An investigation into moving electromagnetic near-field hotspots inside a resonant cavity is presented. The investigation focused on simulating an alternative approach to microwave thermal ablation of tumours by manipulating the interaction between electromagnetic near fields instead of utilising an interstitial antenna. The methodology comprised comparing various electromagnetic field solvers, verifying the simulation techniques, characterising a rectangular resonant cavity, and attempting to manipulate the position of its hotspots by introducing a feed phase shift. The effects of dielectric media were also investigated. Progressive hotspot movement was achieved using input phase manipulation between 2.55 and 2.7 GHz with the feeds on opposite walls. No pattern change was evident at the system's eigenfrequencies, indicating a constant field pattern at its resonant peaks. Furthermore, it was determined that the characteristic modes of the system were narrowband, such that the addition of dielectric material altered the system's resonance. Therefore, the application of this method to thermal ablation, which requires high precision, accuracy and control, was deemed impractical. Future recommendations include using adjustable geometry to design field patterns, comparing dielectric media with significant thermal mass, and investigating the 'inverse problem' to create a specific current distribution around the resonant cavity and induce the desired hotspot patterns.

As ondas eletromagnéticas estão presentes em diversas aplicações tecnológicas do cotidiano, desde telecomunicações até questões relacionadas ao aquecimento global e cuidados com a saúde. Assim, a inclusão de produtos educacionais experimentais, expositivos e lúdicos sobre este assunto não pode ser negligenciada no ensino formal. O presente trabalho apresenta a construção de um produto educacional (PE) experimental e interativo que apresenta a dependência da cor em relação à luz visível, assim como o fenômeno da luminescência em alguns materiais quando expostos à radiação ultravioleta. Trata-se de uma câmara escura equipada com lâmpadas nas cores, vermelha, verde e azul, além de uma fonte ultravioleta (UV). O dispositivo foi construído utilizando materiais acessíveis e de baixo custo. As lâmpadas podem ser ligadas independentemente ou em conjunto, e a percepção da cor do objeto dependerá das cores da luz que o ilumina. Portanto, o PE pode ser empregado no estudo da teoria das cores. A inclusão da fonte UV permite a observação da luminescência de objetos quando expostos a ela, fenômeno frequentemente retrato em filmes e séries policiais. Essas substâncias fotoluminescentes estão presentes em diversos materiais, como papel sulfite e sabão em pó. cotidiano saúde Assim experimentais formal (PE visível Tratase Trata se vermelha azul UV. . (UV) custo conjunto ilumina Portanto ela policiais pó (UV

Electromagnetic waves play a crucial role in various technological applications in our daily lives, ranging from telecommunications to issues related to global warming and healthcare. Therefore, the inclusion of experimental, expository, and playful educational products on this subject cannot be neglected in formal education. This study introduces the development of an experimental and interactive educational product (EP) designed to elucidate the relationship between color and visible light, as well as the luminescent phenomenon exhibited by certain materials when exposed to ultraviolet radiation (UV). The EP is cost-effective and accessible, comprising a dark box equipped with red, green, blue, and UV lamps. These lamps can be turned on individually or collectively, influencing the perceived color of an object based on the illuminating light’s color. Thus, the EP serves as a valuable resource for studying the theory of colors. The inclusion of a UV light source allows for the observation of luminescent properties in objects exposed to it, a feature commonly portrayed in crime movies and TV series. Photoluminescent substances are present in various materials, including sulfite paper and laundry detergent. Consequently, this EP emerges as an effective tool for introducing quantum mechanics concepts in the classroom. lives healthcare Therefore expository education (EP UV. . (UV) costeffective cost accessible red green blue collectively lights s Thus colors it series detergent Consequently classroom (UV

