China University of Mining and Technology

The advantageous characteristics of topological photonic crystals facilitate the directional manipulation of waveguides. In this study, we propose a topological photonic crystal that breaks C4 symmetry through rotation, resulting in a symmetric gradient of topological edge state frequencies in both vertical and horizontal directions, thereby enabling precise control over the direction of the edge states. We developed two types of three-channel composite devices informed by our analysis of the transmission characteristics of photonic crystal arrays. These application were experimentally demonstrated in this study. We also construct an eight-path optical device in which topological edge states appear in succession with decreasing wavelengths. These regular transmission waveguides offer new opportunities for device design and the realization of multifunctional effects.

Interfacial solar evaporation is considered as an emerging sustainable solar water technology, capable of capturing solar energy and localizing the generated heat for fast evaporation. Over the past decade, it has drawn significant attention in the design and optimization of materials, structures, and devices, to achieve higher energy conversion efficiency. However, practical applications are limited due to complex designs, high costs, and difficulties in large‐scale implementation. In this perspective, it is focused on the low‐cost recyclable waste utilized for interfacial solar evaporation, and the recent progress in these materials, structures, and devices. In addition, unsolved scientific and technical challenges are also discussed, and provide a forward‐looking perspective, with the aim of continuously promoting the rapid development and application of cost‐effective recyclable waste in interfacial solar evaporation technology, thereby alleviating energy and environmental issues.

Existing research rarely considers the effects of rough fracture seepage on the progressive evolution processes of each physical field, and it primarily focuses on two-dimensional conditions. This study proposes a method to couple the Forchheimer equation with the Reynolds equation with time-varying apertures. The nonlinear flow of three-dimensional fractures under dissolution conditions is achieved. Then, the modified Reynolds equation under steady-state conditions is compared to the flow field governed by the Reynolds equation, and the validity of the modified Reynolds equation after coupling with the Forchheimer equation is verified. The results indicated that the maximum velocity of the flow field controlled by the modified Reynolds equation is slightly lower than that of the flow field controlled by the Reynolds equation, although the overall distribution trends are consistent. Under the control of the modified Reynolds equation, the pressure gradient of the flow field exhibits nonlinearity for the volumetric flow rate. When the fracture is rougher, the nonlinear coefficient increases, enhancing the nonlinearity between the pressure gradient and the volumetric flow. Therefore, the modified Reynolds equation can better represent the nonlinear seepage characteristics of fluids within rough rock fractures. The accuracy of the coupled model regarding the concentration field distribution within the three-dimensional parallel plate fracture and the evolution of the one-dimensional fracture inlet opening is verified using COMSOL multi-physical field coupling software. The theoretical analysis results closely align with numerical analysis, indicating that the model can effectively represent the concentration field distribution and aperture evolution. The research presented in this study can be a predictive method for the dissolution evolution of dam bedrock cracks.

The deterioration of coal strength caused by geological conditions of high gas in deep mines and disturbance from mining operations is one of the elements that influence the incidence of dynamic disasters like gas outbursts and rock bursts. To study how gas pressure and cyclic loads interact to determine the mechanisms and phenomena of coal dynamics, the split Hopkinson pressure bar apparatus was used to perform cyclic impact test on coal samples to investigate the mechanical behavior of gas-bearing coal samples under cyclic dynamic load and gas pressures. The findings indicated that there are three stages in the stress–strain evolution of gas-bearing coal: linear elastic stage, plastic stage, and post-peak stress attenuation. As cycle time grows, the peak stress and attenuation stress of the coal samples decrease, while the maximum and peak strains exhibit a general increasing trend. Under the impact of dynamic load, the macroscopic damage form of the coal sample is mainly a macroscopic crack, and the microscopic examination revealed that the coal samples interior crystal was primarily a trans-granular fracture. By considering dynamic load, gas pressure, and number of cycles, the test results can be more accurately verified by the mechanical damage constitutive model. Finally, based on cyclic dynamic load and gas pressure, the proposed fatigue prediction model of gas-bearing coal can better anticipate coal samples dynamic load-bearing capability.

