Search

The expansion of a thick-walled hollow cylinder in soil is of non-self-similar nature that the stress/deformation paths are not the same for different soil material points. As a result, this problem cannot be solved by the common self-similar-based similarity techniques. This paper proposes a novel, exact solution for rigorous drained expansion analysis of a hollow cylinder of critical state soils. Considering stress-dependent elastic moduli of soils, new analytical stress and displacement solutions for the non-self-similar problem are developed taking the small strain assumption in the elastic zone. In the plastic zone, the cavity expansion response is formulated into a set of first-order partial differential equations (PDEs) with the combination use of Eulerian and Lagrangian descriptions, and a novel solution algorithm is developed to efficiently solve this complex boundary value problem. The solution is presented in a general form and thus can be useful for a wide range of soils. With the new solution, the non-self-similar nature induced by the finite outer boundary is clearly demonstrated and highlighted, which is found to be greatly different to the behaviour of cavity expansion in infinite soil mass. The present solution may serve as a benchmark for verifying the performance of advanced numerical techniques with critical state soil models and be used to capture the finite boundary effect for pressuremeter tests in small-sized calibration chambers.

Gallium arsenide (GaAs) semiconductor wires have emerged as potent candidates for nonlinear optical devices, necessitating bandgap engineering for an expanded operational wavelength range. We report the successful growth of strain-mediated GaAs microwires (MWs) with an average diameter of 1.1 μm. The axial tensile strain in these wires, as measured by X-ray diffraction and Raman scattering, ranges from 1.61 % to 1.95 % and from 1.44 % to 2.03 %, respectively. This strain condition significantly reduces the bandgap of GaAs MWs compared to bulk GaAs, enabling a response wavelength extension up to 1.1 μm. Open aperture Z-scan measurements reveal a nonlinear absorption coefficient of −15.9 cm/MW and a third-order magnetic susceptibility of −2.8 × 10−8esu at 800 nm for these MWs. I-scan measurements further show that the GaAs saturable absorber has a modulation depth of 7.9 % and a nonsaturation loss of 3.3 % at 1050 nm. In laser applications, GaAs MWs have been effectively used as saturable absorbers for achieving Q-switched and dual-wavelength synchronous mode-locking operations in Yb-bulk lasers. These results not only offer new insights into the use of large diameter semiconductor wires but also expand the potential for applications requiring bandgap tuning.

Red mud is a solid waste in aluminum industry and has been proven to be an efficient alternative to NOxselective catalytic reduction (SCR) catalysts. Acid washing treatment to red mud can improve its alkalinity and surface properties, and increase the conversion rate of NOx. In this paper, Cu, Ce, and Cu/Ce was supported on acid washed red mud and NOxcatalytic conversion performance on metal modified red mud catalysts was studied. The research results indicate that Cu+and Cu2+in the Cu supported catalyst effectively promote NO conversion rate of red mud in low-temperature (200–300 °C) flue gas, reaching a maximum of 90.7%; Ce3+and Ce4+in Ce supported catalysts effectively promote the NO conversion rate of red mud in flue gas at 200–400 °C, reaching a maximum of 94.0%; Cu/Ce supporting exhibits better NO conversion rate than single metal supported catalysts at low-temperatures, the optimal Cu:Ce ratio for supporting is 1:1; and also exhibits better NO conversion rate than Cu supported catalysts at high-temperature (300–400 °C), reaching a maximum of 95.5%. The reason may be that under the synergistic effect of Cu/Ce, ACRM-Cu1Ce1 has stronger low-temperature redox ability, higher weak acidic peaks, higher average oxidation state of Fe ions, and higher Cu+content.

The tribological behavior of carboxylic acids, especially oleic acid, in boundary lubrication conditions is a subject of interest. This study presents the results of four-ball tribological tests conducted under varying contact pressures and sliding speeds. The findings reveal a critical turning speed within a confined zone, which causes a significant change in the frictional performances of oleic acid, leading to the formation of an ultralow wear tribofilm. This tribofilm, predominantly composed of oxyhydrogen compounds and hydrocarbons with more than five carbon atoms, is generated by the molecular action of oleic acid. Reactive nonequilibrium molecular dynamics simulations demonstrate that the shear speed-dependent decomposition modes of oleic acid and the transformation of the lubrication slip interface are the fundamental processes underlying the formation of this ultralow-wear boundary tribofilm.

