increased by 2.2%. Foreign reserves remained at adequate levels, and Banco de la República recorded a profit of COP 10,041 billion, benefiting from the returns on foreign reserves. Macroeconomic environment The International Monetary Fund (IMF) and the World Bank estimate that the global economy grew by 3.2% in 2024, a rate similar to that observed in 2023 (3.3%). This occurred in a context of moderating inflation and declining monetary policy interest rates in most countries. Global inflation moderated over the course of 2024. However, inflation rebounded toward the end of the year in some advanced economies, mainly due to rising energy costs. In Latin America, inflation trends were mixed. While some economies experienced sustained price stability, in most cases, inflation remained above the targets set by their respective central banks. Monetary policy interest rates in most Latin American economies continued to decline, reflecting a moderation in inflation and inflation expectations. However, some countries in the region recently raised interest rates in response to renewed inflationary pressures. Oil production increased in 2024, leading to a 3% decrease in oil prices, with Brent crude averaging around USD 80 per barrel. However, geopolitical tensions prevented a more pronounced decline. The U.S. dollar appreciated against most currencies, driven by expectations that the Federal Reserve (Fed) would implement more gradual policy rate cuts. In 2025, global economic growth is projected to be similar to that of 2024, supported by declining inflation, wage recovery, sustained employment growth, and a less restrictive monetary policy stance. However, geopolitical tensions and U.S. trade policies introduce uncertainty. More gradual reductions in the Fed’s interest rate are expected, with the possibility of pauses if inflationary pressures resurface. In Latin America, central banks are expected to continue cutting interest rates, although monetary policy may remain contractionary where inflation has not yet reached target levels. Domestic economic activity Colombia’s GDP grew by 1.7% in 2024, reflecting a moderate recovery compared to the previous year. This occurred in an environment of lower interest rates, improved domestic demand, and an increase in remittances and exports. Private consumption and fixed capital investment—particularly in infrastructure projects such as the Bogotá metro—contributed to economic growth. However, investment in housing declined. Agricultural and services sectors led economic growth, while mining and manufacturing contracted. The loan portfolio experienced low nominal growth, though some segments showed signs of recovery toward the end of the year. For 2025, economic activity is expected to continue recovering, approaching its productive capacity and aligning with the convergence of inflation toward its target. Employment Employment grew by 2.2% in 2024, resulting in the creation of 508,000 jobs. This expansion was driven by rural areas, where employment increased by 3.2%, surpassing the 1.4% growth in urban areas. The commerce, accommodation, manufacturing, public administration, health, and education sectors were the primary contributors to job creation. Wage employment grew by 2.7%, exceeding pre-pandemic levels, while non-wage employment increased by 1.8%, leading to a decline in informality to 55.6%. The national unemployment rate fell by 0.6 percentage points, reaching 9.7%, with a more pronounced reduction in rural areas. For 2025, the unemployment rate is expected to remain stable, supported by a positive economic outlook. Inflation and Monetary Policy Headline inflation in Colombia fell significantly from 9.3% in 2023 to 5.2% in 2024, primarily due to a restrictive monetary policy that moderated domestic demand and contributed to a reduction in the current account deficit. Core inflation (excluding food and regulated products) declined from 8.4% to 5.2%, reflecting the effectiveness of contractionary monetary policy. Inflation of goods dropped sharply, from 7.1% to 0.6%, due in part to the resolution of logistical disruptions and the appreciation of the peso. In contrast, services inflation declined more moderately, from 9% to 7%, influenced by indexation to past inflation and the increase in the minimum wage. Prices of food decreased from 5.0% to 3.3%, driven by lower pressures on processed food prices, benefiting from reduced costs of imported raw materials and a favorable exchange rate. Prices of regulated items dropped to 7.3%, following smaller adjustments in gasoline prices (after the required increases in 2023) and lower electricity and public service tariff increases, except for gas prices, which continued to rise. Inflation is expected to continue converging toward the 3% target in 2025, with headline inflation projected to close the year at around 4.1%, continuing its downward path into 2026. However, new risks have emerged, including a recent rise in producer costs, a significant increase in the minimum wage, and a rebound in inflation expectations. Balance of payments Colombia’s current account deficit narrowed to 1.7% of GDP between January and September 2024, down from 2.5% in the same period in 2023. This improvement was driven by higher remittance inflows, an improved services trade balance, and lower factor income outflows. Remittances reached a record USD 11,848 million, with the United States and Spain as the main sources of these inflows. A decline in the profits of foreign direct investment (FDI) companies, particularly in the oil and coal sectors, also contributed to reducing external imbalances. The trade deficit widened due to a greater imbalance in the trade of goods within a context of lower commodity prices. However, this was partially offset by strong