In order to quantify the uncertainty of multi-energy flow distribution in the integrated energy system, a probabilistic multi-energy flow calculation method of integrated energy system based on data-driven is proposed. Firstly, a unified multi-energy flow calculation model suitable for different working modes of compressors in integrated energy system is established, and the impact of different operating modes of compressors on the multi-energy flow distribution is also discussed. Secondly, a probabilistic multi-energy flow calculation method based on support vector regression is developed. The method first constructs a data set by calculating deterministic multi-energy flow repeatedly, and then the support vector regression is used to mine the nonlinear mapping relationship between known loads, network node information and unknown node parameters in the integrated energy system. Finally, through case analysis, it is verified that the proposed unified multi-energy flow model can be applied to different compressor working conditions. By comparing with traditional probabilistic multi-energy flow calculation methods, it is shown that the proposed data-driven probabilistic multi-energy flow calculation method has higher computational accuracy and efficiency.

In order to address the problem that the parameter perturbation of interior permanent magnet synchronous motor leads to model uncertainty and affects the system control performance, an improved model-free sliding mode control method for interior permanent magnet synchronous motor based on nonlinear disturbance observer is proposed. Firstly, a new hyperlocal model of IPMSM considering parameter perturbation is established. Secondly, a sliding mode controller is designed as a feedback controller in model-free control by using the improved sliding mode reaching law. Then a nonlinear disturbance observer is designed to observe and estimate the model-free Unknown complex items in the control. Finally, a simulation comparison experiment is carried out with the traditional model-free sliding mode control method. The simulation experiment results prove that the proposed method can effectively solve the problems of system parameter perturbation affecting the motor control performance, with the effectiveness and superiority of the proposed method verified.

With the transformation of the national energy structure and the implementation of the “dual-carbon” strategy, large-scale wind power continues to be connected to the power system, which brings problems such as interactive resonance and converter drive stability to the system. By studying the influence of the control parameters of the machine-side converter and the outer ring of the grid-side converter control on the stability of doubly-fed asynchronous wind turbines, it is found that the parameter stabilization zones of the outer ring of the machine-side converter control are located in the lower left plane, and that the parameter stabilization zones of the outer ring of the grid-side converter control are located in the lower right plane, and that there exists a band of parameter risk areas between the parameter stabilization zones and the instability zones. When increasing the proportional and integral coefficients of the grid-side converter controllers, the system damping will be enhanced, but in a certain interval, a strong interaction and thus internal resonance will occur, leading to system destabilization. For the strong interaction between the controllers of the grid-side converter, Particle Swarm Optimization (PSO) is introduced to optimize the parameters of the PI controllers of the grid-side converter, and the optimization shortens the DC voltage recovery speed by half a cycle and reduces the overshooting amount by 40%.

For the randomness and dynamics problem of condition information and evaluation level boundary in the cable joint, an insulation state evaluation method of cable intermediate joint based on variable weight and interval number-set pair analysis theory is proposed. The partial discharge characteristic parameters of cable joint are extracted as the state evaluation index, and the index data are expressed in intervals. The variance and standard deviation are introduced to measure the volatility of the interval data of each index, and then the objective weight of the index is given. For the problem of unbalanced deterioration of partial discharge indicators, the corresponding state variable weight function is constructed to obtain the variable weight by comprehensively considering the deterioration degree and trend parameters of the indicators. Finally, the coupling method of interval number and set pair analysis is applied to obtain the state level of cable joint according to the expectation of comprehensive connection. By analyzing the online monitoring data of a 10 kV cable intermediate joint, the validity and feasibility of the state evaluation method are verified.

Reasonable task allocation and inspection routes are crucial for robots to replace engineers in performing inspection tasks in dangerous areas of substations. However, most existing studies focused solely on planning fixed shortest paths for inspecting power transformation equipment, neglecting the variability of equipment inspection times and the heterogeneity of inspection levels. To enhance the effectiveness and flexibility of substation inspections, this study establishes a dynamic inspection path planning model by comprehensively considering the variability of inspection times, the heterogeneity of equipment inspection levels, and the number differences equipments to be inspected. To address the NP-hard of the proposed model, this paper proposes a solution based on the reinforcement learning and multi-agent attention mechanism, which first generates inspection paths using an encoder-decoder framework with an attention layer, and then trains it using an unsupervised neural network. Finally, a substation of China Southern Power Grid is used as an experimental site to validate the model. Compared with the genetic algorithm (GA), Hierarchical Variable Neighborhood Search algorithm (HVNS) , and Adaptive Parallel Memetic Multi-Elite Ant System algorithm (APMMEAS) , the proposed algorithm reduces the path distances by 3.31%, 1.24%, and 1.73%, respectively; reduces the planning time by 17.06%, 16.22% and 13.89%, respectively; and reduces the single inspection costs by 21.22%, 6.86%, and 9.14%, respectively.

