最新刊期
卷 64 ， 期 2 ， 2025
- 摘要：In the study，lateral compression and creep tests were performed on calcareous sands of varying particle sizes using a self-designed acrylic model box. The research focused on investigating the compression deformation， characteristics of particle breakage， and the evolution of internal stress in calcareous sand under various stress levels. The results indicate that when vertical stress is relatively low， the compression deformation， creep strain， and creep rate of calcareous sand decrease as particle size increases. Conversely， under higher vertical stress， these variables increase with particle size. This behavior is attributed to the fact that the deformation of calcareous sand is controlled by the rearrangement of particle positions and the extent of particle breakage. At low vertical stress， particle breakage is minimal and can be overlooked； as the particle size of calcareous sand increases， the irregularity of particle shapes also increases， which enhances inter-particle locking and thus suppresses deformation. However， as vertical stress increases， considerable particle breakage occurs in calcareous sand； moreover， larger particle sizes lead to more significant particle breakage. This exacerbates deformation， alters the particle contacts， and intensifies stress redistribution. Consequently， the distribution of vertical and lateral stresses within the calcareous sand shifts from a Weibull distribution to a normal distribution. During the creep process， the internal stress distribution of calcareous sand tends to become uniform.关键词：calcareous sand;particle breakage;creep;particle size;distribution of stresses215|151|0更新时间：2025-11-14
- 摘要：Based on the annual maximum daily precipitation data collected from 30 meteorological observation stations in the Guangdong-Hong Kong-Macao Greater Bay Area between 1961 and 2023， the optimal distribution function and recurrence design level of extreme precipitation frequency in each sub-region of the Greater Bay Area were analyzed by using the regional linear moment method. The findings are summarized as follows： 1） The meteorological stations in the Greater Bay Area are divided into five sub-regions by KNN classification and homogeneity criterion. These sub-regions are： Region Ⅰ， located in the middle and lower reaches of the Xijiang River； Region Ⅱ， located in the Delta network River Area in the central and northern part of the Greater Bay Area； Region Ⅲ， located on both sides of the Lingdingyang Estuary Area in the southern part of the Greater Bay Area； Region Ⅳ， located in the southwestern part of the Greater Bay Area； and Region V， located in the eastern part of the Greater Bay Area. 2） The optimal distribution functions of the 1st to 5th sub-regions are P-III， GEV， GEV， P-III， and GEV， respectively. Consequently， the rainstorm frequency design values of each station in the Greater Bay Area are calculated using the regional rainstorm growth curve method. 3） The rainstorm recurrence level determined by the optimal distribution functions for the five sub-regions can serve as a reference for engineering design in sub-regions that lack specific site data.关键词：L-moment;regional extreme precipitation;frequency analysis;KNN classification;regional optimal distribution functions168|125|0更新时间：2025-11-14
- 摘要：Identifying the factors that influence regional water use and the corresponding regulations is crucial for accurately predicting water demand and optimizing the allocation of water resources. This study collected historical data on water resource exploitation and socio-economic statistics in the Pearl River Delta （PRD） region. Two machine learning models， namely Random Forest （RF） and Artificial Neural Network （ANN）， were employed to systematically identify the factors affecting water use and to uncover the associated rules in the PRD region. In addition， Shapley Additive Explanations （SHAP） and Partial Dependence Plots （PDP） were applied to enhance the interpretability of the modeling outcomes. The results indicate that the factors influencing water use， in order of importance， are GDP， population size， cultivated land area， per capita water resources， water consumption for actual irrigation per unit of farmland， and urban per capita domestic water use. The average determination coefficients of ANN and RF models are above 0.94 and 0.92， respectively. Regarding water use factors， population is the dominant influence in the central cities， while cultivated land is the principal factor in the surrounding areas. Water use in the PRD region shows the most significant response to the changes in population size and cultivated land area. This research provides a scientific basis and technical support for the future prediction of water demand and the balanced allocation of water resources in the PRD region.关键词：artificial neural network;random forest;water consumption;SHAP method;PDP130|125|0更新时间：2025-11-14
