Contact interaction of double titanium and chromium diboride with Fe-Cr alloys

The kinetics of wetting double titanium and chromium diboride by iron-based alloys with different chromium content is studied. It is shown that contact angles are formed in such systems over the range 0–10°. The energy parameters of wetting are calculated. It is established that chromium as a surface-active element promotes Fe-Cr alloy spreading on the diboride surface. The microstructure of the interaction area is studied. It is shown that terminal solid solutions and eutectics are formed in the TiCrB₂-(Fe-Cr) system. The optimum compositions of the metallic binder are determined for TiCrB₂-based composite materials. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 1–2(453), pp. 109–115, 2007     

小角度控制网的平差方法探讨

本文从改变常规平差元素——角度的观点,阐述了小角度网的平差方法.     

钻削中产生迷切现象的机理研究

随着科学技术的发展．对孔加工精度的要求越来越高．钻削过程中的速切现象对孔加工的形状精度、位置精度有很大的影响．本文用试验、观察、解析的方法分析了钻头迷切现象与各种因素的关系，对提高孔加工精度有了新的揭示．     

凸轮机构推程、回程运动角的最佳匹配及其求解方法

在推程、回程运动角之和 Φ0 +Φ′0 =C(定值 )的情况下 ,必存在某一对推程、回程运动角的最佳匹配 Opti-m um{ Φ0 ,Φ′0 } ;当选用该最佳匹配时 ,对心式直动从动杆盘形凸轮基圆半径 r0 取得最小值 r0 min。本文在揭示出上述事实的基础上 ,研究解决了当选取最佳匹配 Optim um{ Φ0 ,Φ′0 }时 ,按许用压力角 [α]条件求解对心式直动从动杆盘形凸轮基圆半径最小值 r0 min的解析法。     

变角度电子秤在单斗轮取料机上的应用

本文介绍了通过在单斗轮取料机上应用变角度电子秤，实现了一个圆盘准确配加两种以上的原料，避免了原来配加量无法准确控制的问题，提高了配料准确率，混匀料质量明显提高，为降低配矿成本措施的实施提供了技术支持.     

POM晶体倍频相位匹配角的设计及应用

计算了新型有机晶体ＰＯＭ的倍频匹配角，并将ＰＯＭ作为倍频器件用于超短光脉冲的测量中。     

Delaminations at the free edge of a composite laminate

The concept of a fracture process zone where damage takes place is used to analyse the delaminations at the free edges of angle ply laminates under uniaxial tension. The use of a fracture process zone removes the singularity in the interlaminar stresses and enables the initiation and growth of delaminations to be modelled for a perfect laminate without any assumed prior defects. Two different models for the stress displacement relationship in the fracture process zone are examined: a constant stress up to critical displacement and a linear relationship. Finite element analysis shows that there is little difference in the predictions obtained from the two models. An approximate analysis is presented for the constant stress stress-displacement model which is shown to agree with a finite element solution and experimental data. Hence it is argued that the approximate method using a constant stress model for the fracture process zone is sufficient for accurate prediction of delaminations.     

应用于多旋翼MAVs的姿态测量系统

应用一个三轴加速度计、三个单轴角速率陀螺和一个三轴磁强计等微机械惯性传感器,设计廉价轻量姿态测量系统,研究了姿态角推算算法。在以往的姿态测量系统中,陀螺偏差和动加速度的影响限制其应用。将角速度陀螺的误差作为状态量导入到系统,动加速度作为噪音项导入到观测方程中,然后利用扩展卡尔曼滤波器来构成姿态估计算法来降低误差。实际飞行中对比商用高精度传感器和多次室外飞行测试表明,设计的系统能够应于旋翼MAVs。     

Visual recognition efficiency of handheld infrared thermometer interface information under low ambient illuminance

One of the symptoms of plagues, epidemics or pandemics is often a fever, so during such unprecedented times, handheld infrared thermometers are vital devices for monitoring symptomatic individuals. It is therefore very important to enhance reading efficiency when these thermometers are used for lengthy periods of time in a low illuminance environment. The need for the efficient reading of infrared thermometers or a fast reaction time when reading the information is even more relevant now during the COVID-19 pandemic. In this study, a target search experiment of digital characters is carried out through a simulated interface and use scenarios of a handheld thermometer based on three variables: the inclination angle or slant of the seven segment display characters, screen brightness, and ambient illuminance. The experimental results show that the inclination angle or slant of the characters and ambient illuminance have a significant effect on the reaction speed. In general, the slowest reaction time is found when reading characters with a slant of 10° to the left and the reaction time is the fastest with a right slant of 20°. A continued reduction in ambient illuminance does not affect the visual recognition performance but instead further enhances reading efficiency. Increasing the screen brightness increases the reaction time more in relatively low ambient illuminance conditions as opposed to relatively high ambient illuminance, which implies that in higher ambient illuminance conditions, a brighter screen needs to be used to obtain the same reaction speed as that in lower ambient illuminance conditions.