Carbon sink fisheries are an important means of producing blue carbon and contributing to carbon neutrality, with significant economic and environmental benefits. However, the implementation of carbon sink fisheries involves multiple parties and is a dynamic game. Existing studies have rarely analyzed carbon sink fisheries as an entry point to include governments, aquaculturists, and enterprises in the system at the same time. Against the background of the success of the pilot projects in Lianjiang and Putian, exploring blue carbon trading based on the perspective of carbon sink fisheries will help to provide scientific recommendations. Therefore, a tripartite evolutionary game model involving local governments, aquaculturists, and enterprises was constructed, and the impact of each subject's strategy choice on the stability of the system was analyzed. The results show that (1) subsidies for carbon sink fisheries have a dual effect on the evolutionary process. Within a certain range, moderate subsidies for carbon sink fisheries can motivate aquaculturists to shift to carbon sink fisheries, but too high subsidies level can cause a heavy financial burden and force the government to give up. (2) The difference between the price of subsidized blue carbon and the carbon tax is a key factor affecting the strategy choice of enterprises. When the price of subsidized blue carbon is lower than the carbon tax, enterprises tend to purchase blue carbon, and the lower the price of subsidized blue carbon, the faster the response of enterprises. (3) Based on the initial scenario, a moderate increase in the subsidy level of the local government can lead the three-party evolutionary game to the ideal outcome. Under this subsidy level, no matter what the initial probability of each party is, it will not affect the realization and continuation of the ideal outcome.

Water sources used for rural residential water in reservoirs of the southern Eucalyptus forest area are clearly exposed to natural melanogens such as tannins, ellagic acid and other polyhydroxyphenolic compounds and their iron salt complexes during autumn and winter, making it necessary to evaluate the effect of natural melanogens on human health. In this study, by simulating the natural melanogenic substances from reservoir waters in southern Eucalyptus forests with different concentrations of ellagic acid, trivalent iron were used to evaluate the general cytotoxicity, intracellular reactive oxygen species (ROS) levels, and cellular morphological changes after exposing to ellagic acid (EA) and/or trivalent iron (Fe³⁺) on colorectal adenocarcinoma epithelial cells (DLD1) , hepatocytes (LO2) , and human renal epithelial cells (293T) . The results showed cytotoxicity in most cases under both individual and combined exposure conditions. Cell viability was significantly reduced in the higher concentration of EA (1 mg/L, 10 mg/L) combined with 1 μmol/L Fe³⁺ treatment group, which was more toxic than EA exposure alone. The cell viability of LO2 and 293T cells did not change significantly in the combined exposure group, but they were decreased when compared with that of Fe³⁺ exposure alone. The results of oxidative stress assays found that both EA and/or Fe³⁺ exposure significantly increased ROS levels compared with DMSO controls. The ROS results for DLD1, LO2 may suggest that co-exposure had a greater effect on intracellular ROS secretion than when EA was exposed alone. In addition, no significant changes of cell morphology were observed in all treated groups, but the expression of actin F-actin in LO2 was significantly inhibited. The results of this study indicate that ellagic acid and trivalent iron exposure alone or in combination have deleterious effects on human cells, and the toxic effects in order are sorted as follows: hepatocytes (LO2) > intestinal cells (DLD1) > kidney cells (293T) . This study provided an important basis for the precise control of contaminants in southern rural water sources.