Traffic prediction is crucial to the intelligent transportation system. However, accurate traffic prediction still faces challenges. It is difficult to extract dynamic spatial–temporal correlations of traffic flow and capture the specific traffic pattern for each sub-region. In this paper, a temporal attention recurrent graph convolutional neural network (TARGCN) is proposed to address these issues. The proposed TARGCN model fuses a node-embedded graph convolutional (Emb-GCN) layer, a gated recurrent unit (GRU) layer, and a temporal attention (TA) layer into a framework to exploit both dynamic spatial correlations between traffic nodes and temporal dependencies between time slices. In the Emb-GCN layer, node embedding matrix and node parameter learning techniques are employed to extract spatial correlations between traffic nodes at a fine-grained level and learn the specific traffic pattern for each node. Following this, a series of gated recurrent units are stacked as a GRU layer to capture spatial and temporal features from the traffic flow of adjacent nodes in the past few time slices simultaneously. Furthermore, an attention layer is applied in the temporal dimension to extend the receptive field of GRU. The combination of the Emb-GCN, GRU, and the TA layer facilitates the proposed framework exploiting not only the spatial–temporal dependencies but also the degree of interconnectedness between traffic nodes, which benefits the prediction a lot. Experiments on public traffic datasets PEMSD4 and PEMSD8 demonstrate the effectiveness of the proposed method. Compared with state-of-the-art baselines, it achieves 4.62% and 5.78% on PEMS03, 3.08% and 0.37% on PEMSD4, and 5.08% and 0.28% on PEMSD8 superiority on average. Especially for long-term prediction, prediction results for the 60-min interval show the proposed method presents a more notable advantage over compared benchmarks. The implementation on Pytorch is publicly available at https://github.com/csust-sonie/TARGCN.

Plant roots integrate environmental signals with development using exquisite spatiotemporal control. This is apparent in the deposition of suberin, an apoplastic diffusion barrier, which regulates flow of water, solutes and gases, and is environmentally plastic. Suberin is considered a hallmark of endodermal differentiation but is absent in the tomato endodermis. Instead, suberin is present in the exodermis, a cell type that is absent in the model organism Arabidopsis thaliana. Here we demonstrate that the suberin regulatory network has the same parts driving suberin production in the tomato exodermis and the Arabidopsisendodermis. Despite this co-option of network components, the network has undergone rewiring to drive distinct spatial expression and with distinct contributions of specific genes. Functional genetic analyses of the tomato MYB92 transcription factor and ASFT enzyme demonstrate the importance of exodermal suberin for a plant water-deficit response and that the exodermal barrier serves an equivalent function to that of the endodermis and can act in its place.

The microstructure evolution and mechanical properties of a Fe–0.12C–0.2Si–1.6Mn–0.3Cr–0.0025B (wt.%) steel with different initial microstructures, i.e., hot rolled (HR) and cold rolled–annealed (CRA), were studied through optical microscopy, scanning electron microscopy, electron channeling contrast imaging, microhardness and room temperature uniaxial tensile tests. After water quenching from 930 °C to room temperature, a fully martensitic microstructure was obtained in both as-quenched HR and CRA specimens, which shows a microhardness of 480 ± 5 HV, and no significant difference in microstructure and microhardness was observed. Tensile test results show that the product of tensile strength and total elongation (UTS × TE) of the as-quenched HR specimen, i.e., 24.1 GPa%, is higher than that of the as-quenched CRA specimen, i.e., 18.9 GPa%. While, after being tempered at 300 °C, the martensitic microstructures and mechanical properties of the two as-quenched specimens change significantly due to the synergy role of the matrix phase softening and the precipitation strengthening. Concerning the maximum UTS × TE, it is 18.9 GPa% obtained in the as-quenched CRA one, while that is 24.4 GPa% obtained in the HR specimen after tempered at 300 °C for 5 min.

Complex quadratically constrained quadratic programs (QCQPs) with underlying acyclic graph structures have special interests in some important practical applications. In this paper, we propose a new second-order cone relaxation for complex QCQPs, and prove some sufficient conditions under which the proposed relaxation is tight. Then, based on the proposed second-order cone relaxation, a branch-and-bound algorithm is developed. The main feature of the proposed branch-and-bound algorithm is that some complex variables are selected with their bounds on modules or phase angles partitioned in the branching procedure. Numerical results indicate that the proposed branch-and-bound algorithm runs faster than Baron on randomly generated test instances, and is also effective in solving some publicly available test instances of optimal power flow problems.

