Many examples have shown that rockfalls can occur in underground coal mines. The presence of rockfalls in the long walls of a steeply dipping coal seam (SDCS) is harmful due to the cumulative damage ...effects of rockfall near active mining faces. Therefore, this study aims to assess rockfall hazards in SDCS mining and propose corresponding protective measures. The steps are as follows: Step 1: The on-site coal wall spalling was investigated. Information such as the shape, size, and location of the detached block was collected. Step 2: The risk indicators Ē and ĒCOR,BE that characterize the cumulative damage effects of rockfall were proposed. Step 3: A small-scale impact test was performed in the laboratory to study the rockfall characteristics, and a sensitivity analysis for the risk indicators under different block diameters, seam inclinations, and longwall floor Schmidt hardness was conducted. Step 4: A risk assessment model for rockfall hazards was established. Rockfall risks can be divided into five degrees based on the distribution of Ē and ĒCOR,BE. Among them, the laws of Ē and ĒCOR,BE were obtained through Step 3. ΔE can be obtained under two scenes, with or without equipment, on the longwall floor. Ed is the critical energy for equipment destruction, which is related to the equipment materials. Step 5: The risk assessment method for rockfall in longwalls of an SDCS is proposed based on evaluating Ē and ĒCOR,BE. Specifically, the risk assessment model was combined with the on-site damaged hydraulic support, and then, the verification of the risk assessment method was accomplished through a comparison of the small-scale impact test in the laboratory and on-site damage measurements. Finally, three protective principles were discussed. This study provides a method for risk assessment and for determining the principles of protective systems in underground steep coal seams.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract In the process of fully mechanized top-coal caving mining, the top-coal is affected by mining-induced stress, and the stress varies along the strike direction of working face, so the ...boundary position of its entering the limit equilibrium state changes accordingly. The determination of the boundary along the strike direction of working face can provide scientific guidance for the stability control of support-surrounding rock in fully mechanized top-coal caving face. Using the research methods of theoretical analysis, physical similarity simulation experiment and numerical simulation experiment, the stress state analysis model of the boundary position of the top-coal limit equilibrium zone under macro-scale conditions was established, the stress state characterization method of the boundary of the top-coal limit equilibrium zone along the strike direction of working face was given, and the quantitative characterization of the boundary of the top-coal limit equilibrium zone along the strike direction of working face was realized by combining with the mining-induced stress path, and the distance relationship between the boundary of the top-coal limit equilibrium zone and the langwall face along the strike direction of working face was revealed. The results show that after critical mining in fully mechanized top-coal caving face, the distance between the boundary of top-coal limit equilibrium zone and the langwall face along the strike direction of working face presents a relationship of increasing from top to bottom. The distance between the top-coal upper boundary and the langwall face was 2.85 m and the distance between the top-coal lower boundary and the langwall face was 5.39 m. The boundary of top-coal limit equilibrium zone along the strike direction of working face was verified by the top-coal elastic–plastic zone boundary and the boundary of the peak position of front abutment pressure in different layers of top-coal. The results show that the quantitative characterization of the top-coal limit equilibrium zone boundary along the strike direction of working face was reasonable. In order to improve mine production efficiency, optimization measures were put forward for hard coal seam and soft coal seam respectively.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
To solve the problem that the macroscopic deformation and failure of coal-rock medium under external loads are easy to be observed while the internal stress transfer mode and path are unclear. Based ...on the discrete element idea, the numerical models for pure coal or rock samples and coal-rock combination samples with different lithologies and combination methods under concentrated force are established by PFC2D software. Then the influence of coal or rock strength and combination methods on the internal stress transfer law and distribution evolution characteristics of coal-rock medium are discussed from the perspectives of macroscopic stress and mesoscopic force chain, respectively. The results showed that under concentrated load, the macroscopic stress transfer paths within pure coal or rock samples and coal-rock combination samples are primarily in the form of 'point source radiation'. However, when transferring between coal-rock interfaces, there is a certain interface effect. For pure coal or rock samples, differences in lithology does not change the transfer rules and macro distribution patterns of internal stress, but it can cause changes in internal unit transfer stress value and local area transfer direction. For coal-rock combination samples, the greater the difference in lithology between the two sides of the interface, the more likely the interface effect will occur. In addition, the internal stress transfer is also influenced by the relative stratigraphic relationships of coal and rock. When the stress is transferred from a higher-strength rock to a lower-strength coal mass, the interface effect will be more significant. However, regardless of the combination pattern, the locations where significant stress surges occur are always within the higher strength rock mass near the interface. The findings are helpful to understand the mechanical properties and failure mechanism of mining coal and rock mass, and provide a theoretical basis for the study of the mining-induced mechanical behavior of the floor under the action of the coal pillar.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
To explore the efficacy of different approaches of seminal vesiculoscopy surgery and the predictive factors of good treatment outcome.
