Search

The main functions of the space information system, such as providing the backbone transmission, broadband access, and global connectivity, are realized based on the network topology. Thus, it is necessary to recognize the temporal dynamics of the network topology. A temporal continuity expression method is proposed to describe the topological dynamic characteristics of the network in space information systems. Based on orbit dynamics, a time-dependent adjacency matrix of the space information system can be established by introducing the geometric linkable factor, the link distance intensity factor, and the relative angular velocity factor of the node. The adjacency matrix describes the dynamic characteristics from two layers: one is the physical layer using a time-dependent function, which represents the feasibility of inter-satellite link construction in the system cycle; the other one is the transport layer, described by a piecewise continuous function that varies with time, which characterizes the link quality during the connection period between two satellites. The results show that compared with the existing network topology description methods, the proposed method describes the network topology more accurately, which can distinguish the network topology characteristics at any time, and is more conducive to the understanding and application of the network topology of the space information system. [ABSTRACT FROM AUTHOR]

Presently, the harm to human health created by air pollution has greatly drawn public attention, in particular, vehicle emissions including nitrogen oxides as well as particulate matter. How to predict air quality, e.g., pollutant concentration, efficiently and accurately is a core problem in environmental research. Developing a robust air quality predictive model has become an increasingly important task, holding practical significance in the formulation of effective control policies. Recently, deep learning has progressed significantly in air quality prediction. In this paper, we go one step further and present a neat scheme of masked autoencoders, termed as masked air modeling (MAM), for sequence data self-supervised learning, which addresses the challenges posed by missing data. Specifically, the front end of our pipeline integrates a WRF-CAMx numerical model, which can simulate the process of emission, diffusion, transformation, and removal of pollutants based on atmospheric physics and chemical reactions. Then, the predicted results of WRF-CAMx are concatenated into a time series, and fed into an asymmetric Transformer-based encoder–decoder architecture for pre-training via random masking. Finally, we fine-tune an additional regression network, based on the pre-trained encoder, to predict ozone (O   3 ) concentration. Coupling these two designs enables us to consider the atmospheric physics and chemical reactions of pollutants while inheriting the long-range dependency modeling capabilities of the Transformer. The experimental results indicated that our approach effectively enhances the WRF-CAMx model's predictive capabilities and outperforms pure supervised network solutions. Overall, using advanced self-supervision approaches, our work provides a novel perspective for further improving air quality forecasting, which allows us to increase the smartness and resilience of the air prediction systems. This is due to the fact that accurate prediction of air pollutant concentrations is essential for detecting pollution events and implementing effective response strategies, thereby promoting environmentally sustainable development. [ABSTRACT FROM AUTHOR]

Over recent decades, Landsat satellite data has evolved into a highly valuable resource across diverse fields. Long-term satellite data records with integrity and consistency, such as the Landsat series, provide indispensable data for many applications. However, the malfunction of the Scan Line Corrector (SLC) on the Landsat 7 satellite in 2003 resulted in stripping in subsequent images, compromising the temporal consistency and data quality of Landsat time-series data. While various methods have been proposed to improve the quality of Landsat 7 SLC-off data, existing gap-filling methods fail to enhance the temporal resolution of reconstructed images, and spatiotemporal fusion methods encounter challenges in managing large-scale datasets. Therefore, we propose a method for reconstructing dense time series from SLC-off data. This method utilizes the Neighborhood Similar Pixel Interpolator to fill in missing values and leverages the time-series information to reconstruct high-resolution images. Taking the blue band as an example, the surface reflectance verification results show that the Mean Absolute Error (MAE) and BIAS reach minimum values of 0.0069 and 0.0014, respectively, with the Correlation Coefficient (CC) and Structural Similarity Index Metric (SSIM) reaching 0.93 and 0.94. The proposed method exhibits advantages in repairing SLC-off data and reconstructing dense time-series data, enabling enhanced remote sensing applications and reliable Earth's surface reflectance data reconstruction. [ABSTRACT FROM AUTHOR]

Polyvinyl chloride microplastics (PVC-MPs) are microplastic pollutants widely present in the environment, but their potential risks to human lung health and underlying toxicity mechanisms remain unknown. In this study, we systematically analyzed the effects of PVC-MPs on the transcriptome and metabolome of BEAS-2B cells using high-throughput RNA sequencing and untargeted metabolomics technologies. The results showed that exposure to PVC-MPs significantly reduced the viability of BEAS-2B cells, leading to the differential expression of 530 genes and 3768 metabolites. Further bioinformatics analyses showed that PVC-MP exposure influenced the expression of genes associated with fluid shear stress, the MAPK and TGF-β signaling pathways, and the levels of metabolites associated with amino acid metabolism. In particular, integrated pathway analysis showed that lipid metabolic pathways (including glycerophospholipid metabolism, glycerolipid metabolism, and sphingolipid metabolism) were significantly perturbed in BEAS-2B cells following PVC-MPs exposure. This study provides new insights and targets for a deeper understanding of the toxicity mechanism of PVC-MPs and for the prevention and treatment of PVC-MP-associated lung diseases. [ABSTRACT FROM AUTHOR]

Water N-NO3− (mg L−1) pollution is attracting global concern in the face of combating climate change and human health risks. However, there have been comparatively few comprehensively researched studies on water N-NO3− pollution with respect to N-NO3− deposition, soil nitrogen, and land-use changes. We collected a total of 7707 published sampling points on N-NO3− surface and groundwater during flooding and non-flooding seasons during 2000–2020 in China. The types of water N-NO3− pollution (>20) can be categorized as point pollution (ΔTN ≤ 0 or > 1.5) and non-point pollution (0 < ΔTN ≤ 1.5), which were then assessed with respect to soil nitrogen (ΔTN g kg−1) and water N-NO3− changes in this study. We found non-point pollution was concentrated in the Huaihe River Basin and Haihe River Basin with higher urbanization (+6%, +4%), cropland (72%, 45%), nitrogen fertilization (g m−2 yr−1) (>10), and increased wet N-NO3− deposition (WND) (kg ha−1 yr−1) (+4.6, +3). The Haihe River Basin was found to have the highest N-NO3− on its surface (306) and in its groundwater (868) and nitrogen fertilization (32). Point pollution was concentrated in the Songhua and Liaohe River Basin with the highest WND (+7.9) but slow urbanization (+1%). N-NO3− increased during the flooding season compared with the no-flooding season in serious pollution areas. N-NO3− increased in the Liaohe River and middle and low Yangtze River but was reduced in the Weihe River. Therefore, stringent criteria and management, especially during the flooding season are urgently required to mitigate the degree of N-NO3− water pollution that occurs due to intensive agriculture and urbanization with increased N-NO3− deposition. [ABSTRACT FROM AUTHOR]

Targeting the issues of slow speed and inadequate precision of optimal solution calculation for multi-user detection in complex noise environments, this paper proposes a multi-user detection algorithm based on a Hybrid Cheetah Optimizer (HCO). The algorithm first optimizes the control parameters and individual update mechanism of the Cheetah Optimizer (CO) algorithm using a nonlinear strategy to improve the uniformity and discretization of the individual search range, and then dynamically introduces a differential evolutionary algorithm into the improved selection mechanism of the CO algorithm, which is utilized to fine-tune the solution space and maintain the local diversity during the fast search process. Simulation results demonstrate that this detection algorithm not only realizes fast convergence with a very low bit error rate (BER) at eight iterations but also has obvious advantages in terms of noise immunity, resistance to far and near effects, communication capacity, etc., which greatly improves the speed and accuracy of optimal position solving for multi-user detection and can achieve the purpose of accurate solving in complex environments. [ABSTRACT FROM AUTHOR]

