Materials with properties that can be described by a near-zero index of refraction have received significant attention in the fields of electromagnetics, optics, and acoustics, due to their extraordinary capabilities ...
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Materials with properties that can be described by a near-zero index of refraction have received significant attention in the fields of electromagnetics, optics, and acoustics, due to their extraordinary capabilities in wave manipulation. It was recently demonstrated theoretically and experimentally that acoustic waves could manifest near-zero-index propagation based on the effective compressibility of a waveguide channel approaching zero. In turn, this allows tunneling of acoustic waves with nearly infinite wavelength (or equivalently, uniform phase) when the channel cross section is much larger than the feeding lines. Here, we show that these concepts can be leveraged to realize an acoustic power divider and multiplexer offering tunneling of sound to an arbitrary number of output ports, with phase shifts equal to 0° or 180° and robust response to variations in the port position. We present analytical and numerical models describing the properties of this device and study limitations and trade-offs that occur in the presence of losses as the device size is scaled.
This paper proposes to complement the current regulatory agencies’ methodology for evaluating exposure to Radiofrequency Electromagnetic Fields (RF-EMF) in buildings under the direct incidence of emissions from Base ...
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This paper proposes to complement the current regulatory agencies’ methodology for evaluating exposure to Radiofrequency Electromagnetic Fields (RF-EMF) in buildings under the direct incidence of emissions from Base Station (BS) antennas. The key contribution is the refinement of measurement point selection within buildings, ensuring that assessments more accurately capture exposure levels. The approach employs technical criteria for selecting target buildings, considering the location of the BSs and the configuration of the surrounding antenna structures. The proposed approach was applied to measurements in four buildings in the city of Natal, the capital of Rio Grande do Norte, located in the Northeast region of Brazil. The results show electric field intensity peaks up to 17.40 times higher and averages up to 14.13 times higher than values obtained from measurements conducted at ground level, such as those carried out by the National Telecommunications Agency (ANATEL). The highest exposure rates reached 82.27% and 59.43% of the limits established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for the frequency bands of FM radio and mobile telephony, respectively. Our proposal can improve and complement the normative guidelines for RF-EMF exposure assessment, providing more representative evaluations of exposure in indoor building environments near modern telecommunication infrastructure.
Schistosomiasis is an infectious disease caused by the parasite Schistosoma mansoni , and it is a significant health concern in many underdeveloped tropical regions. The traditional method of diagnosing schistosomiasi...
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Schistosomiasis is an infectious disease caused by the parasite Schistosoma mansoni , and it is a significant health concern in many underdeveloped tropical regions. The traditional method of diagnosing schistosomiasis involves fecal examinations under a microscope for parasite eggs, a process that is time consuming, error-prone, and requires specialized training. Artificial intelligence encompasses a broad range of techniques, including both machine learning and its subset, deep learning, which have been successful in solving such problems. Therefore, this study aimed to propose an automated solution that combines DL-based object detection methods with classical ML techniques and HOG feature extraction to identify S. mansoni eggs in images obtained using the Kato-Katz parasitological technique. A real database of 1100 images was created, processed, and annotated by three parasitologists. The proposed system achieved an Average Precision of 0.884 for an @[IoU = 0.50] using a Faster R-CNN method with ResNet-50 architecture over the best-annotated data, outperforming other detection models. Based on a threshold analysis, we suggest an integrated approach with a voting scheme of machine learning models to improve results in terms of false positives and false negatives. Comparative analysis with external data and a commercial tool confirmed that our approach offers promising results and applicability to assist health professionals in diagnosing schistosomiasis in public health systems, such as the Brazilian Unified Health System (SUS), potentially improving diagnosis speed and accuracy in endemic regions.
This paper describes our effort to build a set of models for nano-oscillator systems that is compatible with modern EDA design tools. We have implemented a set of hierarchical models that spans an abstraction hierarch...
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We have been studying on estimating distribution of permittivity between measurement electrodes using capacitance and electric potential. Two arc electrodes were separated by long distance and there electrodes were su...
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We have been studying on measuring capacitance and potential using long distance electrode for estimating a permittivity distribution. The estimating method of permittivity distribution was proposed using Finite Eleme...
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This paper presents an evaluation of requirements specification for two critical real-time control systems, which depends of industrial communications protocols. It is proposed the use of aspect-oriented modeling (AOM...
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We have studied the resonant and nonperturbative coupling of transverse optical phonons in lead telluride with photons in small-mode-volume terahertz cavities, observing a giant vacuum Rabi splitting on the order of t...
We have studied the resonant and nonperturbative coupling of transverse optical phonons in lead telluride with photons in small-mode-volume terahertz cavities, observing a giant vacuum Rabi splitting on the order of the uncoupled phonon and cavity frequencies. Our terahertz time-domain spectroscopy experimental data, systematically collected as a function of sample thickness, temperature, and cavity length, can be well reproduced by our electromagnetic simulations. These results demonstrate that this uniquely tunable platform is promising for realizing and understanding predicted cavity-vacuum-induced ferroelectric instabilities, as well as for exploring applications of light-matter coupling in the ultra-and deep-strong coupling regimes in quantum technology.
We have investigated the resonant coupling of photons with TO phonons in lead telluride in small-mode-volume terahertz cavities, observing a giant vacuum Rabi splitting on the order of the bare cavity–phonon frequency.
ISBN:
(纸本)9781957171258
We have investigated the resonant coupling of photons with TO phonons in lead telluride in small-mode-volume terahertz cavities, observing a giant vacuum Rabi splitting on the order of the bare cavity–phonon frequency.
In this current digital era, the video game is favorite especially among young people. Besides widely known as a form of entertainment, some messages or lessons can be learned from a video game that may affect the pla...
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