On a power-type coupled system of Monge-Ampère equations

We study an elliptic system coupled by Monge--Amp\`{e}re equations:$$\begin{cases}      \det D^{2}u_{1}={(-u_{2})}^\alpha & \hbox{in  $\Omega,$} \\      \det D^{2}u_{2}={(-u_{1})}^\beta & \hbox{in $\Omega,$} \\      u_{1}<0,\ u_{2}<0& \hbox{in  $\Omega,$}\\     u_{1}=u_{2}=0 & \hbox{on $ \partial \Omega,$}   \end{cases}$$%here $\Omega$~is a smooth, bounded and strictly convex domainin~$\mathbb{R}^{N}$, $N\geq2$, \alpha >0, \beta >0. When $\Omega$ isthe unit ball in $\mathbb{R}^{N}$, we use index theory of fixedpoints for completely continuous operators to get existence, uniqueness results and nonexistence of radial convex solutions undersome corresponding assumptions on $\alpha$, $\beta$. When \alpha>0,\beta>0 and $\alpha\beta=N^2$  we also study a~corresponding eigenvalue problem in more general domains

Nontrivial convex solutions for systems of Monge-Ampere equations via global bifurcation

We obtain existence results for some systems of Monge-Ampere equations, using bifurcation theorems of Krasnosell'ski-Rabinowitz type

Distributed economic operation strategy of charging stations based on consistency algorithm

Considering that the centralized optimization control strategy is difficult to adapt to the access of large-scale electric vehicles, a distributed collaborative control strategy based on consensus algorithm is proposed in this paper to control the operation of multiple charging stations. In order to reduce the computational cost, a charging station aggregation model is established to reduce the optimization variables of large-scale electric vehicle access. According to the dispatching instructions issued by the distribution network, this method takes the economic operation of charging stations as the goal, satisfies the global and local constraints, and realizes the power allocation among charging stations. The case analysis proves the accuracy, effectiveness and robustness of the method, and the adaptability to large-scale electric vehicle access

The Optimized Roadway Layouts and Surrounding Rock Control Technology of the Fully Mechanized Mining Surface with Large Mining Heights in High-Gas Mines

Many problems exist in the layout of working surfaces in high-gas mines, such as the low efficiency of roadway excavation, difficulties in maintenance after excavation, and serious resource wastes due to difficulties in recovering coal pillars between roadways. Taking the project profile in the west wing mining area of Sihe Coal Mine as the background, this work proposed an optimization plan for the staggered-layer arrangement of roadways. The minimum retained size of the coal pillar was calculated through theoretical analysis, and the plastic failure and deformations of surrounding rocks under different coal pillar sizes and roadway layouts were compared based on finite difference numerical simulations. The reasonable retained size of the coal pillar was determined to be 45 m, and the roadway layout was determined according to the distribution of coal and rock strata in the mining field. The technical measures of base angle pressure relief blasting and strengthening support were proposed to ensure the safety and stability of surrounding rocks of roadways during the service period after the layout plan was optimized. Similar simulation tests were used to study the damage deformations and stress changes of the blasting pressure relief floor. On-site tests showed that the optimized roadway layout greatly improved the recovery rate of coal resources. In addition, surrounding rocks had good stability, and they could be simply repaired or serve the next working surface directly without being repaired. These research results provide a scientific basis and useful reference for similar projects

Overlying Strata Movement and Mine-Pressure Weakening Law of High-Efficiency Longwall Paste Backfilling of Thick Coal

This work focused on the serious coal compression under buildings, railways, and water bodies in central and eastern China; the wide range of rock formation damage during the collapse mining process; the high pressure of mines; and difficulties in controlling surface subsidence after mining. The E1302 working face of Shanxi Gaohe Energy was taken as the engineering background in the work. The mechanical properties of gangue paste-filling materials were studied through laboratory tests, and the critical conditions for bending and fracture of the coal seam roof were analyzed. Discrete-element numerical simulation software was used to study the fracturing process of the roof, and the reasonable filling rate to ensure roof stability was determined to be 95%. Meanwhile, overlying stratum movement and mine-pressure weakening law were studied through numerical simulations and field measurement. The results showed that fracture development during the mining process of thick-coal paste filling was divided into the advanced development, re-compaction, and steady-state maintenance of fractures. Fractures advanced in a “sail shape” and developed only in the main-roof rock strata after recompaction. The maximum subsidence angle of the working face was 87.13° after mining, with a subsidence factor of 0.034 and a maximum horizontal movement coefficient of 0.71. The advanced stress value was weakened by 40%, and the influenced area was reduced by 13%. Overlying stratum movement was controlled, and mine pressures were significantly weakened. The work can provide a scientific basis for green backfill mining, roadway support design, and backfill mining equipment selection