Nonpoint source pollution (NPS) has become the most important reason for the deterioration of water quality, while relevant studies are often limited to African river and lake basins with insufficient data. Taking the Simiyu catchment of the Lake Victoria basin as the study area, we set up a NPS model based on the soil and water assessment tool (SWAT). Furthermore, the rationality of this model is verified with the field-measured data. The results manifest that: (1) the temporal variation of NPS load is consistent with the variation pattern of rainfall, the average monthly output of total nitrogen (TN) and total phosphorus (TP) in the rainy season was 1360.6 t and 336.2 t, respectively, while in the dry season was much lower, only 13.5 t and 3.0 t, respectively; (2) in view of spatial distribution among 32 sub-basins, TN load ranged from 2.051 to 24.288 kg/ha with an average load of 12.940 kg/ha, and TP load ranged from 0.263 to 8.103 kg/ha with an average load of 3.321 kg/ha during the 16-month study period; (3) Among the land use types, the cropland contributed the highest proportion of TN and TP pollution with 50.28% and 76.29%, respectively, while the effect of forest on NPS was minimal with 0.05% and 0.02% for TN and TP, respectively. (4) Moreover, the event mean concentration ( E M C ) values of different land use types have been derived based on the SWAT model, which are key parameters for the application of the long-term hydrological impact assessment (L-THIA) model. Therefore, this study facilitates applying the L-THIA model to other similar data-deficient catchments in view of its relatively lower data requirement. [ABSTRACT FROM AUTHOR]

Paralipsa gularis (Zeller) is a storage pest; however, in recent years it has evolved into a considerable maize pest during the late growth stage in the border region between China and other Southeast Asian countries. Bt transgenic insect-resistant maize is an effective measure in controlling a wide range of lepidopteran pests, but there is a lack of research on the toxic effects of storage pests. We tested the toxicity of Bt-Cry1Ab, Vip3Aa, and their complex proteins against P. gularis via bioassay and investigated the efficiency of Bt-(Cry1Ab+Vip3Aa) maize in controlling P. gularis during the late growth stage of maize in the period 2022–2023. The bioassay results show that the susceptibilities of P. gularis to the two Bt proteins and their complex proteins were significantly different. The LC50 values of DBNCry1Ab ("DBN9936" event), DBNVip3Aa ("DBN9501" event), DBN Cry1Ab+Vip3Aa ("DBN3601T" event), and Syngenta Cry1Ab+Vip3Aa ("Bt11" event × "MIR162" event) were 0.038 μg/g, 0.114 μg/g, 0.110 μg/g, and 0.147 μg/g, and the GIC50 values were 0.014 μg/g, 0.073 μg/g, 0.027 μg/g, and 0.026 μg/g, respectively. Determination of the expression content of the insecticidal protein in different tissues of Bt-(Cry1Ab+Vip3Aa) maize shows that the total Bt protein content in different tissues was in the following order: stalk > bract > cob > kernel. However, the bioassay results show that the mortalities of P. gularis feeding on Bt-(Cry1Ab+Vip3Aa) maize in different tissues at different growth stages were all above 93.00%. The field trial indicates that the occurrence density of larvae and plant damage rate for conventional maize were 422.10 individuals/100 plants and 94.40%, respectively, whereas no larvae were found on Bt-(Cry1Ab+Vip3Aa) maize. In summary, this study implies that Bt-(Cry1Ab+Vip3Aa) maize has a high potential for control of P. gularis, providing a new technical measure for the management of the pest. [ABSTRACT FROM AUTHOR]

Solid-state distillation is a distinctive process for extracting the baijiu aroma compounds that determine the flavor character of baijiu. In this study, the changes in various chemical properties of the aroma compounds in three classical Jiangxiangxing baijiu fermented grain distillation processes were analyzed. The changes in the aroma compounds in the instantaneous distillates were quantified and correlation analyzes were conducted. The results showed that the effect of the aroma compounds was greater than the differences between the fermented grains. Eleven representative aroma compounds were selected to develop the kinetic models describing two opposing changes. For the regulation of the Jiangxiangxing baijiu aroma compounds, their recovery rates were calculated using a kinetic model. A comprehensive comparison of the recovery rates of the characteristic aroma and other aroma compounds at different cut-off values revealed that the optimum recovery rate of the characteristic aroma of Jiangxiangxing baijiu 2,3,5,6-tetramethylpyrazine was 14.53% at cut-off values of 3.9 and 19.8 min. In this study, representative changes in the aroma compounds and the selection of cut-off values to regulate the baijiu distillation aroma were proposed. [ABSTRACT FROM AUTHOR]

The incorporation of rare earth oxides and nano-silica has been found to significantly enhance the mechanical and tribological characteristics of phenolic-based hybrid nanocomposites. In this work, the impact of these additives was investigated through single-factor experiments. The study revealed that cerium oxide and yttrium oxide were the primary factors influencing changes in the impact strength, shear strength, coefficient of friction, and wear rate. Additionally, the content of nano-silica exerted the most substantial influence on the hardness and compressive strength of the specimens. Furthermore, the material ratios of the phenolic-based hybrid nanocomposites were optimized using an orthogonal experimental design and a fuzzy comprehensive evaluation method. The optimal material ratio for these nanocomposites was determined to be 2% cerium oxide, 2.5% yttrium oxide, and 3% nano-silica, based on their mechanical, frictional, and wear properties. This research provides valuable insights for the development of new brake friction materials with low friction and high wear resistance and contributes to meeting the demand for polymer composites with superior mechanical performance in diverse applications. [ABSTRACT FROM AUTHOR]

The plasma spray method is widely utilized for enhancing wear, surface fatigue, and corrosion properties through coating. The mechanical and surface characteristics of the resulting coating are contingent upon various spraying parameters, including arc current, working current, spraying distance, and plasma gun traversing speed. This study investigates the impact of these manufacturing parameters on the porosity, hardness, and bond strength of a coating produced from an Al-Ni alloy applied to a Q235 steel substrate. An extensive experimental program was conducted to analyze the influence of these parameters on the coating properties. Consequently, a preferred combination of parameters, identified through a comprehensive evaluation method, yielded greater performance benefits compared to the orthogonal experimental groups. [ABSTRACT FROM AUTHOR]

In response to the problem of vibration and noise reduction in equipment with cylindrical shell structures, this paper focuses on the micro-perforated laminated cylindrical shell structure and establishes its finite element model. Through comparative analysis with experimental results, the reliability of the finite element modeling method is verified. Based on this, the paper places particular emphasis on the vibration and acoustic radiation performance of the structure in the 1–1000 Hz frequency range under free conditions to understand the impact of different laminated shell structures, micro-perforation parameters (porosity, aperture), sound-absorbing foam materials, and placement methods. The results indicate that micro-perforated structures can efficiently reduce the structural radiated sound power level at specific frequencies, but the overall reduction in radiated sound power level is not significant. Various types of foam are effective in reducing the structural radiation acoustic power level, with polyurethane performing best among them. Changing the location of foam placement has a relatively insignificant impact on the structural radiation acoustic power level. [ABSTRACT FROM AUTHOR]

Castanopsis is one of the most common genus of trees in subtropical evergreen broad-leaved forests and tropical monsoon rainforests in China. Castanopsis hainanensis and Castanopsis wenchangensis are endemic to Hainan Island, but they were once confused as the same species due to very similar morphologies. In this study, nuclear microsatellite markers and chloroplast genomes were used to delimit C. hainanensis and C. wenchangensis. The allelic variations of nuclear microsatellites revealed that C. hainanensis and C. wenchangensis were highly genetically differentiated with very limited gene admixture. Both showed higher genetic diversity within populations and lower genetic diversity among populations, and neither had further population genetic structure. Furthermore, C. wenchangensis and C. hainanensis had very different chloroplast genomes. The independent genetic units, very limited gene admixture, different distribution ranges, and distinct habitats all suggest that C. wenchangensis and C. hainanensis are independent species, thus they should be treated as distinct conservation units. [ABSTRACT FROM AUTHOR]

