The Electrostatic Discharge (ESD) is the main cause of some disasters in the mining environments. The ESD depends mainly on the capacitance and resistance of human-body and the capacitance is very sensitive to the environments. In this paper, the figure capacitance of human-body in mining tunnel environment was studied with numerical simulation. It was found that the human-body capacitance in mining tunnel environment depended mainly on the human figure and the shape of the tunnel, only slightly related to the position. The results implied the ESD model was significant in the mining environments; moreover, the human-body capacitance in mining tunnel environment was also approximately linear to the figure size and its value was around 250 pF, which was coincident with Human Body Model (HBM); The figure capacitance was dependent on the constituent of coal layer as well, the typical value of capacitance was 20% larger than that at free space, which meant the mining tunnel was an electrostatic sensitive environment.

Static electricity is one of the reasons for gas explosions in coal mines. When miners leave the narrow tunnel exit of a coal mine, the body voltage may increase by more than ten times with the body capacitance decreasing quickly to 1/10 of its original value, and the body electrostatic discharge (ESD) energy can increase greatly to become a dangerous gas ignition source. In this work, simulation research of human body ESD detonating the gas in a coal mine was conducted. Based on the analysis of the human body electrostatic leakage rules, it is found that electrostatic half-life is mainly relative to the medium resistivity. Therefore it is important to establish a standard for anti-static attire. A series of gas explosion experiments were also conducted by the simulation system, and the results showed that the gas in coal mines might be detonated when the human body capacitance was in the range of 100-1800 pF and the discharge gap between 0.3-1.2 mm. Moreover, gas concentration at approximately 8.5% was most likely to induce an explosion.

Variation of dynamic electrostatic discharge (ESD) on human body that miners’ voltage,capacitance and resistance varies with the body’s dynamic change in coal mine environment is studied. A circuit model of the body’s dynamic ESD in coal mine environment is constructed. The simulation experiment system of the gas detonation by the human body ESD in coal mine is developed successfully. System principle, system hardware design and system software design is expounded. Simulation experiments with different body’s ESD model and the discharge gap has been done. Experimental results show that the system can be carried out series of experiments of the human body ESD model detonating mixed gas, it is concluded that the gas concentration that is the easiest to be detonated is about 8.7%. but not the higher gas concentration is , the more explosive is. The results provide an theoretical and experimental evidence for the safe electrostatic production and management in coal mine Keywords:simulation experiment system; dynamic ESD model ; hardware and software design ; human body capacitance

The human-body capacitor is an important parameter in electrostatic discharging model(ESD).In the tunnel environment,multiple electric-mirror images of dielectric medium were employed,and the human-body capacitors of the system were calculated,based on the uniqueness of electric field solutions.The capacitors' dependence on human-body,tunnel shape,the human-body position in relation to the tunnel,and dielectric constant,was also investigated.The calculations show that the human-body capacitor is very sensitive to the figure of the human-body and the shape of the tunnel,but not closely related to the human-body position in the tunnel.Furthermore,the human-body capacitor depends on the dielectric constant of the environment and the capacitor maximum peak which is 1.15 times than that in free space appears at εr=7(the dielectric constant of dry coal is εr=6.3),which reveals the importance of electrostatic safety in the tunnels of mines.

Gas explosion in coal mine accidents is the most harmful disasters.This paper analyzes the conditions and causes of gas explosion in coal mine,and the human body electrostatic discharge is mainly analyzed,especially analyzes the effection of the dynamic electrostatic discharge on human body of gas explsion.

Human body capacitance of miners decrease quickly to one tenth, body moving voltage increase up to a dozen at narrow exit in coal mine environment, which is a source easy to detonate the gas. The electrostatic half-life is relative with the material resistivity by study electrostatic leakage rules of human body. After a series of experiments of exploding the gas by human body electrostatic discharge simulation, the relationship between different human body capacitance, discharge gap and the gas concentration with exploding are obtained.

Electrostatic discharge (ESD) model on human body has been constructed. “The Experiment Simulation system of ESD model on human body to detonate gas” has been made. The experimental system can measure the gas concentration of explosion and electrostatic potential on human body discharge, resistance and capacitance values in different oxygen concentration and temperature. Measurement accuracy of gas concentration can achieve 0.1 percent in this system. And the most likely to set off gas concentration in coal mine environment can be got, and the results show most likely to detonate the gas concentration was 8.5%, rather than the more easily the higher the concentration of gas detonation. When the human body capacitance is at 1800pF, a sufficient condition will be provided, as long as static voltage of 600V on human body, which can field strength of the breakdown 0.3mm gap in the gas mixture. The academic and experimental evidence can be provided for enacting safety standards for human body electrostatic in coal mine.

