Fractal properties of polymer crystals

1989 ◽  
Vol 90 (3) ◽  
pp. 2063-2067 ◽  
Author(s):  
Tetsuya Ogawa ◽  
Satoru Miyashita ◽  
Hideki Miyaji ◽  
Shoji Suehiro ◽  
Hisao Hayashi
Keyword(s):  
Polymer Crystals ◽  
Fractal Properties

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

Shot-noise simulations of HREM images of polymer crystals

1989 ◽  
Vol 47 ◽  
pp. 342-343
Author(s):  
Philippe Pradère ◽  
Edwin L. Thomas
Keyword(s):  
Low Dose ◽  
Molecular Level ◽  
High Resolution Electron Microscopy ◽  
Crystal Defects ◽  
Inorganic Materials ◽  
Photographic Emulsion ◽  
Polymer Crystals ◽  
Resolution Electron ◽  
Recent Developments ◽  
Lattice Images

High Resolution Electron Microscopy (HREM) is a very powerful technique for the study of crystal defects at the molecular level. Unfortunately polymer crystals are beam sensitive and are destroyed almost instantly under the typical HREM imaging conditions used for inorganic materials. Recent developments of low dose imaging at low magnification have nevertheless permitted the attainment of lattice images of very radiation sensitive polymers such as poly-4-methylpentene-1 and enabled molecular level studies of crystal defects in somewhat more resistant ones such as polyparaxylylene (PPX) [2].With low dose conditions the images obtained are very noisy. Noise arises from the support film, photographic emulsion granularity and in particular, the statistical distribution of electrons at the typical doses of only few electrons per unit resolution area. Figure 1 shows the shapes of electron distribution, according to the Poisson formula :

Fractal properties of neurophysiologic signals in rat somatosensory cortex

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S186-S186
Author(s):  
Peter Herman ◽  
Shaun A Wahab ◽  
Andras Eke ◽  
Fahmeed Hyder
Keyword(s):  
Somatosensory Cortex ◽  
Fractal Properties ◽  
Rat Somatosensory Cortex

scholarly journals Polymer Crystals: Approaching Crystal Structure and High Electron Mobility in Conjugated Polymer Crystals (Adv. Mater. 10/2021)

2021 ◽  
Vol 33 (10) ◽  
pp. 2170075
Author(s):  
Ze‐Fan Yao ◽  
Yu‐Qing Zheng ◽  
Jin‐Hu Dou ◽  
Yang Lu ◽  
Yi‐Fan Ding ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Mobility ◽  
Conjugated Polymer ◽  
High Electron ◽  
High Electron Mobility ◽  
Polymer Crystals

Nanodiffraction Imaging of Polymer Crystals

2021 ◽  
Author(s):  
Shusuke Kanomi ◽  
Hironori Marubayashi ◽  
Tomohiro Miyata ◽  
Kenji Tsuda ◽  
Hiroshi Jinnai
Keyword(s):  
Polymer Crystals

scholarly journals Interaction of Poly L-Lactide and Tungsten Disulfide Nanotubes Studied by in Situ X-ray Scattering during Expansion of PLLA/WS2NT Nanocomposite Tubes

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1764
Author(s):  
Lison Rocher ◽  
Andrew S. Ylitalo ◽  
Tiziana Di Luccio ◽  
Riccardo Miscioscia ◽  
Giovanni De Filippo ◽  
...  
Keyword(s):  
Extrusion Direction ◽  
Tungsten Disulfide ◽  
Molding Process ◽  
X Ray ◽  
X Ray Scattering ◽  
Polymer Crystals ◽  
Neat Plla ◽  
Tube Expansion ◽  
Ray Scattering

In situ synchrotron X-ray scattering was used to reveal the transient microstructure of poly(L-lactide) (PLLA)/tungsten disulfide inorganic nanotubes (WS2NTs) nanocomposites. This microstructure is formed during the blow molding process (“tube expansion”) of an extruded polymer tube, an important step in the manufacturing of PLLA-based bioresorbable vascular scaffolds (BVS). A fundamental understanding of how such a microstructure develops during processing is relevant to two unmet needs in PLLA-based BVS: increasing strength to enable thinner devices and improving radiopacity to enable imaging during implantation. Here, we focus on how the flow generated during tube expansion affects the orientation of the WS2NTs and the formation of polymer crystals by comparing neat PLLA and nanocomposite tubes under different expansion conditions. Surprisingly, the WS2NTs remain oriented along the extrusion direction despite significant strain in the transverse direction while the PLLA crystals (c-axis) form along the circumferential direction of the tube. Although WS2NTs promote the nucleation of PLLA crystals in nanocomposite tubes, crystallization proceeds with largely the same orientation as in neat PLLA tubes. We suggest that the reason for the unusual independence of the orientations of the nanotubes and polymer crystals stems from the favorable interaction between PLLA and WS2NTs. This favorable interaction leads WS2NTs to disperse well in PLLA and strongly orient along the axis of the PLLA tube during extrusion. As a consequence, the nanotubes are aligned orthogonally to the circumferential stretching direction, which appears to decouple the orientations of PLLA crystals and WS2NTs.

Pattern analysis of fractal properties in multilayer systems with metamaterials

2016 ◽  
Vol 24 (1) ◽  
pp. 17-21 ◽  
Author(s):  
M. G. Davydova ◽  
P. V. Korolenko ◽  
S. B. Ryzhikov ◽  
Yu. V. Ryzhikova
Keyword(s):  
Pattern Analysis ◽  
Multilayer Systems ◽  
Fractal Properties
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