The effect of Mg doping on the electrical and optical properties of the p-GaN/AlGaN structures on a Si substrate grown by metal organic chemical vapor deposition was investigated. The Hall measurement showed that the activation efficiency of the sample with a 450 sccm Cp2Mg flow rate reached a maximum value of 2.22%. No reversion of the hole concentration was observed due to the existence of stress in the designed sample structures. This is attributed to the higher Mg-to-Ga incorporation rate resulting from the restriction of self-compensation under compressive strain. In addition, by using an AlN interlayer (IL) at the interface of p-GaN/AlGaN, the activation rate can be further improved after the doping concentration reaches saturation, and the diffusion of Mg atoms can also be effectively suppressed. A high hole concentration of about 1.3 × 1018 cm−3 can be achieved in the p-GaN/AlN-IL/AlGaN structure.
A sponge airport is a new concept of airport stormwater management, which can effectively relieve airport flooding and promote the usage of rainwater resources, often including the application of low impact development (LID) facilities. Although many airports in China have been chosen to implement sponge airport construction, there is a lack of quantitative evaluation on the effect of LID facilities. This paper takes Beijing Daxing International Airport as a case study and develops a comprehensive evaluation on the effect of LID facilities using the storm water management model (SWMM). The performance of four LID design scenarios with different locations and sizes of the rain barrel, the vegetative swale, the green roof, and the storage tank were analyzed. After LID, the water depth of J7 reduces from 0.6 m to 0.2 m, and duration of accumulated water reduces from 5 hours to 2.5 hours. The water depth of J17 reduces from 0.5 m to 0.1 m, and duration of accumulated water reduces from 2 hours to 15 minutes. The capacity of conduits has been greatly improved (Link 7 and Link 17). The application of LID facilities greatly improves rainwater removal capacity and effectively alleviates the waterlogging risk in the study area.
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