Wave fields in the Bohai Sea are continuously simulated by the third-generation wave model SWAN in order to determine the wave energy resources from 1985 to 2010. The wind parameters used to simulate ...waves are obtained by the Regional Atmospheric Modeling System (RAMS). Comparisons of significant wave heights between simulations and observations show good agreement. The spatial distributions of mean monthly and annual averaged significant wave height and wave power flux are presented. Wave energy roses and temporal variations of average wave power density at five typical points in the Bohai Sea are calculated. Furthermore, the correlations between significant wave height and wave energy period are studied in scatter and energy diagrams.
•The SWAN model is used to investigate the wave energy resources in Bohai Sea, China.•The spatial distribution of mean annual averaged significant wave height is proposed.•Spatial distributions of wave power flux on a monthly basis are also analyzed.•Wave energy roses and temporal variations of average wave power density are given.•Combined scatter and energy diagrams of the annual energy are presented.
Artificial intelligence (AI)-based medical consumer electronics have attracted increasing attention in the fields of precision medicine and intelligent diagnosis. Accurately predicting ...echocardiographic parameters, such as the size of the left ventricular (LV) area and the ejection fraction (EF), is crucial for the precise diagnosis and treatment of cardiovascular diseases. However, limited data annotations are typically available for medical data, leading to substantial disparities among the segmentation accuracies obtained by deep learning models across different frames, and varying degrees of overfitting are observed in EF prediction tasks. In this work, a joint mask-augmented adaptive scale alignment (ASA) and periodicity-aware EF prediction method is proposed for cardiac function assessment. This approach enhances the accuracy and reliability of LV segmentation and EF prediction. First, an enhanced strategy is proposed to optimize LV segmentation to address the considerable segmentation accuracy variations across different frames. Second, variants of the ASA method are presented to perform regional alignment in EF prediction tasks, and an existing dataset is extended to address model overfitting. Third, a periodicity-aware method is proposed for EF and keyframe prediction, correcting the unfocused attention of the model for different periods and frames within the same video. Finally, experiments conducted on the EchoNet-Dynamic dataset show that our method achieves segmentation accuracy of 91.51% at end-diastole (ED) and 93.55% at end-systole (ES), surpassing previous methods by 1.12% and 0.59%, respectively. The mean absolute error (MAE) in the EF prediction task is 3.92, and the coefficient of determination (R2) is 0.822, demonstrating that our approach outperforms the current state-of-the-art methods.
Accurately evaluating and predicting the ground settlement during tunnel excavation are crucial for ensuring the stability of tunnel structures. However, the traditional methods always use ...representative (or average) values for deterministic analysis and rarely consider the spatial variability of soil properties. In this study, a probabilistic analysis of ground settlement under uncertain soil properties was performed based on random fields combined with the finite-difference method. The random fields of Young’s modulus and friction angle of multilayered soils were generated based on the Cholesky decomposition in a manner consistent with a specified numerical mesh. The effects of spatial variability and cross-correlation in random fields on the ground settlement were investigated in detail. The results demonstrate that spatially variable soils significantly influence the probability of failure, magnitude, and longitudinal profile of ground settlement in the vertical direction. It can be found that the allowable ground settlement of the limit state function also dominated the degree of the vertical scale of fluctuation on stability. Neglecting the cross-correlation between the two random fields results in an overestimation of the probability of failure compared with an independent analysis. Subsequently, the failure mechanisms of ground settlement in spatially random soils were discussed.
Due to high theoretical capacity, lithium sulfur (Li–S) batteries are regarded as aussichtsreich batteries for future energy storage devices. Several factors, such as low usage effectiveness of ...sulfur and “shuttle effect” of polysulfides, restrain the development of Li–S batteries. Porous sulfur carriers have been developed to remit these shortcomings to some extent. In this paper, a simple strategy is reported to prepare porous Ni3S2 hollow microspheres as sulfur hosts for Li–S batteries by an easy hydrothermal and calcination method. The as-fabricated Ni3S2/S cathodes present excellent cycling performance (959.7 mA h g−1 at 0.1 C after 100 cycles) as well as good rate property and cyclability (557.5 mA h g−1 at 1 C after 400 cycles). Such excellent energy storage properties can be ascribed to the unique hollow microsphere structure with high specific surface area, which is conducive to the capture of polysulfides during cycling. The study also provides a simple route to develop transition metal sulfide with hollow structures as superior sulfur hosts which may promote the development of various hollow structures for Li–S batteries application.
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•Porous Ni3S2 hollow microspheres are prepared as sulfur hosts for Li–S batteries.•Ni3S2/S exhibit good electrochemical performance as Li–S battery cathodes.•Porous Ni3S2 hollow structure is conducive to capture polysulfide.•Large specific surface area of electrode can well adapt volume change of S.
