A novel dual-band bandpass filter (BPF) with a dual-plane structure is proposed. The dual-plane structure consists of a pair of microstrip feed lines with capacitive source-load coupling on the top layer and a meander multimode defected ground structure resonator (MMDGSR) on the bottom layer. Using the intrinsic characteristics of the MMDGSR, two passbands and four transmission zeros can be generated simultaneously. An experimental dual-band BPF operating at 2.45/5.8 GHz (WLAN application) has been designed and fabricated. This performance is verified by good agreement between the simulated and measured results.

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Compounds containing [B10H10]2− cluster are promising candidates that can be used as high energetic fuels and burning rate modifiers for propellants. The ignition and combustion behaviors of [N(C2H5)4]2B10H10 were investigated using a laser ignition system in air. Results show that [N(C2H5)4]2B10H10 (∼2.0 mm) is ignited with a delay of around 350 ms and threshold ignition energy of 0.7 J at laser ignition power density of 1.14×107 W/m2. Furthermore, the combustion of [N(C2H5)4]2B10H10 in air is found to undergo three stages of decomposition, incomplete combustion of the volatile pyrolytic products, and ejection and combustion of the molten dehydrogenated framework, giving massive smoke and a characteristic pyrotechnic flame.

Aluminum (Al) nanoparticles have been widely applied in propellants, but the ageing of Al nanoparticles will result in the degradation of propellant ignition performance. This paper experimentally investigates the ignition characteristics of newly prepared and aged Al nanoparticles, and improves the ignition performance of aged Al nanoparticles through elevating the heating rate. It was observed that, despite newly prepared or aged Al nanoparticles, their ignition included three stages: stage I – heating, stage II – melting, and stage III – evaporation. The temperature rise and time in stage I, melting temperature, and time in stage II and ignition temperature in stage III were separately discussed. It is found that the duration of each stage during the ignition of aged Al nanoparticles was much longer than that of newly prepared Al nanoparticles, testifying that ignition temperature of Al nanoparticles increased and ignition delay time elongated due to ageing. At elevated power density, the heating rate of Al nanoparticles increased, the heating, melting, and evaporating time shortened. The difference of ignition delay time between newly prepared and aged Al nanoparticles was significantly reduced. It means that the ignition performance can be improved through increasing the heating rate. Simultaneously, the energy conversation equation of each stage was built and discussed. It will be beneficial to deeply understand the ignition process and reveal the ignition mechanism of aged Al nanoparticles.

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