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13 pages, 4605 KiB  
Article
Toxicity of Piper hispidinervum Essential Oil to Callosobruchus maculatus and Cowpea Bean Quality
by Maria Suely Siqueira Ferraz, Lêda Rita D’Antonino Faroni, Adalberto Hipólito de Sousa, Fernanda Fernandes Heleno, Marcus Vinicius de Assis Silva and Ernandes Rodrigues de Alencar
Plants 2024, 13(22), 3148; https://doi.org/10.3390/plants13223148 - 9 Nov 2024
Viewed by 413
Abstract
Essential oils and their major compounds have been studied to protect stored grains, especially for the control of insects. In this context, this research aimed to investigate the fumigation and contact toxicities of the essential oil of Piper hispidinervum C. DC. (Piperaceae [...] Read more.
Essential oils and their major compounds have been studied to protect stored grains, especially for the control of insects. In this context, this research aimed to investigate the fumigation and contact toxicities of the essential oil of Piper hispidinervum C. DC. (Piperaceae) (sin. Piper hispidum Sw.) to Callosobruchus maculatus adult individuals and the effect on insect progeny. We also assessed the essential oil’s effect on stored-cowpea quality. The fumigation bioassay used essential oil at 14.3, 57.1, 100.0, 142.9, and 185.7 µL/L of air, whereas the contact bioassay tested concentrations of 60, 80, 100, 120, and 140 µL/kg. Insect mortality was appraised after four days (fumigation) or one day (contact). In turn, oviposition and emergence rates were evaluated after seven (fumigation) or fifty (contact) days of storage. Grain quality was also analyzed after 50 days of storage. Safrole was confirmed as the primary compound of the essential oil. P. hispidinervum essential oil proved its fumigant and contact toxicities to C. maculatus adult individuals. The concentrations lethal to 50 and 95% of the population were, respectively, 91.23 and 242.59 µL/L of air (fumigation) and 101.51 and 208.52 µL/kg of cowpeas (contact). In both application forms, C. maculatus oviposition and progeny rates declined with the increase in the essential oil concentration. Furthermore, cowpea bean quality was preserved even at sublethal doses. Full article
(This article belongs to the Special Issue Green Insect Control: The Potential Impact of Plant Essential Oils)
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<p>Toxicity by fumigation (<b>A</b>) and contact (<b>B</b>) of <span class="html-italic">P. hispidinervum</span> essential oil to adults of <span class="html-italic">C. maculatus</span> in cowpea beans.</p>
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<p><span class="html-italic">C. maculatus</span> oviposition and progeny rates in cowpea beans treated with <span class="html-italic">P. hispidinervum</span> essential oil by fumigation (<b>A</b>,<b>B</b>) and contact (<b>C</b>,<b>D</b>).</p>
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<p>Quality analyses of grains fumigated at different <span class="html-italic">P. hispidinervum</span> essential oil concentrations. (<b>A</b>) moisture content (w.b.), (<b>B</b>) mass loss, (<b>C</b>) germination, and (<b>D</b>) bulk density.</p>
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<p>Quality analyses of grains sprayed at different <span class="html-italic">P. hispidinervum</span> essential oil concentrations. (<b>A</b>) moisture content (w.b.), (<b>B</b>) mass loss, (<b>C</b>) germination, and (<b>D</b>) bulk density.</p>
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24 pages, 2843 KiB  
Article
Phytochemical Composition and Functional Properties of Brassicaceae Microgreens: Impact of In Vitro Digestion
by Ivana Šola, Valerija Vujčić Bok, Maja Popović and Sanja Gagić
Int. J. Mol. Sci. 2024, 25(21), 11831; https://doi.org/10.3390/ijms252111831 - 4 Nov 2024
Viewed by 484
Abstract
The aim of this study was to compare the concentration of phenolic compounds, glucosinolates, proteins, sugars and vitamin C between kohlrabi (Brassica oleracea var. acephala gongylodes), Savoy cabbage (B. oleracea sabauda), Brussels sprouts (B. oleracea gemmifera), cauliflower ( [...] Read more.
The aim of this study was to compare the concentration of phenolic compounds, glucosinolates, proteins, sugars and vitamin C between kohlrabi (Brassica oleracea var. acephala gongylodes), Savoy cabbage (B. oleracea sabauda), Brussels sprouts (B. oleracea gemmifera), cauliflower (B. oleracea botrytis), radish (Raphanus sativus) and garden cress (Lepidium sativum) microgreens for their antioxidant and hypoglycemic potential. In addition, we applied an in vitro-simulated system of human digestion in order to track the bioaccessibility of the selected phenolic representatives, and the stability of the microgreens’ antioxidant and hypoglycemic potential in terms of α-amylase and α-glucosidase inhibition after each digestion phase. Using spectrophotometric and RP-HPLC methods with statistical analyses, we found that garden cress had the lowest soluble sugar content, while Savoy cabbage and Brussels sprouts had the highest glucosinolate levels (76.21 ± 4.17 mg SinE/g dm and 77.73 ± 3.33 mg SinE/g dm, respectively). Brussels sprouts were the most effective at inhibiting protein glycation (37.98 ± 2.30% inhibition). A very high positive correlation (r = 0.830) between antiglycation potential and conjugated sinapic acid was recorded. For the first time, the antidiabetic potential of microgreens after in vitro digestion was studied. Kohlrabi microgreens best inhibited α-amylase in both initial and intestinal digestion (60.51 ± 3.65% inhibition and 62.96 ± 3.39% inhibition, respectively), and also showed the strongest inhibition of α-glucosidase post-digestion (19.22 ± 0.08% inhibition). Brussels sprouts, cauliflower, and radish had less stable α-glucosidase than α-amylase inhibitors during digestion. Kohlrabi, Savoy cabbage, and garden cress retained inhibition of both enzymes after digestion. Kohlrabi antioxidant capacity remained unchanged after digestion. The greatest variability was seen in the original samples, while the intestinal phase resulted in the most convergence, indicating that digestion reduced differences between the samples. In conclusion, this study highlights the potential of various microgreens as sources of bioactive compounds with antidiabetic and antiglycation properties. Notably, kohlrabi microgreens demonstrated significant enzyme inhibition after digestion, suggesting their promise in managing carbohydrate metabolism and supporting metabolic health. Full article
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Graphical abstract

Graphical abstract
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<p>Amount of (<b>A</b>) total glucosinolates, (<b>B</b>) proteins and (<b>C</b>) soluble sugars in Brassicaceae microgreens. Values represent mean ± standard deviation of three biological and three technical replicates. Different letters indicate a significant difference among the samples (ANOVA, Duncan test, <span class="html-italic">p</span> ≤ 0.05). SinE = sinigrin equivalent, BSAE = bovine serum albumin equivalent, GluE = glucose equivalent, dm = dry mass.</p>
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<p>Potential to inhibit protein glycation expressed in percentage of inhibition (%). Different letters indicate a significant difference among the values (ANOVA, Duncan test, <span class="html-italic">p</span> ≤ 0.05).</p>
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<p>Diagram (biplot) of Principal Component Analysis (PCA) of undigested microgreens based on their total and individual bioactive compounds, antiglycation and antioxidant potential. (<b>A</b>) Grouping of samples, (<b>B</b>) grouping of analyzed parameters. TP = total phenolics, TFlo = total flavonols, TT = total tannins, THCA = total hydroxycinnamic acids, SS = soluble sugars, Glucosinol = total glucosinolates, ABTS = antioxidant capacity measured by the method ABTS, FRAP = antioxidant capacity measured by the FRAP method, DPPH = antioxidant capacity measured by the DPPH method, Antiglic = antiglication potential, Vit C = vitamin C, Fer = ferulic acid, Sin = sinapic acid, Q = quercetin, K = kaempferol, TIPA = total identified phenolic acids, TIF = total identified flavonoids, TIP = total identified phenolics, TIC = total identified compounds, fc = free compound, cc = conjugated compound.</p>
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<p>Diagram (biplot) of Principal Component Analysis (PCA) of microgreens after (<b>A</b>) initial and (<b>B</b>) intestinal phase of digestion based on their total and individual bioactive compounds, antioxidant potential, and ability to inhibit enzymes α-amylase and α-glucosidase. (<span class="html-italic">i</span>) Grouping of samples, (<span class="html-italic">ii</span>) grouping of analyzed parameters. TP = total phenolics, TF = total flavonoids, ABTS = antioxidant capacity measured by the method ABTS, FRAP = antioxidant capacity measured by the FRAP method, DPPH = antioxidant capacity measured by the DPPH method, Fer = ferulic acid, Sin = sinapic acid, Q = quercetin, K = kaempferol, TIPA = total identified phenolic acids, TIF = total identified flavonoids, TIP = total identified phenolics, TIC = total identified compounds.</p>
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<p>Hierarchical clustering, expressed as Euclidean distance, of undigested microgreens, based on their total and individual bioactive compounds, antiglycation and antioxidant potential.</p>
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<p>Hierarchical clustering, expressed as Euclidean distance, of (<b>A</b>) undigested microgreens based on their total and individual bioactive compounds, antiglycation and antioxidant potential; and (<b>B</b>) microgreens after intestinal phase of digestion based on their total and individual bioactive compounds, antioxidant potential, and ability to inhibit enzymes α-amylase and α-glucosidase.</p>
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10 pages, 2586 KiB  
Article
AlGaN-Based Ultraviolet PIN Photodetector Grown on Silicon Substrates Using SiN Nitridation Process and Step-Graded Buffers
by Jian Li, Yan Maidebura, Yang Zhang, Gang Wu, Yanmei Su, Konstantin Zhuravlev and Xin Wei
Crystals 2024, 14(11), 952; https://doi.org/10.3390/cryst14110952 - 31 Oct 2024
Viewed by 401
Abstract
The integration of aluminum gallium nitride (AlGaN) with silicon substrates attracts significant attention due to the superior UV sensitivity of AlGaN and the cost-effectiveness as well as mechanical robustness of silicon. A PIN ultraviolet photodetector with a peak detection wavelength of 274 nm [...] Read more.