Temperature is a crucial environmental factor that affects embryonic development, particularly for marine organisms with long embryonic development periods. However, the sensitive period of embryonic development and the role of autophagy/apoptosis in temperature regulation in cephalopods remain unclear. In this study, we cultured embryos of Sepiella japonica, a typical species in the local area of the East China Sea, at different incubation temperatures (18 °C, 23 °C, and 28 °C) to investigate various developmental aspects, including morphological and histological characteristics, mortality rates, the duration of embryonic development, and expression patterns of autophagy-related genes (LC3, BECN1, Inx4) and apoptosis marker genes (Cas3, p53) at 25 developmental stages. Our findings indicate that embryos in the high-temperature (28 °C) group had significantly higher mortality and embryonic malformation rates than those in the low-temperature (18 °C) group. Furthermore, high temperature (28 °C) shortened the duration of embryonic development by 7 days compared to the optimal temperature (23 °C), while low temperature (18 °C) caused a delay of 9 days. Therefore, embryos of S. japonica were more intolerant to high temperatures (28 °C), emphasizing the critical importance of maintaining an appropriate incubation temperature (approximately 23 °C). Additionally, our study observed, for the first time, that the Early blastula, Blastopore closure, and Optic vesicle to Caudal end stages were the most sensitive stages. During these periods, abnormalities in the expression of autophagy-related and apoptosis-related genes were associated with higher rates of mortality and malformations, highlighting the strong correlation and potential interaction between autophagy and apoptosis in embryonic development under varying temperature conditions. [ABSTRACT FROM AUTHOR]

In March 2022, a new wave of COVID-19 outbreak occurred in Shanghai due to the widespread transmission of the Omicron variant. A two-month citywide lockdown was implemented from April 1st to May 31st, adopting measures such as zone-based classification and grid management. This unique social event provided an "ideal air quality experiment" for pollution research. The rapid reduction in economic activities during the lockdown had many positive impacts on the environment, leading to overall improvements in air quality. Particularly, the concentration of NOx, one of the precursors to O3, significantly decreased. However, O3, as a typical secondary pollutant, showed a noticeable increase. This study uses the WRF-CAMx-OSAT air quality model method to analyze the source of O3 pollution in Shanghai from April to May 2022. The impact of O3 precursor control, sector sources, and regional contributions on the formation of O3 pollution in Shanghai is analyzed in depth. During the pandemic lockdown period, it was found that, in Shanghai, the overall O3 levels were controlled by VOCs (Volatile Organic Compounds), and controlling VOCs proved to be an effective measure in reducing O3 concentrations in Shanghai. Compared with the same period in 2021, the proportion of road traffic sources contributing to ozone concentration has significantly decreased from 70.61% to 64.3%, but they are still the largest contributor. The contribution of industrial emissions to the ozone concentration has significantly risen from 20.71% to 26.36%, making them still the second largest contributor. Industrial and traffic sources are emission sources that require particular attention. The contribution ratio of local sources to external transport is about 7:3, which is higher than the ratio of local sources to external transport in the same period of 2021, which is about 6:4. The local ozone is the main source of ozone concentration in Shanghai, and controlling local source emissions is the key to controlling ozone concentration in the Shanghai area. When excluding the impact of long-range transport, the main areas contributing to O3 formation from local sources are Baoshan District, Jiading District, Qingpu District, and Chongming District, accounting for approximately 41.12% of the total absolute contribution. Different source regions exhibit significant spatial variations in their contributions to the ozone concentration. Through these studies, we aim to provide scientific support and control suggestions for the precise prevention and control of O3 pollution in Shanghai. [ABSTRACT FROM AUTHOR]

SiC particle (SiCp) size has been found to significantly influence the hot workability of particle-reinforced aluminum matrix composites (AMC). In this work, therefore, three types of SiCp/6013 composites with different SiCp sizes (0.7, 5 and 15 μm) were prepared and then subjected to isothermal hot compression tests. In addition, constitutive analysis, processing maps and microstructural characterizations were used to reveal the influence of SiCp size on the hot workability of SiCp/6013 composite. The results showed that the values of hot deformation activation energy Q increased with decreasing SiCp size. Specifically, at lower temperatures (e.g., 350 and 400 °C), the highest peak stress was shown in the AMC with SiCp size of 0.7 μm (AMC-0.7), while in the AMC with SiCp size of 5 μm (AMC-5) at higher temperatures (e.g., 450 and 500 °C). This is because a finer SiCp size would lead to stronger dislocation pinning and grain refinement strengthening effects, and such effects would be weakened at higher temperatures. Further, dynamic softening mechanisms were found to transform from dynamic recovery to dynamic recrystallization with increasing SiCp size, and the dynamic recrystallization occurred more easily at higher temperatures and lower strain rates. Consequently, the instability zones of the composites are all mainly located in the deformation region with lower temperature and higher strain rate, and smaller SiCp results in larger instability zones. [ABSTRACT FROM AUTHOR]

The microstructures and mechanical properties of Mg–3Sn–0.1Ca–xMM (mischmetal, x = 0.3, 0.6, and 0.9 wt.%) alloys were investigated. Optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD) were used to characterize the microstructures and phase constitutions of the cast and rolled alloys. Room temperature tensile tests were conducted to obtain the mechanical properties and macro-textures to evaluate the texture weakening effect results of the MM. The results show that an abundance of second phase formed, confirmed as the (Ca,MM)MgSn phase, and the volume fraction increased with the increasing MM addition. The tensile yield strength of the as-cast alloys increased with the MM addition, but the elongation decreased. All of the rolled Mg–3Sn–0.1Ca–xMM alloys showed a strong basal texture, and only slightly decreased in intensity after annealing treatment due to the particle-stimulated nucleation of recrystallization. The as-annealed Mg–3Sn–0.1Ca–0.6MM alloys exhibited the highest tensile strengths of 266.5 ± 3.3 MPa and 136.1 ± 3.7 MPa, which are mainly ascribed to grain refinement strengthening, Orowan strengthening and texture strengthening. [ABSTRACT FROM AUTHOR]

The combination of a blood cell analyzer and artificial microscopy to detect white blood cells is used in hospitals. Blood cell analyzers not only have large throughput, but they also cannot detect cell morphology; although artificial microscopy has high accuracy, it is inefficient and prone to missed detections. In view of the above problems, a method based on Fourier ptychographic microscopy (FPM) and deep learning to detect peripheral blood leukocytes is proposed in this paper. Firstly, high-resolution and wide-field microscopic images of human peripheral blood cells are obtained using the FPM system, and the cell image data are enhanced with DCGANs (deep convolution generative adversarial networks) to construct datasets for performance evaluation. Then, an improved DETR (detection transformer) algorithm is proposed to improve the detection accuracy of small white blood cell targets; that is, the residual module Conv Block in the feature extraction part of the DETR network is improved to reduce the problem of information loss caused by downsampling. Finally, CIOU (complete intersection over union) is introduced as the bounding box loss function, which avoids the problem that GIOU (generalized intersection over union) is difficult to optimize when the two boxes are far away and the convergence speed is faster. The experimental results show that the mAP of the improved DETR algorithm in the detection of human peripheral white blood cells is 0.936. In addition, this algorithm is compared with other convolutional neural networks in terms of average accuracy, parameters, and number of inference frames per second, which verifies the feasibility of this method in microscopic medical image detection. [ABSTRACT FROM AUTHOR]

