X‐ray study of the rotator phase of paraffins (IV): C27H56, C28H58, C29H60, C30H62, C32H66, and C34H70

1984 ◽  
Vol 80 (4) ◽  
pp. 1647-1651 ◽  
Author(s):  
J. Doucet ◽  
I. Denicolò ◽  
A. F. Craievich ◽  
C. Germain
Keyword(s):  
X Ray ◽  
Rotator Phase

A near-ambient-temperature-control cell for use with synchrotron X-ray powder diffraction

1995 ◽  
Vol 28 (5) ◽  
pp. 651-653 ◽  
Author(s):  
R. J. Cernik ◽  
S. R. Craig ◽  
K. J. Roberts ◽  
J. N. Sherwood
Keyword(s):  
Powder Diffraction ◽  
Temperature Control ◽  
Low Cost ◽  
Control Cell ◽  
Temperature Stability ◽  
Free Rotation ◽  
Melting Points ◽  
X Ray ◽  
Rotator Phase ◽  
Better Than

A low-cost cell has been designed and built for synchrotron X-ray powder diffraction studies of materials with low melting points. The cell has been operated between 253 and 323 K with a temperature stability of better than 0.1 K. The construction of the cell allows free rotation of the sample during a scan in order to maximize the number of powder grains in the reflecting position. The cell has been used to study a transition from an ordered to a rotator phase in hexadecane occurring at 278 K and the results from that study are reported.

ChemInform Abstract: X-RAY STUDY OF THE ROTATOR PHASE OF PARAFFINS. IV. C27H56, C28H58, C29H60, C30H62, C32H66, AND C34H70

1984 ◽  
Vol 15 (22) ◽  
Author(s):  
J. DOUCET ◽  
I. DENICOLO ◽  
A. F. CRAIEVICH ◽  
C. GERMAIN
Keyword(s):  
X Ray ◽  
Rotator Phase

scholarly journals Surface Crystallization and Thin Film Melting in Normal Alkanes

1994 ◽  
Vol 366 ◽  
Author(s):  
X. Z. Wu ◽  
H. H. Shag ◽  
B. M. Ocko ◽  
M. Deutsch ◽  
S. K. Sinha ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Carbon Number ◽  
Grazing Incidence ◽  
Melting Behavior ◽  
Surface Crystallization ◽  
Surface Phase ◽  
Normal Alkanes ◽  
X Ray ◽  
Rotator Phase ◽  
Surface Freezing

ABSTRACTNormal alkanes of carbon number n>14 exhibit surface crystallization at their liquid-vapor interface. This has been investigated with x-ray reflectivity, grazing incidence scattering and surface tension measurements. The structure and thermodynamics of the surface layer is consistent with a monolayer of the bulk rotator phase occurring at the surface above the bulk melting temperature. On the other hand, thin films of alkanes on SiO2, exhibit a reduction of the melting temperature. The surface crystalline phase is observed for carbon number n>14. The vanishing of surface phase for small n may be due to a transition from surface freezing to surface melting behavior. These measurements can yield the relative surface energies of the various phases.

The Rotator Phases of the Normal Alkanes

1991 ◽  
Vol 248 ◽  
Author(s):  
E. B. Sirota ◽  
H.E. King ◽  
D.M. Singer ◽  
H. Shao
Keyword(s):  
Order Parameters ◽  
Normal Alkanes ◽  
X Ray ◽  
X Ray Scattering ◽  
Rotator Phase ◽  
Scattering Study ◽  
Ray Scattering

AbstractWe present results of an x-ray scattering study on the rotator phases of normal alkanes: CH2-(CH3)n-CH2 (20 ≤ ≤ 33). We have characterized a new tilted rotator phase and measured the distortion and tilt order parameters in all 5 rotator phases. We have shown that there is no strong even-odd chain effect within the rotator phases.

X‐ray study of the ‘‘rotator’’ phase of the odd‐numbered paraffins C17H36, C19H40, and C21H44

1981 ◽  
Vol 75 (3) ◽  
pp. 1523-1529 ◽  
Author(s):  
J. Doucet ◽  
I. Denicolo ◽  
A. Craievich
Keyword(s):  
X Ray ◽  
Rotator Phase

scholarly journals X-ray study of the rotator phase ofn-alkanes

1981 ◽  
Vol 37 (a1) ◽  
pp. C364-C364
Author(s):  
J. Doucet ◽  
I. Denicoló ◽  
A. F. Craievich
Keyword(s):  
X Ray ◽  
Rotator Phase

Observation of the Transient Rotator Phase ofn-Hexadecane in Emulsified Droplets with Time-Resolved Two-Dimensional Small- and Wide-Angle X-Ray Scattering

2005 ◽  
Vol 94 (9) ◽  
Author(s):  
Yuya Shinohara ◽  
Naohiko Kawasaki ◽  
Satoru Ueno ◽  
Isao Kobayashi ◽  
Mitsutoshi Nakajima ◽  
...  
Keyword(s):  
Wide Angle ◽  
Two Dimensional ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Rotator Phase ◽  
Ray Scattering

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

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