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In order to solve the problems of ignoring multi-dimensional load characteristics, cumbersome modeling process and long design cycle in the design process of hydraulic support in steeply dipping angle coal seam, combined with the load characteristics of hydraulic support in large dip angle pseudo-inclined working face, the design system of large dip angle hydraulic support is developed. Based on the comprehensive research methods of motion simulation, strength test and physical experiment, taking the design of ZY5000/15.5/38 hydraulic support for steeply dipping angle coal seam as an example, the mechanical model is established according to the multi-dimensional stress characteristics of hydraulic support in large dip angle pseudo-inclined stope. The spatial load characteristics of large dip angle hydraulic support are analyzed, and the mechanical linear matrix of top beam and shield beam of hydraulic support in pseudo-inclined working face is established. The design system of hydraulic support is built by using VB.NET as the development language combined with linear matrix and SOLIDWORKS secondary development modeling software, and a good human-computer interaction user interface is developed. The research and analysis show that the trajectory range of the front end of the top beam of the model hydraulic support generated by the system is about 48 mm, and the trajectory curve of the front end of the top beam of the support satisfies the characteristics of double torsion line. The maximum stress value of the model support is 146.7 MPa, which is far less than the equivalent stress value of the material yield, and the maximum deformation displacement is not more than 0.531 mm. The working resistance of the physical model hydraulic support with a similarity ratio of 1:5 is about 38 kN. The loading characteristics of the top beam and the shield beam of the support are tested under different conditions. The mechanical data of the model support in the experiment are basically consistent with the mechanical data generated by the system, and the experiment meets the motion requirements and bearing characteristics of the support in the stages of initial support, resistance increase, constant resistance and pressure relief. The research results reflect the good adaptability of the model hydraulic support under the design system, which has certain scientific and practical significance for enriching the design theory of hydraulic support in steeply dipping angle coal seam and guiding the design and production of hydraulic support.

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.

Abstract To study the fracture instability characteristics and fracture mechanism of overlying strata in steeply dipping and large mining height stope, through the combination of physical simulation experiment, numerical calculation, theoretical analysis and field measurement, the correlation between the evolution of mining stress field and the fracture of overlying strata in large mining height stope under the effect of dip angle is analyzed, and the stress transfer path and the fracture mechanism of overlying strata are revealed. Finally, the influence mechanism of key strata on the evolution of the mining stress field of overlying strata is explained. The research shows that under the influence of gravity dip angle effect and mining height increase, the mining stress is non-equilibrium transferred and evolved in space, and the principal stress field presents the characteristics of partition evolution. The fracture trajectory of rock strata is multi-step and “八” shaped, and the inclined masonry structure and multi-step key strata form a cooperative bearing structure. The key layer of the ladder is the stress transmission structure between the caving zone and the stress arch, and the high stress in the overhanging area under the main roof is transmitted to the advanced roof. With the increase of dip angle, the height of the caving zone decreases, and the fracture range of ladder and principal stress arch decreases. The cracks in the middle and upper broken rock blocks increase, and the instability of the “high ladder rock layer” is easy to induce the simultaneous fracture of the “inclined masonry structure”, resulting in regional unbalanced instability and impact. The research results can provide some reference and guiding significance for the stability control of surrounding rock in longwall stope with steeply dipping.

The hydraulic support is the core of the stability of the ‘surrounding rock and equipm ent’ system in the pitching oblique working face of steeply dipping coal seam. The existing hydraulic support structure can not meet the requirements of spatial stability of pitching oblique mining, which seriously affects the safe and efficient mining of working face under such conditions. Taking the pitching oblique working face of steeply dipping coal seam as the research background, the comprehensive research methods of engineering analogy, structural kinematics analysis and numerical simulation are used to analyze the stability characteristics of ‘support-surrounding rock’ in the pitching oblique working face of steeply dipping coal seam. Based on ZY7000/22/45 hydraulic support, a new parallelogram hydraulic support is invented, the structural rationality design is carried out, and the kinematic response characteristics of key components are analyzed.The research shows that the non-uniform filling of the caving gangue and the crushing, pressing and pushing effect of the gangue on the support are the key factors affecting the stability of the support. The parallelogram top beam and the base are more suitable for the pitching oblique working face. The arrangement of the top beam, base and column of the parallelogram support is parallelogram. The special-shaped shield beam, the rear connecting rod, the oil cylinder connecting rod and the base constitute a flexible four-link structure. The column of the parallelogram support is the main bearing structure, and the cylinder connecting rod is the main motion mechanism. The main influencing factors of its motion characteristics are the distance between the upper and lower column sockets and the distance between the front and rear connecting rods and the hinged position of the shield beam. The shield beam and the rear connecting rod are the key to the position and posture control of the support, and there is no double torsion line during the movement of the support. The research results provide a type selection for the support of this kind of working face, which ensures the safe production of this kind of coal seam to a certain extent.

The structure and stress environment of the surrounding rock at the longwall mining area in the steeply dipping coal seam are alienated, and the composition factors and disaster modes of the ”support and surrounding rock” system in the working face are affected. This leads to some frequent safety accidents in the working face, low coal extraction rate, and high roadway excavation rate. This paper analyzes the mining mechanics behavior of surrounding rock of in the steeply dipping coal seam and proposes a technological concept of partial backfill non-pillar mining in the longwall faces of steeply dipping coal seam. During the process of advancing the working face, partial backfill is carried out along the inclined direction in the lower part of the goaf. The filling body not only forms a gob-side roadway with the support effect of the roadway side, but also eliminates the protection coal pillar, achieving a non-pillar mining. At the same time, the length of the filling and compaction area at the lower dip of the working face is increased, enhancing the stability of the ”support and surrounding rock” system of the working face. Based on the characteristics of the longwall mining area in the steeply dipping coal seam, the partial backfill process of the steeply dipping coal seam paste was optimized and determined. And the partial backfill recovery system and mining and filling process in the steeply dipping coal seam were designed. By using a combination of theoretical analysis, simulation experiments, and numerical calculations, the regulatory mechanism of partial backfill on the mechanical behavior of surrounding rock at the longwall mining area in the steeply dipping coal seam was analyzed. The results show that the filling body affects the deformation and failure of the main roof rock beam, as well as the bearing characteristics of the coal and rock mass on the lower side of the mining area. The deformation of the main roof and the roof of the head entry, as well as the constraints on the coal and rock mass on the lower side of the head entry, all decrease with the increase of filling length. In order to prevent the hanging roof disaster in the unfilled area of the goaf, the filling length should not exceed 1/3 of the working face length. The partial backfill body restricts the fracture of the roof in the lower area of the working face, reduces the formation layer of the critical zone of the overlying rock, forms a stable roadway, and reduces the deformation of the surrounding rock gob-side roadway retained. At the same time, the length of the filling area at the lower part of the working face increases, and the length of the unstable area of the middle and upper surrounding rock structures decreases, improving the stability of the ”support and surrounding rock” system. The filling body changes the stress transmission path of the surrounding rock in the mining area, bearing part of the overlying rock load. The side abutment pressure on the lower side of the working face and the front advanced pressure both decrease with the increase of filling length, and the front support pressure in the lower filling area of the working face has the greatest decrease. The stress state of the gob-side roadway and the working face is improved. Technology of partial backfill non-pillar mining in the longwall faces of steeply dipping coal seam has the advantages of effectively improving resource recovery rate, reducing the roadway drivage ratio, alleviating the tension of mining and replacement, and strengthening the stability of the ”support and surrounding rock” system in the working face. It is of great scientific significance for guiding the green, safe, and efficient mining in the steeply dipping coal seam.

