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An impediment to the use of epitaxial YIG (yttrium iron garnet) in microwave devices has been the drift of the ferrimagnetic resonance field with temperature. This drift arises from the temperature sensitivity of the demagnetizing and anisotropy fields. By substituting Ga for some of the Fe and La for some of the Y in liquid phase epitaxial YIG, the demagnetizing and anisotropy field contributions to the drift were made self compensating. Temperature stability was thus achieved in perpendicular resonance. In parallel resonance there was a substantial reduction in drift. 相似文献
75.
ML Wang WB Liao MJ Bullard FC Lin PJ Lin CW Chiang SJ Liaw CH Chiang 《Canadian Metallurgical Quarterly》1997,61(9):767-771
We describe two sibs with chorioretinal dystrophy, hypogonadotrophic hypogonadism, and cerebellar ataxia, Boucher-Neuh?user syndrome, a rare but distinct pleiotropic single gene disorder with an autosomal recessive pattern of inheritance. The cases presented illustrate that this syndrome is still poorly recognised. We provide a review and analysis of previously reported cases and the differential diagnosis, which might aid in the identification of additional cases. 相似文献
76.
B. M. Liaw A. S. Kobayashi A. F. Emery 《International journal for numerical methods in engineering》1984,20(5):967-977
A simple dynamic finite element algorithm for analysing a propagating mixed mode crack tip is presented. A double noding technique, which can be easily incorporated into existing dynamic finite element codes, is used together with a corrected ? integral to extract modes I and II dynamic stress intensity factors of a propagating crack. The utility of the procedure is demonstrated by analysing test problems involving a mode I central crack propagating in a plate subjected to uniaxial tension, a stationary slanted central crack in a plate subjected to uniaxial inpact loading and an extending slanted-edge crack in plate subjected to uniaxial tension. 相似文献
77.
The application of a relatively new, thin-film bondable transducer, commercially available under the name KRAK-GAGE®2, was evaluated for corrosion fatigue crack propagation tests in a sea water (3.5%NaCl) environment at ambient temperature on an HY 80 steel. Fatigue crack growth data generated by this method are shown to be consistent with those obtained by the compliance method and the commonly used optical/visual measurements. Thus, this new instrumentation system appears to be a valuable addition for corrosion fatigue crack growth testing. Furthermore, test data acquisition and analysis of the KRAK-GAGE and the compliance method were computer automated, which results in considerable cost savings for such customarily labor intensive fatigue crack propagation experiments. Additionally, the FRAC-TOMAT/KRAK-GAGE instrumentation system can be utilized for direct test machine control, permitting completely automated fatigue crack growth testing. 相似文献
78.
An adaptive model-following speed controller for induction motor drives is proposed and implemented. This adaptive controller is easy to implement since, for the controlled plant, only the output signal is fed back. In order to choose a reference model with the desired drive dynamic behavior, a two-degree-of-freedom (2-DOF) controller is designed, using a systematic procedure based on the prescribed drive specifications. The reference model of the adaptive system is chosen as the transfer function of the controlled drive system by the 2-DOF controller in the nominal case. An adaptation signal is augmented to let the prescribed specifications be maintained under a wide range of operating conditions 相似文献
79.
A visible light active binary SnO2-TiO2 composite was successfully prepared by a sol-gel method and deposited on Ti sheet as a photoanode to degrade orange II dye. Titanium and SnO2 can promote the development of rutile phase of TiO2 and inhibit the formation of anatase phase of TiO2. Formation of SnO2 crystalline is insignificant even when the calcination temperature increases to 700 °C. Heterogenized interface between SnO2 and TiO2 inhibits growth of TiO2 linkage and leads to the particle-filled surface morphology of SnO2-containing films. The carbonaceous, Ti-O-C bonds and Ti3+ species are likely to account for the photoabsorption and photoelectrocatalytic (PEC) activity under visible light illumination. The electrode with 30% SnO2 exhibits higher photocurrent when compared with those in the region of 0-50%. The 600 °C-calcined SnO2-TiO2 electrode indicates higher activity when compared with those at 400, 500, 700 and 800 °C. PEC degradation of orange II follows the Langmuir-Hinshelwood model and takes place much effectively in a solution of pH 3.0 than those in pH 7.0 and pH 11.0. 相似文献
80.
A serial type, C+L-band hybrid amplifier based on a single pump laser diode is proposed. Dispersion management and gain equalisation among C+L-band channels are realised simultaneously. Pump reflectors and double-pass schemes are used to increase the pump slope efficiency. The power variation is reduced from 6.5 to 0.2 dB among C + L band channels. 相似文献