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  • MDPI AG  (27)
  • 1
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  Symmetry Vol. 14, No. 4 ( 2022-04-12), p. 800-
    In: Symmetry, MDPI AG, Vol. 14, No. 4 ( 2022-04-12), p. 800-
    Abstract: The discrete memristor has aroused increasing interest. In this paper, two discrete memristors with cosine with amplitude memristance are designed based on the discrete memristor model. The Simulink models of the two discrete memristors are built to verify that they meet the definition of the memristor. To improve the dynamic of a classic chaotic map, the discrete memristors are introduced into two chaotic maps: a Logistic map and a Hénon Map. Through the trajectory analysis, Lyapunov exponent, bifurcation diagram, and complexity analysis, it is shown that discrete memristors can indeed make the dynamical behaviors of chaotic maps richer and more complex.
    Type of Medium: Online Resource
    ISSN: 2073-8994
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2518382-5
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  • 2
    In: Coatings, MDPI AG, Vol. 13, No. 5 ( 2023-05-04), p. 868-
    Abstract: Moisture damage is one of the undesired distresses occurring in flexible asphalt pavements, mostly through water intrusion that weakens and ultimately degrades the asphalt mortar-aggregate interfacial bond. One method to mitigate this distress is using anti-stripping or anti-spalling filler materials that, however, require a systematic quantification of their interfacial bonding potential and moisture tolerance properties prior to wide-scale field use. With this background, this study was conducted to comparatively evaluate and quantitatively characterize the moisture sensitivity and water damage resistance of the interfacial bonding between the asphalt mortar and aggregate fillers. Using an in-house custom developed water-temperature coupling setup, numerous laboratory pull-out tests were carried out on the asphalt mortar with four different filler materials, namely limestone mineral powder, cement, slaked (hydrated) lime, and waste brake pad powder, respectively. In the study, the effects of moisture wet-curing conditions, temperature, and filler types were comparatively evaluated to quantify the water damage resistance of the asphalt mortar-aggregate filler interface. For interfacial microscopic characterization, the Image-Pro Plus software, 3-D digital imaging, and scanning electron microscope (SEM) were jointly used to measure the spalling rate and the surface micromorphology of the asphalt mortar and aggregate filler before and after water saturation, respectively. In general, the pull-out tensile force exhibited a decreasing response trend with more water damage and interfacial bonding decay as the moisture wet-curing temperature and time were increased. Overall, the results indicated superiority for slaked (hydrated) lime over the other filler materials with respect to enhancing and optimizing the asphalt mortar-aggregate interfacial bonding strength, moisture tolerance, and water damage resistance, respectively—with limestone mineral powder being the poorest performer.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662314-6
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  • 3
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  Remote Sensing Vol. 14, No. 16 ( 2022-08-19), p. 4055-
    In: Remote Sensing, MDPI AG, Vol. 14, No. 16 ( 2022-08-19), p. 4055-
    Abstract: Point cloud semantic segmentation, a challenging task in 3D data processing, is popular in many realistic applications. Currently, deep learning methods are gradually being applied to point cloud semantic segmentation. However, as it is difficult to manually label point clouds in 3D scenes, it remains difficult to obtain sufficient training samples for the supervised deep learning network. Although an increasing number of excellent methods have been proposed in recent years, few of these have focused on the problem of semantic segmentation with insufficient samples. To address this problem, this paper proposes a random graph based on graph convolution network, referred to as RG-GCN. The proposed network consists of two key components: (1) a random graph module is proposed to perform data augmentation by changing the topology of the built graphs; and (2) a feature extraction module is proposed to obtain local significant features by aggregating point spatial information and multidimensional features. To validate the performance of the RG-GCN, the indoor dataset S3DIS and outdoor dataset Toronto3D are used to validate the proposed network via a series of experiments. The results show that the proposed network achieves excellent performance for point cloud semantic segmentation of the two different datasets.