Abstract 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.

The steeply dipping coal seam is one of the main forms of coal storage in China. It is widely and regionally distributed. According to incomplete statistics, twenty-six provinces, autonomous regions and municipalities directly under the central government are involved in the mining of such coal seams, with abundant reserves, large production and high production concentration in the central and western regions. It shows diversity and complexity in terms of the conditions of existence, with different regions having different coal formation periods and different tectonic control processes, forming diverse and complex mining conditions and giving rise to different mining technology requirements. The mining of steeply dipping coal seam is technically difficult. The asymmetry of the movement and damage of the peripheral rock in the mining area affected by the inclination angle of the coal seam is obvious, and the difficulty of the stability control of the support system and equipment, the matching and coordination of the “three machines”, the layout and support of the mining roadway, and the safety guarantee of the “human-machine” environment at the working face has increased significantly, which seriously restricts the safe and efficient mining of the mine. This has seriously restricted the improvement of safe and efficient mining. The regional economic demand for the mining of steeply dipping coal seam is strong. This kind of coal seams and the production of more concentrated areas are mostly seen in the coal industry-based resource cities, the economic structure is relatively single, the safe and efficient development and utilization of coal resources for the regional energy supply, people’s livelihood, economic stability has the role of the bottom of the pocket, the demand is urgent. For a long time, mining technologies for the steeply dipping coal seam changes focus on solving the “difficult” and “need” contradiction. In the coal mining methods and techniques, strata control theory and technology, complete sets of equipment development and application of the three aspects of continuous improvement, innovation, development, to achieve the transformation from non-mechanized to fully-mechanized mining, the level of safety and production efficiency has increased dramatically, the personnel labor intensity has decreased dramatically, and the operating environment has improved significantly. In the mid-1990s, Lvshuidong Coal Mine of Sichuan Coal Industry Group Limited Liability Company successfully realized longwall fully-mechanized mining in steeply dipping coal seam with medium mining height for the first time, breaking through the "forbidden zone" in this filed. Under this demonstration, the three pioneering engineering practices of longwall fully-mechanical mining of steeply dipping coal seam with thick mining height, steeply dipping coal seam with large mining height, and longwall fully-mechanical mining of steeply dipping coal seam with thin mining height in pseudo-inclination have been successful successively, which innovated the non-linear limiting arrangement of the working face and the way of adjusting the slanting, established a multi-dimensional interactive control mode of the system stability of the “bracket-surrounding rock”, and researched and developed the “support and stability and heavy weight, high-strength and light-weight, safe and reliable, and matching synergistic” complete set of equipment of the working face, which has achieved good results, and the scope of application of the comprehensive mechanized mining technology has further been widened. At the same time, there are still many key scientific problems and technical bottlenecks that need to be broken through in the mining of steeply dipping coal seams, resulting in a large gap between the intelligence level and that of the flat/gently inclined coal seams. Research on the mining dynamics of coal and rock bodies in inclined bedded coal beds, revealing their control mechanisms on the disaster of the surrounding rocks in the mining field, and realizing quantitative characterization need to be further strengthened. It is necessary to further clarify the multi-dimensional dynamic process and law between the system of “rock-bearing structure - mining equipment group”, improve the theoretical and technological basis of “multi-dimensional dynamic multi-objective synergistic control of equipment and surrounding rock”, and realize the transformation and application of the technology. On the basis of breakthroughs in scientific issues, we will carry out systematic technological innovation and research and development of coal mining methods, mining techniques, rock formation control, and complete sets of equipment, so as to crack the bottleneck of the constraints on the double enhancement of “safety and efficiency” in the mining of steeply dipping coal seams, and make the upper limit of the inclination of the steeply dipping coal seams for comprehensive mechanized mining extend upward under the prerequisite of reliable technological safeguards, so as to lay the foundation for the realization of automated and intelligent mining.

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.

AbstractWhen the working face of a steeply dipping coal seam crosses a fault, the dynamic disturbance caused by the mining load induces fault activation, causing large deformation and failure of the roadway. In this study, a physical similarity simulation and numerical calculation method were used to determine the main factors that the deformation and failure of fault zone roadway and reveal the underlying mechanisms. The results show that when crosses a fault, the high static load formed by the coupling of mining stress and fault pillar stress induces mining stress-type fault activation, which leads to large deformation and damage to the roadway in the fault zone. The main controlling factors are the fault location and mining load intensity. In terms of fault location, the vertical stress concentration away from the roadway side of the fault surface was high, the principal stress deflection angle was large, and the surface deformation of the fault on the roadway left side was the greatest. In terms of mining load intensity, the deflection angle of the principal stress of the surrounding rock initially increased and then decreased, and tensile failure easily occurred near the fault surface. These results provide a reference for roadway support.

Taking the steeply dipping and large mining height working face of a mine as the engineering background, through the combination of physical simulation experiment, numerical calculation, theoretical analysis and field monitoring, based on a comprehensive analysis of the deformation and failure characteristics of the macrostructure of surrounding rock, the roof breaking mechanism and support instability characteristics of large mining height working face under the angle effect are studied. The research shows that due to the influence of the dip angle of the coal seam, the roof stress is asymmetrically deflected along the tendency, and the load of the overlying strata is transmitted to the upper and lower coal bodies with the stress-deflection boundary as the boundary, resulting in the deformation and failure of the roof and the filling showing obvious asymmetric characteristics. With the increase of dip angle, the asymmetric characteristics of roof stress transfer are enhanced, the stress release arch is reduced, the height of caving zone is reduced, the deformation and failure area is gradually moved up, and the regional characteristics of roof loading and deformation and failure are more obvious, which leads to the significant increase of unbalanced loading degree and instability probability of supports in different areas. Combined with the actual production, the prevention and control measures of hard roof caving and support crushing in fully mechanized mining face with steeply dipping seam and large mining height are put forward.

