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In recent years, with the continuous application of superacid-catalyzed condensation reaction in the preparation of anion exchange membranes (AEMs), a number of AEMs with excellent performance have been designed. Among them, the method to copolymerize two aromatic compounds with piperidone via a superacid-catalyzed reaction to synthesize anionic conducting copolymers has been widely discussed by researchers. Here, we focus on the introduction of poly­(N-alkylcarbazole-co-terphenyl N,N′-dimethylpiperidinium) (PCTP-n), which is formed by copolymerizing different chain lengths of N-alkylcarbazole (AHC, n = 2, 4, and 6) and p-terphenyl with 1-methyl-4-piperidone (1M4P). As a result of the high-curvature backbone and hydrophobic flexible side chains, the PCTP-n AEMs show comprehensive performance advantage. Among them, the PCTP-6 membrane, with an ultralow swelling (7.9%) and an excellent OH– conductivity retention (91.9% in 2 M NaOH at 80 °C after 1080 h), highlights high dimensional stability and alkaline resistance. Then, the PCTP-2 membrane displays excellent mechanical robustness (EB: 40%, TS: 20 MPa) and a decent OH– conductivity (134 mS cm–1 at 80 °C). Furthermore, the PCTP-2-based single cell exhibits a decent power density of 542 mW cm–2 under H2–O2 condition.

Because the anisotropy of shale formation should result in that wellbore deviations is unpredictable, the bit-rock interaction should be fully lucubrated in order to eliminate this problem. The impact of shale rock anisotropy and the cutting velocity on the load of PDC cutter wasn’t considered by the existing cutter-rock interaction models. On the basis of experiments of cutting shale with PDC cutter, using the stress tensor analysis theory, the relationship between the shale rock anisotropy and the cutter’s force is proposed in this paper. A new cutter-rock interaction model was established, and then a new bit-rock interaction model was set up. That applying these models to the ROP prediction of directional PDC bit can improve forecast accuracy is found.

The application of anion exchange membranes (AEMs) in alkaline fuel cells is profoundly affected by its performance. In this work, Tröger’s base microporous AEMs with hyperbranched structure (QA-BTB-x%) are prepared by superacid catalysis. The introduction of the hyperbranched structure can enhance the free volume of the AEMs, which will improve the water uptake (WU) of the AEMs and thus promote the transport of OH–. By increasing the content of the branching agent from 0% to 8%, the WU of the AEMs gradually increased from 41.7% to 62.6% at 80 °C. The maximum OH– conductivity of the QA-BTB-5% AEMs can reach to 95.2 mS cm–1 in ultrapure water at 80 °C with a low swelling ratio (14.9% at 80 °C). Small angle X-ray scattering (SAXS), atomic force microscopy (AFM) and transmission electron microscopy (TEM) show that the QA-BTB-5% AEMs has a good microphase separation structure that is beneficial for OH– transport. After a long-term alkaline stability test, the QA-BTB-5% still has a high OH– conductivity. The maximum power density of the QA-BTB-5%-based single cell can reach to 548 mW cm–2 in H2/O2. All of the results demonstrate obvious performance enhancements of AEMs upon the introduction of hyperbranched structure into the polymer backbone.