In order to achieve the synthesis of contracted graphs (CGs) automatically by given associated linkages (ALs), a new feature description method is proposed and a software is constructed. First of all, a connection method substring (CMS) is proposed and the related guidelines are given. The combination of characteristic strings (CSs) and CMSs can accurately describe the type, number, and connection relationship between the basic links in a CG. Secondly, a synthesis software by computer aided design (CAD) is constructed, and the interface of the software and the main functions of the compiled programs are explained. Finally, the software operation is carried out, and the effectiveness and complexity of the implemented algorithms are proved. Taking typical ALs 1Q1T3P and 1Q6T as examples, the feature description is generated and the CGs are drawn automatically. The research results of this paper achieve one-to-one correspondence between a CG and its feature description and draws the CGs by given ALs automatically, which avoids the omission and repetition of the CGs during the synthesis process. [ABSTRACT FROM AUTHOR]

Due to the limited memory and computing resources in the real application of target detection, the method is challenging to implement on mobile and embedded devices. In order to achieve the balance between detection accuracy and speed in pedestrian-intensive scenes, an improved lightweight dense pedestrian detection algorithm GS-YOLOv5 (GhostNet GSConv- SIoU) is proposed in this paper. In the Backbone section, GhostNet is used to replace the original CSPDarknet53 network structure, reducing the number of parameters and computation. The CBL module is replaced with GSConv in the Head section, and the CSP module is replaced with VoV-GSCSP. The SloU loss function is used to replace the original IoU loss function to improve the prediction box overlap problem in dense scenes. The model parameters are reduced by 40% and the calculation amount is reduced by 64% without losing the average accuracy, and the detection accuracy is improved by 0.5%. The experimental results show that the GS-YOLOv5 can detect pedestrians more effectively under limited hardware conditions to cope with dense pedestrian scenes, and it is suitable for the online real-time detection of pedestrians. [ABSTRACT FROM AUTHOR]

The key to image depth estimation is to accurately find corresponding points between the left and right images. A binocular camera can directly estimate the depth of the left and right image range, which completely avoids the requirement of target recognition accuracy in a monocular depth estimation. However, it is difficult for binocular stereo matching to accurately segment objects and find matching points in the ill-posed areas (weak texture, deformation, object edge, etc.) of the left and right images. In the semantic segmentation task, atrous convolution is used to solve the contradiction between the receptive field and the segmentation accuracy. This research focused on balancing the impact of holes on the segmentation task. In addition, in order to solve the issue where matching points in the ill-posed regions of left and right images are affected by noise, we used a 3D convolution to aggregate the cost volume to obtain better accuracy. However, the 3D convolution method is prone to mismatching in ill-posed areas of the image. To tackle the problems above, we proposed a dense grouping atrous convolution spatial pyramid pooling (DenseGASPP) method. The feature of the DenseGASPP method is that there is a dense connection between the group atrous convolutions to fully integrate feature information. This method can expand the receptive field and balance the effect of holes on the segmentation task. Moreover, we introduced multi-scale cost aggregation into our method, which uses the repeated exchange of information between cost volumes of different scales to obtain rich contextual information and reduce the mismatching of the network. To evaluate the performance of our method, we conducted several groups of typical algorithm experiments on the scene flow and KITTI 2015 standard datasets. From the results, our model achieves better performance, reducing the EPE from 1.09 to 0.67, which improves the mismatching ability of binocular depth estimation algorithm in ill-posed regions. [ABSTRACT FROM AUTHOR]

In this investigation, purified attapulgite (ATT) and polyvinyl alcohol (PVA) were utilized to fabricate nanocomposite hydrogels and a xerogel, with a focus on studying the impact of minor additions of ATT on the properties of the PVA nanocomposite hydrogels and xerogel. The findings demonstrated that at a concentration of 0.75% ATT, the water content and gel fraction of the PVA nanocomposite hydrogel reached their peak. Conversely, the nanocomposite xerogel with 0.75% ATT reduced its swelling and porosity to the minimum. SEM and EDS analyses revealed that when the ATT concentration was at or below 0.5%, nano-sized ATT could be evenly distributed in the PVA nanocomposite xerogel. However, when the concentration of ATT rose to 0.75% or higher, the ATT began to aggregate, resulting in a decrease in porous structure and the disruption of certain 3D porous continuous structures. The XRD analysis further affirmed that at an ATT concentration of 0.75% or higher, a distinct ATT peak emerged in the PVA nanocomposite xerogel. It was observed that as the content of ATT increased, the concavity and convexity of the xerogel surface, as well as the surface roughness, decreased. The results also confirmed that the ATT was evenly distributed in the PVA, and a combination of hydrogen bonds and ether bonds resulted in a more stable gel structure. The tensile properties exhibited that when compared with pure PVA hydrogel, the maximum tensile strength and elongation at break were achieved at an ATT concentration of 0.5%, indicating increases of 23.0% and 11.8%, respectively. The FTIR analysis results showed that the ATT and PVA could generate an ether bond, further confirming that ATT could enhance the PVA properties. The TGA analysis showed that the thermal degradation temperature peaked when the ATT concentration was at 0.5%, providing further evidence that the compactness of the nanocomposite hydrogel and the dispersion of the nanofiller was superior, contributing to a substantial increase in the mechanical properties of the nanocomposite hydrogel. Finally, the dye adsorption results displayed a significant rise in dye removal efficiency for methylene blue with the increase in the ATT concentration. At an ATT concentration of 1%, the removal efficiency rose by 103% compared with that of the pure PVA xerogel. [ABSTRACT FROM AUTHOR]

Traditional business process-extraction models mainly rely on structured data such as logs, which are difficult to apply to unstructured data such as images and videos, making it impossible to perform process extractions in many data scenarios. Moreover, the generated process model lacks analysis consistency of the process model, resulting in a single understanding of the process model. To solve these two problems, a method of extracting process models from videos and analyzing the consistency of process models is proposed. Video data are widely used to capture the actual performance of business operations and are key sources of business data. Video data preprocessing, action placement and recognition, predetermined models, and conformance verification are all included in a method for extracting a process model from videos and analyzing the consistency between the process model and the predefined model. Finally, the similarity was calculated using graph edit distances and adjacency relationships (GED_NAR). The experimental results showed that the process model mined from the video was better in line with how the business was actually carried out than the process model derived from the noisy process logs. [ABSTRACT FROM AUTHOR]

This study comprehensively characterized and compared the aroma differences between four different grades of Fenjiu (FJ, the most representative light-flavor Baijiu). Aroma-active compounds were analyzed by liquid-liquid extraction (LLE) coupled with gas chromatography-olfactometry-mass spectrometry (GC-O-MS). A total of 88 aroma-active compounds were identified, and 70 of them were quantified. The results showed that a majority of aroma compounds in high-grade FJ had higher aroma intensities and concentrations. Among these compounds, there were 28 compounds with odor activity values (OAVs) greater than one in all four wines, which indicated that they might contribute to the characteristic aroma of FJ. Temporal dominance of sensation (TDS) and quantitative descriptive analysis (QDA) were used to characterize the sensory differences. The results suggested that high-grade FJ had a rich, pleasant and lasting retronasal aroma perception and exhibited pleasant orthonasal aroma of floral, fruity, sweet and grassy. Partial least squares regression (PLSR) analysis effectively distinguished four kinds of FJ and revealed associations between the orthonasal aroma attributes and the aroma compounds with OAVs >1. There were 15 compounds with variable importance in projection (VIP) values >1, and they were considered potential aroma markers for quality prediction. [ABSTRACT FROM AUTHOR]

