改装百分表在数控车床精确对刀中的运用

数控车床的对刀方法有试切法对刀和对刀仪对刀。对刀仪对刀可以达到较高的尺寸精度,但需要专用的对刀设备,而一般的数控车床都不具备这种专用的对刀设备;试切法对刀加工,操作简单,不需要专用的对刀设备,在一般的数控车床加工中运用很广泛,但零件长度方向的尺寸精度很难保证。为解决这一问题,现采用改装的百分表对刀,既不需要专用的对刀设备,又能保证零件长度方向的尺寸精度。     

基于OpenMP并行技术的多核环境下轮对图像处理方法研究

基于光电图像的轮对磨耗在线检测过程中,轮对图像处理的速度对在线检测的实时性有重要影响。针对轮对图像的处理速度不能够满足轮对高速在线检测要求的问题,利用多核处理器的计算优势,对基于Open MP并行技术的轮对图像处理方法进行了研究。通过分析轮对图像的特点,对不同类型的轮对图像采用了不同的分割方法,减小了轮对图像分割环节对后期处理的影响;提出了采用多图并行处理的编程模式,设计了并行优化方案,利用Open MP并行技术对轮对图像的处理进行了并行优化;并将Open MP四线程与单线程对轮对图像的处理结果进行了对比分析,验证了轮对图像处理加速效果。研究结果表明,多核环境下,轮对图像处理通过Open MP并行优化,获得了高于2倍的加速比,可满足车辆轮对检测速度达到80 km/h的在线检测要求。     

数控车削加工的对刀方法及技巧

以FANUC—Oi系统为例,分析了数控车削加工时的对刀原理,介绍了车削加工时的对刀方法,并结合实际应用提出了一些对刀技巧,对提高对刀的准确性和对刀效率有指导意义。     

基于GA-BP神经网络的列车轮对振动信号研究

轮对作为列车行驶的关键走行部件,对其故障的实时检测与精确诊断具有重要意义。通过小波包算法对轮对振动信号进行分解,提取轮对故障特征向量,以此作为输入参数,建立GA-BP诊断模型,采集振动信号样本对模型进行训练和测试。试验结果表明：GA-BP算法能够对轮对故障做出精确诊断。设计了轮对故障监测软件,实现了轮对信息监测的实时化与可视化。     

基于圆跳动发展跟踪的镟修策略优化方法

为保证地铁列车安全平稳运行,需定期对轮对进行预防性镟修。制定合理的镟修周期,有助于延长轮对的使用寿命,减少轮对维护工作量。现根据广州地铁七号线开通运营两年以来轮对的运用情况及开展的轮对圆跳动发展跟踪研究,对轮对镟修周期进行了优化分析,找出了一种轮对镟修周期跟踪研究模式,并提出了轮对镟修策略优化建议。     

电解加工间隙检测系统的研制及试验研究

为实现复合进给电解加工机床对刀间隙的实时控制和检测,研制了一种以PMAC多轴运动控制卡、对刀电源和NI6221USB数据采集卡为主要硬件的对刀系统。在研制机床对刀系统过程中,用LabVIEW作为上位机软件开发平台对机床对刀系统进行开发,并设计了人性化的操作界面。为了验证机床对刀系统的可靠性和稳定性进行了对刀试验。试验结果表明,该系统能够实现对刀电流的采集以及间隙的控制,操作方便,稳定可靠,满足了研发要求。     

CRH3动车轮对压装选配

轮对的压装质量与其性能有着直接的关系。传统的轮对压装多是依据经验来进行轮轴的选配,没有明确的参考标准,因而导致压装合格率较低。文章以CRH3型动车组轮对为例,利用Ansys软件建立了二维轴对称模型对轮对压装过程进行模拟仿真,通过非线性接触分析得出过盈量、摩擦因数、公差等因素对轮对压装应力分布及压装曲线的影响。结果表明,过盈量对轮对应力及压装曲线均有较大的影响;摩擦因数对应力值影响较小,对压装曲线则影响较大;公差对轮对应力影响比较明显,对压装曲线的影响则比较微弱。最后在满足国家标准要求的前提下给出一个范围,以此作为轮对压装的参考标准,可提高轮对压装的质量,保证机车安全平稳运行。     

基于有限元的轮对强度计算及评定

根据轮对实际运用情况和受力状态,运用有限元技术对某新型160km/h宽轨客车轮对强度进行计算,详细介绍了对铁道车辆轮对强度进行分析的方法,并对计算结果进行了评定.     