Coal wall of large mining height face in steeply dipping coal seam has large free height, wide free movement space and poor self-stabilization balance, coal wall is not an isolated body in the face, it can form a load-bearing structure with the surrounding rock, supports and other mediators, and the mining behavior is closely linked. The dip angle effect can easily promote the dissimilation of the coal wall bearing environment, complicate its response behavior, increase the difficulty of coal wall and surrounding rock stability control, and restrict the safe and efficient production of the face. In order to solve the problem of coal wall stability control of large mining height face in steeply dipping coal seam, theoretical analysis and numerical calculation are comprehensively used for research. The stress in the plastic zone of large mining height face in steeply dipping coal seam increases exponentially, there is an asymmetric arch residual stress influence zone in the vicinity of the coal wall, the plastic zone breadth is dissimilated in different regions, and the width from large to small is the upper, middle and lower part, and the distribution pattern is in the shape of stepped arch, coal in the plastic zone bears repeated pressure, and will be enhanced with the expansion of plastic zone. As the mining height increases, the residual abutment pressure near the coal wall decreases, the compressive strength, displacement value and disturbed range of the coal in front of the coal wall will increase. The stress and transport of the coal wall under the dip angle effect develop in a zonal manner, in which the stress distribution is lower> upper> middle, while for the displacement is middle> upper> lower. In addition, the working face inclination under the oblique angle will lead to the transformation of the coal wall instability mode, when the oblique angle is large, the dip angle of face is small, the compression component of abutment pressure is enhanced, and the external convex spalling mainly occurs. On the contrary, it’s the sliding instability under the coupling of mining stress and self weight. The comprehensive analysis shows that the coal wall mining behavior is regionally heterogeneous under the coupling effect of dip angle and mining height, and because the stress unloading and migration in the middle and upper part of the face are larger, therefore the two regions should be the key prevention and control areas for coal wall instability of large mining height face in steeply dipping panel.

Steeply dipping seam is still internationally recognized as a complex and difficult coal seam. There are many and extensive coal seams in China with excellent coal quality. In recent ten years, the advanced longwall fully-mechanized mining technology of steeply dipping seam has developed rapidly, the working environment has been improved, the labor intensity has been reduced, and the safety level has been improved. However, there have been some urgent problems to be solved, such as low output and poor efficiency. The economic advantages and investment benefits of fully-mechanized mining technology cannot be fully exerted, which restricts the efficient and sustainable development of fully-mechanized mining in steeply dipping seam. Based on years of systematic research and engineering practice, the comprehensive analysis shows that the production efficiency of fully-mechanized mining in steeply dipping seam is mainly restricted by six factors, such as geology, equipment, technology, personnel, management and others, and the weight of each factor is determined. According to the weight of each influence factor, we should take targeted measures such as Precise detection, precise maintenance, precise operation, precise management, precise training and precise supplement In particular, we should pay more attention to the development direction of mining automation and intelligence, and take it as the core accurate countermeasure for promoting production and efficiency of fully-mechanized mining in steeply dipping seam, so as to fundamentally change the passive situation of large number of people and low production efficiency of fully-mechanized mining in steeply dipping seam. The goal of safety, high yield and reducing human efficiency in long wall comprehensive mining in steeply dipping seam is realized.

AbstractIn this paper, taking a mine in Xinjiang as the engineering background, through the combination of physical simulation experiment, 3DEC numerical calculation, theoretical analysis and field monitoring, the fracture evolution characteristics of overlying strata and its influence on the stability of support under unbalanced loading conditions are systematically studied. The results show that under the action of gravity-dip effect, the non-uniform filling of gangue leads to the typical cross-layer migration characteristics of overburden caving shape and roof bearing arch. The unstable inclined masonry structure is formed in the middle and upper areas, which is prone to rotation and sliding instability, forming impact pressure. The mining stress of the overlying strata changes significantly due to the mining of the coal seam. The lower the overlying strata, the greater the peak stress, the smaller the stress value in the goaf, and the greater the stress change. The amplitude and instability probability of the support migration increase with the decrease of the working resistance of the support, the increase of the friction between the roof and the support, and the increase of the partial load of the support. Finally, the prevention and control measures of roof caving crushing support in steeply dipping and large mining height working face are put forward.

Vegetation plays a crucial role in maintaining the balance between nature, water and soil resources. However, understanding its impact mechanisms in arid and semi-arid areas remains limited. This study aims to analyze the spatial–temporal characteristics of the vegetation leaf area index (LAI) and climate elements in typical regions of northwest China and the correlations between LAI and climate elements; it also aims to explore the influence of regional vegetation growth on climate change. The results reveal significant correlations between LAI and various climate elements. Specifically, within the same region, surface temperature, precipitation, vegetation transpiration, and total evaporation show positive correlations with the LAI, whereas surface albedo shows a negative correlation. Vegetation may affect climate through both heat and water exchange between the land and atmosphere. Increased vegetation leads to the enhanced absorption of solar radiation by the land surface, elevating surface temperature. Increased levels of vegetation also increase vegetation transpiration and total evaporation, increasing the water vapor content in the atmosphere and thus leading to increased surface precipitation. Therefore, vegetation distribution plays a role in climate change, and ecological restoration projects in the northwest region hold significant potential for addressing ecological challenges in its arid and semi-arid areas.

Abstract Background CYP4 subfamily V member 2 (CYP4V2) polymorphisms are related to venous thromboembolism. However, the influence of CYP4V2 polymorphisms on the susceptibility to ischemic stroke (IS) remains undetermined. Methods We selected and genotyped five polymorphisms of CYP4V2 in 575 cases and 575 controls to test whether CYP4V2 variants were associated with the risk for IS in a Chinese Han population. Genotyping of CYP4V2 polymorphisms was performed using the Agena MassARRAY platform. Logistic regression analysis was used to assess the association between CYP4V2 polymorphisms and IS risk by calculating odds ratios (ORs) and 95% confidence interval (CI). False-positive report probability analysis was applied to assess the noteworthy relationship of the significant findings. Results CYP4V2 rs1398007 might be a risk factor for IS (OR = 1.34, 95% CI 1.05–1.71, p = 0.009). Specially, confounding factors (age, gender, smoking and drinking status) might affect the relationship between rs1398007 and IS susceptibility. Moreover, rs1053094 and rs56413992 were associated with IS risk in males. Multifactor dimensionality reduction analysis showed the combination of rs13146272 and rs3736455 had the strongest interaction effect (information gain value of 0.40%). Furthermore, genotypes of rs1398007 (p = 0.006) and rs1053094 (p = 0.044) were associated with the levels of high-density lipoprotein cholesterol (HDL-C) among healthy controls. Conclusion Our results first provided evidence that CYP4V2 rs1398007 might be a risk factor for IS, which provides instructive clues for studying the mechanisms of CYP4V2 to the pathogenesis of IS.