The size and distribution of ceramic particles in aluminum matrix composites have been reported to remarkably influence their properties. For a single ceramic particle, the particle size is too small and prone to agglomeration, which makes the mechanical properties of the composites worse. When the ceramic particle size is too large, the particles and alloy at the interface are not firmly bonded, and the effect of dispersion distribution is not achieved, which will also reduce the mechanical properties of the composites. The multi-size ceramic particles are expected to improve this situation, while their effect on hot workability is less studied. In this study, the hot deformation behavior, constitutive model, processing map and SEM microstructure were investigated to evaluate the hot workability of multi-size SiC particle-reinforced 6013 aluminum matrix composites. The results showed that the increased deformation temperature and decreased strain rate could decrease flow stresses. The flow stress behaviors of the composites can be described by the sine-hyperbolic Arrhenius equation with the deformation activation energy of Q = 205.863 kJ/mol. The constitutive equation of the composites is ε   ˙ = 3.11592 × 10 13 sinh 0.024909 σ 4.12413 exp − 205863 R T . Then, the hot processing map of the SiCp/6013 composites was constructed and verified by SEM observations. The rheological instability zone was in the region of a high strain rate. The optimal processing zone for composites was 450~500 °C and 0.03~0.25 s−1. In addition, the strain level was found to increase both the Q value and the area of the instability zone. [ABSTRACT FROM AUTHOR]

Leaf nutrient resorption traits are regarded as important indicators reflecting the strategy of plant nutrient conservation, yet the mechanism underlying the variation of resorption traits in different plant growth forms (PGFs) remains unclear. In order to untangle the phylogenetic and environmental influences on leaf nitrogen (N) and phosphorus (P) resorption traits between woody and herbaceous plants, we investigated N and P contents of green and senesced leaves in 53 species along an altitudinal gradient (1374–3649 m) in the Taibai Mountain of central China and estimated leaf N and P resorption efficiency and proficiency. Our results show that leaf N and P resorption efficiency (NRE and PRE) had significant positive trends with altitude in both woody and herbaceous plants (all p < 0.05); however, their altitudinal patterns of N and P resorption proficiency (NRP and PRP) were different. For woody plants, leaf NRP and NRE:PRE first decreased and then increased with altitude (p < 0.05), while NRP:PRP had the opposite trend (p < 0.05). In herbaceous plants, leaf NRP and PRP decreased but NRP:PRP increased with altitude (p < 0.05). Climatic factors exerted the major influences on the variation in leaf NRE and PRE (18.5–24.8% explained variation). However, phylogenetic taxonomy mainly affected the variation of leaf PRP and NRP:PRP (45.2% and 41.4% explained variation) in all species, NRP:PRP in woody plants (37.8% explained variation), and NRE:PRE in herbaceous plants (49.7% explained variation). In addition, leaf NRP:PRP showed a significant phylogenetic signal (Blomberg's p < 0.05). These results highlight the importance of taking PGFs and phylogenetic information into consideration when examining the interspecies variation in leaf resorption under environmental changes, which can advance our knowledge of plant nutrient utilization strategies in response to fluctuating environments and lay the groundwork for the development of complex element biogeochemical models. [ABSTRACT FROM AUTHOR]

In global trade, the manufacture and consumption of cotton textile products are intervening in the hydrological cycle. To address the relationship between the product system and the unsustainable use of local water resources, a spatial water footprint assessment is needed. This study presents a spatial water footprint method that was demonstrated in the case of domestically produced cotton T-shirts in three recycle scenarios. The results showed that the water scarcity footprint of conventional T-shirt, eco T-shirt, recycled T-shirt is 2.45 H2O eq, 1.74 H2O eq, 8 × 10−2 H2O eq, respectively, and the water-eutrophication footprint of conventional T-shirt, eco T-shirt, recycled T-shirt is 1.18 × 10−2 PDF·m2·yr−1, 9.47 × 10−3 PDF·m2·yr−1, 4.04 × 10−3 PDF·m2·yr−1, respectively. Two interesting results have been found. Firstly, the hydrosphere has been affected by manufacture and consumption; thus any choice made by manufacturers and consumers may lead to an impact on the water resource in a region that is far from the location. Secondly, the effect of water footprint reduction will be more apparent in places with severe water stress. The spatial water footprint offers a transparent result of each phase's potential contribution to the local environment and could make a quantitative comparison between product stages, products, and local impacts. Thus, spatial water footprint will be a critical component in the sustainability management improvement of the supply chain. [ABSTRACT FROM AUTHOR]

Molecular farming utilizes plants as a platform for producing recombinant biopharmaceuticals. Duckweed, the smallest and fastest growing aquatic plant, is a promising candidate for molecular farming. However, the efficiency of current transformation methods is generally not high in duckweed. Here, we developed a fast and efficient transformation procedure in Lemna minor ZH0403, requiring 7–8 weeks from screening calluses to transgenic plants with a stable transformation efficiency of 88% at the DNA level and 86% at the protein level. We then used this transformation system to produce chicken interleukin-17B (chIL-17B). The plant-produced chIL-17B activated the NF-κB pathway, JAK-STAT pathway, and their downstream cytokines in DF-1 cells. Furthermore, we administrated chIL-17B transgenic duckweed orally as an immunoadjuvant with mucosal vaccine against infectious bronchitis virus (IBV) in chickens. Both IBV-specific antibody titer and the concentration of secretory immunoglobulin A (sIgA) were significantly higher in the group fed with chIL-17B transgenic plant. This indicates that the duckweed-produced chIL-17B enhanced the humoral and mucosal immune responses. Moreover, chickens fed with chIL-17B transgenic plant demonstrated the lowest viral loads in different tissues among all groups. Our work suggests that cytokines are a promising adjuvant for mucosal vaccination through the oral route. Our work also demonstrates the potential of duckweed in molecular farming. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the prognostic value of interventricular septum thickness (IVSd) on the incidence of cardiovascular diseases. Based on the general population in Northeast China, 10,349 participants were successfully followed up for echocardiography over a median follow-up time of 4.66 years, among which 4801 were hypertensive. Coronary heart disease (CHD) and myocardial infarction (MI) incidence were followed up. Cox proportional hazards models were used to estimate the association of the baseline IVSd with adverse outcomes. IVS hypertrophy increased incident rates of CHD and MI compared with normal IVSd in the overall population and in the female sex-stratification group. In males, IVS hypertrophy had parallel increase rates of CHD (all p < 0.05). Kaplan–Meier analysis showed that IVS hypertrophy could predict CHD and MI incidence and CHD-free and MI-free survival. Multivariable Cox analysis revealed that IVS hypertrophy was correlated with CHD incidence (HR = 1.155, 95% CI = 1.155–2.861, p = 0.01) and MI incidence (HR = 2.410, 95% CI = 1.303–4.458, p = 0.005). In women, IVS hypertrophy was independently associated with CHD and MI incidence (all p < 0.05). Our prospective cohort study illustrated that IVS hypertrophy detected by echocardiography has a prognostic significance for CHD and MI. Therefore, the early detection of IVSd should be conducted to avoid adverse outcomes in further clinical practice. [ABSTRACT FROM AUTHOR]