- 摘要：Soil porosity is a crucial parameter in the study of soil physical quality， agriculture， and environmental protection. This research focuses on the 0-20 cm surface soil of tobacco planting in Baise， Guangxi Province. Four machine learning models were employed to simulate the predictive potential of six climatic factors， three topographic factors， and one soil attribute factor on soil porosity. The study also analyzed the magnitude and spatial distribution characteristics of porosity. The findings reveal that the Random Forest model is the most effective， achieving a mean porosity prediction value of 41.257%， the lowest root mean square error of 5.738， and the highest coefficient of determination of 0.648. The predicted results closely align with the measured values， indicating that the Random Forest model demonstrates strong generalization performance and effective predictive capabilities for simulating environmental factors and soil porosity. Meanwhile， results from Kriging interpolation indicate that the porosity values in Debao County and Jingxi City areas are generally low. This suggests potential land degradation issues， such as land slumping， compaction， and a reduction of soil organic carbon storage. These problems could be mitigated through restoration measures such as selective operation， the reasonable application of organic fertilizer， and deep plowing， which would help promote tobacco productivity in the study area. Overall， this study provides an effective method for predicting regional soil porosity and offers a valuable reference for understanding the characteristics of soil porosity in tobacco-growing regions across the country， as well as for developing land degradation management strategies.关键词：soil porosity;climate factors;topographic factors;soil property factors;random forest model158|109|0更新时间：2025-11-14
- 摘要：The Ili River Basin is one of the best-preserved arid and semi-arid ecological landscapes in Central Asia， its vegetation coverage affects the regional ecological balance and climate change. Based on the MODIS NDVI dataset and the binary pixel model， the Hurst index and BFAST model are used to analyze the spatiotemporal changes and persistence of the Fractional Vegetation Cover （FVC） in the Ili River Basin from 2001 to 2022. The results are as follows： 1） Over the past 22 years， the vegetation coverage in the Ili River Basin has generally shown a fluctuating upward trend. The average vegetation coverage from 2001 to 2022 was 0.18， with low vegetation coverage being the main feature. The distribution of vegetation has significant spatial variability， with the vegetation coverage in the upstream and midstream areas being significantly higher than that in the downstream areas. 2） The BFAST model analysis shows that the increase and degradation of vegetation coverage in the Ili River Basin accounted for 47.3% and 52.7% respectively. The trend of vegetation degradation is slightly higher than that of vegetation growth. The Hurst index indicates that the future vegetation increasing trend accounts for 62.42% while the decreasing trend accounts for 16.84%. The superposition of 17 results from the BFAST model and Hurst index analysis shows that the future trend of vegetation coverage has an increasing trend of 65.22%， which is much greater than the decreasing trend （15.07%） and the unpredictable areas of 19.71%. Overall， the future vegetation shows an increasing trend. 3） Geodetector-based analyses show that precipitation， and temperature have the greatest influence on vegetation cover in the whole basin. For each sub-region， the topography of the upper reaches is dominated by river valleys， and the main influencing factor is altitude； while in the middle reaches， temperature and GDP are two dominant factors； in the lower reaches， temperature and precipitation are dominant. The results of this paper provide scientific and technical support for the ecological balance of the Ili River Basin and future trends in vegetation change.关键词：vegetation coverage;pixel bisection model;Hurst index;BFAST model;Ili River Basin398|283|0更新时间：2025-11-14
