3D object detection using lidar becomes essential for subsequent vehicle decision-making and planning as part of an intelligent vehicle perception system. Voxel RCNN is a two-stage voxel-based 3D ...object detection algorithm that is fast and accurate. However, the detection accuracy for specific categories is insufficient in complex traffic scenarios, thus we propose the Voxel RCNN-HA algorithm. First, in light of the shortcomings of Voxel RCNN in detecting pedestrians, a hybrid detection head is proposed to balance the advantages and disadvantages of anchor-based and anchor-free algorithms and significantly improve pedestrian detection performance while maintaining vehicle accuracy. Second, Self-Attention is introduced in the second stage of the algorithm and a Voxel Region of Interest (RoI) Self-Attention pooling module is developed to obtain both local and global features in RoI, which addresses the issue that the original Voxel RoI pooling module is challenging to obtain global features of large objects. On the One millioN sCEnes (ONCE) dataset, the proposed Voxel RCNN-HA achieves 66.79% mean Average Precision (mAP) and 11.7 Frames Per Second (FPS), outperforms both Voxel RCNN and CenterPoints in terms of detection accuracy. Additionally, experiments on Waymo Open dataset and Custom-Rslidar dataset further validate the effectiveness and generalization of the proposed method.
Prefabricated construction is one of the solutions to the problem of balancing environmental improvements with the new buildings in the construction industry. Some work originally done on site is ...transferred to the front end, and the occupational health risks to industrial workers during the production of prefabricate concrete components are thus aggravated. This study aims to propose a framework to simulate the occupational health risks of workers in prefabricate concrete component plants from the perspective of risk identification, risk assessment, and risk control. Through the following 4 steps, including environmental release monitoring, diffusion and human inhalation mechanism analysis, occupational health risk evaluation, and full-path health risk simulation, this study maps physical entities to virtual reality. The proposed method tends to address the root causes behind occupational health risks, such as the lack of measurement, assessment and prevention criteria, and providing new ideas for theoretical research and innovative practice of HSE management and risk management in the construction industry.
For hydrothermal liquefaction of dry biomass to produce liquid fuels, water needs to be added or the aqueous phase products can be recycled. This paper focuses on understanding the relationship ...between hydrothermal degradation of the dry biomass and oil formation under the condition of accumulative recycling of the aqueous phase. Completely dried corn stalk and deionized water were used for the hydrothermal liquefaction (HTL) experiment. The aqueous products for subsequent recycling were not diluted. It was demonstrated that the recycling of the aqueous can promote the enrichment of organic acids and the conversion of ketones and phenols in the aqueous, improving the yield and quality of Bio-crude oil. After recycling, the yield of Bio-crude oil increased from 20.42% to 24.31% continuously, and the oxygen content decreased from 13.34% to 9.90%. Although the process was accompanied by solid deposition and had a negative impact on the hydrothermal degradation efficiency, the formation of carbon microspheres during the deposition enhanced the utilization of nondegradable solids, while the formation of metal salt particles had a positive impact on oil production. After three rounds of recycling, the solid deposition effect was weakened. At this time, oil production and solids degradation can be promoted simultaneously.
Abstract
Background
In the emerging era of digitalization, eHealth literacy is of great importance in older adults’ health and social adaptation. Objective: Explore the effect of educational ...attainment on eHealth literacy among older adults and examine the mediating role of Internet experience and the moderating role of guidance on the Internet from family members to reveal the underlying mechanism. Method: Four hundred and ninety-one older adults (aged 59–76 years old, Mage = 65.69±4.41) completed the eHealth Literacy Scale (eHEALS) and Internet Experience among Older Adults Scale (IEOAS) and reported their educational attainment and the frequency of family members guiding them on how to use the Internet.
Results
eHealth literacy of older adults with lower educational attainment did not reach an intermediate level (M = 2.46±1.17). It was significantly lower than that of older adults with higher educational attainment whose scores were beyond the intermediate level (M = 3.43±0.90). Internet experience mediated the effect of older adults’ educational attainment on eHealth literacy. This mediation model was moderated by family members’ guidance on the Internet.
