Features such as photon rings, jets, or hot spots can leave particular topological signatures in a black hole image. As such, topological data analysis can be used to characterize images resulting from high resolution...
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Twisted 2D materials form complex moiré structures that spontaneously reduce symmetry through picoscale deformation within a mesoscale lattice. We show twisted 2D materials contain a torsional displacement field ...
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We developed new nanocrystalline Fe-Co-B-P-Cu soft magnetic alloys and studied their magnetic properties by calculating electronic structures using first-principles calculations based on density functional theory with...
We developed new nanocrystalline Fe-Co-B-P-Cu soft magnetic alloys and studied their magnetic properties by calculating electronic structures using first-principles calculations based on density functional theory within the local spin density approximation and the Brillouin function. The supercell Fe-B-P-Cu was equilibrated at 3000 K for 12 ps using ab initio molecular dynamics (AIMD). Consequently, Fe, B, P, and Cu atoms are distributed randomly in an amorphous matrix formed by cooling it to 0 K. The ferromagnetic bcc α -(Fe 50 Co 50 ) crystallites were formed in the amorphous matrix by annealing the mixture at 300 K and cooling to 0 K. This resulted in the formation of nanocrystalline (Fe, Co)-B-P-Cu soft magnetic alloys. The ferromagnetic bcc α -Fe(Co) crystallites, embedded in an amorphous matrix, were confirmed experimentally for the first time. The experiment involved quickly cooling and heating a melted mixture of Fe, Co, B, Fe 3 P, and Cu to create both amorphous ribbons and crystallites. The Fe-Co-B-P-Cu alloy designed for the experiment has a saturation magnetization ( μ 0 M S ) of over 1.9 T (T) at 0 K and ranging from 1.87 to 1.92 T at 300 K. The magnetocrystalline anisotropy constant (K) decreased significantly to 142 J/m 3 from 5.2 × 104 J/m 3 with an increase in the number of embedded crystallites from one to five, indicating that the alloy became magnetically soft. At 300 K, the experimental μ 0 M S ranged from 1.79 to 1.89 T. Additionally, as the concentration of Co increased, the Curie temperature (T C ) also increased and reached about 800 °C at 3.5 at.%. The study revealed that the average grain size of the synthesized Fe-Co-B-P-Cu alloys was 29 nm. The experimental μ 0 M S was slightly lower than the calculated value for all designed Fe-Co-B-P-Cu alloys, indicating that the recrystallization process was not entirely controlled. The experimental results confirmed that the designed alloy system has achieved the target saturation magnetization of o
The Internet of Things (IoT) paradigm aims to bring continuous interaction between small embedded devices and humans. The IoT has the potential to affect our daily lives and bring many benefits to society. Low-Power W...
ISBN:
(数字)9781728139494
ISBN:
(纸本)9781728139500
The Internet of Things (IoT) paradigm aims to bring continuous interaction between small embedded devices and humans. The IoT has the potential to affect our daily lives and bring many benefits to society. Low-Power Wide-Area Networks (LPWAN) is a new IoT technology that offers long distance connectivity for a massive number of devices. LPWAN is a promising solution to enable complex IoT scenarios, such as smart cities and smart healthcare. LoRa is currently one of the leading LPWAN solutions available for public use. Due to the great number of connected devices and, in some cases, sensitive data transmitted in IoT networks, security is one of the main concerns in LPWAN. In this paper, we focus on the issues of key management in LoRaWAN. We propose a secure architecture for key management based on private blockchain and smart contracts in order to increase the levels of security and availability in LoRaWAN environments. In order to show the feasibility of the proposed architecture, a working prototype was implemented using open-source tools and commodity hardware.
Recently, Vehicular Cloud Communication (VCC) has been gaining momentum targeting intelligent and efficient data transmission. VCC is a type of mobile ad-hoc network comprising heterogeneous vehicles sharing their res...
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The brain modifies its synaptic strengths during learning in order to better adapt to its environment. However, the underlying plasticity rules that govern learning are unknown. Many proposals have been suggested, inc...
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KAGRA, the underground and cryogenic gravitational-wave detector, was operated for its solo observation from February 25 to March 10, 2020, and its first joint observation with the GEO 600 detector from April 7 to Apr...
KAGRA, the underground and cryogenic gravitational-wave detector, was operated for its solo observation from February 25 to March 10, 2020, and its first joint observation with the GEO 600 detector from April 7 to April 21, 2020 (O3GK). This study presents an overview of the input optics systems of the KAGRA detector, which consist of various optical systems, such as a laser source, its intensity and frequency stabilization systems, modulators, a Faraday isolator, mode-matching telescopes, and a high-power beam dump. These optics were successfully delivered to the KAGRA interferometer and operated stably during the observations. The laser frequency noise was observed to limit the detector sensitivity above a few kilohertz, whereas the laser intensity did not significantly limit the detector sensitivity.
Excitons, bound electron-hole pairs, in Two-Dimensional Hybrid Organic Inorganic Perovskites (2D HOIPs) are capable of forming hybrid light-matter states known as exciton-polaritons (E-Ps) when the excitonic medium is...
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Background: Despite being the gold standard for diagnosing osteoporosis, dual-energy X-ray absorptiometry (DXA) is an underutilized screening tool for osteoporosis. Objectives: This study proposed and validated a cont...
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