- 摘要：Based on the theory of urban recreation and the data of point-of-interest （POI） in Guilin City， this paper investigates the urban recreation space form of Guilin City by means of the nearest neighbor index， the average distance between the city center and the spatial dispersion， the radius of rotation， and the kernel density estimation. The study found： 1） The recreation space of Guilin presents a spatial distribution pattern dominated by natural tourism resources， and the recreation points are gathered in the city center and Yangshuo， Xing’an， and Lingui. There are significant differences in the number of recreation points among counties， among which public and cultural recreation points are more prominent. Recreation points form two large-scale cores in the city center and Yangshuo County， and there is an axial distribution pattern between them and other small and medium-sized cores. With Guilin city center and Yangshuo County as development cores， they spread to surrounding counties under the influence of agglomeration effect， and form a development axis between the two cores. The spatial distribution pattern of ‘one-axis double-core’ is formed. 2） As a natural resource-based tourism city， Guilin’s abundant local tourism resources have laid the foundation for its tourism industry. It relies on the tourism value brought by natural resources to carry out economic development. Driven by the spatial distribution of natural tourism resources and the recreational demands of local residents， the city center has gradually formed with Xiangbi Mountain， two rivers， and four lakes as the center. At the same time， Yangshuo， Xing’an， and Longsheng with relatively concentrated natural tourism resources have gradually become multiple growth cores of economy and tourism in Guilin after a long period of development of tourism resources， forming a new pattern of ‘11235’ global tourism city with the central Guilin. 3） Guilin’s urban recreation space form is the tourism center， and through the development mode of tourism urbanization， the recreation space structure of the current urban center has been formed. Based on POI data， the study analyzed the recreation space form of Guilin， a typical natural tourism city， to understand the formation of the urban recreation space of this model， and to a certain extent supplement the gap in the study of this kind of urban development mode in China.关键词：urban recreation;spatial formation;POI data;Guilin City108|150|0更新时间：2025-11-14
- 摘要：Utilizing ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry （UFLC-QTOF-MS/MS） technology， and employing the larvae of mealworm （Tenebrio molitor） as a model organism， this study developed a new approach to discover and accumulate chromatographic-mass spectrometric characteristic data of metamifop metabolites in the absence of comprehensive metabolite standards. The metabolic pathway of metamifop in T. molitor was further elucidated. The study identified 21 metabolites in the excreta of mealworms larvae that were fed a diet containing 2 mg/g of metamifop over a period of 15 days. These included 14 phase I metabolites and 7 phase Ⅱ metabolites. Among the phase I metabolites， beside the reported compounds such as Metamifop monooxide， Fenoxaprop acid， 6-CBO， HPFMPA， HPPA， and HFMPA， eight were identified for the first time in any biological system. It was also observed that these phase I metabolites underwent transformation into corresponding phase Ⅱ metabolites through three primary pathways： Conjugation with amino acids， glucose-sulfate esterification， and sulfation.关键词：metamifop;Tenebrio molitor;metabolite;UFLC-QTOF-MS/MS249|212|0更新时间：2025-11-14
- 摘要：The enantiomerism mechanism of chiral enantiomers of calcium diatomic valine （Val·Ca2+） was studied by using the hybrid exchange functional method of M06-2X and MN15 based on DFT （density functional theory） and SMD model method with self-consistent reaction field theory under physiological environment ［（aqueous liquid phase， 310.15 K and 1.013×105 Pa （1 standard atmosphere）］. The observations on reaction channels found that the enantiomerism of Val·Ca2+ can be achieved by using carbonyl O or amino N as H proton transfer bridge. The energy diagram calculation of stagnation point in enantiomerism process showed that the enantiomerism process of proton H using N atom as bridge migration has advantages. Under the effect of water polarity and water molecules （clusters）， the energy barrier of velocity determination step of the dominant reaction channel is between 118.6 and 121.9 kJ/mol. The results show that the enantiomerism rate of calcium diatomic valine complexes is very slow in physiological environment， and it is safe to supplement calcium bivalent ion and valine in living organisms.关键词：calcium bivalent valine;solvent effect;density functional theory;enantiomerism;reaction energy barrier67|42|0更新时间：2025-11-14
- 摘要：This paper proposes a road network topology model of parking lot in the form of virtual arc. First， determine the road where the parking space is located and the projection point of the parking center on the road. Then， the segmentation position is confirmed by the ratio of the length of the sub-road on both sides of the projection point to the total length of the road. For each parking space， a part of the road is intercepted by the segmentation position as a virtual arc to express the topological relationship between the parking space and the road network. Finally， the path planning is divided into two stages： from the starting point to the endpoints of the road where the parking space is located， and from the endpoints to the parking space. The one with the lower comprehensive cost will be chosen as the final path. The experimental results show that the computational time is saved by more than 70%， the number of topological nodes and edges is reduced by more than 90%， the storage space is saved by 20%. It is proved that the model is of great significance to reduce the time of route finding， the workload of maintaining topological network and the pressure of data storage and transmission.关键词：topology network;virtual arc;parking lot;parking guidance186|240|0更新时间：2025-11-14
