Exploring the underlying kinetics of electrodeposited PANI-CNT composite using distribution of relaxation times

2021 ◽  
pp. 139501
Author(s):  
Ash Stott ◽  
Décio B. de Freitas Neto ◽  
Jose M. Rosolen ◽  
Radu A. Sporea ◽  
S. Ravi P. Silva
Keyword(s):  
Relaxation Times ◽  
Kinetics Of

scholarly journals Single-sided NMR for the measurement of the degree of cross-linking and curing

2018 ◽  
Vol 7 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Norbert Halmen ◽  
Christoph Kugler ◽  
Eduard Kraus ◽  
Benjamin Baudrit ◽  
Thomas Hochrein ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Curing Kinetics ◽  
Cross Linking ◽  
Scanning Calorimetry ◽  
First Results ◽  
Non Destructive ◽  
Kinetics Of ◽  
Good Agreement

Abstract. The degree of cross-linking and curing is one of the most important values concerning the quality of cross-linked polyethylene (PE-X) and the functionality of adhesives and resin-based components. Up to now, the measurement of this property has mostly been time-consuming and usually destructive. Within the shown work the feasibility of single-sided nuclear magnetic resonance (NMR) for the non-destructive determination of the degree of cross-linking and curing as process monitoring was investigated. First results indicate the possibility of distinguishing between PE-X samples with different degrees of cross-linking. The homogeneity of the samples and the curing kinetics of adhesives can also be monitored. The measurements show good agreement with reference tests (wet chemical analysis, differential scanning calorimetry, dielectric analysis). Furthermore, the influence of sample temperature on the characteristic relaxation times can be observed.

scholarly journals Experimental Investigation of Rate-Dependent Inner Hysteresis Loops in PZT

2005 ◽  
Vol 881 ◽  
Author(s):  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Experimental Investigation ◽  
Systematic Study ◽  
Domain Switching ◽  
Piezoelectric Materials ◽  
Relaxation Times ◽  
Hysteresis Loops ◽  
Loading Rates ◽  
Rate Dependent ◽  
Realistic Modeling ◽  
Kinetics Of

AbstractThe rate-dependence of piezoelectric materials resulting from the kinetics of domain switching is an important factor that needs to be included in realistic modeling attempts. This paper provides a systematic study of the rate-dependent hysteresis behavior of a commercially available PZT stack actuator. Experiments covering full as well as minor loops are conducted at different loading rates with polarization and strain recorded. In addition, the creep behavior at different constant levels of the electric field is observed. This provides evidence of kinetics being characterized by strongly varying relaxation times that can be associated with different switching mechanisms.

scholarly journals TERAHERTZ BLOCH OSCILLATOR WITH SUPPRESSED ELECTRIC DOMAINS: EFFECT OF ELASTIC SCATTERING

2009 ◽  
Vol 23 (20n21) ◽  
pp. 4459-4472 ◽  
Author(s):  
TIMO HYART ◽  
KIRILL N. ALEKSEEV ◽  
AHTI LEPPÄNEN ◽  
ERKKI V. THUNEBERG
Keyword(s):  
Elastic Scattering ◽  
Space Charge ◽  
Relaxation Times ◽  
Electron Velocity ◽  
Thz Radiation ◽  
Charge Accumulation ◽  
Operational Conditions ◽  
Miniband Transport ◽  
Kinetics Of ◽  
Transport Approach

We theoretically consider the amplification of THz radiation in a superlattice Bloch oscillator. The main dilemma in the realization of THz Bloch oscillator is finding operational conditions which allow simultaneously to achieve gain at THz frequencies and to avoid destructive space-charge instabilities. A possible solution to this dilemma is the extended Limited Space-Charge Accumulation scheme of Kroemer (H. Kroemer, cond-mat/0009311). Within the semiclassical miniband transport approach we extend its range of applicability by considering a difference in the relaxation times for electron velocity and electron energy. The kinetics of electrons and fields establishing a stationary signal in the oscillator is also discussed.

