Mechanism of rock burst caused by fracture of key strata during irregular working face mining and its prevention methods

To study the occurrence mechanism of rock burst during mining the irregular working face,the study took irregular panel 7447 near fault tectonic as an engineering background.The spatial fracture characteristic of overlying strata was analyzed by Winkler elastic foundation beam theory.Furthermore,the influence law of panel width to suspended width and limit breaking span of key strata were also analyzed by thin plate theory.Through micro-seismic monitoring,theoretical analysis,numerical simulation and working resistance of support of field measurement,this study investigated the fracture characteristic of overlying strata and mechanism of rock burst in irregular working face.The results show that the fracture characteristic of overlying strata shows a spatial trapezoid structure,with the main roof being as an undersurface.The fracture form changes from vertical‘‘O-X"type to transverse‘‘O-X"type with the increase of trapezoidal height.From the narrow mining face to the wide mining face,the suspended width of key strata is greater than its limit breaking width,and a strong dynamic load is produced by the fracture of key strata.The numerical simulation and micro-seismic monitoring results show that the initial fracture position of key strata is close to tailgate 7447.Also there is a high static load caused by fault tectonic.The dynamic and static combined load induce rock burst.Accordingly,a cooperative control technology was proposed,which can weaken dynamic load by hard roof directional hydraulic fracture and enhance surrounding rock by supporting system.

Eight Key Words about Internet in the Government Work Report

In the government work report for Two Sessions 2019, key words about E-commerce and internet were mentioned lots of times. This included terms such as Internet+, cross-border E-commerce,industrial internet, digital economy,sharing economy, online and offline consumption, Internet+education and soon.Keywords No.1:Internet+Work Report:1. Internet+was advanced across the board and new technologies and models were used to transform traditional industries. 2. We will speed up efforts to pursue Internet+in all industries and sectors.

How to Interpret a Piano Work--Research Processing and Teaching Guidance of New Works

In the process of piano teaching,it is the basic working ability of piano teachers to independently study and process works and guide students.In the face of a strange work,the piano teacher should first conduct a comprehensive analysis and research of the work,and then can reasonably guide the students.Starting from three aspects of work research,performance design,and key points of attention,this paper expounds the ways and steps of work research and processing in order to help the piano teachers to expand their teaching repertoire.

Newly Established Key Laboratories at CAS

By employing network-based observation techniques, field experimental methods and ecological information technology, the Lab is designed to explore the coupling between carbon, water and nutrient cycles within an ecosystem and its underlying mechanisms, to integrate and model ecosystem patterns and processes at multiple spatiotemporal scales, and to comprehensively study the relationship between ecosystem management and sustainable development. Its major focuses are：

Physical Location of HelminthosporiumCarbonum Susceptibility Gene hm1 by FISH of a RFLP Marker umc119 in Maize

A fluorescencein situ hybridization (FISH) procedure was adopted to physically map a RFLP marker, umc119 near the centromere of the long arm of linkage group1 in maize. The hm1 gene (Helminthosporium carbonum susceptibility gene) was linked closely with the marker umc119. RFLP markers are very good landmarks for mapping genes. Therefore, we also determined the position of the gene hm1 on the chromosome based on the physical location of umc119. The disease induced by infection ofHelminthosporium carbonum is one of the serious maize diseases and it distributes in many countries including China. Hybridization sites were showed on 1 L (long arm of chromosome1) and 5 L. The percentage distance from centromere to the hybridization site was 22.86 on 1 L and 58.23 on 5 L the detection rate was about 12% for mitotic cells. In interphase nuclei five hybridized sites were detected. It demonstrated that umc119 was multiplicated sequences. FISH has more advantages overin situ hybridization (ISH) detected by DAB for increasing the detection ratio and contrast between chromosomes and hybridization signals. The ability to detect the hybridization signal of a small low copy DNA sequence is a very important key towards wide application of FISH for plant genome mapping.

Comparative Analysis of Human Resource Develop- ment between Different Countries under the Vision of Competition

Based on a literature review from English language journals related to the field of human resource development(HRD),the conceptual framework for this study was derived from the models developed by American Society for Training and Development(ASTD)for HRD practice.This study compared and analyzed the similarities and differences in HRD roles,key work dimensions,and practitioner competencies through the competitive vision of different countries,including China,US,UK,Germany,Japan,India,Singapore,and Korea.This comparative study not only described the HRD position of Chinese enterprises under the international HRD coordinates but also indicated how these differences inspire HRD in China.