一种移动式辅助装卸搬运工具的设计研制

介绍了物流装卸搬运作业中一种装卸方法,阐述了该方法配套装备的设计特点。     

锅炉受热面抗振隔板的计算

从锅炉受热面管道振动的原因出发,提出加装抗振隔板是消除振动最有效的方法,并给出抗振隔板选取方法及其结构和安装方法,最后给出抗振隔板及悬吊所用材料的选取。     

Effects of roller burnishing process parameters on surface roughness of A356/5%SIC composite using response surface methodology

In this study, a simple roller burnishing tool was made to operate burnishing processes on A356/5%SIC metal matrix composite fabricated by electromagnetic stir casting under different parameters. The effects of burnishing speed, burnishing force and number of burnishing passes on the surface roughness and tribological properties were measured. Scanning electron microscopy （SEM） graphs of the machined surface with PCD （insert-10） tool and roller burnished surface with tungsten carbide （WC） roller were taken into consider- ation to observe the surface finish of metal matrix composites. The mechanical properties （tensile strength, hardness, duc- tility） of A356/5%SIC metal matrix composites were studied for both unburnished samples and burnished samples. The results revealed that the roller burnished samples of A356/ 5%SIC led to the improvement in tensile strength, hardness and ductility. In order to find out the effects of roller bur- nishing process parameters on the surface roughness of A356/ 5%SIC metal matrix composite, response surface methodol- ogy （RSM） （Box-Behnken design） was used and a prediction model was developed relevant to average surface roughness using experimental data. In the range of process parameters, the result shows that roller burnishing speed increases, and surface roughness decreases, but on the other hand roller burnishing force and number of passes increase, and surface roughness increases. Optimum values of burnishing speed （1.5 m/s）, burnishing force （50 N） and number of passes （2） during roller burnishing of A356/5%SIC metal matrix com- posite to minimize the surface roughness （predicted 1.232 μm） have been found out. There was only 5.03% error in the experimental and modeled results of surface roughness.     

水溶性酚醛树脂改性离合器摩擦材料的制备与性能研究

分别采用水溶性酚醛树脂法、浸浆缠绕法和贴胶缠绕法3种工艺制备了汽车用离合器面片,研究了3种工艺对离合器面片的摩擦磨损性能、物理性能和力学性能的影响。结果表明：采用水溶性酚醛树脂工艺制备的离合器面片耐热性好,摩擦系数大小适中、热稳定性好,磨损率低,硬度、孔隙率适中,而且剪切强度和断裂应变最大,综合性能最为优异。     

The Meaning of Surface Structure and Deep Structure to Translation

Surface structure and deep structure first come up with by Chomsky is an innovative action in linguistics. Despite the arguments involved around surface structure and deep structure, it is instructiona...     

狭长深基坑开挖引起的地表沉降变形及影响因素分析

狭长深基坑的开挖会对周边环境产生较大影响。鉴于此,文章基于有限元软件MIDAS GTS建立三维模型,重点分析基坑开挖过程中周围地表沉降的发展规律,并将数值模拟结果与施工现场监测数据进行对比,结果表明二者数据吻合良好。在此基础上对狭长深基坑开挖引起的地表沉降变形的影响因素进行分析,结果表明:基坑周围地表沉降值对基坑开挖深度敏感,且随着基坑开挖深度的增加而逐渐增大;地表最大沉降值出现在离墙后约8 m的位置,地表沉降的主要影响范围为0.5He~1.5He;增大地连墙厚度和嵌入深度、减小内支撑水平和竖向间距均使地表沉降值呈现减小趋势。     

钢管高性能混凝土界面黏结性能试验

为研究钢管高性能混凝土界面黏结性能,进行了包括钢管壁厚、截面形式、钢材类型和钢管内表面状态4 个参数的推出试验研究,分析了试件的试验现象、荷载-滑移曲线和界面黏结强度。 结果表明,仅当试件壁厚较薄时,钢管中下部会出现45°剪切滑移线;不同钢管壁厚试件的荷载-滑移曲线共有3 种增长模式,均包括胶结滑移段、滑移段和摩阻段3 个阶段;增大钢管壁厚、使钢管内表面锈蚀可以提高界面黏结强度;采用方形钢管代替圆形钢管、不锈钢管代替普通钢管对界面黏结强度有不利影响。     

用向量函数求解曲线积分和曲面积分

为了方便计算曲线积分和曲面积分,利用向量函数表示空间曲线和空间曲面,给出计算第一类曲线积分和第一类曲面积分的两个定理,并给予详细证明;最后,通过实例分析,说明其应用方法。     

Effects of condensed water on limestone surfaces in a marine environment

We have evaluated the effects of condensed water on limestone surfaces through a procedure that foresaw the cooling of the samples before their exposition to the open air, so that the condensation phenomena could occur easily. The effects of the condensed water were evaluated by measuring the weight change of the samples, through SEM observations and analysis of the 3-D profile, using laser profilometer. The results show the weak action of condensed water on the stone surface, particularly if compared with that of rain.     

速度攀岩运动员肌肉疲劳的表面肌电信号分析方法

实验表明,速度攀岩运动是非周期性运动,攀岩运动员在速度攀岩的每趟或同一趟的不同时段,他的表面肌电信号都有较大的变化,是显著的非稳定信号。所以,运用表面肌电信号分析速度攀岩运动员的肌肉疲劳问题存在着一定的困难:不能用传统的频阈分析方法去评价相关肌肉的疲劳问题,而只有运用非线性信号分析方法才能较好解决这一问题,然而sEMG非线性信号分析的应用尚属初期探索阶段,有待科研工作者的深入研究。