振动筛综合故障的辨识诊断分析

通过对振动筛振动故障的辨识,及早地发现故障,不致使其继续发展,并及时对其进行维护 ,可使维修成本降低,对保证正常生产具有重要意义.通过对正常状态和故障状态时振动筛的振动数据分别进行分析研究,对故障信号予以辨识,找出了相应的辨识方法.     

液力涡流过滤器过滤性能试验

介绍了液力涡流过滤器的分离机理,分析了在对润滑油中固体颗粒分离的过程中,油液的性质对过滤效率的重要性,并且对影响过滤效果的因素进行了试验研究.结果表明,油温和流量等参数对分离的效果有密切关系,油液温度越高,对颗粒的分离效果越好;当流量超过100 L/min时,温度达到65 ℃,过滤器对粒径大于10 μm的颗粒有良好的过滤效果.     

Comparison of osmium/sonication and edta/sonication microdissection techniques in exposing the adepithelial basal lamina surface of developing rat colon

We have used two epithelial-stripping techniques in our studies of the basal lamina in the developing rat colon. The first involves prolonged osmication followed by sonication; the second uses chelation of calcium by EDTA followed by sonication. Both techniques remove the epithelium from the basal lamina; however, the EDTA/sonication technique appears to produce a cleaner adepithelial surface of the basal lamina. In addition, the fine structure of the basal lamina appears to be better preserved in specimens prepared by the EDTA/sonication technique. In contrast, the basal lamina of specimens prepared by the osmium/sonication technique has a shattered appearance that we believe is due to an increase in the fragility of the delicate fetal basal lamina.     

Ti600/TC17钛合金惯性摩擦焊接头组织与力学性能研究

采用惯性摩擦焊方法对TC17和Ti600钛合金进行了连接,着重分析接头焊态和热处理条件下的组织特征与力学性能。接头焊态TC17一侧：在热力影响区原始β晶粒发生破碎,晶界以及晶内α相扭曲变形;在再结晶区β晶粒发生动态再结晶形成细小的等轴晶粒,晶内为亚稳态的β相;接头Ti600一侧：在热力影响区片层组织随着金属流动发生变形;在再结晶区,α片层团簇发生再结晶形成大量细小的α片层团簇片层。经过热处理后,TC17钛合金一侧亚稳态β相析出细小的层片状α相,Ti600钛合金一侧层状α相长大,但是不明显。热处理使接头的显微硬度升高,TC17钛合金焊缝一侧显微硬度增加明显。接头抗拉强度与Ti600母材相当,断裂发生在Ti600钛合金一侧,断口为典型的杯锥状断口。     

基于激光熔覆技术的航空发动机涡轮叶片裂纹修复新工艺

航空发动机涡轮叶片裂纹的修复是飞机修理工作中的难题,目前国内对涡轮叶片裂纹的修复工艺研究甚少。本文研究了基于激光熔覆技术的航空发动机涡轮叶片裂纹修复新工艺,设计出了涡轮叶片裂纹的激光修复系统,得出了修复工艺过程和主要工艺参数。应用该工艺修复叶片裂纹,其质量满足使用需要。     

Buckling of a heavy lamina by an edge displacement

A heavy lamina lies horizontally. By pushing on one edge the lamina buckles. This paper studies the post-buckling characteristics for a given edge displacement. The heavy elastica equations are solved by perturbation and by numerical integration.     

Immunogold labelling of the intermediate filament-lamina-nuclear matrix system in hela and bhk-21 cells

Whole-mount, sequentially extracted cells combined with immunogold electron microscopy were developed to demonstrate the intermediate filaments, lamina, and nuclear matrix (IF-L-NM) and to identify their protein components. The IFs of HeLa cells were reacted both with keratin and vimentin monoclonal antibodies; meanwhile, the IF network of BHK-21 cell was reacted only with vimentin monoclonal antibody. The lamina and nuclear matrices of both HeLa and BHK-21 cell were labelled, respectively, with lamin monoclonal antibody-gold complex and 280 Kd nuclear matrix protein monoclonal antibody-gold complex. The monoclonal antibody to keratin could cross-react with the lamina both of HeLa and BHK-21 cells.     