The integration of aluminum gallium nitride (AlGaN) with silicon substrates attracts significant attention due to the superior UV sensitivity of AlGaN and the cost-effectiveness as well as mechanical robustness of silicon. A PIN ultraviolet photodetector with a peak detection wavelength of 274 nm is presented in this paper. By employing a SiN nucleation layer and a step-graded buffer, a high-quality AlGaN-based photodetector structure with a dislocation density of 2.4 × 109/cm2 is achieved. A double-temperature annealing technique is utilized to optimize the Ohmic contact of the n-type AlGaN. The fabricated UV photodetector attains a dark current of 0.12 nA at −1 V and a peak responsivity of 0.12 A/W. Full article
(This article belongs to the Special Issue Crystal Growth of III–V Semiconductors)
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<p>(<b>a</b>) Scanning electron microscopy (SEM) cross-sectional image of the entire photodetector structure and microscope images under (<b>b</b>) 100× and (<b>c</b>) 1000×.</p>
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<p>Processing procedure and the microscope image of fabricated photodetectors.</p>
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<p>Cross-sectional TEM images of the step-graded AlGaN buffers: (<b>a</b>) STEM HAADF image, (<b>b</b>) dark field image of the Si/AlN interface, and (<b>c</b>) dark field image of the step-graded buffer. (Orange lines indicate the interface of different graded steps).</p>
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<p>Cross-sectional TEM images of the step-graded AlGaN buffers: (<b>a</b>) STEM HAADF image, (<b>b</b>) bend angle of the dislocation inclination at the different step interfaces, and (<b>c</b>) dislocation annihilation efficiency at different step interfaces. (orange lines indicate the interfaces of different graded steps and the yellow lines indicate the dislocation).</p>
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<p>IV profile under different annealing conditions. Inset: metal surface morphology deterioration under high-temperature long-time annealing.</p>
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<p>Responsivity and the IV curve of the fabricated photodetectors.</p>
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13 pages, 3686 KiB  
Communication
A Novel Robust Position Integration Optimization-Based Alignment Method for In-Flight Coarse Alignment
by Xiaoge Ning, Jixun Huang and Jianxun Li
Sensors 2024, 24(21), 7000; https://doi.org/10.3390/s24217000 - 31 Oct 2024
Viewed by 402
Abstract
In-flight alignment is a critical milestone for inertial navigation system/global navigation satellite system (INS/GNSS) applications in unmanned aerial vehicles (UAVs). The traditional position integration formula for in-flight coarse alignment requires the GNSS velocity data to be valid throughout the alignment period, which greatly [...] Read more.
In-flight alignment is a critical milestone for inertial navigation system/global navigation satellite system (INS/GNSS) applications in unmanned aerial vehicles (UAVs). The traditional position integration formula for in-flight coarse alignment requires the GNSS velocity data to be valid throughout the alignment period, which greatly limits the engineering applicability of the method. In this paper, a new robust position integration optimization-based alignment (OBA) method for in-flight coarse alignment is presented to solve the problem of in-flight alignment under a prolonged ineffective GNSS. In this methodology, to achieve a higher alignment accuracy in case the GNSS is not effective throughout the alignment period, the integration of GNSS velocity into the local-level navigation frame is replaced by the GNSS position in the Earth-centered, Earth-fixed frame, which avoids the need for complete GNSS velocity data. The simulation and flight test results show that the new robust position integration method proposed in this paper achieves higher stability and robustness than the conventional position integration OBA method and can achieve an alignment accuracy of 0.2° even when the GNSS is partially time-invalidated. Thus, this greatly extends the application of the OBA method for in-flight alignment. Full article
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<p><math display="inline"><semantics> <mrow> <msup> <mstyle mathvariant="bold" mathsize="normal"> <mi>x</mi> </mstyle> <mi>e</mi> </msup> </mrow> </semantics></math> at different moments.</p>
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<p>Diagram of the robust position integration formula method.</p>
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<p>(<b>a</b>) Simulation velocity; (<b>b</b>) simulation attitude; (<b>c</b>) simulation trajectory position.</p>
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<p>(<b>a</b>) Simulation velocity; (<b>b</b>) simulation attitude; (<b>c</b>) simulation trajectory position.</p>
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<p>Curves of the alignment attitude error of the two methods for the first simulation condition.</p>
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<p>Curves of the alignment attitude error of the two methods for the second simulation condition.</p>
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<p>(<b>a</b>) Flight attitude; (<b>b</b>) flight velocity; (<b>c</b>) flight trajectory.</p>
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<p>(<b>a</b>) Flight attitude; (<b>b</b>) flight velocity; (<b>c</b>) flight trajectory.</p>
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<p>Curves of the alignment attitude error of the TPIF method and RPIF method flight data.</p>
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19 pages, 5530 KiB  
Article
TopoSinGAN: Learning a Topology-Aware Generative Model from a Single Image
by Mohsen Ahmadkhani and Eric Shook
Appl. Sci. 2024, 14(21), 9944; https://doi.org/10.3390/app14219944 - 30 Oct 2024
Viewed by 550
Abstract
Generative adversarial networks (GANs) have significantly advanced synthetic image generation, yet ensuring topological coherence remains a challenge. This paper introduces TopoSinGAN, a topology-aware extension of the SinGAN framework, designed to enhance the topological accuracy of generated images. TopoSinGAN incorporates a novel, differentiable topology [...] Read more.
