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In this paper, the genetic algorithms were used to realize optimization of the chemical vapor infiltration (CVI) process for manufacturing carbon–carbon composites for the first time. The density homogeneity, bulk density and infiltration time were selected as the optimizing objectives, and the density homogeneity was taken as the main optimizing objective. By combining selection, crossover and mutation operator of genetic algorithms with computer simulation technology, the CVI process parameters including deposition temperature and concentration of reacting gases had been optimized. After 30 generation evolutions, the fitness values were converged, and the optimized results were obtained. So, this paper has provided an effective optimization method for CVI process, which can solve the problem of difficulty of establishing a model for the process. [Copyright &y& Elsevier]

Ti 3 C 2 sheets with typical lamellar structure have been successfully obtained by etching Ti 3 AlC 2 powders in HF. The electromagnetic interference shielding effectiveness (EMI SE) of the Ti 3 C 2 /paraffin composites with different Ti 3 C 2 contents were measured in the frequency of 2.0–18.0 GHz. Results show that EMI SE increases with the filled content of Ti 3 C 2 , and the total shielding effectiveness reaches up to a maximum of 39.1 decibels (dB) for the Ti 3 C 2 /paraffin composites with 60 wt% Ti 3 C 2 and a thickness of 2.0 mm. The Ti 3 C 2 /paraffin composites are both absorptive and reflective to electromagnetic radiation, and the main shielding effectiveness is resulting from absorption. Our findings suggest these kinds of 2D transition metal carbides (MXene) will be good candidates for fabricating EMI SE composites with high performance and light weight. [ABSTRACT FROM AUTHOR]

• A sulfur cathode was fabricated by covalently bonding sulfur with UiO-66(SH) 2 @CNT. • The cathode can inhibit the shuttle effect and accelerate polysulfide conversion. • The assembled Li-S cells exhibit excellent electrochemical performance. The shuttle effect and sluggish reaction kinetics have hindered the practical application of lithium-sulfur (Li-S) batteries. In this work, a thiol-rich MOF was in situ synthesized on carbon nanotube (CNT) and sulfur was covalently connected to this composite to form a MOF-sulfur copolymer (S-UiO-66(SH) 2 @CNT). Benefiting from the strong covalent interaction between thiol groups and sulfur, the resultant cathode can retard the shuttle effect and simultaneously strengthen the redox kinetics. As a result, the S-UiO-66(SH) 2 @CNT cathode exhibits a higher capacity retention of 93.27 % at 0.5C during 200 cycles than that of the physically mixed S/UiO-66@CNT cathode (64.94 %). This work will provide insight into the design of advanced MOF-based cathodes for Li-S batteries. [ABSTRACT FROM AUTHOR]

A new type of oxidation-protective multi-composition coating for carbon/carbon (C/C) composites has been produced by a pack cementation technique in an argon atmosphere. XRD analyses shows that the phases of the composite coating are composed of Al2O3, mullite, SiC and Al4SiC4, and the bonding layer between the coating and C/C composites are composed of Al4C3, SiC and Al4SiC4. It is found by SEM surface observation and EDS area scanning analyses that the coating has two kinds of surfaces that are distinctly different in element content of Si and C. In the meantime, cross-section SEM observation of the coating also displays a dense microstructure. Oxidation test shows that the as-prepared coating characterized by excellent thermal shock resistance on the surface of C/C composites during exposure to an oxidizing atmosphere at 1773 K could effectively protect the C/C composites from oxidation for 41 h. [Copyright &y& Elsevier]