scholarly journals Oscillation and Repetitive Firing in Squid Axons

1970 ◽  
Vol 55 (1) ◽  
pp. 104-118 ◽  
Author(s):  
Rita Guttman ◽  
Robert Barnhill
Keyword(s):  
Phase Transition ◽  
Critical Temperature ◽  
Natural Frequency ◽  
Stimulus Intensity ◽  
Repetitive Firing ◽  
Time Interval ◽  
Membrane Phase ◽  
Temperature Range ◽  
Subthreshold Oscillation ◽  
Low Calcium

Space-clamped squid axons treated with low calcium and computed Hodgkin-Huxley (HH) axons were stimulated by steps of superthreshold current from 101 to 400% of the rheobasic value over a temperature range of 5–27°C. The natural frequency of sustained repetitive firing of real and computed axons depended weakly upon stimulus intensity and strongly upon temperature, with a Q10 of 2.7 (experimental) and 2.6 (computed). For real axons, but not the computed axon, the intervals between the first two spikes were shorter than between subsequent spikes. Constant spike frequencies from 75 Hz at low intensities and temperatures to 330 Hz at high intensities and temperatures were soon achieved. Subthreshold and superthreshold responses were sometimes intermixed in a train of responses from a real axon responding to a constant step of current, but not predicted by HH. The time interval following a spike was always longer than that following a subthreshold oscillation in slightly decalcified real axons, as Huxley and FitzHugh also found for computed axons. There was a bias toward spikes at the beginning of the train and toward subthreshold responses later on. Some repeated patterns were found, every second, third, or fourth response being a spike. Neither the HH equations nor the computed or experimental threshold behaviors show a critical temperature to support a membrane phase transition.

scholarly journals Cooper Pair-Like Systems at High Temperature and their Role on Fluctuations Near the Critical Temperature

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3216-3219 ◽  
Author(s):  
M. Ausloos ◽  
S. Dorbolo
Keyword(s):  
Phase Transition ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Critical Temperature ◽  
Oxygen Diffusion ◽  
Cooper Pair ◽  
Anomalous Behavior ◽  
Anomalous Effect ◽  
Linear Temperature ◽  
Ybco Sample

A logarithmic behavior is hidden in the linear temperature regime of the electrical resistivity R(T) of some YBCO sample below 2T c where "pairs" break apart, fluctuations occur and "a gap is opening". An anomalous effect also occurs near 200 K in the normal state Hall coefficient. In a simulation of oxygen diffusion in planar 123 YBCO, an anomalous behavior is found in the oxygen-vacancy motion near such a temperature. We claim that the behavior of the specific heat above and near the critical temperature should be reexamined in order to show the influence and implications of fluctuations and dimensionality on the nature of the phase transition and on the true onset temperature.

Critical constants and density dependence of the Lorenz–Lorentz coefficient for germane

1978 ◽  
Vol 56 (9) ◽  
pp. 1140-1141 ◽  
Author(s):  
P. Palffy-Muhoray ◽  
D. Balzarini
Keyword(s):  
Critical Temperature ◽  
Density Dependence ◽  
Experimental Error ◽  
Critical Density ◽  
Coexistence Curve ◽  
Index Of Refraction ◽  
Density Range ◽  
Temperature Range ◽  
Critical Constants

The index of refraction at 6328 Å has been measured for germane in the density range 0.15 to 0.9 g/cm3. The temperature and density ranges over which measurements are made are near the coexistence curve. The coefficient in the Lorenz–Lorentz expression, [Formula: see text], is constant to within 0.5% within experimental error for the temperature range and density range studied. The coefficient is slightly higher near the critical density. The critical density is measured to be 0.503 g/cm3. The critical temperature is measured to be 38.92 °C.

NQR and Crystal Structure of 4,5-Dichloroimidazole, C3H2N2Cl2

1992 ◽  
Vol 47 (1-2) ◽  
pp. 177-181 ◽  
Author(s):  
Shi-Qi Dou ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Unit Cell ◽  
Space Group ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Group D

AbstractThe two line 35Cl NQR spectrum of 4,5-dichloroimidazole was measured in the temperature range 77≦ T/K ≦ 389. The temperature dependence of the NQR frequencies conforms with the Bayer model and no phase transition is indicated in the curves v ( 35Cl)= f(T). Also the temperature coefficients of the 35Cl NQR frequencies are "normal". At 77 K the 35Cl NQR frequencies are 37.409 MHz and 36.172 MHz and at 389 K 35.758 MHz and 34.565 MHz. The compound crystallizes at room temperature with the tetragonal space group D44-P41212, Z = 8 molecules per unit cell; at 295 K : a = 684.2(5) pm, c = 2414.0(20) pm. The relations between the crystal structure and the NQR spectrum are discussed.

