The influence of graphene oxide (GO) and polyvinyl alcohol (PVA) fiber on the mechanical performance, durability, and microstructure of cement-based materials was investigated in this study. The results revealed that compared with a control sample, the mechanical strength and durability of cement-based materials were significantly improved by adding PVA fiber and GO. The compressive and flexural strength at 28 d were increased by 30.2% and 39.3%, respectively. The chloride migration coefficient at 28 d was reduced from 7.3 × 10−12 m2/s to 4.3 × 10−12 m2/s. Under a sulfate corrosion condition for 135 d, the compressive and flexural strength still showed a 13.9% and 12.3% gain, respectively. Furthermore, from the Mercury Intrusion Porosimetry (MIP) test, with the incorporation of GO, the cumulative porosity decreased from more than 0.13 cm3/g to about 0.03 cm3/g, and the proportion of large capillary pores reduced from around 80% to 30% and that of medium capillary pores increased from approximately 20% to 50%. Scanning electron microscope (SEM) images showed a significant amount of hydration products adhering to the surface of PVA fiber in the GO and PVA fiber modified sample. The addition of GO coupling with PVA fiber in cement-based materials could promote hydration of cement, refine the microstructure, and significantly improve mechanical strength and durability.

This paper presents a kind of concatenated polar codes called hash-polar codes with flexible outer code lengths, in which a hash function-based encoder is used as an outer encoder. A partial hashpolar code is also proposed to enhance the error-correcting performance at high signal-to-noise ratios. Since polar codes have been recommended by 3GPP as the channel coding scheme for the 5G enhanced mobile broadband control channel, the design of hash-polar codes for 5G is considered, where both good errorcorrecting performance and low false alarm rate (FAR) are required. The simulation results show that, under the 5G FAR requirement, the proposed hash-polar codes have similar frame error rate performance to cyclic redundancy check (CRC)-polar codes and perform better than parity check polar codes. In order to support early termination (ET) for 5G coding, we then propose segmented hash-polar codes, which exhibit the advantages of the ET gain compared with both CRC-polar codes and distributed CRC-polar codes.INDEX TERMS Concatenated polar codes, hash-polar codes, false alarm rate, early-termination, 5G channel codes.

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The bandwidth of a modulator is limited by the clock rate due to the oversampling ratio requirement. As the nanoscale CMOS processes are developing rapidly, it is possible to design wide bandwidth and high dynamic range continuous-time modulators for high-frequency applications. This paper proposes a 3rd-order 4-bit continuous-time modulator with a single-loop feedforward topology. This modulator is designed in a 40-nm CMOS process and achieves 80-dB dynamic range and a 100-MHz bandwidth at a clock rate of 2.4 GHz. The modulator consumes 69.7 mW from 1.2 V power supply.