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The influence of mining factors on seismic activity during longwall mining of a coal seam

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International Journal of mining Science and Technology 2021年第3期31卷 429-437页

作者： Łukasz Wojtecki Joanna Kurzeja Małgorzata Knopik Department of Geology and Geophysics Central Mining Institute40-166 KatowicePoland polish mining group 40-039 KatowicePoland

In this article an attempt to determine the influence of mining factors on the seismic activity during the longwall mining of the upper layer of coal seam no.405/2 in one of the polish hard coal mines in the Upper Silesian Coal Basin was *** longwall panels were mined in analogous geological conditions and based on the same mining system and ***,there was significant difference with regards to the mining factors,which was reflected in the observed seismic *** tools used in mining seismology were applied to illustrate the aforementioned influence of mining factors,*** frequency-energy distribution,the frequency-magnitude distribution,the 2 D distribution of released seismic energy,the relationship between released seismic energy and the volume of mined coal,the Benioff strain release,and the Gutenberg-Richter(GR)b coefficient distribution(b is the proportion between high and low energy tremors).Concerning the Benioff strain release,a new solution,based on the slope of a fitted line in a moving time window,is proposed.

关键词： Underground coal mining Induced seismicity Seismic statistics Benioff strain release

Comprehensive use of the Gutenberg–Richter law and geotomography for improving seismic hazard evaluation in hard coal mines

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International Journal of Coal Science & Technology 2023年第1期10卷 48-59页

作者： Józef Dubiński Krystyna Stec Jacek Krupanek Central mining Institute 40-166 KatowicePoland polish mining group Ltd. Mine MysłowiceWesołaPoland

mining-induced seismicity occurs in numerous underground mines worldwide where extraction is conducted at great depths or in areas characterised by complex tectonic *** is accompanied by rock bursts,which result in the loss of working functionality and the possibility of accidents among *** issue of a constant and reliable seismic hazard evaluation is of key signifcance for both the safety of miners and the stability of *** on its improvement is directed at developing new interpretive solutions and *** nature of the presented solution is the complex interpretation of seismological data that characterise rock mass seismicity and of underground measurement results in the form of a map presenting the longitudinal wave propagation velocity distribution in the rock surrounding the mined coal *** solution was tested in hard coal mines located in the Upper Silesian Coal *** mines are equipped with a modern seismological system enabling the constant monitoring of seismicity together with hazard level evaluation as well as with seismic apparatus for conducting periodic measurements of the seismic wave propagation velocity before the mining *** seismic hazard evaluation criteria were determined based on the obtained results,involving the anomaly of the Gutenberg–Richter law“b”value and the maximum longitudinal seismic wave propagation velocity in the roof *** obtained experience and the result validation of this new comprehensive hazard evaluation method confrm its practical usefulness and indicate the directions of improvement for the solution in question.

关键词： Induced seismicity Rock bursts Mine seismology Gutenberg-Richter law Seismic geotomography

Spatiotemporal analysis of elastic and inelastic deformations in roof-rocks from seismological observations

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International Journal of mining Science and Technology 2021年第2期31卷 241-251页

作者： Maciej JMendecki RafałPakosz Łukasz Wojtecki Wacław MZuberek Faculty of Environmental Sciences the University of Silesia in Katowice41-200 SosnowiecPoland polish mining group 40-039 KatowicePoland Central mining Institute 40-166 KatowicePoland

The spatiotemporal analysis of seismic zones characterised by the scattering and accumulation of strain energy in the roof-rocks of the excavated longwall panel where inelastic or elastic deformations occurred during hard coal seam mining is *** studied longwall panel was designed to utilize the effect of partial stress relaxation caused by the earlier extraction of the coal seams located above.A full seismic moment tensor and spectral source parameter analyses were used to obtain information about the degree of inelastic and elastic coseismic *** study also showed that these deformation changes correspond to variation in the Benioff strain release ***,analyses of deformation zones were compared with the relationship between radiated energy and the excavated volume of rocks per *** concept of balanced seismic energy release assumed the exponential increase of released seismic energy with the increase in the volume of excavated *** between the observed and predicted radiated energies indicated that strain energy in selected zones in the rock mass was either scattered if the prediction was overestimated,or accumulated if ***,the study showed that elastic deformation in one zone can lead to inelastic deformation in the same zone.

