Search

A silicone rubber foam is prepared by introducing polydiborosiloxane (PDBS) into silicone rubber, and using expandable microspheres as blowing agents. The influences of the dual network structure with dynamic cross-linking network on the silicone rubber foam is characterized by the cell size, mechanical properties and impact resistance. The cell size increases from 77 to 93 [micro]m due to the introduction of a dynamic cross-linking network which reduces foaming resistance. The elongation at break elevates from 277% to 574%, and the yield strength gradually decreases. The dynamic cross-linking network also enhances the internal damping characteristic and energy absorption capacity of the foam. The impact resistance of silicone rubber foam is improved because of the synergistic effect of the dual network structure and the bubble structure. The research improves the performance of silicone rubber foam. KEYWORDS anti-impact, dynamic cross-linking, polydiborosiloxane, silicone rubber Highlights * The dual network structure to improve the mechanical properties. * Excellent cell is obtained using expandable microspheres as foaming agent. * The toughness and elongation are enhanced by regulating the molecular structure. * The dual network structure ameliorates the damping and energy absorption. * Dynamic cross-link and expandable microspheres increase the impact resistance., 1 | INTRODUCTION Silicone rubber as a polymer elastomer is extensively used in various field due to its excellent thermal stability, (1) mechanical property, (2) biocompatibility, and radiation resisting property. [...]

All-liquid molding can be used to transform a liquid into free-form solid constructs, while maintaining internal fluidity. Traditional biological scaffolds, such as cured pre-gels, are normally processed in solid state, sacrificing flowability and permeability. However, it is essential to maintain the fluidity of the scaffold to truly mimic the complexity and heterogeneity of natural human tissues. Here, this work molds an aqueous biomaterial ink into liquid building blocks with rigid shapes while preserving internal fluidity. The molded ink blocks for bone-like vertebrae and cartilaginous-intervertebral-disc shapes, are magnetically manipulated to assemble into hierarchical structures as a scaffold for subsequent spinal column tissue growth. It is also possible to join separate ink blocks by interfacial coalescence, different from bridging solid blocks by interfacial fixation. Generally, aqueous biomaterial inks are molded into shapes with high fidelity by the interfacial jamming of alginate surfactants. The molded liquid blocks can be reconfigured using induced magnetic dipoles, that dictated the magnetic assembly behavior of liquid blocks. The implanted spinal column tissue exhibits a biocompatibility based on in vitro seeding and in vivo cultivating results, showing potential physiological function such as bending of the spinal column.

This work presents a high-sensitivity solution sensor based on a phoxonic crystal nanobeam with lateral fins. The fins improve the stability of the suspended nanobeam and its detection performance is unaffected. Acoustic–optic dual-mode cross-detection improves the detection accuracy over the single-mode method. The acoustic and optical energies are concentrated in the defect and slot regions due to the combination of the gradient cavity and slot, which enhances the acoustic–optic interaction with the object to be measured, improving the detection sensitivity. Using the mode bandgaps of photonic and phononic crystals, the sensing characteristics are investigated using the finite element method. The impact of various concentrations on the transmission spectra of optical electromagnetic waves and acoustic elastic waves is investigated. The maximum sensitivity is 2149.5 kHz/ms−1, with Q of over 105 in the acoustic mode and 457.1 nm/RIU in the optical mode. The proposed nanobeam cavity with lateral fins can be used to realize miniaturized multi-mode acoustic–optic sensors. It also provides mechanical support, thermal transport, and channels for lateral carrier injection for the suspended nanobeam. [ABSTRACT FROM AUTHOR]

Deciduous woody plants like poplar (Populus spp.) have seasonal bud dormancy. It has been challenging to simultaneously delay the onset of bud dormancy in the fall and advance bud break in the spring, as bud dormancy, and bud break were thought to be controlled by different genetic factors. Here, we demonstrate that heterologous expression of the REVEILLE1 gene (named AaRVE1) from Agave (Agave americana) not only delays the onset of bud dormancy but also accelerates bud break in poplar in field trials. AaRVE1 heterologous expression increases poplar biomass yield by 166% in the greenhouse. Furthermore, we reveal that heterologous expression of AaRVE1 increases cytokinin contents, represses multiple dormancy-related genes, and up-regulates bud break-related genes, and that AaRVE1 functions as a transcriptional repressor and regulates the activity of the DORMANCY-ASSOCIATED PROTEIN 1 (DRM1) promoter. Our findings demonstrate that AaRVE1 appears to function as a regulator of bud dormancy and bud break, which has important implications for extending the growing season of deciduous trees in frost-free temperate and subtropical regions to increase crop yield.

Objective The Huayingshan fault zone, the largest fault zone within Sichuan Basin, exhibits notable differences in geological structures on both sides. Historically, earthquakes with a magnitude of ≤5 have occurred frequently along this fault zone, which remains relatively active to this day, disturbing the crustal stress field of the basin. Clarifying the crustal stress state of the Huayingshan fault zone can enhance our understanding of its active deformation and its tectonic and seismic activities and serve as a reference for subsequent research regarding this fault zone. Currently, geostress studies in this area rely mainly on analyzing seismic data, whereas the investigation of borehole data remains relatively scarce. Methods We collected and collated imaging data regarding borehole collapse and borehole-induced tensile fractures from eight borehole logging sites in the southern segment of the Huayingshan fault zone; the geostress directions of these eight boreholes were determined by analyzing these data. Subsequently, a comprehensive analysis of the geostress characteristics was performed by combining the data regarding China’s modern stress field and the earthquake focal mechanism solutions in the southeastern margin of Sichuan Basin. Results The maximum horizontal principal stress in four boreholes located in the southern region of the southern segment of the Huayingshan fault zone was oriented in the NWW-SEE direction, which aligns with the regional stress field direction in Sichuan Basin; only one borehole in the southern region exhibited a maximum horizontal principal stress in the NEE—SWW direction, representing a counterclockwise deviation relative to the regional stress field of Sichuan Basin. Meanwhile, the maximum horizontal principal stress in all three boreholes in the central region of the southern segment of the Huayingshan fault zone was also oriented in the NEE—SWW direction, representing a counterclockwise deviation relative to the regional stress field of Sichuan Basin. Conclusion Through the comprehensive analysis of the above results and the tectonic features and basement properties of the study area, the following conclusions are drawn: (1) The deviations in stress direction in the southern segment of the fault zone are primarily caused by the combined effects of changes in the basement properties of the region, tectonic stress near the boreholes, and the regional stress field. (2) The geostress characteristics obtained in the present study, along with the focal mechanism solutions of earthquakes in the southern segment of the Huayingshan fault zone, indicate that the stress direction in the southeastern margin of Sichuan Basin is relatively divergent, resulting from the combined effects of complex local structures and the regional stress field in this region. Significance The present study aims to supplement the geostress data regarding the southern segment of the Huayingshan fault zone based on borehole data, analyze the current stress field state of the rock mass, and determine the direction of the maximum horizontal principal stress. These findings will provide supporting geostress data for subsequent research on the frequent seismic activities in this region.