Study on Spontaneous Combustion "Three Zones" of the Distribution Law and Integrated Fire Prevention Technology in Mined-Out Area of Lingquan Mine.

To determine the risk range of remaining coal in the goaf of the higher slice on the seventh mining and fifth face of Lingquan Mine, the beam tube monitoring system was adopted to supervise the temperature and gas content changes in the goaf during the normal mining period of the working face. As per the principle of dividing spontaneous combustion "three zones" (SCTZ), numerical simulation of the distribution of SCTZ in the goaf of the work face was performed. The O2 content and index gas in the goaf were measured and analyzed, and combined with the in-situ measurement outcomes, the distribution of SCTZ in the goaf was determined through the FLUENT numerical modeling program. The outcomes show that the distribution pattern of SCTZ in the goaf of fully mechanized mining face is: the heat dissipation zone is 0-41 m, the oxidation zone is 41-97 m, the suffocation zone is more than 97 m away from the work face, and the increment of temperature is 0.7/°C. Based on the judgement result of SCTZ, the minimum recovery rate of work face is above 3.7 m/d. The use of new polymer materials validly solves the problem of excessive CO in the return air corner of the goaf and prevents self-ignition accidents in the goaf.

Risk identification of coal spontaneous combustion based on COWA modified G1 combination weighting cloud model.

To realize the scientific judgment of spontaneous combustion risk in the coal mine, the spontaneous combustion influence factors were analyzed from the three aspects of coal spontaneous combustion tendency, air leakage, and oxygen supply, heat storage and heat dissipation. And the basis for the evaluation of t spontaneous combustion grade was constructed. Combination ordered weighted averaging (COWA) calculation was introduced to optimizes G1 subjective weighting, and a COWA modified G1 combined weighting cloud model was proposed to identify the spontaneous combustion risk in the coal mine. Finally, the rationality of the model was verified with actual cases. The research results show that the spontaneous combustion risk level in the Lingquan coal mine is relatively safe, which is consistent with the actual situation. And the spontaneous combustion tendency of coal is the leading factor affecting spontaneous combustion risk.

Complementary coding optical stealth transmission based on amplified spontaneous emission light source.

Complementary encoder of stealth signal is proposed and demonstrated for coding, modulating and enhancing the privacy of optical stealth transmission. With complementary encoding, the stealth signal carried by amplified spontaneous emission (ASE) light keeps the same characteristic to ASE noise and can be concealed well under public channel. The experiment results demonstrate the feasibility of the scheme and show the stealth signal has the same impact on public channel in transmission performance, compared to the ASE noise.