一种新颖的端盖搭子孔钻模

目前电机端盖搭子孔钻模均采用在钻模板上铣一外形尺寸与端盖搭子的外形尺寸相仿的搭子,操作时凭眼睛看搭子是否对齐,这样钻出来的孔难以保证图纸对称度的要求(如图1)。为了解决上述问题,对该钻模在结构上作了改进(如图2),改进后的钻模靠定位块4卡在端盖搭子的两边,端盖搭子的外形尺寸大点小点,也无妨,因通过弹簧可自动调节定位块的位置,然后将定位止口套进端盖止口便可。此种结构的钻模优点是操作方便,能确保搭子对称度的要求,故很受操作者的欢迎。     

太赫兹波在二维椭圆金属光子晶体的传输特性

研究了一种由金属椭圆柱构成的二维正三角晶格的光子晶体结构,并应用有限积分法对太赫兹波段TE模的传输特性进行了仿真分析。通过改变晶格常数和椭圆的长、短半轴,分析了太赫兹波段TE模在金属光子晶体中的传输特性。结果表明,椭圆柱比圆柱更容易得到大的禁带带隙,通过分组优化组合,得到了对TE模禁带带隙最宽且最佳的光子晶体结构。这为太赫兹波段的光子晶体带阻滤波器的开发与制作提供了参考依据。     

基于光纤布拉格光栅的流量温度复合传感研究

针对传统流量计测量参数单一和流量温度复合测量困难的问题,提出了一种基于光纤布拉格光栅的流量温度复合传感器.采用空心圆柱悬臂梁,减小了流体的压力损失,对端盖、悬臂梁和靶盘采用一体加工,增加了传感器的稳定性.首先,结合光纤布拉格光栅传感理论和流量温度复合传感理论,研究了基于光纤布拉格光栅的流量温度复合传感机理;然后,设计了...     

紧凑型线极化自跟踪馈源设计

提出了基于紧凑型同轴波导TE21模耦合器的Ku波段自跟踪天线。通过电壁的设置,使其中TE21模耦合器在缩减了传统耦合器一半长度的同时,在700MHz的带宽内保持对其它模式不低于55dB的隔离以及TE21模到每个矩形波导臂-6.3dB的耦合。以此紧凑型耦合器为基础,采用波纹波导和介质杆天线结合的方式设计了Ku波段线极化自跟踪天线。由于其旋转对称的方向图,该天线适合于用作自跟踪反射面天线的馈源。     

YB80～160电机端盖风罩固定螺孔底孔钻孔模

我厂生产的YB80～160电机在加工端盖风罩固定螺孔时常常容易出现废品。这是因为风罩固定螺孔不是在端盖端耳的中间,而是偏离端盖端耳中心的。我厂近来设计的端盖风罩固定螺孔底孔钻孔模在使用过程中避免了上述缺点,下面我们以YB132电机为例来说明 YB80～ 160电机端盖风罩固定螺孔底孔钻孔模的设计。     

电机零部件固定孔位置度的简易测量

电机零部件固定孔位置度的简易测量丹东电机厂戴景茂电机端盖、凸缘端盖、轴承内外盖固定孔位置度在产品零部件检验规范中均被规定为首检项。并且规定用固定孔位置度测量工具进行测量，测量较麻烦。其实端盖、凸缘端盖、轴承内外盖固定孔位置度用游标卡尺就可以测量。现介...     

微波铁氧体铁磁共振有效线宽扫频测量可调谐振腔设计

讨论了一种用于微波铁氧体铁磁共振有效线宽扫频测量的可调谐振腔,即TE011模式的圆柱谐振腔,通过手动或电动方式改变腔体大小,可实现谐振频率连续调节。介绍了其详细设计方法,给出了腔体直径和长度的计算方法。提出了多个腔体分段覆盖的方法,解决了单腔体结构导致的调谐精度差和Q值较低的问题。制作了样品进行验证,该样品采用两个谐振腔覆盖8~12GHz的调谐范围,第一个腔体直径52mm,调谐长度40~21.5mm,调谐频率范围为7.9~9.9GHz,第二个腔体直径42mm,调谐长度为33.4~17.8mm,调谐频率范围为9.8GHz~12.1GHz。测试结果表明调谐频率符合理论计算结果,Q值满足设计要求。     

一种新的输电线路工频阻抗参数测试仪研制

针对目前的输电线路参数测试仪存在的2个主要问题,即假定三相线路参数对称,以及在高感应干扰电压下难以准确测量,研制了一种新的输电线路工频阻抗参数测试仪.这种测试仪是基于在单相测试电源下建立起阻抗参数计算模型的一种新的测量原理.经过动模试验、现场实测,结果表明,该仪器测量数据稳定、精确,能够克服高感应干扰电压及三相不平衡对线路参数测试的影响,是一种新的、实用的线路参数测试仪器.     