- 摘要：We investigated the modification of three types of nanoenzymes（Au24Cd1，Au24Er1，and Au25） on Ag microelectrodes（AgME），Au microelectrodes（AuME），and electrocorticography microelectrode（EcoGME）. In this study， three distinct nanoenzymes were successfully immobilized onto the surfaces of three different electrodes. The electrodes modified with nanoenzymes mitigated the inherently high impedance characteristic of conventional neuroelectrodes. Meanwhile， we investigated the effect of nanoenzymatic modifications on different electrochemical recording methods， including electrochemical impedance spectroscopy， cyclic voltammetry， differential pulse voltammetry， square wave pulse voltammetry， normal pulse voltammetry and linear scanning voltammetry. By investigating the effects of various nanoenzyme materials，electrode substrates，and detection methods in neural signal acquisition applications，the findings provide more precise and efficient sensing options for neuroscience research and clinical practice.关键词：nanoenzyme;implantable microelectrodes;electrochemical detection305|484|0更新时间：2025-11-14
- 摘要：A study on the unsteady kerosene spray field of subsonic combustor evaporative flameholder was carried out. The Euler-Lagrange method is used to realize the two-way coupling of turbulent air and discrete droplet， and the effect of dielectric barrier discharge plasma on the flow field is simulated by volume force. The research results indicate that dielectric barrier discharge plasma actuation with different actuation position， actuation voltage and actuation frequency can control the flow field in the recirculation zone after the flameholder， the kerosene spray field and the mixing of kerosene and air through changing the local momentum of the fluid. The optimal actuation parameters corresponding to the specific flow conditions can often be determined. Specifically， under the conditions of incoming flow studied in this paper， applying plasma actuation with a voltage of 15 kV and a frequency of 15 kHz at the front section outside the flameholder wall can increase the length of the recirculation zone and the area of the low-speed region behind the flameholder， improve the kerosene atomization and evaporation， promote the mixing of fuel and oxidizer， prolong the residence time of the combustible mixture， and thereby facilitate reliable ignition and sustain stable combustion.关键词：evaporative flameholder;kerosene spray field;control;dielectric barrier discharge;plasma actuation148|251|0更新时间：2025-11-14
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Comparison of structural vibration measurement based on intensity-based and phase-based optical flow
摘要：Phase-based optical flow method firstly obtains the local phase information of the image through wavelet filtering， and then estimates the displacement of structures with phase gradient and phase change. It has good robustness to illumination change and image noise， and has a certain improvement in the measurement range compared with the traditional intensity-based optical flow method. Several simulation experiments were designed for image noise and illumination change respectively. The measurement errors of the two methods were compared under different sizes of displacement. Those results show that the phase-based optical flow method has better measurement effect when there is more than 1 pixel displacement， noise and illumination change. Finally， two methods are used to estimate the motion of the simulated and actual cantilever beam vibration video， and the validity of the two methods and the superiority of phase-based optical flow method in the estimation of structural micro-vibration is verified.关键词：image displacement estimation;intensity-based optical flow;phase-based optical flow;micro displacement213|284|0更新时间：2025-11-14 - 摘要：The macro-micro mechanical relationship of Green sandstone was established by indoor experiments and microscopic parameter calibration. The mechanical properties， crack evolution law， and energy utilization efficiency under different loading rates were analysed. The results showed that：（1）When the loading rate is less than 0.1 m/s， the stress-strain curve shape of the Green sandstone is basically consistent，and the smaller the loading rate， the more significant the Brittle failure. The tension chain is the main cause of crack propagation and extension，and the ultimate fracture is the result of the interaction between pressure and tension chains.