异螺距万分尺设计

介绍了一种螺旋万分尺的结构设计。该万分尺的微分筒采用双螺纹,两螺纹的螺旋方向相同,螺距不同。采用V型槽和V型块精确定位来增加量程。测量最小刻度可达0.001 mm,读数精度达0.0001 mm。万分尺采用纯机械结构,结构原理简单,制造安装方便。     

不同煤层掘进工作面瞬变电磁法探测应用研究

煤矿井下瞬变电磁法成为煤矿井下超前探测工作的重要手段，在矿井水害预测预报上发挥着很大的作用。随着矿井上组煤层资源的逐渐枯竭，煤矿开采资源逐渐延伸向下组煤层。同一井田范围内同煤层及其顶底板的岩性特征一般相差不大，瞬变电磁法在同煤层施工过程中接收到的物理背景场较为接近；而不同煤层及其顶底板岩性特征通常会有较大的差别，瞬变电磁法在不同煤层施工过程中会接收到差别较大的物理背景场。当矿井存在多煤层开采时，通过大量数据研究瞬变电磁法在不同煤层巷道探测中的响应特征规律，分析并掌握不同煤层条件对瞬变电磁法探测结果的影响，能够提高瞬变电磁法在多煤层探测成果的准确性。     

Experimental investigation of different morphology textured ceramic tools by in-situ formed for the dry cutting

Surface texture is considered an important measure to improve the cutting performance of a tool. In this study, we have prepared three types of textured and conventional tools on the rake face by an in-situ formed method. During the experiment, the best parameters of three types of textured tools were selected for dry cutting AISI 1045 steel at different cutting speeds. Cutting forces, cutting temperatures, workpiece surface roughness, and tool wear were measured during the cutting process. The results showed that textured tools have significantly reduced cutting force, cutting temperature, and tool wear, and the roughness of the workpiece was improved compared with the conventional tool. The micro-pit texture tool has less stress contact region than the micro-groove width texture tool, but the micro-groove width texture tool exhibiting the best cutting performance. This investigation clearly showed that the textured tool prepared by the in-situ formed method has improved cutting performance.     

适应不同重力环境的仿壁虎机器人运动仿真

针对不同重力环境下仿壁虎机器人的运动稳定性、运动高效协调性等问题,基于四足机器人的步态规划现状和仿壁虎机器人自身特定的机械结构,设计了仿壁虎机器人在g、0、-g 3种环境下的足端轨迹和运动步态。在ADAMS仿真软件中研究了机器人的运动学和动力学特性,得到了仿壁虎机器人稳定爬行与脚掌黏附力、足端轨迹和运动步态的关系。探讨了仿真结果的合理性和局限性,为仿壁虎机器人在实际环境中的稳定运动奠定了理论基础。     

Indirect adaptive control of nonlinear system via dynamic multilayer neural networks with multi‐time scales

This paper deals with adaptive nonlinear identification and trajectory tracking problem via dynamic multilayer neural network with different time scales. By means of a Lyapunov‐like analysis, we determine stability conditions for the on‐line identification. Then, a sliding mode controller is designed for trajectory tracking with consideration of the modeling error and disturbance. The main contributions of the paper lie in the following aspects. First, we extend our prior identification results of single‐layer dynamic neural networks with multi‐time scales to those of multilayer case. Second, the e‐modification in standard use in adaptive control is introduced in the on‐line update laws to guarantee bounded weights and bounded identification errors. Third, the potential singularity problem in controller design is solved by using new update laws for the NN weights so that the control signal is guaranteed bounded. The stability of proposed controller is proved by using Lyapunov function. Simulation results demonstrate the effectiveness of the proposed algorithm. Copyright © 2014 John Wiley & Sons, Ltd.     

沉积型铝土矿高效回采工艺

基于孝义铝矿沉积型矿体特点及赋存条件,通过不同采矿工艺的对比,分析了液压反铲回采铝土矿的功效,证实了液压反铲对沉积型铝土矿回采具有高回收率、低贫化率等优点.该工艺对于缓倾斜薄矿体铝土矿、铁矿露天开采具有重要意义.     

霍林河煤田一号露天矿煤层显微煤岩特征

文中应用煤岩学方法 ,对霍林河煤田具代表性的 17号煤层的显微煤岩特征进行了系统研究 ,阐述了不同组分分布特征及其变化规律 ,并指出了煤的加工利用方向     

松软厚煤层回采工作面前方煤体不同分层应力变化特征的数值模拟

应用ANSYS软件建立了松软厚煤层回采工作面前方煤体力学几何模型,分析了沿回采方向煤体顶、底分层的水平、垂直和剪切应力变化特征及其差异性;并通过与我国煤矿常见煤岩抗压、抗剪强度特征的对比分析,分别探讨了煤体不同分层应力变化特征对其破坏裂隙程度的影响。所得结论可指导针对松软厚煤层回采工作面前方不同距离、不同分层煤体制定有效、可行的"卸压增透"技术措施,并为进一步探讨松软低透气性厚煤层瓦斯抽采理论提供新的思路和方法。     

西山煤田不同变质程度煤孔隙结构分形特征及影响因素研究

为研究煤的多孔介质属性及其分形特征,以山西沁水盆地西山煤田为研究对象,采用扫描电镜(SEM)分析了煤表面孔隙结构特征。基于SEM图片,通过盒维数法计算得到了不同煤样表面孔隙分形维数,并分析了其影响因素。研究结果表明:煤表面具有显著的分形特征,分形理论能够较好地描述煤孔隙结构复杂程度;在本测试煤样中,不同煤样分形维数值在1.33～1.92范围内变化;变质程度、水分、埋深、坚固性系数(f值)对煤孔隙分形维数有显著影响,随Ro和埋深的增加煤体表面孔隙趋于复杂化,分形维数值不断增大;而水分和灰分的存在使得煤体表面变得相对光滑,能够减小分形维数值。分形维数是衡量煤孔隙复杂程度的有效参数,在煤矿现场瓦斯防治中,对于具有高分形维数的煤体,应该引起重视。这类煤体往往破坏程度较高,具有强吸附性,孔隙连通性差,瓦斯抽采困难,在煤炭开采过程中,容易导致煤与瓦斯突出、瓦斯涌出等灾害。     

谈浮选回路设计中的几个问题

根据生产实践,对浮选工艺流程设计中经常遇到的几个问题药剂添加的地点及方式,有用矿物的分速浮选,浮选"短路”的问题及磨矿回路中采用选别工艺的情况提出了看法.