The transmission of satellite payload data is critical for services provided by aerospace ground networks. To ensure the correctness of data transmission, the TCP data transmission protocol has been used typically. However, the standard TCP congestion control algorithm is incompatible with networks with a long time delay and a large bandwidth, resulting in low throughput and resource waste. This article compares recent studies on TCP-based acceleration algorithms and proposes an acceleration algorithm based on the learning of historical characteristics, such as end-to-end delay and its variation characteristics, the arrival interval of feedback packets (ACK) at the receiving end and its variation characteristics, the degree of data packet reversal and its variation characteristics, delay and jitter caused by the security equipment's deep data inspection, and random packet loss caused by various factors. The proposed algorithm is evaluated and compared with the TCP congestion control algorithms under both laboratory and ground network conditions. Experimental results indicate that the proposed acceleration algorithm is efficient and can significantly increase throughput. Therefore, it has a promising application prospect in high-speed data transmission in aerospace-ground service networks. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 is transmitted by contacting; however, the virus is so active that it can attach to objects and be transmitted from objects to humans via such contacting. The virus, which spreads through some living or inanimate-mediated processes, is more dangerous. On the basis of the routine contact transmission of infectious diseases, this paper further discusses the scope and efficiency of infectious diseases with indirect transmission. Through the study of two different transmission routes, the dynamic models of infectious diseases were constructed. The propagation of these two processes is theoretically studied using a differential equation model and stability analysis theory, and some actual virus propagation processes are simulated by numerical solutions. The prevention and control methods of infectious diseases are given, which lay the theoretical foundation for the discussion of related problems in practical application. [ABSTRACT FROM AUTHOR]

An active wrist can deliver both bending and twisting motions that are essential for soft grippers to perform dexterous manipulations capable of producing a wide range movements. Currently, the versions of gripper wrists are relatively heavy due to the bending and twisting motions performed by the motors. Pneumatic soft actuators can generate multiple motions with lightweight drives. This research evaluates a pneumatic soft wrist based on four parallel soft helical actuators. The kinematics models for predicting bending and twisting motions of this soft wrist are developed. Finite element method simulations are conducted to verify the functions of bending and twisting of this wrist. In addition, the active motions of the soft pneumatic wrist are experimentally demonstrated. Based on sensitivity studies of geometric parameters, a set of parameter values are identified for obtaining maximum bending and twisting angles for a bionic human wrist. Through simulation and experimental tests of the soft wrist for a soft gripper, the desired bending and twisting motions as those of a real human hand wrist are established. [ABSTRACT FROM AUTHOR]

The aircraft anti-skid braking system (AABS) plays an important role in aircraft taking off, taxiing, and safe landing. In addition to the disturbances from the complex runway environment, potential component faults, such as actuators faults, can also reduce the safety and reliability of AABS. To meet the increasing performance requirements of AABS under fault and disturbance conditions, a novel reconfiguration controller based on linear active disturbance rejection control combined with deep reinforcement learning was proposed in this paper. The proposed controller treated component faults, external perturbations, and measurement noise as the total disturbances. The twin delayed deep deterministic policy gradient algorithm (TD3) was introduced to realize the parameter self-adjustments of both the extended state observer and the state error feedback law. The action space, state space, reward function, and network structure for the algorithm training were properly designed, so that the total disturbances could be estimated and compensated for more accurately. The simulation results validated the environmental adaptability and robustness of the proposed reconfiguration controller. [ABSTRACT FROM AUTHOR]

Castanopsis sclerophylla (Lindl.) Schott. is a canopy tree species of evergreen broad-leaved forests in subtropical China. In this study, the genetic diversity and population structure of C. sclerophylla were investigated by using chloroplast DNA sequences and nuclear microsatellite markers. Permutation tests with chloroplast DNA sequences indicated the presence of phylogeographic structure in C. sclerophylla. Based on nuclear microsatellite markers, Bayesian clustering analysis revealed eastern-to-western differentiation in C. sclerophylla, and the analysis of molecular variance suggested population divergence has arisen along the Xuefeng, Luoxiao, and Wuyi mountain ranges. The approximate Bayesian computation demonstrated that the genetic diversity pattern of C. sclerophylla could be explained by geographic isolation followed by secondary contact. Ecological niche modelling showed that distribution of C. sclerophylla shrank southward at the Last Glacial Maximum and expanded northward at the Mid Holocene. These results suggested that the uplift of the Xuefeng, Luoxiao, and Wuyi mountain ranges and the interglacial–glacial climate change shaped the genetic diversity of C. sclerophylla. The Luoxiao mountain range should be considered as a key conservation unit of C. sclerophylla due to its higher level of genetic diversity. Our study supplies important information for prioritizing the conservation and sustainable utilization of C. sclerophylla, and provides insight on the dynamics of evergreen broad-leaved forests in subtropical China. [ABSTRACT FROM AUTHOR]

Li2O2, as the cathodic discharge product of aprotic Li-O2 batteries, is difficult to electrochemically decompose. Transition-metal oxides (TMOs) have been proven to play a critical role in promoting the formation and decomposition of Li2O2. Herein, a NiO/CNT catalyst was prepared by anchoring a NiO nanosheet on the surface of CNT. When using the NiO/CNT as a cathode catalyst, the Li-O2 battery had a lower overpotential of 1.2 V and could operate 81 cycles with a limited specific capacity of 1000 mA h g−1 at a current density of 100 mA g−1. In comparison, with CNT as a cathodic catalyst, the battery could achieve an overpotential of 1.64 V and a cycling stability of 66 cycles. The introduction of NiO effectively accelerated the generation and decomposition rate of Li2O2, further improving the battery performance. SEM and XRD characterizations confirmed that a Li2O2 film formed during the discharge process and could be fully electrochemical decomposed in the charge process. The internal network and nanoporous structure of the NiO/CNT catalyst could provide more oxygen diffusion channels and accelerate the decomposition rate of Li2O2. These merits led to the Li-O2 battery's better performance. [ABSTRACT FROM AUTHOR]

Land-use change has a significant impact on the structure and function of ecosystems and is an important reason for the imbalance between the supply and demand of ecosystem services. Pollination services are indispensable functions of ecosystems. In recent years, land-use change has caused a decline in the abundance of pollinators, thereby affecting the supply of pollination services, which has been a major concern for governments and scholars. Currently, there is an insufficient exploration of the impact mechanism of land-use change on pollination services. The application of a pollination service evaluation model based on land-use data uses a large amount of empirical data, which greatly affects the accuracy of regional evaluation results. This study uses Huizhou as a representative example. Remote sensing images from 2015 and 2019 were used to interpret the land-use data of the region, and the spatiotemporal changes in the land use were then analyzed. Due to their high pollination dependence, litchi and longan were selected as the research objects. Basic data such as the main pollinator species of litchi and longan and floral plant species were obtained through field sampling surveys. The InVEST model was used to evaluate the abundance of pollinators in litchi and longan orchards, and the abundance of pollinators was used to represent the value of pollination services in litchi and longan orchards. Then, the Hotspot analysis method was used to analyze the change in the spatial pattern of the pollinator abundance in litchi and longan orchards. The main influencing factors of pollination service in litchi and longan orchards were analyzed by a Geographical detector. Finally, we have explored the impact mechanism of land-use change on pollination services. The following are the results of this research. The pollinator abundance in the orchards of litchi and longan and their buffer zones in Huizhou decreased by 6.64% and 13.94% from 2015 to 2019, respectively. The wild bee abundance in forest land and rainfed cropland decreased by varying degrees. The spatial aggregation characteristics of pollinator abundance in litchi and longan orchards demonstrated an increase in cold spots, whereas the hot spots decreased and were more dispersed. In the study area, the area change and land-use change of natural or semi-natural habitats, such as forest land, rainfed cropland, and grassland, affected the pollination services for litchi and longan orchards. Within the types of changing land-use, the change of forest land has the greatest impact on litchi and longan pollination services. The impact degrees of Forest land area, rainfed cropland area, area under litchi and longan orchards, and forest landscape fragmentation on the pollination services for litchi and longan orchards were 0.20, 0.16, 0.21, and 0.26, respectively. [ABSTRACT FROM AUTHOR]

