Polymer matrix is vulnerable to fire hazards and needs to add flame retardants to enhance its performance and make its application scenarios more extensive. At this stage, it is more necessary to add multiple flame-retardant elements and build a multi-component synergistic system. Metal organic frameworks (MOFs) have been studied for nearly three decades since their introduction. MOFs are known for their structural advantages but have only been applied to flame-retardant polymers for a relatively short period of time. In this paper, we review the development of MOFs utilized as flame retardants and analyze the flame-retardant mechanisms in the gas phase and condensed phase from the original MOF materials, modified MOF composites, and MOF-derived composites as flame retardants, respectively. The effects of carbon-based materials, phosphorus-based materials, nitrogen-based materials, and biomass on the flame-retardant properties of polymers are discussed in the context of MOFs. The construction of MOF multi-structured flame retardants is also introduced, and a variety of MOF-based flame retardants with different morphologies are shown to broaden the ideas for subsequent research.

Microbially influenced concrete corrosion (MICC) causes substantial financial losses to modern societies. Concrete corrosion with various environmental factors has been studied extensively over several decades. With the enhancement of public awareness on the environmental and economic impacts of microbial corrosion, MICC draws increasingly public attention. In this review, the roles of various microbial communities on MICC and corresponding protective measures against MICC are described. Also, the current status and research methodology of MICC are discussed. Thus, this review aims at providing insight into MICC and its mechanisms as well as the development of protection possibilities.

Silicon carbide MOSFETs (SiC MOSFETs) have been widely used in high frequency power converters. Unfortunately, faster switching speed can cause overshoot, oscillation and electromagnetic interference problems. To improve the dynamic performance of SiC MOSFETs, the mechanism of the overshoots in drain current and drain-source voltage are analyzed, further, a voltage-injected active gate driver is proposed, which is to reduce the overshoot by injecting voltage to gate-source voltage at the moment of drain current rising and falling. Following, the proposed active gate driver has been designed and verified in a buck converter. Next, the overshoots and oscillations of the SiC MOSFET in drain-source voltage and drain current are compared in this buck converter between with the proposed gate driver and with the traditional gate diver. Besides, the switching losses and electromagnetic interference of the buck converter are evaluated with the proposed active gate driver. Finally, the evaluation results show the effectiveness of the proposed gate driver on electromagnetic interference suppression.

A projection method was used to develop ground-motion models (GMMs) to predict the peak ground accelerations (PGAs) that are used to assess the fourth and fifth generations of Chinese seismic hazard maps. In the present study, the projection method was applied to develop sets of projected GMMs to predict PGAs and spectral accelerations (SAs) that are applicable to different seismic regions in Mainland China. The projected GMMs were based on the GMMs from Next Generation Attenuation Relationships for Western US. It is shown that the projected GMMs differ slightly from their corresponding original versions and that the predicted median PGA values by the projected GMMs represent the instrumental ground-motion data well. These newly projected sets of GMMs were used to estimate the seismic hazard map and uniform hazard spectrum (UHS) for Mainland China. For the estimation, smoothed seismic source models and spatially varying magnitude-recurrence relations were developed based on historical earthquake catalog and completeness analysis. The results indicate that, in general, the estimated seismic hazard agrees with that reported in the fifth-generation Chinese seismic hazard map. However, large discrepancies were also observed for a few locations. These discrepancies are partly attributed to how the large historical earthquake events are spatially smoothed. In addition, it was observed that the estimated shape of the UHS for regions with a significant seismic hazard is relatively consistent but differs from the standardized seismic design spectrum recommended in the Chinese design code.