Xinjiang is a typical arid and semi-arid Mountain basin system, which make the regional ecosystem extremely fragile. Studying the influence of climate on vegetation is conducive to qualitatively analyze the change trend of vegetation coverage in this region. Therefore, utilizing vegetation coverage and main meteorological elements (temperature, precipitation, relative humidity, sunshine hours) data in Xinjiang province, this paper carried out the influence of multiple meteorological elements on vegetation coverage changes, and constructed a model of the impact of multiple meteorological elements on the growing season vegetation coverage based on random forest. The model can better simulate the vegetation coverage in 2017 and 2018, with an average error of 0.027, in consequence it can well forecast whether the vegetation is high-density or low-density in this area. Correlation analysis and variable importance show that the critical meteorological factors affecting vegetation cover change are relative humidity and sunshine hours, accounting for 73% of the vegetation coverage area. The results are helpful to understand how meteorological factors affect the vegetation coverage, and then provide a theoretical reference for the construction of ecological security in Xinjiang.

The fractured reservoir is one of the significant petroleum reservoir types in China, representing over one-third of total reserves. The Kuqa Depression in the Tarim Basin is dominated by fractured low-porosity sandstone gas reservoirs with characteristic tight matrix, developed fractures, and edge and bottom water. However, the continued development of these reservoirs has led to various problems, including strong reservoir heterogeneity, low well control, complex gas-water relationships, and early water invasion. Addressing these issues requires a detailed understanding of the reservoir’s geological characteristics. One method for achieving a fine reservoir description is through the use of 3D geological modeling. This high-level, comprehensive characterization technique is widely used throughout the entire life cycle of oil and gas field development. A 3D geological model can accurately predict the actual underground reservoir characteristics and provide a geological basis for later numerical simulation work. Based on a study of the geological characteristics of the Kuqa Depression in the Tarim Basin, a 3D geological modeling technique was developed, which includes structural modeling, facies modeling, petrophysical modeling, and fracture modeling. This technology has been successfully applied to many deep gas reservoirs in the Kuqa Depression of the Tarim Basin, leading to enhanced gas recovery.

Abstract The precipitation in the Qilian (QMA) and Tienshan (TMA) mountain areas is one of the main sources of subsurface and surface water in northwestern China (NWC). Based on two datasets, CN05.1 and station‐observed daily precipitation, we found that summer precipitation in 1979–2020 exhibited an increasing trend in NWC. The results of rotation empirical orthogonal function (REOF) analysis also separated the increased precipitation patterns in the QMA and TMA from the other REOF modes; the proportion of the precipitation of these areas to the total NWC summer precipitation substantially increased (0.12%⋅year−1 and 0.03%⋅year−1, respectively). According to the moisture budget, the evaporation changes in the QMA and TMA were coherently coupled with precipitation, which suggested the feedback between increasing evaporation and precipitation with the recently warming climate. The precipitation increase was larger than that of evaporation, indicating a net wetting trend in the QMA and TMA. The increase in zonal horizontal and vertical moisture advection terms contributed more to the increased precipitation in the QMA. The increase in meridional moisture advection contributed more to the increased precipitation in the TMA. We concluded comprehensive frameworks of the water vapor transport in climate change in mountain areas in NWC which aimed to contribute to the understanding of arid region hydrology.

Paste composite filling mining is one of the effective ways to realize green mining. In order to study the movement and deformation characteristics of overlying stratum in paste composite filling stope, taking the test mine as the engineering background, a mechanical model of movement and deformation of roof rock beam in paste composite filling mining was established by combining theoretical analysis, physical simulation and numerical simulation. The movement and deformation laws of main roof, sub-key stratum and main key stratum in the process of working face advancing under the conditions of multiple factors (mining height, filling ratio and buried depth) were analyzed. The results show that the displacement contour of overlying stratum is inverted trapezoid in the process of advancing working face which is unfilling or filling 2/3. The subsidence of stratum near the coal seam is larger, and the subsidence of stratum with higher distance from the coal seam is smaller, and the maximum subsidence point of overlying rock appears near the side of the open-off cut. With the increase of mining height, the range of overlying rock caving zone becomes larger, and the maximum subsidence value gradually increases. When the paste filling ratio of the working face increases, the collapse range of the roof decreases, the overall compression of the collapsed rock decreases, and the effect of control on the movement and deformation of the overlying rock is obvious. The subsidence of overlying stratum increases with the increase of buried depth of working face, but it does not change much. The deflection value of the roof rock beam changes slowly at both ends of the propulsion due to the support of the coal wall. The closer to the middle, the greater the change. The results of this study can provide an important reference for the control of the roof stability and surface subsidence of the paste composite filling mining.

Revealing the space-time evolution characteristics of overlying strata deformation and failure is the key for safe and efficient mining of steeply dipping coal seam. In this paper, based on the physical similarity simulation experiment and field measurement method, the non-uniform filling characteristics of gangue in gob and the roof migration law are comprehensively determined, the evolution characteristics and distribution patterns of the abutment pressure in the upper and lower sections, the distribution characteristics of the working resistance of the support, and the regional strata behavior law in the mining process are analyzed, and the technical measures for the stability control of the support in steeply dipping coal seam are put forward. Results shown: With the advancing distance increases, the accumulation range of gangue increases, and the inverted triangle airspace begins to appear repeatedly in the gob behind the support. In the deep gob, the angle between the gangue pile and the horizontal plane decreases continuously from the lower part to the upper part along the inclined direction. Horizontal displacement, vertical displacement and combined displacement of roof show an evolutionary trend of ‘increase – stability’. The peak displacement position moves from the upper part to the middle part of the working face, which is located at the hinge point between the broken block and the failure envelope surface. The evolution of abutment pressure of headgate and tailgate T-junction shows a trend of ‘increase – stability’. The peak and concentration coefficient at headgate T-junction are greater than tailgate T-junction. The load imbalance characteristics of the support in working face are obvious, and the basic characteristics along the inclined direction are the largest in the middle area, the second in the upper and the smallest in the lower area. The initial force and working resistance of support should be improved, and the position of the support should be adjusted in time in practical engineering. The results provide reference and guidance for practical production.

In order to obtain the flow trend of particles in the shaft coal pocket, Lay a foundation for the research on the stability of shaft coal pocket wall in coal mine. The flow trend of particles in the process both coal unloading and sand unloading is studied. The study methods are used by physical similarity simulation and numerical simulation experiment. The results show that the loose particles are divided into “three zones” in the longitudinal direction. As a whole, the particles in the shaft coal pocket is characterized by “two circles” which is the axis area and the bunker wall area. The better fluidity in the core, but the worse fluidity close to the bunker wall. The flow trend of the particles in the middle warehouse is as follows: the particles in the smooth passage in the central area flow out first. After flow out, the particles in this area will be filled by the particles in its upper area, then the outflow continues, the loose particles in the outer area of the middle flow out last. The particle flow trend in the natural flow area under the bearing structure is as follows: the loose particles in the funnel under the structure flow out according to the natural state. Due to the protection of its upper conical shell structure, the pressure of loose particles in this area are smaller than the upper area. which shown random natural outflow when coal outflow. The flow trend of bulk in the silo is basically consistent with the experimental results of numerical simulation.

