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提出一种估计法拉弟族光线性双折射误差的近似公式,它可对双折射误差进行数值补偿,从而使测量精度得以提高. 相似文献
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超导共面波导谐振腔主要包括四分之一波长型和半波长型.本文对半波长超导共面波导谐振腔使用并联RLC电路进行等效分析,使用sonnet软件进行仿真其传输特性,通过电子束蒸发和激光直写等工艺制备出样品,在低温超导状态下使用矢量网络分析仪对其传输特性进行测量,以及通过持续降温方式研究其传输特性受温度的影响.实验表明:测得的谐振频率和外部品质因数与设计值吻合;谐振频率受动态电感的影响随温度降低而升高;外部品质因数随温度降低而保持基本不变;内部品质因先受导体损耗的影响随温度降低而急剧升高,当温度降低至一定温度后内部品质因数受介电损耗的影响随温度降低而保持基本不变;总品质因数在温度较高时主要来自于导体损耗,在温度较低时主要来自于介电损耗和外部品质因数,随温度的变化趋势和内部品质因数一致. 相似文献
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Y-type polycrystalline hexagonal ferrites Ba2Co2−x−yZnxCuyFe12O22 with 0≤x≤2 and 0≤y≤0.8 were prepared by the mixed-oxide route. Single phase Y-type ferrite powders were obtained after calcinations at 1000 °C. Samples sintered at 1200 °C show a permeability that increases with the substitution of Zn for Co and display maximum permeability of μ′=35 at 1 MHz for x=1.6 and y=0.4. A resonance frequency fr=500 MHz is observed for Zn-rich ferrites with y=0 and 0.4. The saturation magnetization increases with substitution of Zn for Co. Addition of Bi2O3 shifts the temperature of maximum shrinkage down to T≤950 °C. Moreover, an increase of the Cu-concentration further lowers the sintering temperature to T≤900 °C, enabling co-firing of the ferrites with Ag metallization for multilayer technologies. However, low-temperature firing reduces the permeability to μ′=10 and the resonance frequency is shifted to 1 GHz. Thus substituted hexagonal Y-type ferrites can be used as soft magnetic materials for multilayer inductors for high frequency applications. 相似文献
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A stroboscopic map for voltage-controlled single ended primary inductor converter (SEPIC) with pulse width modulation (PWM) is presented, where low-frequency oscillating phenomena such as quasi-periodic and intermittent quasi-periodic bifurcations occurring in the system are captured by numerical and experimental methods. According to bifurcation diagrams and nonlinear dynamical theory, the characteristics of the low-frequency oscillation and the mechanism for the appearance of the low-frequency oscillation are investigated. It is shown that as the controller parameter varies, the change in the conduction mode takes place from the continuous conduction mode (CCM) under the originally stable period one and high periodic orbits to the intermittent changes between CCM and discontinuous conduction mode (DCM), which may be related to the losing stability of the system and brought the system to exhibiting low-frequency oscillating behaviour in the time domain. Moreover, the occurrence of the intermittent quasi-periodic oscillation reflects that the system undergoes a Neimark--Sacker bifurcation. 相似文献
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研究并讨论了在新型柠檬酸盐体系铜电沉积工艺中电镀工艺参数对镀层形貌和颗粒尺寸的影响;利用X射线衍射(XRD)和X射线光电子能谱(XPS)表征了镀层的结构和组分存在状态;并将柠檬酸盐体系电沉积铜应用于微机电系统(MEMS)加工工艺.结果表明:在6 g.L-1 Cu2+,pH=7.0-8.5,1-2 A.dm-2,45℃,搅拌条件下可得到结晶细小,表面平整的致密铜镀层;镀层为面心立方多晶结构的单质铜,不含其他杂质.利用MEMS工艺成功制得平面电感,其有效的最大品质因数(Q)为12.75,达到了设计要求. 相似文献
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The voltage-current relationship and equivalent circuit implementation of parallel flux-controlled memristive circuits 下载免费PDF全文
A flux-controlled memristor characterized by smooth cubic nonlinearity is taken as an example, upon which the voltage-current relationships (VCRs) between two parallel memristive circuits - a parallel memristor and capacitor circuit (the parallel MC circuit), and a parallel memristor and inductor circuit (the parallel ML circuit) - are investigated. The results indicate that the VCR between these two parallel memristive circuits is closely related to the circuit parameters, and the frequency and amplitude of the sinusoidal voltage stimulus. An equivalent circuit model of the memristor is built, upon which the circuit simulations and exper/mental measurements of both the parallel MC circuit and the parallel ML circuit are performed, and the results verify the theoretical analysis results. 相似文献