A retrospective analysis of 68 patients who underwent seminal ...vesiculoscopy for hematospermia in our hospital from January 2015 to January 2021. According to different surgical approaches, they were divided into three groups: natural ejaculatory ducts (method A, 45 cases), assisted transurethral resection/incision of ejaculatory ducts (method B, 14 cases), fenestration in prostatic utricle (method C, 9 cases). We analyzed the recurrence rate of the three surgical approaches and the predictive factors of treatment efficacy.
The total recurrence rate after the seminal vesiculoscopy for hematospermia in this group was 32.35%. The postoperative recurrence rates of the three methods were 24.44% for method A, 50.00% for method B and 44.44% for method C, and there was no significant difference among the three methods (P > 0.05). The data of five predictors of 45 cases in method A group were included in the Univariate Logistic analysis, the results suggest that whether complicated with seminal tract stones/cysts was an effective predictor (OR 0.250, P = 0.022), which was still an effective predictor in the Multivariate Logistic analysis model (OR 0.244, P = 0.010).
The Transurethral seminal vesiculoscopy technique demonstrates a low postoperative recurrence rate in treating hematospermia. Among the various approaches, the intraoperative use of natural orifices through the ejaculatory duct exhibits the lowest recurrence rate. Additionally, seminal tract stones/cysts effectively predict favorable postoperative outcomes.
Human fingers possess stable high sensitivity and a wide range of tactile perception, attributed to the gradient microstructure and the interlocking collagen fiber on the skin's surface. However, ...challenges persist in achieving simultaneous enhancement of multiple functionalities in artificial skin. Inspired by the unique structure of the skin, a two‐step process involving ion diffusion‐induced and strong‐weak topological crosslinking is synergistically employed to fabricate a bilayer gradient hydrogel. Zn2+ initially diffuses to induce the formation of weak bonds, imparting elasticity. Subsequently, Fe3+/Zn2+ diffusion constructs a strong‐weak topologically crosslinked network, enhancing the toughness of the gel while reducing the brittleness associated with robust bonds. Due to its distinctive design, the gel employs an adaptive energy dissipation strategy subjected to large and small stress, ensuring high sensitivity (3.31 kPa−1, 0–2 kPa), wide sensing range (0.4–40.6 kPa), and exceptional stability (500 cycles). This flexible approach enables programmable design in three dimensions, including ion diffusion type, direction, and shape. This gel can detect the gentle brushing of feathers and human body movements. It utilizes significant differences generated by magnitudes of stress to perform binary information encryption. This study introduces a novel strategy for preparing skin‐like gels, offering promising potential for expanding their applications in complex scenarios.
The flexible network induced by weak Zn2+ diffusion undergoes simultaneous sacrifice and reconstruction when subjected to loading, endowing a bilayer gradient gel with high sensitivity. Through strong‐weak Fe3+/Zn2+ dual‐ion diffusion, a topological cross‐linked network is constructed, and the robust coordination imparts a wide detection range. Weak bonds, serving as a buffer, alleviate hysteresis induced by the fracture of brittle bonds.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Traditional artificial skin gels often only focuses on a single perspective and overlooks the necessity of multidimensional synergistic design for sensitivity enhancement. To address these problems, ...the innovative introduction of dual solvents on the surface of polyacrylamide/sodium alginate gel induces to the transformation of supramolecular interactions including ion coordination, crystalline alcohol, and phase separation, synergistically achieving adjustable wrinkle wavelengths (304.2 ± 19.9 to 2393.5 ± 95.9 µm) and modulated chemical compositions with tunable moduli (87.5 ± 3.3 to 157.6 ± 3.7 kPa). This flexible strategy allows the construction of long‐range ordered wrinkled microstructures of three‐dimensional surfaces and complex morphologies. Meanwhile, the bridge effect induced by crystalline alcohols directs the insertion of ethanol molecules into the polymer chains, effectively reducing intramolecular friction. Benefiting from the small wavelength and low modulus dominated by crystalline alcohol, the wrinkled gel exhibits extremely high sensitivity of 164 kPa−1 (<0.5 kPa) and wide detection range (44.3 kPa). The wrinkled gel remains stable high sensitive to detect micro‐ and large stress, tactile perception, and human motion behaviors. This work proposes a new strategy for constructing highly sensitive bioinspired skin from multiple dimensions, showing broad application prospects in the fields of bioengineering and behavioral cognition.