关键词： mining seismicity Seismic source volume Apparent volume Hard coal mine Longwall mining Benioff strain

Effects of torpedo blasting on rockburst prevention during deep coal seam mining in the Upper Silesian Coal Basin

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第4期9卷 694-701页

作者： L. Wojtecki P. Konicek J. Schreiber polish mining group Powstanców 30 Katowice 40-039 Poland Department of Geomechanics and mining Research Institute of Geonics Czech Academy of Sciences Studentska 1768 Ostrava-Poruba 708 00 Czech Republic

In the Upper Silesian Coal Basin(USCB),coal seams are exploited under progressively more difficult geological and mining conditions(greater depth,higher horizontal stress,more frequent occurrence of competent rock layers,etc.).mining depth,dislocations and mining remnants in coal seams are the most important factors responsible for the occurrence of rockburst *** mining next to the mining edges of neighbouring coal seams is particularly *** levels of rockburst hazards are minimised via the use of rockburst prevention *** active prevention method is torpedo blasting in roof *** blastings are performed in order to decrease local stress concentrations in rock masses and to fracture the roof rocks to prevent or minimise the impact of high-energy tremors on *** estimation of the effectiveness of torpedo blasting is particularly important when mining is under difficult geological and mining *** blasting is the main form of active rockburst prevention in the assigned colliery in the polish part of the *** effectiveness of blasting can be estimated using the seismic effect method,in which the seismic monitoring data and the mass of explosives are taken into *** seismic effect method was developed in the Czech Republic and is always being used in collieries in the Czech part of the coal ***,this method has been widely adopted for our selected colliery in the polish part of the coal *** effectiveness of torpedo blastings in the faces and galleries of the assigned longwall in coal seam 506 has been *** results show that the effectiveness of torpedo blastings for this longwall was significant in light of the seismic effect method,which corresponds to the in situ *** seismic effect method is regularly applied to estimating the blasting effectiveness in the selected colliery.

关键词： Rockburst prevention Torpedo blasting Seismic effect Upper Silesian Coal Basin(USCB)

Application of long-reach directional drilling boreholes for gas drainage of adjacent seams in coal mines with severe geological conditions

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International Journal of Coal Science & Technology 2022年第6期9卷 75-88页

作者： Grzegorz Lesniak Daniel JBrunner Tomasz Topòr Malgorzata Slota-Valim Renata Cicha-Szot Bartlomiej Jura Jacek Skiba Arnold Przystolik Ben Lyddall Grzegorz Plonka Oil and Gas Institute-National Research Institute Lubicz 25A31-503 KrakówPoland REI Drilling INC.250 West Berger Lane84107 Salt Lake CityUTUSA Central mining Institute 40-166 KatowicePoland polish mining group(PGG) Powstańców 3040-039 KatowicePoland

This study aimed to demonstrate the application of Long Reach Directionally Drilled Boreholes(LRDD)for gas drainage of adjacent seams before and during the longwall face operations of low permeability-high gas content coals Staszic-Wujek Hard Coal Mine in the Upper Silesia Coal Basin(Poland).Five LRDD Boreholes(TM1a-TM5)with a length of 300 and 400 m were located over coal seam 501 in the fractured zone and monitored over six months of longwall face *** Boreholes were combined with Cross-Measured *** characterization and geological modeling supported the results obtained from gas *** drainage efficiency of LRDD Boreholes was the approxi-mately 70%level,while conventional Cross-Measured Boreholes were only 30%.The highest goaf gas quality(94%methane concentration)was reported for TM4,placed at an average elevation of 41 m above coal seam *** highest goaf gas production(average 6.2 m^(3)/min)was reported for LRDD Borehole *** borehole was placed within the fracture zone(average elevation of 24.4 m)and drilled through the sandstone lithotype with the best reservoir properties,enhancing drainage *** Boreholes TM2 and TM4 achieved similar *** three LRDD Boreholes were drilled close to the maximum principal horizontal stress direction,providing borehole stability during *** lowest goaf gas production was reported for LRDD Boreholes TM1a and *** Boreholes were placed in the rubble zone.

关键词： Coal Mine methane Methane control strategy In-seam horizontal boreholes Long reach directionally

Laser-induced white-light emission from graphene ceramics–opening a band gap in graphene

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Light(Science & Applications) 2015年第1期4卷 545-552页

作者： Wieslaw Strek Bartlomiej Cichy Lukasz Radosinski Pawel Gluchowski Lukasz Marciniak Mikolaj Lukaszewicz Dariusz Hreniak polish Academy of Sciences Institute of Low Temperatures and Structural Research50-422 WroclawPoland Wroclaw University of Technology Group of Chemical and Biochemical Processes50-370 WroclawPoland

Recent theoretical and experimental studies have indicated the existence of a new stable phase of carbon with mixed sp^(2) and sp^(3) hybridized bonds—*** a two-layered structure with sp^(2)/sp^(3) bonds may be observed after the photostimulation of highly oriented pyrolytic graphene with femtosecond laser *** hidden multistability of graphene may be used to create a semiconducting phase immersed in the semimetallic continuum,resulting in bandgap *** demonstrate that bandgap opening and light emission from graphene is possible using continuous-wave laser beams with wavelengths from the visible(405 nm)to the near-infrared range(975 nm).We demonstrate that without the application of cooling,the effective temperature of the emitting sample remains lower than 900 K,which is far below the value predicted by the theory of black-body ***,light emission from a graphene sample may be observed at temperatures as low as 10 K.

