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We experimentally studied the quench properties of REBa2Cu3Oy (RE-123) coated conductors with various platedcopper thicknesses (20 and 40 m). A short sample of coated conductors was conduction-cooled to 45 K, a magnetic field (µ0H, up to 2 T) was applied perpendicular to its wide face to control the critical current, an operating current was supplied, and subsequently quench was initiated using a small heater. Normal zone propagation velocities (NZPVs) were measured at various operating currents, and the NZPVs of coated conductors with various copper thicknesses were compared with each other. To understand the impact of the copper stabilizer on quench protection, hot-spot temperatures were measured during the processes that simulate quench detection using voltage taps and protection using dump resistor. The maximum hot-spot temperatures were plotted against the operating current as well as the overall current density, and the impact of the thickness of the copper stabilizer on hot-spot temperature was examined. The impact of the initial temperature on hot-spot temperature was also studied.

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Haze is the phenomenon of visibility degradation caused by extinction effects related to the physicochemical properties of atmospheric particulate matter (APM). Atmosphere heterogeneous reactions can alter the physicochemical properties of APM. Therefore, it is important to understand the atmospheric heterogeneous reactions of APM in order to reveal the cause of haze. Herein, the current situation, developmental trend, source, and composition of APM pollution in China are reviewed. Additionally, we introduce the reaction characteristics and key chemical processes of common inorganic, organic, and mixed pollutant gases on the surface of mineral particles. The effects of mineral particulate matter on aggregation, regulation, and catalysis in the formation of atmospheric aerosols and the synergistic reaction mechanism of SO2, NO2, O3, and VOCs on the surfaces of different mineral particles are summarized. The problems existing in the current research on heterogeneous reactions on the surfaces of mineral particles are also evaluated. This paper aims to gain a deep understanding of the mechanism of mineral particulate matter promoting the formation of secondary aerosols and attempts to provide theoretical support for effective haze control.

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