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A new type of stepwise radial metamaterial (SRM) with ultralow-frequency and broadband characteristics is proposed in this study. In contrast to the traditional radial metamaterial (TRM), the proposed structure is periodically arranged in a stepwise shape along the radial direction. The propagation characteristics of Lamb waves in the SRM were investigated using the finite element method. For the numerical analysis, the degeneracy between the bands of the SRM was separated, resulting in the opening of the bandgaps in the ultralow-frequency range. The total bandwidth was 75 times that of the TRM, and the wave attenuation ability was increased by more than 70%. The introduction of a stepwise array in the SRM opened up the local resonance and Bragg scattering bandgaps, and as a result, the SRM exhibited ultralow-frequency broadband characteristics. Furthermore, the influences of the structural parameters of the SRM on the bandgap characteristics were discussed. With the increase in the stepped angle, the coupling relationship between the Lamb wave mode and the local resonance was enhanced, which caused the band structure to shift to a lower frequency. In addition, the hole rotation and shape played important roles in the bandgap tuning. Finally, the experimental sample was processed based on the model, and the vibration propagation characteristics were tested to prove its ultralow-frequency broadband characteristics. The proposed shielding approach could provide a better alternative in the field of ultralow-frequency noise reduction and vibration reduction. [ABSTRACT FROM AUTHOR]

Background and Purpose: Structuring scaffold with both osteogenic and angiogenesis capabilities is a challenge for bone tissue engineering. Powder structured Si-CaP materials have shown excellent osteogenic properties and induction of stem cell differentiation. Our research group have successful produced 3D printed Si-CaP scaffolds by DLP technology. This study aims to explore the angiogenic effects of SiO32- and Ca2+ released by 3D printed Si-CaP scaffold, and whether there is a synergistic effect between the two ions. Methods: The 3D printed Si-CaP scaffolds were immersed in endothelial cell medium solution for 24 h. The Si, Ca ion released was detected by Inductively coupled plasma–optical emission spectrometry. We used detected data as a standard to prepare the simulated solution to investigate the effect of SiO32-, Ca2+ separately. Experiment was divided into control group, Si ion group, Ca ion group and Si + Ca ion group. We evaluated different ionic effect on HUVECs viability, proliferation, migration, gene expression, and tube formation on different groups. Results: The concentration of SiO32- was detected as 15.71 ± 0.04 μg/mL, Ca2+ as 67.14 ± 0.95 μg/mL. Na2SiO3 and CaCl2 were used to prepare the simulated solution. There were no statistically difference between simulated solution from ion released by scaffold. Si + Ca group promoted the gene expression significantly compared with the control group, p <.01. Expression of vascular-associated protein in Si + Ca ion group was higher than that in Si ion group, Ca ion group and control group. Si + Ca ion group significantly enhanced endothelial cell on migration and tube formation assay. Conclusion: The 3D printed Si-CaP scaffold can release effective physiological concentrations of Si, Ca ions. Si and Ca ions have a synergistic effect on promoting angiogenesis of HUVECs. 3D printed Si-CaP scaffold is promising in vascularized bone tissue engineering application. [ABSTRACT FROM AUTHOR]

Aiming at the contradictory problem that the hotels’ daily excess ingredient causes a lot of losses, which is contradictory to the profit purpose of ingredient, this paper establishes kernel model and Extensible model through Extensible theory methods combined with mind mapping. Through evaluating the characteristics of alike relative matter-element, making up comprehensive dependent functions and using Extensible transformation, we can get various solutions. And then, taking the matter-element characteristics as evaluation criteria, we can carry out the superiority evaluation to the solutions and finally get the superior solution.

With the development of society and economy, there is a new way of marketing research by people’s taking photos of the respondents. They can get paid after finishing the survey tasks by taking photos. However, the contradictory problem is that, as for the project leader, the well pay makes him spend too much money while the poor pay causes low task completion rate. The solution to the problem is to put forward a way to find the best marketing plan of the project, which can both meet the demands of marketing research and reduce the budget. By means of Extenics in combination with extensible mind mapping, we find the best marketing plan for it.