Ozone treatment is widely regarded as an effective postharvest preservation strategy; however, its underlying metabolic regulatory mechanisms in Hami melon (Cucumis melo L.) remain unclear. In this study, integrative metabolomics combined with weighted gene co-expression network analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment was employed to investigate ozone-induced metabolic reprogramming during postharvest storage. Differential metabolites were identified using combined multivariate and univariate statistical analyses, including partial least squares discriminant analysis (PLS-DA) and volcano plot analysis, and then integrated with WGCNA-derived hub metabolites to obtain key intersection metabolites. The results showed that ozone treatment significantly reshaped metabolic profiles, with key metabolites mainly associated with carbohydrate metabolism, amino acid metabolism, and transport-related processes, and broadly distributed across multiple co-expression modules, indicating strong network-level metabolic coordination. KEGG pathway enrichment analysis of the intersection metabolites revealed enrichment in carbohydrate metabolism, amino acid metabolism, and ABC transporter-related processes, suggesting coordinated regulation of primary metabolism and transport systems under ozone treatment. Integration of metabolite profiling and network analysis demonstrated that ozone induces a network-coupled metabolic system that integrates carbon and nitrogen metabolism into a unified regulatory architecture rather than acting through isolated pathway responses. Overall, this study reveals a systems-level metabolic response to ozone treatment in Hami melon. Coordinated metabolic reprogramming was associated with enhanced antioxidant capacity and physiological stability, leading to delayed senescence and prolonged postharvest shelf life.
At present, low-dimensional chaotic systems have deficiencies such as insufficient randomness, limited key space, and uneven sequence distribution, which make the security performance and anti-attack ability of the color image encryption algorithms constructed based on them insufficient and easy to be cracked, thus restricting the application of chaotic theory in the field of image encryption. In response to the above issues, this paper first constructs a three-dimensional dynamical system and proposes a three-dimensional logarithmic-exponential type trigonometrically (sin, cos) coupled chaotic dynamical system (3D-LECCS), this 3D-LECCS is explicitly defined as a globally bounded volume-expanding hyperchaotic system. Meanwhile, through bifurcation diagrams, Lyapunov exponents, sample entropy, permutation entropy, 0–1 chaotic state determination, NIST, and multistability analysis, the hyperchaotic characteristics and complex phase space motion behavior of 3D-LECCS are verified. Secondly, by leveraging the cryptographic properties of this system, a dynamic mapping cascaded encoding encryption mechanism for color images driven by 3D-LECCS (LECCS-CIEA) is designed. This scheme builds a strong nonlinear coupling correlation among the RGB three channels of color images through dynamic spatial partitioning cross-channel remapping and encoding cascaded XOR diffusion strategy. Finally, through theoretical analysis and simulation experiments, it is verified that LECCS-CIEA has good security and anti-attack ability. At the same time, the excellent chaotic performance of 3D-LECCS is also verified, confirming its reliability as an encryption entropy source.
Many types of polynitro biimidazole-based energetic materials are designed by the addition of furazan, tetrazine, and tetrazole rings combined with energetic groups, such as –CN, –NHNH2, –NH2, –NO2, –NHNO2, –N3, –CH(NO2)2, and –C(NO2)3. The results show that tetrazole ring and azide functional group acts as the most favorable side in enhancing the values of heats of formation (ranging from 322.6 to 1520.7 kJ mol−1). Most of the designed compounds possess excellent detonation pressure and detonation velocity (range from 7.68 to 9.33 km s−1 and from 26.0 to 41.4 GPa). The variations in the detonation pressure and detonation velocity of the designed compounds generally follow the same trends as the changes in oxygen balance and heat of detonation, which indicates that the oxygen balance and heats of detonation have a significant influence on their detonation performance. Considering both detonation performance and stability, compounds A2 and B4 are ultimately selected as potential high-energy–density compounds. All the results may provide potential insights for expanding the diversity of molecular designs for energetic materials.
CONTEXT:Energetic materials based on bis(4-nitropyrazole)-bridged nitrogen-rich heterocycles are designed, and their physical and chemical properties are fully investigated. Their heats of formation, detonation performance, and impact sensitivities are fully investigated. The results indicate that the addition of a tetrazole/-N3 functional group contributes to an increase in the heats of formation of the designed compounds, while the incorporation of a tetrazole/-C(NO2)3 functional group is beneficial for enhancing their detonation performance. By comprehensively balancing energy performance and stability, candidate compounds A2 and E2 are screened out since these compounds possess better detonation performance and lower impact sensitivities than those of RDX. To further understand the physicochemical properties of the selected compounds, electronic structures such as frontier molecular orbitals and molecular electrostatic potential are simulated and analyzed. METHOD:The optimization of the designed compounds is performed with the Gaussian 16 program suite using the DFT-B3LYP method at the 6-311G(d,p) level. Multiwfn_3.8_dev is used to compute molecular surface properties. Employing the VMD program, the molecular electrostatic potential (ESP) distributions for compounds A2 and E2 are plotted. The initial decomposition mechanism and total decomposition process of A2 are investigated using the CASTEP code.
In this study, welding thermal cycle experiments of X80 line pipe steel were conducted using a Gleeble-3500 thermo-mechanical simulator, with primary peak temperatures of 1150 °C, 1250 °C, and 1350 °C, followed by secondary peak temperatures ranging from 720 °C to 820 °C. Combined with microstructural characterization, microhardness measurements, and electrochemical hydrogen permeation tests, the morphology, size, distribution, and hydrogen trapping behavior of martensite/austenite (M/A) constituents were systematically investigated. The results demonstrate that the intercritically reheated coarse-grained heat-affected zone (ICCGHAZ) exhibits a lower effective hydrogen diffusion coefficients, along with higher hydrogen concentrations (C0) and hydrogen trap density (Nt) compared with the the coarse-grained heat-affected zone (CGHAZ), indicating a greater susceptibility to hydrogen embrittlement. The microstructural evolution of M/A constituents is synergistically governed by the first peak temperature ( T_p_1 ) and the second peak temperature ( T_p_2 ), with T_p_2 playing a dominant role. Within the temperature range of 740 °C to 780 °C, M/A constituents in the ICCGHAZ coarsen significantly and form chain-like structures distributed quasi-continuously along the prior austenite grain boundaries, thereby establishing a contiguous hydrogen-trapping network. Under these conditions, Deff reaches its minimum value, while C0 and Nt attain their maximum levels. In contrast, when T_p_2 approaches Ac1 or Ac3, the M/A constituents are more finely dispersed, which disrupts the trapping network and weakens their ability to the retardation of hydrogen diffusion, resulting in increased Deff and decreased C0 and Nt. Multivariate regression analysis further reveals that the spatial fraction of M/A constituents has a 2 to 3 times greater influence on hydrogen permeation parameters than their average size, identifying it as the dominant factor. Additionally, although the ICCGHAZ exhibits higher hardness than the CGHAZ, the peak hardness does not align with the maximum M/A volume fraction, indicating that the carbon segregation contributes to matrix softening.