A high-sensitivity fiber optic strain sensor based on chirped fiber Bragg grating-Fabry Perot interferometer (CFBG-FPI) and vernier effect is proposed and has been demonstrated to have a strain sensitivity of −123.8 pm/μϵ. With femtosecond laser direct writing technology, two pairs of CFBGs with the same reflectivity, length, chirp rate and center wavelength are inscribed inside the single-mode fiber core, forming two separated CFBG-FPIs. Combined with the vernier effect principle, the interferometric cavity lengths of the two CFBG-FPIs were designed at about 1.7 mm and 1.68 mm as the reference arm and sensing arm, respectively, to form the vernier effect system, and the spacing between the reference arm and the sensing arm was 1 m. Experimental results show that in this vernier effect system, the strain sensitivity gain due to the vernier effect reaches a staggering 91-fold relative to a single CFBG-FPI, resulting in an ultra-high sensitivity of −123.8 pm/μϵ. In addition to being compact and convenient to manufacture, the sensor exhibits a low temperature cross-sensitivity down to −0.14 μϵ/°C. The many advantages make this sensor extremely promising for high-precision strain measurement applications.

New energy microgrid is one of the development trends of the future power grid. As there are wind turbines and other new energy equipment in the microgrid, its output is easily affected by unstable weather factors. Moreover, the complexity of dispatching caused by the storage battery in the microgrid and the non-linear factors of the diesel generator have brought great challenges to the economic dispatching of the microgrid. To tackle these problems, this paper establishes the expected value model of microgrid economic dispatching considering the uncertainty of wind power generation and the factors such as battery and diesel generator and proves that this expected value model is convex. On this basis, the piecewise linearization method is proposed to find the global optimal solution of the economic dispatch. Finally, a representative microgrid is optimized to verify the effectiveness of expected value model.

An enantioselective palladium-catalyzed C–H arylation of functionalized pyrazoles/triazoles/imidazoles is developed, affording a variety of axially chiral ortho-nitro/formyl-substituted heterobiaryls with excellent enantioselectivities and good yields. The method features a deuterated P-chiral phosphorus ligand CD3-AntPhos, a broad substrate scope of functionalized heterobiaryls, mild reaction conditions, and low palladium loadings.

ABSTRACTThe compressive strength of pellets is of great significance for the evaluation of pellets quality indexes. In this paper, the chemical composition, mineral phase composition and microstructure of pellets were analyzed by ICPAES, XRD, OM and SEM-EDS through oxidation roasting and gas-based reduction experiments. The effect mechanism of thermal regulation on the compressive strength and reduction performance of pellets was explained by the micro-indicators such as porosity, Vickers hardness and morphological structure of pellets. The results showed that with the increase of the roasting temperature and the extension of the roasting time, the internal porosity of the oxidized pellets was reduced, while the compressive strength of the pellets was continuously improved, and the roasting temperature had a greater influence on the compressive strength. However, the increase in porosity of the reduced pellets weakened the intergranular bonding between the particles, which led to a reduction in compressive strength.

The compressive strength of pellets is of great significance for the evaluation of pellets quality indexes. In this paper, the chemical composition, mineral phase composition and microstructure of pellets were analyzed by ICPAES, XRD, OM and SEM-EDS through oxidation roasting and gas-based reduction experiments. The effect mechanism of thermal regulation on the compressive strength and reduction performance of pellets was explained by the micro-indicators such as porosity, Vickers hardness and morphological structure of pellets. The results showed that with the increase of the roasting temperature and the extension of the roasting time, the internal porosity of the oxidized pellets was reduced, while the compressive strength of the pellets was continuously improved, and the roasting temperature had a greater influence on the compressive strength. However, the increase in porosity of the reduced pellets weakened the intergranular bonding between the particles, which led to a reduction in compressive strength.

