Coal and gas outburst dynamic system

Coal and gas outburst is an extremely complex dynamic disaster in coal mine production process which will damage casualties and equipment facilities, and disorder the ventilation system by suddenly ejecting a great amount of coal and gas into roadway or working face. This paper analyzed the interaction among the three essential elements of coal and gas outburst dynamic system. A stress-seepage-damage coupling model was established which can be used to simulate the evolution of the dynamical system, and then the size scale of coal and gas outburst dynamical system was investigated. Results show that the dynam- ical system is consisted of three essential elements, coal-gas medium （material basis）, geology dynamic environment （internal motivation） and mining disturbance （external motivation）. On the case of CI 3 coal seam in Panyi Mine, the dynamical system exists in the range of 8-12 m in front of advancing face. The size scale will be larger where there are large geologic structures. This research plays an important guid- ing role for developing measures of coal and gas outburst prediction and prevention.

The Study on the Sports Injuries and Psychological Stress of Chinese Elite Players

Through national gymnastics to 30 active athletes and 30 national women＇s handball training athletes, which results in the paper are as follows： outstanding gymnastics. The main part of injury is elbow, ankle, and the degree of damage to elbow as the worst. Women＇s handball player injury occurred campaign main pan is knees joint, ankle, with the most serious level of knee injuries. Outstanding women athletes in gymnastics and handball injury occurred campaign＇s state anxiety level is higher, were reached 49.37 ± 94 and 49. 00 ±61.3, excellent gymnast sports injury of the main source of stress for coach criticism, leading opponent table Now when the good. Good men＇s gymnastics athlete sports injury of main source of stress for physical or psychological made a mistake, coach criticism, suffered severe pain or injury After. Outstanding female handball player of the main source of the sports injury stress for the referee injustice, not the bad climate space equipment and error, etc. 4, excellent gymnastics The main way to deal with the players face for attributed to the outside world not controllable factors, focus your attention on the action or distracting, excellent handball in the athletes to diversify To strengthen the way to deal with the game for faith, quickly forget unhappy experience and experience of stress take more carefully way. The abstract should summarize the contents of the paper and should contain at least 70 and at most 150 words. It should be set in 9-point font size and should be inset 1.0 cm from the fight and left margins. There should be two blank （10-point） lines before and aiter the abstract. This document is in the required format.

Study on the Safety of Physical Education in Colleges and Universities

This paper uses survey research methods to research the three factors affecting sports teaching safety and management in the colleges and universities. It proposed to increase the awareness of the safety of teachers and students. And it should have a rational organization of teaching. It also should increase financial input on a regular basis in the field and equipment maintenance. Specialized security agencies and establish safety management systems and contingency plans, to encourage students to participate in accident insurance, guarantee learning the sports teaching activities of the security.

Apoptosis induced by NaYF_4:Eu^(3+) nanoparticles in liver cells via mitochondria damage dependent pathway

As lanthanide-doped sodium yttrium flouride(NaYF_4)nanoparticles have great potential inbiomedical applications,their biosafety is important and has attracted significant attention.In the present work,three different sized NaYF_4:Eu^(3+)nanoparticles have been prepared.Liver BRL 3 A cell was used as a cell model to evaluate their biological effects.Cell viability and apoptosis assays were used to confirm the cytotoxicity induced by NaYF_4:Eu^(3+)NPs.Apart from the elevated malondialdehyde(MDA),the decrease of superoxide dismutase(SOD),glutathione peroxidase(GSH-PX)and catalase(CAT)activity indicated reactive oxygen species(ROS)generation,which were associated with oxidative damage.The decrease of mitochondrial membrane potential(MMP)value demonstrated the occurrence of mitochondria damage.Then,release of cytochrome c from mitochondria and activation of caspase-3 confirmed that NaYF_4:Eu^(3+)NPs induced apoptosis was mitochondria damage-dependent.