Discussion
our results have implications for understanding how educational attainment reinforced the inequality in eHealth literacy among older adults and how to address this gap. Specifically, If older adults with lower educational attainment are given guidance on Internet use by their family members frequently, they will no longer be at a disadvantage in accumulating Internet experience and further cultivate eHealth literacy to search for, distinguish, and take advantage of health information on the Internet well.
Instance-level tooth segmentation extracts abundant localization and shape information from panoramic radiographs (PRs). The aim of this study was to evaluate the performance of a mask refinement ...network that extracts precise tooth edges.
A public dataset which consists of 543 PRs and 16211 labelled teeth was utilized. The structure of a typical Mask Region-based Convolutional Neural Network (Mask RCNN) was used as the baseline. A novel loss function was designed focus on producing accurate mask edges. In addition to our proposed method, 3 existing tooth segmentation methods were also implemented on the dataset for comparative analysis. The average precisions (APs), mean intersection over union (mIoU), and mean Hausdorff distance (mHAU) were exploited to evaluate the performance of the network.
A novel mask refinement region-based convolutional neural network was designed based on Mask RCNN architecture to extract refined masks for individual tooth on PRs. A total of 3311 teeth were correctly detected from 3382 tested teeth in 111 PRs. The AP, precision, and recall were 0.686, 0.979, and 0.952, respectively. Moreover, the mIoU and mHAU achieved 0.941 and 9.7, respectively, which are significantly better than the other existing segmentation methods.
This study proposed an efficient deep learning algorithm for accurately extracting the mask of any individual tooth from PRs. Precise tooth masks can provide valuable reference for clinical diagnosis and treatment. This algorithm is a fundamental basis for further automated processing applications.
Magneto-optical (MO) properties of the bilayed Au/BIG and trilayered Au/BIG/Au magneto-plasmonic crystals (MPCs) were analyzed by the finite-difference time-domain method. In contrast to the low ...deflection angle and transmission of the smooth thin film, all the heterostructures with perforated holes in the top Au film displayed a similar trend with two strong resonant bands in Faraday rotation and transmittance in the near infrared wavelength range. The bands and electric distribution relative to the component and hole structure were revealed. The MPC with plasmonic hexagonal holes was found to own superior Faraday effects with distinctive anisotropy. The evolution of the resonant bands with the size and period of hexagonal holes, the thickness of different layers, and the incident light polarization was illustrated. The Faraday rotation of the optimized bilayed and trilayered hexagonal MPCs was improved 15.3 and 17.5 times, and the transmittance was enhanced 12.1 and 11.1 folds respectively at the resonant wavelength in comparison to the continuous Au/BIG film, indicating that the systems might find potential application in MO devices.
For the corrugated web steel beam, the web-to-flange welded detail by geometric discontinuity plays a vital role of the stress concentration-related fatigue fracture and failure mechanism. A study of ...the influences of the geometries of the crack-arrest hole on the stress intensity factor and related fracture behavior is presented in this research. The source of local stress concentration is investigated through finite element modeling and compared against experimentally measured strain results first to confirm the accuracy of analysis. Additional flank-holes symmetrically distributed on both sides of the crack tip are also considered for further reducing the crack driving force. The study shows that the introduction of the additional flank-hole is beneficial for further reduction of the stress concentration near the crack tip. Moreover, the inside of the crack-arrest hole is more efficient than the outside ones in reducing the stress intensity factor, while the use of bigger hole is recommended for the halting of short crack with the crack tip away from the edge of the flange. The further arrangement of the additional flank-hole within the crack seam range is beneficial in better reduction of the stress intensity factor for the models with the crack-arrest holes only. The shorter the distance of the additional flank-hole from the crack tip is, and the larger its radius is, the greater crack halting effect becomes.