agricultural and industrial exports. Additionally, the good performance of service exports, supported by higher international tourist arrivals, helped contain a larger trade imbalance. The financial account recorded net capital inflows equivalent to 1.1% of GDP, lower than the 2.5% recorded in 2023, primarily due to a decline in foreign direct investment in mining, transportation, and oil. This was partially offset by growth in financial and business services investment. The current account deficit is estimated to have closed 2024 at 1.8% of GDP, with a projected widening to 2.5% in 2025, in line with higher expected economic growth and stronger domestic demand. Public finances According to preliminary figures from the 2025 Financial Plan (PF-25) presented by the Ministry of Finance and Public Credit (MHCP), Colombia’s General Government deficit reached 4.8% of GDP in 2024, marking a 2.1 percentage-point increase compared to 2023. This deterioration was mainly driven by a worsening in the balances of the Central National Government (GNC) (2.6 pp) and the Social Security subsector (0.4 pp), partially offset by a 0.8 pp improvement in Regional and Local Government balances. The reduction in the deficit position of the Fuel Price Stabilization Fund (FEPC for its acronym in Spanish) was notable, following gasoline price adjustments, which closed the gap between the reference price and local market prices. However, fiscal pressures persist due to ongoing subsidies for ACPM (diesel fuel). The total and primary deficits of the Central Government stood at 6.8% and 2.4% of GDP, respectively, driven by a decline in tax revenue—particularly from income and external taxes—alongside increased government spending. The net debt of the Central Government increased to 60% of GDP, exceeding previous forecasts. For 2025, a total and primary deficit of 5.1% and 0.2% of GDP is projected, with tax revenue expected to grow by 22.6%. Compliance with the fiscal rule and the stabilization of public finances will be critical in 2025, given the potential impact of fiscal slippage on the country’s risk premiums. Failure to meet fiscal targets could raise interest rates for both the Government and the broader economy. Maintaining credibility in fiscal policy will be key to preventing macroeconomic adjustments from exerting additional pressure on interest rates. International Reserves As of December 31, 2024, Colombia’s net international reserves stood at USD 62,481 million, reflecting an increase of USD 2,873 million during the year. This growth was primarily driven by returns on reserves, which reached 3.65%, benefiting from higher global interest rates, and Banco de la República's reserve accumulation program, which added USD 1,479.4 million to reserves. According to the IMF’s reserve adequacy methodology, Colombia maintains a reserve ratio of 1.29. This falls within the adequate range (1.0 – 1.5), indicating that Colombia’s reserves are sufficient to withstand extreme external shocks and balance of payments risks. Profits obtained by Banco de la República The Bank's profits reached a record COP 10,041 billion in 2024, resulting from revenues of COP 13,948 billion and expenses of COP 3,907 billion. Profits increased by COP 815 billion compared to 2023, primarily due to lower expenses, although partially offset by a decline in revenues. For 2025, profits are projected at COP 10,512 billion, supported by the high expected profitability of foreign reserves. However, this projection is subject to uncertainty related to reserve performance and monetary base growth.

In the IDB Group, diversity is in the cornerstone of everything we do in Latin America and the Caribbean. We strongly believe that an active investment in Diversity, Equity, and Inclusion (DEI) entails many institutional benefits including more innovative solutions for our clients, and a stronger position in capital markets, and an overall perception as a preferred place to work. Recognizing our diversity and our commitment to making our organization more inclusive and equitable is what makes our institution the premier development finance institution for Latin America and the Caribbean, and the reason why we have included DEI in our Institutional Strategy and the Vision 2025. In 2021, we achieved significant milestones including becoming the first multilateral development bank in the Americas, and the second worldwide, to achieve the EDGE Move certification, the second level in a three level globally recognized gender certification, and the integration of equity as a core principle of our strategy thus ensuring a focus on the individual needs of our employees and provide fair opportunities and an equal outcome for all. Our institution still has much work to do in DEI, and we intend to be the standard-bearer in the Region and a source of inspiration and guidance for our clients. What is being highlighted in this DEI 2021 Report are the crucial steps taken to lay a path to better results within the IDB Group. For example, we continue to complete a gender pay gap analysis annually. In 2021, the analysis results for the IDB estimated an unexplained wage differential for base salaries of 0.8% in favor of men. While for IDB Invest, the analysis results estimated the unexplained wage differential for base salaries of 2.8% in favor of men. Putting this into context, our differential is less than /- 5% which is considered statistically insignificant by the Economic Dividends for Gender Equality (EDGE) standards. This report describes our efforts to advance this DEI agenda during 2021. We highlight our best practices to develop an organizational culture that encourages diverse experiences, measure our progress in numbers, and share the initiatives, actions, and targets we have set up for the upcoming years.