Excellent thermal neutron absorption performance of boron expands the potential use of boron rich slag to prepare epoxy resin matrix nuclear shielding composites. However, shielding attenuation behaviors and mechanism of the composites against gamma rays are unclear. Based on the radiation protection theory, Phy-X/PSD, XCOM, and 60Co gamma ray source were integrated to obtain the shielding parameters of boron rich slag/epoxy resin composites at 0.015–15 MeV, which include mass attenuation coefficient (μt), linear attenuation coefficient (μ), half value thickness layer (HVL), electron density (Neff), effective atomic number (Zeff), exposure buildup factor (EBF) and exposure absorption buildup factor (EABF).μt, μ, HVL, Neff, Zeff, EBF and EABF are 0.02–7 cm2/g, 0.04–17 cm−1, 0.045–20 cm, 5–14, 3 × 1023–8 × 1023electron/g, 0–2000, and 0–3500. Shielding performance is BS4, BS3, BS3, BS1 in descending order, but worse than ordinary concrete. μand HVLof BS1-BS4 for 60Co gamma ray is 0.095–0.110 cm−1and 6.3–7.2 cm. Shielding mechanism is main interactions for attenuation gamma ray by BS1-BS4 are elements with higher content or higher atomic number via Photoelectric Absorption at low energy range, and elements with higher content via Compton Scattering and Pair Production in Nuclear Field at middle and higher energy range.

Based on the literature study and investigation. this paper explored into the generative context of Kamification of the online sports communication, analyzing the external representation of its behavior, as well as the underlying issues of demand so as to reveal the social influences and propose corresponding strategies. It was held that the gamification media practice of online sports communication originated from the context of being digital, with the logic of being digital through immediacy of behavioral experience, unsoundness of time perception and diversity of evaluation criteria. It reflected the behavior of the user's Nymph body, and the demand of the user's digital identity reconstruction. In view of the negative impact of garnified media practice of online sports communication, such as capitalized production, technology intermediation and human subjectivity, this paper put forward that the integration, innovation and regularity of the sports for all communication in China should be emphasized so as to construct the new pattern of the sports communication in convergence media, to improve the industrial chain of the online sports communication, and to strive to create more high-quality media content products, so as to guide the healthy development of the gamification. [ABSTRACT FROM AUTHOR]

The isothermal steam gasification experiments of a ternary mixture (BTP) containing black liquor char (BLC), causticizing agent (TiO2) and petroleum coke (PC) were carried out at 850 °C based on a thermogravimetric analyzer (TGA) and a horizontal fixed-bed reactor. A co-gasification process of BLC and PC coupled with TiO2direct causticization was explored from the aspect of reaction rate as well as the characteristics of gaseous products and gasification residues (GR). The results show that in comparison to the weighted average (BTPtheo) of the independent gasification of TiO2direct causticized BLC and PC, significant synergistic effects could be aroused during the coupled co-gasification process due to promoting action of mNa2O·nTiO2on gasification of organic carbon. Specifically, the maximum reaction rate of BTP reaches 7.0%/min, which is 2.9 times that of BTPtheo. The content and yield of effective gas components, i.e., H2+CO, in the gas products, as well as its lower heating value (LHV) of BTP are 81.1%, 2059 mL/g, and 9343 kJ/m3, respectively, which is 6.8%, 137.3%, and 5.5% higher than that of BTPtheo. The carbon conversion and energy output ratio of BTP reaches 95.0% and 1.13, respectively, which is increased by 61.6% and 135.4% relative to the theoretical superposition value. In addition, the relative loss of inorganic salts in BTP during the whole thermochemical conversion process is effectively controlled at a lower level of about 9.4%. Since the Na-containing salts in GR of BTP are mainly mNa2O·nTiO2with higher thermal stability, and GR maintains good particle flowability, it is conducive to downstream alkali recovery.

Catalytic degradation of organic contaminants is at the frontier of water treatment due to its selectivity, energy savings, and ability to convert harmful contaminants into harmless or even valuable chemical products for recycling. However, achieving sufficiently high performance in the catalytic removal of organic contaminants for practical application is still extremely challenging. Herein, we report a Pd-decorated TiO2(Pd/TiO2) hierarchical vertical array for fast and efficient catalytic water treatment. Such a forestlike Pd/TiO2vertical array demonstrates the following distinct advantages over conventional planar or bulk catalytic systems: 1) abundant anchoring sites for nanocrystals loading; 2) high sunlight absorption; 3) efficient mass transfer channels for the reactants and products. As a proof of concept, the Pd/TiO2array demonstrated rapid and efficient photo-assisted catalytic reduction of high concentrations of 4-nitrophenol wastewater (2 g/L, ca.14.38 mmol/L) and its feasibility for continuous flow wastewater treatment. The turnover frequency (TOF) value of the Pd/TiO2array was up to 8.00 min−1, which was approximately 4.2 times that of planar Pd/TiO2film with the same area (1.91 min−1). Our strategy of incorporating nanocatalysts with a hierarchical vertical array provides a promising approach to boosting the catalytic performance of catalysts for different chemical reactions.

