稠油油藏出砂冷采技术实践

套保油田为普通稠油油藏,其开发的难点是常规冷采产能低、递减快,蒸汽吞吐开采注入压力过高破坏隔层导致底水上窜、注入压力过低不能保证注入蒸汽质量导致开采效果差。因此开展出砂冷采试验,经研究及现场试验形成了较完善的配套工艺技术,出砂冷采在套保油田白92块工业化应用,单井日产油达到10～30m^3／d,为常规冷采产量的10～20倍。     

基于Pro/EngineerWildfire的渐开线蜗杆参数化设计

说明了在Pro／Engineer wildfire环境下，对渐开线蜗杆的精确造型方法，实现了对渐开线蜗杆的参数化设计和修改。     

圆弧齿圆柱蜗杆副轮齿强度分析

介绍圆弧齿圆柱蜗杆副齿廓啮合原理,齿形车削加工方法,建立起GB9147—88圆弧齿圆柱蜗杆副蜗轮、蜗杆的有限元计算模型。分析蜗轮蜗杆啮合过程中2个特殊承载位置应力与位移的变化,用动力学理论计算出蜗杆传动固有频率、临界转速,为试制GB9147—88圆弧圆柱蜗杆减速器提供合理而可靠的理论依据。     

XL400设备头架蜗轮严重磨损研究

针对专用设备头架传动机构上的蜗轮磨损过快问题,用蜗轮齿面的接触疲劳强度计算对蜗轮的磨损进行研究,提出了解决措施:用直廓环面蜗杆传动替代阿基米德蜗杆传动,实践表明此法简单可行,是解决蜗轮磨损问题的良好方法。     

蜗杆斜齿轮传动重合度的研究

以汽车座椅角度调节驱动器为例介绍金属蜗杆与塑料斜齿轮传动副的应用。在参考文献的基础上推导出蜗杆斜齿轮传动重合度公式,分别绘制出压力角an、齿顶高系数han、变位系数x、蜗杆分度圆导程角γ、斜齿轮齿数z2对重合度的曲线图并分析各参数对重合度的影响。     

基于宏程序的多头蜗杆数控加工研究

针对多头蜗杆在加工中,存在切削力过大,刀具磨损严重,对操作技术人员要求较高,而且加工质量难以保证等一系列问题。通过对螺纹车刀刀具的几何角度、蜗杆加工时的切削方法以及切削用量的选择进行了系统分析和优化设计,充分发挥数控机床的功能参数特点,将数控切削中普通螺纹加工的循环指令与制造工艺技术灵活运用,开发出适用于大螺距的各种类型的特殊螺纹加工方法的宏程序,极大地拓展了数控机床的加工范围,实现了数控机床的二次开发。     

基于随动控制的蜗杆检测系统设计

提出一种基于随动预定位技术的环面蜗杆检测方法,通过建立蜗杆运动与测头运动的对应关系的理论模型,以每个采样点测量的蜗杆实际运动坐标映射下一采样点的测头坐标,再采用时间细分技术的高精度运动控制将测头提前定位到下一采样点,从而实现环面蜗杆加工误差的在线随动测量、特定喉部半径下的实际空间螺旋线测量。通过不同喉部半径下的多条螺旋线构建出环面蜗杆的实际轮廓面形,再与理论模型比对后获得相应的加工误差,根据这种方法设计了上、下位机组成的检测系统。     

大型工件转动定位机构设计

介绍一种大型工件转动定位传动机构的设计,采用A轴伺服电机分度,通过双蜗轮蜗杆及齿轮传动对卡盘上的工件进行分度定位,解决了大型工件定位精度不高及转动扭矩过大等问题。     

Associations between immune competence,stress responsiveness,and production in Holstein-Friesian and Holstein-Friesian × Jersey heifers reared in a pasture-based production system in Australia

The objectives of this study were to assess antibody and cellular immune responses in first-lactation dairy heifers reared under a pasture-based production system and to investigate associations between immune competence and stress responsiveness, health, and productivity. A commercial vaccine was used to induce antibody and cellular immune responses and, based on measured responses, animals were classified as above average, average, and below average for each trait independently and in combination (overall immune competence). Overall immune competence phenotypic rankings were generated by combining standardized residual values for antibody and cellular responses measured in individual heifers. Cortisol responses to handling and yarding were used to assess stress responsiveness, worm egg counts were used to assess internal parasite burden, somatic cell counts to assess udder health and estimates of total daily milk volume, and milk fat and milk protein contents to assess productivity. A total of 393 Holstein-Friesian and Holstein-Friesian × Jersey crossbred heifers from 2 herds practicing seasonal calving in a pasture-fed production system were enrolled in the study. The immune competence phenotypes of individual heifers were assessed before their first mating and their subsequent performance during their first lactation was monitored. Animals with below-average antibody and cellular immune competence had higher serum cortisol concentrations compared with their counterparts following handling, suggesting they had a reduced ability to cope with management-induced stress. Furthermore, a significant negative (favorable) correlation was observed between antibody responses and stress responsiveness. Similarly, correlations between antibody responses and internal parasite burden were significant and negative (favorable). No correlations were observed between overall immune competence and milk yield, milk fat, and milk protein content.     

蜗杆减速器的发热过程分析

本文研究了蜗杆减速器的发热和温升变化过程,并引入了蜗杆减速器的发热时间常数的概念。指出现行蜗杆传动热平衡计算公式的局限性,提出了适用于各种工况的蜗杆传动热平衡计算公式。