Chip geometries during high-speed machining for orthogonal cutting conditions

The originality of this work consists in taking photographs of chips during the cutting process for a large range of speeds. Contrary to methods usually used such as the quick stop in which root chips are analyzed after an abrupt interruption of the cutting, the proposed process photographs the chip geometry during its elaboration. An original device reproducing perfectly orthogonal cutting conditions is used because it allows a good accessibility to the zone of machining and reduces considerably the vibrations found in conventional machining tests. A large range of cutting velocities is investigated (from 17 to 60 m/s) for a middle hard steel (French Standards XC18). The experimental measures of the root chip geometry, more specifically the tool-chip contact length and the shear angle, are obtained from an analysis of the pictures obtained with a numerical high-speed camera. These geometrical characteristics of chips are studied for various cutting speeds, at the three rake angles −5, 0, +5° and for different depths of cut reaching 0.65 mm.     

一种改进编码器角度解算过程的方法与实现

在机械电子一直是一个热门学科,其目的是通过软件控制机械操作来代替机械的哑巴解决方案。DS-25旋转电子编码器能够很好地与机械电子应用相匹配,其输出为两路标准的sine和cosine曲线,通过分析sine和cosine数值来计算编码器所对应的绝对角度位置。通过对DS-25的工作模式分析和实际应用情况提出角度解算的改进方案,该方案利用DS-25工作于粗略模式下测试到的角度值来推算精确模式下的信号周期,结合精确模式下测试到的角度值来计算编码器所对应的绝对角度。摒弃其原有的复杂查表过程进而节省电子表格的存储空间,在降低硬件成本的同时提升了软件灵活性。实验证明,算法的改进能够节省约2KB的存储空间,角度位置误差能控制在1‰以内。     

从社会管理角度来看设计——在现代设计史里去找答案

长期以来,有很多学者都对设计做了很多重要的研究,并得到了丰富的理论成果。但是设计是一个很难说得明明白白的词,其内在的含义却需要不断的挖掘,如其内在所含的管理属性就需要我们去做一个探究,本文从历史的、客观的角度对设计的管理层面进行了探讨。     

0.618法最优确定盘状摆动凸轮机构的最小基圆半径

在满足机构许用压力角条件下,采用０．６１８法最优确定盘状摆动凸轮机械的最小基圆半径。     

Model test of helical angle effect on coal loading performance of shear drum

The work presented in this paper focuses on improving coal loading performance of shear drum.Employing the similarity theory,we carried out a dimensional analysis of the correlation parameters which in...     

Deformation effect of lateral roof roadway in close coal seams after repeated mining

This paper analyzed the deformation mechanism in lateral roof roadway of the Ding Wu-3 roadway which was disturbed by repeated mining of close coal seams Wu-8 and Wu-10 in Pingdingshan No. 1 Mine. To determine the strata disturbance scope, the strata displacement angle was used to calculate the protection pillar width. A numerical model was built considering the field geological conditions. In simulation, the mining stress borderline was defined as the contour where the induced stress is 1.5 times of the original stress. Simulation results show the mining stress borderline of the lateral roadway extended 91.7 m outward after repeated mining. Then the original stress increased, deforming the roadway of interest. This deformation agreed with the in situ observations. Moreover, the strata displacement angle changed due to repeated mining. Therefore, reselection of the displacement angle was required to design the protective pillar width. Since a constant strata displacement angle was used in traditional design, the proposed method was beneficial in field cases.     

Assurance of uniformity of measurements of spectral and dispersion characteristics in fiber-optic information transmission systems with wavelength-division multiplexing

The state and problems involved in achieving the uniformity of measurements in the field of fiber-optic information transmission systems and their components are considered. Possible approaches to the solution of these problems and the basic methods and techniques that have been developed in Russia up to this point are analyzed. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 30–34, May, 2006.     

基于屏栅电离室的双参数谱仪研制及其应用

以屏栅电离室为基础，同时引出其阳级和阴极信号，研制了1台能够同时记录两路信号的双参数谱仪，在DEC－3000工作站上编制程序，实现了双维谱数据的获取、显示和存储。利用所建立的谱仪，测量了α放射源的双维谱，计算了α粒子的角分布，并讨论了如何利用角分布来校正活度测量中自吸收和反散射的影响以及改善电离室阳极能谱的能量分辨率。     

Measurement methods for LCoS displays

Abstract— Two measurement methods to characterize uniformity and the absolute cell gap of LCoS images will be reviewed. These are simple to use in a production environment and have allowed major improvements in manufacture to be achieved. For the purpose of this paper, the liquid‐crystal mode used is the 45° normally black mode.     

圆柱体质心测量中转角取值分析

为获得质量非均匀圆柱体质心的三维坐标，测量时需使圆柱体转过一定的角度。分析表明，转角最好取为90度以获得最佳测量效果。如果受条件限制，宜在45度到90度之间选取，尽量避免取小于30度的值。