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Objective: To analyze the research hotspots and trends of nursing scenario simulation teaching at home and abroad, and to provide reference for future nursing talent education. Methods: CNKI and Web of Science databases were searched. From the establishment of the database to April 2022, relevant literature on nursing scenario simulation teaching research at home and abroad was retrieved, and Cite Space software was used for visual analysis. Results: The research focus on China was the application and application effect of nursing scenario simulation teaching. The research hotspots abroad are the quality evaluation, reliability and influence of nursing scenario simulation teaching. Conclusion: The research and development of nursing scenario simulation teaching gradually tend to be systematic.

The micro-cracks in a material lead to a reduction in its overall strength and service life. The emerging capsule-based self-healing system provides a new strategy for repairing the cracks, effectively delaying the potential damage of the matrix, and prolonging the service life of composite materials. Determining the optimal size and dosage of microcapsules required to repair cracks in the matrix is essential for the development and design of capsule-based self-healing materials. This paper presents a novel two-dimensional capsule-based self-healing model composite material whose surface is paved by reproducible and random cells and some microcapsules are randomly dispersed in those cells to investigate the rupture behavior of microcapsules forced by growing cracks. An analytical model is proposed from the viewpoint of geometrical probability to express the probability characteristics of the embedded microcapsules stimulated by linear cracks in a two-dimensional capsule-based self-healing model composite. Additionally, the effect of the size and dosage of the embedded microcapsules on the intersection probability is analyzed, and the maximal probability is also found to improve the self-healing efficiency. Finally, the accuracies of these probability values and theoretical solutions are verified via computer simulation, and the results show that the developed model of the geometrical probability of the crack intersection with microcapsules randomly distributed in the cells of the matrix will help to provide a theoretical basis for the quantitative design of capsule-based self-healing materials.

The reinforced efficiency of steel fibers in composites is closely related to their spatial orientation, which can be generally driven by the external magnetic force and restricted by the wall effect of rigid boundaries of the container. To clarify the spatial orientation of steel fibers in composites considering the effect of rigid boundaries under the electromagnetic field, a series of two-phase models consisting of fibrous particles and homogeneous matrix are generated, in which the fibers are separately simplified as spherocylindrical, cylindrical, and linear particles. Based on these models of the semi-periodic boundaries, the effect of fiber characteristics (e.g., the fiber content V f, fiber aspect ratio ε, fiber length l sf, and fiber style) on both the spatial distribution and orientation degree of fibrous particles is studied before and after the fibers are aligned by the magnetic force. The results revealed that (1) both the effective number N A and orientation degree ξ of fibrous particles at a cross-section of the container can be greatly increased when the electromagnetic field is applied and (2) the wall effect of rigid boundaries shows an adverse impact on the amelioration of N A and ξ, and the range size of the affected region is essentially equal to the effective length of fibrous particles of different shapes (e.g., l sf + D sf) for spherocylindrical particles and l sf for cylindrical and linear particles).

The interfacial transition zone (ITZ) percolation is an effective parameter reflecting the connectivity of ITZs in cementitious materials, and its emergence may accelerate the penetration of inimical ions. In the existing literature on ITZ percolation, aggregates are generally simplified as the identical-shaped particles and the thickness of the ITZ phase around them is set to be uniform, which differs greatly from the realities and may cause the large deviation. To determine the ITZ percolation with the response of different phases in a more realistic way, a more satisfying three-dimensional (3D) polyphase model of concrete is developed, in which the convex ovoids and polyhedrons are separately adopted to represent the sands and gravels. The realistic nonuniform ITZ is also assigned for these aggregates based on their specific sizes and the W/C for the cement matrix. By coupling these models with the continuum percolation theory in statistical physics, the influence of individual phases on the global percolation threshold ϕ agg,c of ITZs is further studied by the simulation. The results reveal that the models here provide a smaller percolation threshold ϕ agg,c than the previous prediction models containing the simplistic uniform ITZs. There is reason to believe that these results in the work would be closer to the actual threshold in the realistic circumstance.

Magnesium phosphate cement (MPC), which belongs to chemically bonded phosphate ceramics, is commonly applied as a repair material and waste stabilization/solidifications. However, studies on the influence of CO2 on the phase assemblages in MPC are limited. A thermodynamic simulation approach is employed to explore the influence of CO2 on the equilibrium phase assemblage of MPC. The mechanisms of natural and enforced carbonation of MPC have been investigated in this work. The results disclose that Mg carbonates are less likely to precipitate in magnesium ammonium phosphate cement (MAPC) cured under CO2, while MgCO3·3H2O is the only carbonation product of magnesium potassium phosphate cement (MKPC). The carbonation resistance of MAPC is better than that of MKPC. The increase of activity of magnesia employed in MPC obviously enhances the formation of brucite and slightly promotes the carbonation of MPC. [ABSTRACT FROM AUTHOR]

This article presents a numerical method for determining the dosage of pre-embedded capsules in self-healing materials with complex crack patterns. The crack distribution on the surface of materials is simplified into a two-dimensional (2D) multi-shaped geometrical structure composed of triangles, rhombuses, and hexagons with specified area fractions, and further decomposed into three separate mono-shaped crack systems. Then, the dosage of capsules required to heal the cracks in each mono-shaped crack system is computed. According to the area fraction of each mono-shaped polygon in the whole system, the integrated models of crack-hitting probability by the capsules and the capsule dosage for the multi-shaped crack system are derived. The analytical results reveal that the dosage of capsules significantly depends on the spatial distribution of the cracks and the ratio of the capsule length to the crack size. For a certain fixed crack pattern, the size and dosage of capsules will strongly affect crack healing efficiency.