Nonlinear Viscoelasticity Raised at Low Temperatures by Intermolecular Cooperation of Bulk Amorphous Polymers

2021 ◽  
Author(s):  
Ji-Ping Wang ◽  
Wen-Bing Hu
Keyword(s):  
Low Temperatures ◽  
Nonlinear Viscoelasticity ◽  
Amorphous Polymers

Influence of high pressure on the specific heat of amorphous polymers at low temperatures

2002 ◽  
Vol 316-317 ◽  
pp. 535-538
Author(s):  
M. Jäckel ◽  
R. Geilenkeuser ◽  
A. Gladun
Keyword(s):  
High Pressure ◽  
Specific Heat ◽  
Low Temperatures ◽  
Amorphous Polymers

BRILLOUIN SCATTERING FROM AMORPHOUS POLYMERS AT LOW TEMPERATURES

1982 ◽  
Vol 43 (C9) ◽  
pp. C9-501-C9-504
Author(s):  
M. Schmidt ◽  
R. Vacher ◽  
J. Pelous ◽  
S. Hunklinger
Keyword(s):  
Low Temperatures ◽  
Brillouin Scattering ◽  
Amorphous Polymers

Heat Capacity of Amorphous Polymers at Low Temperatures

Nature ◽  
1962 ◽  
Vol 193 (4822) ◽  
pp. 1280-1281 ◽  
Author(s):  
R. W. WARFIELD ◽  
M. C. PETREE
Keyword(s):  
Heat Capacity ◽  
Low Temperatures ◽  
Amorphous Polymers

An Investigation into the High Temperature Strength and Reinforcement of Natural Rubber

1971 ◽  
Vol 44 (3) ◽  
pp. 690-706 ◽  
Author(s):  
J. A. C. Harwood ◽  
A. R. Payne ◽  
R. E. Whittaker
Keyword(s):  
High Temperature ◽  
Natural Rubber ◽  
Low Temperatures ◽  
Energy Input ◽  
Amorphous Polymers ◽  
High Temperature Strength ◽  
Dicumyl Peroxide ◽  
Failure Properties ◽  
High Degree ◽  
Very High

Abstract The failure criterion for amorphous polymers relating hysteresis at break with energy input to failure in tensile stress-strain tests was found to be obeyed only at very high or very low temperatures in natural rubber. Tensile results between about 80° C and 130° C show a high degree of scatter, and this behavior is attributed to the ability of natural rubber to crystallize at high strains. The modification of tensile properties by the addition of carbon black in natural rubber is also discussed and compared with published results from SBR. The effect of changing the degree of crosslinking on the failure properties in both dicumyl peroxide and sulfur-cured vulcanizates of natural rubber is also considered. It is found that differences in failure properties can be accounted for by the use of a crosslinking parameter from simple rubber elasticity theory in some of the failure equations.

Interpretation of irradiation-induced changes in electron diffractograms and images of extinction contours at low temperatures

1984 ◽  
Vol 42 ◽  
pp. 268-269
Author(s):  
E. Knapek ◽  
H. Formanek ◽  
G. Lefranc ◽  
I. Dietrich
Keyword(s):  
Low Temperatures ◽  
Carbon Films ◽  
Organic Crystals ◽  
Wide Spread ◽  
Lens System ◽  
Preparation Conditions ◽  
Thin Carbon ◽  
Electron Diffractograms ◽  
Diffraction Patterns ◽  
Induced Changes

A few years ago results on cryoprotection of L-valine were reported, where the values of the critical fluence De i.e, the electron exposure which decreases the intensity of the diffraction reflections by a factor e, amounted to the order of 2000 + 1000 e/nm2. In the meantime a discrepancy arose, since several groups published De values between 100 e/nm2 and 1200 e/nm2 /1 - 4/. This disagreement and particularly the wide spread of the results induced us to investigate more thoroughly the behaviour of organic crystals at very low temperatures during electron irradiation.For this purpose large L-valine crystals with homogenuous thickness were deposited on holey carbon films, thin carbon films or Au-coated holey carbon films. These specimens were cooled down to nearly liquid helium temperature in an electron microscope with a superconducting lens system and irradiated with 200 keU-electrons. The progress of radiation damage under different preparation conditions has been observed with series of electron diffraction patterns and direct images of extinction contours.

Radiation Damage of Support Films

1981 ◽  
Vol 39 ◽  
pp. 28-29
Author(s):  
H.A. Cohen ◽  
W. Chiu
Keyword(s):  
Transfer Function ◽  
Low Temperatures ◽  
Carbon Support ◽  
Contrast Transfer Function ◽  
Electron Dose ◽  
Imaging Parameters ◽  
Negative Stain ◽  
Phase Corrections ◽  
Two Parameters ◽  
Medium Dose

The goal of imaging the finest detail possible in biological specimens leads to contradictory requirements for the choice of an electron dose. The dose should be as low as possible to minimize object damage, yet as high as possible to optimize image statistics. For specimens that are protected by low temperatures or for which the low resolution associated with negative stain is acceptable, the first condition may be partially relaxed, allowing the use of (for example) 6 to 10 e/Å2. However, this medium dose is marginal for obtaining the contrast transfer function (CTF) of the microscope, which is necessary to allow phase corrections to the image. We have explored two parameters that affect the CTF under medium dose conditions.Figure 1 displays the CTF for carbon (C, row 1) and triafol plus carbon (T+C, row 2). For any column, the images to which the CTF correspond were from a carbon covered hole (C) and the adjacent triafol plus carbon support film (T+C), both recorded on the same micrograph; therefore the imaging parameters of defocus, illumination angle, and electron statistics were identical.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

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