    Type of Medium: Online Resource
    ISSN: 2072-4292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2513863-7
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  • 4
    In: Materials, MDPI AG, Vol. 15, No. 6 ( 2022-03-19), p. 2281-
    Abstract: Wire mesh is a common material for bolt mesh supporting structures, but its application in engineering has revealed many defects. At the same time, with the development of new materials for civil engineering, the new material mesh performance and cost show outstanding advantages over wire mesh. In this paper, the feasibility of replacing wire mesh with steel-plastic geogrid as an alternative material is carefully studied through indoor tests and field applications. The following conclusions were drawn from a comparative analysis with wire mesh, mainly in terms of mechanical properties, engineering characteristics, and construction techniques: (1) in terms of mesh wire strength, wire mesh is slightly better than steel-plastic geogrid, but in the case of similar tensile strength, the amount of steel used per unit length of steel geogrid bars is only 36.75% of that of steel-plastic geogrid, while the tensile strength of the high-strength steel wire attached to the steel-plastic geogrid belt is about 3.3 times that of steel bars; (2) in terms of junction peel strength, both values are similar, with the injection-moulded junction being 1154.56–1224.38 N and the welded junction of 4 mm mesh being 988.35 N; (3) in terms of the strength of the mesh, steel-plastic geogrid is better than wire mesh, and with the same mesh wire strength, the bearing capacity of steel-plastic geogrid is increased by about 63.17% and the contribution of the mesh wire bearing capacity is increased by 83.66%, with the damage mainly being in the form of wire breakage in the ribbon causing ribbon failure, leading to further damage to the mesh; (4) in terms of the engineering application of steel-plastic geogrid compared to wire mesh, the utilization rate of mesh increases by about 24.99%, the construction efficiency increases by about 14.10%, and the economic benefit increases by about 45.31%. In practical application, the steel-plastic geogrid has good adhesion with surrounding rock and strong corrosion resistance. According to the above research analysis, the steel-plastic geogrid is feasible to replace the wire mesh for bolt mesh supporting.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2487261-1
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  • 5
    Online Resource
    Online Resource
    MDPI AG ; 2016
    In:  Sustainability Vol. 8, No. 2 ( 2016-02-22), p. 193-
    In: Sustainability, MDPI AG, Vol. 8, No. 2 ( 2016-02-22), p. 193-
    Type of Medium: Online Resource
    ISSN: 2071-1050
    Language: English
    Publisher: MDPI AG
    Publication Date: 2016
    detail.hit.zdb_id: 2518383-7
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  • 6
    Online Resource
    Online Resource
    MDPI AG ; 2018
    In:  Sustainability Vol. 10, No. 12 ( 2018-12-06), p. 4639-
    In: Sustainability, MDPI AG, Vol. 10, No. 12 ( 2018-12-06), p. 4639-
    Abstract: Destination image and safety not only affect tourist decision-making but also the sustainable development of tourist destinations. Some tourist destinations are too vulnerable to defend against emergency tourist crises, and tourists’ perceived safety can be severely biased, which is then deepened by media panic caused by the publication of excessive negative reports. This paper discusses the mechanism of perceived safety and perceived image on tourist behavioral intention, as well as the inter-group difference. Our study is based on a survey in Southern Xinjiang in which the respondents were divided into four groups. Four structural equation models were established with “perceived safety” and “perceived image” as independent variables, “destination trust” and “perceived value” as mediating variables, and “behavioral intention” as the dependent variable. The final results show that a paradox of safety perception exists in tourists’ perception of Southern Xinjiang. The perceived safety differs sharply between the tourists who have traveled to Southern Xinjiang and those who have not. The mechanism of perceived safety on tourist behavioral intention differs from that of the perceived image on tourist behavioral intention. Destination image still plays a key role in tourist traveling decision-making. The findings are of great significance for the restoration of cognitive bias, management, and marketing activities, and the sustainable development in Southern Xinjiang and similar destinations.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2518383-7
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  • 7
    In: Sustainability, MDPI AG, Vol. 15, No. 13 ( 2023-06-25), p. 10043-
