Short-range order in some polymer melts from X-ray diffraction

Author(s):  
J. D. Londono ◽  
A. Habenschuss ◽  
J. G. Curro ◽  
J. J. Rajasekaran
1987 ◽  
Vol 22 (12) ◽  
pp. 4357-4361 ◽  
Author(s):  
R. A. Ligero ◽  
J. Vázquez ◽  
P. Villares ◽  
R. Jimńez-Garay

2020 ◽  
Vol 56 (2) ◽  
pp. 269-277
Author(s):  
V.E. Sokol’skii ◽  
D.V. Pruttskov ◽  
O.M. Yakovenko ◽  
V.P. Kazimirov ◽  
O.S. Roik ◽  
...  

Anorthite and gehlenite crystalline structure and short-range order of anorthite melt have been studied by X-ray diffraction in the temperature range from room temperature up to ~ 1923 K. The corresponding anorthite and gehlenite phases were identified as well as amorphous component for anorthite samples having identical shape to XRD pattern of the anorthite melt. The structure factor and the radial distribution function of atoms of the anorthite melt were calculated from the X-ray high-temperature experimental data. The partial structural parameters of the short-range order of the melt were reconstructed using Reverse Monte Carlo simulations.


1981 ◽  
Vol 36 (8) ◽  
pp. 880-885 ◽  
Author(s):  
W. Hoyer ◽  
B. Kunsch ◽  
M. Suda ◽  
E. Wieser

Abstract Neutron scattering results on Se1-xTex melts (x = 0.3, 0.6, 0.8) obtained at 460 °C are combined with earlier X-ray diffraction data. The behaviour of the number and distance of nearest neighbours is discussed with respect to chemical short-range order and transition from twofold to three-fold coordination. For Se70Te30 the radial concentration correlation function 4πr2 ρcc(r) has been evaluated. It shows clearly the preferred formation of unlike pairs (Se-Te) within the chains.


2002 ◽  
Vol 71 (10) ◽  
pp. 2456-2458 ◽  
Author(s):  
Dilip Kumar Saha ◽  
Toetsu Shishido ◽  
Ken-ichi Ohshima

1990 ◽  
Vol 195 ◽  
Author(s):  
J. Weissmüller ◽  
J. Jing ◽  
A. Krämer ◽  
R. Birringer ◽  
U. Gonser ◽  
...  

ABSTRACTA new method of preparing amorphous solids is presented. X-ray diffraction, thermal stability and Mgssbauer spectroscopy give evidence for an atomic structure with reduced short–range order in Si75Auz5 and Pd72FeloSil8 alloys prepared by this method.


2002 ◽  
Vol 754 ◽  
Author(s):  
G.W. Lee ◽  
A.K. Gangopadhyay ◽  
K.F. Kelton ◽  
R.W. Hyers ◽  
T.J. Rathz ◽  
...  

ABSTRACTMaximum undercooling results for the icosahedral phase (i-phase), polytetrahedral C14 Laves phase, and solid solution phases are presented as a function of composition in Ti-Zr-Ni liquids. Containerless processing was achieved using the electrostatic levitation facility located at NASA/Marshall Space Flight Center. The maximum reduced undercooling decreases with increasing icosahedral short-range order in the ordered phase. The first synchrotron x-ray diffraction data from aerodynamically levitated liquids of Ti-Zr-Ni alloys suggest an icosahedral short-range order in the liquids, supporting Frank's hypothesis, correlating icosahedral order in the liquid with the nucleation barrier to the crystal phase. The strong negative heats of mixing between Ti/Zr and Ni and their relative atomic sizes likely favor the formation of this local icosahedral order.


1983 ◽  
Vol 38 (2) ◽  
pp. 142-148 ◽  
Author(s):  
E. Nassif ◽  
P. Lamparter ◽  
W. Sperl ◽  
S. Steeb

Abstract The total structure factors as well as the total pair correlation functions for amorphous Mg85.5Cu14.5 (by neutron and X-ray diffraction) and for amorphous Mg70Zn30 (by X-ray diffraction) were determined. Both alloys show similar chemical short range order effects. From the total pair correlation function of the Mg85.5Cu14.5 glass, partial coordination numbers and atomic distances could be extracted. Comparison with the structure of crystalline Mg2Cu suggests that the short range order around the copper atoms is similar in the amorphous and the crystalline phase. The densities of both amorphous alloys were measured yielding negative excess volumina.


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