Cu xO(x = 1,2)/amorphous compounds have been successfully synthesized by chemical free dealloying and spontaneous oxidation method. Technological parameters, such as the acid concentration and ...dealloying time strongly influence the crystal type, size and morphology of coppery oxide. The further study shows that with the increase of HCl concentration, the surface coverage rate of Cu2O micro-flowers increases and the sizes of Cu2O micro-flowers get bigger. Moreover, it is observed that cracks are formed on the etched ribbon surface and plentiful Cu2O/CuO particles grow up from these crack walls if the dealloying time extends to long enough. Considering many fascinating properties of Cu2O/CuO particles and the amorphous alloy carrier, potential application fields of these amazing compounds will be developed in future.
Various secondary structures, for example, β-sheet hydrogen bonds formed by oligopeptides exhibiting high directionality and selectivity provide a new avenue to regulate optoelectronic performances ...of supramolecular assemblies constructed by π-conjugated chromophores. In this work, oligopeptide-perylene diimides (AUPDIs) are synthesized to generate β-sheet strands which guide the formation of chiral supramolecular polymers with a diversity of morphologies in combination with the π–π stacking even in aqueous media. Complex morphology transitions are successfully controlled by simply adjusting the water volume fraction in the binary solvent of water and tetrahydrofuran from spherical hollow aggregates to long helical nanowires and to short nanofibers. The mechanism of the assembly changes from cooperative to the isodesmic model relying on AUPDI concentrations. This originates from the transformation in the β-sheet that regulates profoundly the arrangement of the AUPDI molecules. Prominently efficient and positive electronic sensing to triethylamine for highly helical nanowires engenders due to the highly ordered helical arrangement within the nanowires, fourfold of the short nanofibers.
An interesting biomass-derived shape memory polymer (SMP) based on cross-linked poly(l-malic acid) (PMA), with reconfigurable permanent shape and tunable shape memory transition temperature (Ttrans), ...was developed in this work. The amorphous cross-linked network was constructed in PMA using eco-friendly 1,8-octanediol as the cross-linker through a catalyst-free two-step way. The relations between crosslinking density (d) and glass transition temperature (Tg), as well as the mechanical strengths of as-obtained cross-linked PMA (CPMA) were then evaluated. Both the strengths and the Ttrans are easily tunable by controlling curing times. Moreover, the permanent shape of CPMA is reconfigurable due to additional crosslinking in the heat treatment process. It also shows good diversity of processing approaches. This work is the first report to achieve good strengths on the biodegradable PMA and to activate its shape memory effect, opening up a window of application of PMA as the smart material or even as the common plastics.
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•Developing a green and very simple SMP based on the cross-linked PMA.•The permanent shape is reconfigurable because of the solid state plasticity.•Shape memory transition temperature is tunable by controlling curing times.
In this study, a sapphire-derived fiber (SDF)-based Fabry-Pérot interferometer (FPI) is proposed and experimentally demonstrated as a high-temperature sensor using the arc discharge crystallization ...process, forming a region with disordered mullite grains. This shows that the disordered mullite grains are related to the gradual temperature distribution during the arc discharge process, which results in a larger refractive index (RI) modulation of the SDF near the fusing area, forming a reflection mirror. An FPI was obtained by combining the optical fiber end facet. Considering the high-temperature resistance of the fiber, the fabricated FPI was used for high-temperature sensing. This shows that the device can operate at temperatures of up to 1200 °C with a sensitivity of 15.47 pm/°C, demonstrating that the proposed devices have potential applications in high-temperature environments.
With the aim of studying the properties of SBS/CR modified asphalt with CR directional distributed in SBS, SBS/CR composites were prepared in advance by method of melt blending in this work, and then ...the SBS/CR composite modified asphalts were prepared by the traditional wet process. The effect of the content of CR and the compatibility between SBS and CR on modified asphalts were discussed in details. The results show that the increasing blending temperature is conducive to improving the compatibility between SBS and CR, but it led to degradation of polymer modifiers. The hot storage stability of modified asphalt decreases with the growth content of CR, while increases with the increasing blending temperature. The conventional properties, elastoplastic relaxation behavior, temperature-sensitivity and rheological behaviors of modified asphalts were evaluated by the test of cyclic tension, rotational viscosity, dynamic shear rheometer (DSR) and blending beam rheometer (BBR). The results indicate that SBS combined with CR in advance have positive effect on the properties of modified asphalt, which is related to the directional distribution of CR and the improved compatibility between SBS and CR. Furthermore, the pre-blending of CR with SBS enhances the resistance of modified asphalts to thermal-oxidation aging. This work provides further guidance for understanding the modification mechanism of SBS/CR composite modified asphalt and improving the properties of SBS/CR modified asphalt.
•SBS/CR modified asphalt with CR selective distribution were prepared.•The distribution state of CR has impact on the properties of modified asphalt.•The pre-combined SBS and CR can improve the storage stability of modified asphalt.•The better compatibility between SBS and CR, the better performance of modified asphalt.
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