Research on Prevention of Rock Burst with Relieving Shot in Roof

AbstractDuring hard roof rupture or slip instability with the sudden release of large amount of elastic energy, rock burst will be caused by violent shock easily. Based on the geological conditions of 6303 working face in Jisan Colliery, numerical simulation was carried out systematically of relieving shot in roof, then the reasonable parameters of relieving shot was provided. The results of danger-breaking measures of relieving shot in roof on-site shows that the danger of rock burst is reduced with fractured circle connected and values of electromagnetic emission and drillings decreased

Dynamic Evaluation and Analysis of Regional Innovation Capability in Eastern China from the Perspective of High-quality Development

Abstract The economy of China has turned to the stage of high-quality development. In this sense, the connotation of regional innovation capacity should reflect more aspects, such as better economic effectiveness, people-centered philosophy of development and better living conditions. This study aims at establishing the evaluation index system of regional innovation capacity under high-quality perspective. Then the dynamic evaluation method based on gray correlation degree and TOPSIS is improved. And the improved method is applied to evaluate the regional innovation capacity under high-quality development perspective. The results show that: 1) The regional innovation capacity of Jiangsu, Zhejiang, Shanghai and Guangdong under high-quality development perspective is better than other regions, while the regional innovation capacity of Beijing-Tianjin-Hebei is imbalanced. Regional innovation capability of Fujian, Shandong, and Hainan from a high-quality perspective is at the middle and lower levels. 2) From the perspective of development trends, the gap of regional innovation capacity between Beijing, Jiangsu, Zhejiang, Shanghai, Guangdong and Fujian, Hebei, Shandong is gradually narrowing. 3) An in-depth analysis of the regional innovation capability of the eastern provinces and cities from the perspective of high-quality development through different dimensions shows that Beijing, Guang-dong, Jiangsu perform well in all dimensions, while Fujian and Hainan need to pay more attention to innovation input and the creation of a better innovation environment to enhance innovation output and promote innovation effectiveness. At last, based on above analysis, relevant policy recommendations are proposed.</jats:p

Dynamic and static load effect of non-uniformly “bow-shaped” super-thick key strata

The rupture of super-thick key strata is a crucial factor in triggering mine dynamic disasters. Investigating the impact of their non-uniform thickness on mining-induced stress environments and rupture dynamic loads, and further revealing the mechanism of dynamic and static loading on rock burst pressure, is the theoretical foundation for predicting rock burst risks and disaster prevention and control. This paper investigates the non-uniformly thick “bow-shaped” super-thick key strata in the Binchang mining area of Shaanxi. Through comprehensive theoretical analysis and numerical simulation, it analyzes the mechanical principle of abnormal stress concentration in the coal rock mass beneath the “bow-shaped” super-thick key strata, clarifies the influence of the “bow-shaped” morphology on the rupture characteristics of the super-thick key strata and reveals the mechanism of dynamic and static load superposition in the area beneath the “bow-shaped” formation, leading to rock bursts. Based on the study above, a method for predicting the disaster risks caused by the rupture of “bow-shaped” super-thick key strata is proposed. The results show that in the convex area under the “bow-shaped” formation of the super-thick key strata, the high stress is exceptionally concentrated, increasing the coal rock body stress by an additional 22.1 MPa, with an increase rate of up to 56%, which is the fundamental reason for the high static load formation in the underlying coal-rock body. At the same time, the principal stress in the concave area of the “bow-shaped” formation concentrates and undergoes significant deformation, increasing the risk of strong dynamic loads due to rupture. Under the combined action of dynamic and static loads in the non-uniformly thick “bow-shaped” super-thick key strata, the rock bursts are likely to occur in the pillar and roadway areas. The proposed method for predicting the disaster risks due to the rupture of “bow-shaped” super-thick key strata effectively guides the disaster prevention and control in high-risk mining areas prone to rock bursts. Additionally, the distributed fiber optic field measurement results validate the intrinsic connection between the rupture of super-thick key strata and the generation of dynamic loads

N-acetyl glucosamine improves intestinal mucosal barrier function in rat

Our study investigated the effect of N-acetylglucosamine (GlcNAc) on the intestinal mucosal barrier function in rats. Rats were randomly assigned into normal control group, diarrhea-predominant irritable bowel syndrome (IBS-D) group and GlcNAc group. IBS-D was introduced into the IBS-D group without any treatment. The GlcNAc group were treated with GlcNAc. Microvilli and tight junctions of intestinal epithelial cells were detected. The D-lactic acid level and diamine oxidase (DAO) activity in the serum were determined. Compared with normal rats, microvilli were sparsely distributed on the intestinal epithelial cells, the tight junction gap also widened, and D-lactic acid level and DAO activity were significantly higher in the IBS-D group. After GlcNAc treatment, the microscopic structure of the intestinal mucosa became largely normal, and the level of D-lactic acid and the DAO activity were lowered. In conclusion, GlcNAc can effectively improve the intestinal mucosal barrier dysfunction, perhaps through enhancing the cellular metabolism

Application of high-pressure water jet technology and the theory of rock burst control in roadway