Improving the coupling efficiency of the optical transceiver module in fiber optic gyroscopes (FOGs) benefits both the working efficiency of the module and the signal-to-noise ratio of the FOG system. In this work, a single-mode fiber (SMF) with an elliptical mode field distribution is proposed as the coupling fiber for the FOG transceiver module. The coupling efficiency of the transceiver module using fibers with different mode field distributions at the endface is analyzed. Two structure schemes of the transceiver module are compared: one focuses the beam directly onto the endface of the fiber, and the other collimates the beam and then converges it. The optimal coupling efficiency can reach above 91.5% when the horizontal and vertical mode field radii of the fiber endface are approximately 4.05 and $3.37 \mu \text{m}$ , respectively. The influence of the axial and angular alignment errors of the pigtail on the coupling efficiency is also investigated. The maximum tolerance of the axial alignment reaches approximately ±40.10 and $\pm 30.08 \mu \text{m}$ for the two structure schemes. The maximum tolerance of the angular alignment reaches approximately ±4.4° and ±5.2° in the horizontal direction, and approximately ±3.5° and ±3.6° in the vertical direction, respectively. These tolerances are favorable for practical applications.

Dry reforming of ethane (DRE) has received significant attention because of its potential to produce chemical raw materials and reduce carbon emissions. Herein, a composition-induced strong metal–support interaction (SMSI) effect over FeNi/Al–Ce–O catalysts is revealed via X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (TPR), and energy dispersive X-ray spectroscopy (EDS) elemental mapping. The introduction of Al into Al–Ce–O supports significantly influences the dispersion of surface active components and improves the catalytic performance for DRE over supported FeNi catalysts due to enhancement of the SMSI effect. The catalytic properties, for example, C2H6and CO2conversion, CO selectivity and yield, and turnover frequencies (TOFs), of supported FeNi catalysts first increase and then decrease with increasing Al content, following the same trend as the theoretical effective surface area (TESA) of the corresponding catalysts. The FeNi/Ce–Al0.5catalyst, with 50% Al content, exhibits the best DRE performance under steady-state conditions at 873 K. As observed by with in situFourier transform infrared spectroscopy (FTIR) analysis, the introduction of Al not only increases the content of surface Ce3+and oxygen vacancies but also promotes the dispersion of surface active components, which further alters the catalytic properties for DRE over supported FeNi catalysts.

Global energy crisis and climate change have caused widespread concern about the development of the biomass energy industry. China has committed to exploring feasible policies to promote the development of the biomass energy industry. To analyze the impact of China’s energy tax subsidy policy (ETS) on the development of densified biomass fuel (DBF) industry, this study constructs a partial equilibrium model of the densified biomass fuel industry sector to quantitatively evaluate and optimize the effect of China’s current ETS policy based on the compilation of input–output table for the biomass energy industry sector in China. The results indicate that 1) under the current policy scenario, the price of DBF in China decreased by 15.05%, the supply increased by 40.75%, and the demand increased by 18.62%, while the price of raw biomass (RB) decreased by 14.75%, the supply increased by 42.44%, and the demand increased by 29.41%, and the revenue of enterprises increased by 20.42%. However, compared to China’s 13th Five-Year Plan national DBF development target, there is still a supply and demand gap of 16,560,549 tons. 2) under the optimized policy scenario premised on accomplishing the Chinese government’s DBF development goals, the price of DBF in China decreased by 6.9%, supply increased by 128.5%, and demand increased by 44.5%, while the price of raw biomass decreased by 7.84%, supply increased by 133.34%, demand increased by 45.71%, and corporate earnings rose by 112.1% but required the government to pay extremely high tax benefits and financial subsidies for this, which is not feasible in actual economic operation. Therefore, to support the sustainable development of the DBF industry, relevant departments should not only set the mandatory total target but also pursue production quality and market construction.

