Shape Evolution and Growth Mechanisms of 3D-printed Nanowires

2021 ◽  
pp. 102076
Author(s):  
Robert Winkler ◽  
Jason D. Fowlkes ◽  
Philip D. Rack ◽  
Gerald Kothleitner ◽  
Harald Plank
Keyword(s):  
Shape Evolution ◽  
Growth Mechanisms ◽  
3D Printed

SHAPE EVOLUTION IN ONE-DIMENSIONAL ZnO NANOSTRUCTURES GROWN FROM ZnO NANOPOWDER SOURCE: VAPOR–LIQUID–SOLID VERSUS VAPOR–SOLID GROWTH MECHANISMS

2011 ◽  
Vol 10 (01n02) ◽  
pp. 75-79 ◽  
Author(s):  
SOUMEN DHARA ◽  
P. K. GIRI
Keyword(s):  
Growth Mechanism ◽  
Growth Temperature ◽  
Shape Evolution ◽  
Zno Nanostructures ◽  
Growth Mechanisms ◽  
Vapor Liquid Solid ◽  
One Dimensional ◽  
Zno Nanopowder ◽  
Simultaneous Growth ◽  
Vapor Liquid

Here we report on the growth and evolution of ZnO nanowires grown from ZnO nanopowder as a source material using a horizontal muffle furnace. The shape evolution has been studied with variation in growth temperature and zinc vapor pressure. The structural analysis on these nanostructures shows c-axis oriented aligned growth. Scanning electron microscopy imaging of these nanostructures revealed the shape evolution from nanowires to nanoribbons and then to nanorods as the growth temperature increases from 650°C to 870°C. At 650°C, only vertical nanowires have been observed and with increase in growth temperature nanowires transform to nanoribbons and then to nanorods at 870°C. And we also observed simultaneous growth of nanorods and nanoribbons under a specific growth condition. We believe that these nanowires and nanorods were formed by vapor–liquid–solid growth mechanism (catalyst-mediated growth), whereas nanoribbons were grown by vapor–solid growth mechanism (without the aid of a metal catalyst). We observed simultaneous occurrence of vapor–liquid–solid and vapor–solid growth mechanisms at a particular growth temperature. These ZnO nanowires exhibit bound exciton related UV emission at ~379 nm, and defect-emission band in the visible region. Possible growth mechanism, shape evolution, and simultaneous growth of two types of one-dimensional ZnO nanostructures under the same growth condition are discussed.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Crystal structure images of large gold clusters and growing crystals by HRTEM

1984 ◽  
Vol 42 ◽  
pp. 428-429
Author(s):  
L.R. Wallenberg ◽  
J.-O. Bovin ◽  
G. Schmid
Keyword(s):  
Crystal Structure ◽  
Nucleation And Growth ◽  
Close Packing ◽  
Gold Clusters ◽  
Molecular Weight Determination ◽  
Growth Mechanisms ◽  
Starting Point ◽  
Different Types ◽  
Nucleation And Growth Mechanisms ◽  
Points Of View

Metallic clusters are interesting from various points of view, e.g. as a mean of spreading expensive catalysts on a support, or following heterogeneous and homogeneous catalytic events. It is also possible to study nucleation and growth mechanisms for crystals with the cluster as known starting point.Gold-clusters containing 55 atoms were manufactured by reducing (C6H5)3PAuCl with B2H6 in benzene. The chemical composition was found to be Au9.2[P(C6H5)3]2Cl. Molecular-weight determination by means of an ultracentrifuge gave the formula Au55[P(C6H5)3]Cl6 A model was proposed from Mössbauer spectra by Schmid et al. with cubic close-packing of the 55 gold atoms in a cubeoctahedron as shown in Fig 1. The cluster is almost completely isolated from the surroundings by the twelve triphenylphosphane groups situated in each corner, and the chlorine atoms on the centre of the 3x3 square surfaces. This gives four groups of gold atoms, depending on the different types of surrounding.

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

3D Printed Models for Surgical Planning and Reconstructive Implant Design in Sphenoorbital Tumor Surgery

2016 ◽  
Vol 77 (S 02) ◽  
Author(s):  
Hassan Othman ◽  
Sam Evans ◽  
Daniel Morris ◽  
Saty Bhatia ◽  
Caroline Hayhurst
Keyword(s):  
Surgical Planning ◽  
Implant Design ◽  
Tumor Surgery ◽  
3D Printed

That which Is Unseen: A 3D-Printed Case-Based Didactic Approach to Teaching Pediatric Cerebrovascular Neurosurgery

2019 ◽  
Author(s):  
Avital Perry ◽  
Soliman Oushy ◽  
Lucas Carlstrom ◽  
Christopher Graffeo ◽  
David Daniels ◽  
...  
Keyword(s):  
3D Printed ◽  
Approach To Teaching ◽  
Case Based

Financial Systems and economic Development in the Russian Regions: A Comparative Analysis

2015 ◽  
pp. 94-108 ◽  
Author(s):  
K. Krinichansky
Keyword(s):  
Economic Development ◽  
Comparative Analysis ◽  
Financial Development ◽  
Public Debt ◽  
Fixed Capital ◽  
Russian Regions ◽  
Growth Mechanisms ◽  
Financial Systems ◽  
Debt Market ◽  
Regions Of Russia

The paper identifies and assesses the closeness of the connection between incremental indicators of the financial development in the regions of Russia with the incremental regional GDP and the investment in fixed capital. It is shown that the positioning of the region as an independent participant of public debt market matters: the regional GDP and investment in fixed capital grow more rapidly in the regions which are regularly borrowing on the sub-federal bonds market. The paper also demonstrates that the poorly developed financial system in some regions have caused the imperfection of the growth mechanisms since the economy is not able to use the financial system’s functions.

The Effect of Surface Texture on Color Appearance of 3D Printed Objects

2018 ◽  
Vol 2018 (1) ◽  
pp. 128-133
Author(s):  
Matt Ronnenberg ◽  
Susan Farnand
Keyword(s):  
Surface Texture ◽  
Color Appearance ◽  
3D Printed ◽  
Effect Of Surface
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