HRTEM Analysis of the Influence of Non-stick Coal's Oxidation Degree on Aromatic Fringe Morphology.

The purpose of this research was to explore the parameters of the aromatics lattice fringes by using high resolution transmission electron microscopy (HRTEM) patterns, combined with ArcGIS and MATLAB methods, to quantitatively evaluate and analyze the coal samples oxidized by different concentrations of H2O2, and to explore the changes in the morphology and spatial distribution of the aromatic system under oxidation. As the degree of oxidation increased, the orientation of the aromatic lattice fringes became more disordered, and the distortion degree increased. The distribution range of Y and T type dislocation structures, which were widely distributed in short (<0.59 nm) lattice fringes, increased, while that of spiral type dislocation structures, which were distributed in medium (0.59-0.99 nm) and long (1.00-2.49 nm) lattice fringes, decreased. In addition, the collapse and condensation of aromatic slices caused by continuous oxidation further weakened the π-π stacking effect between aromatic rings, resulting in a decrease in the interlayer distance and stacking height. The advantages of HRTEM analysis were confirmed by XRD, SEM and FTIR analysis. This provides a new perspective on the oxidation phenomenon and enriches the examination of the low-temperature oxidation mechanism of coal.

Molecular Mechanism Study on the Effect of Microstructural Differences of Octylphenol Polyoxyethylene Ether (OPEO) Surfactants on the Wettability of Anthracite.

Inhalable coal dust poses a serious threat to coal mining safety, air quality, and the health of miners. Therefore, the development of efficient dust suppressants is crucial for addressing this issue. This study evaluated the ability of three high-surface-active OPEO-type nonionic surfactants (OP4, OP9, and OP13) to improve the wetting properties of anthracite via extensive experiments and a molecular simulation and determined the micro-mechanism of different wetting properties. The surface tension results show that OP4 has the lowest surface tension (27.182 mN/m). Contact angle tests and wetting kinetics models suggest that OP4 exhibits the strongest wetting improvement ability on raw coal with the smallest contact angle (20.1°) and the fastest wetting rate. In addition, FTIR and XPS experimental results also reveal that OP4-treated coal surfaces introduce the most hydrophilic elements and groups. UV spectroscopy testing shows that OP4 has the highest adsorption capacity on the coal surface, reaching 133.45 mg/g. The surfactant is adsorbed on the surface and pores of anthracite, while the strong adsorption ability of OP4 results in the least amount of N2 adsorption (8.408 cm3/g) but the largest specific surface area (1.673 m2/g). In addition, the filling behavior and aggregation behavior of surfactants on the anthracite coal surface were observed using SEM. The MD simulation results indicate that OPEO reagents with overly long hydrophilic chains would produce spatial effects on the coal surface. Under the influence of the π-π interaction between the hydrophobic benzene ring and the coal surface, OPEO reagents with fewer ethylene oxide quantities are more prone to adsorb onto the coal surface. Therefore, after the adsorption of OP4, both the polarity and the water molecule adhesion ability of the coal surface are greatly enhanced, which helps to suppress dust production. These results provide important references and a foundation for future designs of efficient compound dust suppressant systems.

Molecular mechanism study on the effect of nonionic surfactants with different degrees of ethoxylation on the wettability of anthracite.

A serious risk to the production safety of coal mines is coal dust. The wettability of coal may be successfully changed by adding surfactants to water. However, the creation of very effective dust suppressants is constrained by the lack of knowledge about the microscopic interaction mechanism between coal dust and surfactants. In this investigation, we explained macroscopic experimental phenomena from a molecular perspective. The lauryl polyoxyethylene ethers (C12 (EO)n, n = 7,15,23) were selected. The macromolecular model of anthracite with 55 different components was constructed. Surface tension experiments and hydrophilic lipophilic balance (HLB) calculations showed that the ability of surface hydrophilicization followed the order of C12 (EO)7

Explicating the responses of NDVI and GDP to the poverty alleviation policy in poverty areas of China in the 21st century.

The economy in the poverty-stricken areas of China has grown rapidly in response to poverty alleviation policies in the 21st century. To explicate the response of the eco-environment to rapid economic growth in the 14 contiguous areas of dire poverty in China, we developed a method of evaluating the impact of poverty alleviation policies on ecological health. Based on the yearly data of gross domestic product (GDP) per capita and normalized difference vegetation index (NDVI) from 2000 to 2019, the dynamic changes in NDVI and GDP were calculated, and the development patterns in the 14 contiguous areas of dire poverty were evaluated and classified. The results show that both annual GDP per capita and average annual NDVI exhibited an increasing trend, increasing by 43.81% and 0.84% per year, respectively. The development of the 14 contiguous areas of dire poverty all presented a coordinated and sustainable (A) development pattern during the period from 2000 to 2019. The consistency of economic and ecological health development between 2000 and 2013 was less than that between 2014 and 2019. Moreover, the result indicates that it is necessary to make timely adjustments to poverty alleviation strategies based on the positive consistency between economic growth and ecological health.