关键词： ceramics graphene photoluminescence white light

Use of ebselen as a neuroprotective agent in rat spinal cord subjected to traumatic injury

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Neural Regeneration Research 2019年第7期14卷 1255-1261页

作者： Wojciech ?lusarczyk Edyta Olakowska Magdalena Larysz-Brysz Izabella Woszczycka-Korczyńska Daria Gendosz de Carrillo W?adys?aw P.W?glarz Joanna Lewin-Kowalik Wies?aw Marcol Department of Physiology Medical University of Silesia Institute of Nuclear Physics Polish Academy of Sciences

Spinal cord injury(SCI) causes disturbances of motor *** radicals have been shown to be essential for the development of spinal cord *** some progress,until now no effective pharmacological therapies against SCI have been *** purpose of our experiment was to investigate the neuroprotective effects of ebselen on experimental ***-two rats subjected to SCI were randomly subjected to SCI with no further treatment(n = 10) or intragastric administration of ebselen(10 mg/kg) immediately and 24 hours after *** changes were assessed using the Basso,Beattie,and Bresnahan locomotor scale and footprint test during 12 weeks after *** and immunohistochemical analyses of spinal cords and brains were performed at 12 weeks after *** resonance imaging analysis of spinal cords was also performed at 12 weeks after *** treated with ebselen presented only limited neurobehavioral progress as well as reduced spinal cord injuries compared with the control group,namely length of lesions(cysts/scars)visualized histopathologically in the spinal cord sections was less but cavity area was very *** same pattern was found in T2-weighted magnetic resonance images(cavities) and diffusion-weighted images(scars).The number of FluoroGold retrogradely labeled neurons in brain stem and motor cortex was several-fold higher in ebselen-treated rats than in the control *** findings suggest that ebselen has only limited neuroprotective effects on injured spinal *** exprimental procedures were approved by the Local Animal Ethics Committee for Experiments on Animals in Katowice(Katowice,Poland)(approval No.19/2009).

关键词： ebselen antioxidant neuroprotection neuroregeneration spinal cord injury spinal cord repair functional recovery

Polarization effect in tip-enhanced infrared nanospect- roscopy studies of the selective Y5 receptor antagonist Lu AA33810

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Nano Research 2018年第8期11卷 4401-4411页

作者： Natalia Piergies Ewa Pinta Czestawa Paluszkiewicz Helena Domin Wojciech M.Kwiatek Institute of Nuclear Physics Polish Academy of Sciences PL-31342 Krakow Poland Institute of Pharmacology Polish Academy of Sciences Department of Neurobiology 31-343 Krakow Smetna Street 12 Poland Natalia Piergies and Ewa Pieta contributed equally to this work.

A novel approach of combining conventional infrared spectroscopy （IR） and atomic force microscopy （AFM） is presented to better understand the behavior of a drug adsorbed on a metal substrate at the nanoscale level. Tip-enhanced infrared nanospectroscopy （TEIRA） was used for the first time to investigate Lu AA33810, a selective brain-penetrating Y5 receptor antagonist, after immobilization on gold nanopartides （GNPs）. Here, a gold coated AFM tip and gold substrate were used to obtain the near-field electromagnetic field trapping effect. Because of the huge signal enhancement, it was possible to obtain the spectral information regarding the self-assembled monolayer of the investigated molecule. The effect of two orthogonal polarizations （p- and s-polarization modulations） of the excitation laser beam on the spectral patterns is also discussed. The results show that there is a strong relationship between the state of polarization of the incident radiation and the relative infrared band intensities. Another factor affecting the observed spectral differences is the topology of the metal substrate, which may result in the induction of a cross-polarization effect. The performed analysis indicates that the C--C bond from the cyclohexyl group is oriented almost parallel to the metal surface. Conversely, the p- and s-polarized spectral variations suggest that the O=S---O angle is high enough to enable the simultaneous interaction of both oxygen atoms with the GNPs.

关键词： tip-enhanced infrared nanospectroscopy polarization modulation Y5 receptor antagonist gold nanoparticles adsorption

Electromotive force measurements in liquid Ag-In-Pd lead-free alloys

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Rare Metals 2006年第5期25卷 587-591页

作者： Grzegorz Garzet Leszek A.Zabdyr Institute of Metallurgy and Materials Science Polish Academy of SciencesReymonta 2530-059 KrakowPoland

Emf technique was employed to determine indium activities in the liquid Ag-In-Pd alloys using galvanic cells with yttria-stabilised-zirconia as solid electrolyte according to the scheme： kanthal/rhenium, Ag-In-Pd, In2O3 ｜ YSZ ｜ Ni, NiO, Pt. Composition and temperature measurement ranges were limited, because of very steep liquidus surface; 35 compositions for Xpd up to 0.3 were investigated and at temperatures from near-liquidus up to 1700 K. High temperature experiments required special moly furnace to be constructed with unique automatic gas supply system for fumace winding protective atmosphere. Emf readings were taken and recorded by automatic data acquisition system. Linear dependence of emf on temperature was observed for all compositions investigated, and results were approximated by straight line equa- tions. Then In activities were calculated using well-known relations and taking into account correction for thermoelectric power between kanthal and platinum. Results are to be used along with other existing data to perform assessment of the ternary system under accord.

关键词： lead-free solders thermodynamic properties ternary alloy system emf measurement