Overbreak and underbreak are key challenges encountered in drilling and blasting, significantly affecting engineering quality and operational safety. This study addresses the problem of overbreak and underbreak in the Jianshan Underground Mine in Panzhihua. The Riede–Hiermaie–Thoma (RHT) constitutive parameters are determined based on the rock properties on-site and are modified using computed tomography (CT) results from single borehole blasting experiments. The dynamic analysis code is implemented using finite element analysis (Ls-dyna). First, employing the response surface methodology (RSM) experimental method, the influence of single and interactive factors, such as borehole spacing S, smooth blasting layer thickness B, and charge decoupling coefficient Φ, on the surrounding forming effect is analyzed through 2D simulation. The reliability of these results is verified through 3D simulation. The research results indicated that, based on multiple-factor analysis, the optimal contour blasting effect can be achieved for the on-site conditions with a hole spacing of 0.6 m, a smooth blasting layer thickness of 0.7 m, and a charge decoupling coefficient of 1.3. Finally, based on the point cloud distribution obtained from 3D laser scanning, a quantitative analysis method is proposed to characterize the flatness of the surrounding formation. The optimized scheme exhibits a 28% improvement in wall flatness compared to the original scheme, and this method serves as a critical reference for evaluating the effectiveness of intelligent mine construction.

Safety risks management is a critical part during the subway construction. However, conventional methods for risk identification heavily rely on experience from experts and fail to effectively identify the relationship between risk factors and events embedded in accident texts, which fail to provide substantial guidance for subway safety risks management. With a dataset comprising 562 occurrences of subway construction accidents, this study devised a domain-specific entity recognition model for identifying safety hazards during the subway construction. The model was constructed by a Bidirectional Long Short-Term Memory Network with Conditional Random Fields (BiLSTM-CRF). Additionally, a domain-specific entity causal relation extraction model employing Convolutional Neural Networks (CNN) was also developed in thsi model. The constructed models automatically extract safety risk factors, safety events, and their causal relationships from the texts about subway accidents. The precision, recall, and F1 scores of Metro Construction Safety Risk Named Entity Recognition Model (MCSR-NER-Model) all exceeded 77%. Its performance in the specialized domain named entity recognition (NER) with a limited volume of textual data is satisfactory. The Metro Construction Safety Risk Domain Entity Causal Relationship Extraction Model (MCSR-CE-Model) achieved an impressive accuracy, recall, and F1 score of 98.96%, exhibiting excellent performance. Moreover, the extracted entities were normalized and domain dictionary was developed. Based on the processed entities and relationships processed by the domain dictionary, 533 domain entity causal relation triplets were obtained, facilitating the establishment of the directed and unweighted complex network and case database about the risks of subway construction. This research successfully converted accident texts into a causal chain structure of “safety risk factors to risk events,” providing detailed categorization of safety risks and events. Concurrently, it revealed the interrelationships and historical statistical patterns among various safety risk factors and categories of risk events through the complex safety risks network. The construction of the database facilitated project managers in conducting management decisions about safety risks.

The utilization of measurement while drilling (MWD) technology for investigating the geological information of strata, to guide the support design in coal mine roadways, is increasingly emerging as a prevailing trend. However, the distortion of drilling parameters caused by the buckling of drill rod significantly impedes the accuracy of MWD technology. Therefore, this study established an analytical model of sinusoidal buckling for restricted slender drill rod, analyzed the change law of contact friction under the coupling effect of axial loads and drill rod length, and revealed the effect of buckling on distortion characteristics of drilling parameters. Finally, a method for correcting drilling parameters in applications of MWD technology was proposed. The research indicates that during the application of MWD technology at drilling depths between 3.0 and 10.0 m, sinusoidal buckling occurs in the drill rod with orders ranging from 2nd to 5th. Moreover, within this range, thrust ranges between 1.9 and 15.6 kN can be expressed by the boundary equation: 0.27Rc-3.73 ≤ F ≤ 0.37Rc-2.96. Within this depth range for MWD technology application, contact friction ranging from 0.1 to 0.6 kN are observed. The loss distribution ranges are notably 0.5 kN ~ 3.5 kN, 0.5 N∙m ~ 4.5 N∙m, and 150 W ~ 750 W for thrust, torque, and power, respectively. The losses of drilling parameters can be categorized into three distinct zones, and the boundaries’ equations defining each loss zone are delineated. The buckling model in this study is mainly aimed at the drill rods of anchor holes construction in coal mines. Such drill rods and boreholes are much simpler than the drill string and wellbore in oil and gas drilling, which leads to the lower accuracy of the buckling model in this paper in the application of large-diameter drill pipes such as oil and gas drilling. This study has important value for reducing the distortion of drilling parameters and improving the accuracy of MWD technology.