Adsorption Characteristics of Ionic Surfactants on Anthracite Surface: A Combined Experimental and Modeling Study.

Ionic surfactants are widely used in coal dust control in mines, and their adsorption characteristics on the coal surface have a great influence on the coal dust control effect. In this investigation, anionic sodium dodecylbenzenesulfonate (SDBS) and cationic octadecyltrimethylammonium chloride (STAC) were selected to explore the adsorption characteristics of ionic surfactants on the surface of anthracite. The experimental results show that the adsorption rate and efficiency of STAC on the surface of anthracite are higher than that of SDBS; STAC can form a denser surfactant layer on the surface of anthracite, with a larger adsorption capacity and higher strength. Molecular dynamics simulations show that the adsorption between STAC and the surface of anthracite is tighter, and the distribution at the coal-water interface is more uniform; the surface of anthracite modified by STAC has a stronger binding ability to water molecules.

Voxel-Mesh Network for Geodesic-Aware 3D Semantic Segmentation of Indoor Scenes.

In recent years, sparse voxel-based methods have become the state-of-the-arts for 3D semantic segmentation of indoor scenes, thanks to the powerful 3D CNNs. Nevertheless, being oblivious to the underlying geometry, voxel-based methods suffer from ambiguous features on spatially close objects and struggle with handling complex and irregular geometries due to the lack of geodesic information. In view of this, we present Voxel-Mesh Network (VMNet), a novel 3D deep architecture that operates on the voxel and mesh representations leveraging both the Euclidean and geodesic information. Intuitively, the Euclidean information extracted from voxels can offer contextual cues representing interactions between nearby objects, while the geodesic information extracted from meshes can help separate objects that are spatially close but have disconnected surfaces. To incorporate such information from the two domains, we design an intra-domain attentive module for effective feature aggregation and an inter-domain attentive module for adaptive feature fusion. Experimental results validate the effectiveness of VMNet: specifically, on the challenging ScanNet dataset for large-scale segmentation of indoor scenes, it outperforms the state-of-the-art SparseConvNet and MinkowskiNet (74.6% vs 72.5% and 73.6% in mIoU) with a simpler network structure (17M vs 30M and 38M parameters).

Scenarios of potential vegetation distribution in the different gradient zones of Qinghai-Tibet Plateau under future climate change.

The spatial distribution of potential vegetation types in Qinghai-Tibet Plateau presents a significant vertical zonation. Explicating the vertical differences of potential vegetation distribution under future climate change in Qinghai-Tibet Plateau is an important issue for understanding the response of terrestrial ecosystem to climate change. Based on the observed climate data in 1981-2010 (T0), the scenario data of RCP 2.6, RCP 4.5 and RCP 8.5 released by CMIP5 in 2011-2040 (T1), 2041-2070 (T2) and 2071-2100 (T3), and the digital elevation model (DEM) data, the Holdridge life zone (HLZ) model has been improved to simulate the scenarios of potential vegetation distribution in the different gradient zones of Qinghai-Tibet plateau. The shift model of mean center has been improved to calculate the shift direction and distance of mean center in the potential vegetation types. The ecological diversity index was introduced to compute the ecological diversity change of potential vegetation. The simulated results show that there are 17 potential vegetation types in Qinghai-Tibet Plateau. Wet tundra, high-cold moist forest and nival are the major potential vegetation types and cover 56.26% of the total area of Qinghai-Tibet Plateau. Under the three scenarios, the nival would have the largest decreased area that would be decreased by 3.340 × 104 km2 per decade, and the high-cold wet forest would have the greatest increased area that would be increased by 3.340 × 104 km2 on average per decade from T0 to T3. The potential vegetation types distributed in the alpine zone would show the fastest change ratio (11.32% per decade) and that in low mountain and other zone would show the slowest change ratio (7.54% per decade) on average. The ecological diversity and patch connectivity of potential vegetation would be decreased by 0.108% and 0.290% per decade on average from T0 to T3. In general, the potential vegetation types distributed in the high elevation area generally have a higher sensitivity to climate change in Qinghai-Tibet plateau in the future.