Coal gangue is widely used as a filling material in coal seam mining. During the gangue filling in steeply dipping coal seam, the loading rate, gangue gradation, and filling speed have an important impact on the deformation and failure of gangue, and further affect the bearing of gangue on overlying strata and the control of surrounding rock movement and deformation. Therefore, this article uses a self-made steel cylinder to conduct a gangue compression test on the HCT pressure testing machine. The research analyzes the influence of loading rate, gangue gradation, and filling rate on the deformation law of gangue in the compression process. After completing the test, the gangues with different particle size groups were rescreened, weighed, and recorded to analyze the crushing situation in the compression process. The results show that loading rate, gangue gradation, and filling speed have greatly influenced filling gangue's bearing capacity, deformation, and crushing rate. The larger the loading rate of gangue, the greater the bearing capacity and deformation of gangue, and the higher the crushing rate of gangue. The smaller the gangue gradation, the smaller the deformation, and the stronger the resistance to deformation. A more optimized gangue gradation ratio is obtained according to the distribution law of the mass proportion of gangue with different particle size groups after compression. The faster the filling speed of manual filling gangue, the greater the strength and deformation of the gangue body. Moreover, the faster filling speed can effectively improve when the strength reaches the peak and deformation tend to be stable. The results can provide theoretical guidance for the local filling of artificial gangue in the longwall working face of steeply dipping coal seam.

The gasification kinetic modelling of two Victorian brown coal (Yallourn and Maddingley) chars and the validity for entrained flow gasification were investigated in this study. The study was conducted in a thermogravimetric analyzer (TGA) at 750–1100 ℃, 30%–90% CO2 concentration using different char particle sizes within 20–106 µm. It was found that random pore model and modified volumetric model are applicable for TGA results, but volumetric model and grain model are not. The effect of particle size under 106 µm on gasification rate is very limited. Activation energies of Maddingley char and Yallourn char in CO2 gasification are 219–220 and 197–208 kJ/mol, respectively. The pre-exponential factors are in the same order of magnitude, and they increased as particle size decreased. A mathematical model was developed to predict carbon conversion over time for entrained flow gasification of Victorian brown coal chars at 1000–1400 ℃.

Many recent examples have shown that rockfalls can occur in underground steep coal mines. The stratigraphic circumstances, block formation mechanism, and cumulative damage effects of rockfalls in the longwalls of a steeply dipping coal seam (SDCS) make them detrimental to workplace safety. Therefore, this study examined an approach for mitigating rockfall hazards in SDCSs. A passive mesh system was installed to prevent the propagation of rockfalls, which decreased the number of collisions between the falling rocks and mining equipment. The interactions of the falling rocks and passive mesh were studied using a series of full-scale numerical impact tests. The following conclusions could be drawn. The displacement of the mesh increased with the rockfall kinetic energy, showing the characteristic of strain hardening. The peak stress appeared near the contact area between the rockfall and mesh, and it spread to the mesh edge in an X-shaped pattern. Stress concentrations were likely to occur in areas that were in direct contact with the mesh and mesh edges. The displacement of the mesh increased when the incidence angle increased, and the number of mesh cells entering the plastic state increased significantly. The internal energy ratio increased with an increase in the incidence angle, indicating that a greater incidence angle led to a larger amount of kinetic energy being transferred from the block into the internal energy of the passive mesh. Finally, the method was verified by comparing the numerical test with the on-site damaged equipment. The high replacement frequency of a passive mesh system and the annual fatality rate in the longwalls of SDCS were significantly improved. This study provided the design for a drapery mesh system for rockfall disaster prevention, particularly the mitigation of rockfall hazard risks in underground SDCSs.

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.

The discrete element method coupled with the computational fluid dynamic (CFD-DEM) method is effective for studying the micro-flow process of lignin particles in ceramic membranes. Lignin particles may exhibit various shapes in industry, so it is difficult to model their real shapes in CFD-DEM coupled solutions. Meanwhile, the solution of non-spherical particles requires a very small time-step, which significantly lowers the computational efficiency. Based on this, we proposed a method to simplify the shape of lignin particles into spheres. However, the rolling friction coefficient during the replacement was hard to be obtained. Therefore, the CFD-DEM method was employed to simulate the deposition of lignin particles on a ceramic membrane. Impacts of the rolling friction coefficient on the deposition morphology of the lignin particles were analyzed. The coordination number and porosity of the lignin particles after deposition were calculated, based on which the rolling friction coefficient was calibrated. The results indicated that the deposition morphology, coordination number, and porosity of the lignin particles can be significantly affected by the rolling friction coefficient and slightly influenced by that between the lignin particles and membranes. When the rolling friction coefficient among different particles increased from 0.1 to 3.0, the average coordination number decreased from 3.96 to 2.73, and the porosity increased from 0.65 to 0.73. Besides, when the rolling friction coefficient among the lignin particles was set to 0.6–2.4, the spherical lignin particles could replace the non-spherical particles.

Spring phenology is often considered the start of season (SOS) for vegetation, which can affect ecosystem photosynthesis, respiration, and evapotranspiration. However, the long-run variation of SOS remains unclear at the regional scale. In this research, the long-term variation of SOS in northern China was explored by using the updated normalized difference vegetation index and monthly climatic data during 1982–2014. Furthermore, the relative importance of climatic factors on SOS was analyzed through partial correlation and multivariate regression methods. The main results were as follows: (1) average SOS largely ranged between day 120 and 165 of the year and varied widely for different vegetation types; (2) SOS during 1982–2014 showed an advancing trend, but it appeared to be reversed after 1998; (3) preseason minimum temperature was a dominant factor controlling SOS in most pixels in northern China, followed by maximum temperature (Tmx). However, impacts of radiation and precipitation on the trend of SOS primarily depended on vegetation types; (4) impacts of climatic factors on SOS declined in the period after 1998, especially for Tmx. These findings provide important support for modeling vegetation phenology and growth in northern China.

Pattern structures are usually used to describe the spatial and temporal distribution characteristics of individuals. However, the corresponding relationship between the pattern structure and system robustness is not well understood. In this work, we use geostatistical method–semivariogram to study system robustness for different pattern structures based on three dynamical models in different fields. The results show that the structural ratio of different pattern structures including the mixed state of spot and stripe, cold spot, stripe only, and hot spot are more than 75%, which indicated those patterns all have strong spatial dependence and heterogeneity. It was revealed that the systems corresponding to the mixed state of spot and stripe or cold spot are more robust. This article proposed a method to characterize the robustness of the system corresponding to the pattern structure and also provided a feasible approach for the study of “how structures determine their functions.”

