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The La₂FeCoO₆ ceramic was synthesized via the sol–gel route, and their temperature-dependent exchange bias (EB) effects have been analyzed at different magnetic fields. XRD investigation reveals that at a lower temperature, the monoclinic structure with the P2₁/n space group was maintained, whereas, from room temperature to 450 K, the rhombohedral structure with the R3c space group was noticed. The tolerance factor suggested the presence of distortion, and the XPS analysis of Fe and Co confirms the defect sites in La₂FeCoO₆. Hence, the variety of magnetic phases formed during the FC and ZFC processes resulted in unidirectional anisotropy. Negative field cooling magnetization was observed in M-T measurements, and ferromagnetic clusters were detected at room temperature M-H measurements. Negative EB fields and upward shifts in hysteresis were observed at low temperatures. The hysteresis and EB fields changed below the Neel transition, with a transition from positive to negative EB observed with increasing magnetic field and temperature. The observed EB was attributed to the pinning effect of surface spins in interfacial frozen glassy states at the interface of large ferrimagnetic grains.

Feistel structure is a fundamental symmetric cryptographic primitive. In this paper, we investigate the security of 5-round Feistel structure and generalized Feistel scheme (GFS) in a quantum environment and propose a family of quantum claw-finding attacks in both Q1 and Q2 models. The quantum attack uses claw-finding algorithm with the period function’s approximate promise. By employing the constructed functions g and h as inputs for claw-finding algorithm, secret information can be extracted. The attack on 5-round Feistel structure in Q1 model, which is easier to implement than Q2 model, enriched the diversity of the attack scenarios. The attacks on 5-round Feistel structure, Type-I, Type-II, and Type-III GFS in Q2 model, exhibit an exponentially lower product indicator for quantum and classical query complexity. The strongest reduction occurs in attacks on Type-I and Type-II GFS, decreasing from (2^{4n}) to (2^{2n}).

Ceftaroline (CFT) effectively combats methicillin-resistant Staphylococcus aureus (MRSA) by binding to the allosteric site on penicillin-binding protein 2a (PBP2a) and activating allosteric signals that remotely open the active pocket. However, the widespread clinical use of CFT has led to specific mutations, such as N146K/E150K, at the PBP2a allosteric site, which confers resistance to CFT in MRSA by disrupting the transmission of allosteric signals. Herein, computational simulations were employed to elucidate how the mutations disrupt the transmission of allosteric signals, thereby enhancing the resistance of MRSA to CFT. Specifically, the mutations alter the salt bridge network and electrostatic environment, resulting in a dynamic setting and decreased binding affinity of CFT within the allosteric pocket. Additionally, dynamical network analysis and the identification of allosteric pathways revealed that the reduced binding affinity diminishes the propagation of allosteric signals to the active site. Further evaluations demonstrated that this diminished signaling reduces the openness of the active pocket in the mutant systems, with “gatekeeper” residues and functional loops remaining partially closed. Redocking experiments confirmed that mutations lead to decreased docking scores and unfavorable docking poses for CFT within the active pocket. These findings highlight the complex interactions between structural changes induced by mutations and antibiotic resistance, providing crucial insights for developing new therapeutic strategies against MRSA resistance.

The novel family of materials known as magneto-electro-elastic materials has promising potential applications in nanotechnology due to its exceptional energy conversion capabilities. In this work, the different aspects of the fractional nonlinear longitudinal wave equation describing wave phenomena in a magneto electro-elastic circular rod have been studied. The soliton solutions are obtained by advanced methods, namely, (i) generalized Arnous technique (ii) generalized multivariate exponential rational integral function approach. Under certain parameters, this research finds new solitary wave solutions, including bright, singular, combined soliton, and dark solutions. Furthermore, sensitivity analysis and chaotic behavior of this problem is also discussed by the Galilean transformation. Moreover, the 2D, time series, and Poincare mapping as powerful tools for exploring the elusive nature of chaos are presented. The research presented in this study can improve the nonlinear dynamical characteristics of a specific system and validate the efficacy of the used methodologies. Our findings provide useful insights into the intricacy of nonlinear equations, enhancing prior research on the subject through the introduction of innovative techniques and the discovery of a significant number of solutions that have wide-ranging relevance.

