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The current router security issues focus on the mining and utilization of memory-type vulnerabilities, but there is low interest in detecting backdoors.Hard-coded backdoor is one of the most common backdoors, which is simple and convenient to set up and can be implemented with only a small amount of code.However, it is difficult to be discovered and often causes serious safety hazard and economic loss.The triggering process of hard-coded backdoor is inseparable from string comparison functions.Therefore, the detection of hard-coded backdoors relies on string comparison functions, which are mainly divided into static analysis method and symbolic execution method.The former has a high degree of automation, but has a high false positive rate and poor detection results.The latter has a high accuracy rate, but cannot automate large-scale detection of firmware, and faces the problem of path explosion or even unable to constrain solution.Aiming at the above problems, a hard-coded backdoor detection algorithm based on string text semantic conflict (Stect) was proposed since static analysis and the think of stain analysis.Stect started from the commonly used string comparison functions, combined with the characteristics of MIPS and ARM architectures, and extracted a set of paths with the same start and end nodes using function call relationships, control flow graphs, and branching selection dependent strings.If the strings in the successfully verified set of paths have semantic conflict, it means that there is a hard-coded backdoor in the router firmware.In order to evaluate the detection effect of Stect, 1 074 collected device images were tested and compared with other backdoor detection methods.Experimental results show that Stect has a better detection effect compared with existing backdoor detection methods including Costin and Stringer: 8 hard-coded backdoor images detected from image data set, and the recall rate reached 88.89%.

Mass failures are often induced or activated by the variation of hydrological factors within a reservoir area. Clarifying the relationships between the failure volume and different hydrological factors may help to identify both the dominant factors influencing reservoir bank failures and the most hazardous combinations of factors inducing such events. This study examines the influence of different hydrological factors on bank failures using model experiments incorporating variations in rainfall, wave and water level. The results indicate that the coupled effects of heavy rainfall and falling water‐level had the most significant impact on bank failure. The cumulative failure mass of the reservoir bank peaked at 177.2 × 103 cm3 under the coupled effects of rainfall and falling water‐level. In comparison, the cumulative mass failures on the reservoir bank under rainfall superimposed onto waves and rainfall superimposed onto water level rise were 162.4 × 103 and 129.2 × 103 cm3, respectively. The impact of heavy rainfall significantly contributed the mass failures on soil reservoir bank. The analysis reveals that the highest cumulative failure, 106.3 × 103 cm3, occurred during periods of heavy rainfall. Compared with heavy rainfall, the cumulative failure volumes in the reservoir experienced a reduction of 46% and 55% under solely declining and solely rising reservoir water levels, respectively. The early phases of changing hydrological conditions have a significant effect on the stability of the soil reservoir bank. Mass failures on the bank predominantly occurred during the initial three events of the five simulation experiments performed for each landform, which could account for up to 87% of the total volume. Hence, it is advisable to avoid lowering reservoir water levels during periods of sustained heavy rainfall in order to mitigate the risk of bank failure. [ABSTRACT FROM AUTHOR]

NbHfTiVC0.1 refractory high-entropy alloy (RHEA) exhibits excellent comprehensive mechanical properties and demonstrates great potential for applications. However, the mechanical properties need to be improved further. In this work, hot rolling on NbHfTiVC0.1 RHEA at temperatures of 650 °C, 850 °C, and 1050 °C, with total reductions of up to 30%, 50%, 70%, and 80%, was conducted. The microstructure and mechanical property evolution of the samples were further investigated. The hot-rolled samples at 650 °C and 850 °C exhibit a composition consisting of BCC, carbide, and Laves phases, whereas the samples rolled at 1050 °C only consist of BCC and carbide phases. The 650-80 sample displays the highest ultimate tensile strength (1354 MPa), and the 1050-80 sample demonstrates the highest elongation (16%). The highest strength observed in the 650 °C-80% sample can be attributed to the presence of fractured and refined carbides, fine-grains, and the hindrance of dislocation slip by the fine Laves phase. At a higher rolling temperature (1050 °C), the Laves phase disappears, resulting in a reduction in strength but an increase in plasticity. Furthermore, the dislocation slipping mechanism within the BCC matrix also contributes positively to plastic deformation, leading to a notable increase in ductility for the 1050 °C-80% sample. These research findings provide valuable insights into enhancing the strength and ductility simultaneously of NbHfTiVC0.1 RHEA through hot rolling. [ABSTRACT FROM AUTHOR]

Eutectic high-entropy alloys (EHEAs) can achieve a balance of high strength and ductility. It has been found that the mechanical properties of hypoeutectic high-entropy alloys are superior to those of EHEAs. In this work, hypereutectic Al1.1CoCrFeNi2.1 alloy was prepared, and the mechanical properties in a wide temperature range were studied. The presence of both soft ordered L12 and hard BCC (B2) phases results in a combination of ductile and brittle fracture modes. The Al1.1CoCrFeNi2.1 hypereutectic high-entropy alloy contains more primary soft L12 phases, which ensure excellent ductility. Moreover, the Orowan by-passing mechanism caused by the B2 precipitates increases in the strength of the alloy for low-temperature tensile tests (−100 °C and 23 ± 2 °C). The −100 °C test exhibits a dimple morphology and demonstrates the highest ultimate tensile strength of 1231 MPa, along with an excellent elongation of 44%. At high tensile temperatures (650 °C, 750 °C, and 850 °C), the dislocation cutting mechanism and dynamic recrystallization increase the plasticity. However, the presence of a large number of cracks near the spherical primary L12 phase significantly reduces the ductility and strength. The results show that the hypereutectic Al1.1CoCrFeNi2.1 exhibits superior plasticity and strength properties at low temperatures. The findings of the article provide a new approach to enhancing the comprehensive mechanical properties of hypereutectic alloys. [ABSTRACT FROM AUTHOR]

Zr-Ti-Nb-Ta alloys were synthesized in parallel via multi-target co-sputtering deposition with physical masking in a pseudo-ternary Ti-Nb-ZrTa alloy system. Sixteen alloys with distinct compositions were obtained. Comprehensive characterization of phase structure, microstructure, Young's modulus, and nanoindentation hardness was undertaken. The Ti-Nb-ZrTa alloys exhibited two typical phase structures: a single-BCC solid-solution structure, and an amorphous structure. Nanoindentation quantification confirmed a Young's modulus ranging from 110 to 130 GPa, alongside nanoindentation hardness spanning 3.6 to 5.0 GPa. The combination of good hardness and a relatively low Young's modulus renders these alloys promising candidates for excellent biomedical materials. This work not only offers an effective method for the high-throughput synthesis of multi-principal element alloys, but also sheds light on a strategy for screening the phase structure and mechanical performance within a given alloy system. [ABSTRACT FROM AUTHOR]