Generative adversarial networks (GANs) have significantly advanced synthetic image generation, yet ensuring topological coherence remains a challenge. This paper introduces TopoSinGAN, a topology-aware extension of the SinGAN framework, designed to enhance the topological accuracy of generated images. TopoSinGAN incorporates a novel, differentiable topology loss function that minimizes terminal node counts along predicted segmentation boundaries, thereby addressing topological anomalies not captured by traditional losses. We evaluate TopoSinGAN using agricultural and dendrological case studies, demonstrating its capability to maintain boundary continuity and reduce undesired loop openness. A novel evaluation metric, Node Topology Clustering (NTC), is proposed to assess topological attributes independently of geometric variations. TopoSinGAN significantly improves topological accuracy, reducing NTC index values from 15.15 to 3.94 for agriculture and 14.55 to 2.44 for dendrology, compared to the baseline SinGAN. Modified FID evaluations also show improved realism, with lower FID scores: 0.1914 for agricultural fields compared to 0.2485 for SinGAN, and 0.0013 versus 0.0014 for dendrology. The topology loss enables end-to-end training with direct topological feedback. This new framework advances the generation of topologically accurate synthetic images, with applications in fields requiring precise structural representations, such as geographic information systems (GIS) and medical imaging. Full article
(This article belongs to the Special Issue Advances and Applications of Complex Data Analysis and Computing)
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<p>TopoSinGAN’s multiresolution architecture.</p>
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<p>(<b>a</b>) The eight 3 × 3 convolution kernels employed in the topology enhancer loss. Dark pixels represent 1 s and 0 s otherwise. (<b>b</b>) The convolution kernels’ performance for topology loss. The output of the kernel convolution (highlighted points) is overlaid on the input tensor for better visualization.</p>
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<p>The architecture of the developed loss function.</p>
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<p>Illustration of defined terminal distance (TD) in a simple graph.</p>
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<p>The result of SVM graph classification using different feature sets.</p>
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<p>The outputs of the SinGAN and TopoSinGAN models trained on a single real image for agricultural fields and dendrology experiments. The red frame highlights the TopoSinGAN results, emphasizing the improved topological accuracy in comparison with SinGAN.</p>
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<p>Sample outputs generated by TopoSinGAN and other GAN models. The single input used for the SinGAN and TopoSinGAN training is displayed on the left, while WGAN and TopoGAN were trained using the CREMI dataset. The red frame highlights the outputs of the TopoSinGAN model, showcasing its topological consistency relative to other models.</p>
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<p>Tuning of the <math display="inline"><semantics> <msub> <mi>λ</mi> <mn>3</mn> </msub> </semantics></math> parameter for the CREMI experiment, showing its impact on FID (blue line) and NTC (red line). The best balance between FID and NTC is achieved at <math display="inline"><semantics> <mrow> <msub> <mi>λ</mi> <mn>3</mn> </msub> <mo>=</mo> <mn>0.4</mn> </mrow> </semantics></math> for this experiment.</p>
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<p>The seven extreme topological distributions of terminal nodes in a 15 × 15 2D grid, including random, dispersed, clustered, clustered-star, clustered-web, isolated edges, and randomly split-edge distributions.</p>
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16 pages, 14452 KiB  
Article
Disconnected Stationary Solutions in 3D Kolmogorov Flow and Their Relation to Chaotic Dynamics
by Nikolay M. Evstigneev, Taisia V. Karamysheva, Nikolai A. Magnitskii and Oleg I. Ryabkov
Mathematics 2024, 12(21), 3389; https://doi.org/10.3390/math12213389 - 30 Oct 2024
Viewed by 411
Abstract
This paper aims to investigate the nonlinear transition to turbulence in generalized 3D Kolmogorov flow. The difference between this and classical Kolmogorov flow is that the forcing term in the x direction sin(y) is replaced with [...] Read more.
This paper aims to investigate the nonlinear transition to turbulence in generalized 3D Kolmogorov flow. The difference between this and classical Kolmogorov flow is that the forcing term in the x direction sin(y) is replaced with sin(y)cos(z). This drastically complicates the problem. First, a stability analysis is performed by deriving the analog of the Orr–Sommerfeld equation. It is shown that for infinite stretching, the flow is stable, contrary to classical forcing. Next, a neutral curve is constructed, and the stability of the main solution is analyzed. It is shown that for the cubic domain, the main solution is linearly stable, at least for 0<R100. Next, we turn our attention to the numerical investigation of the solutions in the cubic domain. The main feature of this problem is that it is spatially periodic, allowing one to apply a relatively simple pseudo-spectral numerical method for its investigation. We apply the method of deflation to find distinct solutions in the discrete system and the method of arc length continuation to trace the bifurcation solution branches. Such solutions are called disconnected solutions if these are solutions not connected to the branch of the main solution. We investigate the influence of disconnected solutions on the dynamics of the system. It is demonstrated that when disconnected solutions are formed, the nonlinear transition to turbulence is possible, and dangerous initial conditions are these disconnected solutions. Full article
(This article belongs to the Special Issue Applied Mathematics in Nonlinear Dynamics and Chaos)
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<p>Neutral curve for the generalized Kolmogorov flow problem for <math display="inline"><semantics> <mrow> <mn>0.1</mn> <mo>≤</mo> <mi>α</mi> <mo>≤</mo> <mn>1</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <mn>2</mn> <mo>≤</mo> <mi>R</mi> <mo>≤</mo> <mn>30</mn> </mrow> </semantics></math>. Numbers near gray curves correspond to different values of wavenumbers <math display="inline"><semantics> <mrow> <msub> <mi>k</mi> <mi>x</mi> </msub> <mo>∈</mo> <mrow> <mo>{</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> <mo>,</mo> <mn>3</mn> <mo>}</mo> </mrow> </mrow> </semantics></math>, and the red curve is the hull of all wavenumbers such that the base solution is linearly stable above it and linearly unstable below it (as indicated in the figure).</p>
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<p>Verification of the bifurcation diagram of the base branch and disconnected branch that was found in [<a href="#B12-mathematics-12-03389" class="html-bibr">12</a>] for the 3D Kolmogorov flow problem with classical forcing and visualization of the branches in physical space by the absolute velocities isosurfaces (blue color represents lower magnitude, red color represents greater magnitude). Red dots represent solutions that were found by the process of deflation, black dots represent continuation of the solution trajectories, and <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> is the <math display="inline"><semantics> <msub> <mi>L</mi> <mn>2</mn> </msub> </semantics></math> norm in the solution in physical space. The saddle-point bifurcation at <math display="inline"><semantics> <mrow> <mi>R</mi> <mo>∼</mo> <mn>55.588</mn> </mrow> </semantics></math> forms a disconnected solution branch.</p>
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<p>Bifurcation diagram of stationary solutions and visualization of the branches in physical space by the absolute velocities isosurfaces (blue color represents lower magnitude, red color represents greater magnitude). Red dots represent solutions that were found by the process of deflation, black dots represent continuation of the solution trajectories, and <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> is the <math display="inline"><semantics> <msub> <mi>L</mi> <mn>2</mn> </msub> </semantics></math> norm in the solution in physical space. Zoomed area near the maximum parameter value in the neighborhood of the main solution branch.</p>
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<p>Bifurcation diagram and visualization of chaotic attractors. Attractor trajectories are represented in same norm <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> on the <span class="html-italic">y</span> axis and the value of the solution at the <math display="inline"><semantics> <msub> <mi>L</mi> <mn>1</mn> </msub> </semantics></math> norm on the <span class="html-italic">x</span> axis. Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the illustration on the bifurcation diagram.</p>
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<p>Bifurcation diagram and visualization of solutions at some points for <math display="inline"><semantics> <mrow> <mn>15.76</mn> <mo>≤</mo> <mi>R</mi> <mo>≤</mo> <mn>20</mn> </mrow> </semantics></math>. Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the solution visualization on the bifurcation diagram.</p>
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<p>Bifurcation diagram and visualization of the distance between disconnected branches and chaotic trajectory. The distance is measured in the Euclidean norm in the Fourier space by (<a href="#FD30-mathematics-12-03389" class="html-disp-formula">30</a>). Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the visualization on the bifurcation diagram.</p>
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<p>Bifurcation diagram and visualization of fifteen leading Lupunov exponents for some solutions. If a graph is not provided, then there are more than fifteen positive leading exponents for <math display="inline"><semantics> <mrow> <mi>R</mi> <mo>&gt;</mo> <mn>21</mn> </mrow> </semantics></math>. Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the illustration on the bifurcation diagram. Each subgraph displays evolution of leading Lyapunov exponents as a function of reorthogonalization iterations.</p>
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<p>Bifurcation diagram and visualization of solutions at some points for <math display="inline"><semantics> <mrow> <mn>21</mn> <mo>≤</mo> <mi>R</mi> <mo>≤</mo> <mn>22</mn> </mrow> </semantics></math>. Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the solution visualization on the bifurcation diagram.</p>
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<p>Bifurcation diagram and visualization of solutions at some points for <math display="inline"><semantics> <mrow> <mn>22</mn> <mo>≤</mo> <mi>R</mi> <mo>≤</mo> <mn>24</mn> </mrow> </semantics></math>. Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the solution visualization on the bifurcation diagram.</p>
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<p>Bifurcation diagram and visualization of solutions at some points for <math display="inline"><semantics> <mrow> <mi>R</mi> <mo>=</mo> <mn>26</mn> </mrow> </semantics></math>. Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the solution visualization on the bifurcation diagram.</p>
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<p>Bifurcation diagram and visualization of solutions at some points for <math display="inline"><semantics> <mrow> <mn>29</mn> <mo>≤</mo> <mi>R</mi> <mo>≤</mo> <mn>30</mn> </mrow> </semantics></math>. Vertical green segments represent the magnitude of the trajectories in <math display="inline"><semantics> <mrow> <mo>∥</mo> <mi>u</mi> <mo>∥</mo> </mrow> </semantics></math> norm and arrows represent the position of the solution visualization on the bifurcation diagram.</p>
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12 pages, 270 KiB  
Article
The Test of Sports and Folk Narratives with the Notion of Haram: Citing the Example of the Branch of Wrestling
by Ünsal Yılmaz Yeşildal, Doğukan Batur Alp Gülşen and Cihat Burak Korkmaz
Religions 2024, 15(11), 1311; https://doi.org/10.3390/rel15111311 - 26 Oct 2024
Viewed by 679
Abstract
Culture consists of material and spiritual values and tools that a nation has accumulated in the historical process. In addition to the most basic contexts such as language and religion, contexts such as sporting activities, art, public medicine, and the public calendar are [...] Read more.
