最新刊期
卷 63 ， 期 1 ， 2024
- 摘要：Quantum speedups for the graph property testing problem is studied： For a given graph and an integer
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发布时间：2024-01-25
Invited article
- 摘要：Airborne LiDAR （light detection and ranging） data are effective for geological hazard risk assessment in vegetation-covered areas because vegetation information can be removed and thus provide true surface morphology. Huoshanzhang in Shanwei， Guangdong Province is a steep and densely vegetated area that is prone to landslides， collapses， and mudslides. This study adopted high-resolution LiDAR data to generate high-precision DEM data and extract terrain factors such as slope， aspect， curvature， undulation， roughness， and mountain shadows， combined with remote sensing images of GF-1 satellite， identified a total of 44 landslides/collapses. Among them， three low-probability landslides/collapses were removed based on the variable dimensional and fractal model， the determined weight of each terrain factor， and the confirmed probability of each interpreted landslide/collapse. The area was divided into 6 sub-regions according to the characteristics of the valleys and the geological hazard risk assessment of each sub-region was conducted based on the terrain characteristics， landslide/collapse density and volume， and human activities. The results indicate that high-precision terrain factors generated from LiDAR data of vegetation impacts eliminated are an effective source for geological hazard interpretation in vegetation-covered areas.关键词：geological disaster;LiDAR;risk assessment;Huoshanzhang
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发布时间：2024-01-25 - 摘要：Based on meteorological observation data and high-resolution numerical simulation results, the evolution and mechanism of convective organization and modes in a squall line over South China on May 11, 2020, were analyzed in four stages: nascent stage, enhanced stage, mature stage, and decay stage. The results show that the squall line occurred in the strong divergence zone of the upper jet stream. With the deepening and eastward moving of the south branch of the trough, the warm and wet advection in the low layer and mesoscale convergence line on the ground provided favorable conditions of water vapor, heat, and uplift triggering. In the nascent stage, the squall developed in a manner of Broken Lines with medium to strong convective available potential energy and maximum convective inhibition, in the environment of the maximum thermal condition. In the mature stage, a trailing stratiform squall was formed, and the low-level wind shear and cold pool intensity gradually reached a balanced state. During the decay stage, the phase mode of the squall line changed, mainly affected by the thermal condition caused Back Building mode convective cells, and also by different water vapor and wind shear conditions in the lower layer. In South China, it requires high convective effective potential energy to generate a squall line of stratiform cloud mode with trailing tail strong thermal conditions to maintain the squall line. The convective available potential energy, convective inhibition, Bulk Richardson number, and storm-relative helicity can indicate the type and structure mode of convective monomer formation.关键词：South China squall line;numerical simulation;organizational mode;Back-Building mode
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发布时间：2024-01-25 - 摘要：Land use classification is critical to the management of land space. To improve the accuracy of land use classification, this study takes Bohu County as the research area, uses Sentinel-2A images to extract spectral features, and combines radar, spectral index, soil, and terrain features to construct six object-oriented land use classification models. We then use a simple non-iterative clustering algorithm and random forest algorithm to segment and classify the images and obtain the classification accuracy and feature importance ranking of the model. In the final step, we use the classification regression tree algorithm to verify the influence of the auxiliary dataset on the improvement of the classification accuracy. The results show that when using the SNIC algorithm to segment the images, with seed size 17 and compactness 0, the image segmentation effect in this study area is the best. The classification accuracy is the lowest when only spectral information is used, and adding any auxiliary dataset of radar, spectral index, soil, and terrain features can improve the classification accuracy of land use. Among those auxiliary datasets, the effect of terrain features on improving classification accuracy is more significant, and the classification accuracy reaches the highest when all auxiliary datasets are added, with OA=92.34% and Kappa coefficient=0.91. The classification validity is verified using the categorical regression tree algorithm, it shows that the classification effect based on the random forest algorithm is better than that of the categorical regression tree algorithm. The SNIC segmentation algorithm based on the remote sensing cloud platform is integrated into an auxiliary data set for object-oriented classification, which provide a reference for improving the accuracy of land use classification.关键词：land use classification;auxiliary datasets;SNIC segmentation;object-oriented;random forest;sentinel-2A image