The mudstone-clay composite roof roadway exhibits distinct transversely isotropic characteristics, rendering the prediction of uncoordinated deformation in surrounding rock complex and challenging. Based on transversely isotropic theory, the deformation parameters of mudstone-clay composite in different directions are calculated by true triaxial experiment, and the elastic modulus is determined as the key parameter affecting the uncoordinated deformation of composite roof roadway. The stress and strain expression of roadway surrounding rock is theoretically deduced, and the utilization of ultra-high strength bolts is proposed to control the uncoordinated roadway deformation. The results indicate significant variations in the elastic modulus of the mudstone-clay assemblage in both horizontal and vertical directions, with Poisson’s ratio showing a narrow range of variation. The composite with saturated clay exhibits reduced deformation resistance and more pronounced transverse isotropy compared to the composite with dry clay. The stress concentration is highest near the inflection point of the roadway. The roadway ribs experience vertical stress increase and horizontal stress decrease, while the roof and floor strata mainly undergo vertical stress decrease and horizontal stress increase. The strain in roadway surrounding rock mainly shows vertical strain, especially with the roadway roof exhibiting the highest vertical strain peak and the largest influence range. The vertical strain of roadway surrounding rock can be significantly reduced by increasing the value of its vertical elastic modulus E2, if it is less than 0.15GPa. However, value higher than this has little effect on the strain. According to the field observation, the utilization of ultra-high strength bolt support (E2 > 0.15GPa) in comparison to Q235 threaded steel resin bolt support (E2 < 0.15GPa) demonstrates a significant reduction in roadway uncoordinated deformation, thereby validating the accuracy of theoretical research.

Respirable crystalline silica (RCS) exposure is closely associated with the development of silicosis, underscoring the critical need for the accurate identification of RCS in workplace dust. Occupational health standards currently...

Multi-view Clustering (MVC) has gained significant attention in recent years due to its ability to explore consensus information from multiple perspectives. However, traditional MVC methods face two major challenges: (1) how to alleviate the representation degeneration caused by the process of achieving multi-view consensus information, and (2) how to learn discriminative representations with clustering-friendly structures. Most existing MVC methods overlook the importance of inter-cluster separability. To address these issues, we propose a novel Contrastive Learning-based Dual Contrast Mechanism Deep Multi-view Clustering Network. Specifically, we first introduce view-specific autoencoders to extract latent features for each individual view. Then, we obtain consensus information across views through global feature fusion, measuring the pairwise representation discrepancy by maximizing the consistency between the view-specific representations and global feature representations. Subsequently, we design an adaptive weighted mechanism that can automatically enhance the useful views in feature fusion while suppressing unreliable views, effectively mitigating the representation degeneration issue. Furthermore, within the Contrastive Learning framework, we introduce a Dynamic Cluster Diffusion (DC) module that maximizes the distance between different clusters, thus enhancing the separability of the clusters and obtaining a clustering-friendly discriminative representation. Extensive experiments on multiple datasets demonstrate that our method not only achieves state-of-the-art clustering performance but also produces clustering structures with better separability.

The conventional sensorless control of permanent magnet synchronous motor (PMSM) based on the sliding mode observer (SMO) and the quadrature phase-locked loop (QPLL) is widely used. A method using the finite-position-set phase-locked loop (FPS-PLL) to replace the QPLL has been proposed due to its good dynamic response without the need for parameter adjustment. However, the anti-harmonic capacity of the FPS-PLL is poor, which results in harmonic effects on the estimated rotor position. In this article, the estimated error caused by the FPS-PLL is theoretically analyzed and a second-order generalized integrator (SOGI) based FPS-PLL is studied. In addition, the chattering problem present in the conventional first-order SMO is improved. The effectiveness of this method is validated through experimental results.

The difficult caving of the hard roof during the horizontal slicing fully mechanized top coal caving mining in steep thick coal seams can easily lead to major safety accidents such as gas explosion. To ensure timely and sufficient caving of the roof, this article puts forward the hydraulic fracturing control method of the hard roof during horizontal slicing fully mechanized top coal caving mining in the steep thick coal seam on the basis of analyzing the disaster mechanism of gas explosion accidents caused by hard roof. The pulse hydraulic fracturing technology is used to weaken the roof and top coal, while the directional hydraulic fracturing technology is used to cut off the connection between the roof directly above the goaf and the lower strata, so as to accelerate the roof cave. Compared with before hydraulic fracturing, after hydraulic fracturing, the volume of the goaf cavity can be reduced by about 91%. In addition, the parameters of the roof caving area are also provided. This method has been successfully applied in coal mine site. After the hydraulic fracturing area enters the goaf, the goaf roof caved behind the tail beam of the hydraulic support, and the caving gangue basically fills the goaf.