倒梯形对称双脊波导传输特性的有限元分析

为了研究倒梯形对称双脊波导脊的结构参数变化对传输特性的影响,在MATLAB环境下应用有限元工具箱PDE进行二次编程,计算了倒梯形对称双脊波导在TE模式下的截止波长和单模带宽,分析研究了倒梯形对称双脊波导截止波长和单模带宽随结构参数的变化。数值结果表明,与相同条件下矩形、梯形脊波导比较,倒梯形脊波导的单模带宽较宽,截止波长最大。     

电机圆柱滚子轴承外圈拆卸的一种新的方法

针对电动机维修时,端盖与圆柱轴承结构的拆卸极易造或端面划伤或损坏,且费时费工也不安全,这里介绍一种新的拆卸圆柱滚子轴承外圈(NU式轴承)的方法.     

谐振腔微扰技术测量湿蒸汽两相流的理论分析

蒸汽湿度的准确测量对汽轮机的安全、经济运行和优化设计具有重要意义。根据湿蒸汽混合物的介电性质,采用微波谐振腔介质微扰理论,建立圆柱形谐振腔在TE011模式下测量蒸汽湿度的关系式。测量湿度与湿蒸汽的热物性、温度(压力)、谐振腔的谐振频率和相对频偏有关。湿蒸汽的温度(压力)降低、谐振腔的谐振频率升高、相对频偏升高,湿度测量结果会增大,反之减小。谐振频率降低、温度升高,湿度的测量精度提高。蒸汽湿度测量谐振腔的谐振频率建议在5~10 GHz。对某200 MW凝汽式汽轮机进行排汽湿度测量实验,湿度测量结果与理论计算值吻合,验证了微波谐振腔微扰法测量蒸汽湿度理论的正确性。     

同轴谐振腔测量片状介质材料的介电常数

基于同轴谐振腔,提出一种测量低损耗片状介质材料相对介电常数的方法。结合麦克斯韦方程组和电磁场边界条件,分析部分填充介质的同轴谐振腔内TEM谐振模,推导填充介质同轴谐振腔的本征方程。采用多项式拟合法简化计算模型。本文通过计算分析,设计一个空腔工作频率在1.8183 GHz的同轴谐振腔进行研究。在HFSS电磁仿真软件中进行仿真分析,研究填充介质材料的厚度和放置高度对测量结果的影响,仿真测量结果与理论模型结果一致。在实验中搭建测量系统实现全自动测量。实验测量同轴谐振腔空腔的谐振频率为1.8183 GHz。对FR4介质材料的相对介电常数进行测量。经过多次测量表明测量系统稳定性良好。实验结果符合实际标称值,与仿真误差小于5%,证明该方法的可行性和准确性。     

Mode‐matching analysis of a spit‐circular cavity resonator for measurement of the dielectric constant for film on a substrate

In this paper, we apply the mode‐matching technique (eigenmode expansion) to formulate an analytical model for a split cylindrical cavity resonator with a thick ceramic film layer sandwiched between two‐layer alumina substrates. We then compute the resonant frequencies with the TE₀₁₁ mode with an eigenvalue problem approach using the model formula. The quality factor (Q ‐factor) of the resonator is also calculated by applying the perturbation method to the analytical model. The validity of the proposed analytical technique is confirmed by applying this method to the estimation of permittivity of thick films as an inverse problem. Ceramic films (2 µm thickness) were synthesized using a chemical solution method onto 200‐µm‐thick, 50‐mm‐diameter alumina substrates. The complex permittivity of the films was then determined using the TE₀₁₁ mode split cylindrical cavity resonator in the 10‐GHz band. The extent of the edge effect at a sample insertion space was evaluated by comparing the estimated results through TE wave analysis using the mode‐matching method when the transverse resonance technique and the perturbation method were applied to calculate the resonant frequency and the dielectric Q ‐factor. The results obtained indicate that a difference of 0.153% in the permittivity of the alumina substrate causes differences of 6.10 and 3.75% in the measured permittivity and loss tangent, respectively, of 2‐µm‐thick ceramic film with a permittivity of ∼50. Differences in permittivity and loss tangent were more pronounced with thinner films. It was also confirmed that the estimated results for permittivity and the loss tangent values of these ceramic films were affected by the estimated permittivity value of the alumina substrate. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

