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A novel flame retardant (FR) containing phosphorus and calixarene structures was synthesized, and the FR combined with ammonium polyphosphate (APP) was then incorporated into polystyrene (PS). The flame retardancy and thermal stability of the flame retardant composites were investigated. The limiting oxygen index can reach 21.0% when the mass ratio of FR/APP was 3:2. Char residues at 650°C in an air atmosphere increased from 2.2% to 21.5% notably when FR/APP was incorporated into PS matrix, indicating an improvement of thermo‐oxidation resistance. Compared to the virgin PS and FR/PS composites, the peak heat release rate of FR/APP/PS composites is reduced to 259.87 kW/m2 (PS8), indicating synergistic flame retardant effects between FR and APP. Generally, stable char layer of FR/APP/PS is responsible for the improved flame retardant properties, which not only effectively prevented the release of combustion gases but also protect the interior substrate from oxygen and heat permeation.

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Switched inductor (SI) converters are popular in applications requiring a steeper conversion ratio. However, these converters operate a twin inductor switching cell, which complicates the small-signal modeling. This paper proposes an expeditious small-signal analysis method to model the SI converters. The offered modeling approach is hinged on the analogy existing between the SI converters and certain Tapped Inductor (TI) converters. It is suggested here that by virtue of the analogy of the SI converters and TI converters the small-signal model of the SI converter is identical to that of its ideal TI counterpart. Hence, the recently developed Tapped Inductor Switcher (TIS) methodology can be applied to the modeling of the SI converters as well. As an example, the small-signal model of the Switched Inductor Buck converter is obtained. Theoretical analysis was confirmed by simulation and experimental results. In addition, several other SI converters and their TI counterparts are identified.

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