Culture consists of material and spiritual values and tools that a nation has accumulated in the historical process. In addition to the most basic contexts such as language and religion, contexts such as sporting activities, art, public medicine, and the public calendar are also important environments that reveal their own cultural elements. Among these contexts, religion is very effective in shaping the daily life of the individual and, thus, society through the rules it enjoins. Religion does not dominate only the world of belief of the individual. Through the world of belief, it also directs their relations with the social institutions they are involved in. Sport is one of the most important activities and social institutions that stand out with various functions in daily life, with wrestling being one of the branches of sports that have emerged as a result of the imitation of the struggle of human beings with nature and other creatures with which they share nature. In particular, those involved in the nomadic way of life had to hunt in order not to starve and fight in order to survive. Wrestling, which emerged as a result of these obligations, held an important place among all Turks in the world for a period of time, especially in the transition periods of life, such as birth, marriage, and death. One of the conditions set forth by women as a condition of marriage was that their suitor defeated them in wrestling. Examples of this condition are also observed in literary texts belonging to different periods when Turks were not yet acquainted with Islam and the concepts of halal and haram, which entered their lives together with Islam. According to the provisions of the Holy Qur’an, right/unprohibited thoughts and actions are associated with the words good and halal, while wrong/prohibited thoughts and actions are associated with the words sin and haram. In this study, the social and cultural phases of wrestling as a sports branch among Turks in the historical process will be evaluated on the basis of the history of religions and religious references, in addition to the literary texts belonging to historical periods when Turks were members of different religions, in the context of two events that have been experienced and reported in the news. The study was carried out using the method of document analysis, a method of qualitative research, and the data obtained by this method were evaluated using content analysis. The narratives of Alıp Manaş, Alpamış, Alpamıs, Alıpmenşen, and Bamsı Beyrek, which are evaluated in this context, belong to the periods when the Turks had not been introduced to Islam or had only recently been introduced to it. Alıp Manaş was collated from different Turkic tribes such as the Altais, Alpamış from the Uzbeks, Alpamıs the Kazakhs/Karakalpaks, Alıpmenşen the Bashkirs/Tatars, and Bamsı Beyrek the Oghuz Turks. The narratives of Kirmanshah, Köse Kenan-Dânâ Hanım, Bey Böyrek, Shah Ismail, and Yaralı Mahmut, which are evaluated in the study, belong to the periods when the Turks became Muslim en masse, and are related only among the Oghuz Turks. These narratives are included in the study because they are similar to Alıp Manaş, Alpamış, Alpamıs, Alıpmenşen, and Bamsı Beyrek and they belong to the period when Islam was largely established among the Turkish masses in Anatolia. The effect of the new religion on wrestling, which is a branch of sport, will be revealed through these narratives belonging to different tribes and religious periods. Once more, an event that occurred in recent history, and was the subject of the news, was subjected to document analysis, and content analysis was carried out through the text of the news and evaluated in the context of the study. This study aims to explain the effect of religious rules on sports branches with theological, folkloric, and sociological references based on ancient literary texts belonging to the Turks and two incidents which were experienced. Full article
(This article belongs to the Special Issue Sport and Religion: Continuities, Connections, Concerns)
16 pages, 13038 KiB  
Article
Underwater Gyros Denoising Net (UGDN): A Learning-Based Gyros Denoising Method for Underwater Navigation
by Chun Cao, Can Wang, Shaoping Zhao, Tingfeng Tan, Liang Zhao and Feihu Zhang
J. Mar. Sci. Eng. 2024, 12(10), 1874; https://doi.org/10.3390/jmse12101874 - 18 Oct 2024
Viewed by 581
Abstract
Autonomous Underwater Vehicles (AUVs) are widely used for hydrological monitoring, underwater exploration, and geological surveys. However, AUVs face limitations in underwater navigation due to the high costs associated with Strapdown Inertial Navigation System (SINS) and Doppler Velocity Log (DVL), hindering the development of [...] Read more.
Autonomous Underwater Vehicles (AUVs) are widely used for hydrological monitoring, underwater exploration, and geological surveys. However, AUVs face limitations in underwater navigation due to the high costs associated with Strapdown Inertial Navigation System (SINS) and Doppler Velocity Log (DVL), hindering the development of low-cost vehicles. Micro Electro Mechanical System Inertial Measurement Units (MEMS IMUs) are widely used in industry due to their low cost and can output acceleration and angular velocity, making them suitable as an Attitude Heading Reference System (AHRS) for low-cost vehicles. However, poorly calibrated MEMS IMUs provide an inaccurate angular velocity, leading to rapid drift in orientation. In underwater environments where AUVs cannot use GPS for position correction, this drift can have severe consequences. To address this issue, this paper proposes Underwater Gyros Denoising Net (UGDN), a method based on dilated convolutions and LSTM that learns and extracts the spatiotemporal features of IMU sequences to dynamically compensate for the gyroscope’s angular velocity measurements, reducing attitude and heading errors. In the experimental section of this paper, we deployed this method on a dataset collected from field trials and achieved significant results. The experimental results show that the accuracy of MEMS IMU data denoised by UGDN approaches that of fiber-optic SINS, and when integrated with DVL, it can serve as a low-cost underwater navigation solution. Full article
(This article belongs to the Special Issue Autonomous Marine Vehicle Operations—2nd Edition)
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<p>Overview of the proposed method.The network denoises the raw IMU data to provide real-time compensation for the gyroscope output. During training, the network output is used to obtain the rotation increments for loss function. During testing, the denoised data are used as the input for the intergration to estimate the orientation, which is then integrated with DVL measurements to estimate the position of the navigation system.</p>
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<p>Network Architecture.</p>
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<p>Proposed dilated CNN−LSTM model structure for <math display="inline"><semantics> <msub> <mover accent="true"> <mi>ω</mi> <mo stretchy="false">˜</mo> </mover> <mi>n</mi> </msub> </semantics></math>.</p>
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<p>Data collecting platform.</p>
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<p>The experimental environment. (<b>a</b>) satellite photo; (<b>b</b>) natural scene.</p>
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<p>One sequence of our dataset, we set off from the dock, heading along the embankment deeper into the canyon.</p>
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<p>The overview of Orientation Estimation and <math display="inline"><semantics> <mrow> <mi>SO</mi> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </semantics></math> Orientation Error. In each subplot, the left part shows a comparison between the orientation estimated by these methods and the ground truth, while the right part displays the error between the estimated values and the ground truth, where (<b>a</b>) seq01; (<b>b</b>) seq03; (<b>c</b>) seq08.</p>
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<p>The overview of Orientation Estimation and <math display="inline"><semantics> <mrow> <mi>SO</mi> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </semantics></math> Orientation Error. In each subplot, the left part shows a comparison between the orientation estimated by these methods and the ground truth, while the right part displays the error between the estimated values and the ground truth, where (<b>a</b>) seq01; (<b>b</b>) seq03; (<b>c</b>) seq08.</p>
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<p>Comparisons of relative error between the proposed method and others, where (<b>a</b>) Seq06; (<b>b</b>) Seq05; (<b>c</b>) Seq02; (<b>d</b>) Seq09.</p>
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19 pages, 5466 KiB  
Communication
Study on the Robust Filter Method of SINS/DVL Integrated Navigation Systems in a Complex Underwater Environment
by Tianlong Zhu, Jian Li, Kun Duan and Shouliang Sun
Sensors 2024, 24(20), 6596; https://doi.org/10.3390/s24206596 - 13 Oct 2024
Viewed by 677
Abstract
This paper proposes an improved adaptive filtering algorithm based on the Sage–Husa adaptive Kalman filtering algorithm to address the issue of measurement noise characteristics impacting the navigation accuracy in strapdown inertial navigation system (SINS)/Doppler Velocity Log (DVL) integrated navigation systems. Addressing the non-positive [...] Read more.
