Search

Aiming at the engineering background of shallow coal seam burial depth, thick soil layer, thin bedrock and strong disturbance of fully mechanized caving mining in the loess gully area of northern Shanxi Province, two methods of comprehensive numerical calculation and field measurement are used to explore the failure characteristics of overlying rock during mining. The simulation results show that: under the condition of strong mining disturbance, the destructive influence of mining will be transmitted from depth to shallow. With the increase of the mining distance of the working face, the displacement and deformation of the mining stratum has a cumulative effect, and the destructive effect of mining has a development process of vertical rapid development, vertical stagnation and horizontal expansion, vertical rapid breakthrough, and the ratio of the water-conducting fracture zone to the mining thickness is about 19.7; the field measurement shows that the destructive impact of mining on the 10108 working face has broken through the critical plane between the bedrock and the soil layer, the mining cracks are connected up and down, and the overlying rock layer in the goaf no longer has the ability to block water. The failure characteristics of mining overburden are mainly high-angle longitudinal fractures. The damage height of mining overburden will not be less than 198.2 m, and the ratio of the water-conducting fracture zone to the mining thickness will not be less than 22. The comprehensive research results show that: fully mechanized caving mining of thick coal seam results in more severe damage of overlying strata, and high angle of mining-induced overlying strata can lead to the development of water fractures. Although the viscous laterite with strong plastic has a restraining effect on the longitudinal development of mining-induced fractures, it cannot naturally bridge and lose the barrier of shallow unconsolidated strata and surface water in a certain period after mining at the working face. The ratio of the water-conducting fracture zone to the mining thickness is 10.5% and 9.5% different from the numerical simulation results and the empirical formula respectively. Therefore, reasonable water prevention and control measures should be formulated in time.

In order to solve the problem of converting a large amount of original GNSS receiver observation data into RINEX format files independent of the receiver during satellite positioning measurement in railway line engineering plane control networks, this paper used the C # language for secondary development of the program. The GNSS receiver observation data of Trimble Company was taken as the research object, and the syntax rules of the batch processing file of the GNSS receiver original observation data which provided by the company decoding program Convert To RINEX were analyzed. Then, the batch processing file calling method of the program was used to develop the Trimble GNSS observation data batch processor. After engineering verification, this batch of processor software could conveniently and quickly convert the massive raw data of Trimble GNSS receivers into RINEX format files independent of the receivers, and can be applied to various large-scale satellite measurement projects such as railway line engineering plane control network satellite positioning measurement. [ABSTRACT FROM AUTHOR]

Characterization of the dynamic change in the immunological landscape during malignant transformation from precancerous lesions to cancerous lesions in squamous cell carcinoma (SCC) is critical for the application of immunotherapy. Here, we performed single-cell RNA-Seq (scRNA-Seq) of 131,702 cells from 13 cancerous tissues of oral squamous cell carcinoma (OSCC), 3 samples of precancerous oral leukoplakia, and 8 adjacent normal samples. We found that tumor-infiltrating [CD4.sup.+] and [CD8.sup.+] T cells were functionally inhibited by immunosuppressive ligands expressed on various types of myeloid cells or neutrophils in the process of oral carcinogenesis. Notably, we identified a subset of myofibroblasts that exclusively expressed tryptophan 2,3-dioxygenase (TDO2). These [TDO2.sup.+] myofibroblasts were located distally from tumor nests, and both [CD4.sup.+] and [CD8.sup.+] T cells were enriched around them. Functional experiments revealed that [TDO2.sup.+] myofibroblasts were more likely to possess the ability for chemotaxis toward T cells but induced the transformation of [CD4.sup.+] T cells into Tregs and caused [CD8.sup.+] T cell dysfunction. We further showed that use of the TDO2 inhibitor LM10 attenuated the inhibitory states of T cells, restored the T cell antitumor response, and prevented the progression of OSCC malignant transformation in murine models. Our study reveals a multistep transcriptomic landscape of OSCC and demonstrates that [TDO2.sup.+] myofibroblasts are potential targets for immunotherapy., Introduction Oral squamous cell carcinoma (OSCC), a malignancy that occurs in the epithelium of the oral cavity, is the predominant type of head and neck squamous cell carcinoma (HNSCC). It [...]