Macroeconomic summary The Colombian economy sustained numerous shocks in the second quarter, pri¬marily related to costs and supply. The majority of these shocks were unantic¬ipated or proved more persistent than expected, interrupting the recovery in economic activity observed at the beginning of the year and pushing overall inflation above the target. Core inflation (excluding food and regulated items) increased but remained low, in line with the technical staff’s expectations. A third wave of the pandemic, which became more severe and prolonged than the previous outbreak, began in early April. This had both a high cost in terms of human life and a negative impact on Colombia's economic recovery. Between May and mid-June roadblocks and other disruptions to public order had a sig¬nificant negative effect on economic activity and inflation. The combination and magnitude of these two shocks likely led to a decline in gross domestic product (GDP) compared to the first quarter. Roadblocks also led to a significant in¬crease in food prices. The accumulated effects of global disruptions to certain value chains and increased international freight transportation prices, which since the end of 2020 have restricted supply and increased costs, also affected Colombia’s economy. The factors described above, which primarily affected the consumer price index (CPI) for goods and foods, explain to a significant degree the technical staff’s forecast errors and the increase in overall inflation above the 3% target. By contrast, increases in core inflation and in prices for regulated items were in line with the technical staff’s expectations, and can be explained largely by the elimination of various price relief measures put in place last year. An increase in perceived sovereign risk and the upward pressures that this im¬plies on international financing costs and the exchange rate were further con¬siderations. Despite significant negative shocks, economic growth in the first half of the year (9.1%) is now expected to be significantly higher than projected in the April re¬port (7.1%), a sign of a more dynamic economy that could recover more quickly than previously forecast. Diverse economic activity figures have indicated high¬er-than-expected growth since the end of 2020. This suggests that the negative effects on output from recurring waves of COVID-19 have grown weaker and less long-lasting with subsequent outbreaks. Nevertheless, the third wave of the coro¬navirus, and to an even greater degree the previously mentioned roadblocks and disruptions to public order, likely led to a decline in GDP in the second quar¬ter compared to the first. Despite this, data from the monthly economic tracking indicator (ISE) for April and May surpassed expectations, and new sector-level measures of economic activity suggest that the negative impact of the pandemic on output continues to moderate, amid reduced restrictions on mobility and im¬provements in the pace of vaccination programs. Freight transportation registers (June) and unregulated energy demand (July), among other indicators, suggest a significant recovery following the roadblocks in May. Given the above, annual GDP growth in the second quarter is expected to have been around 17.3% (previously 15.8%), explained in large part by a low basis of comparison. The technical staff revised its growth projection for 2021 upward from 6% to 7.5%. This forecast, which comes with an unusually high degree of uncertain¬ty, assumes no additional disruptions to public order and that any new waves of COVID-19 will not have significant additional negative effects on economic activity. Recovery in international demand, price levels for some of Colombia’s export com¬modities, and remittances from workers abroad have all performed better than projected in the previous report. This dynamic is expected to continue to drive recovery in the national income over the rest of the year. Continued ample international liquidity, an acceleration in vacci¬nation programs, and low interest rates can also be ex¬pected to favor economic activity. Improved performance in the second quarter, which led to an upward growth revision for all components of spending, is expected to continue, with the economy returning to 2019 production levels at the end of 2021, earlier than estimated in the April report. This forecast continues to account for the short-term effects on aggregate demand of a tax reform package along the lines of what is currently being pro-posed by the national government. Given the above, the central forecast scenario in this report projects growth in 2021 of 7.5% and in 2022 of 3.1% (Graph 1.1). In this scenar¬io, economic activity would nonetheless remain below potential. The noted improvement in these projections comes with a high degree of uncertainty. Annual inflation increased more than expected in June (3.63%) as a result of changes in food prices, while growth in core inflation (1.87%) was similar to projections.