This paper proposes an improved adaptive filtering algorithm based on the Sage–Husa adaptive Kalman filtering algorithm to address the issue of measurement noise characteristics impacting the navigation accuracy in strapdown inertial navigation system (SINS)/Doppler Velocity Log (DVL) integrated navigation systems. Addressing the non-positive definite matrix problem prevalent in traditional adaptive filtering algorithms and aiming to enhance measurement noise estimation accuracy, this method incorporates upper and lower thresholds determined by a discrimination factor. In the presence of abnormal measurement data, these thresholds are utilized to adjust the covariance of the innovation, subsequently re-estimating the system’s measurement noise through a decision factor based on the innovation. Simulation and experiment results demonstrate that the proposed improved adaptive filtering algorithm outperforms the classical Kalman filter (KF) in terms of navigation accuracy and stability. Furthermore, the filtering performance surpasses that of the Sage–Husa algorithm. The simulation results in this paper show that the relative position positioning error of the improved method is reduced by 49.44% compared with the Sage–Husa filtering method. Full article
(This article belongs to the Section Navigation and Positioning)
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<p>Hybrid calibration diagram of integrated navigation system.</p>
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<p>DVL error schematic diagram.</p>
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<p>Failure of DVL velocity measurement.</p>
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<p>Flowchart of improved adaptive filtering algorithm.</p>
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<p>Simulation trajectory diagram.</p>
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<p>Eastbound velocity and position error.</p>
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<p>Northbound velocity and position error.</p>
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<p>Horizontal velocity and position error.</p>
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<p>Trajectory comparison diagram of three navigation schemes.</p>
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<p>Eastbound velocity and position error in the second simulation.</p>
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<p>Northbound velocity and position error in the second simulation.</p>
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<p>Sprite E200D miniature AUV.</p>
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<p>Experimental preset trajectory.</p>
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<p>Comparison diagram of experimental trajectories.</p>
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21 pages, 6180 KiB  
Article
Adaptive Measurement and Parameter Estimation for Low-SNR PRBC-PAM Signal Based on Adjusting Zero Value and Chaotic State Ratio
by Minghui Lv, Xiaopeng Yan, Ke Wang, Xinhong Hao and Jian Dai
Mathematics 2024, 12(20), 3203; https://doi.org/10.3390/math12203203 - 12 Oct 2024
Viewed by 595
Abstract
Accurately estimating the modulation parameters of pseudorandom binary code–pulse amplitude modulation (PRBC–PAM) signals damaged by strong noise poses a significant challenge in emitter identification and countermeasure. Traditionally, weak signal detection methods based on chaos theory can handle situations with low signal-to-noise ratio, but [...] Read more.
Accurately estimating the modulation parameters of pseudorandom binary code–pulse amplitude modulation (PRBC–PAM) signals damaged by strong noise poses a significant challenge in emitter identification and countermeasure. Traditionally, weak signal detection methods based on chaos theory can handle situations with low signal-to-noise ratio, but most of them are developed for simple sin/cos waveform and cannot face PRBC–PAM signals commonly used in ultra-low altitude performance equipment. To address the issue, this article proposes a novel adaptive detection and estimation method utilizing the in-depth analysis of the Duffing oscillator’s behaviour and output characteristics. Firstly, the short-time Fourier transform (STFT) is used for chaotic state identification and ternary processing. Then, two novel approaches are proposed, including the adjusting zero value (AZV) method and the chaotic state ratio (CSR) method. The proposed weak signal detection system exhibits unique capability to adaptively modify its internal periodic driving force frequency, thus altering the difference frequency to estimate the signal parameters effectively. Furthermore, the accuracy of the proposed method is substantiated in carrier frequency estimation under varying SNR conditions through extensive experiments, demonstrating that the method maintains high precision in carrier frequency estimation and a low bit error rate in both the pseudorandom sequence and carrier frequency, even at an SNR of −30 dB. Full article
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<p>The measurement and estimation scenario of PRBC–PAM signal.</p>
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<p>Phase diagrams of chaotic and large−scale periodic states. (<b>a</b>) Chaotic state, <math display="inline"><semantics> <mrow> <mi>F</mi> <mo>=</mo> <mn>0.82</mn> <mo>&lt;</mo> <mn>0.826</mn> </mrow> </semantics></math> (<b>b</b>) large-scale periodic state, <math display="inline"><semantics> <mrow> <mi>F</mi> <mo>=</mo> <mn>0.83</mn> <mo>&gt;</mo> <mn>0.826</mn> </mrow> </semantics></math>.</p>
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<p>Time–output diagram of the intermittent chaotic state.</p>
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<p>Generation process of the PRBC–PAM signal.</p>
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<p>Waveform evolution process of the PAM pseudorandom sequence: (<b>a</b>) PRBC signal; (<b>b</b>) Pulse signal; (<b>c</b>) PAM pseudorandom sequence.</p>
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<p>The magnitude relationship between the equivalent driving force amplitude and the critical threshold of the duffing oscillator system: (<b>a</b>) <math display="inline"><semantics> <mrow> <msub> <mi>F</mi> <mi mathvariant="normal">e</mi> </msub> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> <mo>&gt;</mo> <msub> <mi>F</mi> <mi mathvariant="normal">c</mi> </msub> </mrow> </semantics></math>; (<b>b</b>) <math display="inline"><semantics> <mrow> <msub> <mi>F</mi> <mi mathvariant="normal">e</mi> </msub> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> <mo>&lt;</mo> <msub> <mi>F</mi> <mi mathvariant="normal">c</mi> </msub> </mrow> </semantics></math>.</p>
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<p>Three-dimensional time–frequency distribution diagram obtained by the STFT in three states: (<b>a</b>) Chaotic state; (<b>b</b>) Critical chaotic state; (<b>c</b>) Large-scale periodic state.</p>
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<p>Time-domain diagram of the STFT in three states: (<b>a</b>) Chaotic state; (<b>b</b>) Critical chaotic state; (<b>c</b>) Large-scale periodic state.</p>
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<p>Time−domain diagrams of the detection system driven by the PRBC-PAM signal: (<b>a</b>) Time-domain diagram of the input PAM’s sequence; (<b>b</b>) Time-domain diagram of the system output; (<b>c</b>) Time-domain diagram of <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>).</p>
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<p>Flow chart for the PRBC-PAM signal parameter estimation based on the Duffing oscillator.</p>
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<p>Time−domain diagram of the PAM pseudorandom sequence.</p>
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<p>Pseudo−random code time-domain diagram: (<b>a</b>) Pseudorandom code time-domain diagram obtained by <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>) with the AZV method; (<b>b</b>) Pseudorandom code time-domain diagram of the actual signal.</p>
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<p>Time-domain diagram of several signals when Δ<span class="html-italic">ω</span> ≠ 0: (<b>a</b>) detection system’s output; (<b>b</b>) <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>); (<b>c</b>) Estimated pseudorandom code after the AZV method; (<b>d</b>) Actual PAM pseudorandom sequence.</p>
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<p>Relational graph of Δ<span class="html-italic">ω</span> and <span class="html-italic">z</span><sub>m</sub>.</p>
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<p>The experimental layout and scenario: (<b>a</b>) The layout of the experimental setup; (<b>b</b>) The experimental scenario.</p>
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<p>NRMSE of the carrier frequency estimation of different methods under different SNRs [<a href="#B8-mathematics-12-03203" class="html-bibr">8</a>,<a href="#B10-mathematics-12-03203" class="html-bibr">10</a>,<a href="#B14-mathematics-12-03203" class="html-bibr">14</a>,<a href="#B15-mathematics-12-03203" class="html-bibr">15</a>,<a href="#B17-mathematics-12-03203" class="html-bibr">17</a>].</p>
