Helical carbon nanotubes (HCNTs) with different geometrical properties were constructed and incorporated into nanocomposites for the investigation of the anti-crack mechanism. The interfacial mechanical properties of the nanocomposites reinforced with straight carbon nanotubes and various types of HCNTs were investigated through the pullout of HCNTs in the crack propagation using molecular dynamics (MD). The results show that the pullout force of HCNTs is much higher than that of CNTs because the physical interlock between HCNTs and matrices is much stronger than the van der Waals (vdW) interactions between CNTs and matrices. Remarkably, HCNTs with a large pitch length can not only effectively prevent the initiation of breakages but also hinder the growth of cracks, while HCNTs with a small diameter and tube radius cannot even effectively prevent the initiation of cracks, which is similar to straight CNTs. Moreover, the shear resistance of HCNTs increases with the increase in the helix angle, which remains at a high level when the helix angle reaches the critical value. However, HCNTs with a small helix angle and large diameter can carry out more polymer chains, while snake-like HCNTs and HCNTs with a small diameter and helix angle can hardly carry out any polymer chain during the pullout process and show similar interfacial properties to the straight CNTs.
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http://dx.doi.org/10.3390/nano15020119 | DOI Listing |
Materials (Basel)
January 2025
College of Intelligent Manufacturing, Huanghuai University, Zhumadian 463000, China.
Friction-stir-welded dissimilar AA2024/AA7075 joints have an apparent influence on grain and texture development at the weld interface due to differences in physical and chemical properties between the two aluminum alloys. In this work, the effect of tool shoulder profile on grain structure and texture evolution in the center interface zone (CIZ) and bottom interface zone (BIZ) of dissimilar AA2024/AA7075 joints were quantitatively studied by electron back-scattering diffraction (EBSD). The results indicate that abundant fine and coarse equiaxial grains are produced in the CIZ and BIZ of the joints produced with a concentric circle shoulder (CCS) and three-helix shoulder (THS), and the average grain size of the BIZ is lower than that of the CIZ for the same CCS or THS joint.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Department of Architecture and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Hong Kong.
Helical carbon nanotubes (HCNTs) with different geometrical properties were constructed and incorporated into nanocomposites for the investigation of the anti-crack mechanism. The interfacial mechanical properties of the nanocomposites reinforced with straight carbon nanotubes and various types of HCNTs were investigated through the pullout of HCNTs in the crack propagation using molecular dynamics (MD). The results show that the pullout force of HCNTs is much higher than that of CNTs because the physical interlock between HCNTs and matrices is much stronger than the van der Waals (vdW) interactions between CNTs and matrices.
View Article and Find Full Text PDFMol Phys
March 2024
Department of Physics, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States.
The stability of proteins and small peptides depends on the way they interact with the surrounding water molecules. For small peptides, such as -helical polyalanine (polyALA), water molecules can weaken the intramolecular hydrogen-bonds (HB) formed between the peptide backbone O and NH groups which are responsible for the -helix structure. Here, we perform molecular dynamics simulations to study the hydration of polyALA, polyserine (polySER), and other homopolymer peptide -helices at different temperatures and pressures.
View Article and Find Full Text PDFJ Craniofac Surg
November 2024
Department of Computer Technology and Information Systems, Erdemli School of Applied Technology and Management, Mersin University, Mersin, Turkey.
The aim of the study is to comprehensively examine the composition and localization of the auricle in formalin-fixed human fetuses during the second and third trimesters of the antenatal period. Ninety-seven auricles were evaluated (33 females and 31 males in the second, and 22 females and 11 males in the third trimester). Nine morphometric dimensions were directly measured from auricles.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
School of Mechanical & Vehicle Engineering, Linyi University, Linyi, Shandong 276000, China.
Molecular dynamics simulations demonstrate that regular conical helices of poly(-phenylene) (PPP) chains can be constructed inside the confined space of single-walled carbon nanocones (CNCs). The translocation displacement of the PPP chain combined with the change of the system total potential energy including each energy component and structural parameters of the formed conical helix is discussed to deeply explore the microstructure evolution, driving forces and dynamic mechanisms. In addition, the influence of chain length, cone angle, temperature, chain number, linked position of benzene rings and the form of Lennard-Jones potential on the helical encapsulation is further studied.
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