Experimental observation of geometric effect on the electron diffraction of quasi-one-dimensional nanostructures

One-dimensional (1D) nanostructures, such as nanowires, constitute building blocks for nanoscience and nanotechnology. Their fundamental physical properties are dictated by their crystalline structures, which are often characterized by transmission electron microscopy (TEM). Theoretically, the shape of a nanostructure can affect its electron diffraction pattern; however, for 1D nanostructures, an experimental observation of this geometric effect has not been reported. Here, we demonstrate unambiguously the first experimental observation of this geometric effect in electron diffraction from nanowires of iridium dioxide (IrO2) and lead tin telluride (Pb1-xSnxTe), which are topological semimetals and topological crystalline insulators, respectively. Grown by chemical vapor deposition, the nanowires are single-crystalline and have well defined facets with nearly rectangular cross-sections. Diffraction spot splitting was observed in electron diffraction patterns when the e-beam was not perpendicular to the major facets of the nanowires. Atomic-resolution scanning TEM studies rule out other possible origins of the splitting, including twin domains and non-uniform strain. Theoretical calculations of electron diffraction capturing the nanowire geometry show good agreement with the experimental results, including the diffraction order dependence of the peak splitting. The observation of this geometric effect offers a non-destructive approach to characterizing the thickness of the one-dimensional nanostructures. © 2023 Elsevier LtdWe thank Prof. J. Wang, Dr. D.Y. Xie, Dr. H. Sawada, and Prof. D. Muller for helpful discussions. The authors are also grateful to JEOL for taking some of the SAED patterns, Z-contrast STEM image, OBF images for us. We acknowledge the financial support from Indiana University College of Arts and Sciences (start-up support) and the U.S. National Science Foundation (ECCS-1936406, DMR-1914451 and DMR-2005096). M.C. and Y.H. acknowledge the support from Welch Foundation (C-2065-20210327). We also thank the Indiana University-Bloomington Electron Microscopy Center for access to transmission electron microscope and Nanoscale Characterization Facility for access to scanning electron microscope.Appendix A. Supplementary dataPeer reviewe

Youth representations of environmental protest

A necessary condition for a functioning democracy is the participation of its citizens, including its youth. This is particularly true for political participation in environmental decisions because these decisions can have intergenerational consequences. In this article we examine young people’s beliefs about one form of political participation - protest - in the context of communities affected by fracking and associated anti-fracking protest, and discuss the implications of these representations for education. Drawing on focus groups with 121 young people (age 15-19) in 5 schools and colleges near sites which have experienced anti-fracking protest in England and Northern Ireland, we find young people well-informed about avenues for formal and non-formal political participation against a background of disillusionment with formal political processes and varying levels of support for protest. We find representations of protest as disruptive, divisive, extreme, less desirable than other forms of participation, and ineffective in bringing about change but effective in awareness-raising. These representations are challenging, not least because the way protest is interpreted is critical to the way people think and act in the world. These representations of environmental protest must be challenged through formal education in order to safeguard the UN Convention on the Rights of the Child and ensure that the spirit of Article 11 of the UK Human Rights Act is protected

Multi-ancestry study of blood lipid levels identifies four loci interacting with physical activity

Many genetic loci affect circulating lipid levels, but it remains unknown whether lifestyle factors, such as physical activity, modify these genetic effects. To identify lipid loci interacting with physical activity, we performed genome-wide analyses of circulating HDL cholesterol, LDL cholesterol, and triglyceride levels in up to 120,979 individuals of European, African, Asian, Hispanic, and Brazilian ancestry, with follow-up of suggestive associations in an additional 131,012 individuals. We find four loci, in/near CLASP1, LHX1, SNTA1, and CNTNAP2, that are associated with circulating lipid levels through interaction with physical activity; higher levels of physical activity enhance the HDL cholesterol-increasing effects of the CLASP1, LHX1, and SNTA1 loci and attenuate the LDL cholesterol- increasing effect of the CNTNAP2 locus. The CLASP1, LHX1, and SNTA1 regions harbor genes linked to muscle function and lipid metabolism. Our results elucidate the role of physical activity interactions in the genetic contribution to blood lipid levels

Seismic reflections from subvertical diabase dikes in an Archean terrane: Comment and reply

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