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发布时间：2024-01-25 - 摘要：Based on the seventh national census data, this study utilizes descriptive statistical analysis and the Tobit regression model to depict the spatial pattern of townships and identify the factors regarding human settlement that affect the health of the elderly population in Zhaoqing, Guangdong Province. The results are as follows: 1) The health level of the urban elderly population was better than that of rural areas in Zhaoqing. Moreover, the gap between urban and rural areas becomes more pronounced with age and the health advantage for women over men after the age of 70 has been reversed. 2) The spatial characteristics of a healthy environment reveal the uneven distribution of environmental resources. There were noticeable spatial and urban-rural differences in the health level of the elderly population, generally showing a pattern of high in urban areas and low in urban areas. 3) Air quality (PM2.5) has a significant negative correlation with the proportion of healthy elderly. Normalized Difference Vegetation Index (NDVI) plays a positive role in regulating PM2.5 in rural areas, while the number of polluting enterprises and poverty deprivation aggravate the negative impact of PM2.5 on rural health elderly. High-quality housing conditions have a significant positive impact on the health status of the elderly; economic status without primary income and social deprivation negatively predicted the proportion of healthy elderly; the proportion of the senior elderly (>80 years) has a negative impact on the proportion of healthy elderly. Medical security has a positive impact on the health of the disabled elderly in rural areas. This study provides the theoretical basis and decision-making reference for Zhaoqing City to promote the construction of a livable environment for the elderly.关键词：elderly population;health level;human settlement;census;the Tobit regression model
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发布时间：2024-01-25 - 摘要：The study was to explore the mechanism of action of Xiasangju in the treatment of xerophthalmia by using network pharmacology， molecular docking method and cell experiments. The chemical components of Xiasangju were analyzed by ultra-fast high performance liquid chromatography tandem triple quadrupole time-of-flight mass spectrometry （UFLC-Triple-TOF-MS/MS）. Targets of active components were predicted and disease related targets were retrieved with the help of network pharmacologic database and analysis platform. The network was built using cytoscape software and STRING platform. GO and KEGG pathway enrichment analysis was performed using the DAVID database， and the top 4 key targets were matched with their corresponding active component molecules. A hypertonic model of dry eye was constructed in vitro to verify the core target. A total of 61 chemical components were identified， and 24 effective components potentially related to xerophthalmia were selected for further screening. These 24 components were found to interact with 315 potential target proteins. Among them， the key active components of Xiasangju were identified as rosmarinic acid， linarin and chlorogenic acid， which targeted TNF-α， Caspase1， IL-6， and IL-1β. Enrichment analysis revealed that the therapeutic targets of Xiasangju for xerophthalmia were concentrated in multiple biological processes， including the AGE-RAGE signaling pathway， TNF signaling pathway， and others. In cell experiments， these three active components not only significantly inhibited cell viability reduction but also enhanced the migration ability of high osmolarity-induced corneal epithelial cells. They effectively suppressed the expression of Caspase1 and IL-1β genes， as well as the secretion level of TNF-α protein in high osmolarity-induced human corneal epithelial cells. The main active components， rosmarinic acid， linarin and chlorogenic acid， in Xiasangju exerted protective and reparative effects on human corneal epithelial cells under high osmolarity conditions. They reduced the protein level of TNF-α and the relative expression of Caspase1 and IL-1β mRNA.关键词：Xiasangju;xerophthalmia;network pharmacology;molecular docking;experimental validation
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发布时间：2024-01-25 - 摘要：Sogatella furcifera is an important pest of rice. Long-winged adults can migrate over long distances and spread their harm. In this study， the ultramicroscopic characteristics of female adult planthopper with long wings were studied by scanning electron microscopy. The results showed that： The middle of the fore and hind wing surface is thin and the edge is thick. The edge of the middle to the end of the wing has folded. There are many small spines evenly distributed on the back wing surface of the forewing， the length is（3.07± 0.48） μm， and there are many small spines on both sides of the hind wing. There were trichoid sensilla like apparatus on the dorsal surface and ventral surface of the forewing， which could be divided into TS-I and TS-Ⅱ. TS-I distributed in the ventral wing base and perpendicular to the ventral wing vein， and had no obvious basal fossa. The number of TS-I was 4±1.41， and the length was （31.80±2.43） μm. TS-Ⅱ was distributed on the dorsal vein of the wing， and the number of TS-Ⅱ was 5±1.41， the length was （57.25±21.84） μm， and the TS-Ⅱ was located in the basal fossae with obvious depression. Campaniform sensilla like apparatuses were also distributed in the ventral edge of the forewing and in the veins， and the number was 5.00±3.46. In addition， a basiconic sensilla like apparatus with 21.00±4.36 in number and （8.25±2.09） μm in length was found on the ventral edge of the forewing. The results of this study are helpful to further understand the morphological structure of the white back planthopper wing at the ultrastructural level， and understand its ability to migrate and spread， and lay a foundation for better prevention and control measures.关键词：Sogatella furcifera;long-winged;trichoid sensilla like apparatus;campaniform sensilla like apparatus;basiconic sensilla like apparatus