The therapy role of mesenchymal stem cell- (MSC-) derived extracellular vesicles (EVs) in cartilage regeneration has been well studied. Herein, we tried to analyze the role of human umbilical cord MSC- (hUCMSC-) EVs carrying microRNA- (miR-) 181c-5p in repair of cartilage injury. After successful isolation of hUCMSCs, the multidirectional differentiation abilities were analyzed. Then, the EVs were isolated and identified. After coculture of PKH26-labled EVs with bone marrow MSCs (BMSCs), the biological behaviors of which were detected. The relationship between the predicted early posttraumatic osteoarthritis-associated miRNA, miR-181c-5p, and SMAD7 was verified. Gain- and loss-of functions were performed for investing the role of miR-181c-5p and SMAD7 in BMP-induced chondrogenesis in vitro and in vivo. hUCMSC-EVs could be internalized by BMSCs and promote the proliferative, migratory, and chondrogenic differentiation potentials of BMSCs. Additionally, miR-181c-5p could target and inhibit SMAD7 expression to promote the bone morphogenic protein 2- (BMP2-) induced proliferative, migratory, and chondrogenic differentiation potentials of BMSCs. Also, overexpression of SMAD7 inhibited the repairing effect of BMP2, and overexpression of BMP2 and miR-181c-5p further promoted the repair of cartilage injury in vivo. Our present study highlighted the repairing effect of hUCMSC-EVs carrying miR-181c-5p on cartilage injury.

Intensifying global climate change has a significant influence on the vegetation, which is the basis of most of Earth’s ecosystems. It is urgent to identify the critical meteorological elements of vegetation coverage changes to address the problems induced by climate change. Many studies, ranging from theoretical advances to data-driven analyses, have been devoted to investigating meteorological elements’ roles in changing vegetation coverage. However, little has been considered in the aspect of the meteorological elements’ seasonal scale in data-driven studies. Herein, taking China as an example, we collected satellite-derived vegetation coverage data from 2000 to 2020. We then analyzed the meteorological elements, on a seasonal scale, that affect the vegetation coverage change in terms of temperature, precipitation, and solar radiation. We revealed that the critical meteorological elements facilitating vegetation coverage area change differ in both time and space and gave a detailed analysis in line with such findings. Moreover, an apparent seasonal delay effect of meteorological elements on the vegetation coverage change is uncovered.

The key to safe and efficient longwall mining of steeply dipping seams lies in the stability control of the “support-surrounding rock” system. This study analyzes the difficulties encountered when controlling the stability of the support during the longwall mining process of steeply dipping coal seams in terms of the characteristics of the nonuniform filled-in gob using a combination of physical tests, theoretical analyzes, and field measurements. Considering the floor as an elastic foundation, we built a “support-surrounding rock” mechanical model using data obtained on support-surrounding rock systems in different regions and the laws of support motion under different load conditions. Our findings are summarized as follows: first, depending on the angle of the coal seam, the caving gangue rolls (slide) downward along the inclined direction, resulting in the formation of a nonuniform filling zone in the deep gob where the lower, middle, and upper sections are filled, half-filled, and empty, respectively. In addition, an inverted triangular hollow surface is formed on the floor of the gob in the middle and upper sections behind the support. Furthermore, as the angle of the coal seam, length of the working face, and mining height increase, the characteristics of the nonuniform filled-in gob are enhanced. Second, we found that because of the gangue support, the “support-surrounding rock” system is relatively stable in the lower part of the working face; however, in the middle and upper sections of the working face, the contact method and loading characteristics of the support are more complicated, making stability control difficult. Third, the magnitude and direction of the load, action point, and mining height affect the stability of the support to varying degrees, with the tangential load and action position of the roof load having the most significant impacts on the stability of the support. Under loading by the roof, rotation and subsidence of the support inevitably occur, with gradually increasing amplitudes and effects on the intersupport and sliding forces. Finally, we found that overall stability can be achieved by adopting measures involving “sliding advancement of supports” and applying a “down-up” removal order. These research results serve as a significant reference and guidance for longwall mining applications.

Steeply inclined seams buried at dip angles of 35–55° are considered hard-excavated seams in the mining industry. A partial backfilling method based on sub-regional features of surrounding rock deformations and failure and support stability was proposed to realize safe, efficient production, to promote sustainable development of coal mining and disaster prevention in western China. Through experiments, calculations, and theoretical analysis, a mechanical model was established, and governing equations for the deflection curve, bending moment, and rotation were deduced. Results reveal the filling percentage, filling ratio, and working-face dip angle as major factors causing roof failure. The degree of roof deformation decreases with increasing filling percentage, filling ratio, and working-face dip angle. With an increase in filling percentage and filling ratio, the range and magnitude of the stress-concentration zone at a T-junction increase, whereas those pertaining to the stress-release zone in the roof decrease. The stress-arch profile of the roof changes from a single peak to double peaks with reduction arch height. Additionally, the maximum arch height shifts towards the centre with increasing moderation of asymmetric features of stress arches. With an increase in working-face dip angle, stress concentration at the coal-wall head T-junction decreases, and a double-peak stress arch develops. Therefore, in order to obtain the best backfill mining effect, a higher filling percentage is preferred; with a maximum filling value of 0.93, the reasonable range for the filling ratio is 1/3 to 1/2 and the reasonable dip angle of the working face is approximately 35°.

Objectives: Repairing articular cartilage damage is challenging. Clinically, tissue engineering technology is used to induce stem cell differentiation and proliferation on biological scaffolds to repair defective joints. However, no ideal biological scaffolds have been identified. This study investigated the effects of amniotic membrane/collagen scaffolds on the differentiation of adipose-derived stem cells (ADSCs) and articular cartilage repair.Methods: Adipose tissue of New Zealand rabbits was excised, and ADSCs were isolated and induced for differentiation. An articular cartilage defect model was constructed to identify the effect of amniotic membrane/collagen scaffolds on cartilage repair. Cartilage formation was analyzed by imaging and toluene blue staining. Knee joint recovery in rabbits was examined using hematoxylin and eosin, toluidine, safranine, and immunohistochemistry at 12 weeks post-operation. Gene expression was examined using ELISA, RT-PCR, Western blotting, and immunofluorescence.Results: The adipose tissue was effectively differentiated into ADSCs, which further differentiated into chondrogenic, osteogenic, and lipogenic lineages after 3 weeks’ culture in vitro. Compared with platelet-rich plasmon (PRP) scaffolds, the amniotic membrane scaffolds better promoted the growth and differentiation of ADSCs. Additionally, scaffolds containing the PRP and amniotic membrane efficiently enhanced the osteogenic differentiation of ADSCs. The levels of COL1A1, COL2A1, COL10A1, SOX9, and ACAN in ADSCs + amniotic membrane + PRP group were significantly higher than the other groups both in vitro and in vivo. The Wakitani scores of the ADSC + amniotic membrane + PRP group were lower than that in ADSC + PRP (4.4 ± 0.44**), ADSC + amniotic membrane (2.63 ± 0.38**), and control groups (6.733 ± 0.21) at week 12 post-operation. Osteogenesis in rabbits of the ADSC + amniotic membrane + PRP group was significantly upregulated when compared with other groups. Amniotic membranes significantly promoted the expression of cartilage regeneration-related factors (SOX6, SOX9, RUNX2, NKX3-2, MEF2C, and GATA4). The ADSC + PRP + amniotic membrane group exhibited the highest levels of TGF-β, PDGF, and FGF while exhibiting the lowest level of IL-1β, IL6, and TNF-α in articular cavity.Conclusion: Amniotic membrane/collagen combination-based scaffolds promoted the proliferation and cartilage differentiation of ADSCs, and may provide a new treatment paradigm for patients with cartilage injury.

