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A convenient thermal CVD route to core−shell GaP@GaN and GaN@GaP nanowires is developed. The structural analyses indicate that the nanowires exhibit a two-layer and wirelike structure. High-resolution transmission electron microscopy (HRTEM) images reveal misfit dislocation loops at the interface of the nanowires. Unusual temperature dependences of the photoluminescence (PL) intensity of GaP@GaN nanowires are observed, and they are interpreted by the piezoelectric effect induced from lattice mismatch between two semiconductor layers. In the Raman spectra of GaN@GaP nanowires, an unexpected peak at 386 cm -1 is found and assigned to a surface phonon mode.

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Partial least squares structural equation modeling (PLS‐SEM) has become a key multivariate statistical modeling technique that educational researchers frequently use. This paper reviews the uses of PLS‐SEM in 16 major e‐learning journals, and provides guidelines for improving the use of PLS‐SEM as well as recommendations for future applications in e‐learning research. A total of 53 articles using PLS‐SEM published in January 2009–August 2019 are reviewed. We assess these published applications in terms of the following key criteria: reasons for using PLS‐SEM, model characteristics, sample characteristics, model evaluations and reporting. Our results reveal that small sample size and nonnormal data are the first two major reasons for using PLS‐SEM. Moreover, we have identified how to extend the applications of PLS‐SEM in the e‐learning research field.

A polycaprolactone (PCL) nanofibrous composite matrix having mesoporous bioactive glass nanoparticles (MBG) was fabricated using the electrospinning method, and the microstructural, physical and biological properties of the composite matrix were characterized. The fiber diameters of PCL, 5 % MBG/PCL (5 M-PCL) and 10 % MBG/PCL (10 M-PCL) were 575 ± 162 nm, 312 ± 134 nm and 321 ± 144 nm, respectively. The bioactivity of the composite matrix was evaluated by soaking the matrix in 1.5× simulated body fluid; the MBG/PCL matrix showed a better biomineralization capability than did the PCL matrix. The biological performance of the PCL and the MBG/PCL were evaluated using an in vitro culture of MG63 osteoblast-like cells. We found that the cell attachment and proliferation rates were significantly higher on the 10 M-PCL than on the PCL. Moreover, the expression of several genes, including ANX-V, type I collagen and OCN, ALP activity, the deposition of calcium, and the BSP protein, were also significantly higher on 10 M-PCL than PCL. These results indicated that MBG/PCL has the ability to support cell attachment, growth, and differentiation and can also yield high bioactivity. Therefore, MBG/PCL could be potentially applied in bone implants.

SUMMARYThis article presents a new vertex-to-face contact searching algorithm for the three-dimensional (3-D) discontinuous deformation analysis (DDA). In this algorithm, topology is applied to the contact rule when any two polyhedrons are close to each other. Attempt is made to expand the original contact searching algorithm from two-dimensional (2-D) to 3-D DDA. Examples are provided to demonstrate the new contact rule for vertex-to-face contacts between two polyhedrons with planar boundaries.

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Single‐crystal Sb2S3 nanotubes with chain‐like structures (see Figure) have been successfully synthesized by chemical vapor transport using sulfur as the transport agent. Detailed characterization of the nanotubes shows the growth direction of Sb2S3 nanotubes is determined by the crystallographic orientation of the chain‐like building blocks. A mechanism explaining the formation of the nanotubes is presented.