华中数控系统知识讲座——电磁兼容性设计：第9讲 电源滤波及干扰抑制

滤波技术用来抑制沿导线传输的传导干扰,主要用于电源干扰和信号线干扰抑制。滤波器是由电感、电容、电阻或铁氧体器件构成的频率选择性网络,可以插入传输线中,抑制不需要的频率进行传播。 一、电源滤波器 电源滤波器的作用是双向的,它不仅可以阻止电网中的噪声进入设备,也可以抑制设备产生的噪声污染电网。 1.电源线滤波器的结构     

Ni-SiC/铁氧体复合材料涂层的制备及其吸波性能

为了获得成本低、吸波性能良好、吸收带宽较大的电磁波吸收涂层,运用高压液相氢还原工艺对SiC粉体进行表面镀镍,并与铁氧体复合,制备了Ni-SiC/铁氧体复合材料吸波涂层,研究了单一材料与复合材料吸波涂层在8～18 GHz频段内的吸波性能,并研究了不同材料的电磁参数.结果表明:表面镀镍的SiC粉体与铁氧体复合后,可使该复合材料的复磁导率和复介电常数得到较合理的调整,使频散效应增强,从而使Ni-SiC/铁氧体复合材料吸波涂层的吸收峰值提高、吸收带宽增加,在15.2 GHz达到最小反射率-22.85 dB,且小于-10 dB的有效吸收带宽为7 GHz,吸波性能得到显著改善.     

碳酸钙增强树脂基复合材料的摩擦磨损性能

以具有强度高、模量高、耐热与隔热性好等优良特性的碳酸钙晶须为增强体,采用热压成型工艺制备出晶须增强树脂基制动材料,采用JF150D-Ⅱ型定速摩擦试验机研究了碳酸钙晶须的含量对复合材料摩擦磨损性能的影响。结果表明,碳酸钙晶须含量在20%左右时,试样的摩擦系数为0.41,磨损率为0.36,具有较好的摩擦磨损性能;对碳酸钙晶须进行适当偶联处理后,能有效地改善复合材料的摩擦性能。     

弹性磁复合材料的硫化性能及硫化胶特性

弹性磁复合材料是以铁磁填料作为一个成分,橡胶共混作为聚合物基质的材料。而复合材料的最终性能主要取决于聚合物基质的特性。但加入磁性填料后可赋予材料新的性能和功能。铁氧体代表了一类非常成熟的磁性填料,本研究使用的M型六角铁氧体是氧化铁和通式为MeO·6Fe203的其他一些金属氧化物的混合物（其中M为二阶阳离子,如Sr、Ba和Pb）。     

铁氧体磁环在医疗设备脉冲群测试中的应用

电快速脉冲群测试是医疗设备电磁兼容的重要测试项目之一.介绍了医疗设备脉冲群测试方法和铁氧体磁环的抑制原理,详细分析了铁氧体磁环不同匝数和尺寸对抑制效果的影响.结合某手术机器人系统整改实例,验证了应用铁氧体磁环抑制脉冲群干扰的可行性和有效性,为工程师正确使用铁氧体磁环提供了参考.     

纳米高岭土和石墨填充PTFE复合材料摩擦磨损性能

采用模压法制备石墨和纳米高岭土填充的聚四氟乙烯(PTFE)复合材料,在往复式滑动摩擦磨损试验机上测试了其的干滑动摩擦磨损性能,试验机往复频率为1.0 Hz.用扫描电镜观测和分析试样的磨损表面.结果表明:石墨和纳米高岭土共同填充的PTFE,在改善其耐磨性的同时,又保持了低的摩擦因数,其中含10%高岭土和5%石墨的PTFE复合材料表现最佳,稳定阶段的摩擦因数保持在0.11左右,耐磨性比纯PTFE提高了大约90倍.     

销盘式复合材料小样磨损实验装置研制

介绍了一种用于复合材料小型试样磨损性能测试的简易磨损实验装置,通过测试多组复合材料试样在不同转速、压力和时间段下的磨损量,对比分析试样的耐磨性能,为复合材料工艺和性能优化提供参照数据,适合用于复合材料研制初期的对比磨损性能测试分析.     

一体化电机伺服系统传导干扰抑制措施研究

从一体化电机伺服系统传导干扰有效抑制措施的需要出发,及时了解和掌握一体化电机伺服系统传导干扰的最新抑制技术和方法,为研究一体化电机伺服系统传导干扰的有效抑制措施提供必要的技术资料和参考对比方案,对目前相关文献已报道的各种一体化电机伺服系统传导干扰抑制技术和方法进行了研究与综述,归纳为减小干扰源强度和切断传导干扰传播途径两大类抑制方法,并指出各种方法的优缺点及其关键技术,最后展望了一体化电机伺服系统传导干扰有待解决的问题及其发展趋势,为研究人员研究一体化电机伺服系统传导干扰的抑制提供了参考.     

纤维表面处理对芳纶-预氧化丝混杂纤维增强NAFC材料耐温性能的影响

分别采用偶联剂、氧化剂和胶粘剂作为表面处理剂,以非石棉纤维增强橡胶基密封复合材料（NAFC）高温时效处理后的残余横向抗拉强度为指标,研究了不同的纤维表面方法对增强纤维与橡胶的结合度以及对NAFC材料高温性能的影响.试验结果和试样拉伸断面扫描电镜照片分析表明,采用RFL乳液作为芳纶-预氧化丝混杂纤维增强NAFC材料的纤维表面处理剂,对提高材料的高温性能具有较好的效果.     

花生壳粉填充树脂基制动材料的摩擦学性能研究

为了解决复合材料的环保降解问题和废弃资源循环再利用,将花生壳粉作为填料添加到树脂基制动摩擦材料中,采用干法热压成型制备试样,通过CHASE试验机测试其摩擦学性能,并用扫描电镜对磨损表面进行观察分析。试验结果表明:在复合材料中加入花生壳粉能显著提高摩擦系数,改善材料热稳定性,同时还能减小其磨损量,提高其耐磨性;当花生壳粉含量为30%时,其摩擦学性能最佳,此时试样磨损表面形成了大量的摩擦膜,磨损形式主要以粘着磨损为主、磨粒磨损为辅。     

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...     

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.     

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。     

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...     

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。     

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。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.