Taking the 2S103 intelligent fully mechanized mining face of Wangjiata Coal Mine as an example, the specific implementation plan and application effect of intelligent fully mechanized mining face are analyzed, and the existing technical problems are summarized. According to actual situation of 2S103 working face, the intelligent frequency conversion speed regulation scheme of scraper conveyor and transfer machine is studied. By adding speed comparison and judgment module of the transfer machine and the scraper conveyor, the problem of overload and shutdown of the transfer machine due to the lag in speed control is solved, at the same time, it also guarantees the linked speed regulation operation of the transfer machine; Taking engineering quality and manual input as measuring index, the optimal coal mining plan is determined which combines memory cutting, automatic machine following and support moving, and manual adjustment; The shearer,hydraulic support and integrated liquid supply system are modified to improve safety, practicability and maintenance efficiency of related equipment, and eliminate a large number of potential safety hazards. By comparing and analyzing from aspecets of electricity consumption per ton of coal, coal cutting efficiency, reverse osmosis water consumption, personnel input, and small and medium repair costs, it is concluded that the intelligent fully mechanized mining face has achieved certain effects in energy saving, staff reduction, and material reduction. Technical problems existing in the practical application of intelligent fully mechanized mining face are summarized, in case of special structure,coal mining technology needs to be improved, the analytic function of video monitoring system needs to be perfected, etc. It is pointed out that to realize the smart mine, the research on safety monitoring system and smart brain should be actively promoted, and put forward some construction ideas and directions.

Taking the 6-2116 fully mechanized coal mining face of No.2 shaft of Nalinmiao Coal Mine as the engineering background, in view of problems of large coal consumption and difficult coal transport in abandoned roadway backfilling on coal pillar recovery working faces, a hydraulic coal unloading device of belt conveyor in underground coal mine was designed. The device is composed of support device, redirection device and hydraulic system. It is installed at intersection of main transportation roadway and auxiliary retracement channel. Using hydraulic pump station as power, the coal is unloaded from the belt conveyor by the support device and the redirection device cooperatively,and then the coal is transported to the abandoned roadway. Through the coal unloading device, the raw coal does not need to be lifted into ground and then transported to underground by trackless rubber truck, which improves economic benefit and filling efficiency, and reduces safety risk. Field industrial test results show that when the shearing speed of shearer is 0.8 m/min, the speed of scraper conveyor is 0.4 m/s, the speed level of transfer machine is low, the speed of belt conveyor is 1.0 m/s, and the extension length of support cylinder and redirecting cylinder is 0.7 m, the coal unloading device can realize continuous coal unloading, which meets needs of coal backfilling for the test working face and ensures normal advancement of the coal pillar recovery working face.

Metabolic fitness of T cells is essential for their vitality, which is largely dependent on the behavior of the mitochondria. The nature of mitochondrial behavior in tumor-infiltrating T cells remains poorly understood. In this study, we show that mitofusin-2 (MFN2) expression is positively correlated with the prognosis of multiple cancers. Genetic ablation of Mfn2 in CD8+ T cells dampens mitochondrial metabolism and function and promotes tumor progression. In tumor-infiltrating CD8+ T cells, MFN2 enhances mitochondria–endoplasmic reticulum (ER) contact by interacting with ER-embedded Ca2+-ATPase SERCA2, facilitating the mitochondrial Ca2+ influx required for efficient mitochondrial metabolism. MFN2 stimulates the ER Ca2+ retrieval activity of SERCA2, thereby preventing excessive mitochondrial Ca2+ accumulation and apoptosis. Elevating mitochondria-ER contact by increasing MFN2 in CD8+ T cells improves the efficacy of cancer immunotherapy. Thus, we reveal a tethering-and-buffering mechanism of organelle cross-talk that regulates the metabolic fitness of tumor-infiltrating CD8+ T cells and highlights the therapeutic potential of enhancing MFN2 expression to optimize T cell function. Editor's summary: Organelle cross-talk plays a fundamental role in cell biology, but how this cross-talk controls tumor-infiltrating CD8+ T cells (TILs) is not understood. Yang et al. investigate the role of MFN2 in CD8+ TILs, identifying that mitochondrial interaction with the endoplasmic reticulum (ER) is required for metabolic fitness and antitumor activity. Through interaction with SERCA2 on the ER, MFN2 was required for mitochondria-ER contact and Ca2+ homeostasis. MFN2 expression was associated with better survival in patients with cancer, and promoting MFN2 expression in CD8+ T cells improved response to immune checkpoint blockade in mice. Together, these findings identify a critical role for MFN2 in regulating the metabolism, function, and survival of CD8+ T cells and suggest that boosting MFN2 expression is an attractive avenue for improving immunotherapy. —Hannah Isles [ABSTRACT FROM AUTHOR]