Structural-phase transition in (Cu2Te)2−x(ZnTe)x at high temperature

2021 ◽  
pp. 2150113
Author(s):  
H. B. Gasimov ◽  
R. M. Rzayev
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
High Temperature ◽  
Single Crystals ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Xrd Study ◽  
Xrd Method

Cu2Te single crystal was grown by the Bridgman method. X-ray diffraction (XRD) study of Cu2Te single crystals in the temperature range of 293–893 K was performed and possible phase transitions in the mentioned range of temperature have been investigated. (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals also were grown with [Formula: see text], 0.05, 0.10 concentrations and structural properties of the obtained single crystals were investigated by the XRD method in the temperature range 293–893 K. Lattice parameters and possible phase transitions in the mention temperature range were determined for (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals for [Formula: see text], 0.05, 0.10 concentrations.

scholarly journals FTIR Spectra of n-Octanol in Liquid and Solid States

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
A. Vasileva ◽  
P. Golub ◽  
I. Doroshenko ◽  
V. Pogorelov ◽  
V. Sablinskas ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Phase ◽  
Temperature Dependence ◽  
Ftir Spectra ◽  
Ftir Spectrum ◽  
Structure Transformation ◽  
Temperature Range ◽  
Solid States

The investigation of the temperature dependence of FTIR spectrum of n-octanol in the temperature range from −150°C to 50°C is presented. The observed changes in the registered spectra during gradual heating of the sample were analysed. The structure transformation at the phase transition from solid to liquid phase is detected.

Nematic-Smectic a Phase-Transition Under Shear Flow

1989 ◽  
Vol 177 ◽  
Author(s):  
R. F. Bruinsma ◽  
C. R. Safinya
Keyword(s):  
Phase Transition ◽  
Critical Temperature ◽  
Shear Flow ◽  
Structure Factor ◽  
Deborah Number ◽  
Flow Properties ◽  
Newtonian Flow ◽  
One Dimensional ◽  
Smectic A ◽  
Smectic A Phase

ABSTRACTWe discuss the effect of shear flow on the nematic to smectic A phase transition. The non-Newtonian flow properties (shear thinning and normal stress) ire correlated with the distortions of the structure-factor S(q). As a function of the Deborah number, we find first a deformation of S(q) and, beyond a critical Deborah number, highly distorted, one-dimensional fluctuations. The suppression of fluctuations by shear flow raises the critical temperature.

scholarly journals Holographic Lifshitz superconductors with Weyl correction

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Jun-Wang Lu ◽  
Ya-Bo Wu ◽  
Bao-Ping Dong ◽  
Yu Zhang
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Critical Temperature ◽  
Numerical Method ◽  
Analytical Methods ◽  
Competitive Effects ◽  
Lifshitz Black Hole ◽  
The Difference ◽  
Lower Temperature ◽  
Numerical And Analytical Methods

AbstractAt the probe approximation, we construct a holographic p-wave conductor/superconductor model in the five-dimensional Lifshitz black hole with the Weyl correction via both numerical and analytical methods, and study the effects of the Lifshitz parameter z as well as the Weyl parameter $$\gamma $$ γ on the superconductor model. As we take into account one of the two corrections separately, the increasing z ($$\gamma $$ γ ) inhibits(enhances) the superconductor phase transition. When the two corrections are considered comprehensively, they display the obviously competitive effects on both the critical temperature and the vector condensate. In particular, the promoting effects of the Weyl parameter $$\gamma $$ γ on the critical temperature are obviously suppressed by the increasing Lifshitz parameter. Meanwhile, in the case of $$z<2.35$$ z < 2.35 ($$z>2.35$$ z > 2.35 ), the condensate at lower temperature decreases(increases) with the increasing Weyl parameter $$\gamma $$ γ . What is more, the difference among the condensate with the fixed Weyl parameter($$\gamma =-\frac{6}{100},0,\frac{4}{100}$$ γ = - 6 100 , 0 , 4 100 ) decreases(increases) with the increasing Lifshitz parameter z in the region $$z<2.35$$ z < 2.35 ($$z>2.35$$ z > 2.35 ). Furthermore, the increasing z obviously suppresses the real part of conductivity for all value of the Weyl parameter $$\gamma $$ γ . In addition, the analytical results agree well with the ones from the numerical method.

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