Investigations of the pathway of incorporation and function of lamin A in the nuclear lamina

Cell-free extracts of Xenopus eggs were used to investigate how differing lamin sub-types are incorporated into a lamina and how lamina composition influences DNA replication. Purified recombinant human lamin A (HlaminA) was inoculated into egg extracts, which support in vitro nuclear assembly. The route of incorporation of Hlamin A into the lamina was compared to Xenopus lamin B3 (XlaminB3), the major endogenous lamin sub-type in egg extracts. While Xlamin B3 was incorporated into the lamina directly, HlaminA first accumulated at nucleoplasmic foci, before entering the lamina. When HlaminA was inoculated into extracts depleted of XlaminB3 it entered nuclei efficiently and was incorporated into nucleoplasmic foci. However, in the absence of XlaminB3, HlaminA remained in the foci and did not enter the nuclear envelope. When HlaminA entered the nuclear envelope, it did not influence DNA replication. Nuclei containing HlaminA initiated DNA replication on queue and in addition the spatial distribution of replication centres in these nuclei was identical to controls. Taken together, these results suggest that the incorporation of A-type lamins into the nuclear envelope is dependent upon the presence of B-type lamins. However, the presence of A-type lamins alone is not sufficient to influence the spatial and temporal order of DNA replication.     

一种高效节能型轴流式搅拌桨功率曲线测定及分析

新近开发的一种高效节能型轴流式搅拌桨--JH-2型轴流式搅拌桨是一种空间扭曲板材型搅拌桨,该桨型设计时考虑了桨叶背面的曲面形状对流场的影响,减低了桨叶尾部的流体脱附,大大降低了能耗.在标准搅拌实验台上对JH-2桨进行功率实验,给出了JH-2型扭弯叶片轴流式搅拌桨的功率曲线及其关联式,并在同等实验条件下与三折叶桨进行功率对比分析,表明JH-2型搅拌桨比三折叶桨至少可节省20%～30%的功率.     

基于最终失效强度的层合板结构的鲁棒优化分析

采用有限元方法分析复合材料层合板结构的最终失效强度，并以此对结构进行优化和鲁棒优化分析。层合板结构同时承受面内和面外载荷，每个单层板考虑基体失效和纤维断裂两种失效模式。当某一单层失效后采用比率退化法计算结构新的刚度，然后重新进行结构分析，直到求得结构的最终失效强度。以纤维方向角和层合板厚度作为设计变量，最终失效强度为目标，对结构进行优化。在此基础上，考虑了层合板结构的鲁棒优化分析。     

A study on finite element of pre damaged stress concentration factor for a composite laminate member with central circular

The study investigates the pre damaged stress concentration factor (SCF) for a composite laminate member (CLM) with central circular hole subjected to tensile loading. The presence of holes yields high stress concentrations in the structural members termed as stress raiser and often regarded as an important design deriver. The pre damaged SCF refers to the stress concentrations within elastic (undamaged) range of the CLM prior to the failure initiation. The traditional experimental and analytical methods for the estimation of SCF offer macro level behaviour which is not considered appropriate for CLM where lamina by lamina behaviour is more significant. A meso level finite element (FE) model is presented to capture the lamina by lamina influence on the overall SCF for a CLM using commercial software Abaqus. The paper deals with the fundamental influencing factors such as laminae orientation effect, stress distribution effect around periphery of the hole, decaying effect and ligament effect on SCF for CLM. Analytical models have been formulated to validate the FE models. The results of FE models have been found in close agreement with the analytical results.     

基于Solidworks轴流泵叶轮叶片的三维建模方法

轴流泵叶轮叶片是一种特殊的曲面零件,这种零件的几何造型是三维建模中的重点和难点。基于Solidworks的三维建模功能,研究了轴流泵叶轮叶片的三维建模方法,并以具体实例实现了轴流泵叶轮叶片的三维模型。