Abstract Background The pro-oncogenic anterior gradient 2 (AGR2) is involved in tumor growth and drug resistance of breast cancer. Mechanisms that regulate expression of AGR2 still need to be elucidated. Methods In this study, expression levels of AGR2 and miR-135b-5p were analyzed in different breast cancer cell lines as well as in clinical breast cancer tissues. The in vitro and in vivo functional effect of AGR2 and miR-135b-5p were also investigated. A luciferase reporter assay was applied to confirm the interaction between miR-135b-5p and AGR2 mRNA. Results We identified AGR2 as a target of miR-135b-5p. Expression of AGR2 was up-regulated in doxorubicin-resistant breast cancer cells. AGR2 mediated doxorubicin-sensitivity of breast cancer cells both in vitro and in vivo. miR-135b-5p negatively regulated AGR2-expression of breast cancer cells increasing doxorubicin-sensitivity. However, miR-135b-5p was down-regulated in doxorubicin-resistant breast cancer cells as well as during treatment with doxorubicin, which might be a probable reason for over-expression of AGR2. Up-regulation of miR-135b-5p increased doxorubicin-sensitivity of breast cancer cells in vivo. In addition, levels of AGR2 negatively correlated with levels of miR-135b-5p in clinical breast cancer tissue samples. Conclusion Our results highlight the potential of miR-135b-5p as a target for treating AGR2-expressing breast cancer with doxorubicin-resistance.

Based on ERA5 from 1980 to 2018, we compare and analyze the trend and interdecadal variation of evaporation anomalies over the tropical Indian Ocean by the evaporation decomposition method. This method mainly decomposes the evaporation anomalies into the Newtonian cooling, stability, relative humidity, wind speed, and transfer coefficient terms. The annual mean evaporation anomalies show an increasing trend (0.083 mm/d/decade). The Newtonian cooling term (0.026 mm/d/decade), the relative humidity term (0.032 mm/d/decade), and the wind speed term (0.026 mm/d/decade) play a major role in the increasing trend. The interdecadal variation of evaporation anomalies shows decreases in the 1980s and after the early 2000s, and an increase in the 1990s. The decreased evaporation anomalies in the 1980s are affected by the transfer coefficient term, which is associated with the North Atlantic Oscillation (NAO). The increased evaporation anomalies in the 1990s and the decreased evaporation anomalies since the early 2000s are largely controlled by the wind speed term, which are dominated by the Atlantic Multidecadal Oscillation (AMO). The Pacific Decadal Oscillation (PDO) may have important impacts on the interdecadal increase of evaporation anomalies by affecting the wind speed in the 1990s.

Hydrogen production from biomass pyrolysis is economically and technologically attractive from the perspectives of energy and the environment. The two-stage catalytic pyrolysis of pine sawdust for hydrogen-rich gas production is investigated using nano-NiO/Al2O3 as the catalyst at high temperatures. The influences of residence time (0–30 s) and catalytic temperature (500–800 °C) on pyrolysis performance are examined in the distribution of pyrolysis products, gas composition, and gas properties. The results show that increasing the residence time decreased the solid and liquid products but increased gas products. Longer residence times could promote tar cracking and gas-phase conversion reactions and improve the syngas yield, H2/CO ratio, and carbon conversion. The nano-NiO/A12O3 exhibits excellent catalytic activity for tar removal, with a tar conversion rate of 93% at 800 °C. The high catalytic temperature could significantly improve H2 and CO yields by enhancing the decomposition of tar and gas-phase reactions between CO2 and CH4. The increasing catalytic temperature increases the dry gas yield and carbon conversion but decreases the H2/CO ratio and low heating value.

The potential of catalytic pyrolysis of biomass for hydrogen and bio-oil production has drawn great attention due to the concern of clean energy utilization and decarbonization. In this paper, the catalytic pyrolysis of pine sawdust with calcined dolomite was carried out in a novel moving bed reactor with a two-stage screw feeder. The effects of pyrolysis temperature (700–900 °C) and catalytic temperature (500–800 °C) on pyrolysis performance were investigated in product distribution, gas composition, and gas properties. The results showed that with the temperature increased, pyrolysis gas yield increased, but the yield of solid and liquid products decreased. With the increase in temperature, the CO and H2 content increased significantly, while the CO2 and CH4 decreased correspondingly. The calcined dolomite can remove the tar by 44% and increased syngas yield by 52.9%. With the increasing catalytic temperature, the catalytic effect of calcined dolomite was also enhanced.

This paper is aimed at the inverted arch support instability of track roadway with mining level +1100 m in Liuyuanzi Coal Mine. By means of field investigation, theoretical analysis, numerical calculation, and engineering practice, the instability reasons of inverted arch structure are expounded, the mechanical mechanism of instability of inverted arch structure is revealed, and the “sliding-rotating beam” for the instability of inverted arch structure is put forward. Based on Fenner’s formula and mechanics principle, the equilibrium equation of “sliding-rotating beam” is given. The results show the following: Firstly, the insufficient stiffness at the joint of the inverted arch structure and the U-shaped steel support on the floor is the key reason for the floor instability. Secondly, when the action stress of the “sliding-rotating beam” is less than the critical value, three kinds of instability modes of the inverted arch structure may occur, that is, sliding upward, rotating upward, or sliding-rotating upward. Each instability criterion and critical value are also different. Considering the axisymmetric condition, the critical value calculation formula of the three modes can be simplified into one formula. Thirdly, the equivalent friction factor restricts the stability of the “sliding-rotating beam,” and there is a “breaking point.” The relationship between the equivalent friction factor and the action stress of the “sliding-rotating beam” is “class hyperbola.” When the equivalent friction factor is greater than the “breaking point value,” the “sliding-rotating beam” may remain stable. Moreover, with the increase of equivalent friction factor, the action stress required for the stability of the “sliding-rotating beam” is smaller, and it tends to be more stable. The breaking point value of equivalent friction factor is 18.6. Finally, 36U-shaped steel round frame with bolt-mesh-shotcrete-combined support is applied to improve the equivalent friction factor and the foot stiffness of U-shaped support in roadway. After two months of on-site implementation, the floor heave was reduced by 69.1%. In conclusion, the theoretical analysis is correct and the control method is effective.