    Abstract: Monitoring and restoring soil quality in areas neighboring roads affected by traffic activities require a thorough investigation of heavy metal concentrations. This study examines the spatial heterogeneity of copper (Cu) and chromium (Cr) concentrations in a 0.113 km² area adjacent to Jin-Long Avenue in Wuhan, China, using Unmanned Aerial Vehicle (UAV)-based hyperspectral remote sensing technology. Through this UAV-based remote sensing technology, we innovatively achieve a small-scale and fine-grained analysis of soil heavy metal pollution related with traffic activities, which represents a major contribution of this research study. In our approach, we generated 4375 spectral variates by transforming the original spectrum. To enhance result accuracy, we applied the Boruta algorithm and correlation analysis to select optimal spectral variates. We developed the retrieval model using the Gradient Boosting Decision Tree (GBDT) regression method, selected from a set of four regression methods using the LOOCV method. The resulting model yielded R-square values of 0.325 and 0.351 for Cu and Cr, respectively, providing valuable insights into the heavy metal concentrations. Based on the retrieved heavy metal concentrations from bare soil pixels (17,420 points), we analyzed the relationship between heavy metal concentrations and the perpendicular distance from the road. Additionally, we employed the universal kriging interpolation method to map heavy metal concentrations across the entire area. Our findings reveal that the concentration of heavy metals in this area exceeds background values and decreases as the distance from the road increases. This research significantly contributes to the understanding of spatial distribution characteristics and pollution caused by heavy metal concentrations resulting from traffic activities.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2518383-7
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  • 8
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  Symmetry Vol. 14, No. 11 ( 2022-11-12), p. 2393-
    In: Symmetry, MDPI AG, Vol. 14, No. 11 ( 2022-11-12), p. 2393-
    Abstract: For the co-saliency detection algorithm of an RGBD image that may have incomplete detection of common salient regions and unclear boundaries, we proposed an improved co-saliency detection method of RGBD images based on superpixels and hypergraphs. First, we optimized the depth map based on edge consistency, and introduced the optimized depth map into the SLIC algorithm to obtain the better superpixel segmentation results of RGBD images. Second, the color features, optimized depth features and global spatial features of superpixels were extracted to construct a weighted hypergraph model to generate saliency maps. Finally, we constructed a weighted hypergraph model for co-saliency detection based on the relationship of color features, global spatial features, optimized depth features and saliency features among images. In addition, in order to verify the impact of the symmetry of the optimized depth information on the co-saliency detection results, we compared the proposed method with two types of models, which included considering depth information and not considering depth information. The experimental results on Cosal150 and Coseg183 datasets showed that our improved algorithm had the advantages of suppressing the background and detecting the integrity of the common salient region, and outperformed other algorithms on the metrics of P-R curve, F-measure and MAE.
    Type of Medium: Online Resource
    ISSN: 2073-8994
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2518382-5
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  • 9
    In: Crystals, MDPI AG, Vol. 11, No. 11 ( 2021-10-31), p. 1328-
    Abstract: As a development on previous research on single crystals of Pr3+-doped yttria-stabilized zirconia (YSZ), we report here the preparation and optical properties of Yb/Pr co-doped YSZ single crystals with different Yb2O3 concentrations. Results from X-ray diffraction (XRD) and Raman spectroscopy indicated that all of the crystal samples had a cubic phase structure, and transmission was ≥88% in the 550–780 nm range. Photoluminescence (PL) under excitation with a 980 nm laser showed upconversion emission, and several peaks were observed centered on 448 nm, 508 nm, 525 nm, 542 nm, 617 nm and 656 nm. The effects of excited state absorption (ESA), energy transfer upconversion (ETU), cross relaxation (CR), and cooperative energy transfer (CET) on the upconversion luminescence and energy transition mechanism in YSZ crystals were further studied. The fluorescence lifetime of the 3P0 → 3H5 transition at 542 nm reached 207 μs, which shows that the samples are of potential use for laser and fluorescence output.
    Type of Medium: Online Resource
    ISSN: 2073-4352
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2661516-2
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  • 10
    In: Journal of Fungi, MDPI AG, Vol. 9, No. 4 ( 2023-04-16), p. 478-
    Abstract: Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) causes Fusarium wilt of banana, necessitating urgent measures to control this disease. However, the molecular mechanisms underlying Foc TR4 virulence remain elusive. Phosphomannose isomerase is a key enzyme involved in the biosynthesis of GDP mannose, an important precursor of fungal cell walls. In this study, two phosphomannose isomerases were identified in the Foc TR4 genome, of which only Focpmi1 was highly expressed throughout all developmental stages. Generated null mutants in Foc TR4 showed that only the ΔFocpmi1 mutant required exogenous mannose for growth, indicating that Focpmi1 is the key enzyme involved in GDP mannose biosynthesis. The Focpmi1 deficient strain was unable to grow without exogenous mannose and exhibited impaired growth under stress conditions. The mutant had reduced chitin content in its cell wall, rendering it vulnerable to cell wall stresses. Transcriptomic analysis revealed up- and down-regulation of several genes involved in host cell wall degradation and physiological processes due to the loss of Focpmi1. Furthermore, Focpmi1 was also found to be crucial for Foc TR4 infection and virulence, making it a potential antifungal target to address the threats posed by Foc TR4.
    Type of Medium: Online Resource
    ISSN: 2309-608X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2784229-0
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