（2）The fracture morphology of green sandstone can be divided into the failure way dominated by the main crack， the failure way where secondary cracks appear， and the failure way where secondary cracks penetrate. With the increase of loading rate， the number of cracks and the number of fracture elements in Green sandstone show a similar trend.（3） The loading rate is 0.000 5~0.1 m/s， and the input energy fracture energy curve shows up and down fluctuations， but the fluctuation range is small； When the loading rate is 0.5~1 m/s， the input energy shows a nearly linear increase trend， the fracture energy shows a rapid increase， and then a slow trend. The energy utilization efficiency is mainly concentrated in 10.262%~11.511%.关键词：Green sandstone;loading rate;brazil splitting;tensile properties;fracture energy125|241|1更新时间：2025-11-14
- 摘要：A deep learning image detection model based on You Only Look Once-Double Spatial-Squeeze Module （YOLO-DSM） is proposed. First，the Hierarchical Mixed-scale Unit （HMU） module is introduced after each Dark module to improve the detection accuracy of target defects on TFT-LCD panels. The original Spatial Pyramid Pooling（SPP） is replaced with Simple Spatial Mlp Attention（SSMA） to enable the network to focus more on targets with low contrast against the background. Second， the Double Spatial-Squeeze Module（DSM） is introduced to help the network enhance useful features and suppress useless ones， thereby enhancing the integration of semantic information. Finally， the Omni-dimensional Dynamic Convolution（ODConv） module replaces the down-sampling convolution of the original network to refine local feature mapping and achieve full extraction of local defect features. In comparative experiments on a self-made TFT-LCD defect dataset， the YOLO-DSM network achieved an mAP accuracy of 97.40% and an FPS of 77.42 frames. This meets the requirements of TFT-LCD defect detection tasks.关键词：visual micro-defects;YOLO-DSM;omni-dimensional dynamic convolution;spatial and channel squeeze & excitation206|208|0更新时间：2025-11-14
- 摘要：A class of Choquard type coupled systems are considered， where Hardy-Littlewood-Sobolev critical exponents and logarithmic terms are contained in nonlinear terms. If the coefficients of logarithmic terms are both negative， Palais-Smale sequences of the energy functional corresponding to above problems in Nehari manifold are established by using of the existence on a local minima of single critical Choquard equation. Furthermore， by adopting Ekeland’s variational principle， some restricted conditions under which the parameters are related to the first eigenvalue of linear operator with Dirichlet boundary conditions are given. The nonnegative solution with negative energy level of above systems is obtained. Our work generalizes the cases that the coefficients of logarithmic terms are positive， and analyzes the impact of negative coefficients on geometry structure of the energy functional. In fact， our results extend classical Sobolev critical systems to the corresponding Choquard problems.关键词：Choquard systems;logarithmic terms;ground state solutions;critical exponents;coupled terms117|46|0更新时间：2025-11-14
- 摘要：According to the known mechanism of mumps transmission， a SVEIAR mumps infectious disease model with vaccination and incubation period was established by using the qualitative and stability theory of ordinary differential equation， and the basic regeneration number of the model was obtained. The existence of the equilibrium points is given and it is found that the disease-free equilibrium point is globally asymptotically stable when
- 摘要：The boundness and compactness of products of multiplication, composition and differentiation on weighted Bergman spaces in the unit ball are studied. We define the differentiation operator on the space of holomorphic functions in the unit ball by radial derivative. Then we extend the Sharma's results.关键词：composition operator;multiplication operator;differentiation operator;weighted Bergman space132|149|0更新时间：2025-11-14
- 摘要：The existence，uniqueness and exponential stability of mild solutions of stochastic elastic systems with damping and infinite delay are studied in Hilbert spaces. By using the theory of operator semigroups， properties of axiomatic phase space and stochastic analysis， the existence and uniqueness of mild solution and the exponential stability in mean square are obtained， the existing results of damping elastic systems are enriched and developed.关键词：stochastic elastic systems;mild solutions;exponential stability;damping;operator semigroups97|88|0更新时间：2025-11-14
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