This study aims to effectively solve the problem of destruction coal roof and floor overlying rock after mining protective layer, determines whether gas in protected layer can be released. We do this based on engineering background Weng’an Coal Mine; research analysis movement rocks; evolution cracks pressure relief characteristics layer; through theoretical similar simulation experiments. Through numerical simulation, it was found that depressurized due decompression rate 0.2–0.8. In...

The dimensions of tenons in solid wood furniture significantly influence the mechanical performance mortise and tenon joints. While previous studies have primarily focused on length, width, thickness, they often overlooked impact clearance between tenon. This study investigates effects joints, aiming to enhance their bending moment capacity (BMC) stiffness. A three-factor, three-level orthogonal test was conducted, utilizing range analysis variance assess each factor BMC LSD post hoc...

Landslides have a great impact on the normal traffic of highway, and maintaining highway is foundation economic development, so landslide susceptibility mapping very important. In this study, four counties, which locate in central Ganzi Tibetan Autonomous Prefecture, Sichuan Province, China, are taken as research region. Based 190 historical disaster points region, six factors-elevation, slope, aspect, plan curvature, profile curvature TWI (Topographic Wetness Index) - finally selected for...

In this paper, the elastic properties, chemical bonds, electronic magnetic and phonon spectra of CuNFe3 CuNCo3 synthesized in experiment are calculated by first principles. The results show they ferromagnetic metal compounds with covalent ionic bonds. have large bulk modulus B, Young's Y, shear G, which 191.01 GPa, 202.33 159.65 247.01 58.67 GPa 95.26 respectively, indicates that compressive solid resistance. total moment is 6.96μB, 4.17μB, suggests broad application prospects storage,...

On 21 October 2017, days of heavy rainfall triggered a landslide in Guang’an Village, Wuxi County, Chongqing, China. According to the field investigation after incident, there is still massive accumulation body, which could possibly reactivate landslide. In this study, explore long-term evolution deformation initial Village Landslide, time-series InSAR technique (TS-InSAR) was applied 128 ascending Sentinel-1A datasets spanning from 2017 March 2022. A new approach proposed enhance...

Due to their complex geological structure, it is difficult systematically analyze the surface subsidence of coal mines in southwest China, and factors that cause are also different from other mines. Focusing on problem caused by mining China’s mines, a grade evaluation system for constructed based analytic hierarchy process, ten indicators established perspectives disturbance structure. A matter–element model extension theory cloud then constructed. mine Anshun, Guizhou, taken as an example...

The gas drainage effect is one of the important elements in study coal mines. It critical to establish an effective evaluation model for mines because result directly related safety Through research existing mining process, we discovered that there are few studies on impact deep and soft drainage, methods not sufficiently resolve complex problems arising process drainage. This paper took “three soft” seams Lugou Coal Mine as object constructed index system basis thoroughly analyzing factors...

WuTongZhuang No.182309 mining face is an isolated face. The abutment pressure big and roadway deformation severe due to driving along goaf with short pillar remained. In view of these problems, taking as project background, the law stress distribution was analyzed by use numerical simulation software FLAC 3D field measurement study. results showed that influence scope lead about 55m , peak value 6m ahead concentration factor 3.3.Based on above study results, a scheme advanced support...

Background: Klebsiella pneumoniae (KP) is an important opportunistic pathogen that can easily cause pneumonia and pleural effusion when body resistance reduced. However, the positive rate of KP detected from clinical by traditional methods, including bacterial culture, meager. Therefore, new detection methods are urgently needed to improve other bacteria in effusion. Methods: Simulated fluid infection was first set up. Then circulating cell-free DNA (cfDNA) extracted cultured hydrothorax...

The magnetized water which is used to mix concrete can improve the performance of concrete. This paper presents effect on sprayed in laboratory, also carries out changes dust concentration and rebound rate mixed with mine roadway. results indicate that early strength has been obviously improved be effectively reduced while spraying

In recent years, with the rapid development of equipment manufacturing and advances in research on mine pressure rock mechanics, large-mining-height comprehensive mechanized coal mining technology has become increasingly widely used thick-seam mining. On this basis, because free space extracted is several times that layered mining, occurrence strong ground caused by violent movement basic roof low recovery rate top have main problems. study, Dong Liang Coal Mine was taken as engineering...

After mining, a dynamic distribution of mining fissure elliptic paraboloid zone in the overlying stratum would be formed. Based on rock mechanics, seepage flow mass transfer theory and elastic-plastic theory, coal-rock deformation equation, mixture gas equation diffusion are deduced. Combined with various boundaries, initial conditions, multi-field coupling mathematical model is obtained. The provides theoretical basis for numerical simulation drainage system layout.

Based on the green mining concept of coal mine, connotation and technology system manganese resources were expound. According to problems utilization procedure resources, was suggested. It included water preserving technology, reducing subsidence non-waste as well comprehensive other associated resources. The main key issues in-depth analyzed in this paper, recommendations for further research development proposed.

Abstract Background: Acupoint injection has currently received increasing attention as a treatment for hemiplegia. A number of studies have reported that acupoint some advantages in However, no article summarized the existing evidence. Our study will evaluate efficacy and safety clinical hemiplegia, so it can provide an important reference decision-making. Methods: Randomized controlled trials case control hemiplegia according to included excluded standard were identified searches 6...

Abstract Low-power, small-size, unoccupied devices are often used in the ocean. However, requirements for long-distance operation and long-term, high-power supplies have always been difficult technical problems to solve. Wave energy can be effectively meet of a high power supply. Based on comprehensive analysis shortcomings existing wave converters, we present an innovative design novel hydraulic flexible mobile system its internal structure. The dynamic model is then simplified into...

Brown tide that occurred in Qinhuangdao coastal waters from 2009 to 2015 caused huge losses of local marine aquaculture and tourism, with devastating effects on ecosystems. Nutrients are important biogenic elements for algal growth. It is great significance examine the fluctuation characteristics nutrients process brown understand nutritional mechanism tide. Based survey data 30 stations located area April June 2014, we analyzed nutrient during occurrence its relationship population dynamics...