微波脉冲与带缝嵌套腔体耦合的研究

为了解带缝腔体内耦合场分布特性,利用时域有限差分方法对微波脉冲与带缝嵌套矩形腔体系统(系统1)和带缝嵌套圆柱形腔体系统(系统2)的耦合过程进行了数值计算。计算表明两系统的外、内孔缝附近均存在场增强现象;两系统耦合过程存在相同的外孔缝耦合主脉冲、外孔缝场增强因子和脉宽展开现象,其内部腔体(Q2)中心点耦合场强峰值接近相等。相比各自的外部腔体(Q1)以及相同入射脉冲下的孔缝、同体积单层腔体内的耦合场强,两嵌套腔体的Q2内耦合场要弱。对两个系统的共振峰、共振频率点以及最大耦合函数曲线的研究结果表明,系统2在耦合过程中的腔体调制现象更明显,且在两种系统中,内孔缝使Q2内耦合波基于Q1内耦合波平均衰减约10 dB。     

适用于测量薄片材料复介电常数的改进TE01n腔法

本文提出一种适用于测量薄片材料复介电常数的改进TE01n谐振腔法.本方法将待测样品从短路活塞处抬高,即在待测薄片样品下面垫上已知复介电常数材料,以提高测量系统的灵敏度;如有必要也可以在待测薄片样品的上面压上一块已知复介电常数材料,提高样品材料的平整度,以减少空气隙带来的误差.文章推导了TE01n腔测量多层介质的理论计算公式,只要知道垫片和压块介质材料的复介电常数,通过实验测量和软件计算,就可以求得中间待测薄片的复介电常数.运用这种改进方案,我们对几种样品进行了测量,取得了较满意的结果.     

The computation of the input impedance of a biconical antenna by means of a method of segmentation based on 3D finite elements

The analysis of structures with complex geometries leads to the use of three‐dimensional numerical methods. Such devices can be unmanageable unless a segmentation technique is applied. In this work, a hybrid 3D finite‐element‐mode matching method, based on the generalized admittance matrix (GAM) is applied to the computation of the input impedance of a biconical antenna fed by a cylindrical cavity loaded with resonant slots and matched by a coupling network composed of three multi‐ridge circular irises and sections of circular waveguides. The structure is segmented into regions which are analysed separately and, by means of linking the partial matrices calculated, the generalized scattering matrix (GSM) is obtained. In order to validate the method, numerical results and measurements are compared. Copyright © 2003 John Wiley & Sons, Ltd.     

Scattering from periodically spaced longitudinal slots on a conducting cylinder

Scattered fields from a conducting circular cylinder perforated periodically with longitudinal slots are determined using Floquet’s theorem, and radar cross sections (RCSs) are computed and compared with the RCSs of a hollow conducting cylinder. RCSs are found to be vanishing at some specific angles and frequencies that depend on the periodicity of the slots and the radius of the cylindrical surface. Hence slotted cylinders may be used in frequency selective surface applications.     

不对称六相分数槽绕组磁势分析

针对不对称六相分数槽绕组合成磁势的对称性问题,采用槽号相位图法及单元电机理论,对三种典型的不对称六相绕组磁势进行分析.通过与对称三相及六相绕组比较,得出其合成磁势的性质与分数槽绕组每极每相槽数表达式的整数及小数部分取值有关,其变化规律是:在设计允许范围内,整数部分值选取的越大,其特性就越接近对称绕组;当整数部分值一定,...     

Polarization sensing with resonant cavity enhanced photodetectors

We describe a new method of sensing the linear polarization of light using resonant cavity enhanced (RCE) photodetectors. The RCE detectors are constructed by integrating a thin absorption region into an asymmetric Fabry-Perot cavity. The top reflector is formed by the semiconductor air interface while the bottom mirror is a distributed Bragg reflector (DBR). Quantum efficiency of these RCE devices can be controlled by tuning the cavity length by recessing the top surface of the detector for off-normal incidence of light the reflectivity of the semiconductor-air interface can be significantly different for TE(s) and TM(p) polarizations. A pair of monolithically integrated RCE photodetectors with cavity lengths tuned for resonance and antiresonance provide a large contrast in response to TE and TM polarizations. An alternative polarization sensor can be formed by vertically integrating a conventional and a RCE photodetector. We show that a large contrast in the TE/TM responsivities of the vertical cavity polarization detectors (VCPD) can be achieved, thus combining detection and polarization sensing in a single mesa semiconductor device. These devices alleviate the problems associated with the bulkiness and critical alignment constraints of the conventional sensors based on polarizing filters or splitters and have potential for fabrication of monolithic smart pixels and imaging arrays