To determine suitable cultivation measures to enrich selenium (Se) and alleviate the Se stress in fruit trees, the effects of different exogenous salicylic acid (SA) concentrations (0, 50, 100, 150 ...and 200 mg/L) on the growth and Se uptake of grapevine under Se stress were studied. Under Se stress, SA increased the biomass of grapevine to some extent and had a linear relationship with both root and shoot biomass. The chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance, and intercellular CO
2
concentration of grapevine tended to increase when the concentration of SA was < 150 mg/L and decrease when the concentration of SA was > 150 mg/L. Different concentrations of SA enhanced the activity of superoxide dismutase, while reducing that of peroxidase. It had no significant effect on the catalase activity of grapevine. SA decreased the content of osmotically active substances in grapevine to some extent. SA also increased the contents of total Se, inorganic Se and organic Se in grapevine to some extent, and had a linear or quadratic polynomial relationship with the total Se contents in both roots and shoots. When the SA concentration was 250 mg/L, the total Se contents in the roots and shoots were the highest and increased by 10.41% and 58.46%, respectively, compared with the control. Therefore, exogenous SA could promote the growth and Se uptake of grapevine under Se stress, with 250 mg/L serving as the most effective concentration.
Formation of regular micro/nano-structures on the surface of metallic glasses (MGs) is beneficial to their functional applications. To pattern the MG surface, in this work, a polished Zr-based MG ...sample was processed by using a nanosecond pulsed laser under various parameters. Experimental results showed that the regular leaf-shaped microstructure consisting of ripples and vein-like structures was generated in the irradiated area. The effects of processing parameters, including the average power, scanning speed, repetition frequency and pulse overlap rate, on the formation and evolution of leaf-shaped microstructure were investigated in detail. Furthermore, by analyzing the surface characteristics and morphological evolution, the formation mechanism of the leaf-shaped microstructure was analyzed. The ripples with spacing slightly smaller than the wavelength of incident laser were caused by interaction of the incident laser and excited molten surface waves, and the vein-like structures were formed by the subsequent laser pulses induced evolution of precedingly generated micro-cracks. The interaction between the ripples and the vein-like structures resulted in the formation of the leaf-shaped microstructure. After patterning, the MG surface with leaf-shaped microstructure showed enhanced hydrophilicity.
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•Nanosecond laser induced the leaf-shaped microstructure on metallic glass surface was reported.•Effects of laser parameters on the formation and evolution of leaf-shaped microstructure were investigated.•Formation mechanism of the leaf-shaped microstructure was discussed.•The laser processed MG surface with leaf-shaped microstructure exhibited enhanced hydrophilicity.
Magnesium matrix composites usually possess high strength and stiffness as well as low coefficient of thermal expansion, which makes them promising in lightweight and energy-saving strategies. ...Although the interfacial bonding state has a crucial influence on the properties of magnesium matrix composites, the interfacial reaction mechanism of Mg-RE alloy matrix composites is still unclear. Herein, the interfacial reaction and microstructure of Mg-10Gd-3Y-1Zn-0.4Zr (wt%) alloy matrix composite reinforced with aluminum borate whisker (Al18B4O33w) were reported by heating the matrix to a semisolid region and inducing the interfacial reaction to continue. After heat treatment at 600 °C for 6 h, the thickness of the interface layer increased from 50‐120 nm to about 335 nm, and the main interfacial reaction product was (Mg0.4Al0.6)Al1.8O4. With the increase of heating time to 12 h, a new double interface layer with (Mg0.4Al0.6)Al1.8O4 in the inner layer and MgO in the outer layer was formed. The difference of interfacial reaction products during isothermal heat treatment was related to the concentration gradient of Mg atoms along the radial direction of the whiskers and the hindrance of the migration of Mg atoms by reaction products formed in the early stage. These findings provide a further understanding of the interfacial reaction of Al18B4O33w reinforced Mg-RE alloy matrix composites.
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•High temperature treatment induced the interfacial reaction to continue.•Interfacial reaction products during isothermal heat treatment were identified.•Formation of products correlates with concentration and diffusion behavior of Mg.
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