Investigations of water inrushes from aquifers under coal seams

In many coal mines, limestone-confined aquifers underlie coal seams. During coal extraction from these mines, water inrushes occur frequently with disastrous consequences. This paper introduces the hydrogeological conditions of the coal mines and the potential water inrush disasters from aquifers under coal seams. It then presents the water inrush mechanism. The main factors which control water inrushes include strata pressure, mining size, geologic structures and the water pressure in the underlying aquifer. Analysis shows that reduction of confinement due to mining is the major cause of the water-conducting failure in the floor strata. The depth of the failure zone is strongly dependent on the mining width. This paper also presents field observation results of the water-conducting failure in the floor strata, and applies the finite element method coupled with stress-dependent permeability to analyze hydraulic conductivity enhancement due to coal extraction. Finally, theoretical and empirical methods to predict water inrushes are given, and technical measures for improving mine design and safety for coal extraction over aquifers are presented. These measures include fault and fracture grouting and mining method modification such as changing long-wall to short-wall mining.     

坚持科学发展观开拓创新求发展——庆祝水利部河北河北省水利水电勘测设计研究院成立50周年

2006年金秋时节,河北院迎来了建院50周年华诞.50年的光辉历程,是奋斗拼搏、开拓创新的50年,是河北水利史上丰碑永存的50年.     

Structural transformation of FePt nanocomposite films during annealing and its effects on magnetic properties

Fe100-xPtx(x=30at.%-60at.% ) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction shows that the FePt nanocomposite films undergo a phase transformation from a disordered FCC phase to an ordered L10 phase between 673 and 773 K. The coercivity is 306 kA·m-1 whiles the average grain sizes is about 10 nm in the optimized FePt alloy film sample annealed at 673K. The adjustable coercivity and fine grain size suggest that this FePt nanocomposites system is suitable as recording media at extremely high areal density.     

生物质合成气一步法合成二甲醚的研究

用共沉淀沉积法制备了生物质合成气直接合成二甲醚(DME)的催化剂,考察了固定床中温度、压力、空速等工艺条件对二甲醚合成性能的影响,同时基于Gibbs自由能最小法对合成DIME反应的化学平衡进行模拟计算,并与实际测试结果相比较.结果表明,模拟结果与测试结果吻合较好.     

工程项目投标报价中的风险分析

针对目前国内的招投标制度和方法,投标报价风险成为企业能否中标的最大风险,报价在招标中占的分数权重在40%~60%之间,对能否中标起到决定性的作用。从总承包商自身能力及有意识行为、总承包模式3个方面对工程项目中的投标报价风险进行了分析。     

高可靠性烧结金属丝网防爆元件的应用研究

烧结金属多孔元件作为隔爆元件的应用，很好地满足了火焰过滤元件的性能要求，进一步拓宽了烧结金属多孔元件的应用领域，章在论述其性能特点、结构类型的同时，对其在微孔结构设计上的差异也进行了描述。     

SIMADYN D控制器在武钢热轧动态无功补偿系统中的应用

SIMADYN D控制器应用于动态无功补偿，标志武钢动态无功补偿控制实现数字化突破。提高了系统的可靠性、调节精度和动态指标。     

苯并口恶嗪-环氧化合物-胺类催化剂体系开环聚合反应的研究

采用TLC，GPC，1H－NMR及IR等分析方法，对苯并恶嗪－环氧化合物－胺类催化剂体系的聚合反应进行了研究，表征了产物结构，并探讨了聚合反应机理，结果表明，苯并恶唪－环氧化合物体系在胺类催化剂如苄胺，咪唑的作用下，能发生开环聚合反应，生成低分子量的聚合物。     

SMSBR处理焦化废水的污泥特性

采用一体化膜—序批式生物反应器 (SMSBR)处理焦化废水 ,在泥龄为 6 0 0d的状态下运行 ,污泥产量少并体现出延时曝气的特征 ,平均污泥负荷 <0 .10 2kgCOD (kgMLSS·d)。当污泥浓度 >6 5 18mg L时污泥沉降性能变差 ,但以膜实现泥水分离可以保证出水不受之影响。VSS SS(比活性 )总体呈较弱的下降趋势 ,但脱氢酶活性的变化与出水COD的对应关系出现了反常现象。经过长期运行 ,污泥颗粒平均粒径从 10 0 μm降至 30 μm ,并在低温和高负荷的情况下表现出分散生长的特点 ,从而使上清液的浊度和COD升高。     

-50℃用20MnMoD钢锻件及其焊接接头性能

研究了-50℃的20MnMoD钢锻件及其焊接接头在不同热处理状态时的综合力学性能。结果表明,-50℃的20MnMoD钢锻件具有良好的低温韧性,可与-50℃级正火型低温压力容器钢15MnNiNbDR配套使用。