Purpose: Human body is sensitive to low-frequency excitation, which can not be suppressed effectively by the suspension control strategy that only controls the damper. This paper focuses on improving the vehicles' vibration isolation performances in low-frequency excitation by adjusting the stiffness and damping of suspension simultaneously. Methods: By using the designed acceleration-driven-stiffness fuzzy control strategy (ADSFC) and Skyhook based fuzzy control strategy (SHFC), the internal pressure of air spring and the current of magnetorheological damper are controlled separately to realize the adjustment of stiffness and damping. Results: The simulation results show that, the performance of the proposed control strategies are better than the passive suspension in up-step excitation and random road excitation. In particular, by using ADS-SHFC, the peak values of the sprung mass acceleration, the suspension dynamic deflection and the tire dynamic deflection are reduced by 59.4%, 48.3% and 59.4% respectively comparing with the passive suspension. Conclusion: The proposed control strategies are different from the conventional control methodsthat only controls the damping, this study is one of the first attempts to enhance thelow-frequency vibration isolation by changing the stiffness using control strategies. The simulation results verify the effectiveness of the proposed control strategies to improve the vibration isolation performance under low-frequency excitation. [ABSTRACT FROM AUTHOR]

This paper proposed a minimum transmitted load (MTL) control method for drop-induced shock isolation mounts (SIM) with magnetorheological energy absorbers (MREAs). MTL control method consists of two parts of maximum damping force (MDF) control and one part of constant acceleration (CA) control, which can make the payload stop after fully utilize MREA stroke (soft landing) with minimum transmitted load. The control algorithm of MTL control method is derived in a single-degree-of-freedom (SDOF) system. The relationship between the controllable velocity range of MTL control method and parameters of shock isolation mounts is also derived. An optimal control method selection criterion between Bingham number (BN) control method and MTL control method is developed. The performance of MTL control method and selection criterion are shown by applying to the SIM system with variable drop velocities and system parameters. Results shows that MTL control method has the minimum transmitted load and the selection criterion is feasible. [ABSTRACT FROM AUTHOR]

This paper proposed an extended constant deceleration (ECD) control method that can be used in the shock mitigation system with magnetorheological energy absorbers (MREAs). The ECD control method has three sections: zero controllable force (ZCF) section, constant deceleration (CD) section, and maximum damping force (MDF) section. Under the control of ECD, the system can stop at the end of MREA stroke without exceeding the maximum allowable deceleration. The ECD control algorithm is derived in a single-degree-of-freedom (SDOF) system. The controllable velocity range and the required controllable damping force of ECD control method are also derived, which can provide feasible solutions for the design of shock isolation system with MREAs. The performance of ECD control method is shown by applying to the drop-induced shock mitigation system with different drop velocities, different maximum controllable damping force, and MREA stroke. The results shows that the ECD control method not only has a large controllable velocity range and small controllable damping force requirement, but also can minimize the load transmitted to the system. [ABSTRACT FROM AUTHOR]

This research presents a minimal maximum deceleration (MMD) control method which can be used in the shock mitigation system with magnetorheological energy absorbers (MREAs). The proposed control method can make the payload stop at the end of the available MREA stroke with the lowest maximum deceleration, which does not exceed the deceleration threshold value and lead to the lowest occupant injury probability. The shock mitigation system controlled by MMD will experience constant deceleration control stage and maximum damping force control stage while making full use of the available MREA stroke. The comparative performance of the MMD control method with Bingham number (BN) control, constant deceleration (CD) control and minimum duration deceleration exposure (MDDE) control is shown. Then, the controllable drop velocity range and the required maximum MREA controllable damping force range of MMD control method is calculated. Subsequently, the optimal control method selection criterion among BN control method, CD control method and MMD control method is developed. Finally, the optimal selection criterion is applied to the drop induced shock mitigation system with varying payload velocity, payload mass (occupant type) and the maximum controllable damping force of MREA. [ABSTRACT FROM AUTHOR]