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In order to study the actual fire-fighting effect of injecting liquid carbon dioxide into the oxidation zone of the goaf area on the 010905 working surface of Wuhushan Coal Mine, surface drilling was designed in the right position of the goaf area at the back of the working face, and liquid carbon dioxide was directly injected into the surface of the oxidized zone of the working face. After a large amount of liquid carbon dioxide was vaporized, the temperature, oxygen concentration and harmful gases were effectively controlled, ensuring the safe mining of the working face. After the liquid carbon dioxide is directly injected into the surface of the borehole, the prearranged beam tube and sensor are used to observe. The results showed that: the temperature and oxygen concentration in the test area showed a linear decline trend, while the CO2 gas concentration showed a sharp rise first and then a continuous decline trend, and the treatment effect was obvious.

Least squares twin support vector machine (LSTSVM) solves two linear programming problems instead of solving complex quadratic programming problems. LSTSVM has the advantages of simple calculation and fast training speed. However, the hyperplanes obtained by LSTSVM are easily affected by outliers and the solution to LSTSVM lacks sparse. To solve this problem, a robust least squares twin support vector machine (R-LSTSVM) based on truncated least squares loss is proposed, and it verifies that the new model is robust to outliers in theory. Furthermore, in order to handle large-scale datasets, a sparse solution to the R-LSTSVM is obtained based on the representation theorem and incomplete Cholesky decomposition, and it proposes a sparse R-LSTSVM algorithm which is suitable for dealing with large-scale datasets with outliers. Numerical experiments show that compared with the existing algorithm, the classification accuracy, sparsity and convergence speed of the new algorithm are improved by 1.97%-37.7%, 26-199 times and 6.6-2 027.4 times, respectively. [ABSTRACT FROM AUTHOR]

Objective: To discuss the effectiveness of Ilizarov technology combined with tarsal V-shape osteotomy for the treatment of traumatic clubfoot., Methods: Between August 2011 and August 2014, 14 patients with traumatic clubfoot were treated. There were 10 males and 4 females, aged 13 to 61 years (mean, 31 years). of 14 cases, 11 had open fractures of the tibia and ankle and 3 had closed fracture of the ankle joint. The interval from trauma to operation was 7-78 months (mean, 36 months). The plantar flexion of the ankle was 44-89° (mean, 57°). After invasive foot soft tissue release and tarsal V-shape osteotomy, the Ilizaroy external fixator with elastic stretching rod was used. At 5-12 weeks after operation, the neutra pos ofthe ankle joint was restored. Then the neutral position of the ankle joint was maintained for 8 to 12 weeks. After removal of external fixator, protective walking brace was used for 8 to 12 weeks., Results: Infection occurred in 9 cases, and was cured after symptomatic treatment. The patients were followed up 10-36 months (mean, 15 months). After treatment, 14 patients had normal appearance of the ankle joint, and X-ray films showed normal structure of the ankle. The ankle dorsal extension was 10° in 9 patients, who had normal walking function; it was 5° in 4 patients, who could walk; in 1 case of neutral position, the foot had no function of up and down stairs. One case had pain during correction because of poor tolerance, and delay traction was given, the function was recovered to normal after active rehabilitation training. According to the International Clubfoot Study Group (ICFSG) score standard, the results were excellent in 9 cases, good in 4 cases, and fair in 1 case; the excellent and good rate was 92.9% at last follow-up., Conclusion: Ilizarov external fixation combined with V-shape osteotomy is effective for the treatment of traumatic clubfoot, with the advantages of less trauma, reliable fixation, satisfactory correction of the deformity, and good function recovery of the ankle.