Sealing technology is critical for the reliability and efficiency of mechanical systems, especially in rotating shaft applications. Traditional ferrofluid (FF) seals, while effective in narrow gaps (0.1–0.3 mm), face significant limitations in maintaining effective sealing under large gap conditions (more than 0.3 mm). To address this challenge, a magnetorheological fluid (MRF) seal optimized for high-speed dynamic applications was proposed. Firstly, a sealing structure was designed, and the rheological properties of MRF were characterized. Then, theoretical models for both FF and MRF seals were derived to analyze their operating principles and performance differences. A custom test bench was constructed to evaluate static sealing performance at 0.1 mm and 0.4 mm gaps and dynamic sealing performance at shear velocities of 0.2, 0.4, 0.6, 0.8, and 1.0 m/s. Experimental results demonstrated that MRF seals achieve higher pressure differentials compared to FF seals, particularly in large gap scenarios. These findings suggest that MRF seals offer a promising alternative for advanced sealing applications in mechanical systems.

Developing highly efficient and selective catalysts for chemical recycling and upcycling of plastic waste is essential for establishing a sustainable plastics economy and reducing environmental impact. Here, we report a novel tetranuclear titanium catalyst that enables highly efficient transesterification reactions of esters and polyesters. Detailed experimental and computational studies have revealed that a bi‐titanium framework facilitates a dual activation mechanism, activating both alcohol and ester simultaneously, thereby significantly enhancing the transesterification process. This catalyst demonstrated exceptionally high activity in the methanolysis of poly(ethylene terephthalate) (PET) with an activity up to 1.9 × 10⁷ gPET molTi⁻¹ h⁻¹ at 0.005 mol% catalyst loading, producing polymerizable dimethyl ester and glycol monomers. Additionally, it effectively catalyzed the re‐polymerization of the recovered monomers, yielding the original polyester with high molecular weight and thereby achieving an ideal circular economy for commodity polyesters. Furthermore, this catalyst can also be utilized for the efficient upgrading of PET waste via transesterification with 1,4‐butanediol, polybutylene adipate, and poly(tetramethyene ether glycol), yielding engineering plastic, biodegradable polyester, and thermoplastic elastomer, respectively.

Conventional electrolytes in lithium metal batteries (LMBs) suffer from irreversible interfacial degradation at elevated temperatures and sluggish Li⁺ desolvation/transport kinetics under cryogenic conditions. Herein, we present an innovative semi‐solvated hexafluoroisopropyl methyl ether (HFME) diluent in localized high‐concentration electrolytes (LHCEs) that strategically addresses these limitations. Li⁺ hopping networks within the electrolyte can be preserved even at low temperatures due to the coordination of lithiophilic groups in HFME molecules with Li⁺. Simultaneously, lithiophobic group induced spatial confinement effects promote the formation of anion–cation aggregates (AGGs), significantly optimizing Li⁺ desolvation kinetics and boosting the formation of inorganic‐dominated solid electrolyte interphase (SEI) with exceptional thermal stability. Li||LiFePO4 (LFP) cell with the diluent‐coordinated LHCEs (DCL) can deliver 125.4 mA h g⁻¹ initial capacity at −20 °C with 92.2% retention after 150 cycles. Under elevated temperatures (65 °C), the DCL‐based Li||LFP cell can maintain the capacity retention of 91.3% over 60 cycles. The Li||NCM811 pouch cell (10 cm × 6.5 cm, capacity: 1000 mA h) based on the DCL exhibits outstanding cycling stability, retaining 91.6% of its initial capacity after 75 cycles. This work pioneers a solvent chemistry paradigm through spatially modulated solvation structures, establishing fundamental design principles for electrolyte for wide‐temperature‐range LMBs.

Thick‐film (>300 nm) organic solar cells (OSCs) have garnered intensifying attention due to their compatibility with commercial roll‐to‐roll printing technology for the large‐scale continuous fabrication process. However, due to the uncontrollable donor/acceptor (D/A) arrangement in thick‐film condition, the restricted exciton splitting and severe carrier traps significantly impede the photovoltaic performance and operability. Herein, combined with layer‐by‐layer deposition technology, a twisted 3D star‐shaped trimer (BTT‐Out) is synthesized to develop a trimer‐induced pre‐swelling (TIP) strategy, where the BTT‐Out is incorporated into the buried D18 donor layer to enable the fabrication of thick‐film OSCs. The integrated approach characterizations reveal that the exceptional configuration and spontaneous self‐organization behavior of BTT‐Out trimer could pre‐swell the D18 network to facilitate the acceptor's infiltration and accelerate the formation of D/A interfaces. This enhancement triggers the elevated polarons formation with amplified hole‐transfer kinetics, which is essential for the augmented exciton splitting efficiency. Furthermore, the regulated swelling process can initiate the favorable self‐assembly of L8‐BO acceptors, which would ameliorate carrier transport channels and mitigate carrier traps. As a result, the TIP‐modified thin‐film OSC devices achieve the champion performance of 20.3% (thin‐film) and 18.8% (thick‐film) with upgraded stability, among one of the highest performances reported of thick‐film OSCs.