A method for determination of volatile sulfur compounds-dimethyl sulfide, diethyl sulfide, dimethyl disulfide, and carbon disulfide in livestock waste compost was established using gas chromatography–ion mobility spectroscopy technology. The sample was collected using a gas sampling bag after ammonia removal, separated on a packed gas chromatography column of MXT-1, and detected in both positive and negative modes under the optimized experimental conditions. The results showed that the four sulfur compounds represented good linearity (R²>0.99) in their respective linear ranges; the detection limits were 0.008~0.097 mg/m³ with recoveries of 85%~116% and relative standard deviation (RSD) of 1.13%~8.42%. The method is free of pretreatment such as pre-concentration or enrichment, sensitive and rapid, and the collection of odorous composting gas can be conducted using a gas sampling bag. The method is sensitive and rapid, which can be used for on-site monitoring of volatile sulfur in compost gas.

The urban heat island (UHI) has a significant impact on thermal comfort, energy, and ecological security. Accurately predicting the daily maximum urban heat island intensity (UHII_max) can provide early warning for energy consumption and ensure outdoor thermal safety. Based on the local climate zone (LCZ) framework, multiple LCZs were selected in Guangzhou, and long-term local climate observations were conducted over three years. The applicability of a diagnostic equation for daily UHII_max proposed by a European scholar, which did not consider anthropogenic heat flux (AHF) , was validated based on the observed results. Furthermore, the applicability of a revised equation considering AHF was tested in Guangzhou. The results showed that the diagnostic accuracy of the original equation was acceptable, with a correlation coefficient r² of 0.63, Root Mean Square Error (RMSE) of 1.50 K, Median Absolute Error (MEAE) of 0.97 K and d of 0.60. The revised equation considering AHF yielded more accurate diagnostic results than the original equation, with a decrease of 0.12 K in RMSE, a decrease of 0.10 K in MEAE, and an increase of 0.04 in d. The differences in the validation results of the equation across different LCZs indicate that the equation should be modified according to the characteristics of each LCZ. However, incorporating AHF can improve the diagnostic performance of the equation in all LCZs. In conclusion, the revised equation can be used to predict the development of UHI and improve diagnostic accuracy in hot and humid cities.

This paper studies the calculation of bending and torsional stiffness of wind turbine composite blades, as well as the numerical calculation method of shear stress on the hollow thin-walled section when the blade is subjected to transverse shear force. Modern wind turbine blades are slender and twisted, with thin-walled airfoil sections and complex internal topological configurations, and the materials are anisotropic. When applying various beam models for mechanical analysis such as blade aeroelastic calculation and strength check, the stiffness coefficient of the blade section and the calculation results of the section shear stress distribution are required parameters. Based on the composite thin-walled structure lamination theory and weighted average method, combined with the Bredt-Batho shear theory, a numerical analysis algorithm for the equivalent elastic constant and section stiffness coefficient of the composite laminate was established, taking into account the shear web effect of the composite blade. and warping effects; based on the plate and shell theory of elastic mechanics and considering the influence of transverse shear and section warpage on section deformation, a numerical calculation method for shear flow caused by transverse shear was established; a Matlab program for related algorithms was developed. By analyzing the main stiffness coefficient and shear flow distribution of a 10 MW wind turbine blade and comparing the literature results, the correctness of the model and the effectiveness of the algorithm are verified.

In the bearing-rotor system, rotor misalignment occurs from time to time, which has a great impact on the bearing performance. At present, most of the studies on gas foil bearings are two-dimensional models, which cannot consider the difference in axial deformation of bearings, so it is impossible to analyze rotor misalignment.. In this research, the shell theory is used to simulate the gas foil bearing, and the three-dimensional model is established. The shell element is used to model the top and bump foils, and the membrane, bending and shear effect are considered. The friction contact between bump and top foil is based on point-line contact, and the contact force is calculated by penalty function method. Due to the high nonlinearity of Coulomb friction model, in order to avoid the difficulty of numerical solution, it is regularized and solved by incremental iterative method. The results show that the model can simulate the structure of foil bearing effectively. When the rotor is not correct, the gas film thickness in the foil bearing will be distributed unevenly along the axis. The minimum film thickness decreases with the increase of the inclination Angle, and the inclination Angle almost does not affect the rotor eccentricity. The deformation of one end of the fop foil is much larger than that of the other end, which will reduce the bearing capacity of the foil, even cause damage.