The optimal control, for a class of nonlinear neutral evolution equations involving Riemann–Liouville fractional derivative, is investigated in this paper by using Darbo–Sadovskii fixed point theorem. An example is given in the last section to illustrate the validity of the abstract conclusions.

Due to the complex structure and thermal mismatch of coaxial through silicon via (TSV), cracks easily occur under thermal load, leading to interface delamination or spalling failure. The reliability issue of coaxial TSV is important for its application in three-dimensional packaging, so it is of great significance to predict the crack trend and evaluate the reliability of coaxial TSV. In this paper, an algorithm model with the combination of whale optimization algorithm (WOA) and back propagation (BP) neural network for the reliability prediction of coaxial TSV is proposed. Based on finite element method (FEM), the training and validation datasets of the energy release rates (ERR) of the crack at the critical interface are calculated to construct the deep learning neural network. Six key structure parameters affecting the reliability of coaxial TSV are selected as the input values of the BP neural network. The maximum relative error of whale optimization algorithm optimized back propagation (WOA-BP) neural network model is 0.88%, which is better than the prediction results of the traditional BP and genetic algorithm (GA) optimized BP models. The WOA-BP neural network model was also compared with BP and GA-BP neural network models with four error metric models. It is verified that WOA-BP neural network model has the best prediction performance. The proposed model can be used to achieve improved prediction accuracy for the interface reliability of coaxial TSV under complex structural conditions since it has higher accuracy and stronger robustness.

A new one-pot preparation of 4-tetrazolyl-3,4-dihydroquinazolines has been reported. The Ugi-azide reactions of 2-azidobenzaldehydes, amines, trimethylsilyl azide, and isocyanides produced azide intermediates without separation, which were treated with isocyanides to give 4-tetrazolyl-3,4-dihydroquinazoline derivatives through a sequential Palladium-catalyzed azide-isocyanide cross-coupling/cyclization reaction in moderate to good yields. The biological evaluation demonstrated that compound 6cinhibited breast cancer cells well and displayed broad applications for synthesis and medicinal chemistry.

AbstractThis paper presents rigorous analytical solutions for cavity contraction analysis of a thick-walled cylinder/sphere after an arbitrary magnitude of expansion. Closed-form solutions are given for the distribution of stress and displacement within the cylinder/sphere of soil that is subjected to constant external pressure and monotonically decreasing internal pressure. The soil is modelled as an elastic-perfectly plastic material obeying the Mohr-Coulomb yield criterion and a non-associated flow rule. Large strain effects are taken into account by adopting the logarithmic strain definition in the plastic deformation analysis. The new solutions are validated with published results at first, then parametric studies are carried out. It is shown that the reference stress state (e.g. in-situ, elastic, partially plastic and fully plastic) and the cavity geometry ratio may greatly affect the unloading behaviour, in particular, when the cavity geometry ratio is smaller than a limit value. Finally, three typical applications of the solutions are demonstrated, including (i) design of the thickness of frozen cylinder walls accounting for large deformation effects, (ii) interpretation of laboratory pressuremeter tests with consideration of effect of the constant stress boundary, and (iii) shakedown analysis of a soil cylinder/sphere considering its geometry changes upon cyclic loading and unloading.

The adsorption–diffusion process of methane (CH4) in coal seams directly affects the amount of extractable gas (i.e., the free gas content). To clarify the relationship between the CH4multiscale migration process and complex pore structure characteristics, the adsorption and diffusion characteristics of coal samples with different metamorphic degrees were taken as the research object, subdivided the gas adsorption structure scale, and quantitatively characterized the adsorption capacity of coal under different adsorption modes. Then, combined with the fractal characteristics of the coal adsorption pore complex structure, the evolution law of methane nonsteady-state diffusion was introduced to calculate the effective diffusion coefficient of methane under the unsteady state, elucidated the mathematical quantitative relationship between diffusion characteristics and structure characteristics, and explored the influence mechanism of coal structural parameters on the methane diffusion law. The results verified that the specific surface area was the dominant factor in the case of monolayer adsorption, while the complexity of the microporous structure was the most important factor in the case of microporous filling. Based on the calculation results of the fractal capillary bundle diffusion model, it was found that the specific surface area indirectly affects the diffusion movement by affecting the gas adsorption process, thus playing a leading role in the influence of fractal diffusion capacity of methane in coal. Overall, our research results provide a theoretical reference for the efficient mining of coalbed methane and mine gas disaster prevention.