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发布时间：2024-01-25 - 摘要：The metabolites of an endophytic fungus Fusarium lateritium ZMT01 from Oxya chinensis Thunbergwere investigated. The fungus was cultured in rice medium， the monomeric compounds were isolated and purified by the chromatographic technique， and the structures of compounds were identified by analysis of spectroscopy. Ten compounds were isolated and identified as fusopoltide A （1）， fusopoltide B （2）， fusopoltide D （3）， solaniol （4）， javanicin （5）， （1S， 4S， 10S）-3， 4-dihydro-6，9-dihydroxy-8-methoxy-10-（2-oxopropyl）-1，4-methano-2-benzoxepin-5 （1H）-one （6）， 2，2′‐methylenebis（4‐methyl‐6‐tert‐butylphenol） （7）， 2-hydroxymethyl-5-isopropoxy-4-methoxynaphthalen （8）， β-sitosterol （9） and walterolactone A （10）. Among them， compounds 8 and 10 were firstly obtained from the genus Fusarium， and all of them except compound 9 were isolated from Fusarium lateritium for the first time. The antibacterial activities of these compounds were tested in vitro using the two-fold dilution method. Compounds 4 and 5 showed a high inhibitory activity against Escherichia coli with serotype O6 with MIC of 6.25 µg/mL， and compound 4 showed a moderate inhibitory activity against Fusarium oxysporum with MIC of 200 µg/mL.关键词：endophytic fungi;Fusarium lateritium;metabolites;antibacterial activity
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发布时间：2024-01-25 - 摘要：Utilizing a large sample， this study aimed to explore the distribution characteristics and influencing factors of immunoglobulin （Ig） IgG， IgA and IgM during long-term high-intensity training for elite athletes in Guangdong Province， and to establish the corresponding percentile reference values and ranges. A total of 2 274 elite athletes from 35 sports events were recruited from 2012 to 2019. The t-test of one sample was utilized to compare Ig levels between athletes and the general healthy population， while the t-test of two independent samples compared Ig levels across different gender and types of sports. Additionally， one-way ANOVA was used to compare Ig levels across different sports event-groups， seasons， and preparation years for National Games. The generalized estimating equation was applied to analyze the factors affecting athletes' Ig levels. The skewness-median-coefficient of variation method established the percentile reference values and ranges for Ig levels. The results indicated that the levels of IgG （P<0.01）， IgA （P<0.001）， and IgM （P<0.001） in athletes were （11.50±2.20）， （1.92±0.66）， and （1.30±0.58） g/L respectively， significantly lower than those in the general healthy population. The levels of IgG and IgM in male athletes were significantly lower than those in females （P<0.001）. Athletes dominant in physical sports exhibited significantly lower IgG levels compared to those dominant in skill-based sports （P<0.01）. Distinct variances were observed in IgG （P<0.001） and IgM （P<0.01） levels among different sports event-groups， and in IgG levels across various seasons （P<0.05）. The results also indicated that gender （P<0.001）， sports event-groups （P<0.05）， and seasons （P<0.01） were key factors influencing IgG levels， with both gender （P<0.001） and sports event-groups being key influencing factors of IgM levels. Furthermore， the 95% reference range for athletes' IgG， IgA， and IgM were 7.34-16.56， 0.82-3.47， and 0.46-2.91 g/L respectively； for males， they were 7.34-15.71， 0.88-3.47， and 0.46-2.27 g/L， and for females， 7.96-16.56， 0.82-3.36， and 0.63-2.91 g/L. The research suggests that more attention should be paid to the individual evaluations of different gender and sports events， and the impacts of climatic conditions and temperature when monitoring of immune function status of athletes. The percentile reference values and ranges of IgG， IgA， and IgM levels obtained in this study can be accounted in accurately assessing the immune function status of athletes， providing scientific evidence for monitoring training， evaluating the immune system， and regulating nutrition in athletes.关键词：immunoglobulin （Ig）;athlete;training monitoring;reference values;influencing factors