Carbon monoxide is a primary pollutant in energy-rich regions. Here we use a space-based mass-conserving framework based on observed carbon monoxide and formaldehyde columns to quantify carbon monoxide emissions over the energy-driven province of Shanxi, China. Annualized total emissions are seven times higher on average compared with some existing datasets, partly due to the fractional increase in low-emitting area’s energy consumption, resulting in a spatial mis-alignment. This induces a net 7% increase in CO2 emissions. Substantial forcings include atmospheric lifetime (10th and 90th percentile of carbon monoxide and formaldehyde are [1.0, 5.7] days and [0.2, 2.3] hours) and transport. Carbon monoxide decreased year-by-year, although only obvious at the two/three peak emission months. Cross-border transport is important during the same months, including sources from central Shaanxi and western Hebei. Carbon monoxide to nitrogen oxides ratios show obvious differences and give source attribution over industrial areas (including cement, power, iron/steel, and coke).

This article proposes a Series and Parallel synchronized switching harvesting on capacitor (S&P‐SSHC) rectifier to efficiently extract energy from piezoelectric transducer (PZT). By combining the Series synchronized switching harvesting mode (S‐mode) together with Parallel synchronized switching harvesting mode (P‐mode), the S&P‐SSHC rectifier can achieve an excellent energy harvesting efficiency over a wide range of vibration excitation under a fixed low output voltage. Moreover, the synchronized switch harvesting on capacitor technology utilized in S‐mode with the same flipping caps as using in P‐mode maintains a high‐voltage flipping efficiency (), while avoiding the addition of extra components. A switched‐capacitor (SC) DC‐DC converter composed of the reconfigured flipping caps aims to enhance the input independence ability and its limited voltage‐conversion‐ratio (VCR) will not affect harvesting efficiency due to the supplementation of S‐mode. The proposed rectifier circuit is designed and simulated in a 0.18‐m BCD process. The performance measured by simulation demonstrate that the proposed S&P‐SSHC rectifier can maintain a maximum output power improving rate over full‐bridge rectifier (FOM) of > 6.01 with an open‐circuit peak‐to‐peak voltage of PZT () range from 0.5 to 10 V and a fixed loading voltage of 1.5 V.

The monitoring of body temperature is critical for assessing the health conditions of a critically ill patient. Flexible temperature sensors provide direct contact with human skin, ensuring stable and continuous monitoring of a person’s body temperature. In this study, an affordable and readily available polyvinylidene fluoride (PVDF) was used as the polymer matrix for fabricating a wearable temperature sensor. Through a simple solution mixing process, both conductive carbon black (CB) and ionic liquid were uniformly dispersed in the flexible PVDF composite for enhancing its conductivity and stability. The influence of CB addition amounts was investigated with respect to surface morphology, microstructure, and properties. The results showed that the composite with 6% CB addition had the highest sensitivity of 3.07%/°C, with a minimum detectable temperature difference of 1°C and short response/recovery times of 6.66 s/15.63 s at ΔT = 10°C. Additionally, the response/recovery curves of this device demonstrated good cycle stability. Furthermore, the sensor retained its superior performance even after extended operational periods, confirming the long-term stability and reliability of this thin-film sensor. The sensor shows great promise for physiological signal detection and holds substantial potential for applications in wearable electronics. This work offers a new possibility for the low-cost, large-scale fabrication of flexible temperature sensors in the future.

We theoretically investigate the electric field-tuning plasmons and plasmon–phonon couplings of two-dimensional (2D) transition metal dichalcogenides (TMDs), such as monolayer MoS 2, under the consideration of spin–orbit coupling. It is revealed that the frequencies of plasmons and coupled plasmon-phonon modes originating from electron–electron and electron–phonon interactions can be effectively changed by using applied driving electric fields. Notably, these frequencies exhibit a decreasing trend with an increasing electric field. Moreover, the weak angular dependence of these modes suggests that the driving electric field does not induce significant anisotropy in the plasmon modes. The outcomes of this work demonstrate that the plasmon and coupled plasmon–phonon modes can be tuned not only by manipulating the electron density via the application of a gate voltage but also by tuning the applied driving electric field. These findings hold relevance for facilitating the application of 2D TMDs in optoelectronic devices.