The bridge effect exhibited by dual solvent‐induced crystalline alcohols can effectively reduce the modulus of the hard shell and maintain a long‐range ordered wrinkled surface, synergistically achieving optimal sensitivity and wide detection range. Additionally, it facilitates the anchoring of ethanol within the gel system, leading to reduced intramolecular friction and improved stability.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
To solve the problem of stability control of coal pillar in steeply dipping coal seam (SDCS), based on the characteristics of surrounding rock structure and stress environment of the coal pillar, a ...special bearing structure of ‘roof-coal pillar’ combination is proposed through theoretical analysis. The mechanical model of inclined ‘roof-coal pillar’ structure is established, and the stress and strength characteristics of each element in the structure are deduced. Combining numerical calculations (PFC2D-FLAC2D coupling model) and physical similarity simulation, the stress evolution characteristics and failure mechanism of the ‘roof-coal pillar’ structure under the influence of mining were revealed. The results show that the coal pillar of SDCS is easy to form a ‘roof-coal pillar’ combined bearing structure with the roof strata. Under the influence of mining, the stress distribution and deformation evolution within the ‘roof-coal pillar’ structure show strong non-uniform and asymmetric characteristics. Among them, the stress distribution shows an ‘ellipse’ shape which is offset to the upper section, and the main deformation zone of the structure is a diagonal deformation distribution zone that runs through the coal and rock in the same direction as the stress offset. The failure of the ‘roof-coal pillar’ structural firstly occurs in the coal area near the coal-rock interface on the side of the lower section, and finally forms a diagonal failure crack running through the coal and roof, which is manifested as a diagonal shear failure mode. The findings can provide a theoretical basis for the stability control of coal pillars in multi-section mining of SDCSs and improve the safety production technology level of the working face.
In fully mechanized caving mining, the earlier the top coal enters the limit-equilibrium zone, the easier it is for leakage to be induced in front of the support. As the dip angle of the seam ...increases, the leakage of the top coal in front of the support drastically reduces the stability of the stope support-surrounding rock system. In this study, theoretical analysis, a physical simulation experiment, a numerical simulation, and field measurements were performed to consider the influence of the coal seam dip effect on the gradual deterioration of top coal for the first time, and quantitative characterization of the limit equilibrium boundary of top coal was realized based on analysis of the continuous damage medium mechanics. The results show that the two boundaries exhibit a consistent, asymmetric 'double arch' distribution along the incline. The top coal in the inclined upper-middle region of the working face is the first to enter the limit-equilibrium state, whereas the inclined upper and lower regions lag behind. The initial and final boundaries of the limit-equilibrium zone are distributed from 1.24 to 3.04 m and from 0.19 to −1.95 m in front of the coal wall, respectively. The distribution of the limit-equilibrium zone boundary was verified by the leakage times of the top coal in the working face. These results could provide reference information for evaluating stope support-surrounding rock systems in fully mechanized caving mining with steeply dipping coal seams.
Rheumatoid arthritis (RA) is an autoimmune disease in which certain immune cells are dysfunctional and attack their own healthy tissues. There has been great difficulty in finding an accurate and ...efficient method for the diagnosis of early-stage RA. The present shortage of diagnostic methods leads to the rough treatments of the patients in the late stages, such as joint removing. Nowadays, there is an increasing focus on glyco-biomarkers discovery for malicious disease via MS-based strategy. In this study, we present an integrated proteomics and glycoproteomics approach to uncover the pathological changes of some RA-related glyco-biomarkers and glyco-checkpoints involved in the RA onset. Among 39 distinctly expressive N-glycoproteins, 27 N-glycoproteins were discovered with over twofold expression significances. On the other hand, 13 proteins have been distinguished with significant differences in 53 distinctly expressed proteins identified in this study. Such an integrated approach will provide a comprehensive strategy for new potential glyco-biomarkers and checkpoints discovery in rheumatoid arthritis.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
As a public infrastructure service, remote sensing data provided by smart cities will go deep into the safety field and realize the comprehensive improvement of urban management and services. ...However, it is challenging to detect criminal individuals with abnormal features from massive sensing data and identify groups composed of criminal individuals with similar behavioral characteristics. To address this issue, we study two research aspects: pickpocketing individual detection and pickpocketing group identification. First, we propose an IForest-FD pickpocketing individual detection algorithm. The IForest algorithm filters the abnormal individuals of each feature extracted from ticketing and geographic information data. Through the filtered results, the factorization machines (FM) and deep neural network (DNN) (FD) algorithm learns the combination relationship between low-order and high-order features to improve the accuracy of identifying pickpockets composed of factorization machines and deep neural networks. Second, we propose a community relationship strength (CRS)-Louvain pickpocketing group identification algorithm. Based on crowdsensing, we measure the similarity of temporal, spatial, social and identity features among pickpocketing individuals. We then use the weighted combination similarity as an edge weight to construct the pickpocketing association graph. Furthermore, the CRS-Louvain algorithm improves the modularity of the Louvain algorithm to overcome the limitation that small-scale communities cannot be identified. The experimental results indicate that the IForest-FD algorithm has better detection results in Precision, Recall and F1score than similar algorithms. In addition, the normalized mutual information results of the group division effect obtained by the CRS-Louvain pickpocketing group identification algorithm are better than those of other representative methods.
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