Negative temperature coefficients in chlorination reactions of unsaturated compounds in carbon tetrachloride

1975 ◽  
Vol 9 (3) ◽  
pp. 267-271
Author(s):  
V. P. Konyushenko ◽  
Yu. A. Serguchev ◽  
G. A. Stetsyuk
Keyword(s):  
Carbon Tetrachloride ◽  
Negative Temperature ◽  
Temperature Coefficients ◽  
Unsaturated Compounds

scholarly journals THE EFFECT OF TEMPERATURE AND OF LYSIN CONCENTRATION ON THE ACCELERATION OF HEMOLYSIS

1941 ◽  
Vol 25 (2) ◽  
pp. 247-261
Author(s):  
Eric Ponder
Keyword(s):  
Cell Surface ◽  
Quantitative Description ◽  
Negative Temperature ◽  
Effect Of Temperature ◽  
Membrane Component ◽  
Temperature Coefficients ◽  
Rate Of Escape ◽  
Point To Point ◽  
Special Case ◽  
Do So

The acceleration of saponin hemolysis by benzene, indol, and nonyl alcohol has been investigated as a function of temperature, and it has been found that these accelerators have negative temperature coefficients. This points to their being concentrated at the cell surface, and to the surface being the seat of their accelerating action. It is shown that the accelerating power of indol (used as a typical accelerator) is constant so long as the lysin in the system is capable of producing lysis per se, but that the acceleration falls off when only sublytic concentrations are present. The relations are expressed in a series of equations, and explained in terms of the reactions among the accelerator, the lysin, and the membrane component, which breaks down in spots, rather than uniformly, when lysis occurs. The argument involves a consideration of the idea that a monolayer of lysin at the cell surface is necessary for hemolysis, of Abramson's hypothesis of "key spots" on the surface, of the rate of escape of hemoglobin from the hemolyzing cell, and of the results of electrophoretic and impedance measurements. The existing theory of the kinetics is extended by introducing the idea of a variation in resistance from point to point in the cell membrane; in this form it describes the situation so far as is at present known, and shows that the results of the various methods of investigation are consistent with each other. The only idea discussed which seems to have little foundation is that lysis is determined by the formation of a monolayer of lysin at the cell surface; when this occurs, it must do so only as a special case. Finally, a semi-quantitative description of the frequency distribution of the resistances in the membrane is derived from existing data. The variation in resistance which it is necessary to assume is quite small, as might be expected in the case of a membrane with a regular ultra-structure.

Positive and negative temperature coefficients of resistance

1975 ◽  
Vol 43 (12) ◽  
pp. 1100-1101 ◽  
Author(s):  
A. G. Klein
Keyword(s):  
Negative Temperature ◽  
Temperature Coefficients

Negative-temperature coefficients of electrical resistivity in amorphous La-based alloys

1980 ◽  
Vol 22 (6) ◽  
pp. 2665-2669 ◽  
Author(s):  
R. Mueller ◽  
K. Agyeman ◽  
C. C. Tsuei
Keyword(s):  
Electrical Resistivity ◽  
Negative Temperature ◽  
Temperature Coefficients

scholarly journals On the direct determination of the electrostatic moments of molecules

1929 ◽  
Vol 124 (795) ◽  
pp. 689-698 ◽  
Keyword(s):  
Dielectric Constant ◽  
Direct Determination ◽  
Negative Temperature ◽  
Dielectric Constants ◽  
Temperature Coefficients ◽  
Different Temperatures

According to Faraday's ideas, the specific inductive capacity of a substance is due to the polarisation of the molecules as wholes. This is the basis of the old Clausius-Mosotti theory of dielectrics, on which it is shown first that the polarisation P is proportional to the polarising field, i. e. , P = k E, k being the dielectric constant, and second that δ being the density of the dielectric, k - 2/ k + 2 ·1/δ = constant. Now it is known that some substances have large negative temperature coefficients for their dielectric constants which cannot thus be accounted for. To provide for this Debye proposed the theory that the molecules were permanently polarised and that they were systematically orientated in the field. This leads to the equation k - 2/ k + 2 = a T -1 + b T -2 , to represent the change of specific inductive capacity with temperature. This theory has been developed by Gans and others, and a number of measurements have been made by Smyth and others, who have found the molecular moments of many substances by measuring the dielectric constants at different temperatures.

The Master Equation for the Dissociation of a Dilute Diatomic Gas. X. How Rotation Causes Low Arrhenius Temperature Coefficients

1973 ◽  
Vol 51 (18) ◽  
pp. 3152-3155 ◽  
Author(s):  
Huw O. Pritchard
Keyword(s):  
Low Temperature ◽  
Temperature Coefficient ◽  
Rate Constants ◽  
Recombination Rate ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Equilibrium Form ◽  
Temperature Coefficients ◽  
Recombination Rate Constant ◽  
Arrhenius Temperature

It is shown that previously calculated nonequilibrium rate constants for the dissociation of H2 and D2 appear to approach a rotationally averaged equilibrium expression at low temperature. This equilibrium form of the rate expression itself has an Arrhenius temperature coefficient for dissociation which is significantly less than the dissociation energy, and the corresponding recombination rate constant has a negative temperature coefficient. The reasons for this are explained.

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