轴流泵叶片的数控加工

轴流泵可以输送清水、雨水、江河水、污水等液体介质,广泛用于工矿给排水、市政工程、污水处理、农田排灌、跨流域调水等领域,其主要特点是低扬程、大流量,和其他类型的泵相比,其效率较高。决定其效率的主要因素是其叶片设计和制造的水平。     

对位聚苯材质应用加工探讨

正对位聚苯材料的性能大大优于聚四氟乙烯制品,其使用寿命可比后者提高3~4倍,是冶金、化工、化肥、印染、机械、造纸、纺织、轻工等行业较为理想的耐磨密封材料。对位聚苯也称为聚苯撑,是以苯环为链接的高聚物。其耐高温性好,可用于火箭发动机部件和宇宙航行;其热稳定性好,可制作高温轴承材料;其耐腐蚀性好,可用作腐蚀环境和工作条件恶劣的轴承和化工设备;其自润滑性能优于二硫化钼和石墨     

金属中的气体分析

简要介绍了金属中氢、氧、氮气体在金属中存在状态和含量的不同对其性能的影响及提高其检出下限的各种方法以及影响其分析准确度、精密度的重要因素。     

浅谈企业如何搞好全面预算管理

本文论述了企业实施全面预算管理的意义、作用、原则和关键,得出了只要我们充分认识其意义,深刻领会其作用,认真坚持其原则,准确掌握其关键,那么,实施全面预算管理的工作就一定能搞好。     

叶片泵制造的研究

介绍了双作用叶片泵的制造方法，用这种方法可以提高其容积效率、降低其噪声和延长其使用寿命。     

液压缸的组装、调试与试验

1．组装液压缸组装之前，应将活塞组件放在液压缸内检查其活动状况，只有其活动灵活、无阻滞才可正式组装。将活塞杆与活塞组装在一起后，必须用百分表测量其同轴度和全长上的直线度，其差值须在允许范围之内。组装导向套、     

执行器的分类与发展

介绍了当前自动控制系统中常用的几种执行器，并按能源形式对其进行分类，分析了其工作特点、工作原理、适应范围，确信其必将随着科学技术的发展走智能化的道路。     

热泵多效浓缩器的特点、比较及中药水提的应用

对热泵双效、热泵三效浓缩器从设备组成、热泵原理、节能节水性能进行了详细的阐述,并将其技术性能指标与现有的普通双效、三效浓缩技术进行对比分析。结果显示,其具有低温加热、低温蒸发、节能节水的显著特点。其技术可应用于对中药厂已使用的普通单效、三效浓缩器的设备改造。     

创新型产业集群事关经济后续动力

创新型产业集群是产业集群的一种重要类型。我国创新型产业集群具有以下特点:市场是推动其形成的基础力量;中小企业是其基本主体;制造业是其主要行业;沿海发达地区是其主要分布区域。目前,我国发展创新型产业集群还存在认识模糊、制度环境不完善、层次偏低、分工协作水平较低等问题。     

碳化硅肖特基二极管仿真模型及其在自动化装置中的应用

根据碳化硅肖特基二极管半导体物理结构,在测量碳化硅二极管特性参数的基础上研究其静、动态性能及计算机仿真模型.针对其低的通态电阻、反向阳断电压高、高频率、存储电荷少的特点,在适合其应用的太阳能最大功率跟踪电路以及作为IGBT器件的续流二极管电路上研究了其反向恢复特性及对电路效率的提高.实验结果验证了模型的准确性与应用的优越性.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.