RESUMO
Microseismic monitoring systems (MMS) have become increasingly crucial in detecting tremors in coal mining. Microseismic sensors (MS), integral components of MMS, profoundly influence positioning accuracy and energy calculations. Hence, calibrating these sensors holds immense importance. To bridge the research gap in MS calibration, this study conducted a systematic investigation. The main conclusions are as follows: based on calibration tests on 102 old MS using the CS18VLF vibration table, it became evident that certain long-used MS in coal mines exhibited significant deviations in frequency and amplitude measurements, indicating sensor failure. Three important calibration indexes, frequency deviation, amplitude deviation, and amplitude linearity are proposed to assess the performance of MS. By comparing the index of old and new MS, critical threshold values were established to evaluate sensor effectiveness. A well-functioning MS exhibits an absolute frequency deviation below 5%, an absolute amplitude deviation within 55%, and amplitude linearity surpassing 0.95. In normal operations, the frequency deviation of MS is significantly smaller than the amplitude deviation. Simplified waveform analysis has unveiled a linear connection between amplitude deviation and localization results. An analysis of the Gutenberg-Richter microseismic energy calculation formula found that the microseismic energy calculation is influenced by both the localization result and amplitude deviation, making it challenging to pinpoint the exact impact of amplitude deviation on microseismic energy. Reliable MS, as well as a robust MS, serve as the fundamental cornerstone for acquiring dependable microseismic data and are essential prerequisites for subsequent microseismic data mining. The insights and findings presented here provide valuable guidance for future MS calibration endeavors and ultimately can guarantee the dependability of microseismic data.
RESUMO
A novel three-dimensional multi-level porous g-C3N4 modified MXene-derived TiO2@C aerogel (g-C3N4/TiO2@C aerogel) was synthesized for NO removal. Through SEM analysis, 2D g-C3N4 and 2D Ti3C2 nanosheets were constructed into an interconnected macroscopic framework with continuous macropores via ice template. OD TiO2 nanoparticles uniformly covered 2D C nanosheets with irregular mesopores and macropores in in-situ oxidation of Ti3C2 nanosheets by calcination via TEM analysis. g-C3N4/TiO2@C aerogel for photocatalytic activation of hydrogen peroxide (H2O2) had an excellent efficiency of 90.7% for NO removal at parts per million level. This efficiency was 4.9 times and 7.8 times that of g-C3N4/TiO2@C aerogel and H2O2 individually, due to the synergy between photocatalysis and H2O2 oxidation. Meantime, g-C3N4/TiO2@C aerogel exhibited an enhanced performance compared with g-C3N4 nanosheet (55.7%) and TiO2@C aerogel (38.5%). It was attributed to the large specific surface area (93.82 m2/g) with hierarchical mesoporous and macroporous structure and the 2D/OD/2D heterojunction of g-C3N4/TiO2@C aerogel, further enhancing electron-hole separation. The mechanism was hypothesized that g-C3N4/TiO2@C aerogel activated H2O2 to generate hydroxyl radicals (·OH) and superoxide radicals (·O2-) for oxidation of NO.
Assuntos
Peróxido de Hidrogênio , Luz , Catálise , Porosidade , TitânioRESUMO
OBJECTIVE: To understand the epidemic situation of schistosomiasis in 27 counties (cities, districts) that reached the criteria of schistosomiasis infection controlled in Anhui Province. METHODS: According to the requirement of The National Assessment Scheme of Schistosomiasis, 81 administrative villages where the schistosomiasis epidemic situation was relatively heaver in above-mentioned 27 counties (1 village per town, 3 towns per county) were sampled and investigated. RESULTS: From 2012 to 2014, 81 villages were investigated, and 34,293 residents received the serum examinations, and 1,086 were positive with a positive rate of 3.17% (0.65%-9.58%), and the positives received stool examinations and the average stool positive rate was 0.37% (0-4.0%). The calculated prevalence of human infection was 0.01%. A total of 3 057 domestic animals were investigated including 438 cattle, 2,550 sheep, and 69 other animals, and no infections were detected. A total of 11,261 living Oncomelania hupensis snails were collected and detected, but no schistosome infected snails were found. Before this investigation, no infected snails were detected for more than 2 years [average 2.3 (2-6) years], and no acute schistosome infection cases were found for more than 2 years [average 4.9 (2-9) years]. CONCLUSION: The infection rates of schistosomiasis in residents and domestic animals are relatively low, and no schistosome infected snails are found in the regions.