Estudos recentes têm renovado o esforço de chamar a atenção para a narrativa pseudo-histórica que descreve os resultados experimentais de Philipp Lenard sobre o efeito fotoelétrico como inexplicáveis e inconsistentes diante das predições da teoria ondulatória-eletromagnética clássica. No entanto, ao analisar o período de transição entre a rejeição e a aceitação da “hipótese de quantum de luz” de Albert Einstein, identificam-se pelo menos seis tentativas clássicas de interpretação do efeito fotoelétrico, as quais raramente são discutidas em livros didáticos ou textos acadêmicos. Neste primeiro artigo de uma série de três, são apresentadas quatro hipóteses clássicas de como o efeito fotoelétrico é produzido, formuladas, respectivamente, por Philipp Lenard (uma), Arthur E. Haas (uma) e por Joseph J. Thomson (duas). Os resultados fornecem subsídios para que professores e estudantes possam explorar aspectos conceituais, procedimentais e epistemológicos no contexto do desenvolvimento inicial da teoria quântica, a partir de uma visão problematizadora e histórica da atividade científica. pseudohistórica pseudo ondulatóriaeletromagnética ondulatória eletromagnética clássica entanto hipótese luz Einstein identificamse identificam se acadêmicos três produzido formuladas respectivamente uma, , E (uma J duas. duas . (duas) conceituais quântica científica (duas

Recent studies have renewed efforts to draw attention to the pseudo-historical narrative describing Philipp Lenard’s experimental results on the photoelectric effect as inexplicable and inconsistent with predictions of classical wave-electromagnetic theory. However, in examining the transition period between the rejection and acceptance of Albert Einstein’s “quantum of light hypothesis”, at least six classical attempts to interpret the photoelectric effect can be identified, rarely discussed in textbooks or academic texts. In this first article of a three-part series, four classical hypotheses on how the photoelectric effect is produced are presented, formulated respectively by Philipp Lenard (one), Arthur E. Haas (one), and by Joseph J. Thomson (two). The findings provide insights for teachers and students to explore conceptual, procedural, and epistemological aspects in the context of the early development of quantum theory, from a problematizing and historical perspective on scientific activity. pseudohistorical pseudo Lenards s waveelectromagnetic wave electromagnetic theory However Einsteins Einstein hypothesis, hypothesis , hypothesis” identified texts threepart three part series presented one, one (one) E J two. two . (two) conceptual procedural activity (one (two

A simetria de “gauge” e, em consequência, as teorias de calibre, que de forma natural se estabeleceram no contexto da teoria eletromagnética, constituem uma abordagem muito apropriada e bem-sucedida para descrever as interações eletrofracas e fortes, e consolidaram as teorias quânticas de campo como uma formulação universal para tratar as diferentes interações fundamentais. O sucesso desta proposta é devido ao fato de que, incluindo um campo de calibre como mediador de uma dada interação, emerge um formalismo padrão para descrever os campos de força conhecidos. Nesta contribuição, adotamos o exemplo dos osciladores bidimensionais harmônicos/anarmônicos clássicos para apresentar, de forma introdutória, o procedimento geral de construção de uma teoria de calibre. Para relacionar esta discussão com um cenário de uma teoria de campos, partimos da eletrodinâmica escalar e utilizamos a técnica de redução dimensional para se chegar à lagrangiana de um sistema mecânico. E, com este exemplo, tentamos motivar e mostrar por que é necessário que os campos de calibre devem corresponder a graus de liberdade dinâmicos. gauge “gauge consequência eletromagnética bemsucedida bem sucedida fortes fundamentais interação conhecidos contribuição harmônicosanarmônicos harmônicos anarmônicos apresentar introdutória mecânico E dinâmicos