The design of a supersonic-supersonic mixing layer facility was motivated by the need for a benchmark experimental platform to study the physical phenomena underlying supersonic mixing layers. The facility is an intermittent blowdown wind tunnel characterized by a two-stream design separated by a splitter plate in the middle of the nozzle. The splitter plate ends exactly at the start of the mixing layer test section. The Mach number of the primary stream is M1 = 3 for all nozzles and the secondary streams are M2 = 2, 2.5, and 2.9 to generate different convective Mach numbers of Mc = 0.25, 0.10, and 0.01, respectively. The facility was calibrated by pressure measurements to verify the Mach number and the pressure distribution in the streamwise direction. Large-eddy simulation (LES) was performed to illustrate a full view of the turbulent compressible mixing layer flow field and to compare this against the experimental data. Optical diagnosis measurements, i.e., femtosecond laser-induced electronic excitation tagging velocimetry (FLEET) for velocity measurement and focused laser differential interferometer (FLDI) for the density fluctuation, were also performed on the facility. [ABSTRACT FROM AUTHOR]

The time-delay estimation (TDE) method is the primary method for predicting leakage locations in buried water distribution pipelines. The accuracy of TDE depends on the acoustic speed and attenuation of the leakage signal propagating along the pipeline. The analytical prediction model is the typical approach for obtaining the propagation speed and attenuation of leakage waves. However, the embedding parameters of the buried pipe in this model must be measured using soil tests, which are very difficult, costly, and time-consuming. These factors restrict the application of the TDE method in pinpointing pipeline leakage. A method for inverse identification of pipe embedding parameters using discrete wavenumbers obtained in field testing is presented in this paper, and the differential evolution algorithm is introduced as an optimization solution. A field experiment is conducted to validate the method, and the test wavenumbers are measured in a cast-iron pipeline. The estimated sensitive parameters in the analytical model using the method are soil elastic modulus, Poisson's ratio, and pipe–soil contact coefficient, while the conventional soil test is used to measure the soil density due to the character of the optimization algorithm and the soil properties. The application effects show that the estimated parameters are close to those measured from a conventional soil test. The wave speed based on the estimated parameters was an excellent match for the on-site test in the engineering application. This work provides a less costly and more straightforward way to apply the TDE method for leak localization in buried pipelines. [ABSTRACT FROM AUTHOR]

The recent advances in wearable sensors and intelligent human–machine interfaces have sparked a great many interests in conductive fibers owing to their high conductivity, light weight, good flexibility, and durability. As one of the most impressive materials for wearable sensors, conductive fibers can be made from a variety of raw sources via diverse preparation strategies. Herein, to offer a comprehensive understanding of conductive fibers, we present an overview of the recent progress in the materials, the preparation strategies, and the wearable sensor applications related. Firstly, the three types of conductive fibers, including metal-based, carbon-based, and polymer-based, are summarized in terms of their principal material composition. Then, various preparation strategies of conductive fibers are established. Next, the primary wearable sensors made of conductive fibers are illustrated in detail. Finally, a robust outlook on conductive fibers and their wearable sensor applications are addressed. [ABSTRACT FROM AUTHOR]

The combustion characteristics of a hydrogen-fueled supersonic combustor featuring a large cavity length-to-depth ratio (i.e., 11) were examined by performing experimental trials while varying the fuel injector positions and equivalence ratios. During these trials, flame chemiluminescence images were acquired simultaneously from the side and bottom of the combustor under Mach 2.0 inflow conditions. The flame was observed to stabilize inside the cavity under all conditions. Proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) analyses of sequential flame chemiluminescence images demonstrated the important effects of oblique shocks induced by fuel injection and heat release on flame stabilization. Because fluctuations in the locations of the flame and of the intense heat release zone were not observed and no dominant frequency was identified in POD and DMD analyses, the present configuration was evidently able to suppress combustion instability. The present research provides preliminary guidance for exploring the feasibility of using cavity combustors with large length-to-depth ratios in scramjet engines. [ABSTRACT FROM AUTHOR]

Featured Application: This study proposes a method for evaluating the siltation of permeable pavement, and it is concluded that the road noise is proportional to the degree of siltation of permeable pavement. This study mainly uses PFC (particle follow code) to simulate the void characteristics of permeable asphalt mixture, and uses these to simulate the silting process. Then, a tire drop test was used to evaluate the noise reduction performance of permeable asphalt concrete. Finally, a self-made ring rutting test machine was used to simulate the silting process. Through experiments, the following conclusions were obtained: 1. The critical size of the sludge particle size is 0.3 mm–0.6 mm. 2. The quality of the water-permeable asphalt concrete specimens increased by 13% before and after silting, and the porosity of the specimens finally decreased from about 20% to about 8%. The water-permeable function only retained less than 20% of the original, and the water-permeable function was basically lost. 3. By measuring the road noise detection, it was found that the road noise is directly proportional to the degree of blockage of the permeable road. Compared with the original road with a perfect permeable function, the road noise of the completely blocked road increased by about 4 decibels. This study reveals the silting process of permeable asphalt mixture and the key particle size of the silt, which is of great significance for the detection, cleaning and maintenance of permeable asphalt pavements. [ABSTRACT FROM AUTHOR]

An improved strain-transfer model was developed for surface-bonded sapphire-derived fiber Bragg grating sensors. In the model, the core and cladding of the fiber are separated into individual layers, unlike in conventional treatment that regards the fiber as a unitive structure. The separation is because large shear deformation occurs in the cladding when the core of the sapphire-derived fiber is heavily doped with alumina, a material with a high Young's modulus. Thus, the model was established to have four layers, namely, a core, a cladding, an adhesive, and a host material. A three-layer model could also be obtained from the regressed four-layer model when the core's radius increased to that of the cladding, which treated the fiber as if it were still homogeneous material. The accuracy of both the four- and three-layer models was verified using a finite-element model and a tensile-strain experiment. Experiment results indicated that a larger core diameter and a higher alumina content resulted in a lower average strain-transfer rate. Error percentages were less than 1.8% when the four- and three-layer models were used to predict the transfer rates of sensors with high and low alumina content, respectively. [ABSTRACT FROM AUTHOR]

Acoustic metamaterial science is an emerging field at the frontier of modern acoustics. It provides a prominent platform for acoustic wave control in subwavelength-sized metadevices or metasystems. However, most of the metamaterials can only work in a narrow frequency band once fabricated, which limits the practical application of acoustic metamaterials. This paper highlights some recent progress in tunable acoustic metamaterials based on various modulation techniques. Acoustic metamaterials have been designed to control the attenuation of acoustic waves, invisibility cloaking, and acoustic wavefront engineering, such as focusing via manipulating the acoustic impedance of metamaterials. The reviewed techniques are promising in extending the novel acoustics response into wider frequency bands, in that tunable acoustic metamaterials may be exploited for unusual applications compared to conventional acoustic devices. [ABSTRACT FROM AUTHOR]

A primary focus of rice breeding and production is the optimization of yield and quality. Currently, semi-waxy japonica rice is widely planted in the middle and lower reaches of the Yangtze River due to its good eating quality and strong reputation among consumers. However, little information is yet available on grain yield formation and rice quality characteristics of these semi-waxy japonica rice varieties with different grain yields. In this study, three high-yielding (HGY) semi-waxy japonica rice varieties and three low-yielding (LGY) semi waxy japonica rice varieties were compared for population quality and rice quality in 2018 and 2019. The average values of spikelet per panicle, 1000-grain weight, and total spikelet number of the HGY varieties were significantly higher than those of the LGY varieties, while the panicle number and filled grain rate showed the opposite. Compared with the LGY varieties, the HGY varieties had a larger leaf area index at each growth stage, with a larger high efficient leaf area composed of a larger leaf length and width and smaller leaf angles of the top three leaves, as well as a greater single stem-sheath weight, more total dry matter accumulation, and longer growth duration from elongating to maturity. There were significant differences in rice quality between the HGY and LGY varieties. Compared with the LGY varieties, the head milled rice rate of the HGY varieties decreased significantly, and the chalky kernel rate and chalkiness degree increased significantly. Due to the low protein content, high peak viscosity, trough viscosity, and final viscosity and breakdown, as well as low setback, consistence, and pasting temperature of the HGY varieties, their taste values were significantly better than those of the LGY varieties. These results suggest that the HGY varieties could achieve a synergistic improvement of grain yield and eating quality, but the milling quality and appearance quality require further improvement. [ABSTRACT FROM AUTHOR]

