Recently, ‘Liquid crystal display (LCD) vs. organic light-emitting diode (OLED) display: who wins?’ has become a topic of heated debate. In this review, we perform a systematic and comparative study of these two flat panel display technologies. First, we review recent advances in LCDs and OLEDs, including material development, device configuration and system integration. Next we analyze and compare their performances by six key display metrics: response time, contrast ratio, color gamut, lifetime, power efficiency, and panel flexibility. In this section, we focus on two key parameters: motion picture response time (MPRT) and ambient contrast ratio (ACR), which dramatically affect image quality in practical application scenarios. MPRT determines the image blur of a moving picture, and ACR governs the perceived image contrast under ambient lighting conditions. It is intriguing that LCD can achieve comparable or even slightly better MPRT and ACR than OLED, although its response time and contrast ratio are generally perceived to be much inferior to those of OLED. Finally, three future trends are highlighted, including high dynamic range, virtual reality/augmented reality and smart displays with versatile functions.
Many factors influence WEDM(Wire-cut Electrical Discharge Machining) machining precision, and the influence of various factors on the machining precision are expressed by wire electrode dynamic form ultimately. In this paper, the transverse vibration theoretical model of the axially moving electrode wire coupled with thermal stresses is established by the principle of Hamilton. The influence of various processing parameters on machining precision are analyzed and simulated. This study provides a relevant theoretical basis for optimizing processing parameters, reducing the wire vibration and improving machining precision of workpiece.
Many factors influence WEDM (Wire-cut Electrical Discharge Machining) processing precision, and the influence of various factors on the processing precision are expressed by wire electrode dynamic form ultimately. In this paper, the transverse vibration theoretical model of the axially moving electrode wire coupled with thermal stresses is established by the principle of Hamilton. The influence of various processing parameters on wire vibration are analyzed and simulated. This study provides a relevant theoretical basis for optimizing processing parameters, reducing the wire vibration and improving machining precision.
This paper mainly addressed the workspace analysis and performance evaluation of a special class of the 6/6 cable-suspended parallel robot. Based on the screw theory and the static equilibrium, the Jacobian matrix of the cable -suspended parallel robot is constructed. The workspace volume is characterized as the set of points where the centroid of the moving platform can reach with tensions in all suspension cables for a constant orientation. This paper attempts to tackle some aspects of optimal design of this special class of the 6/6 cable-suspended parallel robot by addressing the variations of the workspace volume and the accuracy of the robot using different geometric configurations, different ratios and orientations of the moving platform. The global condition index is used as a performance index of a robot with respect to the force and velocity transmission over the whole workspace.
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