Gauge symmetry and, consequently, gauge theories, which emerge naturally in the context of the electromagnetic theory, in their non-Abelian version encompass electroweak and strong interactions; this has consolidated quantum field theories as a way of systematically describing the processes of fundamental particles. The success of this proposal is due to the fact that, by including a gauge field as the mediator of an interaction, a universal formulation may be adopted to describe the diverse fundamental interactions. In this contribution, we pick out the example of classical harmonic/anharmonic two-dimensional oscillators to endeavour a presentation of gauge theories in an introductory way, compatible with the level of knowledge of an undergraduate course. To relate this discussion to a field-theory scenario, we start off from the scalar electrodynamics and make use of a dimensional reduction technique to get a Lagrangian of a classical mechanical system. In this scenario, we motivate and justify why, besides ensuring local invariance, gauge fields must correspond to propagating degrees of freedom. consequently theory nonAbelian non Abelian interactions particles that interaction contribution harmonicanharmonic harmonic anharmonic twodimensional two course fieldtheory scenario system why invariance freedom

Article This paper develops an easy design analysis for a simple high selective T-shaped band-stop filter (BSF) loaded with a capacitance. It applies the developed design theory to obtain an appropriate capacitance value for tuning the cut-off frequency. This paper clearly explains the design mechanism for such a simple tunable BSF using ABCD matrices. Simulated filters loaded with capacitances (up to 1.1 pF) show a change in rejection frequencies from 2 GHz (un-tuned) down to 1.047 GHz with 50dB rejection and around 36% -3dB fractional bandwidth. It also shows the effect on pass frequencies which change from 1 GHz down to 111 MHz, while the separation between pass and stop frequency remains around 1 GHz. Measurements on fabricated prototypes match the simulation and theory for tunable frequencies closely. It also compares the performance of the filter with previously reported similar structures. Tshaped T shaped bandstop band (BSF cutoff cut off matrices up 11 1. pF untuned un tuned (un-tuned 1047 047 1.04 dB 36 3dB bandwidth MHz closely structures 104 04 1.0 3 10 0

Abstract This paper presents outcomes of a comprehensive investigation of the performance features of the compressed-vdipole antenna, recently introduced in the literature as being particularly suitable for unmanned surface boat applications. The moment-method solution to the rigorously formulated electric field integral equations for the problem, provided an approximation to the distribution of current on the antenna. A comparison of computational results due to this formulation with available measurement data demonstrated very good agreement between the two; to lend credence to the validity of the formulation. Profiles of the antenna’s input and radiation-zone characteristics (including input impedance, return loss, E-field patterns, and maximum directivity) presented in the paper describe how choice of apex angle, antenna electrical length, and degree of compression, influence the performance of the antenna. compressedvdipole compressed vdipole applications momentmethod moment method problem two antennas s radiationzone radiation zone including impedance loss Efield E patterns directivity angle length compression

Abstract The equivalent wave impedance circuit model (ECM-WI) is presented for the analysis of frequency selective surfaces (FSS). The development of the analytical model is based on homogenization theory, as well as analogies between wave theory and transmission line theory. The coplanar strip model and the concept of wave impedance are used to scale the Marcuvitz model for periodic strip gratings of conductive strips, as well as to consider the influence of the presence of a lossy dielectric substrate on the frequency response of the FSS. In particular, the model is applied to the analysis of square loop FSSs and considering the normal incidence. The results obtained are presented by comparing full-wave simulations for the two proposed models, obtaining average deviations in absolute values (%) of 2.11 and 0.38 for resonance frequency and 3.45 and 5.49 for bandwidth. The prototype manufactured in FR-4 obtained a deviation of 2.56% for resonance frequency and 2.79% for bandwidth. ECMWI ECM WI (ECM-WI FSS . (FSS) strips particular incidence fullwave full models % (% 211 2 11 2.1 038 0 38 0.3 345 3 45 3.4 549 5 49 5.4 bandwidth FR4 FR 4 FR- 256 56 2.56 279 79 2.79 (FSS ( 21 1 2. 03 0. 34 3. 54 5. 25 2.5 27 7 2.7