Laser Raman temperature-jump study of the kinetics of the triiodide equilibrium. Relaxation times in the 10-8 -10-7 second range

1972 ◽  
Vol 94 (5) ◽  
pp. 1554-1559 ◽  
Author(s):  
Douglas H. Turner ◽  
George W. Flynn ◽  
Norman Sutin ◽  
James V. Beitz
Keyword(s):  
Temperature Jump ◽  
Relaxation Times ◽  
Laser Raman ◽  
Kinetics Of

scholarly journals Length Dependent Folding Kinetics of Alanine-Based Helical Peptides from Optimal Dimensionality Reduction

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 385
Author(s):  
Krzysztof Kuczera ◽  
Robert Szoszkiewicz ◽  
Jinyan He ◽  
Gouri S. Jas
Keyword(s):  
Dimensionality Reduction ◽  
Relaxation Times ◽  
Coarse Grained ◽  
Free Energies ◽  
Folding Kinetics ◽  
Helical Peptides ◽  
Peptide Conformations ◽  
Dynamical Parameters ◽  
Dynamics Simulations ◽  
Kinetics Of

We present a computer simulation study of helix folding in alanine homopeptides (ALA)n of length n = 5, 8, 15, and 21 residues. Based on multi-microsecond molecular dynamics simulations at room temperature, we found helix populations and relaxation times increasing from about 6% and ~2 ns for ALA5 to about 60% and ~500 ns for ALA21, and folding free energies decreasing linearly with the increasing number of residues. The helix folding was analyzed with the Optimal Dimensionality Reduction method, yielding coarse-grained kinetic models that provided a detailed representation of the folding process. The shorter peptides, ALA5 and ALA8, tended to convert directly from coil to helix, while ALA15 and ALA21 traveled through several intermediates. Coarse-grained aggregate states representing the helix, coil, and intermediates were heterogeneous, encompassing multiple peptide conformations. The folding involved multiple pathways and interesting intermediate states were present on the folding paths, with partially formed helices, turns, and compact coils. Statistically, helix initiation was favored at both termini, and the helix was most stable in the central region. Importantly, we found the presence of underlying universal local dynamics in helical peptides with correlated transitions for neighboring hydrogen bonds. Overall, the structural and dynamical parameters extracted from the trajectories are in good agreement with experimental observables, providing microscopic insights into the complex helix folding kinetics.

scholarly journals Kinetics of the monomer-dimer reaction of yeast hexokinase PI

1992 ◽  
Vol 287 (2) ◽  
pp. 567-572 ◽  
Author(s):  
J G Hoggett ◽  
G L Kellett
Keyword(s):  
Glucose Concentration ◽  
Relaxation Times ◽  
Kinetic Studies ◽  
Relaxation Effect ◽  
Enzyme Concentration ◽  
Diffusion Controlled ◽  
Low Concentrations ◽  
Kinetics Of ◽  
Yeast Hexokinase

Kinetic studies of the glucose-dependent monomer-dimer reaction of yeast hexokinase PI at pH 8.0 in the presence of 0.1 M-KCl have been carried out using the fluorescence temperature-jump technique. A slow-relaxation effect was observed which was attributed from its dependence on enzyme concentration to the monomer-dimer reaction; the reciprocal relaxation times tau-1 varied from 3 s-1 at low concentrations of glucose to 42 s-1 at saturating concentrations. Rate constants for association (kass.) and dissociation (kdiss.) were determined as a function of glucose concentration using values of the equilibrium association constant of the monomer-dimer reaction derived from sedimentation ultracentrifugation studies under similar conditions, and also from the dependence of tau-2 on enzyme concentration. kass. was almost independent of glucose concentration and its value (2 x 10(5) M-1.s-1) was close to that expected for a diffusion-controlled process. The influence of glucose on the monomer-dimer reaction is entirely due to effects on kdiss., which increases from 0.21 s-1 in the absence of glucose to 25 s-1 at saturating concentrations. The monomer and dimer forms of hexokinase have different affinities and Km values for glucose, and the results reported here imply that there may be a significant lag in the response of the monomer-dimer reaction to changes in glucose concentrations in vivo with consequent hysteretic effects on the hexokinase activity.

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