河北宣龙铁矿地质特征及开采问题

河北宣龙铁矿是我国重要的沉积型铁矿,了解其地质特征能够给铁矿开采中存在的问题提供参考处理意见。本文对宣龙铁矿成矿时区域地质背景、含矿层位和成矿地质年代、全球环境进行研究,并结合对鲕状赤铁矿和叠层石赤铁矿结构特征、地球化学特征和沉积环境的分析,可知宣龙铁矿形成于障壁海岸环境中的障壁岛临滨环境,深海中的Fe2+在铁细菌和蓝细菌共同作用下在宣化-龙关一带富集成矿。宣龙铁矿的地质特征与铁矿开采过程中采矿点分散、开采经济效益低、铁矿回采率低和环境保护等问题关系密切。     

CHINA＇S RECENT DEVELOPMENT IN COAL MINING,PROCESSING AND UTILIZATION

This paper describes the state-of-the-art and outlook of coal mining and clean coal echnology in China. As the major mining method,underground mining accounts for 96% of the total production. Among the state own mines, the percentage of mechanized mining reached 71%. A rapid development of high-productive and high-profitable mines,especially those with longwall sublevel caving method, is described. The issues of heavy duty equipment, roof bolting, mine safety are also addressed. The Chinese government is paying more and more attention on the environmental problems inducing from coal mining,processing and utilization. A basic framework of clean coal technology is being formed and a wide range of technology is included.     

《施工技术》20/2018 不同种类粗纤维混凝土基本力学性能及弯曲韧性试验研究

正选取钢纤维、聚乙烯醇纤维和聚丙烯纤维3种粗纤维,研究不同粗纤维在不同体积掺量条件下(0%,0.5%,1%,1.5%,2%)对混凝土抗压强度、劈拉强度和弯曲韧性的影响,并分析粗纤维对上述指标的影响机理。结果表明:不同种类粗纤维对混凝土抗压强度无显著影响。端部弯折钢纤维和经表面处理的聚丙烯粗纤维在体积掺     

液压支架双伸缩立柱的流固耦合分析研究

根据我国煤炭行业的最新标准,通过建立双伸缩立柱的模型,研究了立柱的强度计算方法,并通过有限元分析软件分别对立柱进行无液和有液情况下2倍中心载荷的强度分析。结论认为,有限元分析结果与理论计算基本一致。通过对比有流体时立柱的受力状况,显示了流固耦合对立柱的影响,可为液压支架设计提供一定的参考价值。     

某在役航油管道阴极保护追加及排流防护技术应用

本文对某在役航油管网的阴极保护缺陷和地铁对管网的杂散电流干扰进行了介绍,在进行现场检测的基础之上,提出了管网阴极保护的追加改造方案和地铁杂散电流干扰的排流措施。     

Simultaneous Determination of Trace Lead and Chromium in Water Using Laser-Induced Breakdown Spectroscopy and Paper Substrate

Toxic metals such as lead and chromium in aqueous solutions have been analyzed simultaneously by laser-induced breakdown spectroscopy(LIBS), in which the ordinary printing paper is used as a liquid absorber which was immerged into Pb(NO3)2and Cr(NO3)3aqueous solution to enrich the heavy metals. This method overcomes the drawbacks of splashing and low sensitivity in ordinary LIBS analysis of water, in which a laser beam is directly focused on a liquid surface. A good signal intensity and reproducibility has been demonstrated. The Pb 405.78 nm and Cr 427.48 nm spectral lines are used as the analytical lines. The variation of line intensity with immersion time was investigated. The calibration curve for quantitative measurement of Pb and Cr in water was established, and the detection limits are 0.033 mg/L and 0.026 mg/L respectively,which is about 2-3 orders of magnitude better than that in the ordinary LIBS analysis of heavy metal in solution.     

基于支反力的轴承套圈外圆磨削力测量方法

提出了一种基于支反力的轴承套圈外圆磨削力测量方法,在电磁无心夹具前后2个支点上分别安装测力传感器,测量砂轮与套圈接触前后平衡状态下的支承力,建立磨削前后受力平衡方程并推导了套圈磨削时承受的法向和切向磨削力计算公式.随后,根据实测工件轴及砂轮轴的电流、电压和转速确定支承力的变化范围,反推了测力传感器的选定方案并给出了详细...     

一种钎焊Si3N4陶瓷的高温非晶钎料

(专利申请号:201010167495.9,专利公开号:CN101823188A)1技术领域此发明属于钎焊材料技术领域。涉及一种钎焊Si3N4陶瓷的高温非晶钎料,更具体地说是涉及一种Ti-Zr-Cu-B高温活性非晶钎料。2背景技术Si3N4陶瓷是一种很有前途的工程结构陶瓷材料,     

有机共混结构太阳电池的稳定性

有机共混结构太阳电池由于质轻、价廉、柔性,受到人们的广泛关注。随着有机共混结构太阳电池的能量转换效率的不断提高,其性能的稳定性也受到人们的重视。文中从太阳光、空气中的氧气和水分等因素对有机共混结构太阳电池的电极、活性层等的作用来说明这些因素对有机共混结构太阳电池稳定性的影响,阐述了影响有机太阳电池稳定性的原因,提出了解决有机共混结构太阳电池稳定性的方法,为高性能、高稳定性的有机共混结构太阳电池的研究提供有价值的参考。     

改性废聚氨酯制备高分子膨胀型阻燃剂

以废聚氨酯(PU)、三氯氧磷(POCl3)等为原料合成了二氯磷酰化聚氨酯(PDP),再将PDP与三聚氰胺(MEL)等反应,制备了高分子膨胀型改性聚氨酯阻燃剂(MPU)。通过红外光谱(FTIR)分析、扫描电镜-能谱分析(SEM-EDS)、热重分析(TGA)等手段对产物进行了表征。将所得MPU用于环氧树脂(EP)的阻燃,并采用极限氧指数法(LOI)、垂直燃烧法(VBT)等方法检测了EP/MPU复合材料的阻燃性能。结果表明:当以1,4-二氧六环为溶剂、PU浓度为20 g/L、POCl3浓度为400 g/L、反应温度为80℃、反应时间为13 h时,PDP的P含量可达到19.6%;当MPU含量为30%时,EP/MPU复合材料的LOI值为28%,阻燃等级可达到UL 94V-0级。