Apresentamos neste trabalho uma abordagem pedagógica da descrição do núcleo atômico a partir do modelo de camadas. A análise proposta está alicerçada na equação de Schrödinger. Neste sentido, analisamos dois sistemas, ambos baseadas na teoria de campo médio, em que as interações nucleares e eletromagnéticas são modeladas por osciladores harmônicos, mas que em um deles a interação entre os spins dos núcleons é considerada. Como resultado, alguns aspectos do núcleo foram explicados, onde merece destaque a obtenção dos números mágicos nucleares. Assim, a abordagem proposta pode ser utilizada em cursos de mecânica quântica, como aplicação da equação de Schrödinger, bem como em disciplinas de física e engenharia nuclear. camadas Schrödinger sentido sistemas médio harmônicos considerada resultado explicados Assim quântica nuclear

In this work, we present a pedagogical approach to describing the atomic nucleus based on the shell model. The proposed analysis is based on the Schrödinger equation. In this sense, we analyze two systems, both based on mean field theory, in which nuclear and electromagnetic interactions are modeled by harmonic oscillators, but in one of them the interaction between the nucleon spins is considered. As a result, some aspects of the nucleus were explained, where the obtaining of nuclear magic numbers deserves emphasis. Thus, the proposed approach can be used in quantum mechanics courses, such as the application of the Schrödinger equation, as well as in physics and nuclear engineering subjects. work model equation sense systems theory oscillators considered result explained emphasis Thus courses subjects

Abstract A novel planar balanced-to-balanced (BTB) microstrip filtering crossover with high isolation and common-mode (CM) suppression is proposed in this paper. The circuit structure is based on microstrip transmission lines without coupling sections, which can reduce insertion loss and enhance isolation. Specific theoretical analysis of the BTB filtering crossover configuration using transfer matrix and mixed-mode scattering parameters is performed. In order to verify the validity of the theory analysis and design, a microstrip BTB filtering crossover prototype at the center frequency of 2.45 GHz is fabricated and measured with high isolation and excellent CM suppression. balancedtobalanced balanced (BTB commonmode common mode (CM paper sections mixedmode mixed performed design 245 2 45 2.4 24 4 2.

We present an engaging educational demonstration designed to captivate students’ attention. The experiment reveals an intriguing phenomenon – a surprising attraction between two magnets with identical poles facing each other when a steel metal sphere is inserted between them. Our exploration focuses on both qualitative and quantitative aspects of this magnetic interaction. Specifically, we examine the interaction between two neodymium cylindrical magnets with the like poles facing each other. The experimental setup we introduce allows for the precise measurements of the magnetic force between the magnets. To gain a quantitative understanding of our measurements, we employ electromagnetic theory. This theoretical framework allows us to determine the magnetic energy within the system and to easily calculate the force between the magnets. students attention them Specifically theory

Abstract This paper presents a radiopropagation algorithm based on a Ray Tracing (RT) technique that combines a modified multipath model for constant refractivity gradient profiles and the Uniform Theory of Diffraction (UTD). A novel formulation is proposed by the authors for calculation and ground-reflection analysis of ray paths depending on atmospheric refractivity. The algorithm introduced herein was evaluated in a mixed scenario and in two more realistic case studies, under conditions of constant refractivity gradient and lossy terrain profiles. Pathloss results are obtained and compared with Parabolic Equation (PE) numerical solution results at 2.0 GHz, 3.5 GHz and 5.4 GHz. In such conditions, the modified radiopropagation multipath algorithm with atmospheric refractivity introduced herein showed satisfactory results. RT (RT UTD. UTD . (UTD) groundreflection ground reflection studies PE (PE 20 2 0 2. 35 3 5 3. 54 4 5. (UTD