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发布时间：2024-01-25 - 摘要：The interaction between odor molecules and olfactory receptors is a crucial step in olfactory perception and holds significant importance in unraveling the mechanism of olfactory perception. However， obtaining experimental results on the activation relationship between odor molecules and human olfactory receptors is time-consuming and labor-intensive， and the available data on activation relationships is currently insufficient to support intelligent olfactory perception research. Therefore， this study constructed a network of olfactory receptor protein relationships and extracted features to train a model for predicting the activation relationship between odor molecules and olfactory receptors. By integrating the features of odor molecules and the simulated activation relationship of olfactory receptor proteins in olfactory perception prediction， high-precision regression prediction of human olfactory perception was achieved. Experimental results showed that the correlation coefficient of human olfactory perception prediction fused with odor molecule-olfactory receptor activation relationship reached 0.94， significantly outperforming existing olfactory perception prediction models. Additionally， the study summarized the odor molecule-olfactory receptor activation-olfactory perception pattern， enriching our understanding of the mechanism of smell perception. This study introduced observable features of olfactory receptor activation mechanisms into olfactory perception prediction， providing new insights for further exploration and understanding of the mechanism of olfactory perception.关键词：molecular feature extraction;protein feature extraction;olfactory receptor activation prediction;olfactory perception prediction;graph convolution;machine learning
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发布时间：2024-01-25 - 摘要：To realize the red tide identification of Pearl River Estuary with high resolution remote sensing， and to scientifically support red tide disaster prevention and mitigation work. This paper used the high spatial resolution data of the coastal zone imager carried by Haiyang-1C/D satellite， together with the analysis of the spectral characteristics of remote sensing images of turbid water， clean water and red tide in the Pearl River Estuary， to identify red tide by calculating the water hue angle and combining with visual interpretation. This method was used to successfully identify the Cochlodinium geminatum red tide in the Pearl River Estuary from October 26 to November 6， 2020. The hue angle can be used to identify the red tide in the Pearl River Estuary. The hue angle of red tide water varies from 58° to 61°， which has a good identification effect on small area red tide during their initiation， low density red tide and red tide in strip distributed areas.关键词：Pearl River Estuary;red tide;HY-1C/D;hue angle
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发布时间：2024-01-25 - 摘要：China is vigorously developing related technologies of ultra-high voltage power grids at the present stage. However， due to the neglect of the analysis of conductors' mechanical performance， insulation accidents are easily caused in engineering. According to the different relative positions of the suspension points at both ends of the conductor， it can be divided into equal height difference and unequal height difference connection. Therefore， this paper presents an empirical formula for calculating the mechanical properties of short conductor terminals with unequal height difference in different degree of freedom. The stress state of short conductor under the condition of unequal height difference is analyzed. By changing the distance， height difference and angle of wire clamp between suspension points，the force characteristics of terminals in different directions are summarized， and an empirical formula for design reference is derived. The results show that the empirical formula has good engineering applicability. The force at the terminal of the conductor is not only related to the external load，but also related to the distance， height difference，type of the conductor and the angle of the wire clamp used at the terminal.关键词：stiffness effect;conductor model;unequal height difference;short conductor;power system
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发布时间：2024-01-25 - 摘要：The dynamics model of a swimming crocodile is established based on its kinematic model and Lighthill’s slender-body theory. Furthermore， the propulsion efficiency of a swimming crocodiles is calculated using Froude’s theory. The results show that the cruising velocity of the crocodile increases with the increase of the tail’s swinging frequency， amplitude and wavelength.And，the increase of swinging frequency being the greatest contribution， the increase of swavelength being the least contribution. It is also observed that the thrust power increases gradually with the increase of the tail’s swinging frequency， amplitude and wavelength. When the oscillating frequency is 0.7 Hz， the oscillating amplitude is 0.2 m and the wavelength is 1.2 m， the thrust efficiency is up to 64%. The thrust efficiency increases first and then decreases with the increase of Re， and reaches the maximum value when the Re is 3×105， gradually approaching the constantvalue of 55% with the increase of St. The results provid an valuable reference for the development of a crocodile-like robot.关键词：bionic crocodile;wagging thrust;dynamics modeling;swimming efficiency