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<p>Time−domain diagram of several signals under an SNR of 0 dB when <span class="html-italic">ω</span><sub>0</sub> = 100.03 MHz: (<b>a</b>) Output signal of the Duffing oscillator <span class="html-italic">y</span>(t); (<b>b</b>) Binarized signal <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>); (<b>c</b>) Estimated pseudorandom code; (<b>d</b>) Estimated PAM pseudorandom sequence.</p>
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<p>Time-domain diagram of several signals under an SNR of −10 dB when <span class="html-italic">ω</span><sub>0</sub> = 100.03 MHz: (<b>a</b>) Output signal of the Duffing oscillator <span class="html-italic">y</span>(t); (<b>b</b>) Binarized signal <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>); (<b>c</b>) Estimated pseudorandom code; (<b>d</b>) Estimated PAM pseudorandom sequence.</p>
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<p>Time-domain diagram of several signals under an SNR of −20 dB when <span class="html-italic">ω</span><sub>0</sub> = 100.03 MHz: (<b>a</b>) Output signal of the Duffing oscillator <span class="html-italic">y</span>(t); (<b>b</b>) Binarized signal <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>); (<b>c</b>) Estimated pseudorandom code; (<b>d</b>) Estimated PAM pseudorandom sequence.</p>
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<p>Time-domain diagram of several signals under an SNR of −25 dB when <span class="html-italic">ω</span><sub>0</sub> = 100.03 MHz: (<b>a</b>) Output signal of the Duffing oscillator <span class="html-italic">y</span>(t); (<b>b</b>) Binarized signal <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>); (<b>c</b>) Estimated pseudorandom code; (<b>d</b>) Estimated PAM pseudorandom sequence.</p>
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<p>Time-domain diagram of several signals under an SNR of −30 dB when <span class="html-italic">ω</span><sub>0</sub> = 100.03 MHz: (<b>a</b>) Output signal of the Duffing oscillator <span class="html-italic">y</span>(t); (<b>b</b>) Binarized signal <span class="html-italic">Sdf</span>(<span class="html-italic">t</span>); (<b>c</b>) Estimated pseudorandom code; (<b>d</b>) Estimated PAM pseudorandom sequence.</p>
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<p>Bit error rate for the PAM pseudorandom sequence of different method for different SNRs.</p>
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26 pages, 5289 KiB  
Article
Drimia maritima as a New Green Inhibitor for Al-Si Alloy, SAE Steel and Pure Al Samples in 0.5 M NaCl Solution: Polarization and Electrochemical Impedance Analyses
by Rodrigo S. Bonatti, Diego Costa, Giovana S. Padilha, Ausdinir D. Bortolozo and Wislei R. Osório
Metals 2024, 14(10), 1147; https://doi.org/10.3390/met14101147 - 8 Oct 2024
Viewed by 516
Abstract
The corrosion inhibition effects of Drimia maritima (L.) Stearn sin. Urginea maritima (L.) Backer on three different materials, i.e., as-cast Al-7 wt.% Si alloy, SAE 1020 low carbon steel, and commercially pure Al samples, into a stagnant and naturally aerated 0.5 M NaCl [...] Read more.
The corrosion inhibition effects of Drimia maritima (L.) Stearn sin. Urginea maritima (L.) Backer on three different materials, i.e., as-cast Al-7 wt.% Si alloy, SAE 1020 low carbon steel, and commercially pure Al samples, into a stagnant and naturally aerated 0.5 M NaCl solution are evaluated. For this purpose, both the potentiodynamic polarization curves and electrochemical impedance spectroscopy with an equivalent circuit are utilized. It is found that inhibition effect increases up to certain minor Drimia maritima content. Adsorption isotherms (e.g., Langmuir and Temkin) indicate that all three examined materials comprise physical adsorption mechanisms. Al-Si alloys attained inhibition efficiencies of about 96% at 25 °C with 1250 ppm of Drimia maritima and ~43% with 625 ppm at 45 °C. On the other hand, the cp. Al and SAE 1020 samples attain ~89% and 68% with 1250 ppm and 500 ppm at 25 °C, respectively. This clearly indicates that the dosage of Drimia maritima green inhibitor into NaCl solution possesses certain susceptibility for each distinctive material examined. Impedance parameters obtained by using CNLS (complex non-linear least squares simulations) are correlated and discussed. Full article
(This article belongs to the Special Issue Green Inhibitors for Metals Corrosion: Electrochemical Investigations)
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<p>Experimental results of the potentiodynamic polarization curves of the as-cast Al-7.5 wt.% Si alloy in a stagnant and naturally aerated 0.5 M NaCl solution at environmental temperature (25 ± 3 °C): (<b>a</b>) with absence of inhibitor <span class="html-italic">D. maritima</span>, (<b>b</b>) with 150 and 300 ppm, (<b>c</b>) containing 625 and 1250 ppm, and (<b>d</b>) showing 1250, 1875, and 100,000 ppm.</p>
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<p>Experimental results of the PP curves of the as-cast Al-7.5 wt.% Si alloy in a stagnant and naturally aerated 0.5 M NaCl solution comparing results at 25 (±3) and 45 (±3) °C in different concentrations: (<b>a</b>) 150 ppm, (<b>b</b>) 625 ppm, and (<b>c</b>) 1250 ppm.</p>
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<p>Experimental results of the PP curves of the as-cast Al-7.5 wt.% Si alloy in a stagnant and naturally aerated 0.5 M NaCl solution comparing results at 25 (±3) and 45 (±3) °C in different concentrations: (<b>a</b>) 150 ppm, (<b>b</b>) 625 ppm, and (<b>c</b>) 1250 ppm.</p>
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<p>Experimental EIS results of the Al-7.5 wt.% Si alloy in 0.5 M NaCl solution: (<b>a</b>) Bode and Bode-phase plots, (<b>b</b>) Nyquist diagrams comparing blank with distinctive concentrations, (<b>c</b>) and (<b>d</b>) showing duplicate for blank, and 150 and 1250 ppm comparisons, respectively; and (<b>e</b>,<b>f</b>) comparison among EIS plots of blank and 150, 625, and 1250 at 45 °C, also in a 0.5 M NaCl; and (<b>g</b>) the proposed equivalent circuit to obtain data EIS parameters using CNLS simulations.</p>
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<p>Experimental EIS results of the Al-7.5 wt.% Si alloy in 0.5 M NaCl solution: (<b>a</b>) Bode and Bode-phase plots, (<b>b</b>) Nyquist diagrams comparing blank with distinctive concentrations, (<b>c</b>) and (<b>d</b>) showing duplicate for blank, and 150 and 1250 ppm comparisons, respectively; and (<b>e</b>,<b>f</b>) comparison among EIS plots of blank and 150, 625, and 1250 at 45 °C, also in a 0.5 M NaCl; and (<b>g</b>) the proposed equivalent circuit to obtain data EIS parameters using CNLS simulations.</p>
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<p>Langmuir (<b>a</b>) Langmuir modified (<b>b</b>), Temkin adsorption isotherm plots at 25 and 45 °C; (<b>c</b>,<b>d</b>) Frumkim, (<b>e</b>) Flory–Huggins and (<b>f</b>) Freundlich isotherm plots at 25 °C; and (<b>g</b>) inhibition efficiency (in percentages) with a function of the DRIMIA concentration at 25 and 45 °C.</p>
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<p>Langmuir (<b>a</b>) Langmuir modified (<b>b</b>), Temkin adsorption isotherm plots at 25 and 45 °C; (<b>c</b>,<b>d</b>) Frumkim, (<b>e</b>) Flory–Huggins and (<b>f</b>) Freundlich isotherm plots at 25 °C; and (<b>g</b>) inhibition efficiency (in percentages) with a function of the DRIMIA concentration at 25 and 45 °C.</p>
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<p>A schematic representation of the inhibition behavior provided by DRIMIA (<span class="html-italic">D. maritima</span>) over a Al-Si alloy in NaCl solution. Hypothetical interactions between heteroatoms of DRIMIA compounds (physisorption) with Al and solvated cation, intermediate complex corrosion by-product (physisorption); and inhibitor with anion at surface of metal (chemisorption).</p>
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<p>Experimental EIS results and potentiodynamic polarization curves of: (<b>a</b>–<b>c</b>) the SAE 1020 low-carbon steel; and (<b>d</b>–<b>f</b>) the c.p. Al samples in 0.5 M NaCl solution at room temperature.</p>
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<p>Experimental EIS results and potentiodynamic polarization curves of: (<b>a</b>–<b>c</b>) the SAE 1020 low-carbon steel; and (<b>d</b>–<b>f</b>) the c.p. Al samples in 0.5 M NaCl solution at room temperature.</p>
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<p>(<b>a</b>) Langmuir, (<b>b</b>) Temkin adsorption isotherms plots at 25 °C; and (<b>c</b>) the resulting inhibition efficiency (in percentages) as a function of the DRIMIA concentrations at 25 °C.</p>
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14 pages, 1101 KiB  
Article
Advanced ENF Region Classification Using UniTS-SinSpec: A Novel Approach Integrating Sinusoidal Activation Function and Spectral Attention
by Yujin Li, Tianliang Lu, Gaojun Zeng, Kai Zhao and Shufan Peng
Appl. Sci. 2024, 14(19), 9081; https://doi.org/10.3390/app14199081 - 8 Oct 2024
Viewed by 599
Abstract
The electric network frequency (ENF), often referred to as the industrial heartbeat, plays a crucial role in the power system. In recent years, it has found applications in multimedia evidence identification for court proceedings and audio–visual temporal source identification. This paper introduces an [...] Read more.