This paper puts forward using high-pressure water jet technology to control rock burst in roadway, and analyzes the theory of controlling rock burst in roadway by the weak structure zone model. The weak structure zone is formed by using high-pressure water jet to cut the coal wall in a continuous and rotational way. In order to study the influence law of weak structure zone in surrounding rock, this paper numerically analyzed the influence law of weak structure zone, and the disturbance law of coal wall and floor under dynamic and static combined load. The results show that when the distance between high-pressure water jet drillings is 3 m and the diameter of drilling is 300 mm, continuous stress superposition zone can be formed. The weak structure zone can transfer and reduce the concentrated static load in surrounding rock, and then form distressed zone. The longer the high-pressure water jet drilling is, the larger the distressed zone is. The stress change and displacement change of non-distressed zone in coal wall and floor are significantly greater than that of distressed zone under dynamic and static combined load. And it shows that the distressed zone can effectively control rock burst in roadway under dynamic and static combined load. High-pressure water jet technology was applied in the haulage gate of 250203 working face in Yanbei Coal Mine, and had gained good effect. The study conclusions provide theoretical foundation and a new guidance for controlling rock burst in roadway. Keywords: High-pressure water jet technology, Rock burst, Weak structure zone, Dynamic and static combined loa

Simultaneous Determination of Night Effective Constituents and Correlation Analysis of Multiconstituents and Antiplatelet Aggregation Bioactivity In Vitro in Chuanxiong Rhizoma Subjected to Different Decoction Times

Several effective constituents, such as vanillin, ferulic acid, senkyunolide I, senkyunolide H, coniferyl ferulate, Z-ligustilide, butylphthalide, senkyunolide A, and levistilide A, are unstable and possess mutual transformation relationships in Chuanxiong Rhizoma (CR). Traditional Chinese medicine mainly involves decoction, and the content of effective constituents and antiplatelet aggregation bioactivity (AAB) in CR may vary with different decoction time (10 min, 20 min, 30 min, 40 min, 50 min, and 60 min). Here, we showed that coniferyl ferulate and levistilide A were detected in CR material, but not in the decoction. The effective components possessed transformation and degradation in CR decoction of different times. The effective components and the strength of AAB at 10 and 20 minutes were the strongest, followed by 30–50 minutes, and 60 minutes were the weakest by analysis of SIMCA-PLS in CR decoction of different times. In the Pearson correlation analysis, there were correlations (P<0.05) between effective components, which were ferulic acid and senkyunolide I (coefficient was 0.976), ferulic acid and senkyunolide H (coefficient was 0.972), senkyunolide I and senkyunolide H (coefficient was 0.982), senkyunolide A and butylphthalide (coefficient was 0.974), senkyunolide A and Z-ligustilide (coefficient was 0.947), and butylphthalide and Z-ligustilide (coefficient was 0.993). Effective components (ferulic acid, senkyunolide I, and senkyunolide H) and AAB were correlated and the Pearson correlation coefficients were respectively 0.965, 0.973, and 0.999. In the stepwise regression analysis, senkyunolide H and senkyunolide I were correlated with AAB (P<0.05). Senkyunolide H (H) was positively correlated with AAB, senkyunolide I (I) was negatively correlated with AAB, and its expression was AAB = 1.187 ∗ H − 0.199 ∗ I − 0.422. These findings indicate that there are some correlations between effective components and AAB in CR

Simultaneous Determination of Night Effective Constituents and Correlation Analysis of Multiconstituents and Antiplatelet Aggregation Bioactivity <i>In Vitro</i> in Chuanxiong Rhizoma Subjected to Different Decoction Times

Several effective constituents, such as vanillin, ferulic acid, senkyunolide I, senkyunolide H, coniferyl ferulate, Z-ligustilide, butylphthalide, senkyunolide A, and levistilide A, are unstable and possess mutual transformation relationships in Chuanxiong Rhizoma (CR). Traditional Chinese medicine mainly involves decoction, and the content of effective constituents and antiplatelet aggregation bioactivity (AAB) in CR may vary with different decoction time (10 min, 20 min, 30 min, 40 min, 50 min, and 60 min). Here, we showed that coniferyl ferulate and levistilide A were detected in CR material, but not in the decoction. The effective components possessed transformation and degradation in CR decoction of different times. The effective components and the strength of AAB at 10 and 20 minutes were the strongest, followed by 30–50 minutes, and 60 minutes were the weakest by analysis of SIMCA-PLS in CR decoction of different times. In the Pearson correlation analysis, there were correlations (P&lt;0.05) between effective components, which were ferulic acid and senkyunolide I (coefficient was 0.976), ferulic acid and senkyunolide H (coefficient was 0.972), senkyunolide I and senkyunolide H (coefficient was 0.982), senkyunolide A and butylphthalide (coefficient was 0.974), senkyunolide A and Z-ligustilide (coefficient was 0.947), and butylphthalide and Z-ligustilide (coefficient was 0.993). Effective components (ferulic acid, senkyunolide I, and senkyunolide H) and AAB were correlated and the Pearson correlation coefficients were respectively 0.965, 0.973, and 0.999. In the stepwise regression analysis, senkyunolide H and senkyunolide I were correlated with AAB (P&lt;0.05). Senkyunolide H (H) was positively correlated with AAB, senkyunolide I (I) was negatively correlated with AAB, and its expression was AAB = 1.187 ∗ H − 0.199 ∗ I − 0.422. These findings indicate that there are some correlations between effective components and AAB in CR.</jats:p