消防战勤保障体系建设的思考

随着经济的发展,消防救援队伍承担的任务越来越繁重.重大灾害事故的发生,对消防战勤保障方面提出了更高的要求.文章主要从消防战勤保障的主要任务职能、消防战勤的任务分类以及消防战勤保障体系建设存在的问题与建议等几个方面进行了详细的阐述,以期消防战勤保障得到更好的发展.     

Simulation studies on a rotating ring disk electrode: Effects of ionic migration with kinetic complication-disk results

In continuation to my previous work (Guha S. AIChE J. 2013;59(4):1390-1399), in this work, effects of ionic migration are evaluated for disk region of a rotating ring disk electrode system by numerically solving complex differential equations, developed for mass transfer along with kinetic complication in presence of ionic migration under limiting current condition. The system for simulation is 0.01 M Fe₂(SO₄)₃ solution with H₂SO₄ as supporting electrolyte. Simulation cases are presence and absence of ionic migration with kinetic complication (oxidation of Fe²⁺ to Fe³⁺ under O₂ pressure). Results show that concentration boundary layer thickness of reactant Fe³⁺ reduces appreciably and steady-state disk current reduces substantially in presence of migration. Simulated steady-state disk current in absence of migration case agrees well with published data. Results indicate higher Fe²⁺ concentration in presence of migration and thereby higher rate of oxidation of Fe²⁺ to Fe³⁺ at all rate constant values.     

沿空切顶成巷段巷道围岩变形规律研究

以宏景塔一矿回采工作面为研究对象,基于切顶卸压无煤柱自动成巷技术原理,采用数值模拟计算和现场实测的方法,对该矿成巷段巷道围岩支承压力分布及围岩变形规律进行分析。研究结果表明:随着工作面向前推进,巷道围岩支承压力呈先增大后减小最后趋于稳定的变化趋势,支承压力稳定值为13.5 MPa;受工作面回采动压的影响,距离工作面70 m以内,锚索受力急剧增大到恒阻值、巷道围岩变形明显;距离工作面70~150 m,锚索受力迅速减小、巷道围岩变形逐渐变缓;在距离工作面150 m之后,锚索受力仅有微量变化、巷道围岩变形趋于稳定。因此确定支护体回撤保守安全位置为工作面后方150 m。工程实践表明:所设支护体回撤距离能够应对巷道围岩变形,成巷效果良好。     

基于流固耦合的柱面气膜密封支撑结构性能研究

利用流固耦合分析方法,研究一种波箔结构柔性支撑柱面气膜密封,探讨气膜厚度、浮环与转子的偏心率以及柔性支撑结构的泊松比、弹性模量、波箔数量等参数对支撑结构等效应力及变形量的影响。结果表明:柔性支承结构满足柱面气膜密封的正常运作,不会造成因为气膜刚度过大而使得浮环与波箔发生破坏性变形,并且变形量远小于波箔高度;柔性支撑的等效应力和变形量随平均气膜厚度的增大而减小,随偏心率的增加而增大,随支撑材料泊松比的增大而增大;弹性模量的增加并不影响柔性支撑结构的等效应力,但是会使变形量减小;增加波箔数量,柔性支撑的等效应力略有减小,变形量显著减小。     

复杂顶板巷道锚杆锚索支护参数优化设计

针对复杂顶板巷道支护难、维修费用高等问题,根据原有支护参数的不足,采用FLAC^3D数值模拟软件,建立分析了复杂顶板巷道数值模型,采用单一变量实验方法,分别以顶板锚杆间排距、长度和帮部锚杆间排距、长度为研究对象,分析了顶板和帮部锚杆和锚索合理支护参数。研究为复杂顶板巷道锚杆锚索支护参数设计提供了理论基础。     

近距离煤层回采巷道支护技术研究

153301工作面受上部3煤和9煤采空区及煤柱影响,巷道围岩变形量大。采用FLAC3D软件分别模拟不同锚杆间距和数量下的巷道围岩变形量,得到锚杆最优支护参数。针对153301工作面巷道采用锚网索和二次注浆加固支护技术,分别设计了不同的支护参数,并对支护后围岩变形量进行监测,监测结果表明围岩变形量和变形速率都有了明显的减小,支护取得了良好的效果。     

复杂松软岩层大断面马头门巷道破坏机理及组合支护技术研究

针对辛置矿马头门巷道断面较大，围岩应力分布复杂，易发生变形破坏的特点，根据现场实际情况，通过理论研究和数值模拟等方法分析了马头门发生破坏失稳的主要原因和锚杆索临时支护作用机理，提出采用主、被动组合支护方式对巷道全断面围岩进行加固和支护，使巷道顶板、两帮和底板加固的围岩形成整体加固拱，提高马头门围岩的承载能力。     

Generation of Cochlear Hair Cells from Sox2 Positive Supporting Cells via DNA Demethylation

Regeneration of auditory hair cells in adult mammals is challenging. It is also difficult to track the sources of regenerated hair cells, especially in vivo. Previous paper found newly generated hair cells in deafened mouse by injecting a DNA methyltransferase inhibitor 5-azacytidine into the inner ear. This paper aims to investigate the cell sources of new hair cells. Transgenic mice with enhanced green fluorescent protein (EGFP) expression controlled by the Sox2 gene were used in the study. A combination of kanamycin and furosemide was applied to deafen adult mice, which received 4 mM 5-azacytidine injection into the inner ear three days later. Mice were followed for 3, 5, 7 and 14 days after surgery to track hair cell regeneration. Immunostaining of Myosin VIIa and EGFP signals were used to track the fate of Sox2-expressing supporting cells. The results show that (i) expression of EGFP in the transgenic mice colocalized the supporting cells in the organ of Corti, and (ii) the cell source of regenerated hair cells following 5-azacytidine treatment may be supporting cells during 5–7 days post 5-azacytidine injection. In conclusion, 5-azacytidine may promote the conversion of supporting cells to hair cells in chemically deafened adult mice.     

三软煤层沿空留巷矿压显现规律研究

为探究沿空留巷矿压显现规律及支护对策，以河南西部典型三软煤层为研究对象，构建了数值分析模型，模拟了工作面前方和后方一定范围内巷道围岩变形和应力变化规律，得到了工作面后方围岩受采动影响大、范围广，顶板下沉现象明显。基于现场实测，得到了顶板下沉量、底板鼓起量、充填体的变形、实煤体变形等随采动影响的变化规律，监测了锚杆的轴向受载情况。研究发现，巷旁膏体充填与巷道内高强锚杆+W型钢带构成的支护体系，较好地解决了三软煤层回采巷道围岩控制问题，为类似开采条件下沿空留巷的实施提供了理论和实践依据。     

基于竹筋-钢筋骨架的人工假顶首层充填厚度研究及现场应用

采用简支梁理论、ANSYS软件数值模拟与现场试验相结合的方法,对竹筋-钢筋骨架人工假顶进行了可行性、受力行为、破坏方式与合理设计参数研究。结果表明,竹筋-钢筋骨架人工假顶结构可有效保护上部充填体,最优充填厚度为4.75 m; 采用竹筋-钢筋配筋方式可兼顾采场稳定性与经济效益,减少支护成本约15%。