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发布时间：2024-01-25 - 摘要：A sensitivity analysis approach is proposed for the identification of bolted joint models using Bouc-Wen model， in order to discover the contact-friction energy dissipation properties from rate- independent aspect. Firstly， the parameter identification problem is simplified into a nonlinear least squares problem which can be solved by gradient algorithm， and the gradient response sensitivity analysis of Bouc-Wen model is carried out. Then， the hysteretic response of bolted structure is studied by finite element simulation. The Bouc-Wen model parameters are identified by response sensitivity method， and the effectiveness of the proposed method is verified. Finally， based on the quasi-static experimental study， the bolt-connected structure model is calibrated and used to predict hysteresis curves under other loads. The results show that the Bouc-Wen model can not only avoid the strong nonlinear and rigid equations caused by the discretization of the traditional Iwan model into Jenkins elements， but also can effectively characterize the hysteretic response of bolted structures.关键词：bolted joint;parameter identification;sensitivity analysis;hyteresis;Bouc-Wen model
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发布时间：2024-01-25 - 摘要：In order to enhance the performance of downlink non-orthogonal multiple access（NOMA） communication systems assisted by reconfigurable intelligent surfaces（RIS） in scenarios with non-uniform user distribution， a distributed user clustering scheme for downlink NOMA assisted by RIS has been proposed. Firstly， the adaptive geometric distribution （AGD） clustering algorithm is utilized to cluster users into user clusters （UCs） and match RIS with each UC. Then， the fractional programming （FP） method is employed to transform non-convex maximization and rate problems into convex optimization problems. Finally， power allocation （PA） and passive beamforming （PB） are performed sequentially for users within UCs. Simulation results demonstrate that， compared to spectral clustering （SPC）， K-means， Gaussian mixture model（GMM） clustering schemes and orthogonal multiple access （OMA）， the AGD scheme yields approximately 7%， 14%， 19% and 42% gains in power-to-spectral efficiency， while RIS contributes approximately 16%， 19%， 26% and 40% improvements in spectral efficiency.关键词：reconfigurable intelligent surface;non-orthogonal multiple access;user clustering;fractional programming
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发布时间：2024-01-25 - 摘要：Bayonet detector can obtain fine-grained information at individual traveler level， but it is difficult to achieve full coverage of the road network. Aiming at this problem， from the perspective of missing trajectory reconstruction， the bayonet layout optimization method for individual vehicle travel detection was studied. Considering the missing situation between two adjacent bayonet detection sequences， the methods of first reconstruction and second reconstruction of missing trajectory were proposed. Based on the principle of primary reconstruction， the flow capture rate and track coverage rate were created to measure the monitoring scale of road traffic information by bayonet layout scheme. Based on the principle of secondary reconstruction， the missing trajectory dispersion was created to measure the reliability of trajectory reconstruction. A bayonet layout optimization model for individual vehicle travel detection was constructed by taking traffic capture rate， trajectory coverage as constraints， and maximizing the dispersion of missing tracks as the optimization objective of bayonet layout. Particle swarm optimization algorithm was used to solve the optimization model. Taking a regional road network in Haizhu， Guangzhou as an example， the new layout and the added layout were analyzed respectively. The results showed that： in the new layout scene， the optimized bayonet layout scheme increased the phase flow capture rate by 6.20%， the track coverage rate by 2.76%， and the dispersion of missing track by 139%， which obtained better results than the current scheme in terms of individual vehicle travel track detection and reconstruction. In the added layout scene， the optimization solution of added 1-6 bayonets were carried out successively， and the added positions and optimization results were obtained.关键词：urban traffic;bayonet layout;particle swarm optimization（PSO）;individual travel detection;dispersion of missing trajectory
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发布时间：2024-01-25 - 摘要：By using fractional calculus， semigroup theories， inequality techniques and stochastic analysis theories， an averaging principle for Hilfer fractional impulsive stochastic evolution equations driven by fractional Brownian motion is established. The mild solution of the original equations converges to the mild solution of the reduced averaged equations without impulses in the mean square sense is proved. And an example is presented to illustrate the applicability of our obtained theoretical results.关键词：averaging principle;Hilfer fractional derivative;impulsive stochastic evolution equations;fractional Brownian motion
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发布时间：2024-01-25 - 摘要：The concepts of
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发布时间：2024-01-25 - 摘要：For the boundary value problem of Laplace equation in upper half plane， the sampling of
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发布时间：2024-01-25 - 摘要：The irreducible decomposition of unitary representations is investigated on the Hilbert space
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发布时间：2024-01-25
Research articles
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