电子水准仪技术方案研究

采用目前具有最高运算速度及性能的DSP处理器的嵌入式软硬件解决方案,将CCD/CMOS技术、图像信息处理技术、DSP技术、嵌入式软件技术有机地整合在一体,以解决电子水准仪的自动读、记数据;采用自组织神经元网络模型进行条码模式智能识别,可做到仪器对条码标尺的通用性。     

管内扭带插入件强化沸腾换热技术的研究现状及展望

制冷设备对换热器紧凑化和小型化的需求促使人们开发新型的强化传热技术,而管内扭带插入件是一种廉价且易于制造的被动强化传热技术,在制冷系统蒸发器中具备良好的应用潜力。扭带插入两相沸腾换热的管中能够增大表面传热系数,但同时也增大了管内压降。分析发现,通常情况下,质量流量、干度的变化与表面传热系数和压降的变化呈正相关,而管径、扭率、饱和温度的变化与表面传热系数和压降的变化呈负相关。沸腾换热过程复杂、评价指标选取不一、实验工况数量有限等因素是导致各学者总结的扭带插入的最佳条件不一致的主要原因。本文收集了各作者预测的内插扭带管内沸腾换热的表面传热系数和压降的关联式,认为管内扭带插入件还需要进一步明确最佳使用条件,并需要结合蒸发器整机或变频压缩机加以研究。     

Perturbation solutions for flow through symmetrical hoppers with inserts and asymmetrical wedge hoppers

Under certain circumstances, an industrial hopper which operates under the “funnel-flow” regime can be converted to the “mass-flow” regime with the addition of a flow-corrective insert. This paper is concerned with calculating granular flow patterns near the outlet of hoppers that incorporate a particular type of insert, the cone-in-cone insert. The flow is considered to be quasi-static, and governed by the Coulomb-Mohr yield condition together with the non-dilatant double-shearing theory. In two-dimensions, the hoppers are wedge-shaped, and as such the formulation for the wedge-in-wedge hopper also includes the case of asymmetrical hoppers. A perturbation approach, valid for high angles of internal friction, is used for both two-dimensional and axially symmetric flows, with analytic results possible for both leading order and correction terms. This perturbation scheme is compared with numerical solutions to the governing equations, and is shown to work very well for angles of internal friction in excess of 45°.     

管内插入物强化传热及除垢的研究进展

介绍了内插物强化传热技术的特点,运用了场协同理论来解释其强化传热的机理,主要是速度矢量场和热流矢量场之间的协同对传热过程的影响。总结了近年来研究者们对管内插入扭带强化传热和除垢的研究结果及进展,并对将来的研究工作提出了建议。     

基于Matlab的可转位车刀切削部分优化

采用Matlab建立了可转位车刀切削部分优化计算的数学模型，并利用其优化工具箱进行优化，得到满足设计要求并使车刀前角值为最大的车刀刀片槽加工所需的几何参数。     

基于基因遗传算法的硬质合金刀片槽形的优化设计

本文在介绍了基因遗传算法的基础上，讨论了槽形特征参数的提取方法，定义了基于断屑范围预报意义下的适合度函数，最后给出了硬质合金刀片槽形的优化设计实例。     

Wettability and machinability study of pure aluminium towards uncoated and coated carbide cutting tool inserts

An investigation has been conducted to study wetting characteristics of aluminium towards different cutting tool materials for assessing the compatibility for dry machining of aluminum. For this purpose uncoated carbide (94%WC + 6%Co) and mono or multi-layer coated carbide tools with top coating of TiC, TiN, Al₂O₃ and diamond have been used. It was observed that aluminium had a tendency to wet uncoated carbide (94%WC + 6%Co) inserts. However, wetting was more pronounced when surface was enriched with cobalt. In contrast, wetting of aluminium was less when the WC content of the carbide tool surface increased. Coatings like TiC, TiN or Al₂O₃ could not show pure non-wetting characteristics for aluminium. The aluminium appeared to dissolve the coatings in different degrees. On the other hand, coating of diamond exhibited inertness towards aluminum leading to non-wetting behaviour. Turning test with aluminium indicated heavy material built up on uncoated (94%WC + 6%Co) tool. Built up edge formation could not be avoided when carbide inserts with a top coating of TiC, TiN, Al₂O₃ were engaged in machining of aluminium. However, the non-wetting characteristic of diamond coating was reflected during machining of aluminium. The chips slided smoothly over the rake face leaving no trace of edge built up.     

可转位浅孔钻的实体建模及网格划分

可转位浅孔钻内外刀片的径向非对称分布,导致钻削时将会产生径向合力,从而影响被加工孔的质量。为最大限度的减小加工时的径向合力,有效研究浅孔钻钻削过程,需借助有限元软件对其进行三维斜角切削分析。由于浅孔钻结构复杂,为创建有限元分析所需要的几何模型,采用Solid-Works软件建立可转位浅孔钻三维模型,并详细介绍了其建模过程;同时在有限元分析软件ANSYS里对其进行网格划分,为后续浅孔钻的应力、应变等分析做好充分准备工作。     

心型灯罩注塑模具设计

分析了心型灯罩塑件的工艺特点,详细介绍了的心型塑料灯结构设计和模具设计的过程。本模具采用一模两腔,即一次成型两个壳件的组合;并简单介绍了镶件的加工工艺。     

电器盖注射模设计

以电器盖注射模具设计为主线,研究了成型工艺、模具结构设计、模具零件的加工方法及模具的总装配等。介绍了一种电器盖注射模具,该模具采用一模两腔,即一次成型2个壳件的组合,同时,简单介绍了镶件的加工工艺。