The electric network frequency (ENF), often referred to as the industrial heartbeat, plays a crucial role in the power system. In recent years, it has found applications in multimedia evidence identification for court proceedings and audio–visual temporal source identification. This paper introduces an ENF region classification model named UniTS-SinSpec within the UniTS framework. The model integrates the sinusoidal activation function and spectral attention mechanism while also redesigning the model framework. Training is conducted using a public dataset on the open science framework (OSF) platform, with final experimental results demonstrating that, after parameter optimization, the UniTS-SinSpec model achieves an average validation accuracy of 97.47%, surpassing current state-of-the-art and baseline models. Accurate classification can significantly aid in ENF temporal source identification. Future research will focus on expanding dataset coverage and diversity to verify the model’s generality and robustness across different regions, time spans, and data sources. Additionally, it aims to explore the extensive application potential of ENF region classification in preventing crimes such as telecommunications fraud, terrorism, and child pornography. Full article
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<p>UniTS architecture.</p>
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<p>Illustration of activation functions.</p>
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<p>Comparison of activation function effects.</p>
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<p>Spectrum attention mechanism improvement diagram.</p>
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12 pages, 1677 KiB  
Article
Inhibitory Effects of Decursin Derivative against Lipopolysaccharide-Induced Inflammation
by Jinhee Lee, Jong-Beom Heo, Sanghee Cho, Chang-Woo Ryu, Hae-Joon Heo, Mi-Young Yun, Gaewon Nam, Gyu-Yong Song and Jong-Sup Bae
Pharmaceuticals 2024, 17(10), 1337; https://doi.org/10.3390/ph17101337 - 7 Oct 2024
Viewed by 730
Abstract
Background: This study aims to explore the protective role of JB-V-60—a novel synthetic derivative of decur-sin—against lipopolysaccharide (LPS)-induced inflammation. Methods: We examined the effects of JB-V-60 on heme oxygenase (HO)-1, cyclooxygenase (COX)-2, and inducible nitric oxide synthase (iNOS) in LPS-activated human pulmonary artery [...] Read more.
Background: This study aims to explore the protective role of JB-V-60—a novel synthetic derivative of decur-sin—against lipopolysaccharide (LPS)-induced inflammation. Methods: We examined the effects of JB-V-60 on heme oxygenase (HO)-1, cyclooxygenase (COX)-2, and inducible nitric oxide synthase (iNOS) in LPS-activated human pulmonary artery endothelial cells (HPAECs). Additionally, we assessed its effects on iNOS, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β in LPS-exposed mice. Results: JB-V-60 enhanced HO-1 levels, inhibited NF-κB activation, reduced COX-2/PGE2 and iNOS/NO concentra-tions, and lowered phosphorylation of signal transducer and activator of transcription 1. It also promoted the translocation of Nrf2 into the nucleus, allowing its binding to antioxidant response elements and resulting in reduced IL-1β in LPS-stimulated HPAECs. The reduction in iNOS/NO levels by JB-V-60 was reversed when HO-1 was inhibited via RNAi. In the animal model, JB-V-60 sig-nificantly decreased iNOS expression in lung tissues and TNF-α levels in bronchoalveolar lavage fluid. Conclusions: These findings highlight the anti-inflammatory effects of JB-V-60 and its potential as a treat-ment for inflammatory disorders. Full article
(This article belongs to the Section Pharmacology)
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<p>Structure and synthetic strategy of decursin derivative JB-V-60.</p>
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<p>JB-V-60 treatment in LPS-stimulated HPAECs reduces COX-2 and iNOS levels. The effect of JB-V-60 on cell viability was evaluated using the MTT assay (<b>A</b>). HPAECs were treated with LPS, followed by exposure to varying concentrations of JB-V-60 or Dex. iNOS protein (<b>B</b>,<b>C</b>), COX-2 protein (<b>C</b>), iNOS mRNA (<b>D</b>), COX-2 mRNA (<b>E</b>), NO (<b>F</b>), and PGE2 (<b>G</b>) levels were measured as the outcomes. Data are expressed as the mean ± SD from three independent experiments. * <span class="html-italic">p</span> &lt; 0.05 vs. LPS. Abbreviations: HPAECs, human pulmonary artery endothelial cells; LPS, lipopolysaccharide; COX-2, cyclooxygenase; iNOS, inducible nitric oxide synthase; NO, nitric oxide; PGE2, prostaglandin E2; SD, standard deviation.</p>
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<p>JB-V-60 inhibits the activities of NF-κB and STAT-1 while promoting an increase in HO-1 protein levels. In LPS-stimulated HPAECs, treatments with both JB-V-60 and Dex reduce NF-κB and STAT-1 activities and elevate HO-1 protein levels. (<b>A</b>) NF-κB activity was measured using the NF-κB luciferase reporter assay, (<b>B</b>) STAT-1 phosphorylation was assessed via ELISA, and (<b>C</b>) HO-1 levels were also quantified through ELISA. Results are presented as mean ± SD from three separate experiments. * <span class="html-italic">p</span> &lt; 0.05 vs. LPS. Abbreviations: HPAECs, human pulmonary artery endothelial cells; LPS, lipopolysaccharide; STAT-1, signal transducer and activator of transcription 1; HO-1, heme oxygenase; Dex, dexamethasone; NF, nuclear factor; ELISA, enzyme-linked immunosorbent assay; SD, standard deviation.</p>
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<p>In HPAECs, JB-V-60 promotes the nuclear translocation of Nrf2 and exhibits anti-inflammatory properties. (<b>A</b>) Exposure of HPAECs to various JB-V-60 concentrations, followed by the separation and analysis of cytosolic and nuclear fractions for Nrf2 levels via Western blot. (<b>B</b>) The activity of the ARE luciferase reporter was assessed in lysates from cells transfected with the ARE construct. (<b>C</b>–<b>E</b>) HO-1 was knocked down using siRNA, and IL-1β concentrations were measured using an ELISA kit. Results are presented as mean ± SD from three separate experiments. * <span class="html-italic">p</span> &lt; 0.05 vs. LPS, # <span class="html-italic">p</span> &lt; 0.05 vs. LPS + JB-V-60, or + <span class="html-italic">p</span> &lt; 0.05 vs. LPS + JB-V-60 + HO-1 siRNA. Abbreviations: HPAECs, human pulmonary artery endothelial cells; LPS, lipopolysaccharide; siRNA, small interfering RNA; HO-1, heme oxygenase; IL, interleukin; ARE, antioxidant response element; ELISA, enzyme-linked immunosorbent assay; NE, nuclear extract; CE, cytoplasmic extract; SD, standard deviation.</p>
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<p>In mice subjected to LPS injection, JB-V-60 effectively reduces TNF-α and iNOS levels while mitigating lung tissue damage. This involves an initial intraperitoneal LPS injection, followed by intravenous administration of JB-V-60 or Dex after 6 h. Lung tissues and BALF were collected 24 h post-LPS injection to assess protein levels of TNF-α (<b>A</b>) and iNOS (<b>B</b>), as well as mRNA levels of Nrf-2 (<b>E</b>) and HO-1 (<b>F</b>). The lung tissue was examined via H&amp;E staining (<b>C</b>), with histopathological scoring performed (<b>D</b>). Arrows indicate leukocyte infiltration. Additionally, the interaction between Keap1 and Nrf2 was analyzed using Co-IP (<b>G</b>). Results are expressed as mean ± SD from three independent experiments. * <span class="html-italic">p</span> &lt; 0.05 vs. LPS. Abbreviations: LPS, lipopolysaccharide; HO-1, heme oxygenase; Dex, dexamethasone; BALF, bronchoalveolar lavage fluid; iNOS, inducible nitric oxide synthase; Co-IP, co-immunoprecipitation; SD, standard deviation.</p>
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<p>Synthesis of decursin derivative 5 (JB-V-60)<b>.</b> Reagents and conditions; (a) Dess–Martin periodinane (1.5 equiv), CH<sub>2</sub>Cl<sub>2</sub>, 0 °C, 5 h; (b) (i) 4-methoxylbenzylamine (1.5 equiv), acetic acid (1.1 equiv), tetrahydrofuran (THF), room temperature (rt), 10 min; (ii) NaBH<sub>3</sub>CN (2 equiv), rt, 18 h; (c) 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (1.5 equiv), CH<sub>2</sub>Cl<sub>2</sub>, H<sub>2</sub>O, rt, 21 h; (d) trans-cinnamic acid (1.2 equiv), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) (1.4 equiv), triethylamine (TEA) (1.5 equiv), 4-dimethylaminopyridine (4-DMAP) (0.8 equiv), CH<sub>2</sub>Cl<sub>2</sub>, rt, 3 h.</p>
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23 pages, 12047 KiB  
Article
Autonomous Underwater Vehicle Navigation Enhancement by Optimized Side-Scan Sonar Registration and Improved Post-Processing Model Based on Factor Graph Optimization
by Lin Zhang, Lianwu Guan, Jianhui Zeng and Yanbin Gao
J. Mar. Sci. Eng. 2024, 12(10), 1769; https://doi.org/10.3390/jmse12101769 - 5 Oct 2024
Viewed by 712
Abstract
Autonomous Underwater Vehicles (AUVs) equipped with Side-Scan Sonar (SSS) play a critical role in seabed mapping, where precise navigation data are essential for mosaicking sonar images to delineate the seafloor’s topography and feature locations. However, the accuracy of AUV navigation, based on Strapdown [...] Read more.
