A sticker breakout is a significant occurrence which not only disturbs steady state casting but also reduces plant productivity and efficiency. Optimising the casting parameters and increasing the accuracy rate of breakout prediction systems are two effective measures for reducing breakouts. In the present paper, plant data were collected and the influence of casting parameters such as slab dimension, casting speed and mould level on sticker breakouts were analysed, especially the effect of heat flux. In addition, sticker propagation behaviour characteristics, including vertical velocity, horizontal velocity and propagation angle, were investigated by measuring the temperature of the mould copper plates. These results provide a reference for optimising the casting parameters and enhancing the accuracy of breakout prevention systems.
It is very important to obtain reliable lubrication from casting powder both at the meniscus and in the gap between strand and mould as it affects slab surface quality and caster productivity. With knowledge of mould friction, a quantitative insight into the behaviour of powder during caster operation is possible. In the present research, the friction was studied based on a slab continuous caster equipped with hydraulic oscillators. The effects of mould oscillation and the abrupt change of casting speed on mould friction force were evaluated, and the characteristics of lubrication behaviour in a casting sequence were investigated. In particular, a comparison between the mould friction force between sinusoidal oscillation mode and non-sinusoidal oscillation mode was made. Finally, the characteristics of friction before a breakout are discussed. The experimental and analytical results may contribute to the development of mould friction online measurement and more clearly learn the lubrication behaviour in different conditions.
In this work, electrohydrodynamic atomization Layer‐by‐Layer deposition was used to deposit cathode catalyst layers (CLs) at different working distances of 3, 5, and 7 mm. The influence of working distance on the structural characteristics of cathode CLs was analyzed. The cyclic voltammograms of the cathode electrodes with different structures and the performance of the assembled membrane‐electrode assemblies (MEAs) were examined. It was observed that the cathode CLs presented well‐packed and porous features. The dispersity of the deposited catalyst and the thickness of cathode CL increased with higher working distance, which resulted in larger electrochemical active surface area (ESA), higher performance of the assembled MEAs and higher catalyst utilization. The ESA increased by approximately 70% when the cathode CL produced at the working distance of 7 mm compared with that at 3 mm. The peak power density of 56.1 mW cm–2 and the peak cathode catalyst specific power of 140.3 mW mg–1 Pt were obtained when the cathode CLs produced at the working distance of 7 mm.
PZT wafers are the core driving parts to adjust the laser resonant cavity length of laser gyro. Usually, the PZT wafers are used in pairs, and the paired PZT wafers need to have close piezoelectric coefficient. To handle the pairing and screening of PZT wafers, an automatic deformation measuring equipment is developed by using a cartesian-coordinate robot frame, in which multiple photoelectric sensors are used to detect the key motion position automatically. Besides, vacuum absorption technology is also used in picking, carrying and placing PZT wafers to protect them from accidental injury. When driving voltage is applied to PZT wafer, the resulting micro displacement is measured by dual opposite inductive probes with relative measurement principle. This measuring strategy eliminates the influence of placement error of PZT wafers on the final measuring result. Compared with the existing manual measurement, the efficiency can be improved by 60%. The experimental results show that the equipment has high reliability and consistency. The measurement accuracy in full scale is no more than 0.5 μm and the repeat accuracy is superior to 0.1 μm.
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