Particle image velocimetry (PIV) is a non-contact, instantaneous and full-flow velocity measurement method based on cross-correlation analysis of particle image. It is widely used in fluid mechanics and aerodynamics. Laser sheet optical system is one of the key equipment of PIV, and it is an important guarantee to obtain high definition particle image. In the PIV measurement task of large low speed wind tunnel, in order to solve the problem of sheet light illumination uniformity of large size model and take into account the requirements of PIV technology on the thickness of the sheet light, a hybrid algorithm is used to design a high uniformity laser sheet optical system based on the theory of physical optics. The simulation results show that the size of the sheet light is 400 mm × 1 mm, the diffraction efficiency reaches 97.77%, and the non-uniformity is only 0.03%. It is helpful to acquire high-resolution images of particles in the full field of view. It also can be applied to a series of non-contact flow field measurement techniques such as plane laser induced fluorescence, filtered Rayleigh scattering and two-color plane laser induced fluorescence temperature measurement. [ABSTRACT FROM AUTHOR]

The detection of trace aroma compounds in samples with complex matrices such as Chinese liquor (Baijiu) requires a combination of several methods, which makes the analysis process very complicated. Therefore, a headspace solid-phase microextraction (HS-SPME) method coupled with two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) was developed for the quantitation of a large number of trace compounds in Baijiu. Optimization of extraction conditions via a series of experiments revealed that dilution of the alcohol content of 8 mL of Baijiu to 5%, followed by the addition of 3.0 g of NaCl and subsequent SPME extraction with DVB/CAR/PDMS fiber coating over 45 min at 45 °C was the most suitable. To check the matrix effects, various model Baijiu matrices were investigated in detail. The quantitative method was established through an optimized model synthetic solution, which can identify 119 aroma compounds (esters, alcohols, fatty acids, aldehydes and ketones, furans, pyrazines, sulfur compounds, phenols, terpenes, and lactones) in the Baijiu sample. The developed procedure provided high recovery (86.79–117.94%), good repeatability (relative standard deviation < 9.93%), high linearity (R2 > 0.99), and lower detection limits than reported methods. The method was successfully applied to study the composition of volatile compounds in different types of Baijiu. This research indicated that the optimized HS-SPME–GC×GC-TOFMS method was a valid and accurate procedure for the simultaneous determination of different types of trace compounds in Baijiu. This developed method will allow an improved analysis of other samples with complex matrices. [ABSTRACT FROM AUTHOR]

This paper proposes the combination of headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and chemometrics as a method to detect the age of Chinese liquor (Baijiu). Headspace conditions were optimized through single-factor optimization experiments. The optimal sample preparation involved diluting Baijiu with saturated brine to 15% alcohol by volume. The sample was equilibrated at 70 °C for 30 min, and then analyzed with 200 μL of headspace gas. A total of 39 Baijiu samples from different vintages (1998–2019) were collected directly from pottery jars and analyzed using HS-GC-IMS. Partial least squares regression (PLSR) analysis was used to establish two discriminant models based on the 212 signal peaks and the 93 identified compounds. Although both models were valid, the model based on the 93 identified compounds discriminated the ages of the samples more accurately according to the goodness of fit value (R2) and the root mean square error of prediction (RMSEP), which were 0.9986 and 0.244, respectively. Nineteen compounds with variable importance for prediction (VIP) scores > 1, including 11 esters, 4 alcohols, and 4 aldehydes, played vital roles in the model established by the 93 identified compounds. Overall, we determined that HS-GC-IMS combined with PLSR could serve as a rapid and accurate method for detecting the age of Baijiu. [ABSTRACT FROM AUTHOR]

Sweetness is an important Baijiu quality marker, but there is limited research on it. In this study, the main contributors to Baijiu sweetness were identified by "sensomics" combined with "flavoromics". A total of 43 volatile compounds (mostly esters) were found that appeared to contribute to Baijiu sweetness, through sensory-guided fractionation and compositional analysis. Correlation analysis between the volatile composition and perceived sweetness of 18 Baijiu samples with different sweet intensities identified 14 potential contributors. Additional testing verified that combining the 14 compounds reproduced Baijiu sweetness exactly, and omission testing identified ethyl hexanoate, hexyl hexanoate and ethyl 3-methylbutanoate as the major contributors to Baijiu sweetness. These findings not only broadened our understanding of Baijiu sweetness, but also highlighted the major contribution of volatile compounds to sweetness perception, knowledge which may facilitate future flavor modification of a wide variety of foods and beverages. [ABSTRACT FROM AUTHOR]

As a class of redox active materials with some preferable properties, including rigid structure, insoluble characters, and large amounts of nitrogen atoms, covalent triazine frameworks (CTFs) have been frequently adopted as electrode materials in Lithium-ion batteries (LIBs). Herein, a triazine-based covalent organic framework employing 3,4-ethylenedioxythiophene (EDOT) as the bridging unit is synthesized by the presence of carbon powder through Stille coupling reaction. The carbon powder was added in an in-situ manner to overcome the low intrinsic conductivity of the polymer, which led to the formation of the polymer@C composite (PTT-O@C, PTT-O is a type of CTFs). The composite material is then employed in LIBs as anode material. The designed polymer shows a narrow band gap of 1.84 eV, proving the effectiveness of the nitrogen-enriched triazine unit in reducing the band gap of the resultant polymers. The CV results showed that the redox potential of the composite (vs. Li/Li+) is around 1.0 V, which makes it suitable to be used as the anode material in lithium-ion batteries. The composite material could exhibit the stable specific capacity of 645 mAh/g at 100 mA/g and 435 mAh/g at 500 mA/g, respectively, much higher than the pure carbon materials, indicating the good reversibility of the material. This work provides some additional information on electrochemical performance of the triazine and EDOT based CTFs, which is helpful for developing a deep understanding of the structure–performance correlations of the CTFs as anode materials. [ABSTRACT FROM AUTHOR]

Predominant odorants in modern and traditional types of Chinese xiaoqu liquor (Baijiu) were identified and compared by the combined use of gas chromatography−olfactometry, odor activity values (OAVs), and multivariate analyses. A total of 79 aroma compounds were identified in a typical modern type xiaoqu Baijiu (M) and a typical traditional type xiaoqu Baijiu (T), 42 of them had OAV > 1 in both M and T samples. The main differences between the two samples were obtained for the concentration of 23 aroma-active compounds. A total of 22 samples made by different brewing processes were analyzed to confirm the differences. Partial least squares discriminant analysis confirmed that 20 compounds could be used as potential markers for discrimination between modern type xiaoqu Baijiu and traditional type xiaoqu Baijiu. Their difference in content is between 1.5 and 17.9 times for modern type xiaoqu Baijiu and traditional type xiaoqu Baijiu. The results showed the aroma characteristics of modern and traditional type xiaoqu Baijiu clearly and comprehensively, which will provide guidance for modern Baijiu quality control and evaluation. [ABSTRACT FROM AUTHOR]