Resumen: En este estudio se evalúan las propiedades ópticas y electroconductoras de los oligómeros derivados del compuesto tiazolo[5,4-d]tiazol constituidos por 4, 6, 8, 10 y 20 unidades, respectivamente, mediante la teoría de los funcionales de la densidad (DFT) y funcionales de la densidad dependiente del tiempo (TD-DFT). Se calculan la brecha de energía prohibida (Eg), la afinidad electrónica (VAE), la energía de ionización (VIP), la dureza química y las propiedades ópticas como el espectro de emisión y osciladores de fuerza. Los espectros de emisión predichos muestran que la emisión del oligómero se registra con una intensidad alta dentro de la región visible correspondiente al verde en el espectro electromagnético. Se concluye que los oligómeros de tiazolo[5,4-d]tiazol son buenos candidatos para ser usados como material de transporte de carga o material emisor en el diseño de diodos orgánicos emisores de luz (OLED), debido a que muestran buenas propiedades de conducción eléctrica y de transporte de carga.

Abstract: This study assesses the optical and electroconductive properties of oligomers derived from the thiazolo[5,4-d]thiazole compound consisting of 4, 6, 8, 10, and 20 units, respectively, by applying the density functional theory (DFT) and the time-dependent density functional theory (TD-DFT). Band gap (Eg), electron affinity (VAE), ionization energy (VIP), chemical hardness, and optical properties such as emission spectrum and force oscillators are calculated. The predicted emission spectra show that the oligomer’s emission is recorded with high intensity within the green visible light region of the electromagnetic spectrum. It is concluded that thiazolo[5,4-d]thiazole oligomers are good candidates as charge transport material and as emitting material when designing organic light-emitting diodes (OLED) since they show appropriate emission properties, electrical conduction, and freight transport.

Abstract This paper presents an effective and novel design procedure employing a novelty named as Perturbation Factor to predict the resonance frequency of resonant cavities in SIW technology perturbed by a shape perturbation. The design procedure can be applied in tunable cavities and bandpass filters with shunt reactance of symmetrical inductive window, and regarding the application technologies, rectangular waveguide resonators and resonant cavities in SIW can be employed due to the equivalence of operation between both technologies. Its straightforward application allows a frequency variation of up to 20% using only one metal post which allows the reduction of the fabrication cost and the preservation of the frequency response across the considered bandwidth. To validate the design procedure, two resonant cavities were fabricated, a rectangular resonant cavity designed to operate at 5.0 GHz and 6.0 GHz and a square resonant cavity designed to operate at 6.0 GHz and 7.2 GHz, and frequency variations of 17.74% and 21.81% were obtained for the rectangular and square cavities, respectively. Still regarding the reached results, was verified a mean error of 1.75% for the predicted resonance frequency, which validates the design procedure. The experimental results are in good agreement with the full-wave computational results and electromagnetic theory. perturbation window technologies 20 bandwidth fabricated 50 5 0 5. 60 6 6. 72 7 2 7. 1774 17 74 17.74 2181 21 81 21.81 respectively 175 1 75 1.75 fullwave full wave theory 177 17.7 218 8 21.8 1.7 17. 21. 1.

Abstract The theory of multiconductor transmission lines is based on the principle of superposition. According to this principle, any electric or magnetic field can be represented as the sum of individual electric or magnetic fields. This theory is used to analyze and design electrical systems involving multiple conductors. In this work, the procedures for analyzing electromagnetic transients in 3-conductor transmission lines are presented, which is the last step for generalization in the case of lines to “n” conductors. The paper presents elementary cases and a more general one to illustrate such an approach.

Abstract In this article, we review the dynamics of charge carriers in graphene and related 2D systems from a quantum field theoretical point of view. By allowing the electromagnetic fields to propagate throughout space and constraining fermions to move on a 2D manifold, the effective theory of such systems becomes a non-local version of quantum electrodynamics (QED) dubbed in literature pseudo or reduced QED. We review some aspects of the theory assuming the coupling arbitrary in strength. In particular, we focus on the chiral symmetry breaking scenarios and the analytical structure of the fermion propagator in vacuum and under the influence of external agents like a heat bath, in the presence of a Chern-Simons term, anisotropy and in curved space. We briefly discuss the major advances and some new results on this field.