Design of a composite metamaterial toward perfect microwave absorption and excellent load-bearing performance

In this paper, an ultrathin layer of arrayed electromagnetic resonators is introduced on the CFRP laminate to form a meta-CFRP composite. It is quite an exciting and promising design, as the composite metamaterial not only inherits the advantages of the CFRP composite in mechanical performance but can also obtain on-demand microwave absorption properties rather than purely reflective as neat CFRP laminates. Here, several meta-CFRP samples have been prepared by a co-curing process. Near-perfect microwave absorption (i.e., S11 ≤ -10 dB) has been achieved in a series of situations such as under normal incidence and a constant polarization angle, under oblique incidence and an arbitrary polarization angle, and for a relative broadband microwave absorption (11.28 GHz ∼ 12.52 GHz). Moreover, the mechanical properties of the fabricated meta-CFRP samples, including tension, compression, bending, and shear, have also been investigated, which showed an increase of more than 680% compared with previous microwave absorbers. The present work provides a new idea for designing electromagnetic and mechanical dual functional materials, based on which many new materials, for example, strong materials with tunable microwave absorption, can be further developed in the future

Integrated transcriptome and metabolome analysis provides insights into blue light response of Flammulina filiformis

Abstract Blue light promotes primordium differentiation and fruiting body formation of mushroom. However, the blue light response mechanism of mushroom remains unclear. In this study, mycelium of Flammulina filiformis was exposed to blue light, red light and dark conditions, and then the comparative metabolome and transcriptome analysis was applied to explore metabolic regulation mechanism of F. filiformis under blue light and red light conditions. The yield of the fruiting body of F. filiformis under blue light condition was much higher than that under dark and red light conditions. Metabolome analysis showed that blue light treatment reduced the concentrations of many low molecular weight carbohydrates in the pilei, but it promoted the accumulation of some low molecular weight carbohydrates in the stipes. Blue light also decreased the accumulation of organic acids in the stipes. Blue light treatment reduced the levels of tyrosine and tryptophan in the stipes, but it largely promoted the accumulation of lysine in this organ. In the stipes of F. filiformis, blue light shifted metabolite flow to synthesis of lysine and carbohydrates through inhibiting the accumulation of aromatic amino acids and organic acids, thereby enhancing its nutritional and medicinal values. The transcriptome analysis displayed that blue light enhanced accumulation of lysine in fruiting body of F. filiformis through downregulation of lysine methyltransferase gene and L-lysine 6-monooxygenase gene. Additionally, in the stipes, blue light upregulated many hydrolase genes to improve the ability of the stipe to biodegrade the medium and elevated the growth rate of the fruiting body

A city-level dataset of heavy metal emissions into the atmosphere across China from 2015–2020

Abstract The absence of nationwide distribution data regarding heavy metal emissions into the atmosphere poses a significant constraint in environmental research and public health assessment. In response to the critical data deficiency, we have established a dataset covering Cr, Cd, As, and Pb emissions into the atmosphere (HMEAs, unit: ton) across 367 municipalities in China. Initially, we collected HMEAs data and covariates such as industrial emissions, vehicle emissions, meteorological variables, among other ten indicators. Following this, nine machine learning models, including Linear Regression (LR), Ridge, Bayesian Ridge (Bayesian), K-Neighbors Regressor (KNN), MLP Regressor (MLP), Random Forest Regressor (RF), LGBM Regressor (LGBM), Lasso, and ElasticNet, were assessed using coefficient of determination (R2), root-mean-square error (RMSE) and Mean Absolute Error (MAE) on the testing dataset. RF and LGBM models were chosen, due to their favorable predictive performance (R2: 0.58–0.84, lower RMSE/MAE), confirming their robustness in modelling. This dataset serves as a valuable resource for informing environmental policies, monitoring air quality, conducting environmental assessments, and facilitating academic research