Autonomous Underwater Vehicles (AUVs) equipped with Side-Scan Sonar (SSS) play a critical role in seabed mapping, where precise navigation data are essential for mosaicking sonar images to delineate the seafloor’s topography and feature locations. However, the accuracy of AUV navigation, based on Strapdown Inertial Navigation System (SINS)/Doppler Velocity Log (DVL) systems, tends to degrade over long-term mapping, which compromises the quality of sonar image mosaics. This study addresses the challenge by introducing a post-processing navigation method for AUV SSS surveys, utilizing Factor Graph Optimization (FGO). Specifically, the method utilizes an improved Fourier-based image registration algorithm to generate more robust relative position measurements. Then, through the integration of these measurements with data from SINS, DVL, and surface Global Navigation Satellite System (GNSS) within the FGO framework, the approach notably enhances the accuracy of the complete trajectory for AUV missions. Finally, the proposed method has been validated through both the simulation and AUV marine experiments. Full article
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<p>The framework of the proposed method.</p>
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<p>The original SSS image pairs: (a) The original SSS image 1; (b) The original SSS image 2.</p>
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<p>The result of classic Fourier-based image registration: (<b>a</b>) the PCM; (<b>b</b>) the overlapping.</p>
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<p>The result of registration optimized with Gaussian prior: (<b>a</b>) the PCM; (<b>b</b>) the overlapping; (<b>c</b>) the local area of the PCM; (<b>d</b>) the local area of the overlapping.</p>
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<p>The result of registration optimized with a bandpass filter: (<b>a</b>) the PCM; (<b>b</b>) the overlapping.</p>
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<p>The result of registration optimized with both a Gaussian prior and bandpass filter: (<b>a</b>) the PCM; (<b>b</b>) the overlapping; (<b>c</b>) the local area of the PCM; (<b>d</b>) the local area of the overlapping.</p>
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<p>Factor graph structure of proposed method.</p>
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<p>DVL installation angle.</p>
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<p>The trajectory comparison of different methods of the simulation.</p>
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<p>(<b>a</b>) Position error comparison of the simulation; (<b>b</b>) heading error comparison of the simulation.</p>
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<p>(<b>a</b>) Gyro bias estimation comparison; (<b>b</b>) Acc bias estimation comparison.</p>
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<p>Physical experiment setup. (<b>a</b>) The sensors equipped on the semi-submersible vehicle; (<b>b</b>) the semi-submarine vehicle’s trajectory (the red lines) and the SSS recording area.</p>
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<p>The trajectory comparison of different methods of marine experiments.</p>
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<p>(<b>a</b>) Position error comparison of marine experiments; (<b>b</b>) heading error comparison of marine experiments.</p>
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8 pages, 2033 KiB  
Article
Synergic Effect of N and Se Facilitates Photoelectric Performance in Co-Hyperdoped Silicon
by Haibin Sun, Xiaolong Liu, Caixia Xu, Long Xu, Yuwei Chen, Haima Yang, Xing Yang, Peng Rao, Shengli Sun and Li Zhao
Nanomaterials 2024, 14(19), 1591; https://doi.org/10.3390/nano14191591 - 2 Oct 2024
Viewed by 640
Abstract
Femtosecond-laser-fabricated black silicon has been widely used in the fields of solar cells, photodetectors, semiconductor devices, optical coatings, and quantum computing. However, the responsive spectral range limits its application in the near- to mid-infrared wavelengths. To further increase the optical responsivity in longer [...] Read more.
Femtosecond-laser-fabricated black silicon has been widely used in the fields of solar cells, photodetectors, semiconductor devices, optical coatings, and quantum computing. However, the responsive spectral range limits its application in the near- to mid-infrared wavelengths. To further increase the optical responsivity in longer wavelengths, in this work, silicon (Si) was co-hyperdoped with nitrogen (N) and selenium (Se) through the deposition of Se films on Si followed by femtosecond (fs)-laser irradiation in an atmosphere of NF3. The optical and crystalline properties of the Si:N/Se were found to be influenced by the precursor Se film and laser fluence. The resulting photodetector, a product of this innovative approach, exhibited an impressive responsivity of 24.8 A/W at 840 nm and 19.8 A/W at 1060 nm, surpassing photodetectors made from Si:N, Si:S, and Si:S/Se (the latter two fabricated in SF6). These findings underscore the co-hyperdoping method’s potential in significantly improving optoelectronic device performance. Full article
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<p>Scanning electron microscope (SEM) images of the (<b>a</b>) Si:N and (<b>b</b>) Si:N/Se at a laser fluence of 2.9 kJ/m2. The photos are viewed at 45° to the normal.</p>
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<p>(<b>a</b>) Absorptance spectra of planar Si reference and Si:N/Se samples with different Se precursor thickness, with different laser fluence; (<b>b</b>) reflectance spectra of the Si:N/Se samples with different Se precursor thickness; absorptance spectra of planar Si reference and Si:N/Se samples with different Se precursor thickness (<b>c</b>) before and (<b>d</b>) after rapid thermal annealing at 800 K for 5 min.</p>
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<p>Raman spectra of unannealed planar Si reference and Si:N/Se samples with different Se precursor thicknesses. A Si:N/Se sample with a 100 nm Se film precursor annealed at 875 K for 5 min and Si were given as compared. All hyperdoped Si samples were fabricated with a 4.0 kJ/m<sup>2</sup> laser fluence.</p>
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<p>(<b>a</b>) The schematic structure of hyperdoped Si photodetectors and the photoelectric responsivity measurement system. (<b>b</b>) The I-V characteristics of the photodetectors based on Si:N/Se with RAT at 725 K, 875 K and 1025 K for 5 min. (<b>c</b>) Spectral photoelectric responsivity of hyperdoped Si photodetectors and a commercial silicon photodetector used for calibration for comparison. (<b>d</b>) Responsivity gain (R–G) factors of the Si:N/Se vs. Si:N and Si:S/Se vs. Si:S.</p>
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