In recent years, the linear amplitude sweep test (LAS) and the time sweep (TS) test under dynamic shear are widely used to evaluate the damage resistance of paving asphalt. This paper attempts to demonstrate the possibility of using the LAS test as the accelerated fatigue protocol for damage resistance estimation of asphalt from perspectives of crack initiation and propagation. Both the finite element (FE) simulation and experimental work based on fracture mechanics are conducted for this purpose, followed by the verification on the traditional TS fatigue test. The FE model of the cylindrical asphalt sample is created by means of the FRANC2d/L software to identify the cracking mode under the crack propagation phase. The LAS test results show that the damage evolution behavior follows the two-phase crack growth (TPCG) model and the crack propagation is governed by mode-I cracking, which is consistent to the FE-based numerical simulation. The TS test results show that the TPCG model in the LAS protocol can be utilized to reasonably distinguish the crack initiation and propagation resistance of different asphalts. The polymer modification on asphalt can significantly improve its fatigue damage resistance.

Partial singular value decomposition (PSVD) is often used to deal with dimensionality reduction, compression and data approximation of large matrices to improve computational efficiency and simplify the analysis of complex data. In this paper, we will study the problem of PSVD of split quaternion matrix. By analyzing the structure of the real representation matrix, we find that it can preserve the partially unitary property. Based on the property of the real representation matrix, we propose split quaternion partial singular value decomposition (SQPSVD) and Lanczos algorithm of SQPSVD. In numerical examples, we verify the effectiveness of the Lanczos algorithm and propose the split quaternion color image model to apply the Lanczos algorithm to color image processing. The combination of the model and algorithm has a good performance in low rank approximation of color images, color face reconstruction and recognition. Moreover, based on the Lanczos algorithm, we propose the denoising algorithm for the space magnetic field measurement data and the experimental result shows the effectiveness of the denoising algorithm.

Sand mining activities in the Mekong Delta river have caused localized erosion holes, altering the once stable flow patterns. Additionally, mining conducted too close to the riverbanks has resulted in bank instability and serious erosion issues. This study aims to evaluate the impact of sand mining on the riverbed changes, particularly the working operations of 26 sand pits along the upper reaches of the Tien River from Tan Chau to My Thuan. The results indicate that sand mining primarily affects the immediate vicinity of the mining areas, leading to heightened scouring levels and causing the mined areas in the floodplain to not fully regenerate within a year following extraction. As a result of sand mining activities, the riverbed experiences increased erosion in comparison to periods with no mining operations. The increased erosion is simulated in two sections of the Tien River, namely the Tan Chau – Hong Ngu and the segment of Tien River passing through the Gieng islet, where the highest additional erosion rates are recorded at 1.2 m/yr and 1.21 m/yr, respectively, compared to the scenario without sand mining. The simulation results also indicate that accretion from the mining sites almost returns to its original state in the segment of the Tien River passing through Sa Dec. However, the recovery of other mining sites in lower areas is significantly less. The findings of this study provide important implications for sand mining planning and natural disaster management, especially concerning erosion control measures.

Consider the Cauchy problem of the Navier–Stokes equations in (mathbb {R}^n (n ge 2)) with the initial data (a in dot{B}^{-1+n/p}_{p, infty }) for (n< p < infty ). We establish the Gevrey type estimates for the error between the successive approximations ({u_j}_{j=0}^{infty }) and the strong solution u provided the convergence in the scaling invariant norm in (L^q(mathbb {R}^n)) with the time weight holds. It is also clarified that the convergence rate of the higher order approximation is at least the same as that of the lower order approximation. In addition, the approximation for the pressure is also established.