In order to provide a theoretical basis for the design of underground shaft coal pocket and support parameters in coal mines, a mechanical model and a dynamic analysis of the silo wall are established based on the engineering background of Ganhe Coal Mine. The numerical calculation is carried out by using the new model. The back analysis of the silo wall damage in the actual project is carried out, and the deformation law and fracture mechanism of the silo wall affected by different lateral pressure coefficients are analyzed and studied research. Based on the Mohr–Coulomb strength criterion, five sets of orthogonal simulation experiments were carried out for lateral pressure coefficients of 0.6, 0.8, 1.0, 1.2, and 1.4, respectively. The results show that the lateral pressure coefficient is the main factor affecting the deformation of the silo wall, the radial displacement of the silo wall increases gradually with the increase of the lateral pressure coefficient, and the displacement follows the quadratic polynomial function distribution. The maximum tensile stress area of the silo wall is located in the middle and lower part of the shaft coal pocket, which better explains the engineering phenomenon that the actual fracture location of the silo wall is mostly concentrated in the middle and lower part of the underground shaft coal pocket. The targeted repair technology can be used for reference in engineering.

Reticuloendotheliosis virus (REV) is the most frequent exogenous virus that contaminates attenuated vaccines. Therefore, it is extremely important to select REV-free specific-pathogen-free (SPF) chicken embryos. Generally, REV infection is assessed by detecting REV antibodies in SPF chickens. This present study seeks to evaluate REV infection by replacing serum antibody detection with yolk antibody detection. A cohort of 40 nineteen-week-old SPF chickens were artificially inoculated with REV, with 32 SPF chickens raised in another isolation environment served as a blank control. Eggs and serum from 23-week-old chickens were sampled, and yolks were diluted separately to ratios of 1:150, 1:200, 1:300 and 1:400, which were detected together with serum. We found that the yolk antibody detection findings at a dilution of 1:300 had the highest coincidence rate compared with that based on serum antibody measurements. At a dilution ratio of 1:300 for yolk antibody, 72 chickens were continuously observed for 10 weeks from 25- to 34-weeks-old. Our findings were based on serum antibody or yolk antibody detection, and the evaluation results were completely consistent. Therefore, all serum antibody-positive chickens were yolk antibody-positive, and vice versa. Accordingly, vaccine producers can estimate REV cleanliness in a poultry farm by sampling yolk antibody titers.

The artificial-caved rock composited backfilling approach can effectively restrain the dynamic phenomena in the coal seam and the associated roof and floor during mining operations, and can also improve the stability of the system of support and surrounding rock. In this study, based on the analysis of influencing factors affecting the surrounding rock movement and deformation of the composited backfilling longwall face in a steeply dipping coal seam, the roof mechanical model is developed, and the deflection differential equation is derived, to obtain the roof damage structure and the location of the roof fracture for the area without backfilling. The migration law of the roof under different inclination angles, mining depths, working face lengths, and backfilling ratios are analyzed. Finally, mine pressure is detected in the tested working face. Results show that the roof deflection, bending moment, and rotation drop with the increase of the inclination angle and backfilling ratio, whereas these parameters increase with greater mining depth and working face length. The roof failure location moves toward the upper area of the working face as the inclination angle and working face length increases, while it moves toward the center of the non-backfilling area with greater mining depth and backfilling ratio. Results from the proposed mechanical model agree well with the field test results, demonstrating the validity of the model, which can provide theoretical basis for a safe and efficient mining operation in steeply dipping coal seams.

Arsenic trioxide (As2O3), a traditional remedy in Chinese medicine, has been used in acute promyelocytic leukemia (APL) research and clinical treatment. Previous studies have shown that As2O3 exerts its potent antitumor effects in solid tumors by regulating cell proliferation and survival. The aim of this study was to investigate whether As2O3 inhibited gastric cancer cell migration and angiogenesis by regulating FOXO3a expression. We found that As2O3 reduced gastric cancer cell viability in a dose-dependent manner and also inhibited cell migration and angiogenesis in vitro. Western blotting and immunofluorescence showed that As2O3 downregulated the levels of p-AKT, upregulated FOXO3a expression in the nucleus, and attenuated downstream Vascular endothelial growth factor (VEGF) and Matrix metallopeptidase 9 (MMP9) expression. Moreover, we demonstrated that knockdown of FOXO3a significantly reversed the inhibition of As2O3 and promoted cell migration and angiogenesis in vitro. Further, As2O3 significantly inhibited xenograft tumor growth and angiogenesis by upregulating FOXO3a expression in vivo. However, knockdown of FOXO3a attenuated the inhibitory effect of As2O3 in xenograft tumors, and increased microvessel density (MVD) and VEGF expression. Our results demonstrated that As2O3 inhibited migration and angiogenesis of gastric cancer cells by enhancing FOXO3a expression.

Infectious bursal disease virus (IBDV) infection causes immunodeficiency in chickens. To understand cell-mediated immunity during IBDV infection, this study perform a detailed analysis of chicken γc chain (chCD132) and γc family cytokines, including interleukins 2, 4, 7, 9, and 15. The mouse anti-chCD132 monoclonal antibody (mAb) was first generated by the E.coli-expressed γc protein. Immunofluorescence assay further showed that γc was a protein located with the anti-chCD132 mAb on the surface of chicken's splenic mononuclear cells. Real-time quantitative RT-PCR revealed that the chCD132 mRNA transcript was persistently downregulated in embryo fibroblasts, spleen and thymus of chickens infected with IBDV. Correspondingly during IBDV infection, the transcription of five γc family cytokines was downregulated in the thymus and presented an imbalance in the spleen. Fluorescence-activated cell sorting analyses also indicated that the percentage of CD132(+)CD8(+) T cells linearly decreased in the bursa of IBDV-infected chickens. These results confirmed that IBDV infection disturbed the in vivo balance of CD132 and γc family cytokine expression and that IBDV-induced immunodeficiency involved cellular networks related to the γc family.

RUNX3 (runt-related transcription factor-3) is a known tumor suppressor gene which exhibits potent antitumor activity in several carcinomas. However, little is known about the role of RUNX3 in human renal cell carcinoma (RCC). To investigate the clinical relevance of RUNX3 in RCC patients, immunohistochemistry was performed to detect the clinical relevance of RUNX3 in 75 RCC tissues and paired non-cancerous tissues by using tissue microarray (TMA). We also investigated the role of RUNX3 in RCC cell migration, invasion and angiogenesis. The RUNX3 expression was decreased dramatically in human RCC tissue. The RUNX3 expression was significantly correlated with tumor size (P

A new isoflavone, 7,6’-dihydroxy-3’-methoxyisoflavone, has been isolated from the roots of Smilax glabra. The structure was determined by 2D-NMR techniques.