Laser selective quantitative removal of CFRP represents a key technology for structural repair in the aerospace industry. However, the huge difference in properties between carbon fiber and epoxy resin in CFRP makes laser processing very challenging, and thermal damage has always been the main obstacle to the widespread application of CFRP laser processing. In order to study the influence of femtosecond laser processing parameters on the machining quality of CFRP, theoretical analysis and experimental verification were carried out by single factor experimental method. The influence of laser energy density, scanning speed and scanning direction on the ablation rate and the width of heat affected zone were analyzed, and the high-precision selective quantitative removal process of femtosecond laser on CFRP was investigated. The results show that when the process parameters are chosen to be θ = 90°, pulse width of 290 fs, power of 7 W, frequency of 100 kHz, scanning speed of 300 mm/s, and scanning spacing of 60～80 μm, the overall ablation surface quality is superior, and the accuracy (roughness) can be as high as 10 μm, and the heat-affected zone (HAZ) on the surface of the removed area is about 33.9 μm.

Based on the mode conversion theory of ultrasonic vibration, an ultrasonic torsion welding vibrator with a resonance frequency of 20 kHz is designed by combining the finite element method. The vibrator mainly consists of sandwich-type piezoelectric transducers and a mode conversion horn, with the mode conversion horn's mutual push rod and the vibration-transmitting rod connected by bolts. In order to reduce the leakage wave of the vibrator, a special structure vibration-dampening flange is designed to ensure torsional vibration at the output end of the mode conversion horn. The finite element analysis software is used for modal analysis and harmonic analysis. The torsional frequency of the simulated vibrator is 19.877 kHz, and the frequency response curve of the vibrator is obtained. The vibration mode conversion is completed at the mode conversion horn. Finally, the resonant frequency of the developed vibrator is 19.69 kHz measured by the impedance analyzer, which is less different from the theoretical value and simulation value. The longitudinal amplitude measured by the laser vibrometer at the end face of the mutual push rod of the vibrator is 10.2 μm, which is close to the simulation value. The feasibility of the design method is verified, and it can provide a reference for the design of other ultrasonic torsional welding vibrators.

Boundary value problems are a hot research area in the field of equation problems, with the study of boundary value problems for ordinary differential equations being quite mature. However, there is significant research space in solving boundary value problems when the known conditions are discrete points rather than given functions. Support Vector Regression (SVR) is a machine learning method based on statistical learning theory, which shows unique advantages in approximation problems by minimizing empirical risk while ensuring generalization capability. Therefore, this paper combines regularization, reproducing kernel theory, and SVR to investigate boundary value problems. Treating the boundary value problem as an operator equation problem, the relationship between the solution of the equation and the known conditions is obtained using the properties of reproducing kernel spaces. The problem is then transformed into an approximation problem, regularized into a quadratic programming problem, and solved using SVR to obtain a sparse solution composed of support vectors. Error analysis of the numerical solution obtained is conducted using norms in Sobolev spaces, providing an upper bound for the error between the numerical solution and the analytical solution. Taking a second-order three-point boundary value problem as an example, where only discrete values are given as known conditions for solving the equation, experimental results demonstrate that this method outperforms traditional reproducing kernel methods and W-POAFD methods, confirming its high accuracy and effectiveness.

The compact alternating direction implicit (ADI) scheme for two-dimensional Caputo-Hadamard fractional sub-differential equations is studied. Firstly, the Caputo-Hadamard fractional derivative on exponential type meshes is approximated. Secondly, in order to solve the high-dimensional problems, a compact ADI method is proposed. With the help of mathematical induction and the properties of discrete coefficients, the stability and convergence of the proposed scheme are analyzed. Ultimately, an example is presented to show the effective of our analysis.

Due to the significant applications of the Kirchhoff equation in numerous physical problems, the issue of normalized solutions has gradually attracted the research interest of a large number of scholars in recent years. These studies focus on exploring the existence of normalized solutions to equations, specifically, whether solutions that satisfy the equations can be found under certain mass constraint conditions. An investigation is conducted into the existence of normalized solutions for a class of Kirchhoff equations with combined nonlinear terms. By utilizing the minimization method in variational calculus, along with the concentration compactness principle and the vanishing lemma, it has been proven that under diffusion conditions with arbitrary mass constraints, the equation possesses a normalized solution. Comparing with existing results, the conclusions of the research serve as an extension of existing related results.