厌氧降解和生物接触氧化法处理奥里油废水的实验研究

本文介绍了以奥里油为原料生产重交沥青的生产废水处理工艺,通过实验模拟,探索了该类废水的生物处理效果,并总结出了该废水生物处理启动调试经验.实验证明,用该工艺处理是可行的,厌氧降解处理COD负荷8.7 kg·m-3d-1,平均去除率达35%,好氧处理COD负荷1.87 kg·m-3d-1,平均去除率达69%,生物处理总的COD平均去除率达80%.最终出水达到GB8978-1996二级排放标准.     

分形理论在农业工程中的应用

综述了分形理论在粗糙表面表征、摩擦温升分布、磨损预测模型、机器故障诊断、土壤耕作和计算机水果检测中的应用现状。     

平面弹性接触问题的光弹性-数值组合解法

利用光弹性 -数值组合解法对平面弹性接触问题进行了研究 .利用边界积分方程 ,结合接触状态 ,形成接触问题的系统方程 .采用增量迭代的方法 ,通过计算程序求得数值解 .由光弹性实验得出实验解 ,并将此解与数值解进行比较 ,结果相近     

ANALYTICAL SOLUTION OF RING SHELL LINING WITH ANNULARLY VERTICAL WALLS MADE CONTACT WITH SURROUNDING ROCK

In this paper,the ring shell lining with annularly verticalwalls made contact with the surrounding rock is considered as a combinationstructure formed of ring shell,inner and outer annular barrels on elastic fo-undation.The complex equation and its solutions of ring shell under deadload of lining and vertical and horizontal surrounding rock pressures are de-rived by the method of complex function.The governing equation and itssolution of the barrels on elastic foundation are also derived by theory ofcylindrical shell.And then,the ring shell lining is assembled by the subst-ructures by means of compatibility conditions of internal forces and defor-mations between them.In the paper,all formulas for the practical computa-tion in engineering are derived,the numerical examples are given and theeffects of the parameters of the lining on the work behaviours of lining alsoare discussed preliminarily     

Study on Mismatched Engagement of Hourglass Worm Gearing with The Worm Generated by A Cone and The Wheel Generdted by A Straight Profile Hob

A method to make the hourglass worm gearing with the property of mismatchedpoint contact has been proposed.The worm and the hob of the worm gearing is generated by a coneand a straight line located on the cone respectively. The basic principle of the worm gearing has beenanalysed. The formulas for calcultating the machining parameters has been obtained. And the toothcontact of the worm gearing has been investigated.The result shows that this worm gearing could getopint contact well.     

Determination of Load Share between Gear Teeth with Contact Finite Element Method

The determination of load share between teeth is a complex problem in gear strength calculation. On the basis of contact finite element method this paper considers the production-assembly error as initial gap to get the finite element model which meets load share between teeth in gear meshing. Through calculating and comparing the result with that from ISO formula to get the load share between teeth which meets the requirements in actual usage.     

采用遗传算法计入摩擦力作用的标准斜齿轮传动模糊可靠优化

传统的齿轮强度理论不考虑齿间摩擦的影响。针对这一观点，该文以渐开线斜齿圆柱齿轮传动的小齿轮齿数、法面模数、螺旋角、齿宽系数为设计变量，以两齿轮的体积之和为最小目标函数，通过应用模糊设计理论和可靠性设计理论，建立摩擦力作用下标准斜齿圆柱齿轮传动的模糊可靠性优化设计的数学模型，并采用遗传算法对其进行优化。研究表明，效果很好。     

狗猪鹿牙齿的高耐磨特性对比

为解决土壤工作部件磨损严重的问题,该文以狗牙、猪牙、鹿牙为研究对象,采用摩擦磨损试验机进行摩擦磨损试验,考察了狗牙、猪牙、鹿牙的摩擦学性能,通过激光共聚焦扫描显微镜测量磨损深度,利用扫描电子显微镜观察狗牙、猪牙、鹿牙的磨损形貌,利用纳米压痕仪分别对狗牙、猪牙、鹿牙进行力学性能试验,测试其纳米硬度和弹性模量。试验表明：狗牙釉质磨斑表面磨屑剥落严重、附着大量的细小磨粒、有明显的龟裂现象,磨损体积为1.91×107 μm3,猪牙釉质磨斑表面主要是磨屑剥落,磨损体积为1.56×107 μm3,鹿牙釉质磨斑表面也表现为磨屑剥落,磨损程度比猪牙齿的轻,磨损体积为1.39×107 μm3;牙齿的耐磨性与其硬度密切相关;鹿牙釉质的耐磨性、纳米硬度和弹性模量最大,狗牙釉质的最小。该文以动物牙齿为仿生原型,为耐磨触土部件的研发提供新的参考方向和理论依据。     

外掺植物纤维对冻融作用下植被混凝土抗剪强度的影响

[目的]研究外掺2种植物纤维对冻融作用下植被混凝土抗剪强度的影响,为植被混凝土生态防护技术在高寒地区的应用提供科学依据。[方法]参考相关标准(GB/T50082-2009)中的慢冻法,采用2因素3水平全面交叉试验开展研究。[结果]未掺植物纤维的植被混凝土,冻融后黏聚力显著减小,内摩擦角变化不明显。掺入植物纤维可使经受5次冻融循环作用后植被混凝土的内摩擦角平均增加5°左右,并且随植物纤维掺量的增加,内摩擦角变化无明显规律,黏聚力则呈先增加后减小的趋势。表明纤维加筋对黏聚力的贡献存在临界掺量。棕纤维掺量对黏聚力的影响比黄麻纤维掺量更为敏感。[结论]外掺植物纤维可有效改善植被混凝土抵抗冻融破坏的能力,棕纤维和黄麻纤维的建议掺入比为0.6%和0.6%,具备推广应用前景。     

考虑摩擦特性时过盈量对轴承预紧力的影响

针对航天机构中轴承轴向预紧力精确确定的问题,基于静力学和弹性力学,在考虑配合尺寸、摩擦特性的基础上,研究了轴承预紧力与拧紧力矩的关系。利用锁紧螺母拧紧力矩与轴向力的关系,确定施加于轴承上的轴向力;根据摩擦力与摩擦特性及装配尺寸的关系,分析摩擦力对轴向力的截留作用;通过轴承力平衡方程组,对实际预紧力进行理论分析。文中研究了配合尺寸及摩擦特性对预紧力的影响,揭示了不同装配下预紧力随拧紧力矩的变化规律。研究结果表明:对轴承71807C预紧力结果进行分析,发现相同拧紧力矩下,过盈量增0.5μm,轴向力中约有123 N的力被截留;且摩擦系数增加0.05,轴向力截留率增大约13%。过盈量越大,轴承与主轴间摩擦力对轴向力的截留作用越大,预紧力对应的拧紧力矩越大;相比加热炉加热,油槽加热降低了配合区域的摩擦系数,加载相同的拧紧力矩时使轴承预紧力较大。经试验验证,该理论分析可以确定施加的预紧力,又可以提高装配质量。该研究建立预紧力测量的理论计算模型,并可用此模型较精确地确定预紧力,为轴承预紧力设计和装配提供参考。