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When permanent magnets are surrounded by ferromagnetic materials, the magnetic field lines are rerouted in the air gap between them, which provides an approach for the optimum design of the eddy current damper. To improve the conventional tubular eddy current damper design, an enhanced eddy current damper with a ferromagnetic shaft and a ferromagnetic layer is successfully developed in this study. It is passive, cost-efficient and reliable, significantly boosting the damping effect without occupying extra space. To explore the benefits of the ferromagnetic material, analytical models of the magnetic field distributions are derived to estimate the damping coefficient. In addition, the ferromagnetic material configuration and dimensions of the proposed eddy current damper are optimized for better vibration suppression. The experiment results agree reasonably well with the theoretical models and finite element predictions, and demonstrate the effectiveness and efficiency of this innovative design, which realizes a remarkable improvement in the damping coefficient, from 70.5 N · s m−1 to 143.2 N · s m−1. [ABSTRACT FROM AUTHOR]

By designing double emissive layers, orange light-emitting layer (EML) and red EML and a space layer of blending hole-transporting material (HTM) with electron-transporting material (ETM), we have achieved efficient and colortunable organic light-emitting diodes (OLEDs). It is found that the red shift of EL spectrum was enhanced when the ratio of HTM to ETM was 5:1. And a maximum current efficiency of 41.17 cd/A was reached. It has been demonstrated that two ultra-thin emissive layers could improve the current efficiency of the OLEDs. The current efficiency of the OLEDs with a 1 nm o;6range EML and a 1 nm red EML was enhanced by 27.4 % as compared to the reference devices. This is a novel approach to realizing voltage-controlled electroluminescence (EL) over different colors and intensity in a single OLED. The color-tunable OLEDs show the potential to be utilized as rear light on motor vehicle. We have investigated the effect of the ratio of HTM to ETM on the efficiency and spectral shift of the OLEDs through the control of recommendation zone. [ABSTRACT FROM AUTHOR]

The disturbing effect of the stray magnetic fields of Fe-based amorphous ribbons on the giant magnetoimpedance (GMI) sensor has been investigated systematically in this paper. Two simple methods were used for examining the disturbing effect of the stray magnetic fields of ribbons on the GMI sensor. In order to study the influence of the stray magnetic fields on the GMI effect, the square-shaped amorphous ribbons were tested in front, at the back, on the left and on the top of a meander-line GMI sensor made up of soft ferromagnetic films, respectively. Experimental results show that the presence of ribbons in front or at the back of GMI sensor shifts the GMI curve to a lower external magnetic field. On the contrary, the presence of ribbons on the left or on the top of the GMI sensor shifts the GMI curve to a higher external magnetic field, which is related to the coupling effect of the external magnetic field and the stray magnetic fields. The influence of the area and angle of ribbons on GMI was also studied in this work. The GMI sensor exhibits high linearity for detection of the stray magnetic fields, which has made it feasible to construct a sensitive magnetometer for detecting the typical stray magnetic fields of general soft ferromagnetic materials. [ABSTRACT FROM AUTHOR]