胶辊前冲工艺改善成纱质量的探讨

为了稳定和提高成纱质量，针对气动加压和弹簧加压的细纱机，采取增加前胶辊前冲量和增大胶辊直径的工艺措施，对不同品种进行了纺纱试验。试验结果表明，合理选用胶辊前冲量，优化纺纱工艺，可以提高成纱务干质量，同时胶辊采用大的前冲量后，胶辊直径从32.5mm用30．3mm后可再连续使用到27mm，胶辊的使用寿命可提高一倍，从而降低了胶辊的消耗成本。     

大直径深盲孔难加工材料加工方法研究

分析了深盲孔加工难点,针对大直径深盲孔难加工材料的特点,阐述了套料加工对于大直径深孔加工是一种高效率、低成本的加工方法.通过实例分析套料加工工艺及套料刀、切断刀设计的要点.采取相应的控制措施,实现了难加工材料大直径深盲孔的高效加工.该加工方法具有一定的通用性.     

Oxidation characteristics of Si0.85Ge0.15 nanowires

Oxidation characteristics of Si_0.85Ge_0.15 nanowires were investigated using transmission electron microscopy (TEM) analyses. Si_0.85Ge_0.15 nanowires were grown in a tube furnace by vapor–liquid–solid (VLS) method and thermally oxidized at 925 °C for 1–8 h. After oxidation, oxide thicknesses were measured using TEM images. Si_0.85Ge_0.15 nanowires showed a thicker oxide than Si nanowires, for the whole range of oxidation time. The oxidation rate of Si_0.85Ge_0.15 nanowires significantly decreased in nanowires with diameters less than 150 nm. Long-term oxidation in Si_0.85Ge_0.15 nanowire resulted in the oxidation of germanium atoms.     

一种高效射流曝气器设计研究

实验表明喷嘴直径与喉管距离之比值在0.5～0.8间最优;喉径与喷嘴直径比值在0.33～0.50间最优;喉管长度影响不大;喷嘴面积与喉管面积比在0.36～0.64间曝气效果最好。同时结果表明射流曝气器在农村一体化设备曝气系统中具有良好利用前景。     

Numerical and experimental study on hollow-cone fuel spray of highpressure swirl injector under high ambient pressure condition

A hybrid breakup model was proposed as a trustworthy prediction of hollow-cone fuel spray in the present study and the atomization process of the hollow-cone fuel spray of a high-pressure swirl injector in a Gasoline Direct Injection (GDI) engine under high ambient pressure conditions was studied by a new hybrid breakup model. The proposed hybrid breakup model is composed of the Linearized Instability Sheet Atomization (LISA) model as a primary breakup process. The Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model, instead of the Taylor Analogy Breakup (TAB) model, was used as a secondary breakup process. The effects of the droplet deformation on a droplet aerodynamic external force are considered in the APTAB model. In addition, we replaced the x ² distribution function used in previous the APTAB model by the Rosin-Rammler distribution function to improve the prediction precision. The Laser Induced Exciplex Fluorescence (LIEF) technique and the Phase Doppler Anemometry (PDA) system were used to produce a set of experimental data for the model validation. The estimation of the prediction ability of the LISA+APTAB model was carried out, and spray characteristics, which are difficult to obtain by experimental method, were calculated and discussed. The suggested hybrid breakup model showed better prediction capability compared with the previous model (LISA+TAB model). From the calculated results, the effect of the ambient pressure on the SMD (Sauter Mean Diameter) and droplet velocity could be discussed quantitatively.     

方腔内带双圆柱体自然对流三维计算研究

基于计算流体力学理论,采用有限体积法建立辐射模型,对长、宽、高均为5m 的方腔内带双圆柱体进行了三维计算研究。分析了腔内双圆柱体中心轴线间距、管径以及方腔的左壁面温度和右壁面温度对腔内沿Z轴各截面的平均温度分布的影响。研究结果表明,双圆柱体中心轴线间距越大,在腔的左右壁面处对流强度越强;双圆柱体管径越大,对流强度越弱;左壁面温度越高,对流强度越弱;右壁面温度越高,自然对流越强烈。该结果可为试验研究提供一定的参考。     

谐波分析在轮毂质量分类判定中的应用

介绍了谐波分析法的原理,阐述了谐波分析法在汽车轮毂跳动量检测及分类判定中的应用。通过傅里叶变换,计算出了谐波的幅值和初始相位,使相位按照特定的步长从0°变化到360°,画出了谐波波形。通过傅里叶变换将离散的数据分解成周期性的谐波数据,增强了采用谐波分析法检测轮毂质量的直观性。     

舰载型拦阻装置拦阻性能分析

为得到舰载型拦阻装置的性能及设计方法,分析了拦阻装置的组成及工作方式,建立了舰载型拦阻装置的动力学模型,给出了飞机航向拦阻力方程。计算得到了定长冲跑条件下,不同质量飞机拦阻时定长冲跑阀油孔面积随主液压缸行程的曲线组,同时得到了飞机航向的动力学性能。研究结果表明:通过改变定长冲跑阀的油孔面积,不同质量的飞机可在限定拦阻距离内拦停,飞机的拦阻力及拦阻距离均满足美军标取值范围。     

晶圆对心转台亚微米级径跳误差补偿方法

为了消除转台径跳误差对晶圆预对准台重复性定位精度的影响,提出径跳误差的在线检测与补偿方法。转台上方并与之一起旋转的心轴作为转台径跳的检测元件,电涡流传感器测量心轴径向距离,其测量值由固定误差和径跳误差组成,借助集合平均法或者转台径跳特性,离线求解固定误差,据此在线工作时从电涡流传感器数据中分离出径跳误差。利用该误差对激光位移传感器检测的晶圆边缘数据进行径跳误差补偿,分析误差特性,据此简化补偿算法。试验证明,径跳误差补偿方法的使用提高了系统的预对准精度,并最终使系统达到了微米级的定位精度要求。     

高炉煤气管道剩余壁厚检测装置研究

基于电磁激励式漏磁原理设计出一种新型检测装置,详细介绍检测原理、检测装置结构及参数确定。该装置周向均布有32组检测单元,确保了管道径向无漏检;采用由螺母丝杠副带动的变径机构,使之在Φ400~600 mm范围内的管道中均能可靠工作,大大提高了检测装置的作业环境适应性;柔性结构的设计为装置的过弯检测及弯管通过性提供了技术上的保障。该设计不但能够满足冶金企业高炉煤气管道剩余壁厚检测的需要,而且也可以应用于其他生产领域的金属管道无损检测中。