The metal lattices are used to replace the conductor cover to screen electromagnetic radiation in actual life.The electromagnetic radiation shielding results of metal lattice by using electromagnetic field theory and numerical calculation method have been investigated.Our results showed that the metal lattice had great shielding effects in the far field zone but would show oscillations and damps in the close field zone whose distance was less than that of metal bars.The results could be used as the guide in electromagnetic radiation shielding design and screening material choosing

Epitaxial La0.7Sr0.3MnO3(LSMO) thin films are fabricated by chemical solution deposition(CSD) method on LaAlO3(100) single crystal substrates.The epitaxy of the films is investigated at different annealed temperature.It shows the epitaxy is better at higher temperature than lower.

The characteristic of electrostatic discharge(ESD) on human body in coal mine environment that miners voltage, capacitance and leakage resistance varies with the body's dynamic change is studied. "The modeling system of the gas detonation by the human body electrostatic discharge in coal mine" is developed successfully, and the body's dynamic ESD model is established. It is concluded that the human body electrostatic discharge can provide more than 22kV/cm breakdown field strength of the mixed gas, and greater than 0.28mJ minimum ignition energy to detonate the gas, and the gas concentration that is the easiest to be detonated is about 8.5%. The results provide an academic and experimental evidence for the safe electrostatic production and management in coal mine.

To research the technology modification for high-polymer material of wind-cone on nano antistatic and fire-retardant performance in coal mine, nano-particles were treated by coupling agent coating, new carbonization, fire-retardant, and toughening technology. The theoretical model of tribology and PTC effect of nano-compounds were studied, the methods of improving the mechanics performance of the material were investigated. The best nano-filling ratio was obtained that the surface resistivity of the material is still less than 106Ω after 70h soaking, the self-extinguishing time is less than 2s, and the smoldering time is zero.

By using electromagnetic field theory and numerical calculation method, the shielding quality of metal grid and mesh on electromagnetic radiation has been investigated. Our results show that the metal grid and mesh have great shielding effects in the far field zone but will show oscillations and damps in the close field zone whose distance is less than that of metal bars. The result can be used as the guide in electromagnetic radiation shielding design and screening material choosing.

This article introduced a method for testing electrostatic discharge energy,the electrostatic spark discharge of high polymer material detonate CS2 and the electrostatic spark discharge on the human body detonate the gas.Some comparison and analysis has been done to provide more information for further test work.

The relation between the conductivity and microstructure in normal rubber and the antistatic composites modified by CB are studied by positron annihilation lifetime spectrum(PALS). Result shows that interlayers will be formed in the composites, it is attributed to the interaction between the nano-CB and rubber chains and is related to the conductivity of composites. At the same time the size of the free volume hole in composites will be decreased. It shows that some small free volume holes will be formed in the composites.

This paper introduces the polymerization technology and principle of general-purpose antistatic agent.The process,the temperature,the vacuum,and the time of reaction influence on polymerization.The material rate influences on the antistatic properties and anti-washing properties.It introduces the modification process of high polymer material and polyester-cotton fabric.After general-purpose antistatic agent dealing with polyester-cotton fabric,surface resistance of polyester-cotton fabric is still 3.1 108Ω and polyester fabric is 5.5×108Ω for 50 standard washing,half-period of the fabricless than0.5s.

This paper has researched the human body dynamic electrostatic discharge model,with various motion and different speed of the actions in different environment·using the simulation device which can replace the narrow mine tunnel,the condition of the different human body static discharge model which is the easiest to detonate the gas is studied.The study results provide an evidence for safe production and management in coal mine.

By analyzing the macro electrical properties and the microscopic structure from SEM of nanomaterials modified mine transmission belt samples. The influences of the filling process of inorganic nano particle-filled rubber and PVC polymer on the physical properties of coal transmission belt is reviewed, as well as PTC and NTC effect on the stability of the physical properties and stability of materials. Influence of nano-materials and polymer materials for rubber and temperature changes in the plastic filled refining process. Crosslinker and major filler changes in the amount and filled plastic chain time on the conductivity of coal conveyer belt is studied. Influence of cure temperature. Cure time on the mechanical performance is studied. The microscopic mechanism of macro conductivity change of conveyer belt is discussed.

In the coal mine environment,static electricity is a potential safety problems,therefore the material used for threading pipe shou'd have a better anti-static properties,and good fire-retardant properties.Using the nano-filler technology,this article carries on the anti-static electricity and the flame-resistant mechanism and the craft discussion of the threading pipe,which is commonly used PVC materials,for coal mine.

The creation mechanism of the human body static electricity and the electrostatic discharge path are inquired into.To reduce the static electricity harm of gas in coal mine,some methods to eliminate the static electricity of human body are introduced.