Premature debonding failure is a serious problem for reinforced concrete (RC) members strengthened with carbon fibre reinforced polymer (CFRP) laminates. Although various mechanical anchorage systems have been proposed to prevent debonding between CFRP and RC beam, these systems are generally difficult to apply to narrow RC beams due to width limitations. In this study, to resolve the debonding problems, an innovative hybrid end-anchorage system was developed, which achieves self-locking of the externally bonded CFRP sheets. To achieve this hybrid anchorage, both ends of the CFRP sheet were wrapped around twin rods, and the sheet was bonded along the length of the tension side of the beam. Then, to fix the twin rods, two L-shaped brackets were bolted on the side of the beams. In total, five RC beam specimens with rectangular cross sections were prepared and strengthened in different manners and then subjected to four-point bending tests. The enhancement effect of the hybrid anchorage on the flexural behaviour of the strengthened RC beams was validated. With a larger CFRP width, the strengthening effect was more notable, especially when the concrete strength grade was higher. Existing formulas were used to calculate the characteristic moments of the strengthened RC beams, including the cracking moment, yield moment and ultimate moment, and the applicability of the models was examined. Based on the test results, the formula for the ultimate moment of the specimens with the end anchorage requires further investigation.

In the casting process, alloying elements Mo and Cr are needed to improve the wear resistance of medium manganese steels for low impact energy. The element Ti is added to avoid the high cost of expenditure for using Mo. This paper studies the effect of Ti and Cr on microstructure and properties of medium manganese steel. It shows that a large number of polygon, column, and square (Ti, Cr) C particles (<13 μm) are formed in the casting samples using the present heat treatment process. A new type of Ti–Cr modified medium manganese steel (Ti content of 0.56%–1.48%) is produced by using (Ti, Cr) C reinforced phase particles. Compared with the traditional medium manganese steel (blank), the hardness increases twice with a slight decrease in impact toughness [traditional and modified medium manganese steels (blank and steels A, B, and C) have values of 42.1 J/cm², 47.5 J/cm², 43.8 J/cm², and 37.9 J/cm²], and the wear resistance also increased nearly two times.

In this study, the complete mitochondrial genome sequence of black-footed ferret, Mustela nigripes, is determined for the first time. This mitogenome is 16,556 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 control region (D-loop). The overall base composition is A (32.9%), C (26.1%), G (13.8%), and T (27.2%), so the percentage of A and T (60.1%) is higher than that of G and C. Most of the genes are encoded on H-strand, except for the ND6 subunit gene and six tRNA genes. The complete mitochondrial genome sequence reported here would be useful for further phylogenetic analysis and conservation genetic studies in M. nigripes.

To address the failure of 25MnB crawler track steel due to insufficient strength and toughness, this study designed a new type of 25MnB crawler track steel and investigated the effects of the Nb content on its mechanical properties, microstructure, dislocation evolution, and precipitation behavior. The experimental results show that, compared to 25MnB steel without Nb, the addition of 0.03% Nb significantly increased the yield strength of the experimental steel to 1450 MPa, with an elongation rate of 15.9%. The room-temperature impact energy showed a slight improvement, while the low-temperature impact absorption energy improved notably, reaching 36 J at −40 °C. The microstructural characterization and analysis revealed that increasing the Nb content refined the effective grain size of prior austenite and martensite. The (Nb, Ti)C precipitates provided a higher precipitation driving force, promoting the formation of precipitates and increasing the average dislocation density. Additionally, the increased proportion of high-angle grain boundaries (HAGBs) enabled grain boundaries and precipitates to jointly hinder crack propagation. This study demonstrates that Nb-Ti microalloying can effectively enhance the strength, toughness, and plasticity of track steel, demonstrating promising application prospects.